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Sample records for bacteriophage hk97 studied

  1. 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...

  2. The Crystal Structure of Bacteriophage HK97 gp6: Defining a Large Family of Head-Tail Connector Proteins

    Energy Technology Data Exchange (ETDEWEB)

    Cardarelli, Lia; Lam, Robert; Tuite, Ashleigh; Baker, Lindsay A; Sadowski, Paul D; Radford, Devon R; Rubinstein, John L; Battaile, Kevin P; Chirgadze, Nickolay; Maxwell, Karen L; Davidson, Alan R [UHN; (Toronto); (HWMRI)

    2011-11-23

    The final step in the morphogenesis of long-tailed double-stranded DNA bacteriophages is the joining of the DNA-filled head to the tail. The connector is a specialized structure of the head that serves as the interface for tail attachment and the point of egress for DNA from the head during infection. Here, we report the determination of a 2.1 Å crystal structure of gp6 of bacteriophage HK97. Through structural comparisons, functional studies, and bioinformatic analysis, gp6 has been determined to be a component of the connector of phage HK97 that is evolutionarily related to gp15, a well-characterized connector component of bacteriophage SPP1. Whereas the structure of gp15 was solved in a monomeric form, gp6 crystallized as an oligomeric ring with the dimensions expected for a connector protein. Although this ring is composed of 13 subunits, which does not match the symmetry of the connector within the phage, sequence conservation and modeling of this structure into the cryo-electron microscopy density of the SPP1 connector indicate that this oligomeric structure represents the arrangement of gp6 subunits within the mature phage particle. Through sequence searches and genomic position analysis, we determined that gp6 is a member of a large family of connector proteins that are present in long-tailed phages. We have also identified gp7 of HK97 as a homologue of gp16 of phage SPP1, which is the second component of the connector of this phage. These proteins are members of another large protein family involved in connector assembly.

  3. pH-induced stability switching of the bacteriophage HK97 maturation pathway.

    Science.gov (United States)

    May, Eric R; Arora, Karunesh; Brooks, Charles L

    2014-02-26

    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 shifting the stability between the states along the pathway under differing pH conditions. We further analyze these data to establish the connection between critical residues and important structural motifs which undergo reorganization during maturation. We go on to show how DNA packaging can induce spontaneous reorganization of the capsid during maturation. PMID:24495192

  4. Theory of morphological transformation of viral capsid shell during the maturation process in the HK97 bacteriophage and similar viruses

    Science.gov (United States)

    Konevtsova, O. V.; Lorman, V. L.; Rochal, S. B.

    2016-05-01

    We consider the symmetry and physical origin of collective displacement modes playing a crucial role in the morphological transformation during the maturation of the HK97 bacteriophage and similar viruses. It is shown that the experimentally observed hexamer deformation and pentamer twist in the HK97 procapsid correspond to the simplest irreducible shear strain mode of a spherical shell. We also show that the icosahedral faceting of the bacteriophage capsid shell is driven by the simplest irreducible radial displacement field. The shear field has the rotational icosahedral symmetry group I while the radial field has the full icosahedral symmetry Ih. This difference makes their actions independent. The radial field sign discriminates between the icosahedral and the dodecahedral shapes of the faceted capsid shell, thus making the approach relevant not only for the HK97-like viruses but also for the parvovirus family. In the frame of the Landau-Ginzburg formalism we propose a simple phenomenological model valid for the first reversible step of the HK97 maturation process. The calculated phase diagram illustrates the discontinuous character of the virus shape transformation. The characteristics of the virus shell faceting and expansion obtained in the in vitro and in vivo experiments are related to the decrease in the capsid shell thickness and to the increase of the internal capsid pressure.

  5. Theory of morphological transformation of viral capsid shell during the maturation process in the HK97 bacteriophage and similar viruses.

    Science.gov (United States)

    Konevtsova, O V; Lorman, V L; Rochal, S B

    2016-05-01

    We consider the symmetry and physical origin of collective displacement modes playing a crucial role in the morphological transformation during the maturation of the HK97 bacteriophage and similar viruses. It is shown that the experimentally observed hexamer deformation and pentamer twist in the HK97 procapsid correspond to the simplest irreducible shear strain mode of a spherical shell. We also show that the icosahedral faceting of the bacteriophage capsid shell is driven by the simplest irreducible radial displacement field. The shear field has the rotational icosahedral symmetry group I while the radial field has the full icosahedral symmetry I_{h}. This difference makes their actions independent. The radial field sign discriminates between the icosahedral and the dodecahedral shapes of the faceted capsid shell, thus making the approach relevant not only for the HK97-like viruses but also for the parvovirus family. In the frame of the Landau-Ginzburg formalism we propose a simple phenomenological model valid for the first reversible step of the HK97 maturation process. The calculated phase diagram illustrates the discontinuous character of the virus shape transformation. The characteristics of the virus shell faceting and expansion obtained in the in vitro and in vivo experiments are related to the decrease in the capsid shell thickness and to the increase of the internal capsid pressure.

  6. The tripartite capsid gene of Salmonella phage Gifsy-2 yields a capsid assembly pathway engaging features from HK97 and λ

    International Nuclear Information System (INIS)

    Phage Gifsy-2, a lambdoid phage infecting Salmonella, has an unusually large composite gene coding for its major capsid protein (mcp) at the C-terminal end, a ClpP-like protease at the N-terminus, and a ∼ 200 residue central domain of unknown function but which may have a scaffolding role. This combination of functions on a single coding region is more extensive than those observed in other phages such as HK97 (scaffold-capsid fusion) and λ (protease-scaffold fusion). To study the structural phenotype of the unique Gifsy-2 capsid gene, we have purified Gifsy-2 particles and visualized capsids and procapsids by cryoelectron microscopy, determining structures to resolutions up to 12 A. The capsids have lambdoid T = 7 geometry and are well modeled with the atomic structures of HK97 mcp and phage λ gpD decoration protein. Thus, the unique Gifsy-2 capsid protein gene yields a capsid maturation pathway engaging features from both phages HK97 and λ.

  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. 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

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. [Studies on the repair of damaged DNA in bacteriophage, bacterial and mammalian systems]: Final report

    International Nuclear Information System (INIS)

    This study sought to exploit the use of uv radiation as a source of genomic damage. We explored the molecular mechanism of the repair of DNA damage at a number of different levels of biological organization, by investigating bacteriophage, bacterial, yeast and mammalian cells. Not only have observations obtained in one biological system suggested specific experimental approaches in others, but we have also learned that some biochemical pathways for DNA repair are unique to specific organisms. Our studies are summarized in terms of 4 major areas of research activity that span the past 16 years. 86 refs

  19. Extraction and Study of Bacteriophages, Used against Agents of Potato Soft Rot

    Directory of Open Access Journals (Sweden)

    Magda D. Davitashvili

    2012-12-01

    Full Text Available The use of specific bacteriophages and their complex mixtures against bacterial diseases is very effective. As for causative agent of potato soft rot Erwinia carotovora, specific phages (25 phages in total were extracted from diseased potato, soil and sewage. The study of their biological properties showed the diversity of phages in terms of lytic action, virion plaque and morphology, as well as in relation to different environmental factors. Phages showed explicit antibacterial activity in vitro in liquid and solid media, as well as during model tests of potato tubers artificial inoculation.

  20. Second collaborative study on analysis of bacteriophages in bathing waters

    NARCIS (Netherlands)

    Mooijman KA; Ghameshlou Z; Bahar M; Havelaar AH; MGB

    1999-01-01

    Het tweede internationale ringonderzoek met bacteriofagen in zwemwater werd in maart 1998 georganiseerd. Vijftien Europese laboratoria (inclusief het organiserende laboratorium) namen deel aan de studie. De studie bestond uit twee delen: (1) Analyse van natuurlijk besmette standaard monsters for d

  1. First collaborative study on bacteriophages in bathing waters

    NARCIS (Netherlands)

    Mooijman KA; Ghameshlou Z; Bahar M; Havelaar AH; MGB

    1998-01-01

    Het eerste internationale ringonderzoek met bacteriofagen in zwemwater werd in mei 1997 georganiseerd. Zestien Europese laboratoria (inclusief het organiserende laboratorium) namen deel aan de studie. Zij analyseerden faag referentiematerialen (RMs) voor de bepaling van somatische colifagen (RMs m

  2. A Single Molecule Study of Two Bacteriophage Epigenetic Switches

    Science.gov (United States)

    Wang, Haowei

    Epigenetic switches allow organisms to evolve into different states by activating/repressing different sets of genes without mutations of the underlying DNA sequence. The study of epigenetic switches is very important to understand the mechanism of human development, the origin of cancer, mental illness and fundamental processes such as gene regulation. The coliphage lambda epigenetic switch, which allows switching from lysogeny to lysis, has been studied for more than 50 years as a paradigm, and has recently received renewed attention. Atomic force microscopy (AFM) was used here to show that the lambda repressor oligomerizes on DNA, primarily as a dodecamer, to secure a DNA loop, which is the basis of the lambda switch. This study also provides support for the idea that specifically bound repressor stabilizes adjacent, non-specifically bound repressor molecules, which confers robustness to the switch. 186 is a member of a different coliphage family. One of the major differences between the two coliphage families is that lambda phages can be induced to switch from the lysogenic to the lytic state by UV radiation, but most coliphages of P2 family, to which 186 belongs, cannot. Interaction between coliphage 186 repressor and DNA is characterized by AFM and tethered particle motion (TPM). To expedite analysis of the AFM data, MatLab codes were written to automate the laborious, manual tracing procedures. The programs automatically recognize DNA segments and protein particles in an image, in order to measure the DNA length and position of bound particles as well as their height, diameter and volume. Application of these algorithms greatly improved the efficiency of AFM analysis. It was showed that 186 CI dimers form heptameric wheels, which induce DNA wrapping and different kinds of DNA looping producing various conformations of nucleoprotein complexes. Information about the dynamics of DNA wrapping and looping on 186 CI particles was also obtained by TPM.

  3. 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.

  4. Microbiological study of bacteriophage induction in the presence of chemical stress factors in enhanced biological phosphorus removal (EBPR).

    Science.gov (United States)

    Motlagh, Amir Mohaghegh; Bhattacharjee, Ananda S; Goel, Ramesh

    2015-09-15

    Polyphosphate accumulating organisms (PAOs) are responsible for carrying the enhanced biological phosphorus removal (EBPR). Although the EBPR process is well studied, the failure of EBPR performance at both laboratory and full-scale plants has revealed a lack of knowledge about the ecological and microbiological aspects of EBPR processes. Bacteriophages are viruses that infect bacteria as their sole host. Bacteriophage infection of polyphosphate accumulating organisms (PAOs) has not been considered as a main contributor to biological phosphorus removal upsets. This study examined the effects of different stress factors on the dynamics of bacteriophages and the corresponding effects on the phosphorus removal performance in a lab-scale EBPR system. The results showed that copper (heavy metal), cyanide (toxic chemical), and ciprofloxacin (antibiotic), as three different anthropogenic stress factors, can induce phages integrated onto bacterial genomes (i.e. prophages) in an enriched EBPR sequencing batch reactor, resulting in a decrease in the polyphosphate kinase gene ppk1 clades copy number, phosphorus accumulation capacity, and phosphorus removal performance. This study opens opportunities for further research on the effects of bacteriophages in nutrient cycles both in controlled systems such as wastewater treatment plants and natural ecosystems. PMID:26024959

  5. 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.

  6. Spectroscopic Studies on the Binding of Bacteriophage Mequindox with Bovine Serum Albumin

    Institute of Scientific and Technical Information of China (English)

    ZENG,Zhouhua; LIU,Yi; HU,Xianming; XU,Zhenqiang; ZENG,Kun

    2009-01-01

    Fluorescence spectra and UV-Vis absorption spectra have been used to study the binding of bacteriophage mequindox (MEQ) with bovine serum albumin (BSA),which performed a dynamic quenching process.The quenching constants and thermodynamic parameters at different temperatures were calculated.The binding was primarily driven by entropy,and hydrophobic forces also played a significant role.The distance between BSA and MEQ was estimated to be 4.5 nm based on the theory of F(o)rster's non-radioactive energy transfer.Furthermore,synchronous fluorescence spectra and 3-dimensional fluorescence spectra were used to figure out the configuration of BSA in the presence or absence of MEQ,which indicated that it was basically the same.

  7. Detection specificity studies of bacteriophage adhesin-coated long-period grating-based biosensor

    Science.gov (United States)

    Koba, Marcin; Śmietana, Mateusz; Brzozowska, Ewa; Górska, Sabina; Mikulic, Predrag; Cusano, Andrea; Bock, Wojtek J.

    2015-09-01

    In this work, we present a label-free detection specificity study of an optical fiber long-period grating (LPG) biosensor working near the dispersion turning point of higher order cladding modes. The LPG sensor functionalized with bacteriophage adhesin is tested with specific and non-specific bacteria dry weight. We show that such biosensor is able to selectively bind, thus recognize different bacteria. We use bacteria dry weights of E. coli B as positive test and E. coli K12 and Salmonella enterica as negative tests. The resonance wavelength shift induced by E. coli B reaches over 90 nm, while for E. coli K12 and Salmonella enterica approximately 40 and 20 nm, respectively.

  8. Initiation of bacteriophage Φ29 DNA packaging studied by optical tweezers manipulation of single DNA molecules

    Science.gov (United States)

    Rickgauer, John Peter; Fuller, Derek N.; Hu, Bo; Grimes, Shelley; Jardine, Paul J.; Anderson, Dwight L.; Smith, Douglas E.

    2006-08-01

    A key step in the life cycle of many viruses, including bacteriophages, adenoviruses, and herpesviruses, is the packaging of replicated viral genomes into pre-assembled proheads by the action of ATP-dependent portal motor complexes. Here we present a method that allows the initiation of packaging by single complexes to be studied using optical tweezers. A procedure is developed for assembling phage Φ29 prohead-motor complexes, which are demonstrated to bind and begin translocation of a target DNA molecule within only a few seconds. We show that the Φ29 DNA terminal protein (gene product 3), which functions to prime DNA replication, also has a dramatic effect on packaging. The DNA tether length measured immediately after binding varied from ~30-100% of the full length, yet shortened monotonically, indicating that packaging does not strictly begin at the terminal end of the DNA. Removal of the terminal protein eliminated this variability, causing packaging to initiate at or very near the end of the DNA. These findings, taken together with electron microscopy data, suggest that rather than simply threading into the portal, the motor captures and dynamically tensions a DNA loop, and that the function of the terminal protein is to load DNA segments on both sides of the loop junction onto separate DNA translocating units.

  9. 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

  10. 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

  11. 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.

  12. [A STUDY OF THE ISOLATED BACTERIOPHAGE ΦAB-SP7 ADSORPTION ON THE CELL SURFACE OF THE AZOSPIRILLUM BRASILENSE SP7].

    Science.gov (United States)

    Guliy, O I; Karavaeva, O A; Velikov, V A; Sokolov, O I; Pavily, S A; Larionova, O S; Burov, A M; Ignatov, O V

    2016-01-01

    The bacteriophage ΦAb-Sp7 was isolated from the cells of the Azospirillum brasilense Sp7. The morphology, size of the gram-negative colonies, and range of lytic activity against other strains and species of the genus Azospirillum was tested. The isolated phage DNA was examined using electrophoretic and restriction analysis, and the size of the genome were established. The electron microscopy. resuIts show that the phage (capsid) has a strand-like form. The electron microscopy study of the bacteriophage ΦAb-Sp7 adsorption on the A. brasilense Sp7 bacterial surface was performed.

  13. 一株溶藻弧菌噬菌体的生理特性研究%A Study of the Biochemical Characteristics of the Vibrio alginolyticus Bacteriophage

    Institute of Scientific and Technical Information of China (English)

    曾林; 邱德全; 谢警鸿; 于鸽

    2012-01-01

    The physiological characteristics of a Vibrio alginolyticus Bacteriophage was studied and the Bacteriophage was isolated from market of aquatic products in Zhanjiang. The results showed that the diameter of Bacteriophage plaque was l-1.5mm (12h). Lytic activity of Bacteriophage lost within 30 min when Bacteriophage exposed to UV light (20W, 30cm). Bacteriophage were UV-sensitive. They had strong lytic activity at pH 8 -11, and the optimum pH value was 11. The lytic cycle of them was 65 min. They were sensitive as the ambient temperature was more than 65℃. They were tolerated with ether and chloroform. They were sensitive to antiviral drugs acyclovir. Routine test dilution(RTD) was 106. Optimal multiplicity of infection was 10.%对从湛江市水产品批发市场分离得到一株溶藻弧菌噬菌体的生理特性进行测定,结果表明:该株噬菌体噬菌斑12h直径为1~1.5mm,对紫外线敏感,暴露在紫外灯(20W,30 cm)下30 min可丧失全部裂解活性;在pH8-11范围内裂解活性较强,最适pH值为11,裂解周期为65 min,对65℃以上的高温敏感,对乙醚和氯仿有较好的耐受性,对抗病毒药物阿昔洛韦敏感,最大常规稀释度为106 CFU/mL,最佳感染复数为10.

  14. Paradox of enrichment and system order reduction: bacteriophages dynamics as case study.

    Science.gov (United States)

    Korobeinikov, Andrei; Shchepakina, Elena; Sobolev, Vladimir

    2016-09-01

    The paradox of enrichment in a 3D model for bacteriophage dynamics, with a free infection stage of the phage and a bilinear incident rate, is considered. An application of the technique of singular perturbation theory allows us to demonstrate why the paradox arises in this 3D model despite the fact that it has a bilinear incident rate (while in 2D predator-prey models it is usually associated with the concavity of the attack rate). Our analysis demonstrates that the commonly applied approach of the model order reduction using the so-called quasi-steady-state approximation can lead to a loss of important properties of an original system.

  15. Bacteriophage Tailspikes and Bacterial O-Antigens as a Model System to Study Weak-Affinity Protein-Polysaccharide Interactions.

    Science.gov (United States)

    Kang, Yu; Gohlke, Ulrich; Engström, Olof; Hamark, Christoffer; Scheidt, Tom; Kunstmann, Sonja; Heinemann, Udo; Widmalm, Göran; Santer, Mark; Barbirz, Stefanie

    2016-07-27

    Understanding interactions of bacterial surface polysaccharides with receptor protein scaffolds is important for the development of antibiotic therapies. The corresponding protein recognition domains frequently form low-affinity complexes with polysaccharides that are difficult to address with experimental techniques due to the conformational flexibility of the polysaccharide. In this work, we studied the tailspike protein (TSP) of the bacteriophage Sf6. Sf6TSP binds and hydrolyzes the high-rhamnose, serotype Y O-antigen polysaccharide of the Gram-negative bacterium Shigella flexneri (S. flexneri) as a first step of bacteriophage infection. Spectroscopic analyses and enzymatic cleavage assays confirmed that Sf6TSP binds long stretches of this polysaccharide. Crystal structure analysis and saturation transfer difference (STD) NMR spectroscopy using an enhanced method to interpret the data permitted the detailed description of affinity contributions and flexibility in an Sf6TSP-octasaccharide complex. Dodecasaccharide fragments corresponding to three repeating units of the O-antigen in complex with Sf6TSP were studied computationally by molecular dynamics simulations. They showed that distortion away from the low-energy solution conformation found in the octasaccharide complex is necessary for ligand binding. This is in agreement with a weak-affinity functional polysaccharide-protein contact that facilitates correct placement and thus hydrolysis of the polysaccharide close to the catalytic residues. Our simulations stress that the flexibility of glycan epitopes together with a small number of specific protein contacts provide the driving force for Sf6TSP-polysaccharide complex formation in an overall weak-affinity interaction system. PMID:27045683

  16. 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.

  17. 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.

  18. 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.

  19. Studies of inactivation, retardation and accumulation of viruses in porous media by a combination of dye labeled and native bacteriophage probes

    Science.gov (United States)

    Gitis, Vitaly; Dlugy, Christina; Gun, Jenny; Lev, Ovadia

    2011-06-01

    Penetration of viruses through soils is governed by the processes of transport, reversible adsorption, accumulation and inactivation. Until now, it was difficult to decouple the latter two processes and accurately predict viral fate. The present work describes a novel method—tracer studies with a mixture of native and fluorescent-dyed bacteriophages—that facilitates parallel quantification of the two processes. When the native phages are experiencing both accumulation and inactivation, the labeled ones are inactivated already and therefore can only be accumulated. Thus the effect of inactivation is applicable to native bacteriophages only and depletion of phage concentration due to inactivation can be elucidated from a total phage balance. The novel approach is exemplified by batch and column studies of the effects of temperature, pH, and saturation, on inactivation of MS2 bacteriophage. A three-parameter model accounting for inactivation, reversible adsorption (i.e., retardation), and accumulation is implemented.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Structural and dynamics studies of a truncated variant of CI repressor from bacteriophage TP901-1

    DEFF Research Database (Denmark)

    Rasmussen, Kim Krighaar; Frandsen, Kristian E. H.; Erba, Elisabetta Boeri;

    2016-01-01

    The CI repressor from the temperate bacteriophage TP901-1 consists of two folded domains, an N-terminal helix-turn-helix DNA-binding domain (NTD) and a C-terminal oligomerization domain (CTD), which we here suggest to be further divided into CTD1 and CTD2. Full-length CI is a hexameric protein...

  5. Crystal and cryoEM structural studies of a cell wall degrading enzyme in the bacteriophage [psi]29 tail

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Ye; Morais, Marc C.; Cohen, Daniel N.; Bowman, Valorie D.; Anderson, Dwight L.; Rossmann, Michael G. (Purdue); (UMM)

    2009-08-28

    The small bacteriophage {phi}29 must penetrate the {approx}250-{angstrom} thick external peptidoglycan cell wall and cell membrane of the Gram-positive Bacillus subtilis, before ejecting its dsDNA genome through its tail into the bacterial cytoplasm. The tail of bacteriophage {phi}29 is noncontractile and {approx}380 {angstrom} long. A 1.8-{angstrom} resolution crystal structure of gene product 13 (gp13) shows that this tail protein has spatially well separated N- and C-terminal domains, whose structures resemble lysozyme-like enzymes and metallo-endopeptidases, respectively. CryoEM reconstructions of the WT bacteriophage and mutant bacteriophages missing some or most of gp13 shows that this enzyme is located at the distal end of the {phi}29 tail knob. This finding suggests that gp13 functions as a tail-associated, peptidoglycan-degrading enzyme able to cleave both the polysaccharide backbone and peptide cross-links of the peptidoglycan cell wall. Comparisons of the gp13{sup -} mutants with the {phi}29 mature and emptied phage structures suggest the sequence of events that occur during the penetration of the tail through the peptidoglycan layer.

  6. Three-dimensional reconstructions of the bacteriophage CUS-3 virion reveal a conserved coat protein I-domain but a distinct tailspike receptor-binding domain

    International Nuclear Information System (INIS)

    CUS-3 is a short-tailed, dsDNA bacteriophage that infects serotype K1 Escherichia coli. We report icosahedrally averaged and asymmetric, three-dimensional, cryo-electron microscopic reconstructions of the CUS-3 virion. Its coat protein structure adopts the “HK97-fold” shared by other tailed phages and is quite similar to that in phages P22 and Sf6 despite only weak amino acid sequence similarity. In addition, these coat proteins share a unique extra external domain (“I-domain”), suggesting that the group of P22-like phages has evolved over a very long time period without acquiring a new coat protein gene from another phage group. On the other hand, the morphology of the CUS-3 tailspike differs significantly from that of P22 or Sf6, but is similar to the tailspike of phage K1F, a member of the extremely distantly related T7 group of phages. We conclude that CUS-3 obtained its tailspike gene from a distantly related phage quite recently. - Highlights: • Asymmetric and symmetric three-dimensional reconstructions of phage CUS-3 are presented. • CUS-3 major capsid protein has a conserved I-domain, which is found in all three categories of “P22-like phage”. • CUS-3 has very different tailspike receptor binding domain from those of P22 and Sf6. • The CUS-3 tailspike likely was acquired by horizontal gene transfer

  7. Three-dimensional reconstructions of the bacteriophage CUS-3 virion reveal a conserved coat protein I-domain but a distinct tailspike receptor-binding domain

    Energy Technology Data Exchange (ETDEWEB)

    Parent, Kristin N., E-mail: kparent@msu.edu [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0378 (United States); Tang, Jinghua; Cardone, Giovanni [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0378 (United States); Gilcrease, Eddie B. [University of Utah School of Medicine, Division of Microbiology and Immunology, Department of Pathology, Salt Lake City, UT 84112 (United States); Janssen, Mandy E.; Olson, Norman H. [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0378 (United States); Casjens, Sherwood R., E-mail: sherwood.casjens@path.utah.edu [University of Utah School of Medicine, Division of Microbiology and Immunology, Department of Pathology, Salt Lake City, UT 84112 (United States); Baker, Timothy S., E-mail: tsb@ucsd.edu [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0378 (United States); University of California, San Diego, Division of Biological Sciences, La Jolla, CA, 92093 (United States)

    2014-09-15

    CUS-3 is a short-tailed, dsDNA bacteriophage that infects serotype K1 Escherichia coli. We report icosahedrally averaged and asymmetric, three-dimensional, cryo-electron microscopic reconstructions of the CUS-3 virion. Its coat protein structure adopts the “HK97-fold” shared by other tailed phages and is quite similar to that in phages P22 and Sf6 despite only weak amino acid sequence similarity. In addition, these coat proteins share a unique extra external domain (“I-domain”), suggesting that the group of P22-like phages has evolved over a very long time period without acquiring a new coat protein gene from another phage group. On the other hand, the morphology of the CUS-3 tailspike differs significantly from that of P22 or Sf6, but is similar to the tailspike of phage K1F, a member of the extremely distantly related T7 group of phages. We conclude that CUS-3 obtained its tailspike gene from a distantly related phage quite recently. - Highlights: • Asymmetric and symmetric three-dimensional reconstructions of phage CUS-3 are presented. • CUS-3 major capsid protein has a conserved I-domain, which is found in all three categories of “P22-like phage”. • CUS-3 has very different tailspike receptor binding domain from those of P22 and Sf6. • The CUS-3 tailspike likely was acquired by horizontal gene transfer.

