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Sample records for bacteriophage felix o1

  1. The genome and proteome of a virulent Escherichia coli O157:H7 bacteriophage closely resembling Salmonella phage Felix O1

    Directory of Open Access Journals (Sweden)

    Waddell Thomas E

    2009-04-01

    Full Text Available Abstract Based upon whole genome and proteome analysis, Escherichia coli O157:H7-specific bacteriophage (phage wV8 belongs to the new myoviral genus, "the Felix O1-like viruses" along with Salmonella phage Felix O1 and Erwinia amylovora phage φEa21-4. The genome characteristics of phage wV8 (size 88.49 kb, mol%G+C 38.9, 138 ORFs, 23 tRNAs are very similar to those of phage Felix O1 (86.16 kb, 39.0 mol%G+C, 131 ORFs and 22 tRNAs and, indeed most of the proteins have their closest homologs within Felix O1. Approximately one-half of the Escherichia coli O157:H7 mutants resistant to phage wV8 still serotype as O157:H7 indicating that this phage may recognize, like coliphage T4, two different surface receptors: lipopolysaccharide and, perhaps, an outer membrane protein.

  2. New Vibrio cholerae O1 Biotype ElTor bacteriophages

    Directory of Open Access Journals (Sweden)

    Sen Anindito

    2005-04-01

    Full Text Available Abstract We report the presence of three new O1 ElTor vibriophages named AS1, AS2 and AS3, isolated from the sewage and pond waters of the outskirts of Kolkata. A few phages, named AS4, with hexagonal heads and abnormally long tails with typical curly projections were also found in the water samples.

  3. Phase variable O antigen biosynthetic genes control expression of the major protective antigen and bacteriophage receptor in Vibrio cholerae O1.

    Directory of Open Access Journals (Sweden)

    Kimberley D Seed

    2012-09-01

    Full Text Available The Vibrio cholerae lipopolysaccharide O1 antigen is a major target of bacteriophages and the human immune system and is of critical importance for vaccine design. We used an O1-specific lytic bacteriophage as a tool to probe the capacity of V. cholerae to alter its O1 antigen and identified a novel mechanism by which this organism can modulate O antigen expression and exhibit intra-strain heterogeneity. We identified two phase variable genes required for O1 antigen biosynthesis, manA and wbeL. manA resides outside of the previously recognized O1 antigen biosynthetic locus, and encodes for a phosphomannose isomerase critical for the initial step in O1 antigen biosynthesis. We determined that manA and wbeL phase variants are attenuated for virulence, providing functional evidence to further support the critical role of the O1 antigen for infectivity. We provide the first report of phase variation modulating O1 antigen expression in V. cholerae, and show that the maintenance of these phase variable loci is an important means by which this facultative pathogen can generate the diverse subpopulations of cells needed for infecting the host intestinal tract and for escaping predation by an O1-specific phage.

  4. Felix Nussbaum (1904-1944

    Directory of Open Access Journals (Sweden)

    Luiz Nazario

    2014-05-01

    Full Text Available O artigo descreve a perseguição nazista e as tentativas de fuga do mais trágico de todos os pintores trágicos: Felix Nussbaum, que encarnou em sua vida e em sua obra uma tragédia sem nome, à qual chamamos, inadequadamente, de Holocausto (ou de Shoah, sem conseguir definir precisamente sua dimensão, uma tragédia que não foi produzida pela natureza, nem pelas condições gerais da vida, mas pelo Estado mais poderoso da Europa contra uma minoria então sem Estado, perseguida em toda parte.

  5. Bacteriophages, revitalized after 100 years in the shadow of antibiotics

    Institute of Scientific and Technical Information of China (English)

    Hongping; Wei

    2015-01-01

    <正>The year 2015 marks 100 years since Dr.Frederick Twort discovered the"filterable lytic factor",which was later independently discovered and named "bacteriophage" by Dr.Felix d’Herelle.On this memorable centennial,it is exciting to see a special issue published by Virologica Sinica on Phages and Therapy.In this issue,readers will not only fi nd that bacteriophage research is a

  6. Genomics of Three New Bacteriophages Useful in the Biocontrol of Salmonella.

    Science.gov (United States)

    Bardina, Carlota; Colom, Joan; Spricigo, Denis A; Otero, Jennifer; Sánchez-Osuna, Miquel; Cortés, Pilar; Llagostera, Montserrat

    2016-01-01

    Non-typhoid Salmonella is the principal pathogen related to food-borne diseases throughout the world. Widespread antibiotic resistance has adversely affected human health and has encouraged the search for alternative antimicrobial agents. The advances in bacteriophage therapy highlight their use in controlling a broad spectrum of food-borne pathogens. One requirement for the use of bacteriophages as antibacterials is the characterization of their genomes. In this work, complete genome sequencing and molecular analyses were carried out for three new virulent Salmonella-specific bacteriophages (UAB_Phi20, UAB_Phi78, and UAB_Phi87) able to infect a broad range of Salmonella strains. Sequence analysis of the genomes of UAB_Phi20, UAB_Phi78, and UAB_Phi87 bacteriophages did not evidence the presence of known virulence-associated and antibiotic resistance genes, and potential immunoreactive food allergens. The UAB_Phi20 genome comprised 41,809 base pairs with 80 open reading frames (ORFs); 24 of them with assigned function. Genome sequence showed a high homology of UAB_Phi20 with Salmonella bacteriophage P22 and other P22likeviruses genus of the Podoviridae family, including ST64T and ST104. The DNA of UAB_Phi78 contained 44,110 bp including direct terminal repeats (DTR) of 179 bp and 58 putative ORFs were predicted and 20 were assigned function. This bacteriophage was assigned to the SP6likeviruses genus of the Podoviridae family based on its high similarity not only with SP6 but also with the K1-5, K1E, and K1F bacteriophages, all of which infect Escherichia coli. The UAB_Phi87 genome sequence consisted of 87,669 bp with terminal direct repeats of 608 bp; although 148 ORFs were identified, putative functions could be assigned to only 29 of them. Sequence comparisons revealed the mosaic structure of UAB_Phi87 and its high similarity with bacteriophages Felix O1 and wV8 of E. coli with respect to genetic content and functional organization. Phylogenetic analysis of large

  7. Genomics of three new bacteriophages useful in the biocontrol of Salmonella

    Directory of Open Access Journals (Sweden)

    Carlota eBardina

    2016-04-01

    Full Text Available Non-typhoid Salmonella is the principal pathogen related to food-borne diseases throughout the world. Widespread antibiotic resistance has adversely affected human health and has encouraged the search for alternative antimicrobial agents. The advances in bacteriophage therapy highlight their use in controlling a broad spectrum of food-borne pathogens. One requirement for the use of bacteriophages as antibacterials is the characterization of their genomes. In this work, complete genome sequencing and molecular analyses were carried out for three new virulent Salmonella-specific bacteriophages (UAB_Phi20, UAB_Phi78, and UAB_Phi87 able to infect a broad range of Salmonella strains. Sequence analysis of the genomes of UAB_Phi20, UAB_Phi78, and UAB_Phi87 bacteriophages did not evidence the presence of known virulence-associated and antibiotic resistance genes, and potential immunoreactive food allergens. The UAB_Phi20 genome comprised 41,809 base pairs with 80 open reading frames (ORFs; 24 of them with assigned function. Genome sequence showed a high homology of UAB_Phi20 with Salmonella bacteriophage P22 and other P22likeviruses genus of the Podoviridae family, including ST64T and ST104. The DNA of UAB_Phi78 contained 44,110 bp including direct terminal repeats of 179 bp and 58 putative ORFs were predicted and 20 were assigned function. This bacteriophage was assigned to the SP6likeviruses genus of the Podoviridae family based on its high similarity not only with SP6 but also with the K1-5, K1E, and K1F bacteriophages, all of which infect Escherichia coli. The UAB_Phi87 genome sequence consisted of 87,669 bp with terminal direct repeats of 608 bp; although 148 ORFs were identified, putative functions could be assigned to only 29 of them. Sequence comparisons revealed the mosaic structure of UAB_Phi87 and its high similarity with bacteriophages Felix O1 and wV8 of E. coli with respect to genetic content and functional organization. Phylogenetic

  8. A full-acceptance detector at the LHC (FELIX)

    CERN Document Server

    Ageev, A N; Alvero, L; Amelino-Camelia, G; Avati, V; Baier, R; Bartels, Julius; Baur, G; Beneke, Martin; Berera, A; Bjorken, James D; Bondila, M; Britvich, G I; Capella, A; Close, Francis Edwin; Collins, J; Costa, C; Cudell, J R; Derevshchikov, A A; Dick, Louis; Dzhordzhadze, V; Dokshitzer, Y; Dormachie, A; Eggert, Karsten; Engel, R; Frankfurt, L L; Kinder-Geiger, Klaus; Giovannini, Alberto; Goloskokov, S V; Goulianos, K; Gridasov, V I; Gustafson, H R; Halzen, Francis; Hencken, K; Inyakin, A V; Islam, M M; Jones, L; Kaidalov, A B; Karapetian, G V; Karapetian, V V; Karpushov, I D; Kashtanov, E; Kharlov, Yu V; Khoze, V; Klein, S; Klimenko, E Y; Kozlov, O; Kowalski, K L; Kubarovsky, A V; Landshoff, Peter V; Leflat, A; Lippmaa, E; Manankov, V M; Marchesini, G; Medvedkov, A M; Mokhnatuk, V A; Müller, A H; Murzin, V S; Myznikov, K P; Nikitin, V A; Nomokonov, V P; Novikov, S I; Orava, Risto; Ostonen, R; Uvarov, V; Papageorgiou, E; Polyakov, V; Raidal, Martti; Rainwater, D L; Ranft, J; Riege, H; Rufanov, I A; Rubin, N; Sadovsky, S A; Salam, Gavin P; Sauli, Fabio; Schiff, D; Selyugin, O V; Shabalina, E K; Shabratova, G; Shuvalov, R S; Smirnov, V; Strikman, M I; Subbi, J; Sytnik, V V; Taylor, C; Tikhonova, L A; Toukhtarov, A; Treleani, D; Ugoccioni, R; Vasilchenko, V G; Vasilev, A; Vasiliev, L; White, A; Whitmore, J; Wlodarczyk, Z; Yakovlev, V; Yushchenko, O P; Zeppenfeld, Dieter; Zhalov, M B; Zinchenko, S I; Zotov, N P

    2002-01-01

    The FELIX collaboration had proposed the construction of a full- acceptance detector for the LHC. The primary mission of FELIX was the study of QCD: to provide comprehensive and definitive observations of a very broad range of strong-interaction processes. This document contains an extensive discussion of this physics menu. In a further paper the FELIX detector will be reviewed. (172 refs).

  9. Control of Escherichia coli O157 on beef at 37, 22 and 4 °C by T5-, T1-, T4-and O1-like bacteriophages.

    Science.gov (United States)

    Liu, H; Niu, Y D; Meng, R; Wang, J; Li, J; Johnson, R P; McAllister, T A; Stanford, K

    2015-10-01

    Efficacy of four bacteriophages (phages) and a cocktail for biocontrol of Escherichia coli O157 was assessed on beef samples stored at 4, 22 and 37 °C. Samples (3 × 3 × 1 cm) were contaminated with E. coli O157 (10(4) CFU/cm(2)) and treated with single phages: T5-like (T5), T1-like (T1), T4-like (T4) and O1-like (O1), or a cocktail at two titers: multiplicity of infection (MOI) = 1000 and MOI = 10. In contrast to previous studies, use of virucidal solution prevented over-estimation of phage efficacy. Irrespective of temperature and MOIs, T5 was most (P supply chain includes hours of storage or transport at temperatures near 4 °C, this study demonstrates phages could significantly reduce E. coli O157 during this period. PMID:26187829

  10. Felix Adler and Education for Ethical Culture

    Science.gov (United States)

    Stallones, Jared R.

    2015-01-01

    This article delves into the various religious influences on Dr. Felix Adler's spiritual development and the resulting theological and philosophical foundations for the Ethical Culture Society that he created in addition to the Society's schools. The discussion focuses on Dr. Adler's personal struggles with traditional Judaism in the face of…

  11. The Impact of the Felix Consent Decree.

    Science.gov (United States)

    Wataoka, Phuong

    This paper reviews the literature on the background, legal process, and implications of the Felix consent decree, a legal settlement in which the State of Hawaii agreed to improve its special education program and to develop a self-sustaining system of care for delivering special education services. The paper begins by reviewing federal laws (the…

  12. Tribute to Erwin Felix Lewy-Bertaut

    International Nuclear Information System (INIS)

    Erwin Lewy (alias Felix Bertaut) was born in 1913 in Germany, he emigrated to France where he undertook graduate studies in chemistry. Then, he joined the powder central laboratory where he learnt how to use international tables for structure determination. His thesis work was the X-ray study of the statistical distribution of the size of iron grains. The method Bertaut developed is still a reference in powder granulometry. Bertaut was also interested in the nascent neutron diffraction method and he flew to the United-States to improve his knowledge on this topic. Felix Bertaut created the neutron diffraction laboratory in the atomic research center in Grenoble and later he headed the CNRS' crystallography laboratory till 1982. Felix Bertaut and his laboratories became internationally renowned in crystallography, neutron diffraction and magnetism. He favored the scientific cooperation between France and Germany that led to the creation of the Laue-Langevin Institute (ILL). The ILL became European and was a key partner for building the European Synchrotron Facility (ESRF) in Grenoble. Bertaut was elected as a full member of the French Academy of Sciences in 1979, he died in 2003. (A.C.)

  13. FELIX: the detector readout upgrade of the ATLAS experiment

    CERN Document Server

    Ryu, Soo; The ATLAS collaboration

    2015-01-01

    After the Phase-I upgrade and onward, the Front-End Link eXchange(FELIX) system will be the interface between the readout system and the detector front-end electronics and trigger electronics at the ATLAS experiment. FELIX will function as a gateway to a commodity switched network which will use standard technologies (Ethernet or Infiniband) to communicate with data collecting and processing components. In this talk the system architecture of FELIX will be described and the testing results of the FELIX demonstrator will be presented

  14. The search for therapeutic bacteriophages uncovers one new subfamily and two new genera of Pseudomonas-infecting Myoviridae.

    Directory of Open Access Journals (Sweden)

    Marine Henry

    Full Text Available In a previous study, six virulent bacteriophages PAK_P1, PAK_P2, PAK_P3, PAK_P4, PAK_P5 and CHA_P1 were evaluated for their in vivo efficacy in treating Pseudomonas aeruginosa infections using a mouse model of lung infection. Here, we show that their genomes are closely related to five other Pseudomonas phages and allow a subdivision into two clades, PAK_P1-like and KPP10-like viruses, based on differences in genome size, %GC and genomic contents, as well as number of tRNAs. These two clades are well delineated, with a mean of 86% and 92% of proteins considered homologous within individual clades, and 25% proteins considered homologous between the two clades. By ESI-MS/MS analysis we determined that their virions are composed of at least 25 different proteins and electron microscopy revealed a morphology identical to the hallmark Salmonella phage Felix O1. A search for additional bacteriophage homologs, using profiles of protein families defined from the analysis of the 11 genomes, identified 10 additional candidates infecting hosts from different species. By carrying out a phylogenetic analysis using these 21 genomes we were able to define a new subfamily of viruses, the Felixounavirinae within the Myoviridae family. The new Felixounavirinae subfamily includes three genera: Felixounalikevirus, PAK_P1likevirus and KPP10likevirus. Sequencing genomes of bacteriophages with therapeutic potential increases the quantity of genomic data on closely related bacteriophages, leading to establishment of new taxonomic clades and the development of strategies for analyzing viral genomes as presented in this article.

  15. [The removal of salmonellae in waste water by bacteriophages (author's transl)].

    Science.gov (United States)

    Müller, H E

    1980-02-01

    Sewage treatment plants show only a 90-99% reduction in numbers of salmonellae. And the following chlorination of the effluents produces chlorinated organic derivatives and these are likely to be of great long term environmental danger. Thus for reasons of hygiene, it is desirable to study biological methods to remove salmonellae in waste waster. Therefore, the efficiency of the Felix O 1-bacteriophage for the removal of S. schottmuelleri and S. typhimurium was investigated. The composition and the pH of the medium (Destilled water, Sörensen phosphate buffer solution, pH 6.0-8.0, and sterilized wate water, pH 6.5) seem not to have a considerable importance for the observed salmonellae removal efficiency. As it is shown, the reduction of salmonellae by the O 1-phages is dependent on their concentration (Fig. 1). It is true, there is 90-99% removal of salmonellae as a function of their concentration, but a perfect elimination is not possible.

  16. FELIX : The new detector readout system for the ATLAS experiment

    CERN Document Server

    Ryu, Soo; The ATLAS collaboration

    2016-01-01

    After the Phase-I upgrade and onward, the Front-End Link eXchange (FELIX) system will be the interface between the data handling system and the detector front-end electronics and trigger electronics at the ATLAS experiment. FELIX will function as a router between custom serial links and a commodity switch network which will use standard technologies (Ethernet or Infiniband) to communicate with data collecting and processing components. The system architecture of FELIX will be described and the results of the demonstrator program currently in progress will be presented.

  17. Tribute to Erwin Felix Lewy-Bertaut; Hommage a Erwin Felix Lewy-Bertaut

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    Erwin Lewy (alias Felix Bertaut) was born in 1913 in Germany, he emigrated to France where he undertook graduate studies in chemistry. Then, he joined the powder central laboratory where he learnt how to use international tables for structure determination. His thesis work was the X-ray study of the statistical distribution of the size of iron grains. The method Bertaut developed is still a reference in powder granulometry. Bertaut was also interested in the nascent neutron diffraction method and he flew to the United-States to improve his knowledge on this topic. Felix Bertaut created the neutron diffraction laboratory in the atomic research center in Grenoble and later he headed the CNRS' crystallography laboratory till 1982. Felix Bertaut and his laboratories became internationally renowned in crystallography, neutron diffraction and magnetism. He favored the scientific cooperation between France and Germany that led to the creation of the Laue-Langevin Institute (ILL). The ILL became European and was a key partner for building the European Synchrotron Facility (ESRF) in Grenoble. Bertaut was elected as a full member of the French Academy of Sciences in 1979, he died in 2003. (A.C.)

  18. Research into communication between L1DDC and FELIX

    CERN Document Server

    Keser, Marceline

    2016-01-01

    This report describes the summer student project of Marceline Keser, performed with the team for the New Small Wheel electronics upgrade of ATLAS. The main goal of the project is to create communication between the FELIX and L1DDC, in order to create a bidirectional data transmission. During this project, research has been done and has resulted in a GBT link between the L1DDC and FELIX.

  19. Campylobacter bacteriophages and bacteriophage therapy.

    Science.gov (United States)

    Connerton, P L; Timms, A R; Connerton, I F

    2011-08-01

    Members of the genus Campylobacter are frequently responsible for human enteric disease with occasionally very serious outcomes. Much of this disease burden is thought to arise from consumption of contaminated poultry products. More than 80% of poultry in the UK harbour Campylobacter as a part of their intestinal flora. To address this unacceptably high prevalence, various interventions have been suggested and evaluated. Among these is the novel approach of using Campylobacter-specific bacteriophages, which are natural predators of the pathogen. To optimize their use as therapeutic agents, it is important to have a comprehensive understanding of the bacteriophages that infect Campylobacter, and how they can affect their host bacteria. This review will focus on many aspects of Campylobacter-specific bacteriophages including: their first isolation in the 1960s, their use in bacteriophage typing schemes, their isolation from the different biological sources and genomic characterization. As well as their use as therapeutic agents to reduce Campylobacter in poultry their future potential, including their use in bio-sanitization of food, will be explored. The evolutionary consequences of naturally occurring bacteriophage infection that have come to light through investigations of bacteriophages in the poultry ecosystem will also be discussed.

  20. Incomplete LPS Core-Specific Felix01-Like Virus vB_EcoM_VpaE1.

    Science.gov (United States)

    Šimoliūnas, Eugenijus; Vilkaitytė, Monika; Kaliniene, Laura; Zajančkauskaitė, Aurelija; Kaupinis, Algirdas; Staniulis, Juozas; Valius, Mindaugas; Meškys, Rolandas; Truncaitė, Lidija

    2015-11-27

    Bacteriophages represent a valuable source for studying the mechanisms underlying virus-host interactions. A better understanding of the host-specificity of viruses at the molecular level can promote various phage applications, including bacterial diagnostics, antimicrobial therapeutics, and improve methods in molecular biology. In this study, we describe the isolation and characterization of a novel coliphage, vB_EcoM_VpaE1, which has different host specificity than its relatives. Morphology studies, coupled with the results of genomic and proteomic analyses, indicate that vB_EcoM_VpaE1 belongs to the newly proposed genus Felix01likevirus in the family Myoviridae. The genus Felix01likevirus comprises a group of highly similar phages that infect O-antigen-expressing Salmonella and Escherichia coli (E. coli) strains. Phage vB_EcoM_VpaE1 differs from the rest of Felix01-like viruses, since it infects O-antigen-deficient E. coli strains with an incomplete core lipopolysaccharide (LPS). We show that vB_EcoM_VpaE1 can infect mutants of E. coli that contain various truncations in their LPS, and can even recognize LPS that is truncated down to the inner-core oligosaccharide, showing potential for the control of rough E. coli strains, which usually emerge as resistant mutants upon infection by O-Ag-specific phages. Furthermore, VpaE1 can replicate in a wide temperature range from 9 to 49 °C, suggesting that this virus is well adapted to harsh environmental conditions. Since the structural proteins of such phages tend to be rather robust, the receptor-recognizing proteins of VpaE1 are an attractive tool for application in glycan analysis, bacterial diagnostics and antimicrobial therapeutics.

  1. Incomplete LPS Core-Specific Felix01-Like Virus vB_EcoM_VpaE1

    Directory of Open Access Journals (Sweden)

    Eugenijus Šimoliūnas

    2015-11-01

    Full Text Available Bacteriophages represent a valuable source for studying the mechanisms underlying virus-host interactions. A better understanding of the host-specificity of viruses at the molecular level can promote various phage applications, including bacterial diagnostics, antimicrobial therapeutics, and improve methods in molecular biology. In this study, we describe the isolation and characterization of a novel coliphage, vB_EcoM_VpaE1, which has different host specificity than its relatives. Morphology studies, coupled with the results of genomic and proteomic analyses, indicate that vB_EcoM_VpaE1 belongs to the newly proposed genus Felix01likevirus in the family Myoviridae. The genus Felix01likevirus comprises a group of highly similar phages that infect O-antigen-expressing Salmonella and Escherichia coli (E. coli strains. Phage vB_EcoM_VpaE1 differs from the rest of Felix01-like viruses, since it infects O-antigen-deficient E. coli strains with an incomplete core lipopolysaccharide (LPS. We show that vB_EcoM_VpaE1 can infect mutants of E. coli that contain various truncations in their LPS, and can even recognize LPS that is truncated down to the inner-core oligosaccharide, showing potential for the control of rough E. coli strains, which usually emerge as resistant mutants upon infection by O-Ag-specific phages. Furthermore, VpaE1 can replicate in a wide temperature range from 9 to 49 °C, suggesting that this virus is well adapted to harsh environmental conditions. Since the structural proteins of such phages tend to be rather robust, the receptor-recognizing proteins of VpaE1 are an attractive tool for application in glycan analysis, bacterial diagnostics and antimicrobial therapeutics.

  2. Pühapäine Felix Randel / Maire Toom

    Index Scriptorium Estoniae

    Toom, Maire

    2002-01-01

    8. II-7. IV Adamson-Ericu muuseumis maalikunstniku ja karikaturisti Felix Randeli 100. sünnipäeva tähistav näitus "Sünnipäev". Põhirõhk on kubistlikul ja art decolikul maaliloomingul, esitatud ka valik karikatuure ja sharzhe ning kubistliku perioodi kavandeid. Kuraator Maire Toom

  3. FELIX - the new detector readout system for the ATLAS experiment

    CERN Document Server

    AUTHOR|(SzGeCERN)754725; The ATLAS collaboration; Anderson, John Thomas; Borga, Andrea; Boterenbrood, Hendrik; Chen, Hucheng; Chen, Kai; Drake, Gary; Donszelmann, Mark; Francis, David; Gorini, Benedetto; Guest, Daniel; Lanni, Francesco; Lehmann Miotto, Giovanna; Levinson, Lorne; Roich, Alexander; Schreuder, Frans Philip; Schumacher, J\\"orn; Vandelli, Wainer; Vermeulen, Jos; Wu, Weihao; Zhang, Jinlong

    2016-01-01

    From the ATLAS Phase-I upgrade and onward, new or upgraded detectors and trigger systems will be interfaced to the data acquisition, detector control and timing (TTC) systems by the Front-End Link eXchange (FELIX). FELIX is the core of the new ATLAS Trigger/DAQ architecture. Functioning as a router between custom serial links and a commodity network, FELIX is implemented by server PCs with commodity network interfaces and PCIe cards with large FPGAs and many high speed serial fiber transceivers. By separating data transport from data manipulation, the latter can be done by software in commodity servers attached to the network. Replacing traditional point-to-point links between Front-end components and the DAQ system by a switched network, FELIX provides scaling, flexibility uniformity and upgradability. Different Front-end data types or different data sources can be routed to different network endpoints that handle that data type or source: e.g. event data, configuration, calibration, detector control, monito...

  4. Chlamydia bacteriophages.

    Science.gov (United States)

    Śliwa-Dominiak, Joanna; Suszyńska, Ewa; Pawlikowska, Małgorzata; Deptuła, Wiesław

    2013-11-01

    Phages are called "good viruses" due to their ability to infect and kill pathogenic bacteria. Chlamydia are small, Gram-negative (G-) microbes that can be dangerous to human and animals. In humans, these bacteria are etiological agents of diseases such as psittacosis or respiratory tract diseases, while in animals, the infection may result in enteritis in cattle and chronic bowel diseases, as well as miscarriages in sheep. The first-known representative of chlamydiaphages was Chp1. It was discovered in Chlamydia psittaci isolates. Since then, four more species of chlamydiaphages have been identified [Chp2, Chp3, φCPG1 φCPAR39 (φCpn1) and Chp4]. All of them were shown to infect Chlamydia species. This paper described all known chlamydiaphages. They were characterised in terms of origin, host range, and their molecular structure. The review concerns the characterisation of bacteriophages that infects pathogenic and dangerous bacteria with unusual, intracellular life cycles that are pathogenic. In the era of antibiotic resistance, it is difficult to cure chlamydophilosis. Those bacteriophages can be an alternative to antibiotics, but before this happens, we need to get to know chlamydiaphages better. PMID:23903989

  5. Improving Packet Processing Performance in the ATLAS FELIX Project

    CERN Document Server

    Schumacher, Jorn; The ATLAS collaboration; Borga, Andrea; Boterenbrood, Hendrik; Chen, Hucheng; Chen, Kai; Drake, Gary; Francis, David; Gorini, Benedetto; Lanni, Francesco; Lehmann Miotto, Giovanna; Levinson, Lorne; Narevicius, Julia; Roich, Alexander; Ryu, Soo; Schreuder, Frans Philip; Vandelli, Wainer; Zhang, Jinlong; Vermeulen, Jos

    2015-01-01

    Experiments in high-energy physics (HEP) and related fields often impose constraints and challenges on data acquisition systems. As a result, these systems are implemented as unique mixtures of custom and commercial-off-the-shelf electronics (COTS), involving and connecting radiation-hard devices, large high-performance networks, and computing farms. FELIX, the Frontend Link Exchange, is a new PC-based general purpose data routing device for the data-acquisition system of the ATLAS experiment at CERN. Performance is a very crucial point for devices like FELIX, which have to be capable of processing tens of gigabyte of data per second. Thus it is important to understand the performance limitations for typical workloads on modern hardware. We present an analysis of a packet processing algorithm that is used in FELIX, and show how the PC system's memory architecture plays a key factor in the overall data throughput achieved by the application. Finally, we present optimizations that increase the processing throug...

  6. New Cytotoxic 24-Homoscalarane Sesterterpenoids from the Sponge Ircinia felix

    Directory of Open Access Journals (Sweden)

    Ya-Yuan Lai

    2015-09-01

    Full Text Available Two new 24-homoscalarane sesterterpenoids, felixins F (1 and G (2, were isolated from the sponge Ircinia felix. The structures of new homoscalaranes 1 and 2 were elucidated by extensive spectroscopic methods, particularly with one-dimensional (1D and two-dimensional (2D NMR, and, by comparison, the spectral data with those of known analogues. The cytotoxicity of 1 and 2 against the proliferation of a limited panel of tumor cell lines was evaluated and 1 was found to show cytotoxicity toward the leukemia K562, MOLT-4, and SUP-T1 cells (IC50 ≤ 5.0 μM.

  7. Felix de Roy: a life of variable stars

    CERN Document Server

    Shears, Jeremy

    2010-01-01

    Felix de Roy (1883-1942), an internationality recognised amateur astronomer, made significant contributions to variable star research. As an active observer, he made some 91,000 visual estimates of a number of different variable stars. A Belgian national, he took refuge in England during World War 1. While there, de Roy became well enough known to later serve as Director of the BAA Variable Star Section for seventeen years. Through this office, and his connections with other organisations around the world, he encouraged others to pursue the observation of variable stars. Not merely content to accumulate observational data, de Roy also analysed the data and published numerous papers.

  8. Jüdische Musikelemente im Werk von Felix Mendelssohn

    OpenAIRE

    Herbst, Raviv

    2012-01-01

    The dissertation examines the influence of Jewish Music elements on Felix Mendelssohn and his work. But what is meant by the term "Jewish music"? Why this term is really so controversial? One answer lies in the almost two thousand years of dispersion of the Jewish people. In general, a certain musical genre is associated with a place or region in which it arises and to which it is inextricably linked. Meanwhile, a part of the Jewish people remained in the region, which is now Israel and Pales...

  9. New Cytotoxic 24-Homoscalarane Sesterterpenoids from the Sponge Ircinia felix.

    Science.gov (United States)

    Lai, Ya-Yuan; Chen, Li-Chai; Wu, Chug-Fung; Lu, Mei-Chin; Wen, Zhi-Hong; Wu, Tung-Ying; Fang, Lee-Shing; Wang, Li-Hsueh; Wu, Yang-Chang; Sung, Ping-Jyun

    2015-09-11

    Two new 24-homoscalarane sesterterpenoids, felixins F (1) and G (2), were isolated from the sponge Ircinia felix. The structures of new homoscalaranes 1 and 2 were elucidated by extensive spectroscopic methods, particularly with one-dimensional (1D) and two-dimensional (2D) NMR, and, by comparison, the spectral data with those of known analogues. The cytotoxicity of 1 and 2 against the proliferation of a limited panel of tumor cell lines was evaluated and 1 was found to show cytotoxicity toward the leukemia K562, MOLT-4, and SUP-T1 cells (IC50 ≤ 5.0 μM).

  10. Bacteriophages Infecting Propionibacterium acnes

    Directory of Open Access Journals (Sweden)

    Holger Brüggemann

    2013-01-01

    Full Text Available Viruses specifically infecting bacteria, or bacteriophages, are the most common biological entity in the biosphere. As such, they greatly influence bacteria, both in terms of enhancing their virulence and in terms of killing them. Since the first identification of bacteriophages in the beginning of the 20th century, researchers have been fascinated by these microorganisms and their ability to eradicate bacteria. In this review, we will cover the history of the Propionibacterium acnes bacteriophage research and point out how bacteriophage research has been an important part of the research on P. acnes itself. We will further discuss recent findings from phage genome sequencing and the identification of phage sequence signatures in clustered regularly interspaced short palindromic repeats (CRISPRs. Finally, the potential to use P. acnes bacteriophages as a therapeutic strategy to combat P. acnes-associated diseases will be discussed.

  11. Bacteriophages infecting Propionibacterium acnes.

    Science.gov (United States)

    Brüggemann, Holger; Lood, Rolf

    2013-01-01

    Viruses specifically infecting bacteria, or bacteriophages, are the most common biological entity in the biosphere. As such, they greatly influence bacteria, both in terms of enhancing their virulence and in terms of killing them. Since the first identification of bacteriophages in the beginning of the 20th century, researchers have been fascinated by these microorganisms and their ability to eradicate bacteria. In this review, we will cover the history of the Propionibacterium acnes bacteriophage research and point out how bacteriophage research has been an important part of the research on P. acnes itself. We will further discuss recent findings from phage genome sequencing and the identification of phage sequence signatures in clustered regularly interspaced short palindromic repeats (CRISPRs). Finally, the potential to use P. acnes bacteriophages as a therapeutic strategy to combat P. acnes-associated diseases will be discussed.

  12. FELIX: The New Approach for Interfacing to Front-end Electronics for the ATLAS Experiment

    CERN Document Server

    AUTHOR|(SzGeCERN)754725; The ATLAS collaboration; Anderson, John Thomas; Borga, Andrea; Boterenbrood, Hendrik; Chen, Hucheng; Chen, Kai; Drake, Gary; Donszelmann, Mark; Francis, David; Gorini, Benedetto; Guest, Daniel; Lanni, Francesco; Lehmann Miotto, Giovanna; Levinson, Lorne; Roich, Alexander; Schreuder, Frans Philip; Schumacher, J\\"orn; Vandelli, Wainer; Zhang, Jinlong

    2016-01-01

    From the ATLAS Phase-I upgrade and onward, new or upgraded detectors and trigger systems will be interfaced to the data acquisition, detector control and timing (TTC) systems by the Front-End Link eXchange (FELIX). FELIX is the core of the new ATLAS Trigger/DAQ architecture. Functioning as a router between custom serial links and a commodity network, FELIX is implemented by server PCs with commodity network interfaces and PCIe cards with large FPGAs and many high speed serial fiber transceivers. By separating data transport from data manipulation, the latter can be done by software in commodity servers attached to the network. Replacing traditional point-to-point links between Front-end components and the DAQ system by a switched network, FELIX provides scaling, flexibility uniformity and upgradability and reduces the diversity of custom hardware solutions in favour of software.

  13. Summary of sensor evaluation for the Fusion ELectromagnetic Induction eXperiment (FELIX)

    International Nuclear Information System (INIS)

    As part of the First Wall/Blanket/Shield Engineering Test Program, a test bed called FELIX (Fusion ELectromagnetic Induction eXperiment) is now under construction at ANL. Its purpose will be to test, evaluate, and develop computer codes for the prediction of electromagnetically induced phenomenon in a magnetic environment modeling that of a fusion reaction. Crucial to this process is the sensing and recording of the various induced effects. Sensor evaluation for FELIX has reached the point where most sensor types have been evaluated and preliminary decisions are being made as to type and quantity for the initial FELIX experiments. These early experiments, the first, flat plate experiment in particular, will be aimed at testing the sensors as well as the pertinent theories involved. The reason for these evaluations, decisions, and proof tests is the harsh electrical and magnetic environment that FELIX presents

  14. Development of hardware configuration and testing tools for the FELIX project.

    CERN Document Server

    Rodriguez, Alberto

    2015-01-01

    This document contains a report about the work I have been doing during my stay as a summer student at CERN. The work described here is part of the FELIX project, a new system that will be progressively integrated in the ATLAS Data Acquisition System during Long Shutdowns 2 and 3. Specifically, my task consisted of the development of testing and configuration software for FELIX.

  15. Prof. dr. Felix Oinase mälestusõhtu külalisesinejad

    Index Scriptorium Estoniae

    2005-01-01

    on Jaan Undusk, kirjandusteadlane, kirjanik, Felix Oinase elutöö tundja Eestis. Tema ettekande teemaks on "Mõnda Felix Oinase teaduslikust mõtteviisist". New Yorki tuleb ka Jaani abikaasa Maarja Undusk, kes on kirjanik, kunstnik ja raamatuillustraator, tema toob külakostiks kaasa näituse oma töödest. Muusikaliseks esinejaks on kandlemängija Tiit Kao Kanadast. Ettekannete õhtu korraldab Eesti Kultuurifond Ameerika Ühendriikides 12. novembril 2005 New Yorgi Eesti Majas

  16. Bacteriophages and Biofilms

    Directory of Open Access Journals (Sweden)

    David R. Harper

    2014-06-01

    Full Text Available Biofilms are an extremely common adaptation, allowing bacteria to colonize hostile environments. They present unique problems for antibiotics and biocides, both due to the nature of the extracellular matrix and to the presence within the biofilm of metabolically inactive persister cells. Such chemicals can be highly effective against planktonic bacterial cells, while being essentially ineffective against biofilms. By contrast, bacteriophages seem to have a greater ability to target this common form of bacterial growth. The high numbers of bacteria present within biofilms actually facilitate the action of bacteriophages by allowing rapid and efficient infection of the host and consequent amplification of the bacteriophage. Bacteriophages also have a number of properties that make biofilms susceptible to their action. They are known to produce (or to be able to induce enzymes that degrade the extracellular matrix. They are also able to infect persister cells, remaining dormant within them, but re-activating when they become metabolically active. Some cultured biofilms also seem better able to support the replication of bacteriophages than comparable planktonic systems. It is perhaps unsurprising that bacteriophages, as the natural predators of bacteria, have the ability to target this common form of bacterial life.

  17. Bacteriophages and cancer.

    Science.gov (United States)

    Budynek, Paulina; Dabrowska, Krystyna; Skaradziński, Grzegorz; Górski, Andrzej

    2010-05-01

    Bacteriophages can be used effectively to cure bacterial infections. They are known to be active against bacteria but inactive against eukaryotic cells. Nevertheless, novel observations suggest that phages are not neutral for higher organisms. They can affect physiological and immunological processes which may be crucial to their expected positive effects in therapies. Bacteriophages are a very differentiated group of viruses and at least some of them can influence cancer processes. Phages may also affect the immunological system. In general, they activate the immunological response, for example cytokine secretion. They can also switch the tumor microenvironment to one advantageous for anticancer treatment. On the other hand, bacteriophages are used as a platform for foreign peptides that may induce anticancer effects. As bacterial debris can interfere with bacteriophage activity, phage purification is significant for the final effect of a phage preparation. In this review, results of the influence of bacteriophages on cancer processes are presented which have implications for the perspective application of phage therapy in patients with cancer and the general understanding of the role of bacteriophages in the human organism.

  18. Told by a myth: Thomas Mann’s Felix Krull

    Directory of Open Access Journals (Sweden)

    Montiel, Luis

    2013-12-01

    Full Text Available This article proposes an approach to the novel Bekenntnisse des Hochstaplers Felix Krull by Thomas Mann from the point of view of the imaginal psychology of James Hillman. From this perspective the novel seems to illustrate the most innovative thesis of that psychology, which is especially relevant for having been written prior to the formulation of Hillman’s theories. The unplanned correspondence between both ways of thinking furnishes a valuable argument that supports the new conception of human psyche introduced by Carl Gustav Jung and developed in this way by James Hillman.El presente artículo propone una lectura de la novela de Thomas Mann desde la óptica de la psicología imaginal de James Hillman. En esta perspectiva la novela parece ofrecer una ilustración de las tesis más innovadoras de dicha psicología, lo que resulta especialmente relevante por haber sido escrita con antelación a la formulación de las teorías del pensador estadounidense. La impremeditada correspondencia entre ambos pensamientos suministra un argumento digno de tenerse en cuenta a favor de la innovadora concepción de la psique humana inaugurada por Carl Gustav Jung y desarrollada en esta línea por James Hillman.

  19. Bacteriophage therapy against Enterobacteriaceae

    Institute of Scientific and Technical Information of China (English)

    Youqiang; Xu; Yong; Liu; Yang; Liu; Jiangsen; Pei; Su; Yao; Chi; Cheng

    2015-01-01

    The Enterobacteriaceae are a class of gram-negative facultative anaerobic rods, which can cause a variety of diseases, such as bacteremia, septic arthritis, endocarditis, osteomyelitis, lower respiratory tract infections, skin and soft-tissue infections, urinary tract infections, intra-abdominal infections and ophthalmic infections, in humans, poultry, animals and fish. Disease caused by Enterobacteriaceae cause the deaths of millions of people every year, resulting in enormous economic loss. Drug treatment is a useful and efficient way to control Enterobacteriaceae infections. However, with the abuse of antibiotics, drug resistance has been found in growing number of Enterobacteriaceae infections and, as such, there is an urgent need to find new methods of control. Bacteriophage therapy is an efficient alternative to antibiotics as it employs a different antibacterial mechanism. This paper summarizes the history of bacteriophage therapy, its bacteriallytic mechanisms, and the studies that have focused on Enterobacteriaceae and bacteriophage therapy.

  20. Hyperexpansion of RNA Bacteriophage Diversity

    Science.gov (United States)

    Krishnamurthy, Siddharth R.; Janowski, Andrew B.; Zhao, Guoyan; Barouch, Dan; Wang, David

    2016-01-01

    Bacteriophage modulation of microbial populations impacts critical processes in ocean, soil, and animal ecosystems. However, the role of bacteriophages with RNA genomes (RNA bacteriophages) in these processes is poorly understood, in part because of the limited number of known RNA bacteriophage species. Here, we identify partial genome sequences of 122 RNA bacteriophage phylotypes that are highly divergent from each other and from previously described RNA bacteriophages. These novel RNA bacteriophage sequences were present in samples collected from a range of ecological niches worldwide, including invertebrates and extreme microbial sediment, demonstrating that they are more widely distributed than previously recognized. Genomic analyses of these novel bacteriophages yielded multiple novel genome organizations. Furthermore, one RNA bacteriophage was detected in the transcriptome of a pure culture of Streptomyces avermitilis, suggesting for the first time that the known tropism of RNA bacteriophages may include gram-positive bacteria. Finally, reverse transcription PCR (RT-PCR)-based screening for two specific RNA bacteriophages in stool samples from a longitudinal cohort of macaques suggested that they are generally acutely present rather than persistent. PMID:27010970

  1. Hyperexpansion of RNA Bacteriophage Diversity.

    Directory of Open Access Journals (Sweden)

    Siddharth R Krishnamurthy

    2016-03-01

    Full Text Available Bacteriophage modulation of microbial populations impacts critical processes in ocean, soil, and animal ecosystems. However, the role of bacteriophages with RNA genomes (RNA bacteriophages in these processes is poorly understood, in part because of the limited number of known RNA bacteriophage species. Here, we identify partial genome sequences of 122 RNA bacteriophage phylotypes that are highly divergent from each other and from previously described RNA bacteriophages. These novel RNA bacteriophage sequences were present in samples collected from a range of ecological niches worldwide, including invertebrates and extreme microbial sediment, demonstrating that they are more widely distributed than previously recognized. Genomic analyses of these novel bacteriophages yielded multiple novel genome organizations. Furthermore, one RNA bacteriophage was detected in the transcriptome of a pure culture of Streptomyces avermitilis, suggesting for the first time that the known tropism of RNA bacteriophages may include gram-positive bacteria. Finally, reverse transcription PCR (RT-PCR-based screening for two specific RNA bacteriophages in stool samples from a longitudinal cohort of macaques suggested that they are generally acutely present rather than persistent.

  2. Hyperexpansion of RNA Bacteriophage Diversity.

    Science.gov (United States)

    Krishnamurthy, Siddharth R; Janowski, Andrew B; Zhao, Guoyan; Barouch, Dan; Wang, David

    2016-03-01

    Bacteriophage modulation of microbial populations impacts critical processes in ocean, soil, and animal ecosystems. However, the role of bacteriophages with RNA genomes (RNA bacteriophages) in these processes is poorly understood, in part because of the limited number of known RNA bacteriophage species. Here, we identify partial genome sequences of 122 RNA bacteriophage phylotypes that are highly divergent from each other and from previously described RNA bacteriophages. These novel RNA bacteriophage sequences were present in samples collected from a range of ecological niches worldwide, including invertebrates and extreme microbial sediment, demonstrating that they are more widely distributed than previously recognized. Genomic analyses of these novel bacteriophages yielded multiple novel genome organizations. Furthermore, one RNA bacteriophage was detected in the transcriptome of a pure culture of Streptomyces avermitilis, suggesting for the first time that the known tropism of RNA bacteriophages may include gram-positive bacteria. Finally, reverse transcription PCR (RT-PCR)-based screening for two specific RNA bacteriophages in stool samples from a longitudinal cohort of macaques suggested that they are generally acutely present rather than persistent.

  3. Review of past experiments at the FELIX facility and future plans for ITER applications

    Energy Technology Data Exchange (ETDEWEB)

    Hua, T.Q.; Turner, L.R.

    1993-10-01

    FELIX is an experimental test facility at Argonne National Laboratory (ANL) for the study of electromagnetic effects in first wall, blanket, shield systems of fusion reactors. From 1983 to 1986 five major test series, including static and dynamic tests, were conducted and are reviewed in this paper. The dynamic tests demonstrated an important coupling effect between eddy currents and motion in a conducting structure. Recently the US has proposed to the ITER Joint Central Team to use FELIX for testing mock-up components to study electromagnetic effects encountered during plasma disruptions and other off-normal events. The near and long term plans for ITER applications are discussed.

  4. Chlamydial plasmids and bacteriophages.

    Science.gov (United States)

    Pawlikowska-Warych, Małgorzata; Śliwa-Dominiak, Joanna; Deptuła, Wiesław

    2015-01-01

    Chlamydia are absolute pathogens of humans and animals; despite being rather well recognised, they are still open for discovery. One such discovery is the occurrence of extrachromosomal carriers of genetic information. In prokaryotes, such carriers include plasmids and bacteriophages, which are present only among some Chlamydia species. Plasmids were found exclusively in Chlamydia (C.) trachomatis, C. psittaci, C. pneumoniae, C. suis, C. felis, C. muridarum and C. caviae. In prokaryotic organisms, plasmids usually code for genes that facilitate survival of the bacteria in the environment (although they are not essential). In chlamydia, their role has not been definitely recognised, apart from the fact that they participate in the synthesis of glycogen and encode proteins responsible for their virulence. Furthermore, in C. suis it was evidenced that the plasmid is integrated in a genomic island and contains the tetracycline-resistance gene. Bacteriophages specific for chlamydia (chlamydiaphages) were detected only in six species: C. psittaci, C. abortus, C. felis, C. caviae C. pecorum and C. pneumoniae. These chlamydiaphages cause inhibition of the developmental cycle, and delay transformation of reticulate bodies (RBs) into elementary bodies (EBs), thus reducing the possibility of infecting other cells in time. Plasmids and bacteriophages can be used in the diagnostics of chlamydioses; although especially in the case of plasmids, they are already used for detection of chlamydial infections. In addition, bacteriophages could be used as therapeutic agents to replace antibiotics, potentially addressing the problem of increasing antibiotic-resistance among chlamydia.

  5. Felix beyond the Closet: Sexuality, Masculinity, and Relations of Power in Arturo Islas's "The Rain God"

    Science.gov (United States)

    Padilla, Yolanda

    2009-01-01

    This essay examines the uneasy relationship that Arturo Islas's "The Rain God" has had with narratives of identity, focusing on how the representation of Felix's sexuality makes him a problematic figure for certain strains of Chicana/o and queer studies. In other writings, Islas criticizes Quinto Sol, the chief publishing house of Chicano…

  6. Governor Felix P. Camacho of Guam of the U.S. Visits China

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正>Felix P. Camacho, governor of Guam of the United States,and his party of 12 visited Beijing, Shanghai and Guangdong from September 25 to October 1, 2003 at the invitation of the CPAFFC. During their stay in China, Governor Camacho called on Chinese Foreign Minister Li Zhaoxing,

  7. FCJ-121 Transversalising the Ecological Turn: Four Components of Felix Guattari’s Ecosophical Perspective

    OpenAIRE

    John Tinnell

    2011-01-01

    Many humanities scholars are working to transform their disciplines in response to new conditions and problems emerging in the twenty-first century. Arguably, two of the most important forces affecting contemporary global culture are the growing awareness of the ecological crisis and the proliferation of digital media. This essay endeavors to develop Felix Guattari’s “unfinished” concept of ecosophy into a theoretical framework for constructing productive syntheses between the ecological an...

  8. Told by a myth: Thomas Mann’s Felix Krull

    OpenAIRE

    Montiel, Luis

    2013-01-01

    This article proposes an approach to the novel Bekenntnisse des Hochstaplers Felix Krull by Thomas Mann from the point of view of the imaginal psychology of James Hillman. From this perspective the novel seems to illustrate the most innovative thesis of that psychology, which is especially relevant for having been written prior to the formulation of Hillman’s theories. The unplanned correspondence between both ways of thinking furnishes a valuable argument that supports the new conception of ...

  9. FELIX: a High-Throughput Network Approach for Interfacing to Front End Electronics for ATLAS Upgrades

    CERN Document Server

    Anderson, John Thomas; The ATLAS collaboration; Boterenbrood, Hendrik; Chen, Hucheng; Chen, Kai; Drake, Gary; Francis, David; Gorini, Benedetto; Lanni, Francesco; Lehmann Miotto, Giovanna; Levinson, Lorne; Narevicius, Julia; Plessl, Christian; Roich, Alexander; Ryu, Soo; Schreuder, Frans Philip; Schumacher, Jorn; Vandelli, Wainer; Vermeulen, Jos; Zhang, Jinlong

    2015-01-01

    The ATLAS experiment at CERN is planning full deployment of a new unified optical link technology for connecting detector front end electronics on the timescale of the LHC Run 4 (2025). It is estimated that roughly 8000 GBT (GigaBit Transceiver) links, with transfer rates up to 10.24~Gbps, will replace existing links used for readout, detector control and distribution of timing and trigger information. A new class of devices will be needed to interface many GBT links to the rest of the trigger, data-acquisition and detector control systems. In this paper FELIX (Front End LInk eXchange) is presented, a PC-based device to route data from and to multiple GBT links via a high-performance general purpose network capable of a total throughput up to O(20 Tbps). FELIX implies architectural changes to the ATLAS data acquisition system, such as the use of industry standard COTS components early in the DAQ chain. Additionally the design and implementation of a FELIX demonstration platform is presented, and hardware and ...

  10. Bacteriophages as Therapeutic and Prophylactic Means: Summary of the Soviet and Post Soviet Experiences.

    Science.gov (United States)

    Chanishvili, Nina

    2016-01-01

    Bacteriophage (from 'bacteria' and Greek φαγεῖν phagein "to devour" or bacterial eaters) are bacterial viruses that infect and kill bacteria. Bacteriophages (shortly "phages") are among the most common and diverse entities in the biosphere. The estimated number of phages on earth is about 1032. Bacteriophages are often isolated from environmental sources, such as water samples, etc. Felix d'Herelle, one of the discoverers of bacteriophages, was the one who suggested them for therapy of human and animal bacterial infections. This idea was very popular in the world until the advent of antibiotics commercial after which production of therapeutic phages ceased in most of the Western countries, but not in the former Soviet Union. The application of antibiotics in the clinical practice, besides the well-known side effects, entails, in addition, the appearance of the forms of bacteria, resistant to newly synthesized preparations. It was concluded that a European and global strategy to address this gap is urgently needed. Now, faced with the alarming growth of a variety of antibiotic resistant bacterial infections, Western researchers and governments are giving phages a serious look. The phages nowadays are seen as a possible therapy against multi-drug-resistant strains of many bacteria. The therapeutic action of bacteriophages significantly differs from antibiotics, which makes them still active against multi-drug-resistant bacteria. Bacteriophages have a number of other advantages in comparison with antibiotics. First of all, they are efficient against multi-drug-resistant bacteria. The aim of this review was to provide an overview of the past and current experiences in the field of phage therapy in the countries where it has been traditionally applied in the clinical practice. Although the style and quality of old Soviet scientific publications dedicated to phage therapy are not challenging the international standards, there is still valuable information which

  11. Bacteriophages of methanotrophic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tyutikow, F.M. (All-Union Research Inst. for Genetics and Selection of Industrial Microorganisms, Moscow, USSR); Bespalova, I.A.; Rebentish, B.A.; Aleksandrushkina, N.N.; Krivisky, A.S.

    1980-10-01

    Bacteriophages of methanotrophic bacteria have been found in 16 out of 88 studied samples (underground waters, pond water, soil, gas and oil installation waters, fermentor cultural fluids, bacterial paste, and rumen of cattle) taken in different geographic zones of the Soviet Union. Altogether, 23 phage strains were isolated. By fine structure, the phages were divided into two types (with very short or long noncontractile tails); by host range and serological properties, they fell into three types. All phages had guanine- and cytosine-rich double-stranded deoxyribonucleic acid consisting of common nitrogen bases. By all of the above-mentioned properties, all phages within each of the groups were completely identical to one another, but differed from phages of other groups.

  12. Genetically modified bacteriophages.

    Science.gov (United States)

    Sagona, Antonia P; Grigonyte, Aurelija M; MacDonald, Paul R; Jaramillo, Alfonso

    2016-04-18

    Phages or bacteriophages, viruses that infect and replicate inside bacteria, are the most abundant microorganisms on earth. The realization that antibiotic resistance poses a substantial risk to the world's health and global economy is revitalizing phage therapy as a potential solution. The increasing ease by which phage genomes can be modified, owing to the influx of new technologies, has led to an expansion of their natural capabilities, and a reduced dependence on phage isolation from environmental sources. This review will discuss the way synthetic biology has accelerated the construction of genetically modified phages and will describe the wide range of their applications. It will further provide insight into the societal and economic benefits that derive from the use of recombinant phages in various sectors, from health to biodetection, biocontrol and the food industry.

  13. Genetically modified bacteriophages.

    Science.gov (United States)

    Sagona, Antonia P; Grigonyte, Aurelija M; MacDonald, Paul R; Jaramillo, Alfonso

    2016-04-18

    Phages or bacteriophages, viruses that infect and replicate inside bacteria, are the most abundant microorganisms on earth. The realization that antibiotic resistance poses a substantial risk to the world's health and global economy is revitalizing phage therapy as a potential solution. The increasing ease by which phage genomes can be modified, owing to the influx of new technologies, has led to an expansion of their natural capabilities, and a reduced dependence on phage isolation from environmental sources. This review will discuss the way synthetic biology has accelerated the construction of genetically modified phages and will describe the wide range of their applications. It will further provide insight into the societal and economic benefits that derive from the use of recombinant phages in various sectors, from health to biodetection, biocontrol and the food industry. PMID:26906932

  14. Governor Felix P. Camacho of Guam of the U.S. Visits China

    Institute of Scientific and Technical Information of China (English)

    ZhangHeqiang

    2004-01-01

    Felix E Camacho, governor of Guam of the United States,and his party of 12 visited Beijing,Shanghai and Guangdong from September 25 to October 1, 2003 at the invitation of the CPAFFC.During their stay in China, Governor Camacho called on Chinese Foreign Minister Li Zhaoxing,Chairman of China National Tourism Adrninistration He Guangwei and Shanghai Mayor Han Zheng,and held talks with the departments concerned. CPAFFC President Chen Haosu hosted a banquet to welcome the delegation. Governor Camacho gave a press briefing, granted interviews to reporters from CCTV-9 and TSTV, and attended the National Day reception held in the Great Hail of the People.

  15. FELIX experiments and computational needs for eddy current analysis of fusion reactors

    International Nuclear Information System (INIS)

    In a fusion reactor, changing magnetic fields are closely coupled to the electrically-conducting metal structure. This coupling is particularly pronounced in a tokamak reactor in which magnetic fields are used to confine, stabilize, drive, and heat the plasma. Electromagnetic effects in future fusion reactors will have far-reaching implications in the configuration, operation, and maintenance of the reactors. This paper describes the impact of eddy-current effects on future reactors, the requirements of computer codes for analyzing those effects, and the FELIX experiments which will provide needed data for code validation

  16. Radiation protection Aspects Using the Thermal Waters from the Felix-1 Mai-Oradea Geothermal Deposit

    International Nuclear Information System (INIS)

    Full text: The geothermal 'Felix-1 Mai-Oradea' deposit is situated in the western part of Romania and it is well known long years ago. The waters of this deposit are used in the medical treatments in the two resorts (Felix and 1 Mai) and for heating and swimming pools in Oradea town. The deposit depth (2500-3000 m) determines a high temperature (66-900 deg. C) of these waters also a mineral content of 200-1400 mg/l, the main components being Ca and Mg. First time, during some years, the thermal water was directly used in the central heating radiators from 'Nufarul' residential district. At present a heating switch installation is utilised. The high radium content of these thermal waters comparatively with Italian or Japanese thermal waters suggested us a study of radium deposition on the inner walls of the pipes also in the inner central heating radiators. Analysing these depositions using a high resolution Ge-Li detector, the radium-226 and small quantities of radium-224 and 223 isotopes were registered. Average radium-226 deposition was 1200 Bq/kg. (author)

  17. Review: Felix Heidenreich (2011: Theorien der Gerechtigkeit - Eine Einführung

    Directory of Open Access Journals (Sweden)

    Kramer, Hans-Ulrich

    2012-12-01

    Full Text Available Schon vor der griechischen Antike, nämlich bei den alten Ägyptern und im alten Israel ansetzend, werden unter dem Titel „Antike: Gegebene Gerechtigkeit“(Kapitel 2 anschließend die Theorien der griechischen Klassiker Platon und Aristoteles sowie des Römers Cicero behandelt. Weiter geht es in chronologischer, übersichtlicher Gliederung mit den zwei Gerechtigkeiten des Mittelalters (Kapitel 3, die auf der Zwei-Reiche-Lehre des Augustinus‘ aufbauen. Kapitel 4 steht unter dem Motto: „Neuzeit: Gerechtigkeit wird machbar“ undversammelt die Theorien von Machiavelli über Hobbes, Rousseau und Kant bis hin zu John Stuart Mill. In Kapitel 5 rekapituliertFelix Heidenreich dann Positionen in der aktuellen Debatte. Diese reichen unter anderem von dem sozialliberalen Denker John Rawls über die Kommunitaristen Alasdair MacIntyre und Michael Walzer bis hin zumdeutschen Philosophen und Diskursethiker Jürgen Habermas oder dem indischen Ökonomen Amartya Sen. In Kapitel 6 löst sich Felix Heidenreich schließlich von der personenbezogenen Auflistung und spricht von aktuellen Problemlagen der Gerechtigkeit, etwa der sozialen Gerechtigkeit, der Gerechtigkeit zwischen Frau und Mann oderauch der ökologischen und intergenerationellen Gerechtigkeit. Ein Ausblick zur Gerechtigkeitspolitik rundet den gut strukturierten,rund 250-seitigen Band ab.

  18. Virulence reduction in Bacteriophage resistant bacteria

    Directory of Open Access Journals (Sweden)

    Marcela eLeón

    2015-04-01

    Full Text Available Bacteriophages can influence the abundance, diversity and evolution of bacterial communities. Several bacteriophages have been reported to add virulence factors to their host and to increase bacterial virulence. However, lytic bacteriophages can also exert a selective pressure allowing the proliferation of strains with reduced virulence. This reduction can be explained because bacteriophages use structures present on the bacterial surface as receptors, which can be virulence factors in different bacterial species. Therefore, strains with modifications in these receptors will be resistant to bacteriophage infection and may also exhibit reduced virulence. This mini-review summarizes the reports on bacteriophage-resistant strains with reductions in virulence, and it discusses the potential consequences in phage therapy and in the use of bacteriophages to select attenuated strains for vaccines.

  19. Felion: a Cryogenic Ion Trap Apparatus for Spectroscopic Studies with Felix

    Science.gov (United States)

    Brunken, S.; Kluge, L.; Fanghanel, S.; Potapov, A.; Asvany, O.; Schlemmer, S.; Oomens, J.; Redlich, B.; Stoffels, A.

    2013-06-01

    The combination of ion trapping techniques with sensitive action spectroscopy schemes has been developed in recent years as a powerful tool to obtain spectra of gas-phase molecular ions from the UV to the (F)IR spectral regions. Here we report on the status of a specifically designed, dedicated cryogenic 22-pole ion trap apparatus (FELion), developed and built in Cologne, Germany, and intended to be installed permanently at the "Free-Electron Lasers for Infrared eXperiments" (FELIX) facility in Nijmegen, the Netherlands. This instrument will allow to record gas-phase IR and FIR spectra of mass-selected, internally cold molecular ions at temperatures in the range 4-300 K. By the use of diverse ionization methods, e.g. electron impact and electrospray ionization, a multitude of molecular ions can be generated and stored in the trap, including astrophysically relevant species ranging in size from the three-atomic H_3^+ up to large polycyclic aromatic hydrocarbon (PAH) ions, but also biomolecular ions like amino acids, peptides, or nucleobases. In combination with the powerful (F)IR radiation of the free electron lasers FELIX-1 and -2 (60-2500 cm^{-1}) and FLARE (6-100 cm^{-1}) at the FELIX facility, a variety of action spectroscopy schemes can be employed to study the ro-vibrational spectra of the stored ions, such as IR multiphoton dissociation, (F)IR/UV double resonance spectroscopy, or the method of laser induced reactions (LIR). In this talk we will give a detailed account of the experimental setup and present the first results obtained with the new apparatus. e.g., S. Schlemmer, E. Lescop, J. von Richthofen, D. Gerlich, and M. A. Smith, J. Chem. Phys. 117, 2068 (2002) J. Oomens, B. G. Sartakov, G. Meijer, and G. van Helden, Int. J. Mass Spectrom. 254, 1 (2006) T. R. Rizzo, J. A. Stearns, and O. V. Boyarkin, International Reviews in Physical Chemistry 28, 481 (2009) FLARE: Free-electron Laser for Advanced spectroscopy and high-Resolution Experiments

  20. Bacteriophages: back to the future

    Science.gov (United States)

    A Listeria monocytogenes-specific bacteriophage cocktail (ListShield™) was evaluated for its activity against a nalidixic acid-resistant L. monocytogenes (Lm-NalR) isolate on fresh-cut spinach stored under modified atmosphere packaging (MAP) at various temperatures. Pieces (~2x2 cm2) of fresh spinac...

  1. Bacteriophage endolysins as novel antimicrobials

    Science.gov (United States)

    Endolysins are enzymes used by bacteriophages at the end of their replication cycle to degrade the peptidoglycan of the bacterial host from within, resulting in cell lysis and release of progeny virions. Due to the absence of an outer membrane in the Gram-positive bacterial cell wall, endolysins can...

  2. Nanoscale bacteriophage biosensors beyond phage display

    Directory of Open Access Journals (Sweden)

    Lee JW

    2013-10-01

    Full Text Available Jong-Wook Lee,1 Jangwon Song,1,2 Mintai P Hwang,1 Kwan Hyi Lee1,2 1Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology, Seoul, Korea; 2Department of Biomedical Engineering, University of Science and Technology, Seoul, Korea Abstract: Bacteriophages are traditionally used for the development of phage display technology. Recently, their nanosized dimensions and ease with which genetic modifications can be made to their structure and function have put them in the spotlight towards their use in a variety of biosensors. In particular, the expression of any protein or peptide on the extraluminal surface of bacteriophages is possible by genetically engineering the genome. In addition, the relatively short replication time of bacteriophages offers researchers the ability to generate mass quantities of any given bacteriophage-based biosensor. Coupled with the emergence of various biomarkers in the clinic as a means to determine pathophysiological states, the development of current and novel technologies for their detection and quantification is imperative. In this review, we categorize bacteriophages by their morphology into M13-based filamentous bacteriophages and T4- or T7-based icosahedral bacteriophages, and examine how such advantages are utilized across a variety of biosensors. In essence, we take a comprehensive approach towards recent trends in bacteriophage-based biosensor applications and discuss their outlook with regards to the field of biotechnology. Keywords: biosensing, M13 bacteriophage, T4 bacteriophage, bacterial detection, Escherichia coli, SPR sensor

  3. Complete Genome Sequences of Five Bacteriophages That Infect Rhodobacter capsulatus.

    Science.gov (United States)

    Bollivar, David W; Bernardoni, Brooke; Bockman, Matthew R; Miller, Brenda M; Russell, Daniel A; Delesalle, Veronique A; Krukonis, Gregory P; Hatfull, Graham F; Cross, Madeline R; Szewczyk, Marlena M; Eppurath, Atul

    2016-05-26

    Five bacteriophages that infect the Rhodobacter capsulatus strain YW1 were isolated from stream water near Bloomington, Illinois, USA. Two distinct genome types are represented in the newly isolated bacteriophages. These genomes are different from other bacteriophage genomes previously described.

  4. The science and politics of forest management in Northern Nicaragua after hurricane Felix (2007)

    Science.gov (United States)

    Rossi Idarraga, Esteban

    This dissertation examines the ecological effects of hurricane Felix (2007) in Northern Nicaragua as well as the socio-political factors that influenced forest management efforts in hurricane impacted locations. Specifically, this research focused on the following questions: first, what were the regional damage patterns caused by hurricane Felix on the forests of Northern Nicaragua? Second, what stand and tree attributes explain observed post-hurricane damage patterns? And, third, why were post-hurricane management efforts unsuccessful? The first dissertation article characterizes the intensity and spatial distribution of forest damage after hurricane Felix using satellite imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor and aerial photographs. Results indicated that Broadleaf forests experienced larger damage (>75% trees blown down) than Pine forest, and that Enhanced Vegetation Index data (EVI), obtained from the MODIS sensor, can adequately depict post-hurricane damage in tropical forests. The agreement between the obtained EVI damage map and the reference data set ranged from 91% in high-damage locations to 85% in low-damage locations, with 86% overall agreement. The second dissertation article describes the relationship between hurricane damage patterns and ecological variables at the local level. Specifically, it characterizes the relationship between tree-and-stand attributes (i.e. DBH, height, density, basal area) and wind damage, using field data. Findings indicate that tree attributes such as DBH and height strongly influenced the amount and type of wind damage and that stand attributes such as maximum canopy height and distance to the hurricane path were also predictive of the amount of damage. Observed differences in damage patterns among broadleaf and pine forests were strongly correlated with the height to diameter ratio (H/D). Field observations showed that while post-hurricane regeneration was abundant in broadleaf

  5. Bacteriophage Procurement for Therapeutic Purposes.

    Science.gov (United States)

    Weber-Dąbrowska, Beata; Jończyk-Matysiak, Ewa; Żaczek, Maciej; Łobocka, Małgorzata; Łusiak-Szelachowska, Marzanna; Górski, Andrzej

    2016-01-01

    Bacteriophages (phages), discovered 100 years ago, are able to infect and destroy only bacterial cells. In the current crisis of antibiotic efficacy, phage therapy is considered as a supplementary or even alternative therapeutic approach. Evolution of multidrug-resistant and pandrug-resistant bacterial strains poses a real threat, so it is extremely important to have the possibility to isolate new phages for therapeutic purposes. Our phage laboratory and therapy center has extensive experience with phage isolation, characterization, and therapeutic application. In this article we present current progress in bacteriophages isolation and use for therapeutic purposes, our experience in this field and its practical implications for phage therapy. We attempt to summarize the state of the art: properties of phages, the methods for their isolation, criteria of phage selection for therapeutic purposes and limitations of their use. Perspectives for the use of genetically engineered phages to specifically target bacterial virulence-associated genes are also briefly presented. PMID:27570518

  6. Bacteriophage biocontrol of foodborne pathogens.

    Science.gov (United States)

    Kazi, Mustafa; Annapure, Uday S

    2016-03-01

    Bacteriophages are viruses that only infect bacterial cells. Phages are categorized based on the type of their life cycle, the lytic cycle cause lysis of the bacterium with the release of multiple phage particles where as in lysogenic phase the phage DNA is incorporated into the bacterial genome. Lysogeny does not result in lysis of the host. Lytic phages have several potential applications in the food industry as biocontrol agents, biopreservatives and as tools for detecting pathogens. They have also been proposed as alternatives to antibiotics in animal health. Two unique features of phage relevant for food safety are that they are harmless to mammalian cells and high host specificity, keeping the natural microbiota undisturbed. However, the recent approval of bacteriophages as food additives has opened the discussion about 'edible viruses'. This article reviews in detail the application of phages for the control of foodborne pathogens in a process known as "biocontrol". PMID:27570260

  7. When viruses were not in style: parallels in the histories of chicken sarcoma viruses and bacteriophages.

    Science.gov (United States)

    Sankaran, Neeraja

    2014-12-01

    The discovery that cancer may be caused by viruses occurred in the early twentieth century, a time when the very concept of viruses as we understand it today was in a considerable state of flux. Although certain features were agreed upon, viruses, more commonly referred to as 'filterable viruses' were not considered much different from other microbes such as bacteria except for their extremely small size, which rendered them ultramicroscopic and filterable. For a long time, in fact, viruses were defined rather by what they were not and what they could not do, rather than any known properties that set them apart from other microbes. Consequently when Peyton Rous suggested in 1912 that the causative agent of a transmissible sarcoma tumor of chickens was a virus, the medical research community was reluctant to accept his assessment on the grounds that cancer was not infectious and was caused by a physiological change within the cells. This difference in the bacteriological and physiological styles of thinking appears to have been prevalent in the wider research community, for when in 1917 Felix d'Herelle suggested that a transmissible lysis in bacteria, which he called bacteriophagy, was caused by a virus, his ideas were also opposed on similar grounds. It was not until the 1950s when when André Lwoff explained the phenomenon of lysogeny through his prophage hypothesis that the viral identities of the sarcoma-inducing agent and the bacteriophages were accepted. This paper examines the trajectories of the curiously parallel histories of the cancer viruses and highlights the similarities and differences between the ways in which prevailing ideas about the nature of viruses, heredity and infection drove researchers from disparate disciplines and geographic locations to develop their ideas and achieve some consensus about the nature of cancer viruses and bacteriophages.

