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Sample records for well-defined bacteriophage cocktail

  1. Quality-controlled small-scale production of a well-defined bacteriophage cocktail for use in human clinical trials.

    Directory of Open Access Journals (Sweden)

    Maya Merabishvili

    Full Text Available We describe the small-scale, laboratory-based, production and quality control of a cocktail, consisting of exclusively lytic bacteriophages, designed for the treatment of Pseudomonas aeruginosa and Staphylococcus aureus infections in burn wound patients. Based on successive selection rounds three bacteriophages were retained from an initial pool of 82 P. aeruginosa and 8 S. aureus bacteriophages, specific for prevalent P. aeruginosa and S. aureus strains in the Burn Centre of the Queen Astrid Military Hospital in Brussels, Belgium. This cocktail, consisting of P. aeruginosa phages 14/1 (Myoviridae and PNM (Podoviridae and S. aureus phage ISP (Myoviridae was produced and purified of endotoxin. Quality control included Stability (shelf life, determination of pyrogenicity, sterility and cytotoxicity, confirmation of the absence of temperate bacteriophages and transmission electron microscopy-based confirmation of the presence of the expected virion morphologic particles as well as of their specific interaction with the target bacteria. Bacteriophage genome and proteome analysis confirmed the lytic nature of the bacteriophages, the absence of toxin-coding genes and showed that the selected phages 14/1, PNM and ISP are close relatives of respectively F8, phiKMV and phage G1. The bacteriophage cocktail is currently being evaluated in a pilot clinical study cleared by a leading Medical Ethical Committee.

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

    Science.gov (United States)

    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 food that tested positive for Salmonella. Our results indicate that bacteriophage biocontrol of S. enterica in dried pet food is technically feasible.

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

    Science.gov (United States)

    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

  4. Bacteriophage cocktail and multi-strain probiotics in the feed for weanling pigs: effects on intestine morphology and targeted intestinal coliforms and Clostridium.

    Science.gov (United States)

    Kim, J S; Hosseindoust, A; Lee, S H; Choi, Y H; Kim, M J; Lee, J H; Kwon, I K; Chae, B J

    2017-01-01

    Two experiments were conducted to investigate the effects of dietary supplementation of bacteriophage cocktail, probiotics and a combination of these two supplements on performance and gut health of weanling pigs. In Experiment 1, 150 weaned piglets were randomly allotted to three treatments on the basis of BW. The dietary treatments included a basal diet supplemented with 0 (control), 1.0 and 1.5 g/kg bacteriophage cocktail. Pigs fed 1.0 and 1.5 g/kg bacteriophage product had greater (Pprobiotic product (P), 1.0 g/kg bacteriophage cocktail (B) and combination of 1.0 g/kg bacteriophage cocktail and 3.0 g/kg fermented probiotic product. Pigs fed bacteriophage cocktail diets had greater (PProbiotics significantly increased G : F, colonization of Lactobacillus spp. in ileum. At day 35, bacteriophage treatment group showed greater (Pgut health of weanling pigs, however their combination with probiotics did not show an interaction.

  5. Bacteriophages with potential to inactivate Salmonella Typhimurium: Use of single phage suspensions and phage cocktails.

    Science.gov (United States)

    Pereira, Carla; Moreirinha, Catarina; Lewicka, Magdalena; Almeida, Paulo; Clemente, Carla; Cunha, Ângela; Delgadillo, Ivonne; Romalde, Jésus L; Nunes, Maria L; Almeida, Adelaide

    2016-07-15

    The aim of this study was to compare the dynamics of three previously isolated bacteriophages (or phages) individually (phSE-1, phSE-2 and phSE-5) or combined in cocktails of two or three phages (phSE-1/phSE-2, phSE-1/phSE-5, phSE-2/phSE-5 and phSE-1/phSE-2/phSE-5) to control Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) in order to evaluate their potential application during depuration. Phages were assigned to the family Siphoviridae and revealed identical restriction digest profiles, although they showed a different phage adsorption, host range, burst size, explosion time and survival in seawater. The three phages were effective against S. Typhimurium (reduction of ∼2.0 log CFU/mL after 4h treatment). The use of cocktails was not significantly more effective than the use of single phages. A big fraction of the remained bacteria are phage-resistant mutants (frequency of phage-resistant mutants 9.19×10(-5)-5.11×10(-4)) but phage- resistant bacterial mutants was lower for the cocktail phages than for the single phage suspensions and the phage phSE-1 presented the highest rate of resistance and phage phSE-5 the lowest one. The spectral changes of S. Typhimurium resistant and phage-sensitive cells were compared and revealed relevant differences for peaks associated to amide I (1620cm(-1)) and amide II (1515cm(-1)) from proteins and from carbohydrates and phosphates region (1080-1000cm(-1)). Despite the similar efficiency of individual phages, the development of lower resistance indicates that phage cocktails might be the most promising choice to be used during the bivalve depuration to control the transmission of salmonellosis.

  6. A cocktail of three virulent bacteriophages prevents Vibrio cholerae infection in animal models

    Science.gov (United States)

    Yen, Minmin; Cairns, Lynne S.; Camilli, Andrew

    2017-01-01

    Effective prevention strategies will be essential in reducing disease burden due to bacterial infections. Here we harness the specificity and rapid-acting properties of bacteriophages as a potential prophylaxis therapy for cholera, a severely dehydrating disease caused by Vibrio cholerae. To this end, we test a cocktail of three virulent phages in two animal models of cholera pathogenesis (infant mouse and rabbit models). Oral administration of the phages up to 24 h before V. cholerae challenge reduces colonization of the intestinal tract and prevents cholera-like diarrhea. None of the surviving V. cholerae colonies are resistant to all three phages. Genome sequencing and variant analysis of the surviving colonies indicate that resistance to the phages is largely conferred by mutations in genes required for the production of the phage receptors. For acute infections, such as cholera, phage prophylaxis could provide a strategy to limit the impact of bacterial disease on human health. PMID:28146150

  7. What Can We Learn from a Metagenomic Analysis of a Georgian Bacteriophage Cocktail?

    Directory of Open Access Journals (Sweden)

    Henrike Zschach

    2015-12-01

    Full Text Available Phage therapy, a practice widespread in Eastern Europe, has untapped potential in the combat against antibiotic-resistant bacterial infections. However, technology transfer to Western medicine is proving challenging. Bioinformatics analysis could help to facilitate this endeavor. In the present study, the Intesti phage cocktail, a key commercial product of the Eliava Institute, Georgia, has been tested on a selection of bacterial strains, sequenced as a metagenomic sample, de novo assembled and analyzed by bioinformatics methods. Furthermore, eight bacterial host strains were infected with the cocktail and the resulting lysates sequenced and compared to the unamplified cocktail. The analysis identified 23 major phage clusters in different abundances in the cocktail, among those clusters related to the ICTV genera T4likevirus, T5likevirus, T7likevirus, Chilikevirus and Twortlikevirus, as well as a cluster that was quite distant to the database sequences and a novel Proteus phage cluster. Examination of the depth of coverage showed the clusters to have different abundances within the cocktail. The cocktail was found to be composed primarily of Myoviridae (35% and Siphoviridae (32%, with Podoviridae being a minority (15%. No undesirable genes were found.

  8. [Susceptibilities of multidrug-resistant pathogens responsible for complicated skin and soft tissue infections to standard bacteriophage cocktails].

    Science.gov (United States)

    Gündoğdu, Aycan; Kılıç, Hüseyin; Ulu Kılıç, Ayşegül; Kutateladze, Mzia

    2016-04-01

    Skin and soft tissue infections (SSTIs) may represent a wide clinical spectrum from cellulitis to high-mortality associated necrotizing fasciitis. Limitations in therapy due to the multiple drug resistance, leads to increase in the morbidity and mortality rates, especially in complicated SSTIs such as diabetic foot, decubitus, and surgical wound infections. Therefore, alternative treatment strategies other than antibiotics are needed in appropriate clinical conditions. "Bacteriophage therapy", which is an old method and has been used as part of standard treatment in some countries such as Georgia and Russia, has again become popular worldwide. The aim of this study was to investigate the in vitro susceptibilities of multidrug-resistant (MDR) pathogens isolated from patients with complicated SSTIs, against standard bacteriophage (phage) cocktails. Six different ready-made phage preparations [Pyophage, Intestiphage, ENKO, SES, Fersisi and Staphylococcal Bacteriophage (Sb)] used in this study have been provided by G. Eliava Institute, Georgia. Because of the absence of ready-made phage preparations for Acinetobacter baumannii and Klebsiella pneumoniae, Φ1-Φ7 and ΦKL1- ΦKL3 phages were used provided from the same institute's phage library, respectively. Isolation and identification of the pathogens from abscess and wound samples of patients with SSTIs were performed by conventional methods and automatized VITEK(®)-2 (bioMerieux, ABD) system. Antimicrobial susceptibility testing was conducted complying CLSI standards' and the bacteria that were resistant to at least two different antibiotic groups were considered as MDR. Accordingly, a total of 33 isolates, nine of them were E.coli (8 ESBL and 1 ESBL + carbapenemase positive); nine were MDR P.aeruginosa; nine were MDR A.baumannii; three were methicillin-resistant Staphylococcus aureus (MRSA) and three were K.pneumoniae (1 ESBL, 1 carbapenemase and 1 ESBL + carbapenemase positive) were included in the study. The

  9. Effect of a bacteriophage cocktail in combination with modified atmosphere packaging in controlling Listeria monocytogenes on fresh-cut spinach

    Directory of Open Access Journals (Sweden)

    Boyacioglu O.

    2016-06-01

    Full Text Available A Listeria monocytogenes-specific bacteriophage cocktail was evaluated for its activity against a nalidixic acid-resistant L. monocytogenes (Lm-NalR isolate on fresh-cut spinach stored under modified atmosphere packaging at various temperatures. Pieces (~2 × 2 cm2 of fresh spinach inoculated with 4.5 log CFU/cm2 Lm-NalR were sprayed with the phage cocktail (6.5 log plaque-forming units [PFU]/cm2 or a control. The samples were stored at 4°C or 10°C for up to 14 d in sealed packages filled with either atmospheric air (AA or modified atmosphere (MA. At 4°C under AA, the phages significantly (P ≤ 0.05 lowered the Lm-NalR populations on spinach, compared to control-treated inoculated samples, by 1.12 and 1.51 log CFU/cm2 after 1 and 14 d, respectively. At 4°C under MA, Lm-NalR was significantly reduced by 1.95 log CFU/cm2 compared to control leaves after both 1 and 14 d. At 10°C under AA, the phages significantly reduced Lm-NalR by 1.50 and 2.51 log CFU/cm2 after 1 and 14 d compared to the control. Again at 10°C under MA, the phages significantly reduced Lm-NalR by 1.71 and 3.24 log CFU/cm2 compared to control after 1 and 14 d, respectively. The results support the potential of lytic bacteriophages in effectively reducing populations of L. monocytogenes on freshcut leafy produce, under both AA and MA conditions.

  10. Susceptibility of Escherichia coli isolated from uteri of postpartum dairy cows to antibiotic and environmental bacteriophages. Part II: In vitro antimicrobial activity evaluation of a bacteriophage cocktail and several antibiotics.

    Science.gov (United States)

    Santos, T M A; Gilbert, R O; Caixeta, L S; Machado, V S; Teixeira, L M; Bicalho, R C

    2010-01-01

    The use of pathogenic-specific antimicrobials, as proposed by bacteriophage therapy, is expected to reduce the incidence of resistance development. Eighty Escherichia coli isolated from uteri of Holstein dairy cows were phenotypically characterized for antimicrobial resistance to ampicillin, ceftiofur, chloramphenicol, florfenicol, spectinomycin, streptomycin, and tetracycline by broth microdilution method. The lytic activity of a bacteriophage cocktail against all isolates was performed by a similar method. Additionally, the effect of different concentrations of antimicrobials and multiplicities of infections (MOI) of the bacteriophage cocktail on E. coli growth curve was measured. Isolates exhibited resistance to ampicillin (33.7%), ceftiofur (1.2%), chloramphenicol (100%), and florfenicol (100%). All strains were resistant to at least 2 of the antimicrobial agents tested; multidrug resistance (>or=3 of 7 antimicrobials tested) was observed in 35% of E. coli isolates. The major multidrug resistance profile was found for ampicillin-chloramphenicol-florfenicol, which was observed in more than 96.4% of the multidrug-resistant isolates. The bacteriophage cocktail preparation showed strong antimicrobial activity against multidrug-resistant E. coli. Multiplicity of infection as low as 10(-4) affected the growth of the E. coli isolates. The ratio of 10 bacteriophage particles per bacterial cell (MOI=10(1)) was efficient in inhibiting at least 50% of all isolates. Higher MOI should be tested in future in vitro studies to establish ratios that completely inhibit bacterial growth during longer periods. All isolates resistant to florfenicol were resistant to chloramphenicol and, because florfenicol was recently introduced into veterinary clinics, this finding suggests that the selection pressure of chloramphenicol, as well as other antimicrobials, may still play a relevant role in the emergence and dissemination of florfenicol resistance in E. coli. The bacteriophage

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

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    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. © 2014 The Authors.

  12. Characterization of vB_SauM-fRuSau02, a Twort-Like Bacteriophage Isolated from a Therapeutic Phage Cocktail

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    Katarzyna Leskinen

    2017-09-01

    Full Text Available Staphylococcus aureus is a commensal and pathogenic bacterium that causes infections in humans and animals. It is a major cause of nosocomial infections worldwide. Due to increasing prevalence of multidrug resistance, alternative methods to eradicate the pathogen are necessary. In this respect, polyvalent staphylococcal myoviruses have been demonstrated to be excellent candidates for phage therapy. Here we present the characterization of the bacteriophage vB_SauM-fRuSau02 (fRuSau02 that was isolated from a commercial Staphylococcus bacteriophage cocktail produced by Microgen (Moscow, Russia. The genomic analysis revealed that fRuSau02 is very closely related to the phage MSA6, and possesses a large genome (148,464 bp, with typical modular organization and a low G+C (30.22% content. It can therefore be classified as a new virus among the genus Twortlikevirus. The genome contains 236 predicted genes, 4 of which were interrupted by insertion sequences. Altogether, 78 different structural and virion-associated proteins were identified from purified phage particles by liquid chromatography-tandem mass spectrometry (LC-MS/MS. The host range of fRuSau02 was tested with 135 strains, including 51 and 54 Staphylococcus aureus isolates from humans and pigs, respectively, and 30 coagulase-negative Staphylococcus strains of human origin. All clinical S. aureus strains were at least moderately sensitive to the phage, while only 39% of the pig strains were infected. Also, some strains of Staphylococcus intermedius, Staphylococcus lugdunensis, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus saprophyticus and Staphylococcus pseudointer were sensitive. We conclude that fRuSau02, a phage therapy agent in Russia, can serve as an alternative to antibiotic therapy against S. aureus.

  13. Development and Use of Personalized Bacteriophage-Based Therapeutic Cocktails To Treat a Patient with a Disseminated Resistant Acinetobacter baumannii Infection

    Science.gov (United States)

    Biswas, Biswajit; Gill, Jason J.; Hernandez-Morales, Adriana; Lancaster, Jacob; Lessor, Lauren; Barr, Jeremy J.; Reed, Sharon L.; Rohwer, Forest; Benler, Sean; Segall, Anca M.; Taplitz, Randy; Smith, Davey M.; Kerr, Kim; Kumaraswamy, Monika; Nizet, Victor; Lin, Leo; McCauley, Melanie D.; Strathdee, Steffanie A.; Benson, Constance A.; Pope, Robert K.; Leroux, Brian M.; Picel, Andrew C.; Mateczun, Alfred J.; Cilwa, Katherine E.; Regeimbal, James M.; Estrella, Luis A.; Wolfe, David M.; Henry, Matthew S.; Quinones, Javier; Salka, Scott; Bishop-Lilly, Kimberly A.; Young, Ry; Hamilton, Theron

    2017-01-01

    ABSTRACT Widespread antibiotic use in clinical medicine and the livestock industry has contributed to the global spread of multidrug-resistant (MDR) bacterial pathogens, including Acinetobacter baumannii. We report on a method used to produce a personalized bacteriophage-based therapeutic treatment for a 68-year-old diabetic patient with necrotizing pancreatitis complicated by an MDR A. baumannii infection. Despite multiple antibiotic courses and efforts at percutaneous drainage of a pancreatic pseudocyst, the patient deteriorated over a 4-month period. In the absence of effective antibiotics, two laboratories identified nine different bacteriophages with lytic activity for an A. baumannii isolate from the patient. Administration of these bacteriophages intravenously and percutaneously into the abscess cavities was associated with reversal of the patient's downward clinical trajectory, clearance of the A. baumannii infection, and a return to health. The outcome of this case suggests that the methods described here for the production of bacteriophage therapeutics could be applied to similar cases and that more concerted efforts to investigate the use of therapeutic bacteriophages for MDR bacterial infections are warranted. PMID:28807909

  14. Cleopatra's cocktail.

    Science.gov (United States)

    Jones, Prudence J

    2010-01-01

    Pliny the Elder's account of Cleopatra consuming a cocktail of vinegar and a pearl in order to win a bet with Antony was considered credible in the ancient world, but many modern scholars have relegated the anecdote to the realm of fantasy. This paper identifies possible reasons for this skepticism, including the visual tradition of the story and the belief that increasing concentration always increases reaction rate. Experiments reveal that, in the case of acetic acid and pearls, the concentration found in vinegar made from wine is ideal.

  15. Phage therapy pharmacology phage cocktails.

    Science.gov (United States)

    Chan, Benjamin K; Abedon, Stephen T

    2012-01-01

    Phage therapy is the clinical or veterinary application of bacterial viruses (bacteriophages) as antibacterial "drugs." More generally, phages can be used as biocontrol agents against plant as well as foodborne pathogens. In this chapter, we consider the therapeutic use of phage cocktails, which is the combining of two or more phage types to produce more pharmacologically diverse formulations. The primary motivation for the use of cocktails is their broader spectra of activity in comparison to individual phage isolates: they can impact either more bacterial types or achieve effectiveness under a greater diversity of conditions. The combining of phages can also facilitate better targeting of multiple strains making up individual bacterial species or covering multiple species that might be responsible for similar disease states, in general providing, relative to individual phage isolates, a greater potential for presumptive or empirical treatment. Contrasting the use of phage banks, or even phage isolation against specific etiologies that have been obtained directly from patients under treatment, here we consider the utility as well as potential shortcomings associated with the use of phage cocktails as therapeutic antibacterial agents.

  16. Bacteriophages as Potential Treatment for Urinary Tract Infections.

    Science.gov (United States)

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

    2016-01-01

    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. To investigate the effect of bacteriophages on Escherichia coli and Klebsiella pneumoniae strains isolated from the urine of patients suffering from UTIs. 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. 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. 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.

  17. PREPARATION OF CHEMICALLY WELL-DEFINED CARBOHYDRATE DENDRIMER CONJUGATES

    DEFF Research Database (Denmark)

    2004-01-01

    A method for the synthesis of dendrimer conjugates having a well-defined chemical structure, comprising one or more carbohydrate moieties and one or more immunomodulating substances coupled to a dendrimer, is presented. First, the carbohydrate is bound to the dendrimer in a chemoselective manner....... Subsequently, the immunomodulating substance is also bound in a chemoselective manner, to give a dendrimer conjugate with a well-defined structure and connectivity and containing a precise, pre-determined ratio of carbohydrate to immunomodulating substance. The invention also relates to novel dendrimer...

  18. Bacteriophages: back to the future

    Science.gov (United States)

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

  19. A Generic Synthesis Algorithm for Well-Defined Parametric Design

    NARCIS (Netherlands)

    Schotborgh, W.O.; Kokkeler, F.G.M.; Tragter, H.; Bomhoff, M.J.; Houten, van F.J.A.M.

    2008-01-01

    This paper aims to improve the way synthesis tools can be built by formalizing: 1) the design artefact, 2) related knowledge and 3) an algorithm to generate solutions. This paper focuses on well-defined parametric engineering design, ranging from machine elements to industrial products. A design art

  20. Well-defined transition metal hydrides in catalytic isomerizations.

    Science.gov (United States)

    Larionov, Evgeny; Li, Houhua; Mazet, Clément

    2014-09-07

    This Feature Article intends to provide an overview of a variety of catalytic isomerization reactions that have been performed using well-defined transition metal hydride precatalysts. A particular emphasis is placed on the underlying mechanistic features of the transformations discussed. These have been categorized depending upon the nature of the substrate and in most cases discussed following a chronological order.

  1. Well-defined (co)polypeptides bearing pendant alkyne groups

    KAUST Repository

    Zhao, Wei

    2016-03-18

    A novel metal-free strategy, using hydrogen-bonding catalytic ring opening polymerization of acetylene-functionalized N-carboxy anhydrites of α-amino acids, was developed for the synthesis of well-defined polypeptides bearing pendant alkyne groups. This method provides an efficient way to synthesize novel alkyne-functionalized homopolypeptides (A) and copolypeptides, such as AB diblock (B: non-functionalized), ABA triblock and star-AB diblock, as well as linear and star random copolypeptides, precursors of a plethora complex macromolecular architectures by click chemistry.

  2. Volumetric flame synthesis of well-defined molybdenum oxide nanocrystals.

    Science.gov (United States)

    Merchan-Merchan, Wilson; Saveliev, Alexei V; Desai, Milind

    2009-11-25

    Well-defined faceted inorganic Mo oxide nanocrystals are synthesized in the gas phase using a solid-fed-precursor flame synthesis method. The solid crystals have rectangular cross-section with characteristic size of 10-20 nm and with lengths ranging from 50 nm to a few hundred nanometres. A 1 mm diameter high purity Mo probe introduced in the oxygen-rich part of the flame serves as the material source. A combination of the strong temperature gradient and varying chemical species concentrations within the flame volume provides the ideal conditions for the rapid and direct formation of these unique nanocrystals. Oxidation and evaporation of MoO3 in the oxygen-rich zone are followed by reduction to MoO2 in the lower temperature, more fuel-rich zone. The MoO3 vapours formed are pushed in the direction of the gas flow and transformed into mature well-defined convex polyhedron nanocrystals bounded with six faces resembling rectangular parallelepipeds.

  3. Volumetric flame synthesis of well-defined molybdenum oxide nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Merchan-Merchan, Wilson; Desai, Milind [School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019 (United States); Saveliev, Alexei V, E-mail: wmerchan-merchan@ou.ed [Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695 (United States)

    2009-11-25

    Well-defined faceted inorganic Mo oxide nanocrystals are synthesized in the gas phase using a solid-fed-precursor flame synthesis method. The solid crystals have rectangular cross-section with characteristic size of 10-20 nm and with lengths ranging from 50 nm to a few hundred nanometres. A 1 mm diameter high purity Mo probe introduced in the oxygen-rich part of the flame serves as the material source. A combination of the strong temperature gradient and varying chemical species concentrations within the flame volume provides the ideal conditions for the rapid and direct formation of these unique nanocrystals. Oxidation and evaporation of MoO{sub 3} in the oxygen-rich zone are followed by reduction to MoO{sub 2} in the lower temperature, more fuel-rich zone. The MoO{sub 3} vapours formed are pushed in the direction of the gas flow and transformed into mature well-defined convex polyhedron nanocrystals bounded with six faces resembling rectangular parallelepipeds.

  4. Design and characterization of well-defined supramolecular polymers

    Science.gov (United States)

    Schaefer, Kathleen; Kade, Matthew; Hawker, Craig; Kramer, Edward

    2007-03-01

    Polymeric materials with well-defined and controllable temperature dependent properties are of interest both for technological applications and fundamental physical studies. Melt processing requires low viscosity, while resistance to fracture is desirable at material operating temperatures, and these two properties are often mutually exclusive. Through controlled radical polymerization (ATRP) we have synthesized tailor-made polymers with MHB groups specifically located at one or both chain ends or randomly along the backbone to provide thermal tunability, and by changing the nature of the MHB group (complementary or self-complementary) we can control the specificity and type of the polymer-polymer interaction. As a simple model system, we investigate the case of two end-functional MHB homopolymers that form a novel supramolecular diblock copolymer. Two energies are expected to be important in this system---χN, the Flory-Huggins interaction parameter times the degree of polymerization, which describes the polymer-polymer interaction, and ɛ, the binding energy of the MHB group. Using deuterium labeled polymers in various multilayer thin film structures, dynamic secondary ion mass spectrometry (dSIMS) allows each of these parameters to be measured independently and these values used to design technologically and physically interesting new materials.

  5. Bacteriophage-based Probiotic Preparation for Managing Shigella Infections

    Science.gov (United States)

    2015-04-16

    for a probiotic preparation – based on naturally occurring bacteriophages – as a way to condition the GI tract’s microflora gently and favorably...The preparation (designated “ShigActive”) is a bacteriophage cocktail that specifically targets Shigella spp. (significant diarrhea-causing pathogens...10-Apr-2013 Approved for Public Release; Distribution Unlimited Final Report: Bacteriophage -based Probiotic Preparation for Managing Shigella

  6. Bacteriophages as Potential Treatment for Urinary Tract Infections

    Science.gov (United States)

    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

  7. Staff Association Cocktail

    CERN Multimedia

    Staff Association

    2017-01-01

    The Staff Association has been organising for many years a cocktail with delegates of the Member States participating in Finance Committees of March and September. This cocktail is held at the end of the day, after the Finance Committee meeting. This direct and regular communication helps establish an ongoing contact between the Staff Association and CERN Member States and, more recently, the Associate Member States. Ambassadors of the CERN Staff Association, who are Members of the Personnel, have the opportunity to meet their national delegation in an informal and friendly atmosphere. These exchanges, facilitated by the use of the national language, allow the personnel via the Staff Association to express its ideas and positions on current affairs and fundamental issues, and also to hear about those of the delegations in return.

  8. Phage cocktails and the future of phage therapy.

    Science.gov (United States)

    Chan, Benjamin K; Abedon, Stephen T; Loc-Carrillo, Catherine

    2013-06-01

    Viruses of bacteria, known as bacteriophages or phages, were discovered nearly 100 years ago. Their potential as antibacterial agents was appreciated almost immediately, with the first 'phage therapy' trials predating Fleming's discovery of penicillin by approximately a decade. In this review, we consider phage therapy that can be used for treating bacterial infections in humans, domestic animals and even biocontrol in foods. Following an overview of the topic, we explore the common practice - both experimental and, in certain regions of the world, clinical - of mixing therapeutic phages into cocktails consisting of multiple virus types. We conclude with a discussion of the commercial and medical context of phage cocktails as therapeutic agents. In comparing off-the-shelf versus custom approaches, we consider the merits of a middle ground, which we deem 'modifiable'. Finally, we explore a regulatory framework for such an approach based on an influenza vaccine model.

  9. The effects of bacteriophage and nanoparticles on microbial processes

    Science.gov (United States)

    Moody, Austin L.

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

  10. Campylobacter bacteriophages and bacteriophage therapy.

    Science.gov (United States)

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

    2011-08-01

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

  11. Efficient Construction of Well-Defined Multicompartment Porous Systems in a Modular and Chemically Orthogonal Fashion.

    Science.gov (United States)

    Gao, Ning; Tian, Tian; Cui, Jiecheng; Zhang, Wanlin; Yin, Xianpeng; Wang, Shiqiang; Ji, Jingwei; Li, Guangtao

    2017-03-27

    A microfluidic assembly approach was developed for efficiently producing hydrogel spheres with reactive multidomains that can be employed as an advantageous platform to create spherical porous networks in a facile manner with well-defined multicompartments and spatiotemporally controlled functions. This strategy allows for not only large scale fabrication of various robust hydrogel microspheres with controlled size and porosity, but also the domains embedded in hydrogel network could be introduced in a modular manner. Additionally, the number of different domains and their ratio could be widely variable on demand. More importantly, the reactive groups distributed in individual domains could be used as anchor sites to further incorporate functional units in an orthogonal fashion, leading to well-defined multicompartment systems. The strategy provides a new and efficient route to construct well-defined functional multicompartment systems with great flexibility and extendibility. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Preparation of well-defined polystyrene/silica hybrid nanoparticles by ATRP

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Immobilization of the atom transfer radical polymerization(ATRP)macroinitiators at the silica nanoparticle surfaces was achieved through surface modification with excess toluene-2,4-diisocynate(TDI),after which the residual isocyanate groups were converted into ATRP macroinitiators.Structurally well-defined polystyrene chains were grown from the nanoparticle surfaces to yield individual particles composed of a silica core and a well-defined,densely grafted outer polystyrene by ATRP,which was initiated by the as-synthesized silica-based macroinitiator.FTIR,NMR and gel permeation chromatography(GPC)were used to characterize the polystyrene/silica hybrid particles.

  13. Preparation of well-defined polystyrene/silica hybrid nanoparticles by ATRP

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Immobilization of the atom transfer radical polymerization (ATRP) macroinitiators at the silica nanoparticle surfaces was achieved through surface modification with excess toluene-2,4-diisocynate (TDI), after which the residual isocyanate groups were converted into ATRP macroinitiators. Structurally well-defined polystyrene chains were grown from the nanoparticle surfaces to yield individual particles composed of a silica core and a well-defined, densely grafted outer polystyrene by ATRP, which was initiated by the as-synthesized silica-based macroinitiator. FTIR, NMR and gel permeation chro-matography (GPC) were used to characterize the polystyrene/silica hybrid particles.

  14. Effectiveness of lytic bacteriophages in reducing E. coli O157:H7 populations introduced through cross-contamination on fresh cut lettuce

    Science.gov (United States)

    Previous research has shown that lytic bacteriophages (phages) can kill E. coli O157:H7 on produce surfaces. 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) at 10^8 PFU/m...

  15. Well-Defined Dinuclear Gold Complexes for Preorganization-Induced Selective Dual Gold Catalysis

    NARCIS (Netherlands)

    Vreeken, V.; Broere, D.L.J.; Jans, A.C.H.; Lankelma, M.; Reek, J.N.H.; Siegler, M.A.; van der Vlugt, J.I.

    2016-01-01

    The synthesis, reactivity, and potential of well-defined dinuclear gold complexes as precursors for dual gold catalysis are explored. Using the preorganizing abilities of the ditopic (PNPiPr)-P-H (L-H) ligand, dinuclear Au-I-Au-I complex 1 and mixed-valent Au-I-Au-III complex 2 provide access to str

  16. Well-defined polynuclear heterobimetallic complexes as precursors for ceramic and magnetic materials.

    Science.gov (United States)

    Szafert, Sławomir; John, Lukasz; Sobota, Piotr

    2008-12-14

    Well-defined heterobi- and heteropolymetallic alkoxides are valuable precursors for numerous oxide materials with great application potential. Simple and high yield synthetic routes to such compounds are always highly desirable. This Perspective describes one of the methods that utilizes, as starting materials, homoleptic monometallic alkoxides with a free alcoholic moiety coordinated to the metal. The moiety constitutes a convenient anchor for upcoming organometallics.

  17. Well-defined temperature-sensitive surfactants for controlled emulsion coalescence

    NARCIS (Netherlands)

    Feng, Huanhuan; Verstappen, N.A.L.; Kuehne, A.J.C.; Sprakel, J.H.B.

    2013-01-01

    In a variety of applications, emulsion formulations are required, which exhibit excellent shelf stability yet can be broken or perform phase inversion at a desired time. Here we approach these contradictory constraints through the synthesis of well-defined thermoresponsive surfactants based on di(et

  18. Well-Defined Triblock Copolymer Containing Perfluoro- cyclobutyl Aryl Ether and Poly(acrylic acid) Segments

    Institute of Scientific and Technical Information of China (English)

    陆国林; 张森; 李永军; 黄晓宇

    2011-01-01

    A novel well-defined triblock copolymer containing perfluorocyclobutyl group was prepared by the combination of mechanism transformation strategy, thermal cycloaddition [2π+2π] polymerization and atom transfer radical polymerization (ATRP). Firstly, a macroinitiator with two ATRP initiating end groups was synthesized by thermal polymerization of 4,4'-bis-(trifluorovinyloxy)biphenyl (BTFVBP) and sequential end-capping with a difunctional compound containing trifluorovinyl and ATRP initiation group. Secondly, this macroinitiator initiated ATRP of t-butyl acrylate to synthesize PtBA-b-PBTFVBP-b-PtBA triblock copolymer. This copolymer was hydrolyzed to afford PAA-b-PBTFVBP-b-PAA amphiphilic triblock copolymer. This kind of fluorine-containing well-defined structure should benefit the study of self-assembly behaviors.

  19. Highly conductive single naphthalene and anthracene molecular junction with well-defined conductance

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chenyang [Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 W4-10, Ookayama, Meguro-ku, Tokyo 152-8551 (Japan); School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Kaneko, Satoshi; Komoto, Yuki; Fujii, Shintaro, E-mail: fujii.s.af@m.titech.ac.jp; Kiguchi, Manabu, E-mail: kiguti@chem.titech.ac.jp [Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 W4-10, Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

    2015-03-09

    We performed electronic investigation on single acene molecular junctions bridging Au-electrodes in ultra-high vacuum conditions using mechanically controllable break junction technique. While the molecular junctions displayed various conductance values at 100 K, they exhibited well-defined high conductance values (∼0.3 G{sub 0}) at 300 K, which is close to that of metal atomic contact. Direct π-binding of the molecules to the Au-electrodes leads to the high conductivities at the metal-molecule interface. At the elevated temperature, single molecular junctions trapped in local metastable structures can be fallen into energetically preferential more stable state and thus we fabricated structurally well-defined molecular junctions.

