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Sample records for infrared fluorescnce-based bacteriophage

  1. Campylobacter bacteriophages and bacteriophage therapy.

    PubMed

    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.

  2. Lytic bacteriophages

    PubMed Central

    Sharma, Manan

    2013-01-01

    Foodborne illnesses resulting from the consumption of produce commodities contaminated with enteric pathogens continue to be a significant public health issue. Lytic bacteriophages may provide an effective and natural intervention to reduce bacterial pathogens on fresh and fresh-cut produce commodities. The use of multi-phage cocktails specific for a single pathogen has been most frequently assessed on produce commodities to minimize the development of bacteriophage insensitive mutants (BIM) in target pathogen populations. Regulatory approval for the use of several lytic phage products specific for bacterial pathogens such as Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes in foods and on food processing surfaces has been granted by various agencies in the US and other countries, possibly allowing for the more widespread use of bacteriophages in the decontamination of fresh and minimally processed produce. Research studies have shown lytic bacteriophages specific for E. coli O157:H7, Salmonella spp. and Listeria monocytogenes have been effective in reducing pathogen populations on leafy greens, sprouts and tomatoes. PMID:24228223

  3. Chlamydia bacteriophages.

    PubMed

    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

  4. Chlamydia bacteriophages.

    PubMed

    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.

  5. Bacteriophages Infecting Propionibacterium acnes

    PubMed Central

    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. PMID:23691509

  6. Bacteriophages infecting Propionibacterium acnes.

    PubMed

    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.

  7. Bacteriophages and cancer.

    PubMed

    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.

  8. Bacteriophages and Biofilms

    PubMed Central

    Harper, David R.; Parracho, Helena M. R. T.; Walker, James; Sharp, Richard; Hughes, Gavin; Werthén, Maria; Lehman, Susan; Morales, Sandra

    2014-01-01

    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.

  9. Hyperexpansion of RNA Bacteriophage Diversity.

    PubMed

    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. PMID:27010970

  10. Hyperexpansion of RNA Bacteriophage Diversity

    PubMed Central

    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

  11. Hyperexpansion of RNA Bacteriophage Diversity.

    PubMed

    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.

  12. Infrared

    NASA Astrophysics Data System (ADS)

    Vollmer, M.

    2013-11-01

    'Infrared' is a very wide field in physics and the natural sciences which has evolved enormously in recent decades. It all started in 1800 with Friedrich Wilhelm Herschel's discovery of infrared (IR) radiation within the spectrum of the Sun. Thereafter a few important milestones towards widespread use of IR were the quantitative description of the laws of blackbody radiation by Max Planck in 1900; the application of quantum mechanics to understand the rotational-vibrational spectra of molecules starting in the first half of the 20th century; and the revolution in source and detector technologies due to micro-technological breakthroughs towards the end of the 20th century. This has led to much high-quality and sophisticated equipment in terms of detectors, sources and instruments in the IR spectral range, with a multitude of different applications in science and technology. This special issue tries to focus on a few aspects of the astonishing variety of different disciplines, techniques and applications concerning the general topic of infrared radiation. Part of the content is based upon an interdisciplinary international conference on the topic held in 2012 in Bad Honnef, Germany. It is hoped that the information provided here may be useful for teaching the general topic of electromagnetic radiation in the IR spectral range in advanced university courses for postgraduate students. In the most general terms, the infrared spectral range is defined to extend from wavelengths of 780 nm (upper range of the VIS spectral range) up to wavelengths of 1 mm (lower end of the microwave range). Various definitions of near, middle and far infrared or thermal infrared, and lately terahertz frequencies, are used, which all fall in this range. These special definitions often depend on the scientific field of research. Unfortunately, many of these fields seem to have developed independently from neighbouring disciplines, although they deal with very similar topics in respect of the

  13. [Bacteriophages as antibacterial agents].

    PubMed

    Shasha, Shaul M; Sharon, Nehama; Inbar, Michael

    2004-02-01

    Bacteriophages are viruses that only infect bacteria. They have played an important role in the development of molecular biology and have been used as anti-bacterial agents. Since their independent discovery by Twort and d'Herelle, they have been extensively used to prevent and treat bacterial infections, mainly in Eastern Europe and the former Soviet Union. In western countries this method has been sporadically employed on humans and domesticated animals. However, the discovery and widespread use of antibiotics, coupled with doubts about the efficacy of phage therapy, led to an eclipse in the use of phage in medicine. The emergence of antibiotic resistant bacteria, especially strains that are multiply resistant, has resulted in a renewed interest in alternatives to conventional drugs. One of the possible replacements for antibiotics is the use of bacteriophages as antimicrobial agents. This brief review aims to describe the history of bacteriophage and early clinical studies on their use in bacterial disease prophylaxis and therapy, and discuss the advantages and disadvantages of bacteriophage in this regard.

  14. BACTERIOPHAGE THERAPY AND CAMPYLOBACTER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The book chapter reports efforts to exploit Campylobacter-specific bacteriophages to reduce the numbers of Campylobacter jejuni and C. coli colonizing poultry and contaminating poultry meat products. Controlling campylobacters in poultry represents one of the greatest challenges to the agriculture a...

  15. Chlamydial plasmids and bacteriophages.

    PubMed

    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. Bacteriophages of Clostridium perfringens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The specific aims of the book chapter are to: (1) Briefly review the nomenclature of bacteriophages and how these agents are classified. (2) Discuss the problems associated with addition/removal of antibiotics in commercial animal feeds. (3) Provide a brief overview of Clostridium perfringens biolog...

  17. Infrared

    NASA Astrophysics Data System (ADS)

    Vollmer, M.

    2013-11-01

    'Infrared' is a very wide field in physics and the natural sciences which has evolved enormously in recent decades. It all started in 1800 with Friedrich Wilhelm Herschel's discovery of infrared (IR) radiation within the spectrum of the Sun. Thereafter a few important milestones towards widespread use of IR were the quantitative description of the laws of blackbody radiation by Max Planck in 1900; the application of quantum mechanics to understand the rotational-vibrational spectra of molecules starting in the first half of the 20th century; and the revolution in source and detector technologies due to micro-technological breakthroughs towards the end of the 20th century. This has led to much high-quality and sophisticated equipment in terms of detectors, sources and instruments in the IR spectral range, with a multitude of different applications in science and technology. This special issue tries to focus on a few aspects of the astonishing variety of different disciplines, techniques and applications concerning the general topic of infrared radiation. Part of the content is based upon an interdisciplinary international conference on the topic held in 2012 in Bad Honnef, Germany. It is hoped that the information provided here may be useful for teaching the general topic of electromagnetic radiation in the IR spectral range in advanced university courses for postgraduate students. In the most general terms, the infrared spectral range is defined to extend from wavelengths of 780 nm (upper range of the VIS spectral range) up to wavelengths of 1 mm (lower end of the microwave range). Various definitions of near, middle and far infrared or thermal infrared, and lately terahertz frequencies, are used, which all fall in this range. These special definitions often depend on the scientific field of research. Unfortunately, many of these fields seem to have developed independently from neighbouring disciplines, although they deal with very similar topics in respect of the

  18. Cytoplasmic bacteriophage display system

    DOEpatents

    Studier, F. William; Rosenberg, Alan H.

    1998-06-16

    Disclosed are display vectors comprising DNA encoding a portion of a structural protein from a cytoplasmic bacteriophage, joined covalently to a protein or peptide of interest. Exemplified are display vectors wherein the structural protein is the T7 bacteriophage capsid protein. More specifically, in the exemplified display vectors the C-terminal amino acid residue of the portion of the capsid protein is joined to the N-terminal residue of the protein or peptide of interest. The portion of the T7 capsid protein exemplified comprises an N-terminal portion corresponding to form 10B of the T7 capsid protein. The display vectors are useful for high copy number display or lower copy number display (with larger fusion). Compositions of the type described herein are useful in connection with methods for producing a virus displaying a protein or peptide of interest.

  19. Cytoplasmic bacteriophage display system

    DOEpatents

    Studier, F.W.; Rosenberg, A.H.

    1998-06-16

    Disclosed are display vectors comprising DNA encoding a portion of a structural protein from a cytoplasmic bacteriophage, joined covalently to a protein or peptide of interest. Exemplified are display vectors wherein the structural protein is the T7 bacteriophage capsid protein. More specifically, in the exemplified display vectors the C-terminal amino acid residue of the portion of the capsid protein is joined to the N-terminal residue of the protein or peptide of interest. The portion of the T7 capsid protein exemplified comprises an N-terminal portion corresponding to form 10B of the T7 capsid protein. The display vectors are useful for high copy number display or lower copy number display (with larger fusion). Compositions of the type described herein are useful in connection with methods for producing a virus displaying a protein or peptide of interest. 1 fig.

  20. [Possibilities of bacteriophage therapy].

    PubMed

    Skurnik, Mikael; Kiljunen, Saija

    2016-01-01

    Antibiotic resistance of bacterial pathogens has increased, and new therapies are urgently needed. Bacteriophages (phages), viruses infecting and killing bacteria, are the most abundant organisms on earth. In nature there are several specific phages for every bacterium, controlling bacterial numbers and maintaining ecological balance. Phage therapy, i.e., treating bacterial infections with phages, offers an alternative complementary to antibiotics as phages infect and kill also multi-resistant bacteria. Phages possess narrow host specificity, each phage infecting only a few bacterial species or strains. Thereby phages do not harm the normal microbiota as antibiotics do. We aim to begin clinical trials of phage therapy in Finland. PMID:27244930

  1. Bacteriophages of methanotrophic bacteria

    SciTech Connect

    Tyutikow, F.M.; 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.

  2. Genetically modified bacteriophages.

    PubMed

    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.

  3. Genetically modified bacteriophages.

    PubMed

    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

  4. Lysogenic bacteriophage isolated from acidophilium

    SciTech Connect

    Ward, Thomas W.; Bruhn, Debby F.; Bulmer, Deborah K.

    1992-01-01

    A bacteriophage identified as .phi.Ac1 capable of infecting acidophilic heterotropic bacteria (such as Acidiphilium sp.) and processes for genetically engineering acidophilic bacteria for biomining or sulfur removal from coal are disclosed. The bacteriophage is capable of growth in cells existing at pH at or below 3.0. Lytic forms of the phage introduced into areas experiencing acid drainage kill the bacteria causing such drainage. Lysogenic forms of the phase having genes for selective removal of metallic or nonmetallic elements can be introduced into acidophilic bacteria to effect removal of the desired element form ore or coal.

  5. Mechanics of bacteriophage maturation.

    PubMed

    Roos, Wouter H; Gertsman, Ilya; May, Eric R; Brooks, Charles L; Johnson, John E; Wuite, Gijs J L

    2012-02-14

    Capsid maturation with large-scale subunit reorganization occurs in virtually all viruses that use a motor to package nucleic acid into preformed particles. A variety of ensemble studies indicate that the particles gain greater stability during this process, however, it is unknown which material properties of the fragile procapsids change. Using Atomic Force Microscopy-based nano-indentation, we study the development of the mechanical properties during maturation of bacteriophage HK97, a λ-like phage of which the maturation-induced morphological changes are well described. We show that mechanical stabilization and strengthening occurs in three independent ways: (i) an increase of the Young's modulus, (ii) a strong rise of the capsid's ultimate strength, and (iii) a growth of the resistance against material fatigue. The Young's modulus of immature and mature capsids, as determined from thin shell theory, fit with the values calculated using a new multiscale simulation approach. This multiscale calculation shows that the increase in Young's modulus isn't dependent on the crosslinking between capsomers. In contrast, the ultimate strength of the capsids does increase even when a limited number of cross-links are formed while full crosslinking appears to protect the shell against material fatigue. Compared to phage λ, the covalent crosslinking at the icosahedral and quasi threefold axes of HK97 yields a mechanically more robust particle than the addition of the gpD protein during maturation of phage λ. These results corroborate the expected increase in capsid stability and strength during maturation, however in an unexpected intricate way, underlining the complex structure of these self-assembling nanocontainers.

  6. Bacteriophage therapy in animal production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Concerns over the consequences of bacterial resistance to antibiotics with the use of antibiotics in animal production have led to an increase in research on alternatives to antibiotics. Bacteriophages kill bacteria, are natural, safe, plentiful, self replicating, self limiting, can be used to spec...

  7. Bacteriophage endolysins as novel antimicrobials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  8. Bacteriophages: back to the future

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    PubMed

    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.

  10. Bacteriophage Procurement for Therapeutic Purposes.

    PubMed

    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

  11. Bacteriophage Procurement for Therapeutic Purposes

    PubMed Central

    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

  12. Recombinant bacteriophage lysins as antibacterials

    PubMed Central

    Fenton, Mark; Ross, Paul; McAuliffe, Olivia; O'Mahony, Jim

    2010-01-01

    With the increasing worldwide prevalence of antibiotic resistant bacteria, bacteriophage endolysins (lysins) represent a very promising novel alternative class of antibacterial in the fight against infectious disease. Lysins are phage-encoded peptidoglycan hydrolases which, when applied exogenously (as purified recombinant proteins) to Gram-positive bacteria, bring about rapid lysis and death of the bacterial cell. A number of studies have recently demonstrated the strong potential of these enzymes in human and veterinary medicine to control and treat pathogens on mucosal surfaces and in systemic infections. They also have potential in diagnostics and detection, bio-defence, elimination of food pathogens and control of phytopathogens. This review discusses the extensive research on recombinant bacteriophage lysins in the context of antibacterials, and looks forward to future development and potential. PMID:21327123

  13. Bacteriophage biocontrol of foodborne pathogens.

    PubMed

    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

  14. Bacteriophage Transduction in Staphylococcus epidermidis

    PubMed Central

    Olson, Michael E.; Horswill, Alexander R.

    2016-01-01

    The genetic manipulation of Staphylococcus epidermidis for molecular experimentation has long been an area of difficulty. Many of the traditional laboratory techniques for strain construction are laborious and hampered by poor efficiency. The ability to move chromosomal genetic markers and plasmids using bacteriophage transduction has greatly increased the speed and ease of S. epidermidis studies. These molecular genetic advances have advanced the S. epidermidis research field beyond a select few genetically tractable strains and facilitated investigations of clinically relevant isolates. PMID:24222465

  15. Bacteriophage Transduction in Staphylococcus aureus.

    PubMed

    Olson, Michael E

    2016-01-01

    The genetic manipulation of Staphylococcus aureus for molecular experimentation is a valuable tool for assessing gene function and virulence. Genetic variability between strains coupled with difficult laboratory techniques for strain construction is a frequent roadblock in S. aureus research. Bacteriophage transduction greatly increases the speed and ease of S. aureus studies by allowing movement of chromosomal markers and plasmids between strains. This technique enables the S. aureus research community to focus investigations on clinically relevant isolates.

  16. Programming Bacteriophages by Swapping Their Specificity Determinants.

    PubMed

    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.

  17. Use of Bacteriophages to control bacterial pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  18. Nanoscale bacteriophage biosensors beyond phage display.

    PubMed

    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.

  19. Nanoscale bacteriophage biosensors beyond phage display

    PubMed Central

    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. PMID:24143096

  20. [Spontaneous bacteriophage induction in Bacillus thuringiensis].

    PubMed

    Besaeva, S G; Mikhaĭlov, A A; Petrova, T M; Tur, A I; Bystrova, E V

    1987-01-01

    The production of temperate bacteriophages was studied in the process of batch cultivation of three Bacillus thuringiensis lysogenic strains. Phage titres were determined using an indicator culture (IPM-1148). The growth of bacteriophages was induced when thermoactivated spores germinated. Some cells (1.10(-3)-2.10(-3)) underwent lysis without their division. The subsequent lytic cycles occurred in the actively growing culture. Phage titres ceased to rise before the exponential growth phase was over.

  1. Arthrobacter globiformis and its bacteriophage in soil

    NASA Technical Reports Server (NTRS)

    Casida, L. E., Jr.; Liu, K.-C.

    1974-01-01

    An attempt was made to correlate bacteriophages for Arthrobacter globiformis with soils containing that bacterium. The phages were not detected unless the soil was nutritionally amended (with glucose or sucrose) and incubated for several days. Phage was continuously produced after amendment without the addition of host Arthrobacter. These results indicate that the bacteriophage is present in a masked state and that the bacteria are present in an insensitive form which becomes sensitive after addition of nutrient.

  2. Taking Bacteriophage Therapy Seriously: A Moral Argument

    PubMed Central

    Verbeken, Gilbert; Huys, Isabelle; Jennes, Serge; Chanishvili, Nina; Górski, Andrzej; De Vos, Daniel

    2014-01-01

    The excessive and improper use of antibiotics has led to an increasing incidence of bacterial resistance. In Europe the yearly number of infections caused by multidrug resistant bacteria is more than 400.000, each year resulting in 25.000 attributable deaths. Few new antibiotics are in the pipeline of the pharmaceutical industry. Early in the 20th century, bacteriophages were described as entities that can control bacterial populations. Although bacteriophage therapy was developed and practiced in Europe and the former Soviet republics, the use of bacteriophages in clinical setting was neglected in Western Europe since the introduction of traditional antibiotics. Given the worldwide antibiotic crisis there is now a growing interest in making bacteriophage therapy available for use in modern western medicine. Despite the growing interest, access to bacteriophage therapy remains highly problematic. In this paper, we argue that the current state of affairs is morally unacceptable and that all stakeholders (pharmaceutical industry, competent authorities, lawmakers, regulators, and politicians) have the moral duty and the shared responsibility towards making bacteriophage therapy urgently available for all patients in need. PMID:24868534

  3. Characterization and purification of bacteriophages using chromatofocusing.

    PubMed

    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.

  4. Pathogen detection using engineered bacteriophages.

    PubMed

    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.

  5. Bacteriophage endolysins as novel antimicrobials

    PubMed Central

    Schmelcher, Mathias; Donovan, David M; Loessner, Martin J

    2013-01-01

    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 access the peptidoglycan and destroy these organisms when applied externally, making them interesting antimicrobial candidates, particularly in light of increasing bacterial drug resistance. This article reviews the modular structure of these enzymes, in which cell wall binding and catalytic functions are separated, as well as their mechanism of action, lytic activity and potential as antimicrobials. It particularly focuses on molecular engineering as a means of optimizing endolysins for specific applications, highlights new developments that may render these proteins active against Gram-negative and intracellular pathogens and summarizes the most recent applications of endolysins in the fields of medicine, food safety, agriculture and biotechnology. PMID:23030422

  6. Host receptors for bacteriophage adsorption.

    PubMed

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

    2016-02-01

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

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

    PubMed

    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

    2016-01-01

    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. PMID:27231352

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

    PubMed Central

    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

    2016-01-01

    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. PMID:27231352

  9. Differential Bacteriophage Mortality on Exposure to Copper ▿

    PubMed Central

    Li, Jinyu; Dennehy, John J.

    2011-01-01

    Many studies report that copper can be used to control microbial growth, including that of viruses. We determined the rates of copper-mediated inactivation for a wide range of bacteriophages. We used two methods to test the effect of copper on bacteriophage survival. One method involved placing small volumes of bacteriophage lysate on copper and stainless steel coupons. Following exposure, metal coupons were rinsed with lysogeny broth, and the resulting fluid was serially diluted and plated on agar with the corresponding bacterial host. The second method involved adding copper sulfate (CuSO4) to bacteriophage lysates to a final concentration of 5 mM. Aliquots were removed from the mixture, serially diluted, and plated with the appropriate bacterial host. Significant mortality was observed among the double-stranded RNA (dsRNA) bacteriophages Φ6 and Φ8, the single-stranded RNA (ssRNA) bacteriophage PP7, the ssDNA bacteriophage ΦX174, and the dsDNA bacteriophage PM2. However, the dsDNA bacteriophages PRD1, T4, and λ were relatively unaffected by copper. Interestingly, lipid-containing bacteriophages were most susceptible to copper toxicity. In addition, in the first experimental method, the pattern of bacteriophage Φ6 survival over time showed a plateau in mortality after lysates dried out. This finding suggests that copper's effect on bacteriophage is mediated by the presence of water. PMID:21841029

  10. Bacteriophage-Based Pathogen Detection

    NASA Astrophysics Data System (ADS)

    Ripp, Steven

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

  11. Bacteriophage lysis: mechanism and regulation.

    PubMed

    Young, R

    1992-09-01

    Bacteriophage lysis involves at least two fundamentally different strategies. Most phages elaborate at least two proteins, one of which is a murein hydrolase, or lysin, and the other is a membrane protein, which is given the designation holin in this review. The function of the holin is to create a lesion in the cytoplasmic membrane through which the murein hydrolase passes to gain access to the murein layer. This is necessary because phage-encoded lysins never have secretory signal sequences and are thus incapable of unassisted escape from the cytoplasm. The holins, whose prototype is the lambda S protein, share a common organization in terms of the arrangement of charged and hydrophobic residues, and they may all contain at least two transmembrane helical domains. The available evidence suggests that holins oligomerize to form nonspecific holes and that this hole-forming step is the regulated step in phage lysis. The correct scheduling of the lysis event is as much an essential feature of holin function as is the hole formation itself. In the second strategy of lysis, used by the small single-stranded DNA phage phi X174 and the single-stranded RNA phage MS2, no murein hydrolase activity is synthesized. Instead, there is a single species of small membrane protein, unlike the holins in primary structure, which somehow causes disruption of the envelope. These lysis proteins function by activation of cellular autolysins. A host locus is required for the lytic function of the phi X174 lysis gene E.

  12. Photodynamic Inactivation of Mammalian Viruses and Bacteriophages

    PubMed Central

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

    2012-01-01

    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. PMID:22852040

  13. Photodynamic inactivation of mammalian viruses and bacteriophages.

    PubMed

    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.

  14. Antiviral effect of cationic compounds on bacteriophages

    PubMed Central

    Ly-Chatain, Mai H.; Moussaoui, Saliha; Vera, Annabelle; Rigobello, Véronique; Demarigny, Yann

    2013-01-01

    The antiviral activity of several cationic compounds – cetyltrimethylammonium bromide (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 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. PMID:23487495

  15. Bacteriophages as Potential Treatment for Urinary Tract Infections

    PubMed Central

    Sybesma, Wilbert; Zbinden, Reinhard; Chanishvili, Nino; Kutateladze, Mzia; Chkhotua, Archil; Ujmajuridze, Aleksandre; Mehnert, Ulrich; Kessler, Thomas M.

    2016-01-01

    Background: Urinary tract infections (UTIs) are among the most prevalent microbial diseases and their financial burden on society is substantial. The continuing increase of antibiotic resistance worldwide is alarming so that well-tolerated, highly effective therapeutic alternatives are urgently needed. Objective: To investigate the effect of bacteriophages on Escherichia coli and Klebsiella pneumoniae strains isolated from the urine of patients suffering from UTIs. Material and methods: Forty-one E. coli and 9 K. pneumoniae strains, isolated from the urine of patients suffering from UTIs, were tested in vitro for their susceptibility toward bacteriophages. The bacteriophages originated from either commercially available bacteriophage cocktails registered in Georgia or from the bacteriophage collection of the George Eliava Institute of Bacteriophage, Microbiology and Virology. In vitro screening of bacterial strains was performed by use of the spot-test method. The experiments were implemented three times by different groups of scientists. Results: The lytic activity of the commercial bacteriophage cocktails on the 41 E. coli strains varied between 66% (Pyo bacteriophage) and 93% (Enko bacteriophage). After bacteriophage adaptation of the Pyo bacteriophage cocktail, its lytic activity was increased from 66 to 93% and only one E. coli strain remained resistant. One bacteriophage of the Eliava collection could lyse all 9 K. pneumoniae strains. Conclusions: Based on the high lytic activity and the potential of resistance optimization by direct adaption of bacteriophages as reported in this study, and in view of the continuing increase of antibiotic resistance worldwide, bacteriophage therapy is a promising treatment option for UTIs highly warranting randomized controlled trials. PMID:27148173

  16. Genetic evolution of bacteriophage. I. Hybrids between unrelated bacteriophages P22 and Fels 2.

    PubMed

    Yamamoto, N

    1969-01-01

    A new bacteriophage species, designated F22, was isolated from phage P22 stocks grown on Salmonella typhimurium Q1 lysogenic for Fels 2 at a frequency of less than 10(-11). P22 has a very short tail with a hexagonal base plate and six spikes. Phage Fels 2 is morphologically similar to E. coli T-even phages, having a long tail with a contractile sheath and carrying no genetic region related to P22. Phage F22 is morphologically and serologically indistinguishable from Fels 2, but carries the c(c(1), c(2), and c(3)) markers of P22. The color markers h(21), g, and m(3) of P22 do not appear in F22. Thus, F22 is evidently a recombinant between the unrelated bacteriophages P22 and Fels 2. The recombination between unrelated bacteriophages could play an important role in the evolution of bacteriophages.

  17. Bacteriophage protein-protein interactions.

    PubMed

    Häuser, Roman; Blasche, Sonja; Dokland, Terje; Haggård-Ljungquist, Elisabeth; von Brunn, Albrecht; Salas, Margarita; Casjens, Sherwood; Molineux, Ian; Uetz, Peter

    2012-01-01

    Bacteriophages T7, λ, P22, and P2/P4 (from Escherichia coli), as well as ϕ29 (from Bacillus subtilis), are among the best-studied bacterial viruses. This chapter summarizes published protein interaction data of intraviral protein interactions, as well as known phage-host protein interactions of these phages retrieved from the literature. We also review the published results of comprehensive protein interaction analyses of Pneumococcus phages Dp-1 and Cp-1, as well as coliphages λ and T7. For example, the ≈55 proteins encoded by the T7 genome are connected by ≈43 interactions with another ≈15 between the phage and its host. The chapter compiles published interactions for the well-studied phages λ (33 intra-phage/22 phage-host), P22 (38/9), P2/P4 (14/3), and ϕ29 (20/2). We discuss whether different interaction patterns reflect different phage lifestyles or whether they may be artifacts of sampling. Phages that infect the same host can interact with different host target proteins, as exemplified by E. coli phage λ and T7. Despite decades of intensive investigation, only a fraction of these phage interactomes are known. Technical limitations and a lack of depth in many studies explain the gaps in our knowledge. Strategies to complete current interactome maps are described. Although limited space precludes detailed overviews of phage molecular biology, this compilation will allow future studies to put interaction data into the context of phage biology. PMID:22748812

  18. Bacteriophage lysis: mechanism and regulation.

    PubMed Central

    Young, R

    1992-01-01

    Bacteriophage lysis involves at least two fundamentally different strategies. Most phages elaborate at least two proteins, one of which is a murein hydrolase, or lysin, and the other is a membrane protein, which is given the designation holin in this review. The function of the holin is to create a lesion in the cytoplasmic membrane through which the murein hydrolase passes to gain access to the murein layer. This is necessary because phage-encoded lysins never have secretory signal sequences and are thus incapable of unassisted escape from the cytoplasm. The holins, whose prototype is the lambda S protein, share a common organization in terms of the arrangement of charged and hydrophobic residues, and they may all contain at least two transmembrane helical domains. The available evidence suggests that holins oligomerize to form nonspecific holes and that this hole-forming step is the regulated step in phage lysis. The correct scheduling of the lysis event is as much an essential feature of holin function as is the hole formation itself. In the second strategy of lysis, used by the small single-stranded DNA phage phi X174 and the single-stranded RNA phage MS2, no murein hydrolase activity is synthesized. Instead, there is a single species of small membrane protein, unlike the holins in primary structure, which somehow causes disruption of the envelope. These lysis proteins function by activation of cellular autolysins. A host locus is required for the lytic function of the phi X174 lysis gene E. Images PMID:1406491

  19. Bacteriophage Protein–Protein Interactions

    PubMed Central

    Häuser, Roman; Blasche, Sonja; Dokland, Terje; Haggård-Ljungquist, Elisabeth; von Brunn, Albrecht; Salas, Margarita; Casjens, Sherwood; Molineux, Ian

    2012-01-01

    Bacteriophages T7, λ, P22, and P2/P4 (from Escherichia coli), as well as ϕ29 (from Bacillus subtilis), are among the best-studied bacterial viruses. This chapter summarizes published protein interaction data of intraviral protein interactions, as well as known phage–host protein interactions of these phages retrieved from the literature. We also review the published results of comprehensive protein interaction analyses of Pneumococcus phages Dp-1 and Cp-1, as well as coliphages λ and T7. For example, the ≈55 proteins encoded by the T7 genome are connected by ≈43 interactions with another ≈15 between the phage and its host. The chapter compiles published interactions for the well-studied phages λ (33 intra-phage/22 phage-host), P22 (38/9), P2/P4 (14/3), and ϕ29 (20/2). We discuss whether different interaction patterns reflect different phage lifestyles or whether they may be artifacts of sampling. Phages that infect the same host can interact with different host target proteins, as exemplified by E. coli phage λ and T7. Despite decades of intensive investigation, only a fraction of these phage interactomes are known. Technical limitations and a lack of depth in many studies explain the gaps in our knowledge. Strategies to complete current interactome maps are described. Although limited space precludes detailed overviews of phage molecular biology, this compilation will allow future studies to put interaction data into the context of phage biology. PMID:22748812

  20. An Undergraduate Laboratory Activity Demonstrating Bacteriophage Specificity†

    PubMed Central

    Allen, Mary E.; Gyure, Ruth A.

    2013-01-01

    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). PMID:23858357

  1. Bacteriophages as surface and ground water tracers

    NASA Astrophysics Data System (ADS)

    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.

  2. ADSORPTION OF BACTERIOPHAGES ON CLAY MINERALS

    EPA Science Inventory

    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

  3. Molecular Biology and Biotechnology of Bacteriophage

    NASA Astrophysics Data System (ADS)

    Onodera, Kazukiyo

    The development of the molecular biology of bacteriophage such as T4, lambda and filamentous phages was described and the process that the fundamental knowledge obtained in this field has subsequently led us to the technology of phage display was introduced.

  4. Comparative genomics of Shiga toxin encoding bacteriophages

    PubMed Central

    2012-01-01

    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. PMID:22799768

  5. STUDIES ON THE PURIFICATION OF BACTERIOPHAGE.

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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, Chuntae; Oh, Jin-Woo

    2015-01-01

    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.

  7. Functional relationship between bacteriophages G4 and phi X174.

    PubMed Central

    Borrias, W E; Hagenaar, M; Van Den Brekel, R; Kühlemeijer, C; Weisbeek, P J

    1979-01-01

    Mutants of bacteriophage G4 were isolated and characterized, and their mutations were mapped. They constitute six different genes, namely, A, B, E, F, G, and H. The functional relationship with bacteriophage phi X174 was determined by complementation experiments using amber mutants of phi X and amber mutants of G4. Bacteriophage phi X was able to use the products of G4 genes E, F, G, and H. In bacteriophage G4, however, only the phi X gene H product was functional. Images PMID:480475

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

    PubMed

    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.

  9. Bacteriophage exclusion, a new defense system.

    PubMed

    Barrangou, Rodolphe; van der Oost, John

    2015-01-13

    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.

  10. Application of bacteriophages in sensor development.

    PubMed

    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.

  11. Detection of bacteria with bioluminescent reporter bacteriophage.

    PubMed

    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.

  12. Bacteriophage ecology in environmental biotechnology processes.

    PubMed

    Shapiro, Orr H; Kushmaro, Ariel

    2011-06-01

    Heterotrophic bacteria are an integral part of any environmental biotechnology process (EBP). Therefore, factors controlling bacterial abundance, activity, and community composition are central to the understanding of such processes. Among these factors, top-down control by bacteriophage predation has so far received very limited attention. With over 10(8) particles per ml, phage appear to be the most numerous biological entities in EBP. Phage populations in EBP appear to be highly dynamic and to correlate with the population dynamics of their hosts and genomic evidence suggests bacteria evolve to avoid phage predation. Clearly, there is much to learn regarding bacteriophage in EBP before we can truly understand the microbial ecology of these globally important systems. PMID:21354780

  13. A novel approach for separating bacteriophages from other bacteriophages using affinity chromatography and phage display

    PubMed Central

    Ceglarek, Izabela; Piotrowicz, Agnieszka; Lecion, Dorota; Miernikiewicz, Paulina; Owczarek, Barbara; Hodyra, Katarzyna; Harhala, Marek; Górski, Andrzej; Dąbrowska, Krystyna

    2013-01-01

    Practical applications of bacteriophages in medicine and biotechnology induce a great need for technologies of phage purification. None of the popular methods offer solutions for separation of a phage from another similar phage. We used affinity chromatography combined with competitive phage display (i) to purify T4 bacteriophage from bacterial debris and (ii) to separate T4 from other contaminating bacteriophages. In ‘competitive phage display’ bacterial cells produced both wild types of the proteins (expression from the phage genome) and the protein fusions with affinity tags (expression from the expression vectors). Fusion proteins were competitively incorporated into the phage capsid. It allowed effective separation of T4 from a contaminating phage on standard affinity resins. PMID:24225840

  14. Microneedle-mediated transdermal bacteriophage delivery

    PubMed Central

    Ryan, Elizabeth; Garland, Martin J.; Singh, Thakur Raghu Raj; Bambury, Eoin; O’Dea, John; Migalska, Katarzyna; Gorman, Sean P.; McCarthy, Helen O.; Gilmore, Brendan F.; Donnelly, Ryan F.