  8. Use of Bacteriophages to control bacterial pathogens

    Science.gov (United States)

    Lytic bacteriophages can provide a natural method and an effective alternative to antibiotics to reduce bacterial pathogens in animals, foods, and other environments. Bacteriophages (phages) are viruses which infect bacterial cells and eventually kill them through lysis, and represent the most abun...

  9. Programming Bacteriophages by Swapping Their Specificity Determinants.

    Science.gov (United States)

    Goren, Moran G; Yosef, Ido; Qimron, Udi

    2015-12-01

    Bacteriophages, bacteria's natural enemies, may serve as potent antibacterial agents. Their specificity for certain bacterial sub-species limits their effectiveness, but allows selective targeting of bacteria. Lu and colleagues present a platform for such targeting through alteration of bacteriophages' host specificity by swapping specificity domains in their host-recognition ligand.

  10. Nanoscale bacteriophage biosensors beyond phage display.

    Science.gov (United States)

    Lee, Jong-Wook; Song, Jangwon; Hwang, Mintai P; Lee, Kwan Hyi

    2013-01-01

    Bacteriophages are traditionally used for the development of phage display technology. Recently, their nanosized dimensions and ease with which genetic modifications can be made to their structure and function have put them in the spotlight towards their use in a variety of biosensors. In particular, the expression of any protein or peptide on the extraluminal surface of bacteriophages is possible by genetically engineering the genome. In addition, the relatively short replication time of bacteriophages offers researchers the ability to generate mass quantities of any given bacteriophage-based biosensor. Coupled with the emergence of various biomarkers in the clinic as a means to determine pathophysiological states, the development of current and novel technologies for their detection and quantification is imperative. In this review, we categorize bacteriophages by their morphology into M13-based filamentous bacteriophages and T4- or T7-based icosahedral bacteriophages, and examine how such advantages are utilized across a variety of biosensors. In essence, we take a comprehensive approach towards recent trends in bacteriophage-based biosensor applications and discuss their outlook with regards to the field of biotechnology.

  11. Felix: A Topology based Framework for Visual Exploration of Cosmic Filaments

    CERN Document Server

    Shivshankar, Nithin; Natarajan, Vijay; van de Weygaert, Rien; Bos, E G Patrick; Rieder, Steven

    2015-01-01

    The large-scale structure of the universe is comprised of virialized blob-like clusters, linear filaments, sheet-like walls and huge near empty three-dimensional voids. Characterizing the large scale universe is essential to our understanding of the formation and evolution of galaxies. The density range of clusters, walls and voids are relatively well separated, when compared to filaments, which span a relatively larger range. The large scale filamentary network thus forms an intricate part of the cosmic web. In this paper, we describe Felix, a topology based framework for visual exploration of filaments in the cosmic web. The filamentary structure is represented by the ascending manifold geometry of the 2-saddles in the Morse-Smale complex of the density field. We generate a hierarchy of Morse-Smale complexes and query for filaments based on the density ranges at the end points of the filaments. The query is processed efficiently over the entire hierarchical Morse-Smale complex, allowing for interactive visu...

  12. FCJ-121 Transversalising the Ecological Turn: Four Components of Felix Guattari’s Ecosophical Perspective

    Directory of Open Access Journals (Sweden)

    John Tinnell

    2011-10-01

    Full Text Available Many humanities scholars are working to transform their disciplines in response to new conditions and problems emerging in the twenty-first century. Arguably, two of the most important forces affecting contemporary global culture are the growing awareness of the ecological crisis and the proliferation of digital media. This essay endeavors to develop Felix Guattari’s “unfinished” concept of ecosophy into a theoretical framework for constructing productive syntheses between the ecological and the digital. In general, the essay first articulates ecosophical models of individual and collective subjectivity, and then argues that the best way to sustain ecosophical identity experience is to invent “post-media” practices, which harness the networked infrastructure of digital media such that specific pedagogical engagements with the technology effectively maximise the user’s capacity to affect and be affected by immanent forces in the world. In addition, this Guattarian rethinking of the ecological turn concurrently challenges the philosophical basis of the pedagogy of Nature appreciation that has characterised the eco-humanities landscape since the 1970s. The essay’s conclusions gesture toward a transversal eco-humanities, which would be rhizomatically rooted in Guattari’s preference for autopoiesis and becoming-other (via new media, rather than a static allegiance to the ideals of “Self-realisation” postulated by the deep ecology movement.

  13. [Felix Mendelssohn Bartholdy (1809 - 1847): the mystery of his early death].

    Science.gov (United States)

    Schmideler, S; Somburg, O; Steinberg, H; Splett, T

    2006-09-01

    Composer and director of music at Leipzig's Gewandhaus Felix Mendelssohn Bartholdy died remarkably young, on 4 November 1847, at the age of 38. The cause of his early death has been a mystery ever since. Three contemporary doctors diagnosed Nervenschlag ("nervous stroke"). Starting with a short outline of Mendelssohn's pathography, this paper includes and quotes for the first time all the contemporary accounts of his death. After considering the older medical interpretations, the paper considers these reports from the point of view of present-day neurological and psychiatric expertise. It reveals that all the accounts had been filed by medical laymen, so their personal impressions had played a major role in their reports. However, it is indisputable that it was pathologic brain alterations that lead to Mendelssohn's death. Weighing up and carefully considering the sources, the authors regard subarachnoidal hemorrhage (SAH) as a likely cause of death. There may even have been some kind of genetic predisposition, since what is reported in this paper regarding Mendelssohn's death also applies to the very similar symptoms and circumstances surrounding his sister Fanny's death.

  14. Rb-Sr geochronology from Sao Felix to Xingu: preliminary results

    International Nuclear Information System (INIS)

    Rb-Sr systematics have been applied on rocks from the Sao Felix do Xingu region, in the southeastern part of the State of Para. An age of 2716 ± 34 Ma with IR of 0.70292 ± 0.00030 (MSWD = 1.54) and an age of 2677 ± 50 Ma with IR of 0.70161 ± 0.00022 (MSWD = 5.21) had been obtained for a granitic body and a tonalitic body respectively, both of them associated to the green stones belts that occur in this area. Gneisses from the Xingu complex gave an age of 2574 ± 57 Ma with an IR of 0.70416 ± 0.00054 (MSWD = 5.06). An age of 1653 ± 14 Ma with IR of 0.70823 ± 0.02361 (MSWD = 1.71) had been obtained for the Velho Guilherme granite that crosscut the granite-green stones terrains. Such geochronological data show the existence of a magmatic event between 2.72 Ga and 2.68 Ga and permit us to conclude on the archaean age of the green stones terrains. (author)

  15. Two bacteriophages of Clostridium difficile.

    OpenAIRE

    Mahony, D E; Bell, P D; Easterbrook, K. B.

    1985-01-01

    Two temperate bacteriophages of differing morphology and host range were isolated by screening 94 isolates of Clostridium difficile. Phage 41 had a 300-nm flexible tail, whereas phage 56 had a shorter tail with a contractile sheath. Electron microscopy of phage 56 lysates exposed to elevated magnesium concentrations showed small virus-like particles which were 21 nm in diameter. The addition of MgCl2 to semisolid agar overlays enhanced both the titer and plaque size of phage 56. Phage 56 was ...

  16. Propagating the missing bacteriophages: a large bacteriophage in a new class

    Directory of Open Access Journals (Sweden)

    Hardies Stephen C

    2007-02-01

    Full Text Available Abstract The number of successful propagations/isolations of soil-borne bacteriophages is small in comparison to the number of bacteriophages observed by microscopy (great plaque count anomaly. As one resolution of the great plaque count anomaly, we use propagation in ultra-dilute agarose gels to isolate a Bacillus thuringiensis bacteriophage with a large head (95 nm in diameter, tail (486 × 26 nm, corkscrew-like tail fibers (187 × 10 nm and genome (221 Kb that cannot be detected by the usual procedures of microbiology. This new bacteriophage, called 0305φ8-36 (first number is month/year of isolation; remaining two numbers identify the host and bacteriophage, has a high dependence of plaque size on the concentration of a supporting agarose gel. Bacteriophage 0305φ8-36 does not propagate in the traditional gels used for bacteriophage plaque formation and also does not produce visible lysis of liquid cultures. Bacteriophage 0305φ8-36 aggregates and, during de novo isolation from the environment, is likely to be invisible to procedures of physical detection that use either filtration or centrifugal pelleting to remove bacteria. Bacteriophage 0305φ8-36 is in a new genomic class, based on genes for both structural components and DNA packaging ATPase. Thus, knowledge of environmental virus diversity is expanded with prospect of greater future expansion.

  17. Immunocompatibility of Bacteriophages as Nanomedicines

    Directory of Open Access Journals (Sweden)

    Tranum Kaur

    2012-01-01

    Full Text Available Bacteriophage-based medical research provides the opportunity to develop targeted nanomedicines with heightened efficiency and safety profiles. Filamentous phages also can and have been formulated as targeted drug-delivery nanomedicines, and phage may also serve as promising alternatives/complements to antibiotics. Over the past decade the use of phage for both the prophylaxis and the treatment of bacterial infection, has gained special significance in view of a dramatic rise in the prevalence of antibiotic resistance bacterial strains. Two potential medical applications of phages are the treatment of bacterial infections and their use as immunizing agents in diagnosis and monitoring patients with immunodeficiencies. Recently, phages have been employed as gene-delivery vectors (phage nanomedicine, for nearly half a century as tools in genetic research, for about two decades as tools for the discovery of specific target-binding proteins and peptides, and for almost a decade as tools for vaccine development. As phage applications to human therapeutic development grow at an exponential rate, it will become essential to evaluate host immune responses to initial and repetitive challenges by therapeutic phage in order to develop phage therapies that offer suitable utility. This paper examines and discusses phage nanomedicine applications and the immunomodulatory effects of bacteriophage exposure and treatment modalities.

  18. FELIX: a PCIe based high-throughput approach for interfacing front-end and trigger electronics in the ATLAS Upgrade framework

    CERN Document Server

    Anderson, John Thomas; The ATLAS collaboration

    2016-01-01

    The ATLAS Phase-I upgrade (2018) requires a Trigger and Data Acquisition (TDAQ) system able to trigger and record data from up to three times the nominal LHC instantaneous luminosity. The Front-End LInk eXchange (FELIX) system provides an infrastructure to achieve this in a scalable, detector agnostic and easily upgradeable way. It is a PC-based gateway, interfacing custom radiation tolerant optical links from front-end electronics, via FPGA PCIe Gen3 cards, to a commodity switched Ethernet or InfiniBand network. FELIX enables reducing custom electronics in favour of software running on commercial servers. The FELIX system, the design of the PCIe prototype card and the integration test results are presented in this paper.

  19. FELIX-1.0: A finite element solver for the time dependent generator coordinate method with the Gaussian overlap approximation

    Energy Technology Data Exchange (ETDEWEB)

    Regnier, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); CEA, DAM, DIF, Arpajon (France); Verriere, M. [CEA, DAM, DIF, Arpajon (France); Dubray, N. [CEA, DAM, DIF, Arpajon (France); Schunck, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-11-30

    In this study, we describe the software package FELIX that solves the equations of the time-dependent generator coordinate method (TDGCM) in NN-dimensions (N ≥ 1) under the Gaussian overlap approximation. The numerical resolution is based on the Galerkin finite element discretization of the collective space and the Crank–Nicolson scheme for time integration. The TDGCM solver is implemented entirely in C++. Several additional tools written in C++, Python or bash scripting language are also included for convenience. In this paper, the solver is tested with a series of benchmarks calculations. We also demonstrate the ability of our code to handle a realistic calculation of fission dynamics.

  20. FELIX-1.0: A finite element solver for the time dependent generator coordinate method with the Gaussian overlap approximation

    Science.gov (United States)

    Regnier, D.; Verrière, M.; Dubray, N.; Schunck, N.

    2016-03-01

    We describe the software package FELIX that solves the equations of the time-dependent generator coordinate method (TDGCM) in N-dimensions (N ≥ 1) under the Gaussian overlap approximation. The numerical resolution is based on the Galerkin finite element discretization of the collective space and the Crank-Nicolson scheme for time integration. The TDGCM solver is implemented entirely in C++. Several additional tools written in C++, Python or bash scripting language are also included for convenience. In this paper, the solver is tested with a series of benchmarks calculations. We also demonstrate the ability of our code to handle a realistic calculation of fission dynamics.

  1. FELIX-1.0: A finite element solver for the time dependent generator coordinate method with the Gaussian overlap approximation

    CERN Document Server

    Regnier, D; Dubray, N; Schunck, N

    2015-01-01

    We describe the software package FELIX that solves the equations of the time-dependent generator coordinate method (TDGCM) in N-dimensions (N $\\geq$ 1) under the Gaussian overlap approximation. The numerical resolution is based on the Galerkin finite element discretization of the collective space and the Crank-Nicolson scheme for time integration. The TDGCM solver is implemented entirely in C++. Several additional tools written in C++, Python or bash scripting language are also included for convenience. In this paper, the solver is tested with a series of benchmarks calculations. We also demonstrate the ability of our code to handle a realistic calculation of fission dynamics.

  2. Bacteriophages of Leuconostoc, Oenococcus, and Weissella

    DEFF Research Database (Denmark)

    Kot, Witold; Neve, Horst; Heller, Knut J;

    2014-01-01

    can be classified as either Ln. mesenteroides or Ln. pseudomesenteroides. They are important flavor producers in dairy fermentations and they initiate nearly all vegetable fermentations. Therefore, bacteriophages attacking Leuconostoc strains may negatively influence the production process....... Bacteriophages attacking Leuconostoc strains were first reported in 1946. Since then, the majority of described Leuconostoc phages was isolated from either dairy products or fermented vegetable products. Both lytic and temperate phages of Leuconostoc were reported. Most of Leuconostoc phages examined using...

  3. Evidence of a dominant lineage of Vibrio cholerae-specific lytic bacteriophages shed by cholera patients over a 10-year period in Dhaka, Bangladesh.

    Science.gov (United States)

    Seed, Kimberley D; Bodi, Kip L; Kropinski, Andrew M; Ackermann, Hans-Wolfgang; Calderwood, Stephen B; Qadri, Firdausi; Camilli, Andrew

    2011-01-01

    Lytic bacteriophages are hypothesized to contribute to the seasonality and duration of cholera epidemics in Bangladesh. However, the bacteriophages contributing to this phenomenon have yet to be characterized at a molecular genetic level. In this study, we isolated and sequenced the genomes of 15 bacteriophages from stool samples from cholera patients spanning a 10-year surveillance period in Dhaka, Bangladesh. Our results indicate that a single novel bacteriophage type, designated ICP1 (for the International Centre for Diarrhoeal Disease Research, Bangladesh cholera phage 1) is present in all stool samples from cholera patients, while two other bacteriophage types, one novel (ICP2) and one T7-like (ICP3), are transient. ICP1 is a member of the Myoviridae family and has a 126-kilobase genome comprising 230 open reading frames. Comparative sequence analysis of ICP1 and related isolates from this time period indicates a high level of genetic conservation. The ubiquitous presence of ICP1 in cholera patients and the finding that the O1 antigen of lipopolysaccharide (LPS) serves as the ICP1 receptor suggest that ICP1 is extremely well adapted to predation of human-pathogenic V. cholerae O1.

  4. Characterization and purification of bacteriophages using chromatofocusing.

    Science.gov (United States)

    Brorson, Kurt; Shen, Hong; Lute, Scott; Pérez, Jessica Soto; Frey, Douglas D

    2008-10-17

    The technique of chromatofocusing was applied to the characterization and purification of three bacteriophages that are routinely used for testing virus filters: phiX174, PR772, and PP7. Chemically well-defined eluent buffers were used, instead of the more commonly used chromatofocusing polyampholyte buffers. Chromatographic column packings were selected to minimize band broadening by confining bacteriophage adsorption solely to the exterior particle surface. Under the conditions used it was determined that bacteriophages could be made to focus into narrow bands in a retained pH gradient with recoveries of live phage that ranged from 15 to nearly 100% as determined by a plaque-forming assay. Retention times and apparent isoelectric point data were obtained for samples consisting either of purified bacteriophage, or samples consisting of crude preparations of bacteriophages containing host cell impurities. Isoelectric point estimates were obtained using modified, previously described models. The results obtained suggest that chromatofocusing is a simple and rapid method for obtaining approximate isoelectric points for bacteriophages and probably other types of viruses. It is also likely a useful method for purifying these materials.

  5. Pathogen detection using engineered bacteriophages.

    Science.gov (United States)

    Smartt, Abby E; Xu, Tingting; Jegier, Patricia; Carswell, Jessica J; Blount, Samuel A; Sayler, Gary S; Ripp, Steven

    2012-04-01

    Bacteriophages, or phages, are bacterial viruses that can infect a broad or narrow range of host organisms. Knowing the host range of a phage allows it to be exploited in targeting various pathogens. Applying phages for the identification of microorganisms related to food and waterborne pathogens and pathogens of clinical significance to humans and animals has a long history, and there has to some extent been a recent revival in these applications as phages have become more extensively integrated into novel detection, identification, and monitoring technologies. Biotechnological and genetic engineering strategies applied to phages are responsible for some of these new methods, but even natural unmodified phages are widely applicable when paired with appropriate innovative detector platforms. This review highlights the use of phages as pathogen detector interfaces to provide the reader with an up-to-date inventory of phage-based biodetection strategies.

  6. Host receptors for bacteriophage adsorption.

    Science.gov (United States)

    Bertozzi Silva, Juliano; Storms, Zachary; Sauvageau, Dominic

    2016-02-01

    The adsorption of bacteriophages (phages) onto host cells is, in all but a few rare cases, a sine qua non condition for the onset of the infection process. Understanding the mechanisms involved and the factors affecting it is, thus, crucial for the investigation of host-phage interactions. This review provides a survey of the phage host receptors involved in recognition and adsorption and their interactions during attachment. Comprehension of the whole infection process, starting with the adsorption step, can enable and accelerate our understanding of phage ecology and the development of phage-based technologies. To assist in this effort, we have established an open-access resource--the Phage Receptor Database (PhReD)--to serve as a repository for information on known and newly identified phage receptors. PMID:26755501

  7. Genesis of Pre-Hurricane Felix (2007). Part 2; Warm Core Formation, Precipitation Evolution, and Predictability

    Science.gov (United States)

    Wang, zhuo; Montgomery M. T.; Dunkerton, T. J.

    2010-01-01

    This is the second of a two-part study examining the simulated formation of Atlantic Hurricane Felix (2007) in a cloud-representing framework. Here several open issues are addressed concerning the formation of the storm's warm core, the evolution and respective contribution of stratiform versus convective precipitation within the parent wave's pouch, and the sensitivity of the development pathway reported in Part I to different model physics options and initial conditions. All but one of the experiments include ice microphysics as represented by one of several parameterizations, and the partition of convective versus stratiform precipitation is accomplished using a standard numerical technique based on the high-resolution control experiment. The transition to a warm-core tropical cyclone from an initially cold-core, lower tropospheric wave disturbance is analyzed first. As part of this transformation process, it is shown that deep moist convection is sustained near the pouch center. Both convective and stratiform precipitation rates increase with time. While stratiform precipitation occupies a larger area even at the tropical storm stage, deep moist convection makes a comparable contribution to the total rain rate at the pregenesis stage, and a larger contribution than stratiform processes at the storm stage. The convergence profile averaged near the pouch center is found to become dominantly convective with increasing deep moist convective activity there. Low-level convergence forced by interior diabatic heating plays a key role in forming and intensifying the near-surface closed circulation, while the midlevel convergence associated with stratiform precipitation helps to increase the midlevel circulation and thereby contributes to the formation and upward extension of a tropospheric-deep cyclonic vortex. Sensitivity tests with different model physics options and initial conditions demonstrate a similar pregenesis evolution. These tests suggest that the genesis

  8. Complete Genome Sequence of Bacillus thuringiensis Bacteriophage BMBtp2

    OpenAIRE

    Dong, Zhaoxia; Peng, Donghai; Wang, Yueying; Zhu, Lei; Ruan, Lifang; Sun, Ming

    2013-01-01

    Bacillus thuringiensis is an insect pathogen which has been widely used for biocontrol. During B. thuringiensis fermentation, lysogenic bacteriophages cause severe losses of yield. Here, we announce the complete genome sequence of a bacteriophage, BMBtp2, which is induced from B. thuringiensis strain YBT-1765, which may be helpful to clarify the mechanism involved in bacteriophage contamination.

  9. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Staphylococcal typing bacteriophage. (a) Identification. A staphylococcal typing bacteriophage is a...

  10. Bacteriophage-Based Pathogen Detection

    Science.gov (United States)

    Ripp, Steven

    Considered the most abundant organism on Earth, at a population approaching 1031, bacteriophage, or phage for short, mediate interactions with myriad bacterial hosts that has for decades been exploited in phage typing schemes for signature identification of clinical, food-borne, and water-borne pathogens. With over 5,000 phage being morphologically characterized and grouped as to susceptible host, there exists an enormous cache of bacterial-specific sensors that has more recently been incorporated into novel bio-recognition assays with heightened sensitivity, specificity, and speed. These assays take many forms, ranging from straightforward visualization of labeled phage as they attach to their specific bacterial hosts to reporter phage that genetically deposit trackable signals within their bacterial hosts to the detection of progeny phage or other uniquely identifiable elements released from infected host cells. A comprehensive review of these and other phage-based detection assays, as directed towards the detection and monitoring of bacterial pathogens, will be provided in this chapter.

  11. Photodynamic Inactivation of Mammalian Viruses and Bacteriophages

    Directory of Open Access Journals (Sweden)

    Liliana Costa

    2012-06-01

    Full Text Available Photodynamic inactivation (PDI has been used to inactivate microorganisms through the use of photosensitizers. The inactivation of mammalian viruses and bacteriophages by photosensitization has been applied with success since the first decades of the last century. Due to the fact that mammalian viruses are known to pose a threat to public health and that bacteriophages are frequently used as models of mammalian viruses, it is important to know and understand the mechanisms and photodynamic procedures involved in their photoinactivation. The aim of this review is to (i summarize the main approaches developed until now for the photodynamic inactivation of bacteriophages and mammalian viruses and, (ii discuss and compare the present state of the art of mammalian viruses PDI with phage photoinactivation, with special focus on the most relevant mechanisms, molecular targets and factors affecting the viral inactivation process.

  12. Photodynamic inactivation of mammalian viruses and bacteriophages.

    Science.gov (United States)

    Costa, Liliana; Faustino, Maria Amparo F; Neves, Maria Graça P M S; Cunha, Angela; Almeida, Adelaide

    2012-07-01

    Photodynamic inactivation (PDI) has been used to inactivate microorganisms through the use of photosensitizers. The inactivation of mammalian viruses and bacteriophages by photosensitization has been applied with success since the first decades of the last century. Due to the fact that mammalian viruses are known to pose a threat to public health and that bacteriophages are frequently used as models of mammalian viruses, it is important to know and understand the mechanisms and photodynamic procedures involved in their photoinactivation. The aim of this review is to (i) summarize the main approaches developed until now for the photodynamic inactivation of bacteriophages and mammalian viruses and, (ii) discuss and compare the present state of the art of mammalian viruses PDI with phage photoinactivation, with special focus on the most relevant mechanisms, molecular targets and factors affecting the viral inactivation process.

  13. Antiviral effect of cationic compounds on bacteriophages

    Directory of Open Access Journals (Sweden)

    Mai Huong eChatain-Ly

    2013-03-01

    Full Text Available The antiviral activity of several cationic compounds - cetytrimethylammonium (CTAB, chitosan, nisin and lysozyme - was investigated on the bacteriophage c2 (DNA head and non-contractile tail infecting Lactococcus strains and the bacteriophage MS2 (F-specific RNA infecting E.coli. Firstly, these activities were evaluated in a phosphate buffer pH 7- 10 mM. The CTAB had a virucidal effect on the Lactococcus bacteriophages, but not on the MS2. After 1 min of contact with 0.125 mM CTAB, the c2 population was reduced from 6 log(pfu/mL to 1,5 log(pfu/mL and completely deactivated at 1 mM. On the contrary, chitosan inhibited the MS2 more than it did the bacteriophages c2. No antiviral effect was observed for the nisin or the lysozyme on bacteriophages after 1 min of treatment. A 1 and 2.5 log reduction was respectively observed for nisin and lysozyme when the treatment time increased (5 or 10 min. These results showed that the antiviral effect depended both on the virus and structure of the antimicrobial compounds. The antiviral activity of these compounds was also evaluated in different physico-chemical conditions and in complex matrices. The antiviral activity of CTAB was impaired in acid pH and with an increase of the ionic strength. These results might be explained by the electrostatic interactions between cationic compounds and negatively charged particles such as bacteriophages or other compounds in a matrix. Milk proved to be protective suggesting the components of food could interfere with antimicrobial compounds.

  14. A stochastic model for bacteriophage therapies

    CERN Document Server

    Bardina, Xavier; Rovira, Carles; Tindel, Samy

    2011-01-01

    In this article, we analyze a system modeling bacteriophage treatments for infections in a noisy context. In the small noise regime, we show that after a reasonable amount of time the system is close to a sane equilibrium (which is a relevant biologic information) with high probability. Mathematically speaking, our study hinges on concentration techniques for delayed stochastic differential equations.

  15. Bacteriophages as surface and ground water tracers

    Directory of Open Access Journals (Sweden)

    P. Rossi

    1998-01-01

    Full Text Available Bacteriophages are increasingly used as tracers for quantitative analysis in both hydrology and hydrogeology. The biological particles are neither toxic nor pathogenic for other living organisms as they penetrate only a specific bacterial host. They have many advantages over classical fluorescent tracers and offer the additional possibility of multi-point injection for tracer tests. Several years of research make them suitable for quantitative transport analysis and flow boundary delineation in both surface and ground waters, including karst, fractured and porous media aquifers. This article presents the effective application of bacteriophages based on their use in differing Swiss hydrological environments and compares their behaviour to conventional coloured dye or salt-type tracers. In surface water and karst aquifers, bacteriophages travel at about the same speed as the typically referenced fluorescent tracers (uranine, sulphurhodamine G extra. In aquifers of interstitial porosity, however, they appear to migrate more rapidly than fluorescent tracers, albeit with a significant reduction in their numbers within the porous media. This faster travel time implies that a modified rationale is needed for defining some ground water protection area boundaries. Further developments of other bacteriophages and their documentation as tracer methods should result in an accurate and efficient tracer tool that will be a proven alternative to conventional fluorescent dyes.

  16. ADSORPTION OF BACTERIOPHAGES ON CLAY MINERALS

    Science.gov (United States)

    Theability to predict the fate of microorganisms in soil is dependent on an understanding of the process of their sorption on soil and subsurface materials. Presently, we have focused on studying the thermodynamics of sorption of bacteriophages (T-2, MS-2, and

  17. Comparative genomics of Shiga toxin encoding bacteriophages

    Directory of Open Access Journals (Sweden)

    Smith Darren L

    2012-07-01

    Full Text Available Abstract Background Stx bacteriophages are responsible for driving the dissemination of Stx toxin genes (stx across their bacterial host range. Lysogens carrying Stx phages can cause severe, life-threatening disease and Stx toxin is an integral virulence factor. The Stx-bacteriophage vB_EcoP-24B, commonly referred to as Ф24B, is capable of multiply infecting a single bacterial host cell at a high frequency, with secondary infection increasing the rate at which subsequent bacteriophage infections can occur. This is biologically unusual, therefore determining the genomic content and context of Ф24B compared to other lambdoid Stx phages is important to understanding the factors controlling this phenomenon and determining whether they occur in other Stx phages. Results The genome of the Stx2 encoding phage, Ф24B was sequenced and annotated. The genomic organisation and general features are similar to other sequenced Stx bacteriophages induced from Enterohaemorrhagic Escherichia coli (EHEC, however Ф24B possesses significant regions of heterogeneity, with implications for phage biology and behaviour. The Ф24B genome was compared to other sequenced Stx phages and the archetypal lambdoid phage, lambda, using the Circos genome comparison tool and a PCR-based multi-loci comparison system. Conclusions The data support the hypothesis that Stx phages are mosaic, and recombination events between the host, phages and their remnants within the same infected bacterial cell will continue to drive the evolution of Stx phage variants and the subsequent dissemination of shigatoxigenic potential.

  18. Bacteriophages as surface and ground water tracers

    Science.gov (United States)

    Rossi, P.; Dörfliger, N.; Kennedy, K.; Müller, I.; Aragno, M.

    Bacteriophages are increasingly used as tracers for quantitative analysis in both hydrology and hydrogeology. The biological particles are neither toxic nor pathogenic for other living organisms as they penetrate only a specific bacterial host. They have many advantages over classical fluorescent tracers and offer the additional possibility of multi-point injection for tracer tests. Several years of research make them suitable for quantitative transport analysis and flow boundary delineation in both surface and ground waters, including karst, fractured and porous media aquifers. This article presents the effective application of bacteriophages based on their use in differing Swiss hydrological environments and compares their behaviour to conventional coloured dye or salt-type tracers. In surface water and karst aquifers, bacteriophages travel at about the same speed as the typically referenced fluorescent tracers (uranine, sulphurhodamine G extra). In aquifers of interstitial porosity, however, they appear to migrate more rapidly than fluorescent tracers, albeit with a significant reduction in their numbers within the porous media. This faster travel time implies that a modified rationale is needed for defining some ground water protection area boundaries. Further developments of other bacteriophages and their documentation as tracer methods should result in an accurate and efficient tracer tool that will be a proven alternative to conventional fluorescent dyes.

  19. An Undergraduate Laboratory Activity Demonstrating Bacteriophage Specificity

    Directory of Open Access Journals (Sweden)

    Mary E. Allen

    2013-02-01

    Full Text Available Bacteriophage are among the most diverse and numerous microbes inhabiting our planet. Yet many laboratory activities fail to engage students in meaningful exploration of their diversity, unique characteristics, and abundance. In this curriculum activity students use a standard plaque assay to enumerate bacteriophage particles from a natural sample and use the scientific method to address questions about host specificity and diversity. A raw primary sewage sample is enriched for bacteriophage using hosts in the family Enterobacteriaceae. Students hypothesize about host specificity and use quantitative data (serial dilution and plaque assay to test their hypotheses. Combined class data also help them answer questions about phage diversity. The exercise was field tested with a class of 47 students using pre- and posttests. For all learning outcomes posttest scores were higher than pretest scores at or below p = 0.01. Average individualized learning gain (G was also calculated for each learning outcome. Students’ use of scientific language in reference to bacteriophage and host interaction significantly improved (p = 0.002; G = 0.50. Improved means of expression helped students construct better hypotheses on phage host specificity (G = 0.31, p = 0.01 and to explain the plaque assay method (G = 0.33, p = 0.002. At the end of the exercise students also demonstrated improved knowledge and understanding of phage specificity as related to phage therapy in humans (p < 0.001; G = 51.

  20. STUDIES ON THE PURIFICATION OF BACTERIOPHAGE.

    Science.gov (United States)

    Kalmanson, G; Bronfenbrenner, J

    1939-11-20

    A simple method of concentrating and purifying bacteriophage has been described. The procedure consisted essentially in collecting the active agent on a reinforced collodion membrane of a porosity that would just retain all the active agent and permit extraneous material to pass through. Advantage was taken of the fact that B. coli will proliferate and regenerate bacteriophage in a completely diffusible synthetic medium with ammonia as the only source of nitrogen, which permitted the purification of the bacteriophage by copious washing. The material thus obtained was concentrated by suction and after thorough washing possessed all the activity of the original filtrate. It was labile, losing its activity in a few days on standing, and was quickly and completely inactivated upon drying. This material contained approximately 15 per cent of nitrogen and with 2 or 3 mg. samples of inactive dry residue it was possible to obtain positive protein color tests. The concentrated and purified bacteriophage has about 10(-14) mg. of nitrogen, or 6 x 10(-17) gm. of protein per unit of lytic activity. Assuming that each unit of activity represents a molecule, the calculated maximum average molecular weight would be approximately 36,000,000, and on the assumption of a spherical shape of particles and a density of 1.3, the calculated radius would be about 22 millimicra. By measurement of the diffusion rate, the average radius of particle of the fraction of the purified bacteriophage which diffuses most readily through a porous plate was found to be of the order of magnitude of 9 millimicra, or of a calculated molecular weight of 2,250,000. Furthermore, when this purified bacteriophage was fractionated by forcing it through a thin collodion membrane, which permits the passage of only the smaller particles, it was possible to demonstrate in the ultrafiltrate active particles of about 2 millimicra in radius, and of a calculated molecular weight of 25,000. It was of interest to apply

  1. Marine organisms as source of extracts to disrupt bacterial communication: bioguided isolation and identification of quorum sensing inhibitors from Ircinia felix

    Directory of Open Access Journals (Sweden)

    Jairo Quintana

    2015-06-01

    Full Text Available AbstractIn this study, 39 extracts from marine organisms were evaluated as quorum sensing inhibitors, collected in the Colombian Caribbean Sea and the Brazilian Coast including 26 sponges, seven soft corals, five algae and one zooanthid. The results showed that crude extracts from the soft coral Eunicea laciniata, and the sponges Svenzea tubulosa, Ircinia felix and Neopetrosia carbonaria were the most promising source of quorum sensing inhibitors compounds without affecting bacterial growth, unlike the raw extracts of Agelas citrina, Agelas tubulata, Iotrochota arenosa, Topsentia ophiraphidites, Niphates caycedoi, Cliona tenuis, Ptilocaulis walpersi, Petrosia pellasarca, and the algae Laurencia catarinensis and Laurencia obtusa, which displayed potent antibacterial activity against the biosensors employed. The crude extract from the sponge I. felix was fractionated, obtaining furanosesterterpenes which were identified and evaluated as quorum sensing inhibitors, showing a moderate activity without affecting the biosensor's growth.

  2. Die Begegnung der Hochstapler oder  : von der Vertracktheit der AggressionRobert Neumanns Olympia als Parodie auf Thomas Manns Bekenntnisse des Hochstaplers Felix Krull1

    OpenAIRE

    Pils, Holger

    2012-01-01

    Cet article met en lumière la richesse des allusions du roman Olympia (1961). Robert Neumann y aborde une problématique-clé de son œuvre : l’imposture. Ce roman, dédié à Thomas Mann et contre lequel ses héritiers ont intenté un procès pour plagiat, est une parodie de l’ouvrage. Felix Krull est un des personnages d’Olympia. Sa sœur, l’héroïne éponyme, est également empruntée au roman de Thomas Mann. Enfin, dans la rencontre de « Felix Krull » avec une autre figure d’imposteur, Neumann transcri...

  3. Evolution and the complexity of bacteriophages

    Directory of Open Access Journals (Sweden)

    Serwer Philip

    2007-03-01

    Full Text Available Abstract Background The genomes of both long-genome (> 200 Kb bacteriophages and long-genome eukaryotic viruses have cellular gene homologs whose selective advantage is not explained. These homologs add genomic and possibly biochemical complexity. Understanding their significance requires a definition of complexity that is more biochemically oriented than past empirically based definitions. Hypothesis Initially, I propose two biochemistry-oriented definitions of complexity: either decreased randomness or increased encoded information that does not serve immediate needs. Then, I make the assumption that these two definitions are equivalent. This assumption and recent data lead to the following four-part hypothesis that explains the presence of cellular gene homologs in long bacteriophage genomes and also provides a pathway for complexity increases in prokaryotic cells: (1 Prokaryotes underwent evolutionary increases in biochemical complexity after the eukaryote/prokaryote splits. (2 Some of the complexity increases occurred via multi-step, weak selection that was both protected from strong selection and accelerated by embedding evolving cellular genes in the genomes of bacteriophages and, presumably, also archaeal viruses (first tier selection. (3 The mechanisms for retaining cellular genes in viral genomes evolved under additional, longer-term selection that was stronger (second tier selection. (4 The second tier selection was based on increased access by prokaryotic cells to improved biochemical systems. This access was achieved when DNA transfer moved to prokaryotic cells both the more evolved genes and their more competitive and complex biochemical systems. Testing the hypothesis I propose testing this hypothesis by controlled evolution in microbial communities to (1 determine the effects of deleting individual cellular gene homologs on the growth and evolution of long genome bacteriophages and hosts, (2 find the environmental conditions that

  4. Bacteriophages and bacteriophage-derived endolysins as potential therapeutics to combat Gram-positive spore forming bacteria.

    Science.gov (United States)

    Nakonieczna, A; Cooper, C J; Gryko, R

    2015-09-01

    Since their discovery in 1915, bacteriophages have been routinely used within Eastern Europe to treat a variety of bacterial infections. Although initially ignored by the West due to the success of antibiotics, increasing levels and diversity of antibiotic resistance is driving a renaissance for bacteriophage-derived therapy, which is in part due to the highly specific nature of bacteriophages as well as their relative abundance. This review focuses on the bacteriophages and derived lysins of relevant Gram-positive spore formers within the Bacillus cereus group and Clostridium genus that could have applications within the medical, food and environmental sectors.

  5. Application of bacteriophages in sensor development.

    Science.gov (United States)

    Peltomaa, Riikka; López-Perolio, Irene; Benito-Peña, Elena; Barderas, Rodrigo; Moreno-Bondi, María Cruz

    2016-03-01

    Bacteriophage-based bioassays are a promising alternative to traditional antibody-based immunoassays. Bacteriophages, shortened to phages, can be easily conjugated or genetically engineered. Phages are robust, ubiquitous in nature, and harmless to humans. Notably, phages do not usually require inoculation and killing of animals; and thus, the production of phages is simple and economical. In recent years, phage-based biosensors have been developed featuring excellent robustness, sensitivity, and selectivity in combination with the ease of integration into transduction devices. This review provides a critical overview of phage-based bioassays and biosensors developed in the last few years using different interrogation methods such as colorimetric, enzymatic, fluorescence, surface plasmon resonance, quartz crystal microbalance, magnetoelastic, Raman, or electrochemical techniques.

  6. Detection of bacteria with bioluminescent reporter bacteriophage.

    Science.gov (United States)

    Klumpp, Jochen; Loessner, Martin J

    2014-01-01

    Bacteriophages are viruses that exclusively infect bacteria. They are ideally suited for the development of highly specific diagnostic assay systems. Bioluminescent reporter bacteriophages are designed and constructed by integration of a luciferase gene in the virus genome. Relying on the host specificity of the phage, the system enables rapid, sensitive, and specific detection of bacterial pathogens. A bioluminescent reporter phage assay is superior to any other molecular detection method, because gene expression and light emission are dependent on an active metabolism of the bacterial cell, and only viable cells will yield a signal. In this chapter we introduce the concept of creating reporter phages, discuss their advantages and disadvantages, and illustrate the advances made in developing such systems for different Gram-negative and Gram-positive pathogens. The application of bioluminescent reporter phages for the detection of foodborne pathogens is emphasized.

  7. Bacteriophages as recognition and identification agents

    Energy Technology Data Exchange (ETDEWEB)

    Teodorescu, M.C.; Gaspar, A.

    1987-04-23

    Bacteriophages are employed as agents for recognition and identification of molecules and cellular materials, using their ability to recognize their bacterial host, by coating them with antibodies or by selecting them to perform in a manner analogous to antibodies. Visibility for identification is effected by incorporating a fluorescent agent, a radioisotope, a metal, an enzyme, or other staining material. The method of this invention may be utilized in selected clinical procedures, and is adaptable to use in an assay kit.

  8. Going viral: designing bioactive surfaces with bacteriophage.

    Science.gov (United States)

    Hosseinidoust, Zeinab; Olsson, Adam L J; Tufenkji, Nathalie

    2014-12-01

    Bacteriophage-functionalized bioactive surfaces are functional materials that can be used as antimicrobial surfaces in medical applications (e.g., indwelling medical devices or wound dressings) or as biosensors for bacterial capture and detection. Despite offering immense potential, designing efficient phage-functionalized bioactive surfaces is hampered by a number of challenges. This review offers an overview of the current state of knowledge in this field and presents a critical perspective of the technological promises and challenges.

  9. A new look at bacteriophage phylogenomics

    OpenAIRE

    Nóbrega, Franklin; Pinto, Graça; Azeredo, Joana; Kluskens, Leon

    2012-01-01

    Bacteriophages or phages are viruses that only infect bacteria. The International Committee on Taxonomy of Viruses classified these viruses in accordance with the morphology of their free virion particles and type and size of their genome. This system fails on the classification of several phages, which have their genome already sequenced. It also requires a morphological analysis by transmission electron microscopy, which is very expensive and time consuming [1]. In 2002 Rohwe...

  10. Genomic impact of CRISPR immunization against bacteriophages.

    Science.gov (United States)

    Barrangou, Rodolphe; Coûté-Monvoisin, Anne-Claire; Stahl, Buffy; Chavichvily, Isabelle; Damange, Florian; Romero, Dennis A; Boyaval, Patrick; Fremaux, Christophe; Horvath, Philippe

    2013-12-01

    CRISPR (clustered regularly interspaced short palindromic repeats) together with CAS (RISPR-associated) genes form the CRISPR-Cas immune system, which provides sequence-specific adaptive immunity against foreign genetic elements in bacteria and archaea. Immunity is acquired by the integration of short stretches of invasive DNA as novel 'spacers' into CRISPR loci. Subsequently, these immune markers are transcribed and generate small non-coding interfering RNAs that specifically guide nucleases for sequence-specific cleavage of complementary sequences. Among the four CRISPR-Cas systems present in Streptococcus thermophilus, CRISPR1 and CRISPR3 have the ability to readily acquire new spacers following bacteriophage or plasmid exposure. In order to investigate the impact of building CRISPR-encoded immunity on the host chromosome, we determined the genome sequence of a BIM (bacteriophage-insensitive mutant) derived from the DGCC7710 model organism, after four consecutive rounds of bacteriophage challenge. As expected, active CRISPR loci evolved via polarized addition of several novel spacers following exposure to bacteriophages. Although analysis of the draft genome sequence revealed a variety of SNPs (single nucleotide polymorphisms) and INDELs (insertions/deletions), most of the in silico differences were not validated by Sanger re-sequencing. In addition, two SNPs and two small INDELs were identified and tracked in the intermediate variants. Overall, building CRISPR-encoded immunity does not significantly affect the genome, which allows the maintenance of important functional properties in isogenic CRISPR mutants. This is critical for the development and formulation of sustainable and robust next-generation starter cultures with increased industrial lifespans.

  11. Isolation of Arthrobacter Bacteriophage from Soil †

    OpenAIRE

    Germida, James J.; Casida, L. E.

    1981-01-01

    Soil was percolated with water and various nutrient solutions, and then the percolates were analyzed for bacteriophages which produced plaques on various Arthrobacter strains. The water percolates did not contain detectable phage. In contrast, phages for A. globiformis strains ATCC 8010 and 4336, and for several recent Arthrobacter species soil isolates, were easily detected in nutrient broth, soil extract, and cation-complete medium percolates. These percolates did not contain phage that pro...

  12. Use of bacteriophages to control biofilms

    OpenAIRE

    Sillankorva, Sanna

    2009-01-01

    Tese de doutoramento em Engenharia Química e Biológica After several years of abandonment, the use of bacteriophages (phages) for killing bacteria has withdrawn recent attention and reappraisal. This has led to a vast phage research, in varied fields, with impressive outcomes and currently several studies are ongoing with animals, horticulture and agriculture products, and even with humans. Despite this enthusiasm, there is a lack of research conserning phage utilization to red...

  13. Genetically modified bacteriophages in applied microbiology.

    Science.gov (United States)

    Bárdy, P; Pantůček, R; Benešík, M; Doškař, J

    2016-09-01

    Bacteriophages represent a simple viral model of basic research with many possibilities for practical application. Due to their ability to infect and kill bacteria, their potential in the treatment of bacterial infection has been examined since their discovery. With advances in molecular biology and gene engineering, the phage application spectrum has been expanded to various medical and biotechnological fields. The construction of bacteriophages with an extended host range or longer viability in the mammalian bloodstream enhances their potential as an alternative to conventional antibiotic treatment. Insertion of active depolymerase genes to their genomes can enforce the biofilm disposal. They can also be engineered to transfer various compounds to the eukaryotic organisms and the bacterial culture, applicable for the vaccine, drug or gene delivery. Phage recombinant lytic enzymes can be applied as enzybiotics in medicine as well as in biotechnology for pathogen detection or programmed cell death in bacterial expression strains. Besides, modified bacteriophages with high specificity can be applied as bioprobes in detection tools to estimate the presence of pathogens in food industry, or utilized in the control of food-borne pathogens as part of the constructed phage-based biosorbents.

  14. Genetically modified bacteriophages in applied microbiology.

    Science.gov (United States)

    Bárdy, P; Pantůček, R; Benešík, M; Doškař, J

    2016-09-01

    Bacteriophages represent a simple viral model of basic research with many possibilities for practical application. Due to their ability to infect and kill bacteria, their potential in the treatment of bacterial infection has been examined since their discovery. With advances in molecular biology and gene engineering, the phage application spectrum has been expanded to various medical and biotechnological fields. The construction of bacteriophages with an extended host range or longer viability in the mammalian bloodstream enhances their potential as an alternative to conventional antibiotic treatment. Insertion of active depolymerase genes to their genomes can enforce the biofilm disposal. They can also be engineered to transfer various compounds to the eukaryotic organisms and the bacterial culture, applicable for the vaccine, drug or gene delivery. Phage recombinant lytic enzymes can be applied as enzybiotics in medicine as well as in biotechnology for pathogen detection or programmed cell death in bacterial expression strains. Besides, modified bacteriophages with high specificity can be applied as bioprobes in detection tools to estimate the presence of pathogens in food industry, or utilized in the control of food-borne pathogens as part of the constructed phage-based biosorbents. PMID:27321680

  15. Call for a dedicated European legal framework for bacteriophage therapy.

    Science.gov (United States)

    Verbeken, Gilbert; Pirnay, Jean-Paul; Lavigne, Rob; Jennes, Serge; De Vos, Daniel; Casteels, Minne; Huys, Isabelle

    2014-04-01

    The worldwide emergence of antibiotic resistances and the drying up of the antibiotic pipeline have spurred a search for alternative or complementary antibacterial therapies. Bacteriophages are bacterial viruses that have been used for almost a century to combat bacterial infections, particularly in Poland and the former Soviet Union. The antibiotic crisis has triggered a renewed clinical and agricultural interest in bacteriophages. This, combined with new scientific insights, has pushed bacteriophages to the forefront of the search for new approaches to fighting bacterial infections. But before bacteriophage therapy can be introduced into clinical practice in the European Union, several challenges must be overcome. One of these is the conceptualization and classification of bacteriophage therapy itself and the extent to which it constitutes a human medicinal product regulated under the European Human Code for Medicines (Directive 2001/83/EC). Can therapeutic products containing natural bacteriophages be categorized under the current European regulatory framework, or should this framework be adapted? Various actors in the field have discussed the need for an adapted (or entirely new) regulatory framework for the reintroduction of bacteriophage therapy in Europe. This led to the identification of several characteristics specific to natural bacteriophages that should be taken into consideration by regulators when evaluating bacteriophage therapy. One important consideration is whether bacteriophage therapy development occurs on an industrial scale or a hospital-based, patient-specific scale. More suitable regulatory standards may create opportunities to improve insights into this promising therapeutic approach. In light of this, we argue for the creation of a new, dedicated European regulatory framework for bacteriophage therapy. PMID:24500660

  16. Isolation and characterization of bacteriophages of Salmonella enterica serovar Pullorum.

    Science.gov (United States)

    Bao, H; Zhang, H; Wang, R

    2011-10-01

    In this study, 2 bacteriophages of Salmonella Pullorum were isolated using an enrichment protocol and the double agar layer method. They were named PSPu-95 and PSPu-4-116, respectively, against clinical isolates of Salmonella Pullorum SPu-95 and SPu-116. The host ranges of the 2 bacteriophages were determined by performing spot tests with 20 bacteria strains. Both bacteriophages had wide host ranges. Bacteriophage PSPu-95 had a lytic effect on 17 of the 20 isolates (85%), and PSPu-4-116 produced a lytic effect on 14 isolates (70%) and was the only bacteriophage that produced a clear plaque on enterotoxigenic Escherichia coli K88. Transmission electron microscopy revealed the bacteriophages belonged to the order Caudovirales. Bacteriophage PSPu-95 was a member of the family Siphoviridae, but bacteriophage PSPu-4-116 belonged to the family Myoviridae. Both had a double-stranded DNA, which was digested with HindIII or EcoRI, that was estimated to be 58.3 kbp (PSPu-95) and 45.2 kbp (PSPu-4-116) by 1% agar electrophoresis. One-step growth kinetics showed that the latent periods were all less than 20 min, and the burst size was 77.5 pfu/cell for PSPu-95 and 86 pfu/cell for PSPu-4-116. The bacteriophages were able to survive in a pH range between 4 and 10, and they were able to survive in a treatment of 70°C for 60 min. The characterizations of these 2 bacteriophages were helpful in establishing a basis for adopting the most effective bacteriophage to control bacteria in the poultry industry.

  17. Bacteriophage P70: unique morphology and unrelatedness to other Listeria bacteriophages.

    Science.gov (United States)

    Schmuki, Martina M; Erne, Doris; Loessner, Martin J; Klumpp, Jochen

    2012-12-01

    Listeria monocytogenes is an important food-borne pathogen, and its bacteriophages find many uses in detection and biocontrol of its host. The novel broad-host-range virulent phage P70 has a unique morphology with an elongated capsid. Its genome sequence was determined by a hybrid sequencing strategy employing Sanger and PacBio techniques. The P70 genome contains 67,170 bp and 119 open reading frames (ORFs). Our analyses suggest that P70 represents an archetype of virus unrelated to other known Listeria bacteriophages.

  18. Use of Asteraceae species by rural communities in Northeastern Brazil: reports in Camocim de Sao Felix, Pernambuco, Brazil

    Directory of Open Access Journals (Sweden)

    Laise de Holanda Cavalcanti Andrade

    2013-06-01

    Full Text Available Asteraceae, with around 2,000 species registered in Brazil, stand out in the ethnobotanical studies, placing them almost always among the four families with the greatest number of species in the useful flora, especially for medicinal purposes. In this study, one investigated the importance of this family in four rural communities in the town of Camocim de Sao Felix, in an altitude swamp, in the agreste region of the State of Pernambuco, Brazil. The field works were conducted within the period from December 2010 to May 2011. For the collection of ethnobotanical data, semi-structured interviews were conducted with 50 inhabitants, of both sexes, most of them farmers, with family income less than one minimum wage, and there was collection of species cited by them. The respondents showed a varied knowledge on the Asteraceae, citing 19 species, in the following categories: medicinal (12, ornamental (6, technological (3, and alimentary (2, some of them included in more than one category. Acanthospermum hispidum DC., ruderal species know as bristly starbur, was the most frequently cited as medicinal plant, indicated for the treatment of respiratory problems, infections, kidney diseases, and toothaches. The species Dahlia pinnata Cav., Tagetes erecta L., and Zinnia elegans Jacq. are used as ornamental plants. Lactuce sativa L. (cultivated and Emilia sonchifolia (L. DC. (weed were the only ones cited as alimentary and Conyza bonariensis (L. Cronquist, Egletes viscosa Less., and Parthenium hysterophorus L. were cited for technological purposes.

  19. Experience of the Eliava Institute in bacteriophage therapy

    Institute of Scientific and Technical Information of China (English)

    Mzia; Kutateladze

    2015-01-01

    <正>The rapid propagation of multidrug resistant bacterial strains is leading to renewed interest in bacteriophage therapy.With challenges in the treatment of bacterial infections,it is essential for people worldwide to understand how alternative approaches,such as bacteriophages,could be used to combat antibiotic resistant bacteria.The Eliava Institute

  20. Sequence and comparative analysis of Leuconostoc dairy bacteriophages

    DEFF Research Database (Denmark)

    Kot, Witold; Hansen, Lars Henrik; Neve, Horst;

    2014-01-01

    Bacteriophages attacking Leuconostoc species may significantly influence the quality of the final product. There is however limited knowledge of this group of phages in the literature. We have determined the complete genome sequences of nine Leuconostoc bacteriophages virulent to either Leuconostoc...

  1. Bacteriophages: The viruses for all seasons of molecular biology

    Directory of Open Access Journals (Sweden)

    Karam Jim D

    2005-03-01

    Full Text Available Abstract Bacteriophage research continues to break new ground in our understanding of the basic molecular mechanisms of gene action and biological structure. The abundance of bacteriophages in nature and the diversity of their genomes are two reasons why phage research brims with excitement. The pages of Virology Journal will reflect the excitement of the "New Phage Biology."

  2. POSSIBILITES OF BACTERIOPHAGES APPLICATION IN SURGERY AND TRANSPLANTATION

    Directory of Open Access Journals (Sweden)

    N.I. Gabrielyan

    2012-01-01

    Full Text Available The review of the modern data about bacteriophages and to their application to surgery is presented. Interest to bacteriophages is closely connected with an urgency of a problem of postoperative infectious complications and to resistance increase nosocomial species microbes to antibiotics. Successful demonstrative application of bacteriophages on experimental models for a reduction of is conditional-pathogenic microbes in biofilms, for treatment septicemia at the animals, caused resistance species P. aeruginosa, Klebsiella spp., Staphylococcus and other microbes is described. Positive results on application of bacteriophages in surgery are received at treatment of the infected wounds, peritonitis, infectious complications after liver and kidney transplantation. New mechanisms of action of bacteriophages, including their influence on transplantology immunity are resulted. Use of phages as alternatives of treatment and preventive maintenance of a superinfection at imunocomprometive patients is perspective. 

  3. The effects of bacteriophage and nanoparticles on microbial processes

    Science.gov (United States)

    Moody, Austin L.

    There are approximately 1031 tailed phages in the biosphere, making them the most abundant organism. Bacteriophages are viruses that infect bacteria. Due to the large diversity and abundance, no two bacteriophages that have been isolated are genetically the same. Phage products have potential in disease therapy to solve bacteria-related problems, such as infections resulting from resistant strains of Staphylococcus aureus. A bacteriophage capable of infecting methicillin-resistant S. aureus (MRSA) was isolated from bovine hair. The bacteriophage, named JB phage, was characterized using purification, amplification, cesium chloride banding, scanning electron microscopy, and transmission electron microscopy. JB phage and nanoparticles were used in various in vitro and in vivo models to test their effects on microbial processes. Scanning and transmission electron microscopy studies revealed strong interactions between JB phage and nanoparticles, which resulted in increased bacteriophage infectivity. JB phage and nanoparticle cocktails were used as a therapeutic to treat skin and systemic infections in mice caused by MRSA.

  4. [THE IDENTIFICATION AND DIFFERENTIATION OF BACTERIOPHAGES OF HUMAN PATHOGENIC VIBRIO].

    Science.gov (United States)

    Gaevskaia, N E; Kudriakova, T A; Makedonova, L D; Kachkina, G V

    2015-04-01

    The issue of identification and differentiation of large group of bacteriophages of human pathogenic vibrio is still unresolved. In research and practical applied purposes it is important to consider characteristics of bacteriophages for establishing similarity and differences between them. The actual study was carried out to analyze specimens of DNA-containing bacteriophages of pathogenic vibrio. The overwhelming majority of them characterized by complicated type of symmetry--phages with double-helical DNA and also phages with mono-helical DNA structure discovered recently in vibrio. For the first time, the general framework of identification and differentiation of bacteriophages of pathogenic vibrio was developed. This achievement increases possibility to establish species assignment of phages and to compare with phages registered in the database. "The collection of bacteriophages and test-strains of human pathogenic vibrio" (No2010620549 of 24.09.210).

  5. M13 Bacteriophage Based Protein Sensors

    Science.gov (United States)

    Lee, Ju Hun

    Despite significant progress in biotechnology and biosensing, early detection and disease diagnosis remains a critical issue for improving patient survival rates and well-being. Many of the typical detection schemes currently used possess issues such as low sensitivity and accuracy and are also time consuming to run and expensive. In addition, multiplexed detection remains difficult to achieve. Therefore, developing advanced approaches for reliable, simple, quantitative analysis of multiple markers in solution that also are highly sensitive are still in demand. In recent years, much of the research has primarily focused on improving two key components of biosensors: the bio-recognition agent (bio-receptor) and the transducer. Particular bio-receptors that have been used include antibodies, aptamers, molecular imprinted polymers, and small affinity peptides. In terms of transducing agents, nanomaterials have been considered as attractive candidates due to their inherent nanoscale size, durability and unique chemical and physical properties. The key focus of this thesis is the design of a protein detection and identification system that is based on chemically engineered M13 bacteriophage coupled with nanomaterials. The first chapter provides an introduction of biosensors and M13 bacteriophage in general, where the advantages of each are provided. In chapter 2, an efficient and enzyme-free sensor is demonstrated from modified M13 bacteriophage to generate highly sensitive colorimetric signals from gold nanocrystals. In chapter 3, DNA conjugated M13 were used to enable facile and rapid detection of antigens in solution that also provides modalities for identification. Lastly, high DNA loadings per phage was achieved via hydrozone chemistry and these were applied in conjunction with Raman active DNA-gold/silver core/shell nanoparticles toward highly sensitive SERS sensing.

  6. Genesis of Pre-Hurricane Felix (2007). Part 1; The Role of the Easterly Wave Critical Layer

    Science.gov (United States)

    Wang, Zhuo; Montgomery, M. T.; Dunkerton, T. J.

    2010-01-01

    The formation of pre Hurricane Felix (2007) in a tropical easterly wave is examined in a two-part study using the Weather Research and Forecasting (WRF) model with a high-resolution nested grid configuration that permits the representation of cloud system processes. The simulation commences during the wave stage of the precursor African easterly-wave disturbance. Here the simulated and observed developments are compared, while in Part II of the study various large-scale analyses, physical parameterizations, and initialization times are explored to document model sensitivities. In this first part the authors focus on the wave/vortex morphology, its interaction with the adjacent intertropical convergence zone complex, and the vorticity balance in the neighborhood of the developing storm. Analysis of the model simulation points to a bottom-up development process within the wave critical layer and supports the three new hypotheses of tropical cyclone formation proposed recently by Dunkerton, Montgomery, and Wang. It is shown also that low-level convergence associated with the ITCZ helps to enhance the wave signal and extend the "wave pouch" from the jet level to the top of the atmospheric boundary layer. The region of a quasi-closed Lagrangian circulation within the wave pouch provides a focal point for diabatic merger of convective vortices and their vortical remnants. The wave pouch serves also to protect the moist air inside from dry air intrusion, providing a favorable environment for sustained deep convection. Consistent with the authors' earlier findings, the tropical storm forms near the center of the wave pouch via system-scale convergence in the lower troposphere and vorticity aggregation. Components of the vorticity balance are shown to be scale dependent, with the immediate effects of cloud processes confined more closely to the storm center than the overturning Eliassen circulation induced by diabatic heating, the influence of which extends to larger radii.

  7. Ecological study of bacteriophages of Vibrio natriegens

    Energy Technology Data Exchange (ETDEWEB)

    Zachary, A.

    1978-03-01

    Effects of temperature and anaerobic conditions on the replication of two bacteriophages, nt-1 and nt-6, of the estuarine bacterium Vibrio natriegens were studied. Reduction in temperature resulted in longer latent periods and reduced burst sizes for both phages. Replication under anaerobic conditions resulted in longer latent periods; however, phage nt-6 had a reduced burst size, whereas phage nt-1 had an increased burst size, resulting in a rate of phage production nearly equal to that observed under aerobic conditions. Therefore the distribution of the phages in marsh areas could be influenced by temperature and anaerobiosis.

  8. Bacteriophage biosensors for antibiotic-resistant bacteria.

    Science.gov (United States)

    Sorokulova, Irina; Olsen, Eric; Vodyanoy, Vitaly

    2014-03-01

    An increasing number of disease-causing bacteria are resistant to one or more anti-bacterial drugs utilized for therapy. Early and speedy detection of these pathogens is therefore very important. Traditional pathogen detection techniques, that include microbiological and biochemical assays are long and labor-intensive, while antibody or DNA-based methods require substantial sample preparation and purification. Biosensors based on bacteriophages have demonstrated remarkable potential to surmount these restrictions and to offer rapid, efficient and sensitive detection technique for antibiotic-resistant bacteria.

  9. Bacteriophages and Their Role in Food Safety

    Directory of Open Access Journals (Sweden)

    Sanna M. Sillankorva

    2012-01-01

    Full Text Available The interest for natural antimicrobial compounds has increased due to alterations in consumer positions towards the use of chemical preservatives in foodstuff and food processing surfaces. Bacteriophages fit in the class of natural antimicrobial and their effectiveness in controlling bacterial pathogens in agro-food industry has led to the development of different phage products already approved by USFDA and USDA. The majority of these products are to be used in farm animals or animal products such as carcasses, meats and also in agricultural and horticultural products. Treatment with specific phages in the food industry can prevent the decay of products and the spread of bacterial diseases and ultimately promote safe environments in animal and plant food production, processing, and handling. This is an overview of recent work carried out with phages as tools to promote food safety, starting with a general introduction describing the prevalence of foodborne pathogens and bacteriophages and a more detailed discussion on the use of phage therapy to prevent and treat experimentally induced infections of animals against the most common foodborne pathogens, the use of phages as biocontrol agents in foods, and also their use as biosanitizers of food contact surfaces.

  10. Bacteriophage recombination systems and biotechnical applications.

    Science.gov (United States)

    Nafissi, Nafiseh; Slavcev, Roderick

    2014-04-01

    Bacteriophage recombination systems have been widely used in biotechnology for modifying prokaryotic species, for creating transgenic animals and plants, and more recently, for human cell gene manipulation. In contrast to homologous recombination, which benefits from the endogenous recombination machinery of the cell, site-specific recombination requires an exogenous source of recombinase in mammalian cells. The mechanism of bacteriophage evolution and their coexistence with bacterial cells has become a point of interest ever since bacterial viruses' life cycles were first explored. Phage recombinases have already been exploited as valuable genetic tools and new phage enzymes, and their potential application to genetic engineering and genome manipulation, vectorology, and generation of new transgene delivery vectors, and cell therapy are attractive areas of research that continue to be investigated. The significance and role of phage recombination systems in biotechnology is reviewed in this paper, with specific focus on homologous and site-specific recombination conferred by the coli phages, λ, and N15, the integrase from the Streptomyces phage, ΦC31, the recombination system of phage P1, and the recently characterized recombination functions of Yersinia phage, PY54. Key steps of the molecular mechanisms involving phage recombination functions and their application to molecular engineering, our novel exploitations of the PY54-derived recombination system, and its application to the development of new DNA vectors are discussed.

  11. Understanding Bacteriophage Specificity in Natural Microbial Communities

    Directory of Open Access Journals (Sweden)

    Britt Koskella

    2013-03-01

    Full Text Available Studying the coevolutionary dynamics between bacteria and the bacteriophage viruses that infect them is critical to understanding both microbial diversity and ecosystem functioning. Phages can play a key role in shaping bacterial population dynamics and can significantly alter both intra- and inter-specific competition among bacterial hosts. Predicting how phages might influence community stability and apparent competition, however, requires an understanding of how bacteria-phage interaction networks evolve as a function of host diversity and community dynamics. Here, we first review the progress that has been made in understanding phage specificity, including the use of experimental evolution, we then introduce a new dataset on natural bacteriophages collected from the phyllosphere of horse chestnut trees, and finally we highlight that bacterial sensitivity to phage is rarely a binary trait and that this variation should be taken into account and reported. We emphasize that there is currently insufficient evidence to make broad generalizations about phage host range in natural populations, the limits of phage adaptation to novel hosts, or the implications of phage specificity in shaping microbial communities. However, the combination of experimental and genomic approaches with the study of natural communities will allow new insight to the evolution and impact of phage specificity within complex bacterial communities.

  12. Bacteriophage recombination systems and biotechnical applications.

    Science.gov (United States)

    Nafissi, Nafiseh; Slavcev, Roderick

    2014-04-01

    Bacteriophage recombination systems have been widely used in biotechnology for modifying prokaryotic species, for creating transgenic animals and plants, and more recently, for human cell gene manipulation. In contrast to homologous recombination, which benefits from the endogenous recombination machinery of the cell, site-specific recombination requires an exogenous source of recombinase in mammalian cells. The mechanism of bacteriophage evolution and their coexistence with bacterial cells has become a point of interest ever since bacterial viruses' life cycles were first explored. Phage recombinases have already been exploited as valuable genetic tools and new phage enzymes, and their potential application to genetic engineering and genome manipulation, vectorology, and generation of new transgene delivery vectors, and cell therapy are attractive areas of research that continue to be investigated. The significance and role of phage recombination systems in biotechnology is reviewed in this paper, with specific focus on homologous and site-specific recombination conferred by the coli phages, λ, and N15, the integrase from the Streptomyces phage, ΦC31, the recombination system of phage P1, and the recently characterized recombination functions of Yersinia phage, PY54. Key steps of the molecular mechanisms involving phage recombination functions and their application to molecular engineering, our novel exploitations of the PY54-derived recombination system, and its application to the development of new DNA vectors are discussed. PMID:24442504

  13. Vibrio cholerae O1 isolated in Kenya.

    OpenAIRE

    Iwanaga, M; Mori, K.; Kaviti, J N

    1982-01-01

    Biological and serological analyses of 272 isolates of Vibrio cholerae O1 from six epidemics and from a few sporadic cases in Kenya were carried out. All of the isolates were identified as V. cholerae biotype E1 Tor, and 210 out of 272 isolates were hemolytic as examined by Feeley's method.