  8. 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.

  9. 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.

  10. [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).

  11. 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

  12. 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.

  13. 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.

  14. Studies of viral DNA packaging motors with optical tweezers: a comparison of motor function in bacteriophages φ29, λ, and T4

    Science.gov (United States)

    Smith, Douglas E.; Fuller, Derek N.; Raymer, Dorian M.; Rickgauer, Peter; Grimes, Shelley; Jardine, Paul J.; Anderson, Dwight L.; Catalano, Carlos E.; Kottadiel, Vishal; Rao, Venigalla B.

    2007-09-01

    A key step in the assembly of many viruses is the packaging of double-stranded DNA into a viral procapsid (an empty protein shell) by the action of an ATP-powered portal motor complex. We have developed methods to measure the packaging of single DNA molecules into single viral proheads in real time using optical tweezers. We can measure DNA binding and initiation of translocation, the DNA translocation dynamics, and the filling of the capsid against resisting forces. In addition to studying bacteriophage φ29, we have recently extended these methods to study the E. coli bacteriophages λ and T4, two important model systems in molecular biology. The three systems have different capsid sizes/shapes, genome lengths, and biochemical and structural differences in their packaging motors. Here, we compare and contrast these three systems. We find that all three motors translocate DNA processively and generate very large forces, each exceeding 50 piconewtons, ~20x higher force than generated by the skeletal muscle myosin 2 motor. This high force generation is required to overcome the forces resisting the confinement of the stiff, highly charged DNA at high density within the viral capsids. However, there are also striking differences between the three motors: they exhibit different DNA translocation rates, degrees of static and dynamic disorder, responses to load, and pausing and slipping dynamics.

  15. 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.

  16. Cellstat--A continuous culture system of a bacteriophage for the study of the mutation rate and the selection process at the DNA level

    Science.gov (United States)

    Husimi, Yuzuru; Nishigaki, Koichi; Kinoshita, Yasunori; Tanaka, Toyosuke

    1982-04-01

    A bacteriophage is continuously cultured in the flow of the host bacterial cell under the control of a minicomputer. In the culture, the population of the noninfected cell is kept constant by the endogeneous regulation mechanism, so it is called the ''cellstat'' culture. Due to the high dilution rate of the host cell, the mutant cell cannot be selected in the cellstat. Therefore, the cellstat is suitable for the study of the mutation rate and the selection process of a bacteriophage under well-defined environmental conditions (including physiological condition of the host cell) without being interfered by host-cell mutations. Applications to coliphage fd, a secretion type phage, are shown as a measurement example. A chimera between fd and a plasmid pBR322 is cultured more than 100 h. The process of population changeovers by deletion mutants indicates that the deletion hot spots exist in this cloning vector and that this apparatus can be used also for testing instability of a recombinant DNA.

  17. 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.

  18. 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

  19. Studies on the ability of irradiated Escherichia coli bacteria to reactivate X-ray inactivated bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Kiessling, W.

    1980-01-01

    The Weigle Reactivation phenomenon ie. the observation that low UV-flow irradiated bacteria increase the survival rate of UV-irradiated phages has not, to date, been studied with other forms of irradiation as inducers. In the studies reported here lambda-phages and E. coli cells in LB-medium were treated with X-rays. Host cells treated with an X-ray dose from 85 to 765 Gy showed a reactivation factor of 1.3 to 3.0 for X-ray inactivated phages. The capacity of the bacteria for phage reproduction did not appear to be markedly diminished. A reactivation factor of 1.3 only was found for X-irradiated phages when host cells were treated with UV-irradiation. The low Weigle reactivation of X-ray treated phages compared to UV-treatment was found to be due to a diminished absorption capacity, as demonstrated by the determination of free non-absorbed phages by filtration of radioactive-labelled phage-host-complexes. Reactivation studies on X-irradiated phages with various host bacteria of different radiation sensitivities confirm this finding.

  20. Emerging methods to study bacteriophage infection at the single-cell level.

    Science.gov (United States)

    Dang, Vinh T; Sullivan, Matthew B

    2014-01-01

    Bacteria and their viruses (phages) are abundant across diverse ecosystems and their interactions influence global biogeochemical cycles and incidence of disease. Problematically, both classical and metagenomic methods insufficiently assess the host specificity of phages and phage-host infection dynamics in nature. Here we review emerging methods to study phage-host interaction and infection dynamics with a focus on those that offer resolution at the single-cell level. These methods leverage ever-increasing sequence data to identify virus signals from single-cell amplified genome datasets or to produce primers/probes to target particular phage-bacteria pairs (digital PCR and phageFISH), even in complex communities. All three methods enable study of phage infection of uncultured bacteria from environmental samples, while the latter also discriminates between phage-host interaction outcomes (e.g., lytic, chronic, lysogenic) in model systems. Together these techniques enable quantitative, spatiotemporal studies of phage-bacteria interactions from environmental samples of any ecosystem, which will help elucidate and predict the ecological and evolutionary impacts of specific phage-host pairings in nature. PMID:25566233

  1. Emerging methods to study bacteriophage infection at the single-cell level

    Directory of Open Access Journals (Sweden)

    Vinh Toan Dang

    2014-12-01

    Full Text Available Bacteria and their viruses (phages are abundant across diverse ecosystems and their interactions influence global biogeochemical cycles and incidence of disease. Problematically, both classical and metagenomic methods insufficiently assess the host specificity of phages and phage–host infection dynamics in nature. Here we review emerging methods to study phage–host interaction and infection dynamics with a focus on those that offer resolution at the single-cell level. These methods leverage ever-increasing sequence data to identify virus signals from single-cell amplified genome (SAG datasets or to produce primers/probes to target particular phage– bacteria pairs (digital PCR and phageFISH, even in complex communities. All three methods enable study of phage infection of uncultured bacteria from environmental samples, while the latter also discriminates between phage–host interaction outcomes (e.g., lytic, chronic, lysogenic in model systems. Together these techniques enable quantitative, spatiotemporal studies of phage–bacteria interactions from environmental samples of any ecosystem, which will help elucidate and predict the ecological and evolutionary impacts of specific phage–host pairings in nature.

  2. Radiation biophysicl study of biological molecules. Progress report, February 1, 1975--June 30, 1976. [Fast electrons, gamma and uv radiation, Escherichia coli, T1 and lambda bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Fluke, D.J.

    1976-01-01

    Progress is reported on the following research projects: direct action target investigation of molecular weights of enzymes exposed to fast electrons; direct action gamma radiation dosimetry with T/sub 1/ bacteriophage; uv radiation sensitivity of T/sub 1/ bacteriophage on various host strains of E. coli; temperature dependence of uv radiation direct action on dry T/sub 1/ bacteriophage; investigation of light and temperature effects during incubation of T/sub 1/ bacteriophage exposed to fast electrons; test of superoxide anion as a radiation intermediate in cellular radiobiology; uv action spectra related to error-prone repair; uv-reactivation experiments with T/sub 1/ and lambda bacteriophages; and split-dose uv mutagenesis in E. coli. (HLW)

  3. 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...

  4. 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.

  5. 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.

  6. 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...

  7. 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

  8. 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.

  9. 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

  10. 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...

  11. 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.

  12. 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.

  13. 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

  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. Structure of the replicative form of bacteriophage φX174 : VI. Studies on alkali-denatured double-stranded φX DNA

    NARCIS (Netherlands)

    Pouwels, P.H.; Knijnenburg, C.M.; Rotterdam, J. van; Cohen, J.A.; Jansz, H.S.

    1968-01-01

    Double-stranded φX DNA which accumulates after infection with bacteriophage φX174 in the presence of chloramphenicol consists mainly of twisted circular double-stranded DNA with no single-strand breaks (component I) and of circular double-stranded DNA, in which single-strand breaks are present (comp

  16. 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...

  17. 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.

  18. 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.

  19. 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...

  20. 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

  1. Effects of pulling forces, osmotic pressure, condensing agents and viscosity on the thermodynamics and kinetics of DNA ejection from bacteriophages to bacterial cells: a computational study

    Science.gov (United States)

    Petrov, Anton S.; Douglas, Scott S.; Harvey, Stephen C.

    2013-03-01

    In this work, we report on simulations of double-stranded DNA (dsDNA) ejection from bacteriophage ϕ29 into a bacterial cell. The ejection was studied with a coarse-grained model, in which viral dsDNA was represented by beads on a torsion-less string. The bacteriophage’s capsid and the bacterial cell were defined by sets of spherical constraints. To account for the effects of the viscous medium inside the bacterial cell, the simulations were carried out using a Langevin dynamics protocol. Our simplest simulations (involving constant viscosity and no external biasing forces) produced results compatible with the push-pull model of DNA ejection, with an ejection rate significantly higher in the first part of ejection than in the latter parts. Additionally, we performed more complicated simulations, in which we included additional factors such as external forces, osmotic pressure, condensing agents and ejection-dependent viscosity. The effects of these factors (independently and in combination) on the thermodynamics and kinetics of DNA ejection were studied. We found that, in general, the dependence of ejection forces and ejection rates on the amount of DNA ejected becomes more complex if the ejection is modeled with a broader, more realistic set of parameters and influences (such as variation in the solvent’s viscosity and the application of an external force). However, certain combinations of factors and numerical parameters led to the opposition of some ejection-driving and ejection-inhibiting influences, ultimately causing an apparent simplification of the ejection profiles.

  2. 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.

  3. 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

  4. 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...

  5. 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...

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. [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

  14. 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

  15. 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.

  16. 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.

  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 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

  19. 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

  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. 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.

  2. 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

  3. Optical tweezers studies of viral DNA packaging: Motor function and DNA confinement in Bacteriophages phi29, lambda, and T4

    Science.gov (United States)

    Smith, Douglas

    2007-03-01

    In the assembly of many viruses a powerful molecular motor translocates the genome into a pre-assembled capsid. We use optical tweezers to directly measure translocation of a single DNA molecule into the viral capsid. Improved techniques allow us to measure initiation and early stages of packaging. With phi29 the DNA terminal protein was found to cause large variations in the starting point of packaging. Removal of this protein results in terminal initiation, permitting more accurate assessment of motor function and DNA confinement forces. We investigated the role of electrostatic repulsion by varying ionic screening of the DNA. The observed trends are in accord with those theoretically expected considering counter-ion competition; however the forces are larger than expected in comparison with recent theories and DNA ejection measurements. We have recently succeeded in extending our methods to study two other phages: lambda and T4. These systems have unique structural and functional features, presenting an opportunity for comparative studies in this family of molecular motors. Initial measurements show that lambda and T4 translocate DNA several times faster than the phi29 motor, but are more sensitive to applied load.

  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. 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...

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. STUDIES ON THE BACTERIOPHAGE OF D'HERELLE : VI. ON THE VIRULENCE OF THE OVERGROWTH IN THE LYSED CULTURES OF BACILLUS PESTIS CAVIAE (M. T. II).

    Science.gov (United States)

    Bronfenbrenner, J; Muckenfuss, R S; Korb, C

    1926-10-31

    Resistants isolated from the overgrowth of cultures of B. pestis caviae (M. T. II) lysed by various strains of specific bacteriophage proved to be avirulent when administered to mice by feeding, or by intraperitoneal injection. These cultures remained resistant to the action of bacteriophage so long as they were carried on agar. When transferred to broth, however, one group of resistants, namely, those isolated by means of "weak" phages, became susceptible to lysis after five to seven daily passages. The other group of resistants, isolated from the cultures lysed by one of the "strong" phages, failed to become susceptible to lysis even after nearly 200 passages in broth. Simultaneously with the recovery of susceptibility, the cultures of the first group regained a degree of virulence comparable to that of the parent culture of B. pestis caviae. The cultures of the second group of resistants have failed thus far to recover virulence (10 months after isolation). The latter cultures, apart from lack of both virulence and susceptibility to lysis, are identical with the parent culture of B. pestis caviae, as indicated by biochemical and antigenic properties. Our findings offer evidence in favor of the view that resistant strains result from selection among variants already existing in the parent culture and do not arise through the inheritance of specific immunity properties produced by the action of phage.

  11. [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.

  12. 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.

  13. 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.

  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. 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 ...

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. Biological Physics Prize talk: Grabbing the Cat by the Tail: Studies of DNA Packaging by Single φ 29 Bacteriophage Particles Using Optical Tweezers

    Science.gov (United States)

    Bustamante, Carlos

    2002-03-01

    I will present our recent results on the packaging of DNA by the connector motor at the base of the head of bacteriophage φ 29. As part of their infection cycle, many viruses must package their newly replicated genomes inside a protein capsid to insure its proper transport and delivery to other host cells. Bacteriophage φ 29 packages its 6.6 mm long double-stranded DNA into a 42 nm dia. x 54 nm high capsid via a portal complex that hydrolyses ATP. This process is remarkable because entropic, electrostatic, and bending energies of the DNA must be overcome to package the DNA to near-crystalline density. We have used optical tweezers to pull on single DNA molecules as they are packaged, thus demonstrating that the portal complex is a force generating motor. We find that this motor can work against loads of up to ~57 picoNewtons on average, making it one of the strongest molecular motors ever reported. Movements of over 5 mm are observed, indicating high processivity. Pauses and slips also occur, particularly at higher forces. We establish the force-velocity relationship of the motor and find that the rate-limiting step of the motor's cycle is force dependent even at low loads. Interestingly, the packaging rate decreases as the prohead is filled, indicating that an internal pressure builds up due to DNA compression. We estimate that at the end of the packaging the capsid pressure is ~15 MegaPascals, corresponding to an internal force of ~50 pN acting on the motor. The biological implications of this internal pressure and the mechano-chemical efficiency of the engine are discussed.

  3. 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.

  4. 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...

  5. 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...

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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...

  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. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. Detection and quantification of Flavobacterium psychrophilum specific bacteriophages in rainbow trout upon different administration methods: Implications for disease control in aquaculture

    DEFF Research Database (Denmark)

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

    2013-01-01

    , the use of lytic bacteriophages is a promising alternative approach to disease control in aquaculture. Bacteriophage control of bacterial infections depends on efficient delivery of the phages to the infected organs, and in this study we therefore examined the occurrence and persistence of phages...

  2. 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

  3. Studies on the repair of damaged DNA in bacteriophage, bacterial and mammalian systems. Comprehensive report, 1 February 1981-15 September 1983

    International Nuclear Information System (INIS)

    We have explored the molecular mechanism of the repair of DNA at a number of different levels of biological organization, by investigating bacteriophage, bacterial, yeast and mammalian (including human) cells. We have demonstrated that uv endonuclease of phage T4 not only possesses pyrimidine dimer (PD)-DNA glycosylase activity but also apyrimidinic (AP) endonuclease activity. The demonstration of both activities provided an explanation for the specific endonucleosytic cleavage of DNA at sites of pyrimidine dimers catalyzed by this small protein. A new apurinic/apyrimidinic (AP) endonuclease, specific for sites of of base loss in single stranded DNA has been isolated from E. celi and presumably recognizes these lesions in single stranded regions of duplex DNA. We have partially purified this enzyme and have carried out a preliminary characterization of the activity. We treated xeroderma pigmentosum and normal cells with sodium butyrate in the hope of restoring normal levels of excision repair to the former. Although this result was not obtained, we established that all cells treated with sodium butyrate show enhanced levels of repair synthesis, thus providing a means for increasing the sensitivity of this commonly used technique for measuring DNA repair in mammalian cells in culture

  4. 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

  5. qPCR (quantitative polymerase chain reaction) for the quantification of bacteriophages in stream water samples to investigate hydrological processes: a proof-of-concept study in the Huewelerbach experimental catchment (Luxembourg)

    Science.gov (United States)

    Antonelli, Marta; Narayanan Balasubramanian, Mukundh; Ogorzaly, Leslie; Pfister, Laurent

    2016-04-01

    Albeit recent technological developments (e.g. field deployable instruments operating at high temporal frequencies), experimental hydrology is a discipline that remains measurement limited. From this perspective, trans-disciplinary approaches may create valuable opportunities to enlarge the amount of tools available for investigating hydrological processes. Bacteriophages have been widely used in hydrology as biological tracer for investigating colloid transport and contamination of ground water systems. However, there are only a few studies focusing on the employability of bacteriophages as surface water tracers (i.e. phage transport, system functioning). Here, we present a proof-of-concept study carried out in the Huewelerbach catchment in Luxembourg in December 2015. The aim of this study was to investigate how viral particles can be used to detect hydrological connectivity between the riparian zone/river bank and the stream during rainfall events. Moreover, this study is one of the first attempts for applying the qPCR (quantitative polymerase chain reaction) technique for the quantification of bacteriophages in stream water samples to investigate hydrological processes. This technique is very sensitive and has a large dynamic range - enhancing ease and speed of phage detection. We used two different male-specific coliphages (GA phage, genogroup II and SP phage, genogroup IV). Two litres of GA phage were injected directly in the stream as a slug injection and two litres of SP phage were poured next to the river bank (alluvial deposition) close to the injection point. We also added NaCl (200 g) to both phage suspensions. We collected stream water samples 100 m and 500 m downstream (i.e. catchment outlet) of the injection point for one week. Phages were concentrated through ultracentrifugation of 100 ml of water sample followed by quantification via qPCR. Conductivity in stream water was monitored for the entire duration of the experiment. Discharge was monitored

  6. 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.

  7. 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...

  8. 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.

  9. 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

  10. 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

    terminase subunits confirms their packaging strategies and grouping to the different phage genus type. All these studies are necessary for the development and the use of an efficient cocktail with commercial applications in bacteriophage therapy against Salmonella.

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

    Directory of Open Access Journals (Sweden)

    Carlota eBardina

    2016-04-01

    analysis of large terminase subunits confirms their packaging strategies and grouping to the different phage genus type. All these studies are necessary for the development and the use of an efficient cocktail with commercial applications in bacteriophage therapy against Salmonella.

  12. 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...

  13. RNA and DNA bacteriophages as molecular diagnosis controls in clinical virology: a comprehensive study of more than 45,000 routine PCR tests.

    Directory of Open Access Journals (Sweden)

    Laetitia Ninove

    Full Text Available Real-time PCR techniques are now commonly used for the detection of viral genomes in various human specimens and require for validation both external and internal controls (ECs and ICs. In particular, ICs added to clinical samples are necessary to monitor the extraction, reverse transcription, and amplification steps in order to detect false-negative results resulting from PCR-inhibition or errors in the technical procedure. Here, we performed a large scale evaluation of the use of bacteriophages as ICs in routine molecular diagnosis. This allowed to propose simple standardized procedures (i to design specific ECs for both DNA and RNA viruses and (ii to use T4 (DNA or MS2 (RNA phages as ICs in routine diagnosis. Various technical formats for using phages as ICs were optimised and validated. Subsequently, T4 and MS2 ICs were evaluated in routine real-time PCR or RT-PCR virological diagnostic tests, using a series of 8,950 clinical samples (representing 36 distinct specimen types sent to our laboratory for the detection of a variety of DNA and RNA viruses. The frequency of inefficient detection of ICs was analyzed according to the nature of the sample. Inhibitors of enzymatic reactions were detected at high frequency in specific sample types such as heparinized blood and bone marrow (>70%, broncho-alveolar liquid (41% and stools (36%. The use of T4 and MS2 phages as ICs proved to be cost-effective, flexible and adaptable to various technical procedures of real-time PCR detection in virology. It represents a valuable strategy for enhancing the quality of routine molecular diagnosis in laboratories that use in-house designed diagnostic systems, which can conveniently be associated to the use of specific synthetic ECs. The high rate of inhibitors observed in a variety of specimen types should stimulate the elaboration of improved technical protocols for the extraction and amplification of nucleic acids.

  14. 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.

  15. Sequence variability of Campylobacter temperate bacteriophages

    Directory of Open Access Journals (Sweden)

    Ng Lai-King

    2008-03-01

    if they represented remnant prophage DNA in the bacterial chromosomes. Conclusion These putative prophages form a family of phages with conserved sequences, and appear to be adapted to Campylobacter. There was evidence for recombination among groups of prophages, suggesting that the prophages had a mosaic structure. In many of these properties, the Mu-like CMLP 1 homologs characterized in this study resemble temperate bacteriophages of enteric bacteria that are responsible for contributions to virulence and host adaptation.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  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. 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...

  4. 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.)

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Binding of the N-Terminal Domain of the Lactococcal Bacteriophage TP901-1 CI Repressor to Its Target DNA: A Crystallography, Small Angle Scattering, and Nuclear Magnetic Resonance Study

    DEFF Research Database (Denmark)

    Frandsen, Kristian Erik Høpfner; Rasmussen, Kim K.; Jensen, Malene Ringkjøbing;

    2013-01-01

    In most temperate bacteriophages, regulation of the choice of lysogenic or lytic life cycle is controlled by a CI repressor protein. Inhibition of transcription is dependent on a helix–turn–helix motif, often located in the N-terminal domain (NTD), which binds to specific DNA sequences (operator ...

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...

  13. 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...

  14. 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...

  15. 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

  16. Campylobacter jejuni acquire new host-derived CRISPR spacers when in association with bacteriophages harbouring a CRISPR-like Cas4 protein

    Directory of Open Access Journals (Sweden)

    Ian F. Connerton

    2015-01-01

    Full Text Available Campylobacter jejuni is a worldwide cause of human diarrhoeal disease. Clustered Repetitively Interspaced Palindromic Repeats (CRISPRs and associated proteins allow Bacteria and Archaea to evade bacteriophage and plasmid infection. Type II CRISPR systems are found in association with combinations of genes encoding the CRISPR-associated Cas1, Cas2, Cas4 or Csn2, and Cas9 proteins. C. jejuni possesses a minimal subtype II-C CRISPR system containing cas1, cas2, and cas9 genes whilst cas4 is notably absent. Cas4 proteins possess 5ʹ-3ʹ exonuclease activity to create recombinogenic-ends for spacer acquisition. Here we report a conserved Cas4-like protein in Campylobacter bacteriophages that creates a novel split arrangement between the bacteriophage and host that represents a new twist in the bacteriophage/host co-evolutionary arms race. The continuous association of bacteriophage and host in the carrier state life cycle of C. jejuni provided an opportunity to study spacer acquisition in this species. Remarkably all the spacer sequences observed were of host origin. We hypothesise that Campylobacter bacteriophages can use Cas4-like protein to activate spacer acquisition to use host DNA as an effective decoy to bacteriophage DNA. Bacteria that acquire self-spacers and escape phage infection must overcome CRISPR-mediated autoimmunity either by loss of the interference functions leaving them susceptible to foreign DNA incursion or tolerate changes in gene regulation.

  17. 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.

  18. 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

  19. 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

  20. 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

  1. Binding of the N-terminal domain of the lactococcal bacteriophage TP901-1 CI repressor to its target DNA: a crystallography, small angle scattering, and nuclear magnetic resonance study

    International Nuclear Information System (INIS)

    In most temperate bacteriophages, regulation of the choice of lysogenic or lytic life cycle is controlled by a CI repressor protein. Inhibition of transcription is dependent on a helix-turn-helix motif, often located in the N-terminal domain (NTD), which binds to specific DNA sequences (operator sites). Here the crystal structure of the NTD of the CI repressor from phage TP901-1 has been determined at 1.6 Angstroms resolution, and at 2.6 Angstroms resolution in complex with a 9 bp double-stranded DNA fragment that constitutes a half-site of the OL operator. This N-terminal construct, comprising residues 2-74 of the CI repressor, is monomeric in solution as shown by nuclear magnetic resonance (NMR), small angle X-ray scattering, and gel filtration and is monomeric in the crystal structures. The binding interface between the NTD and the half-site in the crystal is very similar to the interface that can be mapped by NMR in solution with a full palindromic site. The interactions seen in the complexes (in the crystal and in solution) explain the observed affinity for the OR site that is lower than that for the OL site and the specificity for the recognized DNA sequence in comparison to that for other repressors. Compared with many well-studied phage repressor systems, the NTD from TP901-1 CI has a longer extended scaffolding helix that, interestingly, is strongly conserved in putative repressors of Gram-positive pathogens. On the basis of sequence comparisons, we suggest that these bacteria also possess repressor/anti-repressor systems similar to that found in phage TP901-1. (authors)

  2. [Contemporary view on the role of bacteriophages in evolution of nosocomial strains and prophylaxis of healthcare associated infections].

    Science.gov (United States)

    Zueva, L P; Aslanov, B I; Akimkin, V G

    2014-01-01

    One of the actual problems of contemporary healthcare are healthcare associated infections (HAI). An important aspect of study of HAI problem is the study of evolution of hospital strains causing HAI. The knowledge accumulated to date in the field of bacteria genetics gives evidence on the significant role of phages in the mechanism of virulence obtaining by pathogenic and opportunistic microorganisms. The studies of the authors of this article show that bacteriophages may play a significant role in the formation of virulent properties in hospital conditions that in different hospitals with participation of phages form virulent and antibiotic resistant hospital strains of HAI causative agents. At the same time bacteriophages are effective means for HAI therapy and prophylaxis. Under the condition of mass and irrational use of antibiotics, HAI causative agents form multiple resistance to the existing antibacterial preparations. In this regard bacteriophages as antimicrobial agents become especially actual. To date in Russian and foreign literature considerable material has been accumulated that shows high effectiveness of bacteriophages under the conditions of rational use. The aim of this review is to evaluate contemporary achievements in the field of study of bacteriophage role in evolution of hospital strains and therapy and prophylaxis of healthcare associated infections.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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...

  9. 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.

  10. 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...