    2012-01-01

    Interest in bacteriophages as therapeutic agents has recently been reawakened. Parenteral delivery is the most routinely-employed method of administration. However, injection of phages has numerous disadvantages, such as the requirement of a health professional for administration and the possibility of cross-contamination. Transdermal delivery offers one potential means of overcoming many of these problems. The present study utilized a novel poly (carbonate) (PC) hollow microneedle (MN) device for the transdermal delivery of Escherichia coli-specific T4 bacteriophages both in vitro and in vivo. MN successfully achieved bacteriophage delivery in vitro across dermatomed and full thickness skin. A concentration of 2.67 × 106 PFU/ml (plaque forming units per ml) was detected in the receiver compartment when delivered across dermatomed skin and 4.0 × 103 PFU/ml was detected in the receiver compartment when delivered across full thickness skin. An in vivo study resulted in 4.13 × 103 PFU/ml being detected in blood 30 min following initial MN-mediated phage administration. Clearance occurred rapidly, with phages being completely cleared from the systemic circulation within 24 h, which was expected in the absence of infection. We have shown here that MN-mediated delivery allows successful systemic phage absorption. Accordingly, bacteriophage-based therapeutics may now have an alternative route for systemic delivery. Once fully-investigated, this could lead to more widespread investigation of these interesting therapeutic viruses. PMID:22750416

  15. Drugs against superbugs: private lessons from bacteriophages.

    PubMed

    Brown, Eric D

    2004-09-01

    Bacterial genomics has provided a plethora of potential targets for antibacterial drug discovery, however, success in the hunt for new antibiotics will hinge on selecting targets with the highest potential. A recent paper by Liu and coworkers describes a new approach to target selection that uncovers strategies used by bacteriophage to disable bacteria. The method uses key phage proteins to identify and validate vulnerable targets and exploits them further in the identification of new antibacterial leads.

  16. Genomic impact of CRISPR immunization against bacteriophages.

    PubMed

    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.

  17. Going viral: designing bioactive surfaces with bacteriophage.

    PubMed

    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.

  18. Genetically modified bacteriophages in applied microbiology.

    PubMed

    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.

  19. THE PREPARATION OF RELATIVELY PURE BACTERIOPHAGE.

    PubMed

    Krueger, A P; Tamada, H T

    1929-11-20

    The method described above, based on the electrophoretic migration of bacteriophage particles into an agar gel and their subsequent re-suspension in a suitable medium, has the following advantages: It is simple and can be readily carried out on a comparatively large scale by merely inserting additional units between the same electrode cups. It requires but one extraction and the resulting phage suspension is strongly lytic, an average sample being capable of completely lysing susceptible bacteria at a dilution of 10(-16). The suspension contains no proteins demonstrable by the biuret, alcohol, xanthoproteic, Millon or Hopkins-Cole reactions and yields but 0.044 mg. N/cc. directly attributable to the phage. Each corpuscle contains no more nitrogen than a single molecule of protein. In addition the method is applicable to determinations of the electric charge carried by biologically active substances of small dimensions, e.g., phage, toxins, and perhaps some viruses. It offers as well a possible means of purification of these substances. The purified bacteriophage obtained by such a procedure or similar ones is relatively unstable. Work now in progress indicates that it does not possess nearly the resistance to chemical agents, drying, etc., that non-purified phage displays. It is suggested that experiments designed to test the therapeutic value of bacteriophage be conducted, when possible, with purified suspensions thereby avoiding any possibility of obscure non-specific reactions due to other constituents of the lysates.

  20. Genetically modified bacteriophages in applied microbiology.

    PubMed

    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

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

    PubMed

    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.

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

    PubMed

    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

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

    PubMed

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

    PubMed

    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.

  5. Expression of a bioactive bacteriophage endolysin in Nicotiana benthamiana plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The emergence and spread of antibiotic-resistant pathogens has led to an increased interest in alternative antimicrobial treatments, such as bacteriophage, bacteriophage-encoded peptidoglycan hydrolases (endolysins) and antimicrobial peptides. In our study, the antimicrobial activity of the CP933 en...

  6. Potential of Bacteriophage to Prevent and Treat Poultry Diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacteriophage are viruses plentiful in nature that kill bacteria, and represent a safe alternative to antibiotics. Bacteriophage lytic to Escherichia coli were isolated from municipal waste water treatment and poultry processing plants. This E. coli isolate is pathogenic to poultry, causing a sev...

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

    PubMed

    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).

  8. The effects of bacteriophage and nanoparticles on microbial processes

    NASA Astrophysics Data System (ADS)

    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.

  9. M13 Bacteriophage Based Protein Sensors

    NASA Astrophysics Data System (ADS)

    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.

  10. Bacterial genome remodeling through bacteriophage recombination.

    PubMed

    Menouni, Rachid; Hutinet, Geoffrey; Petit, Marie-Agnès; Ansaldi, Mireille

    2015-01-01

    Bacteriophages co-exist and co-evolve with their hosts in natural environments. Virulent phages lyse infected cells through lytic cycles, whereas temperate phages often remain dormant and can undergo lysogenic or lytic cycles. In their lysogenic state, prophages are actually part of the host genome and replicate passively in rhythm with host division. However, prophages are far from being passive residents: they can modify or bring new properties to their host. In this review, we focus on two important phage-encoded recombination mechanisms, i.e. site-specific recombination and homologous recombination, and how they remodel bacterial genomes. PMID:25790500

  11. Bacterial genome remodeling through bacteriophage recombination.

    PubMed

    Menouni, Rachid; Hutinet, Geoffrey; Petit, Marie-Agnès; Ansaldi, Mireille

    2015-01-01

    Bacteriophages co-exist and co-evolve with their hosts in natural environments. Virulent phages lyse infected cells through lytic cycles, whereas temperate phages often remain dormant and can undergo lysogenic or lytic cycles. In their lysogenic state, prophages are actually part of the host genome and replicate passively in rhythm with host division. However, prophages are far from being passive residents: they can modify or bring new properties to their host. In this review, we focus on two important phage-encoded recombination mechanisms, i.e. site-specific recombination and homologous recombination, and how they remodel bacterial genomes.

  12. Bacteriophage lambda-based expression vectors.

    PubMed

    Christensen, A C

    2001-03-01

    Bacteriophage lambda has been in use as a cloning vector for over 25 years, and has been used extensively as an expression vector. The efficiency of packaging and infection, and the simplicity of plaque screening are advantages of lambda as a cloning vector. A number of ingenious modifications help overcome the disadvantages associated with its mode of growth and its size. Some lambda vectors have been designed to be readily converted into plasmids or phagemids, and there are a variety of promoters and fusions that can be used to drive expression of foreign genes. Screening lambda libraries with antibodies or ligands is a powerful way of identifying novel genes. PMID:11434310

  13. Bacteriophage biosensors for antibiotic-resistant bacteria.

    PubMed

    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.

  14. Bacteriophage Infecting the Myxobacterium Chondrococcus columnaris

    PubMed Central

    Kingsbury, David T.; Ordal, Erling J.

    1966-01-01

    Kingsbury, David T. (University of Washington, Seattle), and Erling J. Ordal. Bacteriophage infecting the myxobacterium Chondrococcus columnaris. J. Bacteriol. 91:1327–1332. 1966.—During a series of screening experiments, seven bacteriophages which infect the pathogenic myxobacterium Chondrococcus columnaris were isolated. Of these, one was chosen for detailed study. This phage has a wide host range among strains of C. columnaris, but does not infect other myxobacterial species tested. Morphologically, this phage resembles coliphage T2, though it is smaller. It has a head diameter of 600 A, a tail length of 1,000 A, and a tail width of 200 A. The head is attached to the tail by a well-defined neck. The turbid plaques produced by this phage are similar in appearance to those produced by coliphage λ, and average 1 mm in diameter. The phage has a latent period of 100 min, a rise period of an additional 90 min, and a burst size of 23. Calcium ions at a concentration of 0.004 m are required for adsorption. This requirement cannot be met by substitution of magnesium ions. A purified preparation of 2 × 1012 phage particles was extracted with phenol, and the nucleic acid was identified as deoxyribonucleic acid (DNA). Base ratios of the phage DNA and the DNA of two propagating strains were similar. Streptomycin at a concentration of 70 μg/ml inhibits phage infection at an early stage, probably by inhibiting injection of the phage DNA. Images PMID:5929758

  15. Bacteriophage recombination systems and biotechnical applications.

    PubMed

    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

  16. Making temporal maps using bacterial luciferase: Bacteriophage

    NASA Astrophysics Data System (ADS)

    Kuhn, Jonathan; Broza, Rachel; Verkin, Ekaterina

    2004-06-01

    A method for making temporal maps in bacteria, plasmids and bacteriophages is described. A cassette containing both the genes for bacterial luciferase and kanamycin resistance can be introduced at precise sites. The technique involves clonging followed by genetic recombination. The result is formation of structures that have the luciferase genes in place of the normal DNA and this allows the very precise measurement of transcription/translation of the substituted regions. Very low levels of transcription as well as the kinetics of induction can be easily ascertained. As a specific demonstration of this general method, the technique was used with bacteriophage λ, one of the best known organisms. By measuring light emission, the expression of luciferase was followed after induction for both early and late genes. The exact timing of initial expression of genes was also determined by sampling at very short intervals. The results show that the early genes express almost without delay implying that the function of the N antitermination system is not temporal regulation.

  17. Bacteriophage recombination systems and biotechnical applications.

    PubMed

    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.

  18. Forces during Bacteriophage DNA Packaging and Ejection

    PubMed Central

    Purohit, Prashant K.; Inamdar, Mandar M.; Grayson, Paul D.; Squires, Todd M.; Kondev, Jané; Phillips, Rob

    2005-01-01

    The conjunction of insights from structural biology, solution biochemistry, genetics, and single-molecule biophysics has provided a renewed impetus for the construction of quantitative models of biological processes. One area that has been a beneficiary of these experimental techniques is the study of viruses. In this article we describe how the insights obtained from such experiments can be utilized to construct physical models of processes in the viral life cycle. We focus on dsDNA bacteriophages and show that the bending elasticity of DNA and its electrostatics in solution can be combined to determine the forces experienced during packaging and ejection of the viral genome. Furthermore, we quantitatively analyze the effect of fluid viscosity and capsid expansion on the forces experienced during packaging. Finally, we present a model for DNA ejection from bacteriophages based on the hypothesis that the energy stored in the tightly packed genome within the capsid leads to its forceful ejection. The predictions of our model can be tested through experiments in vitro where DNA ejection is inhibited by the application of external osmotic pressure. PMID:15556983

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

    PubMed

    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.

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

    PubMed

    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. PMID:27582740

  1. Antimicrobial bacteriophage-derived proteins and therapeutic applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    PubMed Central

    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. PMID:27582740

  3. Bacteriophage-based nanoprobes for rapid bacteria separation.

    PubMed

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

    2015-10-21

    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.

  4. Infrared Investigations.

    ERIC Educational Resources Information Center

    Lascours, Jean; Albe, Virginie

    2001-01-01

    Describes a series of simple and nontraditional experiments that enable students to discover the properties of infrared radiation by studying the propagation, reflection, diffusion, and refraction of infrared. The experiments rely on two modules, an infrared transmitter and an infrared receiver. (SAH)

  5. Genome Sequences of Three Novel Bacillus cereus Bacteriophages.

    PubMed

    Grose, Julianne H; Jensen, Jordan D; Merrill, Bryan D; Fisher, Joshua N B; Burnett, Sandra H; Breakwell, Donald P

    2014-01-01

    The Bacillus cereus group is an assemblage of highly related firmicute bacteria that cause a variety of diseases in animals, including insects and humans. We announce three high-quality, complete genome sequences of bacteriophages we isolated from soil samples taken at the bases of fruit trees in Utah County, Utah. While two of the phages (Shanette and JL) are highly related myoviruses, the bacteriophage Basilisk is a siphovirus.

  6. Bacteriophage-based nanoprobes for rapid bacteria separation

    NASA Astrophysics Data System (ADS)

    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

  7. Lytic bacteriophages reduce Escherichia coli O157

    PubMed Central

    Ferguson, Sean; Roberts, Cheryl; Handy, Eric; Sharma, Manan

    2013-01-01

    The role of lytic bacteriophages in preventing cross contamination of produce has not been evaluated. A cocktail of three lytic phages specific for E. coli O157:H7 (EcoShield™) or a control (phosphate buffered saline, PBS) was applied to lettuce by either; (1) immersion of lettuce in 500 ml of EcoShield™ 8.3 log PFU/ml or 9.8 log PFU/ml for up to 2 min before inoculation with E. coli O157:H7; (2) spray-application of EcoShield™ (9.3 log PFU/ml) to lettuce after inoculation with E. coli O157:H7 (4.10 CFU/cm2) following exposure to 50 μg/ml chlorine for 30 sec. After immersion studies, lettuce was spot-inoculated with E. coli O157:H7 (2.38 CFU/cm2). Phage-treated, inoculated lettuce pieces were stored at 4°C for and analyzed for E. coli O157:H7 populations for up to 7 d. Immersion of lettuce in 9.8 log PFU/ml EcoShield™ for 2 min significantly (p < 0.05) reduced E. coli O157:H7 populations after 24 h when stored at 4°C compared with controls. Immersion of lettuce in suspensions containing high concentrations of EcoShield™ (9.8 log PFU/ml) resulted in the deposition of high concentrations (7.8 log log PFU/cm2) of bacteriophages on the surface of fresh cut lettuce, potentially contributing to the efficacy of the lytic phages on lettuce. Spraying phages on to inoculated fresh cut lettuce after being washed in hypochlorite solution was significantly more effective in reducing E. coli O157:H7 populations (2.22 log CFU/cm2) on day 0 compared with control treatments (4.10 log CFU/cm2). Both immersion and spray treatments provided protection from E. coli O157:H7 contamination on lettuce, but spray application of lytic bacteriophages to lettuce was more effective in immediately reducing E. coli O157:H7 populations fresh cut lettuce. PMID:23819106

  8. Simulated hatchery system to assess bacteriophage efficacy against Vibrio harveyi.

    PubMed

    Raghu Patil, J; Desai, Srividya Narayanamurthy; Roy, Panchali; Durgaiah, Murali; Saravanan, R Sanjeev; Vipra, Aradhana

    2014-12-01

    Vibriosis caused by luminous Vibrio harveyi commonly contributes to poor survival in shrimp hatcheries and aquaculture ponds. Lytic bacteriophages pathogenic for V. harveyi are currently being investigated as an alternative to antibiotics to prevent vibriosis. Here, 8 bacteriophages were isolated from oysters and clams using V. harveyi strains as baiting hosts. Among these bacteriophages, 1 strain (VHP6b) identified as broadly pathogenic for 27 V. harveyi strains examined was further characterized by electron microscopy and genome sequence analysis. Phage VHP6b possessed a tail and morphology consistent with it being a member of the family Siphoviridae, and its genome and proteome were most closely related to the Vibrio phages SSP02 and MAR10. An integrase gene essential for lysogeny was not evident. The ability of bacteriophage VHP6b to protect shrimp postlarvae against vibriosis caused by V. harveyi strain VH6 was demonstrated in a model system designed to simulate typical hatchery conditions. Bacteriophage treatment improved survival of postlarvae by 40 to 60% under these conditions, so therapies based on this or other bacteriophages may be useful in shrimp hatcheries.

  9. Bacteriophage Lambda: a Paradigm Revisited ▿

    PubMed Central

    Fogg, Paul C. M.; Allison, Heather E.; Saunders, Jon R.; McCarthy, Alan J.

    2010-01-01

    Bacteriophage lambda has an archetypal immunity system, which prevents the superinfection of its Escherichia coli lysogens. It is now known that superinfection can occur with toxigenic lambda-like phages at a high frequency, and here we demonstrate that the superinfection of a lambda lysogen can lead to the acquisition of additional lambda genomes, which was confirmed by Southern hybridization and quantitative PCR. As many as eight integration events were observed but at a very low frequency (6.4 × 10−4) and always as multiple insertions at the established primary integration site in E. coli. Sequence analysis of the complete immunity region demonstrated that these multiply infected lysogens were not immunity mutants. In conclusion, although lambda superinfection immunity can be confounded, it is a rare event. PMID:20375161

  10. The Replication System of Bacteriophage T7.

    PubMed

    Kulczyk, A W; Richardson, C C

    2016-01-01

    The replication system of bacteriophage T7 is remarkable in that the 40,000 nucleotide genome is replicated over 100-fold in a matter of minutes. In order to accomplish this feat T7 has evolved an efficient and economical process for the replication of its DNA. The T7 replisome provides a model system to study DNA replication. Four proteins are sufficient for reconstitution of the functional replication complex, yet the assembled replisome recapitulates all the key features of more complex prokaryotic and eukaryotic systems. In this review, we describe chemical mechanisms employed by individual proteins at the replication fork. Integration of structural, biochemical, and single-molecule data reveals a compelling view on how a nearly 1-MDa molecular machine acts as a unit to synthetize the two antiparallel DNA strands in a coordinated fashion.

  11. Why Be Temperate: Lessons from Bacteriophage λ.

    PubMed

    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

  12. Why Be Temperate: Lessons from Bacteriophage λ.

    PubMed

    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.

  13. Bacteriophage lambda: early pioneer and still relevant

    PubMed Central

    Casjens, Sherwood R.; Hendrix, Roger W.

    2015-01-01

    Molecular genetic research on bacteriophage lambda carried out during its golden age from the mid 1950's to mid 1980's was critically important in the attainment of our current understanding of the sophisticated and complex mechanisms by which the expression of genes is controlled, of DNA virus assembly and of the molecular nature of lysogeny. The development of molecular cloning techniques, ironically instigated largely by phage lambda researchers, allowed many phage workers to switch their efforts to other biological systems. Nonetheless, since that time the ongoing study of lambda and its relatives have continued to give important new insights. In this review we give some relevant early history and describe recent developments in understanding the molecular biology of lambda's life cycle. PMID:25742714

  14. Bacteriophage endolysins: applications for food safety.

    PubMed

    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.

  15. Montmorillonite-induced Bacteriophage φ6 Disassembly

    NASA Astrophysics Data System (ADS)

    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.

  16. Bacteriophage cocktail for biocontrol of Salmonella in dried pet food.

    PubMed

    Heyse, Serena; Hanna, Leigh Farris; Woolston, Joelle; Sulakvelidze, Alexander; Charbonneau, Duane

    2015-01-01

    Human salmonellosis has been associated with contaminated pet foods and treats. Therefore, there is interest in identifying novel approaches for reducing the risk of Salmonella contamination within pet food manufacturing environments. The use of lytic bacteriophages shows promise as a safe and effective way to mitigate Salmonella contamination in various food products. Bacteriophages are safe, natural, highly targeted antibacterial agents that specifically kill bacteria and can be targeted to kill food pathogens without affecting other microbiota. In this study, we show that a cocktail containing six bacteriophages had a broadspectrum activity in vitro against a library of 930 Salmonella enterica strains representing 44 known serovars. The cocktail was effective against 95% of the strains in this tested library. In liquid culture dose-ranging experiments, bacteriophage cocktail concentrations of ≥10(8) PFU/ml inactivated more than 90% of the Salmonella population (10(1) to 10(3) CFU/ml). Dried pet food inoculated with a mixture containing equal proportions of Salmonella serovars Enteritidis (ATCC 4931), Montevideo (ATCC 8387), Senftenberg (ATCC 8400), and Typhimurium (ATCC 13311) and then surface treated with the six-bacteriophage cocktail (≥2.5 ± 1.5 × 10(6) PFU/g) achieved a greater than 1-log (P < 0.001) reduction compared with the phosphate-buffered saline-treated control in measured viable Salmonella within 60 min. Moreover, this bacteriophage cocktail reduced natural contamination in samples taken from an undistributed lot of commercial dried dog food that tested positive for Salmonella. Our results indicate that bacteriophage biocontrol of S. enterica in dried pet food is technically feasible.

  17. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato....

  18. 40 CFR 180.1307 - Bacteriophage of Clavibacter michiganensis subspecies michiganensis; exemption from the...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Bacteriophage of Clavibacter... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1307 Bacteriophage of... exemption from the requirement of a tolerance is established for residues of lytic bacteriophage...

  19. 40 CFR 180.1307 - Bacteriophage of Clavibacter michiganensis subspecies michiganensis; exemption from the...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bacteriophage of Clavibacter... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1307 Bacteriophage of... exemption from the requirement of a tolerance is established for residues of lytic bacteriophage...

  20. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato....

  1. 40 CFR 180.1307 - Bacteriophage of Clavibacter michiganensis subspecies michiganensis; exemption from the...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bacteriophage of Clavibacter... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1307 Bacteriophage of... exemption from the requirement of a tolerance is established for residues of lytic bacteriophage...

  2. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato....

  3. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato....

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

    PubMed

    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.

  5. Bacteriophage resistance in Escherichia coli K-12: general pattern of resistance.

    PubMed Central

    Hancock, R E; Reeves, P

    1975-01-01

    Resistant mutants were isolated to 42 virulent bacteriophages in one strain of Escherichia coli K-12 and tested for resistance or sensitivity to a set of 56 bacteriophages. Most of the mutants fell into 11 groups with respect to their resistance patterns. It was possible to classify the bacteriophages broadly, according to the variety of mutants that were resistant to them. PMID:1090611

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

    PubMed

    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

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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.

  10. Bacteriophage Infection of Model Metal Reducing Bacteria

    NASA Astrophysics Data System (ADS)

    Weber, K. A.; Bender, K. S.; Gandhi, K.; Coates, J. D.

    2008-12-01

    Microbially-mediated metal reduction plays a significant role controlling contaminant mobility in aqueous, soil, and sedimentary environments. From among environmentally relevant microorganisms mediating metal reduction, Geobacter spp. have been identified as predominant metal-reducing bacteria under acetate- oxidizing conditions. Due to the significance of these bacteria in environmental systems, it is necessary to understand factors influencing their metabolic physiology. Examination of the annotated finished genome sequence of G. sulfurreducens PCA, G. uraniumreducens Rf4, G. metallireduceans GS-15 as well as a draft genome sequence of Geobacter sp. FRC-32 have identified gene sequences of putative bacteriophage origin. Presence of these sequences indicates that these bacteria are susceptible to phage infection. Polymerase chain reaction (PCR) primer sets designed tested for the presence of 12 of 25 annotated phage-like sequences in G. sulfurreducens PCA and 9 of 17 phage-like sequences in FRC- 32. The following genes were successfully amplified in G. sulfurreducens PCA: prophage type transcription regulator, phage-induced endonuclease, phage tail sheath, 2 phage tail proteins, phage protein D, phage base plate protein, phage-related DNA polymerase, integrase, phage transcriptional regulator, and Cro-like transcription regulator. Nine of the following sequences were present in FRC-32: 4 separate phage- related proteins, phage-related tail component, viron core protein, phage Mu protein, phage base plate, and phage tail sheath. In addition to the bioinformatics evidence, incubation of G. sulfurreducens PCA with 1 μg mL-1 mytomycin C (mutagen stimulating prophage induction) during mid-log phase resulted in significant cell lysis relative to cultures that remained unamended. Cell lysis was concurrent with an increase in viral like particles enumerated using epifluorescent microscopy. In addition, samples collected following this lytic event (~44hours) were

  11. A bacteriophage endolysin that eliminates intracellular streptococci

    PubMed Central

    Shen, Yang; Barros, Marilia; Vennemann, Tarek; Gallagher, D Travis; Yin, Yizhou; Linden, Sara B; Heselpoth, Ryan D; Spencer, Dennis J; Donovan, David M; Moult, John; Fischetti, Vincent A; Heinrich, Frank; Lösche, Mathias; Nelson, Daniel C

    2016-01-01

    PlyC, a bacteriophage-encoded endolysin, lyses Streptococcus pyogenes (Spy) on contact. Here, we demonstrate that PlyC is a potent agent for controlling intracellular Spy that often underlies refractory infections. We show that the PlyC holoenzyme, mediated by its PlyCB subunit, crosses epithelial cell membranes and clears intracellular Spy in a dose-dependent manner. Quantitative studies using model membranes establish that PlyCB interacts strongly with phosphatidylserine (PS), whereas its interaction with other lipids is weak, suggesting specificity for PS as its cellular receptor. Neutron reflection further substantiates that PlyC penetrates bilayers above a PS threshold concentration. Crystallography and docking studies identify key residues that mediate PlyCB–PS interactions, which are validated by site-directed mutagenesis. This is the first report that a native endolysin can traverse epithelial membranes, thus substantiating the potential of PlyC as an antimicrobial for Spy in the extracellular and intracellular milieu and as a scaffold for engineering other functionalities. DOI: http://dx.doi.org/10.7554/eLife.13152.001 PMID:26978792

  12. Sampling Submicron T1 Bacteriophage Aerosols

    PubMed Central

    Harstad, J. Bruce

    1965-01-01

    Liquid impingers, filter papers, and fritted bubblers were partial viable collectors of radioactive submicron T1 bacteriophage aerosols at 30, 55, and 85% relative humidity. Sampler differences for viable collection were due to incomplete physical collection (slippage) and killing of phage by the samplers. Dynamic aerosols of a mass median diameter of 0.2 μ were produced with a Dautrebande generator from concentrated aqueous purified phage suspensions containing extracellular soluble radioactive phosphate as a physical tracer. There was considerable destruction of phage by the Dautrebande generator; phage titers of the Dautrebande suspension decreased exponentially, but there was a progressive (linear) increase in tracer titers. Liquid impingers recovered the most viable phage but allowed considerable (30 to 48%) slippage, which varies inversely with the aerosol relative humidity. Filter papers were virtually complete physical collectors of submicron particles but were the most destructive. Fritted bubbler slippage was more than 80%. With all samplers, phage kill was highest at 85% relative humidity and lowest at 55% relative humidity. An electrostatic precipitator was used to collect aerosol samples for particle sizing with an electron microscope. The particle size was slightly larger at 85% relative humidity than at 30 or 55% relative humidity. Images Fig. 1 Fig. 4 PMID:5866038

  13. A bacteriophage endolysin that eliminates intracellular streptococci.

    PubMed

    Shen, Yang; Barros, Marilia; Vennemann, Tarek; Gallagher, D Travis; Yin, Yizhou; Linden, Sara B; Heselpoth, Ryan D; Spencer, Dennis J; Donovan, David M; Moult, John; Fischetti, Vincent A; Heinrich, Frank; Lösche, Mathias; Nelson, Daniel C

    2016-01-01

    PlyC, a bacteriophage-encoded endolysin, lyses Streptococcus pyogenes (Spy) on contact. Here, we demonstrate that PlyC is a potent agent for controlling intracellular Spy that often underlies refractory infections. We show that the PlyC holoenzyme, mediated by its PlyCB subunit, crosses epithelial cell membranes and clears intracellular Spy in a dose-dependent manner. Quantitative studies using model membranes establish that PlyCB interacts strongly with phosphatidylserine (PS), whereas its interaction with other lipids is weak, suggesting specificity for PS as its cellular receptor. Neutron reflection further substantiates that PlyC penetrates bilayers above a PS threshold concentration. Crystallography and docking studies identify key residues that mediate PlyCB-PS interactions, which are validated by site-directed mutagenesis. This is the first report that a native endolysin can traverse epithelial membranes, thus substantiating the potential of PlyC as an antimicrobial for Spy in the extracellular and intracellular milieu and as a scaffold for engineering other functionalities. PMID:26978792

  14. Bacteriophage based probes for pathogen detection.

    PubMed

    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.

  15. M13 bacteriophage production for large-scale applications.

    PubMed

    Warner, Christopher M; Barker, Natalie; Lee, Seung-Wuk; Perkins, Edward J

    2014-10-01

    Bacteriophage materials have the potential to revolutionize medicine, energy production and storage, agriculture, solar cells, optics and many other fields. To fulfill these needs, this study examined critical process parameters during phage propagation to increase phage production capability. A representative scale-down system was created in tube spin reactors to allow parallel experimentation with single- and multi-variable analysis. Temperature, harvest time, media composition, feed regime, bacteriophage, and bacteria concentration were analyzed in the scale-down system. Temperature, media composition, and feeding regimens were found to affect phage production more than other factors. Temperature affected bacterial growth and phage production inversely. Multi-variate analysis identified an optimal parameter space which provided a significant improvement over the base line method. This method should be useful in scaled production of bacteriophage for biotechnology.

  16. Lipopolysaccharide-specific bacteriophage for Klebsiella pneumoniae C3.

    PubMed Central

    Tomás, J M; Jofre, J T

    1985-01-01

    Bacteriophage FC3-1 is one of several specific bacteriophages of Klebsiella pneumoniae C3 isolated in our laboratory. Unlike receptors for other Klebsiella phages, the bacteriophage FC3-1 receptor was shown to be lipopolysaccharide, specifically the polysaccharide fraction (O-antigen and core region). We concluded that capsular polysaccharide, outer membrane proteins, and lipid A were not involved in phage binding. Mutants resistant to this phage were isolated and were found to be devoid of lipopolysaccharide O-antigen by several criteria but to contain capsular material serologically identical to that of the wild type. The polysaccharide fraction was concluded to be the primary phage receptor, indicating that it is available to the phage. Images PMID:3888963

  17. Considerations for using bacteriophages for plant disease control

    PubMed Central

    Jones, Jeffrey B.; Vallad, Gary E.; Iriarte, Fanny B.; Obradović, Aleksa; Wernsing, Mine H.; Jackson, Lee E.; Balogh, Botond; Hong, Jason C.; Momol, M.Timur

    2012-01-01

    The use of bacteriophages as an effective phage therapy strategy faces significant challenges for controlling plant diseases in the phyllosphere. A number of factors must be taken into account when considering phage therapy for bacterial plant pathogens. Given that effective mitigation requires high populations of phage be present in close proximity to the pathogen at critical times in the disease cycle, the single biggest impediment that affects the efficacy of bacteriophages is their inability to persist on plant surfaces over time due to environmental factors. Inactivation by UV light is the biggest factor reducing bacteriophage persistence on plant surfaces. Therefore, designing strategies that minimize this effect are critical. For instance, application timing can be altered: instead of morning or afternoon application, phages can be applied late in the day to minimize the adverse effects of UV and extend the time high populations of phage persist on leaf surfaces. Protective formulations have been identified which prolong phage viability on the leaf surface; however, UV inactivation continues to be the major limiting factor in developing more effective bacteriophage treatments for bacterial plant pathogens. Other strategies, which have been developed to potentially increase persistence of phages on leaf surfaces, rely on establishing non-pathogenic or attenuated bacterial strains in the phyllosphere that are sensitive to the phage(s) specific to the target bacterium. We have also learned that selecting the correct phages for disease control is critical. This requires careful monitoring of bacterial strains in the field to minimize development of bacterial strains with resistance to the deployed bacteriophages. We also have data that indicate that selecting the phages based on in vivo assays may also be important when developing use for field application. Although bacteriophages have potential in biological control for plant disease control, there are major

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

    PubMed

    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

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

    PubMed

    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.

  20. Genetically engineered acidophilic heterotrophic bacteria by bacteriophage transduction

    SciTech Connect

    Ward, T.E.; Bruhn, D.F.; Bulmer, D.F.

    1989-05-10

    A bacteriophage capable of infecting acidophilic heterotrophic bacteria and processes for genetically engineering acidophilic bacteria for biomining or sulfur removal from coal are disclosed. The bacteriophage is capable of growth in cells existing at pH at or below 3.0. Lytic forms of the phage introduced into areas experiencing acid drainage kill the bacteria causing such drainage. Lysogenic forms of the phage having genes for selective removal of metallic or nonmetallic elements can be introduced into acidophilic bacteria to effect removal of the desired element from ore or coal. 1 fig., 1 tab.

  1. Complete genome sequence of Croceibacter bacteriophage P2559S.

    PubMed

    Kang, Ilnam; Kang, Dongmin; Cho, Jang-Cheon

    2012-08-01

    Croceibacter atlanticus HTCC2559(T), a marine bacterium isolated from the Sargasso Sea, is a phylogenetically unique member of the family Flavobacteriaceae. Strain HTCC2559(T) possesses genes related to interaction with primary producers, which makes studies on bacteriophages infecting the strain interesting. Here we report the genome sequence of bacteriophage P2559S, which was isolated off the coast of the Republic of Korea and lytically infects HTCC2559(T). Many genes predicted in the P2559S genome had their homologs in Bacteroides phages.

  2. Complete genome sequence of Croceibacter bacteriophage P2559S.

    PubMed

    Kang, Ilnam; Kang, Dongmin; Cho, Jang-Cheon

    2012-08-01

    Croceibacter atlanticus HTCC2559(T), a marine bacterium isolated from the Sargasso Sea, is a phylogenetically unique member of the family Flavobacteriaceae. Strain HTCC2559(T) possesses genes related to interaction with primary producers, which makes studies on bacteriophages infecting the strain interesting. Here we report the genome sequence of bacteriophage P2559S, which was isolated off the coast of the Republic of Korea and lytically infects HTCC2559(T). Many genes predicted in the P2559S genome had their homologs in Bacteroides phages. PMID:22843867

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

    PubMed

    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.

  4. Bacteriophages of Soft Rot Enterobacteriaceae-a minireview.

    PubMed

    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. PMID:26626879

  5. Existence of lysogenic bacteriophages in Bacillus thuringiensis type strains.

    PubMed

    Roh, Jong Yul; Park, Jong Bin; Liu, Qin; Kim, Song Eun; Tao, Xueying; Choi, Tae Woong; Choi, Jae Young; Kim, Woo Jin; Jin, Byung Rae; Je, Yeon Ho

    2013-07-01

    We screened the existence of bacteriophages in 67 Bacillus thuringiensis type strains by phage DNA extraction and PCR using phage terminase small subunit (TerS)-specific primers to the supernatants and the precipitated pellets of Bt cultures, and by transmission electron microscopy. The various bacteriophages were observed from the supernatants of 22 type strains. Ten type strains showed the extracted phage DNAs and the amplified fragment by TerS PCR but 12 type strains showed only the phage DNAs. Their morphological characteristic suggests that they belong to Family Siphoviridae which had a long tail and symmetrical head. PMID:23632013

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

    PubMed

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

    2016-02-01

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

  7. Engineered enzymatically active bacteriophages and methods of uses thereof

    DOEpatents

    Collins, James J; Kobayashi, Hideki; Kearn, Mads; Araki, Michihiro; Friedland, Ari; Lu, Timothy Kuan-Ta

    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.