  14. Combined use of Bacteriophage K and a novel Bacteriophage to reduce Staphylococcus aureus biofilm formation

    DEFF Research Database (Denmark)

    Alves, D.R.; Gaudion, A.; Bean, J.E.;

    2014-01-01

    Biofilms are major causes of impairment of wound healing and patient morbidity. One of the most common and aggressive wound pathogens is Staphylococcus aureus, displaying a large repertoire of virulence factors and commonly reduced susceptibility to antibiotics, such as the spread of methicillin-......-resistant S. aureus (MRSA). Bacteriophages are obligate parasites of bacteria. They multiply intracellularly and lyse their bacterial host, releasing their progeny. We isolated a novel phage, DRA88, which has a ...

  15. Bacteria vs. Bacteriophages: Parallel Evolution of Immune Arsenals.

    Science.gov (United States)

    Shabbir, Muhammad A B; Hao, Haihong; Shabbir, Muhammad Z; Wu, Qin; Sattar, Adeel; Yuan, Zonghui

    2016-01-01

    Bacteriophages are the most common entities on earth and represent a constant challenge to bacterial populations. To fend off bacteriophage infection, bacteria evolved immune systems to avert phage adsorption and block invader DNA entry. They developed restriction-modification systems and mechanisms to abort infection and interfere with virion assembly, as well as newly recognized clustered regularly interspaced short palindromic repeats (CRISPR). In response to bacterial immune systems, bacteriophages synchronously evolved resistance mechanisms, such as the anti-CRISPR systems to counterattack bacterial CRISPR-cas systems, in a continuing evolutionary arms race between virus and host. In turn, it is fundamental to the survival of the bacterial cell to evolve a system to combat bacteriophage immune strategies.

  16. Bacteria vs. bacteriophages: parallel evolution of immune arsenals

    Directory of Open Access Journals (Sweden)

    Muhammad Abu Bakr Shabbir

    2016-08-01

    Full Text Available Bacteriophages are the most common entities on earth and represent a constant challenge to bacterial populations. To fend off bacteriophage infection, bacteria evolved immune systems to avert phage adsorption and block invader DNA entry. They developed restriction-modification systems and mechanisms to abort infection and interfere with virion assembly, as well as newly recognized clustered regularly interspaced short palindromic repeats (CRISPR. In response to bacterial immune systems, bacteriophages synchronously evolved resistance mechanisms, such as the anti-CRISPR systems to counterattack bacterial CRISPR-cas systems, in a continuing evolutionary arms race between virus and host. In turn, it is fundamental to the survival of the bacterial cell to evolve a system to combat bacteriophage immune strategies.

  17. Antimicrobial bacteriophage-derived proteins and therapeutic applications

    Science.gov (United States)

    Antibiotics have the remarkable power to control bacterial infections. Unfortunately, widespread use, whether regarded as prudent or not, has favored the emergence and persistence of antibiotic resistant strains of human pathogenic bacteria, resulting in a global health threat. Bacteriophages (pha...

  18. Bacteriophage-based nanoprobes for rapid bacteria separation

    Science.gov (United States)

    Chen, Juhong; Duncan, Bradley; Wang, Ziyuan; Wang, Li-Sheng; Rotello, Vincent M.; Nugen, Sam R.

    2015-10-01

    The lack of practical methods for bacterial separation remains a hindrance for the low-cost and successful development of rapid detection methods from complex samples. Antibody-tagged magnetic particles are commonly used to pull analytes from a liquid sample. While this method is well-established, improvements in capture efficiencies would result in an increase of the overall detection assay performance. Bacteriophages represent a low-cost and more consistent biorecognition element as compared to antibodies. We have developed nanoscale bacteriophage-tagged magnetic probes, where T7 bacteriophages were bound to magnetic nanoparticles. The nanoprobe allowed the specific recognition and attachment to E. coli cells. The phage magnetic nanprobes were directly compared to antibody-conjugated magnetic nanoprobes. The capture efficiencies of bacteriophages and antibodies on nanoparticles for the separation of E. coli K12 at varying concentrations were determined. The results indicated a similar bacteria capture efficiency between the two nanoprobes.The lack of practical methods for bacterial separation remains a hindrance for the low-cost and successful development of rapid detection methods from complex samples. Antibody-tagged magnetic particles are commonly used to pull analytes from a liquid sample. While this method is well-established, improvements in capture efficiencies would result in an increase of the overall detection assay performance. Bacteriophages represent a low-cost and more consistent biorecognition element as compared to antibodies. We have developed nanoscale bacteriophage-tagged magnetic probes, where T7 bacteriophages were bound to magnetic nanoparticles. The nanoprobe allowed the specific recognition and attachment to E. coli cells. The phage magnetic nanprobes were directly compared to antibody-conjugated magnetic nanoprobes. The capture efficiencies of bacteriophages and antibodies on nanoparticles for the separation of E. coli K12 at varying

  19. Targeting Antibacterial Agents by Using Drug-Carrying Filamentous Bacteriophages

    OpenAIRE

    Yacoby, Iftach; Shamis, Marina; Bar, Hagit; Shabat, Doron; Benhar, Itai

    2006-01-01

    Bacteriophages have been used for more than a century for (unconventional) therapy of bacterial infections, for half a century as tools in genetic research, for 2 decades as tools for discovery of specific target-binding proteins, and for nearly a decade as tools for vaccination or as gene delivery vehicles. Here we present a novel application of filamentous bacteriophages (phages) as targeted drug carriers for the eradication of (pathogenic) bacteria. The phages are genetically modified to d...

  20. Alternative bacteriophage life cycles: the carrier state of Campylobacter jejuni

    OpenAIRE

    Siringan, Patcharin; Connerton, Phillippa L.; Cummmings, Nicola J.; Connerton, Ian F.

    2014-01-01

    Members of the genus Campylobacter are frequently responsible for human enteric disease, often through consumption of contaminated poultry products. Bacteriophages are viruses that have the potential to control pathogenic bacteria, but understanding their complex life cycles is key to their successful exploitation. Treatment of Campylobacter jejuni biofilms with bacteriophages led to the discovery that phages had established a relationship with their hosts typical of the carrier state life cy...

  1. Engineered bacteriophage targeting gene networks as adjuvants for antibiotic therapy

    OpenAIRE

    Lu, Timothy K.; Collins, James J.

    2009-01-01

    Antimicrobial drug development is increasingly lagging behind the evolution of antibiotic resistance, and as a result, there is a pressing need for new antibacterial therapies that can be readily designed and implemented. In this work, we engineered bacteriophage to overexpress proteins and attack gene networks that are not directly targeted by antibiotics. We show that suppressing the SOS network in Escherichia coli with engineered bacteriophage enhances killing by quinolones by several orde...

  2. FoxO1 in embryonic development

    OpenAIRE

    Ferdous, Anwarul; Hill, Joseph A.

    2012-01-01

    Establishment of the maternal-fetal circulation during embryonic development is a fundamental process required for effective exchange of nutrients, waste products and signaling factors critical to all subsequent stages of fetal growth and development. Recent work has uncovered a previously unrecognized role of the transcription factor FoxO1 in the orchestration of molecular events underlying establishment of maternal-fetal circulatory interaction. These new data contribute to a larger body of...

  3. Biological characterization of v. Cholerae-specific bacteriophages isolated from water sources in Georgia.

    Science.gov (United States)

    Elbakidze, T; Kokashvili, T; Janelidze, N; Porchkhidze, K; Koberidze, T; Tediashvili, M

    2015-03-01

    Vibrio cholerae, a widely spread bacterium in various marine, fresh, and brackish water environments, can cause a devastating diarrheal disease - cholera and also mild forms of gastroenteritis. Bacterial viruses are natural controllers of bacterial population density in water systems. The goal of this study was to isolate and characterize V. cholerae-specific bacteriophages occurring in the Georgian coastal zone of the Black Sea and inland water reservoirs in the eastern part of Georgia. During 2006-2009, 71 phages lytic to V. cholerae were collected from these aquatic environments. The phage isolation rate was varying from 8% to 15%, depending on the sampling season and site, and the abundance of host bacteria. The majority of phages specific to V. cholerae were collected from freshwater sources. The phage isolation showed seasonal character covering warm period -from April to September. Based on basic characteristics of primary phage isolates (lytic spectrum, virion morphology and DNA restriction profiles) 23 V. cholerae -specific phages were selected for series of consecutive screenings. Comparatively wide spectrum of lytic activity was revealed in case of 14 phages specific to V. cholerae O1, and one phage - VchBS3, active against non-O1 V. cholerae. Three phages active against V. cholerae non-O1 and six V. cholerae O1 -specific phages have been studied in detail for a number of biological features (stability in different solutions, temperature-, pH- and UV- sensitivity, influence of high ionic strength etc.), considered to be additional important characteristics for selection of phages with therapeutic potential.

  4. Bacteriophages as Bactericides in Plant Protection

    Directory of Open Access Journals (Sweden)

    Aleksa Obradović

    2009-01-01

    Full Text Available Control of plant pathogenic bacteria is a serious problem in production of many agricultural crops. High multiplication rate, adaptability and life inside plant tissue make bacteria unsuitable and inaccessible for most of control measures. Consequently, the list of bactericides available for plant protection is very short. Lately, biological control measures have been intensively studied as a potential solution of the problem. Investigation of bacteriophages,viruses that attack bacteria, is a fast-expanding area of research in plant protection. Several experiments have shown that they can be used as a very efficient tool for control of plant pathogenic bacteria. The fact that they are widespread natural bacterial enemies, simple for cultivation and management, host-specific, suitable for integration with other control practices, human and environment friendly, provide a great advantage for the application of phages over other bactericides.

  5. Bacteriophage T7 DNA polymerase — Sequenase

    Directory of Open Access Journals (Sweden)

    Bin eZhu

    2014-04-01

    Full Text Available An ideal DNA polymerase for chain-terminating DNA sequencing should possess the following features: 1 incorporate dideoxy- and other modified nucleotides at an efficiency similar to that of the cognate deoxynucleotides; 2 high processivity; 3 high fidelity in the absence of proofreading/exonuclease activity; and 4 production of clear and uniform signals for detection. The DNA polymerase encoded by bacteriophage T7 is naturally endowed with or can be engineered to have all these characteristics. The chemically or genetically modified enzyme (Sequenase expedited significantly the development of DNA sequencing technology. This article reviews the history of studies on T7 DNA polymerase with emphasis on the serial key steps leading to its use in DNA sequencing. Lessons from the study and development of T7 DNA polymerase have and will continue to enlighten the characterization of novel DNA polymerases from newly discovered microbes and their modification for use in biotechnology.

  6. Bacteriophage endolysins: applications for food safety.

    Science.gov (United States)

    Schmelcher, Mathias; Loessner, Martin J

    2016-02-01

    Bacteriophage endolysins (peptidoglycan hydrolases) have emerged as a new class of antimicrobial agents useful for controlling bacterial infection or other unwanted contaminations in various fields, particularly in the light of the worldwide increasing frequency of drug-resistant pathogens. This review summarizes and discusses recent developments regarding the use of endolysins for food safety. Besides the use of native and engineered endolysins for controlling bacterial contamination at different points within the food production chain, this also includes the application of high-affinity endolysin-derived cell wall binding domains for rapid detection of pathogenic bacteria. Novel approaches to extend the lytic action of endolysins towards Gram-negative cells will also be highlighted.

  7. Why Be Temperate: Lessons from Bacteriophage λ.

    Science.gov (United States)

    Gandon, Sylvain

    2016-05-01

    Many pathogens have evolved the ability to induce latent infections of their hosts. The bacteriophage λ is a classical model for exploring the regulation and the evolution of latency. Here, I review recent experimental studies on phage λ that identify specific conditions promoting the evolution of lysogenic life cycles. In addition, I present specific adaptations of phage λ that allow this virus to react plastically to variations in the environment and to reactivate its lytic life cycle. All of these different examples are discussed in the light of evolutionary epidemiology theory to disentangle the different evolutionary forces acting on temperate phages. Understanding phage λ adaptations yield important insights into the evolution of latency in other microbes, including several life-threatening human pathogens. PMID:26946976

  8. Bacteriophages of Leuconostoc, Oenococcus and Weissella

    Directory of Open Access Journals (Sweden)

    Witold P. Kot

    2014-04-01

    Full Text Available Leuconostoc (Ln., Weissella and Oenococcus form a group of related genera of lactic acid bacteria, which once all shared the name Leuconostoc. They are associated with plants, fermented vegetable products, raw milk, dairy products, meat and fish. Most of industrially relevant Leuconostoc strains can be classified as either Ln. mesenteroides or Ln. pseudomesenteroides. They are important flavor producers in dairy fermentations and they initiate nearly all vegetable fermentations. Therefore bacteriophages attacking Leuconostoc strains may negatively influence the production process. Bacteriophages attacking Leuconostoc strains were first reported in 1946. Since then, the majority of described Leuconostoc phages was isolated from either dairy products or fermented vegetable products. Both lytic and temperate phages of Leuconostoc were reported. Most of Leuconostoc phages examined using electron microscopy belong to the Siphoviridae family and differ in morphological details. Hybridization and comparative genomic studies of Leuconostoc phages suggest that they can be divided into several groups, however overall diversity of Leuconostoc phages is much lower as compared to e.g. lactococcal phages. Several fully sequenced genomes of Leuconostoc phages have been deposited in public databases. Lytic phages of Leuconostoc can be divided into two host species-specific groups with similarly organized genomes that shared very low nucleotide similarity. Phages of dairy Leuconostoc have rather limited host-ranges. The receptor binding proteins of two lytic Ln. pseudomesenteroides phages have been identified. Molecular tools for detection of dairy Leuconostoc phages have been developed. The rather limited data on phages of Oenococcus and Weissella show that i lysogeny seems to be abundant in Oenococcus strains, and ii several phages infecting Weissella cibaria are also able to productively infect strains of other Weissella species and even strains of the genus

  9. Montmorillonite-induced Bacteriophage φ6 Disassembly

    Science.gov (United States)

    Trusiak, A.; Gottlieb, P.; Katz, A.; Alimova, A.; Steiner, J. C.; Block, K. A.

    2012-12-01

    It is estimated that there are 1031 virus particles on Earth making viruses an order of magnitude more prevalent in number than prokaryotes with the vast majority of viruses being bacteriophages. Clays are a major component of soils and aquatic sediments and can react with RNA, proteins and bacterial biofilms. The clays in soils serve as an important moderator between phage and their host bacteria, helping to preserve the evolutionary balance. Studies on the effects of clays on viral infectivity have given somewhat contradictory results; possibly a consequence of clay-virus interactions being dependent on the unique structure of particular viruses. In this work, the interaction between montmorillonite and the bacteriophage φ6 is investigated. φ6 is a member of the cystovirus family that infects Pseudomonas syringe, a common plant pathogen. As a member of the cystovirus family with an enveloped structure, φ6 serves as a model for reoviruses, a human pathogen. Experiments were conducted with φ6 suspended in dilute, purified homoionic commercial-grade montmorillonite over a range of virus:clay ratios. At a 1:100000 virus:clay ratio, the clay reduced viral infectivity by 99%. The minimum clay to virus ratio which results in a measurable reduction of P. syringae infection is 1:1. Electron microscopy demonstrates that mixed suspensions of smectite and virus co-aggregate to form flocs encompassing virions within the smectite. Both free viral particles as well as those imbedded in the flocs are seen in the micrographs to be missing the envelope- leaving only the nucleocapsid (NC) intact; indicating that smectite inactivates the virus by envelope disassembly. These results have strong implications in the evolution of both the φ6 virus and its P. syringae host cells. TEM of aggregate showing several disassembled NCs.

  10. A Hypothesis for Bacteriophage DNA Packaging Motors

    Directory of Open Access Journals (Sweden)

    Philip Serwer

    2010-08-01

    Full Text Available The hypothesis is presented that bacteriophage DNA packaging motors have a cycle comprised of bind/release thermal ratcheting with release-associated DNA pushing via ATP-dependent protein folding. The proposed protein folding occurs in crystallographically observed peptide segments that project into an axial channel of a protein 12-mer (connector that serves, together with a coaxial ATPase multimer, as the entry portal. The proposed cycle begins when reverse thermal motion causes the connector’s peptide segments to signal the ATPase multimer to bind both ATP and the DNA molecule, thereby producing a dwell phase recently demonstrated by single-molecule procedures. The connector-associated peptide segments activate by transfer of energy from ATP during the dwell. The proposed function of connector/ATPase symmetry mismatches is to reduce thermal noise-induced signaling errors. After a dwell, ATP is cleaved and the DNA molecule released. The activated peptide segments push the released DNA molecule, thereby producing a burst phase recently shown to consist of four mini-bursts. The constraint of four mini-bursts is met by proposing that each mini-burst occurs via pushing by three of the 12 subunits of the connector. If all four mini-bursts occur, the cycle repeats. If the mini-bursts are not completed, a second cycle is superimposed on the first cycle. The existence of the second cycle is based on data recently obtained with bacteriophage T3. When both cycles stall, energy is diverted to expose the DNA molecule to maturation cleavage.

  11. Felix aut infelix culpa

    OpenAIRE

    CHARLES MELMAN

    2004-01-01

    Hay faltas incontestablemente felices y otras que son insoportables. Dios perdona esta falta presente en la reproducción de la vida pero el asesinato no puede recibir perdón alguno. ¿Quién soy yo para pretender perdonar? Parece imponerse la venganza pero se ve venir la paradoja: verdugo y víctima resultarán ahora confundidos y hasta indiscernibles. Entonces, no hay que perdonar y olvidar porque es conveniente que la memoria conserve la historia de esos crímenes, ...

  12. The isolation and characterization of Campylobacter jejuni bacteriophages from free range and indoor poultry.

    Science.gov (United States)

    Owens, Jane; Barton, Mary D; Heuzenroeder, Michael W

    2013-02-22

    Six hundred and sixty one samples - primarily fresh chicken faeces - were processed to isolate wild type Campylobacter jejuni bacteriophages, via overlay agar methods using C. jejuni NCTC 12662. The aims of this study were to isolate and purify bacteriophages and then test for their ability to lyse field strains of C. jejuni in vitro. Of all samples processed, 130 were positive for bacteriophages. A distinct difference was observed between samples from different poultry enterprises. No bacteriophages could be isolated from indoor broilers. The majority of bacteriophages were isolated from free range poultry - both broilers and egg layers. Bacteriophages were purified and then selected for characterization based on their ability to produce clear lysis on plaque assay, as opposed to turbid plaques. Two hundred and forty one C. jejuni field isolates were tested for sensitivity to the bacteriophages. Lysis was graded subjectively and any minimal lysis was excluded. Using this system, 59.0% of the C. jejuni isolates showed significant sensitivity to at least one bacteriophage. The sensitivity to individual bacteriophages ranged from 10.0% to 32.5% of the C. jejuni isolates. Five bacteriophages were examined by electron microscopy and determined to belong to the Myoviridae family. The physical size, predicted genetic composition and genome size of the bacteriophages correlated well with other reported Campylobacter bacteriophages. The reasons for the observed difference between indoor broilers and free range poultry is unknown, but are postulated to be due to differences in the Campylobacter population in birds under different rearing conditions.

  13. Bacteriophage therapy for safeguarding animal and human health: a review.

    Science.gov (United States)

    Tiwari, Ruchi; Dhama, Kuldeep; Kumar, Amit; Rahal, Anu; Kapoor, Sanjay

    2014-02-01

    Since the discovery of bacteriophages at the beginning of the 19th century their contribution to bacterial evolution and ecology and use in a variety of applications in biotechnology and medicine has been recognized and understood. Bacteriophages are natural bacterial killers, proven as best biocontrol agents due to their ability to lyse host bacterial cells specifically thereby helping in disease prevention and control. The requirement of such therapeutic approach is straight away required in view of the global emergence of Multidrug Resistant (MDR) strains of bacteria and rapidly developing resistance to antibiotics in both animals and humans along with increasing food safety concerns including of residual antibiotic toxicities. Phage typing is a popular tool to differentiate bacterial isolates and to identify and characterize outbreak-associated strains of Salmonella, Campylobacter, Escherichia and Listeria. Numerous methods viz. plaque morphology, ultracentrifugation in the density gradient of CsCl2, and random amplified polymorphic DNA (RAPD) have been found to be effective in detection of various phages. Bacteriophages have been isolated and recovered from samples of animal waste products of different livestock farms. High titer cocktails of broad spectrum lytic bacteriophages are usually used for clinical trial for assessing their therapeutic efficacy against antibiotic unresponsive infections in different animals. Bacteriophage therapy also helps to fight various bacterial infections of poultry viz. colibacillosis, salmonellosis and listeriosis. Moreover, the utility of phages concerning biosafety has raised the importance to explore and popularize the therapeutic dimension of this promising novel therapy which forms the topic of discussion of the present review.

  14. Bacteriophages as an alternative strategy for fighting biofilm development.

    Science.gov (United States)

    Parasion, Sylwia; Kwiatek, Magdalena; Gryko, Romuald; Mizak, Lidia; Malm, Anna

    2014-01-01

    The ability of microbes to form biofilms is an important element of their pathogenicity, and biofilm formation is a serious challenge for today's medicine. Fighting the clinical complications associated with biofilm formation is very difficult and linked to a high risk of failure, especially in a time of increasing bacterial resistance to antibiotics. Bacterial species most commonly isolated from biofilms include coagulase-negative staphylococci, Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter spp. The frequent failure of antibiotic therapy led researchers to look for alternative methods and experiment with the use of antibacterial factors with a mechanism of action different from that of antibiotics. Experimental studies with bacteriophages and mixtures thereof, expressing lytic properties against numerous biofilm-forming bacterial species showed that bacteriophages may both prevent biofilm formation and contribute to eradication of biofilm bacteria. A specific role is played here by phage depolymerases, which facilitate the degradation of extracellular polymeric substances (EPS) and thus the permeation of bacteriophages into deeper biofilm layers and lysis of the susceptible bacterial cells. Much hope is placed in genetic modifications of bacteriophages that would allow the equipping bacteriophages with the function of depolymerase synthesis. The use of phage cocktails prevents the development of phage-resistant bacteria.

  15. Alternative bacteriophage life cycles: the carrier state of Campylobacter jejuni.

    Science.gov (United States)

    Siringan, Patcharin; Connerton, Phillippa L; Cummings, Nicola J; Connerton, Ian F

    2014-01-01

    Members of the genus Campylobacter are frequently responsible for human enteric disease, often through consumption of contaminated poultry products. Bacteriophages are viruses that have the potential to control pathogenic bacteria, but understanding their complex life cycles is key to their successful exploitation. Treatment of Campylobacter jejuni biofilms with bacteriophages led to the discovery that phages had established a relationship with their hosts typical of the carrier state life cycle (CSLC), where bacteria and bacteriophages remain associated in equilibrium. Significant phenotypic changes include improved aerotolerance under nutrient-limited conditions that would confer an advantage to survive in extra-intestinal environments, but a lack in motility eliminated their ability to colonize chickens. Under these circumstances, phages can remain associated with a compatible host and continue to produce free virions to prospect for new hosts. Moreover, we demonstrate that CSLC host bacteria can act as expendable vehicles for the delivery of bacteriophages to new host bacteria within pre-colonized chickens. The CSLC represents an important phase in the ecology of Campylobacter bacteriophage. PMID:24671947

  16. Sequence variability of Campylobacter temperate bacteriophages

    Directory of Open Access Journals (Sweden)

    Ng Lai-King

    2008-03-01

    Full Text Available Abstract Background Prophages integrated within the chromosomes of Campylobacter jejuni isolates have been demonstrated very recently. Prior work with Campylobacter temperate bacteriophages, as well as evidence from prophages in other enteric bacteria, suggests these prophages might have a role in the biology and virulence of the organism. However, very little is known about the genetic variability of Campylobacter prophages which, if present, could lead to differential phenotypes in isolates carrying the phages versus those that do not. As a first step in the characterization of C. jejuni prophages, we investigated the distribution of prophage DNA within a C. jejuni population assessed the DNA and protein sequence variability within a subset of the putative prophages found. Results Southern blotting of C. jejuni DNA using probes from genes within the three putative prophages of the C. jejuni sequenced strain RM 1221 demonstrated the presence of at least one prophage gene in a large proportion (27/35 of isolates tested. Of these, 15 were positive for 5 or more of the 7 Campylobacter Mu-like phage 1 (CMLP 1, also designated Campylobacter jejuni integrated element 1, or CJIE 1 genes tested. Twelve of these putative prophages were chosen for further analysis. DNA sequencing of a 9,000 to 11,000 nucleotide region of each prophage demonstrated a close homology with CMLP 1 in both gene order and nucleotide sequence. Structural and sequence variability, including short insertions, deletions, and allele replacements, were found within the prophage genomes, some of which would alter the protein products of the ORFs involved. No insertions of novel genes were detected within the sequenced regions. The 12 prophages and RM 1221 had a % G+C very similar to C. jejuni sequenced strains, as well as promoter regions characteristic of C. jejuni. None of the putative prophages were successfully induced and propagated, so it is not known if they were functional or

  17. Bacteriophage based probes for pathogen detection.

    Science.gov (United States)

    Singh, Amit; Arutyunov, Denis; Szymanski, Christine M; Evoy, Stephane

    2012-08-01

    Rapid and specific detection of pathogenic bacteria is important for the proper treatment, containment and prevention of human, animal and plant diseases. Identifying unique biological probes to achieve a high degree of specificity and minimize false positives has therefore garnered much interest in recent years. Bacteriophages are obligate intracellular parasites that subvert bacterial cell resources for their own multiplication and production of disseminative new virions, which repeat the cycle by binding specifically to the host surface receptors and injecting genetic material into the bacterial cells. The precision of host recognition in phages is imparted by the receptor binding proteins (RBPs) that are often located in the tail-spike or tail fiber protein assemblies of the virions. Phage host recognition specificity has been traditionally exploited for bacterial typing using laborious and time consuming bacterial growth assays. At the same time this feature makes phage virions or RBPs an excellent choice for the development of probes capable of selectively capturing bacteria on solid surfaces with subsequent quick and automatic detection of the binding event. This review focuses on the description of pathogen detection approaches based on immobilized phage virions as well as pure recombinant RBPs. Specific advantages of RBP-based molecular probes are also discussed.

  18. Interplay Between Bacteriophages and Restriction-Modification Systems in Enterococci

    Directory of Open Access Journals (Sweden)

    Pristas Peter

    2014-06-01

    Full Text Available The complete genomes of Enterococcus faecalis bacteriophages were analyzed for tetranucleotide words avoidance. Very similar tetranucleotide composition was found in all tested genomes with strong underrepresentation of palindromic GATC and GGCC words. This avoidance could be explained as a protection mechanism against host restriction-modification systems as a clear correlation was found between avoidance of palindromic words and the specificity of E. faecalis restriction and modification systems. No similar avoidance of tetranucleotide words was observed for non-palindromic words. A weak correlation was observed between avoidance of tetranucleotide palindromes in bacteriophage genomes and the possession of phage encoded DNA methyltransferases confirming the interrelation between bacteriophage genomes composition and restriction and modification systems in enterococci

  19. A quorum-sensing-induced bacteriophage defense mechanism

    DEFF Research Database (Denmark)

    Høyland-Kroghsbo, Nina Molin; Mærkedahl, Rasmus Baadsgaard; Svenningsen, Sine

    2013-01-01

    One of the key determinants of the size, composition, structure, and development of a microbial community is the predation pressure by bacteriophages. Accordingly, bacteria have evolved a battery of antiphage defense strategies. Since maintaining constantly elevated defenses is costly, we...... understanding of the factors that naturally shape microbial communities is required. One of the key factors in this context is the interactions between bacteria and the most abundant biological entities on Earth, namely, the bacteriophages that prey on bacteria. This proof-of-principle study shows that quorum...... sensing plays an important role in determining the susceptibility of E. coli to infection by bacteriophages ¿ and ¿. On the basis of our findings in the classical Escherichia coli-¿ model system, we suggest that quorum sensing may serve as a general strategy to protect bacteria specifically under...

  20. Bacteriophages as potential treatment option for antibiotic resistant bacteria.

    Science.gov (United States)

    Bragg, Robert; van der Westhuizen, Wouter; Lee, Ji-Yun; Coetsee, Elke; Boucher, Charlotte

    2014-01-01

    The world is facing an ever-increasing problem with antibiotic resistant bacteria and we are rapidly heading for a post-antibiotic era. There is an urgent need to investigate alterative treatment options while there are still a few antibiotics left. Bacteriophages are viruses that specifically target bacteria. Before the development of antibiotics, some efforts were made to use bacteriophages as a treatment option, but most of this research stopped soon after the discovery of antibiotics. There are two different replication options which bacteriophages employ. These are the lytic and lysogenic life cycles. Both these life cycles have potential as treatment options. There are various advantages and disadvantages to the use of bacteriophages as treatment options. The main advantage is the specificity of bacteriophages and treatments can be designed to specifically target pathogenic bacteria while not negatively affecting the normal microbiota. There are various advantages to this. However, the high level of specificity also creates potential problems, the main being the requirement of highly specific diagnostic procedures. Another potential problem with phage therapy includes the development of immunity and limitations with the registration of phage therapy options. The latter is driving research toward the expression of phage genes which break the bacterial cell wall, which could then be used as a treatment option. Various aspects of phage therapy have been investigated in studies undertaken by our research group. We have investigated specificity of phages to various avian pathogenic E. coli isolates. Furthermore, the exciting NanoSAM technology has been employed to investigate bacteriophage replication and aspects of this will be discussed.

  1. Bacteriophages as potential treatment option for antibiotic resistant bacteria.

    Science.gov (United States)

    Bragg, Robert; van der Westhuizen, Wouter; Lee, Ji-Yun; Coetsee, Elke; Boucher, Charlotte

    2014-01-01

    The world is facing an ever-increasing problem with antibiotic resistant bacteria and we are rapidly heading for a post-antibiotic era. There is an urgent need to investigate alterative treatment options while there are still a few antibiotics left. Bacteriophages are viruses that specifically target bacteria. Before the development of antibiotics, some efforts were made to use bacteriophages as a treatment option, but most of this research stopped soon after the discovery of antibiotics. There are two different replication options which bacteriophages employ. These are the lytic and lysogenic life cycles. Both these life cycles have potential as treatment options. There are various advantages and disadvantages to the use of bacteriophages as treatment options. The main advantage is the specificity of bacteriophages and treatments can be designed to specifically target pathogenic bacteria while not negatively affecting the normal microbiota. There are various advantages to this. However, the high level of specificity also creates potential problems, the main being the requirement of highly specific diagnostic procedures. Another potential problem with phage therapy includes the development of immunity and limitations with the registration of phage therapy options. The latter is driving research toward the expression of phage genes which break the bacterial cell wall, which could then be used as a treatment option. Various aspects of phage therapy have been investigated in studies undertaken by our research group. We have investigated specificity of phages to various avian pathogenic E. coli isolates. Furthermore, the exciting NanoSAM technology has been employed to investigate bacteriophage replication and aspects of this will be discussed. PMID:24619620

  2. 26 CFR 31.3121(o)-1 - Crew leader.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 15 2010-04-01 2010-04-01 false Crew leader. 31.3121(o)-1 Section 31.3121(o)-1... Contributions Act (Chapter 21, Internal Revenue Code of 1954) General Provisions § 31.3121(o)-1 Crew leader. The term “crew leader” means an individual who furnishes individuals to perform agricultural labor...

  3. Bacteriophages of Soft Rot Enterobacteriaceae-a minireview.

    Science.gov (United States)

    Czajkowski, Robert

    2016-01-01

    Soft rot Enterobacteriaceae (Pectobacterium spp. and Dickeya spp., formerly pectinolytic Erwinia spp.) are ubiquitous necrotrophic bacterial pathogens that infect a large number of different plant species worldwide, including economically important crops. Despite the fact that these bacteria have been studied for more than 50 years, little is known of their corresponding predators: bacteriophages, both lytic and lysogenic. The aim of this minireview is to critically summarize recent ecological, biological and molecular research on bacteriophages infecting Pectobacterium spp. and Dickeya spp. with the main focus on current and future perspectives in that field.

  4. Engineered enzymatically active bacteriophages and methods of uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Collins, James J (Newton, MA); Kobayashi, Hideki (Yokohama, JP); Kearn, Mads (Ottawa, CA); Araki, Michihiro (Minatoku, JP); Friedland, Ari (Boston, MA); Lu, Timothy Kuan-Ta (Palo Alto, CA)

    2012-05-22

    The present invention provides engineered bacteriophages that express at least one biofilm degrading enzyme on their surface and uses thereof for degrading bacterial biofilms. The invention also provides genetically engineered bacteriophages expressing the biofilm degrading enzymes and proteins necessary for the phage to replicate in different naturally occurring biofilm producing bacteria. The phages of the invention allow a method of biofilm degradation by the use of one or only a few administration of the phage because the system using these phages is self perpetuating, and capable of degrading biofilm even when the concentration of bacteria within the biofilm is low.

  5. Molecular and chemical engineering of bacteriophages for potential medical applications.

    Science.gov (United States)

    Hodyra, Katarzyna; Dąbrowska, Krystyna

    2015-04-01

    Recent progress in molecular engineering has contributed to the great progress of medicine. However, there are still difficult problems constituting a challenge for molecular biology and biotechnology, e.g. new generation of anticancer agents, alternative biosensors or vaccines. As a biotechnological tool, bacteriophages (phages) offer a promising alternative to traditional approaches. They can be applied as anticancer agents, novel platforms in vaccine design, or as target carriers in drug discovery. Phages also offer solutions for modern cell imaging, biosensor construction or food pathogen detection. Here we present a review of bacteriophage research as a dynamically developing field with promising prospects for further development of medicine and biotechnology.

  6. Salmonella and Campylobacter: Antimicrobial resistance and bacteriophage control in poultry.

    Science.gov (United States)

    Grant, Ar'Quette; Hashem, Fawzy; Parveen, Salina

    2016-02-01

    Salmonella and Campylobacter are major causes of foodborne related illness and are traditionally associated with consuming undercooked poultry and/or consuming products that have been cross contaminated with raw poultry. Many of the isolated Salmonella and Campylobacter that can cause disease have displayed antimicrobial resistance phenotypes. Although poultry producers have reduced on-the-farm overuse of antimicrobials, antimicrobial resistant Salmonella and Campylobacter strains still persist. One method of bio-control, that is producing promising results, is the use of lytic bacteriophages. This review will highlight the current emergence and persistence of antimicrobial resistant Salmonella and Campylobacter recovered from poultry as well as bacteriophage research interventions and limitations.

  7. Mechanism of bacteriophage conversion of lipase activity in Staphylococcus aureus.

    OpenAIRE

    Lee, C Y; Iandolo, J J

    1985-01-01

    Staphylococcus aureus PS54 harbors two temperate bacteriophages and manifests no lipase activity on egg yolk agar. Curing of one of the resident prophages (L54a) restores lipase activity. To study the mechanism of bacteriophage conversion, the prophage was cured, and the gene encoding lipase activity was cloned into pBR322 in Escherichia coli on a 2.9-kilobase DNA fragment of the chromosome. The fragment was subcloned into a shuttle vector and subsequently transformed into S. aureus and Bacil...

  8. Environmental augmentation with bacteriophage prevents colibacillosis in broiler chickens.

    Science.gov (United States)

    El-Gohary, F A; Huff, W E; Huff, G R; Rath, N C; Zhou, Z Y; Donoghue, A M

    2014-11-01

    Bacteriophages are viruses that kill bacteria. They are plentiful in nature; are safe, having no known activity to human or animal cells; and are an attractive alternative to antibiotics. The objectives of this research were to establish an experimental model of colibacillosis induced by indirect exposure to Escherichia coli and to determine if bacteriophage could protect the birds from developing colibacillosis. In study 1 there were 6 treatments with 2 replicate pens of 25 birds. The treatments were control warm brooded; control cold stressed; litter inoculated with E. coli, warm brooded; litter inoculated with E. coli, cold stressed; seeder birds (5 per pen) challenged with E. coli, warm brooded; and seeder birds (5 per pen), cold stressed. The study concluded when the birds were 3 wk of age. Body weights at 1, 2, and 3 wk of age were significantly decreased (P ≤ 0.05) by cold stress, decreased at 1 and 2 wk of age by both the litter and seeder bird treatments compared with the control treatment and by the seeder bird treatment at 3 wk of age. Study 2 consisted of 8 treatments with 2 replicate pens of 20 birds per treatment. The treatments were control, warm brooded; control, cold stressed; litter inoculated with E. coli, cold stressed; and seeder birds (5/pen) challenged with E. coli, cold stressed with and without bacteriophage treatment. In the bacteriophage treatments the bacteriophages were sprayed on the litter. The study was concluded at 3 wk of age. Body weights at 1 wk of age were significantly (P ≤ 0.05) decreased from the control treatment by the seeder bird treatment and were significantly (P ≤ 0.05) higher in all the bacteriophage treatments compared with their matched untreated treatments, except in the control cold stressed treatment. Mortality was significantly (P ≤ 0.05) decreased by bacteriophage in the litter challenged treatment. These data suggest that augmentation of the environment with bacteriophage is a practical and efficacious

  9. Norovirus and FRNA bacteriophage determined by RT-qPCR and infectious FRNA bacteriophage in wastewater and oysters.

    Science.gov (United States)

    Flannery, John; Keaveney, Sinéad; Rajko-Nenow, Paulina; O'Flaherty, Vincent; Doré, William

    2013-09-15

    Norovirus (NoV), the leading cause of adult non-bacterial gastroenteritis can be commonly detected in wastewater but the extent of NoV removal provided by wastewater treatment plants (WWTPs) is unclear. We monitored a newly commissioned WWTP with UV disinfection on a weekly basis over a six month period for NoV using RT-qPCR and for FRNA bacteriophage GA using both RT-qPCR (total concentration) and a plaque assay (infectious concentration). Mean concentrations of NoV GI and GII in influent wastewater were reduced by 0.25 and 0.41 log10 genome copies 100 ml(-1), respectively by the WWTP. The mean concentration of total FRNA bacteriophage GA was reduced by 0.35 log genome copies 100 ml(-1) compared to a reduction of infectious FRNA bacteriophage GA of 2.13 log PFU 100 ml(-1). A significant difference between concentrations of infectious and total FRNA bacteriophage GA was observed in treated, but not in untreated wastewaters. We conclude that RT-qPCR in isolation underestimates the reduction of infectious virus during wastewater treatment. We further compared the concentrations of infectious virus in combined sewer overflow (CSO) and UV treated effluents using FRNA bacteriophage GA. A greater percentage (98%) of infectious virus is released in CSO discharges than UV treated effluent (44%). Following a CSO discharge, concentrations of NoV GII and infectious FRNA bacteriophage GA in oysters from less than the limit of detection to 3150 genome copies 100 g(-1) and 1050 PFU 100 g(-1) respectively.

  10. Novel bacteriophages containing a genome of another bacteriophage within their genomes.

    Directory of Open Access Journals (Sweden)

    Maud M Swanson

    Full Text Available A novel bacteriophage infecting Staphylococus pasteuri was isolated during a screen for phages in Antarctic soils. The phage named SpaA1 is morphologically similar to phages of the family Siphoviridae. The 42,784 bp genome of SpaA1 is a linear, double-stranded DNA molecule with 3' protruding cohesive ends. The SpaA1 genome encompasses 63 predicted protein-coding genes which cluster within three regions of the genome, each of apparently different origin, in a mosaic pattern. In two of these regions, the gene sets resemble those in prophages of Bacillus thuringiensis kurstaki str. T03a001 (genes involved in DNA replication/transcription, cell entry and exit and B. cereus AH676 (additional regulatory and recombination genes, respectively. The third region represents an almost complete genome (except for the short terminal segments of a distinct bacteriophage, MZTP02. Nearly the same gene module was identified in prophages of B. thuringiensis serovar monterrey BGSC 4AJ1 and B. cereus Rock4-2. These findings suggest that MZTP02 can be shuttled between genomes of other bacteriophages and prophages, leading to the formation of chimeric genomes. The presence of a complete phage genome in the genome of other phages apparently has not been described previously and might represent a 'fast track' route of virus evolution and horizontal gene transfer. Another phage (BceA1 nearly identical in sequence to SpaA1, and also including the almost complete MZTP02 genome within its own genome, was isolated from a bacterium of the B. cereus/B. thuringiensis group. Remarkably, both SpaA1 and BceA1 phages can infect B. cereus and B. thuringiensis, but only one of them, SpaA1, can infect S. pasteuri. This finding is best compatible with a scenario in which MZTP02 was originally contained in BceA1 infecting Bacillus spp, the common hosts for these two phages, followed by emergence of SpaA1 infecting S. pasteuri.

  11. Immobilization of Active Bacteriophages on Polyhydroxyalkanoate Surfaces.

    Science.gov (United States)

    Wang, Chanchan; Sauvageau, Dominic; Elias, Anastasia

    2016-01-20

    A rapid, efficient technique for the attachment of bacteriophages (phages) onto polyhydroxyalkanoate (PHA) surfaces has been developed and compared to three reported methods for phage immobilization. Polymer surfaces were modified to facilitate phage attachment using (1) plasma treatment alone, (2) plasma treatment followed by activation by 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide (sulfo-NHS), (3) plasma-initiated acrylic acid grafting, or (4) plasma-initiated acrylic acid grafting with activation by EDC and sulfo-NHS. The impact of each method on the surface chemistry of PHA was investigated using contact angle analysis and X-ray photoelectron spectroscopy. Each of the four treatments was shown to result in both increased hydrophilicity and in the modification of the surface functional groups. Modified surfaces were immersed in suspensions of phage T4 for immobilization. The highest level of phage binding was observed for the surfaces modified by plasma treatment alone. The change in chemical bond states observed for surfaces that underwent plasma treatment is suspected to be the cause of the increased binding of active phages. Plasma-treated surfaces were further analyzed through phage-staining and fluorescence microscopy to assess the surface density of immobilized phages and their capacity to capture hosts. The infective capability of attached phages was confirmed by exposing the phage-immobilized surfaces to the host bacteria Escherichia coli in both plaque and infection dynamic assays. Plasma-treated surfaces with immobilized phages displayed higher infectivity than surfaces treated with other methods; in fact, the equivalent initial multiplicity of infection was 2 orders of magnitude greater than with other methods. Control samples - prepared by immersing polymer surfaces in phage suspensions (without prior plasma treatment) - did not show any bacterial growth inhibition, suggesting they did not bind

  12. Effects of bacteriophage traits on plaque formation

    Directory of Open Access Journals (Sweden)

    Kannoly Sherin

    2011-08-01

    Full Text Available Abstract Background The appearance of plaques on a bacterial lawn is one of the enduring imageries in modern day biology. The seeming simplicity of a plaque has invited many hypotheses and models in trying to describe and explain the details of its formation. However, until now, there has been no systematic experimental exploration on how different bacteriophage (phage traits may influence the formation of a plaque. In this study, we constructed a series of isogenic λ phages that differ in their adsorption rate, lysis timing, or morphology so that we can determine the effects if these changes on three plaque properties: size, progeny productivity, and phage concentration within plaques. Results We found that the adsorption rate has a diminishing, but negative impact on all three plaque measurements. Interestingly, there exists a concave relationship between the lysis time and plaque size, resulting in an apparent optimal lysis time that maximizes the plaque size. Although suggestive in appearance, we did not detect a significant effect of lysis time on plaque productivity. Nonetheless, the combined effects of plaque size and productivity resulted in an apparent convex relationship between the lysis time and phage concentration within plaques. Lastly, we found that virion morphology also affected plaque size. We compared our results to the available models on plaque size and productivity. For the models in their current forms, a few of them can capture the qualitative aspects of our results, but not consistently in both plaque properties. Conclusions By using a collection of isogenic phage strains, we were able to investigate the effects of individual phage traits on plaque size, plaque productivity, and average phage concentration in a plaque while holding all other traits constant. The controlled nature of our study allowed us to test several model predictions on plaque size and plaque productivity. It seems that a more realistic theoretical

  13. STUDIES ON THE BACTERIOPHAGE OF D'HERELLE : VII. ON THE PARTICULATE NATURE OF BACTERIOPHAGE.

    Science.gov (United States)

    Bronfenbrenner, J

    1927-04-30

    When filtrates of lysed cultures (bacteriophage) are subjected to prolonged dialysis under osmotic pressure against water, the presence of the lytic agent can be detected outside the membrane only during the first few days. The residue remaining inside the membrane contains the bulk of the original lytic agent, and yet it is no longer capable of diffusing into the outer solution. The interruption of diffusion is shown not to be due to any alteration in the permeability of the membrane. Moreover, the residue fails to diffuse through a fresh membrane of similar permeability, while the dialyzed portion of the phage passes quantitatively through a new membrane. When ultrafiltration under pressure was substituted for dialysis, the residue on the filter could be washed repeatedly with water without giving off into the filtrate any more active agent. However, if broth was substituted for water, a renewed diffusion of the active agent resulted. These results are interpreted as indicating that the colloidal particles present in the lytic filtrates (and apparently endowed with properties of bacteriophage) do not represent autonomous units of the active agent, but merely serve as a vehicle on which the agent is adsorbed. The vary in size within limits wide enough to permit fractionation by means of ultrafiltration. When the coarser particles retained by the ultrafilter are washed with broth, some of the active agent is detached from its coarse vehicle particles. The agent, now more highly dispersed, is capable of passing the filter which held it back previously. Preparation of a simple ultrafilter used in these experiments is given in detail.

  14. More Is Better: Selecting for Broad Host Range Bacteriophages.

    Science.gov (United States)

    Ross, Alexa; Ward, Samantha; Hyman, Paul

    2016-01-01

    Bacteriophages are viruses that infect bacteria. In this perspective, we discuss several aspects of a characteristic feature of bacteriophages, their host range. Each phage has its own particular host range, the range of bacteria that it can infect. While some phages can only infect one or a few bacterial strains, other phages can infect many species or even bacteria from different genera. Different methods for determining host range may give different results, reflecting the multiple mechanisms bacteria have to resist phage infection and reflecting the different steps of infection each method depends on. This makes defining host range difficult. Another difficulty in describing host range arises from the inconsistent use of the words "narrow" and especially "broad" when describing the breadth of the host range. Nearly all bacteriophages have been isolated using a single host strain of bacteria. While this procedure is fairly standard, it may more likely produce narrow rather than broad host range phage. Our results and those of others suggest that using multiple host strains during isolation can more reliably produce broader host range phages. This challenges the common belief that most bacteriophages have a narrow host range. We highlight the implications of this for several areas that are affected by host range including horizontal gene transfer and phage therapy. PMID:27660623

  15. Bacteriophage for prophylaxis and therapy in cattle, poultry, and pigs.

    Science.gov (United States)

    The successful use of virulent (lytic) bacteriophages (phages) in preventing and treating neonatal enterotoxigenic Escherichia coli infections in calves, lambs and pigs has prompted investigation of other applications phage therapy in food animals. While results have been very variable, some indica...

  16. Genome Sequences of Gordonia terrae Bacteriophages Phinally and Vivi2.

    Science.gov (United States)

    Pope, Welkin H; Anderson, Kaitlyn C; Arora, Charu; Bortz, Michael E; Burnet, George; Conover, David H; D'Incau, Gina M; Ghobrial, Jonathan A; Jonas, Audrey L; Migdal, Emily J; Rote, Nicole L; German, Brian A; McDonnell, Jill E; Mezghani, Nadia; Schafer, Claire E; Thompson, Paige K; Ulbrich, Megan C; Yu, Victor J; Furbee, Emily C; Grubb, Sarah R; Warner, Marcie H; Montgomery, Matthew T; Garlena, Rebecca A; Russell, Daniel A; Jacobs-Sera, Deborah; Hatfull, Graham F

    2016-08-18

    Bacteriophages Phinally and Vivi2 were isolated from soil from Pittsburgh, Pennsylvania, USA, using host Gordonia terrae 3612. The Phinally and Vivi2 genomes are 59,265 bp and 59,337 bp, respectively, and share sequence similarity with each other and with GTE6. Fewer than 25% of the 87 to 89 putative genes have predictable functions.

  17. Bacteriophages Limit the Existence Conditions for Conjugative Plasmids

    Science.gov (United States)

    Wood, A. Jamie; Dytham, Calvin; Pitchford, Jonathan W.; Truman, Julie; Spiers, Andrew; Paterson, Steve; Brockhurst, Michael A.

    2015-01-01

    ABSTRACT Bacteriophages are a major cause of bacterial mortality and impose strong selection on natural bacterial populations, yet their effects on the dynamics of conjugative plasmids have rarely been tested. We combined experimental evolution, mathematical modeling, and individual-based simulations to explain how the ecological and population genetics effects of bacteriophages upon bacteria interact to determine the dynamics of conjugative plasmids and their persistence. The ecological effects of bacteriophages on bacteria are predicted to limit the existence conditions for conjugative plasmids, preventing persistence under weak selection for plasmid accessory traits. Experiments showed that phages drove faster extinction of plasmids in environments where the plasmid conferred no benefit, but they also revealed more complex effects of phages on plasmid dynamics under these conditions, specifically, the temporary maintenance of plasmids at fixation followed by rapid loss. We hypothesized that the population genetic effects of bacteriophages, specifically, selection for phage resistance mutations, may have caused this. Further mathematical modeling and individual-based simulations supported our hypothesis, showing that conjugative plasmids may hitchhike with phage resistance mutations in the bacterial chromosome. PMID:26037122

  18. More Is Better: Selecting for Broad Host Range Bacteriophages.

    Science.gov (United States)

    Ross, Alexa; Ward, Samantha; Hyman, Paul

    2016-01-01

    Bacteriophages are viruses that infect bacteria. In this perspective, we discuss several aspects of a characteristic feature of bacteriophages, their host range. Each phage has its own particular host range, the range of bacteria that it can infect. While some phages can only infect one or a few bacterial strains, other phages can infect many species or even bacteria from different genera. Different methods for determining host range may give different results, reflecting the multiple mechanisms bacteria have to resist phage infection and reflecting the different steps of infection each method depends on. This makes defining host range difficult. Another difficulty in describing host range arises from the inconsistent use of the words "narrow" and especially "broad" when describing the breadth of the host range. Nearly all bacteriophages have been isolated using a single host strain of bacteria. While this procedure is fairly standard, it may more likely produce narrow rather than broad host range phage. Our results and those of others suggest that using multiple host strains during isolation can more reliably produce broader host range phages. This challenges the common belief that most bacteriophages have a narrow host range. We highlight the implications of this for several areas that are affected by host range including horizontal gene transfer and phage therapy.

  19. Complete Genome Sequence of Bacillus thuringiensis Bacteriophage Smudge.

    Science.gov (United States)

    Cornell, Jessica L; Breslin, Eileen; Schuhmacher, Zachary; Himelright, Madison; Berluti, Cassandra; Boyd, Charles; Carson, Rachel; Del Gallo, Elle; Giessler, Caris; Gilliam, Benjamin; Heatherly, Catherine; Nevin, Julius; Nguyen, Bryan; Nguyen, Justin; Parada, Jocelyn; Sutterfield, Blake; Tukruni, Muruj; Temple, Louise

    2016-01-01

    Smudge, a bacteriophage enriched from soil using Bacillus thuringiensis DSM-350 as the host, had its complete genome sequenced. Smudge is a myovirus with a genome consisting of 292 genes and was identified as belonging to the C1 cluster of Bacillus phages. PMID:27540049

  20. Complete Genome Sequence of Bacillus thuringiensis Bacteriophage Smudge

    Science.gov (United States)

    Cornell, Jessica L.; Breslin, Eileen; Schuhmacher, Zachary; Himelright, Madison; Berluti, Cassandra; Boyd, Charles; Carson, Rachel; Del Gallo, Elle; Giessler, Caris; Gilliam, Benjamin; Heatherly, Catherine; Nevin, Julius; Nguyen, Bryan; Nguyen, Justin; Parada, Jocelyn; Sutterfield, Blake; Tukruni, Muruj

    2016-01-01

    Smudge, a bacteriophage enriched from soil using Bacillus thuringiensis DSM-350 as the host, had its complete genome sequenced. Smudge is a myovirus with a genome consisting of 292 genes and was identified as belonging to the C1 cluster of Bacillus phages. PMID:27540049

  1. Complete Genome Sequence of Bacillus thuringiensis Bacteriophage Smudge.

    Science.gov (United States)

    Cornell, Jessica L; Breslin, Eileen; Schuhmacher, Zachary; Himelright, Madison; Berluti, Cassandra; Boyd, Charles; Carson, Rachel; Del Gallo, Elle; Giessler, Caris; Gilliam, Benjamin; Heatherly, Catherine; Nevin, Julius; Nguyen, Bryan; Nguyen, Justin; Parada, Jocelyn; Sutterfield, Blake; Tukruni, Muruj; Temple, Louise

    2016-08-18

    Smudge, a bacteriophage enriched from soil using Bacillus thuringiensis DSM-350 as the host, had its complete genome sequenced. Smudge is a myovirus with a genome consisting of 292 genes and was identified as belonging to the C1 cluster of Bacillus phages.

  2. Role of osmotic and hydrostatic pressures in bacteriophage genome ejection

    NARCIS (Netherlands)

    Lemay, S.G.; Panja, D.; Molineux, I.J.

    2013-01-01

    A critical step in the bacteriophage life cycle is genome ejection into host bacteria. The ejection process for double-stranded DNA phages has been studied thoroughly in vitro, where after triggering with the cellular receptor the genome ejects into a buffer. The experimental data have been interpre

  3. More Is Better: Selecting for Broad Host Range Bacteriophages

    Science.gov (United States)

    Ross, Alexa; Ward, Samantha; Hyman, Paul

    2016-01-01

    Bacteriophages are viruses that infect bacteria. In this perspective, we discuss several aspects of a characteristic feature of bacteriophages, their host range. Each phage has its own particular host range, the range of bacteria that it can infect. While some phages can only infect one or a few bacterial strains, other phages can infect many species or even bacteria from different genera. Different methods for determining host range may give different results, reflecting the multiple mechanisms bacteria have to resist phage infection and reflecting the different steps of infection each method depends on. This makes defining host range difficult. Another difficulty in describing host range arises from the inconsistent use of the words “narrow” and especially “broad” when describing the breadth of the host range. Nearly all bacteriophages have been isolated using a single host strain of bacteria. While this procedure is fairly standard, it may more likely produce narrow rather than broad host range phage. Our results and those of others suggest that using multiple host strains during isolation can more reliably produce broader host range phages. This challenges the common belief that most bacteriophages have a narrow host range. We highlight the implications of this for several areas that are affected by host range including horizontal gene transfer and phage therapy. PMID:27660623

  4. Multiple roles of genome-attached bacteriophage terminal proteins

    Energy Technology Data Exchange (ETDEWEB)

    Redrejo-Rodríguez, Modesto; Salas, Margarita, E-mail: msalas@cbm.csic.es

    2014-11-15

    Protein-primed replication constitutes a generalized mechanism to initiate DNA or RNA synthesis in linear genomes, including viruses, gram-positive bacteria, linear plasmids and mobile elements. By this mechanism a specific amino acid primes replication and becomes covalently linked to the genome ends. Despite the fact that TPs lack sequence homology, they share a similar structural arrangement, with the priming residue in the C-terminal half of the protein and an accumulation of positively charged residues at the N-terminal end. In addition, various bacteriophage TPs have been shown to have DNA-binding capacity that targets TPs and their attached genomes to the host nucleoid. Furthermore, a number of bacteriophage TPs from different viral families and with diverse hosts also contain putative nuclear localization signals and localize in the eukaryotic nucleus, which could lead to the transport of the attached DNA. This suggests a possible role of bacteriophage TPs in prokaryote-to-eukaryote horizontal gene transfer. - Highlights: • Protein-primed genome replication constitutes a strategy to initiate DNA or RNA synthesis in linear genomes. • Bacteriophage terminal proteins (TPs) are covalently attached to viral genomes by their primary function priming DNA replication. • TPs are also DNA-binding proteins and target phage genomes to the host nucleoid. • TPs can also localize in the eukaryotic nucleus and may have a role in phage-mediated interkingdom gene transfer.

  5. Effect of gamma irradiation on bacteriophages used as viral indicators.

    Science.gov (United States)

    Jebri, Sihem; Hmaied, Fatma; Jofre, Juan; MariemYahya; Mendez, Javier; Barkallah, Insaf; Hamdi, Moktar

    2013-07-01

    This study aimed to examine the susceptibility of indicator bacteriophages towards γ-radiation to evaluate their appropriateness as viral indicators for water quality control. The effects of γ-radiation on naturally occurring somatic coliphages, F-specific coliphages and Escherichia coli were examined in raw sewage and sewage sludge. As well, the effects of radiation on bacteriophages ΦX174 and MS2, and E. coli all grown in the laboratory and seeded in distilled water, autoclaved raw sewage and a 1% peptone solution were evaluated. The inactivation of E. coli was fairly similar in all matrices. In contrast, inactivation of bacteriophages was significantly greater in distilled water than in the other matrices. These results showed the great influence of the matrix characteristics on virus inactivation. Somatic coliphages in raw sewage and sewage sludge and ΦX174 in autoclaved sewage were inactivated similarly and were far more resistant than F-specific coliphages, MS2 and E. coli. As well, F-specific RNA bacteriophages in raw sewage and sewage sludge and MS2 in autoclaved sewage were inactivated similarly and were more resistant than E. coli. In contrast, MS2 was more susceptible to γ-radiation than E. coli in distilled water. Our results showed that ΦX174 is a suitable indicator for estimating virus inactivation by γ-irradiation and corroborate the use of somatic coliphages to survey the viral quality of treated water and sludges.

  6. Multiple roles of genome-attached bacteriophage terminal proteins

    International Nuclear Information System (INIS)

    Protein-primed replication constitutes a generalized mechanism to initiate DNA or RNA synthesis in linear genomes, including viruses, gram-positive bacteria, linear plasmids and mobile elements. By this mechanism a specific amino acid primes replication and becomes covalently linked to the genome ends. Despite the fact that TPs lack sequence homology, they share a similar structural arrangement, with the priming residue in the C-terminal half of the protein and an accumulation of positively charged residues at the N-terminal end. In addition, various bacteriophage TPs have been shown to have DNA-binding capacity that targets TPs and their attached genomes to the host nucleoid. Furthermore, a number of bacteriophage TPs from different viral families and with diverse hosts also contain putative nuclear localization signals and localize in the eukaryotic nucleus, which could lead to the transport of the attached DNA. This suggests a possible role of bacteriophage TPs in prokaryote-to-eukaryote horizontal gene transfer. - Highlights: • Protein-primed genome replication constitutes a strategy to initiate DNA or RNA synthesis in linear genomes. • Bacteriophage terminal proteins (TPs) are covalently attached to viral genomes by their primary function priming DNA replication. • TPs are also DNA-binding proteins and target phage genomes to the host nucleoid. • TPs can also localize in the eukaryotic nucleus and may have a role in phage-mediated interkingdom gene transfer

  7. Innate and adaptive immunity in bacteria: mechanisms of programmed genetic variation to fight bacteriophages.

    Science.gov (United States)

    Bikard, David; Marraffini, Luciano A

    2012-02-01

    Bacteria are constantly challenged by bacteriophages (viruses that infect bacteria), the most abundant microorganism on earth. Bacteria have evolved a variety of immunity mechanisms to resist bacteriophage infection. In response, bacteriophages can evolve counter-resistance mechanisms and launch a 'virus versus host' evolutionary arms race. In this context, rapid evolution is fundamental for the survival of the bacterial cell. Programmed genetic variation mechanisms at loci involved in immunity against bacteriophages generate diversity at a much faster rate than random point mutation and enable bacteria to quickly adapt and repel infection. Diversity-generating retroelements (DGRs) and phase variation mechanisms enhance the generic (innate) immune response against bacteriophages. On the other hand, the integration of small bacteriophage sequences in CRISPR loci provide bacteria with a virus-specific and sequence-specific adaptive immune response. Therefore, although using different molecular mechanisms, both prokaryotes and higher organisms rely on programmed genetic variation to increase genetic diversity and fight rapidly evolving infectious agents.

  8. Novel Bacteroides host strains for detection of human- and animal-specific bacteriophages in water.

    Science.gov (United States)

    Wicki, Melanie; Auckenthaler, Adrian; Felleisen, Richard; Tanner, Marcel; Baumgartner, Andreas

    2011-03-01

    Bacteriophages active against specific Bacteroides host strains were shown to be suitable for detection of human faecal pollution. However, the practical application of this finding is limited because some specific host strains were restricted to certain geographic regions. In this study, novel Bacteroides host strains were isolated that discriminate human and animal faecal pollution in Switzerland. Two strains specific for bacteriophages present in human faecal contamination and three strains specific for bacteriophages indicating animal faecal contamination were evaluated. Bacteriophages infecting human strains were exclusively found in human wastewater, whereas animal strains detected bacteriophages only in animal waste. The newly isolated host strains could be used to determine the source of surface and spring water faecal contamination in field situations. Applying the newly isolated host Bacteroides thetaiotaomicron ARABA 84 for detection of bacteriophages allowed the detection of human faecal contamination in spring water.

  9. Simultaneous loss of bacteriophage receptor and coaggregation mediator activities in Actinomyces viscosus MG-1.

    OpenAIRE

    Tylenda, C A; Enriquez, E.; Kolenbrander, P. E.; Delisle, A L

    1985-01-01

    Actinomyces bacteriophages were used as tools to study coaggregation between actinomyces and streptococci. Four bacteriophage isolates, phages AV-1, AV-2, AV-3, and 1281, bound to coaggregation group A Actinomyces viscosus and to group E A. naeslundii. No binding to groups B, C, D, or F was observed. Only A. viscosus MG-1 was capable of supporting a productive infection by these phages. Spontaneously occurring bacteriophage-resistant mutants of A. viscosus MG-1 were isolated and were shown to...

  10. Template reporter bacteriophage platform and multiple bacterial detection assays based thereon

    Science.gov (United States)

    Goodridge, Lawrence (Inventor)

    2007-01-01

    The invention is a method for the development of assays for the simultaneous detection of multiple bacteria. A bacteria of interest is selected. A host bacteria containing plasmid DNA from a T even bacteriophage that infects the bacteria of interest is infected with T4 reporter bacteriophage. After infection, the progeny bacteriophage are plating onto the bacteria of interest. The invention also includes single-tube, fast and sensitive assays which utilize the novel method.

  11. Natural products from the ascidian Botrylloides giganteum, from the sponges Verongula gigantea, Ircinia felix, Cliona delitrix and from the nudibranch Tambja eliora, from the Brazilian coastline

    International Nuclear Information System (INIS)

    Two new marine metabolites, 3Z, 6Z, 9Z-dodecatrien-1-ol (1) from the ascidian Botrylloides giganteum and 4H-pyran-2ol acetate from the sponge Ircinia felix (4) are herein reported. The known bromotyrosine compounds, 2-(3,5-dibromo-4-methoxyphenyl)-N,N,Ndimethylethanammonium (2) and 2,6-dibromo-4-(2-(trimethylammonium)ethyl)phenol (3), have been isolated from the sponge Verongula gigantea. Serotonin (5) is reported for the first time from the sponge Cliona delitrix, and tambjamines A (15) and D (16) isolated as their respective salts from the nudibranch Tambja eliora. Only tambjamine D presented cytotoxicity against CEM (IC5)0 12.2 μg/mL) and HL60 (IC50 13.2 μg/mL) human leukemia cells, MCF-7 breast cancer cells (IC50 13.2 μg/mL), colon HCT-8 cancer cells (IC50 10.1 μg/mL) and murine melanoma B16 cancer cells (IC50 6.7 μg/mL). (author)

  12. Albany/FELIX: a parallel, scalable and robust, finite element, first-order Stokes approximation ice sheet solver built for advanced analysis

    Directory of Open Access Journals (Sweden)

    I. Kalashnikova

    2014-11-01

    Full Text Available This paper describes a new parallel, scalable and robust finite-element based solver for the first-order Stokes momentum balance equations for ice flow. The solver, known as Albany/FELIX, is constructed using the component-based approach to building application codes, in which mature, modular libraries developed as a part of the Trilinos project are combined using abstract interfaces and Template-Based Generic Programming, resulting in a final code with access to dozens of algorithmic and advanced analysis capabilities. Following an overview of the relevant partial differential equations and boundary conditions, the numerical methods chosen to discretize the ice flow equations are described, along with their implementation. The results of several verification studies of the model accuracy are presented using: (1 new test cases derived using the method of manufactured solutions, and (2 canonical ice sheet modeling benchmarks. Model accuracy and convergence with respect to mesh resolution is then studied on problems involving a realistic Greenland ice sheet geometry discretized using structured and unstructured meshes. Also explored as a part of this study is the effect of vertical mesh resolution on the solution accuracy and solver performance. The robustness and scalability of our solver on these problems is demonstrated. Lastly, we show that good scalability can be achieved by preconditioning the iterative linear solver using a new algebraic multilevel preconditioner, constructed based on the idea of semi-coarsening.

  13. The effect of bacteriophages T4 and HAP1 on in vitro melanoma migration

    Directory of Open Access Journals (Sweden)

    Boratyński Janusz

    2009-01-01

    Full Text Available Abstract Background The antibacterial activity of bacteriophages has been described rather well. However, knowledge about the direct interactions of bacteriophages with mammalian organisms and their other, i.e. non-antibacterial, activities in mammalian systems is quite scarce. It must be emphasised that bacteriophages are natural parasites of bacteria, which in turn are parasites or symbionts of mammals (including humans. Bacteriophages are constantly present in mammalian bodies and the environment in great amounts. On the other hand, the perspective of the possible use of bacteriophage preparations for antibacterial therapies in cancer patients generates a substantial need to investigate the effects of phages on cancer processes. Results In these studies the migration of human and mouse melanoma on fibronectin was inhibited by purified T4 and HAP1 bacteriophage preparations. The migration of human melanoma was also inhibited by the HAP1 phage preparation on matrigel. No response of either melanoma cell line to lipopolysaccharide was observed. Therefore the effect of the phage preparations cannot be attributed to lipopolysaccharide. No differences in the effects of T4 and HAP1 on melanoma migration were observed. Conclusion We believe that these observations are of importance for any further attempts to use bacteriophage preparations in antibacterial treatment. The risk of antibiotic-resistant hospital infections strongly affects cancer patients and these results suggest the possibility of beneficial phage treatment. We also believe that they will contribute to the general understanding of bacteriophage biology, as bacteriophages, extremely ubiquitous entities, are in permanent contact with human organisms.