  20. Characterization and purification of bacteriophages using chromatofocusing.

    Science.gov (United States)

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

    2008-10-17

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

  1. Well-defined azazirconacyclopropane complexes supported on silica structurally determined by 2D NMR comparative elucidation

    KAUST Repository

    El Eter, Mohamad

    2013-01-01

    Grafting of Zr(NMe2)4 on mesoporous silica SBA-15 afforded selectively well-defined surface species SiOZr(NMe2) (η2NMeCH2). 2D solid-state NMR (1H- 13C HETCOR, Multiple Quantum) experiments have shown a unique structural rearrangement occurring on the immobilised zirconium bis methylamido ligand. © The Royal Society of Chemistry 2013.

  2. Well-defined polyethylene molecular brushes by polyhomologation and ring opening metathesis polymerization

    KAUST Repository

    Zhang, Hefeng

    2014-01-01

    A novel strategy using polyhomologation and ring opening metathesis polymerization (ROMP) has been developed for the synthesis of well-defined polyethylene (PE) molecular brushes. Polyhomologation was used to afford an OH-terminated PE, which after transformation to the norbornyl PE macromonomer was subjected to ROMP. Kinetics of ROMP of the PE macromonomer was studied by in situ1H NMR monitoring. The brush structure was proved from HT-GPC, 1H NMR and DSC results.

  3. Preparation of Bimetallic PtnPdm Supported Clusters with Well-Defined Stoichiometry

    Science.gov (United States)

    Rousset, J. L.; Cadrot, A. M.; Aires, F. Santos; Renouprez, A.; Mélinon, P.; Perez, A.; Pellarin, M.; Vialle, J. L.; Broyer, M.

    Supported bimetallic Pd-Pt clusters with a well-defined stoichiometry are produced using a laser-vaporization source. Free clusters are also studied by time-of-flight mass spectrometry and photofragmentation. The supported clusters are characterized by energy dispersive x-ray analysis. The low binding energy of palladium atoms compared to that of platinum is clearly demonstrated in both free and supported clusters. The reactivity is briefly discussed.

  4. Living Polycondensation: Synthesis of Well-Defined Aromatic Polyamide-Based Polymeric Materials

    KAUST Repository

    Alyami, Mram Z.

    2016-11-01

    Chain growth condensation polymerization is a powerful tool towards the synthesis of well-defined polyamides. This thesis focuses on one hand, on the synthesis of well-defined aromatic polyamides with different aminoalkyl pendant groups with low polydispersity and controlled molecular weights, and on the other hand, on studying their thermal properties. In the first project, well-defined poly (N-octyl-p-aminobenzoate) and poly (N-butyl-p-aminobenzoate) were synthesized, and for the first time, their thermal properties were studied. In the second project, ethyl4-aminobenzoate, ethyl 4-octyl aminobenzoate and 4-(hydroxymethyl) benzoic acid were used as novel efficient initiators of ε-caprolactone with t-BuP2 as a catalyst. Macroinitiator and Macromonomer of poly (ε-caprolactone) were synthesized with ethyl 4-octyl aminobenzoate and ethyl 4-aminobenzoate as initiators to afford polyamide-block-poly (ε-caprolactone) and polyamide-graft-poly (ε-caprolactone) by chain growth condensation polymerization (CGCP). In the third project, a new study has been done on chain growth condensation polymerization to discover the probability to synthesize new polymers and studied their thermal properties. For this purpose, poly (N-cyclohexyl-p-aminobenzoate) and poly (N-hexyl-p-aminobenzoate) were synthesized with low polydispersity and controlled molecular weights.

  5. LADDER SUPERSTRUCTURE-DIRECTED SYNTHESIS OF A WELL-DEFINED m-PHENELENEDIIMINO-BRIDGED LADDER POLYMETHYLSILOXANE

    Institute of Scientific and Technical Information of China (English)

    Yin-sheng Lv; Zhong-jie Ren; You-zhi Wan; Ping Xie; Rong-ben Zhang

    2009-01-01

    A well-defined m-phenylenediimino-bridged ladder polymethylsiloxane (LP) was first synthesized through a well-defined ladder superstructure (LS) acting as synthetic template, which was self-assembled by concerted interaction of hydrogen bonding and aromatic π-π stacking of the monomer (M), N,N'-bis(phenyldichlorosilyl)-m-phenylenediamine. Some key characterization data of LP and, in particular, the extremely vulnerable LS with very unstable Si--Cl and Si-N groups were given. The molecular weights (Mn) of LS and LP are 5010 and 10480, corresponding to about 15 and 46 monomer units, respectively. To monitor the real in situ status of LS in solution the XRD measurements of special freeze-drying samples were performed, demonstrating two characteristic peaks of ladder structure. Most importantly, both LP and LS display exceedingly sharp resonance absorption peaks with a half peak width (△1/2) as small as < 0.3 of MeSi(NH)O2/2 moieties in 29Si-NMR spectra. It is well-known that the higher the regularity of the ladder polysiloxane, the narrower the resonance peak of the siloxane moiety on the ladder backbone, and the smaller the half peak width △1/2. Therefore, the very small values of △1/2 for both LS and LP confirm that both LS and LP possess well-defined ladder structures.

  6. Effectiveness of bacteriophages in the sputum of cystic fibrosis patients.

    Science.gov (United States)

    Saussereau, E; Vachier, I; Chiron, R; Godbert, B; Sermet, I; Dufour, N; Pirnay, J-P; De Vos, D; Carrié, F; Molinari, N; Debarbieux, L

    2014-12-01

    Bacteriophages have been shown to be effective for treating acute infections of the respiratory tract caused by antibiotic-resistant bacteria in animal models, but no evidence has yet been presented of their activity against pathogens in complex biological samples from chronically infected patients. We assessed the efficacy of a cocktail of ten bacteriophages infecting Pseudomonas aeruginosa following its addition to 58 sputum samples from cystic fibrosis (CF) patients collected at three different hospitals. Ten samples that did not contain P. aeruginosa were not analysed further. In the remaining 48 samples, the addition of bacteriophages led to a significant decrease in the levels of P. aeruginosa strains, as shown by comparison with controls, taking two variables (time and bacteriophages) into account (p = 0.024). In 45.8% of these samples, this decrease was accompanied by an increase in the number of bacteriophages. We also tested each of the ten bacteriophages individually against 20 colonies from each of these 48 samples and detected bacteriophage-susceptible bacteria in 64.6% of the samples. An analysis of the clinical data revealed no correlation between patient age, sex, duration of P. aeruginosa colonization, antibiotic treatment, FEV1 (forced expiratory volume in the first second) and the efficacy of bacteriophages. The demonstration that bacteriophages infect their bacterial hosts in the sputum environment, regardless of the clinical characteristics of the patients, represents a major step towards the development of bacteriophage therapy to treat chronic lung infections. © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.

  7. Well-Defined Copper(I) Fluoroalkoxide Complexes for Trifluoroethoxylation of Aryl and Heteroaryl Bromides

    KAUST Repository

    Huang, Ronglu

    2015-03-17

    © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Copper(I) fluoroalkoxide complexes bearing dinitrogen ligands were synthesized and the structure and reactivity of the complexes toward trifluoroethoxylation, pentafluoropropoxylation, and tetrafluoropropoxylation of aryl and heteroaryl bromides were investigated. Efficiency drive: A series of copper(I) fluoroalkoxide complexes bearing N,N ligands have been prepared and structurally characterized. These well-defined complexes serve as efficient reagents for the fluoroalkoxylation of aryl and heteroaryl bromides to produce a wide range of trifluoroethyl, pentafluoropropyl, and tetrafluoropropyl (hetero)aryl ethers in good to excellent yields.

  8. Well-defined silica-supported zirconium–imido complexes mediated heterogeneous imine metathesis

    KAUST Repository

    Hamzaoui, Bilel

    2016-02-15

    Upon prolonged thermal exposure under vacuum, a well-defined single-site surface species [(≡Si-O-)Zr(NEt2)3] (1) evolves into an ethylimido complex [(≡Si-O-)Zr(=NEt)NEt2] (2). Reactions of 2 with an imine substrate result in imido/imine (=NRi, R: Et, Ph) exchange (metathesis) with the formation of [(≡Si-O-)Zr(=NPh)NEt2] (3). Compounds 2 and 3 effectively catalyze imine/imine cross-metathesis and are thus considered as the first heterogeneous catalysts active for imine metathesis. © The Royal Society of Chemistry 2016.

  9. Hollow silica capsules with well-defined asymmetric windows in the shell.

    Science.gov (United States)

    Zhao, Bo; Collinson, Maryanne M

    2012-05-15

    A straightforward and effective approach to fabricate porous silica capsules with well-defined asymmetric windows in the shell using raspberry-like templates has been developed. This process begins with the formation of a hierarchical template by chemically coupling a large polystyrene sphere to an ensemble of small, polystyrene latex spheres. The hierarchical template in conjunction with a hard templating method and spin-coating leads to silica capsules with well-defined, asymmetric pores (windows) in the outer shell. Proof-of-principle of this approach has been demonstrated using a 1500/110 nm hierarchical template. The silica capsules thus produced were characterized with scanning electron microscopy and STEM. The diameter of the capsules was ~1400 nm, and the outer opening of the windows was ~100 nm in size, consistent with the diameters of the core and satellite spheres considering the shrinkage due to the calcination. The inner opening was ~30 nm, which gives rise to an asymmetry factor, defined as the diameter of the outer window to the diameter of the inner window, of ~3. In another example, surface-bound capsules with an asymmetry factor of ~1 were made. Collectively, these windows can provide efficient pathways to connect the inside of the capsule to the outside and have potential for asymmetric diffusion and rectification.

  10. Large and well-defined Rabi splitting in a semiconductor nanogap cavity.

    Science.gov (United States)

    Uemoto, Mitsuharu; Ajiki, Hiroshi

    2014-09-22

    We propose a nanogap structure composed of semiconductor nanoparticles forming an optical cavity. The resonant excitation of excitons in the nanoparticles can generate a localized strong light field in the gap region, also called "hot spot". The spectral width of the hot spot is significantly narrow because of the small exciton damping and the dephasing at low temperature, so the semiconductor nanogap structure acts as a high-Q cavity. In addition, the interaction between light and matter at the nanogap is significantly larger than that in a conventional microcavity, because the former has a small cavity-mode volume beyond the diffraction limit. We theoretically demonstrate the large and well-defined vacuum-Rabi splitting of a two-level emitter placed inside the semiconductor nanogap cavity: the Rabi splitting energy of 1.7 meV for the transition dipole moment of the emitter (25 Debye) is about 6.3 times larger than the spectral width. An optical cavity providing such a large and well-defined Rabi splitting is highly suited for studying characteristic features of the cavity quantum electrodynamics and for the development of new applications.

  11. Challenging nature's monopoly on the creation of well-defined nanoparticles.

    Science.gov (United States)

    Jeong, Wonhee; Napier, Mary E; DeSimone, Joseph M

    2010-06-01

    Nature has selected and fine-tuned the physical and chemical properties of natural objects, such as size, shape, mechanical properties and surface chemistry, at the molecular level in order to modulate biological functions. A new particle fabrication process, particle replication in nonwetting templates (PRINT), has recently begun to attempt to emulate nature's ability to control those physical and chemical traits. The PRINT technology, which combines modern soft lithography with the unique properties of perfluoropolyether molds, enables the production of nanoparticles with unprecedented control of size, shape, chemical composition, deformability and surface functionality. This scalable 'top-down' fabrication process allows for the generation of well-defined nanostructures without the need for molecular assembly. The ability to flexibly engineer various matrix materials offers unique opportunities for the development of nanomedicines with desired functionality. The strength and versatility of PRINT makes it a powerful platform in nanomedicine for elucidating the role of physical and chemical properties of nanodelivery vehicles on the behavior and fate at the cellular, tissue and whole organism level. Utilizing the PRINT technology, we are generating well-defined nanomedicines with tailored properties for preclinical studies against a variety of human diseases.

  12. A SOF Damage Control Resuscitation Cocktail

    Science.gov (United States)

    2015-05-01

    resuscitation (DCR) cocktail for use by SOF’s that is capable of improving survival from polytrauma in austere settings. The cocktail components...components are tested in a combat-relevant swine polytrauma model of hemorrhagic shock with traumatic brain injury, free internal bleeding from an aortic...from polytrauma in austere settings. The cocktail components include Hextend for volume resuscitation and tissue perfusion, fibrinogen concentrate

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

    Science.gov (United States)

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

    2012-12-01

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

  14. Chlamydia bacteriophages.

    Science.gov (United States)

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

    2013-11-01

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

  15. Formation and stability of small well-defined Cu- and Ni oxide particles

    Energy Technology Data Exchange (ETDEWEB)

    Thalinger, Ramona [Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck (Austria); Heggen, Marc; Stroppa, Daniel G. [Ernst Ruska Zentrum und Peter Grünberg Institut, Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Stöger-Pollach, Michael [University Service Facility for Transmission Electron Microscopy (USTEM), Vienna University of Technology, A-1040 Vienna (Austria); Klötzer, Bernhard [Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck (Austria); Penner, Simon, E-mail: simon.penner@uibk.ac.at [Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck (Austria)

    2013-12-16

    Well-defined and -structured Cu/Cu{sub 2}O and Ni/NiO composite nanoparticles have been prepared by physical-vapor deposition on vacuum-cleaved NaCl(001) single crystal facets. Epitaxial growth has been observed due to the close crystallographic matching of the respective cubic crystal lattices. Distinct particle morphologies have only been obtained for the Ni/NiO particles, comprising truncated half-octahedral, rhombohedral- and pentagonal-shaped outlines. Oxidation of the particles in the temperature range 473–673 K in both cases led to the formation of well-defined CuO and NiO particles with distinct morphologies. Whereas CuO possibly adopts its thermodynamical equilibrium shape, NiO formation is accompanied by entering a Kirkendall-like state, that is, a hollow core–shell structure is obtained. The difference in the formation of the oxides is also reflected by their stability under reducing conditions. CuO transforms back to a polycrystalline mixture of Cu metal, Cu{sub 2}O and CuO after reduction in hydrogen at 673 K. In contrast, as expected from theoretical stability considerations, the formation of the hollow NiO structure is reversed upon annealing in hydrogen at 673 K and moreover results in the formation of a Ni-rich silicide structure Ni{sub 3}Si{sub 2}. The discussed systems present a convenient way to tackle and investigate various problems in nanotechnology or catalysis, including phase transformations, establishing structure/activity relationships or monitoring intermetallic particles, starting from well-defined and simple models. - Highlights: • Preparation of epitaxial Cu/Cu{sub 2}O and Ni/NiO composite nanoparticles on NaCl(001). • Distinct Ni/NiO particle morphologies. • Formation of well-shaped CuO and NiO particles upon oxidation. • Reversal of Kirkendall-NiO-state upon reduction/annealing in hydrogen.

  16. Hydrolases Part I: Enzyme Mechanism, Selectivity and Control in the Synthesis of Well-Defined Polymers

    Science.gov (United States)

    Veld, Martijn A. J.; Palmans, Anja R. A.

    Lipases are highly activity in the polymerization of a range of monomers. Both ring-opening polymerization of cyclic esters and polycondensation reactions of AA-BB and AB monomers have been investigated in great detail. This paper reviews the increased understanding in enzymatic strategies for the production of well-defined polymers. Major advantages of enzymatic catalysts are the relatively mild reaction conditions, and the often-observed excellent regio-, chemo-, and enantioselectivity that allow for the direct preparation of functional materials. However, as a result of the monomer activation mechanism, polymers of low polydispersity and low quantitative degree of endgroup functionality are difficult to attain. A wide variety of (co)polymers have been synthesized and explored in a variety of applications using lipase catalysts.

  17. Well-Defined Cyclic Triblock Terpolymers: A Missing Piece of the Morphology Puzzle

    KAUST Repository

    Polymeropoulos, George

    2016-10-27

    Two well-defined cyclic triblock terpolymers, missing pieces of the terpolymer morphology puzzle, consisting of poly(isoprene), polystyrene, and poly(2-vinylpyridine), were synthesized by combining the Glaser coupling reaction with anionic polymerization. An α,ω-dihydroxy linear triblock terpolymer (OH-PI1,4-b-PS-b-P2VP-OH) was first synthesized followed by transformation of the OH to alkyne groups by esterification with pentynoic acid and cyclization by Glaser coupling. The size exclusion chromatography (SEC) trace of the linear terpolymer precursor was shifted to lower elution time after cyclization, indicating the successful synthesis of the cyclic terpolymer. Additionally, the SEC trace of the cyclic terpolymer produced, after cleavage of the ester groups, shifted again practically to the position corresponding to the linear precursor. The first exploratory results on morphology showed the tremendous influence of the cyclic structure on the morphology of terpolymers. © 2016 American Chemical Society.

  18. Well-defined, nanometer-sized LiH cluster compounds stabilized by pyrazolate ligands.

    Science.gov (United States)

    Stasch, Andreas

    2014-01-27

    The assembly of well-defined large cluster compounds of ionic light metal hydrides is a synthetic challenge and of importance for synthesis, catalysis, and hydrogen storage. The synthesis and characterization of a series of neutral and anionic pyrazolate-stabilized lithium hydride clusters with inorganic cores in the nanometer region is now reported. These complexes were prepared in a bottom-up approach using alkyl lithium and lithium pyrazolate mixtures with silanes in hydrocarbon solutions. Structural characterization using synchrotron radiation revealed isolated cubic clusters that contain up to 37 Li(+) cations and 26 H(-) ions. Substituted pyrazolate ligands were found to occupy all corners and some edges for the anionic positions. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Well-defined silica-supported zirconium-imido complexes mediated heterogeneous imine metathesis.

    Science.gov (United States)

    Hamzaoui, Bilel; Pelletier, Jérémie D A; Abou-Hamad, Edy; Basset, Jean-Marie

    2016-03-28

    Upon prolonged thermal exposure under vacuum, a well-defined single-site surface species [([triple bond, length as m-dash]Si-O-)Zr(NEt2)3] () evolves into an ethylimido complex [([triple bond, length as m-dash]Si-O-)Zr([double bond, length as m-dash]NEt)NEt2] (). Reactions of with an imine substrate result in imido/imine ([double bond, length as m-dash]NRi, R: Et, Ph) exchange (metathesis) with the formation of [([triple bond, length as m-dash]Si-O-)Zr([double bond, length as m-dash]NPh)NEt2] (). Compounds and effectively catalyze imine/imine cross-metathesis and are thus considered as the first heterogeneous catalysts active for imine metathesis.

  20. Bottom-Up Engineering of Well-Defined 3D Microtissues Using Microplatforms and Biomedical Applications.

    Science.gov (United States)

    Lee, Geon Hui; Lee, Jae Seo; Wang, Xiaohong; Lee, Sang Hoon

    2016-01-07

    During the last decades, the engineering of well-defined 3D tissues has attracted great attention because it provides in vivo mimicking environment and can be a building block for the engineering of bioartificial organs. In this Review, diverse engineering methods of 3D tissues using microscale devices are introduced. Recent progress of microtechnologies has enabled the development of microplatforms for bottom-up assembly of diverse shaped 3D tissues consisting of various cells. Micro hanging-drop plates, microfluidic chips, and arrayed microwells are the typical examples. The encapsulation of cells in hydrogel microspheres and microfibers allows the engineering of 3D microtissues with diverse shapes. Applications of 3D microtissues in biomedical fields are described, and the future direction of microplatform-based engineering of 3D micro-tissues is discussed.

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

    Science.gov (United States)

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

    2013-01-01

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

  2. Well-Defined Silica Supported Aluminum Hydride: Another Step Towards the Utopian Single Site Dream?

    KAUST Repository

    Werghi, Baraa

    2015-07-17

    Reaction of triisobutylaluminum with SBA15700 at room temperature occurs by two parallel pathways involving either silanol or siloxane bridges. It leads to the formation of a well-defined bipodal [(≡SiO)2Al-CH2CH(CH3)2] 1a, silicon isobutyl [≡Si-CH2CH(CH3)2] 1b and a silicon hydride [≡Si-H] 1c. Their structural identity was characterized by FT-IR and advance solid-state NMR spectroscopies (1H, 13C, 29Si, 27Al and 2D multiple quantum), elemental and gas phase analysis, and DFT calculations. The reaction involves the formation of a highly reactive monopodal intermediate: [≡SiO-Al-[CH2CH(CH3)2]2], with evolution of isobutane. This intermediate undergoes two parallel routes: Transfer of either one isobutyl fragment or of one hydride to an adjacent silicon atom. Both processes occur by opening of a strained siloxane bridge, ≡Si-O-Si≡ but with two different mechanisms, showing that the reality of “single site” catalyst may be an utopia: DFT calculations indicate that isobutyl transfer occurs via a simple metathesis between the Al-isobutyl and O-Si bonds, while hydride transfer occurs via a two steps mechanism, the first one is a ß-H elimination to Al with elimination of isobutene, whereas the second is a metathesis step between the formed Al-H bond and a O-Si bond. Thermal treatment of 1a (at 250 °C) under high vacuum (10-5 mbar) generates Al-H through a ß-H elimination of isobutyl fragment. These supported well-defined Al-H which are highly stable with time, are tetra, penta and octa coordinated as demonstrated by IR and 27Al–1H J-HMQC NMR spectroscopy. All these observations indicate that surfaces atoms around the site of grafting play a considerable role in the reactivity of a single site system.

  3. Microwave-controlled facile synthesis of well-defined PbS hexapods.

    Science.gov (United States)

    Chen, Ganchao; Fan, Junbing; Zhao, Tian; Xu, Xiaobo; Zhu, Mingqiang; Tang, Zhiyong

    2011-09-01

    Controlled synthesis of well-defined PbS nanostructures in terms of size and shape has been strongly motivated by their potential applications ranging from solar photovoltaics to near-infrared optics. Hereby, we report a facile microwave-assistant method for ultrafast fabrication of PbS nanostructures, by which uniform PbS hexapods with six arms stretching along six (100) directions of the crystal seeds have been easily synthesized within minutes. Various morphologies including rectangle plates, uniform cubes as well as nanoparticles were obtained by tuning the parameters for the formation of PbS nanocrystals. The results reveal that both concentration and feed ratio of precursors determine the growth of PbS nanocrystals significantly. And higher initial precursor concentration favors the formation of the hexapod structures. The process of crystal growth is monitored through scanning electron microscopy of PbS from different durations of the reaction. This controlled ultrafast synthesis of PbS structures at nanometer and micrometer scale with various morphologies may be promising in large scale fabrication of nanostructures. Based on the systematically study of the growth process, a possible mechanism for the formation of the hexapod-like structure is discussed.

  4. Well-Defined Polyethylene-Based Random, Block, and Bilayered Molecular Cobrushes

    KAUST Repository

    Zhang, Hefeng

    2015-06-09

    Novel well-defined polyethylene-based random, block, and bilayered molecular cobrushes were synthesized through the macromonomer strategy. Two steps were involved in this approach: (i) synthesis of norbornyl-terminated macromonomers of polyethylene (PE), polycaprolactone (PCL), poly(ethylene oxide) (PEO), and polystyrene (PS), as well as polyethylene-b-polycaprolactone (PE-b-PCL), by esterification of the hydroxyl-terminated precursors (PE, PCL, PEO, PS, and PE-b-PCL) with 5-norbornene-2-carboxylic acid and (ii) ring-opening metathesis (co)polymerization of the resulting macromonomers to afford the PE-based molecular cobrushes. The PE-macromonomers were synthesized by polyhomologation of dimethylsulfoxonium methylide, while the others by anionic polymerization. Proton nuclear magnetic resonance spectroscopy (1H NMR) and high-temperature gel permeation chromatography (HT-GPC) were used to imprint the molecular characteristics of all macromonomers and molecular brushes and differential scanning calorimetry (DSC) for the thermal properties. The bilayered molecular cobrushes of P(PE-b-PCL) adopt a wormlike morphology on silica wafer as visualized by atomic force microscopy (AFM). © 2015 American Chemical Society.

  5. Inactivation of enzymes by organic solvents: New technique with well-defined interfacial area

    Energy Technology Data Exchange (ETDEWEB)

    Ghatorae, A.S.; Bell, G.; Halling, P.J. (Univ. of Strathclyde, Glasgow (United Kingdom))

    1994-02-20

    A liquid-liquid bubble column apparatus allows exposure of enzyme solutions to water-immiscible organic solvents with a known total interfacial area and well-defined time scales and flow. It allows clear distinction of the different classes of inactivation mechanism. With urease as a model enzyme, octan-2-one and butylbenzene act only through the effects of solvent molecules dissolved in the aqueous phase, giving first-order inactivation at 0.34 and 0.21 h[sup [minus]1], respectively. Hexane and tridecane act only through exposure to the interface. The amount of urease inactivated is proportional to the total area of interface exposed, rather than to elapsed time, and may be characterized by a rate of about 0.5 [mu]kat m[sup [minus]2]. This is consistent with the formation and inactivation of a complete adsorbed monolayer of protein. With butan-1-ol, both mechanisms contribute significantly to the observed inactivation. The presence of O[sub 2] increases the rate of interfacial inactivation, but not that by dissolved solvent.

  6. Synthesis, characterization and self-assembly of well-defined linear heptablock quaterpolymers

    KAUST Repository

    Ntaras, Christos

    2016-05-17

    Two well-defined heptablock quaterpolymers of the ABCDCBA type [Α: polystyrene (PS), B: poly(butadiene) with ∼90% 1,4-microstructure (PB1,4), C: poly(isoprene) with ∼55% 3,4-microstructure (PI3,4) and D: poly(dimethylsiloxane) (PDMS)] were synthesized by combining anionic polymerization high vacuum techniques and hydrosilylation/chlorosilane chemistry. All intermediates and final products were characterized by size exclusion chromatography, membrane osmometry, and proton nuclear magnetic resonance spectroscopy. Fourier transform infrared spectroscopy was used to further verify the chemical modification reaction of the difunctional PDMS. The self-assembly in bulk of these novel heptablock quarterpolymers, studied by transmission electron microscopy and small angle X-ray scattering, revealed 3-phase 4-layer alternating lamellae morphology of PS, PB1,4, and mixed PI3,4/PDMS domains. Differential scanning calorimetry was used to further confirm the miscibility of PI3,4 and PDMS blocks. It is the first time that PDMS is the central segment in such multiblock polymers (≥3 chemically different blocks). © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1443–1449. © 2016 Wiley Periodicals, Inc.

  7. Well-defined biobased segmented polyureas synthesis via a TBD-catalyzed isocyanate-free route.

    Science.gov (United States)

    Tang, Donglin; Mulder, Dirk-Jan; Noordover, Bart A J; Koning, Cor E

    2011-09-01

    Via an isocyanate-free route, a series of segmented polyureas (PUs) were synthesized from (potentially) renewable resources. To the best of our knowledge, the present work shows for the first time that the organic superbase guanidine 1,5,7-triazabicyclododecene (TBD) which was originally developed as a catalyst for the ring-opening polymerization of lactones, lactides or cyclic carbonates, is also a promising catalyst for the transurethanization between dicarbamates and diamino-terminated poly(propylene glycol) (PPGda) providing PUs via an isocyanate-free strategy. The renewable segmented PUs contain monodisperse hard segments (HSs). This well-defined structure was verified by the DMTA plots of the PUs, showing a sharp glass transition, a sharp flow transition and a flat rubbery plateau. The flow and maximum use temperature (Tfl ) of the PUs increases with the increasing number of urea groups in the corresponding dicarbamates. In addition, at constant HS length, the length of the soft-segment (SS) can be changed to adjust the properties of the PU materials, enabling their application as adhesives, soft elastomers, or rigid plastics.

  8. Correlation of Theory and Function in Well-Defined Bimetallic Electrocatalysts - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Crooks, Richard M.

    2014-06-05

    The objective of this research proposal was to correlate the structure of nanoparticles that are comprised of ~100-200 atoms to their electrocatalytic function. This objective was based on the growing body of evidence suggesting that catalytic properties can be tailored through controlled synthesis of nanoparticles. What has been missing from many of these studies, and what we are contributing, is a model catalyst that is sufficiently small, structurally well-defined, and well-characterized that its function can be directly predicted by theory. Specifically, our work seeks to develop a fundamental and detailed understanding of the relationship between the structure of nanoscopic oxygen-reduction catalysts and their function. We assembled a team with expertise in theory, synthesis, and advanced characterization methods to address the primary objective of this project. We anticipated the outcomes of the study to be: (1) a better theoretical understanding of how nanoparticle structure affects catalytic properties; (2) the development of advanced, in-situ and ex-situ, atomic-scale characterization methods that are appropriate for particles containing about 100 atoms; and (3) improved synthetic methods that produce unique nanoparticle structures that can be used to test theoretical predictions. During the project period, we have made excellent progress on all three fronts.

  9. The deficit is not a well-defined measure of fiscal policy.

    Science.gov (United States)

    Kotlikoff, L J

    1988-08-12

    Notwithstanding its widespread use, the government's deficit is not a well-defined measure of fiscal policy from the perspective of neoclassical economics; the equations of neoclassical models do not define the deficit. Rather than being a fundamental economic concept, the deficit is an arbitrary cash flow accounting construct with no necessary relation to the true stance of fiscal policy. Although the deficit is supposed to indicate how the burden of paying for the government's consumption is spread across different generations, actual changes in the measured deficit in the United States have had little if any relation to changes in the burden imposed by the government on different generations. The deficit's lack of definition is illustrated with a simple model, and the potential for misreading fiscal policy is discussed with U.S. fiscal policy in the 1980s as an example. In this article, creation of present value generational accounts are called for that would properly measure the intergenerational stance of fiscal policy.

  10. Synthesis and Complexation of Well-Defined Labeled Poly(N,N-dimethylaminoethyl methacrylates (PDMAEMA

    Directory of Open Access Journals (Sweden)

    Mark Billing

    2015-11-01

    Full Text Available We present the synthesis and characterization of well-defined polycationic copolymers containing thiazole dyes in the side chain. Atom transfer radical polymerization (ATRP was used for the copolymerization of 3-azidopropyl methacrylate (AzPMA and N,N-dimethylaminoethyl methacrylate (DMAEMA of different composition. Thiazole-based alkyne-functionalized dyes (e.g., 5-methyl-4-(prop-2-yn-1-yloxy-2-(pyridin-2-ylthiazole, (MPPT were afterwards covalently attached using copper catalyzed azide alkyne cycloadditions (CuAAC reaching contents of up to 9 mol % dye. Subsequent quaternization of the tertiary nitrogen of DMAEMA with strong methylation agents (e.g., methyl iodide led to permanently charged polyelectrolytes. The materials were characterized by size exclusion chromatography, as well as NMR- and UV/VIS-spectroscopy. Particular attention is paid to the spectroscopic properties of the dyes in the side chain upon environmental changes such as pH and salinity. We anticipate the application of such precisely functionalized polyelectrolytes as temperature- and pH-responsive sensors in biomedical applications, e.g., within interpolyelectrolyte complexes. Concerning the latter, first complex formation results are demonstrated.

  11. Measurement of (23)Na(n,2n) cross section in well-defined reactor spectra.

    Science.gov (United States)

    Košťál, Michal; Švadlenková, Marie; Baroň, Petr; Milčák, Ján; Mareček, Martin; Uhlíř, Jan

    2016-05-01

    The present paper aims to compare the calculated and experimental reaction rates of (23)Na(n,2n)(22)Na in a well-defined reactor spectra of a special core assembled in the LR-0 reactor. The experimentally determined reaction rate, derived using gamma spectroscopy of irradiated NaF sample, is used for average cross section determination. The resulting value averaged in spectra is 0.91±0.02µb. This cross-section is important as it is included in International Reactor Dosimetry and Fusion File and is also relevant to the correct estimation of long-term activity of Na coolant in Sodium Fast Reactors. The calculations were performed with the MCNP6 code using ENDF/B-VII.0, JEFF-3.1, JEFF-3.2, JENDL-3.3, JENDL-4, ROSFOND-2010 and CENDL-3.1 nuclear data libraries. Generally the best C/E agreement, within 2%, was found using the ROSFOND-2010 data set, whereas the worst, as high as 40%, was found using the ENDF/B-VII.0.

  12. Structure-function relationship of anticoagulant and antithrombotic well-defined sulfated polysaccharides from marine invertebrates.

    Science.gov (United States)

    Pomin, Vitor H

    2012-01-01

    Marine sulfated polysaccharides (MSPs), such as sulfated fucans (SFs), sulfated galactans (SGs), and glycosaminoglycans (GAGs) isolated from invertebrate animals, are highly anionic polysaccharides capable of interacting with certain cationic proteins, such as (co)-factors of the coagulation cascade during clotting-inhibition process. Primarily, these molecular complexes between MSPs and coagulation-related proteins seem to be driven mostly by electrostatic interactions. However, through a systematic comparison using several novel well-defined sulfated polysaccharides composed of repetitive oligosaccharides with clear sulfation patterns, it was proved that those molecular interactions are essentially regulated by the stereochemistry of the glycans (which depends on a conjunction of anomeric configurations, sugar types, conformational preferences, glycosylation, and sulfation sites), rather than just a mere consequence of the electronegative density charges (mainly from number of sulfate groups). Here, we present an overview about the structure-function relationship of the invertebrate MSPs with regular structures as potential anticoagulant and antithrombotic agents, as pathologies related to the cardiovascular system are one of the major causes of mortality in the world.