  8. Bacteriophages of Soft Rot Enterobacteriaceae-a minireview.

    PubMed

    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.

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

    PubMed

    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

  10. Detection and identification of Lactobacillus helveticus bacteriophages by PCR.

    PubMed

    Zago, Miriam; Rossetti, Lia; Reinheimer, Jorge; Carminati, Domenico; Giraffa, Giorgio

    2008-05-01

    A PCR protocol for detection of Lactobacillus helveticus bacteriophages was optimized. PCR was designed taking into account the sequence of the lys gene of temperate bacteriophage Phi-0303 and optimized to obtain a fragment of 222 bp using different Lb. helveticus phages from our collection. PCR was applied to total phage DNA extracted from 53 natural whey starters used for the production of Grana cheese and all gave the expected fragment. The presence of actively growing phages in the cultures was verified by traditional tests. Several PCR products of the lys gene were sequenced and aligned. The resulting sequences showed variable heterogeneity between the phages. PMID:18474137

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

    PubMed

    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.

  12. Genetic transformation in Staphylococcus aureus: demonstration of a competence-conferring factor of bacteriophage origin in bacteriophage 80 alpha lysates.

    PubMed Central

    Thompson, N E; Pattee, P A

    1981-01-01

    A virion component that is responsible for conferring competence to Staphylococcus aureus was demonstrated in lysates of bacteriophage 80 alpha, a serological group B phage. Isolated particles of 80 alpha could not be shown to confer significant levels of competence. The phage component had a density of about 1.3 g/cm3, was inactivated by pronase, and was inhibited by antiserum prepared against isolated infectious particles of a serological group B phage. Centrifugation through a Ficoll gradient resulted in separation of competence-conferring activity and plaque-forming units. It is concluded that this proteinaceous subvirion component constitutes a bona fide competence factor of bacteriophage origin. PMID:6457025

  13. Long-circulating bacteriophage as antibacterial agents.

    PubMed Central

    Merril, C R; Biswas, B; Carlton, R; Jensen, N C; Creed, G J; Zullo, S; Adhya, S

    1996-01-01

    The increased prevalence of multidrug-resistant bacterial pathogens motivated us to attempt to enhance the therapeutic efficacy of bacteriophages. The therapeutic application of phages as antibacterial agents was impeded by several factors: (i) the failure to recognize the relatively narrow host range of phages; (ii) the presence of toxins in crude phage lysates; and (iii) a lack of appreciation for the capacity of mammalian host defense systems, particularly the organs of the reticuloendothelial system, to remove phage particles from the circulatory system. In our studies involving bacteremic mice, the problem of the narrow host range of phage was dealt with by using selected bacterial strains and virulent phage specific for them. Toxin levels were diminished by purifying phage preparations. To reduce phage elimination by the host defense system, we developed a serial-passage technique in mice to select for phage mutants able to remain in the circulatory system for longer periods of time. By this approach we isolated long-circulating mutants of Escherichia coli phage lambda and of Salmonella typhimurium phage P22. We demonstrated that the long-circulating lambda mutants also have greater capability as antibacterial agents than the corresponding parental strain in animals infected with lethal doses of bacteria. Comparison of the parental and mutant lambda capsid proteins revealed that the relevant mutation altered the major phage head protein E. The use of toxin-free, bacteria-specific phage strains, combined with the serial-passage technique, may provide insights for developing phage into therapeutically effective antibacterial agents. Images Fig. 4 PMID:8622911

  14. Viscoelastic properties of semiflexible filamentous bacteriophage fd.

    PubMed

    Schmidt, F G; Hinner, B; Sackmann, E; Tang, J X

    2000-10-01

    The cytoskeletal protein filament F-actin has been treated in a number of recent studies as a model physical system for semiflexible filaments. In this work, we studied the viscoelastic properties of entangled solutions of the filamentous bacteriophage fd as an alternative to F-actin with similar physical parameters. We present both microrheometric and macrorheometric measurements of the viscoelastic storage and loss moduli, G'(f ) and G"(f ), respectively, in a frequency range 0.01

  15. Immobilization of Active Bacteriophages on Polyhydroxyalkanoate Surfaces.

    PubMed

    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

  16. The protein interaction map of bacteriophage lambda

    PubMed Central

    2011-01-01

    Background Bacteriophage lambda is a model phage for most other dsDNA phages and has been studied for over 60 years. Although it is probably the best-characterized phage there are still about 20 poorly understood open reading frames in its 48-kb genome. For a complete understanding we need to know all interactions among its proteins. We have manually curated the lambda literature and compiled a total of 33 interactions that have been found among lambda proteins. We set out to find out how many protein-protein interactions remain to be found in this phage. Results In order to map lambda's interactions, we have cloned 68 out of 73 lambda open reading frames (the "ORFeome") into Gateway vectors and systematically tested all proteins for interactions using exhaustive array-based yeast two-hybrid screens. These screens identified 97 interactions. We found 16 out of 30 previously published interactions (53%). We have also found at least 18 new plausible interactions among functionally related proteins. All previously found and new interactions are combined into structural and network models of phage lambda. Conclusions Phage lambda serves as a benchmark for future studies of protein interactions among phage, viruses in general, or large protein assemblies. We conclude that we could not find all the known interactions because they require chaperones, post-translational modifications, or multiple proteins for their interactions. The lambda protein network connects 12 proteins of unknown function with well characterized proteins, which should shed light on the functional associations of these uncharacterized proteins. PMID:21943085

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

    PubMed

    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.

  18. BACTERIOPHAGE TRANSPORT IN SANDY SOIL AND FRACTURED TUFF

    EPA Science Inventory

    Bacteriophage transport was investigated in laboratory column experiments using sandy soil, a controlled field study in a sandy wash, and laboratory experiments using fractured rock. In the soil columns, the phage MS-2 exhibited significant dispersion and was excluded from 35 to ...

  19. Complete Genome Sequence of Bacillus megaterium Bacteriophage Eldridge

    PubMed Central

    Reveille, Alexandra M.; Eldridge, Kimberly A.

    2016-01-01

    In this study the complete genome sequence of the unique bacteriophage Eldridge, isolated from soil using Bacillus megaterium as the host organism, was determined. Eldridge is a myovirus with a genome consisting of 242 genes and is unique when compared to phage sequences in GenBank. PMID:27103735

  20. Complete Genome Sequence of Bacillus thuringiensis Bacteriophage Smudge

    PubMed Central

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

    2016-01-01

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

  1. Therapeutic effects of bacteriophages against Salmonella gallinarum infection in chickens.

    PubMed

    Hong, Sung Sik; Jeong, Jipseol; Lee, Jinju; Kim, Suk; Min, Wongi; Myung, Heejoon

    2013-10-28

    In this study the isolation and characterization of three bacteriophages (ST4, L13, and SG3) infecting Salmonella gallinarum were carried out. They were further tested for their in vivo efficacy in phage therapy. All three phages belong to the Siphoviridae family with isometric heads and non-contractile tails. They have a broad host range among serovars of Salmonella enterica. The burst sizes were observed to be 1670, 80, and 28 for ST4, L13, and SG3, respectively. The in vivo efficacy of the phages was tested in chickens. Layer chickens were challenged with S. gallinarum, whereas contact chickens were cohabited without direct challenge. Each bacteriophage was orally inoculated in the form of feed additives. Mortality was observed and S. gallinarum was periodically re-isolated from the livers, spleens, and cecums of the chickens. Bacterial re-isolation from the organs and mortality decreased significantly in both challenged and contact chickens treated with the bacteriophages compared with untreated chickens serving as the control. The three bacteriophages may be effective alternatives to antibiotics for the control of fowl typhoid disease in chickens. PMID:23801253

  2. Multiple roles of genome-attached bacteriophage terminal proteins

    SciTech Connect

    Redrejo-Rodríguez, Modesto; Salas, Margarita

    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. Natural mummification of the human gut preserves bacteriophage DNA.

    PubMed

    Santiago-Rodriguez, Tasha M; Fornaciari, Gino; Luciani, Stefania; Dowd, Scot E; Toranzos, Gary A; Marota, Isolina; Cano, Raul J

    2016-01-01

    The natural mummification process of the human gut represents a unique opportunity to study the resulting microbial community structure and composition. While results are providing insights into the preservation of bacteria, fungi, pathogenic eukaryotes and eukaryotic viruses, no studies have demonstrated that the process of natural mummification also results in the preservation of bacteriophage DNA. We characterized the gut microbiome of three pre-Columbian Andean mummies, namely FI3, FI9 and FI12, and found sequences homologous to viruses. From the sequences attributable to viruses, 50.4% (mummy FI3), 1.0% (mummy FI9) and 84.4% (mummy FI12) were homologous to bacteriophages. Sequences corresponding to the Siphoviridae, Myoviridae, Podoviridae and Microviridae families were identified. Predicted putative bacterial hosts corresponded mainly to the Firmicutes and Proteobacteria, and included Bacillus, Staphylococcus, Clostridium, Escherichia, Vibrio, Klebsiella, Pseudomonas and Yersinia. Predicted functional categories associated with bacteriophages showed a representation of structural, replication, integration and entry and lysis genes. The present study suggests that the natural mummification of the human gut results in the preservation of bacteriophage DNA, representing an opportunity to elucidate the ancient phageome and to hypothesize possible mechanisms of preservation.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    PubMed

    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

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

    PubMed

    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.

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

    PubMed Central

    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

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

    PubMed

    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.

  9. Bacteriophages Limit the Existence Conditions for Conjugative Plasmids

    PubMed Central

    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

  10. Environmental Augmentation with Bacteriophage Prevents Colibacillosis in Broiler Chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 e...

  11. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2010 CFR

    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 (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices §...

  12. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices §...

  13. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices §...

  14. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices §...

  15. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices §...

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

    PubMed

    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. Complete Genome Sequence of Bacillus thuringiensis Bacteriophage Smudge.

    PubMed

    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

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

    PubMed Central

    Ross, Alexa; Ward, Samantha; Hyman, Paul

    2016-01-01

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

  19. Infrared Spectrometry.

    ERIC Educational Resources Information Center

    McDonald, Robert S.

    1984-01-01

    This review on infrared spectrometry covering the period from late 1981 to late 1983, is divided into nine sections. Topic areas include: books; reviews; analytical applications; biochemical applications; environmental applications; polymer applications; infrared instrumentation; sampling techniques; and software and algorithms. (JN)

  20. DNA packaging intermediates of bacteriophage Φ174

    PubMed Central

    Music, Cynthia L; Cheng, R Holland; Bowen, Zorina; McKenna, Robert; Rossmann, Michael G; Baker, Timothy S; Incardona, Nino L

    2014-01-01

    Background Like many viruses, bacteriophage ΦX174 packages its I)NA genome into a procapsid that is assembled from structural intermediates and scaffolding proteins. The procapsid contains the structural proteins F, G and H, as well as the scaffolding proteins B and D. Provirions are formed by packaging of DNA together with the small internal J proteins, while losing at least some of the B scaffolding proteins. Eventually, loss of the I) scaffolding proteins and the remaining B proteins leads to the formation of mature virions. Results ΦX174 108S 'procapsids' have been purified in milligram quantities by removing 114S (mature virion) and 70S (abortive capsid) particles from crude lysates by differential precipitation with polyethylene glycol. 132S 'provirions' were purified on sucrose gradients in the presence of EDTA. Cryo-electron microscopy (cryo-EM) was used to obtain reconstructions of procapsids and provirions. Although these are very similar to each other, their structures differ greatly from that of the virion. The F and G proteins, whose atomic structures in virions were previously determined from X-ray crystallography, were fitted into the cryo-EM reconstructions. This showed that the pentamer of G proteins on each five-fold vertex changes its conformation only slightly during DNA packaging and maturation, whereas major tertiary and quaternary structural changes occur in the F protein. The procapsids and provirions were found to contain 120 copies of the I) protein arranged as tetramers on the twofold axes. IDNA might enter procapsids through one of the 30 Å diameter holes on the icosahedral three-fold axes. Conclusions Combining cryo-EM image reconstruction and X-ray crystallography has revealed the major conformational changes that can occur in viral assembly. The function of the scaffolding proteins may be, in part, to support weak interactions between the structural proteins in the procapsids and to cover surfaces that are subsequently required for

  1. Infrared Measurement

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A Jet Propulsion Laboratory Technical Support Package (TSP) describing a technique for processing data from an infrared radiometer assisted a manufacturer of laminates for printed circuit boards. To reduce emissions and lower the cost of producing prepreg (a continuous glass cloth, or web, impregnated with epoxy resin and partially cured by applying heat), Norplex Oak switched to infrared treating towers. The TSP confirmed the company's computer prediction of heat flux patterns, provided information that allowed the company to modify infrared treaters for consistency, and furnished a basis for development of optimal heater placements. The treaters are now successfully operating at increased speeds with improved product consistency.

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

    PubMed

    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.

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

    PubMed

    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.

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

    NASA Technical Reports Server (NTRS)

    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. Why Infrared?

    ERIC Educational Resources Information Center

    Harris, J. R.

    1973-01-01

    Discusses applications of techniques developed for the remote sensing of infrared radiation. In addition to military applications, remote sensing has become important in collecting environmental data and detecting ecological problems. (JR)

  6. A new bacteriophage, which infects acidophilic, heterotrophic bacteria from acidic mining environments

    SciTech Connect

    Ward, T.E.; Bruhn, D.F.; Bulmer, D.K.; Watkins, C.S.; Rowland, M.L.; Winston, V.

    1989-01-01

    The genetic characteristics of members of the genus Acidiphilium are poorly understood. As part of our study of the genetics of these bacteria, a search was made for an endogenous bacteriophage. Such a bacteriophage has been discovered. Several properties of the phage have been investigated. The phage has a lambdoid morphology and is somewhat larger than lambda. A variety of factors which affect phage stability have been investigated. The bacteriophage infects several of the strains that have been tested. Study of this bacteriophage should greatly increase our understanding of genetic mechanisms in Acidiphilium. 20 refs., 3 figs., 1 tab.

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

    NASA Technical Reports Server (NTRS)

    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.

  8. Bacteriophage-based synthetic biology for the study of infectious diseases

    PubMed Central

    Lu, Timothy K.

    2014-01-01

    Since their discovery, bacteriophages have contributed enormously to our understanding of molecular biology as model systems. Furthermore, bacteriophages have provided many tools that have advanced the fields of genetic engineering and synthetic biology. Here, we discuss bacteriophage-based technologies and their application to the study of infectious diseases. New strategies for engineering genomes have the potential to accelerate the design of novel phages as therapies, diagnostics, and tools. Though almost a century has elapsed since their discovery, bacteriophages continue to have a major impact on modern biological sciences, especially with the growth of multidrug-resistant bacteria and interest in the microbiome. PMID:24997401

  9. Combined use of bacteriophage K and a novel bacteriophage to reduce Staphylococcus aureus biofilm formation.

    PubMed

    Alves, D R; Gaudion, A; Bean, J E; Perez Esteban, P; Arnot, T C; Harper, D R; Kot, W; Hansen, L H; Enright, M C; Jenkins, A Tobias A

    2014-11-01

    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 broad host range among S. aureus bacteria. Morphologically, the phage belongs to the Myoviridae family and comprises a large double-stranded DNA (dsDNA) genome of 141,907 bp. DRA88 was mixed with phage K to produce a high-titer mixture that showed strong lytic activity against a wide range of S. aureus isolates, including representatives of the major international MRSA clones and coagulase-negative Staphylococcus. Its efficacy was assessed both in planktonic cultures and when treating established biofilms produced by three different biofilm-producing S. aureus isolates. A significant reduction of biofilm biomass over 48 h of treatment was recorded in all cases. The phage mixture may form the basis of an effective treatment for infections caused by S. aureus biofilms.

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

    PubMed

    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.

  11. Combined Use of Bacteriophage K and a Novel Bacteriophage To Reduce Staphylococcus aureus Biofilm Formation

    PubMed Central

    Alves, D. R.; Gaudion, A.; Bean, J. E.; Perez Esteban, P.; Arnot, T. C.; Harper, D. R.; Kot, W.; Hansen, L. H.; Enright, M. C.

    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 broad host range among S. aureus bacteria. Morphologically, the phage belongs to the Myoviridae family and comprises a large double-stranded DNA (dsDNA) genome of 141,907 bp. DRA88 was mixed with phage K to produce a high-titer mixture that showed strong lytic activity against a wide range of S. aureus isolates, including representatives of the major international MRSA clones and coagulase-negative Staphylococcus. Its efficacy was assessed both in planktonic cultures and when treating established biofilms produced by three different biofilm-producing S. aureus isolates. A significant reduction of biofilm biomass over 48 h of treatment was recorded in all cases. The phage mixture may form the basis of an effective treatment for infections caused by S. aureus biofilms. PMID:25149517

  12. Structure of the Ribonucleic Acid Bacteriophage R17

    PubMed Central

    Vasquez, Cesar; Granboulan, Nicole; Franklin, Richard M.

    1966-01-01

    Vasquez, Cesar (Institut de Recherches sur le Cancer, Villejuif, Seine, France), Nicole Granboulan, and Richard M. Franklin. Structure of the ribonucleic acid bacteriophage R17. J. Bacteriol. 92:1779–1786. 1966.—The morphology of bacteriophage R17 was studied by electron microscopy of negatively stained virions. The hexagonal shape, the presence of a maximum of 10 units at the periphery, and especially the observation of central fivefold points of symmetry with neighboring five and six coordinated units indicated icosahedral symmetry with 32 morphological units. Although the exact shape of the polyhedron could not be specified, the number of morphological units agreed with the chemically estimated number of structural units. Images PMID:5958109

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

    PubMed Central

    2012-01-01

    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. PMID:22234269

  14. Insights into Bacteriophage Application in Controlling Vibrio Species.

    PubMed

    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

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

    PubMed

    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

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

    PubMed Central

    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

  17. Effect of HZE particles and space hadrons on bacteriophages

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

  20. Bacteriophage application to control the contaminated water with Shigella

    PubMed Central

    Jun, Jin Woo; Giri, Sib Sankar; Kim, Hyoun Joong; Yun, Sae Kil; Chi, Cheng; Chai, Ji Young; Lee, Byeong Chun; Park, Se Chang

    2016-01-01

    Shigella is one of the most important waterborne and foodborne pathogens around the world. Emergence of antibiotic-resistant Shigella has made the development of alternatives to conventional antibiotics necessary. In this study, a virulent Myoviridae bacteriophage, pSs-1 was isolated from environmental water in South Korea and showed infectivity to S. flexneri as well as S. sonnei strains. One-step growth analysis showed that pSs-1 has a short latent period (25 min) and a large burst size (97 PFU/cell). According to the genomic analysis, pSs-1 contains 164,999 bp of genome with a G + C content of 35.54% and it is considered as a member of the T4-like bacteriophage group. These results showed that pSs-1 may have potential as a biocontrol agent instead of conventional antibiotics for shigellosis. PMID:26971572

  1. The Molecular Genetics of Bacteriophage: The Work of Norton Zinder

    PubMed Central

    Kresge, Nicole; Simoni, Robert D.; Hill, Robert L.

    2011-01-01

    In 1966, Norton Zinder and Joshua Lederberg discovered that Salmonella could exchange genes via bacteriophages. They named this phenomenon “genetic transduction.” This discovery set Zinder on a lifelong journey researching bacteriophage. In the two Journal of Biological Chemistry (JBC) Classic papers reprinted here, Zinder and Nina Fedoroff present their findings on the phage f2 replicase. Properties of the Phage f2 Replicase. I. Optimal Conditions for Replicase Activity and Analysis of the Polynucleotide Product Synthesized in Vitro (Fedoroff, N. V., and Zinder, N. D. (1972) J. Biol. Chem. 247, 4577–4585) Properties of the Phage f2 Replicase. II. Comparative Studies on the Ribonucleic Acid-dependent and Poly(C)-dependent Activities of the Replicase (Fedoroff, N. V., and Zinder, N. D. (1972) J. Biol. Chem. 247, 4586–4592) PMID:21830328

  2. Bacteriophage exclusion, a new defense system

    PubMed Central

    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

  3. Insights into Bacteriophage Application in Controlling Vibrio Species

    PubMed Central

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

    PubMed

    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.

  5. Sequence and comparative analysis of Leuconostoc dairy bacteriophages.

    PubMed

    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.

  6. How long can bacteriophage λ change its mind?

    PubMed Central

    Semsey, Szabolcs; Campion, Christopher; Mohamed, Abdu; Svenningsen, Sine Lo

    2015-01-01

    A key event in the lifecycle of a temperate bacteriophage is the choice between lysis and lysogeny upon infection of a susceptible host cell. In a recent paper, we showed that a prolonged period exists after the decision to lysogenize, during which bacteriophage λ can abandon the initial decision, and instead develop lytically, as a response to the accumulation of the late lytic regulatory protein Q. Here, we present evidence that expression of Q does not induce replication of λ DNA, suggesting that the DNA to be packaged into the resulting phage progeny was already present at the time of the initial decision to lysogenize. We summarize our findings in a working model of the key determinants of the duration of the post-decision period during which it is possible for the infected cell to switch from the lysogeny decision to successful lytic development. PMID:26459429

  7. Genome Sequences of Gordonia terrae Bacteriophages Phinally and Vivi2

    PubMed Central

    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.

    2016-01-01

    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. PMID:27540050

  8. Endopeptidase and Glycosidase Activities of the Bacteriophage B30 Lysin

    PubMed Central

    Baker, John R.; Liu, Chengbao; Dong, Shengli; Pritchard, David G.

    2006-01-01

    Synthetic peptides corresponding to portions of group B streptococcal peptidoglycan were used to show that the endopeptidase activity of bacteriophage B30 lysin cleaves between d-Ala in the stem peptide and l-Ala in the cross bridge and that the minimal peptide sequence cleaved is dl-γ-Glu-Lys-d-Ala-Ala-Ala. The only glycosidase activity present is that of N-acetyl-β-d-muramidase. PMID:17021237

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

    PubMed

    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.

  10. Unusual promoter-independent transcription reactions with bacteriophage RNA polymerases.

    PubMed Central

    Krupp, G

    1989-01-01

    Efficient transcription reactions of DNA-dependent RNA polymerases require the presence of a specific promoter sequence. This report shows that in the absence of their cognate promoter, two bacteriophage RNA polymerases are capable of performing unusual transcription reactions: (i) the DNA template serves also as a primer for RNA synthesis and this leads to hybrid DNA/RNA molecules, (ii) if the DNA template forms a hairpin structure, the linear DNA can be transcribed via the 'rolling circle' mechanism. Images PMID:2471146

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

    PubMed

    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

    2016-01-01

    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. PMID:27540050

  12. Bacteriophage-insensitive mutants for high quality Crescenza manufacture

    PubMed Central

    Chirico, Donatella; Gorla, Arianna; Verga, Viola; Pedersen, Per D.; Polgatti, Eliseo; Cava, Antonio; Dal Bello, Fabio

    2014-01-01

    Streptococcus thermophilus is a thermophilic lactic acid bacterium used as starter culture for the manufacture of fermented dairy products. For the production of Crescenza and other soft cheeses, Sacco has developed and provides dairies with three different defined blends of S. thermophilus strains. Each blend contains two different S. thermophilus strains. The strains were selected based on their unique technological properties as well as different phage profiles. Analysis of 133 whey samples collected in 2009–2010 from Italian dairies showed a high prevalence (about 50%) of bacteriophage attacks on the blend ST020. More specifically, the strain S. thermophilus ST1A was found to be the preferred target of the bacteriophages. A bacteriophage insensitive mutant (BIM5) of the phage-sensitive strain ST1A was successfully developed and used to substitute strain ST1A in the Crescenza starter culture ST020. The strain BIM5 showed identical technological and industrial traits as those of the phage-sensitive strain ST1A. The improved resistance of the modified Crescenza starter culture ST020R was confirmed at Italian dairies, and its effectiveness monitored on 122 whey samples collected in 2011–2012. Compared to the previous values (2009–2010), the use of the phage-hardened blend ST020R allowed reducing of frequency of phage attacks from about 50 to less than 5% of the whey samples investigated. PMID:24834065

  13. T4 bacteriophage as a phage display platform.

    PubMed

    Gamkrelidze, Mariam; Dąbrowska, Krystyna

    2014-07-01

    Analysis of molecular events in T4-infected Escherichia coli has revealed some of the most important principles of biology, including relationships between structures of genes and their products, virus-induced acquisition of metabolic function, and morphogenesis of complex structures through sequential gene product interaction rather than sequential gene activation. T4 bacteriophages and related strains were applied in the first formulations of many fundamental biological concepts. These include the unambiguous recognition of nucleic acids as the genetic material, the definition of the gene by fine-structure mutation, recombinational and functional analyses, the demonstration that the genetic code is triplet, the discovery of mRNA, the importance of recombination and DNA replications, light-dependent and light-independent DNA repair mechanisms, restriction and modification of DNA, self-splicing of intron/exon arrangement in prokaryotes, translation bypassing and others. Bacteriophage T4 possesses unique features that make it a good tool for a multicomponent vaccine platform. Hoc/Soc-fused antigens can be assembled on the T4 capsid in vitro and in vivo. T4-based phage display combined with affinity chromatography can be applied as a new method for bacteriophage purification. The T4 phage display system can also be used as an attractive approach for cancer therapy. The data show the efficient display of both single and multiple HIV antigens on the phage T4 capsid and offer insights for designing novel particulate HIV or other vaccines that have not been demonstrated by other vector systems.

  14. Host adaption to the bacteriophage carrier state of Campylobacter jejuni.

    PubMed

    Brathwaite, Kelly J; Siringan, Patcharin; Connerton, Phillippa L; Connerton, Ian F

    2015-01-01

    The carrier state of the foodborne pathogen Campylobacter jejuni represents an alternative life cycle whereby virulent bacteriophages can persist in association with host bacteria without commitment to lysogeny. Host bacteria exhibit significant phenotypic changes that improve their ability to survive extra-intestinal environments, but exhibit growth-phase-dependent impairment in motility. We demonstrate that early exponential phase cultures become synchronised with respect to the non-motile phenotype, which corresponds with a reduction in their ability to adhere to and invade intestinal epithelial cells. Comparative transcriptome analyses (RNA-seq) identify changes in gene expression that account for the observed phenotypes: downregulation of stress response genes hrcA, hspR and per and downregulation of the major flagellin flaA with the chemotactic response signalling genes cheV, cheA and cheW. These changes present mechanisms by which the host and bacteriophage can remain associated without lysis, and the cultures survive extra-intestinal transit. These data provide a basis for understanding a critical link in the ecology of the Campylobacter bacteriophage.

  15. Host adaption to the bacteriophage carrier state of Campylobacter jejuni

    PubMed Central

    Brathwaite, Kelly J.; Siringan, Patcharin; Connerton, Phillippa L.; Connerton, Ian F.

    2015-01-01

    The carrier state of the foodborne pathogen Campylobacter jejuni represents an alternative life cycle whereby virulent bacteriophages can persist in association with host bacteria without commitment to lysogeny. Host bacteria exhibit significant phenotypic changes that improve their ability to survive extra-intestinal environments, but exhibit growth-phase-dependent impairment in motility. We demonstrate that early exponential phase cultures become synchronised with respect to the non-motile phenotype, which corresponds with a reduction in their ability to adhere to and invade intestinal epithelial cells. Comparative transcriptome analyses (RNA-seq) identify changes in gene expression that account for the observed phenotypes: downregulation of stress response genes hrcA, hspR and per and downregulation of the major flagellin flaA with the chemotactic response signalling genes cheV, cheA and cheW. These changes present mechanisms by which the host and bacteriophage can remain associated without lysis, and the cultures survive extra-intestinal transit. These data provide a basis for understanding a critical link in the ecology of the Campylobacter bacteriophage. PMID:26004283

  16. T4 bacteriophage as a phage display platform.

    PubMed

    Gamkrelidze, Mariam; Dąbrowska, Krystyna

    2014-07-01

    Analysis of molecular events in T4-infected Escherichia coli has revealed some of the most important principles of biology, including relationships between structures of genes and their products, virus-induced acquisition of metabolic function, and morphogenesis of complex structures through sequential gene product interaction rather than sequential gene activation. T4 bacteriophages and related strains were applied in the first formulations of many fundamental biological concepts. These include the unambiguous recognition of nucleic acids as the genetic material, the definition of the gene by fine-structure mutation, recombinational and functional analyses, the demonstration that the genetic code is triplet, the discovery of mRNA, the importance of recombination and DNA replications, light-dependent and light-independent DNA repair mechanisms, restriction and modification of DNA, self-splicing of intron/exon arrangement in prokaryotes, translation bypassing and others. Bacteriophage T4 possesses unique features that make it a good tool for a multicomponent vaccine platform. Hoc/Soc-fused antigens can be assembled on the T4 capsid in vitro and in vivo. T4-based phage display combined with affinity chromatography can be applied as a new method for bacteriophage purification. The T4 phage display system can also be used as an attractive approach for cancer therapy. The data show the efficient display of both single and multiple HIV antigens on the phage T4 capsid and offer insights for designing novel particulate HIV or other vaccines that have not been demonstrated by other vector systems. PMID:24828789

  17. MetaPhinder—Identifying Bacteriophage Sequences in Metagenomic Data Sets

    PubMed Central

    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

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

    PubMed

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

    PubMed

    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.

  20. Bacteriophage Typing of Proteus mirabilis, Proteus vulgaris, and Proteus morganii

    PubMed Central

    Schmidt, William C.; Jeffries, Charles D.

    1974-01-01

    A bacteriphage typing scheme for differentiating Proteus isolated from clinical specimens was developed. Twenty-one distinct patterns of lysis were seen when 15 bacteriophages isolated on 8 Proteus mirabilis, 1 P. vulgaris, and 1 P. morganii were used to type 162 of 189 (85.7%) P. mirabilis and P. vulgaris isolates. Seven phages isolated on 3 P. morganii were used to type 13 of 19 (68.4%) P. morganii isolates. Overall, 84.1% of the 208 isolates were lysed by at least 1 phage at routine test dilution (RTD) or 1,000 × RTD. Fifty isolates, retyped several weeks after the initial testing, showed no changes in lytic patterns. The phages retained their titers after storage at 4 C for several months. A computer analysis of the data showed that there was no relationship between the source of the isolate and bacteriophage type. This bacteriophage typing system may provide epidemiological information on strains involved in human infections. PMID:4589141

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

    PubMed

    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

  2. Infrared Camera

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A sensitive infrared camera that observes the blazing plumes from the Space Shuttle or expendable rocket lift-offs is capable of scanning for fires, monitoring the environment and providing medical imaging. The hand-held camera uses highly sensitive arrays in infrared photodetectors known as quantum well infrared photo detectors (QWIPS). QWIPS were developed by the Jet Propulsion Laboratory's Center for Space Microelectronics Technology in partnership with Amber, a Raytheon company. In October 1996, QWIP detectors pointed out hot spots of the destructive fires speeding through Malibu, California. Night vision, early warning systems, navigation, flight control systems, weather monitoring, security and surveillance are among the duties for which the camera is suited. Medical applications are also expected.

  3. 40 CFR 180.1301 - Escherichia coli O157:H7 specific bacteriophages; temporary exemption from the requirement of a...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... bacteriophages; temporary exemption from the requirement of a tolerance. 180.1301 Section 180.1301 Protection of... bacteriophages; temporary exemption from the requirement of a tolerance. A temporary exemption from the requirement of a tolerance is established for residues of lytic bacteriophages that are specific...

  4. Infrared Thermometer

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Diatek Corporation, San Diego, CA and the Jet Propulsion Lab developed the Diatek Model 7000 aural thermometer which weighs only eight ounces, and measures temperature in less than two seconds using infrared astronomy technology to measure the amount of infrared energy emitted by the eardrum (the same way temperature of stars and planets is measured). This method avoids contact with mucous membranes, virtually eliminating the possibility of cross infection, and permits temperature measurement of newborn, critically ill, or incapacitated patients. Diatek Corporation was purchased by Welch Allyn Inc. The Diatek Model 7000 is now marketed as SureTemp.

  5. Infrared Images

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Earth objects emit natural radiation invisible to the unaided human eye, but visible to infrared scanning devices such as the device developed by Inframetrics, Inc. Such devices serve a number of purposes ranging from detection of heat loss in buildings for energy conservation measures, to examining heat output of industrial machinery for trouble shooting and preventive maintenance. Representative of system is Model 525, a small, lightweight field instrument that scans infrared radiation and translates its findings to a TV picture of the temperature pattern in the scene being viewed. An accessory device permits viewing the thermal radiation in color.

  6. Infrared astronomy

    NASA Technical Reports Server (NTRS)

    Gillett, Frederick; Houck, James; Bally, John; Becklin, Eric; Brown, Robert Hamilton; Draine, Bruce; Frogel, Jay; Gatley, Ian; Gehrz, Robert; Hildebrand, Roger

    1991-01-01

    The decade of 1990's presents an opportunity to address fundamental astrophysical issues through observations at IR wavelengths made possible by technological and scientific advances during the last decade. The major elements of recommended program are: the Space Infrared Telescope Facility (SIRTF), the Stratospheric Observatory For Infrared Astronomy (SOFIA) and the IR Optimized 8-m Telescope (IRO), a detector and instrumentation program, the SubMilliMeter Mission (SMMM), the 2 Microns All Sky Survey (2MASS), a sound infrastructure, and technology development programs. Also presented are: perspective, science opportunities, technical overview, project recommendations, future directions, and infrastructure.

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

    SciTech Connect

    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.

  8. [Determination of a Spectrum of Lytic Activity of Bacteriophages by the Method of Acoustic Analysis].