  14. Methods for generation of reporter phages and immobilization of active bacteriophages on a polymer surface

    Science.gov (United States)

    Applegate, Bruce Michael (Inventor); Perry, Lynda Louise (Inventor); Morgan, Mark Thomas (Inventor); Kothapalli, Aparna (Inventor)

    2012-01-01

    Novel reporter bacteriophages are provided. Provided are compositions and methods that allow bacteriophages that are used for specific detection or killing of E. coli 0157:H7 to be propagated in nonpathogenic E. coli, thereby eliminating the safety and security risks of propagation in E. coli 0157:H7. Provided are compositions and methods for attaching active bacteriophages to the surface of a polymer in order to kill target bacteria with which the phage comes into contact. Provided are modified bacteriophages immobilized to a surface, which capture E. coli 0157:H7 and cause the captured cells to emit light or fluorescence, allowing detection of the bacteria in a sample.

  15. STUDIES ON THE BACTERIOPHAGE OF D'HERELLE : IV. CONCERNING THE ONENESS OF THE BACTERIOPHAGE.

    Science.gov (United States)

    Bronfenbrenner, J J; Korb, C

    1925-11-30

    Lytic filtrates, active against Bacillus dysenterioe Shiga, Bacillus coli, Bacillus pestis cavioe, and staphylococcus respectively, proved to be differently affected by changes in hydrogen ion concentration. Anti-staphylococcus lysin was the least resistant of the four, showing deterioration in 3 hours at 7 degrees C. beyond the zone of hydrogen ion concentration limited by C(H) = 6.3 x 10(-5) and C(H) = 1.6 x 10(-9). Under the same conditions, the zone of resistance of anti-coli filtrate lay between C(H) = 2.7 x 10(-3) and C(H) = 2.5 x 10(-11), and that of anti-Shiga between C(H) = 1-7 x 10(-4) and C(H) = 1-3 x 10(-11). Anti-pestis cavioe filtrate was most resistant of the four, retaining its full activity in the zone from C(H) = 1 x 10(-3) to C(H) = 3.5 x 10(-12). The fact that these differences in individual resistance persisted, notwithstanding the repeated passage of lytic filtrates through cultures of bacteria other than those against which they were primarily active, seems to offer evidence in favor of a multiplicity of bacteriophages.

  16. Insights into Bacteriophage Application in Controlling Vibrio Species.

    Science.gov (United States)

    Letchumanan, Vengadesh; Chan, Kok-Gan; Pusparajah, Priyia; Saokaew, Surasak; Duangjai, Acharaporn; Goh, Bey-Hing; Ab Mutalib, Nurul-Syakima; Lee, Learn-Han

    2016-01-01

    Bacterial infections from various organisms including Vibrio sp. pose a serious hazard to humans in many forms from clinical infection to affecting the yield of agriculture and aquaculture via infection of livestock. Vibrio sp. is one of the main foodborne pathogens causing human infection and is also a common cause of losses in the aquaculture industry. Prophylactic and therapeutic usage of antibiotics has become the mainstay of managing this problem, however, this in turn led to the emergence of multidrug resistant strains of bacteria in the environment; which has raised awareness of the critical need for alternative non-antibiotic based methods of preventing and treating bacterial infections. Bacteriophages - viruses that infect and result in the death of bacteria - are currently of great interest as a highly viable alternative to antibiotics. This article provides an insight into bacteriophage application in controlling Vibrio species as well underlining the advantages and drawbacks of phage therapy. PMID:27486446

  17. Bacteriophages as Weapons Against Bacterial Biofilms in the Food Industry.

    Science.gov (United States)

    Gutiérrez, Diana; Rodríguez-Rubio, Lorena; Martínez, Beatriz; Rodríguez, Ana; García, Pilar

    2016-01-01

    Microbiological contamination in the food industry is often attributed to the presence of biofilms in processing plants. Bacterial biofilms are complex communities of bacteria attached to a surface and surrounded by an extracellular polymeric material. Their extreme resistance to cleaning and disinfecting processes is related to a unique organization, which implies a differential bacterial growth and gene expression inside the biofilm. The impact of biofilms on health, and the economic consequences, has promoted the development of different approaches to control or remove biofilm formation. Recently, successful results in phage therapy have boosted new research in bacteriophages and phage lytic proteins for biofilm eradication. In this regard, this review examines the environmental factors that determine biofilm development in food-processing equipment. In addition, future perspectives for the use of bacteriophage-derived tools as disinfectants are discussed. PMID:27375566

  18. Bacteriophages as Weapons Against Bacterial Biofilms in the Food Industry.

    Science.gov (United States)

    Gutiérrez, Diana; Rodríguez-Rubio, Lorena; Martínez, Beatriz; Rodríguez, Ana; García, Pilar

    2016-01-01

    Microbiological contamination in the food industry is often attributed to the presence of biofilms in processing plants. Bacterial biofilms are complex communities of bacteria attached to a surface and surrounded by an extracellular polymeric material. Their extreme resistance to cleaning and disinfecting processes is related to a unique organization, which implies a differential bacterial growth and gene expression inside the biofilm. The impact of biofilms on health, and the economic consequences, has promoted the development of different approaches to control or remove biofilm formation. Recently, successful results in phage therapy have boosted new research in bacteriophages and phage lytic proteins for biofilm eradication. In this regard, this review examines the environmental factors that determine biofilm development in food-processing equipment. In addition, future perspectives for the use of bacteriophage-derived tools as disinfectants are discussed.

  19. Characterization of newly isolated lytic bacteriophages active against Acinetobacter baumannii.

    Directory of Open Access Journals (Sweden)

    Maia Merabishvili

    Full Text Available Based on genotyping and host range, two newly isolated lytic bacteriophages, myovirus vB_AbaM_Acibel004 and podovirus vB_AbaP_Acibel007, active against Acinetobacter baumannii clinical strains, were selected from a new phage library for further characterization. The complete genomes of the two phages were analyzed. Both phages are characterized by broad host range and essential features of potential therapeutic phages, such as short latent period (27 and 21 min, respectively, high burst size (125 and 145, respectively, stability of activity in liquid culture and low frequency of occurrence of phage-resistant mutant bacterial cells. Genomic analysis showed that while Acibel004 represents a novel bacteriophage with resemblance to some unclassified Pseudomonas aeruginosa phages, Acibel007 belongs to the well-characterized genus of the Phikmvlikevirus. The newly isolated phages can serve as potential candidates for phage cocktails to control A. baumannii infections.

  20. Bacteriophages and their implications on future biotechnology: a review

    Directory of Open Access Journals (Sweden)

    Haq Irshad

    2012-01-01

    Full Text Available Abstract Recently it has been recognized that bacteriophages, the natural predators of bacteria can be used efficiently in modern biotechnology. They have been proposed as alternatives to antibiotics for many antibiotic resistant bacterial strains. Phages can be used as biocontrol agents in agriculture and petroleum industry. Moreover phages are used as vehicles for vaccines both DNA and protein, for the detection of pathogenic bacterial strain, as display system for many proteins and antibodies. Bacteriophages are diverse group of viruses which are easily manipulated and therefore they have potential uses in biotechnology, research, and therapeutics. The aim of this review article is to enable the wide range of researchers, scientists, and biotechnologist who are putting phages into practice, to accelerate the progress and development in the field of biotechnology.

  1. Effect of HZE particles and space hadrons on bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Iurov, S.S.; Akoev, I.G.; Leonteva, G.A.

    1983-01-01

    The effects of particle radiation of the type encountered in space flight on bacteriophages are investigated. Survival and mutagenesis were followed in dry film cultures or liquid suspensions of T4Br(+) bacteriophage exposed to high-energy (HZE) particles during orbital flight, to alpha particles and accelerator-generated hardrons in the laboratory, and to high-energy cosmic rays at mountain altitudes. The HZE particles and high-energy hadrons are found to have a greater relative biological efficiency than standard gamma radiation, while exhibiting a highly inhomogeneous spatial structure in the observed biological and genetic effects. In addition, the genetic lesions observed are specific to the type of radiation exposure, consisting primarily of deletions and multiple lesions of low revertability, with mode of action depending on the linear energy transfer. 18 references.

  2. Effect of HZE particles and space hadrons on bacteriophages

    Science.gov (United States)

    Yurov, S. S.; Akoev, I. G.; Leont'eva, G. A.

    The effect of high energy (HZE) particles and high energy hadrons on T4Br+ bacteriophage was analyzed. The experiments were done in orbital flight, on high mountains, on an accelerator, and with an alpha particle source. We studied the survival rate of the bacteriophage, the mutation frequency, the mutation spectrum and the revertability under the action of chemical mutagens with a known mechanism of action on DNA. It was found that the biological efficiency of HZE particles and high energy hadrons is greater than that of γ radiation. The spectra of mutations produced by these mutations and the mechanisms of their action are also different. These effects were local, because of the mode of interaction of the radiant energy with biological objects, and depended on the linear energy transfer (LET). The modes have now been experimentally defined.

  3. BACTERIOPHAGE ENDOLYSINS AND THEIR USE IN BIOTECHNOLOGICAL PROCESSES

    Directory of Open Access Journals (Sweden)

    Lenka Tišáková

    2014-02-01

    Full Text Available Bacteriophage endolysins are peptidoglycan hydrolases, produced in the lytic system of bacteriophage in order to lyse host peptidoglycan from within and release virions into the environment. Phages infecting Gram-positive bacteria express endolysin genes with the characteristic modular structure, consisting of at least two functional domains: N-terminal enzymatically active domain (EAD and C-terminal cell wall binding domain (CBD. CBDs specifically recognize ligands and bind to the bacterial cell wall, whereas EAD catalyze lysis of the peptidoglycan bonds. The reveal of endolysin modular structure leads to new opportunities for domain swapping, construction of chimeras and production of specifically engineered recombinant endolysins and their functional domains with the diverse biotechnological applications from without, such as in detection, elimination and biocontrol of pathogens, or as anti-bacterials in experimental therapy.

  4. Bacteriophage exclusion, a new defense system

    Science.gov (United States)

    Barrangou, Rodolphe; van der Oost, John

    2015-01-01

    The ability to withstand viral predation is critical for survival of most microbes. Accordingly, a plethora of phage resistance systems has been identified in bacterial genomes (Labrie et al, 2010), including restriction-modification systems (R-M) (Tock & Dryden, 2005), abortive infection (Abi) (Chopin et al, 2005), Argonaute-based interference (Swarts et al, 2014), as well as clustered regularly interspaced short palindromic repeats (CRISPR) and associated protein (Cas) adaptive immune system (CRISPR-Cas) (Barrangou & Marraffini, 2014; Van der Oost et al, 2014). Predictably, the dark matter of bacterial genomes contains a wealth of genetic gold. A study published in this issue of The EMBO Journal by Goldfarb et al (2015) unveils bacteriophage exclusion (BREX) as a novel, widespread bacteriophage resistance system that provides innate immunity against virulent and temperate phage in bacteria. PMID:25502457

  5. The nucleotide sequence of the bacteriophage T5 ltf gene.

    Science.gov (United States)

    Kaliman, A V; Kulshin, V E; Shlyapnikov, M G; Ksenzenko, V N; Kryukov, V M

    1995-06-01

    The nucleotide sequence of the bacteriophage T5 Bg/II-BamHI fragment (4,835 bp in length) known to carry a gene encoding the LTF protein which forms the phage L-shaped tail fibers was determined. It was shown to contain an open reading frame for 1,396 amino acid residues that corresponds to a protein of 147.8 kDa. The coding region of ltf gene is preceded by a typical Shine-Dalgarno sequence. Downstream from the ltf gene there is a strong transcription terminator. Data bank analysis of the LTF protein sequence reveals 55.1% identity to the hypothetical protein ORF 401 of bacteriophage lambda in a segment of 118 amino acids overlap. PMID:7789514

  6. A method for the detection of bacteriophages from ocean water

    Science.gov (United States)

    Moebus, K.

    1980-03-01

    A method for the isolation of bacteriophages from ocean water is described. It precludes sample storage before starting phage-enrichment cultures and provides for the use of 3 sub-samples enriched with organic nutrients after 1, 2 and 3 days of incubation. The method was used with samples collected from 6 m below the surface at 48 stations between the European continental shelf and the Sargasso Sea. With 213 among 931 bacterial isolates about 250 strains of bacteriophages were detected by two methods of different sensitivity. From 14 samples taken east of the Azores 115 host bacteria have been found versus only 98 from 34 samples collected at westerly stations. The employment of more than one sub-sample per station as well as the use of more sensitive phage-detection procedures was found to be more advantageous the lower the concentration of cultivatable bacteria in a sample.

  7. Insights into bacteriophage application in controlling Vibrio species

    Directory of Open Access Journals (Sweden)

    Vengadesh Letchumanan

    2016-07-01

    Full Text Available Bacterial infections from various organisms including Vibrio sp. pose a serious hazard to humans in many forms from clinical infection to affecting the yield of agriculture and aquaculture via infection of livestock. Vibrio sp. is one of the main foodborne pathogens causing human infection and is also a common cause of losses in the aquaculture industry. Prophylactic and therapeutic usage of antibiotics has become the mainstay of managing this problem, however this in turn led to the emergence of multidrug resistant strains of bacteria in the environment; which has raised awareness of the critical need for alternative non antibiotic based methods of preventing and treating bacterial infections. Bacteriophages - viruses that infect and result in the death of bacteria – are currently of great interest as a highly viable alternative to antibiotics. This article provides an insight into bacteriophage application in controlling Vibrio species as well underlining the advantages and drawbacks of phage therapy.

  8. Characterization of newly isolated lytic bacteriophages active against Acinetobacter baumannii.

    Science.gov (United States)

    Merabishvili, Maia; Vandenheuvel, Dieter; Kropinski, Andrew M; Mast, Jan; De Vos, Daniel; Verbeken, Gilbert; Noben, Jean-Paul; Lavigne, Rob; Vaneechoutte, Mario; Pirnay, Jean-Paul

    2014-01-01

    Based on genotyping and host range, two newly isolated lytic bacteriophages, myovirus vB_AbaM_Acibel004 and podovirus vB_AbaP_Acibel007, active against Acinetobacter baumannii clinical strains, were selected from a new phage library for further characterization. The complete genomes of the two phages were analyzed. Both phages are characterized by broad host range and essential features of potential therapeutic phages, such as short latent period (27 and 21 min, respectively), high burst size (125 and 145, respectively), stability of activity in liquid culture and low frequency of occurrence of phage-resistant mutant bacterial cells. Genomic analysis showed that while Acibel004 represents a novel bacteriophage with resemblance to some unclassified Pseudomonas aeruginosa phages, Acibel007 belongs to the well-characterized genus of the Phikmvlikevirus. The newly isolated phages can serve as potential candidates for phage cocktails to control A. baumannii infections.

  9. Sequence and comparative analysis of Leuconostoc dairy bacteriophages.

    Science.gov (United States)

    Kot, Witold; Hansen, Lars H; Neve, Horst; Hammer, Karin; Jacobsen, Susanne; Pedersen, Per D; Sørensen, Søren J; Heller, Knut J; Vogensen, Finn K

    2014-04-17

    Bacteriophages attacking Leuconostoc species may significantly influence the quality of the final product. There is however limited knowledge of this group of phages in the literature. We have determined the complete genome sequences of nine Leuconostoc bacteriophages virulent to either Leuconostoc mesenteroides or Leuconostoc pseudomesenteroides strains. The phages have dsDNA genomes with sizes ranging from 25.7 to 28.4 kb. Comparative genomics analysis helped classify the 9 phages into two classes, which correlates with the host species. High percentage of similarity within the classes on both nucleotide and protein levels was observed. Genome comparison also revealed very high conservation of the overall genomic organization between the classes. The genes were organized in functional modules responsible for replication, packaging, head and tail morphogenesis, cell lysis and regulation and modification, respectively. No lysogeny modules were detected. To our knowledge this report provides the first comparative genomic work done on Leuconostoc dairy phages.

  10. Insights into Bacteriophage Application in Controlling Vibrio Species

    Science.gov (United States)

    Letchumanan, Vengadesh; Chan, Kok-Gan; Pusparajah, Priyia; Saokaew, Surasak; Duangjai, Acharaporn; Goh, Bey-Hing; Ab Mutalib, Nurul-Syakima; Lee, Learn-Han

    2016-01-01

    Bacterial infections from various organisms including Vibrio sp. pose a serious hazard to humans in many forms from clinical infection to affecting the yield of agriculture and aquaculture via infection of livestock. Vibrio sp. is one of the main foodborne pathogens causing human infection and is also a common cause of losses in the aquaculture industry. Prophylactic and therapeutic usage of antibiotics has become the mainstay of managing this problem, however, this in turn led to the emergence of multidrug resistant strains of bacteria in the environment; which has raised awareness of the critical need for alternative non-antibiotic based methods of preventing and treating bacterial infections. Bacteriophages – viruses that infect and result in the death of bacteria – are currently of great interest as a highly viable alternative to antibiotics. This article provides an insight into bacteriophage application in controlling Vibrio species as well underlining the advantages and drawbacks of phage therapy. PMID:27486446

  11. Choline-containing bacteriophage receptors in Streptococcus pneumoniae.

    OpenAIRE

    Lopez, R. (Rafael); Garcia, E.; Garcia, P.; Ronda, C; Tomasz, A.

    1982-01-01

    Choline-containing teichoic acid seems to be essential for the adsorption of bacteriophage Dp-1 to pneumococci. This conclusion is based on the following observations: In contrast to pneumococci grown in choline-containing medium, cells grown in medium containing ethanolamine or other submethylated aminoalcohols instead of choline were found to be resistant to infection by Dp-1. Live choline-grown bacteria and heat- or UV-inactivated cells and purified cell walls prepared from these cells wer...

  12. Bacteriophages : an underestimated role in human and animal health ?

    OpenAIRE

    Marianne eDe Paepe; Marion eLeclerc; Tinsley, Colin R.; Marie-Agnès ePetit

    2014-01-01

    Metagenomic approaches applied to viruses have highlighted their prevalence in almost all microbial ecosystems investigated. In all ecosystems, notably those associated with humans or animals, the viral fraction is dominated by bacteriophages. Whether they contribute to dysbiosis, i.e. the departure from microbiota composition in symbiosis at equilibrium and entry into a state favoring human or animal disease is unknown at present. This review summarizes what has been learnt on phages associa...

  13. Isolation of Actinomyces bacteriophage from human dental plaque.

    OpenAIRE

    Tylenda, C A; Calvert, C.; Kolenbrander, P. E.; Tylenda, A

    1985-01-01

    Human dental plaque samples were screened for the presence of bacteriophage for Actinomyces viscosus and Streptococcus sanguis. None of the 336 samples yielded phage for S. sanguis, but 10 contained virulent actinomyces phage. A high host cell specificity was observed in that one phage isolate infected only A. viscosus T14V, eight phage isolates infected only A. viscosus MG-1, and one infected both strains. None was capable of productively infecting various other actinomyces strains that repr...

  14. Genetic analysis of bacteriophages from clinical and environmental samples

    OpenAIRE

    Knapik, Kamila Z.

    2013-01-01

    Bacteriophages, viruses infecting bacteria, are uniformly present in any location where there are high numbers of bacteria, both in the external environment and the human body. Knowledge of their diversity is limited by the difficulty to culture the host species and by the lack of the universal marker gene present in all viruses. Metagenomics is a powerful tool that can be used to analyse viral communities in their natural environments. The aim of this study was to investigate diverse populat...

  15. Identification of mutations conferring 5-azacytidine resistance in bacteriophage

    OpenAIRE

    Arribas, María; Cabanillas, Laura; Lázaro, Ester

    2011-01-01

    RNA virus replication takes place at a very high error rate, and additional increases in this parameter can produce the extinction of virus infectivity. Nevertheless, RNA viruses can adapt to conditions of increased mutagenesis, which demonstrates that selection of beneficial mutations is also possible at higher-than-standard error rates. In this study we have analysed the evolutionary behaviour of bacteriophage Qβ populations when replication proceeds in the presence of the mutagenic nucleos...

  16. P. fluorescens biofilm control using bacteriophage ΦS1

    OpenAIRE

    Sillankorva, Sanna; Oliveira, Rosário; Vieira, M. J.; Sutherland, Ian W.; Azeredo, Joana

    2004-01-01

    Pseudomonas fluorescens biofilms contribute to the spoilage of dairy industry products due to the proteolytic activity of some Pseudomonas fluorescens strains. The eradication of these biofilms is difficult using the traditional chemical biocides due to the low removal action of these agents. Additionally chemical control leaves inactivated cells attached to the surface that tends to provide an ideal environment for further bacterial adhesion and growth. Bacteriophages can be seen as good alt...

  17. Ecology of Anti-Biofilm Agents I: Antibiotics versus Bacteriophages

    OpenAIRE

    Abedon, Stephen T.

    2015-01-01

    Bacteriophages, the viruses that infect bacteria, have for decades been successfully used to combat antibiotic-resistant, chronic bacterial infections, many of which are likely biofilm associated. Antibiotics as anti-biofilm agents can, by contrast, be inefficacious against even genetically sensitive targets. Such deficiencies in usefulness may result from antibiotics, as naturally occurring compounds, not serving their producers, in nature, as stand-alone disruptors of mature biofilms. Anti-...

  18. Bacteriophages infecting Bacteroides as a marker for microbial source tracking.

    Science.gov (United States)

    Jofre, Joan; Blanch, Anicet R; Lucena, Francisco; Muniesa, Maite

    2014-05-15

    Bacteriophages infecting certain strains of Bacteroides are amid the numerous procedures proposed for tracking the source of faecal pollution. These bacteriophages fulfil reasonably well most of the requirements identified as appropriate for a suitable marker of faecal sources. Thus, different host strains are available that detect bacteriophages preferably in water contaminated with faecal wastes corresponding to different animal species. For phages found preferably in human faecal wastes, which are the ones that have been more extensively studied, the amounts of phages found in waters contaminated with human fecal samples is reasonably high; these amounts are invariable through the time; their resistance to natural and anthropogenic stressors is comparable to that of other relatively resistant indicator of faecal pollution such us coliphages; the abundance ratios of somatic coliphages and bacteriophages infecting Bacteroides thetaiotaomicron GA17 are unvarying in recent and aged contamination; and standardised detection methods exist. These methods are easy, cost effective and provide data susceptible of numerical analysis. In contrast, there are some uncertainties regarding their geographical stability, and consequently suitable hosts need to be isolated for different geographical areas. However, a feasible method has been described to isolate suitable hosts in a given geographical area. In summary, phages infecting Bacteroides are a marker of faecal sources that in our opinion merits being included in the "toolbox" for microbial source tracking. However, further research is still needed in order to make clear some uncertainties regarding some of their characteristics and behaviour, to compare their suitability to the one of emerging methods such us targeting Bacteroidetes by qPCR assays; or settling molecular methods for their determination.

  19. Label-free Gram-negative bacteria detection using bacteriophage-adhesin-coated long-period gratings.

    Science.gov (United States)

    Brzozowska, Ewa; Koba, Marcin; Śmietana, Mateusz; Górska, Sabina; Janik, Monika; Gamian, Andrzej; Bock, Wojtek J

    2016-03-01

    This paper presents a novel application of a highly sensitive sensor based on long-period gratings (LPGs) coated with T4 bacteriophage adhesin for Gram-negative bacteria detection. We show here, that the sensor evidently recognizes Escherichia coli K-12 (PCM2560), whereas in the reference tests - ELISA and BIAcore - the results are questionable. For LPGs sensor the resonant wavelength shift observed for E. coli K-12 was approximately half of that measured for E.coli B (positive control). The BIAcore readings (RU) for E. coli K-12 were at 10% level of the signal obtained for E .coli B. These results confirm the improved sensitivity of the LPGs sensor. Moreover, we also show that application of adhesin may allow for efficient detection of E. coli O111 (PCM418), Klebsiella pneumoniae O1 (PCM1) and Yersinia enterocolitica O1 (PCM1879). The specificity of binding bacteria by the adhesin is discussed and it is determined by a distinct region of lipopolysaccharide receptors and/or by the presence of outer-membrane protein C in an outer membrane of Gram-negative bacteria.

  20. Isolation of Lactic Acid Bacteria Bacteriophages from Dairy Products

    Directory of Open Access Journals (Sweden)

    Elnaz Shokrani

    2013-09-01

    Full Text Available Backgrounds: Lactococcus lactis (L. lactis is one of the most important microorganisms used in dairy industry for production of fermented milk products. Bacteriophages which attack  L. lactis are a serious threat to the dairy industry because of their negative effects on fermentation processes. Methods: Samples of raw milk were examined for the presence of lactococcal bacteriophages. Samples were centrifuged and then filtered through 0.45µm pore size filters. The filtrates were added to early-exponential cultures of Lactococcus lactis subspp. Lactis (PTCC 1336. Overlay method was used to detect the formation of plaques. After isolation and concentration of phages, serial dilutions of phage stock were used to determine titer of phage in concentrated sample. Electron Microscopy was used for observation and characterization of structural details of bacteriophages. Results: Two phages were isolated; one of them had a hexagonal head of 45×30 nm in diameter and a flexible non-contractile tail of 70nm long which belonged to Siphoviridae. The other had a short tail and a hexagonal head of 53×60 nm in diameter which was a member of Podoviridae family. Conclusion: In this study, for the first time, two phages were isolated from milk. This does not reduce the significance of phage control in different stages of the production. The spread of the phages in the production plant can be very harmful.

  1. Temperate bacteriophages collected by outer membrane vesicles in Komagataeibacter intermedius.

    Science.gov (United States)

    Kharina, Alla; Podolich, Olga; Faidiuk, Iuliia; Zaika, Sergiy; Haidak, Andriy; Kukharenko, Olga; Zaets, Iryna; Tovkach, Fedor; Reva, Oleg; Kremenskoy, Maxim; Kozyrovska, Natalia

    2015-04-01

    The acetic acid bacteria have mainly relevance for bacterial cellulose production and fermented bio-products manufacture. The purpose of this study was to identify temperate bacteriophages in a cellulose-producing bacterial strain Komagataeibacter intermedius IMBG180. Prophages from K. intermedius IMBG180 were induced with mitomycin C and nalidixic acid. Transmission electron microscopy analysis exhibited tailed bacteriophages belonging to Myoviridae. A PCR assay targeting the capsid gene of the myoviruses proved phylogenetic position of induced phages. Nalidixic acid was poor inducer of prophages, however, it induced the OMV-like particles release. Size of OMVs depended on an antibiotic applied for phage induction and varied in the range of 30-80 and 120-200 nm. Inside some of them, tails of phages have been visible. Under conditions, inducing prophages, OMVs acted as the collectors of formed phage particles, using outer membrane receptors for phage detection (in this case, outer membrane siderophore receptor), and fulfilled therefore "a cleaning," as well as defensive functions, preventing bacteriophage spread outside population. This is the first description of myoviruses affiliated to K. intermedius, as well as outer membrane vesicles interaction with phages within this host.

  2. Bacteriophages and medical oncology: targeted gene therapy of cancer.

    Science.gov (United States)

    Bakhshinejad, Babak; Karimi, Marzieh; Sadeghizadeh, Majid

    2014-08-01

    Targeted gene therapy of cancer is of paramount importance in medical oncology. Bacteriophages, viruses that specifically infect bacterial cells, offer a variety of potential applications in biomedicine. Their genetic flexibility to go under a variety of surface modifications serves as a basis for phage display methodology. These surface manipulations allow bacteriophages to be exploited for targeted delivery of therapeutic genes. Moreover, the excellent safety profile of these viruses paves the way for their potential use as cancer gene therapy platforms. The merge of phage display and combinatorial technology has led to the emergence of phage libraries turning phage display into a high throughput technology. Random peptide libraries, as one of the most frequently used phage libraries, provide a rich source of clinically useful peptide ligands. Peptides are known as a promising category of pharmaceutical agents in medical oncology that present advantages such as inexpensive synthesis, efficient tissue penetration and the lack of immunogenicity. Phage peptide libraries can be screened, through biopanning, against various targets including cancer cells and tissues that results in obtaining cancer-homing ligands. Cancer-specific peptides isolated from phage libraries show huge promise to be utilized for targeting of various gene therapy vectors towards malignant cells. Beyond doubt, bacteriophages will play a more impressive role in the future of medical oncology.

  3. Bacteriophages and medical oncology: targeted gene therapy of cancer.

    Science.gov (United States)

    Bakhshinejad, Babak; Karimi, Marzieh; Sadeghizadeh, Majid

    2014-08-01

    Targeted gene therapy of cancer is of paramount importance in medical oncology. Bacteriophages, viruses that specifically infect bacterial cells, offer a variety of potential applications in biomedicine. Their genetic flexibility to go under a variety of surface modifications serves as a basis for phage display methodology. These surface manipulations allow bacteriophages to be exploited for targeted delivery of therapeutic genes. Moreover, the excellent safety profile of these viruses paves the way for their potential use as cancer gene therapy platforms. The merge of phage display and combinatorial technology has led to the emergence of phage libraries turning phage display into a high throughput technology. Random peptide libraries, as one of the most frequently used phage libraries, provide a rich source of clinically useful peptide ligands. Peptides are known as a promising category of pharmaceutical agents in medical oncology that present advantages such as inexpensive synthesis, efficient tissue penetration and the lack of immunogenicity. Phage peptide libraries can be screened, through biopanning, against various targets including cancer cells and tissues that results in obtaining cancer-homing ligands. Cancer-specific peptides isolated from phage libraries show huge promise to be utilized for targeting of various gene therapy vectors towards malignant cells. Beyond doubt, bacteriophages will play a more impressive role in the future of medical oncology. PMID:25012686

  4. MetaPhinder—Identifying Bacteriophage Sequences in Metagenomic Data Sets

    Science.gov (United States)

    Villarroel, Julia; Lund, Ole; Voldby Larsen, Mette; Nielsen, Morten

    2016-01-01

    Bacteriophages are the most abundant biological entity on the planet, but at the same time do not account for much of the genetic material isolated from most environments due to their small genome sizes. They also show great genetic diversity and mosaic genomes making it challenging to analyze and understand them. Here we present MetaPhinder, a method to identify assembled genomic fragments (i.e.contigs) of phage origin in metagenomic data sets. The method is based on a comparison to a database of whole genome bacteriophage sequences, integrating hits to multiple genomes to accomodate for the mosaic genome structure of many bacteriophages. The method is demonstrated to out-perform both BLAST methods based on single hits and methods based on k-mer comparisons. MetaPhinder is available as a web service at the Center for Genomic Epidemiology https://cge.cbs.dtu.dk/services/MetaPhinder/, while the source code can be downloaded from https://bitbucket.org/genomicepidemiology/metaphinder or https://github.com/vanessajurtz/MetaPhinder. PMID:27684958

  5. Alternatives to antibiotics: utilization of bacteriophage to treat colibacillosis and prevent foodborne pathogens.

    Science.gov (United States)

    Huff, W E; Huff, G R; Rath, N C; Balog, J M; Donoghue, A M

    2005-04-01

    Bacteriophages are viruses that infect and kill bacteria. Bacteriophage do not infect animal and plant cells, which makes them a potentially safe alternative to antibiotics. We have been conducting research on the efficacy of bacteriophage to prevent and treat colibacillosis in poultry. Bacteriophages that were lytic to a non-motile, serotype 02 isolate of Escherichia coli were isolated from municipal wastewater treatment plants and poultry processing plants. This E. coli isolate is pathogenic to poultry, causing severe respiratory and systemic infections. Two bacteriophage isolates were selected for use in studies designed to determine the efficacy of these bacteriophage to prevent and treat severe colibacillosis in poultry. Colibacillosis was induced by injecting 6 x 10(4) cfu of E. coli into the thoracic air sac when birds were 1 wk of age. Initial studies demonstrated that mortality was significantly reduced from 85 to 35% when the challenge culture was mixed with equal titers of bacteriophage, and the birds were completely protected when the challenge culture was mixed with 10 pfu of bacteriophage. In subsequent studies, we have shown that an aerosol spray of bacteriophage given to birds prior to this E. coli challenge could significantly reduce mortality even when given 3 d prior to the E. coli challenge. Our research on treating colibacillosis in poultry has demonstrated that an intramuscular injection of bacteriophage given 24 or 48 h after the birds were challenged rescued the birds from this severe E. coli infection. We have demonstrated that bacteriophage can be used to prevent and treat colibacillosis in poultry and may provide an effective alternative to antibiotic use in animal production. PMID:15844825

  6. Pasteurella haemolytica bacteriophage: identification, partial characterization, and relationship of temperate bacteriophages from isolates of Pasteurella haemolytica (biotype A, serotype 1)

    Energy Technology Data Exchange (ETDEWEB)

    Richards, A.B.; Renshaw, H.W.; Sneed, L.W.

    1985-05-01

    Pasteurella haemolytica (biotype A, serotype 1) isolates (n = 15) from the upper respiratory tract of clinically normal cattle, as well as from lung lesions from cases of fatal bovine pasteurellosis, were examined for the presence of bacteriophage after irradiation with UV light. Treatment of all P haemolytica isolates with UV irradiation resulted in lysis of bacteria due to the induction of vegetative development of bacteriophages. The extent of growth inhibition and bacterial lysis in irradiated cultures was UV dose-dependent. Bacterial cultures exposed to UV light for 20 s reached peak culture density between 60 and 70 minutes after irradiation; thereafter, culture density declined rapidly, so that by 120 minutes, it was approximately 60% of the original value. When examined ultrastructurally, lytic cultures from each isolate revealed bacteriophages with an overall length of approximately 200 nm and that appeared to have a head with icosahedral symmetry and a contractile tail. Cell-free filtrate from each noninduced bacterial isolate was inoculated onto the other bacterial isolates in a cross-culture sensitivity assay for the presence of phages lytic for the host bacterial isolates. Zones of lysis (plaques) did not develop when bacterial lawns grown from the different isolates were inoculated with filtrates from the heterologous isolates.

  7. Isolation and characterization of a lytic bacteriophage φKp-lyy15 of Klebsiella pneumoniae

    Institute of Scientific and Technical Information of China (English)

    Yinyin; Lu; Hongyan; Shi; Zhe; Zhang; Fang; Han; Jinghua; Li; Yanbo; Sun

    2015-01-01

    <正>Dear Editor,Bacteriophages(phages)are viruses that specifically infect and kill bacteria.They are ubiquitous throughout all environments that bacteria inhabit.Following their discovery by F.W.Twort in 1915 and F.d’Herele in 1917,bacteriophages were recognized as potential agents to treat bacterial diseases and phage therapy has been used

  8. Detection of bacteriophage-infected cells of Lactococcus lactis using flow cytometry

    DEFF Research Database (Denmark)

    Michelsen, Ole; Cuesta-Dominguez, Álvaro; Albrektsen, Bjarne;

    2007-01-01

    Bacteriophage infection in dairy fermentation constitutes a serious problem worldwide. We have studied bacteriophage infection in Lactococcus lactis by using the flow cytometer. The first effect of the infection of the bacterium is a change from cells in chains toward single cells. We interpret...

  9. Polymer-based delivery systems for support and delivery of bacteriophages

    Science.gov (United States)

    Brown, Alyssa Marie

    One of the most urgent problems in the fields of medicine and agriculture is the decreasing effectiveness of antibiotics. Once a miracle drug, antibiotics have recently become associated with the creation of antibiotic-resistant bacteria. The main limitations of these treatments include lack of both adaptability and specificity. To overcome these shortcomings of current antibiotic treatments, there has been a renewed interest in bacteriophage research. Bacteriophages are naturally-occurring viruses that lyse bacteria. They are highly specific, with each bacteriophage type lysing a narrow range of bacteria strains. Bacteriophages are also ubiquitous biological entities, populating environments where bacterial growth is supported. Just as humans are exposed to bacteria in their daily lives, we are exposed to bacteriophages as well. To use bacteriophages in practical applications, they must be delivered to the site of an infection in a controlled-release system. Two systems were studied to observe their support of bacteriophage lytic activity, as well as investigate the possibility of controlling bacteriophage release rates. First, hydrogels were studied, using crosslinking and blending techniques to achieve a range of release profiles. Second, polyanhydride microparticles were studied, evaluating release rates as a function of monomer chemistries.

  10. [The bacteriophages Yersinia pseudotuberculosis: the detection in strains of different O-serovars and their identification].

    Science.gov (United States)

    Makedonova, L D; Kudriakova, T A; Kachkina, G V; Gaevskaia, N E

    2013-08-01

    The sample included five indicator pseudotuberculosis strains. The application of these strains permitted to isolate out of 161 strains of Y. pseudotuberculosis 9 bacteriophages identical by their morphologic and serologic characteristics but having individual particularities in their lytic activity. The test on sensitivity to bacteriophages can be used in laboratory diagnostic to differentiate the strains of Yersinia pseudotuberculosis.

  11. Biocontrol of Escherichia coli O157:H7 using a bacteriophage cocktail in laboratory media

    Science.gov (United States)

    Bacteriophages are natural enemies of bacteria, and therefore, logical candidates to evaluate as antibacterial agents for the control of foodborne pathogens. The effect of a bacteriophage treatment on the prevention of E. coli O157:H7 growth was investigated in Tryptic Soy Broth (TSB) laboratory med...

  12. Complete Genome Sequence of a Myoviridae Bacteriophage Infecting Salmonella enterica Serovar Typhimurium.

    Science.gov (United States)

    Paradiso, Rubina; Orsini, Massimiliano; Bolletti Censi, Sergio; Borriello, Giorgia; Galiero, Giorgio

    2016-01-01

    The bacteriophage 118970_sal3 was isolated from water buffalo feces in southern Italy, exhibiting lytic activity against Salmonella enterica serovar Typhimurium. This bacteriophage belongs to the Myoviridae family and has a 39,464-bp double-stranded DNA (ds-DNA) genome containing 53 coding sequences (CDSs). PMID:27688333

  13. Complete Genome Sequence of a Lytic Siphoviridae Bacteriophage Infecting Several Serovars of Salmonella enterica.

    Science.gov (United States)

    Paradiso, Rubina; Lombardi, Serena; Iodice, Maria Grazia; Riccardi, Marita Georgia; Orsini, Massimiliano; Bolletti Censi, Sergio; Galiero, Giorgio; Borriello, Giorgia

    2016-01-01

    The bacteriophage 100268_sal2 was isolated from water buffalo feces in southern Italy, exhibiting lytic activity against several subspecies of Salmonella enterica This bacteriophage belongs to the Siphoviridae family and has a 125,114-bp double-stranded DNA (ds-DNA) genome containing 188 coding sequences (CDSs). PMID:27688334

  14. Complete Genome Sequence of a Myoviridae Bacteriophage Infecting Salmonella enterica Serovar Typhimurium

    Science.gov (United States)

    Paradiso, Rubina; Orsini, Massimiliano; Bolletti Censi, Sergio; Galiero, Giorgio

    2016-01-01

    The bacteriophage 118970_sal3 was isolated from water buffalo feces in southern Italy, exhibiting lytic activity against Salmonella enterica serovar Typhimurium. This bacteriophage belongs to the Myoviridae family and has a 39,464-bp double-stranded DNA (ds-DNA) genome containing 53 coding sequences (CDSs). PMID:27688333

  15. Complete Genome Sequence of a Lytic Siphoviridae Bacteriophage Infecting Several Serovars of Salmonella enterica

    Science.gov (United States)

    Paradiso, Rubina; Lombardi, Serena; Iodice, Maria Grazia; Riccardi, Marita Georgia; Orsini, Massimiliano; Bolletti Censi, Sergio; Galiero, Giorgio

    2016-01-01

    The bacteriophage 100268_sal2 was isolated from water buffalo feces in southern Italy, exhibiting lytic activity against several subspecies of Salmonella enterica. This bacteriophage belongs to the Siphoviridae family and has a 125,114-bp double-stranded DNA (ds-DNA) genome containing 188 coding sequences (CDSs). PMID:27688334

  16. Removal of MS2, Qβ and GA bacteriophages during drinking water treatment at pilot scale.

    Science.gov (United States)

    Boudaud, Nicolas; Machinal, Claire; David, Fabienne; Fréval-Le Bourdonnec, Armelle; Jossent, Jérôme; Bakanga, Fanny; Arnal, Charlotte; Jaffrezic, Marie Pierre; Oberti, Sandrine; Gantzer, Christophe

    2012-05-15

    The removal of MS2, Qβ and GA, F-specific RNA bacteriophages, potential surrogates for pathogenic waterborne viruses, was investigated during a conventional drinking water treatment at pilot scale by using river water, artificially and independently spiked with these bacteriophages. The objective of this work is to develop a standard system for assessing the effectiveness of drinking water plants with respect to the removal of MS2, Qβ and GA bacteriophages by a conventional pre-treatment process (coagulation-flocculation-settling-sand filtration) followed or not by an ultrafiltration (UF) membrane (complete treatment process). The specific performances of three UF membranes alone were assessed by using (i) pre-treated water and (ii) 0.1 mM sterile phosphate buffer solution (PBS), spiked with bacteriophages. These UF membranes tested in this work were designed for drinking water treatment market and were also selected for research purpose. The hypothesis serving as base for this study was that the interfacial properties for these three bacteriophages, in terms of electrostatic charge and the degree of hydrophobicity, could induce variations in the removal performances achieved by drinking water treatments. The comparison of the results showed a similar behaviour for both MS2 and Qβ surrogates whereas it was particularly atypical for the GA surrogate. The infectious character of MS2 and Qβ bacteriophages was mostly removed after clarification followed by sand filtration processes (more than a 4.8-log reduction) while genomic copies were removed at more than a 4.0-log after the complete treatment process. On the contrary, GA bacteriophage was only slightly removed by clarification followed by sand filtration, with less than 1.7-log and 1.2-log reduction, respectively. After the complete treatment process achieved, GA bacteriophage was removed with less than 2.2-log and 1.6-log reduction, respectively. The effectiveness of the three UF membranes tested in terms of

  17. Screening and identification of receptor antagonist for shiga toxin from random peptides displayed on filamentous bacteriophages

    Institute of Scientific and Technical Information of China (English)

    韩照中; 苏国富; 黄翠芬

    1999-01-01

    The bacteriophage clones which can bind with shiga toxin B subunit (StxB) and inhibit cytotoxicity of shiga toxin were obtained by using antibody capturing method from a 15-mer random peptide library displayed on the surface of bacteriophage fd. Among them, one peptide encoded by the random DNA region of a selected bacteriophage (A12) was synthesized and tested in vitro and in vivo, where the peptide competed with the receptor of shiga toxin to bind StxB, and inhibited the cytotoxicity and enterotoxicity of shiga toxin. The peptide can also block other apparently unrelated StxB binding bacteriophage (A3), which suggests that there are overlapping StxB interaction sites for those ligands with different sequences. The results provide a demonstration of bacteriophage display to screen peptide ligands for a small and/or unable biotinylated molecule by antibodies-capturing strategy, and take the lead for the development of receptor antagonists for shiga toxin.

  18. Adsorption of T4 bacteriophages on planar indium tin oxide surface via controlled surface tailoring.

    Science.gov (United States)

    Liana, Ayu Ekajayanthi; Chia, Ed Win; Marquis, Christopher P; Gunawan, Cindy; Gooding, J Justin; Amal, Rose

    2016-04-15

    The work investigates the influence of surface physicochemical properties of planar indium tin oxide (ITO) as a model substrate on T4 bacteriophage adsorption. A comparative T4 bacteriophage adsorption study shows a significant difference in bacteriophage adsorption observed on chemically modified planar ITO when compared to similarly modified particulate ITO, which infers that trends observed in virus-particle interaction studies are not necessarily transferrable to predict virus-planar surface adsorption behaviour. We also found that ITO surfaces modified with methyl groups, (resulting in increased surface roughness and hydrophobicity) remained capable of adsorbing T4 bacteriophage. The adsorption of T4 onto bare, amine and carboxylic functionalised planar ITO suggests the presence of a unique binding behaviour involving specific functional groups on planar ITO surface beyond the non-specific electrostatic interactions that dominate phage to particle interactions. The paper demonstrates the significance of physicochemical properties of surfaces on bacteriophage-surface interactions.

  19. Bacteriophages as anti-infective agents: recent developments and regulatory challenges.

    Science.gov (United States)

    Gilmore, Brendan F

    2012-05-01

    The biennial meeting on 'Exploiting Bacteriophages for Bioscience, Biotechnology and Medicine', held in London, UK, on 20 January 2012, and chaired by George Salmond (University of Cambridge, UK) hosted over 50 participants representing 13 countries. The highly multidisciplinary meeting covered a diverse range of topics, reflecting the current expansion of interest in this field, including the use of bacteriophages as the source of biochemical reagents for molecular biology, bacteriophages for the treatment of human and animal diseases, bacteriophage-based diagnostics and therapeutic delivery technologies and necessity for, and regulatory challenges associated with, robust clinical trials of phage-based therapeutics. This report focuses on a number of presentations from the meeting relating to cutting-edge research on bacteriophages as anti-infective agents.

  20. Rapid and accurate detection of bacteriophage activity against Escherichia coli O157:H7 by propidium monoazide real-time PCR.

    Science.gov (United States)

    Liu, Hui; Niu, Yan D; Li, Jinquan; Stanford, Kim; McAllister, Tim A

    2014-01-01

    Conventional methods to determine the efficacy of bacteriophage (phage) for biocontrol of E. coli require several days, due to the need to culture bacteria. Furthermore, cell surface-attached phage particles may lyse bacterial cells during experiments, leading to an overestimation of phage activity. DNA-based real-time quantitative polymerase chain reaction (qPCR) is a fast, sensitive, and highly specific means of enumerating pathogens. However, qPCR may underestimate phage activity due to its inability to distinguish viable from nonviable cells. In this study, we evaluated the suitability of propidium monoazide (PMA), a microbial membrane-impermeable dye that inhibits amplification of extracellular DNA and DNA within dead or membrane-compromised cells as a means of using qPCR to identify only intact E. coli cells that survive phage exposure. Escherichia coli O157:H7 strain R508N and 4 phages (T5-like, T1-like, T4-like, and O1-like) were studied. Results compared PMA-qPCR and direct plating and confirmed that PMA could successfully inhibit amplification of DNA from compromised/damaged cells E. coli O157:H7. Compared to PMA-qPCR, direct plating overestimated (P bacteriophage for biocontrol of E. coli O157:H7.

  1. UV ability to destroy poliovirus end FRNA specific bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Baron, J.; Joret, J.C.; Lesavre, J.; Perrot, J.Y.

    1996-01-01

    In France, the use of ultraviolet radiation to disinfect secondary effluents is only in its initial stage. The aim of this study was to examine the ability of UV to destroy Poliovirus Type 1 and FRNA specific bacteriophages (laboratory MS2 phages and indigenous phages). Concentrated viral solutions were mixed with secondary effluents artificially enriched with suspended solids and then irradiated at various UV dose in a collimated beam. Bacteriological analysis of Escherichia coli and enterococci were performed at the same time. UV were very efficient to kill Poliovirus : Inactivation of 3 and 5 log units were observed respectively at UV doses of 20 and 40 mW/cm{sup 2}. The Poliovirus disinfection rate was almost the same than Escherichia coli. Enterococci were more resistant than E. coli. Inactivation of MS2 bacteriophages was significantly correlated to UV dose following the relationship MS2 Inactivation = 0.047{sup *} Dose + 0,396. At UV dose of 20 mWs/cm{sup 2}, MS2 phages were 2.3 times more resistant to UV than Poliovirus, i.e. they need UV dose 2,3 times greater to be disinfected at the same level. A review of the literature has also shown that viruses more resistant to UV treatment have never been reported. All this would tend to confirm the interest of this group of virus as indicators of the disinfection efficiency of UV, which could indicate, on site, the inactivation of pathogenic viruses. Inactivation rates obtained for FRNA phages proved the good virucidal activity of UV. The inactivation of indigenous FRNA bacteriophages was not correlated with E. coli inactivation. On the other hand, it was correlated with enterococci inactivation. (Author). 23 refs., 7 figs., 4 tabs.

  2. Produtos naturais da ascídia Botrylloides giganteum, das esponjas Verongula gigantea, Ircinia felix, Cliona delitrix e do nudibrânquio Tambja eliora, da costa do Brasil Natural products from the ascidian Botrylloides giganteum, from the sponges Verongula gigantea, Ircinia felix, Cliona delitrix and from the nudibranch Tambja eliora, from the Brazilian coastline

    Directory of Open Access Journals (Sweden)

    Ana Claudia Granato

    2005-03-01

    Full Text Available Two new marine metabolites, 3Z, 6Z, 9Z-dodecatrien-1-ol (1 from the ascidian Botrylloides giganteum and 4H-pyran-2ol acetate from the sponge Ircinia felix (4 are herein reported. The known bromotyrosine compounds, 2-(3,5-dibromo-4-methoxyphenyl-N,N,N-dimethylethanammonium (2 and 2,6-dibromo-4-(2-(trimethylammoniumethylphenol (3, have been isolated from the sponge Verongula gigantea. Serotonin (5 is reported for the first time from the sponge Cliona delitrix, and tambjamines A (15 and D (16 isolated as their respective salts from the nudibranch Tambja eliora. Only tambjamine D presented cytotoxicity against CEM (IC50 12.2 µg/mL and HL60 (IC50 13.2 µg/mL human leukemya cells, MCF-7 breast cancer cells (IC50 13.2 µg/mL, colon HCT-8 cancer cells (IC50 10.1 µg/mL and murine melanoma B16 cancer cells (IC50 6.7 µg/mL.

  3. "China is Playing More and More Important Role in the World" Felix SELINGER-Global CEO of Putzmeister%"中国正在世界上扮演越来越重要的角色"——专访普茨迈斯特全球CEO Felix SELINGER先生

    Institute of Scientific and Technical Information of China (English)

    王刚

    2008-01-01

    @@ 作为一家年产值超过10亿欧元(15亿美元)的全球化公司,普茨迈斯特(Putzmeister)在稠性流体输送机械领域,无论在技术上,还是在生产规模上,始终保持着绝对领先. 面对愈演愈烈的金融危机和逐渐趋向下滑的实体经济增长,普茨迈斯特的一举一动始终是全球用户与同行关注的焦点,记者有幸专访了普茨迈斯特全球CEO Felix SELINGER先生,与他面对面探讨了普茨迈斯特将如何面对这场全世界需要共同应对的危机.

  4. Natural products from the ascidian Botrylloides giganteum, from the sponges Verongula gigantea, Ircinia felix, Cliona delitrix and from the nudibranch Tambja eliora, from the Brazilian coastline; Produtos naturais da ascidia Botrylloides giganteum, das esponjas Verongula gigantea, Ircinia felix, Cliona delitrix e do nudibranquio Tambja eliora, da costa do Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Granato, Ana Claudia; Oliveira, Jaine H.H.L. de; Seleghim, Mirna H.R.; Berlinck, Roberto G.S. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Quimica]. E-mail: rgsberlinck@iqsc.usp.br; Macedo, Mario L.; Ferreira, Antonio G. [Sao Carlos Univ., SP (Brazil). Dept. de Quimica; Rocha, Rosana M. da [Parana Univ., Curitiba, PR (Brazil). Setor de Ciencias Biologicas. Dept. de Zoologia; Hajdu, Eduardo [Universidade Federal, Rio de Janeiro, RJ (Brazil). Museu Nacional; Peixinho, Solange [Bahia Univ., Salvador, BA (Brazil). Dept. de Biologia; Pessoa, Claudia O.; Moraes, Manoel O.; Cavalcanti, Bruno C. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Fisiologia e Farmacologia

    2005-04-01

    Two new marine metabolites, 3Z, 6Z, 9Z-dodecatrien-1-ol (1) from the ascidian Botrylloides giganteum and 4H-pyran-2ol acetate from the sponge Ircinia felix (4) are herein reported. The known bromotyrosine compounds, 2-(3,5-dibromo-4-methoxyphenyl)-N,N,Ndimethylethanammonium (2) and 2,6-dibromo-4-(2-(trimethylammonium)ethyl)phenol (3), have been isolated from the sponge Verongula gigantea. Serotonin (5) is reported for the first time from the sponge Cliona delitrix, and tambjamines A (15) and D (16) isolated as their respective salts from the nudibranch Tambja eliora. Only tambjamine D presented cytotoxicity against CEM (IC{sub 5})0 12.2 {mu}g/mL) and HL60 (IC{sub 50} 13.2 {mu}g/mL) human leukemia cells, MCF-7 breast cancer cells (IC{sub 50} 13.2 {mu}g/mL), colon HCT-8 cancer cells (IC{sub 50} 10.1 {mu}g/mL) and murine melanoma B16 cancer cells (IC{sub 50} 6.7 {mu}g/mL). (author)

  5. Bacteriophages : an underestimated role in human and animal health ?

    Directory of Open Access Journals (Sweden)

    Marianne eDe Paepe

    2014-03-01

    Full Text Available Metagenomic approaches applied to viruses have highlighted their prevalence in almost all microbial ecosystems investigated. In all ecosystems, notably those associated with humans or animals, the viral fraction is dominated by bacteriophages. Whether they contribute to dysbiosis, i.e. the departure from microbiota composition in symbiosis at equilibrium and entry into a state favoring human or animal disease is unknown at present. This review summarizes what has been learnt on phages associated with human and animal microbiota, and focuses on examples illustrating the several ways by which phages may contribute to a shift to pathogenesis, either by modifying population equilibrium, by horizontal transfer, or by modulating immunity.

  6. Back to the future: bacteriophages as promising therapeutic tools.

    Science.gov (United States)

    Domingo-Calap, P; Georgel, P; Bahram, S

    2016-03-01

    Bacteriophages (phages), natural predators of bacteria, are becoming increasingly attractive in medical and pharmaceutical applications. After their discovery almost a century ago, they have been particularly instrumental in the comprehension of basic molecular biology and genetics processes. The more recent emergence of multi-drug-resistant bacteria requires novel therapeutic strategies, and phages are being (re)considered as promising potential antibacterial tools. Furthermore, phages are also used for other purposes, e.g. vaccine production, gene/drug carriers, bacterial detection and typing. These new alternative approaches using phages are of major interest and have allowed unexpected developments, from the decipherment of fundamental biological processes to potential clinical applications.

  7. The role of temperate bacteriophages in bacterial infection.

    Science.gov (United States)

    Davies, Emily V; Winstanley, Craig; Fothergill, Joanne L; James, Chloe E

    2016-03-01

    Bacteriophages are viruses that infect bacteria. There are an estimated 10(31) phage on the planet, making them the most abundant form of life. We are rapidly approaching the centenary of their identification, and yet still have only a limited understanding of their role in the ecology and evolution of bacterial populations. Temperate prophage carriage is often associated with increased bacterial virulence. The rise in use of technologies, such as genome sequencing and transcriptomics, has highlighted more subtle ways in which prophages contribute to pathogenicity. This review discusses the current knowledge of the multifaceted effects that phage can exert on their hosts and how this may contribute to bacterial adaptation during infection.

  8. Molecular Characterization of a Bacteriophage (Chp2) from Chlamydia psittaci

    OpenAIRE

    Liu, B. L.; Everson, J. S.; Fane, B.; Giannikopoulou, P.; Vretou, E.; Lambden, P R; Clarke, I N

    2000-01-01

    Comparisons of the proteome of abortifacient Chlamydia psittaci isolates from sheep by two-dimensional gel electrophoresis identified a novel abundant protein with a molecular mass of 61.4 kDa and an isoelectric point of 6.41. C-terminal sequence analysis of this protein yielded a short peptide sequence that had an identical match to the viral coat protein (VP1) of the avian chlamydiaphage Chp1. Electron microscope studies revealed the presence of a 25-nm-diameter bacteriophage (Chp2) with no...

  9. Re-initiation repair in bacteriophage T4

    International Nuclear Information System (INIS)

    Irradiation of bacteriophage T4 with ultraviolet light induces the formation of pyrimidine dimers in its DNA. These dimers hamper replication of DNA and, to a lesser extent, transcription of DNA after its infection of bacteria. A number of pathways enable phage T4 to multiply dimer-containing DNA. One of these pathways has been named replication repair and is described in this thesis. The properties of two phage strains, unable to perform replication repair, have been studied to obtain a picture of the repair process. The mutations in these strains that affect replication repair have been located on the genomic map of T4. (Auth.)

  10. Application of bacteriophages in post-harvest control of human pathogenic and food spoiling bacteria.

    Science.gov (United States)

    Pérez Pulido, Rubén; Grande Burgos, Maria José; Gálvez, Antonio; Lucas López, Rosario

    2016-10-01

    Bacteriophages have attracted great attention for application in food biopreservation. Lytic bacteriophages specific for human pathogenic bacteria can be isolated from natural sources such as animal feces or industrial wastes where the target bacteria inhabit. Lytic bacteriophages have been tested in different food systems for inactivation of main food-borne pathogens including Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, Salmonella enterica, Shigella spp., Campylobacter jejuni and Cronobacter sakazkii, and also for control of spoilage bacteria. Application of lytic bacteriophages could selectively control host populations of concern without interfering with the remaining food microbiota. Bacteriophages could also be applied for inactivation of bacteria attached to food contact surfaces or grown as biofilms. Bacteriophages may receive a generally recognized as safe status based on their lack of toxicity and other detrimental effects to human health. Phage preparations specific for L. monocytogenes, E. coli O157:H7 and S. enterica serotypes have been commercialized and approved for application in foods or as part of surface decontamination protocols. Phage endolysins have a broader host specificity compared to lytic bacteriophages. Cloned endolysins could be used as natural preservatives, singly or in combination with other antimicrobials such as bacteriocins. PMID:26042353

  11. Isolation and Characterization of Bacteriophages Against Pseudomonas syringae pv. actinidiae Causing Bacterial Canker Disease in Kiwifruit.

    Science.gov (United States)

    Yu, Ji-Gang; Lim, Jeong-A; Song, Yu-Rim; Heu, Sunggi; Kim, Gyoung Hee; Koh, Young Jin; Oh, Chang-Sik

    2016-02-01

    Pseudomonas syringae pv. actinidiae causes bacterial canker disease in kiwifruit. Owing to the prohibition of agricultural antibiotic use in major kiwifruit-cultivating countries, alternative methods need to be developed to manage this disease. Bacteriophages are viruses that specifically infect target bacteria and have recently been reconsidered as potential biological control agents for bacterial pathogens owing to their specificity in terms of host range. In this study, we isolated bacteriophages against P. syringae pv. actinidiae from soils collected from kiwifruit orchards in Korea and selected seven bacteriophages for further characterization based on restriction enzyme digestion patterns of genomic DNA. Among the studied bacteriophages, two belong to the Myoviridae family and three belong to the Podoviridae family, based on morphology observed by transmission electron microscopy. The host range of the selected bacteriophages was confirmed using 18 strains of P. syringae pv. actinidiae, including the Psa2 and Psa3 groups, and some were also effective against other P. syringae pathovars. Lytic activity of the selected bacteriophages was sustained in vitro until 80 h, and their activity remained stable up to 50°C, at pH 11, and under UV-B light. These results indicate that the isolated bacteriophages are specific to P. syringae species and are resistant to various environmental factors, implying their potential use in control of bacterial canker disease in kiwifruits.

  12. Bacteriophages to reduce gut carriage of antibiotic resistant uropathogens with low impact on microbiota composition.

    Science.gov (United States)

    Galtier, Matthieu; De Sordi, Luisa; Maura, Damien; Arachchi, Harindra; Volant, Stevenn; Dillies, Marie-Agnès; Debarbieux, Laurent

    2016-07-01

    Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs) worldwide, causing over 150 million clinical cases annually. There is currently no specific treatment addressing the asymptomatic carriage in the gut of UPEC before they initiate UTIs. This study investigates the efficacy of virulent bacteriophages to decrease carriage of gut pathogens. Three virulent bacteriophages infecting an antibiotic-resistant UPEC strain were isolated and characterized both in vitro and in vivo. A new experimental murine model of gut carriage of E. coli was elaborated and the impact of virulent bacteriophages on colonization levels and microbiota diversity was assessed. A single dose of a cocktail of the three bacteriophages led to a sharp decrease in E. coli levels throughout the gut. We also observed that microbiota diversity was much less affected by bacteriophages than by antibiotics. Therefore, virulent bacteriophages can efficiently target UPEC strains residing in the gut, with potentially profound public health and economic impacts. These results open a new area with the possibility to manipulate specifically the microbiota using virulent bacteriophages, which could have broad applications in many gut-related disorders/diseases and beyond.

  13. Application of bacteriophages in post-harvest control of human pathogenic and food spoiling bacteria.

    Science.gov (United States)

    Pérez Pulido, Rubén; Grande Burgos, Maria José; Gálvez, Antonio; Lucas López, Rosario

    2016-10-01

    Bacteriophages have attracted great attention for application in food biopreservation. Lytic bacteriophages specific for human pathogenic bacteria can be isolated from natural sources such as animal feces or industrial wastes where the target bacteria inhabit. Lytic bacteriophages have been tested in different food systems for inactivation of main food-borne pathogens including Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, Salmonella enterica, Shigella spp., Campylobacter jejuni and Cronobacter sakazkii, and also for control of spoilage bacteria. Application of lytic bacteriophages could selectively control host populations of concern without interfering with the remaining food microbiota. Bacteriophages could also be applied for inactivation of bacteria attached to food contact surfaces or grown as biofilms. Bacteriophages may receive a generally recognized as safe status based on their lack of toxicity and other detrimental effects to human health. Phage preparations specific for L. monocytogenes, E. coli O157:H7 and S. enterica serotypes have been commercialized and approved for application in foods or as part of surface decontamination protocols. Phage endolysins have a broader host specificity compared to lytic bacteriophages. Cloned endolysins could be used as natural preservatives, singly or in combination with other antimicrobials such as bacteriocins.

  14. Pulmonary bacteriophage therapy on Pseudomonas aeruginosa cystic fibrosis strains: first steps towards treatment and prevention.

    Directory of Open Access Journals (Sweden)

    Eric Morello

    Full Text Available Multidrug-resistant bacteria are the cause of an increasing number of deadly pulmonary infections. Because there is currently a paucity of novel antibiotics, phage therapy--the use of specific viruses that infect bacteria--is now more frequently being considered as a potential treatment for bacterial infections. Using a mouse lung-infection model caused by a multidrug resistant Pseudomonas aeruginosa mucoid strain isolated from a cystic fibrosis patient, we evaluated bacteriophage treatments. New bacteriophages were isolated from environmental samples and characterized. Bacteria and bacteriophages were applied intranasally to the immunocompetent mice. Survival was monitored and bronchoalveolar fluids were analysed. Quantification of bacteria, bacteriophages, pro-inflammatory and cytotoxicity markers, as well as histology and immunohistochemistry analyses were performed. A curative treatment (one single dose administrated 2 h after the onset of the infection allowed over 95% survival. A four-day preventive treatment (one single dose resulted in a 100% survival. All of the parameters measured correlated with the efficacy of both curative and preventive bacteriophage treatments. We also showed that in vitro optimization of a bacteriophage towards a clinical strain improved both its efficacy on in vivo treatments and its host range on a panel of 20 P. aeruginosa cystic fibrosis strains. This work provides an incentive to develop clinical studies on pulmonary bacteriophage therapy to combat multidrug-resistant lung infections.

  15. Virulent bacteriophages can target O104:H4 enteroaggregative Escherichia coli in the mouse intestine.

    Science.gov (United States)

    Maura, Damien; Galtier, Matthieu; Le Bouguénec, Chantal; Debarbieux, Laurent

    2012-12-01

    In vivo bacteriophage targeting of enteroaggregative Escherichia coli (EAEC) was assessed using a mouse intestinal model of colonization with the O104:H4 55989Str strain and a cocktail of three virulent bacteriophages. The colonization model was shown to mimic asymptomatic intestinal carriage found in humans. The addition of the cocktail to drinking water for 24 h strongly decreased ileal and weakly decreased fecal 55989Str concentrations in a dose-dependent manner. These decreases in ileal and fecal bacterial concentrations were only transient, since 55989Str concentrations returned to their original levels 3 days later. These transient decreases were independent of the mouse microbiota, as similar results were obtained with axenic mice. We studied the infectivity of each bacteriophage in the ileal and fecal environments and found that 55989Str bacteria in the mouse ileum were permissive to all three bacteriophages, whereas those in the feces were permissive to only one bacteriophage. Our results provide the first demonstration that bacterial permissivity to infection with virulent bacteriophages is not uniform throughout the gut; this highlights the need for a detailed characterization of the interactions between bacteria and bacteriophages in vivo for the further development of phage therapy targeting intestinal pathogens found in the gut of asymptomatic human carriers.

  16. Bacteriophage transport through a fining-upwards sedimentary sequence: laboratory experiments and simulation

    Science.gov (United States)

    Flynn, Raymond; Cornaton, Fabien; Hunkeler, Daniel; Rossi, Pierre

    2004-10-01

    A column containing four concentric layers of progressively finer-grained glass beads (graded column) was used to study the transport of the bacteriophage T7 in water flowing parallel to layering through a fining-upwards (FU) sedimentary structure. By passing a pulse of T7, and a conservative solute tracer upwards through a column packed with a single bead size (uniform column), the capacity of each bead type to attenuate the bacteriophage was determined. Solute and bacteriophage responses were modelled using an analytical solution to the advection-dispersion equation, with first-order kinetic deposition simulating bacteriophage attenuation. Resulting deposition constants for different flow velocities indicated that filtration theory-determined values differed from experimentally determined values by less than 10%. In contrast, the responses of solute and bacteriophage tracers passing upwards through graded columns could not be reproduced with a single analytical solution. However, a flux-weighted summation of four one-dimensional advective-dispersive analytical terms approximated solute breakthrough curves. The prolonged tailing observed in the resulting curve resembled that typically generated from field-based tracer test data, reflecting the potential importance of textural heterogeneity in the transport of dissolved substances in groundwater. Moreover, bacteriophage deposition terms, determined from filtration theory, reproduced the T7 breakthrough curve once desorption and inactivation on grain surfaces were incorporated. To evaluate the effect of FU sequences on mass transport processes in more detail, bacteriophage passage through sequences resembling those sampled from a FU bed in a fluvioglacial gravel pit were carried out using an analogous approach to that employed in the laboratory. Both solute and bacteriophage breakthrough responses resembled those generated from field-based test data and in the graded column experiments. Comparisons with the results

  17. Some aspects of the mechanism of bacteriophage function. Final progress report. [Mechanisms of inactivation of bacteriophages by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Freifelder, D.

    1977-06-12

    Data are summarized from a ten-year study on the radiobiology of phages. The results showed that: phages are inactivated principally by damage to DNA; DNA damage is of two types, base damage and double-strand breakage; double-strand breakage may be lethal because of interruption within a gene, however in phage systems the damage is more fundamental in that only a single DNA fragment is injected into the host; E. coli phage T4 is relatively resistant to inactivation by x-rays; and the rate of production of strand breaks and base damage is nearly the same in bacteriophage and bacteria.