  13. Catalysis by Design: Well-Defined Single-Site Heterogeneous Catalysts

    KAUST Repository

    Pelletier, Jeremie

    2016-03-09

    ConspectusHeterogeneous catalysis, a field important industrially and scientifically, is increasingly seeking and refining strategies to render itself more predictable. The main issue is due to the nature and the population of catalytically active sites. Their number is generally low to very low, their "acid strengths" or " redox properties" are not homogeneous, and the material may display related yet inactive sites on the same material. In many heterogeneous catalysts, the discovery of a structure-activity reationship is at best challenging. One possible solution is to generate single-site catalysts in which most, if not all, of the sites are structurally identical. Within this context and using the right tools, the catalyst structure can be designed and well-defined, to reach a molecular understanding. It is then feasible to understand the structure-activity relationship and to develop predictable heterogeneous catalysis. Single-site well-defined heterogeneous catalysts can be prepared using concepts and tools of surface organometallic chemistry (SOMC). This approach operates by reacting organometallic compounds with surfaces of highly divided oxides (or of metal nanoparticles). This strategy has a solid track record to reveal structure-activity relationship to the extent that it is becoming now quite predictable. Almost all elements of the periodical table have been grafted on surfaces of oxides (from simple oxides such as silica or alumina to more sophisticated materials regarding composition or porosity).Considering catalytic hydrocarbon transformations, heterogeneous catalysis outcome may now be predicted based on existing mechanistic proposals and the rules of molecular chemistry (organometallic, organic) associated with some concepts of surface sciences. A thorough characterization of the grafted metal centers must be carried out using tools spanning from molecular organometallic or surface chemistry. By selection of the metal, its ligand set, and the

  14. Comparison of diagnostic tests in distinct well-defined conditions related to dry eye disease.

    Directory of Open Access Journals (Sweden)

    Monica Alves

    Full Text Available PURPOSE: This study compares signs, symptoms and predictive tools used to diagnose dry eye disease (DED and ocular surface disorders in six systemic well-defined and non-overlapping diseases. It is well known that these tests are problematic because of a lack of agreement between them in identifying these conditions. Accordingly, we provide here a comparative clinical profile analysis of these different diseases. METHODS: A spontaneous and continuous sample of patients with Sjögren's syndrome (SS (n=27, graft-versus-host-disease (GVHD (n=28, Graves orbitopathy (n=28, facial palsy (n=8, diabetes mellitus without proliferative retinopathy (n=14 and glaucoma who chronically received topical drugs preserved with benzalkonium chloride (n=20 were enrolled. Evaluation consisted of a comprehensive protocol encompassing: (1 structured questionnaire - Ocular Surface Disease Index (OSDI; (2 tear osmolarity (TearLab Osmolarity System - Ocusense; (3 tear film break-up time (TBUT; (4 fluorescein and lissamine green staining; (5 Schirmer test and (6 severity grading. RESULTS: One hundred and twenty five patients (aged 48.8 years-old ± 14.1, male:female ratio=0.4 were enrolled in the study, along with 24 age and gender matched controls. Higher scores on DED tests were obtained in Sjögren Syndrome (P<0.05, except for tear film osmolarity that was higher in diabetics (P<0.001 and fluorescein staining, that was higher in facial palsy (P<0.001. TFBUT and OSDI correlated better with other tests. The best combination of diagnostic tests for DED was OSDI, TBUT and Schirmer test (sensitivity 100%, specificity 95% and accuracy 99.3%. CONCLUSIONS: DED diagnostic test results present a broad range of variability among different conditions. Vital stainings and TBUT correlated best with one another whereas the best test combination to detect DED was: OSDI/TBUT/Schirmer.

  15. Cytochrome c Can Form a Well-Defined Binding Pocket for Hydrocarbons.

    Science.gov (United States)

    McClelland, Levi J; Steele, Harmen B B; Whitby, Frank G; Mou, Tung-Chung; Holley, David; Ross, J B Alexander; Sprang, Stephen R; Bowler, Bruce E

    2016-12-28

    Cytochrome c can acquire peroxidase activity when it binds to cardiolipin in mitochondrial membranes. The resulting oxygenation of cardiolipin by cytochrome c provides an early signal for the onset of apoptosis. The structure of this enzyme-substrate complex is a matter of considerable debate. We present three structures at 1.7-2.0 Å resolution of a domain-swapped dimer of yeast iso-1-cytochrome c with the detergents, CYMAL-5, CYMAL-6, and ω-undecylenyl-β-d-maltopyranoside, bound in a channel that places the hydrocarbon moieties of these detergents next to the heme. The heme is poised for peroxidase activity with water bound in place of Met80, which serves as the axial heme ligand when cytochrome c functions as an electron carrier. The hydroxyl group of Tyr67 sits 3.6-4.0 Å from the nearest carbon of the detergents, positioned to act as a relay in radical abstraction during peroxidase activity. Docking studies with linoleic acid, the most common fatty acid component of cardiolipin, show that C11 of linoleic acid can sit adjacent to Tyr67 and the heme, consistent with the oxygenation pattern observed in lipidomics studies. The well-defined hydrocarbon binding pocket provides atomic resolution evidence for the extended lipid anchorage model for cytochrome c/cardiolipin binding. Dimer dissociation/association kinetics for yeast versus equine cytochrome c indicate that formation of mammalian cytochrome c dimers in vivo would require catalysis. However, the dimer structure shows that only a modest deformation of monomeric cytochrome c would suffice to form the hydrocarbon binding site occupied by these detergents.

  16. A well-defined (POCOP)Rh catalyst for the coupling of aryl halides with thiols.

    Science.gov (United States)

    Timpa, Samuel D; Pell, Christopher J; Ozerov, Oleg V

    2014-10-22

    This article describes a well-defined pincer-Rh catalyst for C-S cross-coupling reactions. (POCOP)Rh(H)(Cl) serves as an active precatalyst for the coupling of aryl chlorides and bromides with aryl and alkyl thiols under reasonable conditions (3% mol cat., 110 °C, 2-24 h, >90% yield). For select substrates, >90% yields were obtained with catalyst loading as low as 0.1%. Key mechanistic intermediates have been isolated and fully characterized, including (POCOP)Rh(Ph)(SPh) (6a) and (POCOP)Rh(SPh2) (6b). The aryl/bis(phosphinite) (POCOP)Rh system has been shown to favor aryl thiolate reductive elimination at elevated temperatures and in some cases at room temperature, compared with the analogous diarylamido/bis(phosphine) (PNP)Rh pincer system. Concerted reductive elimination has been studied with 6a directly and in the presence of aryl bromide and aryl chloride traps. This investigation demonstrates a clear rate dependence on aryl chloride concentration during catalysis, a dependence that is absent when using aryl bromides. The rate of catalysis is dramatically reduced or brought to zero for ortho-tolyl halides, which can be traced to slower C-S coupling and slower carbon-halogen oxidative addition for ortho-substituted aryls. The influence of the sterics in the thiol component is less straightforward. The S-H oxidative addition product (POCOP)Rh(H)(SPh) (16) has been fully characterized and its reactivity has been examined, resulting in the isolation of the sodium-thiolate adduct (POCOP)Rh(NaSPh) (19). The solid-state structure of 19 shows Na interactions not only with sulfur, but also with a neighboring Rh and the chelating aryl carbon of the pincer framework. The reactivity of 16 and 19 indicates that these potential side products should not hinder catalysis.

  17. Osteogenic response of human mesenchymal stem cells to well-defined nanoscale topography in vitro

    Directory of Open Access Journals (Sweden)

    de Peppo GM

    2014-05-01

    Full Text Available Giuseppe Maria de Peppo,1–3 Hossein Agheli,2,3 Camilla Karlsson,2,3 Karin Ekström,2,3 Helena Brisby,3,4 Maria Lennerås,2,3 Stefan Gustafsson,3,5 Peter Sjövall,3,5,6 Anna Johansson,2,3 Eva Olsson,3,5 Jukka Lausmaa,3,6 Peter Thomsen,2,3 Sarunas Petronis3,6 1The New York Stem Cell Foundation Research Institute, New York, NY, USA; 2Department of Biomaterials, Sahlgrenska Academy, University of Gothenburg, 3BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, 4Department of Orthopaedics, Sahlgrenska Academy, University of Gothenburg, 5Applied Physics, Chalmers University of Technology, Göteborg, Sweden; 6Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden, Borås, Sweden Background: Patterning medical devices at the nanoscale level enables the manipulation of cell behavior and tissue regeneration, with topographic features recognized as playing a significant role in the osseointegration of implantable devices. Methods: In this study, we assessed the ability of titanium-coated hemisphere-like topographic nanostructures of different sizes (approximately 50, 100, and 200 nm to influence the morphology, proliferation, and osteogenic differentiation of human mesenchymal stem cells (hMSCs. Results: We found that the proliferation and osteogenic differentiation of hMSCs was influenced by the size of the underlying structures, suggesting that size variations in topographic features at the nanoscale level, independently of chemistry, can be exploited to control hMSC behavior in a size-dependent fashion. Conclusion: Our studies demonstrate that colloidal lithography, in combination with coating technologies, can be exploited to investigate the cell response to well defined nanoscale topography and to develop next-generation surfaces that guide tissue regeneration and promote implant integration. Keywords: colloidal lithography, nanotopography, human mesenchymal stem cells, cell proliferation, osteogenic

  18. Porous hydrogels with well-defined pore structure for biomaterials applications

    Science.gov (United States)

    Marshall, Andrew J.

    When any medical device is implanted inside the body, the natural inflammatory response causes the device to be encapsulated with a thin layer of dense, relatively avascular fibrous tissue, effectively sealing off the device from the surrounding tissue and isolating it from the rest of the body. For medical devices such as electrodes and glucose sensors, where functionality depends on the ability of the device to interact with the surrounding biochemistry, the "foreign body response" poses a formidable obstacle. Previous studies have demonstrated that porous materials with pore dimensions on the order of cell dimensions can induce a modified foreign body response, resulting in more vascularized capsule tissue. However, the utility of these studies is limited because the materials used had broad pore size distributions and poorly defined pore geometries. This thesis is motivated by the unavailability of biomaterials with well-defined and controlled pore size, and by the lack of understanding of the relationships between pore dimensions and the foreign body response. Our sphere templating technology permits the fabrication of open-pore structures with precisely controlled pore dimensions. We can produce these sphere-templated pore structures out of a variety of polymeric materials, including poly(2-hydroxyethyl methacrylate) (polyHEMA), silicone rubber, and degradable copolymers of polyHEMA and poly(epsilon-caprolactone). We applied our precision-engineered pore structures in vivo to investigate the role of pore size in the foreign body response. We implanted porous polyHEMA with various pore geometries under the skin of mice and found that the level of intra-pore vascularization increases with decreasing pore size, with vascular density directly proportional to the specific surface area of the implant, and that the threshold pore throat diameter for rapid tissue in-growth is approximately 8 mum. Based on our empirical results coupled with first principles, we

  19. Well-defined cholesterol polymers with pH-controlled membrane switching activity.

    Science.gov (United States)

    Sevimli, Sema; Inci, Fatih; Zareie, Hadi M; Bulmus, Volga

    2012-10-08

    Cholesterol has been used as an effective component of therapeutic delivery systems because of its ability to cross cellular membranes. Considering this, well-defined copolymers of methacrylic acid and cholesteryl methacrylate, poly(methacrylic acid-co-cholesteryl methacrylate) P(MAA-co-CMA), were generated as potential delivery system components for pH-controlled intracellular delivery of therapeutics. Statistical copolymers with varying cholesterol contents (2, 4, and 8 mol %) were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Dynamic light scattering (DLS) analysis showed that the hydrodynamic diameters of the copolymers in aqueous solutions ranged from 5 ± 0.3 to 7 ± 0.4 nm for the copolymers having 2 and 4 mol % CMA and 8 ± 1.1 to 13 ± 1.9 nm for the copolymer having 8 mol % CMA with increasing pH (pH 4.5-7.4). Atomic force microscopy (AFM) analysis revealed that the copolymer having 8 mol % CMA formed supramolecular assemblies while the copolymers having 2 and 4 mol % CMA existed as unimers in aqueous solution. The pH-responsive behavior of the copolymers was investigated via UV-visible spectroscopy revealing phase transitions at pH 3.9 for 2 mol % CMA, pH 4.7 for 4 mol % CMA, and pH 5.4 for 8 mol % CMA. Lipid bilayers and liposomes as models for cellular membranes were generated to probe their interactions with the synthesized copolymers. The interactions were determined in a pH-dependent manner (at pH 5.0 and 7.4) using surface plasmon resonance (SPR) spectroscopy and liposome leakage assay. Both the SPR analyses and liposome leakage assays indicated that the copolymer containing 2 mol % CMA displayed the greatest polymer-lipid interactions at pH 5.0, presenting the highest binding ability to the lipid bilayer surfaces, and also demonstrating the highest membrane destabilization activity. CellTiter-Blue assay showed that the copolymers did not affect the cell viability up to 30 μM over a period of 72 h.

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

    Science.gov (United States)

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

    2014-02-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2016-07-01

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

  3. Organometallic synthesis, reactivity and catalysis in the solid state using well-defined single-site species

    OpenAIRE

    Pike, Sebastian D.; Weller, Andrew S.

    2015-01-01

    Acting as a bridge between the heterogeneous and homogeneous realms, the use of discrete, well-defined, solid-state organometallic complexes for synthesis and catalysis is a remarkably undeveloped field. Here, we present a review of this topic, focusing on describing the key transformations that can be observed at a transition-metal centre, as well as the use of well-defined organometallic complexes in the solid state as catalysts. There is a particular focus upon gas–solid reactivity/catalys...

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Maia Merabishvili

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

  6. Bacteriophages infecting Propionibacterium acnes.

    Science.gov (United States)

    Brüggemann, Holger; Lood, Rolf

    2013-01-01

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

  7. Bacteriophages Infecting Propionibacterium acnes

    Directory of Open Access Journals (Sweden)

    Holger Brüggemann

    2013-01-01

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

  8. The use of lytic bacteriophages to reduce E. coli O157:H7 on fresh cut lettuce introduced through cross-contamination

    Science.gov (United States)

    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) at 108 PFU/ml or a control (phosphate buffered saline, PBS) was applied to lettuce by either 1) spraying on to lettuce piec...

  9. "Super" Cocktails for Heavy Ion Testing

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Michael B; Johnson, Michael B.; McMahan, Margaret A.; Galloway, Michelle; Leitner, Daniela; Morel, James R.; Gimpel, ThomasL.; Ninemire, Brien F.; Siero, Reba; Thatcher, Raymond K.

    2007-07-21

    The 4.5 MeV/nucleon heavy ion cocktail at the 88-Inch Cyclotron has been expanded by incorporating beams from solid material to fill in the linear energy transfer curve. This supercocktail is available by special request and is useful when only normal incidence between the beam and the device under test is possible or desirable.

  10. Bacteriophages and cancer.

    Science.gov (United States)

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

    2010-05-01

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

  11. Bacteriophages and Biofilms

    Science.gov (United States)

    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.

  12. Bacteriophages and Biofilms

    Directory of Open Access Journals (Sweden)

    David R. Harper

    2014-06-01

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

  13. Poly(2-acetoxyethyl methacrylate)/polystyrene latex interpenetrating polymer networks with well-defined phase-separated structure

    Institute of Scientific and Technical Information of China (English)

    Tao Wang; Shan Shi; Li Na Bian; Li Min Zhou; Li Qun Zhao; Shin Ichi Kuroda

    2011-01-01

    A series of poly (2-acetoxyethyl methacrylate)/polystyrene (PAEMA/PS) latex interpenetrating polymer networks (LIPNs) were prepared by seeded soap-free emulsion polymerization of styrene on the crosslinked PAEMA seed particles using an oil-soluble initiator. These PAEMA/PS LIPNs showed a well-defined phase-separated structure with PS phase dispersing in continuous PAEMA phase. The domain size of PS phase was found to depend on the crosslinking degree of PAEMA seed particles and the amount of second-stage styrene monomer.

  14. Development of a reference liquid scintillation cocktail

    CSIR Research Space (South Africa)

    Van Wyn Gaardt, WM

    2006-02-01

    Full Text Available of a scintillator dissolved in an organic solvent. The so-called scintillator solute is a material which emits a weak light flash or scintillation upon interaction with a certain quanta of radiation – the intensity of this scintillation being a... to prepare preliminary liquid scintillation cocktails. Figure 3: Maximum deviations observed between repeat measurements of the same source, displayed in red for Ultima Gold, green for XP, yellow for XI and blue for XPI. Figure 4: The counting...

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

    Science.gov (United States)

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

    2016-01-18

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

  16. Lipid mixtures prepared with well-defined synthetic ceramides closely mimic the unique stratum corneum lipid phase behavior.

    Science.gov (United States)

    de Jager, Miranda W; Gooris, Gert S; Ponec, Maria; Bouwstra, Joke A

    2005-12-01

    Lipid lamellae present in the outermost layer of the skin, the stratum corneum, form the main barrier for the diffusion of molecules through the skin. The presence of a unique 13 nm lamellar phase and its high crystallinity are characteristic for the stratum corneum lipid phase behavior. In the present study, small-angle and wide-angle X-ray diffraction were used to examine the organization in lipid mixtures prepared with a unique set of well-defined synthetic ceramides, varying from each other in head group architecture and acyl chain length. The results show that equimolar mixtures of cholesterol, free fatty acids, and synthetic ceramides (resembling the composition of pig ceramides) closely resemble the lamellar and lateral stratum corneum lipid organization, both at room and higher temperatures. Exclusion of several ceramide classes from the mixture does not affect the lipid organization. However, complete substitution of ceramide 1 (acylceramide with a sphingosine base) with ceramide 9 (acylceramide with a phytosphingosine base) reduces the formation of the long periodicity lamellar phase. This indicates that the head group architecture of acylceramides affects the lipid organization. In conclusion, lipid mixtures prepared with well-defined synthetic ceramides offer an attractive tool with which to unravel the importance of the molecular structure of individual ceramides for proper lipid organization.

  17. Measurement and calculation of fast neutron and gamma spectra in well defined cores in LR-0 reactor.

    Science.gov (United States)

    Košťál, Michal; Matěj, Zdeněk; Cvachovec, František; Rypar, Vojtěch; Losa, Evžen; Rejchrt, Jiří; Mravec, Filip; Veškrna, Martin

    2017-02-01

    A well-defined neutron spectrum is essential for many types of experimental topics and is also important for both calibration and testing of spectrometric and dosimetric detectors. Provided it is well described, such a spectrum can also be employed as a reference neutron field that is suitable for validating selected cross sections. The present paper aims to compare calculations and measurements of such a well-defined spectra in geometrically similar cores of the LR-0 reactor with fuel containing slightly different enrichments (2%, 3.3% and 3.6%). The common feature to all cores is a centrally located dry channel which can be used for the insertion of studied materials. The calculation of neutron and gamma spectra was realized with the MCNP6 code using ENDF/B-VII.0, JEFF-3.1, JENDL-3.3, ROSFOND-2010 and CENDL-3.1 nuclear data libraries. Only minor differences in neutron and gamma spectra were found in the comparison of the presented reactor cores with different fuel enrichments. One exception is the gamma spectrum in the higher energy region (above 8MeV), where more pronounced variations could be observed.

  18. Efficient removal of formaldehyde by nanosized gold on well-defined CeO₂ nanorods at room temperature.

    Science.gov (United States)

    Xu, Quanlong; Lei, Wanying; Li, Xinyang; Qi, Xiaoying; Yu, Jiaguo; Liu, Gang; Wang, Jinlong; Zhang, Pengyi

    2014-08-19

    Gold (Au) nanoparticles (NPs) supported on well-defined ceria (CeO2) nanorods with exposed {110} and {100} facets were prepared by a deposition-precipitation method and characterized by powder X-ray diffraction, micro-Raman spectroscopy, X-ray photoelectron spectroscopy, nitrogen adsorption-desorption, transmission electron microscopy, high-resolution transmission electron microscopy, and high-angle annular dark-field scanning transmission electron microscopy. Both nanometer and subnanometer gold particles were found to coexist on ceria supports with various Au contents (0.01-5.4 wt %). The catalytic performance of Au/CeO2 catalysts was examined for formaldehyde (HCHO) oxidation into CO2 and H2O at room temperature and shown to be Au content dependent, with 1.8 wt % Au/CeO2 displaying the best performance. On the basis of the results from hydrogen temperature-programmed reduction and in situ Fourier transform infrared spectroscopy observations, the high reactivity and stability of Au/CeO2 catalysts is mainly attributed to the well-defined ceria nanorods with {110} and {100} facets which present a relatively low energy for oxygen vacancy formation. Furthermore, gold NPs could induce the weakened Ce-O bond which in turn promotes HCHO oxidation.

  19. In Situ SIMS and IR Spectroscopy of Well-Defined Surfaces Prepared by Soft Landing of Mass-Selected Ions

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Grant E.; Gunaratne, Kalupathirannehelage Don D.; Laskin, Julia

    2014-06-16

    Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of materials that are inaccessible using conventional synthesis techniques. Coupling soft landing with in situ characterization using secondary ion mass spectrometry (SIMS) and infrared reflection absorption spectroscopy (IRRAS) enables analysis of well-defined surfaces under clean vacuum conditions. The capabilities of three soft-landing instruments constructed in our laboratory are illustrated for the representative system of surface-bound organometallics prepared by soft landing of mass-selected ruthenium tris(bipyridine) dications, [Ru(bpy)3]2+, onto carboxylic acid terminated self-assembled monolayer surfaces on gold (COOH-SAMs). In situ time-of-flight (TOF)-SIMS provides insight into the reactivity of the soft-landed ions. In addition, the kinetics of charge reduction, neutralization and desorption occurring on the COOH-SAM both during and after ion soft landing are studied using in situ Fourier transform ion cyclotron resonance (FT-ICR)-SIMS measurements. In situ IRRAS experiments provide insight into how the structure of organic ligands surrounding metal centers is perturbed through immobilization of organometallic ions on COOH-SAM surfaces by soft landing. Collectively, the three instruments provide complementary information about the chemical composition, reactivity and structure of well-defined species supported on surfaces.

  20. Fulleretic Well-Defined Scaffolds: Donor-Fullerene Alignment Through Metal Coordination and Its Effect on Photophysics.

    Science.gov (United States)

    Williams, Derek E; Dolgopolova, Ekaterina A; Godfrey, Danielle C; Ermolaeva, Evgeniya D; Pellechia, Perry J; Greytak, Andrew B; Smith, Mark D; Avdoshenko, Stanislav M; Popov, Alexey A; Shustova, Natalia B

    2016-07-25

    Herein, we report the first example of a crystalline metal-donor-fullerene framework, in which control of the donor-fullerene mutual orientation was achieved through chemical bond formation, in particular, by metal coordination. The (13) C cross-polarization magic-angle spinning NMR spectroscopy, X-ray diffraction, and time-resolved fluorescence spectroscopy were performed for comprehensive structural analysis and energy-transfer (ET) studies of the fulleretic donor-acceptor scaffold. Furthermore, in combination with photoluminescence measurements, the theoretical calculations of the spectral overlap function, Förster radius, excitation energies, and band structure were employed to elucidate the photophysical and ET processes in the prepared fulleretic material. We envision that the well-defined fulleretic donor-acceptor materials could contribute not only to the basic science of fullerene chemistry but would also be used towards effective development of organic photovoltaics and molecular electronics.

  1. Synthesis and Characterization of Well-Defined Regular Star Polyisoprenes with 3, 4, 6 and 8 Arms

    KAUST Repository

    Ratkanthwar, Kedar R.

    2013-01-01

    Three series of regular well-defined star polyisoprenes (PIs) with 3, 4 and 6 arms (each series: same arm molecular weight) have been synthesized by anionic polymerization high vacuum techniques and chlorosilane chemistry. In addition, three linear PIs with practically the double arm molecular weight of the corresponding series (2-arm star PIs) have been synthesized, as well as one 8-arm star PI. All intermediate (arms) and final (stars) products have been characterized by size exclusion chromatography (SEC), SEC-multi-angle laser light scattering (SEC-MALLS) and nuclear magnetic resonance (NMR) spectroscopy. The Tg of the star PIs was determined by differential scanning calorimetry. These model polymeric materials are essential for polymer physics and polymer physical chemistry in order to establish the structure/property relationships.

  2. Self-assembly behavior of well-defined polymethylene-block-poly(ethylene glycol) copolymers in aqueous solution

    KAUST Repository

    Alkayal, Nazeeha

    2016-09-22

    A series of well-defined amphiphilic polymethylene-b-poly(ethylene glycol) (PM-b-PEG) diblock copolymers, with different hydrophobic chain length, were synthesized by combining Diels-Alder reaction with polyhomologation. The successful synthetic procedure was confirmed by size-exclusion chromatography (SEC) and 1H NMR spectroscopy. These block copolymers self-assembled into spherical micelles in aqueous solutions and exhibit low critical micelle concentration (CMC) of 2–4 mg/mL, as determined by fluorescence spectroscopy using pyrene as a probe. Measurements of the micelle hydrodynamic diameters, performed by dynamic light scattering (DLS), cryo-transmission electron microscopy (cryo-TEM) and atomic force microscopy (AFM), revealed a direct dependence of the micelle size from the polymethylene block length.

  3. Acyclic Diene Metathesis (ADMET Polymerization for Precise Synthesis of Defect-Free Conjugated Polymers with Well-Defined Chain Ends

    Directory of Open Access Journals (Sweden)

    Tahmina Haque

    2015-03-01

    Full Text Available This accounts introduces unique characteristics by adopting the acyclic diene metathesis (ADMET polymerization for synthesis of conjugated polymers, poly(arylene vinylenes, known as promising molecular electronics. The method is more suitable than the other methods in terms of atom efficiency affording defect-free, stereo-regular (exclusive trans polymers with well-defined chain ends; the resultant polymers possess better property than those prepared by the conventional methods. The chain ends (vinyl group in the resultant polymer prepared by ruthenium-carbene catalyst(s can be modified by treating with molybdenum-alkylidene complex (olefin metathesis followed by addition of various aldehyde (Wittig type cleavage, affording the end-functionalized polymers exclusively. An introduction of initiating fragment, the other conjugated segment, and one-pot synthesis of end-functionalized block copolymers, star shape polymers can be achieved by adopting this methodology.

  4. Photometric characterization of a well defined sample of isolated galaxies in the context of the AMIGA project

    CERN Document Server

    Durbala, A; Buta, R; Verdes-Montenegro, L

    2008-01-01

    We perform a detailed photometric analysis (bulge-disk-bar decomposition and Concentration-Asymmetry-Clumpiness - CAS parametrization) for a well defined sample of isolated galaxies, extracted from the Catalog of Isolated Galaxies (Karachentseva 1973) and reevaluated morphologically in the context of the AMIGA project. We focus on Sb-Sc morphological types, as they are the most representative population among the isolated spiral galaxies. Assuming that the bulge Sersic index and/or Bulge/Total luminosity ratios are reasonable diagnostics for pseudo- versus classical bulges, we conclude that the majority of late-type isolated disk galaxies likely host pseudobulges rather than classical bulges. Our parametrization of galactic bulges and disks suggests that the properties of the pseudobulges are strongly connected to those of the disks. This may indicate that pseudobulges are formed through internal processes within the disks (i.e. secular evolution) and that bars may play an important role in their formation. A...

  5. Structure of branching enzyme- and amylomaltase modified starch produced from well-defined amylose to amylopectin substrates

    DEFF Research Database (Denmark)

    Sorndecha, Waraporn; Sagnelli, Domenico; Meier, Sebastian

    2016-01-01

    Thermostable branching enzyme (BE, EC 2.4.1.18) from Rhodothermus obamensis in combination with amylomaltase (AM, EC 2.4.1.25) from Thermus thermophilus was used to modify starch structure exploring potentials to extensively increase the number of branch points in starch. Amylose is an important...... constituent in starch and the effect of amylose on enzyme catalysis was investigated using amylose-only barley starch (AO) and waxy maize starch (WX) in well-defined ratios. All products were analysed for amylopectin chain length distribution, α-1,6 glucosidic linkages content, molar mass distribution...... by the molar mass rather that the branching density of the glucan per se . Our data demonstrate that a higher amylose content in the substrate starch efficiently produces α-1,6 glucosidic linkages and that the present of amylose generates a higher Μw and more resistant product than amylopectin. The combination...

  6. Well-Defined Molybdenum Oxo Alkyl Complex Supported on Silica by Surface Organometallic Chemistry: A Highly Active Olefin Metathesis Precatalyst.

    Science.gov (United States)

    Merle, Nicolas; Le Quéméner, Frédéric; Bouhoute, Yassine; Szeto, Kai C; De Mallmann, Aimery; Barman, Samir; Samantaray, Manoja K; Delevoye, Laurent; Gauvin, Régis M; Taoufik, Mostafa; Basset, Jean-Marie

    2017-02-15

    The well-defined silica-supported molybdenum oxo alkyl species (≡SiO-)MoO(CH2(t)Bu)3 was selectively prepared by grafting of MoO(CH2(t)Bu)3Cl onto partially dehydroxylated silica (silica700) using the surface organometallic chemistry approach. This surface species was fully characterized by elemental analysis and DRIFT, solid-state NMR, and EXAFS spectroscopy. This new material is related to the active species of industrial supported MoO3/SiO2 olefin metathesis catalysts. It displays very high activity in propene self-metathesis at mild (turnover number = 90 000 after 25 h). Remarkably, its catalytic performance outpaces those of the parent imido derivative and its tungsten oxo analogue.

  7. A versatile nanobuilding precursor for the effective architecture of well-defined organic/inorganic hybrid via click chemistry

    Institute of Scientific and Technical Information of China (English)

    Ya Kun Zhu; Shan Yi Guang; Hong Yao Xu

    2012-01-01

    A novel octazido substituted nanobuilding precursor,octakis[dimethy(p-azidomethylene)siloxyl]octasilsesquioxane (ODA),was prepared by the conventional diazo-transfer reaction of octakis[dimethy(p-chloromethylene)silyl]octasilsesquioxane (ODC)with NaN3,and its structure was characterized by FT-IR,1H,13C,29Si NMR and MALDI-TOF MS,respectively.The structural rearrangement of POSS core in the synthesis strategy of ODA developed in this work was effectively prohibited in comparison with traditionary azidization process.The resultant ODA was not only soluble in common solvents such as CHCl3,THF,toluene,DMF and DMSO,but also could effectively serve as a versatile nanobuilding precursor for the architecture of well-defined organicinorganic hybrids via click chemistry.

  8. Kumada chain-growth polycondensation as a universal method for synthesis of well-defined conjugated polymers

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Kumada chain-growth polycondensation (KCGP) is a novel method for the synthesis of well-defined conjugated polymers.Because the Ni-catalyst can transfer in an intramolecular process to the propagating chain end,the polymerization follows chain-growth mechanism.With this newly developed method,various conjugated polymers,such as polythiophenes,poly(p-phenylene) (PPP),polypyrrole (PPy),and polyfluorene with controlled molecular weights and relatively narrow polydispersities (PDIs),have been prepared.Especially,the polymerizations for poly(3-alkylthiophene)s (P3ATs),PPP,and PPy exhibited quasi-living characteristics,which allows preparing polymer brushes,fully-conjugated block copolymers,and macroinitiators and macro-reactants for the synthesis of rod-coil block copolymers.In the current review,the progress in this new area is summarized.

  9. Bacteriophage therapy against Enterobacteriaceae

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

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

  10. Bacteriophage therapy against Enterobacteriaceae.

    Science.gov (United States)

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

    2015-02-01

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

  11. Hyperexpansion of RNA Bacteriophage Diversity

    Science.gov (United States)

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

    2016-01-01

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

  12. Hyperexpansion of RNA Bacteriophage Diversity.

    Directory of Open Access Journals (Sweden)

    Siddharth R Krishnamurthy

    2016-03-01

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

  13. Hyperexpansion of RNA Bacteriophage Diversity.

    Science.gov (United States)

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

    2016-03-01

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

  14. Cocktail effects on biomarker responses in fish

    Energy Technology Data Exchange (ETDEWEB)

    Celander, Malin C., E-mail: malin.celander@zool.gu.se [University of Gothenburg, Department of Zoology, Box 463, SE-405 30 Gothenburg (Sweden)

    2011-10-15

    One of today's greatest challenges in environmental toxicology is to understand effects of mixture toxicity, commonly referred to as cocktail effects, in humans and in wildlife. Biomarker responses in fish are routinely used to assess exposure of anthropogenic chemicals in the aquatic environment. However, little is known about how cocktail effects affect these biomarker responses. For this reason, there is an obvious risk for misinterpretation of biomarker-data and this can have profound negative effects on stakeholder's decisions and actions, as well as on legislations and remediation-plans initiated in order to reduce exposure to certain chemicals. Besides, chemical safety-levels are traditionally based on experiences from lab-studies with single chemicals, which is unfortunate as a chemical can be more toxic when it is mixed with other chemicals, because of the cocktail effect. This review focuses on pharmacokinetic interactions between different classes of pollutants on detoxification mechanisms and how that affects two commonly used biomarkers in the aquatic environment: (1) induction of cytochrome P450 1A (CYP1A) that is mediated via activation of the arylhydrocarbon receptor (AhR), used to assess exposure to aromatic hydrocarbons; (2) induction of vitellogenin (VTG) that is mediated via activation of the estrogen receptor (ER), used to assess exposure to estrogenic chemicals. These responses can be either directly or indirectly affected by the presence of other classes of pollutants as a result of cocktail effects. For example, chemicals that inhibit the function of key metabolic enzymes and transporter pumps that are involved in elimination of AhR- and ER agonists, can result in bioaccumulation of aromatic hydrocarbons and estrogenic chemicals resulting in increased biomarker responses. This cocktail effect can lead to overestimation of the actual exposure pressure. On the contrary, induction of expression of key metabolic enzymes and transporter

  15. The cosmic cocktail three parts dark matter

    CERN Document Server

    Freese, Katherine

    2014-01-01

    The ordinary atoms that make up the known universe-from our bodies and the air we breathe to the planets and stars-constitute only 5 percent of all matter and energy in the cosmos. The rest is known as dark matter and dark energy, because their precise identities are unknown. The Cosmic Cocktail is the inside story of the epic quest to solve one of the most compelling enigmas of modern science - what is the universe made of? - told by one of today's foremost pioneers in the study of dark matter. Blending cutting-edge science with her own behind-the-scenes insights as a leading researcher in the

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

    Directory of Open Access Journals (Sweden)

    Andrey A Filippov

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

  17. Chlamydial plasmids and bacteriophages.

    Science.gov (United States)

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

    2015-01-01

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

  18. Bacteriophages of Clostridium perfringens

    Science.gov (United States)

    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...