    PubMed

    Guliy, O I; Zaitsev, B D; Kuznetsova, I E; Shikhabudinov, A M; Dykman, L A; Staroverov, S A; Karavaeva, O A; Pavliy, S A; Ignatov, O V

    2015-01-01

    The changes in the electro-acoustic parameters of cell suspension due to the interaction of cells with bacteriophages both in a pure. culture and in the presence of extraneous microflora were investigated. It has been found that the specific changes in the electroacoustic parameters of cell suspension under the action of bacteriophage occur only in microbial cells which are sensitive to the bacteriophage studied. It has been established that a sensor unit allows of distinguishing a situation when the bacterial cells are infected with specific bacteriophages of the control experiments and a situation with no introduction of infection. An approximate criterion of the presence of specific interactions of bacteriophages and cells in suspension was developed. In accordance with this criterion the change in electrical impedance of the sensor unit must not be less than - 1%. In control experiments a standard microbiological technique, plating the cells infected with bacteriophages on solid nutrient medium, was used. For the first time the possibility of using the method of electroacoustic analysis for determination of a spectrum of lytic activity of bacteriophages was shown. The results obtained may be used for development of a new express method for determining the sensitivity to bacteriophages of the microbial cells.

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

    PubMed Central

    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

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

    PubMed Central

    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

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

    NASA Astrophysics Data System (ADS)

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

    PubMed

    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.

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

    PubMed

    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

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

    PubMed

    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

  15. The Genome Sequence of Bacteriophage CPV1 Virulent for Clostridium perfringens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Application of bacteriophages and their lytic enzymes to control Clostridium perfringens is one potential approach to reduce the pathogen on poultry farms and in poultry-processing facilities. Bacteriophages lytic for C. perfringens were isolated from sewage, feces and broiler intestinal contents. P...

  16. [Generalized transduction of plasmid pKM101 by temperate bacteriophage ZF40 of Erwinia carotovora].

    PubMed

    Panshchina, A I; Tovkach, F I

    2007-01-01

    It was shown that temperate bacteriophage ZF40 of Erwinia carotovora can perform generalized transduction of plasmid pKM 101. The antibiotic-resistance marker transfer is coordinated with the fact of cyclic permutation of the phage genom. The presented results create preconditions for further use of bacteriophage ZF40 as a convenient instrument for genetic study of E. carotovora.

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

    PubMed

    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).

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

    PubMed

    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).

  19. Infrared telescope

    NASA Technical Reports Server (NTRS)

    Karr, G. R.; Hendricks, J. B.

    1985-01-01

    The development of the Infrared Telescope for Spacelab 2 is discussed. The design, development, and testing required to interface a stationary superfluid helium dewar with a scanning cryostate capable of operating in the zero-g environment in the space shuttle bay is described.

  20. Infrared Thermometers

    ERIC Educational Resources Information Center

    Schaefers, John

    2006-01-01

    An infrared (IR) thermometer lab offers the opportunity to give science students a chance to measure surface temperatures, utilizing off-the-shelf technology. Potential areas of study include astronomy (exoplanets), electromagnetic spectrum, chemistry, evaporation rates, anatomy, crystal formation, and water or liquids. This article presents one…

  1. Cloning, expression, and sequence determination of a bacteriophage fragment encoding bacteriophage resistance in Lactococcus lactis.

    PubMed

    Hill, C; Miller, L A; Klaenhammer, T R

    1990-11-01

    A number of host-encoded phage resistance mechanisms have been described in lactococci. However, the phage genome has not been exploited as a source of additional resistance determinants. A 4.5-kb BamHI-HindIII fragment of phage nck202.50 (phi 50) was subcloned in streptococcus-Escherichia coli shuttle plasmid pSA3 and introduced into Lactococcus lactis NCK203 and MG1363 by protoplast transformation. This cloned phage fragment directed a bacteriophage resistance phenotype designated Per (phage-encoded resistance). Both phi 50 and a distantly related phage, nck202.48 (phi 48), formed small plaques on strain NCK213 at a slightly reduced efficiency of plaquing on the Per+ host. The per locus was further reduced to a 1.4-kb fragment through in vitro deletion analysis. The 1.4-kb fragment was sequenced, and the Per phenotype was found to be associated with a ca. 500-bp region rich in direct and inverted repeats. We present evidence that the Per region contains a phage origin of replication which, in trans, may interfere with phage replication by titration of DNA polymerase or other essential replication factors. It was demonstrated that the Per+ phenotype is not a result of reduced adsorption or action of a restriction and modification system. Per+ activity was not detected against six independent phages which were previously shown to be sensitive to the Hsp+ mechanism. The mutually exclusive resistance mechanisms could be combined to confer resistance to both types of phages (Hsp resistant and Per resistant) in a single host. This is the first description in lactococci of a phage resistance phenotype, other than superinfection immunity, originating from a lactococcal phage genome.

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

    PubMed

    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

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

    PubMed

    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.

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

    PubMed

    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. Infrared floodlight

    DOEpatents

    Levin, Robert E.; English, George J.

    1986-08-05

    An infrared floodlight assembly designed particularly for security purposes and including a heat-conducting housing, a lens secured to the housing to provide a closure therefor, and a floodlight located within (and surrounded by) the housing. The floodlight combines the use of a tungsten halogen light source and dichroic hot and cold mirrors for directing substantially only infrared radiation toward the assembly's forward lens. Visible radiation is absorbed by the housing's interior wall(s) and, optionally, by a filter located between the floodlight and lens. An optional means may be used within the floodlight to reflect all forward radiation back toward the paraboloidal hot mirror or, alternatively, to reflect only visible radiation in this direction. The dichroic hot and cold mirrors preferably each comprise a glass substrate having multiple layers of titanium dioxide and silicon dioxide thereon.

  6. Infrared backscattering

    NASA Technical Reports Server (NTRS)

    Bohren, Craig F.; Nevitt, Timothy J.; Singham, Shermila Brito

    1989-01-01

    All particles in the atmosphere are not spherical. Moreover, the scattering properties of randomly oriented nonspherical particles are not equivalent to those of spherical particles no matter how the term equivalent is defined. This is especially true for scattering in the backward direction and at the infrared wavelengths at which some atmospheric particles have strong absorption bands. Thus calculations based on Mie theory of infrared backscattering by dry or insoluble atmospheric particles are suspect. To support this assertion, it was noted that peaks in laboratory-measured infrared backscattering spectra show appreciable shifts compared with those calculated using Mie theory. One example is ammonium sulfate. Some success was had in modeling backscattering spectra of ammonium sulfate particles using a simple statistical theory called the continuous distribution of ellipsoids (CDE) theory. In this theory, the scattering properties of an ensemble are calculated. Recently a modified version of this theory was applied to measured spectra of scattering by kaolin particles. The particles were platelike, so the probability distribution of ellipsoidal shapes was chosen to reflect this. As with ammonium sulfate, the wavelength of measured peak backscattering is shifted longward of that predicted by Mie theory.

  7. Infrared retina

    DOEpatents

    Krishna, Sanjay; Hayat, Majeed M.; Tyo, J. Scott; Jang, Woo-Yong

    2011-12-06

    Exemplary embodiments provide an infrared (IR) retinal system and method for making and using the IR retinal system. The IR retinal system can include adaptive sensor elements, whose properties including, e.g., spectral response, signal-to-noise ratio, polarization, or amplitude can be tailored at pixel level by changing the applied bias voltage across the detector. "Color" imagery can be obtained from the IR retinal system by using a single focal plane array. The IR sensor elements can be spectrally, spatially and temporally adaptive using quantum-confined transitions in nanoscale quantum dots. The IR sensor elements can be used as building blocks of an infrared retina, similar to cones of human retina, and can be designed to work in the long-wave infrared portion of the electromagnetic spectrum ranging from about 8 .mu.m to about 12 .mu.m as well as the mid-wave portion ranging from about 3 .mu.m to about 5 .mu.m.

  8. Bacteriophage-Derived Vectors for Targeted Cancer Gene Therapy

    PubMed Central

    Pranjol, Md Zahidul Islam; Hajitou, Amin

    2015-01-01

    Cancer gene therapy expanded and reached its pinnacle in research in the last decade. Both viral and non-viral vectors have entered clinical trials, and significant successes have been achieved. However, a systemic administration of a vector, illustrating safe, efficient, and targeted gene delivery to solid tumors has proven to be a major challenge. In this review, we summarize the current progress and challenges in the targeted gene therapy of cancer. Moreover, we highlight the recent developments of bacteriophage-derived vectors and their contributions in targeting cancer with therapeutic genes following systemic administration. PMID:25606974

  9. Recovery of temperate Desulfovibrio vulgaris bacteriophage on anovel host strain

    SciTech Connect

    Walker, C.B.; Stolyar, S.S.; Pinel, N.; Yen, H.C.; He, Z.; Zhou,J.; Wall, J.D.; Stahl, D.A.

    2007-04-02

    A novel sulfate-reducing bacterium (strain DePue) closelyrelated to Desulfovibrio vulgaris ssp. vulgaris strain Hildenborough wasisolated from the sediment of a heavy-metal impacted lake usingestablished techniques. Although few physiological differences betweenstrains DePue and Hildenborough were observed, pulsed-field gelelectrophoresis (PFGE) revealed a significant genome reduction in strainDePue. Comparative whole-genome microarray and PCR analyses demonstratedthat the absence of genes annotated in the Hildenborough genome as phageor phage-related contributed to the significant genome reduction instrain DePue. Two morphotypically distinct temperate bacteriophage fromstrain Hildenborough were recovered using strain DePue as a host forplaque isolation.

  10. Morphology manipulation of M13 bacteriophage template for nanostructure assembly

    NASA Astrophysics Data System (ADS)

    Ngo-Duc, Tam-Triet; Zaman, Mohammed S.; Moon, Chung-Hee; Haberer, Elaine D.

    2014-08-01

    A gold-binding M13 bacteriophage was used as a model system to explore templating of inorganic material on geometrically transformed viruses . Gold-binding filamentous phage were converted to spheroid form with a short chloroform treatment, and the resulting morphology was investigated with electron microscopy. Binding studies revealed that spheroid-shaped gold-binding phage preserved its affinity for gold. Spheroids adhered to a planar substrate assembled clusters or rings of gold nanoparticles. This gold-binding phage served as a demonstration of a highly shape-modifiable viral-template for inorganic materials.

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

    PubMed

    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.

  12. The role of temperate bacteriophages in bacterial infection.

    PubMed

    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.

  13. Making Bacteriophage DNA into a Movie for Panspermia

    NASA Astrophysics Data System (ADS)

    Norris, Victor; Grondin, Yohann

    2011-12-01

    To satisfy the urge to communicate with another species, distant from our own in space or time, we explore the advantages of using the nucleic acid within a bacteriophage to encode a message and suggest how this might be achieved. We list some of the technical difficulties that need to be overcome and describe some of the advantages as a message-bearing medium that phage such as T5 possess. These advantages include those of stability in certain environments and DNA packed in a regular way within the capsid. We raise questions that would need to be answered and that would require close collaborations across the disciplines.

  14. The effect of alpha particles on bacteriophage T4Br+.

    PubMed

    Leont'eva, G A; Akoev, I G; Grigor'ev, A E

    1983-01-01

    It is generally accepted that heavy charged particles play an important part in generating the secondary flux of nuclear particles formed by the interaction of space hadrons with nuclei. It is assumed that these particles are responsible for the high biological efficiency of space hadrons in causing cellular damage by their strong interactions. To examine this assumption we investigated the effects of 5.3 MeV alpha particles on bacteriophage T4. This energy provides a LET value of 88.6 KeV/micrometer lying in the range of the highest biological efficiency. PMID:11542756

  15. Alkali lability of bacteriophage phi W-14 DNA.

    PubMed

    Lewis, H A; Miller, R C; Stone, J C; Warren, R A

    1975-12-01

    The molecular weight of bacteriophage phi W-14 DNA, determined by velocity sedimentation in neutral sucrose gradients, was 92 +/- 6 X 10(6). The DNA showed marked fragmentation in alkaline sucrose gradients. This fragmentation was not a consequence of preexisting single-strand interruptions in the DNA, since thermal denaturation of DNA yielded intact single strands. The alpha-putrescinylthymine groups in phi W-14 DNA appeared to be labile; some, or parts of some, of these groups were cleaved from the DNA in alkali. PMID:1202241

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

    PubMed Central

    De Paepe, Marianne; Leclerc, Marion; Tinsley, Colin R.; Petit, Marie-Agnès

    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 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. PMID:24734220

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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. PMID:26628254

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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

  4. Complete genome sequence of Pseudomonas aeruginosa lytic bacteriophage PA1O which resembles temperate bacteriophage D3112.

    PubMed

    Kim, Shukho; Rahman, Marzia; Kim, Jungmin

    2012-03-01

    A novel Pseudomonas aeruginosa lytic bacteriophage (phage), PA1Ø, was isolated, and its genome was sequenced completely. This phage is able to lyse not only P. aeruginosa but also Staphylococcus aureus. Genome analysis of PA1Ø showed that it is similar to a P. aeruginosa temperate phage, D3112, with the exception of the absence of a c repressor-encoding gene, which is known to play a critical role in the maintenance of the lysogenic state of D3112 in P. aeruginosa. PMID:22354942

  5. Far infrared supplement: Catalog of infrared observations

    NASA Technical Reports Server (NTRS)

    Gezari, D. Y.; Schmitz, M.; Mead, J. M.

    1984-01-01

    The Far Infrared Supplement: catalog of infrared observations summarizes all infrared astronomical observations at far infrared wavelengths published in the scientific literature between 1965 and 1982. The Supplement list contains 25% of the observations in the full catalog of infrared observations (C10), and essentially eliminates most visible stars from the listings. The Supplement is more compact than the main Catalog (it does not contain the bibliography and position index of the C10), and is intended for easy reference during astronomical observations.

  6. Complete genome sequence of Salmonella enterica serovar typhimurium bacteriophage SPN1S.

    PubMed

    Shin, Hakdong; Lee, Ju-Hoon; Lim, Jeong-A; Kim, Hyeryen; Ryu, Sangryeol

    2012-01-01

    To understand the interaction between the host of pathogenic Salmonella enterica serovar Typhimurium and its bacteriophage, we isolated the bacteriophage SPN1S. It is a lysogenic phage in the Podoviridae family and uses the O-antigen of lipopolysaccharides (LPS) as a host receptor. Comparative genomic analysis of phage SPN1S and the S. enterica serovar Anatum-specific phage ε15 revealed different host specificities, probably due to the low homology of host specificity-related genes. Here we report the complete circular genome sequence of S. Typhimurium-specific bacteriophage SPN1S and show the results of our analysis. PMID:22205721

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

    PubMed

    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

  8. Complete Genome Sequences of Lytic Bacteriophages of Xanthomonas arboricola pv. Juglandis

    PubMed Central

    Vasquez, Ignacio; Santos, Leonardo; Segovia, Cristopher; Ayala, Manuel; Alvarado, Romina; Nuñez, Pablo

    2016-01-01

    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. PMID:27257210

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

    PubMed

    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.

  10. Isolation and characterization of bacteriophages infecting Staphylococcus epidermidis.

    PubMed

    Gutiérrez, Diana; Martínez, Beatriz; Rodríguez, Ana; García, Pilar

    2010-12-01

    Bacteriophages infecting Staphylococcus epidermidis were isolated by mitomycin C induction. Three distinct phages (vB_SepiS-phiIPLA5, vB_SepiS-phiIPLA6, and vB_SepiS-phiIPLA7)-defined by plaque morphology, structure, virion proteins pattern, DNA restriction bands, and host range-were obtained. One-step growth curves of bacteriophages under optimal growth conditions for S. epidermidis F12 revealed eclipse and latent periods of 5-10 and 10-15 min, respectively, with burst sizes of about 5 to 30 PFU per infected cell. Transmission electron microscopy revealed that the phages were of similar size and belonged to the Siphoviridae family. Phage phi-IPLA7 had the broadest host range infecting 21 out of 65 S. epidermidis isolates. Phage phi-IPLA5 seemed to be a virulent phage probably derived from phi-IPLA6. Phages phi-IPLA5 and phi-IPLA7 exhibited increasing plaques surrounded by a halo that could be indicative of a polysaccharide depolymerase activity. Viable counts, determined during the infection of S. epidermidis F12, confirmed that phi-IPLA5 had a potent lytic capability and reduced S. epidermidis population by 5.67 log units in 8 h of incubation; in the presence of the mixture of phi-IPLA6 and phi-IPLA7, however, a reduction of 2.27 log units was detected.

  11. Alteration of bacteriophage attachment capacity by near-UV irradiation.

    PubMed Central

    Hartman, P S; Einsenstark, A

    1982-01-01

    Near-UV (NUV) (300 to 400 nm) and far-UV (FUV) (254 nm) radiations damage bacteriophage by different mechanisms. Host cell reactivation, Weigle reactivation, and multiplicity reactivation were observed upon FUV, but not upon NUV irradiation. Also, the number of his+ recombinants increased with P22 bacteriophage transduction in Salmonella typhimurium after FUV, but not after NUV irradiation. This loss of reactivation and recombination after NUV irradiation was not necessarily due to host incapability to repair phage damage. Instead, the phage genome failed to enter the host cell after NUV irradiation. In the case of NUV-irradiated T7 phage, this was determined by genetic crosses with amber mutants, which demonstrated that either "all" or "none" of a T7 genome entered the Escherichia coli cell after NUV treatment. Further studies with radioactively labeled phage indicated that irradiated phage failed to adsorb to host cells. This damage by NUV was compared with the protein-DNA cross-link observed previously, when phage particles were irradiated with NUV in the presence of H2O2. H2O2 (in nonlethal concentration) acts synergistically with NUV so that equivalent phage inactivation is achieved by much lower irradiation doses. PMID:7050407

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

    PubMed

    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. PMID:22381912

  13. Within-host competition determines reproductive success of temperate bacteriophages.

    PubMed

    Refardt, Dominik

    2011-09-01

    Within-host competition between parasites is frequently invoked as a major force for parasite evolution, yet quantitative studies on its extent in an organismal group are lacking. Temperate bacteriophages are diverse and abundant parasites of bacteria, distinguished by their ability to enter a facultative dormant state in their host. Bacteria can accumulate multiple phages that may eventually abandon dormancy in response to host stress. Host resources are then converted into phage particles, whose release requires cell death. To study within-host competition between phages, I used the bacterium Escherichia coli and 11 lambdoid phages to construct single and double lysogens. Lysogenic bacterial cultures were then induced and time to host cell lysis and productivity of phages was measured. In double lysogens, this revealed strong competitive interactions as in all cases productivity of at least one phage declined. The outcome of within-host competition was often asymmetrical, and phages were found to vary hierarchically in within-host competitive ability. In double infections, the phage with the shorter lysis time determined the timing of cell lysis, which was associated with a competitive advantage when time differences were large. The results emphasize that within-host competition greatly affects phage fitness and that multiple infections should be considered an integral part of bacteriophage ecology. PMID:21412345

  14. Bacteriophages and indicator bacteria in human and animal faeces.

    PubMed

    Havelaar, A H; Furuse, K; Hogeboom, W M

    1986-03-01

    In an attempt to explain the presence of F-specific (RNA) bacteriophages in waste-water, faecal material from humans and a variety of animals was examined. The phages were detected in appreciable numbers only in faeces from pigs, broiler chickens, sheep and calves but not from dogs, cows, horses and humans. Parallel examinations for somatic coliphages, thermotolerant coliforms, faecal streptococci and spores of sulphite-reducing clostridia revealed the consistent presence of these organisms in all types of samples, albeit in variable numbers. The number of F-specific bacteriophages was related to the total number of somatic coliphages, but phage counts were unrelated to bacterial counts. F-specific RNA phages were grouped by serotyping and all animal isolates were found to belong to either group I (MS2 subtype) or IV (four different subtypes). Among the group IV isolates, most belonged to well-known subtypes SP (24 isolates) or FI (18 isolates) but five isolates were related to phage ID2 and one isolate was a new subtype. In contrast with animal isolates, 19 isolates from hospital wastewater belonged to serogroups II or III.

  15. [Permeability to phi chi 174 bacteriophages in polyolephin membrane condoms].

    PubMed

    Sierra, Oscar Eugenio; Gaona de Hernández, María Antonia; Rey, Gloria Janneth

    2005-12-01

    Membranes used for the manufacture of condoms eventually can develop tiny pores, thereby decreasing dramatically their effectiveness as a physical barrier against the transmission of infectious agents. A technique was designed that was based on the ability of bacteriophage viruses to trespass membranes and to infect certain bacteria species, and then developing lysis plaques in the colonies of the host bacteria. The effectiveness of 60 polyolefin condoms in preventing the diffusion of the bacteriophage phi chi 174(ATCC13706-B1), 27 nm diameter, was compared to 20 latex condoms. Physiological conditions such as pressure, pH, superficial tension, length, time of exposure and viral titre were simulated. A pressurization system was designed, in which compressed air was injected simultaneously to ten condoms. Four of the 60 polyolefin condoms and one of the 20 latex condoms were permeable to the virus. Therefore, at least 93% of the condoms evaluated were able to contain the virus. The difference in permeability between the two types of membranes was not statistically significant (P = 0.79).

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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. Characterization of recombinant bacteriophages containing mosquito ribosomal RNA genes

    SciTech Connect

    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.

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

    PubMed Central

    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

  20. Restriction of bacteriophage plaque formation in Streptomyces spp.

    PubMed

    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. REDOR NMR Characterization of DNA Packaging in Bacteriophage T4

    PubMed Central

    Yu, Tsyr-Yan; Schaefer, Jacob

    2008-01-01

    Bacteriophage T4 is a large-tailed E. coli virus whose capsid is 120 × 86 nm. ATP-driven DNA packaging of the T4 capsid results in the loading of a 171-kb genome in less than 5 minutes during viral infection. We have isolated 50-mg quantities of uniform 15N and [ε-15N]lysine-labeled bacteriophage T4. We have also introduced 15NH4+ into filled, unlabeled capsids from synthetic medium by exchange. We have examined lyo- and cryoprotected lyophilized T4 using 15N{31P} and 31P{15N} rotational-echo double resonance. The results of these experiments have shown that: (i) packaged DNA is in an unperturbed duplex B-form conformation; (ii) the DNA phosphate negative charge is balanced by lysyl amines (3.2%), polyamines (5.8%), and monovalent cations (40%); and (iii) 11% of lysyl amines, 40% of –NH2 groups of polyamines, and 80% of monovalent cations within the lyophilized T4 capsid, are involved in the DNA charge balance. The NMR evidence suggests that DNA enters the T4 capsid in a charge-unbalanced state. We propose that electrostatic interactions may provide free energy to supplement the nanomotor-driven T4 DNA packaging. PMID:18703073

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

    PubMed

    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

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

    PubMed

    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.

  4. The adaptive potential of hybridization demonstrated with bacteriophages

    PubMed Central

    Sackman, Andrew M.; Rokyta, Darin R.

    2013-01-01

    The success or failure of hybrids and the factors that determine their fitness have ecological, evolutionary, medical, and economic implications. Hybrid fitness is a major determinant of the size of hybrid zones and the maintenance of related species with overlapping ranges. It also influences the evolution of emerging pathogens and the success of economically important crop species experimentally hybridized in search of strains with increased yields or disease resistance. Hybrid fitness may largely be determined by the pervasiveness of epistasis in the genome, as epistasis is known to debilitate hybrids through disrupted inter- and intragenic interactions. We identified two bacteriophages isolated from their natural environment, one the result of a past hybridization event involving an ancestor of the other phage and a third, unknown phage. By performing a reciprocal cross of the affected region of the genome, consisting of a single complete gene, we both approximately recreated and reversed this original hybridization event in two chimeric bacteriophage genomes. Subsequent adaptation of the hybrid phages allowed for the recovery of fitness losses incurred by the hybrid genotypes. Furthermore, adaptation led to the ascension of a substantially higher and previously inaccessible adaptive peak. We show that by allowing genotypes to take large leaps across the adaptive landscape rather than single mutational steps, hybridization can lead to huge long-term fitness gains in spite of short-term costs resulting from disrupted epistatic interactions, demonstrating that the success or failure of hybrids may be determined not by their initial fitness, but rather by their adaptive potential. PMID:24078088

  5. Infrared Heaters

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The heating units shown in the accompanying photos are Panelbloc infrared heaters, energy savers which burn little fuel in relation to their effective heat output. Produced by Bettcher Manufacturing Corporation, Cleveland, Ohio, Panelblocs are applicable to industrial or other facilities which have ceilings more than 12 feet high, such as those pictured: at left the Bare Hills Tennis Club, Baltimore, Maryland and at right, CVA Lincoln- Mercury, Gaithersburg, Maryland. The heaters are mounted high above the floor and they radiate infrared energy downward. Panelblocs do not waste energy by warming the surrounding air. Instead, they beam invisible heat rays directly to objects which absorb the radiation- people, floors, machinery and other plant equipment. All these objects in turn re-radiate the energy to the air. A key element in the Panelbloc design is a coating applied to the aluminized steel outer surface of the heater. This coating must be corrosion resistant at high temperatures and it must have high "emissivity"-the ability of a surface to emit radiant energy. The Bettcher company formerly used a porcelain coating, but it caused a production problem. Bettcher did not have the capability to apply the material in its own plant, so the heaters had to be shipped out of state for porcelainizing, which entailed extra cost. Bettcher sought a coating which could meet the specifications yet be applied in its own facilities. The company asked The Knowledge Availability Systems Center, Pittsburgh, Pennsylvania, a NASA Industrial Applications Center (IAC), for a search of NASA's files

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

    PubMed

    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.

  7. Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Wehling, Randy L.

    Infrared (IR) spectroscopy refers to measurement of the absorption of different frequencies of IR radiation by foods or other solids, liquids, or gases. IR spectroscopy began in 1800 with an experiment by Herschel. When he used a prism to create a spectrum from white light and placed a thermometer at a point just beyond the red region of the spectrum, he noted an increase in temperature. This was the first observation of the effects of IR radiation. By the 1940s, IR spectroscopy had become an important tool used by chemists to identify functional groups in organic compounds. In the 1970s, commercial near-IR reflectance instruments were introduced that provided rapid quantitative determinations of moisture, protein, and fat in cereal grains and other foods. Today, IR spectroscopy is used widely in the food industry for both qualitative and quantitative analysis of ingredients and finished foods.

  8. Far infrared supplement: Catalog of infrared observations

    NASA Technical Reports Server (NTRS)

    Gezari, D. Y.; Schmitz, M.; Mead, J. M.

    1982-01-01

    The development of a new generation of orbital, airborne and ground-based infrared astronomical observatory facilities, including the infrared astronomical satellite (IRAS), the cosmic background explorer (COBE), the NASA Kuiper airborne observatory, and the NASA infrared telescope facility, intensified the need for a comprehensive, machine-readable data base and catalog of current infrared astronomical observations. The Infrared Astronomical Data Base and its principal data product, this catalog, comprise a machine-readable library of infrared (1 micrometer to 1000 micrometers) astronomical observations published in the scientific literature since 1965.

  9. The effect of tryptophol on the bacteriophage infection in high-temperature environment.

    PubMed

    Jin, Min; Xu, Chenxi; Zhang, Xiaobo

    2015-10-01

    Small metabolites can participate in the virus-host interactions in eukaryotes. However, little is known about roles of metabolites in the interactions between bacteria and bacteriophages. In this study, the metabolomic profilings of bacteriophage GVE2-infected and virus-free Geobacillus sp. E263, a thermophilic bacterium isolated from a deep-sea hydrothermal vent, were characterized. The results showed that metabolites tryptophol, adenine, and hydroxybenzylalcohol were significantly elevated in Geobacillus sp. E263 in response to the GVE2 infection. Furthermore, our data indicated that tryptophol was involved in the bacteriophage infection. Tryptophol could inhibit the infection/replication of GVE2 by interacting with the host's Clp protease. Therefore, our study revealed novel aspects of metabolites during the bacteriophage infection in high-temperature environment. PMID:25994257

  10. The effect of tryptophol on the bacteriophage infection in high-temperature environment.

    PubMed

    Jin, Min; Xu, Chenxi; Zhang, Xiaobo

    2015-10-01

    Small metabolites can participate in the virus-host interactions in eukaryotes. However, little is known about roles of metabolites in the interactions between bacteria and bacteriophages. In this study, the metabolomic profilings of bacteriophage GVE2-infected and virus-free Geobacillus sp. E263, a thermophilic bacterium isolated from a deep-sea hydrothermal vent, were characterized. The results showed that metabolites tryptophol, adenine, and hydroxybenzylalcohol were significantly elevated in Geobacillus sp. E263 in response to the GVE2 infection. Furthermore, our data indicated that tryptophol was involved in the bacteriophage infection. Tryptophol could inhibit the infection/replication of GVE2 by interacting with the host's Clp protease. Therefore, our study revealed novel aspects of metabolites during the bacteriophage infection in high-temperature environment.

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

    PubMed

    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.

  12. M13 Bacteriophage-Based Self-Assembly Structures and Their Functional Capabilities

    PubMed Central

    Moon, Jong-Sik; Kim, Won-Geun; Kim, Chuntae; Park, Geun-Tae; Heo, Jeong; Yoo, So Y; Oh, Jin-Woo

    2015-01-01

    Controlling the assembly of basic structural building blocks in a systematic and orderly fashion is an emerging issue in various areas of science and engineering such as physics, chemistry, material science, biological engineering, and electrical engineering. The self-assembly technique, among many other kinds of ordering techniques, has several unique advantages and the M13 bacteriophage can be utilized as part of this technique. The M13 bacteriophage (Phage) can easily be modified genetically and chemically to demonstrate specific functions. This allows for its use as a template to determine the homogeneous distribution and percolated network structures of inorganic nanostructures under ambient conditions. Inexpensive and environmentally friendly synthesis can be achieved by using the M13 bacteriophage as a novel functional building block. Here, we discuss recent advances in the application of M13 bacteriophage self-assembly structures and the future of this technology. PMID:26146494

  13. Genome Sequences of Two Bacillus cereus Group Bacteriophages, Eyuki and AvesoBmore

    PubMed Central

    2015-01-01

    The genomes of two double-stranded DNA (dsDNA) bacteriophages isolated on Bacillus thuringiensis show similarity to previously sequenced phages and provide evidence of the mosaicism of phage genomes. PMID:26472840

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

    PubMed Central

    Kot, Witold

    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. PMID:26184932

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

    PubMed

    Jorquera, Denisse; Galarce, Nicolás; Borie, Consuelo

    2015-12-01

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

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

    PubMed

    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.

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

    PubMed

    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.

  18. The gene for type A streptococcal exotoxin (erythrogenic toxin) is located in bacteriophage T12.

    PubMed Central

    Weeks, C R; Ferretti, J J

    1984-01-01

    The infection of Streptococcus pyogenes T25(3) with the temperate bacteriophage T12 results in the conversion of the nontoxigenic strain to type A streptococcal exotoxin (erythrogenic toxin) production. Although previous research has established that integration of the bacteriophage genome into the host chromosome is not essential for exotoxin production, the location of the gene on the bacteriophage or bacterial chromosome had not been determined. In the present investigation, recombinant DNA techniques were used to determine whether the gene specifying type A streptococcal exotoxin (speA) production is located on the bacteriophage chromosome. Bacteriophage T12 was obtained from S. pyogenes T25(3)(T12) by induction with mitomycin C, and after isolation of bacteriophage DNA by phenol-chloroform extraction, the DNA was digested with restriction enzymes and ligated with Escherichia coli plasmid pHP34 or the Streptococcus-E. coli shuttle vector pSA3. Transformation of E. coli HB101 with the recombinant molecules allowed selection of E. coli clones containing bacteriophage T12 genes. Immunological assays with specific antibody revealed the presence of type A streptococcal exotoxin in sonicates of E. coli transformants. Subcloning experiments localized the speA gene to a 1.7-kilobase segment of the bacteriophage T12 genome flanked by SalI and HindIII sites. Introduction of the pSA3 vector containing the speA gene into Streptococcus sanguis (Challis) resulted in transformants that secreted the type A exotoxin. Immunological analysis showed that the type A streptococcal exotoxin produced by E. coli and S. sanguis transformants was identical to the type A exotoxin produced by S. pyogenes T25(3)(T12). Southern blot hybridizations with the cloned fragment confirmed its presence in the bacteriophage T12 genome and its absence in the T25(3) nonlysogen. Therefore, the gene for type A streptococcal exotoxin is located in the bacteriophage genome, and conversion of S. pyogenes T

  19. Bacteriophage SPP1 Tail Tube Protein Self-assembles into β-Structure-rich Tubes*

    PubMed Central

    Langlois, Chantal; Ramboarina, Stéphanie; Cukkemane, Abhishek; Auzat, Isabelle; Chagot, Benjamin; Gilquin, Bernard; Ignatiou, Athanasios; Petitpas, Isabelle; Kasotakis, Emmanouil; Paternostre, Maïté; White, Helen E.; Orlova, Elena V.; Baldus, Marc; Tavares, Paulo; Zinn-Justin, Sophie

    2015-01-01

    The majority of known bacteriophages have long tails that serve for bacterial target recognition and viral DNA delivery into the host. These structures form a tube from the viral capsid to the bacterial cell. The tube is formed primarily by a helical array of tail tube protein (TTP) subunits. In phages with a contractile tail, the TTP tube is surrounded by a sheath structure. Here, we report the first evidence that a phage TTP, gp17.1 of siphophage SPP1, self-assembles into long tubes in the absence of other viral proteins. gp17.1 does not exhibit a stable globular structure when monomeric in solution, even if it was confidently predicted to adopt the β-sandwich fold of phage λ TTP. However, Fourier transform infrared and nuclear magnetic resonance spectroscopy analyses showed that its β-sheet content increases significantly during tube assembly, suggesting that gp17.1 acquires a stable β-sandwich fold only after self-assembly. EM analyses revealed that the tube is formed by hexameric rings stacked helicoidally with the same organization and helical parameters found for the tail of SPP1 virions. These parameters were used to build a pseudo-atomic model of the TTP tube. The large loop spanning residues 40–56 is located on the inner surface of the tube, at the interface between adjacent monomers and hexamers. In line with our structural predictions, deletion of this loop hinders gp17.1 tube assembly in vitro and interferes with SPP1 tail assembly during phage particle morphogenesis in bacteria. PMID:25525268

  20. Complete genome sequence of Bp7, an Escherichia coli bacteriophage with a wide host range.

    PubMed

    Zhang, Can; Liu, Wenhua; Ren, Huiying

    2012-12-01

    Chicken colibacillosis is caused by some pathogenic Escherichia coli strains. Thirty-five pathogenic antibiotic-resistant E. coli strains were used in the host range detection of bacteriophage Bp7. The phage showed a wide range of E. coli hosts (46%). The complete genome of bacteriophage Bp7 was sequenced, assembled, and analyzed. The results revealed a linear double-stranded DNA sequence of 168,066 bp harboring 791 open reading frames. The major findings from its annotation are described.