  18. Use of the integration elements encoded by the temperate lactococcal bacteriophage TP901-1

    DEFF Research Database (Denmark)

    Brøndsted, Lone; Hammer, Karin

    1999-01-01

    Previously we showed that only one phage-expressed protein (Orf1), a 425-bp region upstream of the orf1 gene (presumably encoding a promoter), and the attP region are necessary and also sufficient for integration of the bacteriophage TP901-1 genome into the chromosome of Lactococcus lactis subsp......P region seem to be necessary for site-specific integration of the temperate bacteriophage TP901-1. By use of the integrative elements (attP and orf1) expressed by the temperate lactococcal bacteriophage TP901-1, a system for obtaining stable chromosomal single-copy transcriptional fusions in L. lactis...

  19. Complete Genome Sequences of Lytic Bacteriophages of Xanthomonas arboricola pv. juglandis.

    Science.gov (United States)

    Retamales, Julio; Vasquez, Ignacio; Santos, Leonardo; Segovia, Cristopher; Ayala, Manuel; Alvarado, Romina; Nuñez, Pablo; Santander, Javier

    2016-06-02

    Three bacteriophages, f20-Xaj, f29-Xaj, and f30-Xaj, with lytic activity against Xanthomonas arboricola pv. juglandis were isolated from walnut trees (VIII Bío Bío Region, Chile). These lytic bacteriophages have double-stranded DNA (dsDNA) genomes of 43,851 bp, 41,865 bp, and 44,262 bp, respectively. These are the first described bacteriophages with lytic activity against X. arboricola pv. juglandis that can be utilized as biocontrol agents.

  20. [Reconstruction of possible paths of the origin and morphological evolution of bacteriophages].

    Science.gov (United States)

    Letarov, A V

    1998-11-01

    The problem of the origin and evolution of viruses and, in particular, the origin and evolution of bacteriophages is of considerable interest. However, so far, this problem has not been solved with quantitative methods of molecular systematics. In the present study, an attempt to reconstruct the possible paths of appearance and evolution of bacteriophages based on their structural features and morphogenesis, as well as general characteristics of their life cycles and genome organization, was carried out. A scheme describing phylogeny of the main bacteriophage groups and evolution of their life cycles is suggested. Existence of two independently evaluating types of morphogenesis ("budding outward" and "budding inward") is postulated. PMID:10096023

  1. Comparative analysis of two bacteriophages of Xanthomonas arboricola pv. juglandis.

    Science.gov (United States)

    Dömötör, Dóra; Frank, Tamara; Rákhely, Gábor; Doffkay, Zsolt; Schneider, György; Kovács, Tamás

    2016-09-01

    Walnut blight caused by Xanthomonas arboricola pv. juglandis (Xaj) is one of the most frequent infective diseases of walnut, resulting in serious economic losses. One potential solution to control this disease could be the application of bacteriophages. In this study, 24 phages were isolated from soil and walnut aerial tissues infected with Xaj. Two polyvalent bacteriophages, Xaj2 and Xaj24 were chosen for further characterization including their morphological, physiological and genomic analyses. Xaj2 was classified as Siphoviridae whereas Xaj24 belonged to the Podoviridae family. Both phages demonstrated lytic effect on Xaj in laboratory trials. Complete genomes of Xaj2 and Xaj24 were determined. Genomes of Xaj2 and Xaj24 consisted of 49.241 and 44.861 nucleotides encoding 80 and 53 genes, respectively. Comparative genome analyses have revealed that Xaj2 had a unique genome sequence, while Xaj24 was a phiKMV-like phage and it was most similar to the Prado phage which is virulent for Xylella fastidiosa and Xanthomonas spp. In this study, we present the first two complete Xaj phage sequences enabling an insight into the genomics of Xaj phages.

  2. Ecology of Anti-Biofilm Agents I: Antibiotics versus Bacteriophages

    Science.gov (United States)

    Abedon, Stephen T.

    2015-01-01

    Bacteriophages, the viruses that infect bacteria, have for decades been successfully used to combat antibiotic-resistant, chronic bacterial infections, many of which are likely biofilm associated. Antibiotics as anti-biofilm agents can, by contrast, be inefficacious against even genetically sensitive targets. Such deficiencies in usefulness may result from antibiotics, as naturally occurring compounds, not serving their producers, in nature, as stand-alone disruptors of mature biofilms. Anti-biofilm effectiveness by phages, by contrast, may result from a combination of inherent abilities to concentrate lytic antibacterial activity intracellularly via bacterial infection and extracellularly via localized population growth. Considered here is the anti-biofilm activity of microorganisms, with a case presented for why, ecologically, bacteriophages can be more efficacious than traditional antibiotics as medically or environmentally applied biofilm-disrupting agents. Four criteria, it can be argued, generally must be met, in combination, for microorganisms to eradicate biofilms: (1) Furnishing of sufficiently effective antibacterial factors, (2) intimate interaction with biofilm bacteria over extended periods, (3) associated ability to concentrate antibacterial factors in or around targets, and, ultimately, (4) a means of physically disrupting or displacing target bacteria. In nature, lytic predators of bacteria likely can meet these criteria whereas antibiotic production, in and of itself, largely may not. PMID:26371010

  3. Characterization of recombinant bacteriophages containing mosquito ribosomal RNA genes

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y.J.

    1988-01-01

    A family of nine recombinant bacteriophages containing rRNA genes from cultured cells of the mosquito, Aedes albopictus, has been isolated by screening two different genomic DNA libraries - Charon 30 and EMBL 3 using {sup 32}P-labeled 18S and 28S rRNA as probes. These nine recombinant bacteriophages were characterized by restriction mapping, Southern blotting, and S1 nuclease analysis. The 18S rRNA coding region contains an evolutionarily conserved EcoRI site near the 3{prime}-end, and measures 1800 bp. The 28S rRNA genes were divided into {alpha} and {beta} coding regions measuring 1750 bp and 2000 bp, respectively. The gap between these two regions measures about 340 bp. No insertion sequences were found in the rRNA coding regions. The entire rDNA repeat unit had a minimum length of 15.6 kb, including a nontranscribed spacer region. The non-transcribed spacer region of cloned A. albopictus rDNA contained a common series of seven PvuI sites within a 1250 bp region upstream of the 18S rRNA coding region, and a proportion of this region also showed heterogeneity both in the length and in the restriction sites.

  4. Heavy ion induced double strand breaks in bacteria and bacteriophages

    Science.gov (United States)

    Micke, U.; Schäfer, M.; Anton, A.; Horneck, G.; Bücker, H.

    DNA damage induced by heavy ions in bacterial cells and bacteriophages such as Bacillus subtilis, E. coli and Bacteriophage Tl were investigated by analyzing the double strand breaks in the chromosomal DNA. This kind of lesion is considered as one of the main reasons for lethal events. To analyze double strand breaks in long molecules of DNA - up to some Mbp in length - the technique of pulse field agarose gel electrophoresis has been used. This allows the detection of one double strand break per genome. Cell lysis and DNA isolation were performed in small agarose blocks directly. This procedure secured minimum DNA destruction by shearing forces. After running a gel, the DNA was stained with ethidium bromide. The light intensity of ethidium bromide fluorescence for both the outcoming (running) DNA and the remaining intact DNA were measured by scanning. The mean number of double strand breaks was calculated by determining the quotient of these intensities. Strand break induction after heavy ion and X-ray irradiation was compared.

  5. Ecology of Anti-Biofilm Agents I: Antibiotics versus Bacteriophages

    Directory of Open Access Journals (Sweden)

    Stephen T. Abedon

    2015-09-01

    Full Text Available Bacteriophages, the viruses that infect bacteria, have for decades been successfully used to combat antibiotic-resistant, chronic bacterial infections, many of which are likely biofilm associated. Antibiotics as anti-biofilm agents can, by contrast, be inefficacious against even genetically sensitive targets. Such deficiencies in usefulness may result from antibiotics, as naturally occurring compounds, not serving their producers, in nature, as stand-alone disruptors of mature biofilms. Anti-biofilm effectiveness by phages, by contrast, may result from a combination of inherent abilities to concentrate lytic antibacterial activity intracellularly via bacterial infection and extracellularly via localized population growth. Considered here is the anti-biofilm activity of microorganisms, with a case presented for why, ecologically, bacteriophages can be more efficacious than traditional antibiotics as medically or environmentally applied biofilm-disrupting agents. Four criteria, it can be argued, generally must be met, in combination, for microorganisms to eradicate biofilms: (1 Furnishing of sufficiently effective antibacterial factors, (2 intimate interaction with biofilm bacteria over extended periods, (3 associated ability to concentrate antibacterial factors in or around targets, and, ultimately, (4 a means of physically disrupting or displacing target bacteria. In nature, lytic predators of bacteria likely can meet these criteria whereas antibiotic production, in and of itself, largely may not.

  6. Restriction of bacteriophage plaque formation in Streptomyces spp.

    Science.gov (United States)

    Cox, K L; Baltz, R H

    1984-08-01

    Several Streptomyces species that produce restriction endonucleases were characterized for their ability to propagate 10 different broad host range bacteriophages. Each species displayed a different pattern of plaque formation. A restrictionless mutant of S. albus G allowed plaque formation by all 10 phages, whereas the wild-type strain showed plaques with only 2 phages. DNA isolated from three of the phages was analyzed for the presence of restriction sites for Streptomyces species-encoded enzymes, and a very strong correlation was established between the failure to form plaques on Streptomyces species that produced particular restriction enzymes and the presence of the corresponding restriction sites in the phage DNA. Also, the phages that lacked restriction sites in their DNA generally formed plaques on the corresponding restriction endonuclease-producing hosts at high efficiency. The DNAs from the three phages analyzed also generally contained either many or no restriction sites for the Streptomyces species-produced enzymes, suggesting a strong evolutionary trend to either eliminate all or tolerate many restriction sites. The data indicate that restriction plays a major role in host range determination for Streptomyces phages. Analysis of bacteriophage host ranges of many other uncharacterized Streptomyces hosts has identified four relatively nonrestricting hosts, at least two of which may be suitable hosts for gene cloning. The data also suggest that several restriction systems remain to be identified in the genus Streptomyces.

  7. Minimal gene regulatory circuits that can count like bacteriophage lambda.

    Science.gov (United States)

    Avlund, M; Dodd, Ian B; Sneppen, K; Krishna, S

    2009-12-11

    The behavior of living systems is dependent on large dynamical gene regulatory networks (GRNs). However, the functioning of even the smallest GRNs is difficult to predict. The bistable GRN of bacteriophage lambda is able to count to make a decision between lysis and lysogeny on the basis of the number of phages infecting the cell, even though replication of the phage genome eliminates this initial difference. By simulating the behavior of a large number of random transcriptional GRNs, we show that a surprising variety of GRNs can carry out this complex task, including simple CI-Cro-like mutual repression networks. Thus, our study extends the repertoire of simple GRNs. Counterintuitively, the major effect of the addition of CII-like regulation, generally thought to be needed for counting by lambda, was to improve the ability of the networks to complete a simulated prophage induction. Our study suggests that additional regulatory mechanisms to decouple Cro and CII levels may exist in lambda and that infection counting could be widespread among temperate bacteriophages, many of which contain CI-Cro-like circuits. PMID:19796646

  8. PET Imaging and biodistribution of chemically modified bacteriophage MS2.

    Science.gov (United States)

    Farkas, Michelle E; Aanei, Ioana L; Behrens, Christopher R; Tong, Gary J; Murphy, Stephanie T; O'Neil, James P; Francis, Matthew B

    2013-01-01

    The fields of nanotechnology and medicine have merged in the development of new imaging and drug delivery agents based on nanoparticle platforms. As one example, a mutant of bacteriophage MS2 can be differentially modified on the exterior and interior surfaces for the concurrent display of targeting functionalities and payloads, respectively. In order to realize their potential for use in in vivo applications, the biodistribution and circulation properties of this class of agents must first be investigated. A means of modulating and potentially improving the characteristics of nanoparticle agents is the appendage of PEG chains. Both MS2 and MS2-PEG capsids possessing interior DOTA chelators were labeled with (64)Cu and injected intravenously into mice possessing tumor xenografts. Dynamic imaging of the agents was performed using PET-CT on a single animal per sample, and the biodistribution at the terminal time point (24 h) was assessed by gamma counting of the organs ex vivo for 3 animals per agent. Compared to other viral capsids of similar size, the MS2 agents showed longer circulation times. Both MS2 and MS2-PEG bacteriophage behaved similarly, although the latter agent showed significantly less uptake in the spleen. This effect may be attributed to the ability of the PEG chains to mask the capsid charge. Although the tumor uptake of the agents may result from the enhanced permeation and retention (EPR) effect, selective tumor imaging may be achieved in the future by using exterior targeting groups. PMID:23214968

  9. Comparative analysis of two bacteriophages of Xanthomonas arboricola pv. juglandis.

    Science.gov (United States)

    Dömötör, Dóra; Frank, Tamara; Rákhely, Gábor; Doffkay, Zsolt; Schneider, György; Kovács, Tamás

    2016-09-01

    Walnut blight caused by Xanthomonas arboricola pv. juglandis (Xaj) is one of the most frequent infective diseases of walnut, resulting in serious economic losses. One potential solution to control this disease could be the application of bacteriophages. In this study, 24 phages were isolated from soil and walnut aerial tissues infected with Xaj. Two polyvalent bacteriophages, Xaj2 and Xaj24 were chosen for further characterization including their morphological, physiological and genomic analyses. Xaj2 was classified as Siphoviridae whereas Xaj24 belonged to the Podoviridae family. Both phages demonstrated lytic effect on Xaj in laboratory trials. Complete genomes of Xaj2 and Xaj24 were determined. Genomes of Xaj2 and Xaj24 consisted of 49.241 and 44.861 nucleotides encoding 80 and 53 genes, respectively. Comparative genome analyses have revealed that Xaj2 had a unique genome sequence, while Xaj24 was a phiKMV-like phage and it was most similar to the Prado phage which is virulent for Xylella fastidiosa and Xanthomonas spp. In this study, we present the first two complete Xaj phage sequences enabling an insight into the genomics of Xaj phages. PMID:27275846

  10. Tasmancin and lysogenic bacteriophages induced from Erwinia tasmaniensis strains.

    Science.gov (United States)

    Müller, Ina; Lurz, Rudi; Geider, Klaus

    2012-07-25

    Mitomycin C treatment of Erwinia tasmaniensis strains from Australia induced prophages and the expression of bacteriocins. The bacteriocin named tasmancin inhibited E. tasmaniensis strains from South Africa and Germany. A gene cluster with a klebicin-related operon and an immunity protein was detected on plasmid pET46 from E. tasmaniensis strain Et1/99. PCR reactions using primers directed to this region produced signals for several strains originating from Australia, but not for strains isolated in South Africa and Germany. The latter isolates lacked plasmid pET46. Bacteriophages were induced from E. tasmaniensis strains Et88 and Et14/99, both isolates from South-Eastern Australia. These phages formed plaques on several other strains from this region, as well as on E. tasmaniensis strains from South Africa and Germany. Sequencing revealed similarity of phages ϕEt88 and ϕEt14, which shared the host range on E. tasmaniensis strains. Bacteriophages and tasmancin may interfere with the viability of several related E. tasmaniensis strains in the environment of carrier strains.

  11. Phenotypic and genotypic variations within a single bacteriophage species

    Directory of Open Access Journals (Sweden)

    Kulakov Leonid

    2011-03-01

    Full Text Available Abstract Background Although horizontal gene transfer plays a pivotal role in bacteriophage evolution, many lytic phage genomes are clearly shaped by vertical evolution. We investigated the influence of minor genomic deletions and insertions on various phage-related phenotypic and serological properties. Findings We collected ten different isolates of Pseudomonas aeruginosa bacteriophage ϕKMV. All sequenced genomes (42-43 kb, long direct terminal repeats are nearly identical, which intuitively implied strongly similar infections cycles. However, their latent periods vary between 21 and 28 minutes and they are able to lyse between 5 and 58% of a collection of 107 clinical P. aeruginosa strains. We also noted that phages with identical tail structures displayed profound differences in host spectra. Moreover, point mutations in tail and spike proteins were sufficient to evade neutralization by two phage-specific antisera, isolated from rabbits. Conclusion Although all analyzed phages are 83-97% identical at the genome level, they display a surprisingly large variation in various phenotypic properties. The small overlap in host spectrum and their ability to readily escape immune defences against a nearly identical phage are promising elements for the application of these phages in phage therapy.

  12. Vibrio cholerae non-serogroup O1 cystitis.

    OpenAIRE

    Dumler, J.S.; Osterhout, G J; Spangler, J G; Dick, J D

    1989-01-01

    We report a case of a patient who developed cystitis caused by non-serogroup O1 Vibrio cholerae after swimming in the Chesapeake Bay. Treatment was empirical, with complete symptomatic resolution. Genitourinary tract infections by Vibrio spp. are uncommon but should be considered when cystitis occurs after saltwater exposure in appropriate geographic regions.

  13. STUDIES ON THE BACTERIOPHAGE OF D'HERELLE : II. EFFECT OF ALCOHOL ON THE BACTERIOPHAGE OF D'HERELLE.

    Science.gov (United States)

    Bronfenbrenner, J J; Korb, C

    1925-08-31

    When bacteriophage is precipitated by alcohol at room temperature its activity rapidly and progressively decreases until it is totally destroyed, between 6 and 24 hours after exposure. If the percipitation is carried out at 7 degrees C. the destruction of lytic activity is considerably slower; measurable traces may be detected even after 4 weeks exposure to alcohol. Although the major portion of the lytic activity is found in the precipitate, the supernatant alcohol carries a measurable amount of lytic principle which remains active for several days. In all cases the residual lytic activity was found to be transmissible in series. In no instance were we able to observe the non-transmissible action ascribed by d'sHérelle to the enzyme. The persistence of traces of active principle after many weeks of exposure to alcohol at low temperature is not found to be due to the existence in the original filtrate of a fraction relatively resistant to the effect of alcohol. The inactivation of bacteriophage by alcohol seems, therefore, analogous to the alcoholic inactivation of certain enzymes and toxins.

  14. Analysis of the complete DNA sequence of the temperate bacteriophage TP901-1: Evolution, structure, and genome organization of lactococcal bacteriophages

    DEFF Research Database (Denmark)

    Brøndsted, Lone; Østergaard, Solvej; Pedersen, Margit;

    2001-01-01

    A complete analysis of the entire genome of the temperate lactococcal bacteriophage TP901-1 has been performed and the function of 21 of 56 TP901-1-encoded ORFs has been assigned. This knowledge has been used to propose 10 functional modules each responsible for specific functions during bacterio......A complete analysis of the entire genome of the temperate lactococcal bacteriophage TP901-1 has been performed and the function of 21 of 56 TP901-1-encoded ORFs has been assigned. This knowledge has been used to propose 10 functional modules each responsible for specific functions during...... bacteriophage TP901-1 proliferation. Short regions of microhomology in intergenic regions present in several lactococcal bacteriophages and chromosomal fragments of Lactococcus lactis are suggested to be points of exchange of genetic material through homologous recombination. Our results indicate that TP901......-1 may have evolved by homologous recombination between the host chromosome and a mother phage and support the observation that phage remnants as well as prophages located in the Lactococcus chromosome contribute significantly to bacteriophage evolution. Some proteins encoded in the early transcribed...

  15. [The challenge of controlling foodborne diseases: bacteriophages as a new biotechnological tool].

    Science.gov (United States)

    Jorquera, Denisse; Galarce, Nicolás; Borie, Consuelo

    2015-12-01

    Foodborne diseases are an increasing public health issue, in which bacterial pathogens have a transcendental role. To face this situation, the food industry has implemented several control strategies, using in the last decade some biotechnological tools, such as direct application of bacteriophages on food, to effectively control bacterial pathogens. Their bactericidal and safe properties to humans and animals have been widely described in the literature, being nowadays some bacteriophage-based products commercially available. Despite this, there are so many factors that can interfere in their biocontrol effectiveness on food, therefore is essential to consider these factors before their application. Thus, the optimal bacterial reduction will be achieved, which would produce a safer food. This review discusses some factors to consider in the use of bacteriophages as biocontrol agents of foodborne pathogens, including historical background, taxonomy and biological description of bacteriophages, and also advantages, disadvantages, and considerations of food applications.

  16. Stability and in vitro DNA packaging of bacteriophages: effects of dextrans, sugars, and polyols

    Energy Technology Data Exchange (ETDEWEB)

    Serwer, P. (The Univ. of Texas Health Science Center, San Antonio); Masker, W.E.; Allen, J.L.

    1983-02-01

    Attempts were made to increase the efficiency of infectious particle formation during the in vitro assembly of bacteriophage T7 from procapsids and DNA. It was found that dextrans and some smaller, related compounds (sucrose and sorbitol) increase this efficiency by a factor of 8 to 50. Dextrans also inhibited elevated temperature-induced emptying of DNA from bacteriophages T7, P22, and T4, suggesting that the stimulation of assembly is caused, at least in part, by the stabilization of packaged DNA in capsids. The data indicated that the sugars and polyols can slow DNA emptying from bacteriophages at elevated temperature whether they permeate the bacteriophage capsid or not. In contrast, the data suggested that permeation of some particle, probably a capsid, results in inhibition of in vitro T7 assembly.

  17. Bacteriophages for detection and control of bacterial pathogens in food and food-processing environment.

    Science.gov (United States)

    Brovko, Lubov Y; Anany, Hany; Griffiths, Mansel W

    2012-01-01

    This chapter presents recent advances in bacteriophage research and their application in the area of food safety. Section 1 describes general facts on phage biology that are relevant to their application for control and detection of bacterial pathogens in food and environmental samples. Section 2 summarizes the recently acquired data on application of bacteriophages to control growth of bacterial pathogens and spoilage organisms in food and food-processing environment. Section 3 deals with application of bacteriophages for detection and identification of bacterial pathogens. Advantages of bacteriophage-based methods are presented and their shortcomings are discussed. The chapter is intended for food scientist and food product developers, and people in food inspection and health agencies with the ultimate goal to attract their attention to the new developing technology that has a tremendous potential in providing means for producing wholesome and safe food.

  18. BRED: a simple and powerful tool for constructing mutant and recombinant bacteriophage genomes.

    Directory of Open Access Journals (Sweden)

    Laura J Marinelli

    Full Text Available Advances in DNA sequencing technology have facilitated the determination of hundreds of complete genome sequences both for bacteria and their bacteriophages. Some of these bacteria have well-developed and facile genetic systems for constructing mutants to determine gene function, and recombineering is a particularly effective tool. However, generally applicable methods for constructing defined mutants of bacteriophages are poorly developed, in part because of the inability to use selectable markers such as drug resistance genes during viral lytic growth. Here we describe a method for simple and effective directed mutagenesis of bacteriophage genomes using Bacteriophage Recombineering of Electroporated DNA (BRED, in which a highly efficient recombineering system is utilized directly on electroporated phage DNA; no selection is required and mutants can be readily detected by PCR. We describe the use of BRED to construct unmarked gene deletions, in-frame internal deletions, base substitutions, precise gene replacements, and the addition of gene tags.

  19. Bacterial sensing of bacteriophages in communities: the search for the Rosetta stone.

    Science.gov (United States)

    Debarbieux, Laurent

    2014-08-01

    Billions of years of evolution have resulted in microbial viruses and their hosts communicating in such a way that neither of these antagonists can dominate the other definitively. Studies of the molecular mechanisms underlying this dialog, initially in bacteriophages, rapidly identified several of the ways in which bacteria resist bacteriophage infections and bacteriophages defeat bacterial defenses. From an ecological perspective, recent data have raised many questions about the dynamic interactions between bacteria and bacteriophages, the densities of which, in complex microbial populations, are only beginning to be investigated. The next challenge will be determining how the dialog between microbial viruses and their hosts modulates complex ecosystems, such as those found in healthy humans or infected patients.

  20. Improved bacteriophage genome data is necessary for integrating viral and bacterial ecology.

    Science.gov (United States)

    Bibby, Kyle

    2014-02-01

    The recent rise in "omics"-enabled approaches has lead to improved understanding in many areas of microbial ecology. However, despite the importance that viruses play in a broad microbial ecology context, viral ecology remains largely not integrated into high-throughput microbial ecology studies. A fundamental hindrance to the integration of viral ecology into omics-enabled microbial ecology studies is the lack of suitable reference bacteriophage genomes in reference databases-currently, only 0.001% of bacteriophage diversity is represented in genome sequence databases. This commentary serves to highlight this issue and to promote bacteriophage genome sequencing as a valuable scientific undertaking to both better understand bacteriophage diversity and move towards a more holistic view of microbial ecology.

  1. Phylogenetic and functional analysis of the bacteriophage P1 single-stranded DNA-binding protein

    DEFF Research Database (Denmark)

    Bendtsen, Jannick Dyrløv; Nilsson, A.S.; Lehnherr, H.

    2002-01-01

    Bacteriophage P1 encodes a single-stranded DNA-binding protein (SSB-P1), which shows 66% amino acid sequence identity to the SSB protein of the host bacterium Escherichia coli. A phylogenetic analysis indicated that the P1 ssb gene coexists with its E. coli counterpart as an independent unit...... phase. These results reconciled the observed evolutionary conservation with the seemingly redundant presence of ssb genes in many bacteriophages and conjugative plasmids....

  2. Complete Genome Sequences of Four Novel Escherichia coli Bacteriophages Belonging to New Phage Groups

    DEFF Research Database (Denmark)

    Carstens, Alexander B; Kot, Witold; Hansen, Lars H

    2015-01-01

    Here, we describe the sequencing and genome annotations of a set of four Escherichia coli bacteriophages (phages) belonging to newly discovered groups previously consisting of only a single phage and thus expand our knowledge of these phage groups.......Here, we describe the sequencing and genome annotations of a set of four Escherichia coli bacteriophages (phages) belonging to newly discovered groups previously consisting of only a single phage and thus expand our knowledge of these phage groups....

  3. Hexagonally packed DNA within bacteriophage T7 stabilized by curvature stress.

    OpenAIRE

    Odijk, T

    1998-01-01

    A continuum computation is proposed for the bending stress stabilizing DNA that is hexagonally packed within bacteriophage T7. Because the inner radius of the DNA spool is rather small, the stress of the curved DNA genome is strong enough to balance its electrostatic self-repulsion so as to form a stable hexagonal phase. The theory is in accord with the microscopically determined structure of bacteriophage T7 filled with DNA within the experimental margin of error.

  4. A Fluoroquinolone Induces a Novel Mitogen-Encoding Bacteriophage in Streptococcus canis

    OpenAIRE

    Ingrey, Keely T.; Ren, Jun; Prescott, John F.

    2003-01-01

    This study investigated whether the recently recognized emergence of canine streptococcal toxic shock syndrome (STSS) and necrotizing fasciitis (NF) might be partly attributed to the use of fluoroquinolones to treat Streptococcus canis infections in dogs. Both mitomycin and the fluoroquinolone enrofloxacin caused bacteriophage-induced lysis of S. canis strain 34, an isolate from a case of canine STSS and NF. Fluoroquinolone-evoked, bacteriophage-induced lysis occurred over a range of concentr...

  5. BRED: A Simple and Powerful Tool for Constructing Mutant and Recombinant Bacteriophage Genomes

    OpenAIRE

    Marinelli, Laura J.; Mariana Piuri; Zuzana Swigonová; Amrita Balachandran; Oldfield, Lauren M.; van Kessel, Julia C.; Hatfull, Graham F.

    2008-01-01

    Advances in DNA sequencing technology have facilitated the determination of hundreds of complete genome sequences both for bacteria and their bacteriophages. Some of these bacteria have well-developed and facile genetic systems for constructing mutants to determine gene function, and recombineering is a particularly effective tool. However, generally applicable methods for constructing defined mutants of bacteriophages are poorly developed, in part because of the inability to use selectable m...

  6. Genetic diversity among five T4-like bacteriophages

    Directory of Open Access Journals (Sweden)

    Bertrand Claire

    2006-05-01

    Full Text Available Abstract Background Bacteriophages are an important repository of genetic diversity. As one of the major constituents of terrestrial biomass, they exert profound effects on the earth's ecology and microbial evolution by mediating horizontal gene transfer between bacteria and controlling their growth. Only limited genomic sequence data are currently available for phages but even this reveals an overwhelming diversity in their gene sequences and genomes. The contribution of the T4-like phages to this overall phage diversity is difficult to assess, since only a few examples of complete genome sequence exist for these phages. Our analysis of five T4-like genomes represents half of the known T4-like genomes in GenBank. Results Here, we have examined in detail the genetic diversity of the genomes of five relatives of bacteriophage T4: the Escherichia coli phages RB43, RB49 and RB69, the Aeromonas salmonicida phage 44RR2.8t (or 44RR and the Aeromonas hydrophila phage Aeh1. Our data define a core set of conserved genes common to these genomes as well as hundreds of additional open reading frames (ORFs that are nonconserved. Although some of these ORFs resemble known genes from bacterial hosts or other phages, most show no significant similarity to any known sequence in the databases. The five genomes analyzed here all have similarities in gene regulation to T4. Sequence motifs resembling T4 early and late consensus promoters were observed in all five genomes. In contrast, only two of these genomes, RB69 and 44RR, showed similarities to T4 middle-mode promoter sequences and to the T4 motA gene product required for their recognition. In addition, we observed that each phage differed in the number and assortment of putative genes encoding host-like metabolic enzymes, tRNA species, and homing endonucleases. Conclusion Our observations suggest that evolution of the T4-like phages has drawn on a highly diverged pool of genes in the microbial world. The T4

  7. Access to bacteriophage therapy: discouraging experiences from the human cell and tissue legal framework.

    Science.gov (United States)

    Verbeken, G; Huys, I; De Vos, D; De Coninck, A; Roseeuw, D; Kets, E; Vanderkelen, A; Draye, J P; Rose, T; Jennes, S; Ceulemans, C; Pirnay, J P

    2016-02-01

    Cultures of human epithelial cells (keratinocytes) are used as an additional surgical tool to treat critically burnt patients. Initially, the production environment of keratinocyte grafts was regulated exclusively by national regulations. In 2004, the European Tissues and Cells Directive 2004/23/EC (transposed into Belgian Law) imposed requirements that resulted in increased production costs and no significant increase in quality and/or safety. In 2007, Europe published Regulation (EC) No. 1394/2007 on Advanced Therapy Medicinal Products. Overnight, cultured keratinocytes became (arguably) 'Advanced' Therapy Medicinal Products to be produced as human medicinal products. The practical impact of these amendments was (and still is) considerable. A similar development appears imminent in bacteriophage therapy. Bacteriophages are bacterial viruses that can be used for tackling the problem of bacterial resistance development to antibiotics. Therapeutic natural bacteriophages have been in clinical use for almost 100 years. Regulators today are framing the (re-)introduction of (natural) bacteriophage therapy into 'modern western' medicine as biological medicinal products, also subject to stringent regulatory medicinal products requirements. In this paper, we look back on a century of bacteriophage therapy to make the case that therapeutic natural bacteriophages should not be classified under the medicinal product regulatory frames as they exist today. It is our call to authorities to not repeat the mistake of the past.

  8. [Determination of Azospirillum Brasilense Cells With Bacteriophages via Electrooptical Analysis of Microbial Suspensions].

    Science.gov (United States)

    Gulii, O I; Karavayeva, O A; Pavlii, S A; Sokolov, O I; Bunin, V D; Ignatov, O V

    2015-01-01

    The dependence-of changes in the electrooptical properties of Azospirillum brasilense cell suspension Sp7 during interaction with bacteriophage ΦAb-Sp7 on the number and time of interactions was studied. Incubation of cells with bacteriophage significantly changed the electrooptical signal within one minute. The selective effect of bacteriophage ΦAb on 18 strains of bacteria of the genus Azospirillum was studied: A. amazonense Ami4, A. brasilense Sp7, Cd, Sp107, Sp245, Jm6B2, Brl4, KR77, S17, S27, SR55, SR75, A. halopraeferans Au4, A. irakense KBC1, K A3, A. lipoferum Sp59b, SR65 and RG20a. We determined the limit of reliable determination of microbial cells infected with bacteriophage: - 10(4) cells/mL. The presence of foreign cell cultures of E. coli B-878 and E. coli XL-1 did not complicate the detection of A brasilense Sp7 cells with the use of bacteriophage ΦAb-Sp7. The results demonstrated that bacteriophage (ΦAb-Sp7 can be used for the detection of Azospirillum microbial cells via t electrooptical analysis of cell suspensions.

  9. Genomic variants of bacteriophages against Salmonella enterica serovar Enteritidis with potential application in the poultry industry

    Directory of Open Access Journals (Sweden)

    J Robeson

    2008-09-01

    Full Text Available Salmonella enterica serovar Enteritidis (SE is a prevalent gastrointestinal pathogen worldwide, threatening both animal and human health. In the latter, disease is associated to the consumption of SE-contaminated products from the poultry industry. The control of SE infection is largely based on the use of antibiotics and vaccines, but the use of lytic bacteriophages is re-emerging as an additional strategy for SE control. In fact, a number of recent reports point to the adequacy of bacteriophage as an efficient prophylactic or therapeutic countermeasure to SE infections. However, less attention has been focused on the basic biology of these bacteriophages. Here we report on three bacteriophages (f18, IF1 and EST2 that share a common viral particle morphology but are genomic variants as judged by their EcoRI DNA restriction patterns. Furthermore, they differ in their lytic capability towards SE, being EST2 the most efficient. They show a very narrow host range, efficiently infecting only SE strains. In terms of stability in various suspension media, including distilled water, all three bacteriophages remained viable, without noticeable decay in titer for at least 15 days at 25ºC. These results suggest the suitability of the tested bacteriophages as SE-controlling agents in the poultry industry.

  10. Detection of Bacterial Wilt Pathogen and Isolation of Its Bacteriophage from Banana in Lumajang Area, Indonesia

    Directory of Open Access Journals (Sweden)

    Hardian Susilo Addy

    2016-01-01

    Full Text Available Bacterial wilt disease on banana is an important disease in Lumajang District and causes severe yield loss. Utilizing bacteriophage as natural enemy of pathogenic bacteria has been widely known as one of the control strategies. This research was aimed at determining the causing agent of bacterial wilt on banana isolated from Lumajang area, to obtain wide-host range bacteriophages against bacterial wilt pathogen and to know the basic characteristic of bacteriophages, particularly its nucleic acid type. Causative agent of bacterial wilt was isolated from symptomatic banana trees from seven districts in Lumajang area on determinative CPG plates followed by rapid detection by PCR technique using specific pair-primer. Bacteriophages were also isolated from soil of infected banana crop in Sukodono District. Morphological observation showed that all bacterial isolates have similar characteristic as common bacterial wilt pathogen, Ralstonia solanacearum. In addition, detection of FliC region in all isolates confirmed that all isolates were R. solanacearum according to the presence of 400 bp of FliC DNA fragment. Moreover, two bacteriophages were obtained from this experiment (ϕRSSKD1 and ϕRSSKD2, which were able to infect all nine R. solanacearum isolates. Nucleic acid analysis showed that the nucleic acid of bacteriophages was DNA (deoxyribonucleic acid.

  11. Characterization and Detection of Endolysin Gene from Three Acinetobacter baumannii Bacteriophages Isolated from Sewage Water.

    Science.gov (United States)

    Kitti, Thawatchai; Thummeepak, Rapee; Thanwisai, Aunchalee; Boonyodying, Kamala; Kunthalert, Duangkamol; Ritvirool, Pannika; Sitthisak, Sutthirat

    2014-12-01

    Acinetobacter baumannii is an opportunistic pathogen that exists in hospital environments. The emergence of multidrug resistant A. baumannii (MDRAB) has been reported worldwide. It is necessary to find a novel and effective treatment for MDRAB infection. In this study, three bacteriophages, designated as ØABP-01, ØABP-02 and ØABP-04 were selected for analysis. Transmission electron microscopy showed that bacteriophage ØABP-01 belonged to the Podoviridae family and bacteriophage ØABP-02 and ØABP-04 are classified into the family Myoviridae. ØABP-01 had the widest host range. ØABP-01, ØABP-02 and ØABP-04 exhibited a latent period of 15, 20 and 20 min. The burst sizes of the three bacteriophages were 110, 120 and 150 PFU/cell. DNA restriction analysis using EcoRI, HindIII, PstI, SphI, BamHI and SmaI showed different DNA fragment patterns between the three bacteriophages. ØABP-01 and ØABP-04 was positive for the endolysin gene as determined by PCR. In conclusion, bacteriophage ØABP-01 showed broad host-specificity, good lytic activity and a short latency period, making it an appropriate candidate for studying the control and diagnosis associated with MDRAB infections.

  12. A simple and novel modification of comet assay for determination of bacteriophage mediated bacterial cell lysis.

    Science.gov (United States)

    Khairnar, Krishna; Sanmukh, Swapnil; Chandekar, Rajshree; Paunikar, Waman

    2014-07-01

    The comet assay is the widely used method for in vitro toxicity testing which is also an alternative to the use of animal models for in vivo testing. Since, its inception in 1984 by Ostling and Johansson, it is being modified frequently for a wide range of application. In spite of its wide applicability, unfortunately there is no report of its application in bacteriophages research. In this study, a novel application of comet assay for the detection of bacteriophage mediated bacterial cell lysis was described. The conventional methods in bacteriophage research for studying bacterial lysis by bacteriophages are plaque assay method. It is time consuming, laborious and costly. The lytic activity of bacteriophage devours the bacterial cell which results in the release of bacterial genomic material that gets detected by ethidium bromide staining method by the comet assay protocol. The objective of this study was to compare efficacy of comet assay with different assay used to study phage mediated bacterial lysis. The assay was performed on culture isolates (N=80 studies), modified comet assay appear to have relatively higher sensitivity and specificity than other assay. The results of the study showed that the application of comet assay can be an economical, time saving and less laborious alternative to conventional plaque assay for the detection of bacteriophage mediated bacterial cell lysis.

  13. A simple and novel modification of comet assay for determination of bacteriophage mediated bacterial cell lysis.

    Science.gov (United States)

    Khairnar, Krishna; Sanmukh, Swapnil; Chandekar, Rajshree; Paunikar, Waman

    2014-07-01

    The comet assay is the widely used method for in vitro toxicity testing which is also an alternative to the use of animal models for in vivo testing. Since, its inception in 1984 by Ostling and Johansson, it is being modified frequently for a wide range of application. In spite of its wide applicability, unfortunately there is no report of its application in bacteriophages research. In this study, a novel application of comet assay for the detection of bacteriophage mediated bacterial cell lysis was described. The conventional methods in bacteriophage research for studying bacterial lysis by bacteriophages are plaque assay method. It is time consuming, laborious and costly. The lytic activity of bacteriophage devours the bacterial cell which results in the release of bacterial genomic material that gets detected by ethidium bromide staining method by the comet assay protocol. The objective of this study was to compare efficacy of comet assay with different assay used to study phage mediated bacterial lysis. The assay was performed on culture isolates (N=80 studies), modified comet assay appear to have relatively higher sensitivity and specificity than other assay. The results of the study showed that the application of comet assay can be an economical, time saving and less laborious alternative to conventional plaque assay for the detection of bacteriophage mediated bacterial cell lysis. PMID:24681053

  14. Isolation, characterization, and application of bacteriophages for Salmonella spp. biocontrol in pigs.

    Science.gov (United States)

    Albino, Luiz A A; Rostagno, Marcos H; Húngaro, Humberto M; Mendonça, Regina C S

    2014-08-01

    Foodborne illness due to Salmonella-contaminated pork products is an important public health problem, causing significant economic losses worldwide. The use of bacteriophages is a potential intervention tool that has attracted interest for the control of foodborne pathogens. The objective of this study was to detect the presence of Salmonella in commercial pig farms and to isolate specific autochthonous bacteriophages against Salmonella Typhimurium, to characterize them and to evaluate their lytic capacity against Salmonella Typhimurium in vivo and in vitro. Salmonella was isolated on 50% (4/8) of the farms, with serotype Typhimurium being the most prevalent, detected in 48.2% of samples (13/27). The isolated Salmonella Typhimurium bacteriophages belong to the Podoviridae family, were active against serotypes Abony, Enteritidis, Typhi, and Typhimurium, but not against serotypes Arizonae, Cholerasuis, Gallinarum, and Pullorum. In in vitro tests, bacteriophage at 10(7) PFU/mL and 10(9) PFU/mL significantly reduced (pbacteriophages, Salmonella was identified in 93.3% (28/30) of the fecal samples from the pigs inoculated with 10(6) CFU/mL, and only in 56.6% (17/30) after the treatment consisting of oral administration of the pool of the bacteriophages after the fasting period, simulating a common preslaughter practice. These results indicate that the pool of bacteriophages administered was capable of reducing the colonization of Salmonella in pigs.

  15. Isolation of Dickeya dadantii strains from potato disease and biocontrol by their bacteriophages.

    Science.gov (United States)

    Soleimani-Delfan, Abbas; Etemadifar, Zahra; Emtiazi, Giti; Bouzari, Majid

    2015-01-01

    One of the most economically important bacterial pathogens of plants and plant products is Dickeya dadantii. This bacterium causes soft rot disease in tubers and other parts of the potato and other plants of the Solanaceae family. The application of restricted host range bacteriophages as biocontrol agents has recently gained widespread interest. This study purposed to isolate the infectious agent of the potato and evaluate its biocontrol by bacteriophages. Two phytopathogenic strains were isolated from infected potatoes, identified based on biochemical and 16S rRNA gene sequencing, and submitted to GenBank as D. dadantii strain pis3 (accession no. HQ423668) and D. dadantii strain sip4 (accession no. HQ423669). Their bacteriophages were isolated from Caspian Sea water by enriching the water filtrate with D. dadantii strains as hosts using spot or overlay methods. On the basis of morphotypes, the isolated bacteriophages were identified as members of the Myoviridae and Siphoviridae families and could inhibit the growth of antibiotic resistant D. dadantii strains in culture medium. Moreover, in Dickeya infected plants treated with bacteriophage, no disease progression was detected. No significant difference was seen between phage-treated and control plants. Thus, isolated bacteriophages can be suggested for the biocontrol of plant disease caused by Dickeya strains.

  16. Bacteriophage Resistance Mechanisms in the Fish Pathogen Flavobacterium psychrophilum: Linking Genomic Mutations to Changes in Bacterial Virulence Factors

    DEFF Research Database (Denmark)

    Castillo, Daniel; Christiansen, Rói Hammershaimb; Dalsgaard, Inger;

    2015-01-01

    Flavobacterium psychrophilum is an important fish pathogen in salmonid aquaculture worldwide. Due to increased antibiotic resistance, pathogen control using bacteriophages has been explored as a possible alternative treatment. However, the effective use of bacteriophages in pathogen control...... resistance and the genetic modifications were supported by direct measurements of bacteriophage adsorption rates, biofilm formation, and secretion of extracellular enzymes, which were all impaired in the resistant strains, probably due to superficial structural changes. The clustered regularly interspaced...

  17. Clinical manifestations of non-O1 Vibrio cholerae infections.

    Directory of Open Access Journals (Sweden)

    Yen-Ting Chen

    Full Text Available BACKGROUND: Infections caused by non-O1 Vibrio cholera are uncommon. The aim of our study was to investigate the clinical and microbiological characteristics of patients with non-O1 V. cholera infections. METHODS: The clinical charts of all patients with non-O1 V. cholera infections and who were treated in two hospitals in Taiwan were retrospectively reviewed. RESULTS: From July 2009 to June 2014, a total of 83 patients with non-O1 V. cholera infections were identified based on the databank of the bacteriology laboratories of two hospitals. The overall mean age was 53.3 years, and men comprised 53 (63.9% of the patients. Liver cirrhosis and diabetes mellitus were the two most common underlying diseases, followed by malignancy. The most common type of infection was acute gastroenteritis (n = 45, 54.2%, followed by biliary tract infection (n = 12, 14.5% and primary bacteremia (n = 11, 13.3%. Other types of infection, such as peritonitis (n = 5, 6.0%, skin and soft tissue infection (SSTI (n = 5, 6.0%, urinary tract infection (n = 3, 3.6% and pneumonia (2, 2.4%, were rare. July and June were the most common months of occurrence of V. cholera infections. The overall in-hospital mortality of 83 patients with V. cholera infections was 7.2%, but it was significantly higher for patients with primary bacteremia, hemorrhage bullae, acute kidney injury, acute respiratory failure, or admission to an ICU. Furthermore, multivariate analysis showed that in-hospital mortality was significantly associated with acute respiratory failure (odds ratio, 60.47; 95% CI, 4.79-763.90, P = 0.002. CONCLUSIONS: Non-O1 V. cholera infections can cause protean disease, especially in patients with risk factors and during warm-weather months. The overall mortality of 83 patients with non-O1 V. cholera infections was only 7.2%; however, this value varied among different types of infection.

  18. Characterization of a thermophilic bacteriophage of Geobacillus kaustophilus.

    Science.gov (United States)

    Marks, Timothy J; Hamilton, Paul T

    2014-10-01

    GBK2 is a bacteriophage, isolated from a backyard compost pile, that infects the thermophile Geobacillus kaustophilus. GBK2 has a circularly permuted genome of 39,078 bp with a G+C content of 43 %. Annotation of the genome reveals 62 putative open reading frames (ORFs), 25 of which (40.3 %) show homology to known proteins and 37 of which (59.7 %) are proteins with unknown functions. Twelve of the identified ORFs had the greatest homology to genes from the phage SPP1, a phage that infects the mesophile Bacillus subtilis. The overall genomic arrangement of GBK2 is similar to that of SPP1, with the majority of GBK2 SPP1-like genes coding for proteins involved in DNA replication and metabolism.

  19. Capstan Friction Model for DNA Ejection from Bacteriophages

    Science.gov (United States)

    Ghosal, Sandip

    2012-12-01

    Bacteriophages infect cells by attaching to the outer membrane and injecting their DNA into the cell. The phage DNA is then transcribed by the cell’s transcription machinery. A number of physical mechanisms by which DNA can be translocated from the phage capsid into the cell have been identified. A fast ejection driven by the elastic and electrostatic potential energy of the compacted DNA within the viral capsid appears to be used by most phages, at least to initiate infection. In recent in vitro experiments, the speed of DNA translocation from a λ phage capsid has been measured as a function of ejected length over the entire duration of the event. Here, a mechanical model is proposed that is able to explain the observed dependence of exit velocity on ejected length, and that is also consistent with the accepted picture of the geometric arrangement of DNA within the viral capsid.

  20. Modelling the interaction between bacteriophages and their bacterial hosts.

    Science.gov (United States)

    Beke, Gabor; Stano, Matej; Klucar, Lubos

    2016-09-01

    A mathematical model simulating the interaction between bacteriophages and their bacterial hosts has been developed. It is based on other known models describing this type of interaction, enhanced with an ability to model the system influenced by other environmental factor such as pH and temperature. This could be used for numerous estimations of growth rate, when the pH and/or the temperature of the environment are not constant. The change of pH or the temperature greatly affects the specific growth rate which has an effect on the final results of the simulation. Since the model aims on practical application and easy accessibility, an interactive website has been developed where users can run simulations with their own parameters and easily calculate and visualise the result of simulation. The web simulation is accessible at the URL http://www.phisite.org/model.

  1. The Allosteric Switching Mechanism in Bacteriophage MS2

    CERN Document Server

    Perkett, Matthew R

    2015-01-01

    In this article we use all-atom simulations to elucidate the mechanisms underlying conformational switching and allostery within the coat protein of the bacteriophage MS2. Assembly of most icosahedral virus capsids requires that the capsid protein adopt different conformations at precise locations within the capsid. It has been shown that a 19 nucleotide stem loop (TR) from the MS2 genome acts as an allosteric effector, guiding conformational switching of the coat protein during capsid assembly. Since the principal conformational changes occur far from the TR binding site, it is important to understand the molecular mechanism underlying this allosteric communication. To this end, we use all-atom simulations with explicit water combined with a path sampling technique to sample the MS2 coat protein conformational transition, in the presence and absence of TR-binding. The calculations find that TR binding strongly alters the transition free energy profile, leading to a switch in the favored conformation. We disc...

  2. Role of osmotic and hydrostatic pressures in bacteriophage genome ejection

    CERN Document Server

    Lemay, Serge G; Molineux, Ian J

    2012-01-01

    A critical step in the bacteriophage life cycle is genome ejection into host bacteria. The ejection process for double-stranded DNA phages has been studied thoroughly \\textit{in vitro}, where after triggering with the cellular receptor the genome ejects into a buffer. The experimental data have been interpreted in terms of the decrease in free energy of the densely packed DNA associated with genome ejection. Here we detail a simple model of genome ejection in terms of the hydrostatic and osmotic pressures inside the phage, a bacterium, and a buffer solution/culture medium. We argue that the hydrodynamic flow associated with the water movement from the buffer solution into the phage capsid and further drainage into the bacterial cytoplasm, driven by the osmotic gradient between the bacterial cytoplasm and culture medium, provides an alternative mechanism for phage genome ejection \\textit{in vivo}; the mechanism is perfectly consistent with phage genome ejection \\textit{in vitro}.

  3. Capstan friction model for DNA ejection from bacteriophages

    CERN Document Server

    Ghosal, Sandip

    2013-01-01

    Bacteriophages infect cells by attaching to the outer membrane and injecting their DNA into the cell.The phage DNA is then transcribed by the cell's transcription machinery.A number of physical mechanisms by which DNA can be translocated from the phage capsid into the cell have been identified. A fast ejection driven by the elastic and electrostatic potential energy of the compacted DNA within the viral capsid appears to be used by most phages, at least to initiate infection.In recent in vitro experiments, the speed of DNA translocation from a lambda phage capsid has been measured as a function of ejected length over the entire duration of the event.Here a mechanical model is proposed that is able to explain the observed dependence of exit velocity on ejected length, and that is also consistent with the accepted picture of the geometric arrangement of DNA within the viral capsid.

  4. Bacteriophages-potential for application in wastewater treatment processes

    Energy Technology Data Exchange (ETDEWEB)

    Withey, S. [School of Water Sciences, Cranfield University, Cranfield, Bedfordshire, MK43 0AL (United Kingdom); Cartmell, E. [School of Water Sciences, Cranfield University, Cranfield, Bedfordshire, MK43 0AL (United Kingdom)]. E-mail: e.cartmell@cranfield.ac.uk; Avery, L.M. [School of Water Sciences, Cranfield University, Cranfield, Bedfordshire, MK43 0AL (United Kingdom); Stephenson, T. [School of Water Sciences, Cranfield University, Cranfield, Bedfordshire, MK43 0AL (United Kingdom)

    2005-03-01

    Bacteriophages are viruses that infect and lyse bacteria. Interest in the ability of phages to control bacterial populations has extended from medical applications into the fields of agriculture, aquaculture and the food industry. Here, the potential application of phage techniques in wastewater treatment systems to improve effluent and sludge emissions into the environment is discussed. Phage-mediated bacterial mortality has the potential to influence treatment performance by controlling the abundance of key functional groups. Phage treatments have the potential to control environmental wastewater process problems such as: foaming in activated sludge plants; sludge dewaterability and digestibility; pathogenic bacteria; and to reduce competition between nuisance bacteria and functionally important microbial populations. Successful application of phage therapy to wastewater treatment does though require a fuller understanding of wastewater microbial community dynamics and interactions. Strategies to counter host specificity and host cell resistance must also be developed, as should safety considerations regarding pathogen emergence through transduction.

  5. Targeting glioblastoma via intranasal administration of Ff bacteriophages

    Science.gov (United States)

    Dor-On, Eyal; Solomon, Beka

    2015-01-01

    Bacteriophages (phages) are ubiquitous viruses that control the growth and diversity of bacteria. Although they have no tropism to mammalian cells, accumulated evidence suggests that phages are not neutral to the mammalian macro-host and can promote immunomodulatory and anti-tumorigenic activities. Here we demonstrate that Ff phages that do not display any proteins or peptides could inhibit the growth of subcutaneous glioblastoma tumors in mice and that this activity is mediated in part by lipopolysaccharide molecules attached to their virion. Using the intranasal route, a non-invasive approach to deliver therapeutics directly to the CNS, we further show that phages rapidly accumulate in the brains of mice and could attenuate progression of orthotopic glioblastoma. Taken together, this study provides new insight into phages non-bacterial activities and demonstrates the feasibility of delivering Ff phages intranasally to treat brain malignancies. PMID:26074908

  6. Targeting glioblastoma via intranasal administration of Ff bacteriophages

    Directory of Open Access Journals (Sweden)

    Eyal eDor-On

    2015-05-01

    Full Text Available Bacteriophages (phages are ubiquitous viruses that control the growth and diversity of bacteria. Although they have no tropism to mammalian cells, accumulated evidence suggests that phages are not neutral to the mammalian macro-host and can promote immunomodulatory and anti-tumorigenic activities. Here we demonstrate that Ff phages that do not display any proteins or peptides could inhibit the growth of subcutaneous glioblastoma tumors in mice and that this activity is mediated in part by lipopolysaccharide molecules attached to their virion. Using the intranasal route, a non-invasive approach to deliver therapeutics directly to the CNS, we further show that phages rapidly accumulate in the brains of mice and could attenuate progression of orthotopic glioblastoma. Taken together, this study provides new insight into phages non-bacterial activities and demonstrates the feasibility of delivering Ff phages intranasally to treat brain malignancies.

  7. Bacteriophages in clinical samples can interfere with microbiological diagnostic tools.

    Science.gov (United States)

    Brown-Jaque, Maryury; Muniesa, Maite; Navarro, Ferran

    2016-09-09

    Bacteriophages are viruses that infect bacteria, and they are found everywhere their bacterial hosts are present, including the human body. To explore the presence of phages in clinical samples, we assessed 65 clinical samples (blood, ascitic fluid, urine, cerebrospinal fluid, and serum). Infectious tailed phages were detected in >45% of ascitic fluid and urine samples. Three examples of phage interference with bacterial isolation were observed. Phages prevented the confluent bacterial growth required for an antibiogram assay when the inoculum was taken from an agar plate containing lysis plaques, but not when taken from a single colony in a phage-free area. In addition, bacteria were isolated directly from ascitic fluid, but not after liquid enrichment culture of the same samples, since phage propagation lysed the bacteria. Lastly, Gram-negative bacilli observed in a urine sample did not grow on agar plates due to the high densities of infectious phages in the sample.

  8. Application of bacteriophages for detection of foodborne pathogens.

    Science.gov (United States)

    Schmelcher, Mathias; Loessner, Martin J

    2014-01-01

    Bacterial contamination of food products presents a challenge for the food industry and poses a high risk for the consumer. Despite increasing awareness and improved hygiene measures, foodborne pathogens remain a threat for public health, and novel methods for detection of these organisms are needed. Bacteriophages represent ideal tools for diagnostic assays because of their high target cell specificity, inherent signal-amplifying properties, easy and inexpensive production, and robustness. Every stage of the phage lytic multiplication cycle, from the initial recognition of the host cell to the final lysis event, may be harnessed in several ways for the purpose of bacterial detection. Besides intact phage particles, phage-derived affinity molecules such as cell wall binding domains and receptor binding proteins can serve for this purpose. This review provides an overview of existing phage-based technologies for detection of foodborne pathogens, and highlights the most recent developments in this field, with particular emphasis on phage-based biosensors.

  9. Bacteriophages in clinical samples can interfere with microbiological diagnostic tools

    Science.gov (United States)

    Brown-Jaque, Maryury; Muniesa, Maite; Navarro, Ferran

    2016-01-01

    Bacteriophages are viruses that infect bacteria, and they are found everywhere their bacterial hosts are present, including the human body. To explore the presence of phages in clinical samples, we assessed 65 clinical samples (blood, ascitic fluid, urine, cerebrospinal fluid, and serum). Infectious tailed phages were detected in >45% of ascitic fluid and urine samples. Three examples of phage interference with bacterial isolation were observed. Phages prevented the confluent bacterial growth required for an antibiogram assay when the inoculum was taken from an agar plate containing lysis plaques, but not when taken from a single colony in a phage-free area. In addition, bacteria were isolated directly from ascitic fluid, but not after liquid enrichment culture of the same samples, since phage propagation lysed the bacteria. Lastly, Gram-negative bacilli observed in a urine sample did not grow on agar plates due to the high densities of infectious phages in the sample. PMID:27609086

  10. Properties of the streptomycete temperate bacteriophage FP43.

    Science.gov (United States)

    Hahn, D R; McHenney, M A; Baltz, R H

    1991-06-01

    FP43 is a temperate bacteriophage for Streptomyces griseofuscus that forms plaques on many Streptomyces species. FP43 virions contain 56 kb of double-strand DNA that is circularly permuted and terminally redundant, and contains 65% G + C. A physical map of the FP43 genome was constructed, and the origin for headful packaging (pac) was localized to an 8.8-kb region of the genome (hft) that mediates high-frequency transduction by FP43 of plasmid pRHB101. The phage attachment site (attP), a replication origin (rep), a region that inhibits plaque formation (pin), and a 3-kb deletion (rpt) that caused a 100-fold reduction in plasmid transduction were mapped.

  11. Application of bacteriophages for detection of foodborne pathogens.

    Science.gov (United States)

    Schmelcher, Mathias; Loessner, Martin J

    2014-01-01

    Bacterial contamination of food products presents a challenge for the food industry and poses a high risk for the consumer. Despite increasing awareness and improved hygiene measures, foodborne pathogens remain a threat for public health, and novel methods for detection of these organisms are needed. Bacteriophages represent ideal tools for diagnostic assays because of their high target cell specificity, inherent signal-amplifying properties, easy and inexpensive production, and robustness. Every stage of the phage lytic multiplication cycle, from the initial recognition of the host cell to the final lysis event, may be harnessed in several ways for the purpose of bacterial detection. Besides intact phage particles, phage-derived affinity molecules such as cell wall binding domains and receptor binding proteins can serve for this purpose. This review provides an overview of existing phage-based technologies for detection of foodborne pathogens, and highlights the most recent developments in this field, with particular emphasis on phage-based biosensors. PMID:24533229

  12. Modelling the interaction between bacteriophages and their bacterial hosts.

    Science.gov (United States)

    Beke, Gabor; Stano, Matej; Klucar, Lubos

    2016-09-01

    A mathematical model simulating the interaction between bacteriophages and their bacterial hosts has been developed. It is based on other known models describing this type of interaction, enhanced with an ability to model the system influenced by other environmental factor such as pH and temperature. This could be used for numerous estimations of growth rate, when the pH and/or the temperature of the environment are not constant. The change of pH or the temperature greatly affects the specific growth rate which has an effect on the final results of the simulation. Since the model aims on practical application and easy accessibility, an interactive website has been developed where users can run simulations with their own parameters and easily calculate and visualise the result of simulation. The web simulation is accessible at the URL http://www.phisite.org/model. PMID:27393678

  13. Biodiversity of Lactobacillus helveticus bacteriophages isolated from cheese whey starters.

    Science.gov (United States)

    Zago, Miriam; Bonvini, Barbara; Rossetti, Lia; Meucci, Aurora; Giraffa, Giorgio; Carminati, Domenico

    2015-05-01

    Twenty-one Lactobacillus helveticus bacteriophages, 18 isolated from different cheese whey starters and three from CNRZ collection, were phenotypically and genetically characterised. A biodiversity between phages was evidenced both by host range and molecular (RAPD-PCR) typing. A more detailed characterisation of six phages showed similar structural protein profiles and a relevant genetic biodiversity, as shown by restriction enzyme analysis of total DNA. Latent period, burst time and burst size data evidenced that phages were active and virulent. Overall, data highlighted the biodiversity of Lb. helveticus phages isolated from cheese whey starters, which were confirmed to be one of the most common phage contamination source in dairy factories. More research is required to further unravel the ecological role of Lb. helveticus phages and to evaluate their impact on the dairy fermentation processes where whey starter cultures are used.

  14. Role of osmotic and hydrostatic pressures in bacteriophage genome ejection

    Science.gov (United States)

    Lemay, Serge G.; Panja, Debabrata; Molineux, Ian J.

    2013-02-01

    A critical step in the bacteriophage life cycle is genome ejection into host bacteria. The ejection process for double-stranded DNA phages has been studied thoroughly in vitro, where after triggering with the cellular receptor the genome ejects into a buffer. The experimental data have been interpreted in terms of the decrease in free energy of the densely packed DNA associated with genome ejection. Here we detail a simple model of genome ejection in terms of the hydrostatic and osmotic pressures inside the phage, a bacterium, and a buffer solution or culture medium. We argue that the hydrodynamic flow associated with the water movement from the buffer solution into the phage capsid and further drainage into the bacterial cytoplasm, driven by the osmotic gradient between the bacterial cytoplasm and culture medium, provides an alternative mechanism for phage genome ejection in vivo; the mechanism is perfectly consistent with phage genome ejection in vitro.

  15. Review: elimination of bacteriophages in whey and whey products.

    Science.gov (United States)

    Atamer, Zeynep; Samtlebe, Meike; Neve, Horst; J Heller, Knut; Hinrichs, Joerg

    2013-01-01

    As the cheese market faces strong international competition, the optimization of production processes becomes more important for the economic success of dairy companies. In dairy productions, whey from former cheese batches is frequently re-used to increase the yield, to improve the texture and to increase the nutrient value of the final product. Recycling of whey cream and particulated whey proteins is also routinely performed. Most bacteriophages, however, survive pasteurization and may re-enter the cheese manufacturing process. There is a risk that phages multiply to high numbers during the production. Contamination of whey samples with bacteriophages may cause problems in cheese factories because whey separation often leads to aerosol-borne phages and thus contamination of the factory environment. Furthermore, whey cream or whey proteins used for recycling into cheese matrices may contain thermo-resistant phages. Drained cheese whey can be contaminated with phages as high as 10(9) phages mL(-1). When whey batches are concentrated, phage titers can increase significantly by a factor of 10 hindering a complete elimination of phages. To eliminate the risk of fermentation failure during recycling of whey, whey treatments assuring an efficient reduction of phages are indispensable. This review focuses on inactivation of phages in whey by thermal treatment, ultraviolet (UV) light irradiation, and membrane filtration. Inactivation by heat is the most common procedure. However, application of heat for inactivation of thermo-resistant phages in whey is restricted due to negative effects on the functional properties of native whey proteins. Therefore an alternative strategy applying combined treatments should be favored - rather than heating the dairy product at extreme temperature/time combinations. By using membrane filtration or UV treatment in combination with thermal treatment, phage numbers in whey can be reduced sufficiently to prevent subsequent phage

  16. Review: elimination of bacteriophages in whey and whey products

    Directory of Open Access Journals (Sweden)

    Zeynep eAtamer

    2013-07-01

    Full Text Available As the cheese market faces strong international competition, the optimization of production processes becomes more important for the economic success of dairy companies. In dairy productions, whey from former cheese batches is frequently re-used to increase the yield, to improve the texture and to increase the nutrient value of the final product. Recycling of whey cream and particulated whey proteins is also routinely performed. Most bacteriophages, however, survive pasteurization and may re-enter the cheese manufacturing process. There is a risk that phages multiply to high numbers during the production. Contamination of whey samples with bacteriophages may cause problems in cheese factories because whey separation often leads to aerosol-borne phages and thus contamination of the factory environment. Furthermore, whey cream or whey proteins used for recycling into cheese matrices may contain thermo-resistant phages. Drained cheese whey can be contaminated with phages as high as 109 phages per mL. When whey batches are concentrated, phage titers can increase significantly by a factor of 10 hindering a complete elimination of phages. To eliminate the risk of fermentation failure during recycling of whey, whey treatments assuring an efficient reduction of phages are indispensable. This review focuses on inactivation of phages in whey by thermal treatment, ultraviolet (UV light irradiation and membrane filtration. Inactivation by heat is the most common procedure. However, application of heat for inactivation of thermo-resistant phages in whey is restricted due to negative effects on the functional properties of native whey proteins. Therefore an alternative strategy applying combined treatments should be favoured - rather than heating the dairy product at extreme temperature/time combinations. By using membrane filtration or UV treatment in combination with thermal treatment, phage numbers in whey can be reduced sufficiently to prevent subsequent

  17. Review: elimination of bacteriophages in whey and whey products.

    Science.gov (United States)

    Atamer, Zeynep; Samtlebe, Meike; Neve, Horst; J Heller, Knut; Hinrichs, Joerg

    2013-01-01

    As the cheese market faces strong international competition, the optimization of production processes becomes more important for the economic success of dairy companies. In dairy productions, whey from former cheese batches is frequently re-used to increase the yield, to improve the texture and to increase the nutrient value of the final product. Recycling of whey cream and particulated whey proteins is also routinely performed. Most bacteriophages, however, survive pasteurization and may re-enter the cheese manufacturing process. There is a risk that phages multiply to high numbers during the production. Contamination of whey samples with bacteriophages may cause problems in cheese factories because whey separation often leads to aerosol-borne phages and thus contamination of the factory environment. Furthermore, whey cream or whey proteins used for recycling into cheese matrices may contain thermo-resistant phages. Drained cheese whey can be contaminated with phages as high as 10(9) phages mL(-1). When whey batches are concentrated, phage titers can increase significantly by a factor of 10 hindering a complete elimination of phages. To eliminate the risk of fermentation failure during recycling of whey, whey treatments assuring an efficient reduction of phages are indispensable. This review focuses on inactivation of phages in whey by thermal treatment, ultraviolet (UV) light irradiation, and membrane filtration. Inactivation by heat is the most common procedure. However, application of heat for inactivation of thermo-resistant phages in whey is restricted due to negative effects on the functional properties of native whey proteins. Therefore an alternative strategy applying combined treatments should be favored - rather than heating the dairy product at extreme temperature/time combinations. By using membrane filtration or UV treatment in combination with thermal treatment, phage numbers in whey can be reduced sufficiently to prevent subsequent phage

  18. Alternatives to antibiotics: bacteriocins, antimicrobial peptides and bacteriophages.

    Science.gov (United States)

    Joerger, R D

    2003-04-01

    Bacteriocins, antimicrobial peptides, and bacteriophage have attracted attention as potential substitutes for, or as additions to, currently used antimicrobial compounds. This publication will review research on the potential application of these alternative antimicrobial agents to poultry production and processing. Bacteriocins are proteinaceous compounds of bacterial origin that are lethal to bacteria other than the producing strain. It is assumed that some of the bacteria in the intestinal tract produce bacteriocins as a means to achieve a competitive advantage, and bacteriocin-producing bacteria might be a desirable part of competitive exclusion preparations. Purified or partially purified bacteriocins could be used as preservatives or for the reduction or elimination of certain pathogens. Currently only nisin, produced by certain strains of Lactococcus lactis subsp. lactis, has regulatory approval for use in certain foods, and its use for poultry products has been studied extensively. Exploration of the application of antimicrobial peptides from sources other than bacteria to poultry has not yet commenced to a significant extent. Evidence for the ability of chickens to produce such antimicrobial peptides has been provided, and it is likely that these peptides play an important role in the defense against various pathogens. Bacteriophages have received renewed attention as possible agents against infecting bacteria. Evidence from several trials indicates that phage therapy can be effective under certain circumstances. Numerous obstacles for the use of phage as antimicrobials for poultry or poultry products remain. Chiefly among them are the narrow host range of many phages, the issue of phage resistance, and the possibility of phage-mediated transfer of genetic material to bacterial hosts. Regulatory issues and the high cost of producing such alternative antimicrobial agents are also factors that might prevent application of these agents in the near future

  19. Bacteriophage-encoded shiga toxin gene in atypical bacterial host

    Directory of Open Access Journals (Sweden)

    Casas Veronica

    2011-07-01

    Full Text Available Abstract Background Contamination from fecal bacteria in recreational waters is a major health concern since bacteria capable of causing human disease can be found in animal feces. The Dog Beach area of Ocean Beach in San Diego, California is a beach prone to closures due to high levels of fecal indicator bacteria (FIB. A potential source of these FIB could be the canine feces left behind by owners who do not clean up after their pets. We tested this hypothesis by screening the DNA isolated from canine feces for the bacteriophage-encoded stx gene normally found in the virulent strains of the fecal bacterium Escherichia coli. Results Twenty canine fecal samples were collected, processed for total and bacterial fraction DNA, and screened by PCR for the stx gene. The stx gene was detected in the total and bacterial fraction DNA of one fecal sample. Bacterial isolates were then cultivated from the stx-positive fecal sample. Eighty nine of these canine fecal bacterial isolates were screened by PCR for the stx gene. The stx gene was detected in five of these isolates. Sequencing and phylogenetic analyses of 16S rRNA gene PCR products from the canine fecal bacterial isolates indicated that they were Enterococcus and not E. coli. Conclusions The bacteriophage-encoded stx gene was found in multiple species of bacteria cultivated from canine fecal samples gathered at the shoreline of the Dog Beach area of Ocean Beach in San Diego, California. The canine fecal bacteria carrying the stx gene were not the typical E. coli host and were instead identified through phylogenetic analyses as Enterococcus. This suggests a large degree of horizontal gene transfer of exotoxin genes in recreational waters.