  19. Well-defined linear Au n (n = 2-4) chains encapsulated in SWCNTs: a DFT study.

    Science.gov (United States)

    Liu, Yiliang; Hua, Yawen; Yan, Anying; Wu, Shuang; Kong, Fanjie

    2017-01-01

    One-dimensional (1D) gold nanostructures have been extensively studied due to their potential applications in nanoelectronic devices. Using first-principles calculations, composites consisting of a well-defined linear Au n (n = 2-4) chain encapsulated in a (9,0) single-walled carbon nanotube (SWCNT) were studied. The translational energy barrier of a single Au atom in a (9,0) SWCNT was found to be 0.03 eV. This low barrier guaranteed the formation of Au n @ (9,0) SWCNT (n = 1-4) composites. Bond lengths, differential charge densities, and electronic band structures of the composites were studied. The average Au-Au bond lengths in the composites were found to be almost the same as those in the corresponding free-standing linear Au n . The average bond length increased as the number of Au atoms increased. Charge transfer in all of these composites was slight, although a few valence electrons were transferred from the (9,0) SWCNT and the Au chains to intercalations. The conductivities of the encapsulated linear Au n (n = 2-4) chains were enhanced to some extent by encapsulating them in the SWCNT.

  20. Design and synthesis of structurally well-defined functional polypropylenes via transition metal-mediated olefin polymerization chemistry

    Institute of Scientific and Technical Information of China (English)

    Dong Jinyong

    2006-01-01

    Functionalization of polyolefins is an industrially important yet scientifically challenging research subject.This paper summarizes our recent effort to access structurally well-defined functional polypropylenes via transition metal-mediated olefin polymerization.In one approach,polypropylenes containing side chain functional groups of controlled concentrations were obtained by Ziegler-Natta-catalyzed copolymerization of propylene in combination with either living anionic or controlled radical polymerization of polar monomers.The copolymerization of propylene with 1,4-divinylbenzene using an isospecific MgC12-supported TIC14 catalyst yielded potypropylenes containing pendant styrene moieties.Both metalation reaction with n-butyllithium and hydrochlorination reaction with dry hydrogen chloride selectively and quantitatively occurred at the pendant reactive sites,generating polymeric benzyllithium and 1-chloroethylbenzene species.These species initiated living anionic polymerization of styrene(S)and atom transfer radical polymerization(in the presence of CuC1 and pentamethyldiethylenetriamine) of methyl methacrylate(MMA),respectively,resulting in functional polypropylene graft copolymers(PP-g-PS and PP-g-PMMA)with controllable graft lengths.In another approach,chain end-functionalized polypropylenes containing a terminal OH-group with controlled molecular weights were directly prepared by propylene polymerization with a metaUocene catalyst through a selective aluminum chain transfer reaction.Both approaches proved to be desirable polyolefin functionalization routes in terms of efficiency and polymer structure controllability.

  1. A Well-Defined Readily Releasable Pool with Fixed Capacity for Storing Vesicles at Calyx of Held.

    Science.gov (United States)

    Mahfooz, Kashif; Singh, Mahendra; Renden, Robert; Wesseling, John F

    2016-04-01

    The readily releasable pool (RRP) of vesicles is a core concept in studies of presynaptic function. However, operating principles lack consensus definition and the utility for quantitative analysis has been questioned. Here we confirm that RRPs at calyces of Held from 14 to 21 day old mice have a fixed capacity for storing vesicles that is not modulated by Ca2+. Discrepancies with previous studies are explained by a dynamic flow-through pool, established during heavy use, containing vesicles that are released with low probability despite being immediately releasable. Quantitative analysis ruled out a posteriori explanations for the vesicles with low release probability, such as Ca2+-channel inactivation, and established unexpected boundary conditions for remaining alternatives. Vesicles in the flow-through pool could be incompletely primed, in which case the full sequence of priming steps downstream of recruitment to the RRP would have an average unitary rate of at least 9/s during heavy use. Alternatively, vesicles with low and high release probability could be recruited to distinct types of release sites; in this case the timing of recruitment would be similar at the two types, and the downstream transition from recruited to fully primed would be much faster. In either case, further analysis showed that activity accelerates the upstream step where vesicles are initially recruited to the RRP. Overall, our results show that the RRP can be well defined in the mathematical sense, and support the concept that the defining mechanism is a stable group of autonomous release sites.

  2. Well-defined Polymethylene-Based Co/Terpolymers by Combining Anthracene/Maleimide Diels-Alder Reaction with Polyhomologation

    KAUST Repository

    Hadjichristidis, Nikolaos

    2015-05-26

    A novel strategy towards well-defined polymethylene-based co/terpolymers, by combining anthracene/maleimide Diels-Alder reaction with polyhomologation, is presented. For the synthesis of diblock copolymers the following approach was applied: a) synthesis of α-anthracene-ω-hydroxy- polymethylene by polyhomologation using tri (9-anthracene-methyl propyl ether) borane as initiator, b) synthesis of furan-protected-maleimide-terminated poly (ε-caprolactone) or polyethylene glycol and c). Diels-Alder reaction between the anthracene and maleimide-terminated polymers. In the case of triblock terpolymers the α-anthracene-ω-hydroxy-polymethylene was used as macroinitiator for the ring-opening polymerization of D, L-lactide to afford an anthracene-terminated PM-b-PLA copolymer, followed by Diels-Alder reaction with furan-protected maleimide-terminated poly (ε-caprolactone) or polyethylene glycol to give the triblock terpolymers. All intermediate and final products were characterized by SEC, 1H NMR, UV-VIS spectroscopy and DSC.

  3. Controlled Growth of Well-Defined Conjugated Polymers from the Surfaces of Multiwalled Carbon Nanotubes: Photoresponse Enhancement via Charge Separation.

    Science.gov (United States)

    Hou, Wenpeng; Zhao, Ning-Jiu; Meng, Dongli; Tang, Jing; Zeng, Yi; Wu, Yu; Weng, Yangziwan; Cheng, Chungui; Xu, Xiulai; Li, Yi; Zhang, Jian-Ping; Huang, Yong; Bielawski, Christopher W; Geng, Jianxin

    2016-05-24

    The installation of heterojunctions on the surfaces of carbon nanotubes (CNTs) is an effective method for promoting the charge separation processes needed for CNT-based electronics and optoelectronics applications. Conjugated polymers are proven state-of-the-art candidates for modifying the surfaces of CNTs. However, all previous attempts to incorporate conjugated polymers to CNTs resulted in unordered interfaces. Herein we show that well-defined chains of regioregular poly(3-hexylthiophene) (P3HT) were successfully grown from the surfaces of multiwalled CNTs (MWNTs) using surface-initiated Kumada catalyst-transfer polycondensation. The polymerization was found to proceed in a controlled manner as chains of tunable lengths were prepared through variation of the initial monomer-to-initiator ratio. Moreover, it was determined that large-diameter MWNTs afforded highly ordered P3HT aggregates, which exhibited a markedly bathochromically shifted optical absorption due to a high grafting density induced planarization of the polymer chains. Using ultrafast spectroscopy, the heterojunctions formed between the MWNTs and P3HT were shown to effectively overcome the binding energy of excitons, leading to photoinduced electron transfer from P3HT to MWNTs. Finally, when used as prototype devices, the individual MWNT-g-P3HT core-shell structures exhibited excellent photoresponses under a low illumination density.

  4. Well-defined nanostructured surface-imprinted polymers for highly selective magnetic separation of fluoroquinolones in human urine.

    Science.gov (United States)

    He, Yonghuan; Huang, Yanyan; Jin, Yulong; Liu, Xiangjun; Liu, Guoquan; Zhao, Rui

    2014-06-25

    The construction of molecularly imprinted polymers on magnetic nanoparticles gives access to smart materials with dual functions of target recognition and magnetic separation. In this study, the superparamagnetic surface-molecularly imprinted nanoparticles were prepared via surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization using ofloxacin (OFX) as template for the separation of fluoroquinolones (FQs). Benefiting from the living/controlled nature of RAFT reaction, distinct core-shell structure was successfully constructed. The highly uniform nanoscale MIP layer was homogeneously grafted on the surface of RAFT agent TTCA modified Fe3O4@SiO2 nanoparticles, which favors the fast mass transfer and rapid binding kinetics. The target binding assays demonstrate the desirable adsorption capacity and imprinting efficiency of Fe3O4@MIP. High selectivity of Fe3O4@MIP toward FQs (ofloxacin, pefloxacin, enrofloxacin, norfloxacin, and gatifloxacin) was exhibited by competitive binding assay. The Fe3O4@MIP nanoparticles were successfully applied for the direct enrichment of five FQs from human urine. The spiked human urine samples were determined and the recoveries ranging from 83.1 to 103.1% were obtained with RSD of 0.8-8.2% (n = 3). This work provides a versatile approach for the fabrication of well-defined MIP on nanomaterials for the analysis of complicated biosystems.

  5. Well-defined triblock copolymers of polyethylene with polycaprolactone or polystyrene using a novel difunctional polyhomologation initiator

    KAUST Repository

    Hadjichristidis, Nikolaos

    2017-08-04

    α,ω-Dihydroxy polyethylene was synthesized by polyhomologation of dimethylsulfoxonium methylide with 9-thexyl-9-BBN (9-BNN: 9-Borabicyclo[3.3.1]nonane), a novel difunctional initiator produced from 9-BBN and 2,3-dimethylbut-2-ene, with two active and one blocked sites, followed by hydrolysis/oxidation. The terminal hydroxy groups were either used directly as initiators, in the presence of 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2λ5,4λ5-catenadi(phosphazene) (t-BuP2), for the ring opening polymerization of ɛ-caprolactone to afford polycaprolactone-b-polyethylene-b-polycaprolactone (PCL-b-PE-b-PCL) or after transformation to atom transfer radical polymerization initiating sites, for the polymerization of styrene to produce polystyrene-b-polyethylene-b-polystyrene (PSt-b-PE-b-PSt) triblock copolymers. Molecular characterization by 11B, 13C and 1H NMR as well as FTIR, and high temperature GPC (HT-GPC) confirmed the well-defined nature of the synthesized new difunctional initiator and triblock copolymers. Differential scanning calorimetry was used to determine the melting points of PE and PCL.

  6. A Well-Defined Readily Releasable Pool with Fixed Capacity for Storing Vesicles at Calyx of Held

    Science.gov (United States)

    Mahfooz, Kashif; Singh, Mahendra; Renden, Robert; Wesseling, John F.

    2016-01-01

    The readily releasable pool (RRP) of vesicles is a core concept in studies of presynaptic function. However, operating principles lack consensus definition and the utility for quantitative analysis has been questioned. Here we confirm that RRPs at calyces of Held from 14 to 21 day old mice have a fixed capacity for storing vesicles that is not modulated by Ca2+. Discrepancies with previous studies are explained by a dynamic flow-through pool, established during heavy use, containing vesicles that are released with low probability despite being immediately releasable. Quantitative analysis ruled out a posteriori explanations for the vesicles with low release probability, such as Ca2+-channel inactivation, and established unexpected boundary conditions for remaining alternatives. Vesicles in the flow-through pool could be incompletely primed, in which case the full sequence of priming steps downstream of recruitment to the RRP would have an average unitary rate of at least 9/s during heavy use. Alternatively, vesicles with low and high release probability could be recruited to distinct types of release sites; in this case the timing of recruitment would be similar at the two types, and the downstream transition from recruited to fully primed would be much faster. In either case, further analysis showed that activity accelerates the upstream step where vesicles are initially recruited to the RRP. Overall, our results show that the RRP can be well defined in the mathematical sense, and support the concept that the defining mechanism is a stable group of autonomous release sites. PMID:27035349

  7. Enzymatically fabricated and degradable microcapsules for production of multicellular spheroids with well-defined diameters of less than 150 microm.

    Science.gov (United States)

    Sakai, Shinji; Ito, Sho; Ogushi, Yuko; Hashimoto, Ichiro; Hosoda, Natsuko; Sawae, Yoshinori; Kawakami, Koei

    2009-10-01

    Microcapsules with a single, spherical hollow core less than 150 microm in diameter were developed to obtain multicellular spheroids with well-defined sizes of less than 150 microm in diameter. An aqueous solution of phenolic hydroxyl derivative of carboxymethylcellulose (CMC-Ph) containing human hepatoma cell line (HepG2) cells and horse radish peroxidase (HRP) was injected into a coflowing stream of liquid paraffin, containing H(2)O(2), resulting in cell-enclosing CMC-Ph microparticles, 135 microm in diameter, via a peroxidase-catalyzed crosslinking reaction. The CMC-Ph microparticles were then coated with a phenolic hydroxyl derivative of alginate (Alg-Ph) gel membrane several dozen micrometers in thickness, crosslinked via the same enzymatic reaction process, followed by further crosslinking between the carboxyl groups of alginate by Sr(2+). A hollow core structure was achieved by immersing the resultant microcapsules in a medium containing cellulase, which degrades the enclosed CMC-Ph microparticles. The HepG2 cells in the microcapsules then grew and completely filled the hollow core. Multicellular spheroids the same size as the CMC-Ph microparticles, with living cells at their outer surface, were collected within 1 min by soaking them in a medium containing alginate lyase to degrade the Alg-Ph gel microcapsule membrane.

  8. Drug Cocktail Optimization in Chemotherapy of Cancer

    Science.gov (United States)

    Preissner, Saskia; Dunkel, Mathias; Hoffmann, Michael F.; Preissner, Sarah C.; Genov, Nikolai; Rong, Wen Wei; Preissner, Robert; Seeger, Karlheinz

    2012-01-01

    Background In general, drug metabolism has to be considered to avoid adverse effects and ineffective therapy. In particular, chemotherapeutic drug cocktails strain drug metabolizing enzymes especially the cytochrome P450 family (CYP). Furthermore, a number of important chemotherapeutic drugs such as cyclophosphamide, ifosfamide, tamoxifen or procarbazine are administered as prodrugs and have to be activated by CYP. Therefore, the genetic variability of these enzymes should be taken into account to design appropriate therapeutic regimens to avoid inadequate drug administration, toxicity and inefficiency. Objective The aim of this work was to find drug interactions and to avoid side effects or ineffective therapy in chemotherapy. Data sources and methods Information on drug administration in the therapy of leukemia and their drug metabolism was collected from scientific literature and various web resources. We carried out an automated textmining approach. Abstracts of PubMed were filtered for relevant articles using specific keywords. Abstracts were automatically screened for antineoplastic drugs and their synonyms in combination with a set of human CYPs in title or abstract. Results We present a comprehensive analysis of over 100 common cancer treatment regimens regarding drug-drug interactions and present alternatives avoiding CYP overload. Typical concomitant medication, e.g. antiemetics or antibiotics is a preferred subject to improvement. A webtool, which allows drug cocktail optimization was developed and is publicly available on http://bioinformatics.charite.de/chemotherapy. PMID:23236419

  9. Drug cocktail optimization in chemotherapy of cancer.

    Directory of Open Access Journals (Sweden)

    Saskia Preissner

    Full Text Available BACKGROUND: In general, drug metabolism has to be considered to avoid adverse effects and ineffective therapy. In particular, chemotherapeutic drug cocktails strain drug metabolizing enzymes especially the cytochrome P450 family (CYP. Furthermore, a number of important chemotherapeutic drugs such as cyclophosphamide, ifosfamide, tamoxifen or procarbazine are administered as prodrugs and have to be activated by CYP. Therefore, the genetic variability of these enzymes should be taken into account to design appropriate therapeutic regimens to avoid inadequate drug administration, toxicity and inefficiency. OBJECTIVE: The aim of this work was to find drug interactions and to avoid side effects or ineffective therapy in chemotherapy. DATA SOURCES AND METHODS: Information on drug administration in the therapy of leukemia and their drug metabolism was collected from scientific literature and various web resources. We carried out an automated textmining approach. Abstracts of PubMed were filtered for relevant articles using specific keywords. Abstracts were automatically screened for antineoplastic drugs and their synonyms in combination with a set of human CYPs in title or abstract. RESULTS: We present a comprehensive analysis of over 100 common cancer treatment regimens regarding drug-drug interactions and present alternatives avoiding CYP overload. Typical concomitant medication, e.g. antiemetics or antibiotics is a preferred subject to improvement. A webtool, which allows drug cocktail optimization was developed and is publicly available on http://bioinformatics.charite.de/chemotherapy.

  10. Cocktail of Theileria equi antigens for detecting infection in equines

    Directory of Open Access Journals (Sweden)

    Shimaa Abd El-Salam El-Sayed

    2015-12-01

    Conclusions: The ELISA technique using a cocktail formula of EMA-2 + Te 82 offers a practical and sensitive diagnostic tool for diagnosing T. equi infection in horses and using of this promising cocktail formula will be applicable for epidemiological surveys and will help control the infection in horses.

  11. Isolation and in vitro evaluation of bacteriophages against MDR-bacterial isolates from septic wound infections.

    Science.gov (United States)

    Pallavali, Roja Rani; Degati, Vijaya Lakshmi; Lomada, Dakshayani; Reddy, Madhava C; Durbaka, Vijaya Raghava Prasad

    2017-01-01

    Multi-drug resistance has become a major problem for the treatment of pathogenic bacterial infections. The use of bacteriophages is an attractive approach to overcome the problem of drug resistance in several pathogens that cause fatal diseases. Our study aimed to isolate multi drug resistant bacteria from patients with septic wounds and then isolate and apply bacteriophages in vitro as alternative therapeutic agents. Pus samples were aseptically collected from Rajiv Gandhi Institute of Medical Science (RIMS), Kadapa, A.P., and samples were analyzed by gram staining, evaluating morphological characteristics, and biochemical methods. MDR-bacterial strains were collected using the Kirby-Bauer disk diffusion method against a variety of antibiotics. Bacteriophages were collected and tested in vitro for lytic activity against MDR-bacterial isolates. Analysis of the pus swab samples revealed that the most of the isolates detected had Pseudomonas aeruginosa as the predominant bacterium, followed by Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli. Our results suggested that gram-negative bacteria were more predominant than gram-positive bacteria in septic wounds; most of these isolates were resistant to ampicillin, amoxicillin, penicillin, vancomycin and tetracycline. All the gram-positive isolates (100%) were multi-drug resistant, whereas 86% of the gram-negative isolates had a drug resistant nature. Further bacteriophages isolated from sewage demonstrated perfect lytic activity against the multi-drug resistant bacteria causing septic wounds. In vitro analysis of the isolated bacteriophages demonstrated perfect lysis against the corresponding MDR-bacteria, and these isolated phages may be promising as a first choice for prophylaxis against wound sepsis, Moreover, phage therapy does not enhance multi-drug resistance in bacteria and could work simultaneously on a wide variety of MDR-bacteria when used in a bacteriophage cocktail. Hence, our results suggest

  12. Well-Defined Bilayered Molecular Cobrushes with Internal Polyethylene Blocks and ω-Hydroxyl-Functionalized Polyethylene Homobrushes

    KAUST Repository

    Zhang, Hefeng

    2016-02-15

    Novel well-defined bilayered molecular cobrushes with internal polyethylene blocks, P(PEcore-b-PScorona) (PE: polyethylene; PS: polystyrene), and ω-hydroxyl-functionalized polyethylene homobrushes, P(PE-OH), were synthesized through the macromonomer strategy. Two main steps were involved in the synthesis of the P(PEcore-b-PScorona) bilayered cobrushes: (i) formation of norbornyl-terminated macromonomer (Nor-PE-b-PS) by esterification of PS-b-PE-OH (combination of anionic polymerization, hydroboration, and polyhomologation) with 5-norbornene-2-carboxylic acid and (ii) ring-opening metathesis polymerization (ROMP) of Nor-PE-b-PS. The synthesis of P(PE-OH) was achieved by (i) hydroboration of tert-butyldimethylsilyl-protected allyl alcohol, followed by polyhomologation of dimethylsulfoxoniun methylide with the formed tri[3-(tert-butyldimethylsilyloxyl)propyl]borane initiator, oxidation/hydrolysis, and esterification of the TBDMS-O-PE-OH with 5-norbornene-2-carboxylic acid to afford the macromonomer TBDMS-O-PE-Nor, and (ii) ROMP of TBDMS-O-PE-Nor, followed by deprotection. Nuclear magnetic resonance spectroscopy (1H and 13C NMR) and high temperature gel permeation chromatography (HT-GPC) were used to characterize all macromonomers/molecular brushes and differential scanning calorimetry (DSC) to study the thermal properties. The molecular brush P(PE-b-PS) showed lower melting point (Tm) and better solubility in toluene than the corresponding macromonomer PS-b-PE-Nor. In the case of homobrushes, the thermal properties were strongly affected by the presence of the PE end-groups. © 2016 American Chemical Society.

  13. Well-Defined Nanostructured, Single-Crystalline TiO2 Electron Transport Layer for Efficient Planar Perovskite Solar Cells.

    Science.gov (United States)

    Choi, Jongmin; Song, Seulki; Hörantner, Maximilian T; Snaith, Henry J; Park, Taiho

    2016-06-28

    An electron transporting layer (ETL) plays an important role in extracting electrons from a perovskite layer and blocking recombination between electrons in the fluorine-doped tin oxide (FTO) and holes in the perovskite layers, especially in planar perovskite solar cells. Dense TiO2 ETLs prepared by a solution-processed spin-coating method (S-TiO2) are mainly used in devices due to their ease of fabrication. Herein, we found that fatal morphological defects at the S-TiO2 interface due to a rough FTO surface, including an irregular film thickness, discontinuous areas, and poor physical contact between the S-TiO2 and the FTO layers, were inevitable and lowered the charge transport properties through the planar perovskite solar cells. The effects of the morphological defects were mitigated in this work using a TiO2 ETL produced from sputtering and anodization. This method produced a well-defined nanostructured TiO2 ETL with an excellent transmittance, single-crystalline properties, a uniform film thickness, a large effective area, and defect-free physical contact with a rough substrate that provided outstanding electron extraction and hole blocking in a planar perovskite solar cell. In planar perovskite devices, anodized TiO2 ETL (A-TiO2) increased the power conversion efficiency by 22% (from 12.5 to 15.2%), and the stabilized maximum power output efficiency increased by 44% (from 8.9 to 12.8%) compared with S-TiO2. This work highlights the importance of the ETL geometry for maximizing device performance and provides insights into achieving ideal ETL morphologies that remedy the drawbacks observed in conventional spin-coated ETLs.

  14. Adsorption of biopolymers human serum albumin and human gamma globulin to well-defined surfaces of self-assembled monolayers

    Science.gov (United States)

    Cregger, Tricia Ann

    The tenacity with which the blood proteins Human Serum Albumin (HSA) and Human Gamma Globulin (HGG) adsorb to a surface modified with a monomolecular coating varies with the packing of the alkyl chains in the coating. The adsorption of proteins onto well-defined surfaces of self-assembled monolayers (SAMs) was studied with X-ray reflectometry (XR), neutron reflectometry (NR), optical reflectometry, and total internal reflection fluorescence (TIRF). NR and XR was used to study adsorption in the absence of flow, while optical reflectometry and TIRF were used to probe the adsorption under flow conditions. In particular, competitive adsorption measurements of binary solutions of HSA, HGG and Fibrinogen (FIB) were performed with TIRE The properties of the surface were varied by altering the alkyl chains' packing density and the chain end functionality of the SAMs. The depth profiles of protein concentration near the adsorbing surface measured by NR were dependent upon the chain packing density in the case of HSA. The concentration depth profile of HGG was unaltered by varying chain packing density. Measurements performed under flow using optical reflectometry showed a different behavior: the surface excess of adsorbed HSA was relatively independent of the surface packing, while the surface excess of HGG depended on the packing density of the SAM. The tenacity with which the proteins adsorbed to different functionalized surfaces was determined by attempting to remove the protein using a strong surfactant, sodium dodecyl sulfate (SDS). Ex situ XR measurements suggested that both HSA and HGG adsorb more tenaciously to a less densely-packed monolayer, almost independent of surface functionality. Two exceptions were a less densely-packed vinyl-terminated monolayer and a less densely-packed bromine-terminated monolayer, from which HSA could not be removed at all.

  15. In situ solid-state electrochemistry of mass-selected ions at well-defined electrode-electrolyte interfaces.

    Science.gov (United States)

    Prabhakaran, Venkateshkumar; Johnson, Grant E; Wang, Bingbing; Laskin, Julia

    2016-11-22

    Molecular-level understanding of electrochemical processes occurring at electrode-electrolyte interfaces (EEIs) is key to the rational development of high-performance and sustainable electrochemical technologies. This article reports the development and application of solid-state in situ thin-film electrochemical cells to explore redox and catalytic processes occurring at well-defined EEIs generated using soft-landing (SL) of mass- and charge-selected cluster ions. In situ cells with excellent mass-transfer properties are fabricated using carefully designed nanoporous ionic liquid membranes. SL enables deposition of pure active species that are not obtainable with other techniques onto electrode surfaces with precise control over charge state, composition, and kinetic energy. SL is, therefore, demonstrated to be a unique tool for studying fundamental processes occurring at EEIs. Using an aprotic cell, the effect of charge state ([Formula: see text]) and the contribution of building blocks of Keggin polyoxometalate (POM) clusters to redox processes are characterized by populating EEIs with POM anions generated by electrospray ionization and gas-phase dissociation. Additionally, a proton-conducting cell has been developed to characterize the oxygen reduction activity of bare Pt clusters (Pt30 ∼1 nm diameter), thus demonstrating the capability of the cell for probing catalytic reactions in controlled gaseous environments. By combining the developed in situ electrochemical cell with ion SL we established a versatile method to characterize the EEI in solid-state redox systems and reactive electrochemistry at precisely defined conditions. This capability will advance the molecular-level understanding of processes occurring at EEIs that are critical to many energy-related technologies.

  16. In situ solid-state electrochemistry of mass-selected ions at well-defined electrode–electrolyte interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakaran, Venkateshkumar; Johnson, Grant E.; Wang, Bingbing; Laskin, Julia

    2016-11-07

    Molecular-level understanding of electrochemical processes occurring at electrode-electrolyte interfaces (EEI) is key to the rational development of high-performance and sustainable electrochemical technologies. This article reports the development and first application of solid-state in situ electrochemical probes to study redox and catalytic processes occurring at well-defined EEI generated using soft-landing of mass- and charge-selected cluster ions (SL). In situ electrochemical probes with excellent mass transfer properties are fabricated using carefully-designed nanoporous ionic liquid membranes. SL enables deposition of pure active species that are not obtainable with other techniques onto electrode surfaces with precise control over charge state, composition, and kinetic energy. SL is, therefore, a unique tool for studying fundamental processes occurring at EEI. For the first time using an aprotic electrochemical probe, the effect of charge state (PMo12O403-/2-) and the contribution of building blocks of Keggin polyoxometalate (POM) clusters to redox processes are characterized by populating EEI with novel POM anions generated by electrospray ionization and gas phase dissociation. Additionally, a proton conducting electrochemical probe has been developed to characterize the reactive electrochemistry (oxygen reduction activity) of bare Pt clusters (Pt40 ~1 nm diameter), thus demonstrating the capability of the probe for studying reactions in controlled gaseous environments. The newly developed in situ electrochemical probes combined with ion SL provide a versatile method to characterize the EEI in solid-state redox systems and reactive electrochemistry at precisely-defined conditions. This capability will advance molecular-level understanding of processes occurring at EEI that are critical to many energy-related technologies.

  17. [RATIONAL ASPECTS OF BACTERIOPHAGES USE].

    Science.gov (United States)

    Vakarina, A A; Kataeva, L V; Karpukhina, N F

    2015-01-01

    Analysis of existing aspects of bacteriophage use and study features of their lytic activity by using various techniques. Effect of monophages and associated bacteriophages (staphylococci, piopolyvalent and piocombined, intestiphage, pneumonia klebsiella and polyvalent klebsiella produced by "Microgen") was studied with 380 strains of Staphylococcus aureus and 279 cultures of Klebsiella pneumoniae in liquid and solid nutrient media. From patients with intestinal disorder, sensitivity was analyzed to 184 strains of Salmonella genus bacteria 18 serological variants to salmonella bacteriophages, 137 strains of Escherichia coli (lactose-negative, hemolytic), as well as some members of OKA groups (21 serovars) to coli-proteic and piopolyvalent bacteriophages. Lytic ability of the piobacteriophage against Klebsiella and Proteus genus bacteria was determined. Staphylococcus aureus was sensitive to staphylococcus bacteriophage in 71.6% of cases and to piobacteriophage--in 86.15% of cases. A 100% lytic ability of salmonella bacteriophage against Salmonella spp. was established. Sensitivity of E. coli of various serogroups to coli-proteic and piobacteriophage was 66 - 100%. Klebsiella, Proteus genus bacteria were sensitive to piobacteriophage in only 35% and 43.15% of cases, respectively. A more rational use of bacteriophages is necessary: development of a technique, evaluation of sensitivity of bacteria to bacteriophage, introduction of corrections into their production (expansion of bacteriophage spectra, determination and indication of their concentration in accompanying documents).

  18. What Can We Learn from a Metagenomic Analysis of a Georgian Bacteriophage Cocktail?

    DEFF Research Database (Denmark)

    Zschach, Henrike; Joensen, Katrine Grimstrup; Lindhard, Barbara

    2015-01-01

    Phage therapy, a practice widespread in Eastern Europe, has untapped potential in the combat against antibiotic-resistant bacterial infections. However, technology transfer to Western medicine is proving challenging. Bioinformatics analysis could help to facilitate this endeavor. In the present...

  19. Flumazenil, naloxone and the 'coma cocktail'.

    Science.gov (United States)

    Sivilotti, Marco L A

    2016-03-01

    Flumazenil and naloxone are considered to be pharmacologically ideal antidotes. By competitive binding at the molecular target receptors, they are highly specific antagonists of two important drug classes, the benzodiazepines and opioids, respectively. Both antidotes enjoy rapid onset and short duration after parenteral administration, are easily titrated and are essentially devoid of agonist effects. Yet only naloxone is widely used as a component of the 'coma cocktail', a sequence of empirical treatments to correct altered mental status, while experts discourage the use of flumazenil for such patients. This review contrasts the history, indications, published evidence and novel applications for each antidote in order to explain this disparity in the clinical use of these 'ideal' antidotes.

  20. Surface modification with well-defined biocompatible triblock copolymers Improvement of biointerfacial phenomena on a poly(dimethylsiloxane) surface.

    Science.gov (United States)

    Iwasaki, Yasuhiko; Takamiya, Mika; Iwata, Ryoko; Yusa, Shin-Ichi; Akiyoshi, Kazunari

    2007-06-15

    To improve interfacial phenomena of poly(dimethylsiloxane) (PDMS) as biomaterials, well-defined triblock copolymers were prepared as coating materials by reversible addition-fragmentation chain transfer (RAFT) controlled polymerization. Hydroxy-terminated poly(vinylmethylsiloxane-co-dimethylsiloxane) (HO-PV(l)D(m)MS-OH) was synthesized by ring-opening polymerization. The copolymerization ratio of vinylmethylsiloxane to dimethylsiloxane was 1/9. The molecular weight of HO-PV(l)D(m)MS-OH ranged from (1.43 to 4.44)x10(4), and their molecular weight distribution (M(w)/M(n)) as determined by size-exclusion chromatography equipped with multiangle laser light scattering (SEC-MALS) was 1.16. 4-Cyanopentanoic acid dithiobenzoate was reacted with HO-PV(l)D(m)MS-OH to obtain macromolecular chain transfer agents (macro-CTA). 2-Methacryloyloxyethyl phosphorylcholine (MPC) was polymerized with macro-CTAs. The gel-permeation chromatography (GPC) chart of synthesized polymers was a single peak and M(w)/M(n) was relatively narrow (1.3-1.6). Then the poly(MPC) (PMPC)-PV(l)D(m)MS-PMPC triblock copolymers were synthesized. The molecular weight of PMPC in a triblock copolymer was easily controllable by changing the polymerization time or the composition of the macro-CTA to a monomer in the feed. The synthesized block copolymers were slightly soluble in water and extremely soluble in ethanol and 2-propanol. Surface modification was performed via hydrosilylation. The block copolymer was coated on the PDMS film whose surface was pretreated with poly(hydromethylsiloxane). The surface wettability and lubrication of the PDMS film were effectively improved by immobilization with the block copolymers. In addition, the number of adherent platelets from human platelet-rich plasma (PRP) was dramatically reduced by surface modification. Particularly, the triblock copolymer having a high composition ratio of MPC units to silicone units was effective in improving the surface properties of PDMS. By

  1. Bacteriophages of Yersinia pestis.

    Science.gov (United States)

    Zhao, Xiangna; Skurnik, Mikael

    2016-01-01

    Bacteriophage play many varied roles in microbial ecology and evolution. This chapter collates a vast body of knowledge and expertise on Yersinia pestis phages, including the history of their isolation and classical methods for their isolation and identification. The genomic diversity of Y. pestis phage and bacteriophage islands in the Y. pestis genome are also discussed because all phage research represents a branch of genetics. In addition, our knowledge of the receptors that are recognized by Y. pestis phage, advances in phage therapy for Y. pestis infections, the application of phage in the detection of Y. pestis, and clustered regularly interspaced short palindromic repeats (CRISPRs) sequences of Y. pestis from prophage DNA are all reviewed here.