  1. The role of regulated clinical trials in the development of bacteriophage therapeutics.

    PubMed

    Parracho, Helena Mrt; Burrowes, Ben H; Enright, Mark C; McConville, Malcolm L; Harper, David R

    2012-01-01

    Antibiotic resistance is now recognized as a major, global threat to human health and the need for the development of novel antibacterial therapies has become urgent. Lytic bacteriophages (phages) targeting individual bacterial pathogens have therapeutic potential as an alternative or adjunct to antibiotic use. Bacteriophage therapy has been used for decades, but clinical trials in this field are rare, leaving many questions unanswered as to its effectiveness for many infectious diseases. As a consequence bacteriophage therapy is not used or accepted in most parts of the world. The increasing need for new antimicrobial therapies is driving the development of bacteriophage therapies for a number of diseases but these require the successful completion of large-scale clinical trials in accordance with US FDA or European EMA guidelines. Bacteriophages are considered as biological agents by regulatory authorities and they are managed by biological medicinal products guidelines for European trials and guidelines of the division of vaccines and related product applications in the USA. Bacteriophage therapy is typically an 'active' treatment requiring multiplication in the bacterial host and therefore the factors that govern its success are different from those of conventional antibiotics. From the pharmacokinetic and pharmacodynamic points of view, time of treatment, dosage depending on the site of infection and the composition of the bacteriophage formulation (single vs multiple strains) need careful consideration when designing clinical trials. Scientific evidence regarding inflammatory effects, potential for gene transfer and phage resistance, need to be evaluated through such trials. However purity, stability and sterility of preparations for human use can be addressed through Good Manufacturing Practises to reduce many potential safety concerns. In this review we discuss the potential for the development of bacteriophage therapy in the context of critical aspects of

  2. Silk route to the acceptance and re-implementation of bacteriophage therapy.

    PubMed

    2016-05-01

    This multidisciplinary expert panel opinion on bacteriophage therapy has been written in the context of a society that is confronted with an ever-increasing number of antibiotic resistant bacteria. To avoid the return to a pre-antibiotic era, alternative treatments are urgently needed. The authors aim to contribute to the opinion formation of relevant stakeholders on how to potentially develop an infrastructure and legislation that paves the way for the acceptance and re-implementation of bacteriophage therapy. PMID:27008250

  3. Use of bacteriophage for biological control of Salmonella Enteritidis infection in chicken.

    PubMed

    Lim, Tae-Hyun; Kim, Myung-Seob; Lee, Dong-Hun; Lee, Yu-Na; Park, Jae-Keun; Youn, Ha-Na; Lee, Hyun-Jeong; Yang, Si-Yong; Cho, Young-Wook; Lee, Joong-Bok; Park, Seung-Yong; Choi, In-Soo; Song, Chang-Seon

    2012-12-01

    Bacteriophage ΦCJ07 with broad host ranges for Salmonella strains isolated from sewage effluent were used to reduce Salmonella Enteritidis (SE) infection in chickens. One-day-old chicks challenged with 5×10(7) colony-forming units/bird of SE were cohabitated with contact chicks and treated with three concentrations (10(5), 10(7) and 10(9) plaque forming units (PFU)/g) of bacteriophage prepared as a feed additive for 21days after challenge. Salmonella in the intestine was quantified and environmental contamination level was examined at 1, 2 and 3weeks after challenge. All treatments reduced intestinal SE colonization in challenged and contact chickens and reduced the environmental contamination level, but the reductions produced by 10(7) and 10(9)PFU/g of bacteriophage were significant (P<0.05) as compared with untreated controls. In addition, seven out of 10 (70%) contact chickens treated with 10(9)PFU/g of bacteriophage had no detectable intestinal Salmonella at 3weeks after treatment, suggesting that bacteriophage therapy significantly prevented the horizontal transmission of SE. These results provide important insights into preventive and control strategies against SE infection in poultry and indicate that the use of bacteriophage could reduce the incidence of Salmonella food poisoning. PMID:22795674

  4. Free-range layer chickens as a source of Campylobacter bacteriophage.

    PubMed

    Loc Carrillo, Catherine M; Connerton, Phillippa L; Pearson, Tom; Connerton, Ian F

    2007-10-01

    Bacteriophage specific for Campylobacter were isolated from chicken excreta collected from established free-range layer breed stock. Bacteriophage were either propagated on a Campylobacter jejuni host with broad susceptibility to bacteriophage (NCTC 12662) or on Campylobacter isolates from the same samples. Campylobacters were confirmed as being C. jejuni and or C. coli, using a combination of standard biochemical tests and PCR analysis with genus and species specific primers. The bacteriophage displayed differential patterns of susceptibility against reference NCTC strains and contemporary C. jejuni /C. coli isolates from chicken excreta. Electron microscopy demonstrated that the phage possessed icosahedral heads and rigid contractile tails. Pulsed-field gel electrophoresis revealed the bacteriophage genomes to be double stranded DNA in the range of 140 kb in size and the restriction enzyme patterns of the DNAs indicate they are genetically related members of the Myoviridae family. This study showed that Campylobacter bacteriophage could easily be isolated from free-range chickens and form part of their normal microbiological biota of environmentally exposed birds.

  5. Bacteriophage-based therapy in cystic fibrosis-associated Pseudomonas aeruginosa infections: rationale and current status.

    PubMed

    Hraiech, Sami; Brégeon, Fabienne; Rolain, Jean-Marc

    2015-01-01

    Pulmonary infections involving Pseudomonas aeruginosa are among the leading causes of the deterioration of the respiratory status of cystic fibrosis (CF) patients. The emergence of multidrug-resistant strains in such populations, favored by iterative antibiotic cures, has led to the urgent need for new therapies. Among them, bacteriophage-based therapies deserve a focus. One century of empiric use in the ex-USSR countries suggests that bacteriophages may have beneficial effects against a large range of bacterial infections. Interest in bacteriophages has recently renewed in Western countries, and the in vitro data available suggest that bacteriophage-based therapy may be of significant interest for the treatment of pulmonary infections in CF patients. Although the clinical data concerning this specific population are relatively scarce, the beginning of the first large randomized study evaluating bacteriophage-based therapy in burn infections suggests that the time has come to assess the effectiveness of this new therapy in CF P. aeruginosa pneumonia. Consequently, the aim of this review is, after a brief history, to summarize the evidence concerning bacteriophage efficacy against P. aeruginosa and, more specifically, the in vitro studies, animal models, and clinical trials targeting CF.

  6. Bacteriophage-based therapy in cystic fibrosis-associated Pseudomonas aeruginosa infections: rationale and current status

    PubMed Central

    Hraiech, Sami; Brégeon, Fabienne; Rolain, Jean-Marc

    2015-01-01

    Pulmonary infections involving Pseudomonas aeruginosa are among the leading causes of the deterioration of the respiratory status of cystic fibrosis (CF) patients. The emergence of multidrug-resistant strains in such populations, favored by iterative antibiotic cures, has led to the urgent need for new therapies. Among them, bacteriophage-based therapies deserve a focus. One century of empiric use in the ex-USSR countries suggests that bacteriophages may have beneficial effects against a large range of bacterial infections. Interest in bacteriophages has recently renewed in Western countries, and the in vitro data available suggest that bacteriophage-based therapy may be of significant interest for the treatment of pulmonary infections in CF patients. Although the clinical data concerning this specific population are relatively scarce, the beginning of the first large randomized study evaluating bacteriophage-based therapy in burn infections suggests that the time has come to assess the effectiveness of this new therapy in CF P. aeruginosa pneumonia. Consequently, the aim of this review is, after a brief history, to summarize the evidence concerning bacteriophage efficacy against P. aeruginosa and, more specifically, the in vitro studies, animal models, and clinical trials targeting CF. PMID:26213462

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

    PubMed Central

    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. PMID:26413062

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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.

  12. Differentiation of Proteus mirabilis by bacteriophage typing and the Dienes reaction.

    PubMed Central

    Hickman, F W; Farmer, J J

    1976-01-01

    A provisional typing schema based on sensitivity to 23 bacteriophages has been established for Proteus mirabilis. Seventy-three bacteriophages were isolated on strains of P. mirabilis (64), P. vulgaris (1), P. morganii (7), and P. rettgeri (1), but those isolated on P. mirabilis were the most useful in differentiating other strains of . mirabilis. From the 73 phages studied, the best 23 were chosen by computer analysis for the provisional system, which was then used to study P. mirabilis infections in a 500-bed general hospital. All patient isolates for 19 months were saved and then compared by bacteriophage typing and the Dienes reaction in a retrospective study. There was evidence for only three instances of cross-infection or -colonization during this time. Bacteriophage typing was very sensitive in differentiating strains, since 200 strains were differentiated into 113 different lysis patterns and 94% were typable. The Dienes reaction was useful at times but often gave reactions that were difficult to read or that changed when the tests were repeated. The bacteriophages described by Schmidt and Jeffries were also evaluated and proved useful in combination with ours. The value of bacteriophage typing was clearly established, and work toward a standardized schema for P. mirabilis should continue. Images PMID:773962

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

    PubMed

    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.

  14. Isolation and characterization of a bacteriophage lytic for Desulfovibrio salexigens, a salt-requiring, sulfate-reducing bacterium

    SciTech Connect

    Kamimura, Kazuo; Araki, Michio )

    1989-03-01

    A bacteriophage that lysed Desulfovibrio salexigens cells was isolated from marine sediments and preliminarily characterized by electron microscopy and electrophoretic analysis of structural proteins and genomic nucleic acid. The bacteriophage had an icosahedral head and a long flexible tail, and the buoyant density of the bacteriophage particles was 1.468 g/ml in cesium chloride. The particles consisted of a double-stranded DNA molecule about 33 kilobase pairs long and at least 11 structural proteins.

  15. Bacteriophage-nanocomposites: an easy and reproducible method for the construction, handling, storage and transport of conjugates for deployment of bacteriophages active against Pseudomonas aeruginosa.

    PubMed

    Cooper, Ian R; Illsley, Matthew; Korobeinyk, Alina V; Whitby, Raymond L D

    2015-04-01

    The purpose of this work was proof of concept to develop a novel, cost effective protocol for the binding of bacteriophages to a surface without loss of function, after storage in various media. The technology platform involved covalently bonding bacteriophage 13 (a Pseudomonas aeruginosa bacteriophage) to two magnetised multiwalled carbon nanotube scaffolds using a series of buffers; bacteriophage-nanotube (B-N) conjugates were efficacious after storage at 20 °C for six weeks. B-N conjugates were added to human cell culture in vitro for 9 days without causing necrosis and apoptosis. B-N conjugates were frozen (-20 °C) in cell culture media for several weeks, after which recovery from the human cell culture medium was possible using a simple magnetic separation technique. The retention of viral infective potential was demonstrated by subsequent spread plating onto lawns of susceptible P. aeruginosa. Analysis of the human cell culture medium revealed the production of interleukins by the human fibroblasts upon exposure to the bacteriophage. One day after exposure, IL-8 levels transitorily increased between 60 and 100 pg/mL, but this level was not found on any subsequent days, suggesting an initial but not long lasting response. This paper outlines the development of a method to deliver antimicrobial activity to a surface that is small enough to be combined with other materials. To our knowledge at time of publication, this is the first report of magnetically coupled bacteriophages specific to human pathogens which can be recovered from test systems, and could represent a novel means to conditionally deploy antibacterial agents into living eukaryotic systems without the risks of some antibiotic therapies.

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

    PubMed Central

    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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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

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

    PubMed

    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

  20. Application of bacteriophages for detection of foodborne pathogens.

    PubMed

    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

  1. An electron microscopic study of bacteriophages from marine waters

    NASA Astrophysics Data System (ADS)

    Frank, Hermann; Moebus, Karlheinz

    1987-12-01

    The morphology of 75 bacteriophage strains isolated from water samples collected in the North Sea or in the northern Atlantic was studied by electron microscopy. Only tailed phages were observed (bradley groups A, B, and C). According to structural similarities, the strains are ascribed to 12 groups, 5 of which comprise types of marine phages not reported before. Four of these 5 groups include phage types that have not been detected from any other source. Among the phages isolated from northern Atlantic water a high incidence was observed of strains the particles of which have long appendages. Certain types of the northern Atlantic phages investigated were derived only from samples collected either east or west of the Azores. This finding agrees with former observations pointing to the existence of different populations of closely related bacteria east and west, respectively, of the northern Mid-Atlantic Ridge.

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

    PubMed

    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.

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

    PubMed

    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.

  4. Targeting glioblastoma via intranasal administration of Ff bacteriophages

    PubMed Central

    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

  5. Capstan Friction Model for DNA Ejection from Bacteriophages

    NASA Astrophysics Data System (ADS)

    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.

  6. Characterization of a thermophilic bacteriophage of Geobacillus kaustophilus.

    PubMed

    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.

  7. Reduction of invasive bacteria in ethanol fermentations using bacteriophages.

    PubMed

    Worley-Morse, Thomas O; Deshusses, Marc A; Gunsch, Claudia K

    2015-08-01

    Invasive Lactobacillus bacteria inhibit ethanol fermentations and reduce final product yields. Due to the emergence of antibiotic resistant strains of Lactobacillus spp., alternative disinfection strategies are needed for ethanol fermentations. The feasibility of using the bacteriophage (phage) 8014-B2 to control Lactobacillus plantarum in ethanol fermentations by Saccharomyces cerevisiae was investigated. In 48 h media-based shake flask fermentations, phages achieved greater than 3-log inactivation of L. plantarum, protected final ethanol yields, and maintained yeast viability. The phage-based bacterial disinfection rates depended on both the initial phage and bacterial concentrations. Furthermore, a simple set of kinetic equations was used to model the yeast, bacteria, phage, reducing sugars, and ethanol concentrations over the course of 48 h, and the various kinetic parameters were determined. Taken together, these results demonstrate the applicability of phages to reduce L. plantarum contamination and to protect final product yields in media-based fermentations.

  8. Application of bacteriophages for detection of foodborne pathogens.

    PubMed

    Schmelcher, Mathias; Loessner, Martin J

    2014-01-01

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

  9. Properties of the streptomycete temperate bacteriophage FP43.

    PubMed

    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.

  10. Application of bacteriophages for detection of foodborne pathogens

    PubMed Central

    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

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

    PubMed

    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.

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

    PubMed

    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. PMID:25827218

  13. Physical and genetical analysis of bacteriophage T4 generalized transduction.

    PubMed

    Young, K K; Edlin, G

    1983-01-01

    This report describes a comparison of the efficiency of transduction of genes in E. coli by the generalized transducing bacteriophages T4GT7 and P1CM. Both phages are capable of transducing many genetic markers in E. coli although the frequency of transduction for particular genes varies over a wide range. The frequency of transduction for most genes depends on which transducing phage is used as well as on the donor and recipient bacterial strains. Analysis of T4GT7 phage lysates by cesium chloride density gradient centrifugation shows that transducing phage particles contain primarily bacterial DNA and carry little, if any, phage DNA. In this regard transducing phages P1CM and T4GT7 are similar; both phages package either bacterial or phage DNA but not both DNAs into the same particle.

  14. Targeting glioblastoma via intranasal administration of Ff bacteriophages.

    PubMed

    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.

  15. Protein engineering with biosynthesized libraries from Bordetella bronchiseptica bacteriophage.

    PubMed

    Yuan, Tom Z; Overstreet, Cathie M; Moody, Issa S; Weiss, Gregory A

    2013-01-01

    Phage display offers a powerful approach to engineer protein affinity. A naturally occurring analog to phage display, the Bordetella bronchiseptica bacteriophage (BP) employs a highly variable protein termed the major tropism determinant (Mtd) to recognize its dynamic host. Propagation of BP provides a self-made phage library (SMPL) with vast numbers of phage particles, each displaying a single Mtd variant. We report applying the diversity of the BP-SMPL to access a tyrosine-rich library of Mtd variants. Expression of the SMPL-engineered Mtd variant as a GST-bound fusion protein demonstrated specific binding to the target T4 lysozyme with dissociation constants in the sub-micromolar range. The results guide future experiments with SMPLs applied to protein engineering.

  16. Bacteriophages and genetic mobilization in sewage and faecally polluted environments

    PubMed Central

    Muniesa, Maite; Imamovic, Lejla; Jofre, Juan

    2011-01-01

    Summary Bacteriophages are one of the most abundant entities on the planet and are present in high concentrations within humans and animals, mostly in the gut. Phages that infect intestinal bacteria are released by defecation and remain free in extra‐intestinal environments, where they usually persist for longer than their bacterial hosts. Recent studies indicate that a large amount of the genetic information in bacterial genomes and in natural environments is of phage origin. In addition, metagenomic analysis reveals that a substantial number of bacterial genes are present in viral DNA in different environments. These facts support the belief that phages can play a significant role in horizontal gene transfer between bacteria. Bacteriophages are known to transfer genes by generalized and specialized transduction and indeed there are some examples of phages found in the environment carrying and transducing genes of bacterial origin. A successful transduction in the environment requires certain conditions, e.g. phage and bacterial numbers need to exceed certain threshold concentrations, the bacteria need to exist in an infection‐competent physiological state, and lastly, the physical conditions in the environment (pH, temperature, etc. of the supporting matrix) have to be suitable for phage infection. All three factors are reviewed here, and the available information suggests: (i) that the number of intestinal bacteria and phages in faecally contaminated environments guarantees bacteria–phage encounters, (ii) that transduction to intestinal bacteria in the environment is probable, and (iii) that transduction is more frequent than previously thought. Therefore, we suggest that phage‐mediated horizontal transfer between intestinal bacteria, or between intestinal and autochthonous bacteria in extra‐intestinal environments, might take place and that its relevance for the emergence of new bacterial strains and potential pathogens should not be ignored. PMID

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

    PubMed

    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

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

    PubMed

    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

  19. Electron microscopic analysis of partially replicated bacteriophage T7 DNA.

    PubMed Central

    Burck, K B; Scraba, D G; Miller, R C

    1979-01-01

    Partially replicated bacteriophage T7 DNA was isolated from Escherichia coli infected with UV-irradiated T7 bacteriophage and was analyzed by electron microscopy. The analysis determined the distribution of eye forms and forks in the partially replicated molecules. Eye forms and forks in unit length molecules were aligned with respect to the left end of the T7 genome, and segments were scored for replication in each molecule. The resulting histogram showed that only the left 25 to 30% of the molecules was replicated. Several different origins of DNA replication were used to initiate replication in the UV-irradiated experiments in which 32P-labeled progeny DNA from UV-irradiated phage was annealed with ordered restriction fragments of T7 DNA (K. B. Burck and R. C. Miller, Jr., Proc. Natl. Acad. Sci. U.S.A. 75:6144--6148, 1978). Both analyses support partial-replica hypotheses (N. A. Barricelli and A. H. Doermann, Virology 13:460--476, 1961; Doermann et al., J. Cell. comp. Physiol. 45[Suppl.]:51--74, 1955) as an explanation for the distribution of marker rescue frequencies during cross-reactivation; i.e., replication proceeds in a bidirectional manner from an origin to a site of UV damage, and those regions of the genome which replicate most efficiently are rescued most efficiently by a coinfecting phage. In addition, photoreactivation studies support the hypothesis that thymine dimers are the major UV damage blocking cross-reactivation in the right end of the T7 genome. Images PMID:291738

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

    PubMed Central

    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

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

    PubMed

    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

  2. Mobilization of Genomic Islands of Staphylococcus aureus by Temperate Bacteriophage.

    PubMed

    Moon, Bo Youn; Park, Joo Youn; Robinson, D Ashley; Thomas, Jonathan C; Park, Yong Ho; Thornton, Justin A; Seo, Keun Seok

    2016-01-01

    The virulence of Staphylococcus aureus, in both human and animal hosts, is largely influenced by the acquisition of mobile genetic elements (MGEs). Most S. aureus strains carry a variety of MGEs, including three genomic islands (νSaα, νSaβ, νSaγ) that are diverse in virulence gene content but conserved within strain lineages. Although the mobilization of pathogenicity islands, phages and plasmids has been well studied, the mobilization of genomic islands is poorly understood. We previously demonstrated the mobilization of νSaβ by the adjacent temperate bacteriophage ϕSaBov from strain RF122. In this study, we demonstrate that ϕSaBov mediates the mobilization of νSaα and νSaγ, which are located remotely from ϕSaBov, mostly to recipient strains belonging to ST151. Phage DNA sequence analysis revealed that chromosomal DNA excision events from RF122 were highly specific to MGEs, suggesting sequence-specific DNA excision and packaging events rather than generalized transduction by a temperate phage. Disruption of the int gene in ϕSaBov did not affect phage DNA excision, packaging, and integration events. However, disruption of the terL gene completely abolished phage DNA packing events, suggesting that the primary function of temperate phage in the transfer of genomic islands is to allow for phage DNA packaging by TerL and that transducing phage particles are the actual vehicle for transfer. These results extend our understanding of the important role of bacteriophage in the horizontal transfer and evolution of genomic islands in S. aureus.

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

    PubMed

    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.

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

    PubMed

    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. Mobilization of Genomic Islands of Staphylococcus aureus by Temperate Bacteriophage

    PubMed Central

    Moon, Bo Youn; Park, Joo Youn; Robinson, D. Ashley; Thomas, Jonathan C.; Park, Yong Ho; Thornton, Justin A.; Seo, Keun Seok

    2016-01-01

    The virulence of Staphylococcus aureus, in both human and animal hosts, is largely influenced by the acquisition of mobile genetic elements (MGEs). Most S. aureus strains carry a variety of MGEs, including three genomic islands (νSaα, νSaβ, νSaγ) that are diverse in virulence gene content but conserved within strain lineages. Although the mobilization of pathogenicity islands, phages and plasmids has been well studied, the mobilization of genomic islands is poorly understood. We previously demonstrated the mobilization of νSaβ by the adjacent temperate bacteriophage ϕSaBov from strain RF122. In this study, we demonstrate that ϕSaBov mediates the mobilization of νSaα and νSaγ, which are located remotely from ϕSaBov, mostly to recipient strains belonging to ST151. Phage DNA sequence analysis revealed that chromosomal DNA excision events from RF122 were highly specific to MGEs, suggesting sequence-specific DNA excision and packaging events rather than generalized transduction by a temperate phage. Disruption of the int gene in ϕSaBov did not affect phage DNA excision, packaging, and integration events. However, disruption of the terL gene completely abolished phage DNA packing events, suggesting that the primary function of temperate phage in the transfer of genomic islands is to allow for phage DNA packaging by TerL and that transducing phage particles are the actual vehicle for transfer. These results extend our understanding of the important role of bacteriophage in the horizontal transfer and evolution of genomic islands in S. aureus. PMID:26953931

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

    PubMed

    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

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

    PubMed Central

    2011-01-01

    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. PMID:21733190

  8. Infrared Astronomy

    NASA Astrophysics Data System (ADS)

    Mampaso, A.; Prieto, M.; Sánchez, F.

    2004-01-01

    What do we understand of the birth and death of stars? What is the nature of the tiny dust grains that permeate our Galaxy and other galaxies? And how likely is the existence of brown dwarfs, extrasolar planets or other sub-stellar mass objects? These are just a few of the questions that can now be addressed in a new era of infrared observations. IR astronomy has been revolutionised over the past few years by the widespread availability of large, very sensitive IR arrays and the success of IR satellites (IRAS in particular). Several IR space missions due for launch over the next few years promise an exciting future too. For these reasons, the IV Canary Islands Winter School of Astrophysics was dedicated to this burgeoning field. Its primary goal was to introduce graduate students and researchers from other areas to the important new observations and physical ideas that are emerging in this wide-ranging field of research. Lectures from nine leading researchers, renowned for their teaching abilities, are gathered in this volume. These nine chapters provide an excellent introduction as well as a thorough and up-to-date review of developments - essential reading for graduate students entering IR astronomy, and professionals from other areas who realise the importance that IR astronomy may have on their research.

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed Central

    Urban-Chmiel, Renata; Wernicki, Andrzej; Stęgierska, Diana; Dec, Marta; Dudzic, Anna; Puchalski, Andrzej

    2015-01-01

    Aim of Study 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. Material and Methods 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). Results 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. Conclusions The results obtained indicate the need for further research aimed

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

    PubMed

    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.

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

    PubMed Central

    Robinson, J. W.

    1972-01-01

    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 Qβ 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. PMID:4564257

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

    PubMed Central

    Smith, Lauren L.; Buckley, Rebecca; Lugar, Patricia

    2014-01-01

    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 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 to 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 adults 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. Conclusion: 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

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

    PubMed

    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 (p<0.05) Salmonella Typhimurium counts in 1.6 and 2.5 log10 colony-forming units (CFU)/mL, respectively, after 24 h. Before the in vivo treatment with bacteriophages, 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. Attenuation and colloidal mobilization of bacteriophages in natural sediments under anoxic as compared to oxic conditions.

    PubMed

    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.

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

    PubMed

    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

  17. Stability and activity of an Enterobacter aerogenes-specific bacteriophage under simulated gastro-intestinal conditions.

    PubMed

    Verthé, K; Possemiers, S; Boon, N; Vaneechoutte, M; Verstraete, W

    2004-09-01

    A bacteriophage, designated UZ1 and showing lytic activity against a clinically important strain (BE1) of Enterobacter aerogenes was isolated from hospital sewage. The stability and lytic activity against this strain under simulated gastro-intestinal conditions was evaluated. After addition of bacteriophage UZ1 to a liquid feed at gastric pH 2, the phage was immediately inactivated and could not be recovered. However, by use of an antacid to neutralize stomach acidity, no significant changes in phage titer were observed after 2 h incubation at 37 degrees C. After supplementing pancreatic juice and further incubation for 4 h, the phage titer remained stable. The persistence of UZ1 in a mixed microbial ecosystem that was representative for the large intestine was monitored using an in vitro simulation of the human intestinal microbial ecosystem. A pulse administration of bacteriophage UZ1 at a concentration of 10(5) plaque-forming units (PFU)/ml to reactor 3 (which simulates the ascending colon) showed that, in the absence of the host, bacteriophage UZ1 persisted for 13 days in the simulated colon, while the theoretical washout was calculated at 16 days. To assess its lytic activity in an intestinal microbial ecosystem, a green fluorescent protein (gfp)-labeled E. aerogenes BE1 strain was constructed and gfp-specific primers were designed in order to quantify the host strain using real-time PCR. It was observed that bacteriophage UZ1 was able to replicate and showed lytic activity against E. aerogenes BE1/ gfp in an intestinal microbial ecosystem. Indeed, after 17 h a 2 log unit reduction of E. aerogenes BE1/ gfp was measured as compared with the assay without bacteriophage UZ1, while the phage titer increased by 2 log units at an initial multiplicity of infection of 0.07 PFU/colony-forming unit. This is the first report of an in vitro model to study bacteriophage activity in the complex intestinal microbial community.

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  1. Method of administration affects the ability of bacteriophage to prevent colibacillosis in 1-day-old broiler chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacteriophages are viruses that kill bacteria. They are plentiful in nature with no known activity to human or animal cells, making them an attractive alternative to antibiotics. The objective of this research was to determine if a coarse or a fine spray of bacteriophage would prevent colibacillos...

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

    PubMed

    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.

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

    PubMed

    Kim, Young Jun; Jin, Young-Hyun; Salieb-Beugelaar, Georgette B; Nam, Chang-Hoon; Stieglitz, Thomas

    2014-02-01

    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. PMID:24448635

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

    PubMed

    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. Bacteriophage adenine methyltransferase: a life cycle regulator? Modelled using Vibrio harveyi myovirus like.

    PubMed

    Bochow, S; Elliman, J; Owens, L

    2012-11-01

    The adenine methyltransferase (DAM) gene methylates GATC sequences that have been demonstrated in various bacteria to be a powerful gene regulator functioning as an epigenetic switch, particularly with virulence gene regulation. However, overproduction of DAM can lead to mutations, giving rise to variability that may be important for adaptation to environmental change. While most bacterial hosts carry a DAM gene, not all bacteriophage carry this gene. Currently, there is no literature regarding the role DAM plays in life cycle regulation of bacteriophage. Vibrio campbellii strain 642 carries the bacteriophage Vibrio harveyi myovirus like (VHML) that has been proven to increase virulence. The complete genome sequence of VHML bacteriophage revealed a putative adenine methyltransferase gene. Using VHML, a new model of phage life cycle regulation, where DAM plays a central role between the lysogenic and lytic states, will be hypothesized. In short, DAM methylates the rha antirepressor gene and once methylation is removed, homologous CI repressor protein becomes repressed and non-functional leading to the switching to the lytic cycle. Greater understanding of life cycle regulation at the genetic level can, in the future, lead to the genesis of chimeric bacteriophage with greater control over their life cycle for their safe use as probiotics within the aquaculture industry. PMID:22681538

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

    PubMed

    Kim, Young Jun; Jin, Young-Hyun; Salieb-Beugelaar, Georgette B; Nam, Chang-Hoon; Stieglitz, Thomas

    2014-02-01

    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.

  7. Modeling removal of bacteriophages MS2 and PRD1 by dune recharge at Castricum, Netherlands

    NASA Astrophysics Data System (ADS)

    Schijven, Jack F.; Hoogenboezem, Wim; Hassanizadeh, S. Majid; Peters, Jos H.

    1999-04-01

    Removal of model viruses by dune recharge was studied at a field site in the dune area of Castricum, Netherlands. Recharge water was dosed with bacteriophages MS2 and PRD1 for 11 days at a constant concentration in a 10- by 15-m compartment that was isolated in a recharge basin. Breakthrough was monitored for 120 days at six wells with their screens along a flow line. Concentrations of both phages were reduced about 3 log10 within the first 2.4 m and another 5 log10 in a linear fashion within the following 27 m. A model accounting for one-site kinetic attachment as well as first-order inactivation was employed to simulate the bacteriophage breakthrough curves. The major removal process was found to be attachment of the bacteriophages. Detachment was very slow. After passage of the pulse of dosed bacteriophages, there was a long tail whose slope corresponds to the inactivation rate coefficient of 0.07-0.09 day-1 for attached bacteriophages. The end of the rising and the start of the declining limbs of the breakthrough curves could not be simulated completely, probably because of an as yet unknown process.

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

    PubMed

    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.

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

    PubMed

    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.

  10. Role of bacteriophages in STEC infections: new implications for the design of prophylactic and treatment approaches

    PubMed Central

    Amorim, Jaime H.; Del Cogliano, Manuel E.; Fernandez-Brando, Romina J.; Bilen, Marcos F.; Jesus, Monica R.; Luiz, Wilson B.; Palermo, Marina S.; Ferreira, Rita C.C.; Servat, Esteban G.; Ghiringhelli, Pablo D.; Ferreira, Luis C.S; Bentancor, Leticia V.

    2014-01-01

    Shiga toxin (Stx) is considered the main virulence factor in Shiga toxin-producing Escherichia coli (STEC) infections. Previously we reported the expression of biologically active Stx by eukaryotic cells in vitro and in vivo following transfection with plasmids encoding Stx under control of the native bacterial promoter 1,2. Since stx genes are present in the genome of lysogenic bacteriophages, here we evaluated the relevance of bacteriophages during STEC infection. We used the non-pathogenic E. coli C600 strain carrying a lysogenic 933W mutant bacteriophage in which the stx operon was replaced by a gene encoding the green fluorescent protein (GFP). Tracking GFP expression using an In Vivo Imaging System (IVIS), we detected fluorescence in liver, kidney, and intestine of mice infected with the recombinant E. coli strain after treatment with ciprofloxacin, which induces the lytic replication and release of bacteriophages. In addition, we showed that chitosan, a linear polysaccharide composed of d-glucosamine residues and with a number of commercial and biomedical uses, had strong anti-bacteriophage effects, as demonstrated at in vitro and in vivo conditions. These findings bring promising perspectives for the prevention and treatment of haemolytic uremic syndrome (HUS) cases. PMID:25580222

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

    PubMed

    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. PMID:23391228

  12. Photonic approach to the selective inactivation of viruses with a near-infrared ultrashort pulsed laser

    NASA Astrophysics Data System (ADS)

    Tsen, K. T.; Tsen, Shaw-Wei D.; Fu, Q.; Lindsay, S. M.; Kibler, K.; Jacobs, B.; Wu, T. C.; Li, Zhe; Yan, Hao; Cope, Stephanie; Vaiana, Sara; Kiang, Juliann G.