  20. Sewage bacteriophage inactivation by cationic porphyrins: influence of light parameters.

    Science.gov (United States)

    Costa, Liliana; Carvalho, Carla M B; Faustino, Maria A F; Neves, Maria G P M S; Tomé, João P C; Tomé, Augusto C; Cavaleiro, José A S; Cunha, Angela; Almeida, Adelaide

    2010-08-01

    Photodynamic therapy has been used to inactivate microorganisms through the use of targeted photosensitizers. Although the photoinactivation of microorganisms has already been studied under different conditions, a systematic evaluation of irradiation characteristics is still limited. The goal of this study was to test how the light dose, fluence rate and irradiation source affect the viral photoinactivation of a T4-like sewage bacteriophage. The experiments were carried out using white PAR light delivered by fluorescent PAR lamps (40 W m(-2)), sun light (600 W m(-2)) and an halogen lamp (40-1690 W m(-2)). Phage suspensions and two cationic photosensitizers (Tetra-Py(+)-Me, Tri-Py(+)-Me-PF) at concentrations of 0.5, 1.0 and 5.0 microM were used. The results showed that the efficacy of the bacteriophage photoinactivation is correlated not only with the sensitizer and its concentration but also with the light source, energy dose and fluence rate applied. Both photosensitizers at 5.0 microM were able to inactivate the T4-like phage to the limit of detection for each light source and fluence rate. However, depending of the light parameters, different irradiation times are required. The efficiency of photoinactivation is dependent on the spectral emission distribution of the light sources used. Considering the same light source and a fixed light dose applied at different fluence rates, phage inactivation was significantly higher when low fluence rates were used. In this way, the light source, fluence rate and total light dose play an important role in the effectiveness of the antimicrobial photodynamic therapy and should always be considered when establishing an optimal antimicrobial protocol. PMID:20563346

  1. Bacteriophage functional genomics and its role in bacterial pathogen detection.

    Science.gov (United States)

    Klumpp, Jochen; Fouts, Derrick E; Sozhamannan, Shanmuga

    2013-07-01

    Emerging and reemerging bacterial infectious diseases are a major public health concern worldwide. The role of bacteriophages in the emergence of novel bacterial pathogens by horizontal gene transfer was highlighted by the May 2011 Escherichia coli O104:H4 outbreaks that originated in Germany and spread to other European countries. This outbreak also highlighted the pivotal role played by recent advances in functional genomics in rapidly deciphering the virulence mechanism elicited by this novel pathogen and developing rapid diagnostics and therapeutics. However, despite a steady increase in the number of phage sequences in the public databases, boosted by the next-generation sequencing technologies, few functional genomics studies of bacteriophages have been conducted. Our definition of 'functional genomics' encompasses a range of aspects: phage genome sequencing, annotation and ascribing functions to phage genes, prophage identification in bacterial sequences, elucidating the events in various stages of phage life cycle using genomic, transcriptomic and proteomic approaches, defining the mechanisms of host takeover including specific bacterial-phage protein interactions and identifying virulence and other adaptive features encoded by phages and finally, using prophage genomic information for bacterial detection/diagnostics. Given the breadth and depth of this definition and the fact that some of these aspects (especially phage-encoded virulence/adaptive features) have been treated extensively in other reviews, we restrict our focus only on certain aspects. These include phage genome sequencing and annotation, identification of prophages in bacterial sequences and genetic characterization of phages, functional genomics of the infection process and finally, bacterial identification using genomic information.

  2. Bacteriophage functional genomics and its role in bacterial pathogen detection.

    Science.gov (United States)

    Klumpp, Jochen; Fouts, Derrick E; Sozhamannan, Shanmuga

    2013-07-01

    Emerging and reemerging bacterial infectious diseases are a major public health concern worldwide. The role of bacteriophages in the emergence of novel bacterial pathogens by horizontal gene transfer was highlighted by the May 2011 Escherichia coli O104:H4 outbreaks that originated in Germany and spread to other European countries. This outbreak also highlighted the pivotal role played by recent advances in functional genomics in rapidly deciphering the virulence mechanism elicited by this novel pathogen and developing rapid diagnostics and therapeutics. However, despite a steady increase in the number of phage sequences in the public databases, boosted by the next-generation sequencing technologies, few functional genomics studies of bacteriophages have been conducted. Our definition of 'functional genomics' encompasses a range of aspects: phage genome sequencing, annotation and ascribing functions to phage genes, prophage identification in bacterial sequences, elucidating the events in various stages of phage life cycle using genomic, transcriptomic and proteomic approaches, defining the mechanisms of host takeover including specific bacterial-phage protein interactions and identifying virulence and other adaptive features encoded by phages and finally, using prophage genomic information for bacterial detection/diagnostics. Given the breadth and depth of this definition and the fact that some of these aspects (especially phage-encoded virulence/adaptive features) have been treated extensively in other reviews, we restrict our focus only on certain aspects. These include phage genome sequencing and annotation, identification of prophages in bacterial sequences and genetic characterization of phages, functional genomics of the infection process and finally, bacterial identification using genomic information. PMID:23520178

  3. Bacteriophage and their potential roles in the human oral cavity

    Science.gov (United States)

    Edlund, Anna; Santiago-Rodriguez, Tasha M.; Boehm, Tobias K.; Pride, David T.

    2015-01-01

    The human oral cavity provides the perfect portal of entry for viruses and bacteria in the environment to access new hosts. Hence, the oral cavity is one of the most densely populated habitats of the human body containing some 6 billion bacteria and potentially 35 times that many viruses. The role of these viral communities remains unclear; however, many are bacteriophage that may have active roles in shaping the ecology of oral bacterial communities. Other implications for the presence of such vast oral phage communities include accelerating the molecular diversity of their bacterial hosts as both host and phage mutate to gain evolutionary advantages. Additional roles include the acquisitions of new gene functions through lysogenic conversions that may provide selective advantages to host bacteria in response to antibiotics or other types of disturbances, and protection of the human host from invading pathogens by binding to and preventing pathogens from crossing oral mucosal barriers. Recent evidence suggests that phage may be more involved in periodontal diseases than were previously thought, as their compositions in the subgingival crevice in moderate to severe periodontitis are known to be significantly altered. However, it is unclear to what extent they contribute to dysbiosis or the transition of the microbial community into a state promoting oral disease. Bacteriophage communities are distinct in saliva compared to sub- and supragingival areas, suggesting that different oral biogeographic niches have unique phage ecology shaping their bacterial biota. In this review, we summarize what is known about phage communities in the oral cavity, the possible contributions of phage in shaping oral bacterial ecology, and the risks to public health oral phage may pose through their potential to spread antibiotic resistance gene functions to close contacts. PMID:25861745

  4. Bacteriophage and their potential roles in the human oral cavity.

    Science.gov (United States)

    Edlund, Anna; Santiago-Rodriguez, Tasha M; Boehm, Tobias K; Pride, David T

    2015-01-01

    The human oral cavity provides the perfect portal of entry for viruses and bacteria in the environment to access new hosts. Hence, the oral cavity is one of the most densely populated habitats of the human body containing some 6 billion bacteria and potentially 35 times that many viruses. The role of these viral communities remains unclear; however, many are bacteriophage that may have active roles in shaping the ecology of oral bacterial communities. Other implications for the presence of such vast oral phage communities include accelerating the molecular diversity of their bacterial hosts as both host and phage mutate to gain evolutionary advantages. Additional roles include the acquisitions of new gene functions through lysogenic conversions that may provide selective advantages to host bacteria in response to antibiotics or other types of disturbances, and protection of the human host from invading pathogens by binding to and preventing pathogens from crossing oral mucosal barriers. Recent evidence suggests that phage may be more involved in periodontal diseases than were previously thought, as their compositions in the subgingival crevice in moderate to severe periodontitis are known to be significantly altered. However, it is unclear to what extent they contribute to dysbiosis or the transition of the microbial community into a state promoting oral disease. Bacteriophage communities are distinct in saliva compared to sub- and supragingival areas, suggesting that different oral biogeographic niches have unique phage ecology shaping their bacterial biota. In this review, we summarize what is known about phage communities in the oral cavity, the possible contributions of phage in shaping oral bacterial ecology, and the risks to public health oral phage may pose through their potential to spread antibiotic resistance gene functions to close contacts. PMID:25861745

  5. Bacteriophage and their potential roles in the human oral cavity

    Directory of Open Access Journals (Sweden)

    Anna Edlund

    2015-04-01

    Full Text Available The human oral cavity provides the perfect portal of entry for viruses and bacteria in the environment to access new hosts. Hence, the oral cavity is one of the most densely populated habitats of the human body containing some 6 billion bacteria and potentially 35 times that many viruses. The role of these viral communities remains unclear; however, many are bacteriophage that may have active roles in shaping the ecology of oral bacterial communities. Other implications for the presence of such vast oral phage communities include accelerating the molecular diversity of their bacterial hosts as both host and phage mutate to gain evolutionary advantages. Additional roles include the acquisitions of new gene functions through lysogenic conversions that may provide selective advantages to host bacteria in response to antibiotics or other types of disturbances, and protection of the human host from invading pathogens by binding to and preventing pathogens from crossing oral mucosal barriers. Recent evidence suggests that phage may be more involved in periodontal diseases than were previously thought, as their compositions in the subgingival crevice in moderate to severe periodontitis are known to be significantly altered. However, it is unclear to what extent they contribute to dysbiosis or the transition of the microbial community into a state promoting oral disease. Bacteriophage communities are distinct in saliva compared to sub- and supragingival areas, suggesting that different oral biogeographic niches have unique phage ecology shaping their bacterial biota. In this review, we summarize what is known about phage communities in the oral cavity, the possible contributions of phage in shaping oral bacterial ecology, and the risks to public health oral phage may pose through their potential to spread antibiotic resistance gene functions to close contacts.

  6. Pb-Pb age and Rb-Sr and Sm-Nd isotope signature of paleoproterozoic syenitic plutonism in the south of Salvador-Curaca mobile belt: Sao Felix Syenitic Massif, Bahia-Brazil

    International Nuclear Information System (INIS)

    The Sao Felix Syenitic Massif (MSSF) has a tabular shape with about 32 km2 that represents the south expression of the aligned syenitic plutonism, which occur in the middle part of Salvador-Curaca mobile belt (CMSC). Single zircon dating by stepwise Pb evaporation methodology yields an age of 2098 ± 1 Ma to SFSM. This data correlate the emplacement of the SFSM with the late stages of SCMB stabilization. This massif is isotopically characterized by negative epsilon neodymium values (-1.45 to -2.89) and low initial strontium ratio (0.701 to 0.704). SFSM isotopic signature is similar to the ones displayed by the others syenites from the belt and reflects an enriched source which should be related to a metasomatic enriched mantle. (author)

  7. Examining Prebiotic Chemistry Using O(^1D) Insertion Reactions

    Science.gov (United States)

    Hays, Brian M.; Laas, Jacob C.; Weaver, Susanna L. Widicus

    2013-06-01

    Aminomethanol, methanediol, and methoxymethanol are all prebiotic molecules expected to form via photo-driven grain surface chemistry in the interstellar medium (ISM). These molecules are expected to be precursors for larger, biologically-relevant molecules in the ISM such as sugars and amino acids. These three molecules have not yet been detected in the ISM because of the lack of available rotational spectra. A high resolution (sub)millimeter spectrometer coupled to a molecular source is being used to study these molecules using O(^1D) insertion reactions. The O(^1D) chemistry is initiated using an excimer laser, and the products of the insertion reactions are adiabatically cooled using a supersonic expansion. Experimental parameters are being optimized by examination of methanol formed from O(^1D) insertion into methane. Theoretical studies of the structure and reaction energies for aminomethanol, methanediol, and methoxymethanol have been conducted to guide the laboratory studies once the methanol experiment has been optimized. The results of the calculations and initial experimental results will be presented.

  8. Isolation and Characterization of Lytic Properties of Bacteriophages Specific for M. haemolytica Strains.

    Directory of Open Access Journals (Sweden)

    Renata Urban-Chmiel

    Full Text Available The objective of this study was isolation and morphological characterization of temperate bacteriophages obtained from M. haemolytica strains and evaluation of their lytic properties in vitro against M. haemolytica isolated from the respiratory tract of calves.The material for the study consisted of the reference strain M. haemolytica serotype 1 (ATCC® BAA-410™, reference serotypes A1, A2, A5, A6, A7, A9 and A11, and wild-type isolates of M. haemolytica. Bacteriophages were induced from an overnight bacterial starter culture of all examined M. haemolytica strains treated with mitomycin C. The lytic properties and host ranges were determined by plaque assays. The morphology of the bacteriophages was examined in negative-stained smears with 5% uranyl acetate solution using a transmission electron microscope. The genetic analysis of the bacteriophages was followed by restriction analysis of bacteriophage DNA. This was followed by analysis of genetic material by polymerase chain reaction (PCR.Eight bacteriophages were obtained, like typical of the families Myoviridae, Siphoviridae and Podoviridae. Most of the bacteriophages exhibited lytic properties against the M. haemolytica strains. Restriction analysis revealed similarities to the P2-like phage obtained from the strain M. haemolytica BAA-410. The most similar profiles were observed in the case of bacteriophages φA1 and φA5. All of the bacteriophages obtained were characterized by the presence of additional fragments in the restriction profiles with respect to the P2-like reference phage. In the analysis of PCR products for the P2-like reference phage phi-MhaA1-PHL101 (DQ426904 and the phages of the M. haemolytica serotypes, a 734-bp phage PCR product was obtained. The primers were programmed in Primer-Blast software using the structure of the sequence DQ426904 of reference phage PHL101.The results obtained indicate the need for further research aimed at isolating and characterizing

  9. The Effectiveness of Bacteriophages against Methicillin-Resistant Staphylococcus aureus ST398 Nasal Colonization in Pigs

    Science.gov (United States)

    Duim, Birgitta; Fluit, Ad C; Carney, Jennifer; van Nes, Arie; Wagenaar, Jaap A

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important colonizer in animals and an opportunistic pathogen in humans. In humans, MRSA can cause infections that might be difficult to treat because of antimicrobial resistance. The use of bacteriophages has been suggested as a potential approach for the control of MRSA colonization to minimize the—often occupational—exposure of humans. The aim of this study was to assess the efficacy of bacteriophage treatment on porcine nasal colonization with MRSA in vitro, in vivo, and ex vivo. The effectiveness of a bacteriophage combination of phage K*710 and P68 was assessed in vitro by incubating them with MRSA V0608892/1 (ST398) measuring the OD600 hourly. To study the in vivo effect, bacteriophages were administered in a gel developed for human application, which contain 109 plaque-forming units (pfu)/mL (K and P68 in a 19.25:1 ratio) for 5 days to piglets (N = 8) that were experimentally colonized with the MRSA strain. Eight piglets experimentally colonized were used as a negative control. The MRSA strain was also used to colonize porcine nasal mucosa explants and bacteriophages were applied to assess the ex vivo efficacy of treatment. Bacteriophages were effective in vitro. In vivo, sixteen piglets were colonized with MRSA but the number of CFU recovered after the application of the bacteriophages in 8 piglets was not reduced compared to the control animals (approx. 105 CFU/swab). In the ex vivo model, 108 CFU were used to establish colonization with MRSA; a reduction of colonization was not observed after application of bacteriophages. However, application of mupirocin both in vivo and ex vivo resulted in a near eradication of MRSA. In conclusion: i) The MRSA strain was killed in the presence of the bacteriophages phage K*710 and P68 in vitro. ii) Bacteriophages did not reduce porcine nasal colonization in vivo or ex vivo. Physiological in vivo and ex vivo conditions may explain these observations. Efficacy

  10. Properties of the ribonucleic acid bacteriophage ZIK-1 coat protein and its synthesis in an Escherichia coli cell-free system.

    Science.gov (United States)

    Robinson, J W

    1972-07-01

    The coat protein subunit of the RNA bacteriophage ZIK/1 has a molecular weight of 12100 and does not contain histidine, methionine and cysteine. The amino acid composition of the coat protein is different from that of other RNA bacteriophage coat proteins. Bacteriophage ZIK/1 belongs to a class of RNA bacteriophages distinct from the f2 type, which lack histidine in their coat proteins, and the Qbeta type, which lack histidine and methionine. Bacteriophage ZIK/1 RNA is an efficient template in the Escherichia coli cell-free system producing coat protein as the major product and a number of non-coat proteins. This result is similar to that obtained with RNA from f2-type bacteriophages. It is probable that the genomes of RNA bacteriophages are structurally similar and that differences between the types of RNA bacteriophage arise from minor differences in RNA sequence.

  11. Climatology of the O(1S) and O(1D) emission rates from WINDII/UARS global measurements

    Science.gov (United States)

    Zhang, Z.; Shepherd, S.

    The Wind Imaging Interferometer WINDII on the Upper Atmospheric Research Satellite UARS has provided a large number of O 1S green line 557 7 nm and O 1D red line 630 0 nm emission rate profiles during 1991-1997 of unprecedented high quality The daytime airglow emission is produced mainly by solar energy deposition and vary according to changes of the solar zenith angle and solar irradiance The nighttime airglow emission rates show strong latitudinal and local time dependences Using both daytime and nighttime measurements the directly solar excited daytime emission rates can be removed and the indirectly excited component is revealed This study presents the seasonal and latitudinal variations of the indirect component of the two airglow emission rates which may be due to tides geomagnetic effects and other physical and photochemical processes

  12. Involvement of colicin in the limited protection of the colicin producing cells against bacteriophage.

    Science.gov (United States)

    Lin, Yu-Hui; Liao, Chen-Chung; Liang, Po-Huang; Yuan, Hanna S; Chak, Kin-Fu

    2004-05-21

    The restriction/modification system is considered to be the most common machinery of microorganisms for protection against bacteriophage infection. However, we found that mitomycin C induced Escherichia coli containing ColE7-K317 can confer limited protection against bacteriophage M13K07 and lambda infection. Our study showed that degree of protection is correlated with the expression level of the ColE7 operon, indicating that colicin E7 alone or the colicin E7-immunity protein complex is directly involved in this protection mechanism. It was also noted that the degree of protection is greater against the single-strand DNA bacteriophage M13K07 than the double-strand bacteriophage(lambda). Coincidently, the K(A) value of ColE7-Im either interacting with single-strand DNA (2.94x10(5)M(-1)) or double-strand DNA (1.75x10(5)M(-1)) reveals that the binding affinity of ColE7-Im with ssDNA is 1.68-fold stronger than that of the protein complex interacting with dsDNA. Interaction between colicin and the DNA may play a central role in this limited protection of the colicin-producing cell against bacteriophages. Based on these observations, we suggest that the colicin exporting pathway may interact to some extent with the bacteriophage infection pathway leading to a limited selective advantage for and limited protection of colicin-producing cells against different bacteriophages. PMID:15110756

  13. Diagnostic Immunization with Bacteriophage ΦX 174 in Patients with Common Variable Immunodeficiency/Hypogammaglobulinemia

    Directory of Open Access Journals (Sweden)

    Lauren L Smith

    2014-08-01

    Full Text Available Purpose: Use of the T cell-dependent neoantigen bacteriophage ΦX 174 has been described since the 1960s as a method to assess specific antibody response in patients with primary immunodeficiencies. We reviewed a cohort of patients at Duke University Medical Center (DUMC who received immunization with bacteriophage and report the clinical utility and safety of the immunization, as well as patient characteristics. Methods: A retrospective chart review was performed of all Duke Immunology Clinic patients (pediatric and adult who received immunizations with bacteriophage, from 1976-2012. Subjects were selected for inclusion if their diagnosis at the time of bacteriophage was either presumed or confirmed common variable immunodeficiency (CVID, hypogammaglobulinemia, transient hypogammaglobulinemia, or antibody deficiency unspecified. Follow up post-immunization was also recorded.Results: One hundred twenty-six patients were identified, 36 adult and 90 pediatric patients. Diagnoses prior to bacteriophage were CVID (n=100, hypogammaglobulinemia (n=23, and antibody deficiency (n=3. Post-immunization diagnoses were CVID (n=65, hypogammaglobulinemia (n=19, unknown (n=23, no primary immune deficiency (n=10, and other primary immunodeficiency (n=9. Seventy-five patients had abnormal bacteriophage results, 37 were normal, and 14 were borderline. There were 257 recorded administrations of the immunization. Information was available on adverse reactions for 171 administrations. Fourteen immunizations were associated with minor adverse events. Nineteen patients stopped their immunoglobulin replacement therapy based on reported normal responses to immunization. Conclusions: Bacteriophage ΦX 174 immunization is a safe, well-tolerated, and clinically useful method to assess antibody response in patients with suspected antibody-mediated immunodeficiencies, particularly those who are on immunoglobulin replacement therapy at the time of immunization

  14. Attenuation and colloidal mobilization of bacteriophages in natural sediments under anoxic as compared to oxic conditions.

    Science.gov (United States)

    Klitzke, Sondra; Schroeder, Jendrik; Selinka, Hans-Christoph; Szewzyk, Regine; Chorus, Ingrid

    2015-06-15

    Redox conditions are known to affect the fate of viruses in porous media. Several studies report the relevance of colloid-facilitated virus transport in the subsurface, but detailed studies on the effect of anoxic conditions on virus retention in natural sediments are still missing. Therefore, we investigated the fate of viruses in natural flood plain sediments with different sesquioxide contents under anoxic conditions by considering sorption to the solid phase, sorption to mobilized colloids, and inactivation in the aqueous phase. Batch experiments were conducted under oxic and anoxic conditions at pH values between 5.1 and 7.6, using bacteriophages MS2 and PhiX174 as model viruses. In addition to free and colloid-associated bacteriophages, dissolved and colloidal concentrations of Fe, Al and organic C as well as dissolved Ca were determined. Results showed that regardless of redox conditions, bacteriophages did not adsorb to mobilized colloids, even under favourable charge conditions. Under anoxic conditions, attenuation of bacteriophages was dominated by sorption over inactivation, with MS2 showing a higher degree of sorption than PhiX174. Inactivation in water was low under anoxic conditions for both bacteriophages with about one log10 decrease in concentration during 16 h. Increased Fe/Al concentrations and a low organic carbon content of the sediment led to enhanced bacteriophage removal under anoxic conditions. However, even in the presence of sufficient Fe/A-(hydr)oxides on the solid phase, bacteriophage sorption was low. We presume that organic matter may limit the potential retention of sesquioxides in anoxic sediments and should thus be considered for the risk assessment of virus breakthrough in the subsurface.

  15. Lytic Infection of Lactococcus lactis by Bacteriophages Tuc2009 and c2 Triggers Alternative Transcriptional Host Responses

    NARCIS (Netherlands)

    Ainsworth, S.; Zomer, A.L.; Mahony, J.; Sinderen, D. van

    2013-01-01

    Here we present an entire temporal transcriptional profile of Lactococcus lactis subsp. cremoris UC509.9 undergoing lytic infection with two distinct bacteriophages, Tuc2009 and c2. Furthermore, corresponding high-resolution whole-phage genome tiling arrays of both bacteriophages were performed thro

  16. Biocontrol of Escherichia coli O157:H7 on fresh-cut lettuce and cantaloupe by treatment with bacteriophage

    Science.gov (United States)

    Introduction: Outbreaks of foodborne illness have been associated with the consumption of cantaloupes and fresh-cut lettuce. Bacteriophage mixtures may be effective biocontrol agents to reduce E. coli O157:H7 on produce. Purpose: The effectiveness of a mixture of bacteriophages (ECP-100) in reducin...

  17. Occurrence of bacteriophages infecting Aeromonas, Enterobacter, and Klebsiella in water and association with contamination sources in Thailand.

    Science.gov (United States)

    Wangkahad, Bencharong; Bosup, Suchada; Mongkolsuk, Skorn; Sirikanchana, Kwanrawee

    2015-06-01

    The co-residence of bacteriophages and their bacterial hosts in humans, animals, and environmental sources directed the use of bacteriophages to track the origins of the pathogenic bacteria that can be found in contaminated water. The objective of this study was to enumerate bacteriophages of Aeromonas caviae (AecaKS148), Enterobacter sp. (EnspKS513), and Klebsiella pneumoniae (KlpnKS648) in water and evaluate their association with contamination sources (human vs. animals). Bacterial host strains were isolated from untreated wastewater in Bangkok, Thailand. A double-layer agar technique was used to detect bacteriophages. All three bacteriophages were detected in polluted canal samples, with likely contamination from human wastewater, whereas none was found in non-polluted river samples. AecaKS148 was found to be associated with human fecal sources, while EnspKS513 and KlpnKS648 seemed to be equally prevalent in both human and animal fecal sources. Both bacteriophages were also present in polluted canals that could receive contamination from other fecal sources or the environment. In conclusion, all three bacteriophages were successfully monitored in Bangkok, Thailand. This study provided an example of bacteriophages for potential use as source identifiers of pathogen contamination. The results from this study will assist in controlling sources of pathogen contamination, especially in developing countries.

  18. Bacteriophage immobilized graphene electrodes for impedimetric sensing of bacteria (Staphylococcus arlettae).

    Science.gov (United States)

    Bhardwaj, Neha; Bhardwaj, Sanjeev K; Mehta, Jyotsana; Mohanta, Girish C; Deep, Akash

    2016-07-15

    Bacteriophages are a class of viruses that specifically infect and replicate within a bacterium. They possess inherent affinity and specificity to the particular bacterial cells. This property of bacteriophages makes them an attractive biorecognition element in the field of biosensor development. In this work, we report the use of an immobilized bacteriophage for the development of a highly sensitive electrochemical sensor for Staphylococcus arlettae, bacteria from the pathogenic family of coagulase-negative staphylococci (CNS). The specific bacteriophages were covalently immobilized on the screen-printed graphene electrodes. Thus, the fabricated bacteriophage biosensor displayed quantitative response for the target bacteria (S. arlettae) for a broad detection range (2.0-2.0 × 10(6) cfu). A fast response time (2 min), low limit of detection (2 cfu), specificity, and stability over a prolonged period (3 months) are some of the important highlights of the proposed sensor. The practical utility of the developed sensor has been demonstrated by the analysis of S. arlettae in spiked water and apple juice samples.

  19. Isolation and characterization of bacteriophages specific to hydrogen-sulfide-producing bacteria.

    Science.gov (United States)

    Gong, Chao; Heringa, Spencer; Singh, Randhir; Kim, Jinkyung; Jiang, Xiuping

    2013-01-01

    The objectives of this study were to isolate and characterize bacteriophages specific to hydrogen-sulfide-producing bacteria (SPB) from raw animal materials, and to develop a SPB-specific bacteriophage cocktail for rendering application. Meat, chicken offal, and feather samples collected from local supermarkets and rendering processing plants were used to isolate SPB (n = 142). Bacteriophages (n = 52) specific to SPB were isolated and purified from the above samples using 18 of those isolated SPB strains as hosts. The host ranges of bacteriophages against 5 selected SPB strains (Escherichia coli, Citrobacter freundii, and Hafnia alvei) were determined. Electron microscopy observation of 9 phages selected for the phage cocktail revealed that 6 phages belonged to the family of Siphoviridae and 3 belonged to the Myoviridae family. Restriction enzyme digestion analysis with endonuclease DraI detected 6 distinguished patterns among the 9 phages. Phage treatment prevented the growth of SPB for up to 10 h with multiplicity of infection ratios of 1, 10, 100, and 1000 in tryptic soy broth at 30 °C, and extended the lag phase of SPB growth for 2 h at 22 °C with multiplicities of infection of 10, 100, and 1000. These results suggest that the selected bacteriophage cocktail has a high potential for phage application to control SPB in raw animal materials destined for the rendering process.

  20. Control of Listeria monocytogenes growth in soft cheeses by bacteriophage P100.

    Science.gov (United States)

    Silva, Elaine Nóbrega Gibson; Figueiredo, Ana Cláudia Leite; Miranda, Fernanda Araújo; de Castro Almeida, Rogeria Comastri

    2014-01-01

    The purpose of this study was to determine the effect of bacteriophage P100 on strains of Listeria monocytogenes in artificially inoculated soft cheeses. A mix of L. monocytogenes 1/2a and Scott A was inoculated in Minas Frescal and Coalho cheeses (approximately 10(5) cfu/g) with the bacteriophage added thereafter (8.3 × 10(7) PFU/g). Samples were analyzed immediately, and then stored at 10 °C for seven days. At time zero, 30 min post-infection, the bacteriophage P100 reduced L. monocytogenes counts by 2.3 log units in Minas Frescal cheese and by 2.1 log units in Coalho cheese, compared to controls without bacteriophage. However, in samples stored under refrigeration for seven days, the bacteriophage P100 was only weakly antilisterial, with the lowest decimal reduction (DR) for the cheeses: 1.0 log unit for Minas Frescal and 0.8 log units for Coalho cheese. The treatment produced a statistically significant decrease in the counts of viable cells (p cycle in the number of viable cells of L. monocytogenes in the samples under refrigeration for seven days. Moreover, a smaller effect of phages was observed. These results, along with other published data, indicate that the effectiveness of the phage treatment depends on the initial concentration of L. monocytogenes, and that a high concentration of phages per unit area is required to ensure sustained inactivation of target pathogens on food surfaces. PMID:24948908

  1. Genetically engineered bacteriophage delivers a tumor necrosis factor alpha antagonist coating on neural electrodes

    International Nuclear Information System (INIS)

    This paper reports a novel approach for the formation of anti-inflammatory surface coating on a neural electrode. The surface coating is realized using a recombinant f88 filamentous bacteriophage, which displays a short platinum binding motif and a tumor necrosis factor alpha antagonist (TNF-α antagonist) on p3 and p8 proteins, respectively. The recombinant bacteriophages are immobilized on the platinum surface by a simple dip coating process. The selective and stable immobilization of bacteriophages on a platinum electrode is confirmed by quartz crystal microbalance with dissipation monitoring, atomic force microscope and fluorescence microscope. From the in vitro cell viability test, the inflammatory cytokine (TNF-α) induced cell death was prevented by presenting recombinant bacteriophage coating, albeit with no significant cytotoxic effect. It is also observed that the bacteriophage coating does not have critical effects on the electrochemical properties such as impedance and charge storage capacities. Thus, this approach demonstrates a promising anti-apoptotic as well as anti-inflammatory surface coating for neural implant applications. (paper)

  2. Proteins responsible for lysogeny of deep-sea thermophilic bacteriophage GVE2 at high temperature.

    Science.gov (United States)

    Song, Qing; Ye, Ting; Zhang, Xiaobo

    2011-06-15

    The lytic and lysogenic life cycle switch of bacteriophages plays very important roles in virus-host interactions. However, the lysogeny of thermophilic bacteriophage infecting thermophile at high temperatures has not been addressed. In this study, two lysogeny-related genes encoding the CI protein and recombinase of GVE2, a thermophilic bacteriophage obtained from a deep-sea hydrothermal vent, were characterized. Temporal analyses showed that the two genes were expressed at early stages of GVE2 infection. Based on chromatin immunoprecipitation (ChIP) assay and electrophoretic mobility shift assay (EMSA), the GVE2 CI protein was bound with only one DNA fragment located at 24264-24036 bp in the GVE2 genome. This location might be the original transcription site and the lysis-lysogeny switch site, which was very different from mesophilic bacteriophages. The GVE2 CI and recombinase proteins could function only at high temperatures. Therefore our study improved our understanding of the lysogeny process of bacteriophages at high temperatures. PMID:21303688

  3. Rapid and Accurate Detection of Bacteriophage Activity against Escherichia coli O157:H7 by Propidium Monoazide Real-Time PCR

    Directory of Open Access Journals (Sweden)

    Hui Liu

    2014-01-01

    Full Text Available Conventional methods to determine the efficacy of bacteriophage (phage for biocontrol of E. coli require several days, due to the need to culture bacteria. Furthermore, cell surface-attached phage particles may lyse bacterial cells during experiments, leading to an overestimation of phage activity. DNA-based real-time quantitative polymerase chain reaction (qPCR is a fast, sensitive, and highly specific means of enumerating pathogens. However, qPCR may underestimate phage activity due to its inability to distinguish viable from nonviable cells. In this study, we evaluated the suitability of propidium monoazide (PMA, a microbial membrane-impermeable dye that inhibits amplification of extracellular DNA and DNA within dead or membrane-compromised cells as a means of using qPCR to identify only intact E. coli cells that survive phage exposure. Escherichia coli O157:H7 strain R508N and 4 phages (T5-like, T1-like, T4-like, and O1-like were studied. Results compared PMA-qPCR and direct plating and confirmed that PMA could successfully inhibit amplification of DNA from compromised/damaged cells E. coli O157:H7. Compared to PMA-qPCR, direct plating overestimated (P < 0.01 phage efficacy as cell surface-attached phage particles lysed E. coli O157:H7 during the plating process. Treatment of samples with PMA in combination with qPCR can therefore be considered beneficial when assessing the efficacy of bacteriophage for biocontrol of E. coli O157:H7.

  4. Biophysics and bioinformatics of transcription regulation in bacteria and bacteriophages

    Science.gov (United States)

    Djordjevic, Marko

    2005-11-01

    Due to rapid accumulation of biological data, bioinformatics has become a very important branch of biological research. In this thesis, we develop novel bioinformatic approaches and aid design of biological experiments by using ideas and methods from statistical physics. Identification of transcription factor binding sites within the regulatory segments of genomic DNA is an important step towards understanding of the regulatory circuits that control expression of genes. We propose a novel, biophysics based algorithm, for the supervised detection of transcription factor (TF) binding sites. The method classifies potential binding sites by explicitly estimating the sequence-specific binding energy and the chemical potential of a given TF. In contrast with the widely used information theory based weight matrix method, our approach correctly incorporates saturation in the transcription factor/DNA binding probability. This results in a significant reduction in the number of expected false positives, and in the explicit appearance---and determination---of a binding threshold. The new method was used to identify likely genomic binding sites for the Escherichia coli TFs, and to examine the relationship between TF binding specificity and degree of pleiotropy (number of regulatory targets). We next address how parameters of protein-DNA interactions can be obtained from data on protein binding to random oligos under controlled conditions (SELEX experiment data). We show that 'robust' generation of an appropriate data set is achieved by a suitable modification of the standard SELEX procedure, and propose a novel bioinformatic algorithm for analysis of such data. Finally, we use quantitative data analysis, bioinformatic methods and kinetic modeling to analyze gene expression strategies of bacterial viruses. We study bacteriophage Xp10 that infects rice pathogen Xanthomonas oryzae. Xp10 is an unusual bacteriophage, which has morphology and genome organization that most closely

  5. Comparison of five bacteriophages as models for viral aerosol studies.

    Science.gov (United States)

    Turgeon, Nathalie; Toulouse, Marie-Josée; Martel, Bruno; Moineau, Sylvain; Duchaine, Caroline

    2014-07-01

    Bacteriophages are perceived to be good models for the study of airborne viruses because they are safe to use, some of them display structural features similar to those of human and animal viruses, and they are relatively easy to produce in large quantities. Yet, only a few studies have investigated them as models. It has previously been demonstrated that aerosolization, environmental conditions, and sampling conditions affect viral infectivity, but viral infectivity is virus dependent. Thus, several virus models are likely needed to study their general behavior in aerosols. The aim of this study was to compare the effects of aerosolization and sampling on the infectivity of five tail-less bacteriophages and two pathogenic viruses: MS2 (a single-stranded RNA [ssRNA] phage of the Leviviridae family), Φ6 (a segmented double-stranded RNA [dsRNA] phage of the Cystoviridae family), ΦX174 (a single-stranded DNA [ssDNA] phage of the Microviridae family), PM2 (a double-stranded DNA [dsDNA] phage of the Corticoviridae family), PR772 (a dsDNA phage of the Tectiviridae family), human influenza A virus H1N1 (an ssRNA virus of the Orthomyxoviridae family), and the poultry virus Newcastle disease virus (NDV; an ssRNA virus of the Paramyxoviridae family). Three nebulizers and two nebulization salt buffers (with or without organic fluid) were tested, as were two aerosol sampling devices, a liquid cyclone (SKC BioSampler) and a dry cyclone (National Institute for Occupational Safety and Health two-stage cyclone bioaerosol sampler). The presence of viruses in collected air samples was detected by culture and quantitative PCR (qPCR). Our results showed that these selected five phages behave differently when aerosolized and sampled. RNA phage MS2 and ssDNA phage ΦX174 were the most resistant to aerosolization and sampling. The presence of organic fluid in the nebulization buffer protected phages PR772 and Φ6 throughout the aerosolization and sampling with dry cyclones. In this

  6. Immersion vaccination against Yersinia ruckeri O1, biotype 2 confers cross protection against Y. ruckeri O1 biotype 1

    DEFF Research Database (Denmark)

    Raida, Martin Kristian; Neumann, Lukas; Kragelund Strøm, Helene;

    organs (head kidney, spleen, liver, brain, muscle, heart, intestine, skin and gill). Seven days post infection 40% of mock-vaccinated fish were still heavy infected, which corresponds well with overall mortality in this group (35%). In general pro-inflammatory cytokine expression was higher in the mock......A new biotype 2 of Y. ruckeri O1, which lacks motility has proven highly virulent for rainbow trout, and is causing disease in cultured trout even in fish vaccinated with commercial ERM biotype 1 vaccines. Not much is known about immunity against biotype 2, and therefore have we produced a Y...

  7. Factors influencing lysis time stochasticity in bacteriophage λ

    Directory of Open Access Journals (Sweden)

    Dennehy John J

    2011-08-01

    Full Text Available Abstract Background Despite identical genotypes and seemingly uniform environments, stochastic gene expression and other dynamic intracellular processes can produce considerable phenotypic diversity within clonal microbes. One trait that provides a good model to explore the molecular basis of stochastic variation is the timing of host lysis by bacteriophage (phage. Results Individual lysis events of thermally-inducible λ lysogens were observed using a temperature-controlled perfusion chamber mounted on an inverted microscope. Both mean lysis time (MLT and its associated standard deviation (SD were estimated. Using the SD as a measure of lysis time stochasticity, we showed that lysogenic cells in controlled environments varied widely in lysis times, and that the level of lysis time stochasticity depended on allelic variation in the holin sequence, late promoter (pR' activity, and host growth rate. In general, the MLT was positively correlated with the SD. Both lower pR' activities and lower host growth rates resulted in larger SDs. Results from premature lysis, induced by adding KCN at different time points after lysogen induction, showed a negative correlation between the timing of KCN addition and lysis time stochasticity. Conclusions Taken together with results published by others, we conclude that a large fraction of λ lysis time stochasticity is the result of random events following the expression and diffusion of the holin protein. Consequently, factors influencing the timing of reaching critical holin concentrations in the cell membrane, such as holin production rate, strongly influence the mean lysis time and the lysis time stochasticity.

  8. Modeling the interactions between pathogenic bacteria, bacteriophage and immune response

    Science.gov (United States)

    Leung, Chung Yin (Joey); Weitz, Joshua S.

    The prevalence of antibiotic-resistant strains of pathogenic bacteria has led to renewed interest in the use of bacteriophage (phage), or virus that infects bacteria, as a therapeutic agent against bacterial infections. However, little is known about the theoretical mechanism by which phage therapy may work. In particular, interactions between the bacteria, the phage and the host immune response crucially influences the outcome of the therapy. Few models of phage therapy have incorporated all these three components, and existing models suffer from unrealistic assumptions such as unbounded growth of the immune response. We propose a model of phage therapy with an emphasis on nonlinear feedback arising from interactions with bacteria and the immune response. Our model shows a synergistic effect between the phage and the immune response which underlies a possible mechanism for phage to catalyze the elimination of bacteria even when neither the immune response nor phage could do so alone. We study the significance of this effect for different parameters of infection and immune response, and discuss its implications for phage therapy.

  9. The allosteric switching mechanism in bacteriophage MS2

    Science.gov (United States)

    Perkett, Matthew R.; Mirijanian, Dina T.; Hagan, Michael F.

    2016-07-01

    We use all-atom simulations to elucidate the mechanisms underlying conformational switching and allostery within the coat protein of the bacteriophage MS2. Assembly of most icosahedral virus capsids requires that the capsid protein adopts different conformations at precise locations within the capsid. It has been shown that a 19 nucleotide stem loop (TR) from the MS2 genome acts as an allosteric effector, guiding conformational switching of the coat protein during capsid assembly. Since the principal conformational changes occur far from the TR binding site, it is important to understand the molecular mechanism underlying this allosteric communication. To this end, we use all-atom simulations with explicit water combined with a path sampling technique to sample the MS2 coat protein conformational transition, in the presence and absence of TR-binding. The calculations find that TR binding strongly alters the transition free energy profile, leading to a switch in the favored conformation. We discuss changes in molecular interactions responsible for this shift. We then identify networks of amino acids with correlated motions to reveal the mechanism by which effects of TR binding span the protein. We find that TR binding strongly affects residues located at the 5-fold and quasi-sixfold interfaces in the assembled capsid, suggesting a mechanism by which the TR binding could direct formation of the native capsid geometry. The analysis predicts amino acids whose substitution by mutagenesis could alter populations of the conformational substates or their transition rates.

  10. Temperature dependent bacteriophages of a tropical bacterial pathogen

    Science.gov (United States)

    Shan, Jinyu; Korbsrisate, Sunee; Withatanung, Patoo; Adler, Natalie Lazar; Clokie, Martha R. J.; Galyov, Edouard E.

    2014-01-01

    There is an increasing awareness of the multiple ways that bacteriophages (phages) influence bacterial evolution, population dynamics, physiology, and pathogenicity. By studying a novel group of phages infecting a soil borne pathogen, we revealed a paradigm shifting observation that the phages switch their lifestyle according to temperature. We sampled soil from an endemic area of the serious tropical pathogen Burkholderia pseudomallei, and established that podoviruses infecting the pathogen are frequently present in soil, and many of them are naturally occurring variants of a common virus type. Experiments on one phage in the related model B. thailandensis demonstrated that temperature defines the outcome of phage-bacteria interactions. At higher temperatures (37°C), the phage predominantly goes through a lytic cycle, but at lower temperatures (25°C), the phage remains temperate. This is the first report of a naturally occurring phage that follows a lytic or temperate lifestyle according to temperature. These observations fundamentally alter the accepted views on the abundance, population biology and virulence of B. pseudomallei. Furthermore, when taken together with previous studies, our findings suggest that the phenomenon of temperature dependency in phages is widespread. Such phages are likely to have a profound effect on bacterial biology, and on our ability to culture and correctly enumerate viable bacteria. PMID:25452746

  11. BENEFICIAL FACE OF BACTERIOPHAGES: APPLICATIONS IN FOOD PROCESSING

    Directory of Open Access Journals (Sweden)

    H. V. Raghu

    2012-06-01

    Full Text Available Foods are processed to make them available at all places; consequently, our awareness regarding hygiene measures in food production has also increased dramatically over the last decades. In many countries cases associated with foodborne infectious are increased. However, available techniques are unable to effectively control the problem. Further, exploring novel methods and technologies for ensuring the safety of food with effective quality control approaches are under research. Phages are the natural enemies of bacteria, and are more specific to host renders them ideal candidates for applications designed to increase food safety during the production process. Scientific findings are available showing the possibility to use as biocontrol agents against various pathogens with out interfering with the natural microflora or the cultures in fermented products. Furthermore, phages or phage derived proteins can also be used to detect the presence of unwanted pathogens in food or the production environments, which allows quick and sp ecific identification of viable cells. Bacteriophages are natural, found in various environments including water; foods etc. and are not found significantly influence the human cells.

  12. Temperature dependent bacteriophages of a tropical bacterial pathogen

    Directory of Open Access Journals (Sweden)

    Martha Rebecca Jane Clokie

    2014-11-01

    Full Text Available There is an increasing awareness of the multiple ways that bacteriophages (phages influence bacterial evolution, population dynamics, physiology and pathogenicity. By studying a novel group of phages infecting a soil borne pathogen, we revealed a paradigm shifting observation that the phages switch their lifestyle according to temperature. We sampled soil from an endemic area of the serious tropical pathogen Burkholderia pseudomallei, and established that podoviruses infecting the pathogen are frequently present in soil, and many of them are naturally occurring variants of a common virus type. Experiments on one phage in the related model Burkholderia thailandensis demonstrated that temperature defines the outcome of phage-bacteria interactions. At higher temperatures (37°C, the phage predominantly goes through a lytic cycle, but at lower temperatures (25°C, the phage remains temperate. This is the first report of a naturally occurring phage that follows a lytic or temperate lifestyle according to temperature. These observations fundamentally alter the accepted views on the abundance, population biology and virulence of B. pseudomallei. Furthermore, when taken together with previous studies, our findings suggest that the phenomenon of temperature dependency in phages is widespread. Such phages are likely to have a profound effect on bacterial life, and on our ability to culture and correctly enumerate viable bacteria.

  13. Bacteriophages and Phage-Derived Proteins – Application Approaches

    Science.gov (United States)

    Drulis-Kawa, Zuzanna; Majkowska-Skrobek, Grazyna; Maciejewska, Barbara

    2015-01-01

    Currently, the bacterial resistance, especially to most commonly used antibiotics has proved to be a severe therapeutic problem. Nosocomial and community-acquired infections are usually caused by multidrug resistant strains. Therefore, we are forced to develop an alternative or supportive treatment for successful cure of life-threatening infections. The idea of using natural bacterial pathogens such as bacteriophages is already well known. Many papers have been published proving the high antibacterial efficacy of lytic phages tested in animal models as well as in the clinic. Researchers have also investigated the application of non-lytic phages and temperate phages, with promising results. Moreover, the development of molecular biology and novel generation methods of sequencing has opened up new possibilities in the design of engineered phages and recombinant phage-derived proteins. Encouraging performances were noted especially for phage enzymes involved in the first step of viral infection responsible for bacterial envelope degradation, named depolymerases. There are at least five major groups of such enzymes – peptidoglycan hydrolases, endosialidases, endorhamnosidases, alginate lyases and hyaluronate lyases – that have application potential. There is also much interest in proteins encoded by lysis cassette genes (holins, endolysins, spanins) responsible for progeny release during the phage lytic cycle. In this review, we discuss several issues of phage and phage-derived protein application approaches in therapy, diagnostics and biotechnology in general. PMID:25666799

  14. Novel N4 Bacteriophages Prevail in the Cold Biosphere

    Science.gov (United States)

    Zhan, Yuanchao; Buchan, Alison

    2015-01-01

    Coliphage N4 is a lytic bacteriophage discovered nearly half a century ago, and it was considered to be a “genetic orphan” until very recently, when several additional N4-like phages were discovered to infect nonenteric bacterial hosts. Interest in this genus of phages is stimulated by their unique genetic features and propagation strategies. To better understand the ecology of N4-like phages, we investigated the diversity and geographic patterns of N4-like phages by examining 56 Chesapeake Bay viral communities, using a PCR-clone library approach targeting a diagnostic N4-like DNA polymerase gene. Many new lineages of N4-like phages were found in the bay, and their genotypes shift from the lower to the upper bay. Interestingly, signature sequences of N4-like phages were recovered only from winter month samples, when water temperatures were below 4°C. An analysis of existing metagenomic libraries from various aquatic environments supports the hypothesis that N4-like phages are most prolific in colder waters. In particular, a high number of N4-like phages were detected in Organic Lake, Antarctica, a cold and hypersaline system. The prevalence of N4-like phages in the cold biosphere suggests these viruses possess yet-to-be-determined mechanisms that facilitate lytic infections under cold conditions. PMID:26025897

  15. Disposable amperometric biosensor based on nanostructured bacteriophages for glucose detection

    Science.gov (United States)

    Kang, Yu Ri; Hwang, Kyung Hoon; Kim, Ju Hwan; Nam, Chang Hoon; Kim, Soo Won

    2010-10-01

    The selection of electrode material profoundly influences biosensor science and engineering, as it heavily influences biosensor sensitivity. Here we propose a novel electrochemical detection method using a working electrode consisting of bio-nanowires from genetically modified filamentous phages and nanoparticles. fd-tet p8MMM filamentous phages displaying a three-methionine (MMM) peptide on the major coat protein pVIII (designated p8MMM phages) were immobilized on the active area of an electrochemical sensor through physical adsorption and chemical bonding. Bio-nanowires composed of p8MMM phages and silver nanoparticles facilitated sensitive, rapid and selective detection of particular molecules. We explored whether the composite electrode with bio-nanowires was an effective platform to detect the glucose oxidase. The current response of the bio-nanowire sensor was high at various glucose concentrations (0.1 µm-0.1 mM). This method provides a considerable advantage to demonstrate analyte detection over low concentration ranges. Especially, phage-enabled bio-nanowires can serve as receptors with high affinity and specificity for the detection of particular biomolecules and provide a convenient platform for designing site-directed multifunctional scaffolds based on bacteriophages and may serve as a simple method for label-free detection.

  16. Nanoscale detection of bacteriophage triggered ion cascade (Invited Paper)

    Science.gov (United States)

    Dobozi-King, Maria; Seo, Sungkyu; Kim, Jong U.; Cheng, Mosong; Kish, Laszlo B.; Young, Ryland

    2005-05-01

    In an era of potential bioterrorism and pandemics of antibiotic-resistant microbes, bacterial contaminations of food and water supplies is a major concern. There is an urgent need for the rapid, inexpensive and specific identification of bacteria under field conditions. Here we describe a method that combines the specificity and avidity of bacteriophages with fluctuation analysis of electrical noise. The method is based on the massive, transitory ion leakage that occurs at the moment of phage DNA injection into the host cell. The ion fluxes require only that the cells be physiologically viable (i.e., have energized membranes) and can occur within seconds after mixing the cells with sufficient concentrations of phage particles. To detect these fluxes, we have constructed a nano-well, a lateral, micron-size capacitor of titanium electrodes with gap size of 150 nm, and used it to measure the electrical field fluctuations in microliter (mm3) samples containing phage and bacteria. In mixtures where the analyte bacteria were sensitive to the phage, large stochastic waves with various time and amplitude scales were observed, with power spectra of approximately 1/f2 shape over at 1 - 10 Hz. Development of this SEPTIC (SEnsing of Phage-Triggered Ion Cascades) technology could provide rapid detection and identification of live, pathogenic bacteria on the scale of minutes, with unparalleled specificity. The method has a potential ultimate sensitivity of 1 bacterium/microliter (1 bacterium/mm3).

  17. Detection and phylogenetic analysis of bacteriophage WO in spiders (Araneae).

    Science.gov (United States)

    Yan, Qian; Qiao, Huping; Gao, Jin; Yun, Yueli; Liu, Fengxiang; Peng, Yu

    2015-11-01

    Phage WO is a bacteriophage found in Wolbachia. Herein, we represent the first phylogenetic study of WOs that infect spiders (Araneae). Seven species of spiders (Araneus alternidens, Nephila clavata, Hylyphantes graminicola, Prosoponoides sinensis, Pholcus crypticolens, Coleosoma octomaculatum, and Nurscia albofasciata) from six families were infected by Wolbachia and WO, followed by comprehensive sequence analysis. Interestingly, WO could be only detected Wolbachia-infected spiders. The relative infection rates of those seven species of spiders were 75, 100, 88.9, 100, 62.5, 72.7, and 100 %, respectively. Our results indicated that both Wolbachia and WO were found in three different body parts of N. clavata, and WO could be passed to the next generation of H. graminicola by vertical transmission. There were three different sequences for WO infected in A. alternidens and two different WO sequences from C. octomaculatum. Only one sequence of WO was found for the other five species of spiders. The discovered sequence of WO ranged from 239 to 311 bp. Phylogenetic tree was generated using maximum likelihood (ML) based on the orf7 gene sequences. According to the phylogenetic tree, WOs in N. clavata and H. graminicola were clustered in the same group. WOs from A. alternidens (WAlt1) and C. octomaculatum (WOct2) were closely related to another clade, whereas WO in P. sinensis was classified as a sole cluster.

  18. Chlamydial bacteriophage: No Role in Acute Coronary Events?

    Directory of Open Access Journals (Sweden)

    David M Patrick

    2005-01-01

    Full Text Available BACKGROUND: A relationship between Chlamydia pneumoniae infection and acute coronary syndromes has not been consistently found in published studies. It has been hypothesized that a bacteriophage-infected subset of C pneumoniae may be uniquely equipped to promote atherosclerosis and acute coronary syndromes through the expression of phage genes. METHODS: The authors performed a pilot case-control study of acute coronary events. Case and control subjects were characterized demographically and according to recognized coronary risk factors. These subjects also provided serum for the detection of antibody to the elementary bodies of C pneumoniae and antibody to the Vp1 protein coded by the phage. Bivariate and multivariate comparisons were performed using statistics appropriate for paired analyses. RESULTS: Antibodies to C pneumoniae, Vp1 protein or both were not associated with acute coronary events by bivariate or multivariate analysis. As expected, case subjects were significantly more likely to have hypertension, hypercholesterolemia or diabetes mellitus. CONCLUSION: The present study adds to a growing body of literature that does not support the hypothesized relationship between C pneumoniae (or a phage-infected subset of C pneumoniae and acute coronary syndromes.

  19. Spontaneous release of bacteriophage particles by Lactobacillus rhamnosus pen.

    Science.gov (United States)

    Jarocki, Piotr; Podleśny, Marcin; Pawelec, Jarosław; Malinowska, Agata; Kowalczyk, Sylwia; Targoński, Zdzisław

    2013-03-01

    The identification of bacteriophage proteins on the surface of Lactobacillus rhamnosus Pen was performed by LC-MS/MS analysis. Among the identified proteins, we found a phage-derived major tail protein, two major head proteins, a portal protein, and a host specificity protein. Electron microscopy of a cell surface extract revealed the presence of phage particles in the analyzed samples. The partial sequence of genes encoding the major tail protein for all tested L. rhamnosus strains was determined with specific primers designed in this study. Next, RT-PCR analysis allowed detection of the expression of the major tail protein gene in L. rhamnosus strain Pen at all stages of bacterial growth. The transcription of genes encoding the major tail protein was also proved for other L. rhamnosus strains used in this study. The present work demonstrates the spontanous release of prophage-encoded particles by a commercial probiotic L. rhamnosus strain, which did not significantly affect the bacterial growth of the analyzed strain.

  20. Novel N4 Bacteriophages Prevail in the Cold Biosphere.

    Science.gov (United States)

    Zhan, Yuanchao; Buchan, Alison; Chen, Feng

    2015-08-01

    Coliphage N4 is a lytic bacteriophage discovered nearly half a century ago, and it was considered to be a "genetic orphan" until very recently, when several additional N4-like phages were discovered to infect nonenteric bacterial hosts. Interest in this genus of phages is stimulated by their unique genetic features and propagation strategies. To better understand the ecology of N4-like phages, we investigated the diversity and geographic patterns of N4-like phages by examining 56 Chesapeake Bay viral communities, using a PCR-clone library approach targeting a diagnostic N4-like DNA polymerase gene. Many new lineages of N4-like phages were found in the bay, and their genotypes shift from the lower to the upper bay. Interestingly, signature sequences of N4-like phages were recovered only from winter month samples, when water temperatures were below 4°C. An analysis of existing metagenomic libraries from various aquatic environments supports the hypothesis that N4-like phages are most prolific in colder waters. In particular, a high number of N4-like phages were detected in Organic Lake, Antarctica, a cold and hypersaline system. The prevalence of N4-like phages in the cold biosphere suggests these viruses possess yet-to-be-determined mechanisms that facilitate lytic infections under cold conditions.

  1. Association of a bacteriophage with meningococcal disease in young adults.

    Directory of Open Access Journals (Sweden)

    Emmanuelle Bille

    Full Text Available Despite being the agent of life-threatening meningitis, Neisseria meningitidis is usually carried asymptomatically in the nasopharynx of humans and only occasionally causes disease. The genetic bases for virulence have not been entirely elucidated and the search for new virulence factors in this species is hampered by the lack of an animal model representative of the human disease. As an alternative strategy we employ a molecular epidemiological approach to establish a statistical association of a candidate virulence gene with disease in the human population. We examine the distribution of a previously-identified genetic element, a temperate bacteriophage, in 1288 meningococci isolated from cases of disease and asymptomatic carriage. The phage was over-represented in disease isolates from young adults indicating that it may contribute to invasive disease in this age group. Further statistical analysis indicated that between 20% and 45% of the pathogenic potential of the five most common disease-causing meningococcal groups was linked to the presence of the phage. In the absence of an animal model of human disease, this molecular epidemiological approach permitted the estimation of the influence of the candidate virulence factor. Such an approach is particularly valuable in the investigation of exclusively human diseases.

  2. A promiscuous DNA packaging machine from bacteriophage T4.

    Science.gov (United States)

    Zhang, Zhihong; Kottadiel, Vishal I; Vafabakhsh, Reza; Dai, Li; Chemla, Yann R; Ha, Taekjip; Rao, Venigalla B

    2011-01-01

    Complex viruses are assembled from simple protein subunits by sequential and irreversible assembly. During genome packaging in bacteriophages, a powerful molecular motor assembles at the special portal vertex of an empty prohead to initiate packaging. The capsid expands after about 10%-25% of the genome is packaged. When the head is full, the motor cuts the concatemeric DNA and dissociates from the head. Conformational changes, particularly in the portal, are thought to drive these sequential transitions. We found that the phage T4 packaging machine is highly promiscuous, translocating DNA into finished phage heads as well as into proheads. Optical tweezers experiments show that single motors can force exogenous DNA into phage heads at the same rate as into proheads. Single molecule fluorescence measurements demonstrate that phage heads undergo repeated initiations, packaging multiple DNA molecules into the same head. These results suggest that the phage DNA packaging machine has unusual conformational plasticity, powering DNA into an apparently passive capsid receptacle, including the highly stable virus shell, until it is full. These features probably led to the evolution of viral genomes that fit capsid volume, a strikingly common phenomenon in double-stranded DNA viruses, and will potentially allow design of a novel class of nanocapsid delivery vehicles. PMID:21358801

  3. A promiscuous DNA packaging machine from bacteriophage T4.

    Directory of Open Access Journals (Sweden)

    Zhihong Zhang

    Full Text Available Complex viruses are assembled from simple protein subunits by sequential and irreversible assembly. During genome packaging in bacteriophages, a powerful molecular motor assembles at the special portal vertex of an empty prohead to initiate packaging. The capsid expands after about 10%-25% of the genome is packaged. When the head is full, the motor cuts the concatemeric DNA and dissociates from the head. Conformational changes, particularly in the portal, are thought to drive these sequential transitions. We found that the phage T4 packaging machine is highly promiscuous, translocating DNA into finished phage heads as well as into proheads. Optical tweezers experiments show that single motors can force exogenous DNA into phage heads at the same rate as into proheads. Single molecule fluorescence measurements demonstrate that phage heads undergo repeated initiations, packaging multiple DNA molecules into the same head. These results suggest that the phage DNA packaging machine has unusual conformational plasticity, powering DNA into an apparently passive capsid receptacle, including the highly stable virus shell, until it is full. These features probably led to the evolution of viral genomes that fit capsid volume, a strikingly common phenomenon in double-stranded DNA viruses, and will potentially allow design of a novel class of nanocapsid delivery vehicles.

  4. Deposition kinetics of MS2 bacteriophages on clay mineral surfaces.

    Science.gov (United States)

    Tong, Meiping; Shen, Yun; Yang, Haiyan; Kim, Hyunjung

    2012-04-01

    The deposition of bacteriophage MS2 on bare and clay-coated silica surfaces was examined in both monovalent (NaCl) and divalent (CaCl(2) and MgCl(2)) solutions under a wide range of environmentally relevant ionic strength and pH conditions by utilizing a quartz crystal microbalance with dissipation (QCM-D). Two types of clay, bentonite and kaolinite, were concerned in this study. To better understand MS2 deposition mechanisms, QCM-D data were complemented by zeta potentials measurements and Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction forces calculation. In both monovalent and divalent solutions, deposition efficiencies of MS2 increased with increasing ionic strength both on bare and clay-coated surfaces, which agreed with the trends of interaction forces between MS2 and solid surface and thus was consistent with DLVO theory. The presence of divalent ions (Ca(2+) and Mg(2+)) in solutions greatly increased virus deposition on both silica and clay deposited surfaces. Coating silica surfaces with clay minerals, either kaolinite or bentonite, could significantly increase MS2 deposition.

  5. Dual Functionalized Bacteriophage Qβ as a Photocaged Drug Carrier.

    Science.gov (United States)

    Chen, Zhuo; Li, Na; Chen, Luxi; Lee, Jiyong; Gassensmith, Jeremiah J

    2016-09-01

    Proteinatious nanoparticles are emerging as promising materials in biomedical research owing to their many unique properties and our interest focuses on integrating environmental responsivity into these systems. In this work, the use of a virus-like particle (VLP) derived from bacteriophage Qβ as a photocaged drug delivery system is investigated. Ideally, a photocaged nanoparticle platform should be harmless and inert without activation by light yet, upon photoirradiation, should cause cell death. Approximately 530 photocleavable doxorubicin complexes are installed initially onto the surface of Qβ by CuAAC reaction for photocaging therapy; however, aggregation and precipitation are found to cause cell death at higher concentrations. In order to improve solution stability, thiol-dibromomaleimide chemistry has been developed to orthogonally modify the VLP. This chemistry provides a robust method of incorporating additional functionality at the disulfides on Qβ, which was used to increase the stability and solubility of the drug-loaded VLPs. As a result, the dual functionalied VLPs with polyethylene glycol and photocaged doxorubicin show not only negligible cytotoxicity before photoactivation but also highly controllable photorelease and cell killing power. PMID:27351167

  6. Bacteriophages with the Ability to Degrade Uropathogenic Escherichia Coli Biofilms

    Directory of Open Access Journals (Sweden)

    Amee Manges

    2012-04-01

    Full Text Available Escherichia coli-associated urinary tract infections (UTIs are among the most common bacterial infections in humans. UTIs are usually managed with antibiotic therapy, but over the years, antibiotic-resistant strains of uropathogenic E. coli (UPEC have emerged. The formation of biofilms further complicates the treatment of these infections by making them resistant to killing by the host immune system as well as by antibiotics. This has encouraged research into therapy using bacteriophages (phages as a supplement or substitute for antibiotics. In this study we characterized 253 UPEC in terms of their biofilm-forming capabilities, serotype, and antimicrobial resistance. Three phages were then isolated (vB_EcoP_ACG-C91, vB_EcoM_ACG-C40 and vB_EcoS_ACG-M12 which were able to lyse 80.5% of a subset (42 of the UPEC strains able to form biofilms. Correlation was established between phage sensitivity and specific serotypes of the UPEC strains. The phages’ genome sequences were determined and resulted in classification of vB_EcoP_ACG-C91 as a SP6likevirus, vB_EcoM_ACG-C40 as a T4likevirus and vB_EcoS_ACG-M12 as T1likevirus. We assessed the ability of the three phages to eradicate the established biofilm of one of the UPEC strains used in the study. All phages significantly reduced the biofilm within 2–12 h of incubation.

  7. DNA damage under simulated extraterrestrial conditions in bacteriophage T7

    Science.gov (United States)

    Fekete, A.; Módos, K.; Hegedüs, M.; Kovács, G.; Rontó, Gy.; Péter, Á.; Lammer, H.; Panitz, C.

    The experiment "Phage and Uracil response" will be accommodated in the EXPOSE facility of the International Space Station. Its objective is to examine and quantify the effect of specific space conditions on nucleic acid models, especially on bacteriophage T7 and isolated T7 DNA thin films. In order to define the environmental and technical requirements of the EXPOSE, the samples were subjected to the experiment verification test (EVT). During EVT, the samples were exposed to vacuum (10 -4-10 -6 Pa) and polychromatic UV-radiation (200-400 nm) in air, in inert atmosphere, as well as in simulated space vacuum. The effect of extreme temperature in vacuum and the influence of temperature fluctuations around 0 °C were also studied. The total intraphage/isolated DNA damage was determined by quantitative PCR using 555 and 3826 bp fragments of T7 DNA. The type of the damage was resolved using a combination of enzymatic probes and neutral and alkaline agarose gel electrophoresis; the structural/chemical effects were analyzed by spectroscopic and microscopical methods. We obtained substantial evidence that DNA lesions accumulate throughout exposure, but the amount of damage depends on the thickness of the layers. According to our preliminary results, the damages by exposure to conditions of dehydration and UV-irradiation are larger than the sum of vacuum alone, or radiation alone case, suggesting a synergistic action of space vacuum and UV radiation with DNA being the critical target.