  2. Impact of a Single Phage and a Phage Cocktail Application in Broilers on Reduction of Campylobacter jejuni and Development of Resistance

    Science.gov (United States)

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

    2013-01-01

    Campylobacteriosis is currently the most frequent foodborne zoonosis in many countries. One main source is poultry. The aim of this study was to enhance the knowledge about the potential of bacteriophages in reducing colonization of broilers with Campylobacter , as there are only a few in vivo studies published. Commercial broilers were inoculated with 104 CFU/bird of a Campylobacter jejuni field strain. Groups of 88 birds each were subsequently treated with a single phage or a four-phage cocktail (107 PFU/bird in CaCO3 buffered SM-Buffer). Control birds received the solvent only. Afterwards, subgroups of eleven birds each were examined for their loads with phages and Campylobacter on day 1, 3, 7, 14, 21, 28, 35 and 42 after phage application. The susceptibility of the Campylobacter population to phage infection was determined using ten isolates per bird. In total 4180 re-isolates were examined. The study demonstrated that the deployed phages persisted over the whole investigation period. The Campylobacter load was permanently reduced by the phage-cocktail as well as by the single phage. The reduction was significant between one and four weeks after treatment and reached a maximum of log10 2.8 CFU/g cecal contents. Phage resistance rates of initially up to 43% in the single phage treated group and 24% in the cocktail treated group later stabilized at low levels. The occurrence of phage resistance influenced but did not override the Campylobacter reducing effect. Regarding the reduction potential, the cocktail treatment had only a small advantage over the singe phage treatment directly after phage administration. However, the cocktail moderated and delayed the emergence of phage resistance. PMID:24205254

  3. Macromolecular Engineering: New Routes Towards the Synthesis of Well-??Defined Polyethers/Polyesters Co/Terpolymers with Different Architectures

    KAUST Repository

    Alamri, Haleema

    2016-05-18

    The primary objective of this research was to develop a new and efficient pathway for well-defined multicomponent homo/co/terpolymers of cyclic esters/ethers using an organocatalytic approach with an emphasis on the macromolecular engineering aspects of the overall synthesis. Macromolecular engineering (as discussed in the first chapter) of homo/copolymers refers to the specific tailoring of these materials for achieving an easy and reproducible synthesis that results in precise molecular characteristics, i.e. molecular weight and polydispersity, as well as specific structure and end?group choices. Precise control of these molecular characteristics will provide access to new materials that can be used for pre-targeted purposes such as biomedical applications. Among the most commonly used engineering materials are polyesters (biocompatible and biodegradable) and polyethers (biocompatible), either as homopolymers or when or copolymers with linear structures. The ability to create non-linear structures, for example stars, will open new horizons in the applications of these important polymeric materials. The second part of this thesis describes the synthesis of aliphatic polyesters, particularly polycaprolactone and polylactide, using a metal-free initiator/catalyst system. A phosphazene base (t?BuP2) was used as the catalyst for the ring-opening copolymerization of ?-aprolactone (??CL) and L,Lactide (LLA) at room temperature with a variety of protic initiators in different solvents. These studies provided important information for the design of a metal-free route toward the synthesis of polyester?based (bio) materials. The third part of the thesis describes a novel route for the one?pot synthesis of polyether-b polyester block copolymers with either a linear or a specific macromolecular architecture. Poly (styrene oxide)?b?poly(caprolactone)?b?poly(L,lactide) was prepared using this method with the goal of synthesizing poly(styrene oxide)-based materials since this

  4. Inactivation of Escherichia coli O157:H7 attached to spinach harvester blade using bacteriophage.

    Science.gov (United States)

    Patel, Jitendra; Sharma, Manan; Millner, Patricia; Calaway, Todd; Singh, Manpreet

    2011-04-01

    Outbreaks associated with leafy greens have focused attention on the transfer of human pathogens to these commodities during harvest with commercial equipment. Attachment of Escherichia coli O157:H7 on new or rusty spinach harvester blades immersed in spinach extract or 10% tryptic soy broth (TSB) was investigated. Bacteriophages specific for E. coli O157:H7 were evaluated to kill cells attached to blade. A cocktail of five nalidixic acid-resistant E. coli O157:H7 isolates was transferred to 25 mL of spinach extract or 10% TSB. A piece of sterilized spinach harvester blade (2×1") was placed in above spinach extract or 10% TSB and incubated at room (22 °C) or dynamic (30 °C day, 20 °C night) temperatures. E. coli O157:H7 populations attached to blade during incubation in spinach extract or 10% TSB were determined. When inoculated at 1 log CFU/mL, E. coli O157:H7 attachment to blades after 24 and 48 h incubation at dynamic temperature (6.09 and 6.37 log CFU/mL) was significantly higher than when incubated at 22 °C (4.84 and 5.68 log CFU/mL), respectively. After 48 h incubation, two blades were sprayed on each side with a cocktail of E. coli O157-specific bacteriophages before scraping the blade, and subsequent plating on Sorbitol MacConkey media-nalidixic acid. Application of bacteriophages reduced E. coli O157:H7 populations by 4.5 log CFU on blades after 2 h of phage treatment. Our study demonstrates that E. coli O157:H7 can attach to and proliferate on spinach harvester blades under static and dynamic temperature conditions, and bacteriophages are able to reduce E. coli O157:H7 populations adhered to blades.

  5. Wound healing potential of topical bacteriophage therapy on diabetic cutaneous wounds.

    Science.gov (United States)

    Mendes, João J; Leandro, Clara; Corte-Real, Sofia; Barbosa, Raquel; Cavaco-Silva, Patrícia; Melo-Cristino, José; Górski, Andrzej; Garcia, Miguel

    2013-01-01

    Chronic wounds that fail to heal are a common complication of diabetes mellitus and the most common precipitating reason for nontraumatic lower limb amputation. Unfortunately, the bacterial species that cause these infections are becoming more resistant to antibiotics, making them increasingly difficult to treat. We assessed the feasibility of combating chronic bacterial infections with a topically delivered bacteriophage cocktail in two animal models of diabetes mellitus. Microbiological, planimetric, and histological parameters were compared in debrided infected wounds with or without topical bacteriophage treatment. We determined that bacteriophage treatment effectively decreased bacterial colony counts and improved wound healing, as indicated by smaller epithelial and dermal gaps, in Staphylococcus aureus and Pseudomonas aeruginosa infections but was not as effective against Acinetobacter baumannii. Although the improvements were more significant in the rodent model than in the porcine model, our results suggest that topically administered bacteriophage treatment may be effective in resolving chronic infections, especially when applied in conjunction with wound debridement. These findings have important implications for the feasibility of using topical antimicrobial therapies to safely treat chronic infections in diabetes mellitus patients. © 2013 by the Wound Healing Society.

  6. Cocoa Fermentations Conducted with a Defined Microbial Cocktail Inoculum

    OpenAIRE

    Schwan, Rosane Freitas

    1998-01-01

    Cocoa fermentations were performed in wooden boxes under the following four experimental regimens: beans naturally fermented with wild microflora; aseptically prepared beans with no inoculum; and beans inoculated with a defined cocktail containing microorganisms at a suitable concentration either at zero time or by using phased additions at appropriate times. The cocktail used consisted of a yeast, Saccharomyces cerevisiae var. chevalieri, two lactic acid bacterial species, Lactobacillus lact...

  7. A Performance Comparison of Nine Selected Liquid Scintillation Cocktails

    Energy Technology Data Exchange (ETDEWEB)

    Verrezen, F.; Loots, H.; Hurtgen, Ch.

    2008-06-15

    In the selection of a suitable liquid scintillation (LSC) cocktail, the primary aspects taken into consideration are overall cocktail performance and specific laboratory needs. Overall performance of 9 selected, commercially available LSC cocktails was assessed by studying parameters of importance for the requirements of the Laboratory for Low Level Radioactivity Measurements of SCK-CEN: sample load capacity, sample compatibility, influence of sample load on counting efficiency, background count rate, figure of merit, quench resistance, sample stability and alpha/beta separation characteristics. The cocktails tested were EcoscintA, Insta Gel Plus, OptiPhase Hisafe3, OptiPhase Trisafe, Ready Gel, SafeScint 1:1, Ultima Gold, Ultima Gold LLT, and Ultima Gold XR. For the data acquisition a Packard TriCarb Model 1900CA and a Quantulus 1220 liquid scintillation counter is used. All samples were prepared in either 20 mL low potassium, borosilicate glass vials or 20 mL high density, polyethylene vials. The aim of this study was to determine a single cocktail that best suits all measurement requirements of the liquid scintillation laboratory at SCK-CEN for the determination of low levels of radioactivity in biological and environmental samples. As a conclusion, Optiphase HiSafe 3 was confirmed to be the optimal cocktail for the laboratory.

  8. [Possibilities of bacteriophage therapy].

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Carlota eBardina

    2016-04-01

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

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

    Science.gov (United States)

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

    2016-01-01

    terminase subunits confirms their packaging strategies and grouping to the different phage genus type. All these studies are necessary for the development and the use of an efficient cocktail with commercial applications in bacteriophage therapy against Salmonella. PMID:27148229

  12. Heavy ion cocktail beams at the 88 inch Cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Leitner, Daniela; McMahan, Margaret A.; Argento, David; Gimpel, Thomas; Guy, Aran; Morel, James; Siero, Christine; Thatcher, Ray; Lyneis, Claude M.

    2002-09-03

    Cyclotrons in combination with ECR ion sources provide the ability to accelerate ''cocktails'' of ions. A cocktail is a mixture of ions of near-identical mass-to-charge (m/q) ratio. The different ions cannot be separated by the injector mass-analyzing magnet and are tuned out of the ion source together. The cyclotron then is utilized as a mass analyzer by shifting the accelerating frequency. This concept was developed soon after the first ECR ion source became operational at the 88-Inch Cyclotron and has since become a powerful tool in the field of heavy ion radiation effects testing. Several different ''cocktails'' at various energies are available at the 88-Inch cyclotron for radiation effect testing, covering a broad range of linear energy transfer and penetration depth. Two standard heavy ion cocktails at 4.5 MeV/nucleon and 10 MeV/nucleon have been developed over the years containing ions from boron to bismuth. Recently, following requests for higher penetration depths, a 15MeV/nucleon heavy ion cocktail has been developed. Up to nine different metal and gaseous ion beams at low to very high charge states are tuned out of the ion source simultaneously and injected together into the cyclotron. It is therefore crucial to balance the ion source very carefully to provide sufficient intensities throughout the cocktail. The paper describes the set-up and tuning of the ion source for the various heavy ion cocktails.

  13. Long-Term Safety of Topical Bacteriophage Application to the Frontal Sinus Region

    Science.gov (United States)

    Drilling, Amanda J.; Ooi, Mian L.; Miljkovic, Dijana; James, Craig; Speck, Peter; Vreugde, Sarah; Clark, Jason; Wormald, Peter-John

    2017-01-01

    Background: Staphylococcus aureus biofilms contribute negatively to a number of chronic conditions, including chronic rhinosinusitis (CRS). With the inherent tolerance of biofilm-bound bacteria to antibiotics and the global problem of bacterial antibiotic resistance, the need to develop novel therapeutics is paramount. Phage therapy has previously shown promise in treating sinonasal S. aureus biofilms. Methods: This study investigates the long term (20 days) safety of topical sinonasal flushes with bacteriophage suspensions. The bacteriophage cocktail NOV012 against S. aureus selected for this work contains two highly characterized and different phages, P68 and K710. Host range was assessed against S. aureus strains isolated from CRS patients using agar spot tests. NOV012 was applied topically to the frontal sinus region of sheep, twice daily for 20 days. General sheep wellbeing, mucosal structural changes and inflammatory load were assessed to determine safety of NOV012 application. Results: NOV012 could lyse 52/61 (85%) of a panel of locally derived CRS clinical isolates. Application of NOV012 to the frontal sinuses of sheep for 20 days was found to be safe, with no observed inflammatory infiltration or tissue damage within the sinus mucosa. Conclusion: NOV012 cocktail appears safe to apply for extended periods to sheep sinuses and it could infect and lyse a wide range of S. aureus CRS clinical isolates. This indicates that phage therapy has strong potential as a treatment for chronic bacterial rhinosinusitis. PMID:28286740

  14. Bacteriophage in polar inland waters

    Science.gov (United States)

    Säwström, Christin; Lisle, John; Anesio, A.M.; Priscu, John C.; Laybourn-Parry, J.

    2008-01-01

    Bacteriophages are found wherever microbial life is present and play a significant role in aquatic ecosystems. They mediate microbial abundance, production, respiration, diversity, genetic transfer, nutrient cycling and particle size distribution. Most studies of bacteriophage ecology have been undertaken at temperate latitudes. Data on bacteriophages in polar inland waters are scant but the indications are that they play an active and dynamic role in these microbially dominated polar ecosystems. This review summarises what is presently known about polar inland bacteriophages, ranging from subglacial Antarctic lakes to glacial ecosystems in the Arctic. The review examines interactions between bacteriophages and their hosts and the abiotic and biotic variables that influence these interactions in polar inland waters. In addition, we consider the proportion of the bacteria in Arctic and Antarctic lake and glacial waters that are lysogenic and visibly infected with viruses. We assess the relevance of bacteriophages in the microbial loop in the extreme environments of Antarctic and Arctic inland waters with an emphasis on carbon cycling.

  15. Bacteriophages of methanotrophic bacteria

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-10-01

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

  16. Genetically modified bacteriophages.

    Science.gov (United States)

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

    2016-04-18

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

  17. A new approach for the preparation of well-defined Rh and Pt nanoparticles stabilized by phosphine-functionalized silica for selective hydrogenation reactions.

    Science.gov (United States)

    Llop Castelbou, J; Szeto, K C; Barakat, W; Merle, N; Godard, C; Taoufik, M; Claver, C

    2017-03-18

    In this work, a new methodology for the synthesis of well-defined metallic nanoparticles supported on silica is described. This methodology is based on the surface control provided by SOMC. The nanoparticles are formed via the organometallic approach and are catalytically active in the hydrogenation of p-xylene, 3-hexyne, 4-phenyl-2 butanone, benzaldehyde, and furfural.

  18. Functional limitations in functional somatic syndromes and well-defined medical diseases : Results from the general population cohort LifeLines

    NARCIS (Netherlands)

    Joustra, Monica L.; Janssens, Karin A.M.; Bültmann, Ute; Rosmalen, Judith G.M.

    Objective: Functional somatic syndromes (FSS), defined as physical syndromes without known underlying organic pathology, are sometimes regarded as less serious conditions than well-defined medical diseases (MD). The aims of this study were to evaluate functional limitations in FSS, and to compare

  19. A well-defined silica-supported aluminium alkyl through an unprecedented, consecutive two-step protonolysis–alkyl transfer mechanism

    KAUST Repository

    Pelletier, Jérémie

    2011-01-01

    Impregnation of [(AliBu3)(Et2O)] on partially dehydroxylated SBA-15 affords a mesoporous material bearing the well-defined single site surface aluminium species [(≡SiO)2Al(iBu)(Et 2O)]. © The Royal Society of Chemistry.

  20. A one-step co-condensation method for the synthesis of well-defined functionalized mesoporous SBA-15 using trimethallylsilanes as organosilane sources.

    Science.gov (United States)

    Han, Ye Ri; Park, Jung-Woo; Kim, Hanil; Ji, Hyejeong; Lim, Soo Hyun; Jun, Chul-Ho

    2015-12-14

    A new method for the preparation of well-defined functionalized mesoporous SBA-15 has been developed by a one-step co-condensation method using trimethallylsilanes as organosilane sources. This new method enables the incorporation of various bulky organic functional groups with long alkyl chain tethers into the mesoporous silica network.

  1. Utilization of Skills in the Care of the Patient with Common, Well-Defined Health Deviations I (NS 217): Competency-Based Course Syllabus.

    Science.gov (United States)

    Green, Elizabeth G.; Yates, Laura H.

    "Utilization of Skills in the Care of the Patient with Common, Well-Defined Health Deviations I" (NS 217) is an associate degree nursing course offered at Chattanooga State Technical Community College to help students develop new competencies necessary for the care of patients with deviations of the cardiovascular, endocrine, integumentary, and…

  2. Comparative analysis of two and three marker immunohistochemical cocktails in the diagnosis of prostata carcinoma

    DEFF Research Database (Denmark)

    Dabir, Parag Deepak; Ottosen, Peter; Hamilton-Dutoit, Stephen Jacques;

    2013-01-01

    Comparative analysis of two and three marker immunohistochemical cocktails in the diagnosis of prostata carcinoma......Comparative analysis of two and three marker immunohistochemical cocktails in the diagnosis of prostata carcinoma...

  3. Comparative analysis of two and three marker immunohistochemical cocktails in the diagnosis of prostata carcinoma

    DEFF Research Database (Denmark)

    Dabir, Parag Deepak; Ottosen, Peter; Hamilton-Dutoit, Stephen Jacques;

    2012-01-01

    Comparative analysis of two and three marker immunohistochemical cocktails in the diagnosis of prostata carcinoma......Comparative analysis of two and three marker immunohistochemical cocktails in the diagnosis of prostata carcinoma...

  4. ‘Ireland’s Largest Live Cocktail Challenge Attracts over 70 Mixologists’

    OpenAIRE

    2014-01-01

    The 2nd DIT Monin Cocktail Challenge took place on Thursday November 20th 2014, this initiative between the DIT Bar Management Studies and Monin attracted 70 mixologists. Prizes were awarded for the top non-alcohol cocktails presented and best technical performance. All cocktails were based on Monin premium syrups and purees, points were awarded for the appearance, aroma, taste and the commercial appeal of the cocktails. Mr. James Murphy (Competition Co-ordinator, DIT Lecturer, Bar Management...

  5. Electronic Effects of Aluminum Complexes in the Copolymerization of Propylene Oxide with Tricyclic Anhydrides: Access to Well-Defined, Functionalizable Aliphatic Polyesters.

    Science.gov (United States)

    Van Zee, Nathan J; Sanford, Maria J; Coates, Geoffrey W

    2016-03-02

    The synthesis of well-defined and functionalizable aliphatic polyesters remains a key challenge in the advancement of emerging drug delivery and self-assembly technologies. Herein, we investigate the factors that influence the rates of undesirable transesterification and epimerization side reactions at high conversion in the copolymerization of tricyclic anhydrides with excess propylene oxide using aluminum salen catalysts. The structure of the tricyclic anhydride, the molar ratio of the aluminum catalyst to the nucleophilic cocatalyst, and the Lewis acidity of the aluminum catalyst all influence the rates of these side reactions. Optimal catalytic activity and selectivity against these side reactions requires a careful balance of all these factors. Effective suppression of undesirable transesterification and epimerization was achieved even with sterically unhindered monomers using a fluorinated aluminum salph complex with a substoichiometric amount of a nucleophilic cocatalyst. This process can be used to synthesize well-defined block copolymers via a sequential addition strategy.

  6. Counterions control whether self-assembly leads to formation of stable and well-defined unilamellar nanotubes or nanoribbons and nanorods

    DEFF Research Database (Denmark)

    Shi, Dong; Schwall, Christian; Sfintes, George

    2014-01-01

    Self-assembly of the amphiphilic π-conjugated carbenium ion ATOTA-1(+) in aqueous solution selectively leads to discrete and highly stable nanotubes or nanoribbons and nanorods, depending on the nature of the counterion (Cl(-) vs. PF6(-), respectively). The nanotubes formed by the Cl(-) salt...... illustrate an exceptional example of a structural well-defined (29±2 nm in outer diameter) unilamellar tubular morphology featuring π-conjugated functionality and high stability and flexibility, in aqueous solution....

  7. Well-defined hydrophilic molecularly imprinted polymer microspheres for efficient molecular recognition in real biological samples by facile RAFT coupling chemistry.

    Science.gov (United States)

    Zhao, Man; Chen, Xiaojing; Zhang, Hongtao; Yan, Husheng; Zhang, Huiqi

    2014-05-12

    A facile and highly efficient new approach (namely RAFT coupling chemistry) to obtain well-defined hydrophilic molecularly imprinted polymer (MIP) microspheres with excellent specific recognition ability toward small organic analytes in the real, undiluted biological samples is described. It involves the first synthesis of "living" MIP microspheres with surface-bound vinyl and dithioester groups via RAFT precipitation polymerization (RAFTPP) and their subsequent grafting of hydrophilic polymer brushes by the simple coupling reaction of hydrophilic macro-RAFT agents (i.e., hydrophilic polymers with a dithioester end group) with vinyl groups on the "living" MIP particles in the presence of a free radical initiator. The successful grafting of hydrophilic polymer brushes onto the obtained MIP particles was confirmed by SEM, FT-IR, static contact angle and water dispersion studies, elemental analyses, and template binding experiments. Well-defined MIP particles with densely grafted hydrophilic polymer brushes (∼1.8 chains/nm(2)) of desired chemical structures and molecular weights were readily obtained, which showed significantly improved surface hydrophilicity and could thus function properly in real biological media. The origin of the high grafting densities of the polymer brushes was clarified and the general applicability of the strategy was demonstrated. In particular, the well-defined characteristics of the resulting hydrophilic MIP particles allowed the first systematic study on the effects of various structural parameters of the grafted hydrophilic polymer brushes on their water-compatibility, which is of great importance for rationally designing more advanced real biological sample-compatible MIPs.

  8. Cocktail of Theileria equi antigens for detecting infection in equines

    Institute of Scientific and Technical Information of China (English)

    Shimaa; Abd; El-Salam; El-Sayed; Mohamed; Abdo; Rizk; Mohamed; Alaa; Terkawi; Ahmed; Mousa; El; Said; El; Shirbini; El; Said; Gehad; Elsayed; Mohamed; Fouda; Naoaki; Yokoyama; Ikuo; Igarashi

    2015-01-01

    Objective:To use two diagnostic antigens belonging to the frequently associated in Theileria domain,Theileria equi(T.equi)protein 82(Te 82)and T.equi 104 k Da microneme-rhoptry antigen precursor(Te 43),to diagnose T.equi infection in horses as compared with equi merozoite antigen-2(EMA-2).Methods:In the current study,we applied a cocktail-ELISA containing two antigens(EMA-2+Te 82)to diagnose T.equi infection either in experimentally infected horses or in field infection.Results:Our findings have revealed that a cocktail formula of EMA-2+Te 82 provided a more practical and sensitive diagnostic candidate for diagnosing T.equi infection in horses as compared with Te 82 or Te 43 alone.Conclusions:The ELISA technique using a cocktail formula of EMA-2+Te 82 offers a practical and sensitive diagnostic tool for diagnosing T.equi infection in horses and using of this promising cocktail formula will be applicable for epidemiological surveys and will help control the infection in horses.

  9. Cocktail of Theileria equi antigens for detecting infection in equines

    Institute of Scientific and Technical Information of China (English)

    Shimaa Abd El-Salam El-Sayed; Mohamed Abdo Rizk; Mohamed Alaa Terkawi; Ahmed Mousa; El Said El Shirbini El Said; Gehad Elsayed; Mohamed Fouda; Naoaki Yokoyama; Ikuo Igarashi

    2015-01-01

    Objective: To use two diagnostic antigens belonging to the frequently associated in Theileria domain, Theileria equi (T. equi) protein 82 (Te 82) and T. equi 104 kDa microneme-rhoptry antigen precursor (Te 43), to diagnose T. equi infection in horses as compared with equi merozoite antigen-2 (EMA-2). Methods: In the current study, we applied a cocktail-ELISA containing two antigens (EMA-2+Te 82) to diagnose T. equi infection either in experimentally infected horses or in field infection. Results: Our findings have revealed that a cocktail formula of EMA-2+Te 82 provided a more practical and sensitive diagnostic candidate for diagnosing T. equi infection in horses as compared with Te 82 or Te 43 alone. Conclusions: The ELISA technique using a cocktail formula of EMA-2+Te 82 offers a practical and sensitive diagnostic tool for diagnosing T. equi infection in horses and using of this promising cocktail formula will be applicable for epidemiological surveys and will help control the infection in horses.

  10. Training to Increase Safe Tray Carrying among Cocktail Servers

    Science.gov (United States)

    Scherrer, Megan D.; Wilder, David A.

    2008-01-01

    We evaluated the effects of training on proper carrying techniques among 3 cocktail servers to increase safe tray carrying on the job and reduce participants' risk of developing musculoskeletal disorders. As participants delivered drinks to their tables, their finger, arm, and neck positions were observed and recorded. Each participant received…

  11. Edge-clique graphs of cocktail parties have unbounded rankwidth

    CERN Document Server

    Chang, Maw-Shang; Liu, Ching-Hao

    2012-01-01

    In an attempt to find a polynomial-time algorithm for the edge-clique cover problem on cographs we tried to prove that the edge-clique graphs of cographs have bounded rankwidth. However, this is not the case. In this note we show that the edge-clique graphs of cocktail party graphs have unbounded rankwidth.

  12. From Contests to Cocktail Parties: Strategies for Impromptu Speaking.

    Science.gov (United States)

    Katchen, Johanna E.

    Classroom techniques are offered for teaching students how to present a spontaneous (impromptu) speech in a second language, such as for use at a job interview or cocktail party. It is first suggested that such classroom activity be graded minimally to help lower students' level of apprehension. Then strategies for approaching impromptu speech…

  13. Virulence reduction in Bacteriophage resistant bacteria

    Directory of Open Access Journals (Sweden)

    Marcela eLeón

    2015-04-01

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

  14. Bacteriophage endolysins as novel antimicrobials

    Science.gov (United States)

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

  15. Bacteriophage: from exploration to exploitation

    NARCIS (Netherlands)

    Nobrega, Franklin L.

    2017-01-01

    Over the past decades, bacteriophage research has revealed the abundance of phages in nature, their morphological and genomic diversity, their influence in the regulation of microbial balance in the ecosystem and their impact on the evolution of microbial diversity. Since the 1950s, phages have also

  16. Bacteriophage therapy in animal production

    Science.gov (United States)

    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...

  17. Metagenomic analysis of dairy bacteriophages

    DEFF Research Database (Denmark)

    Muhammed, Musemma Kedir; Kot, Witold Piotr; Neve, Horst

    2017-01-01

    Despite their huge potential for characterizing the biodiversity of phages, metagenomic studies are currently not available for dairy bacteriophages, partly due to the lack of a standard procedure for phage extraction. We optimized an extraction method that allows to remove the bulk protein from...

  18. Bacteriophage: from exploration to exploitation

    NARCIS (Netherlands)

    Nobrega, Franklin L.

    2017-01-01

    Over the past decades, bacteriophage research has revealed the abundance of phages in nature, their morphological and genomic diversity, their influence in the regulation of microbial balance in the ecosystem and their impact on the evolution of microbial diversity. Since the 1950s, phages have also

  19. Nanoscale bacteriophage biosensors beyond phage display

    Directory of Open Access Journals (Sweden)

    Lee JW

    2013-10-01

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

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

    Science.gov (United States)

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

    2016-05-26

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

  1. Unearthing a Well-Defined Highly Active Bimetallic W/Ti Precatalyst Anchored on a Single Silica Surface for Metathesis of Propane

    KAUST Repository

    Samantaray, Manoja

    2017-02-10

    Two compatible organometallic complexes, W(Me)(6) (1) and TiNp4 (2), were successively anchored on a highly dehydroxylated single silica support (SiO2-700) to synthesize the well-defined bimetallic precatalyst [(equivalent to Si-O-)W(Me)(5)(equivalent to Si-O-)Ti(Np)(3)] (4). Precatalyst 4 was characterized at the molecular level using advanced surface organometallic chemistry (SOMC) characterization techniques. The strong autocorrelation observed between methyl of W and Ti in H-1-H-1 multiple-quantum NMR spectra demonstrates that W and Ti species are in close proximity to each other. The bimetallic precatalyst 4, with a turnover number (TON) of 9784, proved to be significantly more efficient than the silica-supported monometallic catalyst [(equivalent to Si-O-)W(Me)(5)] (3), with a TON of 98, for propane metathesis at 150 degrees C in a flow reactor. The dramatic improvement in the activity signifies the cooperativity between Ti and W and indicates that the key step of alkane metathesis (C-H bond activation followed by beta-H elimination) occurs on Ti, followed by olefin metathesis, which occurs on W. We have demonstrated the influence and importance of proximity of Ti to W for achieving such a significantly high activity. This is the first report demonstrating the considerably high activity (TON = 9784) in propane metathesis at moderate temperature (150 degrees C) using a well-defined bimetallic system prepared via the SOMC approach.

  2. Tailor-made starch-based conjugates containing well-defined poly(vinyl acetate and its derivative poly(vinyl alcohol

    Directory of Open Access Journals (Sweden)

    2011-06-01

    Full Text Available Reversible addition-fragmentation chain transfer (RAFT polymerization was adopted to synthesize starch-based conjugates that possessed controllable architecture and properties. Starch-based xanthate agent was prepared and applied as chain transfer agent to conduct the living/controlled polymerization (LCP of vinyl acetate, which generated tailor-made conjugates of starch and well-defined poly(vinyl acetate (SVAc. The relevant derivatives, conjugates of starch and chain length-controlled poly(vinyl alcohol (SVA, were obtained subsequently. Various characterizations such as Fourier transform infrared spectra (FTIR, ultraviolet-visible spectroscopy (UV, proton nuclear magnetic resonance (1H NMR, gel permeation chromatography (GPC, X-ray diffraction (XRD, Thermogravimetric analysis (TGA, and dynamic mechanical thermal analysis (DMTA were performed to examine the structure of intermediates and the starch-based conjugates. Static contact angle measurements revealed that the hydrophilic character of starch-based conjugates was tunable. Well-defined SVAc was amphiphilic and it was able to self-assemble into size controllable micelles, which was verified by contact angles, transmission electron microscopy (TEM and dynamic light scattering (DLS tests. SVA exhibited much higher capability to form physically cross-linked hydrogel than starch did. Both the characteristic of SVAc and SVA were chain length-dependent.

  3. Physiological and Molecular Characterization of Salmonella Bacteriophages Previously Used in Phage Therapy.

    Science.gov (United States)

    Zhang, J; Hong, Y; Fealey, M; Singh, A; Walton, K; Martin, C; Harman, N J; Mahlie, J; Ebner, P D

    2015-12-01

    The use of bacteriophages as biocontrol agents to control Salmonella in food production has gained popularity over the last two decades. Previously, our laboratory demonstrated that bacteriophages can be direct fed to limit Salmonella colonization and transmission in pigs. Here, we characterized the bacteriophages in our treatment cocktail in terms of lytic spectrum, growth kinetics, survivability under various conditions, and genomic sequencing. PCR-based fingerprinting indicated that 9 of the 10 phages, while related, were distinct isolates. Single-step growth kinetics analysis determined that the eclipse periods, latent periods, and burst sizes averaged 21.5 min, 31.5 min, and 43.3 particles, respectively. The viability of the phages was measured after exposure to various pH ranges, temperatures, digestive enzymes, UV light, and chlorinated water. Temperatures greater than 87.5°C, pH of phages. Only select bacteriophages, however, were affected by incubation at temperatures of ≤75.0°C or pH of 4.0 to 10.0. Genomic sequencing of the phage with the broadest spectrum in the collection (effectively lysed all four Salmonella serovars tested), vB_SalM_SJ2, revealed it to belong to the Viunalikevirus genus of the Myoviridae family. Of the 197 predicted open reading frames, no toxin-associated, lysogenic, Salmonella virulence, or antimicrobial resistance genes were identified. Taken together, these data indicate that phages, as biologicals, may require some manner of protection (e.g., microencapsulation) to remain viable under various physiological and manufacturing conditions. In addition, based on its ability to effectively lyse diverse Salmonella serovars, phage vB_SalM-SJ2 could be further developed as an important biocontrol agent in various aspects of food production when the exact serovar or strain of contaminating Salmonella is not yet known.

  4. [Some immunological changes in children with bacterial infections treated with bacteriophages].