    2010-02-01

    We report a photonic approach for selective inactivation of viruses with a near-infrared ultrashort pulsed (USP) laser. We demonstrate that this method can selectively inactivate viral particles ranging from nonpathogenic viruses such as M13 bacteriophage, tobacco mosaic virus (TMV) to pathogenic viruses like human papillomavirus (HPV) and human immunodeficiency virus (HIV). At the same time sensitive materials like human Jurkat T cells, human red blood cells, and mouse dendritic cells remain unharmed. Our photonic approach could be used for the disinfection of viral pathogens in blood products and for the treatment of blood-borne viral diseases in the clinic.

  13. Structure and assembly of bacteriophage T4 head.

    PubMed

    Rao, Venigalla B; Black, Lindsay W

    2010-01-01

    The bacteriophage T4 capsid is an elongated icosahedron, 120 nm long and 86 nm wide, and is built with three essential proteins; gp23*, which forms the hexagonal capsid lattice, gp24*, which forms pentamers at eleven of the twelve vertices, and gp20, which forms the unique dodecameric portal vertex through which DNA enters during packaging and exits during infection. The past twenty years of research has greatly elevated the understanding of phage T4 head assembly and DNA packaging. The atomic structure of gp24 has been determined. A structural model built for gp23 using its similarity to gp24 showed that the phage T4 major capsid protein has the same fold as that found in phage HK97 and several other icosahedral bacteriophages. Folding of gp23 requires the assistance of two chaperones, the E. coli chaperone GroEL and the phage coded gp23-specific chaperone, gp31. The capsid also contains two non-essential outer capsid proteins, Hoc and Soc, which decorate the capsid surface. The structure of Soc shows two capsid binding sites which, through binding to adjacent gp23 subunits, reinforce the capsid structure. Hoc and Soc have been extensively used in bipartite peptide display libraries and to display pathogen antigens including those from HIV, Neisseria meningitides, Bacillus anthracis, and FMDV. The structure of Ip1*, one of the components of the core, has been determined, which provided insights on how IPs protect T4 genome against the E. coli nucleases that degrade hydroxymethylated and glycosylated T4 DNA. Extensive mutagenesis combined with the atomic structures of the DNA packaging/terminase proteins gp16 and gp17 elucidated the ATPase and nuclease functional motifs involved in DNA translocation and headful DNA cutting. Cryo-EM structure of the T4 packaging machine showed a pentameric motor assembled with gp17 subunits on the portal vertex. Single molecule optical tweezers and fluorescence studies showed that the T4 motor packages DNA at a rate of up to 2000 bp

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    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

  16. Comparison of Five Bacteriophages as Models for Viral Aerosol Studies

    PubMed Central

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

    2014-01-01

    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

  17. Enhanced Recovery of Airborne T3 Coliphage and Pasteurella pestis Bacteriophage by Means of a Presampling Humidification Technique

    PubMed Central

    Hatch, M. T.; Warren, J. C.

    1969-01-01

    This paper reports a series of experiments in which two methods of collecting airborne bacteriophage particles were compared. A standard aerosol sampler, the AGI-30, was evaluated for its competence in measuring the content of bacteriophage aerosols. It was used alone or with a prewetting or humidification device (humidifier bulb) to recover T3 coliphage and Pasteurella pestis bacteriophage particles from aerosols maintained at 21 C and varied relative humidity. Collection of bacteriophage particles via the humidifier bulb altered both the initial recovery level and the apparent biological decay. Sampling airborne bacteriophage particles by the AGI-30 alone yielded data that apparently underestimated the maximal number of potentially viable particles within the aerosol, sometimes by as much as 3 logs. PMID:4891719

  18. Bacteriophage inactivation by UV-A illuminated fullerenes: role of nanoparticle-virus association and biological targets.

    PubMed

    Badireddy, Appala Raju; Budarz, Jeffrey Farner; Chellam, Shankararaman; Wiesner, Mark R

    2012-06-01

    Inactivation rates of the MS2 bacteriophage and (1)O(2) generation rates by four different photosensitized aqueous fullerene suspensions were in the same order: aqu-nC(60) < C(60)(OH)(6) ≈ C(60)(OH)(24) < C(60)(NH(2))(6). Alterations to capsid protein secondary structures and protein oxidation were inferred by detecting changes in infrared vibrational frequencies and carbonyl groups respectively. MS2 inactivation appears to be the result of loss of capsid structural integrity (localized deformation) and the reduced ability to eject genomic RNA into its bacterial host. Evidence is also presented for possible capsid rupture in MS2 exposed to UV-A illuminated C(60)(NH(2))(6) through TEM imagery and detection of RNA infrared fingerprints in ATR-FTIR spectra. Fullerene-virus mixtures were also directly visualized in the aqueous phase using a novel enhanced darkfield transmission optical microscope fitted with a hyperspectral imaging (HSI) spectrometer. Perturbations in intermolecular extended chains, HSI, and electrostatic interactions suggest that inactivation is a function of the relative proximity between nanoparticles and viruses and (1)O(2) generation rate. MS2 log survival ratios were linearly related to CT (product of (1)O(2) concentration C and exposure time T) demonstrating the applicability of classical Chick-Watson kinetics for all fullerenes employed in this study. Results suggest that antiviral properties of fullerenes can be increased by adjusting the type of surface functionalization and extent of cage derivatization thereby increasing the (1)O(2) generation rate and facilitating closer association with biological targets. PMID:22545948

  19. Molecular Basis for Lytic Bacteriophage Resistance in Enterococci

    PubMed Central

    Duerkop, Breck A.; Huo, Wenwen; Bhardwaj, Pooja

    2016-01-01

    ABSTRACT The human intestine harbors diverse communities of bacteria and bacteriophages. Given the specificity of phages for their bacterial hosts, there is growing interest in using phage therapies to combat the rising incidence of multidrug-resistant bacterial infections. A significant barrier to such therapies is the rapid development of phage-resistant bacteria, highlighting the need to understand how bacteria acquire phage resistance in vivo. Here we identify novel lytic phages in municipal raw sewage that kill Enterococcus faecalis, a Gram-positive opportunistic pathogen that resides in the human intestine. We show that phage infection of E. faecalis requires a predicted integral membrane protein that we have named PIPEF (for phage infection protein from E. faecalis). We find that PIPEF is conserved in E. faecalis and harbors a 160-amino-acid hypervariable region that determines phage tropism for distinct enterococcal strains. Finally, we use a gnotobiotic mouse model of in vivo phage predation to show that the sewage phages temporarily reduce E. faecalis colonization of the intestine but that E. faecalis acquires phage resistance through mutations in PIPEF. Our findings define the molecular basis for an evolutionary arms race between E. faecalis and the lytic phages that prey on them. They also suggest approaches for engineering E. faecalis phages that have altered host specificity and that can subvert phage resistance in the host bacteria. PMID:27578757

  20. Molecular interactions in the priming complex of bacteriophage T7

    PubMed Central

    Kulczyk, Arkadiusz W.; Richardson, Charles C.

    2012-01-01

    The lagging-strand DNA polymerase requires an oligoribonucleotide, synthesized by DNA primase, to initiate the synthesis of an Okazaki fragment. In the replication system of bacteriophage T7 both DNA primase and DNA helicase activities are contained within a single protein, the bifunctional gene 4 protein (gp4). Intermolecular interactions between gp4 and T7 DNA polymerase are crucial for the stabilization of the oligoribonucleotide, its transfer to the polymerase, and its extension by DNA polymerase. We have identified conditions necessary to assemble the T7 priming complex and characterized its biophysical properties using fluorescence anisotropy. In order to reveal molecular interactions that occur during delivery of the oligoribonucleotide to DNA polymerase, we have used four genetically altered gp4 to demonstrate that both the RNA polymerase and the zinc-finger domains of DNA primase are involved in the stabilization of the priming complex and in sequence recognition in the DNA template. We find that the helicase domain of gp4 contributes to the stability of the complex by binding to the ssDNA template. The C-terminal tail of gp4 is not required for complex formation. PMID:22645372

  1. A promiscuous DNA packaging machine from bacteriophage T4.

    PubMed

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

    2011-01-01

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

  2. Novel N4 Bacteriophages Prevail in the Cold Biosphere.

    PubMed

    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.

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

    PubMed

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

    2011-01-01

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

  4. [New Virulent Bacteriophages Active against Multiresistant Pseudomonas aeruginosa Strains].

    PubMed

    Balarjishvili, N Sh; Kvachadze, L I; Kutateladze, M I; Meskhi, T Sh; Pataridze, T K; Berishvili, T A; Tevdoradze, E Sh

    2015-01-01

    The sensitivity of 512 newly isolated Pseudomonas aeruginosa clinical strains to six classes of anti-microbial preparations has been studied. Antibiotic-resistant strains were selected and genotyped. Three new virulent bacteriophages of the families Myoviridae and Podoviridae were isolated against these strains. The parameters of the intracellular phage development cycle were established, and the influence of inactivating factors (temperature, pH, and UV exposure) on phage viability was studied. The molecular weight of the phage genome was determined. Phage DNA restriction analysis and polyacrylamide gel electrophoresis in the presence of envelope protein SDS were carried out. The plating efficacy of phages on 28 genetically distant antibiotic-resistant P. aeruginosa strains was studied. It was established that 26 of them were lysed by phages with a high efficacy. The range of antibacterial action of the studied phages and their mixtures on 427 multi-drug-resistant clinical isolates was assessed. It is shown that including these phages in one multicomponent preparation enhanced their lytic activity. PMID:26859962

  5. Bacteriophages and phage-derived proteins--application approaches.

    PubMed

    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

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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).

  8. DNA damage under simulated extraterrestrial conditions in bacteriophage T7

    NASA Astrophysics Data System (ADS)

    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.

  9. Factors affecting survival of bacteriophage on tomato leaf surfaces.

    PubMed

    Iriarte, F B; Balogh, B; Momol, M T; Smith, L M; Wilson, M; Jones, J B

    2007-03-01

    The ability of bacteriophage to persist in the phyllosphere for extended periods is limited by many factors, including sunlight irradiation, especially in the UV zone, temperature, desiccation, and exposure to copper bactericides. The effects of these factors on persistence of phage and formulated phage (phage mixed with skim milk) were evaluated. In field studies, copper caused significant phage reduction if applied on the day of phage application but not if applied 4 or 7 days in advance. Sunlight UV was evaluated for detrimental effects on phage survival on tomato foliage in the field. Phage was applied in the early morning, midmorning, early afternoon, and late evening, while UVA plus UVB irradiation and phage populations were monitored. The intensity of UV irradiation positively correlated with phage population decline. The protective formulation reduced the UV effect. In order to demonstrate direct effects of UV, phage suspensions were exposed to UV irradiation and assayed for effectiveness against bacterial spot of tomato. UV significantly reduced phage ability to control bacterial spot. Ambient temperature had a pronounced effect on nonformulated phage but not on formulated phages. The effects of desiccation and fluorescent light illumination on phage were investigated. Desiccation caused a significant but only slight reduction in phage populations after 60 days, whereas fluorescent light eliminated phages within 2 weeks. The protective formulation eliminated the reduction caused by both of these factors. Phage persistence was dramatically affected by UV, while the other factors had less pronounced effects. Formulated phage reduced deleterious effects of the studied environmental factors. PMID:17259361

  10. Computational approaches to predict bacteriophage-host relationships.

    PubMed

    Edwards, Robert A; McNair, Katelyn; Faust, Karoline; Raes, Jeroen; Dutilh, Bas E

    2016-03-01

    Metagenomics has changed the face of virus discovery by enabling the accurate identification of viral genome sequences without requiring isolation of the viruses. As a result, metagenomic virus discovery leaves the first and most fundamental question about any novel virus unanswered: What host does the virus infect? The diversity of the global virosphere and the volumes of data obtained in metagenomic sequencing projects demand computational tools for virus-host prediction. We focus on bacteriophages (phages, viruses that infect bacteria), the most abundant and diverse group of viruses found in environmental metagenomes. By analyzing 820 phages with annotated hosts, we review and assess the predictive power of in silico phage-host signals. Sequence homology approaches are the most effective at identifying known phage-host pairs. Compositional and abundance-based methods contain significant signal for phage-host classification, providing opportunities for analyzing the unknowns in viral metagenomes. Together, these computational approaches further our knowledge of the interactions between phages and their hosts. Importantly, we find that all reviewed signals significantly link phages to their hosts, illustrating how current knowledge and insights about the interaction mechanisms and ecology of coevolving phages and bacteria can be exploited to predict phage-host relationships, with potential relevance for medical and industrial applications.

  11. Immobilization and molecular interactions between bacteriophage and lipopolysaccharide bilayers.

    PubMed

    Handa, Hitesh; Gurczynski, Stephen; Jackson, Matthew P; Mao, Guangzhao

    2010-07-20

    The paper describes immobilization methods of bacteriophage P22 and tailspike gp9 proteins isolated from P22 on atomic force microscope (AFM) probes. The paper also reports single molecule force spectroscopy (SMFS) using AFM of the immobilized P22 (or gp9) interactions with substrate-supported O-antigenic lipopolysaccharides (LPS) bilayers. LPS covers the outer membrane of gram-negative bacteria, such as Salmonella typhimurium. Evidence from AFM imaging and SMFS shows that immobilized P22 (or gp9) are capable of strong and multivalent binding to supported LPS. The most common rupture forces between P22 and LPS were identified to be 72, 130, 206, and 279 pN at force loading rate of 12,000 pN/s. The quantized unbinding force was found to decrease with decreasing force loading rate as predicted by the Bell model. By fitting the force data with the Bell model, an energy barrier of 55 kJ/mol was obtained. Evidence is also provided that demonstrates the resilience of phage to pH and temperature fluctuation as well as dehydration/rehydration cycles. The biospecific interactions between P22 and the LPS are relevant to cell infection, inflammation, cancer progression and metastasis, food safety, pharmaceuticals, and biosensor development. PMID:20481467

  12. Bioprocessing of bacteriophages via rapid drying onto microcrystals.

    PubMed

    Alvarez-Gonzalez, Eva; Alfadhel, Munerah; Mane, Parag; Ford, Steven J; Moore, Barry D; van der Walle, Christopher F

    2012-01-01

    We present an alternative bioprocess for bacteriophages involving room temperature coprecipitation of an aqueous mixture of phage (Siphoviridae) and a crystallizable carrier (glutamine or glycine) in excess of water miscible organic solvent (isopropanol or isobutanol). The resultant suspension of phage-coated microcrystals can be harvested by filtration and the residual solvent removed rapidly by air-drying at a relative humidity of 75%. Albumin or trehalose added at 5% w/w of the crystalline carrier provide for better stabilization of the phage during co-precipitation. Free-flowing dry powders generated from an aqueous solution of phage (∼13 log(10) pfu/mL) can be reconstituted in the same aqueous volume to a phage titer of almost 10 log(10) pfu/mL; high enough to permit subsequent formulation steps following bioprocessing. The phage-coated microcrystals remain partially stable at room temperature for at least one month, which compares favorably with phage immobilized into polyester microcarriers or lyophilized with excipient (1-5% polyethylene glycol 6000 or 0.1-0.5 M sucrose). We anticipate that this bioprocessing technique will have application to other phage families as required for the development of phage therapies. PMID:22052699

  13. Evaluation of Filters for Removal of Bacteriophages from Air1

    PubMed Central

    Washam, C. J.; Black, C. H.; Sandine, W. E.; Elliker, P. R.

    1966-01-01

    Glass wool, nonabsorbent cotton, fiberglass filter medium, and a commercial absolute filter were tested for effectiveness in removing aerosolized bacterial viruses under low flow rate (1 ft3/min) and high flow rate (10 to 25 ft3/min) air-flow conditions. Special equipment was designed for measurement of filter efficiencies under the two air-flow conditions. Under low air-flow rate test conditions, glass wool was only 98.543 to 99.83% efficient, whereas cotton (five layers), fiberglass medium (three layers), and the commercial absolute filter were at least 99.900, 99.999, and 99.999 efficient, respectively. Glass wool and cotton were not used under higher air-flow conditions because they were difficult to assemble in leak-tight filters. The commercial absolute filter and fiberglass medium (three layers) were at least 99.990 and 99.999% efficient, respectively, under the higher air flow conditions. A stainless-steel filter of simple design and fitted with three layers of fiberglass medium was found to be greater than 99.999% efficient in removing high concentrations (20,000 to 70,000 plaque-forming units per cubic foot) of aerosolized bacteriophages from air moving at a low flow rate (1 ft3/min). Use of this filter on pressure-vacuum tanks in the fermentation industry is suggested. Several other uses of such a filter are proposed. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:5927020

  14. The allosteric switching mechanism in bacteriophage MS2

    NASA Astrophysics Data System (ADS)

    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.

  15. Predicting Gene-Regulation Functions: Lessons from Temperate Bacteriophages

    PubMed Central

    Teif, Vladimir B.

    2010-01-01

    Gene-regulation functions (GRF) provide a unique characteristic of a cis-regulatory module (CRM), relating the concentrations of transcription factors (input) to the promoter activities (output). The challenge is to predict GRFs from the sequence. Here we systematically consider the lysogeny-lysis CRMs of different temperate bacteriophages such as the Lactobacillus casei phage A2, Escherichia coli phages λ, and 186 and Lactococcal phage TP901-1. This study allowed explaining a recent experimental puzzle on the role of Cro protein in the lambda switch. Several general conclusions have been drawn: 1), long-range interactions, multilayer assembly and DNA looping may lead to complex GRFs that cannot be described by linear functions of binding site occupancies; 2), in general, GRFs cannot be described by the Boolean logic, whereas a three-state non-Boolean logic suffices for the studied examples; 3), studied CRMs of the intact phages seemed to have a similar GRF topology (the number of plateaus and peaks corresponding to different expression regimes); we hypothesize that functionally equivalent CRMs might have topologically equivalent GRFs for a larger class of genetic systems; and 4) within a given GRF class, a set of mechanistic-to-mathematical transformations has been identified, which allows shaping the GRF before carrying out a system-level analysis. PMID:20371324

  16. Bacteriophages and Phage-Derived Proteins – Application Approaches

    PubMed Central

    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

  17. Novel N4 Bacteriophages Prevail in the Cold Biosphere

    PubMed Central

    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

  18. Temperature dependent bacteriophages of a tropical bacterial pathogen

    PubMed Central

    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

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Continuous in vitro evolution of bacteriophage RNA polymerase promoters

    NASA Technical Reports Server (NTRS)

    Breaker, R. R.; Banerji, A.; Joyce, G. F.

    1994-01-01

    Rapid in vitro evolution of bacteriophage T7, T3, and SP6 RNA polymerase promoters was achieved by a method that allows continuous enrichment of DNAs that contain functional promoter elements. This method exploits the ability of a special class of nucleic acid molecules to replicate continuously in the presence of both a reverse transcriptase and a DNA-dependent RNA polymerase. Replication involves the synthesis of both RNA and cDNA intermediates. The cDNA strand contains an embedded promoter sequence, which becomes converted to a functional double-stranded promoter element, leading to the production of RNA transcripts. Synthetic cDNAs, including those that contain randomized promoter sequences, can be used to initiate the amplification cycle. However, only those cDNAs that contain functional promoter sequences are able to produce RNA transcripts. Furthermore, each RNA transcript encodes the RNA polymerase promoter sequence that was responsible for initiation of its own transcription. Thus, the population of amplifying molecules quickly becomes enriched for those templates that encode functional promoters. Optimal promoter sequences for phage T7, T3, and SP6 RNA polymerase were identified after a 2-h amplification reaction, initiated in each case with a pool of synthetic cDNAs encoding greater than 10(10) promoter sequence variants.

  1. Characterizing Aquifer Heterogeneity Using Bacterial and Bacteriophage Tracers.

    PubMed

    Flynn, Raymond M; Mallèn, German; Engel, Marion; Ahmed, Ashraf; Rossi, Pierre

    2015-09-01

    Gravel aquifers act as important potable water sources in central western Europe, yet they are subject to numerous contamination pressures. Compositional and textural heterogeneity makes protection zone delineation around groundwater supplies in these units challenging; artificial tracer testing aids characterization. This paper reappraises previous tracer test results in light of new geological and microbiological data. Comparative passive gradient testing, using a fluorescent solute (Uranine), virus (H40/1 bacteriophage), and comparably sized bacterial tracers and , was used to investigate a calcareous gravel aquifer's ability to remove microbiological contaminants at a test site near Munich, Germany. Test results revealed relative recoveries could exceed those of H40/1 at monitoring wells, 10 m and 20 m from an injection well, by almost four times; recoveries varied by a factor of up to three between wells. Application of filtration theory suggested greater attenuation of H40/1 relative to similarly charged occurred due to differences in microorganism size, while estimated collision efficiencies appeared comparable. By contrast, more positively charged experienced greater attenuation at one monitoring point, while lower attenuation rates at the second location indicated the influence of geochemical heterogeneity. Test findings proved consistent with observations from nearby fresh outcrops that suggested thin open framework gravel beds dominated mass transport in the aquifer, while discrete intervals containing stained clasts reflect localized geochemical heterogeneity. Study results highlight the utility of reconciling outcrop observations with artificial tracer test responses, using microbiological tracers with well-defined properties, to characterize aquifer heterogeneity.

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

    PubMed

    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.

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

    PubMed

    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.

  4. Inhibition of DNA ejection from bacteriophage by Mg+2 counterions

    NASA Astrophysics Data System (ADS)

    Lee, Sell; Tran, C. V.; Nguyen, T. T.

    2011-03-01

    The problem of inhibiting viral DNA ejection from bacteriophages by multivalent counterions, specifically Mg+2 counterions, is studied. Experimentally, it is known that MgSO4 salt has a strong and nonmonotonic effect on the amount of DNA ejected. There exists an optimal concentration at which the minimum amount of DNA is ejected from the virus. At lower or higher concentrations, more DNA is ejected from the capsid. We propose that this phenomenon is the result of DNA overcharging by Mg+2 multivalent counterions. As Mg+2 concentration increases from zero, the net charge of DNA changes from negative to positive. The optimal inhibition corresponds to the Mg+2 concentration where DNA is neutral. At lower/higher concentrations, DNA genome is charged. It prefers to be in solution to lower its electrostatic self-energy, which consequently leads to an increase in DNA ejection. By fitting our theory to available experimental data, the strength of DNA-DNA short range attraction energies, mediated by Mg+2, is found to be -0.004 kBT per nucleotide base. This and other fitted parameters agree well with known values from other experiments and computer simulations. The parameters are also in agreement qualitatively with values for tri- and tetravalent counterions.

  5. Inhibition of DNA ejection from bacteriophage by Mg^+2 counterions

    NASA Astrophysics Data System (ADS)

    Lee, Seil; Tran, Cathy V.; Nguyen, Toan T.

    2009-03-01

    The problem of inhibiting viral DNA ejection from bacteriophages by multivalent counterions, especially Mg^+2 counterions, is studied. Experimentally, it is known that MgSO4 salt has a strong and non-monotonic effect on the amount of DNA ejected. There exists an optimal concentration at which the least DNA is ejected from the virus. At lower or higher concentrations, more DNA is ejected from the capsid. We propose that this phenomenon is the result of DNA overcharging by Mg^+2 multivalent counterions. As Mg^+2 concentration increases from zero, DNA net charge changes from negative to positive. The optimal inhibition corresponds to the Mg^+2 concentration where DNA is neutral. At lower/higher concentrations, DNA genome is charged. It prefers to be in solution to lower its electrostatic self-energy, which consequently leads to an increase in DNA ejection. Our theory fits experimental data well. The strength of DNA-DNA short range attraction, mediated by Mg^+2, is found to be -0.003 kBT per nucleotide base.

  6. DNA-DNA interaction inside bacteriophage modulated by multivalent counterions

    NASA Astrophysics Data System (ADS)

    Nguyen, Toan; Lee, Seil; Le, Tung

    2010-03-01

    The problem of inhibiting viral DNA ejection from bacteriophages by multivalent counterions, especially Mg^+2 counterions, is studied. Experimentally, it is known that MgSO4 salt has a strong and non-monotonic effect on the amount of DNA ejected. There exists an optimal concentration at which the least DNA is ejected from the virus. At lower or higher concentrations, more DNA is ejected from the capsid. We propose that this phenomenon is the result of DNA overcharging by Mg^+2 multivalent counterions. As Mg^+2 concentration increases from zero, DNA net charge changes from negative to positive. The optimal inhibition corresponds to the Mg^+2 concentration where DNA is neutral. At lower/higher concentrations, DNA genome is charged. It prefers to be in solution to lower its electrostatic self-energy, which consequently leads to an increase in DNA ejection. Our theory fits experimental data well. The strength of DNA - DNA short range attraction, mediated by Mg^+2, is found to be - 0.003 kBT per nucleotide base. Results from expanded ensemble Monte-Carlo simulation of hexagonal DNA bundles are discussed and are shown to be in good agreement with theoretical results.

  7. The allosteric switching mechanism in bacteriophage MS2.

    PubMed

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

    2016-07-21

    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. PMID:27448905

  8. Novel N4 Bacteriophages Prevail in the Cold Biosphere.

    PubMed

    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. PMID:26025897

  9. Characterizing Aquifer Heterogeneity Using Bacterial and Bacteriophage Tracers.

    PubMed

    Flynn, Raymond M; Mallèn, German; Engel, Marion; Ahmed, Ashraf; Rossi, Pierre

    2015-09-01

    Gravel aquifers act as important potable water sources in central western Europe, yet they are subject to numerous contamination pressures. Compositional and textural heterogeneity makes protection zone delineation around groundwater supplies in these units challenging; artificial tracer testing aids characterization. This paper reappraises previous tracer test results in light of new geological and microbiological data. Comparative passive gradient testing, using a fluorescent solute (Uranine), virus (H40/1 bacteriophage), and comparably sized bacterial tracers and , was used to investigate a calcareous gravel aquifer's ability to remove microbiological contaminants at a test site near Munich, Germany. Test results revealed relative recoveries could exceed those of H40/1 at monitoring wells, 10 m and 20 m from an injection well, by almost four times; recoveries varied by a factor of up to three between wells. Application of filtration theory suggested greater attenuation of H40/1 relative to similarly charged occurred due to differences in microorganism size, while estimated collision efficiencies appeared comparable. By contrast, more positively charged experienced greater attenuation at one monitoring point, while lower attenuation rates at the second location indicated the influence of geochemical heterogeneity. Test findings proved consistent with observations from nearby fresh outcrops that suggested thin open framework gravel beds dominated mass transport in the aquifer, while discrete intervals containing stained clasts reflect localized geochemical heterogeneity. Study results highlight the utility of reconciling outcrop observations with artificial tracer test responses, using microbiological tracers with well-defined properties, to characterize aquifer heterogeneity. PMID:26436262

  10. Antimicrobial bacteriophage-derived proteins and therapeutic applications

    PubMed Central

    Roach, Dwayne R; Donovan, David M

    2015-01-01

    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 (phages) are parasites that invade the cells of virtually all known bacteria. Phages reproduce by utilizing the host cell's machinery to replicate viral proteins and genomic material, generally damaging and killing the cell in the process. Thus, phage can be exploited therapeutically as bacteriolytic agents against bacteria. Furthermore, understanding of the molecular processes involved in the viral life cycle, particularly the entry and cell lysis steps, has led to the development of viral proteins as antibacterial agents. Here we review the current preclinical state of using phage-derived endolysins, virion-associated peptidoglycan hydrolases, polysaccharide depolymerases, and holins for the treatment of bacterial infection. The scope of this review is a focus on the viral proteins that have been assessed for protective effects against human pathogenic bacteria in animal models of infection and disease. PMID:26442196

  11. Sequence of the Genome of Salmonella Bacteriophage P22

    PubMed Central

    Byl, Carolyn Vander; Kropinski, Andrew M.

    2000-01-01

    The sequence of the nonredundant region of the Salmonella enterica serovar Typhimurium temperate, serotype-converting bacteriophage P22 has been completed. The genome is 41,724 bp with an overall moles percent GC content of 47.1%. Numerous examples of potential integration host factor and C1-binding sites were identified in the sequence. In addition, five potential rho-independent terminators were discovered. Sixty-five genes were identified and annotated. While many of these had been described previously, we have added several new ones, including the genes involved in serotype conversion and late control. Two of the serotype conversion gene products show considerable sequence relatedness to GtrA and -B from Shigella phages SfII, SfV, and SfX. We have cloned the serotype-converting cassette (gtrABC) and demonstrated that it results in Salmonella serovar Typhimurium LT2 cells which express antigen O1. Many of the putative proteins show sequence relatedness to proteins from a great variety of other phages, supporting the hypothesis that this phage has evolved through the recombinational exchange of genetic information with other viruses. PMID:11053393

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2016-09-01

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

  14. [Bacteriophage λ: electrostatic properties of the genome and its elements].

    PubMed

    Krutinina, G G; Krutinin, E A; Kamzolova, S G; Osypov, A A

    2015-01-01

    Bacteriophage λ is a classical model object in molecular biology, but little is still known on the physical properties of its DNA and regulatory elements. A study was made of the electrostatic properties of phage λ DNA and regulatory elements. A global electrostatic potential distribution along the phage genome was found to be nonuniform with main regulatory elements being located in a limited region with a high potential. The RNA polymerase binding frequency on the linearized phage chromosome directly correlates with its local potential. Strong promoters of the phage and its host Escherichia coli have distinct electrostatic upstream elements, which differ in nucleotide sequence. Attachment and recombination sites of phage λ and its host have a higher potential, which possibly facilitates their recognition by integrase. Phage λ and host Rho-independent terminators have a symmetrical M-shaped potential profile, which only slightly depends on the annotated terminator palindrome length, and occur in a region with a substantially higher potential, which may cause polymerase retention, facilitating the formation of a terminator hairpin in RNA. It was concluded that virtually all elements of phage λ genome have potential distribution specifics, which are related to their structural properties and may play a role in their biological function. The global potential distribution along the phage genome reflects the architecture of the regulation of its transcription and integration in the host genome. PMID:26107891

  15. Genetic and Immunological Studies of Bacteriophage T4 Thymidylate Synthetase

    PubMed Central

    Krauss, S. W.; Stollar, B. D.; Friedkin, M.

    1973-01-01

    Thymidylate synthetase, which appears after infection of Escherichia coli with bacteriophage T4, has been partially purified. The phage enzyme is immunologically distinct from the host enzyme and has a molecular weight of 50,000 in comparison to 68,000 for the host enzyme. A system has been developed to characterize T4 td mutants previously known to have impaired expression of phage thymidylate synthetase. For this system, an E. coli host lacking thymidylate synthetase was isolated. Known genetic suppressors were transduced into this host. The resulting isogenic hosts were infected with phage T4 td mutants. The specific activities and amounts of cross-reacting material induced by several different types of phage mutants under conditions of suppression or non-suppression have been examined. The results show that the phage carries the structural gene specifying the thymidylate synthetase which appears after phage infection, and that the combination of plaque morphology, enzyme activity assays, and an assay for immunologically cross-reacting material provides a means for identifying true amber mutants of the phage gene. Images PMID:4575286

  16. Assembly of Hybrid Bacteriophage Qβ Virus-Like Particles

    PubMed Central

    Brown, Steven D.; Fiedler, Jason D.; Finn, M.G.

    2009-01-01

    Bacteriophage Qβ coat protein forms uniform virus-like particles when expressed recombinantly in a variety of organisms. We have inserted the IgG-binding Z domain at the carboxy terminus of the coat protein and coexpressed this chimeric subunit with native coat protein to create hybrid, IgG-binding virus-like particles. Extracellular osmolytes were found to have an effect on the incorporation efficiency of fusion proteins into VLPs in E. coli when a carbenicillin, but not a kanamycin, selection marker was used. The addition of sucrose to the growth media decreased incorporation efficiency; the osmoprotectant glycine betaine eliminated this effect. The decrease in efficiency was not observed when carbenicillin was omitted from the final expression culture. The addition of sodium chloride instead of sucrose gave rise to particles with a larger number of fusion proteins than the standard conditions. These results illustrate that cellular conditions should be taken into account even in apparently simple systems when natural or engineered protein nanoparticles are made. PMID:19848414

  17. Comparative genomic analysis of ten Streptococcus pneumoniae temperate bacteriophages.

    PubMed

    Romero, Patricia; Croucher, Nicholas J; Hiller, N Luisa; Hu, Fen Z; Ehrlich, Garth D; Bentley, Stephen D; García, Ernesto; Mitchell, Tim J

    2009-08-01

    Streptococcus pneumoniae is an important human pathogen that often carries temperate bacteriophages. As part of a program to characterize the genetic makeup of prophages associated with clinical strains and to assess the potential roles that they play in the biology and pathogenesis in their host, we performed comparative genomic analysis of 10 temperate pneumococcal phages. All of the genomes are organized into five major gene clusters: lysogeny, replication, packaging, morphogenesis, and lysis clusters. All of the phage particles observed showed a Siphoviridae morphology. The only genes that are well conserved in all the genomes studied are those involved in the integration and the lysis of the host in addition to two genes, of unknown function, within the replication module. We observed that a high percentage of the open reading frames contained no similarities to any sequences catalogued in public databases; however, genes that were homologous to known phage virulence genes, including the pblB gene of Streptococcus mitis and the vapE gene of Dichelobacter nodosus, were also identified. Interestingly, bioinformatic tools showed the presence of a toxin-antitoxin system in the phage phiSpn_6, and this represents the first time that an addition system in a pneumophage has been identified. Collectively, the temperate pneumophages contain a diverse set of genes with various levels of similarity among them. PMID:19502408

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

    PubMed

    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.