  8. Novel lytic bacteriophages from soil that lyse Burkholderia pseudomallei.

    Science.gov (United States)

    Yordpratum, Umaporn; Tattawasart, Unchalee; Wongratanacheewin, Surasakdi; Sermswan, Rasana W

    2011-01-01

    Burkholderia pseudomallei is a Gram-negative saprophytic bacterium that causes severe sepsis with a high mortality rate in humans and a vaccine is not available. Bacteriophages are viruses of bacteria that are ubiquitous in nature. Several lysogenic phages of Burkholderia spp. have been found but information is scarce for lytic phages. Six phages, ST2, ST7, ST70, ST79, ST88 and ST96, which lyse B. pseudomallei, were isolated from soil in an endemic area. The phages belong to the Myoviridae family. The range of estimated genome sizes is 24.0-54.6 kb. Phages ST79 and ST96 lysed 71% and 67% of tested B. pseudomallei isolates and formed plaques on Burkholderia mallei but not other tested bacteria, with the exception of closely related Burkholderia thailandensis which was lysed by ST2 and ST96 only. ST79 and ST96 were observed to clear a mid-log culture by lysis within 6 h when infected at a multiplicity of infection of 0.1. As ST79 and ST96 phages effectively lysed B. pseudomallei, their potential use as a biocontrol of B. pseudomallei in the environment or alternative treatment in infected hosts could lead to benefits from phages that are available in nature. PMID:21091532

  9. Comparative genomics and evolution of the tailed-bacteriophages.

    Science.gov (United States)

    Casjens, Sherwood R

    2005-08-01

    The number of completely sequenced tailed-bacteriophage genomes that have been published increased to more than 125 last year. The comparison of these genomes has brought their highly mosaic nature into much sharper focus. Furthermore, reports of the complete sequences of about 150 bacterial genomes have shown that the many prophage and parts thereof that reside in these bacterial genomes must comprise a significant fraction of Earth's phage gene pool. These phage and prophage genomes are fertile ground for attempts to deduce the nature of viral evolutionary processes, and such analyses have made it clear that these phage have enjoyed a significant level of horizontal exchange of genetic information throughout their long histories. The strength of these evolutionary deductions rests largely on the extensive knowledge that has accumulated during intensive study into the molecular nature of the life cycles of a few 'model system' phages over the past half century. Recent molecular studies of phages other than these model system phages have made it clear that much remains to be learnt about the variety of lifestyle strategies utilized by the tailed-phage. PMID:16019256

  10. Intracellular growth of bacteriophage studied by roentgen irradiation.

    Science.gov (United States)

    LATARJET, R

    1948-07-20

    Growing Escherichia coli infected with bacteriophage T2 was x-rayed during the 21 minute latent period which elapses between infection and lysis of the cells. Survival curves of the infected bacteria were determined almost from minute to minute; they disclosed the following facts which are related to the process of phage growth: During the first 7 minutes, the infective virus particle remains in the cell unique and genetically intact. The host cell synthesizes some ultraviolet-absorbing material probably devoted to building future particles. From the 7th to 9th minute the x-ray resistance of the virus particle increases, probably because of some internal change. Then, multiplication starts and is completed at about the 13th minute, when an average of 130 virulent units is present per cell, displaying an x-ray resistance twice as high as that of the extracellular virus particle. From 13 minutes to the end, the new units progressively recover the x-ray sensitivity of the extracellular virus. Nothing can be said about either the rate of multiplication between 9 and 13 minutes, or the nature of the multiplying units, except that they are more radiation-resistant (probably smaller) than the extracellular virus. The first steps of the growth process are favored by an unknown component of the lysate, different from the active particles. Several particles can grow in the same host cell.

  11. INTRACELLULAR GROWTH OF BACTERIOPHAGE STUDIED BY ROENTGEN IRRADIATION

    Science.gov (United States)

    Latarjet, Raymond

    1948-01-01

    Growing Escherichia coli infected with bacteriophage T2 was x-rayed during the 21 minute latent period which elapses between infection and lysis of the cells. Survival curves of the infected bacteria were determined almost from minute to minute; they disclosed the following facts which are related to the process of phage growth: During the first 7 minutes, the infective virus particle remains in the cell unique and genetically intact. The host cell synthesizes some ultraviolet-absorbing material probably devoted to building future particles. From the 7th to 9th minute the x-ray resistance of the virus particle increases, probably because of some internal change. Then, multiplication starts and is completed at about the 13th minute, when an average of 130 virulent units is present per cell, displaying an x-ray resistance twice as high as that of the extracellular virus particle. From 13 minutes to the end, the new units progressively recover the x-ray sensitivity of the extracellular virus. Nothing can be said about either the rate of multiplication between 9 and 13 minutes, or the nature of the multiplying units, except that they are more radiation-resistant (probably smaller) than the extracellular virus. The first steps of the growth process are favored by an unknown component of the lysate, different from the active particles. Several particles can grow in the same host cell. PMID:18870871

  12. Use of bacteriophage particles displaying influenza virus hemagglutinin for the detection of hemagglutination-inhibition antibodies.

    Science.gov (United States)

    Domm, William; Brewer, Matthew; Baker, Steven F; Feng, Changyong; Martínez-Sobrido, Luis; Treanor, John; Dewhurst, Stephen

    2014-03-01

    Bacteriophage lambda capsids provide a flexible molecular scaffold that can be engineered to display a wide range of exogenous proteins, including full-length viral glycoproteins produced in eukaryotic cells. One application for such particles lies in the detection of virus-specific antibodies, since they may obviate the need to work with infectious stocks of highly pathogenic or emerging viruses that can pose significant biosafety and biocontainment challenges. Bacteriophage lambda capsids were produced that displayed an insect-cell derived, recombinant H5 influenza virus hemagglutinin (HA) on their surface. The particles agglutinated red blood cells efficiently, in a manner that could be blocked using H5 HA-specific monoclonal antibodies. The particles were then used to develop a modified hemagglutinination-inhibition (HAI) assay, which successfully identified human sera with H5 HA-specific HAI activity. These results demonstrate the utility of HA-displaying bacteriophage capsids for the detection of influenza virus-specific HAI antibodies.

  13. Research of pathogenic bacteria and bacteriophages in the residuals of wastewater treatment plants

    International Nuclear Information System (INIS)

    The aim of this study is to find the pathogenic bacteria Listeria and Salmonella and to detect of bacterial (fecal coliforms) and viral indicators (bacteriophage) of fecal contamination in the residues of three sewage treatment plants in Greater Tunis: Charguia, Jdaida and Wardia. Three types of samples were analyzed: raw sewage, treated wastewater and sludge. The study showed the presence of pathogenic bacteria in some samples with a frequency of 7 pour cent for Listeria and 21 pour cent for Salmonella. However, none of these organisms has been detected in treated water of Jdaida and Chargia reflecting the efficiency of the purification process in these stations. Furthermore, all samples were positive for the presence of fecal coliforms and bacteriophages with important titles: up to 8.23 log10 (CFU/L) for coliforms and 8.36 log10 (pfu/L) for bacteriophages.

  14. Magic-angle spinning NMR of intact bacteriophages: Insights into the capsid, DNA and their interface

    Science.gov (United States)

    Abramov, Gili; Morag, Omry; Goldbourt, Amir

    2015-04-01

    Bacteriophages are viruses that infect bacteria. They are complex macromolecular assemblies, which are composed of multiple protein subunits that protect genomic material and deliver it to specific hosts. Various biophysical techniques have been used to characterize their structure in order to unravel phage morphogenesis. Yet, most bacteriophages are non-crystalline and have very high molecular weights, in the order of tens of MegaDaltons. Therefore, complete atomic-resolution characterization on such systems that encompass both capsid and DNA is scarce. In this perspective article we demonstrate how magic-angle spinning solid-state NMR has and is used to characterize in detail bacteriophage viruses, including filamentous and icosahedral phage. We discuss the process of sample preparation, spectral assignment of both capsid and DNA and the use of chemical shifts and dipolar couplings to probe the capsid-DNA interface, describe capsid structure and dynamics and extract structural differences between viruses.

  15. Photochemistry of O(1D) and O(1S) lines in the coma of 67P/Churyumov-Gerasimenko

    Science.gov (United States)

    Cessateur, Gaël; De Keyser, Johan; Maggiolo, Romain; Gibbons, Andrew; Gronoff, Guillaume; Gunell, Herbert; Dhooghe, Frederik; Loreau, Jérôme; Vaeck, Nathalie; Altwegg, Kathrin; Bieler, Andre; Briois, Christelle; Calmonte, Ursina; Combi, Michael; Fuselier, Stephen; Gombosi, Tamas; Haessig, Myrtha; Le Roy, Lena; Neefs, Eddy; Rubin, Martin

    2016-04-01

    We present here a chemistry-emission coupled model to study the production and loss mechanisms of the O(1D) and O(1S) states, for comet 67P/Churyumov-Gerasimenko. The recent discovery of O2 in significant abundance relative to water (3.80% +/- 0.85%, Bieler et al. 2015) within the coma of 67P has been taken into consideration for the first time in such models. We evaluate the effect of the presence of O2 on the green to red-doublet emission intensity ratio, which is traditionally used to assess the CO2 abundance within cometary atmospheres. Model simulations, solving the continuity equation with transport, show that not taking O2 into account leads to an underestimation of the CO2 abundance within 67P. This strongly suggests that the green to red-doublet emission intensity ratio alone is not a proper tool for determining the CO2 abundance, as previously suggested. O2 might indeed be a rather common and abundant parent species, following the re-analysis of the comet 1P/Halley data (Rubin et al. 2015). Therefore, it is likely that earlier determinations of the CO2 abundance in cometary atmospheres have to be revisited.

  16. 鹅FoxO1基因cDNA序列的克隆及组织表达%Cloning and Tissues Expression Analysis of Goose Forkhead Box O1 (FoxO1) Gene cDNA Sequence

    Institute of Scientific and Technical Information of China (English)

    杨璐; 魏守海

    2014-01-01

    为了研究鹅FoxO1(forkhead box O1)基因的功能,根据GenBank已收录的鸡(Gallus gallus)、人(Homo sapiens)和小鼠(Mus musculus)等物种FoxO1基因序列的同源保守区域,设计特异性引物,利用RT-PCR技术克隆鹅FoxO1基因cDNA序列,并对基因序列进行了生物信息学分析.结果表明,成功克隆得到了鹅FoxO1基因cDNA序列,通过BLAST比对,鹅FoxO1基因与原鸡、人、小鼠的核苷酸序列同源性分别为97%、83%、82%,FoxO1基因在四川白鹅中表达水平总体表现为:皮脂>腹脂>腿肌>胸肌>肝脏.因此,FoxO1基因在多个组织中都有表达,且表达差异较大.

  17. Antibacterial Efficacy of Lytic Bacteriophages against Antibiotic-Resistant Klebsiella Species

    Directory of Open Access Journals (Sweden)

    M. Khajeh Karamoddini

    2011-01-01

    Full Text Available Bacterial resistance to antibiotics is a leading and highly prevalent problem in the treatment of infectious diseases. Bacteriophages (phages appear to be effective and safe alternatives for the treatment of resistant infections because of their specificity for bacterial species and lack of infectivity in eukaryotic cells. The present study aimed to isolate bacteriophages against Klebsiella spp. and evaluate their efficacy against antibiotic-resistant species. Seventy-two antibiotic-resistant Klebsiella spp. were isolated from samples of patients who referred to the Ghaem Hospital (Mashhad, Iran. Lytic bacteriophages against Klebsiella spp. were isolated from wastewater of the septic tank of the same hospital. Bactericidal activity of phages against resistant Klebsiella spp. was tested in both liquid (tube method; after 1 and 24 h of incubation and solid (double-layer agar plate method; after 24 h of incubation phases. In each method, three different concentrations of bacteriophages (low: 107 PFU/mL were used. Bacteriophages showed promising bactericidal activity at all assessed concentrations, regardless of the test method and duration of incubation. Overall, bactericidal effects were augmented at higher concentrations. In the tube method, higher activity was observed after 24 h of incubation compared to the 1-h incubation. The bactericidal effects were also higher in the tube method compared to the double-layer agar plate method after 24 h of incubation. The findings of the present study suggest that bacteriophages possess effective bactericidal activity against resistant Klebsiella spp. These bactericidal activities are influenced by phage concentration, duration of incubation, and test method.

  18. Antibacterial efficacy of lytic bacteriophages against antibiotic-resistant Klebsiella species.

    Science.gov (United States)

    Karamoddini, M Khajeh; Fazli-Bazzaz, B S; Emamipour, F; Ghannad, M Sabouri; Jahanshahi, A R; Saed, N; Sahebkar, A

    2011-07-07

    Bacterial resistance to antibiotics is a leading and highly prevalent problem in the treatment of infectious diseases. Bacteriophages (phages) appear to be effective and safe alternatives for the treatment of resistant infections because of their specificity for bacterial species and lack of infectivity in eukaryotic cells. The present study aimed to isolate bacteriophages against Klebsiella spp. and evaluate their efficacy against antibiotic-resistant species. Seventy-two antibiotic-resistant Klebsiella spp. were isolated from samples of patients who referred to the Ghaem Hospital (Mashhad, Iran). Lytic bacteriophages against Klebsiella spp. were isolated from wastewater of the septic tank of the same hospital. Bactericidal activity of phages against resistant Klebsiella spp. was tested in both liquid (tube method; after 1 and 24 h of incubation) and solid (double-layer agar plate method; after 24 h of incubation) phases. In each method, three different concentrations of bacteriophages (low: 10(7) PFU/mL) were used. Bacteriophages showed promising bactericidal activity at all assessed concentrations, regardless of the test method and duration of incubation. Overall, bactericidal effects were augmented at higher concentrations. In the tube method, higher activity was observed after 24 h of incubation compared to the 1-h incubation. The bactericidal effects were also higher in the tube method compared to the double-layer agar plate method after 24 h of incubation. The findings of the present study suggest that bacteriophages possess effective bactericidal activity against resistant Klebsiella spp. These bactericidal activities are influenced by phage concentration, duration of incubation, and test method.

  19. Genomic structure of bacteriophage 6H and its distribution as prophage in Flavobacterium psychrophilum strains

    DEFF Research Database (Denmark)

    Castillo Bermúdez, Daniel Elías; Espejo, Romilio; Middelboe, Mathias

    2014-01-01

    . Here, we present the genome sequence of F. psychrophilum bacteriophage 6H and its distribution as prophage in F. psychrophilum isolates. The DNA sequence revealed a genome of 46 978 bp containing 63 predicted ORFs, of which 13% was assigned a putative function, including an integrase. Sequence analysis...... for the presence of four phage 6H genes (integrase, tail tape protein and two hypothetical proteins) by PCR showed the presence of these prophage genes in 80% of the isolates. In conclusion, we hypothesize that bacteriophage 6H belongs to an abundant group of temperate phages which has lysogenized a large fraction...

  20. Genetic analysis of the bacteriophage T4-encoded cochaperonin Gp31.

    OpenAIRE

    Richardson, A.; Georgopoulos, C

    1999-01-01

    Previous genetic and biochemical analyses have established that the bacteriophage T4-encoded Gp31 is a cochaperonin that interacts with Escherichia coli's GroEL to ensure the timely and accurate folding of Gp23, the bacteriophage-encoded major capsid protein. The heptameric Gp31 cochaperonin, like the E. coli GroES cochaperonin, interacts with GroEL primarily through its unstructured mobile loop segment. Upon binding to GroEL, the mobile loop adopts a structured, beta-hairpin turn. In this ar...

  1. Identification of the bacteriophage T5 dUTPase by protein sequence comparisons.

    Science.gov (United States)

    Kaliman, A V

    1996-01-01

    It is shown by protein sequence comparisons that a 148 amino acid open reading frame (ORF 148) located at 67% of the bacteriophage T5 genome encodes a protein with strong similarity to known dUTPases. This protein contains five characteristic amino acid sequence motifs that are common to the dUTPase gene family. A similarity in size and high degree of sequence identity strongly suggest that the protein encoded by the ORF 148 of bacteriophage T5 is dUTPase. PMID:8988373

  2. Bacteriophages Carrying Antibiotic Resistance Genes in Fecal Waste from Cattle, Pigs, and Poultry▿

    Science.gov (United States)

    Colomer-Lluch, Marta; Imamovic, Lejla; Jofre, Juan; Muniesa, Maite

    2011-01-01

    This study evaluates the occurrence of bacteriophages carrying antibiotic resistance genes in animal environments. blaTEM, blaCTX-M (clusters 1 and 9), and mecA were quantified by quantitative PCR in 71 phage DNA samples from pigs, poultry, and cattle fecal wastes. Densities of 3 to 4 log10 gene copies (GC) of blaTEM, 2 to 3 log10 GC of blaCTX-M, and 1 to 3 log10 GC of mecA per milliliter or gram of sample were detected, suggesting that bacteriophages can be environmental vectors for the horizontal transfer of antibiotic resistance genes. PMID:21807968

  3. The Resistance of Vibrio cholerae O1 El Tor Strains to the Typing Phage 919TP, a Member of K139 Phage Family.

    Science.gov (United States)

    Shen, Xiaona; Zhang, Jingyun; Xu, Jialiang; Du, Pengcheng; Pang, Bo; Li, Jie; Kan, Biao

    2016-01-01

    Bacteriophage 919TP is a temperate phage of Vibrio cholerae serogroup O1 El Tor and is used as a subtyping phage in the phage-biotyping scheme in cholera surveillance in China. In this study, sequencing of the 919TP genome showed that it belonged to the Vibrio phage K139 family. The mechanisms conferring resistance to 919TP infection of El Tor strains were explored to help understand the subtyping basis of phage 919TP and mutations related to 919TP resistance. Among the test strains resistant to phage 919TP, most contained the temperate 919TP phage genome, which facilitated superinfection exclusion to 919TP. Our data suggested that this immunity to Vibrio phage 919TP occurred after absorption of the phage onto the bacteria. Other strains contained LPS receptor synthesis gene mutations that disable adsorption of phage 919TP. Several strains resistant to 919TP infection possessed unknown resistance mechanisms, since they did not contain LPS receptor mutations or temperate K139 phage genome. Further research is required to elucidate the phage infection steps involved in the resistance of these strains to phage infection. PMID:27242744

  4. Quality-controlled small-scale production of a well-defined bacteriophage cocktail for use in human clinical trials.

    Directory of Open Access Journals (Sweden)

    Maya Merabishvili

    Full Text Available We describe the small-scale, laboratory-based, production and quality control of a cocktail, consisting of exclusively lytic bacteriophages, designed for the treatment of Pseudomonas aeruginosa and Staphylococcus aureus infections in burn wound patients. Based on successive selection rounds three bacteriophages were retained from an initial pool of 82 P. aeruginosa and 8 S. aureus bacteriophages, specific for prevalent P. aeruginosa and S. aureus strains in the Burn Centre of the Queen Astrid Military Hospital in Brussels, Belgium. This cocktail, consisting of P. aeruginosa phages 14/1 (Myoviridae and PNM (Podoviridae and S. aureus phage ISP (Myoviridae was produced and purified of endotoxin. Quality control included Stability (shelf life, determination of pyrogenicity, sterility and cytotoxicity, confirmation of the absence of temperate bacteriophages and transmission electron microscopy-based confirmation of the presence of the expected virion morphologic particles as well as of their specific interaction with the target bacteria. Bacteriophage genome and proteome analysis confirmed the lytic nature of the bacteriophages, the absence of toxin-coding genes and showed that the selected phages 14/1, PNM and ISP are close relatives of respectively F8, phiKMV and phage G1. The bacteriophage cocktail is currently being evaluated in a pilot clinical study cleared by a leading Medical Ethical Committee.

  5. Isolation and characterization of glacier VMY22, a novel lytic cold-active bacteriophage of Bacillus cereus

    Institute of Scientific and Technical Information of China (English)

    Xiuling; Ji; Chunjing; Zhang; Yuan; Fang; Qi; Zhang; Lianbing; Lin; Bing; Tang; Yunlin; Wei

    2015-01-01

    As a unique ecological system with low temperature and low nutrient levels, glaciers are considered a "living fossil" for the research of evolution. In this work, a lytic cold-active bacteriophage designated VMY22 against Bacillus cereus MYB41-22 was isolated from Mingyong Glacier in China, and its characteristics were studied. Electron microscopy revealed that VMY22 has an icosahedral head(59.2 nm in length, 31.9 nm in width) and a tail(43.2 nm in length). Bacteriophage VMY22 was classified as a Podoviridae with an approximate genome size of 18 to 20 kb. A one-step growth curve revealed that the latent and the burst periods were 70 and 70 min, respectively, with an average burst size of 78 bacteriophage particles per infected cell. The pH and thermal stability of bacteriophage VMY22 were also investigated. The maximum stability of the bacteriophage was observed to be at pH 8.0 and it was comparatively stable at p H 5.0–9.0. As VMY22 is a cold-active bacteriophage with low production temperature, its characterization and the relationship between MYB41-22 and Bacillus cereus bacteriophage deserve further study.

  6. Simultaneous Identification and Susceptibility Determination to Multiple Antibiotics of Staphylococcus aureus by Bacteriophage Amplification Detection Combined with Mass Spectrometry.

    Science.gov (United States)

    Rees, Jon C; Pierce, Carrie L; Schieltz, David M; Barr, John R

    2015-07-01

    The continued advance of antibiotic resistance in clinically relevant bacterial strains necessitates the development and refinement of assays that can rapidly and cost-effectively identify bacteria and determine their susceptibility to a panel of antibiotics. A methodology is described herein that exploits the specificity and physiology of the Staphylococci bacteriophage K to identify Staphylococcus aureus (S. aureus) and determine its susceptibility to clindamycin and cefoxitin. The method uses liquid chromatography-mass spectrometry to monitor the replication of bacteriophage after it is used to infect samples thought to contain S. aureus. Amplification of bacteriophage K indicates the sample contains S. aureus, for it is only in the presence of a suitable host that bacteriophage K can amplify. If bacteriophage amplification is detected in samples containing the antibiotics clindamycin or cefoxitin, the sample is deemed to be resistant to these antibiotics, respectively, for bacteriophage can only amplify in a viable host. Thus, with a single work flow, S. aureus can be detected in an unknown sample and susceptibility to clindamycin and cefoxitin can be ascertained. This Article discusses implications for the use of bacteriophage amplification in the clinical laboratory.

  7. A bacteriophage detection tool for viability assessment of Salmonella cells.

    Science.gov (United States)

    Fernandes, E; Martins, V C; Nóbrega, C; Carvalho, C M; Cardoso, F A; Cardoso, S; Dias, J; Deng, D; Kluskens, L D; Freitas, P P; Azeredo, J

    2014-02-15

    Salmonellosis, one of the most common food and water-borne diseases, has a major global health and economic impact. Salmonella cells present high infection rates, persistence over inauspicious conditions and the potential to preserve virulence in dormant states when cells are viable but non-culturable (VBNC). These facts are challenging for current detection methods. Culture methods lack the capacity to detect VBNC cells, while biomolecular methods (e.g. DNA- or protein-based) hardly distinguish between dead innocuous cells and their viable lethal counterparts. This work presents and validates a novel bacteriophage (phage)-based microbial detection tool to detect and assess Salmonella viability. Salmonella Enteritidis cells in a VBNC physiological state were evaluated by cell culture, flow-cytometry and epifluorescence microscopy, and further assayed with a biosensor platform. Free PVP-SE1 phages in solution showed the ability to recognize VBNC cells, with no lysis induction, in contrast to the minor recognition of heat-killed cells. This ability was confirmed for immobilized phages on gold surfaces, where the phage detection signal follows the same trend of the concentration of viable plus VBNC cells in the sample. The phage probe was then tested in a magnetoresistive biosensor platform allowing the quantitative detection and discrimination of viable and VBNC cells from dead cells, with high sensitivity. Signals arising from 3 to 4 cells per sensor were recorded. In comparison to a polyclonal antibody that does not distinguish viable from dead cells, the phage selectivity in cell recognition minimizes false-negative and false-positive results often associated with most detection methods.

  8. Bacteriophage Amplification-Coupled Detection and Identification of Bacterial Pathogens

    Science.gov (United States)

    Cox, Christopher R.; Voorhees, Kent J.

    Current methods of species-specific bacterial detection and identification are complex, time-consuming, and often require expensive specialized equipment and highly trained personnel. Numerous biochemical and genotypic identification methods have been applied to bacterial characterization, but all rely on tedious microbiological culturing practices and/or costly sequencing protocols which render them impractical for deployment as rapid, cost-effective point-of-care or field detection and identification methods. With a view towards addressing these shortcomings, we have exploited the evolutionarily conserved interactions between a bacteriophage (phage) and its bacterial host to develop species-specific detection methods. Phage amplification-coupled matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS) was utilized to rapidly detect phage propagation resulting from species-specific in vitro bacterial infection. This novel signal amplification method allowed for bacterial detection and identification in as little as 2 h, and when combined with disulfide bond reduction methods developed in our laboratory to enhance MALDI-TOF-MS resolution, was observed to lower the limit of detection by several orders of magnitude over conventional spectroscopy and phage typing methods. Phage amplification has been combined with lateral flow immunochromatography (LFI) to develop rapid, easy-to-operate, portable, species-specific point-of-care (POC) detection devices. Prototype LFI detectors have been developed and characterized for Yersinia pestis and Bacillus anthracis, the etiologic agents of plague and anthrax, respectively. Comparable sensitivity and rapidity was observed when phage amplification was adapted to a species-specific handheld LFI detector, thus allowing for rapid, simple, POC bacterial detection and identification while eliminating the need for bacterial culturing or DNA isolation and amplification techniques.

  9. DNA damage under simulated extraterrestrial conditions in bacteriophage T7

    Science.gov (United States)

    Fekete, A.; Kovács, G.; Hegedüs, M.; Módos, K.; Rontó, Gy.; Lammer, H.; Panitz, C.

    The experiment ``Phage and uracil response'' (PUR) will be accommodated in the EXPOSE facility of the ISS aiming to examine and quantify the effect of specific space conditions on bacteriophage T7 and isolated T7 DNA thin films. To achieve this new method was elaborated for the preparation of DNA and nucleoprotein thin films (1). During the EXPOSE Experiment Verification Tests (EVT) the samples were exposed to vacuum (10 -6 Pa), to monochromatic (254 nm) and polychromatic (200-400 nm) UV radiation in air as well in simulated space vacuum. Using neutral density (ND) filters dose-effect curves were performed in order to define the maximum doses tolerated, and we also studied the effect of temperature in vacuum as well as the influence of temperature fluctuations. We obtained substantial evidence that DNA lesions (e.g. strand breaks, DNA-protein cross-links, DNA-DNA cross-links) accumulate throughout exposure. DNA damage was determined by quantitative PCR using 555 bp and 3826 bp fragments of T7 DNA (2) and by neutral and alkaline agarose gel electrophoresis; the structural/chemical effects were analyzed by spectroscopic and microscopical methods. Characteristic changes in the absorption spectrum, in the electrophoretic pattern of DNA and the decrease of the amount of the PCR products have been detected indicating the damage of isolated and intraphage DNA. Preliminary results suggest a synergistic action of space vacuum and UV radiation with DNA being the critical target. Fekete et al. J. Luminescence 102-103, 469-475, 2003 Hegedüs et al. Photochem. Photobiol. 78, 213-219, 2003

  10. Switching the polarity of a bacteriophage integration system.

    Science.gov (United States)

    Smith, Matthew C A; Till, Rob; Smith, Margaret C M

    2004-03-01

    During lysogenic growth many temperate bacteriophage genomes are integrated into the host's chromosome and efficient integration and excision are therefore an essential part of the phage life cycle. The Streptomyces phage phiC31 encodes an integrase related to the resolvase/invertases and is evolutionarily and mechanistically distinct from the integrase of phage lambda. We show that during phiC31 integration the polarity of the recombination sites, attB and attP, is dependent on the sequences of the two base pairs (bp) where crossover occurs. A loss or switch in polarity of the recombination sites can occur by mutation of this dinucleotide, leading to incorrectly joined products. The properties of the mutant sites implies that phiC31 integrase interacts symmetrically with the substrates, which during synapsis can align apparently freely in either of two alternative forms that lead to correct or incorrect joining of products. Analysis of the topologies of the reaction products provided evidence that integrase can synapse and activate strand exchange even when recombinant products cannot form due to mismatches at the crossover site. The topologies of the recombination products are complex and indicative of multiple pathways to product formation. The efficiency of integration of a phiC31 derivative, KC859, into an attB site with switched polarity was assayed in vivo and shown to be no different from integration into a wild-type attB. Thus neither the host nor KC859 express a factor that influences the alignment of the recombination sites at synapsis.

  11. Self-assembly of silver nanoparticles and bacteriophage

    Directory of Open Access Journals (Sweden)

    Santi Scibilia

    2016-03-01

    Full Text Available Biohybrid nanostructured materials, composed of both inorganic nanoparticles and biomolecules, offer prospects for many new applications in extremely diverse fields such as chemistry, physics, engineering, medicine and nanobiotechnology. In the recent years, Phage display technique has been extensively used to generate phage clones displaying surface peptides with functionality towards organic materials. Screening and selection of phage displayed material binding peptides has attracted great interest because of their use for development of hybrid materials with multiple functionalities. Here, we present a self-assembly approach for the construction of hybrid nanostructured networks consisting of M13 P9b phage clone, specific for Pseudomonas aeruginosa, selected by Phage display technology, directly assembled with silver nanoparticles (AgNPs, previously prepared by pulsed laser ablation. These networks are characterized by UV–vis optical spectroscopy, scanning/transmission electron microscopies and Raman spectroscopy. We investigated the influence of different ions and medium pH on self-assembly by evaluating different phage suspension buffers. The assembly of these networks is controlled by electrostatic interactions between the phage pVIII major capsid proteins and the AgNPs. The formation of the AgNPs-phage networks was obtained only in two types of tested buffers at a pH value near the isoelectric point of each pVIII proteins displayed on the surface of the clone. This systematic study allowed to optimize the synthesis procedure to assembly AgNPs and bacteriophage. Such networks find application in the biomedical field of advanced biosensing and targeted gene and drug delivery.

  12. Novel DNA packaging recognition in the unusual bacteriophage N15

    International Nuclear Information System (INIS)

    Phage lambda's cosB packaging recognition site is tripartite, consisting of 3 TerS binding sites, called R sequences. TerS binding to the critical R3 site positions the TerL endonuclease for nicking cosN to generate cohesive ends. The N15 cos (cosN15) is closely related to cosλ, but whereas the cosBN15 subsite has R3, it lacks the R2 and R1 sites and the IHF binding site of cosBλ. A bioinformatic study of N15-like phages indicates that cosBN15 also has an accessory, remote rR2 site, which is proposed to increase packaging efficiency, like R2 and R1 of lambda. N15 plus five prophages all have the rR2 sequence, which is located in the TerS-encoding 1 gene, approximately 200 bp distal to R3. An additional set of four highly related prophages, exemplified by Monarch, has R3 sequence, but also has R2 and R1 sequences characteristic of cosB–λ. The DNA binding domain of TerS-N15 is a dimer. - Highlights: • There are two classes of DNA packaging signals in N15-related phages. • Phage N15's TerS binding site: a critical site and a possible remote accessory site. • Viral DNA recognition signals by the λ-like bacteriophages: the odd case of N15

  13. Novel DNA packaging recognition in the unusual bacteriophage N15

    Energy Technology Data Exchange (ETDEWEB)

    Feiss, Michael [Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242 (United States); Geyer, Henriette, E-mail: henriettegeyer@gmail.com [Division of Viral Infections, Robert Koch Institute, Berlin (Germany); Division of Viral Infections, Robert Koch Institute, Berlin (Germany); Klingberg, Franco, E-mail: franco.klingberg@thermofisher.com [Flow Cytometry, Imaging & Microscopy, Thermo Fisher Scientific, Frankfurter Strasse 129B 64293 Darmstadt (Germany); Flow Cytometry, Imaging & Microscopy, Thermo Fisher Scientific, Frankfurter Strasse 129B 64293 Darmstadt (Germany); Moreno, Norma, E-mail: nmoreno@islander.tamucc.edu [Texas A& M University – Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78412, United States. (United States); Texas A& M University – Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78412, United States. (United States); Forystek, Amanda, E-mail: eamanda-forystek@uiowa.edu [Flow Cytometry, Imaging & Microscopy, Thermo Fisher Scientific, Frankfurter Strasse 129B 64293 Darmstadt (Germany); Room # 2911 JPP, Dept. of Psychiatry, The University of Iowa, 200 Hawkins Drive, Iowa City, Iowa, 52242 (United States); Maluf, Nasib Karl, E-mail: fKarl.Maluf@ap-lab.com [Flow Cytometry, Imaging & Microscopy, Thermo Fisher Scientific, Frankfurter Strasse 129B 64293 Darmstadt (Germany); Alliance Protein Laboratories, Inc. 6042 Cornerstone Court West, Suite ASan Diego, CA 92121, USA. (United States); Sippy, Jean [Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242 (United States)

    2015-08-15

    Phage lambda's cosB packaging recognition site is tripartite, consisting of 3 TerS binding sites, called R sequences. TerS binding to the critical R3 site positions the TerL endonuclease for nicking cosN to generate cohesive ends. The N15 cos (cos{sup N15}) is closely related to cos{sup λ}, but whereas the cosB{sup N15} subsite has R3, it lacks the R2 and R1 sites and the IHF binding site of cosB{sup λ}. A bioinformatic study of N15-like phages indicates that cosB{sup N15} also has an accessory, remote rR2 site, which is proposed to increase packaging efficiency, like R2 and R1 of lambda. N15 plus five prophages all have the rR2 sequence, which is located in the TerS-encoding 1 gene, approximately 200 bp distal to R3. An additional set of four highly related prophages, exemplified by Monarch, has R3 sequence, but also has R2 and R1 sequences characteristic of cosB–λ. The DNA binding domain of TerS-N15 is a dimer. - Highlights: • There are two classes of DNA packaging signals in N15-related phages. • Phage N15's TerS binding site: a critical site and a possible remote accessory site. • Viral DNA recognition signals by the λ-like bacteriophages: the odd case of N15.

  14. Dynamics of bacteriophage genome ejection in vitro and in vivo

    Science.gov (United States)

    Panja, Debabrata; Molineux, Ian J.

    2010-12-01

    Bacteriophages, phages for short, are viruses of bacteria. The majority of phages contain a double-stranded DNA genome packaged in a capsid at a density of ~500 mg ml-1. This high density requires substantial compression of the normal B-form helix, leading to the conjecture that DNA in mature phage virions is under significant pressure, and that pressure is used to eject the DNA during infection. A large number of theoretical, computer simulation and in vitro experimental studies surrounding this conjecture have revealed many—though often isolated and/or contradictory—aspects of packaged DNA. This prompts us to present a unified view of the statistical physics and thermodynamics of DNA packaged in phage capsids. We argue that the DNA in a mature phage is in a (meta)stable state, wherein electrostatic self-repulsion is balanced by curvature stress due to confinement in the capsid. We show that in addition to the osmotic pressure associated with the packaged DNA and its counterions, there are four different pressures within the capsid: pressure on the DNA, hydrostatic pressure, the pressure experienced by the capsid and the pressure associated with the chemical potential of DNA ejection. Significantly, we analyze the mechanism of force transmission in the packaged DNA and demonstrate that the pressure on DNA is not important for ejection. We derive equations showing a strong hydrostatic pressure difference across the capsid shell. We propose that when a phage is triggered to eject by interaction with its receptor in vitro, the (thermodynamic) incentive of water molecules to enter the phage capsid flushes the DNA out of the capsid. In vivo, the difference between the osmotic pressures in the bacterial cell cytoplasm and the culture medium similarly results in a water flow that drags the DNA out of the capsid and into the bacterial cell.

  15. Mobile CRISPR/Cas-mediated bacteriophage resistance in Lactococcus lactis.

    Directory of Open Access Journals (Sweden)

    Anne M Millen

    Full Text Available Lactococcus lactis is a biotechnological workhorse for food fermentations and potentially therapeutic products and is therefore widely consumed by humans. It is predominantly used as a starter microbe for fermented dairy products, and specialized strains have adapted from a plant environment through reductive evolution and horizontal gene transfer as evidenced by the association of adventitious traits with mobile elements. Specifically, L. lactis has armed itself with a myriad of plasmid-encoded bacteriophage defensive systems to protect against viral predation. This known arsenal had not included CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated proteins, which forms a remarkable microbial immunity system against invading DNA. Although CRISPR/Cas systems are common in the genomes of closely related lactic acid bacteria (LAB, none was identified within the eight published lactococcal genomes. Furthermore, a PCR-based search of the common LAB CRISPR/Cas systems (Types I and II in 383 industrial L. lactis strains proved unsuccessful. Here we describe a novel, Type III, self-transmissible, plasmid-encoded, phage-interfering CRISPR/Cas discovered in L. lactis. The native CRISPR spacers confer resistance based on sequence identity to corresponding lactococcal phage. The interference is directed at phages problematic to the dairy industry, indicative of a responsive system. Moreover, targeting could be modified by engineering the spacer content. The 62.8-kb plasmid was shown to be conjugally transferrable to various strains. Its mobility should facilitate dissemination within microbial communities and provide a readily applicable system to naturally introduce CRISPR/Cas to industrially relevant strains for enhanced phage resistance and prevention against acquisition of undesirable genes.

  16. Dynamics of bacteriophage genome ejection in vitro and in vivo

    International Nuclear Information System (INIS)

    Bacteriophages, phages for short, are viruses of bacteria. The majority of phages contain a double-stranded DNA genome packaged in a capsid at a density of ∼500 mg ml−1. This high density requires substantial compression of the normal B-form helix, leading to the conjecture that DNA in mature phage virions is under significant pressure, and that pressure is used to eject the DNA during infection. A large number of theoretical, computer simulation and in vitro experimental studies surrounding this conjecture have revealed many—though often isolated and/or contradictory—aspects of packaged DNA. This prompts us to present a unified view of the statistical physics and thermodynamics of DNA packaged in phage capsids. We argue that the DNA in a mature phage is in a (meta)stable state, wherein electrostatic self-repulsion is balanced by curvature stress due to confinement in the capsid. We show that in addition to the osmotic pressure associated with the packaged DNA and its counterions, there are four different pressures within the capsid: pressure on the DNA, hydrostatic pressure, the pressure experienced by the capsid and the pressure associated with the chemical potential of DNA ejection. Significantly, we analyze the mechanism of force transmission in the packaged DNA and demonstrate that the pressure on DNA is not important for ejection. We derive equations showing a strong hydrostatic pressure difference across the capsid shell. We propose that when a phage is triggered to eject by interaction with its receptor in vitro, the (thermodynamic) incentive of water molecules to enter the phage capsid flushes the DNA out of the capsid. In vivo, the difference between the osmotic pressures in the bacterial cell cytoplasm and the culture medium similarly results in a water flow that drags the DNA out of the capsid and into the bacterial cell

  17. An Ensemble Method to Distinguish Bacteriophage Virion from Non-Virion Proteins Based on Protein Sequence Characteristics

    Directory of Open Access Journals (Sweden)

    Lina Zhang

    2015-09-01

    Full Text Available Bacteriophage virion proteins and non-virion proteins have distinct functions in biological processes, such as specificity determination for host bacteria, bacteriophage replication and transcription. Accurate identification of bacteriophage virion proteins from bacteriophage protein sequences is significant to understand the complex virulence mechanism in host bacteria and the influence of bacteriophages on the development of antibacterial drugs. In this study, an ensemble method for bacteriophage virion protein prediction from bacteriophage protein sequences is put forward with hybrid feature spaces incorporating CTD (composition, transition and distribution, bi-profile Bayes, PseAAC (pseudo-amino acid composition and PSSM (position-specific scoring matrix. When performing on the training dataset 10-fold cross-validation, the presented method achieves a satisfactory prediction result with a sensitivity of 0.870, a specificity of 0.830, an accuracy of 0.850 and Matthew’s correlation coefficient (MCC of 0.701, respectively. To evaluate the prediction performance objectively, an independent testing dataset is used to evaluate the proposed method. Encouragingly, our proposed method performs better than previous studies with a sensitivity of 0.853, a specificity of 0.815, an accuracy of 0.831 and MCC of 0.662 on the independent testing dataset. These results suggest that the proposed method can be a potential candidate for bacteriophage virion protein prediction, which may provide a useful tool to find novel antibacterial drugs and to understand the relationship between bacteriophage and host bacteria. For the convenience of the vast majority of experimental Int. J. Mol. Sci. 2015, 16 21735 scientists, a user-friendly and publicly-accessible web-server for the proposed ensemble method is established.

  18. Isolation and Genetic Analysis of an Environmental Bacteriophage: A 10-Session Laboratory Series in Molecular Virology

    Science.gov (United States)

    Williamson, Ryan P.; Barker, Brent T.; Drammeh, Hamidou; Scott, Jefferson; Lin, Joseph

    2014-01-01

    Bacterial viruses, otherwise known as bacteriophage (or phage), are some of the most abundant viruses found in the environment. They can be easily isolated from water or soil and are ideal for use in laboratory classrooms due to their ease of culture and inherent safety. Here, we describe a series of 10 laboratory exercises where students collect,…

  19. Occurrence of Salmonella-specific bacteriophages in swine feces collected from commercial farms

    Science.gov (United States)

    Salmonella is one of the primary foodborne pathogens associated with swine production and represents a significant threat to human health. Bacteriophage are naturally-occurring viruses that prey on bacteria and have been suggested as a potential intervention strategy to reduce Salmonella in food an...

  20. Bacteriophages and their applications in the diagnosis and treatment of hepatitis B virus infection

    Science.gov (United States)

    Bakhshinejad, Babak; Sadeghizadeh, Majid

    2014-01-01

    Hepatitis B virus (HBV) infection is a major global health challenge leading to serious disorders such as cirrhosis and hepatocellular carcinoma. Currently, there exist various diagnostic and therapeutic approaches for HBV infection. However, prevalence and hazardous effects of chronic viral infection heighten the need to develop novel methodologies for the detection and treatment of this infection. Bacteriophages, viruses that specifically infect bacterial cells, with a long-established tradition in molecular biology and biotechnology have recently been introduced as novel tools for the prevention, diagnosis and treatment of HBV infection. Bacteriophages, due to tremendous genetic flexibility, represent potential to undergo a huge variety of surface modifications. This property has been the rationale behind introduction of phage display concept. This powerful approach, together with combinatorial chemistry, has shaped the concept of phage display libraries with diverse applications for the detection and therapy of HBV infection. This review aims to offer an insightful overview of the potential of bacteriophages in the development of helpful prophylactic (vaccine design), diagnostic and therapeutic strategies for HBV infection thereby providing new perspectives to the growing field of bacteriophage researches directing towards HBV infection. PMID:25206272

  1. 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

    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...

  2. Campylobacter jejuni motility is required for infection of the flagellotropic bacteriophage F341

    DEFF Research Database (Denmark)

    Baldvinsson, Signe Berg; Sørensen, Martine Camilla Holst; Vegge, Christina Skovgaard;

    2014-01-01

    Previous studies have identified a specific modification of the capsular polysaccharide as receptor for phages that infect Campylobacter jejuni. Using acapsular kpsM mutants of C. jejuni strains NCTC11168 and NCTC12658, we found that bacteriophage F341 infects C. jejuni independently of the capsule...

  3. The effectiveness of bacteriophages against methicillin-resistant Staphylococcus aureus ST398 nasal colonization in pigs

    NARCIS (Netherlands)

    Verstappen, Koen M.; Tulinski, Pawel; Duim, Birgitta; Fluit, Ad C.; Carney, Jennifer; Nes, Van Arie; Wagenaar, Jaap A.

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important colonizer in animals and an opportunistic pathogen in humans. In humans, MRSA can cause infections that might be difficult to treat because of antimicrobial resistance. The use of bacteriophages has been suggested as a potential a

  4. Key Players in the Genetic Switch of Bacteriophage TP901-1

    DEFF Research Database (Denmark)

    Alsing, Anne; Pedersen, Margit; Sneppen, Kim;

    2011-01-01

    the bistable genetic switch of bacteriophage TP901-1 through experiments and statistical mechanical modeling. We examine the activity of the lysogenic promoter Pr at different concentrations of the phage repressor, CI, and compare the effect of CI on Pr in the presence or absence of the phage-encoded MOR...

  5. Optimal foraging predicts the ecology but not the evolution of host specialization in bacteriophages.

    Directory of Open Access Journals (Sweden)

    Sébastien Guyader

    Full Text Available We explore the ability of optimal foraging theory to explain the observation among marine bacteriophages that host range appears to be negatively correlated with host abundance in the local marine environment. We modified Charnov's classic diet composition model to describe the ecological dynamics of the related generalist and specialist bacteriophages phiX174 and G4, and confirmed that specialist phages are ecologically favored only at high host densities. Our modified model accurately predicted the ecological dynamics of phage populations in laboratory microcosms, but had only limited success predicting evolutionary dynamics. We monitored evolution of attachment rate, the phenotype that governs diet breadth, in phage populations adapting to both low and high host density microcosms. Although generalist phiX174 populations evolved even broader diets at low host density, they did not show a tendency to evolve the predicted specialist foraging strategy at high host density. Similarly, specialist G4 populations were unable to evolve the predicted generalist foraging strategy at low host density. These results demonstrate that optimal foraging models developed to explain the behaviorally determined diets of predators may have only limited success predicting the genetically determined diets of bacteriophage, and that optimal foraging probably plays a smaller role than genetic constraints in the evolution of host specialization in bacteriophages.

  6. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN...

  7. Creating highly amplified enzyme-linked immunosorbent assay signals from genetically engineered bacteriophage.

    Science.gov (United States)

    Brasino, Michael; Lee, Ju Hun; Cha, Jennifer N

    2015-02-01

    For early detection of many diseases, it is critical to be able to diagnose small amounts of biomarkers in blood or serum. One of the most widely used sensing assays is the enzyme-linked immunosorbent assay (ELISA), which typically uses detection monoclonal antibodies conjugated to enzymes to produce colorimetric signals. To increase the overall sensitivities of these sensors, we demonstrate the use of a dually modified version of filamentous bacteriophage Fd that produces significantly higher colorimetric signals in ELISAs than what can be achieved using antibodies alone. Because only a few proteins at the tip of the micron-long bacteriophage are involved in antigen binding, the approximately 4000 other coat proteins can be augmented-by either chemical functionalization or genetic engineering-with hundreds to thousands of functional groups. In this article, we demonstrate the use of bacteriophage that bear a large genomic fusion that allows them to bind specific antibodies on coat protein 3 (p3) and multiple biotin groups on coat protein 8 (p8) to bind to avidin-conjugated enzymes. In direct ELISAs, the anti-rTNFα (recombinant human tumor necrosis factor alpha)-conjugated bacteriophage show approximately 3- to 4-fold gains in signal over that of anti-rTNFα, demonstrating their use as a platform for highly sensitive protein detection.

  8. Induction of genetic recombination in the lambda bacteriophage by ultraviolet radiation of the Escherichia Coli cells

    International Nuclear Information System (INIS)

    In this work there are reported the results that show that although the stimulation of the recombination of the Lambda bacteriophage, by UV irradiation of the cells of Escherichia Coli, it looks to be the result of the high expression of the functions of the SOS system, doesn't keep some relationship with the high concentration of protein reached RecA. (Author)

  9. Characterization of Φ2954, a newly isolated bacteriophage containing three dsRNA genomic segments

    Directory of Open Access Journals (Sweden)

    Di Sanzo Fabiana

    2010-02-01

    Full Text Available Abstract Background Bacteriophage Φ12 is a member of the Cystoviridae and is distinct from Φ6, the first member of that family. We have recently isolated a number of related phages and five showed high similarity to Φ12 in the amino acid sequences of several proteins. Bacteriophage Φ2954 is a member of this group. Results Φ2954 was isolated from radish leaves and was found to have a genome of three segments of double-stranded RNA (dsRNA, placing it in the Cystoviridae. The base sequences for many of the genes and for the segment termini were similar but not identical to those of bacteriophage Φ12. However, the host specificity was for the type IV pili of Pseudomonas syringae HB10Y rather than for the rough LPS to which Φ12 attaches. Reverse genetics techniques enabled the production of infectious phage from cDNA copies of the genome. Phage were constructed with one, two or three genomic segments. Phage were also produced with altered transcriptional regulation. Although the pac sequences of Φ2954 show no similarity to those of Φ12, segment M of Φ2954 could be acquired by Φ12 resulting in a change of host specificity. Conclusions We have isolated a new member of the bacteriophage family Cystoviridae and find that although it shows similarity to other members of the family, it has unique properties that help to elucidate viral strategies for genomic packaging and gene expression.

  10. The membrane-bound form of gene 9 minor coat protein of bacteriophage M13

    NARCIS (Netherlands)

    Houbiers, M.C.

    2002-01-01

    Bacteriophage M13 is a virus that infects the bacteria Escherichia coli ( E. coli ), a single cell organism that resides in our intestines. It consists of the cytoplasm (contents) and a double membrane that keeps the contents together (the barrier to the outside world). The membra

  11. Transfection of Bacillus subtilis protoplasts by bacteriophage phi do7 DNA.

    OpenAIRE

    Perkins, J B; Dean, D H

    1983-01-01

    DNA from the Bacillus subtilis temperate bacteriophage phi do7 was found to efficiently transfect B. subtilis protoplasts; protoplast transfection was more efficient than competent cell transfection by a magnitude of 10(3). Unlike competent cell transfection, protoplast transfection did not require primary recombination, suggesting that phi do7 DNA enters the protoplast as double-stranded molecules.

  12. Problem-Solving Test: RNA and Protein Synthesis in Bacteriophage-Infected "E. coli" Cells

    Science.gov (United States)

    Szeberenyi, Jozsef

    2008-01-01

    The classic experiment presented in this problem-solving test was designed to identify the template molecules of translation by analyzing the synthesis of phage proteins in "Escherichia coli" cells infected with bacteriophage T4. The work described in this test led to one of the most seminal discoveries of early molecular biology: it dealt a…

  13. Isolation of Salmonella spp. and bacteriophage active against Salmonella spp. from commercial swine

    Science.gov (United States)

    Bacteriophage are viruses that prey on bacteria and may be a potential strategy to reduce foodborne pathogenic bacteria in the gastrointestinal tract of food animals. Phages are fairly common in the gastrointestinal microbial ecosystem of mammals, but the incidence is unknown. If phage are to be e...

  14. Removal of endotoxins from bacteriophage preparations by extraction with organic solvents.

    Directory of Open Access Journals (Sweden)

    Bożena Szermer-Olearnik

    Full Text Available Lipopolysaccharide (LPS, endotoxin, pyrogen constitutes a very troubling contaminant of crude phage lysates produced in Gram-negative bacteria. Toxicity of LPS depends on the strong innate immunity response including the cytokines. Therefore, its removal is important for bacteriophage applications. In this paper, we present a procedure for extractive removal of endotoxin from bacteriophage preparations with water immiscible solvents (1-octanol or 1-butanol. During extraction most of the phage lytic activity is retained in the aqueous phase, while endotoxin accumulates in the organic solvent. The levels of endotoxin (expressed as endotoxin units, EU in the aqueous bacteriophage-containing fraction determined by limulus amebocyte lysate or EndoLISA assay were exceptionally low. While the initial endotoxin levels in the crude phage lysates ranged between 10(3 and 10(5 EU/ml the average level after organic extraction remaining in the aqueous fraction was 5.3 EU/ml. These values when related to phage titers decreased from 10(3-10(5 EU/10(9 PFU (plaque forming units down to an average of 2.8 EU/10(9 PFU. The purification procedure is scalable, efficient and applicable to all the bacteriophages tested: T4, HAP1 (E. coli and F8 (P. aeruginosa.

  15. A highly abundant bacteriophage discovered in the unknown sequences of human faecal metagenomes

    NARCIS (Netherlands)

    Dutilh, B.E.; Cassman, N.; McNair, K.; Sanchez, S.E.; Silva, G.G.; Boling, L.; Barr, J.J.; Speth, D.R.; Seguritan, V.; Aziz, R.K.; Felts, B.; Dinsdale, E.A.; Mokili, J.L.; Edwards, R.A.

    2014-01-01

    Metagenomics, or sequencing of the genetic material from a complete microbial community, is a promising tool to discover novel microbes and viruses. Viral metagenomes typically contain many unknown sequences. Here we describe the discovery of a previously unidentified bacteriophage present in the ma

  16. Genome Sequence of the Enterohemorrhagic Escherichia coli Bacteriophage UFV-AREG1

    Science.gov (United States)

    Batalha, Laís Silva; Albino, Luiz Augusto A.; Boggione, Delaine Meireles Gouveia; Gontijo, Marco Tulio Pardini; Bazzolli, Denise M. Soares; Mendonca, Regina C. Santos

    2016-01-01

    Here, we present the genome sequence of the Escherichia coli bacteriophage UFV-AREG1. This phage was isolated from cowshed wastewater and showed specificity for enterohemorrhagic E. coli O157:H7 (ATCC 43895), E. coli 0111 (CDC O11ab) and E. coli (ATCC 23229). PMID:27738021

  17. Bacteriophages and their applications in the diagnosis and treatment of hepatitis B virus infection.

    Science.gov (United States)

    Bakhshinejad, Babak; Sadeghizadeh, Majid

    2014-09-01

    Hepatitis B virus (HBV) infection is a major global health challenge leading to serious disorders such as cirrhosis and hepatocellular carcinoma. Currently, there exist various diagnostic and therapeutic approaches for HBV infection. However, prevalence and hazardous effects of chronic viral infection heighten the need to develop novel methodologies for the detection and treatment of this infection. Bacteriophages, viruses that specifically infect bacterial cells, with a long-established tradition in molecular biology and biotechnology have recently been introduced as novel tools for the prevention, diagnosis and treatment of HBV infection. Bacteriophages, due to tremendous genetic flexibility, represent potential to undergo a huge variety of surface modifications. This property has been the rationale behind introduction of phage display concept. This powerful approach, together with combinatorial chemistry, has shaped the concept of phage display libraries with diverse applications for the detection and therapy of HBV infection. This review aims to offer an insightful overview of the potential of bacteriophages in the development of helpful prophylactic (vaccine design), diagnostic and therapeutic strategies for HBV infection thereby providing new perspectives to the growing field of bacteriophage researches directing towards HBV infection.

  18. 76 FR 66187 - Bacteriophage of Clavibacter Michiganensis Subspecies Michiganensis; Exemption From the...

    Science.gov (United States)

    2011-10-26

    ... December 28, 2005 (70 FR 76704) (FRL-7753-6)). Much like the previously registered bacteriophage, Omni... Findings In the Federal Register of September 23, 2009 (74 FR 48556) (FRL- 8434-7), EPA issued a notice... from review under Executive Order 12866, entitled Regulatory Planning and Review (58 FR 51735,...

  19. Bacteriophage remediation of bacterial pathogens in aquaculture: a review of the technology

    Science.gov (United States)

    Bacteriophages have been proposed as an alternative to antibiotic usage and several studies on their application in aquaculture have been reported. This review highlights progress to date on phage therapies for the following fish and shellfish diseases and associated pathogens: hemorrhagic septicem...

  20. Interaction of Pseudomonas putida ATCC 12633 and Bacteriophage gh-1 in Berea Sandstone Rock.

    Science.gov (United States)

    Chang, P L; Yen, T F

    1985-12-01

    Measurements of the passage of Pseudomonas putida ATCC 12633 and a phage-resistant mutant through Berea sandstone rock were made. When bacteriophage gh-1 was adsorbed within the rock matrix, a reduction in the passage of the susceptible but not the resistant cells through the rock was observed.

  1. Bacteriophage T4 genes sp and 40 apparently are the same.

    OpenAIRE

    Obringer, J; McCreary, P.; Bernstein, H

    1988-01-01

    The bacteriophage T4 spackle gene, which maintains host membrane integrity, mapped at the same position as gene 40 (head morphogenesis). The cloned spackle gene complemented and cross-reactivated a gene 40 mutant. Like the spackle mutant, gene 40 mutants were defective in genetic exclusion. Apparently, genes spackle and 40 are the same gene.

  2. Evolutionarily distinct bacteriophage endolysins featuring conserved peptidoglycan cleavage sites protect mice from MRSA infection

    Science.gov (United States)

    Staphylococcus aureus is a Gram-positive pathogen relevant for both human and animal health. With multi-drug resistant S. aureus strains becoming increasingly prevalent, alternative therapeutics are urgently needed. Bacteriophage endolysins (peptidoglycan hydrolases, PGH) are capable of killing Gra...

  3. Associations between Forkhead Box O1 (FoxO1 Expression and Indicators of Hepatic Glucose Production in Transition Dairy Cows Supplemented with Dietary Nicotinic Acid.

    Directory of Open Access Journals (Sweden)

    Asako Kinoshita

    Full Text Available Forkhead box protein O1 (FoxO1 is a transcription factor which promotes hepatic glucose production (HGP by up-regulating the transcription of gluconeogenic enzymes in monogastric species. The activity of FoxO1 is inhibited by insulin-induced phosphorylation. The aims of the present study were to find associations between FoxO1 expression and variables associated with HGP as affected by feeding regimen in dairy cows during the transition period. Twenty one healthy German Holstein cows were allocated to four groups (LC-CON, HC-CON, LC-NA with 5 cows/group and HC-NA with 6 cows/group, respectively. Cows received 0 (LC-CON and HC-CON or 24 (LC-NA and HC-NA g/d nicotinic acid with high (HC or low (LC concentrate proportion from -42 days (-41.8 + 4.8; mean + standard deviation relative to expected calving date (d-42 to d24. Liver biopsy was taken at d-42, 1, 21, and 100. The total protein expression of FoxO1 (tFoxO1 and the extent of phosphorylation of FoxO1 at serine 256 (pFoxO1 were analysed semiquantitatively by Western Blotting. The expression of hepatic mRNA of FoxO1 and seven genes associated with HGP was measured by real-time RT-PCR. Mixed model and Pearson's correlation were used for statistical evaluation with the level of significance at P<0.05. No dietary effect was observed either on feed intake, energy balance, or on the concentration of blood metabolites. Neither time nor diet affected the expression of FoxO1 total protein and mRNA. A NA × concentrate interaction was found in pFoxO1. However, no corresponding dietary effect was found in the mRNA expression of investigated genes. Different patterns of correlations between FoxO1-related variables and investigated indicators for HGP were found at d21 and 100. The results indicated that the regulation of HGP did not take place on the levels of mRNA and protein expression and the phosphorylation of FoxO1 in dairy cows in early lactation.

  4. STUDIES ON THE BACTERIOPHAGE OF D'HERELLE : VIII. THE MECHANISM OF LYSIS OF DEAD BACTERIA IN THE PRESENCE OF BACTERIOPHAGE.

    Science.gov (United States)

    Bronfenbrenner, J; Muckenfuss, R

    1927-04-30

    We have been able to confirm the observations of Twort as well as of Gratia, that dead staphylococcus may undergo lysis if, in addition to a suitable bacteriophage, there is also present live staphylococcus. Moreover, we have endeavored to ascertain the mechanism of this phenomenon and have found that in order to elicit it it is necessary to control the numbers of live and dead bacteria in the mixture. An excess of dead bacteria interferes with lysis by adsorbing the bacteriophage before it has the opportunity to initiate necessary changes in the live bacteria, so that all lysis is prevented. The phenomenon is specific, that is, the lysis of live bacteria is accompanied by lysis of dead bacteria of the same species only. Lysis of dead bacteria occurs best with staphylococcus, an organism which easily undergoes spontaneous autolysis under appropriate conditions. In the case of B. coli or B. dysenteriae the lysis of the dead bacteria is uncertain. Dead bacteria need not be present in the mixture at the beginning of the experiment; they will be dissolved if added any time before, during, or after the completion of lysis of live bacteria. If the test is performed so that a suitable semipermeable membrane is interposed between the dead and live bacteria, the dead bacteria are not dissolved, in spite of the lysis of live bacteria on the other side of the membrane. The agent determining the lysis of dead bacteria is not diffusible, while the principle initiating the lysis of live bacteria diffuses freely and is demonstrably present on both sides of the membrane. The complete independence of the agent causing dissolution of dead bacteria from bacteriophage can also be shown by separating the two agents by means of filtration, or by adsorption on bacteria. The ferment-like substance responsible for the lysis of dead bacteria is different from the bacteriophage. It is not diffusible through collodion, it is easily adsorbed on clay filters, it is heat-labile, and is

  5. 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.

  6. The bacteriophage ϕ29 tail possesses a pore-forming loop for cell membrane penetration.

    Science.gov (United States)

    Xu, Jingwei; Gui, Miao; Wang, Dianhong; Xiang, Ye

    2016-06-23

    Most bacteriophages are tailed bacteriophages with an isometric or a prolate head attached to a long contractile, long non-contractile, or short non-contractile tail. The tail is a complex machine that plays a central role in host cell recognition and attachment, cell wall and membrane penetration, and viral genome ejection. The mechanisms involved in the penetration of the inner host cell membrane by bacteriophage tails are not well understood. Here we describe structural and functional studies of the bacteriophage ϕ29 tail knob protein gene product 9 (gp9). The 2.0 Å crystal structure of gp9 shows that six gp9 molecules form a hexameric tube structure with six flexible hydrophobic loops blocking one end of the tube before DNA ejection. Sequence and structural analyses suggest that the loops in the tube could be membrane active. Further biochemical assays and electron microscopy structural analyses show that the six hydrophobic loops in the tube exit upon DNA ejection and form a channel that spans the lipid bilayer of the membrane and allows the release of the bacteriophage genomic DNA, suggesting that cell membrane penetration involves a pore-forming mechanism similar to that of certain non-enveloped eukaryotic viruses. A search of other phage tail proteins identified similar hydrophobic loops, which indicates that a common mechanism might be used for membrane penetration by prokaryotic viruses. These findings suggest that although prokaryotic and eukaryotic viruses use apparently very different mechanisms for infection, they have evolved similar mechanisms for breaching the cell membrane. PMID:27309813

  7. Photoreactivation of bacteriophages after UV disinfection: role of genome structure and impacts of UV source.

    Science.gov (United States)

    Rodriguez, Roberto A; Bounty, Sarah; Beck, Sara; Chan, Connie; McGuire, Christian; Linden, Karl G

    2014-05-15

    The UV inactivation kinetics of bacteriophages MS2, PhiX174, T1 and PRD1 and the potential of bacterial UV repair mechanisms to reactivate these bacteriophages is described here. The selected bacteriophages represent a range of genome size, single and double stranded genomes, circular and linear organization and RNA and DNA. Bacteriophages were exposed to UV irradiation from two different collimated beam UV irradiation sources (medium-pressure (MP) mercury lamps and low-pressure (LP) mercury lamps) and assayed during which host-phage cultures were exposed to photoreactivating light for 6 h, then incubated overnight at 37 °C in the dark. Dark controls following UV exposure were performed in parallel. UV inactivation kinetics (using dark controls) showed that circular ssDNA phage (PhiX174) was the most sensitive and linear ssRNA phage (MS2) was the more resistant phage. No photoreactivation was observed for MS2 (RNA phage) and the highest photoreactivation was observed for PRD1. In the case of PRD1, the dose required for 4-log reduction (dark control) was around 35 mJ/cm(2), with a similar dose observed for both UV sources (MP and LP). When the photoreactivation step was added, the dose required for 4-log reduction using LP lamps was 103 mJ/cm(2) and for MP lamps was 60 mJ/cm(2). Genome organization differences between bacteriophages play an important role in resistance to UV inactivation and potential photoreactivation mediated by bacterial host mechanisms. The use of photoreactivation during the assay of PRD1 creates a more conservative surrogate for potential use in UV challenge testing.

  8. Performance of viruses and bacteriophages for fecal source determination in a multi-laboratory, comparative study.

    Science.gov (United States)

    Harwood, Valerie J; Boehm, Alexandria B; Sassoubre, Lauren M; Vijayavel, Kannappan; Stewart, Jill R; Fong, Theng-Theng; Caprais, Marie-Paule; Converse, Reagan R; Diston, David; Ebdon, James; Fuhrman, Jed A; Gourmelon, Michele; Gentry-Shields, Jennifer; Griffith, John F; Kashian, Donna R; Noble, Rachel T; Taylor, Huw; Wicki, Melanie

    2013-11-15

    An inter-laboratory study of the accuracy of microbial source tracking (MST) methods was conducted using challenge fecal and sewage samples that were spiked into artificial freshwater and provided as unknowns (blind test samples) to the laboratories. The results of the Source Identification Protocol Project (SIPP) are presented in a series of papers that cover 41 MST methods. This contribution details the results of the virus and bacteriophage methods targeting human fecal or sewage contamination. Human viruses used as source identifiers included adenoviruses (HAdV), enteroviruses (EV), norovirus Groups I and II (NoVI and NoVII), and polyomaviruses (HPyVs). Bacteriophages were also employed, including somatic coliphages and F-specific RNA bacteriophages (FRNAPH) as general indicators of fecal contamination. Bacteriophage methods targeting human fecal sources included genotyping of FRNAPH isolates and plaque formation on bacterial hosts Enterococcus faecium MB-55, Bacteroides HB-73 and Bacteroides GB-124. The use of small sample volumes (≤50 ml) resulted in relatively insensitive theoretical limits of detection (10-50 gene copies or plaques × 50 ml(-1)) which, coupled with low virus concentrations in samples, resulted in high false-negative rates, low sensitivity, and low negative predictive values. On the other hand, the specificity of the human virus methods was generally close to 100% and positive predictive values were ∼40-70% with the exception of NoVs, which were not detected. The bacteriophage methods were generally much less specific toward human sewage than virus methods, although FRNAPH II genotyping was relatively successful, with 18% sensitivity and 85% specificity. While the specificity of the human virus methods engenders great confidence in a positive result, better concentration methods and larger sample volumes must be utilized for greater accuracy of negative results, i.e. the prediction that a human contamination source is absent.

  9. Control of Listeria monocytogenes growth in soft cheeses by bacteriophage P100

    Directory of Open Access Journals (Sweden)

    Elaine Nóbrega Gibson Silva

    2014-01-01

    Full Text Available The purpose of this study was to determine the effect of bacteriophage P100 on strains of Listeria monocytogenes in artificially inoculated soft cheeses. A mix of L. monocytogenes 1/2a and Scott A was inoculated in Minas Frescal and Coalho cheeses (approximately 10(5 cfu/g with the bacteriophage added thereafter (8.3 x 10(7 PFU/g. Samples were analyzed immediately, and then stored at 10 ºC for seven days. At time zero, 30 min post-infection, the bacteriophage P100 reduced L. monocytogenes counts by 2.3 log units in Minas Frescal cheese and by 2.1 log units in Coalho cheese, compared to controls without bacteriophage. However, in samples stored under refrigeration for seven days, the bacteriophage P100 was only weakly antilisterial, with the lowest decimal reduction (DR for the cheeses: 1.0 log unit for Minas Frescal and 0.8 log units for Coalho cheese. The treatment produced a statistically significant decrease in the counts of viable cells (p < 0.05 and in all assays performed, we observed an increase of approximately one log cycle in the number of viable cells of L. monocytogenes in the samples under refrigeration for seven days. Moreover, a smaller effect of phages was observed. These results, along with other published data, indicate that the effectiveness of the phage treatment depends on the initial concentration of L. monocytogenes, and that a high concentration of phages per unit area is required to ensure sustained inactivation of target pathogens on food surfaces.

  10. Prevalence and molecular characterization of Vibrio cholerae O1, non-O1 and non-O139 in tropical seafood in Cochin, India.

    Science.gov (United States)

    Kumar, Rakesh; Lalitha, Kuttannappilly V

    2013-03-01

    The objective of this study was to determine the prevalence of O1, O139, and non-O1 and non-O139 Vibrio cholerae, which were associated with fresh and raw seafood samples harvested from Cochin, India waters during 2009-2011. Results from V. cholerae-specific biochemical, molecular, and serological assays identified five El Tor V. cholerae O1 Ogawa strains and 377 non-O1, non-O139 V. cholerae strains from 265 seafood samples. V. cholerae O139 strains were not isolated. Polymerase chain reaction assays confirmed the presence of V. cholerae O1 El Tor biotype in seafood. Antibiotic susceptibility analysis revealed that the V. cholerae O1 strains were pansusceptible to 20 test antibiotics, whereas 26%, 40%, 62%, and 84% of the non-O1, non-O139 V. cholerae strains were resistant to cefpodoxime, ticarcillin, augmentin, and colistin, respectively. Detection of virulence and regulatory genes in V. cholerae associated with seafood revealed the presence of virulence and regulatory genes (i.e., ctx, zot, ace, toxR genes) in V. cholerae O1 strains, nevertheless, presence of ace and toxR genes were detected in non-O1, non-O139 in 9.8 and 91% strains, respectively. In conclusion, the presence of pathogenic V. cholerae in seafood harvested from local Cochin waters warrants the introduction of a postharvest seafood monitoring program, which will lead to a greater understanding of the distribution, abundance, and virulence of diverse pathogenic Vibrio populations that inhabit these different coastal regions so that a risk management program can be established.