    Science.gov (United States)

    Pagava, K I; Metskhvarishvili, G D; Gachechiladze, K K; Korinteli, I A; Khoĭle, N; Dzuliashvili, M G

    2012-11-01

    The aim of the study was to reveal the possible immunological changes in children with bacterial infections treated with commercial bacteriophage preparations administered per os. In case of medical indications (for treatment or diagnostic) blood sampling was carried out. In serum the antibodies against bacteriophage preparations - phage cocktail components (phages against Staphylococcus, Streptococcus, Proteus vulgaris, Escherichia coli, Pseudomonas aeruginosa) were investigated. The neutralisation reaction was used. There were processed samples from 65 children with following diagnoses: sepsis, bacterial pneumonia, urinary tract infection, bacterial infections of upper respiratory ways, bacterial diarrhea. In samples taken in the first days of treatment antibodies were revealed in infants up to one month (I group) in 0/29 cases - 0%, in infants aged from one month till one year (II group)- 1/25 - 4.0%, in children aged from 1 till 15 years (III group) - 3/9 - 33.3%; data after 14-20 days from the beginning of treatment - I group - 0/9 - 0%, II group - 4/15 - 26.7%, III group - 5/5 - 100%; data after 30-60 days from the beginning of the treatment - I group - 1/5 - 20.0%, II group - 6/10 - 60.0%, III group - 3/3 - 100%. Bacteriophages neitralisation degree varied between 50,7% and 97.3%. Any regularity regarding different components of used phage preparations was not established. In case of inclusion of commercial phage preparations administered per os in the treatment of bacterial infections in children, the anti-phage neutralizing antibodies are produced by the macroorganism. This fact limits the duration of phage therapy and its usage in the treatment of future bacterial infections in treated patients. Production of anti-phage antibodies in young infants is substantially less expressed and this indicates to purposefulness and presumably higher efficacy of bacteriophage therapy in this age period.

  5. Long-term changes in bone mass after partial gastrectomy in a well-defined population and its relation to tobacco and alcohol consumption

    DEFF Research Database (Denmark)

    Krogsgaard, M R; Frølich, A; Lund, B;

    1995-01-01

    We studied the long-term effect of partial gastrectomy on bone metabolism in a well defined population of gastrectomized patients compared to an age- and sex-matched group with unoperated peptic ulcers (controls). We selected 61 individuals between 61 and 70 years old at the time of investigation...... and insignificantly lower in the other operated groups. In men, ionized and total calcium was reduced, and 24-hour excretion of hydroxyproline in the urine as increased (p ... and unoperated patients in serum levels of alkaline phosphatases, iPTH, calcitriol, or the 24-hour urine calcium/creatinine excretion, even though there was a trend toward lower 24-hour urine calcium/creatinine ratio and increased levels in iPTH in the operated groups. There was no correlation between the daily...

  6. Membranes with well-defined ions transport channels fabricated via solvent-responsive layer-by-layer assembly method for vanadium flow battery.

    Science.gov (United States)

    Xu, Wanxing; Li, Xianfeng; Cao, Jingyu; Zhang, Hongzhang; Zhang, Huamin

    2014-02-06

    In this work we presented a general strategy for the fabrication of membranes with well-defined ions transport channels through solvent-responsive layer-by-layer assembly (SR-LBL). Multilayered poly (diallyldimethylammonium chloride) (PDDA) and poly (acrylic acid) (PAA) complexes were first introduced on the inner pore wall and the surface of sulfonated poly (ether ether ketone)/poly (ether sulfone) (PES/SPEEK) nanofiltration membranes to form ions transport channels with tuned radius. This type of membranes are highly efficient for the separators of batteries especially vanadium flow batteries (VFBs): the VFBs assembled with prepared membranes exhibit an outstanding performance in a wide current density range, which is much higher than that assembled with commercial Nafion 115 membranes. This idea could inspire the development of membranes for other flow battery systems, as well as create further progress in similar areas such as fuel cells, electro-dialysis, chlor-alkali cells, water electrolysis and so on.

  7. Synthesis and Biological Evaluation of Well-Defined Poly(propylene fumarate) Oligomers and Their Use in 3D Printed Scaffolds.

    Science.gov (United States)

    Luo, Yuanyuan; Dolder, Courtney K; Walker, Jason M; Mishra, Ruchi; Dean, David; Becker, Matthew L

    2016-02-08

    A ring opening polymerization method for synthesizing oligomeric poly(propylene fumarate) (PPF) provides a rapid, and scalable method of synthesizing PPF with well-defined molecular mass, molecular mass distribution (Đm), and viscosity properties suitable for 3D printing. These properties will also reduce the amount of solvent necessary to ensure sufficient flow of material during 3D printing. MALDI mass spectrometry precisely shows the end group fidelity, and size exclusion chromatography (SEC) demonstrates narrow mass distributions (3000 Da). The corresponding intrinsic viscosities range from 0.0288 ± 0.0009 dL/g to 0.0780 ± 0.0022 dL/g. The oligomers were printed into scaffolds via established photochemical methods and standardized ISO 10993-5 testing shows that the 3D printed materials are nontoxic to both L929 mouse fibroblasts and human mesenchymal stem cells.

  8. Well-defined silica supported bipodal molybdenum oxo alkyl complexes: a model of the active sites of industrial olefin metathesis catalysts

    KAUST Repository

    Merle, Nicolas

    2017-09-25

    A well-defined, silica-supported molybdenum oxo alkyl species, ([triple bond, length as m-dash]SiO-)2Mo([double bond, length as m-dash]O)(CH2tBu)2, was prepared by the selective grafting of Mo([double bond, length as m-dash]O)(CH2tBu)3Cl onto a silica partially dehydroxylated at 200 °C using a rigorous surface organometallic chemistry approach. The immobilized bipodal surface species, partly resembling the active species of industrial MoO3/SiO2 olefin metathesis catalysts, exhibited excellent functional group tolerance in conjunction with its high activity in homocoupling, self and ring closing olefin metathesis.

  9. Synthesis of bis-peptides attached on poly[n]norbornene molecular scaffolds with well-defined relative positions and distances.

    Science.gov (United States)

    Shang, Muhong; Warrener, Ronald N; Butler, Douglas N; Murata, Yasujiro; Margetić, Davor

    2011-05-01

    This article describes novel synthetic approaches to polynorbornene molecular scaffolds substituted with peptides at various, well-defined positions. A library of norbornene building blocks with attached peptides was prepared. Alkene cyclobutane epoxide (ACE) coupling method was used as a key step reaction for the connection of two norbornene building blocks into bis-peptide scaffolds. Photodimerization of cyclobutene diesters offers an alternative route to polynorbornene bis-peptides. Pyrrolo-peptides were used for preparation of peptide-substituted 7-aza norbornenes. Asymmetrical bis-peptide scaffolds were prepared by ACE coupling of peptide-norbornane epoxide with another norbornene-peptide block. Chemical elaboration of bridgehead dimethyl esters of ACE products or epoxide ACE reagents was also used for peptide attachment.

  10. Well-Defined Degradable Cationic Polylactide as Nanocarrier for the Delivery of siRNA to Silence Angiogenesis in Prostate Cancer

    Science.gov (United States)

    Chen, Chih-Kuang; Law, Wing-Cheung; Aalinkeel, Ravikumar; Nair, Bindukumar; Kopwitthaya, Atcha; Mahajan, Supriya D.; Reynolds, Jessica L.; Zou, Jiong

    2013-01-01

    Well-defined tertiary amine-functionalized cationic polylactides (CPLAs) are synthesized by thiol-ene click functionalization of an allyl-functionalized polylactide, and utilized here for the delivery of interleukin-8 (IL-8) siRNA via CPLA-IL-8 siRNA nanoplexes. The CPLAs possess remarkable hydrolytic degradability, and their cytotoxicity is relatively low. The CPLA-IL-8 siRNA nanoplexes can be readily taken up by prostate cancer cells, resulting in significant IL-8 gene silencing. It is found that the degradability and cytotoxicity of CPLAs, as well as the transfection efficiency of the CPLA-IL-8 siRNA nanoplexes, positively correlate with the amine mol% of CPLAs. PMID:23184827

  11. Solid-State NMR and DFT Studies on the Formation of Well-Defined Silica-Supported Tantallaaziridines: From Synthesis to Catalytic Application

    KAUST Repository

    Hamzaoui, Bilel

    2016-01-27

    Single-site, well-defined, silica-supported tantallaaziridine intermediates [≡Si-O-Ta(η2-NRCH2)(NMe2)2] [R=Me (2), Ph (3)] were prepared from silica-supported tetrakis(dimethylamido)tantalum [≡Si-O-Ta(NMe2)4] (1) and fully characterized by FTIR spectroscopy, elemental analysis, and 1H,13C HETCOR and DQ TQ solid-state (SS) NMR spectroscopy. The formation mechanism, by β-H abstraction, was investigated by SS NMR spectroscopy and supported by DFT calculations. The C-H activation of the dimethylamide ligand is favored for R=Ph. The results from catalytic testing in the hydroaminoalkylation of alkenes were consistent with the N-alkyl aryl amine substrates being more efficient than N-dialkyl amines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Bacteriophage Procurement for Therapeutic Purposes.

    Science.gov (United States)

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

    2016-01-01

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

  13. Bacteriophage biocontrol of foodborne pathogens.

    Science.gov (United States)

    Kazi, Mustafa; Annapure, Uday S

    2016-03-01

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

  14. Liposome-Encapsulated Bacteriophages for Enhanced Oral Phage Therapy against Salmonella spp.

    Science.gov (United States)

    Colom, Joan; Cano-Sarabia, Mary; Otero, Jennifer; Cortés, Pilar; Maspoch, Daniel; Llagostera, Montserrat

    2015-07-01

    Bacteriophages UAB_Phi20, UAB_Phi78, and UAB_Phi87 were encapsulated in liposomes, and their efficacy in reducing Salmonella in poultry was then studied. The encapsulated phages had a mean diameter of 309 to 326 nm and a positive charge between +31.6 and +35.1 mV (pH 6.1). In simulated gastric fluid (pH 2.8), the titer of nonencapsulated phages decreased by 5.7 to 7.8 log units, whereas encapsulated phages were significantly more stable, with losses of 3.7 to 5.4 log units. The liposome coating also improved the retention of bacteriophages in the chicken intestinal tract. When cocktails of the encapsulated and nonencapsulated phages were administered to broilers, after 72 h the encapsulated phages were detected in 38.1% of the animals, whereas the nonencapsulated phages were present in only 9.5%. The difference was significant. In addition, in an in vitro experiment, the cecal contents of broilers promoted the release of the phages from the liposomes. In broilers experimentally infected with Salmonella, the daily administration of the two cocktails for 6 days postinfection conferred similar levels of protection against Salmonella colonization. However, once treatment was stopped, protection by the nonencapsulated phages disappeared, whereas that provided by the encapsulated phages persisted for at least 1 week, showing the enhanced efficacy of the encapsulated phages in protecting poultry against Salmonella over time. The methodology described here allows the liposome encapsulation of phages of different morphologies. The preparations can be stored for at least 3 months at 4°C and could be added to the drinking water and feed of animals.

  15. Application of bacteriophages specific to hydrogen sulfide-producing bacteria in raw poultry by-products.

    Science.gov (United States)

    Gong, Chao; Liu, Xiaohua; Jiang, Xiuping

    2014-03-01

    Hydrogen sulfide-producing bacteria (SPB) can spoil raw animal materials and release harmful hydrogen sulfide (H2S) gas. The objective of this study was to apply a SPB-specific bacteriophage cocktail to control H2S production by SPB in different raw poultry by-products in the laboratory (20, 30, and 37°C) and greenhouse (average temperature 29 to 31°C, humidity 34.8 to 59.8%, and light intensity 604.8 Wm(2)) by simulating transportation and a rendering facility. The amount of H2S production was determined using either test strips impregnated with lead acetate or a H2S monitor. In the laboratory, phage treatment applied to fresh chicken meat inoculated with SPB, spoiled chicken meat, chicken guts, and chicken feathers reduced H2S production by approximately 25 to 69% at temperatures from 20 to 37°C. In the greenhouse, phage treatment achieved approximately a 30 to 85% reduction of H2S yield in chicken offal and feathers. Among all phage treatments, multiplicity of infection (MOI) of 100 exhibited the highest inhibitory activities against SPB on H2S production. Several factors such as initial SPB level, temperature, and MOI affect lytic activities of bacteriophages. Our study demonstrated that the phage cocktail is effective to reduce the production of H2S by SPB significantly in raw animal materials. This biological control method can control SPB in raw poultry by-products at ambient temperatures, leading to a safer working environment and high quality product with less nutrient degradation for the rendering industry.

  16. The importance of chemistry in creating well-defined nanoscopic embedded therapeutics: devices capable of the dual functions of imaging and therapy.

    Science.gov (United States)

    Nyström, Andreas M; Wooley, Karen L

    2011-10-18

    Nanomedicine is a rapidly evolving field, for which polymer building blocks are proving useful for the construction of sophisticated devices that provide enhanced diagnostic imaging and treatment of disease, known as theranostics. These well-defined nanoscopic objects have high loading capacities, can protect embedded therapeutic cargo, and offer control over the conditions and rates of release. Theranostics also offer external surface area for the conjugation of ligands to impart stealth characteristics and/or direct their interactions with biological receptors and provide a framework for conjugation of imaging agents to track delivery to diseased site(s). The nanoscopic dimensions allow for extensive biological circulation. The incorporation of such multiple functions is complicated, requiring exquisite chemical control during production and rigorous characterization studies to confirm the compositions, structures, properties, and performance. We are particularly interested in the study of nanoscopic objects designed for treatment of lung infections and acute lung injury, urinary tract infections, and cancer. This Account highlights our work over several years to tune the assembly of unique nanostructures. We provide examples of how the composition, structure, dimensions, and morphology of theranostic devices can tune their performance as drug delivery agents for the treatment of infectious diseases and cancer. The evolution of nanostructured materials from relatively simple overall shapes and internal morphologies to those of increasing complexity is driving the development of synthetic methodologies for the preparation of increasingly complex nanomedicine devices. Our nanomedicine devices are derived from macromolecules that have well-defined compositions, structures, and topologies, which provide a framework for their programmed assembly into nanostructures with controlled sizes, shapes, and morphologies. The inclusion of functional units within selective

  17. MixPlore: A Cocktail-Based Media Performance Using Tangible User Interfaces

    Science.gov (United States)

    Lee, Zune; Chang, Sungkyun; Lim, Chang Young

    This paper presents MixPlore, a framework for a cocktail-based live media performance. It aims to maximize the pleasure of mixology, presenting the cocktail as a plentiful art medium where people can fully enjoy new synesthetic contents by the integration of bartending and musical creation. For this, we fabricated Tangible User Interfaces (TUIs): tin, glass, muddler, and costume display, etc. The basic idea of performance and music composition is to follow the process of making cocktails. At the end of every repertoire, the performer provides the resultant 'sonic cocktails' to audience.

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

    Science.gov (United States)

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

    2013-12-01

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

  19. The susceptibility of Pseudomonas aeruginosa strains from cystic fibrosis patients to bacteriophages.

    Science.gov (United States)

    Essoh, Christiane; Blouin, Yann; Loukou, Guillaume; Cablanmian, Arsher; Lathro, Serge; Kutter, Elizabeth; Thien, Hoang Vu; Vergnaud, Gilles; Pourcel, Christine

    2013-01-01

    Phage therapy may become a complement to antibiotics in the treatment of chronic Pseudomonas aeruginosa infection. To design efficient therapeutic cocktails, the genetic diversity of the species and the spectrum of susceptibility to bacteriophages must be investigated. Bacterial strains showing high levels of phage resistance need to be identified in order to decipher the underlying mechanisms. Here we have selected genetically diverse P. aeruginosa strains from cystic fibrosis patients and tested their susceptibility to a large collection of phages. Based on plaque morphology and restriction profiles, six different phages were purified from "pyophage", a commercial cocktail directed against five different bacterial species, including P. aeruginosa. Characterization of these phages by electron microscopy and sequencing of genome fragments showed that they belong to 4 different genera. Among 47 P. aeruginosa strains, 13 were not lysed by any of the isolated phages individually or by pyophage. We isolated two new phages that could lyse some of these strains, and their genomes were sequenced. The presence/absence of a CRISPR-Cas system (Clustered Regularly Interspaced Short Palindromic Repeats and Crisper associated genes) was investigated to evaluate the role of the system in phage resistance. Altogether, the results show that some P. aeruginosa strains cannot support the growth of any of the tested phages belonging to 5 different genera, and suggest that the CRISPR-Cas system is not a major defence mechanism against these lytic phages.

  20. The susceptibility of Pseudomonas aeruginosa strains from cystic fibrosis patients to bacteriophages.

    Directory of Open Access Journals (Sweden)

    Christiane Essoh

    Full Text Available Phage therapy may become a complement to antibiotics in the treatment of chronic Pseudomonas aeruginosa infection. To design efficient therapeutic cocktails, the genetic diversity of the species and the spectrum of susceptibility to bacteriophages must be investigated. Bacterial strains showing high levels of phage resistance need to be identified in order to decipher the underlying mechanisms. Here we have selected genetically diverse P. aeruginosa strains from cystic fibrosis patients and tested their susceptibility to a large collection of phages. Based on plaque morphology and restriction profiles, six different phages were purified from "pyophage", a commercial cocktail directed against five different bacterial species, including P. aeruginosa. Characterization of these phages by electron microscopy and sequencing of genome fragments showed that they belong to 4 different genera. Among 47 P. aeruginosa strains, 13 were not lysed by any of the isolated phages individually or by pyophage. We isolated two new phages that could lyse some of these strains, and their genomes were sequenced. The presence/absence of a CRISPR-Cas system (Clustered Regularly Interspaced Short Palindromic Repeats and Crisper associated genes was investigated to evaluate the role of the system in phage resistance. Altogether, the results show that some P. aeruginosa strains cannot support the growth of any of the tested phages belonging to 5 different genera, and suggest that the CRISPR-Cas system is not a major defence mechanism against these lytic phages.

  1. Use of Bacteriophages to control bacterial pathogens

    Science.gov (United States)

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

  2. Programming Bacteriophages by Swapping Their Specificity Determinants.

    Science.gov (United States)

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

    2015-12-01

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

  3. Nanoscale bacteriophage biosensors beyond phage display.

    Science.gov (United States)

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

    2013-01-01

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

  4. Nanoscale bacteriophage biosensors beyond phage display

    Science.gov (United States)

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

    2013-01-01

    Bacteriophages are traditionally used for the development of phage display technology. Recently, their nanosized dimensions and ease with which genetic modifications can be made to their structure and function have put them in the spotlight towards their use in a variety of biosensors. In particular, the expression of any protein or peptide on the extraluminal surface of bacteriophages is possible by genetically engineering the genome. In addition, the relatively short replication time of bacteriophages offers researchers the ability to generate mass quantities of any given bacteriophage-based biosensor. Coupled with the emergence of various biomarkers in the clinic as a means to determine pathophysiological states, the development of current and novel technologies for their detection and quantification is imperative. In this review, we categorize bacteriophages by their morphology into M13-based filamentous bacteriophages and T4- or T7-based icosahedral bacteriophages, and examine how such advantages are utilized across a variety of biosensors. In essence, we take a comprehensive approach towards recent trends in bacteriophage-based biosensor applications and discuss their outlook with regards to the field of biotechnology. PMID:24143096

  5. Well-defined 4-arm stars with hydroxy-terminated polyethylene, polyethylene-b-polycaprolactone and polyethylene-b-(polymethyl methacrylate) 2 arms

    KAUST Repository

    Zhang, Zhen

    2016-07-20

    Bis-boron-thexyl-silaboracycle was prepared by hydroboration of 1,4-bis(methyldivinylsilyl)butane with thexylborane and used to initiate the polyhomologation of dimethylsulfoxonium methylide to afford well-defined hydroxy-terminated 4-arm polyethylene (PE) stars. The synthesized PE stars were transformed to (PE-b-PCL)4 starblock copolymers via the ring-opening polymerization of ϵ-caprolactone (CL) initiated by the hydroxyl end groups of (PE-OH)4 in the presence of P2-tBu phosphazene base. Esterification of the hydroxyl groups of the OH-terminated PE star with 2,2-dichloroacetyl chloride led to (PE-Cl2)4 which was used as initiator (eight initiating atom transfer radical polymerization, ATRP, sites) for the synthesis of (PE-b-PMMA2)4 dendrimer-like stars by the ATRP of methyl methacrylate (MMA). All intermediates and final products were characterized by high temperature gel permeation chromatography and proton nuclear magnetic resonance spectroscopy. © 2016 The Royal Society of Chemistry.

  6. A model electrode of well-defined geometry prepared by direct laser-induced decoration of nanoporous templates with Au-Ag@C nanoparticles

    Science.gov (United States)

    Schlicht, Stefanie; Kireev, Alexey; Vasileva, Anna; Grachova, Elena V.; Tunik, Sergey P.; Manshina, Alina A.; Bachmann, Julien

    2017-02-01

    We present an original type of model electrode system consisting of bimetallic Au-Ag nanoparticles embedded in an amorphous carbon matrix with an extremely well-defined geometry of parallel, straight, cylindrical macropores. The samples are prepared in one step by direct laser deposition of the metal/carbon composite onto the inner walls of a porous ‘anodic’ alumina matrix serving as a template. The coating is homogeneous from top to bottom of the pores, and the amount of material deposited can be tuned by the duration of the deposition procedure. As a test system, we demonstrate that a bimetallic Ag-Au@C system is catalytically active for the electrochemical oxidation of glucose in alkaline solution, the anodic reaction of a direct glucose fuel cell. Furthermore, the electrocatalytic current density increases with the amount of Ag-Au@C NPs deposited, up to a point at which the pores are clogged with it. This type of model system allows for the systematic study of geometric effects in fuel cell electrodes. It can be generalized to a number of different nanoparticle compositions, and thereby, to various electrocatalytic reactions.

  7. Structural analysis and anticoagulant activities of the novel sulfated fucan possessing a regular well-defined repeating unit from sea cucumber.

    Science.gov (United States)

    Wu, Mingyi; Xu, Li; Zhao, Longyan; Xiao, Chuang; Gao, Na; Luo, Lan; Yang, Lian; Li, Zi; Chen, Lingyun; Zhao, Jinhua

    2015-04-13

    Sulfated fucans, the complex polysaccharides, exhibit various biological activities. Herein, we purified two fucans from the sea cucumbers Holothuria edulis and Ludwigothurea grisea. Their structures were verified by means of HPGPC, FT-IR, GC-MS and NMR. As a result, a novel structural motif for this type of polymers is reported. The fucans have a unique structure composed of a central core of regular (1→2) and (1→3)-linked tetrasaccharide repeating units. Approximately 50% of the units from L. grisea (100% for H. edulis fucan) contain sides of oligosaccharides formed by nonsulfated fucose units linked to the O-4 position of the central core. Anticoagulant activity assays indicate that the sea cucumber fucans strongly inhibit human blood clotting through the intrinsic pathways of the coagulation cascade. Moreover, the mechanism of anticoagulant action of the fucans is selective inhibition of thrombin activity by heparin cofactor II. The distinctive tetrasaccharide repeating units contribute to the anticoagulant action. Additionally, unlike the fucans from marine alga, although the sea cucumber fucans have great molecular weights and affluent sulfates, they do not induce platelet aggregation. Overall, our results may be helpful in understanding the structure-function relationships of the well-defined polysaccharides from invertebrate as new types of safer anticoagulants.

  8. High-Hall-Mobility Al-Doped ZnO Films Having Textured Polycrystalline Structure with a Well-Defined (0001) Orientation.

    Science.gov (United States)

    Nomoto, Junichi; Makino, Hisao; Yamamoto, Tetsuya

    2016-12-01

    Five hundred-nanometer-thick ZnO-based textured polycrystalline films consisting of 490-nm-thick Al-doped ZnO (AZO) films deposited on 10-nm-thick Ga-doped ZnO (GZO) films exhibited a high Hall mobility (μ H) of 50.1 cm(2)/Vs with a carrier concentration (N) of 2.55 × 10(20) cm(-3). Firstly, the GZO films were prepared on glass substrates by ion plating with dc arc discharge, and the AZO films were then deposited on the GZO films by direct current magnetron sputtering (DC-MS). The GZO interface layers with a preferential c-axis orientation play a critical role in producing AZO films with texture development of a well-defined (0001) orientation, whereas 500-nm-thick AZO films deposited by only DC-MS showed a mixture of the c-plane and the other plane orientation, to exhibit a μ H of 38.7 cm(2)/Vs with an N of 2.22 × 10(20) cm(-3).

  9. Structural Analysis and Anticoagulant Activities of the Novel Sulfated Fucan Possessing a Regular Well-Defined Repeating Unit from Sea Cucumber

    Directory of Open Access Journals (Sweden)

    Mingyi Wu

    2015-04-01

    Full Text Available Sulfated fucans, the complex polysaccharides, exhibit various biological activities. Herein, we purified two fucans from the sea cucumbers Holothuria edulis and Ludwigothurea grisea. Their structures were verified by means of HPGPC, FT-IR, GC–MS and NMR. As a result, a novel structural motif for this type of polymers is reported. The fucans have a unique structure composed of a central core of regular (1→2 and (1→3-linked tetrasaccharide repeating units. Approximately 50% of the units from L. grisea (100% for H. edulis fucan contain sides of oligosaccharides formed by nonsulfated fucose units linked to the O-4 position of the central core. Anticoagulant activity assays indicate that the sea cucumber fucans strongly inhibit human blood clotting through the intrinsic pathways of the coagulation cascade. Moreover, the mechanism of anticoagulant action of the fucans is selective inhibition of thrombin activity by heparin cofactor II. The distinctive tetrasaccharide repeating units contribute to the anticoagulant action. Additionally, unlike the fucans from marine alga, although the sea cucumber fucans have great molecular weights and affluent sulfates, they do not induce platelet aggregation. Overall, our results may be helpful in understanding the structure-function relationships of the well-defined polysaccharides from invertebrate as new types of safer anticoagulants.

  10. Synthesis of well-defined structurally silica-nonlinear polymer core-shell nanoparticles via the surface-initiated atom transfer radical polymerization

    Science.gov (United States)

    Chen, Jiucun; Hu, Min; Zhu, Wendong; Li, Yaping

    2011-05-01

    We report on the synthesis of the well-defined structurally silica-nonlinear polymer core-shell nanoparticles via the surface-initiated atom transfer radical polymerization. At first, 3-(2-bromoisobutyramido)propyl(triethoxy)-silane (the ATRP initiator) was prepared by the reaction of 3-aminopropyltriethoxysilane with 2-bromoisobutyryl bromide. The ATRP initiator was covalently attached onto the nanosilica surface. The subsequent ATRP of HEMA from the initiator-attached SiO 2 surface was carried out in order to afforded functional nanoparticles bearing a hydroxyl moiety at the chain end, SiO 2-g-PHEMA-Br. The esterification reaction of pendent hydroxyl moieties of PHEMA segment with 2-bromoisobutyryl bromide afforded the SiO 2-based multifunctional initiator, SiO 2-g-PHEMA(-Br)-Br, bearing one bromine moiety on each monomer repeating unit within the PHEMA segment. Finally, the synthesis of SiO 2-g-PHEMA(-g-PSt)-b-PSt was accomplished by the ATRP of St monomer using SiO 2-g-PHEMA(-Br)-Br as multifunctional initiator. These organic/inorganic hybrid materials have been extensively characterized by FT-IR, XPS, TG, and TEM.

  11. High-Hall-Mobility Al-Doped ZnO Films Having Textured Polycrystalline Structure with a Well-Defined (0001) Orientation

    Science.gov (United States)

    Nomoto, Junichi; Makino, Hisao; Yamamoto, Tetsuya

    2016-06-01

    Five hundred-nanometer-thick ZnO-based textured polycrystalline films consisting of 490-nm-thick Al-doped ZnO (AZO) films deposited on 10-nm-thick Ga-doped ZnO (GZO) films exhibited a high Hall mobility ( μ H) of 50.1 cm2/Vs with a carrier concentration ( N) of 2.55 × 1020 cm-3. Firstly, the GZO films were prepared on glass substrates by ion plating with dc arc discharge, and the AZO films were then deposited on the GZO films by direct current magnetron sputtering (DC-MS). The GZO interface layers with a preferential c-axis orientation play a critical role in producing AZO films with texture development of a well-defined (0001) orientation, whereas 500-nm-thick AZO films deposited by only DC-MS showed a mixture of the c-plane and the other plane orientation, to exhibit a μ H of 38.7 cm2/Vs with an N of 2.22 × 1020 cm-3.

  12. A facile glovebox-free strategy to significantly accelerate the syntheses of well-defined polypeptides by N-carboxyanhydride (NCA) ring opening polymerizations.

    Science.gov (United States)

    Zou, Jiong; Fan, Jingwei; He, Xun; Zhang, Shiyi; Wang, Hai; Wooley, Karen L

    2013-05-28

    A facile N2 flow-accelerated N-carboxyanhydride ring opening polymerization (NCA ROP) is demonstrated, herein, with rigorous kinetic studies to evaluate the methodology in detail. By using n-hexylamine as initiator and γ-benzyl-L-glutamate N-carboxyanhydride (BLG-NCA) as monomer, the NCA ROP via a normal amine mechanism (NAM) reached 90% conversion in 2 h under N2 flow at room temperature in a fume hood, much shorter than the time required for the same polymerization conducted in a glove box (14 h). The efficient removal of CO2 from the reaction by N2 flow drove the carbamic acid-amine equilibrium toward the formation of active nucleophilic amino termini and promoted polymerization. The detailed kinetic studies of the polymerization with different feed ratios and N2 flow rates were conducted, demonstrating the living feature of the NCA ROP and the tuning of the polymerization rate by simply changing the flow rate of N2. Maintenance of the reactivity of the amino ω-chain terminus and control during a subsequent polymerization were confirmed by performing chain extension reactions. The N2 flow method provides a new straightforward strategy to synthesize well-defined polypeptides with predictable molecular weights and narrow molecular weight distributions (PDI < 1.19).

  13. Preparation of Well-Defined Propargyl-Terminated Tetra-Arm Poly(N-isopropylacrylamides and Their Click Hydrogels Crosslinked with β-cyclodextrin

    Directory of Open Access Journals (Sweden)

    Jianquan Wang

    2016-03-01

    Full Text Available As an important class of reversible deactivation radical polymerization (RDRP, reversible addition fragmentation chain transfer (RAFT polymerization has attracted great attention attributed to its facile and flexible features to prepare well-defined polymers with different complex structures. In addition, the combination of RAFT with click chemistry provides more effective strategies to fabricate advanced functional materials. In this work, a series of temperature responsive tetra-arm telechelic poly(N-isopropylacrylamides (PNIPAs with propargyl end groups were prepared for the first time through RAFT and subsequent aminolysis/Michael addition modification. The temperature sensitivities of their aqueous solutions were researched via turbidity measurement. It was found that the phase transition temperature of obtained PNIPAs increased with their molecular weights ascribed to their distinctions in the hydrophobic/hydrophilic balance. Subsequently, β-cyclodextrin (β-CD functionalized with azide moieties was used to crosslink the prepared propargyl-terminated tetra-arm PNIPAs through click chemistry, fabricating corresponding hydrogels with thermoresponse. Similar to their precursors, the hydrogels demonstrated the same dependence of volume phase transition temperature (VPTT on their molecular weights. In addition, the incorporation of β-CD and the residual groups besides crosslinking may provide a platform for imparting additional functions such as inclusion and adsorption as well as further functionalization.

  14. 电位控制的固液界面有序纳米结构%Well defined nanostructures at solid /liquid interface under potential control

    Institute of Scientific and Technical Information of China (English)

    王栋; 万立骏; 白春礼

    2002-01-01

    The well defined nanostructures can be constructed at solid/liquid interface under potential control with ions, organic molecules or other objects. The molecule orientation and structure can be controlled by applying an electrode potential in electrolyte solution and the formation process can be monitored by electrochemical scanning tunneling microscopy. The so constructed nanostructure is potentially useful in future nano electronic devices fabrication.%在电极电势控制下,用原子、离子和有机分子在固液界面构筑了有序的纳米结构.利用电化学扫描隧道显微镜能够观察纳米结构的形成过程及电势控制下的结构转变和分子位相变化.这些纳米结构在未来的纳米电子器件的制造等领域有重要的应用价值.

  15. Rational and practical exfoliation of graphite using well-defined poly(3-hexylthiophene) for the preparation of conductive polymer/graphene composite.

    Science.gov (United States)

    Iguchi, Hiroki; Higashi, Chisato; Funasaki, Yuichi; Fujita, Keisuke; Mori, Atsunori; Nakasuga, Akira; Maruyama, Tatsuo

    2017-01-06

    Processing and manipulation of highly conductive pristine graphene in large quantities are still major challenges in the practical application of graphene for electric device. In the present study, we report the liquid-phase exfoliation of graphite in toluene using well-defined poly(3-hexylthiophene) (P3HT) to produce a P3HT/graphene composite. We synthesize and use regioregular P3HT with controlled molecular weights as conductive dispersants for graphene. Simple ultrasonication of graphite flakes with the P3HT successfully produces single-layer and few-layer graphene sheets dispersed in toluene. The produced P3HT/graphene composite can be used as conductive graphene ink, indicating that the P3HT/graphene composite has high electrical conductivity owing to the high conductivity of P3HT and graphene. The P3HT/graphene composite also works as an oxidation-resistant and conductive film for a copper substrate, which is due to the high gas-barrier property of graphene.

  16. A Two-Component Adhesive: Tau Fibrils Arise from a Combination of a Well-Defined Motif and Conformationally Flexible Interactions.