  19. Classification and quantification of bacteriophage taxa in human gut metagenomes

    PubMed Central

    Waller, Alison S; Yamada, Takuji; Kristensen, David M; Kultima, Jens Roat; Sunagawa, Shinichi; Koonin, Eugene V; Bork, Peer

    2014-01-01

    Bacteriophages have key roles in microbial communities, to a large extent shaping the taxonomic and functional composition of the microbiome, but data on the connections between phage diversity and the composition of communities are scarce. Using taxon-specific marker genes, we identified and monitored 20 viral taxa in 252 human gut metagenomic samples, mostly at the level of genera. On average, five phage taxa were identified in each sample, with up to three of these being highly abundant. The abundances of most phage taxa vary by up to four orders of magnitude between the samples, and several taxa that are highly abundant in some samples are absent in others. Significant correlations exist between the abundances of some phage taxa and human host metadata: for example, ‘Group 936 lactococcal phages' are more prevalent and abundant in Danish samples than in samples from Spain or the United States of America. Quantification of phages that exist as integrated prophages revealed that the abundance profiles of prophages are highly individual-specific and remain unique to an individual over a 1-year time period, and prediction of prophage lysis across the samples identified hundreds of prophages that are apparently active in the gut and vary across the samples, in terms of presence and lytic state. Finally, a prophage–host network of the human gut was established and includes numerous novel host–phage associations. PMID:24621522

  20. Functional eukaryotic nuclear localization signals are widespread in terminal proteins of bacteriophages.

    PubMed

    Redrejo-Rodríguez, Modesto; Muñoz-Espín, Daniel; Holguera, Isabel; Mencía, Mario; Salas, Margarita

    2012-11-01

    A number of prokaryotic proteins have been shown to contain nuclear localization signals (NLSs), although its biological role remains sometimes unclear. Terminal proteins (TPs) of bacteriophages prime DNA replication and become covalently linked to the genome ends. We predicted NLSs within the TPs of bacteriophages from diverse families and hosts and, indeed, the TPs of Φ29, Nf, PRD1, Bam35, and Cp-1, out of seven TPs tested, were found to localize to the nucleus when expressed in mammalian cells. Detailed analysis of Φ29 TP led us to identify a bona fide NLS within residues 1-37. Importantly, gene delivery into the eukaryotic nucleus is enhanced by the presence of Φ29 TP attached to the 5' DNA ends. These findings show a common feature of TPs from diverse bacteriophages targeting the eukaryotic nucleus and suggest a possible common function by facilitating the horizontal transfer of genes between prokaryotes and eukaryotes.

  1. Isolation and characterization of a bacteriophage for bacillus licheniformis A5

    SciTech Connect

    Schreier, H.J.; Vonada, E.K.; Yasbin, R.E.; Bernlohr, R.W.

    1982-01-01

    The isolation of a virulent bacteriophage for Bacillus licheniformis A5 is reported. This bacteriophage, designated NLP-1, has an icosahedral head 100 nm in diameter and a contractible tail with a maximum length of 130 nm. Its DNA has a density of 1.741 g/cm/sup 3/ and a T/sub m/ of 78.4/sup 0/C. Base composition analysis showed that thymine is absent and is replaced by hydroxymethyluracil. NLP-1 appears to belong to the Bacillus group of bacteriophages that includes SP01 and SP82. It will infect B. cereus T and B. brevis 8185, but will not infect B. subtilis W23 or 168.

  2. Double-stranded DNA organization in bacteriophage heads: An alternative toroid-based model

    SciTech Connect

    Hud, N.V.

    1995-10-01

    Studies of the organization of double-stranded DNA within bacteriophage heads during the past four decades have produced a wealth of data. However, despite the presentation of numerous models, the true organization of DNA within phage heads remains unresolved. The observations of toroidal DNA structures in electron micrographs of phage lysates have long been cited as support for the organization of DNA in a spool-like fashion. This particular model, like all other models, has not been found to be consistent with all available data. Recently, the authors proposed that DNA within toroidal condensates produced in vitro is organized in a manner significantly different from that suggested by the spool model. This new toroid model has allowed the development of an alternative model for DNA organization within bacteriophage heads that is consistent with a wide range of biophysical data. Here the authors propose that bacteriophage DNA is packaged in a toroid that is folded into a highly compact structure.

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

    NASA Astrophysics Data System (ADS)

    Abramov, Gili; Morag, Omry; Goldbourt, Amir

    2015-04-01

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

  4. Stimulation of Innate and Adaptive Immunity by Using Filamentous Bacteriophage fd Targeted to DEC-205

    PubMed Central

    D'Apice, Luciana; Costa, Valerio; Sartorius, Rossella; Trovato, Maria; Aprile, Marianna; De Berardinis, Piergiuseppe

    2015-01-01

    The filamentous bacteriophage fd, codisplaying antigenic determinants and a single chain antibody fragment directed against the dendritic cell receptor DEC-205, is a promising vaccine candidate for its safety and its ability to elicit innate and adaptive immune response in absence of adjuvants. By using a system vaccinology approach based on RNA-Sequencing (RNA-Seq) analysis, we describe a relevant gene modulation in dendritic cells pulsed with anti-DEC-205 bacteriophages fd. RNA-Seq data analysis indicates that the bacteriophage fd virions are sensed as a pathogen by dendritic cells; they activate the danger receptors that trigger an innate immune response and thus confer a strong adjuvanticity that is needed to obtain a long-lasting adaptive immune response. PMID:26380324

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

    PubMed

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

    2014-03-01

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

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

    PubMed

    Abramov, Gili; Morag, Omry; Goldbourt, Amir

    2015-04-01

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

  7. Genetic analysis of the cIII gene of bacteriophage HK022.

    PubMed Central

    Kornitzer, D; Altuvia, S; Oppenheim, A B

    1991-01-01

    The cIII gene product of lambdoid bacteriophages promotes lysogeny by stabilizing the phage-encoded CII protein, a transcriptional activator of the repressor and integrase genes. Previous works showed that the synthesis of the bacteriophage lambda CIII protein has specific translational requirements imposed by the structure of the mRNA. To gain insight into the mRNA structure and its role in regulating cIII translation, we undertook a mutational analysis of the cIII gene of the related bacteriophage HK022. Our data support the hypothesis that in HK022, as in lambda, translation initiation requires a specific mRNA structure. In addition, we found that translation of HK022 cIII, like that of lambda, is strongly reduced in a host deficient in the endonuclease RNase III. Images PMID:1824768

  8. Stimulation of Innate and Adaptive Immunity by Using Filamentous Bacteriophage fd Targeted to DEC-205.

    PubMed

    D'Apice, Luciana; Costa, Valerio; Sartorius, Rossella; Trovato, Maria; Aprile, Marianna; De Berardinis, Piergiuseppe

    2015-01-01

    The filamentous bacteriophage fd, codisplaying antigenic determinants and a single chain antibody fragment directed against the dendritic cell receptor DEC-205, is a promising vaccine candidate for its safety and its ability to elicit innate and adaptive immune response in absence of adjuvants. By using a system vaccinology approach based on RNA-Sequencing (RNA-Seq) analysis, we describe a relevant gene modulation in dendritic cells pulsed with anti-DEC-205 bacteriophages fd. RNA-Seq data analysis indicates that the bacteriophage fd virions are sensed as a pathogen by dendritic cells; they activate the danger receptors that trigger an innate immune response and thus confer a strong adjuvanticity that is needed to obtain a long-lasting adaptive immune response.

  9. [Bacteriophage lambda:lux: design and expression of bioluminescence in E. coli cells].

    PubMed

    Duzhiĭ, D E; Zavil'gel'skiĭ, G B

    1994-01-01

    The bacteriophages lambda:lux and lambda:luxAB have been constructed by ligation of phage arms generated by BamHI or SalGI restriction endonucleases digestion of EMBL4 to BamHI digested plasmid pF1 lux+ or to SalGI digested plasmid pF2 lambda:luxA+B+. Cells of Escherichia coli prototrophic strain Cs were infected with lambda:lux or lambda:luxAB and intensity of bioluminiscence of the samples registered at different time intervals determined. The signal of bioluminiscence was first detected 15 min after infection and its level increased exponentially thereafter demonstrating replication of the lambda:lux bacteriophages. We have used the recombinant lambda:luxAB bacteriophage to detect the enteric indicator bacteria without enrichment in 15 min, provided that they are present at levels higher than 10(4).

  10. Structure of the bacteriophage T4 long tail fiber receptor-binding tip

    PubMed Central

    Bartual, Sergio G.; Otero, José M.; Garcia-Doval, Carmela; Llamas-Saiz, Antonio L.; Kahn, Richard; Fox, Gavin C.; van Raaij, Mark J.

    2010-01-01

    Bacteriophages are the most numerous organisms in the biosphere. In spite of their biological significance and the spectrum of potential applications, little high-resolution structural detail is available on their receptor-binding fibers. Here we present the crystal structure of the receptor-binding tip of the bacteriophage T4 long tail fiber, which is highly homologous to the tip of the bacteriophage lambda side tail fibers. This structure reveals an unusual elongated six-stranded antiparallel beta-strand needle domain containing seven iron ions coordinated by histidine residues arranged colinearly along the core of the biological unit. At the end of the tip, the three chains intertwine forming a broader head domain, which contains the putative receptor interaction site. The structure reveals a previously unknown beta-structured fibrous fold, provides insights into the remarkable stability of the fiber, and suggests a framework for mutations to expand or modulate receptor-binding specificity. PMID:21041684

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

    PubMed

    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(4) PFU/mL, medium: 10(4)-10(7) PFU/mL, and high: >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.

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

    PubMed

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

    2011-01-01

    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(4) PFU/mL, medium: 10(4)-10(7) PFU/mL, and high: >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. PMID:21789469

  13. Infrared: Beyond the Visible

    NASA Video Gallery

    Infrared: Beyond the Visible, is a fast, fun look at why infrared light matters to astronomy, and what the Webb Space Telescope will search for once it's in orbit. Caption file available at: http:/...

  14. Learning from Bacteriophages - Advantages and Limitations of Phage and Phage-Encoded Protein Applications

    PubMed Central

    Drulis-Kawa, Zuzanna; Majkowska-Skrobek, Grażyna; Maciejewska, Barbara; Delattre, Anne-Sophie; Lavigne, Rob

    2012-01-01

    The emergence of bacteria resistance to most of the currently available antibiotics has become a critical therapeutic problem. The bacteria causing both hospital and community-acquired infections are most often multidrug resistant. In view of the alarming level of antibiotic resistance between bacterial species and difficulties with treatment, alternative or supportive antibacterial cure has to be developed. The presented review focuses on the major characteristics of bacteriophages and phage-encoded proteins affecting their usefulness as antimicrobial agents. We discuss several issues such as mode of action, pharmacodynamics, pharmacokinetics, resistance and manufacturing aspects of bacteriophages and phage-encoded proteins application. PMID:23305359

  15. Superinfection in Bacteriophage S13 and Determination of the Number of Bacteriophage Particles Which Can Function in an Infected Cell

    PubMed Central

    Tessman, Ethel S.; Borrás, Maria-Teresa; Sun, Iris L.

    1971-01-01

    Bacteriophage S13 shows exclusion of superinfecting homologous phage, but the exclusion is only partial. The superinfecting phage can form infectious replicative form deoxyribonucleic acid (RF), can direct protein synthesis, and can form progeny particles even at a superinfection time as late as 60 min after the first infection. Exclusion is also only partial for the closely related phage φX174. Seven min after the first infection, the exclusion mechanism begins to operate, requiring continuous phage-specified protein synthesis. The gene A protein (required for synthesis of progeny RF) appears to be involved in the exclusion mechanism. In superinfection experiments, it was found that at least 40 phage particles per cell can replicate and can carry out protein synthesis, though the number of sites for binding of RF to the membrane is only about 15 per cell. The results suggest that attachment of RF to a binding site is not required for protein synthesis. Evidence is presented that non-attached parental RF can serve as a template for single-stranded deoxyribonucleic acid synthesis. PMID:4937062

  16. Two bacteriophages which utilize a new Escherichia coli major outer membrane protein as part of their receptor.

    PubMed

    Chai, T J; Foulds, J

    1978-07-01

    Escherichia coli strain JF694 contains a new major outer membrane protein which we have called protein E (J. Foulds, and T. Chai, J. Bacteriol. 133:1478-1483). Two new bacteriophages, TC45 and TC23, were isolated that require the presence of protein E in the outer membrane of host cells for growth. Both of these bacteriophages have a morphology similar to T-even bacteriophages but are distinct in properties such as plaque morphology, buoyant density, and burst size. Although strain JF694, containing protein E, adsorbs bacteriophage TC45 efficiently, cells killed with heat or chloroform are unable to inactivate this bacteriophage. Purified protein E either in the presence or absence of additional probable cofactors such as lipopolysaccharide was also unable to inactivate bacteriophage TC45. Both bacteriophages probably use protein E as at least part of their receptor but require, in addition, other outer membrane components or a specific orientation or organization of this protein in the outer membrane.

  17. Enumeration and diversity of campylobacters and bacteriophages isolated during the rearing cycles of free-range and organic chickens.

    PubMed

    El-Shibiny, A; Connerton, P L; Connerton, I F

    2005-03-01

    Campylobacters and Campylobacter-specific bacteriophages were isolated and enumerated during the rearing cycle of free-range (56 days) and organic chickens (73 days) at 3-day intervals from hatching until slaughter. In both flocks Campylobacter jejuni was the initial colonizer but Campylobacter coli was detected more frequently from 5 weeks of age. The diversity of the Campylobacter isolates was examined by pulsed-field gel electrophoresis of SmaI-digested genomic DNA and antimicrobial resistance typing. Bacteriophages were isolated from 51% (19 of 37 birds) of Campylobacter-positive organic birds (log10 2.5 to log10 5.7 PFU/g of cecal contents). The bacteriophages were all typical group III Campylobacter bacteriophages in terms of genomic size but could be characterized in terms of their host range and placed into five different groups. In contrast to the organic birds, anti-Campylobacter activity (bacteriocin-like) was observed in 26% (10 of 38 birds) of Campylobacter-positive free-range birds, and only one bacteriophage was isolated. Appearance of either bacteriophages or anti-Campylobacter activity was associated with changes in the levels of colonization and the predominant genotypes and species isolated. The frequency and potential influence of naturally occurring bacteriophages and/or inhibitory substances on the diversity and fluctuations of populations of campylobacters have not previously been reported in either free-range or organic chickens.

  18. Isolation and characterization of glacier VMY22, a novel lytic cold-active bacteriophage of Bacillus cereus.

    PubMed

    Ji, Xiuling; Zhang, Chunjing; Fang, Yuan; Zhang, Qi; Lin, Lianbing; Tang, Bing; Wei, Yunlin

    2015-02-01

    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 pH 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.

  19. In vitro design of a novel lytic bacteriophage cocktail with therapeutic potential against organisms causing diabetic foot infections.

    PubMed

    Mendes, João J; Leandro, Clara; Mottola, Carla; Barbosa, Raquel; Silva, Filipa A; Oliveira, Manuela; Vilela, Cristina L; Melo-Cristino, José; Górski, Andrzej; Pimentel, Madalena; São-José, Carlos; Cavaco-Silva, Patrícia; Garcia, Miguel

    2014-08-01

    In patients with diabetes mellitus, foot infections pose a significant risk. These are complex infections commonly caused by Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii, all of which are potentially susceptible to bacteriophages. Here, we characterized five bacteriophages that we had determined previously to have antimicrobial and wound-healing potential in chronic S. aureus, P. aeruginosa and A. baumannii infections. Morphological and genetic features indicated that the bacteriophages were lytic members of the family Myoviridae or Podoviridae and did not harbour any known bacterial virulence genes. Combinations of the bacteriophages had broad host ranges for the different target bacterial species. The activity of the bacteriophages against planktonic cells revealed effective, early killing at 4 h, followed by bacterial regrowth to pre-treatment levels by 24 h. Using metabolic activity as a measure of cell viability within established biofilms, we found significant cell impairment following bacteriophage exposure. Repeated treatment every 4 h caused a further decrease in cell activity. The greatest effects on both planktonic and biofilm cells occurred at a bacteriophage : bacterium input multiplicity of 10. These studies on both planktonic cells and established biofilms allowed us to better evaluate the effects of a high input multiplicity and a multiple-dose treatment protocol, and the findings support further clinical development of bacteriophage therapy.

  20. Simultaneous Identification and Susceptibility Determination to Multiple Antibiotics of Staphylococcus aureus by Bacteriophage Amplification Detection Combined with Mass Spectrometry.

    PubMed

    Rees, Jon C; Pierce, Carrie L; Schieltz, David M; Barr, John R

    2015-07-01

    The continued advance of antibiotic resistance in clinically relevant bacterial strains necessitates the development and refinement of assays that can rapidly and cost-effectively identify bacteria and determine their susceptibility to a panel of antibiotics. A methodology is described herein that exploits the specificity and physiology of the Staphylococci bacteriophage K to identify Staphylococcus aureus (S. aureus) and determine its susceptibility to clindamycin and cefoxitin. The method uses liquid chromatography-mass spectrometry to monitor the replication of bacteriophage after it is used to infect samples thought to contain S. aureus. Amplification of bacteriophage K indicates the sample contains S. aureus, for it is only in the presence of a suitable host that bacteriophage K can amplify. If bacteriophage amplification is detected in samples containing the antibiotics clindamycin or cefoxitin, the sample is deemed to be resistant to these antibiotics, respectively, for bacteriophage can only amplify in a viable host. Thus, with a single work flow, S. aureus can be detected in an unknown sample and susceptibility to clindamycin and cefoxitin can be ascertained. This Article discusses implications for the use of bacteriophage amplification in the clinical laboratory.

  1. Tryptophan contributions to the unusual circular dichroism of fd bacteriophage.

    PubMed

    Arnold, G E; Day, L A; Dunker, A K

    1992-09-01

    The circular dichroism (CD) spectrum of fd bacteriophage has a deep minimum at 222 nm characteristic of highly alpha-helical protein, but there is a shoulder at 208 nm rather than a minimum, with a 222/208-nm amplitude ratio near 1.5 rather than near 1. Oxidation of fd phage with the tryptophan reagent N-bromosuccinimide (NBS) changes the ratio. In this report, the NBS titration of fd is followed by CD and three other spectroscopies, the results of which yield an explanation of the unusual CD spectrum. Absorbance, fluorescence, and Raman data show the oxidation to have two phases, the first of which involves the destruction of tryptophan and the second, tryptophan and tyrosine. Raman spectra reveal the invariance of an environmentally-sensitive tyrosine Fermi resonance doublet during the first oxidative phase. Raman spectra also show that little or no change of alpha-helicity occurs in the first or second oxidation phase, although very slight changes in the helix parameters might be occurring. Concurrent with the destruction of tryptophan during the first phase is the appearance in CD difference spectra ([theta]NBS-treated fd - [theta]native fd) of positive maxima at 208-210 nm and negative maxima at 224 nm, with crossovers at 217 nm. Enormous difference ellipticities, per oxidized subunit of 50 amino acids, of +490,000 +/- 80,000 deg cm2 dmol-1 at 208 nm and -520,000 +/- 110,000 deg cm2 dmol-1 at 224 nm have been derived from the data.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Antimicrobial Activity of Bacteriophage Endolysin Produced in Nicotiana benthamiana Plants.

    PubMed

    Kovalskaya, Natalia; Foster-Frey, Juli; Donovan, David M; Bauchan, Gary; Hammond, Rosemarie W

    2016-01-01

    The increasing spread of antibiotic-resistant pathogens has raised the interest in alternative antimicrobial treatments. In our study, the functionally active gram-negative bacterium bacteriophage CP933 endolysin was produced in Nicotiana benthamiana plants by a combination of transient expression and vacuole targeting strategies, and its antimicrobial activity was investigated. Expression of the cp933 gene in E. coli led to growth inhibition and lysis of the host cells or production of trace amounts of CP933. Cytoplasmic expression of the cp933 gene in plants using Potato virus X-based transient expression vectors (pP2C2S and pGR107) resulted in death of the apical portion of experimental plants. To protect plants against the toxic effects of the CP933 protein, the cp933 coding region was fused at its Nterminus to an N-terminal signal peptide from the potato proteinase inhibitor I to direct CP933 to the delta-type vacuoles. Plants producing the CP933 fusion protein did not exhibit the severe toxic effects seen with the unfused protein and the level of expression was 0.16 mg/g of plant tissue. Antimicrobial assays revealed that, in contrast to gram-negative bacterium E. coli (BL21(DE3)), the gram-positive plant pathogenic bacterium Clavibacter michiganensis was more susceptible to the plant-produced CP933, showing 18% growth inhibition. The results of our experiments demonstrate that the combination of transient expression and protein targeting to the delta vacuoles is a promising approach to produce functionally active proteins that exhibit toxicity when expressed in plant cells. PMID:26403819

  3. Mobile CRISPR/Cas-Mediated Bacteriophage Resistance in Lactococcus lactis

    PubMed Central

    Millen, Anne M.; Horvath, Philippe; Boyaval, Patrick; Romero, Dennis A.

    2012-01-01

    Lactococcus lactis is a biotechnological workhorse for food fermentations and potentially therapeutic products and is therefore widely consumed by humans. It is predominantly used as a starter microbe for fermented dairy products, and specialized strains have adapted from a plant environment through reductive evolution and horizontal gene transfer as evidenced by the association of adventitious traits with mobile elements. Specifically, L. lactis has armed itself with a myriad of plasmid-encoded bacteriophage defensive systems to protect against viral predation. This known arsenal had not included CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated proteins), which forms a remarkable microbial immunity system against invading DNA. Although CRISPR/Cas systems are common in the genomes of closely related lactic acid bacteria (LAB), none was identified within the eight published lactococcal genomes. Furthermore, a PCR-based search of the common LAB CRISPR/Cas systems (Types I and II) in 383 industrial L. lactis strains proved unsuccessful. Here we describe a novel, Type III, self-transmissible, plasmid-encoded, phage-interfering CRISPR/Cas discovered in L. lactis. The native CRISPR spacers confer resistance based on sequence identity to corresponding lactococcal phage. The interference is directed at phages problematic to the dairy industry, indicative of a responsive system. Moreover, targeting could be modified by engineering the spacer content. The 62.8-kb plasmid was shown to be conjugally transferrable to various strains. Its mobility should facilitate dissemination within microbial communities and provide a readily applicable system to naturally introduce CRISPR/Cas to industrially relevant strains for enhanced phage resistance and prevention against acquisition of undesirable genes. PMID:23240053

  4. A bacteriophage detection tool for viability assessment of Salmonella cells.

    PubMed

    Fernandes, E; Martins, V C; Nóbrega, C; Carvalho, C M; Cardoso, F A; Cardoso, S; Dias, J; Deng, D; Kluskens, L D; Freitas, P P; Azeredo, J

    2014-02-15

    Salmonellosis, one of the most common food and water-borne diseases, has a major global health and economic impact. Salmonella cells present high infection rates, persistence over inauspicious conditions and the potential to preserve virulence in dormant states when cells are viable but non-culturable (VBNC). These facts are challenging for current detection methods. Culture methods lack the capacity to detect VBNC cells, while biomolecular methods (e.g. DNA- or protein-based) hardly distinguish between dead innocuous cells and their viable lethal counterparts. This work presents and validates a novel bacteriophage (phage)-based microbial detection tool to detect and assess Salmonella viability. Salmonella Enteritidis cells in a VBNC physiological state were evaluated by cell culture, flow-cytometry and epifluorescence microscopy, and further assayed with a biosensor platform. Free PVP-SE1 phages in solution showed the ability to recognize VBNC cells, with no lysis induction, in contrast to the minor recognition of heat-killed cells. This ability was confirmed for immobilized phages on gold surfaces, where the phage detection signal follows the same trend of the concentration of viable plus VBNC cells in the sample. The phage probe was then tested in a magnetoresistive biosensor platform allowing the quantitative detection and discrimination of viable and VBNC cells from dead cells, with high sensitivity. Signals arising from 3 to 4 cells per sensor were recorded. In comparison to a polyclonal antibody that does not distinguish viable from dead cells, the phage selectivity in cell recognition minimizes false-negative and false-positive results often associated with most detection methods.

  5. DNA damage under simulated extraterrestrial conditions in bacteriophage T7

    NASA Astrophysics Data System (ADS)

    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

  6. Switching the polarity of a bacteriophage integration system.

    PubMed

    Smith, Matthew C A; Till, Rob; Smith, Margaret C M

    2004-03-01

    During lysogenic growth many temperate bacteriophage genomes are integrated into the host's chromosome and efficient integration and excision are therefore an essential part of the phage life cycle. The Streptomyces phage phiC31 encodes an integrase related to the resolvase/invertases and is evolutionarily and mechanistically distinct from the integrase of phage lambda. We show that during phiC31 integration the polarity of the recombination sites, attB and attP, is dependent on the sequences of the two base pairs (bp) where crossover occurs. A loss or switch in polarity of the recombination sites can occur by mutation of this dinucleotide, leading to incorrectly joined products. The properties of the mutant sites implies that phiC31 integrase interacts symmetrically with the substrates, which during synapsis can align apparently freely in either of two alternative forms that lead to correct or incorrect joining of products. Analysis of the topologies of the reaction products provided evidence that integrase can synapse and activate strand exchange even when recombinant products cannot form due to mismatches at the crossover site. The topologies of the recombination products are complex and indicative of multiple pathways to product formation. The efficiency of integration of a phiC31 derivative, KC859, into an attB site with switched polarity was assayed in vivo and shown to be no different from integration into a wild-type attB. Thus neither the host nor KC859 express a factor that influences the alignment of the recombination sites at synapsis.

  7. Dynamics of bacteriophage genome ejection in vitro and in vivo

    NASA Astrophysics Data System (ADS)

    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.

  8. Bacteriophage Amplification-Coupled Detection and Identification of Bacterial Pathogens

    NASA Astrophysics Data System (ADS)

    Cox, Christopher R.; Voorhees, Kent J.

    Current methods of species-specific bacterial detection and identification are complex, time-consuming, and often require expensive specialized equipment and highly trained personnel. Numerous biochemical and genotypic identification methods have been applied to bacterial characterization, but all rely on tedious microbiological culturing practices and/or costly sequencing protocols which render them impractical for deployment as rapid, cost-effective point-of-care or field detection and identification methods. With a view towards addressing these shortcomings, we have exploited the evolutionarily conserved interactions between a bacteriophage (phage) and its bacterial host to develop species-specific detection methods. Phage amplification-coupled matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS) was utilized to rapidly detect phage propagation resulting from species-specific in vitro bacterial infection. This novel signal amplification method allowed for bacterial detection and identification in as little as 2 h, and when combined with disulfide bond reduction methods developed in our laboratory to enhance MALDI-TOF-MS resolution, was observed to lower the limit of detection by several orders of magnitude over conventional spectroscopy and phage typing methods. Phage amplification has been combined with lateral flow immunochromatography (LFI) to develop rapid, easy-to-operate, portable, species-specific point-of-care (POC) detection devices. Prototype LFI detectors have been developed and characterized for Yersinia pestis and Bacillus anthracis, the etiologic agents of plague and anthrax, respectively. Comparable sensitivity and rapidity was observed when phage amplification was adapted to a species-specific handheld LFI detector, thus allowing for rapid, simple, POC bacterial detection and identification while eliminating the need for bacterial culturing or DNA isolation and amplification techniques.

  9. Novel DNA packaging recognition in the unusual bacteriophage N15

    SciTech Connect

    Feiss, Michael; Geyer, Henriette; Klingberg, Franco; Moreno, Norma; Forystek, Amanda; Maluf, Nasib Karl; Sippy, Jean

    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.

  10. Combined treatment of Pseudomonas aeruginosa biofilms with bacteriophages and chlorine.

    PubMed

    Zhang, Yanyan; Hu, Zhiqiang

    2013-01-01

    Bacterial biofilms are a growing concern in a broad range of areas. In this study, a mixture of RNA bacteriophages isolated from municipal wastewater was used to control and remove biofilms. At the concentrations of 400 and 4 × 10(7) PFU/mL, the phages inhibited Pseudomonas aeruginosa biofilm formation by 45 ± 15% and 73 ± 8%, respectively. At the concentrations of 6,000 and 6 × 10(7) PFU/mL, the phages removed 45 ± 9% and 75 ± 5% of pre-existing P. aeruginosa biofilms, respectively. Chlorine reduced biofilm growth by 86 ± 3% at the concentration of 210 mg/L, but it did not remove pre-existing biofilms. However, a combination of phages (3 × 10(7) PFU/mL) and chlorine at this concentration reduced biofilm growth by 94 ± 2% and removed 88 ± 6% of existing biofilms. In a continuous flow system with continued biofilm growth, a combination of phages (a one-time treatment at the concentration of 1.9 × 10(8) PFU/mL for 1 h first) with chlorine removed 97 ± 1% of biofilms after Day 5 while phage and chlorine treatment alone removed 89 ± 1% and 40 ± 5%, respectively. For existing biofilms, a combined use of a lower phage concentration (3.8 × 10(5) PFU/mL) and chlorination with a shorter time duration (12 h) followed by continuous water flushing removed 96 ± 1% of biofilms in less than 2 days. Laser scanning confocal microscopy supplemented with electron microscopy indicated that the combination treatment resulted in biofilms with lowest cell density and viability. These results suggest that the combination treatment of phages and chlorine is a promising method to control and remove bacterial biofilms from various surfaces.

  11. The Adaptation of Temperate Bacteriophages to Their Host Genomes

    PubMed Central

    Bobay, Louis-Marie; Rocha, Eduardo P.C.; Touchon, Marie

    2013-01-01

    Rapid turnover of mobile elements drives the plasticity of bacterial genomes. Integrated bacteriophages (prophages) encode host-adaptive traits and represent a sizable fraction of bacterial chromosomes. We hypothesized that natural selection shapes prophage integration patterns relative to the host genome organization. We tested this idea by detecting and studying 500 prophages of 69 strains of Escherichia and Salmonella. Phage integrases often target not only conserved genes but also intergenic positions, suggesting purifying selection for integration sites. Furthermore, most integration hotspots are conserved between the two host genera. Integration sites seem also selected at the large chromosomal scale, as they are nonrandomly organized in terms of the origin–terminus axis and the macrodomain structure. The genes of lambdoid prophages are systematically co-oriented with the bacterial replication fork and display the host high frequency of polarized FtsK-orienting polar sequences motifs required for chromosome segregation. matS motifs are strongly avoided by prophages suggesting counter selection of motifs disrupting macrodomains. These results show how natural selection for seamless integration of prophages in the chromosome shapes the evolution of the bacterium and the phage. First, integration sites are highly conserved for many millions of years favoring lysogeny over the lytic cycle for temperate phages. Second, the global distribution of prophages is intimately associated with the chromosome structure and the patterns of gene expression. Third, the phage endures selection for DNA motifs that pertain exclusively to the biology of the prophage in the bacterial chromosome. Understanding prophage genetic adaptation sheds new lights on the coexistence of horizontal transfer and organized bacterial genomes. PMID:23243039

  12. An Ensemble Method to Distinguish Bacteriophage Virion from Non-Virion Proteins Based on Protein Sequence Characteristics.

    PubMed

    Zhang, Lina; Zhang, Chengjin; Gao, Rui; Yang, Runtao

    2015-01-01

    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. An Ensemble Method to Distinguish Bacteriophage Virion from Non-Virion Proteins Based on Protein Sequence Characteristics

    PubMed Central

    Zhang, Lina; Zhang, Chengjin; Gao, Rui; Yang, Runtao

    2015-01-01

    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 scientists, a user-friendly and publicly-accessible web-server for the proposed ensemble method is established. PMID:26370987

  14. Complete Genome Sequence of Bacteriophage Deep-Blue Infecting Emetic Bacillus cereus.

    PubMed

    Hock, Louise; Gillis, Annika; Mahillon, Jacques

    2016-01-01

    The Bacillus cereus emetic pathotype is responsible for important food-borne intoxications. Here, we describe the complete genome sequence of bacteriophage Deep-Blue, which is able to infect emetic strains of B. cereus Deep-Blue is a 159-kb myophage of the Bastille-like group within the Spounavirinae.

  15. Complete Genome Sequence of Bacillus cereus Sensu Lato Bacteriophage Bcp1.

    PubMed

    Schuch, Raymond; Pelzek, Adam J; Fazzini, Monica M; Nelson, Daniel C; Fischetti, Vincent A

    2014-01-01

    Bacillus cereus sensu lato organisms are an ecologically diverse group that includes etiologic agents of food poisoning, periodontal disease, and anthrax. The recently identified Bcp1 bacteriophage infects B. cereus sensu lato and is being developed as a therapeutic decontamination agent and diagnostic countermeasure. We announce the complete genome sequence of Bcp1.

  16. Characterization of an unusual bipolar helicase encoded by bacteriophage T5.

    PubMed

    Wong, Io Nam; Sayers, Jon R; Sanders, Cyril M

    2013-04-01

    Bacteriophage T5 has a 120 kb double-stranded linear DNA genome encoding most of the genes required for its own replication. This lytic bacteriophage has a burst size of ∼500 new phage particles per infected cell, demonstrating that it is able to turn each infected bacterium into a highly efficient DNA manufacturing machine. To begin to understand DNA replication in this prodigious bacteriophage, we have characterized a putative helicase encoded by gene D2. We show that bacteriophage T5 D2 protein is the first viral helicase to be described with bipolar DNA unwinding activities that require the same core catalytic residues for unwinding in either direction. However, unwinding of partially single- and double-stranded DNA test substrates in the 3'-5' direction is more robust and can be distinguished from the 5'-3' activity by a number of features including helicase complex stability, salt sensitivity and the length of single-stranded DNA overhang required for initiation of helicase action. The presence of D2 in an early gene cluster, the identification of a putative helix-turn-helix DNA-binding motif outside the helicase core and homology with known eukaryotic and prokaryotic replication initiators suggest an involvement for this unusual helicase in DNA replication initiation.

  17. Resolving the database sequence discrepancies for the Staphylococcus aureus bacteriophage phi 11 amidase.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are two conflicting primary nucleotide sequences of the Staphylococcus aureus bacteriophage '11 amidase gene in public databases. Nucleotide sequence differences as well as alternative translational start site assignments result in three non-identical protein sequence predictions in Genbank f...