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. In vitro characterization and in vivo properties of Salmonellae lytic bacteriophages isolated from free-range layers

    Directory of Open Access Journals (Sweden)

    L Fiorentin

    2004-06-01

    Full Text Available Occurrence of food poisoning related to Salmonella-contaminated eggs and chicken meat has been frequent in humans. Salmonella Enteritidis (SE and Salmonella Typhimurium (ST are included among the most important paratyphoid salmonellae associated with chicken meat and eggs. Elimination of Salmonella at the pre-harvest stage can play a significant role in preventing the introduction of this pathogen into the food chain and consequently in the reduction of food poisoning in humans. Bactericidal bacteriophages may provide a natural, nontoxic, feasible and non-expensive component of the multi-factorial approach for a pre-harvest control of Salmonella in poultry. Five bacteriophages lytic for SE PT4 and ST were obtained from 107 samples of feces of free-range layers in Brazil. All bacteriophages were characterized in vitro and in vivo, showing head and tail morphology and dsDNA as nucleic acids. Results of "in vivo" studies suggested that bacteriophages do not remain in Salmonella-free birds longer than one day, whereas they multiply in Salmonella-infected birds for longer periods. Besides, selection for phage-resistant SE PT4 did not seem to occur in the short term. Isolated bacteriophages will be investigated for their potential for pre-harvest biocontrol of SE PT4 in poultry.

  18. Metabolic responses to Lactobacillus plantarum contamination or bacteriophage treatment in Saccharomyces cerevisiae using a GC-MS-based metabolomics approach.

    Science.gov (United States)

    Cui, Feng-Xia; Zhang, Rui-Min; Liu, Hua-Qing; Wang, Yan-Feng; Li, Hao

    2015-12-01

    Bacteriophage can be used as a potential alternative agent for controlling Lactobacillus plantarum contamination during bioethanol production. However, how Saccharomyces cerevisiae respond against contaminative L. plantarum or added bacteriophage remains to be fully understood. In this study, gas chromatography-mass spectrometry and a multivariate analysis were employed to investigate the intracellular biochemical changes in S. cerevisiae cells that were elicited by L. plantarum contamination or bacteriophage treatment. The intracellular metabolite profiles originating from different groups were unique and could be distinguished with the aid of principal component analysis. Moreover, partial least-squares-discriminant analysis revealed a group classification and pairwise discrimination, and 13 differential metabolites with variable importance in the projection value greater than 1 were identified. The metabolic relevance of these compounds in the response of S. cerevisiae to L. plantarum contamination or bacteriophage treatment was discussed. Besides generating lactic acid and competing for nutrients or living space, L. plantarum contamination might also inhibit the growth of S. cerevisiae through regulating the glycolysis in S. cerevisiae. Moreover, increased concentrations of monounsaturated fatty acids secondary to bacteriophage treatment might lead to more membrane fluidity and promote the cell viability of S. cerevisiae.

  19. Back to the future: evolving bacteriophages to increase their effectiveness against the pathogen Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Betts, Alex; Vasse, Marie; Kaltz, Oliver; Hochberg, Michael E

    2013-11-01

    Antibiotic resistance is becoming increasingly problematic for the treatment of infectious disease in both humans and livestock. The bacterium Pseudomonas aeruginosa is often found to be resistant to multiple antibiotics and causes high patient mortality in hospitals. Bacteriophages represent a potential option to combat pathogenic bacteria through their application in phage therapy. Here, we capitalize on previous studies showing how evolution may increase phage infection capacity relative to ancestral genotypes. We passaged four different phage isolates (podoviridae, myoviridae) through six serial transfers on the ancestral strain of Pseudomonas aeruginosa PAO1. We first demonstrate that repeated serial passage on ancestral bacteria increases infection capacity of bacteriophage on ancestral hosts and on those evolved for one transfer. This result is confirmed when examining the ability of evolved phage to reduce ancestral host population sizes. Second, through interaction with a single bacteriophage for 24 h, P. aeruginosa can evolve resistance to the ancestor of that bacteriophage; this also provides these evolved bacteria with cross-resistance to the other three bacteriophages. We discuss how the evolutionary training of phages could be employed as effective means of combatting bacterial infections or disinfecting surfaces in hospital settings, with reduced risk of bacterial resistance compared with conventional methods. PMID:24187587

  20. 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

  1. 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...

  2. 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."

  3. 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. 

  4. 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.

  5. 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.

  6. 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}.

  7. 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

  8. 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.

  9. 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.

  10. 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...

  11. 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

  12. Variation of resistance and infectivity between Pseudomonas fluorescens SBW25 and bacteriophage Ф2 and its therapeutic implications

    Institute of Scientific and Technical Information of China (English)

    Hanchen; Chen; Guohua; Chen

    2015-01-01

    <正>Dear Editor,Studies of the coevolutionary dynamics between Pseudomonas fluorescens SBW25 and bacteriophageФ2 can explore host resistance and parasite infectivity with applications in the ecological and therapeutic fields.Coevolutionary dynamics determine the efficacy of phage-based therapy.In the study described here,bacterial resistance and phage infectivity fluctuated with culture

  13. 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

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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

  19. Development of prototypes of bioactive packaging materials based on immobilized bacteriophages for control of growth of bacterial pathogens in foods.

    Science.gov (United States)

    Lone, Ayesha; Anany, Hany; Hakeem, Mohammed; Aguis, Louise; Avdjian, Anne-Claire; Bouget, Marina; Atashi, Arash; Brovko, Luba; Rochefort, Dominic; Griffiths, Mansel W

    2016-01-18

    Due to lack of adequate control methods to prevent contamination in fresh produce and growing consumer demand for natural products, the use of bacteriophages has emerged as a promising approach to enhance safety of these foods. This study sought to control Listeria monocytogenes in cantaloupes and RTE meat and Escherichia coli O104:H4 in alfalfa seeds and sprouts under different storage conditions by using specific lytic bacteriophage cocktails applied either free or immobilized. Bacteriophage cocktails were introduced into prototypes of packaging materials using different techniques: i) immobilizing on positively charged modified cellulose membranes, ii) impregnating paper with bacteriophage suspension, and iii) encapsulating in alginate beads followed by application of beads onto the paper. Phage-treated and non-treated samples were stored for various times and at temperatures of 4°C, 12°C or 25°C. In cantaloupe, when free phage cocktail was added, L. monocytogenes counts dropped below the detection limit of the plating technique (<1 log CFU/g) after 5 days of storage at both 4°C and 12°C. However, at 25°C, counts below the detection limit were observed after 3 and 6h and a 2-log CFU/g reduction in cell numbers was seen after 24h. For the immobilized Listeria phage cocktail, around 1-log CFU/g reduction in the Listeria count was observed by the end of the storage period for all tested storage temperatures. For the alfalfa seeds and sprouts, regardless of the type of phage application technique (spraying of free phage suspension, bringing in contact with bacteriophage-based materials (paper coated with encapsulated bacteriophage or impregnated with bacteriophage suspension)), the count of E. coli O104:H4 was below the detection limit (<1 log CFU/g) after 1h in seeds and about a 1-log cycle reduction in E. coli count was observed on the germinated sprouts by day 5. In ready-to-eat (RTE) meat, LISTEX™ P100, a commercial phage product, was able to

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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 ...

  5. 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...

  6. 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,...

  7. 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...

  8. 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...

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Discrimination of bacteriophage infected cells using locked nucleic acid fluorescent in situ hybridization (LNA-FISH).

    Science.gov (United States)

    Vilas Boas, Diana; Almeida, Carina; Sillankorva, Sanna; Nicolau, Ana; Azeredo, Joana; Azevedo, Nuno F

    2016-01-01

    Bacteriophage-host interaction studies in biofilm structures are still challenging due to the technical limitations of traditional methods. The aim of this study was to provide a direct fluorescence in situ hybridization (FISH) method based on locked nucleic acid (LNA) probes, which targets the phage replication phase, allowing the study of population dynamics during infection. Bacteriophages specific for two biofilm-forming bacteria, Pseudomonas aeruginosa and Acinetobacter, were selected. Four LNA probes were designed and optimized for phage-specific detection and for bacterial counterstaining. To validate the method, LNA-FISH counts were compared with the traditional plaque forming unit (PFU) technique. To visualize the progression of phage infection within a biofilm, colony-biofilms were formed and infected with bacteriophages. A good correlation (r = 0.707) was observed between LNA-FISH and PFU techniques. In biofilm structures, LNA-FISH provided a good discrimination of the infected cells and also allowed the assessment of the spatial distribution of infected and non-infected populations.

  17. 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 ...

  18. 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.

  19. 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.

  20. 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...

  1. 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

  2. Response of bacteriophage T7 biological dosimeter to dehydration and extraterrestrial solar UV radiation

    Science.gov (United States)

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

    2007-02-01

    The experiment "Phage and uracil response" (PUR) will be accommodated in the EXPOSE facility of the ISS. Bacteriophage T7/isolated T7 DNA will be exposed to different subsets of extreme environmental parameters in space, in order to study the Responses of Organisms to the Space Environment (ROSE). Launch into orbit is preceded by EXPOSE Experiment Verification Tests (EVT) to optimize the methods and the evaluation. Bacteriophage T7/isolated T7 DNA thin layers were exposed to vacuum ( 10-6Pa), to monochromatic (254 nm) and polychromatic (200-400 nm) UV radiation in air as well as in simulated space vacuum. Using neutral density (ND) filters dose-effect curves were performed in order to define the maximum doses tolerated. The effect of temperature fluctuation in vacuum was also studied. The structural/chemical effects on bacteriophage T7/isolated T7 DNA were analyzed by spectroscopic and microscopical methods. Characteristic changes in the absorption spectrum and in the electrophoretic pattern of phage/DNA have been detected indicating the damage of isolated and intraphage DNA. DNA damage was also determined by quantitative PCR (QPCR) using 555 and 3826 bp fragments of T7 DNA. We obtained substantial evidence that DNA lesions (e.g. strand breaks, DNA-protein cross-links, cyclobutane pirimidine dimers (CPDs) etc.) accumulate throughout exposure. Preliminary results suggest a synergistic action of space vacuum and UV radiation with DNA being the critical target.

  3. 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

  4. 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

  5. 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...

  6. 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...

  7. 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...

  8. 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.

  9. The possible use of V. parahaemolyticus - specific bacteriophages for prevention and therapy of infections caused by V. parahaemolyticus.

    Science.gov (United States)

    Tskhvediani, A; Khukhunashvili, T; Eliashvili, T; Tsertsvadze, G; Gachechiladze, N; Tediashvili, M

    2014-06-01

    Vibrio parahaemolyticus is the most common halophilic Vibrio species causing serious gastroenteritis in humans. The main source of infection is consumption of undercooked or raw seafood or exposure to contaminated water. The monitoring conducted in 2006-2008 demonstrated that warm, subtropical climate and low- to moderate salinity of water in the Black Sea coastal zone provides a favorable environment for growth and spread of V. parahaemolyticus bacteria. Antibiotics are commonly applied for control V.parahaemolyticus infections in humans. However, with the growing problem with bacterial antibiotic-resistance search for alternative biological anti-infectives, such as bacteriophages, becomes more actual. The aim of the presented work was characterization of V. parahamolyticus- specific bacteriophages in relation with their possible use for treatment and prevention of food and waterborne gastroenteritis in humans infected with V.parahaemolyticus. 69 bacteriophages specific to V.parahaemolyticus were isolated from different water sources and 5 of them were characterized according to their virion morphology, host-range, temperature and pH dependence. Stability of phages in different media and solutions, also susceptibility to action of a number of protolithic enzymes was studied as well. Obtained results showed that studied bacteriophages can be used for preparation of phage mixture as a potential therapeutic preparation against V.parahaemolyticus associated infections.

  10. Damages of Biological Components in Bacteria and Bacteriophages Exposed to Atmospheric Non-thermal Plasma

    Science.gov (United States)

    Mizuno, Akira; Yasuda, Hachiro

    Mechanism of inactivation of bio-particles exposed to dielectric barrier discharge, DBD, has been studied using E. coli and bacteriophages. States of different biological components were monitored during the course of inactivation. Analysis of green fluorescent protein, GFP, introduced into E.coli cells proved that Non-thermal Plasma, NTP causes a prominent protein damages without cutting peptide bonds. We have developed a biological assay which evaluates in vitro DNA damage of the bacteriophages. Bacteriophage λ having double stranded DNA was exposed to DBD, then DNA was purified and subjected to in vitro DNA packaging reactions. The re-packaged phages consist of the DNA from discharged phages and brand-new coat proteins. Survival curves of the re-packaged phages showed extremely large D value (D = 25 s) compared to the previous D value (D = 3 s) from the discharged phages. The results indicate that DNA damage hardly contributed to the inactivation, and the damage in coat proteins is responsible for inactivation of the phages. M13 phages having single stranded DNA were also examined with the same manner. In this case, damage to DNA was as severe as that of the coat proteins.

  11. Characterization of a novel Morganella morganii bacteriophage FSP1 isolated from river water.

    Science.gov (United States)

    Yamaki, Shogo; Omachi, Takuo; Kawai, Yuji; Yamazaki, Koji

    2014-10-01

    Morganella morganii has been identified as a causative agent of opportunistic infections and histamine poisoning. Bacteriophage is a virus and has recently been considered an alternative agent to antibiotics for the control of bacteria that have developed antibiotic resistance. In this study, a novel M. morganii bacteriophage isolated from river water was characterized. The isolated phage, termed FSP1, was purified by polyethylene glycol precipitation followed by cesium chloride density-gradient centrifugation. FSP1 has infectivity against only M. morganii and was identified as a Myoviridae bacteriophage through morphological analysis with transmission electron microscopy. According to the one-step growth curve, the FSP1 latent period, eclipse period, and burst size were 30, 20 min, and 42 PFU infected cell(-1) , respectively. The genome size of FSP1 was estimated to be c. 45.6-49.4 kb by restriction endonuclease analyses. Moreover, challenge testing against M. morganii in vitro revealed that FSP1 had high lytic activity and that the viable cell count of M. morganii was reduced by 6.12 log CFU mL(-1) after inoculation with FSP1 at a multiplicity of infection (MOI) = 10. These results suggested that FSP1 could be used as a biocontrol agent against M. morganii for treatment of infectious disease treatment or food decontamination.

  12. The diversity and host interactions of Propionibacterium acnes bacteriophages on human skin.

    Science.gov (United States)

    Liu, Jared; Yan, Riceley; Zhong, Qiao; Ngo, Sam; Bangayan, Nathanael J; Nguyen, Lin; Lui, Timothy; Liu, Minghsun; Erfe, Marie C; Craft, Noah; Tomida, Shuta; Li, Huiying

    2015-09-01

    The viral population, including bacteriophages, is an important component of the human microbiota, yet is poorly understood. We aim to determine whether bacteriophages modulate the composition of the bacterial populations, thus potentially playing a role in health or disease. We investigated the diversity and host interactions of the bacteriophages of Propionibacterium acnes, a major human skin commensal implicated in acne pathogenesis. By sequencing 48 P. acnes phages isolated from acne patients and healthy individuals and by analyzing the P. acnes phage populations in healthy skin metagenomes, we revealed that P. acnes phage populations in the skin microbial community are often dominated by one strain. We also found phage strains shared among both related and unrelated individuals, suggesting that a pool of common phages exists in the human population and that transmission of phages may occur between individuals. To better understand the bacterium-phage interactions in the skin microbiota, we determined the outcomes of 74 genetically defined Propionibacterium strains challenged by 15 sequenced phages. Depending on the Propionibacterium lineage, phage infection can result in lysis, pseudolysogeny, or resistance. In type II P. acnes strains, we found that encoding matching clustered regularly interspaced short palindromic repeat spacers is insufficient to confer phage resistance. Overall, our findings suggest that the prey-predator relationship between bacteria and phages may have a role in modulating the composition of the microbiota. Our study also suggests that the microbiome structure of an individual may be an important factor in the design of phage-based therapy.

  13. 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.

  14. Direct Quantitative Detection and Identification of Lactococcal Bacteriophages from Milk and Whey by Real-Time PCR: Application for the Detection of Lactococcal Bacteriophages in Goat's Raw Milk Whey in France

    Directory of Open Access Journals (Sweden)

    Mai Huong Ly-Chatain

    2011-01-01

    Full Text Available The presence of Lactococcus bacteriophages in milk can partly or completely inhibit milk fermentation. To prevent the problems associated with the bacteriophages, the real-time PCR was developed in this study for direct detection from whey and milk of three main groups of Lactococcus bacteriophages, c2, 936, and P335. The optimization of DNA extraction protocol from complex matrices such as whey and milk was optimized allowed the amplification of PCR without any matrix and nontarget contaminant interference. The real-time PCR program was specific and with the detection limit of 102 PFU/mL. The curve slopes were −3.49, −3.69, and −3.45 with the amplification efficiency estimated at 94%, 94%, and 98% and the correlation coefficient (2 of 0.999, 0.999, and 0.998 for c2, 936 and P335 group, respectively. This method was then used to detect the bacteriophages in whey and goat's raw milk coming from three farms located in the Rhône-Alpes region (France.

  15. 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.

  16. In vitro assessment of the susceptibility of planktonic and attached cells of foodborne pathogens to bacteriophage p22-mediated salmonella lysates.

    Science.gov (United States)

    Ahn, Juhee; Kim, Songrae; Jung, Lae-Seung; Biswas, Debabrata

    2013-12-01

    This study was designed to evaluate the lytic activity of bacteriophage P22 against Salmonella Typhimurium ATCC 19585 (Salmonella Typhimurium P22(-)) at various multiplicities of infections (MOIs), the susceptibility of preattached Salmonella cells against bacteriophage P22, and the effect of P22-mediated bacterial lysates (extracellular DNA) on the attachment ability of Listeria monocytogenes ATCC 7644 and enterohemorrhagic Escherichia coli ATCC 700927 to surfaces. The numbers of attached Salmonella Typhimurium P22(-) cells were effectively reduced to below the detection limit (1 log CFU/ml) at the fixed inoculum levels of 3 × 10(-) CFU/ml (MOI = 3.12) and 3 × 10(3) CFU/ml (MOI = 4.12) by bacteriophage P22. The attached Salmonella Typhimurium P22(-) cells remained more than 2 log CFU/ml, with increasing inoculum levels from 3 × 10(4) to 3 × 10(7) CFU/ml infected with 4 × 10(8) PFU/ml of P22. The number of preattached Salmonella Typhimurium P22(-) cells was noticeably reduced by 2.72 log in the presence of P22. The highest specific attachment ability values for Salmonella Typhimurium P22(-), Salmonella Typhimurium ATCC 23555 carrying P22 prophage (Salmonella Typhimurium P22(+)), L. monocytogenes, and enterohemorrhagic E. coli were 2.09, 1.06, 1.86, and 1.08, respectively, in the bacteriophage-mediated cell-free supernatants (CFS) containing high amounts of extracellular DNA. These results suggest that bacteriophages could potentially be used to effectively eliminate planktonic and preattached Salmonella Typhimurium P22(-) cells with increasing MOI. However, further research is needed to understand the role of bacteriophage-induced lysates in bacterial attachment, which can provide useful information for the therapeutic use of bacteriophage in the food system.

  17. Isolation and characterization of bacteriophages infecting Xanthomonas arboricola pv. juglandis, the causal agent of walnut blight disease.

    Science.gov (United States)

    Romero-Suarez, Sandra; Jordan, Brian; Heinemann, Jack A

    2012-05-01

    Walnut orchards suffer from a blight caused by the bacteria Xanthomonas arboricola pv. juglandis. These bacteria can be infected by viral bacteriophages and this study was carried out to isolate and characterize bacteriophages from walnut orchards located throughout the South Island of New Zealand. Twenty six X. arboricola phages were isolated from three hundred and twenty six samples of plant material representing phyllosphere and rhizosphere ecosystems. The phage isolates were characterized by host-range, plaque and particle morphology, restriction digest and phylogenetic analysis and stability under various storage conditions. From capsid and tail dimensions the bacteriophages were considered to belong to the double-stranded DNA families Podoviridae and Siphoviridae. Of the twenty six bacteriophages, sixteen belonged to Podoviridae and were found both in the phyllosphere and rhizosphere. In contrast, Siphoviridae were present only in the rhizosphere isolates. Phage genome sizes ranged from 38.0 to 52.0 kb from a Hind III restriction digestion and had in common a 400 kb fragment that was identical at the DNA level. Despite the similar restriction patterns, maximum parsimony bootstrap analysis showed that the phage were members of different groups. Finally, we hypothesise that these phage might have use in a biocontrol strategy and therefore storage stability and efficacy was tested. Titres declined more than 50% over a 12-months storage period. Deep-freezing temperatures (-34°C) increased while chloroform decreased the stability.

  18. RGD peptide-displaying M13 bacteriophage/PLGA nanofibers as cell-adhesive matrices for smooth muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Yong Cheol; Lee, Jong Ho; Jin, Oh Seong; Lee, Eun Ji; Jin, Lin Hua; Kim, Chang Seok; Hong, Suck Won; Han, Dong Wook; Kim, Chun Tae; Oh, Jin Woo [Pusan National University, Busan (Korea, Republic of)

    2015-01-15

    Extracellular matrices (ECMs) are network structures that play an essential role in regulating cellular growth and differentiation. In this study, novel nanofibrous matrices were fabricated by electrospinning M13 bacteriophage and poly(lactic-co-glycolic acid) (PLGA) and were shown to be structurally and functionally similar to natural ECMs. A genetically-engineered M13 bacteriophage was constructed to display Arg-Gly-Asp (RGD) peptides on its surface. The physicochemical properties of RGD peptide-displaying M13 bacteriophage (RGD-M13 phage)/PLGA nanofibers were characterized by using scanning electron microscopy and Fourier-transform infrared spectroscopy. We used immunofluorescence staining to confirm that M13 bacteriophages were homogenously distributed in RGD-M13 phage/PLGA matrices. Furthermore, RGD-M13 phage/PLGA nanofibrous matrices, having excellent biocompatibility, can enhance the behaviors of vascular smooth muscle cells. This result suggests that RGD-M13 phage/PLGA nanofibrous matrices have potentials to serve as tissue engineering scaffolds.

  19. ppGpp-dependent negative control of DNA replication of Shiga toxin-converting bacteriophages in Escherichia coli.

    Science.gov (United States)

    Nowicki, Dariusz; Kobiela, Wioletta; Węgrzyn, Alicja; Wegrzyn, Grzegorz; Szalewska-Pałasz, Agnieszka

    2013-11-01

    The pathogenicity of enterohemorrhagic Escherichia coli (EHEC) strains depends on the production of Shiga toxins that are encoded on lambdoid prophages. Effective production of these toxins requires prophage induction and subsequent phage replication. Previous reports indicated that lytic development of Shiga toxin-converting bacteriophages is inhibited in amino acid-starved bacteria. However, those studies demonstrated that inhibition of both phage-derived plasmid replication and production of progeny virions occurred during the stringent as well as the relaxed response to amino acid starvation, i.e., in the presence as well as the absence of high levels of ppGpp, an alarmone of the stringent response. Therefore, we asked whether ppGpp influences DNA replication and lytic development of Shiga toxin-converting bacteriophages. Lytic development of 5 such bacteriophages was tested in an E. coli wild-type strain and an isogenic mutant that does not produce ppGpp (ppGpp(0)). In the absence of ppGpp, production of progeny phages was significantly (in the range of an order of magnitude) more efficient than in wild-type cells. Such effects were observed in infected bacteria as well as after prophage induction. All tested bacteriophages formed considerably larger plaques on lawns formed by ppGpp(0) bacteria than on those formed by wild-type E. coli. The efficiency of synthesis of phage DNA and relative amount of lambdoid plasmid DNA were increased in cells devoid of ppGpp relative to bacteria containing a basal level of this nucleotide. We conclude that ppGpp negatively influences the lytic development of Shiga toxin-converting bacteriophages and that phage DNA replication efficiency is limited by the stringent control alarmone.

  20. Structural evolution of the P22-like phages: Comparison of Sf6 and P22 procapsid and virion architectures

    OpenAIRE

    Parent, Kristin N.; Gilcrease, Eddie B.; Casjens, Sherwood R.; Timothy S. Baker

    2012-01-01

    The coat proteins in tailed, dsDNA phage and in herpesviruses include a conserved core, similar to the bacteriophage HK97 subunit. Additions to the HK97 core often include Ig-like domains, such as the telokin-domain in P22. Eighty-six P22-like phages and prophages share a similar set of virion assembly genes and, based on comparisons of the thirteen viral assembly proteins, these phages are classified into three groups (P22-like, Sf6-like, and CUS-3-like). We used cryo-electron microscopy and...

  1. Vibrio parahaemolyticus and its specific bacteriophages as an indicator in cockles (Anadara granosa) for the risk of V. parahaemolyticus infection in Southern Thailand.

    Science.gov (United States)

    Yingkajorn, Mingkwan; Sermwitayawong, Natthawan; Palittapongarnpimp, Prasit; Nishibuchi, Mitsuaki; Robins, William P; Mekalanos, John J; Vuddhakul, Varaporn

    2014-05-01

    Correlation between the numbers of Vibrio parahaemolyticus and its specific bacteriophages in cockles was investigated from June 2009 to May 2010 in Hat Yai, Songkhla, Thailand. Cockles obtained monthly from a local market were sampled to determine the numbers of V. parahaemolyticus and bacteriophages that could form plaques on ten strains of pandemic and nonpandemic V. parahaemolyticus. In addition, V. parahaemolyticus isolates from clinical samples from Hat Yai hospital over the same period were investigated. All 139 cockles sampled were positive for V. parahaemolyticus. However, only 76 of them were positive for bacteriophages. During the testing period, the number of bacteriophages was not significantly correlated with the incidence of V. parahaemolyticus-infected patients, but the numbers of V. parahaemolyticus isolates from the cockle samples were closely related to the number of infected patients. The bacteriophages isolated from V. parahaemolyticus also infected Vibrio alginolyticus and Vibrio mimicus, suggesting that the broad host range of phages may be a factor of providing the possibility of their participation in the processes of genetic exchange between V. parahaemolyticus and closely related Vibrio spp. In conclusion, this study indicated that the number of V. parahaemolyticus in cockles may be a useful tool for predicting the relative risk of infection by V. parahaemolyticus in this area of Thailand.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Two-site kinetic modeling of bacteriophages transport through columns of saturated dune sand.