  11. Associations between Forkhead Box O1 (FoxO1) Expression and Indicators of Hepatic Glucose Production in Transition Dairy Cows Supplemented with Dietary Nicotinic Acid.

    Science.gov (United States)

    Kinoshita, Asako; Locher, Lena; Tienken, Reka; Meyer, Ulrich; Dänicke, Sven; Rehage, Jürgen; Huber, Korinna

    2016-01-01

    Forkhead box protein O1 (FoxO1) is a transcription factor which promotes hepatic glucose production (HGP) by up-regulating the transcription of gluconeogenic enzymes in monogastric species. The activity of FoxO1 is inhibited by insulin-induced phosphorylation. The aims of the present study were to find associations between FoxO1 expression and variables associated with HGP as affected by feeding regimen in dairy cows during the transition period. Twenty one healthy German Holstein cows were allocated to four groups (LC-CON, HC-CON, LC-NA with 5 cows/group and HC-NA with 6 cows/group, respectively). Cows received 0 (LC-CON and HC-CON) or 24 (LC-NA and HC-NA) g/d nicotinic acid with high (HC) or low (LC) concentrate proportion from -42 days (-41.8 + 4.8; mean + standard deviation) relative to expected calving date (d-42) to d24. Liver biopsy was taken at d-42, 1, 21, and 100. The total protein expression of FoxO1 (tFoxO1) and the extent of phosphorylation of FoxO1 at serine 256 (pFoxO1) were analysed semiquantitatively by Western Blotting. The expression of hepatic mRNA of FoxO1 and seven genes associated with HGP was measured by real-time RT-PCR. Mixed model and Pearson's correlation were used for statistical evaluation with the level of significance at Pdairy cows in early lactation. PMID:26800252

  12. Survival of Vibrio cholerae O1 on fomites.

    Science.gov (United States)

    Farhana, Israt; Hossain, Zenat Zebin; Tulsiani, Suhella Mohan; Jensen, Peter Kjær Mackie; Begum, Anowara

    2016-09-01

    It is well established that the contamination sources of cholera causing bacteria, Vibrio cholerae, are water and food, but little is known about the transmission role of the fomites (surfaces that can carry pathogens) commonly used in households. In the absence of appropriate nutrients or growth conditions on fomites, bacteria have been known to assume a viable but non-culturable (VBNC) state after a given period of time. To investigate whether and when V. cholerae O1 assumes such a state, this study investigated the survival and viable quantification on a range of fomites such as paper, wood, glass, plastic, cloth and several types of metals under laboratory conditions. The fomites were inoculated with an outbreak strain of V. cholerae and its culturability was examined by drop plate count method at 30 min intervals for up to 6 h. For molecular detection, the viable/dead stain ethidium monoazide (EMA) which inhibits amplification of DNA from dead cells was used in combination with real-time polymerase chain reaction (EMA-qPCR) for direct quantitative analyses of viable V. cholerae at 2, 4, 6, 24 h and 7 day time intervals. Results showed that V. cholerae on glass and aluminum surfaces lost culturability within one hour after inoculation but remained culturable on cloth and wood for up to four hours. VBNC V. cholerae on dry fomite surfaces was detected and quantified by EMA-qPCR even 7 days after inoculation. In conclusion, the prolonged survival of V. cholerae on various household fomites may play vital role in cholera transmission and needs to be further investigated.

  13. Survival of Vibrio cholerae O1 on fomites.

    Science.gov (United States)

    Farhana, Israt; Hossain, Zenat Zebin; Tulsiani, Suhella Mohan; Jensen, Peter Kjær Mackie; Begum, Anowara

    2016-09-01

    It is well established that the contamination sources of cholera causing bacteria, Vibrio cholerae, are water and food, but little is known about the transmission role of the fomites (surfaces that can carry pathogens) commonly used in households. In the absence of appropriate nutrients or growth conditions on fomites, bacteria have been known to assume a viable but non-culturable (VBNC) state after a given period of time. To investigate whether and when V. cholerae O1 assumes such a state, this study investigated the survival and viable quantification on a range of fomites such as paper, wood, glass, plastic, cloth and several types of metals under laboratory conditions. The fomites were inoculated with an outbreak strain of V. cholerae and its culturability was examined by drop plate count method at 30 min intervals for up to 6 h. For molecular detection, the viable/dead stain ethidium monoazide (EMA) which inhibits amplification of DNA from dead cells was used in combination with real-time polymerase chain reaction (EMA-qPCR) for direct quantitative analyses of viable V. cholerae at 2, 4, 6, 24 h and 7 day time intervals. Results showed that V. cholerae on glass and aluminum surfaces lost culturability within one hour after inoculation but remained culturable on cloth and wood for up to four hours. VBNC V. cholerae on dry fomite surfaces was detected and quantified by EMA-qPCR even 7 days after inoculation. In conclusion, the prolonged survival of V. cholerae on various household fomites may play vital role in cholera transmission and needs to be further investigated. PMID:27430513

  14. Single molecule studies of DNA packaging by bacteriophages

    Science.gov (United States)

    Fuller, Derek Nathan

    The DNA packaging dynamics of bacteriophages φ29, gamma, and T4 were studied at the single molecule level using a dual trap optical tweezers. Also, a method for producing long DNA molecules by PCR for optical tweezers studies of protein DNA interactions is presented and thoroughly characterized. This DNA preparation technique provided DNA samples for the φ29 and T4 studies. In the studies of φ29, the role of charge was investigated by varying the ionic conditions of the packaging buffer. Ionic conditions in which the DNA charge was highly screened due to divalent and trivalent cations showed the lowest resistance to packaging of the DNA to high density. This confirmed the importance of counterions in shielding the DNA interstrand repulsion when packaged to high density. While the ionic nature of the packaging buffer had a strong effect on packaging velocities, there was no clear trend between the counterion-screened charge of the DNA and the maximum packaging velocity. The packaging studies of lambda and T4 served as systems for comparative studies with φ29. Each system showed similarities to the φ29 system and unique differences. Both the lambda and T4 packaging motors were capable of generating forces in excess of 50 pN and showed remarkably high processivity, similar to φ29. However, dynamic structural transitions were observed with lambda that are not observed with φ29. The packaging of the lambda genome showed capsid expansion at approximately 30 percent of the genome packaged and capsid rupture at 90 percent of the genome packaged in the absence of capsid stabilizing protein gpD. Unique to the T4 packaging motor, packaging dynamics showed a remarkable amount of variability in velocities. This variability was seen both within individual packaging phages and from one phage to the next. This is possibly due to different conformational states of the packaging machinery. Additionally, lambda and T4 had average packaging velocities under minimal load of 600

  15. Antistaphylococcal activity of bacteriophage derived chimeric protein P128

    Directory of Open Access Journals (Sweden)

    Vipra Aradhana A

    2012-03-01

    Full Text Available Abstract Background Bacterial drug resistance is one of the most significant challenges to human health today. In particular, effective antibacterial agents against methicillin-resistant Staphylococcus aureus (MRSA are urgently needed. A causal relationship between nasal commensal S. aureus and infection has been reported. Accordingly, elimination of nasal S. aureus reduces the risk of infection. Enzymes that degrade bacterial cell walls show promise as antibacterial agents. Bacteriophage-encoded bacterial cell wall-degrading enzymes exhibit intrinsic bactericidal activity. P128 is a chimeric protein that combines the lethal activity of the phage tail-associated muralytic enzyme of Phage K and the staphylococcal cell wall targeting-domain (SH3b of lysostaphin. Here we report results of in vitro studies evaluating the susceptibility of staphylococcal strains to this novel protein. Results Using the broth microdilution method adapted for lysostaphin, we found that P128 is effective against S. aureus clinical strains including MRSA, methicillin-sensitive S. aureus (MSSA, and a mupirocin-resistant S. aureus. Minimum bactericidal concentrations and minimum inhibitory concentrations of P128 (1-64 μg/mL were similar across the 32 S. aureus strains tested, demonstrating its bactericidal nature. In time-kill assays, P128 reduced colony-forming units by 99.99% within 1 h and inhibited growth up to 24 h. In an assay simulating topical application of P128 to skin or other biological surfaces, P128 hydrogel was efficacious when layered on cells seeded on solid media. P128 hydrogel was lethal to Staphylococci recovered from nares of healthy people and treated without any processing or culturing steps, indicating its in situ efficacy. This methodology used for in vitro assessment of P128 as an agent for eradicating nasal carriage is unique. Conclusions The novel chimeric protein P128 is a staphylococcal cell wall-degrading enzyme under development for

  16. Associations between Forkhead Box O1 (FoxO1) Expression and Indicators of Hepatic Glucose Production in Transition Dairy Cows Supplemented with Dietary Nicotinic Acid.

    Science.gov (United States)

    Kinoshita, Asako; Locher, Lena; Tienken, Reka; Meyer, Ulrich; Dänicke, Sven; Rehage, Jürgen; Huber, Korinna

    2016-01-01

    Forkhead box protein O1 (FoxO1) is a transcription factor which promotes hepatic glucose production (HGP) by up-regulating the transcription of gluconeogenic enzymes in monogastric species. The activity of FoxO1 is inhibited by insulin-induced phosphorylation. The aims of the present study were to find associations between FoxO1 expression and variables associated with HGP as affected by feeding regimen in dairy cows during the transition period. Twenty one healthy German Holstein cows were allocated to four groups (LC-CON, HC-CON, LC-NA with 5 cows/group and HC-NA with 6 cows/group, respectively). Cows received 0 (LC-CON and HC-CON) or 24 (LC-NA and HC-NA) g/d nicotinic acid with high (HC) or low (LC) concentrate proportion from -42 days (-41.8 + 4.8; mean + standard deviation) relative to expected calving date (d-42) to d24. Liver biopsy was taken at d-42, 1, 21, and 100. The total protein expression of FoxO1 (tFoxO1) and the extent of phosphorylation of FoxO1 at serine 256 (pFoxO1) were analysed semiquantitatively by Western Blotting. The expression of hepatic mRNA of FoxO1 and seven genes associated with HGP was measured by real-time RT-PCR. Mixed model and Pearson's correlation were used for statistical evaluation with the level of significance at Pprotein and mRNA. A NA × concentrate interaction was found in pFoxO1. However, no corresponding dietary effect was found in the mRNA expression of investigated genes. Different patterns of correlations between FoxO1-related variables and investigated indicators for HGP were found at d21 and 100. The results indicated that the regulation of HGP did not take place on the levels of mRNA and protein expression and the phosphorylation of FoxO1 in dairy cows in early lactation.

  17. The evaluation of hollow-fiber ultrafiltration and celite concentration of enteroviruses, adenoviruses and bacteriophage from different water matrices

    Data.gov (United States)

    U.S. Environmental Protection Agency — The data to support the evaluation of hollow-fiber ultrafiltration and celite concentration of enteroviruses, adenoviruses and bacteriophage from different water...

  18. Droplet optofluidic imaging for λ-bacteriophage detection via co-culture with host cell Escherichia coli.

    Science.gov (United States)

    Yu, J Q; Huang, W; Chin, L K; Lei, L; Lin, Z P; Ser, W; Chen, H; Ayi, T C; Yap, P H; Chen, C H; Liu, A Q

    2014-09-21

    Bacteriophages are considered as attractive indicators for determining drinking water quality since its concentration is strongly correlated with virus concentrations in water samples. Previously, bacteriophage detection was based on a plague assay that required a complicated labelling technique and a time-consuming culture assay. Here, for the first time, a label-free bacteriophage detection is reported by using droplet optofluidic imaging, which uses host-cell-containing microdroplets as reaction carriers for bacteriophage infection due to a higher contact ratio. The optofluidic imaging is based on the effective refractive index changes in the microdroplet correlated with the growth rate of the infected host cells, which is highly sensitive, i.e. can detect one E. coli cell. The droplet optofluidic system is not only used in drinking water quality monitoring, but also has high potential applications for pathogenic bacteria detection in clinical diagnosis and food industry.

  19. Characterization of FP22, a large streptomycete bacteriophage with DNA insensitive to cleavage by many restriction enzymes.

    Science.gov (United States)

    Hahn, D R; McHenney, M A; Baltz, R H

    1990-12-01

    Bacteriophage FP22 has a very broad host range within streptomycetes and appeared to form lysogens of Streptomyces ambofaciens ATCC 15154. FP22 shared strong cross-immunity and antibody cross-reactivity with bacteriophage P23, but not with seven other streptomycete bacteriophages. FP22 particles had a head diameter of 71 nm and a tail length of 307 nm. The FP22 genome was 131 kb, which is the largest bacteriophage genome reported for streptomycetes. The G + C content of the genome was 46 mol% and restriction mapping indicated that FP22 DNA had discrete ends. NaCl- and pyrophosphate-resistant deletion mutants were readily isolated and the extent of the deletions defined at least 23 kb of dispensable DNA in two regions of the genome. The DNA was not cleaved by most restriction endonucleases (or isoschizomers) which have been identified in the streptomycetes, including the tetranucleotide cutter MboI (GATC).

  20. Comparative genomics of four closely related Clostridium perfringens bacteriophages reveals variable rates of evolution within a core genome

    Science.gov (United States)

    Background: Biotechnological uses of bacteriophage gene products as alternatives to conventional antibiotics will require a thorough understanding of their genomic context. We sequenced and analyzed the genomes of four closely related phages isolated from Clostridium perfringens, an important agricu...

  1. IMPORTANCE OF THE DYNAMICS OF BACTERIOPHAGE-HOST INTERACTIONS TO BACTERIAL ABUNDANCE AND GENETIC DIVERSITY IN AQUATIC ENVIRONMENTS (RESEARCH BRIEF)

    Science.gov (United States)

    Using Pseudomonas aeruginosa and its bacteriophages as a model system, we have clearly demonstrated a significant potential for viral-mediated gene transfer (transduction) of both plasmid and chromosomal DNA in freshwater microbial populations. These investigations have predicted...

  2. STUDIES ON THE BACTERIOPHAGE OF D'HERELLE : IX. EVIDENCE OF HYDROLYSIS OF BACTERIAL PROTEIN DURING LYSIS.

    Science.gov (United States)

    Hetler, D M; Bronfenbrenner, J

    1928-07-31

    1. During the process of lysis by bacteriophage, there is an appreciable increase in the amount of free amino acid present in the culture. 2. The increase of free amino acid is due to hydrolysis of bacterial protein.

  3. Application of zinc chloride precipitation method for rapid isolation and concentration of infectious Pectobacterium spp. and Dickeya spp. lytic bacteriophages from surface water and plant and soil extracts.

    Science.gov (United States)

    Czajkowski, Robert; Ozymko, Zofia; Lojkowska, Ewa

    2016-01-01

    This is the first report describing precipitation of bacteriophage particles with zinc chloride as a method of choice to isolate infectious lytic bacteriophages against Pectobacterium spp. and Dickeya spp. from environmental samples. The isolated bacteriophages are ready to use to study various (ecological) aspects of bacteria-bacteriophage interactions. The method comprises the well-known precipitation of phages from aqueous extracts of the test material by addition of ZnCl2, resuscitation of bacteriophage particles in Ringer's buffer to remove the ZnCl2 excess and a soft agar overlay assay with the host bacterium to isolate infectious individual phage plaques. The method requires neither an enrichment step nor other steps (e. g., PEG precipitation, ultrafiltration, or ultracentrifugation) commonly used in other procedures and results in isolation of active viable bacteriophage particles.

  4. Comparative (Meta)genomic Analysis and Ecological Profiling of Human Gut-Specific Bacteriophage φB124-14

    OpenAIRE

    Ogilvie, Lesley A.; Caplin, Jonathan; Dedi, Cinzia; Diston, David; Cheek, Elizabeth; Bowler, Lucas; Taylor, Huw; Ebdon, James; Jones, Brian V.

    2012-01-01

    Bacteriophage associated with the human gut microbiome are likely to have an important impact on community structure and function, and provide a wealth of biotechnological opportunities. Despite this, knowledge of the ecology and composition of bacteriophage in the gut bacterial community remains poor, with few well characterized gut-associated phage genomes currently available. Here we describe the identification and in-depth (meta)genomic, proteomic, and ecological analysis of a human gut-s...

  5. Biological Properties and Cell Tropism of Chp2, a Bacteriophage of the Obligate Intracellular Bacterium Chlamydophila abortus

    OpenAIRE

    Everson, J. S.; Garner, S. A.; Fane, B.; Liu, B.-L.; Lambden, P R; Clarke, I N

    2002-01-01

    A number of bacteriophages belonging to the Microviridae have been described infecting chlamydiae. Phylogenetic studies divide the Chlamydiaceae into two distinct genera, Chlamydia and Chlamydophila, containing three and six different species, respectively. In this work we investigated the biological properties and host range of the recently described bacteriophage Chp2 that was originally discovered in Chlamydophila abortus. The obligate intracellular development cycle of chlamydiae has prec...

  6. Monitoring water sources for environmental reservoirs of toxigenic Vibrio cholerae O1, Haiti.

    Science.gov (United States)

    Alam, Meer T; Weppelmann, Thomas A; Weber, Chad D; Johnson, Judith A; Rashid, Mohammad H; Birch, Catherine S; Brumback, Babette A; Beau de Rochars, Valery E Madsen; Morris, J Glenn; Ali, Afsar

    2014-03-01

    An epidemic of cholera infections was documented in Haiti for the first time in more than 100 years during October 2010. Cases have continued to occur, raising the question of whether the microorganism has established environmental reservoirs in Haiti. We monitored 14 environmental sites near the towns of Gressier and Leogane during April 2012-March 2013. Toxigenic Vibrio cholerae O1 El Tor biotype strains were isolated from 3 (1.7%) of 179 water samples; nontoxigenic O1 V. cholerae was isolated from an additional 3 samples. All samples containing V. cholerae O1 also contained non-O1 V. cholerae. V. cholerae O1 was isolated only when water temperatures were ≥31°C. Our data substantiate the presence of toxigenic V. cholerae O1 in the aquatic environment in Haiti. These isolations may reflect establishment of long-term environmental reservoirs in Haiti, which may complicate eradication of cholera from this coastal country.

  7. Purification and characterization of pili of a Vibrio cholerae non-O1 strain.

    OpenAIRE

    Yamashiro, T.; Nakasone, N; Iwanaga, M

    1993-01-01

    Pili of the Vibrio cholerae non-O1 strain V10 were purified and characterized. The V10 pili were physicochemically and immunologically different from those of the previously reported V. cholerae non-O1 strain S7, although the pili of the two strains had homologous N-terminal amino acid sequences. V10 plus antigen was detected only in V. cholerae non-O1 strains.

  8. Inactivation of F-specific bacteriophages during flocculation with polyaluminum chloride - a mechanistic study.

    Science.gov (United States)

    Kreißel, Katja; Bösl, Monika; Hügler, Michael; Lipp, Pia; Franzreb, Matthias; Hambsch, Beate

    2014-03-15

    Bacteriophages are often used as surrogates for enteric viruses in spiking experiments to determine the efficiencies of virus removal of certain water treatment measures, like e.g. flocculation or filtration steps. Such spiking experiments with bacteriophages are indispensable if the natural virus concentrations in the raw water of water treatment plants are too low to allow the determination of elimination levels over several orders of magnitude. In order to obtain reliable results from such spiking tests, it is essential that bacteriophages behave comparable to viruses and remain stable during the experiments. To test this, the influence of flocculation parameters on the bacteriophages MS2, Qβ and phiX174 was examined. Notably, the F-specific phages MS2 and Qβ were found to be inactivated in flocculation processes with polyaluminum chloride (PACl). In contrast, other aluminum coagulants like AlCl3 or Al2(SO4)3 did not show a comparable effect on MS2 in this study. In experiments testing the influence of different PACl species on MS2 and Qβ inactivation during flocculation, it could be shown that cationic dissolved PACl species (Al13) interacted with the MS2 surface and hereby reduced the surviving phage fraction to c/c0 values below 1*10(-4) even at very low PACl concentrations of 7 μmol Al/L. Other inactivation mechanisms like the irreversible adsorption of phages to the floc structure or the damage of phage surfaces due to entrapment into the floc during coagulation and floc formation do not seem to contribute to the low surviving fraction found for both F-specific bacteriophages. Furthermore, no influence of phage agglomeration or pH drops during the flocculation process on phage inactivation could be observed. The somatic coliphage phiX174 in contrast did not show sensitivity to chemical stress and in accordance only slight interaction between Al13 and the phage surface was observed. Consequently, F-specific phages like MS2 should not be used as

  9. Interaction between bacteriophage and pyrophyllite clay in aqueous solution

    Science.gov (United States)

    Park, Jeong-Ann; Kim, Jae-Hyun; Kang, Jin-Kyu; Son, Jeong-Woo; Yi, In-Geol; Kim, Song-Bae

    2014-05-01

    Viral contamination results in a degradation in drinking water quality and a threat to public health. Toprovide safe drinking water, water treatment alternatives using various adsorbents and filter media such as activated carbon, bituminous coal, quartz sand and clay have been considered. Pyrophyllite is a 2:1 clay mineral having dioctahedral layer structure with octahedrally coordinated Al ion sheets between two sheets of SiO4 tetrahedra. It is a hydrous aluminosilicate clay with the chemical composition AlSi2O5(OH). Pyrophyllite has recently been investigated as a potential low-cost and environmental friendly adsorbent for removing various contaminants. The aim of this study was to investigate the removal of the bacteriophage MS2 from aqueous solution using pyrophyllite. Batch experiments were conducted to examine the MS2 sorption to pyrophyllite. The influence of fluoride, a groundwater contaminant, on the removal of MS2 was also observed. Batch results demonstrated that pyrophyllite was effective in MS2 removal. The percent removal increased from 5.26% to 99.99% (= 4.0 log removal) as the pyrophyllite concentrations increased from 0.2 to 20 g/L. More than 99% of MS2 could be removed with a pyrophyllite concentration of ≥ 4 g/L. The sorption of MS2 to pyrophyllite was rapid. Within 15 min, approximately 99.98% (= 3.7 log removal) of MS2 was attained. More than 4.0 log removal was achieved after 180 min. The experimental data were analyzed with the pseudo first-order and pseudo second-order kinetic models. The correlation coefficient showed that pseudo second-order model was better than pseudo first-order model at describing the kinetic data. The amount of MS2 removed at equilibrium was determined to be 1.43 × 108 pfu/g from the pseudo second-order model. The experimental data were also analyzed with the Freundlich and Langmuir isotherm models. The correlation coefficients showed that the Langmuir model was more suitable than the Freundlich model for MS2

  10. Growth of Vibrio cholerae O1 Ogawa Eltor in freshwater.

    Science.gov (United States)

    Vital, Marius; Füchslin, Hans Peter; Hammes, Frederik; Egli, Thomas

    2007-07-01

    Growth of Vibrio cholerae O1 Ogawa Eltor was studied with a growth assay in which autoclaved and filtered (0.22 microm) freshwater was inoculated at low cell density (5 x 10(3) cells ml(-1)) and proliferation was followed with flow cytometry. Against the common view, V. cholerae was able to grow extensively in different kinds of freshwater. The bacterium multiplied in river water, lake water and effluent of a wastewater treatment plant up to a cell density of 1.55 x 10(6) cells ml(-1). In these samples, apparent assimilable organic carbon (AOC(app)) concentrations ranged from 52 up to 800 microg l(-1) and the results demonstrate a positive trend between the AOC(app) concentration and final cell concentration, suggesting that AOC was a key parameter governing growth of V. cholerae. No growth was observed in waters (tap and bottled drinking water) containing less than approximately 60 microg AOC(app) l(-1). When pure cultures of V. cholerae were grown on identical lake water at different temperatures (20, 25 and 30 degrees C) the maximum specific growth rates (micromax) achieved were 0.22 h(-1), 0.32 h(-1) and 0.45 h(-1), respectively. In addition, growth was characterized in lake water samples amended with different concentrations of NaCl. The highest micromax of V. cholerae was recorded at moderate salinity levels (5 g NaCl l(-1), micromax=0.84 h(-1)), whereas at 30 g NaCl l(-1) (micromax=0.30 h(-1)) or 0 g NaCl l(-1) (micromax)=0.40 h(-1)) specific growth rates were significantly reduced. In the water tested here, micro(max) of V. cholerae was always around 50 % of that exhibited by a freshwater community of indigenous bacteria enriched from the water sampling site. Direct batch competition experiments between V. cholerae and the lake water bacterial community were performed at different temperatures in which V. cholerae was enumerated in the total community using fluorescent-surface antibodies. In all cases V. cholerae was able to grow and constituted around 10

  11. Thermodynamic Database for the NdO(1.5)-YO(1.5)-YbO(1.5)-ScO(1.5)-ZrO2 System

    Science.gov (United States)

    Jacobson, Nathan S.; Copland, Evan H.; Kaufman, Larry

    2001-01-01

    A database for YO(1.5)-NdO(1.5)-YbO(1.5)-ScO(1.5)-ZrO2 for ThermoCalc (ThermoCalc AB, Stockholm, Sweden) has been developed. The basis of this work is the YO(1.5)-ZrO2 assessment by Y. Du, Z. Jin, and P. Huang, 'Thermodynamic Assessment of the ZrO2-YO(1.5) System'. Experimentally only the YO(1.5)-ZrO2 system has been well-studied. All other systems are only approximately known. The major simplification in this work is the treatment of each single cation unit as a component. The pure liquid oxides are taken as reference states and two term lattice stability descriptions are used for each of the components. The limited experimental phase diagrams are reproduced.

  12. Cloning, sequencing, and recombinational analysis with bacteriophage BF23 of the bacteriophage T5 oad gene encoding the receptor-binding protein.

    OpenAIRE

    Krauel, V; Heller, K J

    1991-01-01

    Binding of bacteriophage T5 to its receptor, the Escherichia coli FhuA protein, is mediated by tail protein pb5. In this article we confirm that pb5 is encoded by the T5 oad gene and describe the isolation, expression, and sequencing of this gene. In order to locate oad precisely, we analyzed recombinants between BF23, a T5-related phage with a different host range, and plasmid clones containing segments of the T5 chromosome. This analysis also showed that oad has little or no homology with h...

  13. Impairment of Temperate Bacteriophage Adsorption by Brief Treatment of Escherichia coli with Dilute Solutions of Ethylenediaminetetraacetate

    Science.gov (United States)

    Protass, Jay J.; Korn, David

    1966-01-01

    Protass, Jay J. (National Institute of Arthritis and Metabolic Diseases, Bethesda, Md.), and David Korn. Impairment of temperate bacteriophage adsorption by brief treatment of Escherichia coli with dilute solutions of ethylenediaminetetraacetate. J. Bacteriol. 91:143–147. 1966.—Cells of Escherichia coli K-12 treated for 2 min with 2 × 10−4m ethylenediaminetetraacetate (EDTA) are unable to adsorb the temperate bacteriophages λvir and 434 but show no impairment of their ability to adsorb T-even phages or T5. This finding is consistent with the hypothesis that there are basic structural differences between the cell-wall receptors involved in the adsorption of the temperate and T classes of coliphages. PMID:16562097

  14. Interaction of packaging motor with the polymerase complex of dsRNA bacteriophage

    International Nuclear Information System (INIS)

    Many viruses employ molecular motors to package their genomes into preformed empty capsids (procapsids). In dsRNA bacteriophages the packaging motor is a hexameric ATPase P4, which is an integral part of the multisubunit procapsid. Structural and biochemical studies revealed a plausible RNA-translocation mechanism for the isolated hexamer. However, little is known about the structure and regulation of the hexamer within the procapsid. Here we use hydrogen-deuterium exchange and mass spectrometry to delineate the interactions of the P4 hexamer with the bacteriophage phi12 procapsid. P4 associates with the procapsid via its C-terminal face. The interactions also stabilize subunit interfaces within the hexamer. The conformation of the virus-bound hexamer is more stable than the hexamer in solution, which is prone to spontaneous ring openings. We propose that the stabilization within the viral capsid increases the packaging processivity and confers selectivity during RNA loading

  15. Cloning and expression of autogenes encoding RNA polymerases of T7-like bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Studier, F. William (Stony Brook, NY); Dubendorff, John W. (Sound Beach, NY)

    1998-01-01

    This invention relates to the cloning and expression of autogenes encoding RNA polymerases of T7 and T7-like bacteriophages, in which the RNA polymerase gene is transcribed from a promoter which is recognized by the encoded RNA polymerase. Cloning of T7 autogenes was achieved by reducing the activity of the RNA polymerase sufficiently to permit host cell growth. T7 RNA polymerase activity was controlled by combining two independent methods: lac-repression of the recombinant lac operator-T7 promoter in the autogene and inhibition of the polymerase by T7 lysozyme. Expression systems for producing the RNA polymerases of T7 and other T7-like bacteriophages, and expression systems for producing selected gene products are described, as well as other related materials and methods.

  16. Bacteriophages as viral indicators for radiation processing of water: a chemical approach

    Energy Technology Data Exchange (ETDEWEB)

    Gehringer, Peter E-mail: peter.gehringer@arcs.ac.at; Eschweiler, Helmut; Leth, Hermann; Pribil, Walter; Pfleger, Silvia; Cabaj, Alexander; Haider, Thomas; Sommer, Regina

    2003-06-01

    Inactivation of the bacteriophages PHI X 174 (somatic coliphage), MS2 (F-specific coliphage) and B40-8 (phage infecting Bacteroides fragilis) suspended in tap water was studied applying gamma and electron beam irradiation as well. PHI X 174 phage was found to be a suitable viral indicator for water disinfection by means of ionizing radiation. The nutrient broths introduced simultaneously with the bacteriophages into the water when it is spiked with the phages for the experiments did not significantly change the scavenging capacity of the water matrix. No dose rate effect was observed with MS2 and B40-8 phages but PHI X 174 phage showed a clear dose rate effect. It was found that in water MS2 phage is significantly more sensitive to ionizing radiation than Escherichia coli.

  17. Production and Purification of Recombinant Filamentous Bacteriophages Displaying Immunogenic Heterologous Epitopes.

    Science.gov (United States)

    Deng, Lei; Linero, Florencia; Saelens, Xavier

    2016-01-01

    Viruslike particles often combine high physical stability with robust immunogenicity. Furthermore, when such particles are based on bacteriophages, they can be produced in high amounts at minimal cost and typically will require only standard biologically contained facilities. We provide protocols for the characterization and purification of recombinant viruslike particles derived from filamentous bacteriophages. As an example, we focus on filamentous Escherichia coli fd phage displaying a conserved influenza A virus epitope that is fused genetically to the N-terminus of the major coat protein of this phage. A step-by-step procedure to obtain a high-titer, pure recombinant phage preparation is provided. We also describe a quality control experiment based on a biological readout of the purified fd phage preparation. These protocols together with the highlighted critical steps may facilitate generic implementation of the provided procedures for the display of other epitopes by recombinant fd phages.

  18. Cloning and expression of autogenes encoding RNA poly,erases of T7-like bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Studier, F. William (Stony Brook, NY); Dubendorff, John W. (Sound Beach, NY)

    1998-01-01

    This invention relates to the cloning and expression of autogenes encoding RNA polymerases of T7 and T7-like bacteriophages, in which the RNA polymerase gene is transcribed from a promoter which is recognized by the encoded RNA polymerase. Cloning of T7 autogenes was achieved by reducing the activity of the RNA polymerase sufficiently to permit host cell growth. T7 RNA polymerase activity was controlled by combining two independent methods: lac-repression of the recombinant lac operator-T7 promoter in the autogene and inhibition of the polymerase by T7 lysozyme. Expression systems for producing the RNA polymerases of T7 and other T7-like bacteriophages, and expression systems for producing selected gene products are described, as well as other related materials and methods.

  19. Study of the transfer RNAs coded by T2, T4, and T6 bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Desai, S.M.; Weiss, S.B.

    1977-07-25

    T2,T4, and T6 bacteriophage tRNAs coding for arginine, leucine, proline, isoleucine, and glycine were isolated under conditions of short term and long term infection of Escherchia coli B cells. The corresponding phage tRNA species were examined for sequence homology by RNA.DNA hybridization analysis and by their relative behavior on reversed phase chromatography. The results indicate that all three T-even phages code for similar tRNA species; however, some tRNA species are homologous, others are not, and not all of the same tRNA species are coded by each bacteriophage. Reversed phase chromatography showed the presence of isoacceptor tRNAs for each phage aminoacyl-tRNA species. Pulse-chase experiments for (/sup 32/P)tRNA/sup Gly/ suggest that the multiple isoacceptor species observed derive from the intracellular modification of a single tRNA/sup Gly/ gene product.

  20. Cloning and expression of autogenes encoding RNA polymerases of T7-like bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Studier, F.W.; Dubendorff, J.W.

    1998-10-20

    This invention relates to the cloning and expression of autogenes encoding RNA polymerases of T7 and T7-like bacteriophages, in which the RNA polymerase gene is transcribed from a promoter which is recognized by the encoded RNA polymerase. Cloning of T7 autogenes was achieved by reducing the activity of the RNA polymerase sufficiently to permit host cell growth. T7 RNA polymerase activity was controlled by combining two independent methods: lac-repression of the recombinant lac operator-T7 promoter in the autogene and inhibition of the polymerase by T7 lysozyme. Expression systems for producing the RNA polymerases of T7 and other T7-like bacteriophages, and expression systems for producing selected gene products are described, as well as other related materials and methods. 12 figs.

  1. Cloning and expression of autogenes encoding RNA polymerases of T7-like bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Studier, F.W.; Dubendorff, J.W.

    1998-11-03

    This invention relates to the cloning and expression of autogenes encoding RNA polymerases of T7 and T7-like bacteriophages, in which the RNA polymerase gene is transcribed from a promoter which is recognized by the encoded RNA polymerase. Cloning of T7 autogenes was achieved by reducing the activity of the RNA polymerase sufficiently to permit host cell growth. T7 RNA polymerase activity was controlled by combining two independent methods: lac-repression of the recombinant lac operator-T7 promoter in the autogene and inhibition of the polymerase by T7 lysozyme. Expression systems for producing the RNA polymerases of T7 and other T7-like bacteriophages, and expression systems for producing selected gene products are described, as well as other related materials and methods. 12 figs.

  2. Surface plasmon resonance detection of E. coli and methicillin-resistant S. aureus using bacteriophages.

    Science.gov (United States)

    Tawil, Nancy; Sacher, Edward; Mandeville, Rosemonde; Meunier, Michel

    2012-01-01

    Early diagnosis and appropriate treatment of Escherichia coli (E. coli) O157:H7 and methicillin-resistant Staphylococcus aureus (MRSA) are key elements in preventing resultant life-threatening illnesses, such as hemorrhagic colitis, hemolytic uremic syndrome, and septicemia. In this report, we describe the use of surface plasmon resonance (SPR) for the biodetection of pathogenic bacteria, using bacteriophages as the recognition elements. T4 bacteriophages were used to detect E. coli, while a novel, highly specific phage was used to detect MRSA. We found that the system permits label-free, real-time, specific, rapid and cost-effective detection of pathogens, for concentrations of 10(3) colony forming units/milliliter, in less than 20 min. This system promises to become a diagnostic tool for bacteria that cause major public concern for food safety, bioterrorism, and nosocomial infections.

  3. Streptomyces lipmanii expresses two restriction systems that inhibit plasmid transformation and bacteriophage plaque formation.

    Science.gov (United States)

    Matsushima, P; Baltz, R H

    1989-06-01

    Bacteriophage host range studies suggested that several beta-lactam-producing streptomycetes express similar restriction-modification systems. Streptomyces lipmanii LE32 expressed two restriction-modification systems, designated SliI and SliII. A mutant strain, PM87, was defective only in SliI restriction but expressed both SliI and SliII modification. Streptomyces sp. strain A57986, a natural isolate partially deficient in the expression of SliI and SliII restriction, nevertheless modified bacteriophage DNA for both SliI and SliII specificities. Protoplasts of PM87 and A57986 were transformed by several plasmids, and the modified plasmids isolated from these strains transformed wild-type S. lipmanii efficiently.

  4. Isolation and characterization of bacteriophages infecting nocardioforms in wastewater treatment plant.

    Science.gov (United States)

    Khairnar, Krishna; Pal, Preeti; Chandekar, Rajshree H; Paunikar, Waman N

    2014-01-01

    Activated sludge plants (ASP) are associated with the stable foaming problem worldwide. Apart from the physical and chemical treatment methods, biological treatment method has been least explored and may prove to be a novel and ecofriendly approach to tackle the problem of stable foam formation. In ASP Nocardia species are commonly found and are one of the major causes for forming sticky and stable foam. This study describes the isolation and characterization of three Nocardia bacteriophages NOC1, NOC2, and NOC3 for the control of Nocardia species. The bacteriophages isolated in this study have shown promising results in controlling foam producing bacterial growth under laboratory conditions, suggesting that it may prove useful in the field as an alternative biocontrol agent to reduce the foaming problem. To the best of our knowledge to date no work has been published from India related to biological approach for the control of foaming. PMID:25140256

  5. Isolation and Characterization of Bacteriophages Infecting Nocardioforms in Wastewater Treatment Plant

    Directory of Open Access Journals (Sweden)

    Krishna Khairnar

    2014-01-01

    Full Text Available Activated sludge plants (ASP are associated with the stable foaming problem worldwide. Apart from the physical and chemical treatment methods, biological treatment method has been least explored and may prove to be a novel and ecofriendly approach to tackle the problem of stable foam formation. In ASP Nocardia species are commonly found and are one of the major causes for forming sticky and stable foam. This study describes the isolation and characterization of three Nocardia bacteriophages NOC1, NOC2, and NOC3 for the control of Nocardia species. The bacteriophages isolated in this study have shown promising results in controlling foam producing bacterial growth under laboratory conditions, suggesting that it may prove useful in the field as an alternative biocontrol agent to reduce the foaming problem. To the best of our knowledge to date no work has been published from India related to biological approach for the control of foaming.

  6. Visualization of bacteriophage P1 infection by cryo-electron tomography of tiny Escherichia coli

    International Nuclear Information System (INIS)

    Bacteriophage P1 has a contractile tail that targets the conserved lipopolysaccharide on the outer membrane surface of the host for initial adsorption. The mechanism by which P1 DNA enters the host cell is not well understood, mainly because the transient molecular interactions between bacteriophage and bacteria have been difficult to study by conventional approaches. Here, we engineered tiny E. coli host cells so that the initial stages of P1-host interactions could be captured in unprecedented detail by cryo-electron tomography. Analysis of three-dimensional reconstructions of frozen-hydrated specimens revealed three predominant configurations: an extended tail stage with DNA present in the phage head, a contracted tail stage with DNA, and a contracted tail stage without DNA. Comparative analysis of various conformations indicated that there is uniform penetration of the inner tail tube into the E. coli periplasm and a significant movement of the baseplate away from the outer membrane during tail contraction.

  7. Bacteriophage amplification assay for detection of Listeria spp. using virucidal laser treatment

    Directory of Open Access Journals (Sweden)

    I.C. Oliveira

    2012-09-01

    Full Text Available A protocol for the bacteriophage amplification technique was developed for quantitative detection of viable Listeria monocytogenes cells using the A511 listeriophage with plaque formation as the end-point assay. Laser and toluidine blue O (TBO were employed as selective virucidal treatment for destruction of exogenous bacteriophage. Laser and TBO can bring a total reduction in titer phage (ca. 10(8 pfu/mL without affecting the viability of L. monocytogenes cells. Artificially inoculated skimmed milk revealed mean populations of the bacteria as low as between 13 cfu/mL (1.11 log cfu/mL, after a 10-h assay duration. Virucidal laser treatment demonstrated better protection of Listeria cells than the other agents previously tested. The protocol was faster and easier to perform than standard procedures. This protocol constitutes an alternative for rapid, sensitive and quantitative detection of L. monocytogenes.

  8. Bacteriophage infections of microbiota can lead to leaky gut in an experimental rodent model.

    Science.gov (United States)

    Tetz, George; Tetz, Victor

    2016-01-01

    Increased intestinal permeability and translocation of gut microbiota from the intestinal lumen to the systemic circulation predispose patients to various diseases and may be one of the main triggers thereof. The role of microbiota in increased intestinal permeability is under intensive investigation. Here, we studied alterations in the host and increased intestinal permeability as a direct effect of treatment with a bacteriophage cocktail. After 10 days of challenge, the rats showed weight loss, messy hair, and decreased activity. Additionally, they displayed a significantly elevated lactulose:mannitol ratio and the level of circulating immune complexes. To our knowledge, this study demonstrates for the first time that increased intestinal permeability may be induced by bacteriophages that affect the microbiota. PMID:27340433

  9. Eradication of Salmonella Typhimurium in broiler chicks by combined use of P22 bacteriophage and probiotic

    Directory of Open Access Journals (Sweden)

    Guilherme Augusto Marietto Gonçalves

    2011-06-01

    Full Text Available It has been reported that the phage therapy is effective in controlling the number of colony-forming unit (CFU of Salmonella spp. in chicken gut. This paper describes the protective effect of phage and Lactobacilli administration on Salmonella infection in 1-day-old chicks. We administered the bacteriophage P22 in a single dose and a probiotic mixture of four species of bacteriocin-producing Lactobacillus once a day for one week. Samples were analyzed every 48 hours, and intestinal eradication of S. Typhimurium was confirmed after treatments. We observed an increase in the size of duodenal villi and cecal crypts, as well as an increase in body weight in groups that received daily doses of Lactobacilli. This study confirms the efficiency of bacteriophage therapy in controlling salmonellosis in chicks and the beneficial effect of Lactobacilli mixtures in the weight gain of the birds.

  10. Identifying and analyzing bacteriophages in human fecal samples: what could we discover?

    Science.gov (United States)

    Muniesa, Maite; Jofre, Juan

    2014-01-01

    The human gut is a complex ecosystem, densely populated with microbes including enormous amounts of phages. Metagenomic studies indicate a great diversity of bacteriophages, and because of the variety of gut bacterial species, the human or animal gut is probably a perfect ecological niche for phages that can infect and propagate in their bacterial communities. In addition, some phages have the capacity to mobilize genes, as demonstrated by the enormous fraction of phage particles in feces that contain bacterial DNA. All these facts indicate that, through predation and horizontal gene transfer, bacteriophages play a key role in shaping the size, structure and function of intestinal microbiomes, although our understanding of their effects on gut bacterial populations is only just beginning.

  11. Automatic detection and morphological delineation of bacteriophages in electron microscopy images.

    Science.gov (United States)

    Gelzinis, A; Verikas, A; Vaiciukynas, E; Bacauskiene, M; Sulcius, S; Simoliunas, E; Staniulis, J; Paskauskas, R

    2015-09-01

    Automatic detection, recognition and geometric characterization of bacteriophages in electron microscopy images was the main objective of this work. A novel technique, combining phase congruency-based image enhancement, Hough transform-, Radon transform- and open active contours with free boundary conditions-based object detection was developed to detect and recognize the bacteriophages associated with infection and lysis of cyanobacteria Aphanizomenon flos-aquae. A random forest classifier designed to recognize phage capsids provided higher than 99% accuracy, while measurable phage tails were detected and associated with a correct capsid with 81.35% accuracy. Automatically derived morphometric measurements of phage capsids and tails exhibited lower variability than the ones obtained manually. The technique allows performing precise and accurate quantitative (e.g. abundance estimation) and qualitative (e.g. diversity and capsid size) measurements for studying the interactions between host population and different phages that infect the same host.

  12. Efficient engineering of a bacteriophage genome using the type I-E CRISPR-Cas system.

    Science.gov (United States)

    Kiro, Ruth; Shitrit, Dror; Qimron, Udi

    2014-01-01

    The clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) system has recently been used to engineer genomes of various organisms, but surprisingly, not those of bacteriophages (phages). Here we present a method to genetically engineer the Escherichia coli phage T7 using the type I-E CRISPR-Cas system. T7 phage genome is edited by homologous recombination with a DNA sequence flanked by sequences homologous to the desired location. Non-edited genomes are targeted by the CRISPR-Cas system, thus enabling isolation of the desired recombinant phages. This method broadens CRISPR Cas-based editing to phages and uses a CRISPR-Cas type other than type II. The method may be adjusted to genetically engineer any bacteriophage genome.

  13. Structural basis of RNA binding discrimination between bacteriophages Qbeta and MS2.

    Science.gov (United States)

    Horn, Wilf T; Tars, Kaspars; Grahn, Elin; Helgstrand, Charlotte; Baron, Andrew J; Lago, Hugo; Adams, Chris J; Peabody, David S; Phillips, Simon E V; Stonehouse, Nicola J; Liljas, Lars; Stockley, Peter G

    2006-03-01

    Sequence-specific interactions between RNA stem-loops and coat protein (CP) subunits play vital roles in the life cycles of the RNA bacteriophages, e.g., by allowing translational repression of their replicase cistrons and tagging their own RNA genomes for encapsidation. The CPs of bacteriophages Qbeta and MS2 each discriminate in favor of their cognate translational operators, even in the presence of closely related operators from other phages in vivo. Discrete mutations within the MS2 CP have been shown to relax this discrimination in vitro. We have determined the structures of eight complexes between such mutants and both MS2 and Qbeta stem-loops with X-ray crystallography. In conjunction with previously determined in vivo repression data, the structures enable us to propose the molecular basis for the discrimination mechanism. PMID:16531233

  14. Inactivation of Escherichia coli O157:H7 attached to spinach harvester blade using bacteriophage.

    Science.gov (United States)

    Patel, Jitendra; Sharma, Manan; Millner, Patricia; Calaway, Todd; Singh, Manpreet

    2011-04-01

    Outbreaks associated with leafy greens have focused attention on the transfer of human pathogens to these commodities during harvest with commercial equipment. Attachment of Escherichia coli O157:H7 on new or rusty spinach harvester blades immersed in spinach extract or 10% tryptic soy broth (TSB) was investigated. Bacteriophages specific for E. coli O157:H7 were evaluated to kill cells attached to blade. A cocktail of five nalidixic acid-resistant E. coli O157:H7 isolates was transferred to 25 mL of spinach extract or 10% TSB. A piece of sterilized spinach harvester blade (2×1") was placed in above spinach extract or 10% TSB and incubated at room (22 °C) or dynamic (30 °C day, 20 °C night) temperatures. E. coli O157:H7 populations attached to blade during incubation in spinach extract or 10% TSB were determined. When inoculated at 1 log CFU/mL, E. coli O157:H7 attachment to blades after 24 and 48 h incubation at dynamic temperature (6.09 and 6.37 log CFU/mL) was significantly higher than when incubated at 22 °C (4.84 and 5.68 log CFU/mL), respectively. After 48 h incubation, two blades were sprayed on each side with a cocktail of E. coli O157-specific bacteriophages before scraping the blade, and subsequent plating on Sorbitol MacConkey media-nalidixic acid. Application of bacteriophages reduced E. coli O157:H7 populations by 4.5 log CFU on blades after 2 h of phage treatment. Our study demonstrates that E. coli O157:H7 can attach to and proliferate on spinach harvester blades under static and dynamic temperature conditions, and bacteriophages are able to reduce E. coli O157:H7 populations adhered to blades.

  15. DNA ejection from bacteriophage: towards a general behavior for osmotic suppression experiments

    CERN Document Server

    Castelnovo, Martin

    2007-01-01

    We present in this work in vitro measurements of the force ejecting DNA from two distinct bacteriophages (T5 and lambda) using the smotic-suppression technique. Our data are analyzed by revisiting the current theories of DNA packaging in spherical capsids. In particular we show that a simplified analytical model based on bending considerations only is able to account quantitatively for the experimental findings. Physical and biological consequences are discussed.

  16. Interpretation of damage to mammalian cells, E. coli and bacteriophages by incorporated radionuclides for prolonged irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Younis, A.-R.S.; Watt, D.E. (Saint Andrews Univ. (UK). Dept. of Physics)

    1990-01-01

    Previous analysis of published survival data for Auger electron and beta emitting nuclides incorporated into mammalian cells have been extended to include E. coli and bacteriophages. A unified scheme for the expression of damage is explored in terms of the localised secondary charged particle fluence of electrons, their average mean free path for ionisation and the number of DNA segments at risk in the target. (author).

  17. Physiological and Molecular Characterization of Salmonella Bacteriophages Previously Used in Phage Therapy.

    Science.gov (United States)

    Zhang, J; Hong, Y; Fealey, M; Singh, A; Walton, K; Martin, C; Harman, N J; Mahlie, J; Ebner, P D

    2015-12-01

    The use of bacteriophages as biocontrol agents to control Salmonella in food production has gained popularity over the last two decades. Previously, our laboratory demonstrated that bacteriophages can be direct fed to limit Salmonella colonization and transmission in pigs. Here, we characterized the bacteriophages in our treatment cocktail in terms of lytic spectrum, growth kinetics, survivability under various conditions, and genomic sequencing. PCR-based fingerprinting indicated that 9 of the 10 phages, while related, were distinct isolates. Single-step growth kinetics analysis determined that the eclipse periods, latent periods, and burst sizes averaged 21.5 min, 31.5 min, and 43.3 particles, respectively. The viability of the phages was measured after exposure to various pH ranges, temperatures, digestive enzymes, UV light, and chlorinated water. Temperatures greater than 87.5°C, pH of <2.0, UV light (302 and 365 nm), and chlorinated water (500 ppm) inactivated the tested phages. Only select bacteriophages, however, were affected by incubation at temperatures of ≤75.0°C or pH of 4.0 to 10.0. Genomic sequencing of the phage with the broadest spectrum in the collection (effectively lysed all four Salmonella serovars tested), vB_SalM_SJ2, revealed it to belong to the Viunalikevirus genus of the Myoviridae family. Of the 197 predicted open reading frames, no toxin-associated, lysogenic, Salmonella virulence, or antimicrobial resistance genes were identified. Taken together, these data indicate that phages, as biologicals, may require some manner of protection (e.g., microencapsulation) to remain viable under various physiological and manufacturing conditions. In addition, based on its ability to effectively lyse diverse Salmonella serovars, phage vB_SalM-SJ2 could be further developed as an important biocontrol agent in various aspects of food production when the exact serovar or strain of contaminating Salmonella is not yet known.

  18. Genome sequence of a new Streptomyces coelicolor generalized transducing bacteriophage, ΦCAM.

    Science.gov (United States)

    Monson, Rita; Salmond, George P C

    2012-12-01

    Streptomyces coelicolor is a model system for the study of Streptomyces, a genus of bacteria responsible for the production of many clinically important antibiotics. Here we report the genome sequence of ΦCAM, a new S. coelicolor generalized transducing bacteriophage, isolated from a soil sample originating from Lincolnshire, United Kingdom. Many open reading frames within ΦCAM shared high levels of similarity to a prophage from Salinispora tropica and a putative prophage in Streptomyces sp. strain C.

  19. Antibody producing capacity to the bacteriophage phi X174 in yersinia arthritis.

    OpenAIRE

    Bucknall, R.; Leirisalo-Repo, M; Laitinen, O; Jones, J V

    1987-01-01

    Antibody production in response to the primary immunogen bacteriophage phi X174 was investigated in 14 patients with previous yersinia arthritis (YA) and in 15 controls. HLA-B27 occurred in 10 patients with YA and in three controls. After primary and secondary immunisation the antibody responses were essentially similar both in patients with YA and controls. Consequently our results suggest that antibody response to a foreign antigen does not differ between patients with YA and a normal contr...

  20. Novel bacteriophage therapy for controlling metallo-beta-lactamase producing Pseudomonas aeruginosa infection in Catfish

    OpenAIRE

    Khairnar, Krishna; Raut, Mahendra P; Rajshree H. Chandekar; Sanmukh, Swapnil G; Waman N. PAUNIKAR

    2013-01-01

    Background The bacteriophage therapy is an effective antimicrobial approach with potentially important applications in medicine and biotechnology which can be seen as an additional string in the bow. Emerging drug resistant bacteria in aquaculture industry due to unrestricted use of antibiotics warrants more sustainable and environmental friendly strategies for controlling fish infections. The isolated bacteria from fish lesions was characterised based on isolation on selective and differenti...

  1. Isolation and Characterization of Bacteriophages Infecting Nocardioforms in Wastewater Treatment Plant

    OpenAIRE

    Khairnar, Krishna; Pal, Preeti; Rajshree H. Chandekar; Waman N. PAUNIKAR

    2014-01-01

    Activated sludge plants (ASP) are associated with the stable foaming problem worldwide. Apart from the physical and chemical treatment methods, biological treatment method has been least explored and may prove to be a novel and ecofriendly approach to tackle the problem of stable foam formation. In ASP Nocardia species are commonly found and are one of the major causes for forming sticky and stable foam. This study describes the isolation and characterization of three Nocardia bacteriophages ...

  2. Dark Matter of the Biosphere: the Amazing World of Bacteriophage Diversity.

    Science.gov (United States)

    Hatfull, Graham F

    2015-08-01

    Bacteriophages are the most abundant biological entities in the biosphere, and this dynamic and old population is, not surprisingly, highly diverse genetically. Relative to bacterial genomics, phage genomics has advanced slowly, and a higher-resolution picture of the phagosphere is only just emerging. This view reveals substantial diversity even among phages known to infect a common host strain, but the relationships are complex, with mosaic genomic architectures generated by illegitimate recombination over a long period of evolutionary history.

  3. Isolation and Preliminary Characterization of Twenty Bacteriophages Infecting Either Brevibacterium or Arthrobacter Strains

    OpenAIRE

    Trautwetter, Annie; Blanco, Carlos

    1988-01-01

    Thirty-seven bacteriophages plaquing on Corynebacterium, Brevibacterium, or Arthrobacter strains were isolated from soil or vegetation samples. Restriction analysis of phage DNA indicated that 20 phages were unique; one of them produced entirely turbid plaques on Brevibacterium ketoglutamicum and was characterized as temperate. All these phages were assigned to group B of the classification of Bradley (Bacteriol. Rev. 31:230-314, 1967) and had relatively narrow host ranges.

  4. Expression of the bacteriophage T4 denV structural gene in Escherichia coli

    International Nuclear Information System (INIS)

    The expression of the T4 denV gene, which previously had been cloned in plasmid constructs downstream of the bacteriophage lambda hybrid promoter-operator oLpR, was analyzed under a variety of growth parameters. Expression of the denV gene product, endonuclease V, was confirmed in DNA repair-deficient Escherichia coli (uvrA recA) by Western blot analyses and by enhancements of resistance to UV irradiation

  5. Elucidating the pH-Dependent Structural Transition of T7 Bacteriophage Endolysin.

    Science.gov (United States)

    Sharma, Meenakshi; Kumar, Dinesh; Poluri, Krishna Mohan

    2016-08-23

    Bacteriophages are the most abundant and diverse biological entities on earth. Bacteriophage endolysins are unique peptidoglycan hydrolases and have huge potential as effective enzybiotics in various infectious models. T7 bacteriophage endolysin (T7L), also known as N-acetylmuramoyl-l-alanine amidase or T7 lysozyme, is a 17 kDa protein that lyses a range of Gram-negative bacteria by hydrolyzing the amide bond between N-acetylmuramoyl residues and the l-alanine of the peptidoglycan layer. Although the activity profiles of several of the T7 family members have been known for many years, the molecular basis for their pH-dependent differential activity is not clear. In this study, we explored the pH-induced structural, stability, and activity characteristics of T7L by applying a variety of biophysical techniques and protein nuclear magnetic resonance (NMR) spectroscopy. Our studies established a reversible structural transition of T7L below pH 6 and the formation of a partially denatured conformation at pH 3. This low-pH conformation is thermally stable and exposed its hydrophobic pockets. Further, NMR relaxation measurements and structural analysis unraveled that T7L is highly dynamic in its native state and a network of His residues are responsible for the observed pH-dependent conformational dynamics and transitions. As bacteriophage chimeric and engineered endolysins are being developed as novel therapeutics against multiple drug resistance pathogens, we believe that our results are of great help in designing these entities as broadband antimicrobial and/or antibacterial agents. PMID:27513288

  6. Isolation of Acanthamoeba-Specific Antibodies from a Bacteriophage Display Library

    OpenAIRE

    Khan, Naveed A.; Greenman, John; Topping, Katherine P.; Victoria C. Hough; Temple, Graham S.; Paget, Timothy A.

    2000-01-01

    Acanthamoeba causes opportunistic eye infections in humans, which can lead to severe keratitis and may ultimately result in blindness. Current methods for identifying this organism rely on culture and microscopy. In this paper, we describe the isolation of antibody fragments that can be used for the unequivocal identification of Acanthamoeba. A bacteriophage antibody display library was used to isolate antibody fragments that bind specifically to Acanthamoeba. Individual clones were studied b...

  7. A genomic approach to understand interactions between Streptococcus pneumoniae and its bacteriophages

    OpenAIRE

    Leprohon, Philippe; Gingras, Hélène; Ouennane, Siham; Moineau, Sylvain; Ouellette, Marc

    2015-01-01

    Background Bacteriophage replication depends on bacterial proteins and inactivation of genes coding for such host factors should interfere with phage infection. To gain further insights into the interactions between S. pneumoniae and its pneumophages, we characterized S. pneumoniae mutants selected for resistance to the virulent phages SOCP or Dp-1. Results S. pneumoniae R6-SOCPR and R6-DP1R were highly resistant to the phage used for their selection and no cross-resistance between the two ph...

  8. Chemical factors influencing adsorption of bacteriophage MS2 to membrane filters.

    OpenAIRE

    Farrah, S R

    1982-01-01

    Antichaotropic salts, such as magnesium sulfate, and metal chelators, such as citrate ions, promoted adsorption of bacteriophage MS2 to membrane filters. In contrast, compounds that disrupt hydrophobic interactions, such as chaotropic salts, urea, Tween 80, and ethanol, did not promote adsorption of MS2 to membrane filters and counteracted the ability of magnesium sulfate to promote such adsorption. These results provide evidence that magnesium sulfate promotes the association of MS2 with mem...

  9. Translesion synthesis is the main component of SOS repair in bacteriophage lambda DNA.

    OpenAIRE

    Defais, M; Lesca, C; Monsarrat, B.; Hanawalt, P

    1989-01-01

    Agents that interfere with DNA replication in Escherichia coli induce physiological adaptations that increase the probability of survival after DNA damage and the frequency of mutants among the survivors (the SOS response). Such agents also increase the survival rate and mutation frequency of irradiated bacteriophage after infection of treated bacteria, a phenomenon known as Weigle reactivation. In UV-irradiated single-stranded DNA phage, Weigle reactivation is thought to occur via induced, e...

  10. Stepwise Expansion of the Bacteriophage φ6 Procapsid: Possible Packaging Intermediates

    OpenAIRE

    Nemecek, Daniel; Cheng, Naiqian; Qiao, Jian; Mindich, Leonard; Steven, Alasdair C; Heymann, J. Bernard

    2011-01-01

    The initial assembly product of bacteriophage φ6, the procapsid, undergoes major structural transformation during the sequential packaging of its three segments of single-stranded RNA. The procapsid, a compact icosahedrally symmetric particle with deeply recessed vertices, expands to the spherical mature capsid, increasing the volume available to accommodate the genome by 2.5-fold. It has been proposed that expansion and packaging are linked, with each stage in expansion presenting a binding ...

  11. Computer Simulations of DNA Packing inside Bacteriophages: Elasticity, Electrostatics and Entropy

    OpenAIRE

    Marenduzzo, D.

    2008-01-01

    There is now a considerable literature on computer simulations of DNA packaging inside bacteriophage capsids. While most studies have reached a semiquantitative or qualitative agreement with single molecule packaging and ejection studies, several quantitative answers are to date still lacking, needing either more accurate measurements or more realistic or difficult simulations. Here, I briefly review the outstanding questions in this field and report some new numerical results on DNA packagin...

  12. Genome and Proteome of Campylobacter jejuni Bacteriophage NCTC 12673▿†

    OpenAIRE

    Kropinski, Andrew M.; Arutyunov, Denis; Foss, Mary; Cunningham, Anna; Ding, Wen; Singh, Amit; Pavlov, Andrey R.; Henry, Matthew; Evoy, Stephane; Kelly, John; Szymanski, Christine M.

    2011-01-01

    Campylobacter jejuni continues to be the leading cause of bacterial food-borne illness worldwide, so improvements to current methods used for bacterial detection and disease prevention are needed. We describe here the genome and proteome of C. jejuni bacteriophage NCTC 12673 and the exploitation of its receptor-binding protein for specific bacterial detection. Remarkably, the 135-kb Myoviridae genome of NCTC 12673 differs greatly from any other proteobacterial phage genome described (includin...

  13. Plasmid biology of natural Lactococcus lactis strains and molecular mechanisms of bacteriophage-host interaction

    OpenAIRE

    Fallico, Vincenzo

    2011-01-01

    Lacticin 3147, enterocin AS-48, lacticin 481, variacin, and sakacin P are bacteriocins offering promising perspectives in terms of preservation and shelf-life extension of food products and should find commercial application in the near future. The studies detailing their characterization and bio-preservative applications are reviewed. Transcriptomic analyses showed a cell wall-targeted response of Lactococcus lactis IL1403 during the early stages of infection with the lytic bacteriophage c2,...

  14. Inhibition of Biofilm Formation by T7 Bacteriophages Producing Quorum-Quenching Enzymes

    OpenAIRE

    Pei, Ruoting; Lamas-Samanamud, Gisella R.

    2014-01-01

    Bacterial growth in biofilms is the major cause of recalcitrant biofouling in industrial processes and of persistent infections in clinical settings. The use of bacteriophage treatment to lyse bacteria in biofilms has attracted growing interest. In particular, many natural or engineered phages produce depolymerases to degrade polysaccharides in the biofilm matrix and allow access to host bacteria. However, the phage-produced depolymerases are highly specific for only the host-derived polysacc...

  15. Ecology of Anti-Biofilm Agents II: Bacteriophage Exploitation and Biocontrol of Biofilm Bacteria

    OpenAIRE

    Abedon, Stephen T.

    2015-01-01

    Bacteriophages are the viruses of bacteria. In the guise of phage therapy they have been used for decades to successfully treat what are probable biofilm-containing chronic bacterial infections. More recently, phage treatment or biocontrol of biofilm bacteria has been brought back to the laboratory for more rigorous assessment as well as towards the use of phages to combat environmental biofilms, ones other than those directly associated with bacterial infections. Considered in a companion ar...

  16. Participation of the lytic replicon in bacteriophage P1 plasmid maintenance.

    OpenAIRE

    Yarmolinsky, M B; Hansen, E B; Jafri, S; Chattoraj, D K

    1989-01-01

    P1 bacteriophage carries at least two replicons: a plasmid replicon and a viral lytic replicon. Since the isolated plasmid replicon can maintain itself stably at the low copy number characteristic of intact P1 prophage, it has been assumed that this replicon is responsible for driving prophage replication. We provide evidence that when replication from the plasmid replicon is prevented, prophage replication continues, albeit at a reduced rate. The residual plasmid replication is due to incomp...

  17. Inactivation of Listeria monocytogenes by disinfectants and bacteriophages in suspension and stainless steel carrier tests.

    Science.gov (United States)

    Chaitiemwong, N; Hazeleger, W C; Beumer, R R

    2014-12-01

    To simulate food contact surfaces with pits or cracks, stainless steel plates with grooves (depths between 0.2 and 5 mm) were constructed. These plates were artificially contaminated with Listeria monocytogenes in clean conditions, with organic soiling, or after 14 days of biofilm formation after which inactivation of the pathogen by Suma Tab D4 (sodium dichloroisocyanurate, 240 and 300 mg/liter), Suma Bac D10 (quaternary ammonium compound, 740 mg/liter), and bacteriophage suspension (Listex P100) was determined. Both chemical disinfectants performed well in suspension tests and in clean carrier tests according to the European standard with a reduction of more than 5 and 4 log units, respectively, of Listeria cells after 5 min of contact time. However, for the plates with grooves, the reduction could not meet the standard requirement, although a higher reduction of L. monocytogenes was observed in the shallow grooves compared with the deeper grooves. Furthermore, presence of food residues and biofilm reduced the effect of the disinfectants especially in the deep grooves, which was dependent on type of food substrate. Bacteriophages showed the best antimicrobial effect compared with the chemical disinfectants (sodium dichloroisocyanurate and quaternary ammonium compound) in most cases in the shallow grooves, but not in the deep grooves. The chlorine based disinfectants were usually less effective than quaternary ammonium compound. The results clearly demonstrate that surfaces with grooves influenced the antimicrobial effect of the chemical disinfectants and bacteriophages because the pathogen is protected in the deep grooves. The use of bacteriophages to inactivate pathogens on surfaces could be helpful in limited cases; however, use of large quantities in practice may be costly and phage-resistant strains may develop.

  18. pH-Induced Stability Switching of the Bacteriophage HK97 Maturation Pathway

    OpenAIRE

    May, Eric R.; Arora, Karunesh; Brooks, Charles L.

    2014-01-01

    Many viruses undergo large-scale conformational changes during their life cycles. Blocking the transition from one stage of the life cycle to the next is an attractive strategy for the development of antiviral compounds. In this work, we have constructed an icosahedrally symmetric, low-energy pathway for the maturation transition of bacteriophage HK97. By conducting constant-pH molecular dynamics simulations on this pathway, we identify which residues are contributing most significantly to sh...

  19. Experimental test of connector rotation during DNA packaging into bacteriophage phi29 capsids

    OpenAIRE

    Thorsten Hugel; Jens Michaelis; Hetherington, Craig L.; Jardine, Paul J.; Shelley Grimes; Walter, Jessica M.; Wayne Falk; Anderson, Dwight L.; Carlos Bustamante

    2007-01-01

    Author Summary The life cycles of many viruses include a self-assembly stage in which a powerful molecular motor packs the DNA genome into the virus's preformed shell (the capsid). Biochemical and biophysical studies have identified essential components of the packaging machinery and measured various characteristics of the packaging process, while crystallography and electron microscopy have provided snapshots of viral structure before and after packaging. In bacteriophage ϕ29 assembly, the D...

  20. The mom gene of bacteriophage Mu: the mechanism of methylation-dependent expression.

    OpenAIRE

    Seiler, A.; Blöcker, H; Frank, R.; Kahmann, R

    1986-01-01

    Transcription of the DNA modification gene (mom) of bacteriophage Mu requires methylation of three GATC sites upstream of the mom promoter by the Escherichia coli deoxyadenosine methylation function (Dam). The three sites map within a 40-bp segment termed region I. Small deletions, inversions, duplications and specific point mutations have been introduced in region I. Their effect on mom expression has been studied in dam+ and dam strains. Dam-dependent expression of the mom gene requires a s...