    Science.gov (United States)

    Xiang, Shengqi; Kulminskaya, Natalia; Habenstein, Birgit; Biernat, Jacek; Tepper, Katharina; Paulat, Maria; Griesinger, Christian; Becker, Stefan; Lange, Adam; Mandelkow, Eckhard; Linser, Rasmus

    2017-02-22

    Fibrillar aggregates of Aβ and Tau in the brain are the major hallmarks of Alzheimer's disease. Most Tau fibers have a twisted appearance, but the twist can be variable and even absent. This ambiguity, which has also been associated with different phenotypes of tauopathies, has led to controversial assumptions about fibril constitution, and it is unclear to-date what the molecular causes of this polymorphism are. To tackle this question, we used solid-state NMR strategies providing assignments of non-seeded three-repeat-domain Tau(3RD) with an inherent heterogeneity. This is in contrast to the general approach to characterize the most homogeneous preparations by construct truncation or intricate seeding protocols. Here, carbon and nitrogen chemical-shift conservation between fibrils revealed invariable secondary-structure properties, however, with inter-monomer interactions variable among samples. Residues with variable amide shifts are localized mostly to N- and C-terminal regions within the rigid beta structure in the repeat region of Tau(3RD). By contrast, the hexapeptide motif in repeat R3, a crucial motif for fibril formation, shows strikingly low variability of all NMR parameters: Starting as a nucleation site for monomer-monomer contacts, this six-residue sequence element also turns into a well-defined structural element upon fibril formation. Given the absence of external causes in vitro, the interplay of structurally differently conserved elements in this protein likely reflects an intrinsic property of Tau fibrils.

  17. Spatially well-defined binary brushes of poly(ethylene glycol)s for micropatterning of active proteins on anti-fouling surfaces.

    Science.gov (United States)

    Xu, F J; Li, H Z; Li, J; Teo, Y H Eric; Zhu, C X; Kang, E T; Neoh, K G

    2008-12-01

    We report a novel method for micropatterning of active proteins on anti-fouling surfaces via spatially well-defined and dense binary poly(ethylene glycol)s (PEGs) brushes with controllable protein-docking sites. Binary brushes of poly(poly(ethylene glycol) methacrylate-co-poly(ethylene glycol)methyl ether methacrylate), or P(PEGMA-co-PEGMEMA), and poly(poly(ethylene glycol)methyl ether methacrylate), or P(PEGMEMA), were prepared via consecutive surface-initiated atom transfer radical polymerizations (SI-ATRPs) from a resist-micropatterned Si(100) wafer surface. The terminal hydroxyl groups on the side chains of PEGMA units in the P(PEGMA-co-PEGMEMA) microdomains were activated directly by 1,1'-carbonyldiimidazole (CDI) for the covalent coupling of human immunoglobulin (IgG) (as a model active protein). The resulting IgG-coupled PEG microdomains interact only and specifically with target anti-IgG, while the other PEG microregions effectively prevent specific and non-specific protein fouling. When extended to other active biomolecules, microarrays for specific and non-specific analyte interactions with a high signal-to-noise ratio could be readily tailored.

  18. Electrically templated dewetting of a UV-curable prepolymer film for the fabrication of a concave microlens array with well-defined curvature.

    Science.gov (United States)

    Li, Xiangming; Tian, Hongmiao; Ding, Yucheng; Shao, Jinyou; Wei, Yuping

    2013-10-23

    This paper presents an economic method, based on electrically templated dewetting of a UV-curable prepolymer, for fabricating a concave microlens array (MLA) of high quality and high density. In our strategy, a voltage is applied to an electrode pair consisting of a conductive substrate coated with a UV-curable prepolymer film and a microhole-arrayed silicon template, sandwiching an air gap, to dewet the prepolymer film into a curved air-liquid interface. At or beyond a critical voltage, the curved prepolymer can be pulled quickly into contact with the protrusive underside of the silicon template. Contact of the prepolymer with the template can be detected by monitoring the leaky current in the polymer, followed by a UV curing of the prepolymer. Finally, by separating the mold from the solidified polymer, a concave MLA is obtained. The curvature of the MLA can be well-defined simply by changing the air gap between the mold and prepolymer film. Besides, the dewetting strategy results in a much smaller adhesion area between the mold and solidified polymer structures, which allows for easy separation of the mold from the MLA in a large-area operation.

  19. Rational and practical exfoliation of graphite using well-defined poly(3-hexylthiophene) for the preparation of conductive polymer/graphene composite

    Science.gov (United States)

    Iguchi, Hiroki; Higashi, Chisato; Funasaki, Yuichi; Fujita, Keisuke; Mori, Atsunori; Nakasuga, Akira; Maruyama, Tatsuo

    2017-01-01

    Processing and manipulation of highly conductive pristine graphene in large quantities are still major challenges in the practical application of graphene for electric device. In the present study, we report the liquid-phase exfoliation of graphite in toluene using well-defined poly(3-hexylthiophene) (P3HT) to produce a P3HT/graphene composite. We synthesize and use regioregular P3HT with controlled molecular weights as conductive dispersants for graphene. Simple ultrasonication of graphite flakes with the P3HT successfully produces single-layer and few-layer graphene sheets dispersed in toluene. The produced P3HT/graphene composite can be used as conductive graphene ink, indicating that the P3HT/graphene composite has high electrical conductivity owing to the high conductivity of P3HT and graphene. The P3HT/graphene composite also works as an oxidation-resistant and conductive film for a copper substrate, which is due to the high gas-barrier property of graphene.

  20. Structure-interfacial properties relationship and quantification of the amphiphilicity of well-defined ionic and non-ionic surfactants using the PIT-slope method.

    Science.gov (United States)

    Ontiveros, Jesús F; Pierlot, Christel; Catté, Marianne; Molinier, Valérie; Salager, Jean-Louis; Aubry, Jean-Marie

    2015-06-15

    The Phase Inversion Temperature of a reference C10E4/n-Octane/Water system exhibits a quasi-linear variation versus the mole fraction of a second surfactant S2 added in the mixture. This variation was recently proposed as a classification tool to quantify the Hydrophilic-Lipophilic Balance (HLB) of commercial surfactants. The feasibility of the so-called PIT-slope method for a wide range of well-defined non-ionic and ionic surfactants is investigated. The comparison of various surfactants having the same dodecyl chain tail allows to rank the polar head hydrophilicity as: SO3Na⩾SO4Na⩾NMe3Br>E2SO3Na≈CO2Na⩾E1SO3Na⩾PhSO3Na>Isosorbide(exo)SO4Na≫IsosorbideendoSO4Na≫E8⩾NMe2O>E7>E6⩾Glucosyl>E5⩾Diglyceryl⩾E4>E3>E2≈Isosorbide(exo)>Glyceryl>Isosorbide(endo). The influence on the surfactant HLB of other structural parameters, i.e. hydrophobic chain length, unsaturation, replacement of Na(+) by K(+) counterion, and isomerism is also investigated. Finally, the method is successfully used to predict the optimal formulation of a new bio-based surfactant, 1-O-dodecyldiglycerol, when performing an oil scan at 25 °C.

  1. A Well-Defined Silicon Nanocone-Carbon Structure for Demonstrating Exclusive Influences of Carbon Coating on Silicon Anode of Lithium-Ion Batteries.

    Science.gov (United States)

    Wang, Chao; Luo, Fei; Lu, Hao; Rong, Xiaohui; Liu, Bonan; Chu, Geng; Sun, Yu; Quan, Baogang; Zheng, Jieyun; Li, Junjie; Gu, Changzhi; Qiu, Xinping; Li, Hong; Chen, Liquan

    2017-01-25

    Nanotechnology and carbon coating have been applied to silicon anodes to achieve excellent lithium-ion batteries, but the exclusive influence of carbon coating on solid-electrolyte interphase (SEI) formation is difficult to exhibit distinctly because of the impurity and morphological irregularity of most nanostructured anodes. Here, we design a silicon nanocone-carbon (SNC-C) composite structure as a model anode to demonstrate the significant influences of carbon coating on SEI formation and electrochemical performance, unaffectedly as a result of pure electrode component and distinctly due to regular nanocone morphology. As demonstrated by morphological and elemental analysis, compared to the SNC electrode, the SNC-C electrode maintains a thinner SEI layer (∼10 nm) and more stable structure during cycling as well as longer cycle life (>725 cycles), higher Coulombic efficiency (>99%), and lower electrode polarization. This well-defined structure clearly shows the interface stability attributed to carbon coating and is promising in fundamental research of the silicon anode.

  2. Typing of bacteriophages by randomly amplified polymorphic DNA (RAPD)-PCR to assess genetic diversity.

    Science.gov (United States)

    Gutiérrez, Diana; Martín-Platero, Antonio M; Rodríguez, Ana; Martínez-Bueno, Manuel; García, Pilar; Martínez, Beatriz

    2011-09-01

    The recent boom in phage therapy and phage biocontrol requires the design of suitable cocktails of genetically different bacteriophages. The current methods for typing phages need significant quantities of purified DNA, may require a priori genetic information and are cost and time consuming. We have evaluated the randomly amplified polymorphic DNA (RAPD)-PCR technique to produce unique and reproducible band patterns from 26 different bacteriophages infecting Staphylococcus epidermidis, Staphylococcus aureus, Lactococcus lactis, Escherichia coli, Streptococcus thermophilus, Bacillus subtilis and Lactobacillus casei bacterial strains. Initially, purified DNA and phage suspensions of seven selected phages were used as a template. The conditions that were found to be optimal 8 μM of 10-mer primers, 3 μM magnesium oxalacetate and 5% dimethyl sulfoxide. The RAPD genomic fingerprints using a phage titer suspension higher than 10(9) PFU mL(-1) were highly reproducible. Clustering by the Pearson correlation coefficient and the unweighted pair group method with arithmetic averages clustering algorithm correlated largely with genetically different phages infecting the same bacterial species, although closely related phages with a similar DNA restriction pattern were indistinguishable. The results support the use of RAPD-PCR for quick typing of phage isolates and preliminary assessment of their genetic diversity bypassing tedious DNA purification protocols and previous knowledge of their sequence.

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

    Science.gov (United States)

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

    2013-03-01

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

  4. On-Demand Isolation of Bacteriophages Against Drug-Resistant Bacteria for Personalized Phage Therapy.

    Science.gov (United States)

    Mattila, Sari; Ruotsalainen, Pilvi; Jalasvuori, Matti

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Sari eMattila

    2015-11-01

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

  6. Controllable assembly of well-defined monodisperse Au nanoparticles on hierarchical ZnO microspheres for enhanced visible-light-driven photocatalytic and antibacterial activity

    Science.gov (United States)

    Wang, Yuan; Fang, Hua-Bin; Zheng, Yan-Zhen; Ye, Rongqin; Tao, Xia; Chen, Jian-Feng

    2015-11-01

    A high-efficiency visible-light-driven photocatalyst composed of homogeneously distributed Au nanoparticles (AuNPs) well-defined on hierarchical ZnO microspheres (ZMS) via a controllable layer-by-layer self-assembly technique is demonstrated. The gradual growth of the characteristic absorption bands of Au loaded on ZnO in the visible light region with an increasing number of assemblies indicates the enhancement of the light harvesting ability of the ZMS/Au composites as well as the reproducibility and controllability of the entire assembly process. Results on the photoelectrochemical performance characterized by EIS and transient photocurrent response spectra indicate that the ZMS/Au composites possess increased photoinduced charge separation and transfer efficiency compared to the pure ZMS film. As a result, the hybrid composites exhibited enhanced decomposition activity for methylene blue and salicylic acid as well as antibacterial activity in killing S. aureus and E. coli under visible light irradiation. It can be noted that well-distributed Au components even at a rather low Au/ZnO weight ratio of ~1.2% also exhibited extraordinary photocatalysis. Such a facile and controllable self-assembly approach may be viable for preparing high-performance visible-light-driven ZMS/Au photocatalysts in a simple and controllable way, and consequently, the technology may extend to other plasmon-enhanced heterostructures made of nanostructured semiconductors and noble metals for great potential application in environmental protection.A high-efficiency visible-light-driven photocatalyst composed of homogeneously distributed Au nanoparticles (AuNPs) well-defined on hierarchical ZnO microspheres (ZMS) via a controllable layer-by-layer self-assembly technique is demonstrated. The gradual growth of the characteristic absorption bands of Au loaded on ZnO in the visible light region with an increasing number of assemblies indicates the enhancement of the light harvesting ability of

  7. The in vivo efficacy of two administration routes of a phage cocktail to reduce numbers of Campylobacter coli and Campylobacter jejuni in chickens

    Directory of Open Access Journals (Sweden)

    Carvalho Carla M

    2010-09-01

    Full Text Available Abstract Background Poultry meat is one of the most important sources of human campylobacteriosis, an acute bacterial enteritis which is a major problem worldwide. Campylobacter coli and Campylobacter jejuni are the most common Campylobacter species associated with this disease. These pathogens live in the intestinal tract of most avian species and under commercial conditions they spread rapidly to infect a high proportion of the flock, which makes their treatment and prevention very difficult. Bacteriophages (phages are naturally occurring predators of bacteria with high specificity and also the capacity to evolve to overcome bacterial resistance. Therefore phage therapy is a promising alternative to antibiotics in animal production. This study tested the efficacy of a phage cocktail composed of three phages for the control of poultry infected with C. coli and C. jejuni. Moreover, it evaluated the effectiveness of two routes of phage administration (by oral gavage and in feed in order to provide additional information regarding their future use in a poultry unit. Results The results indicate that experimental colonisation of chicks was successful and that the birds showed no signs of disease even at the highest dose of Campylobacter administered. The phage cocktail was able to reduce the titre of both C. coli and C. jejuni in faeces by approximately 2 log10 cfu/g when administered by oral gavage and in feed. This reduction persisted throughout the experimental period and neither pathogen regained their former numbers. The reduction in Campylobacter titre was achieved earlier (2 days post-phage administration when the phage cocktail was incorporated in the birds' feed. Campylobacter strains resistant to phage infection were recovered from phage-treated chickens at a frequency of 13%. These resistant phenotypes did not exhibit a reduced ability to colonize the chicken guts and did not revert to sensitive types. Conclusions Our findings provide

  8. Terminal Uranium(V/VI) Nitride Activation of Carbon Dioxide and Carbon Disulfide: Factors Governing Diverse and Well-Defined Cleavage and Redox Reactions.

    Science.gov (United States)

    Cleaves, Peter A; Kefalidis, Christos E; Gardner, Benedict M; Tuna, Floriana; McInnes, Eric J L; Lewis, William; Maron, Laurent; Liddle, Stephen T

    2017-02-24

    The reactivity of terminal uranium(V/VI) nitrides with CE2 (E=O, S) is presented. Well-defined C=E cleavage followed by zero-, one-, and two-electron redox events is observed. The uranium(V) nitride [U(Tren(TIPS) )(N)][K(B15C5)2 ] (1, Tren(TIPS) =N(CH2 CH2 NSiiPr3 )3 ; B15C5=benzo-15-crown-5) reacts with CO2 to give [U(Tren(TIPS) )(O)(NCO)][K(B15C5)2 ] (3), whereas the uranium(VI) nitride [U(Tren(TIPS) )(N)] (2) reacts with CO2 to give isolable [U(Tren(TIPS) )(O)(NCO)] (4); complex 4 rapidly decomposes to known [U(Tren(TIPS) )(O)] (5) with concomitant formation of N2 and CO proposed, with the latter trapped as a vanadocene adduct. In contrast, 1 reacts with CS2 to give [U(Tren(TIPS) )(κ(2) -CS3 )][K(B15C5)2 ] (6), 2, and [K(B15C5)2 ][NCS] (7), whereas 2 reacts with CS2 to give [U(Tren(TIPS) )(NCS)] (8) and "S", with the latter trapped as Ph3 PS. Calculated reaction profiles reveal outer-sphere reactivity for uranium(V) but inner-sphere mechanisms for uranium(VI); despite the wide divergence of products the initial activation of CE2 follows mechanistically related pathways, providing insight into the factors of uranium oxidation state, chalcogen, and NCE groups that govern the subsequent divergent redox reactions that include common one-electron reactions and a less-common two-electron redox event. Caution, we suggest, is warranted when utilising CS2 as a reactivity surrogate for CO2 .

  9. On-line optical and X-ray spectroscopies with crystallography: an integrated approach for determining metalloprotein structures in functionally well defined states.

    Science.gov (United States)

    Ellis, Mark J; Buffey, Steven G; Hough, Michael A; Hasnain, S Samar

    2008-09-01

    X-ray-induced redox changes can lead to incorrect assignments of the functional states of metals in metalloprotein crystals. The need for on-line monitoring of the status of metal ions (and other chromophores) during protein crystallography experiments is of growing importance with the use of intense synchrotron X-ray beams. Significant efforts are therefore being made worldwide to combine different spectroscopies in parallel with X-ray crystallographic data collection. Here the implementation and utilization of optical and X-ray absorption spectroscopies on the modern macromolecular crystallography (MX) beamline 10, at the SRS, Daresbury Laboratory, is described. This beamline is equipped with a dedicated monolithic energy-dispersive X-ray fluorescence detector, allowing X-ray absorption spectroscopy (XAS) measurements to be made in situ on the same crystal used to record the diffraction data. In addition, an optical microspectrophotometer has been incorporated on the beamline, thus facilitating combined MX, XAS and optical spectroscopic measurements. By uniting these techniques it is also possible to monitor the status of optically active and optically silent metal centres present in a crystal at the same time. This unique capability has been applied to observe the results of crystallographic data collection on crystals of nitrite reductase from Alcaligenes xylosoxidans, which contains both type-1 and type-2 Cu centres. It is found that the type-1 Cu centre photoreduces quickly, resulting in the loss of the 595 nm peak in the optical spectrum, while the type-2 Cu centre remains in the oxidized state over a much longer time period, for which independent confirmation is provided by XAS data as this centre has an optical spectrum which is barely detectable using microspectrophotometry. This example clearly demonstrates the importance of using two on-line methods, spectroscopy and XAS, for identifying well defined redox states of metalloproteins during

  10. Musical training, individual differences and the cocktail party problem.

    Science.gov (United States)

    Swaminathan, Jayaganesh; Mason, Christine R; Streeter, Timothy M; Best, Virginia; Kidd, Gerald; Patel, Aniruddh D

    2015-06-26

    Are musicians better able to understand speech in noise than non-musicians? Recent findings have produced contradictory results. Here we addressed this question by asking musicians and non-musicians to understand target sentences masked by other sentences presented from different spatial locations, the classical 'cocktail party problem' in speech science. We found that musicians obtained a substantial benefit in this situation, with thresholds ~6 dB better than non-musicians. Large individual differences in performance were noted particularly for the non-musically trained group. Furthermore, in different conditions we manipulated the spatial location and intelligibility of the masking sentences, thus changing the amount of 'informational masking' (IM) while keeping the amount of 'energetic masking' (EM) relatively constant. When the maskers were unintelligible and spatially separated from the target (low in IM), musicians and non-musicians performed comparably. These results suggest that the characteristics of speech maskers and the amount of IM can influence the magnitude of the differences found between musicians and non-musicians in multiple-talker "cocktail party" environments. Furthermore, considering the task in terms of the EM-IM distinction provides a conceptual framework for future behavioral and neuroscientific studies which explore the underlying sensory and cognitive mechanisms contributing to enhanced "speech-in-noise" perception by musicians.

  11. Transcription regulation mechanisms of bacteriophages

    Science.gov (United States)

    Yang, Haiquan; Ma, Yingfang; Wang, Yitian; Yang, Haixia; Shen, Wei; Chen, Xianzhong

    2014-01-01

    Phage diversity significantly contributes to ecology and evolution of new bacterial species through horizontal gene transfer. Therefore, it is essential to understand the mechanisms underlying phage-host interactions. After initial infection, the phage utilizes the transcriptional machinery of the host to direct the expression of its own genes. This review presents a view on the transcriptional regulation mechanisms of bacteriophages, and its contribution to phage diversity and classification. Through this review, we aim to broaden the understanding of phage-host interactions while providing a reference source for researchers studying the regulation of phage transcription. PMID:25482231

  12. Fragment-based cocktail crystallography by the Medical Structural Genomics of Pathogenic Protozoa Consortium

    Science.gov (United States)

    Verlinde, Christophe L.M.J.; Fan, Erkang; Shibata, Sayaka; Zhang, Zongsheng; Sun, Zhihua; Deng, Wei; Ross, Jennifer; Kim, Jessica; Xiao, Liren; Arakaki, Tracy L.; Bosch, Jürgen; Caruthers, Jonathan M.; Larson, Eric T.; LeTrong, Isolde; Napuli, Alberto; Kelly, Angela; Mueller, Natasha; Zucker, Frank; Van Voorhis, Wesley C.; Buckner, Frederick S.; Merritt, Ethan A.; Hol, Wim G.J.

    2010-01-01

    The history of fragment-based drug discovery, with an emphasis on crystallographic methods, is sketched, illuminating various contributions, including our own, which preceded the industrial development of the method. Subsequently, the creation of the BMSC fragment cocktails library is described. The BMSC collection currently comprises 68 cocktails of 10 compounds that are shape-wise diverse. The utility of these cocktails for initiating lead discovery in structure-based drug design has been explored by soaking numerous protein crystals obtained by our MSGPP (Medical Structural Genomics of Pathogenic Protozoa) consortium. Details of the fragment selection and cocktail design procedures, as well as examples of the successes obtained are given. The BMSC Fragment Cocktail recipes are available free of charge and are in use in over 20 academic labs. PMID:19929835

  13. High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rocker, J.; Cornu, D.; Kieseritzky, E.; Hänsel-Ziegler, W.; Freund, H.-J. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Seiler, A. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Laboratorium für Applikationen der Synchrotronstrahlung, KIT Campus Süd, Kaiserstr. 12, 76131 Karlsruhe (Germany); Bondarchuk, O. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); CIC energiGUNE, Parque Tecnologico, C/Albert Einstein 48, CP 01510 Minano (Alava) (Spain); Risse, T., E-mail: risse@chemie.fu-berlin.de [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)

    2014-08-01

    A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of the resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect paramagnetic

  14. Hydro-Metathesis of Long-Chain Olefin (1-decene) using Well-Defined Silica-Supported Tungsten (VI), Molybdenum (VI) and Tantalum (V) Catalysts

    KAUST Repository

    Saidi, Aya

    2016-11-01

    Nowadays, catalysis lies at the heart of economy growth mainly in the petroleum industry. Catalysis can offer real and potential solutions to the current challenges for a long-term sustainable energy, green chemistry, and environmental protection. In this context, one of the most important and future prosperity promising catalytic applications in the petrochemical field is hydrocarbons metathesis; it consists on the conversion of both renewable and non-petroleum fossil carbon sources to transportation fuels. Olefin metathesis has become one of the standard methodologies for constructing C-C bonds in many organic transformation reactions. This owed to the numerous types of metathesis reactions that have been developed, for example, enyne, ring-opening and closing, self and cross metathesis, etc. But the one step conversion of olefin to alkanes has not been studied much. Recently, only one such a work has been published for the hydro-metathesis of propylene by tantalum hydride supported on KCC-1 in dynamic reactor. With this knowledge, we thought to study the hydro-metathesis using liquid olefin (1-decene). Another aspect of using 1-decene comes from our previous experience on metathesis of n-decane where the first step is the conversion of decane to 1-decene and subsequently to different chain length alkanes with W-alkyl/alkylidene catalyst. In this way, it would be easy for us to use different catalysts and compare them with parent catalyst concerning TON. We found 100% conversion with TON of 1010 using supported WMe6 onto SiO2-700 [(≡Si-O-)WMe5] against the previous results for n-decane showing 20% conversion and TON of 153. In this work, we disclose the hydro-metathesis reaction of 1-decene using well-defined silica supported W(VI), Mo(VI) and Ta(V) alkyl catalysts in batch reactor condition. This work is divided into three major sections; first chapter contains an introduction to the field of catalysis and surface organometallic chemistry. In second chapter

  15. Generation of Well-Defined Pairs of Silylamine on Highly Dehydroxylated SBA-15: Application to the Surface Organometallic Chemistry of Zirconium

    KAUST Repository

    Azzi, Joachim

    2012-11-01

    Design of a new well-defined surface organometallic species [O-(=Si–NH)2Zr(IV)Np2] has been obtained by reaction of tetraneopentyl zirconium (ZrNp4) on SBA-15 surface displaying mainly silylamine pairs [O-(=Si–NH2)2]. These surface species have been achieved by an ammonia treatment of a highly dehydroxylated SBA-15 at 1000°C (SBA-151000). This support is known to contain mainly strained reactive siloxane bridges (≡Si-O-Si≡)[1] along with a small amount of isolated plus germinal silanols =Si(OH)2. Chemisorption of ammonia occurs primarily by opening these siloxane bridges[2] to generate silanol/silylamine pairs [O-(=Si–NH2)(=SiOH)] followed by substitution of the remaining silanol. Further treatment using hexamethyldisilazane (HMDS) results in the protection of the isolated remaining silanol groups by formation of ≡Si-O-SiMe3 and =Si(OSiMe3)2 but leaves ≡SiNH2 untouched. After reaction of this functionalized surface with ZrNp4, this latter displays mainly a bi-podal zirconium neopentyl organometallic complex [O-(=Si–NH)2Zr(IV)Np2] which has been fully characterized by diverse methods such as infrared transmission spectroscopy, magic angle spinning solid state nuclear magnetic resonance, surface elemental analysis, small angle X-ray powder diffraction (XRD), nitrogen adsorption and energy filtered transmission electron microscopy (EFTEM). These different characterization tools unambiguously prove that the zirconium organometallic complex reacts mostly with silylamine pairs to give a bi-podal zirconium bis-neopentyl complex, uniformly distributed into the channels of SBA-151000. Therefore this new material opens a new promising research area in Surface Organometallic Chemistry which, so far, was dealing mainly with O containing surface. It is expected that vicinal amine functions may play a very different role as compared with classical inorganic supports. Given the importance in the last decades of N containing ligands in catalysis, one may expect

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

    Directory of Open Access Journals (Sweden)

    Hardies Stephen C

    2007-02-01

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

  17. Immunocompatibility of Bacteriophages as Nanomedicines

    Directory of Open Access Journals (Sweden)

    Tranum Kaur

    2012-01-01

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

  18. The bacteriophage DNA packaging motor.

    Science.gov (United States)

    Rao, Venigalla B; Feiss, Michael

    2008-01-01

    An ATP-powered DNA translocation machine encapsidates the viral genome in the large dsDNA bacteriophages. The essential components include the empty shell, prohead, and the packaging enzyme, terminase. During translocation, terminase is docked on the prohead's portal protein. The translocation ATPase and the concatemer-cutting endonuclease reside in terminase. Remarkably, terminases, portal proteins, and shells of tailed bacteriophages and herpes viruses show conserved features. These DNA viruses may have descended from a common ancestor. Terminase's ATPase consists of a classic nucleotide binding fold, most closely resembling that of monomeric helicases. Intriguing models have been proposed for the mechanism of dsDNA translocation, invoking ATP hydrolysis-driven conformational changes of portal or terminase powering DNA motion. Single-molecule studies show that the packaging motor is fast and powerful. Recent advances permit experiments that can critically test the packaging models. The viral genome translocation mechanism is of general interest, given the parallels between terminases, helicases, and other motor proteins.

  19. Tumour biology: Herceptin acts as an anti-angiogenic cocktail

    Science.gov (United States)

    Izumi, Yotaro; Xu, Lei; di Tomaso, Emmanuelle; Fukumura, Dai; Jain, Rakesh K.

    2002-03-01

    Malignant tumours secrete factors that enable them to commandeer their own blood supply (angiogenesis), and blocking the action of these factors can inhibit tumour growth. But because tumours may become resistant to treatments that target individual angiogenic factors by switching over to other angiogenic molecules, a cocktail of multiple anti-angiogenic agents should be more effective. Here we show that herceptin, a monoclonal antibody against the cell-surface receptor HER2 (for human epidermal growth factor receptor-2; ref. 4), induces normalization and regression of the vasculature in an experimental human breast tumour that overexpresses HER2 in mice, and that it works by modulating the effects of different pro- and anti-angiogenic factors. As a single agent that acts against multiple targets, herceptin, or drugs like it, may offer a simple alternative to combination anti-angiogenic treatments.

  20. Recent advances of cocktail chemotherapy by combination drug delivery systems.

    Science.gov (United States)

    Hu, Quanyin; Sun, Wujin; Wang, Chao; Gu, Zhen

    2016-03-01

    Combination chemotherapy is widely exploited for enhanced cancer treatment in the clinic. However, the traditional cocktail administration of combination regimens often suffers from varying pharmacokinetics among different drugs. The emergence of nanotechnology offers an unparalleled opportunity for developing advanced combination drug delivery strategies with the ability to encapsulate various drugs simultaneously and unify the pharmacokinetics of each drug. This review surveys the most recent advances in combination delivery of multiple small molecule chemotherapeutics using nanocarriers. The mechanisms underlying combination chemotherapy, including the synergistic, additive and potentiation effects, are also discussed with typical examples. We further highlight the sequential and site-specific co-delivery strategies, which provide new guidelines for development of programmable combination drug delivery systems. Clinical outlook and challenges are also discussed in the end.

  1. Toxic cocktail: methanol poisoning in a tourist to Indonesia.

    Science.gov (United States)

    Gee, Paul; Martin, Elizabeth

    2012-08-01

    Methanol poisoning has become very uncommon in Australasia with regulations that have reduced its retail availability. This report describes a young tourist who developed sudden onset visual failure and rapid breathing 2 days after ingestion of a complimentary local drink called Arrack when travelling in Indonesia. She presented to a hospital in New Zealand with severe metabolic acidosis and a highly toxic methanol level at 17 mmol/L. The cocktail was consumed at a popular tourist bar but is likely to have been mixed from home-brewed or 'moonshine' alcohol tainted with methanol. The aetiology of methanol poisoning, its optic toxicology and therapeutic measures are discussed, as is the concerning number of methanol poisoning cases among tourists to Indonesia over recent years.

  2. The next generation of bacteriophage therapy.

    Science.gov (United States)

    Lu, Timothy K; Koeris, Michael S

    2011-10-01

    Bacteriophage therapy for bacterial infections is a concept with an extensive but controversial history. There has been a recent resurgence of interest into bacteriophages owing to the increasing incidence of antibiotic resistance and virulent bacterial pathogens. Despite these efforts, bacteriophage therapy remains an underutilized option in Western medicine due to challenges such as regulation, limited host range, bacterial resistance to phages, manufacturing, side effects of bacterial lysis, and delivery. Recent advances in biotechnology, bacterial diagnostics, macromolecule delivery, and synthetic biology may help to overcome these technical hurdles. These research efforts must be coupled with practical and rigorous approaches at academic, commercial, and regulatory levels in order to successfully advance bacteriophage therapy into clinical settings. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Cocoa fermentations conducted with a defined microbial cocktail inoculum.

    Science.gov (United States)

    Schwan, R F

    1998-04-01

    Cocoa fermentations were performed in wooden boxes under the following four experimental regimens: beans naturally fermented with wild microflora; aseptically prepared beans with no inoculum; and beans inoculated with a defined cocktail containing microorganisms at a suitable concentration either at zero time or by using phased additions at appropriate times. The cocktail used consisted of a yeast, Saccharomyces cerevisiae var. chevalieri, two lactic acid bacterial species, Lactobacillus lactis and Lactobacillus plantarum, and two acetic acid bacterial species, Acetobacter aceti and Gluconobacter oxydans subsp. suboxydans. The parameters measured were cell counts (for yeasts, filamentous fungi, lactic acid bacteria, acetic acid bacteria, and spore formers, including reisolation and identification of all residual cell types), sugar, ethanol, acetic acid, and lactic acid contents (and contents of other organic acids), pH, and temperature. A cut test for bean quality and a sensorial analysis of chocolate made from the beans were also performed. The natural fermentation mimicked exactly the conditions in 800-kg boxes on farms. The aseptic box remained largely free of microflora throughout the study, and no significant biochemical changes occurred. With the zero-time inoculum the fermentation was almost identical to the natural fermentation. The fermentation with the phased-addition inoculum was similar, but many changes in parameters were slower and less pronounced, which led to a slightly poorer end product. The data show that the nearly 50 common species of microorganisms found in natural fermentations can be replaced by a judicious selection and concentration of members of each physiological group. This is the first report of successful use of a defined, mixed starter culture in such a complex fermentation, and it should lead to chocolate of more reliable and better quality.

  4. Bacteriophages of Leuconostoc, Oenococcus, and Weissella

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  5. Bacteriophages of Leuconostoc, Oenococcus, and Weissella

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  6. Taking Bacteriophage Therapy Seriously: A Moral Argument

    OpenAIRE

    Gilbert Verbeken; Isabelle Huys; Jean-Paul Pirnay; Serge Jennes; Nina Chanishvili; Jacques Scheres; Andrzej Górski; Daniel De Vos; Carl Ceulemans

    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 practic...

  7. Taking Bacteriophage Therapy Seriously: A Moral Argument

    Directory of Open Access Journals (Sweden)

    Gilbert Verbeken

    2014-01-01

    Full Text Available 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.

  8. Taking bacteriophage therapy seriously: a moral argument.

    Science.gov (United States)

    Verbeken, Gilbert; Huys, Isabelle; Pirnay, Jean-Paul; Jennes, Serge; Chanishvili, Nina; Scheres, Jacques; Górski, Andrzej; De Vos, Daniel; Ceulemans, Carl

    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.