    Science.gov (United States)

    Schijven, Jack F; Hassanizadeh, S Majid; de Bruin, Ria H A M

    2002-08-01

    Breakthrough curves, on a semi-log scale, from tests in porous media with block-input of viruses, bacteria, protozoa and colloidal particles often exhibit a typical skewness: a rather slowly rising limb and a smooth transition of a declining limb to a very long tail. One-site kinetic models fail to fit the rising and declining limbs together with the tail satisfactorily. Inclusion of an equilibrium adsorption site does not seem to improve simulation results. This was encountered in the simulation of breakthrough curves from a recent field study on the removal of bacteriophages MS2 and PRD1 by passage through dune sand. In the present study, results of laboratory experiments for the study of this issue are presented. Breakthrough curves of salt and bacteriophages MS2, PRDI, and phiX174 in 1 D column experiments have been measured. One- and two-site kinetic models have been applied to fit and predict breakthrough curves from column experiments. The two-site model fitted all breakthrough curves very satisfactorily, accounting for the skewness of the rising limb as well as for the smooth transition of the declining limb to the tail of the breakthrough curve. The one-site model does not follow the curvature of the breakthrough tail, leading to an overestimation of the inactivation rate coefficient for attached viruses. Interaction with kinetic site 1 is characterized by relatively fast attachment and slow detachment, whereas attachment to and detachment from kinetic site 2 is fast. Inactivation of viruses and interaction with kinetic site 2 provide only a minor contribution to removal. Virus removal is mainly determined by the attachment to site 1. Bacteriophage phiX174 attached more than MS2 and PRD1, which can be explained by the greater electrostatic repulsion that MS2 and PRD1 experience compared to the less negatively charged phiX174. PMID:12180812

  4. 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

  5. Novel application of bacteriophage for controlling foaming in wastewater treatment plant- an eco-friendly approach.

    Science.gov (United States)

    Khairnar, Krishna; Chandekar, Rajshree; Nair, Aparna; Pal, Preeti; Paunikar, Waman N

    2016-01-01

    This addendum to "Novel application of bacteriophage for controlling foaming in wastewater treatment plant- an eco-friendly approach " includes characteristics of the phages NOC1, NOC2 and NOC3 not discussed in the previous paper. The phage adsorption and host interaction properties, their sensitivity to pH and temperature are inferred. NOC2 is seen to be more temperature resistant while others are not. All the phages show pH sensitivity. There is a variance observed in the behavior of these phages. Also, applicability of the phage based system to large scale reactors is studied and discussed here. PMID:26890996

  6. Isolation of Acanthamoeba-Specific Antibodies from a Bacteriophage Display Library

    Science.gov (United States)

    Khan, Naveed A.; Greenman, John; Topping, Katherine P.; Hough, Victoria C.; 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 by enzyme-linked immunosorbent assay, flow cytometry, and immunofluorescence. Four antibody clones that specifically bind to Acanthamoeba spp. were identified. PMID:10835006

  7. Novel application of bacteriophage for controlling foaming in wastewater treatment plant- an eco-friendly approach.

    Science.gov (United States)

    Khairnar, Krishna; Chandekar, Rajshree; Nair, Aparna; Pal, Preeti; Paunikar, Waman N

    2016-01-01

    This addendum to "Novel application of bacteriophage for controlling foaming in wastewater treatment plant- an eco-friendly approach " includes characteristics of the phages NOC1, NOC2 and NOC3 not discussed in the previous paper. The phage adsorption and host interaction properties, their sensitivity to pH and temperature are inferred. NOC2 is seen to be more temperature resistant while others are not. All the phages show pH sensitivity. There is a variance observed in the behavior of these phages. Also, applicability of the phage based system to large scale reactors is studied and discussed here.

  8. Cooperativity Leads to Temporally-Correlated Fluctuations in the Bacteriophage Lambda Genetic Switch

    Directory of Open Access Journals (Sweden)

    Jacob Quinn Shenker

    2015-04-01

    Full Text Available Cooperative interactions are widespread in biochemical networks, providing the nonlinear response that underlies behavior such as ultrasensitivity and robust switching. We introduce a temporal correlation function—the conditional activity—to study the behavior of these phenomena. Applying it to the bistable genetic switch in bacteriophage lambda, we find that cooperative binding between binding sites on the prophage DNA lead to non-Markovian behavior, as quantified by the conditional activity. Previously, the conditional activity has been used to predict allosteric pathways in proteins; here, we show that it identifies the rare unbinding events which underlie induction from lysogeny to lysis.

  9. Persistence of naturally occurring antibiotic resistance genes in the bacteria and bacteriophage fractions of wastewater.

    Science.gov (United States)

    Calero-Cáceres, William; Muniesa, Maite

    2016-05-15

    The emergence and prevalence of antibiotic resistance genes (ARGs) in the environment is a serious global health concern. ARGs from bacteria can be mobilized by mobile genetic elements, and recent studies indicate that phages and phage-derived particles, among others, could play a role in the spread of ARGs through the environment. ARGs are abundant in the bacterial and bacteriophage fractions of water bodies and for successful transfer of the ARGs, their persistence in these environments is crucial. In this study, three ARGs (blaTEM, blaCTX-M and sul1) that naturally occur in the bacterial and phage fractions of raw wastewater were used to evaluate the persistence of ARGs at different temperatures (4 °C, 22 °C and 37 °C) and pH values (3, 7 and 9), as well as after various disinfection treatments (thermal treatment, chlorination and UV) and natural inactivation in a mesocosm. Gene copies (GC) were quantified by qPCR; then the logarithmic reduction and significance of the differences between their numbers were evaluated. The ARGs persisted for a long time with minimal reductions after all the treatments. In general, they showed greater persistence in the bacteriophage fraction than in the bacterial fraction. Comparisons showed that the ARGs persisted under conditions that reduced culturable Escherichia coli and infectious coliphages below the limit of detection. The prevalence of ARGs, particularly in the bacteriophage fraction, poses the threat of the spread of ARGs and their incorporation into a new bacterial background that could lead to the emergence of new resistant clones. PMID:26978717

  10. Persistence of naturally occurring antibiotic resistance genes in the bacteria and bacteriophage fractions of wastewater.

    Science.gov (United States)

    Calero-Cáceres, William; Muniesa, Maite

    2016-05-15

    The emergence and prevalence of antibiotic resistance genes (ARGs) in the environment is a serious global health concern. ARGs from bacteria can be mobilized by mobile genetic elements, and recent studies indicate that phages and phage-derived particles, among others, could play a role in the spread of ARGs through the environment. ARGs are abundant in the bacterial and bacteriophage fractions of water bodies and for successful transfer of the ARGs, their persistence in these environments is crucial. In this study, three ARGs (blaTEM, blaCTX-M and sul1) that naturally occur in the bacterial and phage fractions of raw wastewater were used to evaluate the persistence of ARGs at different temperatures (4 °C, 22 °C and 37 °C) and pH values (3, 7 and 9), as well as after various disinfection treatments (thermal treatment, chlorination and UV) and natural inactivation in a mesocosm. Gene copies (GC) were quantified by qPCR; then the logarithmic reduction and significance of the differences between their numbers were evaluated. The ARGs persisted for a long time with minimal reductions after all the treatments. In general, they showed greater persistence in the bacteriophage fraction than in the bacterial fraction. Comparisons showed that the ARGs persisted under conditions that reduced culturable Escherichia coli and infectious coliphages below the limit of detection. The prevalence of ARGs, particularly in the bacteriophage fraction, poses the threat of the spread of ARGs and their incorporation into a new bacterial background that could lead to the emergence of new resistant clones.

  11. Genetic effects of cosmic radiation on bacteriophage T4Br/+/ /On materials of biological experiment Soyuz-Apollo/

    Energy Technology Data Exchange (ETDEWEB)

    Iurov, S.S. (Academy of Sciences, Institute of Biological Physics, Pushchino, USSR); Akoev, I.G. (Ministerstvo Zdravookhraneniia SSSR, Institut Mediko-Biologicheskikh Problem, Moscow, USSR)

    1979-01-01

    During the experiment Spore-ring Forming Fungi Biorhythm of the Apollo-Soyuz test project the Rhythm-1 apparatus contained a dried film culture of bacteriophage T4Br(+), growing cultures of Actinomyces and plastic nuclear particle detectors. The following were studied: the frequency of induction of r mutations in the bacteriophage film per 20,000 surviving particles, the spectrum of mutant types obtained (rI, rII, rIII), and the possible molecular mechanisms for the occurrence of rII mutants with due regard to the registered tracks of heavy nuclear particles. The studies showed that the local radiation due to heavy nuclear particle tracks plays a major role in space radiation damage.

  12. Studies on the Origin of Plant Bacteriophages in an Artifcial Inoculation Condition%人T接种条件下植物病原细菌噬菌体来源的研究

    Institute of Scientific and Technical Information of China (English)

    涂立超; 成国英; 于大胜; 杨国桂

    2001-01-01

    对盆栽水稻采用针刺、喷雾、盆水等不同方法接种水稻细菌性条斑病病菌后,检测稻株发病和盆水中的噬菌体,结果表明:未接种稻细条病菌的处理中,无稻株发病,盆水中也未测到噬菌体;3种接种处理均可引致稻株发病,并先后在其盆水中检测到噬菌体,说明噬菌体与致病菌有密切的伴随关系。在采用叶面喷雾和盆水接种稻白叶枯自然组合菌株B-1和单细胞系菌株Ⅳ-16试验中,B-1处理后能引起稻株发病,且在盆水中测到噬菌体;而Ⅳ-16处理后虽引起稻株发病,但盆水中无噬菌体,结果表明:在人工接种条件下植物病原细菌噬菌体是由病菌中的溶原细胞传带而来的。%5 days after the leaves of rice plants in polythere bacins were inoculating with the suspention of Xanthomonas oryzae pv. oryzicola strain by needle-pricking, spraying and pouring it in rice basins' water, the percentages of diseased plants and the quantities of phages in the rice basins' water were checked up periodically. The results showed that three kinds of inoculation methods all succeeded in causing bacterial leaf streak (BLS), the bacteriophages were detected in the rice basins' water, while there were no diseased plants and phages in non-inoculated rice basins, which indicted there was a close companionate relationship between the pathogen and the phage. When the rice plants and the rice basins' water were inoculated with the natural composite strain of B-1 and the monocell colony strain of IV-16 of X. oryzae pv. oryzae, both the bacterial leaf blight (BLB) and phages were detected in the treatment with B-l, but altnough the BLB appeared on the rice plants and no phage was detected in the treatment with Ⅳ16,which suggested that the bacteriophages were be transmitted by the lysogenic cell (cells affected by temperate phages) among the composite strain cells in the artificial inoculation condition.

  13. 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

  14. 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...

  15. 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.

  16. 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

  17. 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.

  18. 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

  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

    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; 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.

  1. 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

  2. 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.

  3. 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

  4. The use of genomic signature distance between bacteriophages and their hosts displays evolutionary relationships and phage growth cycle determination.

    OpenAIRE

    Regeard Christophe; DuBow Michael S; Deschavanne Patrick

    2010-01-01

    Abstract Background Bacteriophage classification is mainly based on morphological traits and genome characteristics combined with host information and in some cases on phage growth lifestyle. A lack of molecular tools can impede more precise studies on phylogenetic relationships or even a taxonomic classification. The use of methods to analyze genome sequences without the requirement for homology has allowed advances in classification. Results Here, we proposed to use genome sequence signatur...

  5. Back to the future: evolving bacteriophages to increase their effectiveness against the pathogen Pseudomonas aeruginosa PAO1

    OpenAIRE

    Betts, Alex; Vasse, Marie; Kaltz, Oliver; Hochberg, Michael E.

    2013-01-01

    Antibiotic resistance is becoming increasingly problematic for the treatment of infectious disease in both humans and livestock. The bacterium Pseudomonas aeruginosa is often found to be resistant to multiple antibiotics and causes high patient mortality in hospitals. Bacteriophages represent a potential option to combat pathogenic bacteria through their application in phage therapy. Here, we capitalize on previous studies showing how evolution may increase phage infection capacity relative t...

  6. Lysogeny with Shiga toxin 2-encoding bacteriophages represses type III secretion in enterohemorrhagic Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Xuefang Xu

    Full Text Available Lytic or lysogenic infections by bacteriophages drive the evolution of enteric bacteria. Enterohemorrhagic Escherichia coli (EHEC have recently emerged as a significant zoonotic infection of humans with the main serotypes carried by ruminants. Typical EHEC strains are defined by the expression of a type III secretion (T3S system, the production of Shiga toxins (Stx and association with specific clinical symptoms. The genes for Stx are present on lambdoid bacteriophages integrated into the E. coli genome. Phage type (PT 21/28 is the most prevalent strain type linked with human EHEC infections in the United Kingdom and is more likely to be associated with cattle shedding high levels of the organism than PT32 strains. In this study we have demonstrated that the majority (90% of PT 21/28 strains contain both Stx2 and Stx2c phages, irrespective of source. This is in contrast to PT 32 strains for which only a minority of strains contain both Stx2 and 2c phages (28%. PT21/28 strains had a lower median level of T3S compared to PT32 strains and so the relationship between Stx phage lysogeny and T3S was investigated. Deletion of Stx2 phages from EHEC strains increased the level of T3S whereas lysogeny decreased T3S. This regulation was confirmed in an E. coli K12 background transduced with a marked Stx2 phage followed by measurement of a T3S reporter controlled by induced levels of the LEE-encoded regulator (Ler. The presence of an integrated Stx2 phage was shown to repress Ler induction of LEE1 and this regulation involved the CII phage regulator. This repression could be relieved by ectopic expression of a cognate CI regulator. A model is proposed in which Stx2-encoding bacteriophages regulate T3S to co-ordinate epithelial cell colonisation that is promoted by Stx and secreted effector proteins.

  7. Lysogeny with Shiga toxin 2-encoding bacteriophages represses type III secretion in enterohemorrhagic Escherichia coli.

    Science.gov (United States)

    Xu, Xuefang; McAteer, Sean P; Tree, Jai J; Shaw, Darren J; Wolfson, Eliza B K; Beatson, Scott A; Roe, Andrew J; Allison, Lesley J; Chase-Topping, Margo E; Mahajan, Arvind; Tozzoli, Rosangela; Woolhouse, Mark E J; Morabito, Stefano; Gally, David L

    2012-01-01

    Lytic or lysogenic infections by bacteriophages drive the evolution of enteric bacteria. Enterohemorrhagic Escherichia coli (EHEC) have recently emerged as a significant zoonotic infection of humans with the main serotypes carried by ruminants. Typical EHEC strains are defined by the expression of a type III secretion (T3S) system, the production of Shiga toxins (Stx) and association with specific clinical symptoms. The genes for Stx are present on lambdoid bacteriophages integrated into the E. coli genome. Phage type (PT) 21/28 is the most prevalent strain type linked with human EHEC infections in the United Kingdom and is more likely to be associated with cattle shedding high levels of the organism than PT32 strains. In this study we have demonstrated that the majority (90%) of PT 21/28 strains contain both Stx2 and Stx2c phages, irrespective of source. This is in contrast to PT 32 strains for which only a minority of strains contain both Stx2 and 2c phages (28%). PT21/28 strains had a lower median level of T3S compared to PT32 strains and so the relationship between Stx phage lysogeny and T3S was investigated. Deletion of Stx2 phages from EHEC strains increased the level of T3S whereas lysogeny decreased T3S. This regulation was confirmed in an E. coli K12 background transduced with a marked Stx2 phage followed by measurement of a T3S reporter controlled by induced levels of the LEE-encoded regulator (Ler). The presence of an integrated Stx2 phage was shown to repress Ler induction of LEE1 and this regulation involved the CII phage regulator. This repression could be relieved by ectopic expression of a cognate CI regulator. A model is proposed in which Stx2-encoding bacteriophages regulate T3S to co-ordinate epithelial cell colonisation that is promoted by Stx and secreted effector proteins.

  8. Biochemical characterization of a thermostable HNH endonuclease from deep-sea thermophilic bacteriophage GVE2.

    Science.gov (United States)

    Zhang, Likui; Huang, Yanchao; Xu, Dandan; Yang, Lixiang; Qian, Kaicheng; Chang, Guozhu; Gong, Yong; Zhou, Xiaojian; Ma, Kesen

    2016-09-01

    His-Asn-His (HNH) proteins are a very common family of small nucleic acid-binding proteins that are generally associated with endonuclease activity and are found in all kingdoms of life. Although HNH endonucleases from mesophiles have been widely investigated, the biochemical functions of HNH endonucleases from thermophilic bacteriophages remain unknown. Here, we characterized the biochemical properties of a thermostable HNH endonuclease from deep-sea thermophilic bacteriophage GVE2. The recombinant GVE2 HNH endonuclease exhibited non-specific cleavage activity at high temperature. The optimal temperature of the GVE2 HNH endonuclease for cleaving DNA was 60-65 °C, and the enzyme retained its DNA cleavage activity even after heating at 100 °C for 30 min, suggesting the enzyme is a thermostable endonuclease. The GVE2 HNH endonuclease cleaved DNA over a wide pH spectrum, ranging from 5.5 to 9.0, and the optimal pH for the enzyme activity was 8.0-9.0. Furthermore, the GVE2 HNH endonuclease activity was dependent on a divalent metal ion. While the enzyme is inactive in the presence of Cu(2+), the GVE2 HNH endonuclease displayed cleavage activity of varied efficiency with Mn(2+), Mg(2+), Ca(2+), Fe(2+), Co(2+), Zn(2+), and Ni(2+). The GVE2 HNH endonuclease activity was inhibited by NaCl. This study provides the basis for determining the role of this endonuclease in life cycle of the bacteriophage GVE2 and suggests the potential application of the enzyme in molecular biology and biotechnology. PMID:27131500

  9. [Experience of using bacteriophages and bitsillin-5 to reduce the incidence of respiratory diseases of bacterial ethiology in military personnel].

    Science.gov (United States)

    Akimkin, V G; Kalmykov, A A; Aminev, R M; Polyakov, V S; Artebyakin, S V

    2016-02-01

    The authors defined epidemiological efficacy and safety of the use of bacteriophages(streptococcal, staphylococcal, piobakferiophage multipartial) and bitsillin-5 to reduce tonsillitis morbidityand other respiratory diseases with bacterial etiology in groups of servicemen during their formationagainst increase of seasonal morbidity. The results of the use of these preventive agents were evaluatedby a comparative analysis of this disease in experimental and control groups. In total 510 healthy conscriptswere involved into the study. The effectiveness of prophylactic use of bacteriophages and bitsillin-5, whichprovided a reduction in the incidence of respiratory infections of bacterial ethiology, tonsillitis, and otherrespiratory diseases is showed. Recommendations on the choice of drugsfor the prevention of these infections,methods and organization of their application in organized groups are given.

  10. The Role of MOR and the CI Operator Sites on the Genetic Switch of the Temperate Bacteriophage TP901-1

    DEFF Research Database (Denmark)

    Pedersen, Margit; Hammer, Karin

    2008-01-01

    A genetic switch controls whether the temperate bacteriophage TP901-1 will enter a lytic or a lysogenic life cycle after infection of its host, Lactococcus lactis. We studied this bistable switch encoded in a small DNA fragment of 979 bp by fusing it to a reporter gene on a low-copy-number plasmid...

  11. A metagenomic approach to characterize temperate bacteriophage populations from Cystic Fibrosis and non-Cystic Fibrosis bronchiectasis patients.

    Science.gov (United States)

    Tariq, Mohammad A; Everest, Francesca L C; Cowley, Lauren A; De Soyza, Anthony; Holt, Giles S; Bridge, Simon H; Perry, Audrey; Perry, John D; Bourke, Stephen J; Cummings, Stephen P; Lanyon, Clare V; Barr, Jeremy J; Smith, Darren L

    2015-01-01

    Pseudomonas aeruginosa (Pa), normally a soil commensal, is an important opportunistic pathogen in Cystic Fibrosis (CF) and non-Cystic Fibrosis Bronchiectasis (nCFBR). Persistent infection correlates with accelerated decline in lung function and early mortality. The horizontal transfer of DNA by temperate bacteriophages can add gene function and selective advantages to their bacterial host within the constrained environment of the lower lung. In this study, we chemically induce temperate bacteriophages from clonal cultures of Pa and identify their mixed viral communities employing metagenomic approaches. We compared 92 temperate phage metagenomes stratified from these clinical backgrounds (47 CF and 45 nCFBR Pa isolates) using MG-RAST and GeneWise2. KEGG analysis shows the complexity of temperate phage accessory gene carriage increases with duration and severity of the disease. Furthermore, we identify the presence of Ig-like motifs within phage structural genes linked to bacterial adhesion and carbohydrate binding including Big_2, He_Pig, and Fn3. This study provides the first clinical support to the proposed bacteriophage adherence to mucus (BAM) model and the evolution of phages interacting at these mucosal surfaces over time. PMID:25741327

  12. A Metagenomic approach to characterize temperate bacteriophage populations from cystic fibrosis and non-cystic fibrosis bronchiectasis patients

    Directory of Open Access Journals (Sweden)

    Mohammad Adnan Tariq

    2015-02-01

    Full Text Available Pseudomonas aeruginosa (Pa, normally a soil commensal, is an important opportunistic pathogen in Cystic Fibrosis (CF and non-Cystic Fibrosis Bronchiectasis (nCFBR. Persistent infection correlates with accelerated decline in lung function and early mortality. The horizontal transfer of DNA by temperate bacteriophages can add gene function and selective advantages to their bacterial host within the constrained environment of the lower lung. In this study, we chemically induce temperate bacteriophages from clonal cultures of Pa and identify their mixed viral communities employing metagenomic approaches. We compared 92 temperate phage metagenomes stratified from these clinical backgrounds (47 CF and 45 nCFBR Pa isolates using MG-RAST and GeneWise2. KEGG analysis shows the complexity of temperate phage accessory gene carriage increases with duration and severity of the disease. Furthermore we identify the presence of Ig-like motifs within phage structural genes linked to bacterial adhesion and carbohydrate binding including Big_2, He_Pig and Fn3. This study provides the first clinical support to the proposed bacteriophage adherence to mucus (BAM model and the evolution of phages interacting at these mucosal surfaces over time.

  13. 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.

  14. Isolation and characterisation of lytic bacteriophages of Klebsiella pneumoniae and Klebsiella oxytoca.

    Science.gov (United States)

    Karumidze, Natia; Kusradze, Ia; Rigvava, Sophio; Goderdzishvili, Marine; Rajakumar, Kumar; Alavidze, Zemphira

    2013-03-01

    Klebsiella bacteria have emerged as an increasingly important cause of community-acquired nosocomial infections. Extensive use of broad-spectrum antibiotics in hospitalised patients has led to both increased carriage of Klebsiella and the development of multidrug-resistant strains that frequently produce extended-spectrum β-lactamases and/or other defences against antibiotics. Many of these strains are highly virulent and exhibit a strong propensity to spread. In this study, six lytic Klebsiella bacteriophages were isolated from sewage-contaminated river water in Georgia and characterised as phage therapy candidates. Two of the phages were investigated in greater detail. Biological properties, including phage morphology, nucleic acid composition, host range, growth phenotype, and thermal and pH stability were studied for all six phages. Limited sample sequencing was performed to define the phylogeny of the K. pneumoniae- and K. oxytoca-specific bacteriophages vB_Klp_5 and vB_Klox_2, respectively. Both of the latter phages had large burst sizes, efficient rates of adsorption and were stable under different adverse conditions. Phages reported in this study are double-stranded DNA bacterial viruses belonging to the families Podoviridae and Siphoviridae. One or more of the six phages was capable of efficiently lysing ~63 % of Klebsiella strains comprising a collection of 123 clinical isolates from Georgia and the United Kingdom. These phages exhibit a number of properties indicative of potential utility in phage therapy cocktails.

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. Isolation and characterization of Enterobacteriaceae species infesting post-harvest strawberries and their biological control using bacteriophages.

    Science.gov (United States)

    Kurtböke, D Ipek; Palk, A; Marker, A; Neuman, C; Moss, L; Streeter, K; Katouli, M

    2016-10-01

    Strawberry is a significantly consumed fruit worldwide, mostly without being subjected to disinfection processes. During the harvest and transfer from farm to consumers as well as where organic farming practises have been employed, the surface of the fruit may become contaminated by pathogenic bacteria. Post-harvest strawberry fruits in punnets available for public consumption were thus screened for the presence of enteric bacteria in the Sunshine Coast region of Queensland, Australia. Some of the tested samples (13 %) were found to carry such bacteria and even in greater numbers if organic amendments were used (69 %). The bacteria were found to belong in the genera of Escherichia, Enterobacter, Raoultella, Klebsiella, Pantoea, Shigella, Citrobacter and Cronobacter within the family Enterobacteriaceae. Some of the isolates were found to adhere to Caco-2 cells representing human gut epithelium as well as carrying virulence and toxin genes. Resistance mostly against sulphafurazole, cefoxitin, ampicillin and nitrofurantoin was found among 14 different antimicrobial agents tested including 100 % resistance to cefoxitin and ampicillin in the genus Pantoea. In the second phase of the study, bacteriophages were isolated against the isolates and were subsequently applied to post-harvest fruits. A significant (P ≤ 0.001) reduction in the number of enteric bacteria was observed when a high-titre polyvalent bacteriophage suspension (×10(12) PFU/mL) was applied to the fruit surface. Bacteriophages also decreased the adhesion of the Escherichia coli isolates to Caco-2 cells. Findings might indicate that biological control using bacteriophages might be of significant value for the industry targeting to reduce pathogenic loads of bacteria on the fruit.