  18. Complete genome sequence of T4-Like Escherichia coli bacteriophage HX01.

    PubMed

    Tang, Fang; Li, Yanzhe; Zhang, Wei; Lu, Chengping

    2012-12-01

    Phage T4 is among the best-characterized biological systems (S. Kanamaru and F. Arisaka, Seikagaku 74:131-135, 2002; E. S. Miller et al., Microbiol. Mol. Biol. Rev. 67:86-156, 2003; W. B. Wood and H. R. Revel, Bacteriol. Rev. 40:847-868, 1976). To date, several genomes of T4-like bacteriophages are available in public databases but without any APEC bacteriophages (H. Jiang et al., Arch. Virol. 156:1489-1492, 2011; L. Kaliniene, V. Klausa, A. Zajanckauskaite, R. Nivinskas, and L. Truncaite, Arch. Virol. 156:1913-1916, 2011; J. H. Kim et al., Vet. Microbiol. 157:164-171, 2012; W. C. Liao et al., J. Virol. 85:6567-6578, 2011). We isolated a bacteriophage from a duck factory, named HX01, that infects avian pathogenic Escherichia coli (APEC). Sequence and morphological analyses revealed that phage HX01 is a T4-like bacteriophage and belongs to the family Myoviridae. Here, we announce the complete genome sequence of phage HX01 and report the results of our analysis. PMID:23166268

  19. Genome Sequence of the Enterohemorrhagic Escherichia coli Bacteriophage UFV-AREG1

    PubMed Central

    Batalha, Laís Silva; Albino, Luiz Augusto A.; Boggione, Delaine Meireles Gouveia; Gontijo, Marco Tulio Pardini; Bazzolli, Denise M. Soares; Mendonca, Regina C. Santos

    2016-01-01

    Here, we present the genome sequence of the Escherichia coli bacteriophage UFV-AREG1. This phage was isolated from cowshed wastewater and showed specificity for enterohemorrhagic E. coli O157:H7 (ATCC 43895), E. coli 0111 (CDC O11ab) and E. coli (ATCC 23229). PMID:27738021

  20. Problem-Solving Test: RNA and Protein Synthesis in Bacteriophage-Infected "E. coli" Cells

    ERIC Educational Resources Information Center

    Szeberenyi, Jozsef

    2008-01-01

    The classic experiment presented in this problem-solving test was designed to identify the template molecules of translation by analyzing the synthesis of phage proteins in "Escherichia coli" cells infected with bacteriophage T4. The work described in this test led to one of the most seminal discoveries of early molecular biology: it dealt a…

  1. Interaction of Pseudomonas putida ATCC 12633 and Bacteriophage gh-1 in Berea Sandstone Rock

    PubMed Central

    Chang, Philip Lee; Yen, Teh Fu

    1985-01-01

    Measurements of the passage of Pseudomonas putida ATCC 12633 and a phage-resistant mutant through Berea sandstone rock were made. When bacteriophage gh-1 was adsorbed within the rock matrix, a reduction in the passage of the susceptible but not the resistant cells through the rock was observed. PMID:16346956

  2. Interaction of Pseudomonas putida ATCC 12633 and Bacteriophage gh-1 in Berea Sandstone Rock.

    PubMed

    Chang, P L; Yen, T F

    1985-12-01

    Measurements of the passage of Pseudomonas putida ATCC 12633 and a phage-resistant mutant through Berea sandstone rock were made. When bacteriophage gh-1 was adsorbed within the rock matrix, a reduction in the passage of the susceptible but not the resistant cells through the rock was observed.

  3. 76 FR 66187 - Bacteriophage of Clavibacter Michiganensis Subspecies Michiganensis; Exemption From the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-26

    ... Findings In the Federal Register of September 23, 2009 (74 FR 48556) (FRL- 8434-7), EPA issued a notice... December 28, 2005 (70 FR 76704) (FRL-7753-6)). Much like the previously registered bacteriophage, Omni... from review under Executive Order 12866, entitled Regulatory Planning and Review (58 FR 51735,...

  4. Isolation and Genetic Analysis of an Environmental Bacteriophage: A 10-Session Laboratory Series in Molecular Virology

    ERIC Educational Resources Information Center

    Williamson, Ryan P.; Barker, Brent T.; Drammeh, Hamidou; Scott, Jefferson; Lin, Joseph

    2014-01-01

    Bacterial viruses, otherwise known as bacteriophage (or phage), are some of the most abundant viruses found in the environment. They can be easily isolated from water or soil and are ideal for use in laboratory classrooms due to their ease of culture and inherent safety. Here, we describe a series of 10 laboratory exercises where students collect,…

  5. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN...

  6. Bacteriophages and their applications in the diagnosis and treatment of hepatitis B virus infection

    PubMed Central

    Bakhshinejad, Babak; Sadeghizadeh, Majid

    2014-01-01

    Hepatitis B virus (HBV) infection is a major global health challenge leading to serious disorders such as cirrhosis and hepatocellular carcinoma. Currently, there exist various diagnostic and therapeutic approaches for HBV infection. However, prevalence and hazardous effects of chronic viral infection heighten the need to develop novel methodologies for the detection and treatment of this infection. Bacteriophages, viruses that specifically infect bacterial cells, with a long-established tradition in molecular biology and biotechnology have recently been introduced as novel tools for the prevention, diagnosis and treatment of HBV infection. Bacteriophages, due to tremendous genetic flexibility, represent potential to undergo a huge variety of surface modifications. This property has been the rationale behind introduction of phage display concept. This powerful approach, together with combinatorial chemistry, has shaped the concept of phage display libraries with diverse applications for the detection and therapy of HBV infection. This review aims to offer an insightful overview of the potential of bacteriophages in the development of helpful prophylactic (vaccine design), diagnostic and therapeutic strategies for HBV infection thereby providing new perspectives to the growing field of bacteriophage researches directing towards HBV infection. PMID:25206272

  7. Bacteriophage remediation of bacterial pathogens in aquaculture: a review of the technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  8. Complete genome sequence of the podoviral bacteriophage CP24R virulent for Clostridium perfringens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacteriophage 'CP24R was isolated from raw sewage of a waste treatment plant and lytic activity was observed against a type C Clostridium perfringens isolate. Electron microscopy revealed a small virion (44nm diameter icosahedral capsid) with a short, non-contractile tail, indicative of the family ...

  9. Creating highly amplified enzyme-linked immunosorbent assay signals from genetically engineered bacteriophage.

    PubMed

    Brasino, Michael; Lee, Ju Hun; Cha, Jennifer N

    2015-02-01

    For early detection of many diseases, it is critical to be able to diagnose small amounts of biomarkers in blood or serum. One of the most widely used sensing assays is the enzyme-linked immunosorbent assay (ELISA), which typically uses detection monoclonal antibodies conjugated to enzymes to produce colorimetric signals. To increase the overall sensitivities of these sensors, we demonstrate the use of a dually modified version of filamentous bacteriophage Fd that produces significantly higher colorimetric signals in ELISAs than what can be achieved using antibodies alone. Because only a few proteins at the tip of the micron-long bacteriophage are involved in antigen binding, the approximately 4000 other coat proteins can be augmented-by either chemical functionalization or genetic engineering-with hundreds to thousands of functional groups. In this article, we demonstrate the use of bacteriophage that bear a large genomic fusion that allows them to bind specific antibodies on coat protein 3 (p3) and multiple biotin groups on coat protein 8 (p8) to bind to avidin-conjugated enzymes. In direct ELISAs, the anti-rTNFα (recombinant human tumor necrosis factor alpha)-conjugated bacteriophage show approximately 3- to 4-fold gains in signal over that of anti-rTNFα, demonstrating their use as a platform for highly sensitive protein detection.

  10. Complete Genome Sequence of Arthrobacter sp. ATCC 21022, a Host for Bacteriophage Discovery

    PubMed Central

    Russell, Daniel A.

    2016-01-01

    We report the complete genome sequence of Arthrobacter sp. ATCC 21022, a strain maintained by ATCC and a commonly used host for bacteriophage isolation and genomic analysis. The strain is prophage-free and CRISPR-free but codes for two predicted restriction-modification systems. PMID:27013048

  11. Assembly of a bacteriophage-based template for the organization of materials into nanoporous networks

    PubMed Central

    Courchesne, Noémie-Manuelle Dorval; Klug, Matthew T.; Chen, Po-Yen; Kooi, Steven E.; Yun, Dong Soo; Hong, Nina; Fang, Nicholas X.

    2014-01-01

    M13 bacteriophages are assembled via a covalent layer-by-layer process to form a highly nanoporous network capable of organizing nanoparticles and acting as a scaffold for templating metal-oxides. The morphological and optical properties of the film itself are presented as well as its ability to organize and disperse metal nanoparticles. PMID:24648015

  12. Bacteriophages and their applications in the diagnosis and treatment of hepatitis B virus infection.

    PubMed

    Bakhshinejad, Babak; Sadeghizadeh, Majid

    2014-09-01

    Hepatitis B virus (HBV) infection is a major global health challenge leading to serious disorders such as cirrhosis and hepatocellular carcinoma. Currently, there exist various diagnostic and therapeutic approaches for HBV infection. However, prevalence and hazardous effects of chronic viral infection heighten the need to develop novel methodologies for the detection and treatment of this infection. Bacteriophages, viruses that specifically infect bacterial cells, with a long-established tradition in molecular biology and biotechnology have recently been introduced as novel tools for the prevention, diagnosis and treatment of HBV infection. Bacteriophages, due to tremendous genetic flexibility, represent potential to undergo a huge variety of surface modifications. This property has been the rationale behind introduction of phage display concept. This powerful approach, together with combinatorial chemistry, has shaped the concept of phage display libraries with diverse applications for the detection and therapy of HBV infection. This review aims to offer an insightful overview of the potential of bacteriophages in the development of helpful prophylactic (vaccine design), diagnostic and therapeutic strategies for HBV infection thereby providing new perspectives to the growing field of bacteriophage researches directing towards HBV infection.

  13. Removal of endotoxins from bacteriophage preparations by extraction with organic solvents.

    PubMed

    Szermer-Olearnik, Bożena; Boratyński, Janusz

    2015-01-01

    Lipopolysaccharide (LPS, endotoxin, pyrogen) constitutes a very troubling contaminant of crude phage lysates produced in Gram-negative bacteria. Toxicity of LPS depends on the strong innate immunity response including the cytokines. Therefore, its removal is important for bacteriophage applications. In this paper, we present a procedure for extractive removal of endotoxin from bacteriophage preparations with water immiscible solvents (1-octanol or 1-butanol). During extraction most of the phage lytic activity is retained in the aqueous phase, while endotoxin accumulates in the organic solvent. The levels of endotoxin (expressed as endotoxin units, EU) in the aqueous bacteriophage-containing fraction determined by limulus amebocyte lysate or EndoLISA assay were exceptionally low. While the initial endotoxin levels in the crude phage lysates ranged between 10(3) and 10(5) EU/ml the average level after organic extraction remaining in the aqueous fraction was 5.3 EU/ml. These values when related to phage titers decreased from 10(3)-10(5) EU/10(9) PFU (plaque forming units) down to an average of 2.8 EU/10(9) PFU. The purification procedure is scalable, efficient and applicable to all the bacteriophages tested: T4, HAP1 (E. coli) and F8 (P. aeruginosa).

  14. Evaluation of consumers’ perception and willingness to pay for bacteriophage treated fresh produce

    PubMed Central

    Naanwaab, Cephas; Yeboah, Osei-Agyeman; Ofori Kyei, Foster; Sulakvelidze, Alexander; Goktepe, Ipek

    2014-01-01

    Food-borne illnesses caused by bacteria such as enterohemorrhagic E. coli and Salmonella spp. take a significant toll on American consumers’ health; they also cost the United States an estimated $77.7 billion annually in health care and other losses.1 One novel modality for improving the safety of foods is application of lytic bacteriophages directly onto foods, in order to reduce or eliminate their contamination with specific foodborne bacterial pathogens. The main objective of this study was to assess consumers’ perception about foods treated with bacteriophages and examine their willingness to pay (WTP) an additional amount (10–30 cents/lb) for bacteriophage-treated fresh produce. The study utilized a survey questionnaire administered by telephone to consumers in 4 different states: Alabama, Georgia, North Carolina, and South Carolina. The results show that consumers are in general willing to pay extra for bacteriophage-treated fresh produce if it improves their food safety. However, income, race, and the state where a consumer lives are significant determinants in their WTP. PMID:26713224

  15. Bacteriophage-encoded cochaperonins can substitute for Escherichia coli’s essential GroES protein

    PubMed Central

    Keppel, France; Rychner, Monique; Georgopoulos, Costa

    2002-01-01

    The Escherichia coli chaperonin machine is composed of two members, GroEL and GroES. The GroEL chaperonin can bind 10–15% of E. coli’s unfolded proteins in one of its central cavities and help them fold in cooperation with the GroES cochaperonin. Both proteins are absolutely essential for bacterial growth. Several large, lytic bacteriophages, such as T4 and RB49, use the host-encoded GroEL in conjunction with their own bacteriophage-encoded cochaperonin for the correct assembly of their major capsid protein, suggesting a cochaperonin specificity for the in vivo folding of certain substrates. Here, we demonstrate that, when the cochaperonin of either bacteriophage T4 (Gp31) or RB49 (CocO) is expressed in E. coli, the otherwise essential groES gene can be deleted. Thus, it appears that, despite very little sequence identity with groES, the bacteriophage-encoded Gp31 and CocO proteins are capable of replacing GroES in the folding of E. coli’s essential, housekeeping proteins. PMID:12189177

  16. Molecular Characterization of Podoviridae Bacteriophages Virulent for Clostridium perfringens and Comparison of Their Predicted Lytic Proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Clostridium perfringens is a Gram-positive, spore-forming anaerobic bacterium that plays a significant role in human food-borne disease as well as non-food-borne human, animal and poultry diseases. There has been a resurgent interest in the use of bacteriophages or their gene products to control ba...

  17. Evolutionarily distinct bacteriophage endolysins featuring conserved peptidoglycan cleavage sites protect mice from MRSA infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Staphylococcus aureus is a Gram-positive pathogen relevant for both human and animal health. With multi-drug resistant S. aureus strains becoming increasingly prevalent, alternative therapeutics are urgently needed. Bacteriophage endolysins (peptidoglycan hydrolases, PGH) are capable of killing Gra...

  18. In vitro evaluation of a novel bacteriophage cocktail as a preventative for bovine coliform mastitis.

    PubMed

    Porter, J; Anderson, J; Carter, L; Donjacour, E; Paros, M

    2016-03-01

    The objective of this study was to investigate the potential use of bacteriophage in preventing Escherichia coli mastitis on dairies. A cocktail consisting of 4 distinct bacteriophages was generated by screening against 36 E. coli isolates from dairy cows in Washington State with clinical mastitis. The bacteriophage significantly inhibited growth of 58% of the Washington State isolates and 54% of E. coli mastitis isolates from New York State, suggesting that the cocktail of phages had a relatively broad spectrum of action against relevant strains from 2 distinct geographies. The ability to suppress bacterial growth of these isolates in a liquid growth medium was not affected by the ratio of bacteriophage particles to bacterial cells (multiplicity of infection, MOI). For those E. coli that were completely inhibited by the phage cocktail, an MOI as low as 10 had the same effect as 10 µg/mL of ceftiofur on the growth rate of E. coli over a 12-h period using optical density measurements. A 3.3- to 5.6-log reduction of growth was achieved when E. coli was co-incubated with our phage cocktail in raw milk over a 12-h period at physiologic temperature. A modified gentamicin protection assay using bovine mammary epithelial cells provided a model to test whether bacteriophage could prevent cell attachment and invasion by chronic coliform mastitis strains. Pretreatment of cell cultures with the phage cocktail significantly reduced adhesion and intracellular survival of E. coli compared with controls. When combined with a bismuth-based teat sealant, the phage cocktail was able to inhibit bacterial growth when challenged with 1.6 × 10(3) cfu/mL of a clinical mastitis E. coli strain. In vitro results show bactericidal activity by our phage in raw milk and mammary tissue culture systems. Before a bacteriophage-based dry-cow treatment becomes a potential option for dairies, in vivo studies must be able to demonstrate that a specific dose of bacteriophage can protect cows from

  19. In vitro evaluation of a novel bacteriophage cocktail as a preventative for bovine coliform mastitis.

    PubMed

    Porter, J; Anderson, J; Carter, L; Donjacour, E; Paros, M

    2016-03-01

    The objective of this study was to investigate the potential use of bacteriophage in preventing Escherichia coli mastitis on dairies. A cocktail consisting of 4 distinct bacteriophages was generated by screening against 36 E. coli isolates from dairy cows in Washington State with clinical mastitis. The bacteriophage significantly inhibited growth of 58% of the Washington State isolates and 54% of E. coli mastitis isolates from New York State, suggesting that the cocktail of phages had a relatively broad spectrum of action against relevant strains from 2 distinct geographies. The ability to suppress bacterial growth of these isolates in a liquid growth medium was not affected by the ratio of bacteriophage particles to bacterial cells (multiplicity of infection, MOI). For those E. coli that were completely inhibited by the phage cocktail, an MOI as low as 10 had the same effect as 10 µg/mL of ceftiofur on the growth rate of E. coli over a 12-h period using optical density measurements. A 3.3- to 5.6-log reduction of growth was achieved when E. coli was co-incubated with our phage cocktail in raw milk over a 12-h period at physiologic temperature. A modified gentamicin protection assay using bovine mammary epithelial cells provided a model to test whether bacteriophage could prevent cell attachment and invasion by chronic coliform mastitis strains. Pretreatment of cell cultures with the phage cocktail significantly reduced adhesion and intracellular survival of E. coli compared with controls. When combined with a bismuth-based teat sealant, the phage cocktail was able to inhibit bacterial growth when challenged with 1.6 × 10(3) cfu/mL of a clinical mastitis E. coli strain. In vitro results show bactericidal activity by our phage in raw milk and mammary tissue culture systems. Before a bacteriophage-based dry-cow treatment becomes a potential option for dairies, in vivo studies must be able to demonstrate that a specific dose of bacteriophage can protect cows from

  20. STUDIES ON THE BACTERIOPHAGE OF D'HERELLE : VIII. THE MECHANISM OF LYSIS OF DEAD BACTERIA IN THE PRESENCE OF BACTERIOPHAGE.

    PubMed

    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

  1. Bacteriophage-Resistant Mutants in Yersinia pestis: Identification of Phage Receptors and Attenuation for Mice

    PubMed Central

    Filippov, Andrey A.; Sergueev, Kirill V.; He, Yunxiu; Huang, Xiao-Zhe; Gnade, Bryan T.; Mueller, Allen J.; Fernandez-Prada, Carmen M.; Nikolich, Mikeljon P.

    2011-01-01

    Background Bacteriophages specific for Yersinia pestis are routinely used for plague diagnostics and could be an alternative to antibiotics in case of drug-resistant plague. A major concern of bacteriophage therapy is the emergence of phage-resistant mutants. The use of phage cocktails can overcome this problem but only if the phages exploit different receptors. Some phage-resistant mutants lose virulence and therefore should not complicate bacteriophage therapy. Methodology/Principal Findings The purpose of this work was to identify Y. pestis phage receptors using site-directed mutagenesis and trans-complementation and to determine potential attenuation of phage-resistant mutants for mice. Six receptors for eight phages were found in different parts of the lipopolysaccharide (LPS) inner and outer core. The receptor for R phage was localized beyond the LPS core. Most spontaneous and defined phage-resistant mutants of Y. pestis were attenuated, showing increase in LD50 and time to death. The loss of different LPS core biosynthesis enzymes resulted in the reduction of Y. pestis virulence and there was a correlation between the degree of core truncation and the impact on virulence. The yrbH and waaA mutants completely lost their virulence. Conclusions/Significance We identified Y. pestis receptors for eight bacteriophages. Nine phages together use at least seven different Y. pestis receptors that makes some of them promising for formulation of plague therapeutic cocktails. Most phage-resistant Y. pestis mutants become attenuated and thus should not pose a serious problem for bacteriophage therapy of plague. LPS is a critical virulence factor of Y. pestis. PMID:21980477

  2. Isolation, characterization and therapeutic potential assessment of bacteriophages virulent to Staphylococcus aureus associated with goat mastitis

    PubMed Central

    Mishra, A. K.; Sharma, N; Kumar, A; Kumar, N; Gundallahalli Bayyappa, M. R; Kumar, S; Kumar, N

    2014-01-01

    In the present study, the therapeutic potential of bacteriophages virulent to Staphylococcus aureus associated with goat mastitis were isolated, identified and assessed. Staphylococcus aureus (host or indicator bacterium) was isolated from a goat suffering from clinical mastitis. Based on cultural, morphological, biochemical tests and amplification of S. aureus specific thermonuclease gene in PCR, the identity of the organism was confirmed as S. aureus. Bacteriophages were isolated from soil and faecal samples (n=42) collected from different parts of the Mathura district in Uttar Pradesh (India), and their identity was confirmed by amplification of the bacteriophage-specific endolysin gene fragment in PCR. The thermal tolerance study revealed that all phage isolates were stable at 30 and 40°C with 100% lytic efficacy and their activities reduced to 62-80% at 50°C declining sharply at 60°C with less than 5% efficacy. Likewise, at pH = 6.5 and 7.5, the survivability of all isolates was 100% which reduced to 70-79% and 84-91% at pH = 5.5 and 8.5, respectively. All isolates were stable up to 3 months at 37°C, and for 16 months at 4°C but the stability of their respective endolysins only lasted for 12-23 days at 37°C and 6 months at 4°C. Three of the bacteriophage isolates, S. aureus phage/CIRG/1, S. aureus phage/CIRG/4 and S. aureus phage/CIRG/5 exhibited lytic activity against over 80% of the staphylococcal isolates. The results of the present study provide insight for the use of lytic bacteriophages for therapeutic interventions against multi-drug-resistant S. aureus inducing mastitis in goats. PMID:27175124

  3. Performance of viruses and bacteriophages for fecal source determination in a multi-laboratory, comparative study.

    PubMed

    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.

  4. Photoreactivation of bacteriophages after UV disinfection: role of genome structure and impacts of UV source.

    PubMed

    Rodriguez, Roberto A; Bounty, Sarah; Beck, Sara; Chan, Connie; McGuire, Christian; Linden, Karl G

    2014-05-15

    The UV inactivation kinetics of bacteriophages MS2, PhiX174, T1 and PRD1 and the potential of bacterial UV repair mechanisms to reactivate these bacteriophages is described here. The selected bacteriophages represent a range of genome size, single and double stranded genomes, circular and linear organization and RNA and DNA. Bacteriophages were exposed to UV irradiation from two different collimated beam UV irradiation sources (medium-pressure (MP) mercury lamps and low-pressure (LP) mercury lamps) and assayed during which host-phage cultures were exposed to photoreactivating light for 6 h, then incubated overnight at 37 °C in the dark. Dark controls following UV exposure were performed in parallel. UV inactivation kinetics (using dark controls) showed that circular ssDNA phage (PhiX174) was the most sensitive and linear ssRNA phage (MS2) was the more resistant phage. No photoreactivation was observed for MS2 (RNA phage) and the highest photoreactivation was observed for PRD1. In the case of PRD1, the dose required for 4-log reduction (dark control) was around 35 mJ/cm(2), with a similar dose observed for both UV sources (MP and LP). When the photoreactivation step was added, the dose required for 4-log reduction using LP lamps was 103 mJ/cm(2) and for MP lamps was 60 mJ/cm(2). Genome organization differences between bacteriophages play an important role in resistance to UV inactivation and potential photoreactivation mediated by bacterial host mechanisms. The use of photoreactivation during the assay of PRD1 creates a more conservative surrogate for potential use in UV challenge testing.

  5. The bacteriophage ϕ29 tail possesses a pore-forming loop for cell membrane penetration.

    PubMed

    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

  6. Merged infrared catalogue

    NASA Technical Reports Server (NTRS)

    Schmitz, M.; Brown, L. W.; Mead, J. M.; Nagy, T. A.

    1978-01-01

    A compilation of equatorial coordinates, spectral types, magnitudes, and fluxes from five catalogues of infrared observations is presented. This first edition of the Merged Infrared Catalogue contains 11,201 oservations from the Two-Micron Sky Survey, Observations of Infrared Radiation from Cool Stars, the Air Force Geophysics Laboratory four Color Infrared Sky Survey and its Supplemental Catalog, and from Catalog of 10 micron Celestial Objects (HALL). This compilation is a by-product of a computerized infrared data base under development at Goddard Space Flight Center; the objective is to maintain a complete and current record of all infrared observations from 1 micron m to 1000 micron m of nonsolar system objects. These observations are being placed into a standardized system.

  7. Infrared in automotive applications

    NASA Astrophysics Data System (ADS)

    Predmesky, Ronald L.; Zaluzec, Matthew J.

    1997-04-01

    As the automotive industry continues to develop advanced materials and manufacturing processes, infrared imaging has the potential to become a major tool in process monitoring and closed loop process control. This paper reviews five novel applications of infrared imaging in applications such as product testing, component manufacture, and vehicle assembly. Infrared was found to be effective as a diagnostics tool for characterizing disc brake systems and electronic engine control sensors. The effectiveness of infrared to qualify fuel nozzle backspray was used to optimize hardware design for fuel systems. Finally, infrared was found to be useful in vehicle assembly operations in the installation of windshield glass and instrument panel hardware where visual inspection was impractical. The speed of image capture and the availability of image processing software for real time image processing and closed loop process control will no doubt find more applications as infrared imaging finds its niche in the automotive industry.

  8. Single molecule studies of DNA packaging by bacteriophages

    NASA Astrophysics Data System (ADS)

    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

  9. The production of generalized transducing phage by bacteriophage lambda.

    PubMed

    Sternberg, N

    1986-01-01

    Generalized transduction has for about 30 years been a major tool in the genetic manipulation of bacterial chromosomes. However, throughout that time little progress has been made in understanding how generalized transducing particles are produced. The experiments presented in this paper use phage lambda to assess some of the factors that affect that process. The results of those experiments indicate: the production of generalized transducing particles by bacteriophage lambda is inhibited by the phage lambda exonuclease (Exo). Also inhibited by lambda Exo is the production of lambda docR particles, a class of particles whose packaging is initiated in bacterial DNA and terminated at the normal phage packaging site, cos. In contrast, the production of lambda docL particles, a class of particles whose packaging is initiated at cos and terminated in bacterial DNA, is unaffected by lambda Exo; lambda-generalized transducing particles are not detected in induced lysis-defective (S-) lambda lysogens until about 60-90 min after prophage induction. Since wild-type lambda would normally lyse cells by 60 min, the production of lambda-generalized transducing particles depends on the phage being lysis-defective; if transducing lysates are prepared by phage infection then the frequency of generalized transduction for different bacterial markers varies over a 10-20-fold range. In contrast, if transducing lysates are prepared by the induction of a lambda lysogen containing an excision-defective prophage, then the variation in transduction frequency is much greater, and markers adjacent to, and on both sides of, the prophage are transduced with much higher frequencies than are other markers; if the prophage is replication-defective then the increased transduction of prophage-proximal markers is eliminated; measurements of total DNA in induced lysogens indicate that part of the increase in transduction frequency following prophage induction can be accounted for by an increase in the

  10. Optical and infrared masers

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Ongoing research progress in the following areas is described: (1) tunable infrared light sources and applications; (2) precision frequency and wavelength measurements in the infrared with applications to atomic clocks; (3) zero-degree pulse propagation in resonant medium; (4) observation of Dicke superradiance in optically pumped HF gas; (5) unidirectional laser amplifier with built-in isolator; and (6) progress in infrared metal-to-metal point contact tunneling diodes.

  11. Early infrared astronomy

    NASA Astrophysics Data System (ADS)

    Lequeux, James

    2009-07-01

    I present a short history of infrared astronomy, from the first scientific approaches of the ‘radiant heat’ in the seventeenth century to the 1970's, the time when space infrared astronomy was developing very rapidly. The beginning of millimeter and submillimeter astronomy is also covered. As the progress of infrared astronomy was strongly dependent on detectors, some details are given on their development.

  12. Infrared microscope inspection apparatus

    DOEpatents

    Forman, Steven E.; Caunt, James W.

    1985-02-26

    Apparatus and system for inspecting infrared transparents, such as an array of photovoltaic modules containing silicon solar cells, includes an infrared microscope, at least three sources of infrared light placed around and having their axes intersect the center of the object field and means for sending the reflected light through the microscope. The apparatus is adapted to be mounted on an X-Y translator positioned adjacent the object surface.

  13. Infrared microscope inspection apparatus

    DOEpatents

    Forman, S.E.; Caunt, J.W.

    1985-02-26

    Apparatus and system for inspecting infrared transparents, such as an array of photovoltaic modules containing silicon solar cells, includes an infrared microscope, at least three sources of infrared light placed around and having their axes intersect the center of the object field and means for sending the reflected light through the microscope. The apparatus is adapted to be mounted on an X-Y translator positioned adjacent the object surface. 4 figs.

  14. IMPORTANCE OF THE DYNAMICS OF BACTERIOPHAGE-HOST INTERACTIONS TO BACTERIAL ABUNDANCE AND GENETIC DIVERSITY IN AQUATIC ENVIRONMENTS (RESEARCH BRIEF)

    EPA Science Inventory

    Using Pseudomonas aeruginosa and its bacteriophages as a model system, we have clearly demonstrated a significant potential for viral-mediated gene transfer (transduction) of both plasmid and chromosomal DNA in freshwater microbial populations. These investigations have predicted...

  15. Droplet optofluidic imaging for λ-bacteriophage detection via co-culture with host cell Escherichia coli.

    PubMed

    Yu, J Q; Huang, W; Chin, L K; Lei, L; Lin, Z P; Ser, W; Chen, H; Ayi, T C; Yap, P H; Chen, C H; Liu, A Q

    2014-09-21

    Bacteriophages are considered as attractive indicators for determining drinking water quality since its concentration is strongly correlated with virus concentrations in water samples. Previously, bacteriophage detection was based on a plague assay that required a complicated labelling technique and a time-consuming culture assay. Here, for the first time, a label-free bacteriophage detection is reported by using droplet optofluidic imaging, which uses host-cell-containing microdroplets as reaction carriers for bacteriophage infection due to a higher contact ratio. The optofluidic imaging is based on the effective refractive index changes in the microdroplet correlated with the growth rate of the infected host cells, which is highly sensitive, i.e. can detect one E. coli cell. The droplet optofluidic system is not only used in drinking water quality monitoring, but also has high potential applications for pathogenic bacteria detection in clinical diagnosis and food industry.

  16. Characterization of FP22, a large streptomycete bacteriophage with DNA insensitive to cleavage by many restriction enzymes.

    PubMed

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

    1990-12-01

    Bacteriophage FP22 has a very broad host range within streptomycetes and appeared to form lysogens of Streptomyces ambofaciens ATCC 15154. FP22 shared strong cross-immunity and antibody cross-reactivity with bacteriophage P23, but not with seven other streptomycete bacteriophages. FP22 particles had a head diameter of 71 nm and a tail length of 307 nm. The FP22 genome was 131 kb, which is the largest bacteriophage genome reported for streptomycetes. The G + C content of the genome was 46 mol% and restriction mapping indicated that FP22 DNA had discrete ends. NaCl- and pyrophosphate-resistant deletion mutants were readily isolated and the extent of the deletions defined at least 23 kb of dispensable DNA in two regions of the genome. The DNA was not cleaved by most restriction endonucleases (or isoschizomers) which have been identified in the streptomycetes, including the tetranucleotide cutter MboI (GATC).

  17. Comparative genomics of four closely related Clostridium perfringens bacteriophages reveals variable rates of evolution within a core genome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Biotechnological uses of bacteriophage gene products as alternatives to conventional antibiotics will require a thorough understanding of their genomic context. We sequenced and analyzed the genomes of four closely related phages isolated from Clostridium perfringens, an important agricu...

  18. STUDIES ON THE BACTERIOPHAGE OF D'HERELLE : IX. EVIDENCE OF HYDROLYSIS OF BACTERIAL PROTEIN DURING LYSIS.

    PubMed

    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.

  19. Far infrared supplement: Catalog of infrared observations, second edition

    NASA Technical Reports Server (NTRS)

    Gezari, Daniel Y.; Schmitz, Marion; Mead, Jaylee M.

    1988-01-01

    The Far Infrared Supplement: Catalog of Infrared Observations summarizes all infrared astronomical observations at far infrared wavelengths (5 to 1000 microns) published in the scientific literature from 1965 through 1986. The Supplement list contain 25 percent of the observations in the full Catalog of Infrared Observations (CIO), and essentially eliminates most visible stars from the listings. The Supplement is thus more compact than the main catalog, and is intended for easy reference during astronomical observations. The Far Infrared Supplement (2nd Edition) includes the Index of Infrared Source Positions and the Bibliography of Infrared Astronomy for the subset of far infrared observations listed.

  20. Far infrared supplement: Catalog of infrared observations, second edition

    NASA Astrophysics Data System (ADS)

    Gezari, Daniel Y.; Schmitz, Marion; Mead, Jaylee M.

    1988-08-01

    The Far Infrared Supplement: Catalog of Infrared Observations summarizes all infrared astronomical observations at far infrared wavelengths (5 to 1000 microns) published in the scientific literature from 1965 through 1986. The Supplement list contain 25 percent of the observations in the full Catalog of Infrared Observations (CIO), and essentially eliminates most visible stars from the listings. The Supplement is thus more compact than the main catalog, and is intended for easy reference during astronomical observations. The Far Infrared Supplement (2nd Edition) includes the Index of Infrared Source Positions and the Bibliography of Infrared Astronomy for the subset of far infrared observations listed.