  3. Bacteriophages of Staphylococcus aureus efficiently package various bacterial genes and mobile genetic elements including SCCmec with different frequencies.

    Science.gov (United States)

    Mašlaňová, Ivana; Doškař, Jiří; Varga, Marian; Kuntová, Lucie; Mužík, Jan; Malúšková, Denisa; Růžičková, Vladislava; Pantůček, Roman

    2013-02-01

    Staphylococcus aureus is a serious human and veterinary pathogen in which new strains with increasing virulence and antimicrobial resistance occur due to acquiring new genes by horizontal transfer. It is generally accepted that temperate bacteriophages play a major role in gene transfer. In this study, we proved the presence of various bacterial genes of the S. aureus COL strain directly within the phage particles via qPCR and quantified their packaging frequency. Non-parametric statistical analysis showed that transducing bacteriophages φ11, φ80 and φ80α of serogroup B, in contrast to serogroup A bacteriophage φ81, efficiently package selected chromosomal genes localized in 4 various loci of the chromosome and 8 genes carried on variable elements, such as staphylococcal cassette chromosome SCCmec, staphylococcal pathogenicity island SaPI1, genomic islands vSaα and vSaβ, and plasmids with various frequency. Bacterial gene copy number per ng of DNA isolated from phage particles ranged between 1.05 × 10(2) for the tetK plasmid gene and 3.86 × 10(5) for the SaPI1 integrase gene. The new and crucial finding that serogroup B bacteriophages can package concurrently ccrA1 (1.16 × 10(4)) and mecA (1.26 × 10(4)) located at SCCmec type I into their capsids indicates that generalized transduction plays an important role in the evolution and emergence of new methicillin-resistant clones.

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

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    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.

  5. Comparative genomic analysis of bacteriophages specific to the channel catfish pathogen Edwardsiella ictaluri

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    Mead David A

    2011-01-01

    Full Text Available Abstract Background The bacterial pathogen Edwardsiella ictaluri is a primary cause of mortality in channel catfish raised commercially in aquaculture farms. Additional treatment and diagnostic regimes are needed for this enteric pathogen, motivating the discovery and characterization of bacteriophages specific to E. ictaluri. Results The genomes of three Edwardsiella ictaluri-specific bacteriophages isolated from geographically distant aquaculture ponds, at different times, were sequenced and analyzed. The genomes for phages eiAU, eiDWF, and eiMSLS are 42.80 kbp, 42.12 kbp, and 42.69 kbp, respectively, and are greater than 95% identical to each other at the nucleotide level. Nucleotide differences were mostly observed in non-coding regions and in structural proteins, with significant variability in the sequences of putative tail fiber proteins. The genome organization of these phages exhibit a pattern shared by other Siphoviridae. Conclusions These E. ictaluri-specific phage genomes reveal considerable conservation of genomic architecture and sequence identity, even with considerable temporal and spatial divergence in their isolation. Their genomic homogeneity is similarly observed among E. ictaluri bacterial isolates. The genomic analysis of these phages supports the conclusion that these are virulent phages, lacking the capacity for lysogeny or expression of virulence genes. This study contributes to our knowledge of phage genomic diversity and facilitates studies on the diagnostic and therapeutic applications of these phages.

  6. Recent advances in bacteriophage based biosensors for food-borne pathogen detection.

    Science.gov (United States)

    Singh, Amit; Poshtiban, Somayyeh; Evoy, Stephane

    2013-01-30

    Foodborne diseases are a major health concern that can have severe impact on society and can add tremendous financial burden to our health care systems. Rapid early detection of food contamination is therefore relevant for the containment of food-borne pathogens. Conventional pathogen detection methods, such as microbiological and biochemical identification are time-consuming and laborious, while immunological or nucleic acid-based techniques require extensive sample preparation and are not amenable to miniaturization for on-site detection. Biosensors have shown tremendous promise to overcome these limitations and are being aggressively studied to provide rapid, reliable and sensitive detection platforms for such applications. Novel biological recognition elements are studied to improve the selectivity and facilitate integration on the transduction platform for sensitive detection. Bacteriophages are one such unique biological entity that show excellent host selectivity and have been actively used as recognition probes for pathogen detection. This review summarizes the extensive literature search on the application of bacteriophages (and recently their receptor binding proteins) as probes for sensitive and selective detection of foodborne pathogens, and critically outlines their advantages and disadvantages over other recognition elements.

  7. Recent Advances in Bacteriophage Based Biosensors for Food-Borne Pathogen Detection

    Directory of Open Access Journals (Sweden)

    Somayyeh Poshtiban

    2013-01-01

    Full Text Available Foodborne diseases are a major health concern that can have severe impact on society and can add tremendous financial burden to our health care systems. Rapid early detection of food contamination is therefore relevant for the containment of food-borne pathogens. Conventional pathogen detection methods, such as microbiological and biochemical identification are time-consuming and laborious, while immunological or nucleic acid-based techniques require extensive sample preparation and are not amenable to miniaturization for on-site detection. Biosensors have shown tremendous promise to overcome these limitations and are being aggressively studied to provide rapid, reliable and sensitive detection platforms for such applications. Novel biological recognition elements are studied to improve the selectivity and facilitate integration on the transduction platform for sensitive detection. Bacteriophages are one such unique biological entity that show excellent host selectivity and have been actively used as recognition probes for pathogen detection. This review summarizes the extensive literature search on the application of bacteriophages (and recently their receptor binding proteins as probes for sensitive and selective detection of foodborne pathogens, and critically outlines their advantages and disadvantages over other recognition elements.

  8. Characterization of a novel non-specific nuclease from thermophilic bacteriophage GBSV1

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    Zhang Xiaobo

    2008-04-01

    Full Text Available Abstract Background Thermostable enzymes from thermophiles have attracted extensive studies. In this investigation, a nuclease-encoding gene (designated as GBSV1-NSN was obtained from a thermophilic bacteriophage GBSV1 for the first time. Results After recombinant expression in Escherichia coli, the purified GBSV1-NSN exhibited non-specific nuclease activity, being able to degrade various nucleic acids, including RNA, single-stranded DNA and double-stranded DNA that was circular or linear. Based on sequence analysis, the nuclease shared no homology with any known nucleases, suggesting that it was a novel nuclease. The characterization of the recombinant GBSV1-NSN showed that its optimal temperature and pH were 60°C and 7.5, respectively. The results indicated that the enzymatic activity was inhibited by enzyme inhibitors or detergents, such as ethylene diamine tetraacetic acid, citrate, dithiothreitol, β-mercaptoethanol, guanidine hydrochloride, urea and SDS. In contrast, the nuclease activity was enhanced by TritonX-100, Tween-20 or chaps to approximately 124.5% – 141.6%. The Km of GBSV1-NSN nuclease was 231, 61 and 92 μM, while its kcat was 1278, 241 and 300 s-1 for the cleavage of dsDNA, ssDNA and RNA, respectively. Conclusion Our study, therefore, presented a novel thermostable non-specific nuclease from thermophilic bacteriophage and its overexpression and purification for scientific research and applications.

  9. Identification of bacteriophage virion proteins by the ANOVA feature selection and analysis.

    Science.gov (United States)

    Ding, Hui; Feng, Peng-Mian; Chen, Wei; Lin, Hao

    2014-08-01

    The bacteriophage virion proteins play extremely important roles in the fate of host bacterial cells. Accurate identification of bacteriophage virion proteins is very important for understanding their functions and clarifying the lysis mechanism of bacterial cells. In this study, a new sequence-based method was developed to identify phage virion proteins. In the new method, the protein sequences were initially formulated by the g-gap dipeptide compositions. Subsequently, the analysis of variance (ANOVA) with incremental feature selection (IFS) was used to search for the optimal feature set. It was observed that, in jackknife cross-validation, the optimal feature set including 160 optimized features can produce the maximum accuracy of 85.02%. By performing feature analysis, we found that the correlation between two amino acids with one gap was more important than other correlations for phage virion protein prediction and that some of the 1-gap dipeptides were important and mainly contributed to the virion protein prediction. This analysis will provide novel insights into the function of phage virion proteins. On the basis of the proposed method, an online web-server, PVPred, was established and can be freely accessed from the website (http://lin.uestc.edu.cn/server/PVPred). We believe that the PVPred will become a powerful tool to study phage virion proteins and to guide the related experimental validations.

  10. Induction and characterization of a lysogenic bacteriophage of Lactococcus garvieae isolated from marine fish species.

    Science.gov (United States)

    Hoai, T D; Yoshida, T

    2016-07-01

    This study investigated the presence of prophages in Lactococcus garvieae isolated from several marine fish species in Japan. Representative strains of 16 bacterial genotypes (S1-S16) selected from more than 400 L. garvieae isolates were used to induce lysogenic bacteriophages. These strains were treated with 500 ng mL(-1) freshly prepared mitomycin C. A cross-spotting assay was performed to validate the lysogenic and indicator strains. The lysogenic strains were selected for isolation and concentration of the phages. Phage DNA was digested with EcoRI for biased sinusoidal field gel electrophoresis analysis. Polymerase chain reaction (PCR) was used to detect integrated prophage DNA. Of the 16 representative bacterial genotypes, 12 strains integrated prophages as indicated by the PCR assay, and 10 phages were detected and isolated using two indicator bacterial strains. Analysis of genomic DNA showed that these phages were homologous and named as PLgT-1. Transmission electron microscopy revealed that the morphology of PLgT-1 was consistent with the virus family Siphoviridae. PCR analysis of the prophage DNA revealed that all of the S1 genotype strains were lysogenic (30/30), but none of the S16 genotype strains were lysogenic (0/30). This is the first study to investigate lysogenic bacteriophages from L. garvieae. PMID:26471724

  11. Evidence of host-virus co-evolution in tetranucleotide usage patterns of bacteriophages and eukaryotic viruses

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    Ghose Chandrabali

    2006-01-01

    Full Text Available Abstract Background Virus taxonomy is based on morphologic characteristics, as there are no widely used non-phenotypic measures for comparison among virus families. We examined whether there is phylogenetic signal in virus nucleotide usage patterns that can be used to determine ancestral relationships. The well-studied model of tail morphology in bacteriophage classification was used for comparison with nucleotide usage patterns. Tetranucleotide usage deviation (TUD patterns were chosen since they have previously been shown to contain phylogenetic signal similar to that of 16S rRNA. Results We found that bacteriophages have unique TUD patterns, representing genomic signatures that are relatively conserved among those with similar host range. Analysis of TUD-based phylogeny indicates that host influences are important in bacteriophage evolution, and phylogenies containing both phages and their hosts support their co-evolution. TUD-based phylogeny of eukaryotic viruses indicates that they cluster largely based on nucleic acid type and genome size. Similarities between eukaryotic virus phylogenies based on TUD and gene content substantiate the TUD methodology. Conclusion Differences between phenotypic and TUD analysis may provide clues to virus ancestry not previously inferred. As such, TUD analysis provides a complementary approach to morphology-based systems in analysis of virus evolution.

  12. Biogeography of bacteriophages at four hydrothermal vent sites in the Antarctic based on g23 sequence diversity.

    Science.gov (United States)

    Millard, Andrew D; Pearce, David; Zwirglmaier, Katrin

    2016-04-01

    In this study, which was carried out within the ChEsSO consortium project (Chemosynthetically driven ecosystems south of the Polar Front), we sampled two hydrothermal vent sites on the East Scotia Ridge, Scotia Sea, one in the Kemp Caldera, South Sandwich Arc and one in the Bransfield Strait, north-west of the Antarctic Peninsula, which exhibit strong differences in their chemical characteristics. We compared a subset of their bacteriophage population by Sanger- and 454-sequencing of g23, which codes for the major capsid protein of T4likeviruses. We found that the sites differ vastly in their bacteriophage diversity, which reflects the differences in the chemical conditions and therefore putatively the differences in microbial hosts living at these sites. Comparing phage diversity in the vent samples to other aquatic samples, the vent samples formed a distinct separate cluster, which also included the non-vent control samples that were taken several hundred meters above the vent chimneys. This indicates that the influence of the vents on the microbial population and therefore also the bacteriophage population extends much further than anticipated.

  13. Development of a novel bacteriophage based biomagnetic separation method as an aid for sensitive detection of viable Escherichia coli.

    Science.gov (United States)

    Wang, Ziyuan; Wang, Danhui; Chen, Juhong; Sela, David A; Nugen, Sam R

    2016-02-01

    The application of bacteriophage combined with the use of magnetic separation techniques has emerged as a valuable tool for the sensitive identification and detection of bacteria. In this study, bacteriophage T7 labelled magnetic beads were developed for the detection of viable bacterial cells. Fusion of the biotin acceptor peptide (BAP) with the phage capsid protein gene and the insertion of the biotin ligase (BirA) gene enabled the display of the BAP ligand and the expression protein BirA during the replication cycle of phage infection. The replicated Escherichia coli specific bacteriophage was biotinylated in vivo and coated on magnetic beads via streptavidin-biotin interaction. Immobilization efficiency of the recombinant phage was investigated on magnetic beads and the phage-bead complex was evaluated by detecting E. coli from inoculated broth. When compared to the wild type phage, the recombinant phage T7birA-bap had a high immobilization density on streptavidin-coated magnetic beads and could capture 86.2% of E. coli cells from broth within 20 min. As this phage-based biomagnetic detection approach provided a low detection limit of 10(2) CFU mL(-1) without pre-enrichment, we believe this assay could be further developed to detect other bacteria of interest by applying host-specific phages. This would be of particular use in detecting bacteria which are difficult to grow or replicate slowly in culture.

  14. Application of the VPp1 bacteriophage combined with a coupled enzyme system in the rapid detection of Vibrio parahaemolyticus.

    Science.gov (United States)

    Peng, Yong; Jin, Yanqiu; Lin, Hong; Wang, Jingxue; Khan, Muhammad Naseem

    2014-03-01

    For rapid and quantitative detection of Vibrio parahaemolyticus, a method combining the specific lysis of bacteriophages with a bacterial luciferase-flavin mononucleotide:nicotinamide adenine dinucleotide oxidoreductase bioluminescent system in vitro was developed. A V. parahaemolyticus detection system was established by optimizing three main influencing factors: bacteriophage titer, volume ratio of the bacteriophage to its host bacterium, and lysis time. A standard curve between the number of bacteria and the luminescence intensity of the coupled enzyme system was studied and revealed a good linear relationship. More than 10(7)colony-forming units (cfu)·ml(-1) bacteria in pure culture and >10(8) cfu·ml(-1) bacteria in oyster samples were readily detected without pre-enrichment. Furthermore, >10(0) cfu·ml(-1) bacteria in oyster samples were readily detected after 4h of enrichment culture. Because of its rapid detection, high specificity, and simplicity in operation, this method is an effective tool for detecting living bacteria in food and environmental samples.

  15. Biogeography of bacteriophages at four hydrothermal vent sites in the Antarctic based on g23 sequence diversity.

    Science.gov (United States)

    Millard, Andrew D; Pearce, David; Zwirglmaier, Katrin

    2016-04-01

    In this study, which was carried out within the ChEsSO consortium project (Chemosynthetically driven ecosystems south of the Polar Front), we sampled two hydrothermal vent sites on the East Scotia Ridge, Scotia Sea, one in the Kemp Caldera, South Sandwich Arc and one in the Bransfield Strait, north-west of the Antarctic Peninsula, which exhibit strong differences in their chemical characteristics. We compared a subset of their bacteriophage population by Sanger- and 454-sequencing of g23, which codes for the major capsid protein of T4likeviruses. We found that the sites differ vastly in their bacteriophage diversity, which reflects the differences in the chemical conditions and therefore putatively the differences in microbial hosts living at these sites. Comparing phage diversity in the vent samples to other aquatic samples, the vent samples formed a distinct separate cluster, which also included the non-vent control samples that were taken several hundred meters above the vent chimneys. This indicates that the influence of the vents on the microbial population and therefore also the bacteriophage population extends much further than anticipated. PMID:26903011

  16. Lytic infection of Lactococcus lactis by bacteriophages Tuc2009 and c2 triggers alternative transcriptional host responses.

    Science.gov (United States)

    Ainsworth, Stuart; Zomer, Aldert; Mahony, Jennifer; van Sinderen, Douwe

    2013-08-01

    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 throughout lytic infection. Whole-genome microarrays performed at various time points postinfection demonstrated a rather modest impact on host transcription. The majority of changes in the host transcriptome occur during late infection stages; few changes in host gene transcription occur during the immediate and early infection stages. Alterations in the L. lactis UC509.9 transcriptome during lytic infection appear to be phage specific, with relatively few differentially transcribed genes shared between cells infected with Tuc2009 and those infected with c2. Despite the apparent lack of a coordinated general phage response, three themes common to both infections were noted: alternative transcription of genes involved in catabolic flux and energy production, differential transcription of genes involved in cell wall modification, and differential transcription of genes involved in the conversion of ribonucleotides to deoxyribonucleotides. The transcriptional profiles of both bacteriophages during lytic infection generally correlated with the findings of previous studies and allowed the confirmation of previously predicted promoter sequences. In addition, the host transcriptional response to lysogenization with Tuc2009 was monitored along with tiling array analysis of Tuc2009 in the lysogenic state. Analysis identified 44 host genes with altered transcription during lysogeny, 36 of which displayed levels of transcription significantly reduced from those for uninfected cells.

  17. 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.

  18. Phospholipid vesicles encapsulated bacteriophage: A novel approach to enhance phage biodistribution.

    Science.gov (United States)

    Singla, S; Harjai, K; Raza, K; Wadhwa, S; Katare, O P; Chhibber, S

    2016-10-01

    Phage therapy has been at the centre of attraction for combating multi-drug resistant strains. However, less stability and rapid clearance of phage by mononuclear phagocytic system (MPS) restricts its use in humans. In the present study, aim was to develop a liposomal delivery system for bacteriophage that can assure efficient phage delivery and retention at the site of infection. Different ratios of cholesterol, lipids and surfactant along with different charge inducers were employed to prepare liposomes. Phage was then entrapped in the liposomes and characterized on the basis of morphology, size, entrapment efficiency and stability. Further, in vivo biodistribution of free phage and liposome entrapped phage was compared in different organs of mice. A cationic liposomal formulation showed maximum encapsulation efficiency of 92%. Transmission electron microscopy (TEM) confirmed the entrapment of phages in liposomes. Liposome preparation was found to be most stable at 4°C during storage. Liposome entrapped bacteriophage was retained for longer duration in different organs i.e. upto day 4 in blood, day 6 in liver, lungs and kidney, 14days in spleen of mice as compared to free phage that became undetectable by 36th h in blood as well as lungs and by 48th h in all other organs. PMID:27393682

  19. On-demand isolation of bacteriophages against drug-resistant bacteria for personalized phage therapy

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    Sari eMattila

    2015-11-01

    Full Text Available Bacteriophages are bacterial viruses, capable of killing even multi-drug resistant bacterial cells. For this reason, therapeutic use of phages is considered as a possible alternative to conventional antibiotics. However, phages are very host specific in comparison to wide-spectrum antibiotics and thus preparation of phage-cocktails beforehand against pathogens can be difficult. In this study, we evaluate whether it may be possible to isolate phages on-demand from environmental reservoir. We attempted to enrich infectious bacteriophages from sewage against nosocomial drug-resistant bacterial strains of different medically important species in order to evaluate the probability of discovering novel therapeutic phages. Stability and host-range were determined for the acquired phages. Our results suggest that on-demand isolation of phages is possible against Pseudomonas aeruginosa, Salmonella and extended spectrum beta-lactamase (ESBL Escherichia coli and Klebsiella pneumoniae. The probability of finding suitable phages was less than 40% against vancomycin resistant Enterococcus (VRE and Acinetobacter baumannii strains. Furthermore, isolation of new phages against methicillin resistant Staphylococcus aureus (MRSA strains was found to be very difficult.

  20. Metagenomic analysis reveals that bacteriophages are reservoirs of antibiotic resistance genes.

    Science.gov (United States)

    Subirats, Jéssica; Sànchez-Melsió, Alexandre; Borrego, Carles M; Balcázar, José Luis; Simonet, Pascal

    2016-08-01

    A metagenomics approach was applied to explore the presence of antibiotic resistance genes (ARGs) in bacteriophages from hospital wastewater. Metagenomic analysis showed that most phage sequences affiliated to the order Caudovirales, comprising the tailed phage families Podoviridae, Siphoviridae and Myoviridae. Moreover, the relative abundance of ARGs in the phage DNA fraction (0.26%) was higher than in the bacterial DNA fraction (0.18%). These differences were particularly evident for genes encoding ATP-binding cassette (ABC) and resistance-nodulation-cell division (RND) proteins, phosphotransferases, β-lactamases and plasmid-mediated quinolone resistance. Analysis of assembled contigs also revealed that blaOXA-10, blaOXA-58 and blaOXA-24 genes belonging to class D β-lactamases as well as a novel blaTEM (98.9% sequence similarity to the blaTEM-1 gene) belonging to class A β-lactamases were detected in a higher proportion in phage DNA. Although preliminary, these findings corroborate the role of bacteriophages as reservoirs of resistance genes and thus highlight the necessity to include them in future studies on the emergence and spread of antibiotic resistance in the environment.

  1. Inhibition of Biofilm Formation by T7 Bacteriophages Producing Quorum-Quenching Enzymes

    Science.gov (United States)

    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 polysaccharides and may have limited effects on natural multispecies biofilms. In this study, an engineered T7 bacteriophage was constructed to encode a lactonase enzyme with broad-range activity for quenching of quorum sensing, a form of bacterial cell-cell communication via small chemical molecules (acyl homoserine lactones [AHLs]) that is necessary for biofilm formation. Our results demonstrated that the engineered T7 phage expressed the AiiA lactonase to effectively degrade AHLs from many bacteria. Addition of the engineered T7 phage to mixed-species biofilms containing Pseudomonas aeruginosa and Escherichia coli resulted in inhibition of biofilm formation. Such quorum-quenching phages that can lyse host bacteria and express quorum-quenching enzymes to affect diverse bacteria in biofilm communities may become novel antifouling and antibiofilm agents in industrial and clinical settings. PMID:24951790

  2. Detection of Escherichia coli in drinking water using T7 bacteriophage-conjugated magnetic probe.

    Science.gov (United States)

    Chen, Juhong; Alcaine, Samuel D; Jiang, Ziwen; Rotello, Vincent M; Nugen, Sam R

    2015-09-01

    In this study, we demonstrate a bacteriophage (phage)-based magnetic separation scheme for the rapid detection of Escherichia coli (E. coli) in drinking water. T7 phage is a lytic phage with a broad host range specificity for E. coli. Our scheme was as follows: (1) T7 bacteriophage-conjugated magnetic beads were used to capture and separate E. coli BL21 from drinking water; (2) subsequent phage-mediated lysis was used to release endemic β-galactosidase (β-gal) from the bound bacterial cells; (3) the release of β-gal was detected using chlorophenol red-β-d-galactopyranoside (CRPG), a colorimetric substrate which changes from yellow to red in the presence of β-gal. Using this strategy, we were able to detect E. coli at a concentration of 1 × 10(4) CFU·mL(-1) within 2.5 h. The specificity of the proposed magnetic probes toward E. coli was demonstrated against a background of competing bacteria. By incorporating a pre-enrichment step in Luria-Bertani (LB) broth supplemented with isopropyl β-d-thiogalactopyranoside (IPTG), we were able to detect 10 CFU·mL(-1) in drinking water after 6 h of pre-enrichment. The colorimetric change can be determined either by visual observation or with a reader, allowing for a simple, rapid quantification of E. coli in resource-limited settings.

  3. Genetically Determined Variation in Lysis Time Variance in the Bacteriophage φX174.

    Science.gov (United States)

    Baker, Christopher W; Miller, Craig R; Thaweethai, Tanayott; Yuan, Jeffrey; Baker, Meghan Hollibaugh; Joyce, Paul; Weinreich, Daniel M

    2016-04-07

    Researchers in evolutionary genetics recently have recognized an exciting opportunity in decomposing beneficial mutations into their proximal, mechanistic determinants. The application of methods and concepts from molecular biology and life history theory to studies of lytic bacteriophages (phages) has allowed them to understand how natural selection sees mutations influencing life history. This work motivated the research presented here, in which we explored whether, under consistent experimental conditions, small differences in the genome of bacteriophage φX174 could lead to altered life history phenotypes among a panel of eight genetically distinct clones. We assessed the clones' phenotypes by applying a novel statistical framework to the results of a serially sampled parallel infection assay, in which we simultaneously inoculated each of a large number of replicate host volumes with ∼1 phage particle. We sequentially plated the volumes over the course of infection and counted the plaques that formed after incubation. These counts served as a proxy for the number of phage particles in a single volume as a function of time. From repeated assays, we inferred significant, genetically determined heterogeneity in lysis time and burst size, including lysis time variance. These findings are interesting in light of the genetic and phenotypic constraints on the single-protein lysis mechanism of φX174. We speculate briefly on the mechanisms underlying our results, and we discuss the potential importance of lysis time variance in viral evolution.

  4. Genetically Determined Variation in Lysis Time Variance in the Bacteriophage φX174

    Directory of Open Access Journals (Sweden)

    Christopher W. Baker

    2016-04-01

    Full Text Available Researchers in evolutionary genetics recently have recognized an exciting opportunity in decomposing beneficial mutations into their proximal, mechanistic determinants. The application of methods and concepts from molecular biology and life history theory to studies of lytic bacteriophages (phages has allowed them to understand how natural selection sees mutations influencing life history. This work motivated the research presented here, in which we explored whether, under consistent experimental conditions, small differences in the genome of bacteriophage φX174 could lead to altered life history phenotypes among a panel of eight genetically distinct clones. We assessed the clones’ phenotypes by applying a novel statistical framework to the results of a serially sampled parallel infection assay, in which we simultaneously inoculated each of a large number of replicate host volumes with ∼1 phage particle. We sequentially plated the volumes over the course of infection and counted the plaques that formed after incubation. These counts served as a proxy for the number of phage particles in a single volume as a function of time. From repeated assays, we inferred significant, genetically determined heterogeneity in lysis time and burst size, including lysis time variance. These findings are interesting in light of the genetic and phenotypic constraints on the single-protein lysis mechanism of φX174. We speculate briefly on the mechanisms underlying our results, and we discuss the potential importance of lysis time variance in viral evolution.

  5. Isolation and Characterization of a Virulent Bacteriophage φPA-HF17 of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Fang Han

    2014-09-01

    Full Text Available Pseudomonas aeruginosa, an important causative agent of nosocomial infection, is found throughout the hospital environment in moist reservoirs, and multidrug-resistant strains of P. aeruginosa have been increasingly reported worldwide. Bacteriophages are often considered potential therapeutic candidates in treating infectious diseases. In this study, a novel virulent bacteriophage φPA-HF17, specific infecting clinical isolates of P. aeruginosa, was isolated and characterized from environmental sewage. Transmission electron microscopy showed that phage φPA-HF17 had an icosahedral head with a very short tail, and exhibited characteristics typical of a podovirus. Restriction analysis indicated that phage φPA-HF17 was a double-stranded DNA virus, which might be digested by some restriction endonucleases. Phage φPA-HF17 was highly infectious with a rapid adsorption (>90% adsorbed in 4 min. In a one-step growth experiment, phage φPA-HF17 was shown having a latent period of 10 minute, with corresponding burst sizes of 200 PFU/cell. Furthermore, when φPA-HF17 alone was incubated at different pHs and different temperatures, the phage was stable over a wide pH range (4 to 10 and at extreme temperature (50°C. These results suggest that φPA-HF17 may be candidate therapeutic phage to control P. aeruginosa infection.

  6. Metagenomic analysis reveals that bacteriophages are reservoirs of antibiotic resistance genes.

    Science.gov (United States)

    Subirats, Jéssica; Sànchez-Melsió, Alexandre; Borrego, Carles M; Balcázar, José Luis; Simonet, Pascal

    2016-08-01

    A metagenomics approach was applied to explore the presence of antibiotic resistance genes (ARGs) in bacteriophages from hospital wastewater. Metagenomic analysis showed that most phage sequences affiliated to the order Caudovirales, comprising the tailed phage families Podoviridae, Siphoviridae and Myoviridae. Moreover, the relative abundance of ARGs in the phage DNA fraction (0.26%) was higher than in the bacterial DNA fraction (0.18%). These differences were particularly evident for genes encoding ATP-binding cassette (ABC) and resistance-nodulation-cell division (RND) proteins, phosphotransferases, β-lactamases and plasmid-mediated quinolone resistance. Analysis of assembled contigs also revealed that blaOXA-10, blaOXA-58 and blaOXA-24 genes belonging to class D β-lactamases as well as a novel blaTEM (98.9% sequence similarity to the blaTEM-1 gene) belonging to class A β-lactamases were detected in a higher proportion in phage DNA. Although preliminary, these findings corroborate the role of bacteriophages as reservoirs of resistance genes and thus highlight the necessity to include them in future studies on the emergence and spread of antibiotic resistance in the environment. PMID:27312355

  7. Inhibition of biofilm formation by T7 bacteriophages producing quorum-quenching enzymes.

    Science.gov (United States)

    Pei, Ruoting; Lamas-Samanamud, Gisella R

    2014-09-01

    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 polysaccharides and may have limited effects on natural multispecies biofilms. In this study, an engineered T7 bacteriophage was constructed to encode a lactonase enzyme with broad-range activity for quenching of quorum sensing, a form of bacterial cell-cell communication via small chemical molecules (acyl homoserine lactones [AHLs]) that is necessary for biofilm formation. Our results demonstrated that the engineered T7 phage expressed the AiiA lactonase to effectively degrade AHLs from many bacteria. Addition of the engineered T7 phage to mixed-species biofilms containing Pseudomonas aeruginosa and Escherichia coli resulted in inhibition of biofilm formation. Such quorum-quenching phages that can lyse host bacteria and express quorum-quenching enzymes to affect diverse bacteria in biofilm communities may become novel antifouling and antibiofilm agents in industrial and clinical settings. PMID:24951790

  8. Sequence characteristics of T4-like bacteriophage IME08 benome termini revealed by high throughput sequencing

    Directory of Open Access Journals (Sweden)

    An Xiaoping

    2011-04-01

    Full Text Available Abstract Background T4 phage is a model species that has contributed broadly to our understanding of molecular biology. T4 DNA replication and packaging share various mechanisms with human double-stranded DNA viruses such as herpes virus. The literature indicates that T4-like phage genomes have permuted terminal sequences, and are generated by a DNA terminase in a sequence-independent manner; Methods genomic DNA of T4-like bacteriophage IME08 was subjected to high throughput sequencing, and the read sequences with extraordinarily high occurrences were analyzed; Results we demonstrate that both the 5' and 3' termini of the IME08 genome starts with base G or A. The presence of a consensus sequence TTGGA|G around the breakpoint of the high frequency read sequences suggests that the terminase cuts the branched pre-genome in a sequence-preferred manner. Our analysis also shows that terminal cleavage is asymmetric, with one end cut at a consensus sequence, and the other end generated randomly. The sequence-preferred cleavage may produce sticky-ends, but with each end being packaged with different efficiencies; Conclusions this study illustrates how high throughput sequencing can be used to probe replication and packaging mechanisms in bacteriophages and/or viruses.

  9. Small regulatory RNAs in lambdoid bacteriophages and phage-derived plasmids: Not only antisense.

    Science.gov (United States)

    Nejman-Faleńczyk, Bożena; Bloch, Sylwia; Licznerska, Katarzyna; Felczykowska, Agnieszka; Dydecka, Aleksandra; Węgrzyn, Alicja; Węgrzyn, Grzegorz

    2015-03-01

    Until recently, only two small regulatory RNAs encoded by lambdoid bacteriophages were known. These transcripts are derived from paQ and pO promoters. The former one is supposed to act as an antisense RNA for expression of the Q gene, encoding a transcription antitermination protein. The latter transcript, called oop RNA, was initially proposed to have a double role, in establishing expression of the cI gene and in providing a primer for DNA replication. Although the initially proposed mechanisms by which oop RNA could influence the choice between two alternative developmental pathways of the phage and the initiation of phage DNA replication were found not true, the pO promoter has been demonstrated to be important for both regulation of phage development and control of DNA replication. Namely, the pO-derived transcript is an antisense RNA for expression of the cII gene, and pO is a part of a dual promoter system responsible for regulation of initiation of DNA synthesis from the oriλ region. Very recent studies identified a battery of small RNAs encoded by lambdoid bacteriophages existing as prophages in chromosomes of enterohemorrhagic Escherichia coli strains. Some of them have very interesting functions, like anti-small RNAs.

  10. APNTP Inactivation of MS2 Bacteriophage: Effect of operating parameters on virucidal activity

    Science.gov (United States)

    Alshraiedeh, Nid'a.; Alkawareek, Mahmoud; Gorman, Sean; Graham, William; Gilmore, Brendan

    2013-09-01

    Atmospheric pressure non-thermal plasmas (APNTP) provide a promising alternative method for surface decontamination. Norovirus is globally the most common etiological agent of acute non-bacterial gastroenteritis outbreaks. APNTP have proven to be effective in inactivation of MS2 bacteriophages, widely employed as surrogate for human norovirus. Here we explore the optimization of a helium-based kHz APNTP by varying the oxygen concentration (from 0 to 0.75%) in the feed gas and the operating frequency (from 10 to 40 kHz). It has been established that both these changes increase the reactive oxide concentration in the plume and we see a correlation between both increasing oxygen concentration and operating frequency and reduction in survival density of treated bacteriophages. For example increasing the O2 concentration from 0 to 0.5 to 0.75% increased the log reduction from 4.98 to 5.93 to 7.06, respectively. These results will be discussed in the context of recent studies where singlet delta oxygen was shown to cause MS2 phage inactivation., Q T Algwari, PhD Thesis QUB (2011).

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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-...

  9. 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.

  10. 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

  11. 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

  12. Isolation and partial characterization of a virulent bacteriophage IHQ1 specific for Aeromonas punctata from stream water.

    Science.gov (United States)

    Ul Haq, Irshad; Chaudhry, Waqas Nasir; Andleeb, Saadia; Qadri, Ishtiaq

    2012-05-01

    Aeromonas punctata is the causative agent of septicemia, diarrhea, wound infections, meningitis, peritonitis, and infections of the joints, bones and eyes. Bacteriophages are often considered alternative agents for controlling bacterial infection and contamination. In this study, we described the isolation and preliminary characterization of bacteriophage IHQ1 (family Myoviridae) active against the Gram-negative bacterial strain A. punctata. This virulent bacteriophage was isolated from stream water sample. Genome analysis indicated that phage IHQ1 was a double-stranded DNA virus with an approximate genome size of 25-28 kb. The initial characterization of this newly isolated phage showed that it has a narrow host range and infects only A. punctata as it failed to infect seven other clinically isolated pathogenic strains, i.e., methicillin-resistant Staphylococcus aureus 6403, MRSA 17644, Acinetobacter 33408, Acinetobacter 1172, Pseudomonas aeruginosa 22250, P. aeruginosa 11219, and Escherichia coli. Proteomic pattern of phage IHQ1, generated by SDS-PAGE using purified phage particles, showed three major and three minor protein bands with molecular weights ranging from 25 to 70 kDa. The adsorption rate of phage IHQ1 to the host bacterium was also determined, which was significantly enhanced by the addition of 10 mM CaCl(2). From the single-step growth experiment, it was inferred that the latent time period of phage IHQ1 was 24 min and a burst size of 626 phages per cell. Moreover, the pH and thermal stability of phage IHQ1 were also investigated. The maximum stability of the phage was observed at optimal pH 7.0, and it was totally unstable at extreme acidic pH 3; however, it was comparatively stable at alkaline pH 11.0. At 37°C the phage showed maximum number of plaques, and the viability was almost 100%. The existence of Aeromonas bacteriophage is very promising for the eradication of this opportunistic pathogen and also for future applications such as the

  13. Development of a new method for detection and identification of Oenococcus oeni bacteriophages based on endolysin gene sequence and randomly amplified polymorphic DNA.

    Science.gov (United States)

    Doria, Francesca; Napoli, Chiara; Costantini, Antonella; Berta, Graziella; Saiz, Juan-Carlos; Garcia-Moruno, Emilia

    2013-08-01

    Malolactic fermentation (MLF) is a biochemical transformation conducted by lactic acid bacteria (LAB) that occurs in wine at the end of alcoholic fermentation. Oenococcus oeni is the main species responsible for MLF in most wines. As in other fermented foods, where bacteriophages represent a potential risk for the fermentative process, O. oeni bacteriophages have been reported to be a possible cause of unsuccessful MLF in wine. Thus, preparation of commercial starters that take into account the different sensitivities of O. oeni strains to different phages would be advisable. However, currently, no methods have been described to identify phages infecting O. oeni. In this study, two factors are addressed: detection and typing of bacteriophages. First, a simple PCR method was devised targeting a conserved region of the endolysin (lys) gene to detect temperate O. oeni bacteriophages. For this purpose, 37 O. oeni strains isolated from Italian wines during different phases of the vinification process were analyzed by PCR for the presence of the lys gene, and 25 strains gave a band of the expected size (1,160 bp). This is the first method to be developed that allows identification of lysogenic O. oeni strains without the need for time-consuming phage bacterial-lysis induction methods. Moreover, a phylogenetic analysis was conducted to type bacteriophages. After the treatment of bacteria with UV light, lysis was obtained for 15 strains, and the 15 phage DNAs isolated were subjected to two randomly amplified polymorphic DNA (RAPD)-PCRs. By combining the RAPD profiles and lys sequences, 12 different O. oeni phages were clearly distinguished.

  14. 噬菌体在细菌性疾病诊断和治疗中的应用%Review of application of bacteriophage in the diagnosis and therapy for bacteria infection

    Institute of Scientific and Technical Information of China (English)

    苏胜兵; 马红霞; 徐凤宇

    2011-01-01

    从重组噬菌体法、生物扩增法、噬菌体触发的离子级联感应技术及耐药性检测4个方面阐述了噬菌体在病原菌检测中的作用;从细菌分型的角度阐述了噬菌体在病原菌分型中的应用;从活噬菌体、裂解酶、药物载体3个方面陈述了噬菌体在细菌性疾病治疗方法中的研究进展,并分析了噬菌体在应用中的优缺点,展望了今后的研究和应用前景.%This article reviews four kinds of detection technology for pathogen,including recombinant bacteriophage method, PhaB method, sensing of phage-triggered ion cascade technology, detection of the drug resistance. Meanwhile, the application of bacteriophage in typing bacteria was illustrated. Furthermore, the research advance in three means for treating bacterial diseases using bacteriophage was also summarized in this paper,including viable bacteriophage, lysin, drug carrier. The advantages and disadvantages of these three kinds of application were also elucidated. The prospective application and studies on bacteriophage were also proposed here.

  15. 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.

  16. 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

  17. [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.

  18. 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...

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. Complete genome sequence of Caulobacter crescentus bacteriophage φCbK.

    Science.gov (United States)

    Panis, Gaël; Lambert, Christophe; Viollier, Patrick H

    2012-09-01

    φCbK is a B3 morphotype bacteriophage of the Siphoviridae family that infects Caulobacter crescentus, the preeminent model system for bacterial cell cycle studies. The last 4 decades of research with φCbK as a genetic and cytological tool to study the biology of the host warrant an investigation of the phage genome composition. Herein, we report the complete genome sequence of φCbK and highlight unusual features that emerged from its annotation. The complete genome analysis of the φCbK phage provides new insight into its characteristics and potential interactions with its Caulobacter crescentus host, setting the stage for future functional studies with φCbK.

  6. 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

  7. Computer Simulations of DNA Packing inside Bacteriophages: Elasticity, Electrostatics and Entropy

    Directory of Open Access Journals (Sweden)

    D. Marenduzzo

    2008-01-01

    Full Text Available 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 packaging inside the phi29 phage, modelled either as a capped sphero-cylinder or as a sphere with the same internal volume. These simulations include electrostatics and a realistic genome length, and contribute to seriously questioning the inverse spool model, which arises from a purely continuum mechanics view of the problem, and is still commonly adopted to describe the shape of the packaged genome.

  8. Atomic force microscopy images of T4 bacteriophages on silicon substrates

    Energy Technology Data Exchange (ETDEWEB)

    Kolbe, W.F.; Ogletree, D.F.; Salmeron, M.B.

    1991-08-01

    A new atomic force microscope incorporating microfabricated cantilevers and employing laser beam deflection for force detection has been constructed and is being applied to studied of biological material. In this study, T4 bacteriophage virus particles were deposited from solution onto electronic grade flat silicon wafers and imaged in air with the microscope. Microliter droplets of the solution were deposited and either allowed to dry or removed with blotting paper. The images show both isolated viruses and aggregates of various sizes. The external structure as well as strands believed to be DNA streaming out of the virus could be observed. The construction of the microscope and its performance are also described. 19 refs., 4 figs.

  9. Recovery status of bacteriophages of different livestock farms of Veterinary College, Adhartal, Jabalpur, India

    Directory of Open Access Journals (Sweden)

    Sanjay Shukla and S. D. Hirpurkar

    2011-06-01

    Full Text Available Study was conducted to know the presence of bacteriophage in sewage material which can play a very important role during therapy against the some antibiotic resistance organisms. During study waste water samples were collected from different depths of the wastewater collection tanks located in livestock farms of different species (Cattle, pig, goat and poultry. These samples were subjected primarily to rapid detection by streak plate method for the detection of lytic activity followed by primary isolation of phage against two most common bacteria of environment, namely, B. subtilis and E. coli by Double agar layer (DAL method. Recovery of phages was maximum from pig feces (67% followed by dairy cattle farm waste (63%, buffalo farm waste (50%, goat farm waste (13%. [Vet. World 2011; 4(3.000: 117-119

  10. A bacteriophage endolysin-based electrochemical impedance biosensor for the rapid detection of Listeria cells.

    Science.gov (United States)

    Tolba, Mona; Ahmed, Minhaz Uddin; Tlili, Chaker; Eichenseher, Fritz; Loessner, Martin J; Zourob, Mohammed

    2012-12-21

    The objective of this study was to develop a biosensor using the cell wall binding domain (CBD) of bacteriophage-encoded peptidoglycan hydrolases (endolysin) immobilized on a gold screen printed electrode (SPE) and subsequent electrochemical impedance spectroscopy (EIS) for a rapid and specific detection of Listeria cells. The endolysin was amine-coupled to SPEs using EDC/NHS chemistry. The CBD-based electrode was used to capture and detect the Listeria innocua serovar 6b from pure culture and 2% artificially contaminated milk. In our study, the endolysin functionalized SPEs have been characterized using X-ray photoelectron spectroscopy (XPS). The integration of endolysin-based recognition for specific bacteria and EIS can be used for direct and rapid detection of Listeria cells with high specificity against non-Listeria cells with a limit of detection of 1.1 × 10(4) and 10(5) CFU mL(-1) in pure culture and 2% milk, respectively.

  11. Isolation and Characterization of a Virulent Bacteriophage AB1 of Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Jia Shiru

    2010-04-01

    Full Text Available Abstract Background Acinetobacter baumannii is an emerging nosocomial pathogen worldwide with increasing prevalence of multi-drug and pan-drug resistance. A. baumannii exists widely in natural environment, especially in health care settings, and has been shown difficult to be eradicated. Bacteriophages are often considered alternative agent for controlling bacterial infection and contamination. In this study, we described the isolation and characterization of one virulent bacteriophage AB1 capable of specifically infecting A. baumannii. Results A virulent bacteriophage AB1, specific for infecting a clinical strain A. baumannii KD311, was first isolated from marine sediment sample. Restriction analysis indicated that phage AB1 was a dsDNA virus with an approximate genome size of 45.2 kb to 46.9 kb. Transmission electron microscopy showed that phage AB1 had an icosahedral head with a non-contractile tail and collar or whisker structures, and might be tentatively classified as a member of the Siphoviridae family. Proteomic pattern of phage AB1, generated by SDS-PAGE using purified phage particles, revealed five major bands and six minor bands with molecular weight ranging from 14 to 80 kilo-dalton. Also determined was the adsorption rate of phage AB1 to the host bacterium, which was significantly enhanced by addition of 10 mM CaCl2. In a single step growth test, phage AB1 was shown having a latent period of 18 minutes and a burst size of 409. Moreover, pH and thermal stability of phage AB1 were also investigated. At the optimal pH 6.0, 73.2% of phages survived after 60 min incubation at 50°C. When phage AB1 was used to infect four additional clinical isolates of A. baumannii, one clinical isolate of Stenotrophomonas maltophilia, and Pseudomonas aeruginosa lab strains PAK and PAO1, none of the tested strains was found susceptible, indicating a relatively narrow host range for phage AB1. Conclusion Phage AB1 was capable of eliciting efficient lysis

  12. Development and validation of a methodology for determining the concentration of bacteriophages of enteric bacteria in drinking water; Desarrollo y validacion de una metodologia de concentracion de bacteriofagos de bacterias entericas en aguas de bebida

    Energy Technology Data Exchange (ETDEWEB)

    Mendez, J.; Audicana, A.; Cancer, M.; Isern, A.; Llaneza, J.; Moreno, B.; Navarro, M.; Sesma, B.; Tarancon, M. L.; Jofre, J.; Lucena, F.

    2004-07-01

    A method has been developed for determining the concentration of bacteriophages in drinking water involving a primary validation followed by a secondary validation in collaboration with various public health laboratories. The secondary validation involved coordinating and transferring both the methodologies for detecting and enumerating phages, and the method for determining concentrations, to the laboratories, which had never routinely worked with bacteriophages before. The results obtained reveal the possibility of transferring these methodologies to public health laboratories and show how validated protocols and methods can be transferred in order to obtain more reliable results in microbiology studies of water. (Author)

  13. Inactivation of adenovirus, reovirus and bacteriophages in fecal sludge by pH and ammonia.

    Science.gov (United States)

    Magri, Maria Elisa; Fidjeland, Jørgen; Jönsson, Håkan; Albihn, Ann; Vinnerås, Björn

    2015-07-01

    The aim of this study was to evaluate the inactivation of adenovirus, reovirus and bacteriophages (MS2, ΦX174, 28B) in a fecal sludge. We conducted two experiments. In the first, we tested different compositions of the fecal sludge by mixing different amounts of water, feces and urine, totaling nine combinations which were kept at temperatures between 10 and 28°C. In the second study, urea was added to the mixtures, which were kept at temperatures from 5 to 33°C. The inactivation was based on a combination of temperature, pH and uncharged ammonia concentration. The increase in pH and ammonia was provided mainly by urine content (Experiment 1) and by urine and added urea (Experiment 2). The inactivation of bacteriophages was slower than the AdV and ReV. At 23°C and 28°, reasonable treatment times were obtained when pH was higher than 8.9 and NH3 concentrations were higher than 35 and 55 mM respectively. With those conditions, the maximum time for a 3 log reduction in viruses, according to this study, would be 35 days (23°C) and 21 days (28°C). However, in most applications where helminth eggs are present, the treatment time and NH3 for sanitization will be the scaling criteria, as they are more persistent. Concerning the sanitization of effluents from latrines, vacuum toilets or dry toilets in developing countries with tropical and sub-tropical climates, the use of intrinsic ammonia combined with high pH can be effective in producing a safe and highly valuable liquid that can be used as a fertilizer. In the case of the fecal sludge with very intrinsic ammonia concentration (<20 mM), sanitization could still be achieved by the addition of urea.

  14. 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.

  15. 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.

  16. 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.

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

    Science.gov (United States)

    Grose, Julianne H.; Casjens, Sherwood R.

    2014-01-01

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

  18. Structure, Dynamics, and Assembly of Filamentous Bacteriophages by Nuclear Magnetic Resonance Spectroscopy

    Science.gov (United States)

    Opella, Stanley J.; Zeri, Ana Carolina; Park, Sang Ho

    2008-05-01

    Filamentous bacteriophages serve as model systems for the development and implementation of spectroscopic methods suitable for biological supramolecular assemblies. Not only are their coat proteins small and readily prepared in the laboratory, but they also have two primary roles as membrane proteins and as the principal structural element of the virus particles. As a bacterial system, they are readily labeled with stable isotopes, and this has opened possibilities for the many nuclear magnetic resonance (NMR) studies described in this review. In particular, solid-state NMR of aligned samples has been used to determine the three-dimensional structures of both the membrane-bound forms of coat proteins in phospholipid bilayers and structural forms in virus particles, which has led to an analysis of the assembly mechanism for virus particles as they are extruded through the cell membrane.

  19. Oxygen effect in bacteriophages irradiated in different media. 1. Irradiation in salt solution

    Energy Technology Data Exchange (ETDEWEB)

    Korystov, Yu.N.; Veksler, F.B. (AN SSSR, Pushchino-na-Oke. Inst. Biologicheskoj Fiziki)

    1983-09-14

    The oxygen effect (OE) on bacteriophage T4 in a salt solution was studied. It is shown that the sign and magnitude of OE depend on the conditions of the postirradiation incubation of the phage in irradiated medium. The direct OE is due to postirradiation lesion of the phage by hydrogen peroxide which is formed in greater amounts after irradiation in oxygen than in anoxia. The addition of catalase is shown to eliminate the postirradiation inactivation of the phage. In this case an opposite OE is observed. The mechanism of this effect is a scavenge of hydrogen atoms which damage the phage by oxygen. In the presence of catalase the OE depends also on pH of the solution. It is suggested that the hydroxyl radical arising from the reaction of H/sub 2/O/sub 2/ with Fe/sup 2 +/ is responsible for the damaging effect of H/sub 2/O/sub 2/.

  20. Proteomic Characterization of Lytic Bacteriophages of Staphylococcus aureus Isolated from Sewage Affluent of India

    Science.gov (United States)

    Sangha, Kamalpreet Kaur; Kumar, B. V. Sunil; Agrawal, Ravi Kant; Verma, Ramneek

    2014-01-01

    Staphylococcus aureus is a Gram-positive bacterium that causes a variety of diseases, including bovine mastitis, which has severe economic consequences. Standard antibiotic treatment results in selection of resistant strains, leading to need for an alternative treatment such as bacteriophage therapy. Present study describes isolation and characterization of a staphylococcal phage from sewage samples. S. aureus isolates obtained from microbial type culture collection (MTCC), Chandigarh, India, were used to screen staphylococcal phages. A phage designated as ΦMSP was isolated from sewage samples by soft agar overlay method. It produced clear plaques on tryptone soya agar overlaid with S. aureus. Transmission electron microscopy revealed that the phage had an icosahedral symmetry. It had 5 major proteins and possessed a peptidoglycan hydrolase corresponding to 70 kDa. ΦMSP infection induced 26 proteins to be uniquely expressed in S. aureus. This phage can be proposed as a candidate phage to treat staphylococcal infections. PMID:27355013

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

    Science.gov (United States)

    Grose, Julianne H; Casjens, Sherwood R

    2014-11-01

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

  2. Pathological and therapeutic interactions between bacteriophages, microbes and the host in inflammatory bowel disease.

    Science.gov (United States)

    Babickova, Janka; Gardlik, Roman

    2015-10-28

    The intestinal microbiome is a dynamic system of interactions between the host and its microbes. Under physiological conditions, a fine balance and mutually beneficial relationship is present. Disruption of this balance is a hallmark of inflammatory bowel disease (IBD). Whether an altered microbiome is the consequence or the cause of IBD is currently not fully understood. The pathogenesis of IBD is believed to be a complex interaction between genetic predisposition, the immune system and environmental factors. In the recent years, metagenomic studies of the human microbiome have provided useful data that are helping to assemble the IBD puzzle. In this review, we summarize and discuss current knowledge on the composition of the intestinal microbiota in IBD, host-microbe interactions and therapeutic possibilities using bacteria in IBD. Moreover, an outlook on the possible contribution of bacteriophages in the pathogenesis and therapy of IBD is provided.

  3. A Novel Shiga Toxin 1a-Converting Bacteriophage of Shigella sonnei With Close Relationship to Shiga Toxin 2-Converting Pages of Escherichia coli.

    Science.gov (United States)

    Carter, Christoph C; Fierer, Joshua; Chiu, Wei Wei; Looney, David J; Strain, Matthew; Mehta, Sanjay R

    2016-04-01

    In recent studies, strains of non-dysenteriae 1 Shigella (NDS) expressing Shiga toxin have been reported. In this study, we report a novel stx1a-converting bacteriophage of Shigella sonnei associated with travel to Mexico. Phylogenetic comparison between this and other stx-converting phages suggests that toxigenic NDS strains have arisen through separate horizontal transfer events from toxigenic Escherichia coli. PMID:27419156

  4. 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

  5. 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.

  6. Antibiotic resistance genes in the bacteriophage DNA fraction of environmental samples.

    Directory of Open Access Journals (Sweden)

    Marta Colomer-Lluch

    Full Text Available Antibiotic resistance is an increasing global problem resulting from the pressure of antibiotic usage, greater mobility of the population, and industrialization. Many antibiotic resistance genes are believed to have originated in microorganisms in the environment, and to have been transferred to other bacteria through mobile genetic elements. Among others, β-lactam antibiotics show clinical efficacy and low toxicity, and they are thus widely used as antimicrobials. Resistance to β-lactam antibiotics is conferred by β-lactamase genes and penicillin-binding proteins, which are chromosomal- or plasmid-encoded, although there is little information available on the contribution of other mobile genetic elements, such as phages. This study is focused on three genes that confer resistance to β-lactam antibiotics, namely two β-lactamase genes (blaTEM and blaCTX-M9 and one encoding a penicillin-binding protein (mecA in bacteriophage DNA isolated from environmental water samples. The three genes were quantified in the DNA isolated from bacteriophages collected from 30 urban sewage and river water samples, using quantitative PCR amplification. All three genes were detected in the DNA of phages from all the samples tested, in some cases reaching 104 gene copies (GC of blaTEM or 102 GC of blaCTX-M and mecA. These values are consistent with the amount of fecal pollution in the sample, except for mecA, which showed a higher number of copies in river water samples than in urban sewage. The bla genes from phage DNA were transferred by electroporation to sensitive host bacteria, which became resistant to ampicillin. blaTEM and blaCTX were detected in the DNA of the resistant clones after transfection. This study indicates that phages are reservoirs of resistance genes in the environment.

  7. Probing the viral metallome: searching for metalloproteins in bacteriophage λ-- the hunt begins.

    Science.gov (United States)

    Zhang, Yaofang; Thompson, Richard; Caruso, Joseph

    2011-05-01

    Although the proteome and genome of bacteriophages are well developed, there is little knowledge about metals and their interactions with the phages, even though metals have been observed in stabilizing phage particles. With expanding studies of phage display and its promising applications, metalloprotein investigations in the bacteriophage areas are necessary to understand whether or not metalloproteins are included in the viral coat proteome. Since these virus studies are still in their infancy, lambda phage was chosen due to its high metal-binding potential as suggested by the cysteine/methionine rich proteins in the viral coat. After large-scale preparation and further purification of lambda phage according to standard protocols, state-of-the-art metallomics techniques via combinations of chromatographies and mass spectrometries were utilized for screening metal-associated species in lambda phage. The lambda phage sample was first separated using non-denaturing size exclusion chromatography with selective metal detection by ICPMS for screening associated metals and generating size distribution fractions for the various metal species, some of which include metalloproteins. Various molecular size distribution patterns were exhibited for the metals detected, Mn, Fe, Co, Ni, Cu and Zn, at different molecular weight ranges. On the other hand numerous other metals were not associated with the coat proteins, as they were not detected in the different molecular weight fractions. Further identification for putative metallopeptides and metalloproteins was accomplished by collecting various metal species' fractions offline and subsequently analyzing tryptically-digested fractions via nanoLC-Chip-ESI-MS. By searching appropriate MS databases with both Spectrum Mill and MASCOT search engines, the main capsid protein, gpE, a capsid decoration protein, gpD, and main tail component protein, gpV, were found and are known for associations with the detected transition metals

  8. The genetic switch regulating activity of early promoters of the temperate lactococcal bacteriophage TP901-1

    DEFF Research Database (Denmark)

    Madsen, P.L.; Johansen, Annette Helle; Hammer, Karin;

    1999-01-01

    A functional analysis of open reading frame 4 (ORF4) and ORF5 from the temperate lactococcal phage TP901-1 was performed by mutant and deletion analysis combined with transcriptional studies of the early phage promoters p(R) and p(L). ORF4 (180 amino acids) was identified as a phage repressor nec...... or lysogenic life cycle after phage infection and that a protein complex consisting of ORF4 and ORF5 may constitute a new type of genetic switch in bacteriophages....

  9. Application of bacteriophages to reduce biofilms formed by hydrogen sulfide producing bacteria on surfaces in a rendering plant.

    Science.gov (United States)

    Gong, Chao; Jiang, Xiuping

    2015-08-01

    Hydrogen sulfide producing bacteria (SPB) in raw animal by-products are likely to grow and form biofilms in the rendering processing environments, resulting in the release of harmful hydrogen sulfide (H2S) gas. The objective of this study was to reduce SPB biofilms formed on different surfaces typically found in rendering plants by applying a bacteriophage cocktail. Using a 96-well microplate method, we determined that 3 SPB strains of Citrobacter freundii and Hafnia alvei are strong biofilm formers. Application of 9 bacteriophages (10(7) PFU/mL) from families of Siphoviridae and Myoviridae resulted in a 33%-70% reduction of biofilm formation by each SPB strain. On stainless steel and plastic templates, phage treatment (10(8) PFU/mL) reduced the attached cells of a mixed SPB culture (no biofilm) by 2.3 and 2.7 log CFU/cm(2) within 6 h at 30 °C, respectively, as compared with 2 and 1.5 log CFU/cm(2) reductions of SPB biofilms within 6 h at 30 °C. Phage treatment was also applied to indigenous SPB biofilms formed on the environmental surface, stainless steel, high-density polyethylene plastic, and rubber templates in a rendering plant. With phage treatment (10(9) PFU/mL), SPB biofilms were reduced by 0.7-1.4, 0.3-0.6, and 0.2-0.6 log CFU/cm(2) in spring, summer, and fall trials, respectively. Our study demonstrated that bacteriophages could effectively reduce the selected SPB strains either attached to or in formed biofilms on various surfaces and could to some extent reduce the indigenous SPB biofilms on the surfaces in the rendering environment.

  10. 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...

  11. 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.

  12. Receptor diversity and host interaction of bacteriophages infecting Salmonella enterica serovar Typhimurium.

    Directory of Open Access Journals (Sweden)

    Hakdong Shin

    Full Text Available BACKGROUND: Salmonella enterica subspecies enterica serovar Typhimurium is a gram-negative pathogen causing salmonellosis. Salmonella Typhimurium-targeting bacteriophages have been proposed as an alternative biocontrol agent to antibiotics. To further understand infection and interaction mechanisms between the host strains and the bacteriophages, the receptor diversity of these phages needs to be elucidated. METHODOLOGY/PRINCIPAL FINDINGS: Twenty-five Salmonella phages were isolated and their receptors were identified by screening a Tn5 random mutant library of S. Typhimurium SL1344. Among them, three types of receptors were identified flagella (11 phages, vitamin B(12 uptake outer membrane protein, BtuB (7 phages and lipopolysaccharide-related O-antigen (7 phages. TEM observation revealed that the phages using flagella (group F or BtuB (group B as a receptor belong to Siphoviridae family, and the phages using O-antigen of LPS as a receptor (group L belong to Podoviridae family. Interestingly, while some of group F phages (F-I target FliC host receptor, others (F-II target both FliC and FljB receptors, suggesting that two subgroups are present in group F phages. Cross-resistance assay of group B and L revealed that group L phages could not infect group B phage-resistant strains and reversely group B phages could not infect group L SPN9TCW-resistant strain. CONCLUSIONS/SIGNIFICANCE: In this report, three receptor groups of 25 newly isolated S. Typhimurium-targeting phages were determined. Among them, two subgroups of group F phages interact with their host receptors in different manner. In addition, the host receptors of group B or group L SPN9TCW phages hinder other group phage infection, probably due to interaction between receptors of their groups. This study provides novel insights into phage-host receptor interaction for Salmonella phages and will inform development of optimal phage therapy for protection against Salmonella.

  13. Characterization of a virulent bacteriophage LK1 specific for Citrobacter freundii isolated from sewage water.

    Science.gov (United States)

    Chaudhry, Waqas Nasir; Haq, Irshad Ul; Andleeb, Saadia; Qadri, Ishtiaq

    2014-06-01

    Citrobacter freundii is a worldwide emerging nosocomial pathogen with escalating incidence of multidrug resistance. Citrobacter freundii exists in natural environment, especially in health care settings and is difficult to eradicate. Phage therapy is considered as an alternative way of controlling bacterial infections and contaminations. In this study, we have described isolation and characterization of a virulent bacteriophage LK1 capable of specifically infecting Citrobacter freundii. A virulent bacteriophage LK1, specific for Citrobacter freundii was isolated from sewage water sample. TEM showed that phage Lk1 has an icosahedral head 70 nm in diameter and short tail of 17 nm, and can be classified as a member of the Podoviridae family. Restriction analysis indicated that phage LK1 was a dsDNA virus with an approximate genome size of 20-23 kb. Proteomic pattern generated by SDS PAGE using purified LK1 phage particles, revealed three major and six minor protein bands with molecular weight ranging from 25 to 80 kDa. Adsorption rate of LK1 relative to the host bacterium was also determined which showed significant improvement in adsorption with the addition of CaCl2 . In a single step growth experiment, LK1 exhibited a latent period of 24 min and burst size of 801 particle/cell. Moreover, pH and thermal stability of phage LK1 demonstrated a pH range of 5.0-6.0 and phage viability decreased to 0% at 65 °C. When LK1 was used to infect six other clinically isolated pathogenic strains, it showed relatively narrow host range. LK1 was capable of eliciting efficient lysis of Citrobacter freundii, revealing its potential as a non-toxic sanitizer for controlling Citrobacter freundii infection and contamination in both hospital and other public environments.

  14. A modified MS2 bacteriophage plaque reduction assay for the rapid screening of antiviral plant extracts

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    Ian Cock

    2010-01-01

    Full Text Available Introduction: Traditional methods of screening plant extracts and purified components for antiviral activity require up to a week to perform, prompting the need to develop more rapid quantitative methods to measure the ability of plant based preparations to block viral replication. We describe an adaption of an MS2 plaque reduction assay for use in S. aureus. Results: MS2 bacteriophage was capable of infecting and replicating in B. cereus, S. aureus and F+ E. coli but not F- E. coli. Indeed, both B. cereus and S. aureus were more sensitive to MS2 induced lysis than F+ E. coli. When MS2 bacteriophage was mixed with Camellia sinensis extract (1 mg/ml, Scaevola spinescens extract (1 mg/ml or Aloe barbadensis juice and the mixtures inoculated into S. aureus, the formation of plaques was reduced to 8.9 ± 3.8%, 5.4 ± 2.4% and 72.7 ± 20.9% of the untreated MS2 control values respectively. Conclusions: The ability of the MS2 plaque reduction assay to detect antiviral activity in these known antiviral plant preparations indicates its suitability as an antiviral screening tool. An advantage of this assay compared with traditionally used cytopathic effect reduction assays and replicon based assays is the more rapid acquisition of results. Antiviral activity was detected within 24 h of the start of testing. The MS2 assay is also inexpensive and non-pathogenic to humans making it ideal for initial screening studies or as a simulant for pathogenic viruses.

  15. Using lytic bacteriophages to eliminate or significantly reduce contamination of food by foodborne bacterial pathogens.

    Science.gov (United States)

    Sulakvelidze, Alexander

    2013-10-01

    Bacteriophages (also called 'phages') are viruses that kill bacteria. They are arguably the oldest (3 billion years old, by some estimates) and most ubiquitous (total number estimated to be 10(30) -10(32) ) known organisms on Earth. Phages play a key role in maintaining microbial balance in every ecosystem where bacteria exist, and they are part of the normal microflora of all fresh, unprocessed foods. Interest in various practical applications of bacteriophages has been gaining momentum recently, with perhaps the most attention focused on using them to improve food safety. That approach, called 'phage biocontrol', typically includes three main types of applications: (i) using phages to treat domesticated livestock in order to reduce their intestinal colonization with, and shedding of, specific bacterial pathogens; (ii) treatments for decontaminating inanimate surfaces in food-processing facilities and other food establishments, so that foods processed on those surfaces are not cross-contaminated with the targeted pathogens; and (iii) post-harvest treatments involving direct applications of phages onto the harvested foods. This mini-review primarily focuses on the last type of intervention, which has been gaining the most momentum recently. Indeed, the results of recent studies dealing with improving food safety, and several recent regulatory approvals of various commercial phage preparations developed for post-harvest food safety applications, strongly support the idea that lytic phages may provide a safe, environmentally-friendly, and effective approach for significantly reducing contamination of various foods with foodborne bacterial pathogens. However, some important technical and nontechnical problems may need to be addressed before phage biocontrol protocols can become an integral part of routine food safety intervention strategies implemented by food industries in the USA.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. Expression of Recombinant pET22b-LysK-Cysteine/Histidine-Dependent Amidohydrolase/Peptidase Bacteriophage Therapeutic Protein in Escherichia coli BL21 (DE3)

    OpenAIRE

    Kashani, Hamed Haddad; Moniri, Rezvan

    2015-01-01

    Objectives Bacteriophage-encoded endolysins are a group of enzymes that act by digesting the peptidoglycan of bacterial cell walls. LysK has been reported to lyse live staphylococcal cultures. LysK proteins containing only the cysteine/histidine-dependent amidohydrolase/peptidase (CHAP) domain has the capability to show lytic activity against live clinical staphylococcal isolates, including methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study was to clone and express LysK...

  5. Comparative study of the resistance of bacteriophageT4,ΦX174D,MS2 and f2 to gamma radiation%T4、ΦX174D、MS2和f2噬菌体对γ射线抵抗力的比较研究

    Institute of Scientific and Technical Information of China (English)

    陈昭斌; 黄红英; 张朝武

    2008-01-01

    目的 为筛选出辐照灭菌中评价对病毒灭活效果的指示噬菌体,比较研究了噬菌体T4、φX174D、MS2和f2,以及两种细菌参考株大肠杆菌8099和枯草杆菌黑色变种芽孢ATCC 9372对电离辐射γ射线的抵抗力.方法 采用钴源60Co-γ射线辐射源对噬菌体和细菌进行辐照处理;灭活方法采用悬液灭活试验;噬菌体的检测采用双层琼脂法.结果 方差分析表明,不同剂量的γ射线组间(P<0.01)和不同的噬菌体组间(P<0.05),差异均有统计学意义.LIV(灭活对数值)和KL(杀灭对数值)为:(1)T4、ΦX174、f2和MS2 4种噬菌体经100 Gy的γ射线辐照可达到消毒水平(LIV≥4.00 log10);在此剂量下4种噬菌体的LIV分别为:6.31,6.92,5.74和4.46 log10;(2)在前述剂量下,大肠杆菌8099的KL>7.97 log10;(3)在前述剂量下,枯草杆菌黑色变种芽孢ATCC9372的KL为1.61 log10.结论 6种微生物对γ射线的抵抗力由强到弱为:枯草杆菌黑色变种芽孢>噬菌体MS2>噬菌体f2>噬菌体T4>噬菌体φX174>大肠杆菌.%Objective To screen the suitable bacteriophage as virus indictor in irradiation sterilization.Methods Suspensions of bacteriophage T4,φX174D,MS2,and f2,Escherichia coli 8099,and Bacillus subtilis var. niger.sp.ATCC9372 were irradiated with60 Co-γ ray.The mean log10 inactivation value levels of the bacteriophage T4,ΦX174,f2,and MS2 were 6.31,6.92,5.74,and 4.46 log10 respectively,var.niger.sp.ATCC9372 was 1.61 log10.Conclusion The order of resistance of the above six microorganisms to gamma-radiation from the biggest to the smallest iS as follows:Bacillus subtilis var.niger.sp.>bacteriophage MS2>bacteriophage f2>bacteriophage T4>bacteriophage φX 174D>E. coli.

  6. Occurrence of bacteriophages infecting Bacteroides host strains (ARABA 84 and GB-124) in fecal samples of human and animal origin.

    Science.gov (United States)

    Diston, David; Wicki, Melanie

    2015-09-01

    Bacteriophage-based microbial source-tracking studies are an economical and simple way of identifying fecal sources in polluted water systems. Recently isolated Bacteroides spp. strains ARABA 84, and GB-124 have been shown to detect bacteriophages exclusively in aquatic systems impacted by human fecal material. To date, limited examination of the occurrence or concentration of phages capable of infecting Bacteroides fragilis strain GB-124 or B. thetaiotaomicron strain ARABA 84 in human and animal feces has been carried out. This study reports the prevalence rates and concentrations of phages infecting ARABA 84 and GB-124 host strains in human and a range of animal feces. Discrete human fecal samples (n=55) and pooled animal samples (n=46, representing the feces of over 230 animals) were examined for phages infecting the host strains ARABA 84, GB-124, and E. coli strain WG5. Both human Bacteroides host strains were highly specific (95% and 100% for ARABA 84 and GB-124, respectively), challenging results from previous studies. This study supports the use of Bacteroides strains GB-124 and ARABA 84 in fecal source tracking studies for the detection of human fecal contamination.

  7. 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

  8. Exploring the Symmetry and Mechanism of Virus Capsid Maturation Via an Ensemble of Pathways

    OpenAIRE

    May, Eric R.; Feng, Jun; Brooks, Charles L.

    2012-01-01

    Many icosahedral viruses undergo large-scale conformational transitions between icosahedrally symmetric conformations during their life cycles. However, whether icosahedral symmetry is maintained along the transition pathways for this process is unknown. By employing a simplified and directed structure-based potential we compute an ensemble of transition pathways for the maturation transition of bacteriophage HK97. We observe localized symmetry-breaking events, but find that the large-scale d...

  9. 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...

  10. [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.

  11. 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.

  12. 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.

  13. 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.

  14. Removal of particle-associated bacteriophages by dual-media filtration at different filter cycle stages and impacts on subsequent UV disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Templeton, M.R.; Andrews, R.C.; Hofmann, R. [University of Toronto, Toronto, ON (Canada). Dept. of Civil Engineering

    2007-06-15

    This bench-scale study investigated the passage of particle-associated bacteriophage through a dual-media (anthracite-sand) filter over a complete filter cycle and the effect on subsequent ultraviolet (UV) disinfection. Two model viruses, bacteriophages MS2 and T4, were considered. The water matrix was de-chlorinated tap water with either kaolin or Aldrich humic acid (AHA) added and coagulated with alum to form floc before filtration. Filter effluent samples were collected for phage enumeration during three filter cycle stages: (I) filter ripening; (ii) stable operation; and (iii) end of filter cycle. Influent and filter effluent samples were subsequently exposed to UV light (254 nm) at 40 mJ/cm{sup 2} using a low pressure UV collimated beam. The study found statistically significant differences ({alpha} = 0.05) in the quantity of particle-associated phage present in the filter effluent during the three stages of filtration. There was reduced UV disinfection efficiency due to the presence of particle- associated phage in the filter effluent in trials with bacteriophage MS2 and humic acid floc. Unfiltered influent water samples also resulted in reduced UV inactivation of phage relative to particle-free control conditions for both phages. Trends in filter effluent turbidity corresponded with breakthrough of particle-associated phage in the filter effluent. The results therefore suggest that maintenance of optimum filtration conditions upstream of UV disinfection is a critical barrier to particle-associated viruses.

  15. 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....

  16. 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....

  17. 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.

  18. 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...

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. Reduction of Salmonella on chicken breast fillets stored under aerobic or modified atmosphere packaging by the application of lytic bacteriophage preparation SalmoFreshTM.

    Science.gov (United States)

    Sukumaran, Anuraj T; Nannapaneni, Rama; Kiess, Aaron; Sharma, Chander Shekhar

    2016-03-01

    The present study evaluated the efficacy of recently approved Salmonella lytic bacteriophage preparation (SalmoFresh™) in reducing Salmonella on chicken breast fillets, as a surface and dip application. The effectiveness of phage in combination with modified atmosphere packaging (MAP) and the ability of phage preparation in reducing Salmonella on chicken breast fillets at room temperature was also evaluated. Chicken breast fillets inoculated with a cocktail of Salmonella Typhimurium, S. Heidelberg, and S. Enteritidis were treated with bacteriophage (10(9) PFU/mL) as either a dip or surface treatment. The dip-treated samples were stored at 4°C aerobically and the surface-treated samples were stored under aerobic and MAP conditions (95% CO2/5% O2) at 4°C for 7 d. Immersion of Salmonella-inoculated chicken breast fillets in bacteriophage solution reduced Salmonella (P chicken breast fillets when the samples were surface treated with phage and stored under MAP conditions. The Salmonella counts were reduced by 1.2, 1.1, and 1.2 log CFU/g on d 0, 1, and 7 of storage, respectively. Bacteriophage surface application on chicken breast fillets stored at room temperature reduced the Salmonella counts by 0.8, 0.9, and 0.4 log CFU/g after 0, 4, and 8 h, respectively, compared to the untreated positive control. These findings indicate that lytic phage preparation was effective in reducing Salmonella on chicken breast fillets stored under aerobic and modified atmosphere conditions.

  4. 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...

  5. Genome, Proteome and Structure of a T7-Like Bacteriophage of the Kiwifruit Canker Phytopathogen Pseudomonas Syringae pv. Actinidiae

    Directory of Open Access Journals (Sweden)

    Rebekah A. Frampton

    2015-06-01

    Full Text Available Pseudomonas syringae pv. actinidiae is an economically significant pathogen responsible for severe bacterial canker of kiwifruit (Actinidia sp.. Bacteriophages infecting this phytopathogen have potential as biocontrol agents as part of an integrated approach to the management of bacterial canker, and for use as molecular tools to study this bacterium. A variety of bacteriophages were previously isolated that infect P. syringae pv. actinidiae, and their basic properties were characterized to provide a framework for formulation of these phages as biocontrol agents. Here, we have examined in more detail φPsa17, a phage with the capacity to infect a broad range of P. syringae pv. actinidiae strains and the only member of the Podoviridae in this collection. Particle morphology was visualized using cryo-electron microscopy, the genome was sequenced, and its structural proteins were analysed using shotgun proteomics. These studies demonstrated that φPsa17 has a 40,525 bp genome, is a member of the T7likevirus genus and is closely related to the pseudomonad phages φPSA2 and gh-1. Eleven structural proteins (one scaffolding were detected by proteomics and φPsa17 has a capsid of approximately 60 nm in diameter. No genes indicative of a lysogenic lifecycle were identified, suggesting the phage is obligately lytic. These features indicate that φPsa17 may be suitable for formulation as a biocontrol agent of P. syringae pv. actinidiae.

  6. Genome, Proteome and Structure of a T7-Like Bacteriophage of the Kiwifruit Canker Phytopathogen Pseudomonas syringae pv. actinidiae.

    Science.gov (United States)

    Frampton, Rebekah A; Acedo, Elena Lopez; Young, Vivienne L; Chen, Danni; Tong, Brian; Taylor, Corinda; Easingwood, Richard A; Pitman, Andrew R; Kleffmann, Torsten; Bostina, Mihnea; Fineran, Peter C

    2015-07-01

    Pseudomonas syringae pv. actinidiae is an economically significant pathogen responsible for severe bacterial canker of kiwifruit (Actinidia sp.). Bacteriophages infecting this phytopathogen have potential as biocontrol agents as part of an integrated approach to the management of bacterial canker, and for use as molecular tools to study this bacterium. A variety of bacteriophages were previously isolated that infect P. syringae pv. actinidiae, and their basic properties were characterized to provide a framework for formulation of these phages as biocontrol agents. Here, we have examined in more detail φPsa17, a phage with the capacity to infect a broad range of P. syringae pv. actinidiae strains and the only member of the Podoviridae in this collection. Particle morphology was visualized using cryo-electron microscopy, the genome was sequenced, and its structural proteins were analysed using shotgun proteomics. These studies demonstrated that φPsa17 has a 40,525 bp genome, is a member of the T7likevirus genus and is closely related to the pseudomonad phages φPSA2 and gh-1. Eleven structural proteins (one scaffolding) were detected by proteomics and φPsa17 has a capsid of approximately 60 nm in diameter. No genes indicative of a lysogenic lifecycle were identified, suggesting the phage is obligately lytic. These features indicate that φPsa17 may be suitable for formulation as a biocontrol agent of P. syringae pv. actinidiae. PMID:26114474

  7. Reduction of Salmonella on chicken breast fillets stored under aerobic or modified atmosphere packaging by the application of lytic bacteriophage preparation SalmoFreshTM.

    Science.gov (United States)

    Sukumaran, Anuraj T; Nannapaneni, Rama; Kiess, Aaron; Sharma, Chander Shekhar

    2016-03-01

    The present study evaluated the efficacy of recently approved Salmonella lytic bacteriophage preparation (SalmoFresh™) in reducing Salmonella on chicken breast fillets, as a surface and dip application. The effectiveness of phage in combination with modified atmosphere packaging (MAP) and the ability of phage preparation in reducing Salmonella on chicken breast fillets at room temperature was also evaluated. Chicken breast fillets inoculated with a cocktail of Salmonella Typhimurium, S. Heidelberg, and S. Enteritidis were treated with bacteriophage (10(9) PFU/mL) as either a dip or surface treatment. The dip-treated samples were stored at 4°C aerobically and the surface-treated samples were stored under aerobic and MAP conditions (95% CO2/5% O2) at 4°C for 7 d. Immersion of Salmonella-inoculated chicken breast fillets in bacteriophage solution reduced Salmonella (P effective in reducing Salmonella on chicken breast fillets stored under aerobic and modified atmosphere conditions. PMID:26706362

  8. Effect of bacteriophage lysin on lysogens

    Institute of Scientific and Technical Information of China (English)

    Balaji Subramanyam; Vanaja Kumar

    2011-01-01

    Objective: To study the effect of phage lysin on the growth of lysogens. Methods: Sputum specimens processed by modified Petroff's method were respectively treated with phagebiotics in combination with lysin and lysin alone. The specimens were incubated at 37℃ for 4 days. At the end of day 1, 2, 3 and day 4, the specimens were streaked on blood agar plates and incubated at 37℃ for 18-24 hours. The growth of normal flora observed after day 1 was considered as lysogens.Results:When specimens treated with lysin alone, lysogen formation was avoided and normal flora was controlled. Conclusions: Lysin may have no effect on the growth of lysogens. Sputum specimens treated with phagebiotics-lysin showed the growth of lysogens.

  9. 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.

  10. 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.

  11. 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.

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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

  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. PMID:27393678

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. The use of genomic signature distance between bacteriophages and their hosts displays evolutionary relationships and phage growth cycle determination

    Directory of Open Access Journals (Sweden)

    Regeard Christophe

    2010-07-01

    Full Text Available Abstract Background Bacteriophage classification is mainly based on morphological traits and genome characteristics combined with host information and in some cases on phage growth lifestyle. A lack of molecular tools can impede more precise studies on phylogenetic relationships or even a taxonomic classification. The use of methods to analyze genome sequences without the requirement for homology has allowed advances in classification. Results Here, we proposed to use genome sequence signature to characterize bacteriophages and to compare them to their host genome signature in order to obtain host-phage relationships and information on their lifestyle. We analyze the host-phage relationships in the four most representative groups of Caudoviridae, the dsDNA group of phages. We demonstrate that the use of phage genomic signature and its comparison with that of the host allows a grouping of phages and is also able to predict the host-phage relationships (lytic vs. temperate. Conclusions We can thus condense, in relatively simple figures, this phage information dispersed over many publications.

  10. Long amplicon (LA)-qPCR for the discrimination of infectious and noninfectious phix174 bacteriophages after UV inactivation.

    Science.gov (United States)

    Ho, Johannes; Seidel, Michael; Niessner, Reinhard; Eggers, Jutta; Tiehm, Andreas

    2016-10-15

    Waterborne viruses are increasingly being considered in risk assessment schemes. In general, virus detection by culture methods is time consuming. In contrast, detection by quantitative polymerase chain reaction (qPCR) is more rapid and therefore, more suitable for monitoring. At present, qPCR lacks the essential ability for discriminating between infectious and non-infectious viruses, thus limiting its applicability for monitoring disinfection processes. In this study, a method was developed to quantify UV inactivation by long amplicon (LA)-qPCR. Bacteriophage phiX174 was used as a surrogate for human pathogenic viruses. A qPCR protocol was developed with new sets of primers, resulting in amplicon lengths of 108, 250, 456, 568, 955, 1063, 1544, and 1764 nucleotides. The log reduction of gene copies increased with increasing amplicon length. Additional treatment with the intercalating dye, PMA, had no effect, indicating that the bacteriophage capsids were not damaged by low pressure UV irradiation. A qPCR of nearly the complete genome (approx. 5000 nucleotides) showed similar results to the plaque assay. The log reduction in qPCR correlates with [specific amplicon length x UV dose]. The normalized DNA effect constant can be applied to calculate phiX174 inactivation based on qPCR detection.

  11. Beyond the chromosome: the prevalence of unique extra-chromosomal bacteriophages with integrated virulence genes in pathogenic Staphylococcus aureus.

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    Bryan Utter

    Full Text Available In Staphylococcus aureus, the disease impact of chromosomally integrated prophages on virulence is well described. However, the existence of extra-chromosomal prophages, both plasmidial and episomal, remains obscure. Despite the recent explosion in bacterial and bacteriophage genomic sequencing, studies have failed to specifically focus on extra-chromosomal elements. We selectively enriched and sequenced extra-chromosomal DNA from S. aureus isolates using Roche-454 technology and uncovered evidence for the widespread distribution of multiple extra-chromosomal prophages (ExPΦs throughout both antibiotic-sensitive and -resistant strains. We completely sequenced one such element comprised of a 43.8 kbp, circular ExPΦ (designated ФBU01 from a vancomycin-intermediate S. aureus (VISA strain. Assembly and annotation of ФBU01 revealed a number of putative virulence determinants encoded within a bacteriophage immune evasion cluster (IEC. Our identification of several potential ExPΦs and mobile genetic elements (MGEs also revealed numerous putative virulence factors and antibiotic resistance genes. We describe here a previously unidentified level of genetic diversity of stealth extra-chromosomal elements in S. aureus, including phages with a larger presence outside the chromosome that likely play a prominent role in pathogenesis and strain diversity driven by horizontal gene transfer (HGT.

  12. Effects of Lactobacillus Probiotic, P22 Bacteriophage and Salmonella Typhimurium on the Heterophilic Burst Activity of Broiler Chickens

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    GA Marietto-Gonçalves

    2014-09-01

    Full Text Available Due to the constant evolution of industrial poultry production and the global emergence of bacterial resistance to antibiotics there has been an increasing interest in alternatives for the treatment of poultry salmonellosis, such as phage therapy and probiotics. The present study evaluated the effects of the oral administration of the bacteriophage P22 and of a probiotic, consisting of four Lactobacillus species, on the level of circulating heterophils containing a superoxide anion of one-day-old broilers challenged with Salmonella Typhimurium for seven days. It was concluded that the treatment with a probiotic with lactobacilli of broilers experimentally infected with Salmonella spp eliminates this pathogen by increasing the circulating levels of reactive heterophils. When chicks are treated with a probiotic and a bacteriophage, the agent is eliminated with no changes in circulating reactive heterophil counts. It is also concluded that the heterophils of day-old chicks are not capable of producing superoxide anion. However, this capacity is detected after 48 h of life, indicating that heterophils mature as birds age.

  13. Characterization of Vibrio cholerae bacteriophages isolated from the environmental waters of the Lake Victoria region of Kenya.

    Science.gov (United States)

    Maina, Alice Nyambura; Mwaura, Francis B; Oyugi, Julius; Goulding, David; Toribio, Ana L; Kariuki, Samuel

    2014-01-01

    Over the last decade, cholera outbreaks have become common in some parts of Kenya. The most recent cholera outbreak occurred in Coastal and Lake Victoria region during January 2009 and May 2010, where a total of 11,769 cases and 274 deaths were reported by the Ministry of Public Health and Sanitation. The objective of this study is to isolate Vibrio cholerae bacteriophages from the environmental waters of the Lake Victoria region of Kenya with potential for use as a biocontrol for cholera outbreaks. Water samples from wells, ponds, sewage effluent, boreholes, rivers, and lakes of the Lake Victoria region of Kenya were enriched for 48 h at 37 °C in broth containing a an environmental strain of V. cholerae. Bacteriophages were isolated from 5 out of the 42 environmental water samples taken. Isolated phages produced tiny, round, and clear plaques suggesting that these phages were lytic to V. cholerae. Transmission electron microscope examination revealed that all the nine phages belonged to the family Myoviridae, with typical icosahedral heads, long contractile tails, and fibers. Head had an average diameter of 88.3 nm and tail of length and width 84.9 and 16.1 nm, respectively. Vibriophages isolated from the Lake Victoria region of Kenya have been characterized and the isolated phages may have a potential to be used as antibacterial agents to control pathogenic V. cholerae bacteria in water reservoirs.

  14. 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.

  15. A comparison of Shiga-toxin 2 bacteriophage from classical enterohemorrhagic Escherichia coli serotypes and the German E. coli O104:H4 outbreak strain.

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    Chad R Laing

    Full Text Available Escherichia coli O104:H4 was associated with a severe foodborne disease outbreak originating in Germany in May 2011. More than 4000 illnesses and 50 deaths were reported. The outbreak strain was a typical enteroaggregative E. coli (EAEC that acquired an antibiotic resistance plasmid and a Shiga-toxin 2 (Stx2-encoding bacteriophage. Based on whole-genome phylogenies, the O104:H4 strain was most closely related to other EAEC strains; however, Stx2-bacteriophage are mobile, and do not necessarily share an evolutionary history with their bacterial host. In this study, we analyzed Stx2-bacteriophage from the E. coli O104:H4 outbreak isolates and compared them to all available Stx2-bacteriophage sequences. We also compared Stx2 production by an E. coli O104:H4 outbreak-associated isolate (ON-2011 to that of E. coli O157:H7 strains EDL933 and Sakai. Among the E. coli Stx2-phage sequences studied, that from O111:H- strain JB1-95 was most closely related phylogenetically to the Stx2-phage from the O104:H4 outbreak isolates. The phylogeny of most other Stx2-phage was largely concordant with their bacterial host genomes. Finally, O104:H4 strain ON-2011 produced less Stx2 than E. coli O157:H7 strains EDL933 and Sakai in culture; however, when mitomycin C was added, ON-2011 produced significantly more toxin than the E. coli O157:H7 strains. The Stx2-phage from the E. coli O104:H4 outbreak strain and the Stx2-phage from O111:H- strain JB1-95 likely share a common ancestor. Incongruence between the phylogenies of the Stx2-phage and their host genomes suggest the recent Stx2-phage acquisition by E. coli O104:H4. The increase in Stx2-production by ON-2011 following mitomycin C treatment may or may not be related to the high rates of hemolytic uremic syndrome associated with the German outbreak strain. Further studies are required to determine whether the elevated Stx2-production levels are due to bacteriophage or E. coli O104:H4 host related factors.

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

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    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

  17. 过氧乙酸对MS2噬菌体灭活效果的初步观察%PRELIMINARY OBSERVSATION ON INACTIVATION EFFICACY OF PEP ACETIC ACID TO BACTERIOPHAGE MS2

    Institute of Scientific and Technical Information of China (English)

    张杰; 陈昭斌; 许欣

    2012-01-01

    目的 研究过氧乙酸消毒剂对MS2噬菌体的灭活效果.方法 采用悬液定量灭活试验方法进行了实验室观察.结果 用浓度为200 mg/L的过氧乙酸消毒剂溶液作用60 min,对悬液内MS2噬菌体的平均灭活对数值为2.49.用浓度为1 200、800、500 mg/L的过氧乙酸溶液分别作用15、30和60 min,对悬液内MS2噬菌体的平均灭活对数值达到4.0以上.结论 在本试验条件下,较低浓度的过氧乙酸溶液对MS2噬菌体灭活效果较好.%Objective To study the inactivation effect of peracetic acid to bacteriophage MS2. Methods Suspension quantitative germicidal test was used to assess the inactivation efficacy of peracetic acid against bacteriophage MS2 in laboratory. Results The logarithm inactivation value (LIV) of bacteriophage MS2 was 2.49 by 200 mg/L peracetic acid within 60 min. When bacteriophage MS2 was disinfected by 1 200 mg/L, 800 mg/L and 500 mg/L peracetic acid within 15, 30 and 60 min respectively the LIV achieved the eligible disinfection level ( >4 .0). Conclusion Bacteriophage MS2 can be inactivated effectively by low concentration peracetic acid at room temperature.

  18. Current advance in the topological structure and function of holin encoded by bacteriophage Lambda-A review%λ噬茵体穿孔素(holin)蛋白触发裂菌的分子机制

    Institute of Scientific and Technical Information of China (English)

    史一博; 孙建和

    2012-01-01

    穿孔素-裂解酶二元裂解系统是双链DNA噬菌体普遍采用的裂菌模式,以λ噬菌体为例,系统地揭示了噬菌体穿孔素的结构与功能.λ噬菌体的S基因的特征是呈双起始基序( dual-start motif),编码穿孔素(holin) S105和抗穿孔素(antiholin) S107,通过二者不同水平的表达及相互作用,触发裂菌过程.作者综述了λ噬菌体穿孔素的膜拓扑结构和成孔机制的最新研究进展,并展望了穿孔素的研究热点和应用前景.%The holin-lysin two-step lysis system widely exists in double stranded DNA bacteriophages for the release of progeny bacteriophage from an infected bacterial cell at the final stage of phage infection. Lambda bacteriophage is a prototype for studying holin. The S gene in Lambda bacteriophage has a dual-start motif and encodes holin S105 and antiholin S107. Here, we reviewed the progress in topological structure of holin from Lambda bacteriophage and its formation of membrane lethal holes. We also discussed the potential of the holin in the control of bacterial infection.

  19. Utility of lytic bacteriophage in the treatment of multidrug-resistant Pseudomonas aeruginosa septicemia in mice

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    Vinodkumar C

    2008-07-01

    Full Text Available Drug resistance is the major cause of increase in morbidity and mortality in neonates. One thousand six hundred forty-seven suspected septicemic neonates were subjected for microbiological analysis over a period of 5 years. Forty-two P. aeruginosa were isolated and the antibiogram revealed that 28 P. aeruginosa were resistant to almost all the common drugs used (multidrug-resistant. The emergence of antibiotic-resistant bacterial strains is one of the most critical problems of modern medicine. As a result, a novel and most effective approaches for treating infection caused by multidrug-resistant bacteria are urgently required. In this context, one intriguing approach is to use bacteriophages (viruses that kill bacteria in the treatment of infection caused by drug-resistant bacteria. In the present study, the utility of lytic bacteriophages to rescue septicemic mice with multidrug-resistant (MDR P. aeruginosa infection was evaluated. MDR P. aeruginosa was used to induce septicemia in mice by intraperitoneal (i.p. injection of 10 7 CFU. The resulting bacteremia was fatal within 48 hrs. The phage strain used in this study had lytic activity against a wide range of clinical isolates of MDR P. aeruginosa. A single i.p. injection of 3 x 10 9 PFU of the phage strain, administered 45 min after the bacterial challenge, was sufficient to rescue 100% of the animals. Even when treatment was delayed to the point where all animals were moribund, approximately 50% of them were rescued by a single injection of this phage preparation. The ability of this phage to rescue septicemic mice was demonstrated to be due to the functional capabilities of the phage and not to a nonspecific immune effect. The rescue of septicemic mice could be affected only by phage strains able to grow in vitro on the bacterial host used to infect the animals and when such strains are heat-inactivated, they lose their ability to rescue the infected mice. Multidrug-resistant bacteria have

  20. Lactococcus bacteriophages isolated from whey and their effects on commercial lactic starters

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    Maria Raquel de Godoy Oriani

    2004-08-01

    Full Text Available The incidence of phages of lactic acid bacteria in milk industry and their effects on acidification ability of commercial lactic acid starters were studied. Cheese whey samples (33 samples were collected from 17 factories. A total of 16 bacteriophages were isolated (12 specific for Lactococcus lactis, 3 for L. diacetylactis and one capable of lysing both species. The results showed that 10% reduction in acidification tests was not good indication of phage in the sample. The majority of samples showed reduction higher than 10%, although only 65% were phage positive. The isolated phages were quite stable and showed no reduction in infectivity even after 20 daily replications. A pool of bacteriophages was prepared from isolates and inoculated in 12 commercial lactic starters. After 8 hours of incubation, only 2 showed reduced acidification. Bacterial strains isolated from commercial starters were tested regarding the phage resistance. Considerable difference in phage sensitivity was observed among different starters (BD, D, O and L. diacetylactis. Five bacteriophages showed no infectivity on any isolates but one was infective for most of isolates.Para ampliar conhecimentos sobre a incidência de bacteriófagos de bactérias lácticas na indústria de leite do Estado de São Paulo e a sua influência sobre a capacidade acidificante de fermentos lácticos disponíveis em nosso mercado, o presente trabalho foi conduzido com o intuito de esclarecer a real situação dos laticínios no Estado. Foram coletadas 33 amostras de soro de queijo em 17 laticínios. Foram isolados 16 bacteriófagos, 12 específicos para Lactococcus lactis, 3 para L. diacetylactis e um capaz de lisar ambos os microrganismos. Os experimentos mostraram que, uma diminuição de 10% na acidez em presença de soro suspeito, ao contrário do estabelecido na literatura, não reflete a veracidade da presença de bacteriófagos na amostra, uma vez que a maioria apresentou redução acima

  1. 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

  2. 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...

  3. 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.

  4. 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)

  5. Quantitative models of in vitro bacteriophage-host dynamics and their application to phage therapy.

    Directory of Open Access Journals (Sweden)

    Benjamin J Cairns

    2009-01-01

    Full Text Available Phage therapy is the use of bacteriophages as antimicrobial agents for the control of pathogenic and other problem bacteria. It has previously been argued that successful application of phage therapy requires a good understanding of the non-linear kinetics of phage-bacteria interactions. Here we combine experimental and modelling approaches to make a detailed examination of such kinetics for the important food-borne pathogen Campylobacter jejuni and a suitable virulent phage in an in vitro system. Phage-insensitive populations of C. jejuni arise readily, and as far as we are aware this is the first phage therapy study to test, against in vitro data, models for phage-bacteria interactions incorporating phage-insensitive or resistant bacteria. We find that even an apparently simplistic model fits the data surprisingly well, and we confirm that the so-called inundation and proliferation thresholds are likely to be of considerable practical importance to phage therapy. We fit the model to time series data in order to estimate thresholds and rate constants directly. A comparison of the fit for each culture reveals density-dependent features of phage infectivity that are worthy of further investigation. Our results illustrate how insight from empirical studies can be greatly enhanced by the use of kinetic models: such combined studies of in vitro systems are likely to be an essential precursor to building a meaningful picture of the kinetic properties of in vivo phage therapy.

  6. Insights into new bacteriophages of Lactococcus garvieae belonging to the family Podoviridae.

    Science.gov (United States)

    Ghasemi, Seyed Mahdi; Bouzari, Majid; Shaykh Baygloo, Nima; Chang, Hyo-Ihl

    2014-11-01

    Lactococcus garvieae is an emerging pathogen responsible for lactococcosis, a serious disease in trout aquaculture. The identification of new bacteriophages against L. garvieae strains may be an effective way to fight this disease and to study the pathogen's biology. Three L. garvieae phages, termed WP-1, WWP-2 and SP-2, were isolated from different environments, and their morphological features, genome restriction profiles and structural protein patterns were studied. Random cloning of HindIII-cut fragments was performed, and the fragments were partially sequenced for each phage. Although slight differences were observed by transmission electron microscopy, all of the phages had hexagonal heads and short non-contractile tails and were classified as members of the family Podoviridae. Restriction digestion analysis of the nucleic acids of the different phages revealed that the HindIII and AseI digests produced similar DNA fragment patterns. Additionally, SDS-PAGE analysis indicated that the isolated phages have similar structural proteins. The sequence BLAST results did not show any significant similarity with other previously identified phages. To the best of our knowledge, this study provides the first molecular characterization of L. garvieae phages.

  7. Effect of bacteriophage application on Campylobacter jejuni loads in commercial broiler flocks.

    Science.gov (United States)

    Kittler, Sophie; Fischer, Samuel; Abdulmawjood, Amir; Glünder, Gerhard; Klein, Günter

    2013-12-01

    Campylobacteriosis is the most frequent food-borne human enteritis. The major source for infection with Campylobacter spp. is broiler meat. Risk assessments consider the reduction of Campylobacter in primary production to be most beneficial for human health. The aim of this study was to test the efficacy of a bacteriophage application under commercial conditions which had proved to be effective in previous noncommercial studies under controlled experimental conditions. A phage cocktail for Campylobacter reduction was tested on three commercial broiler farms each with a control and an experimental group. Colonization of Campylobacter was confirmed prior to phage application in fecal samples. Subsequently, a phage cocktail was applied via drinking water in the experimental group (log10 5.8 to 7.5 PFU/bird). One day after phage application, Campylobacter counts of one experimental group were reduced under the detection limit (log10 3.2 CFU/g cecal content compared to the control was still detected (P=0.0011). No significant reduction was observed in the experimental groups of the other trials. However, a significant drop in cecal Campylobacter counts occurred in a phage-contaminated control. These results suggest that maximum reduction of Campylobacter at the slaughterhouse might be achieved by phage application 1 to 4 days prior to slaughter.

  8. Aggregation Rates of Sediments (Montmorillonite, Kaolinite, Illite and Goethite) with the Enveloped Φ6 Bacteriophage

    Science.gov (United States)

    Katz, A.; Block, K. A.; Peña, S.; Alimova, A.; Gottlieb, P.

    2015-12-01

    The interaction between sediments and viruses has been studied extensively from the prospective of virus survivability and infectivity. However, the role of soil organisms, including viruses in C and N sequestration in soil has not been studied as extensively. Φ6, a member of the cystoviridae family, is a bacteriophage that infects Pseudomonas syringae, a common plant pathogen known to readily form biofilms.The small mineral fraction (pH to slightly acidic pH, Φ6 is slightly negatively charged; montmorillonite and illite are negatively charged; and kaolinite and goethite are positively charged. In isolation, neither Φ6 nor the sediments aggregated in the modified buffer. However, in mixtures, Φ6 and montmorillonite, and Φ6 and illite, exhibited increases in turbidity, indicating heteroaggregation. Neither Φ6 and kaolinite, nor Φ6 and goethite, exhibited increased turbidity upon mixing indicating little or no aggregation. These results suggest that the interaction of the virus with the sediments is governed by hydrophobic rather than electrostatic forces. Heteroaggregation rates were calculated from the time rate of change of the turbidity.

  9. [Polyvalence of bacteriophages isolated from fruit trees, affected by bacterial fire blight].

    Science.gov (United States)

    Tovkach, F I; Moroz, S N; Korol', N A; Faĭdiuk, Iu V; Kushkina, A I

    2013-01-01

    Phage populations appearing as a result of a pathogenic process caused by Erwinia amylovora have been discovered and described. They accompany bacterial fire blight development in the process of quince, pear and apple trees vegetation in Zakarpattya region of Ukraine. Phage isolates of the affected pear and quince include polyvalent virulent phages able to develop on bacterial strains associated with plants--E. amylovora. E. "horticola" and Pantoea agglomerans. E. amylovora isolated from the plant tissues affected by the fire blight and detected at the same time as phages proved to be resistant to the viral infection. It is hard to explain now this characteristic however it was noticed that resistance to phages can change drastically in case of dissociation, lysogenization and mutagenesis of erwinia in laboratory conditions. Phage population study shows that they are heterogeneous and can obviously include not only polyvalent but also specific viruses. Further studies of biology and molecular genetics of pure lines of isolated phages will help to get closer to understanding the place and role of bacteriophages in the complicated network of relations between bacterial pathogens and plants.

  10. Global analysis of host response to induction of a latent bacteriophage

    Directory of Open Access Journals (Sweden)

    Keasling Jay D

    2007-08-01

    Full Text Available Abstract Background The transition from viral latency to lytic growth involves complex interactions among host and viral factors, and the extent to which host physiology is buffered from the virus during induction of lysis is not known. A reasonable hypothesis is that the virus should be evolutionarily selected to ensure host health throughout induction to minimize its chance of reproductive failure. To address this question, we collected transcriptional profiles of Escherichia coli and bacteriophage lambda throughout lysogenic induction by UV light. Results We observed a temporally coordinated program of phage gene expression, with distinct early, middle and late transcriptional classes. Our study confirmed known host-phage interactions of induction of the heat shock regulon, escape replication, and suppression of genes involved in cell division and initiation of replication. We identified 728 E. coli genes responsive to prophage induction, which included pleiotropic stress response pathways, the Arc and Cpx regulons, and global regulators crp and lrp. Several hundred genes involved in central metabolism, energy metabolism, translation and transport were down-regulated late in induction. Though statistically significant, most of the changes in these genes were mild, with only 140 genes showing greater than two-fold change. Conclusion Overall, we observe that prophage induction has a surprisingly low impact on host physiology. This study provides the first global dynamic picture of how host processes respond to lambda phage induction.

  11. Assembly and dynamics of the bacteriophage T4 homologous recombination machinery

    Directory of Open Access Journals (Sweden)

    Morrical Scott W

    2010-12-01

    Full Text Available Abstract Homologous recombination (HR, a process involving the physical exchange of strands between homologous or nearly homologous DNA molecules, is critical for maintaining the genetic diversity and genome stability of species. Bacteriophage T4 is one of the classic systems for studies of homologous recombination. T4 uses HR for high-frequency genetic exchanges, for homology-directed DNA repair (HDR processes including DNA double-strand break repair, and for the initiation of DNA replication (RDR. T4 recombination proteins are expressed at high levels during T4 infection in E. coli, and share strong sequence, structural, and/or functional conservation with their counterparts in cellular organisms. Biochemical studies of T4 recombination have provided key insights on DNA strand exchange mechanisms, on the structure and function of recombination proteins, and on the coordination of recombination and DNA synthesis activities during RDR and HDR. Recent years have seen the development of detailed biochemical models for the assembly and dynamics of presynaptic filaments in the T4 recombination system, for the atomic structure of T4 UvsX recombinase, and for the roles of DNA helicases in T4 recombination. The goal of this chapter is to review these recent advances and their implications for HR and HDR mechanisms in all organisms.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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).

  19. 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.

  20. 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.