  9. Pathogen detection using engineered bacteriophages.

    Science.gov (United States)

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

    2012-04-01

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

  10. Bacteriophages for treating urinary tract infections in patients undergoing transurethral resection of the prostate: a randomized, placebo-controlled, double-blind clinical trial.

    Science.gov (United States)

    Leitner, Lorenz; Sybesma, Wilbert; Chanishvili, Nina; Goderdzishvili, Marina; Chkhotua, Archil; Ujmajuridze, Aleksandre; Schneider, Marc P; Sartori, Andrea; Mehnert, Ulrich; Bachmann, Lucas M; Kessler, Thomas M

    2017-09-26

    Urinary tract infections (UTI) are among the most prevalent microbial diseases and their financial burden on society is substantial. The continuing increase of antibiotic resistance worldwide is alarming. Thus, well-tolerated, highly effective therapeutic alternatives are urgently needed. Although there is evidence indicating that bacteriophage therapy may be effective and safe for treating UTIs, the number of investigated patients is low and there is a lack of randomized controlled trials. This study is the first randomized, placebo-controlled, double-blind trial investigating bacteriophages in UTI treatment. Patients planned for transurethral resection of the prostate are screened for UTIs and enrolled if in urine culture eligible microorganisms ≥10(4) colony forming units/mL are found. Patients are randomized in a double-blind fashion to the 3 study treatment arms in a 1:1:1 ratio to receive either: a) bacteriophage (i.e. commercially available Pyo bacteriophage) solution, b) placebo solution, or c) antibiotic treatment according to the antibiotic sensitivity pattern. All treatments are intended for 7 days. No antibiotic prophylaxes will be given to the double-blinded treatment arms a) and b). As common practice, the Pyo bacteriophage cocktail is subjected to periodic adaptation cycles during the study. Urinalysis, urine culture, bladder and pain diary, and IPSS questionnaire will be completed prior to and at the end of treatment (i.e. after 7 days) or at withdrawal/drop out from the study. Patients with persistent UTIs will undergo antibiotic treatment according to antibiotic sensitivity pattern. Based on the high lytic activity and the potential of resistance optimization by direct adaptation of bacteriophages, and considering the continuing increase of antibiotic resistance worldwide, bacteriophage therapy is a very promising treatment option for UTIs. Thus, our randomized controlled trial investigating bacteriophages for treating UTIs will provide

  11. The study of vial and cocktail for tritium radioactivity analysis of rain water by liquid scintillation counter

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Sung Jin; Kim, Hyo Jin; Kim, Hyun; Lee, Man Woo; Jeong, Dong Hyeok; Yang, Kwang Mo; Kang, Yeong Rok [Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan (Korea, Republic of); Nam, Sang Hee [Dept. of Biomedical Engineering, Inje University, Gimhae (Korea, Republic of)

    2015-10-15

    Even though the current method for tritium (3H) analysis is routine, for the case of the low level of tritium in the environment, special conditions have to be fulfilled in order to obtain accurate and reliable tritium measurements. There are very little comparative data concerning commercial scintillating cocktails. The best cocktails for measuring tritium are those based on benzene derived solvent, and the worse cocktails are those which have complex chemical composition or contain too small concentration of scintillators. The aim of study was to investigate various vials and cocktails by comparison with the combination of few different scintillation cocktails and vials in our routine measurements according to count, efficiency, and the figure of merit (FOM). The comparison of three types of vials with scintillation cocktails for tritium activity analysis of rain water shows that glass vials have higher count rates and HiSafe 3 cocktails have lower FOM.

  12. [Research advance on bacteriophage therapy in bacterial infection].

    Science.gov (United States)

    Pei, Jingliang; Fu, Yurong

    2013-11-01

    Bacteriophage is a bacterium dependent virus. It has unique advantages in the treatment of bacterial infection, especially infection caused by drug-resistant bacteria. Its metabolic kinetics and route of administration are the current research focus. Bacteriophage lytic enzyme, as a new therapeutic method, has more advantages than active bacteriophage. This review is focused on the recent progress in bacteriophage research, including the mechanism of bacteria lysis, the route of administration, the application of genetic engineering, etc.

  13. Enhanced antimicrobial activity of peptide‐cocktails against common bacterial contaminants of ex vivo stored platelets

    National Research Council Canada - National Science Library

    Mohan, K. V. K; Rao, S. Sainath; Gao, Y; Atreya, C. D; Grobusch, M

    2014-01-01

    .... In the present study, we selected PD 3, PD 4, RW 2, RW 3 and RW 4 and evaluated each individual peptide and their various combinations to see whether the cocktail regimen enhances the antimicrobial...

  14. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Science.gov (United States)

    2010-04-01

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

  15. A cytochrome P450 phenotyping cocktail causing unexpected adverse reactions in female volunteers

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Steen; Damkier, Per; Hougaard Christensen, Mette Marie

    2013-01-01

    A four-drug cytochrome P450 (CYP) phenotyping cocktail was developed to rapidly and safely determine CYP2D6, CYP2C19, CYP2C9 and CYP1A2 enzyme activity and phenotype.......A four-drug cytochrome P450 (CYP) phenotyping cocktail was developed to rapidly and safely determine CYP2D6, CYP2C19, CYP2C9 and CYP1A2 enzyme activity and phenotype....

  16. Characterization of Temperate Bacteriophages of Bacillus subtilis by the Restriction Endonuclease EcoRI: Evidence for Three Different Temperate Bacteriophages

    Science.gov (United States)

    Wilson, G. A.; Williams, M. T.; Baney, H. W.; Young, F. E.

    1974-01-01

    Temperate bacteriophages of Bacillus subtilis were characterized according to host range and digestion of the bacteriophage genome by endonuclease EcoRI. The three bacteriophages, φ3T, SPO2, and φ105, were all heteroimmune, and the DNA digests showed dissimilar patterns by agarose-ethidium bromide gel electrophoresis. Images PMID:4213607

  17. Complexity of Cocktail Party Graph and Crown Graph

    Directory of Open Access Journals (Sweden)

    S. N. Daoud

    2012-01-01

    Full Text Available Problem statement: The number of spanning trees τ(G in graphs (networks was an important invariant. Approach: Using the properties of the Chebyshev polynomials of the second kind and the linear algebra techniques to evaluate the associated determinants. Results: The complexity, number of spanning trees, of the cocktail party graph on 2n vertices, given in detail in the text was proved. Also the complexity of the crown graph on 2n vertices was shown to had the value nn-2 (n-1 (n-2n-1. Conclusion: The number of spanning trees τ(G in graphs (networks is an important invariant. The evaluation of this number and analyzing its behavior is not only interesting from a mathematical (computational perspective, but also, it is an important measure of reliability of a network and designing electrical circuits. Some computationally hard problems such as the travelling salesman problem can be solved approximately by using spanning trees. Due to the high dependence of the network design and reliability on the graph theory we introduced the above important theorems and lemmas and their proofs.

  18. How does spatial hearing affect cocktail party conversations?

    Science.gov (United States)

    Shinn-Cunningham, Barbara G.

    2003-04-01

    Although spatial cues are not a dominant factor in auditory scene analysis by humans, spatial separation of a target talker and an interfering sound source often increases the intelligibility of the target. A large portion of this improvement arises from a simple acoustic effect: separating the target and interferer generally increases the target-to-interferer energy ratio at one ear. When the target is near threshold, binaural processing provides an additional small, but important improvement. Finally, in conditions where both target and interferer are audible but are difficult to segregate, spatial separation can improve the ability to stream the sources and interpret the target message. The echoes and reverberation present in everyday environments influence all of these factors, altering the target-to-interferer energy ratio, the effectiveness of binaural processing, and the ability to stream the sources. A number of studies will be reviewed to demonstrate how these different factors influence speech intelligibility and affect cocktail party conversations in everyday environments. [Work supported by the Air Force Office of Scientific Research and the Alfred P. Sloan Foundation.

  19. Biocontrol and Rapid Detection of Food-Borne Pathogens Using Bacteriophages and Endolysins.

    Science.gov (United States)

    Bai, Jaewoo; Kim, You-Tae; Ryu, Sangryeol; Lee, Ju-Hoon

    2016-01-01

    Bacteriophages have been suggested as natural food preservatives as well as rapid detection materials for food-borne pathogens in various foods. Since Listeria monocytogenes-targeting phage cocktail (ListShield) was approved for applications in foods, numerous phages have been screened and experimentally characterized for phage applications in foods. A single phage and phage cocktail treatments to various foods contaminated with food-borne pathogens including E. coli O157:H7, Salmonella enterica, Campylobacter jejuni, Listeria monocytogenes, Staphylococcus aureus, Cronobacter sakazakii, and Vibrio spp. revealed that they have great potential to control various food-borne pathogens and may be alternative for conventional food preservatives. In addition, phage-derived endolysins with high host specificity and host lysis activities may be preferred to food applications rather than phages. For rapid detection of food-borne pathogens, cell-wall binding domains (CBDs) from endolysins have been suggested due to their high host-specific binding. Fluorescence-tagged CBDs have been successfully evaluated and suggested to be alternative materials of expensive antibodies for various detection applications. Most recently, reporter phage systems have been developed and tested to confirm their usability and accuracy for specific detection. These systems revealed some advantages like rapid detection of only viable pathogenic cells without interference by food components in a very short reaction time, suggesting that these systems may be suitable for monitoring of pathogens in foods. Consequently, phage is the next-generation biocontrol agent as well as rapid detection tool to confirm and even identify the food-borne pathogens present in various foods.

  20. Biocontrol and Rapid Detection of Food-borne Pathogens Using Bacteriophages and Endolysins

    Directory of Open Access Journals (Sweden)

    Jaewoo eBai

    2016-04-01

    Full Text Available Bacteriophages have been suggested as natural food preservatives as well as rapid detection materials for food-borne pathogens in various foods. Since Listeria monocytogenes-targeting phage cocktail (ListShield was approved for applications in foods, numerous phages have been screened and experimentally characterized for phage applications in foods. A single phage and phage cocktail treatments to various foods contaminated with food-borne pathogens including E. coli O157:H7, Salmonella enterica, Campylobacter jejuni, Listeria monocytogenes, Staphylococcus aureus, Cronobacter sakazakii, and Vibrio spp. revealed that they have great potential to control various food-borne pathogens and may be alternative for conventional food preservatives. In addition, phage-derived endolysins with high host specificity and host lysis activities may be preferred to food applications rather than phages. For rapid detection of food-borne pathogens, cell-wall binding domains (CBDs from endolysins have been suggested due to their high host-specific binding. Fluorescence-tagged CBDs have been successfully evaluated and suggested to be alternative materials of expensive antibodies for various detection applications. Most recently, reporter phage systems have been developed and tested to confirm their usability and accuracy for specific detection. These systems revealed some advantages like rapid detection of only viable pathogenic cells without interference by food components in a very short reaction time, suggesting that these systems may be suitable for monitoring of pathogens in foods. Consequently, phage is the next-generation biocontrol agent as well as rapid detection tool to confirm and even identify the food-borne pathogens present in various foods.

  1. Bacteriophage-Based Pathogen Detection

    Science.gov (United States)

    Ripp, Steven

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

  2. Photodynamic inactivation of mammalian viruses and bacteriophages.

    Science.gov (United States)

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

    2012-07-01

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

  3. Photodynamic Inactivation of Mammalian Viruses and Bacteriophages

    Directory of Open Access Journals (Sweden)

    Liliana Costa

    2012-06-01

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

  4. Photodynamic Inactivation of Mammalian Viruses and Bacteriophages

    Science.gov (United States)

    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

  5. The efficacy of sewage influent-isolated bacteriophages on Pseudomonas aeruginosa in a mixed-species biofilm

    KAUST Repository

    Yap, Scott

    2016-12-01

    The growth of environmentally persistent biofilms in cooling towers causes several associated problems, including microbiologically-induced corrosion (MIC) and biofouling. Current chemical control methods are not only ineffective against biofilms and costly to procure, they also have downstream environmental impacts when released untreated, or incur additional treatment costs. Bacteriophages are alternative biofilm control agents that have the potential to be more effective, cheaper to produce and yet have a more benign effect on the environment. In this study, biofilms grown under conditions simulating seawater fed cooling towers were characterized and the differences in growth and community make-up across time and different substrates were assessed. An MIC associated bacterium common in cooling tower water, P. aeruginosa, was chosen. Seven bacteriophage strains found to be effective against the chosen bacterium were isolated from wastewater influent. The relative effectiveness of these strains was measured against P. aeruginosa across different salinities. Separate biofilms fed with P. aeruginosa enriched seawater were characterized and the effectiveness of the isolated strains, singly and in cocktails, against the enriched biofilms was measured.

  6. Antiviral effect of cationic compounds on bacteriophages

    Directory of Open Access Journals (Sweden)

    Mai Huong eChatain-Ly

    2013-03-01

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

  7. Bacteriophages safely reduce Salmonella contamination in pet food and raw pet food ingredients.

    Science.gov (United States)

    Soffer, Nitzan; Abuladze, Tamar; Woolston, Joelle; Li, Manrong; Hanna, Leigh Farris; Heyse, Serena; Charbonneau, Duane; Sulakvelidze, Alexander

    2016-01-01

    Contamination of pet food with Salmonella is a serious public health concern, and several disease outbreaks have recently occurred due to human exposure to Salmonella tainted pet food. The problem is especially challenging for raw pet foods (which include raw meats, seafood, fruits, and vegetables). These foods are becoming increasingly popular because of their nutritional qualities, but they are also more difficult to maintain Salmonella-free because they lack heat-treatment. Among various methods examined to improve the safety of pet foods (including raw pet food), one intriguing approach is to use bacteriophages to specifically kill Salmonella serotypes. At least 2 phage preparations (SalmoFresh® and Salmonelex™) targeting Salmonella are already FDA cleared for commercial applications to improve the safety of human foods. However, similar preparations are not yet available for pet food applications. Here, we report the results of evaluating one such preparation (SalmoLyse®) in reducing Salmonella levels in various raw pet food ingredients (chicken, tuna, turkey, cantaloupe, and lettuce). Application of SalmoLyse® in low (ca. 2-4×10(6) PFU/g) and standard (ca. 9×10(6) PFU/g) concentrations significantly (P foods examined compared to control treatments. When SalmoLyse®-treated (ca. 2×10(7) PFU/g) dry pet food was fed to cats and dogs, it did not trigger any deleterious side effects in the pets. Our data suggest that the bacteriophage cocktail lytic for Salmonella can significantly and safely reduce Salmonella contamination in various raw pet food ingredients.

  8. Novel microRNA prosurvival cocktail for improving engraftment and function of cardiac progenitor cell transplantation.

    Science.gov (United States)

    Hu, Shijun; Huang, Mei; Nguyen, Patricia K; Gong, Yongquan; Li, Zongjin; Jia, Fangjun; Lan, Feng; Liu, Junwei; Nag, Divya; Robbins, Robert C; Wu, Joseph C

    2011-09-13

    Although stem cell therapy has provided a promising treatment for myocardial infarction, the low survival of the transplanted cells in the infarcted myocardium is possibly a primary reason for failure of long-term improvement. Therefore, the development of novel prosurvival strategies to boost stem cell survival will be of significant benefit to this field. Cardiac progenitor cells (CPCs) were isolated from transgenic mice, which constitutively express firefly luciferase and green fluorescent protein. The CPCs were transduced with individual lentivirus carrying the precursor of miR-21, miR-24, and miR-221, a cocktail of these 3 microRNA precursors, or green fluorescent protein as a control. After challenge in serum free medium, CPCs treated with the 3 microRNA cocktail showed significantly higher viability compared with untreated CPCs. After intramuscular and intramyocardial injections, in vivo bioluminescence imaging showed that microRNA cocktail-treated CPCs survived significantly longer after transplantation. After left anterior descending artery ligation, microRNA cocktail-treated CPCs boost the therapeutic efficacy in terms of functional recovery. Histological analysis confirmed increased myocardial wall thickness and CPC engraftment in the myocardium with the microRNA cocktail. Finally, we used bioinformatics analysis and experimental validation assays to show that Bim, a critical apoptotic activator, is an important target gene of the microRNA cocktail, which collectively can bind to the 3'UTR region of Bim and suppress its expression. We have demonstrated that a microRNA prosurvival cocktail (miR-21, miR-24, and miR-221) can improve the engraftment of transplanted cardiac progenitor cells and therapeutic efficacy for treatment of ischemic heart disease.

  9. Cocktail sedation containing propofol versus conventional sedation for ERCP: a prospective, randomized controlled study

    Directory of Open Access Journals (Sweden)

    Angsuwatcharakon Phonthep

    2012-08-01

    Full Text Available Abstract Background ERCP practically requires moderate to deep sedation controlled by a combination of benzodiazepine and opiod. Propofol as a sole agent may cause oversedation. A combination (cocktail of infused propofol, meperidine, and midazolam can reduce the dosage of propofol and we hypothesized that it might decrease the risk of oversedation. We prospectively compare the efficacy, recovery time, patient satisfactory, and side effects between cocktail and conventional sedations in patients undergoing ERCP. Methods ERCP patients were randomized into 2 groups; the cocktail group (n = 103 and the controls (n = 102. For induction, a combination of 25 mg of meperidine and 2.5 mg of midazolam were administered in both groups. In the cocktail group, a bolus dose of propofol 1 mg/kg was administered and continuously infused. In the controls, 25 mg of meperidine or 2.5 mg/kg of midazolam were titrated to maintain the level of sedation. Results In the cocktail group, the average administration rate of propofol was 6.2 mg/kg/hr. In the control group; average weight base dosage of meperidine and midazolam were 1.03 mg/kg and 0.12 mg/kg, respectively. Recovery times and patients’ satisfaction scores in the cocktail and control groups were 9.67 minutes and 12.89 minutes (P = 0.045, 93.1and 87.6 (P P Conclusions Cocktail sedation containing propofol provides faster recovery time and better patients’ satisfaction for patients undergoing ERCP. However, mild degree of desaturation may still develop. Trial registration ClinicalTrials.gov, NCT01540084

  10. Effects of polar bear and killer whale derived contaminant cocktails on marine mammal immunity.

    Science.gov (United States)

    Desforges, Jean-Pierre; Levin, Milton; Jasperse, Lindsay; De Guise, Sylvain; Eulaers, Igor; Letcher, Robert J; Acquarone, Mario; Nordoy, Erling; Folkow, Lars; Hammer Jensen, Trine; Grondahl, Carsten; Bertelsen, Mads F; St Leger, Judy; Almunia, Javier; Sonne, Christian; Dietz, Rune

    2017-09-06

    Most controlled toxicity studies use single chemical exposures that do not represent the real world situation of complex mixtures of known and unknown natural and anthropogenic substances. In the present study, complex contaminant cocktails derived from the blubber of polar bears (PB; Ursus maritimus) and killer whales (KW; Orcinus orca) were used for in vitro concentration-response experiments with PB, cetacean and seal spp. immune cells to evaluate the effect of realistic contaminant mixtures on various immune functions. Cytotoxic effects of the PB cocktail occurred at lower concentrations than the KW cocktail (1 vs 16 µg/ml), likely due to differences in contaminant profiles in the mixtures derived from the adipose of each species. Similarly, significant reduction of lymphocyte proliferation occured at much lower exposures in the PB cocktail (EC50: 0.94 vs 6.06 µg/ml; P < 0.01), while the KW cocktail caused a much faster decline in proliferation (slope: 2.9 vs 1.7; P = 0.04). Only the KW cocktail modulated natural killer (NK) cell activity and neutrophil and monocyte phagocytosis in a concentration- and species-dependent manner. No clear sensitivity differences emerged when comparing cetaceans, seals and PB. Our results showing lower effect levels for complex mixtures relative to single compounds suggest that previous risk assessments underestimate the effects of real world contaminant exposure on immunity. Our results using blubber-derived contaminant cocktails add realism to in vitro exposure experiments and confirm the immunotoxic risk marine mammals face from exposure to complex mixtures of environmental contaminants.

  11. Synthesis of Well-Defined Copper "N"-Heterocyclic Carbene Complexes and Their Use as Catalysts for a "Click Reaction": A Multistep Experiment that Emphasizes the Role of Catalysis in Green Chemistry

    Science.gov (United States)

    Ison, Elon A.; Ison, Ana

    2012-01-01

    A multistep experiment for an advanced synthesis lab course that incorporates topics in organic-inorganic synthesis and catalysis and highlights green chemistry principles was developed. Students synthesized two "N"-heterocyclic carbene ligands, used them to prepare two well-defined copper(I) complexes and subsequently utilized the complexes as…

  12. Development of the first well-defined tungsten oxo alkyl derivatives supported on silica by SOMC: towards a model of WO3/SiO2 olefin metathesis catalyst

    KAUST Repository

    Mazoyer, Etienne

    2010-01-01

    A well-defined, silica-supported tungsten oxo alkyl species prepared by the surface organometallic chemistry approach displays high and sustained activity in propene metathesis. Remarkably, its catalytic performances outpace those of the parent imido derivative, underlining the importance of the oxo ligand in the design of robust catalysts. © 2010 The Royal Society of Chemistry.

  13. Synthesis of Well-Defined Copper "N"-Heterocyclic Carbene Complexes and Their Use as Catalysts for a "Click Reaction": A Multistep Experiment that Emphasizes the Role of Catalysis in Green Chemistry

    Science.gov (United States)

    Ison, Elon A.; Ison, Ana

    2012-01-01

    A multistep experiment for an advanced synthesis lab course that incorporates topics in organic-inorganic synthesis and catalysis and highlights green chemistry principles was developed. Students synthesized two "N"-heterocyclic carbene ligands, used them to prepare two well-defined copper(I) complexes and subsequently utilized the complexes as…

  14. Synthesis of novel well-defined poly(vinyl acetate)-b-poly(acrylonitrile) and derivatized water-soluble poly(vinyl alcohol)-b-poly(acrylic acid) block copolymers by cobalt-mediated radical polymerization

    NARCIS (Netherlands)

    Debuigne, A.; Warnant, J.; Jerome, R.; Voets, I.K.; Keizer, de A.; Cohen Stuart, M.A.; Detrembleur, C.

    2008-01-01

    Poly(vinyl acetate)¿Co(acac)2 macroinitiators, prepared by cobalt-mediated radical polymerization of vinyl acetate (VAc), were used to synthesize well-defined poly(vinyl acetate)-b-poly(acrylonitrile) (PVAc-b-PAN) block copolymers. Different solvents and temperatures were tested for the polymerizati

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

    Science.gov (United States)

    Gong, Chao; Jiang, Xiuping

    2015-08-01

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

  16. Becker nevus with vitiligo and lichen planus: Cocktail of dermatoses

    Directory of Open Access Journals (Sweden)

    Sanjeev Gupta

    2010-07-01

    Full Text Available Context: Becker nevus has been reported to be associated with lichen planus (LP in isolated case reports in past. The association of LP and vitiligo has been noted in few cases and has been attributed to a common autoimmune etiology. The coexistence of lichen planus, vitiligo and Becker nevus has not been reported so far. Case Report: A thirty five years old male presented with lesions of Becker nevus along with vitiligo and Lichen planus coexisting at one place on right side of the chest. Vitiligo and Becker nevus could not be treated. Lichen planus was confirmed histopathologically. We were able to treat lichen planus with topical potent steroids, tacrolimus and systemic antihistamines. The vitiligo lesion in our case was resistant to treatment. Conclusion: This case is being reported for the rare occurrence of three different well defined skin conditions in our patient and reviews the possible known etiological factors for their coexistence.

  17. The bacteriophage DNA packaging machine.

    Science.gov (United States)

    Feiss, Michael; Rao, Venigalla B

    2012-01-01

    Large dsDNA bacteriophages and herpesviruses encode a powerful ATP-driven DNA-translocating machine that encapsidates a viral genome into a preformed capsid shell or prohead. The key components of the packaging machine are the packaging enzyme (terminase, motor) and the portal protein that forms the unique DNA entrance vertex of prohead. The terminase complex, comprised of a recognition subunit (small terminase) and an endonuclease/translocase subunit (large terminase), cuts viral genome concatemers. The terminase-viral DNA complex docks on the portal vertex, assembling a motor complex containing five large terminase subunits. The pentameric motor processively translocates DNA until the head shell is full with one viral genome. The motor cuts the DNA again and dissociates from the full head, allowing head-finishing proteins to assemble on the portal, sealing the portal, and constructing a platform for tail attachment. A body of evidence from molecular genetics and biochemical, structural, and biophysical approaches suggests that ATP hydrolysis-driven conformational changes in the packaging motor (large terminase) power DNA motion. Various parts of the motor subunit, such as the ATPase, arginine finger, transmission domain, hinge, and DNA groove, work in concert to translocate about 2 bp of DNA per ATP hydrolyzed. Powerful single-molecule approaches are providing precise delineation of steps during each translocation event in a motor that has a speed as high as a millisecond/step. The phage packaging machine has emerged as an excellent model for understanding the molecular machines, given the mechanistic parallels between terminases, helicases, and numerous motor proteins.

  18. Toward modern inhalational bacteriophage therapy: nebulization of bacteriophages of Burkholderia cepacia complex.

    Science.gov (United States)

    Golshahi, Laleh; Seed, Kimberley D; Dennis, Jonathan J; Finlay, Warren H

    2008-12-01

    Antibiotic-resistant bacterial infections have renewed interest in finding substitute methods of treatment. The purpose of the present in vitro study was to investigate the possibility of respiratory delivery of a Burkholderia cepacia complex (BCC) bacteriophage by nebulized aerosol administration. Bacteriophages in isotonic saline were aerosolized with Pari LC star and eFlow nebulizers, at titers with mean value (standard deviation) of 2.15 x 10(8) (1.63 x 10(8)) plaque-forming unit (PFU)/mL in 2.5-mL nebulizer fills. The breathing pattern of an adult was simulated using a pulmonary waveform generator. During breath simulation, the size distributions of the nebulized aerosol were measured using phase doppler anemometry (PDA). Efficiency of nebulizer delivery was subsequently determined by collection of aerosol on low resistance filters and measurement of bacteriophage titers. These filter titers were used as input data to a mathematical lung deposition model to predict regional deposition of bacteriophages in the lung and initial bacteriophage titers in the liquid surface layer of each conducting airway generation. The results suggest that BCC bacteriophages can be nebulized successfully within a reasonable delivery time and predicted titers in the lung indicate that this method may hold potential for treatment of bacterial lung infections common among cystic fibrosis patients.

  19. A stochastic model for bacteriophage therapies

    CERN Document Server

    Bardina, Xavier; Rovira, Carles; Tindel, Samy

    2011-01-01

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

  20. Bacteriophages as surface and ground water tracers

    Directory of Open Access Journals (Sweden)

    P. Rossi

    1998-01-01

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

  1. ADSORPTION OF BACTERIOPHAGES ON CLAY MINERALS

    Science.gov (United States)

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

  2. Bacteriophages as surface and ground water tracers

    Science.gov (United States)

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

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

  3. ADSORPTION OF BACTERIOPHAGES ON CLAY MINERALS

    Science.gov (United States)

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

  4. Comparative genomics of Shiga toxin encoding bacteriophages

    Directory of Open Access Journals (Sweden)

    Smith Darren L

    2012-07-01

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

  5. An Undergraduate Laboratory Activity Demonstrating Bacteriophage Specificity

    Directory of Open Access Journals (Sweden)

    Mary E. Allen

    2013-02-01

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

  6. Evaluation of Cocktails with Recombinant Proteins of Mycobacterium bovis for a Specific Diagnosis of Bovine Tuberculosis

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    María Laura Mon

    2014-01-01

    Full Text Available The Delayed type hypersensitivity skin test (DTH and interferon-gamma assay are used for the diagnosis of bovine tuberculosis (TBB. The specificity of these diagnoses, however, is compromised because both are based on the response against purified protein derivative of Mycobacterium bovis (PPD-B. In this study, we assessed the potential of two cocktails containing M. bovis recombinant proteins: cocktail 1 (C1: ESAT-6, CFP-10 and MPB83 and cocktail 2 (C2: ESAT-6, CFP-10, MPB83, HspX, TB10.3, and MPB70. C1, C2, and PPD-B showed similar response by DTH in M. bovis-sensitized guinea pigs. Importantly, C1 induced a lower response than PPD-B in M. avium-sensitized guinea pigs. In cattle, C1 displayed better performance than PPD-B and C2; indeed, C1 showed the least detection of animals either vaccinated or Map-infected. To optimize the composition of the cocktails, we obtained protein fractions from PPD-B and tested their immunogenicity in experimentally M. bovis-infected cattle. In one highly reactive fraction, seven proteins were identified. The inclusion of FixB in C1 enhanced the recognition of M. bovis-infected cattle without compromising specificity. Our data provide a promising basis for the future development of a cocktail for TBB detection without interference by the presence of sensitized or infected animals with other mycobacteria.

  7. Evaluation of Cocktails with Recombinant Proteins of Mycobacterium bovis for a Specific Diagnosis of Bovine Tuberculosis

    Science.gov (United States)

    Mon, María Laura; Moyano, Roberto Damián; Viale, Mariana Noelia; Colombatti Olivieri, María Alejandra; Gamietea, Ignacio José; Montenegro, Valeria Noely; Alonso, Bernardo; Santangelo, María de la Paz; Singh, Mahavir; Duran, Rosario; Romano, María Isabel

    2014-01-01

    The Delayed type hypersensitivity skin test (DTH) and interferon-gamma assay are used for the diagnosis of bovine tuberculosis (TBB). The specificity of these diagnoses, however, is compromised because both are based on the response against purified protein derivative of Mycobacterium bovis (PPD-B). In this study, we assessed the potential of two cocktails containing M. bovis recombinant proteins: cocktail 1 (C1): ESAT-6, CFP-10 and MPB83 and cocktail 2 (C2): ESAT-6, CFP-10, MPB83, HspX, TB10.3, and MPB70. C1, C2, and PPD-B showed similar response by DTH in M. bovis-sensitized guinea pigs. Importantly, C1 induced a lower response than PPD-B in M. avium-sensitized guinea pigs. In cattle, C1 displayed better performance than PPD-B and C2; indeed, C1 showed the least detection of animals either vaccinated or Map-infected. To optimize the composition of the cocktails, we obtained protein fractions from PPD-B and tested their immunogenicity in experimentally M. bovis-infected cattle. In one highly reactive fraction, seven proteins were identified. The inclusion of FixB in C1 enhanced the recognition of M. bovis-infected cattle without compromising specificity. Our data provide a promising basis for the future development of a cocktail for TBB detection without interference by the presence of sensitized or infected animals with other mycobacteria. PMID:25110654

  8. Monosaccharides and Ethanol Production from Superfine Ground Sugarcane Bagasse Using Enzyme Cocktail

    Directory of Open Access Journals (Sweden)

    Jingbo Li

    2014-03-01

    Full Text Available In this work, the effect of particle size on the enzymatic hydrolysis of milled and sieved sugarcane bagasse (SCB was studied. The enzymatic hydrolysis and fermentability of superfine ground SCB (SGP400 using an enzyme cocktail strategy were also explored. Particle size reduction improved the enzymatic hydrolysis. The highest glucose yield was 44.75%, which was obtained from SGP400. The enzyme cocktail strategy greatly enhanced the glucose and xylose yield. The maximum glucose and xylose yield was from the enzyme cocktail of cellulase, xylanase, and pectinase. Synergistic action between xylanase and pectinase as well as cellulase and pectinase was quite noticeable. Hydrolysis times affected the degree of synergism. Ethanol production was carried out by employing simultaneous saccharification and fermentation (SSF and semi-SSF using enzymes and their cocktails. Semi-SSF was found to be the better one compared with SSF. Xylanase and pectinase aided the ethanol production in both fermentation modes. Ethanol yield was 7.81 and 7.30 g/L for semi-SSF and SSF, respectively by using an enzyme cocktail of cellulase, β-glucosidase, pectinase, and xylanase.

  9. A thermophilic ionic liquid-tolerant cellulase cocktail for the production of cellulosic biofuels.

    Directory of Open Access Journals (Sweden)

    Joshua I Park

    Full Text Available Generation of biofuels from sugars in lignocellulosic biomass is a promising alternative to liquid fossil fuels, but efficient and inexpensive bioprocessing configurations must be developed to make this technology commercially viable. One of the major barriers to commercialization is the recalcitrance of plant cell wall polysaccharides to enzymatic hydrolysis. Biomass pretreatment with ionic liquids (ILs enables efficient saccharification of biomass, but residual ILs inhibit both saccharification and microbial fuel production, requiring extensive washing after IL pretreatment. Pretreatment itself can also produce biomass-derived inhibitory compounds that reduce microbial fuel production. Therefore, there are multiple points in the process from biomass to biofuel production that must be interrogated and optimized to maximize fuel production. Here, we report the development of an IL-tolerant cellulase cocktail by combining thermophilic bacterial glycoside hydrolases produced by a mixed consortia with recombinant glycoside hydrolases. This enzymatic cocktail saccharifies IL-pretreated biomass at higher temperatures and in the presence of much higher IL concentrations than commercial fungal cocktails. Sugars obtained from saccharification of IL-pretreated switchgrass using this cocktail can be converted into biodiesel (fatty acid ethyl-esters or FAEEs by a metabolically engineered strain of E. coli. During these studies, we found that this biodiesel-producing E. coli strain was sensitive to ILs and inhibitors released by saccharification. This cocktail will enable the development of novel biomass to biofuel bioprocessing configurations that may overcome some of the barriers to production of inexpensive cellulosic biofuels.

  10. Efficiency Enhancement of Cocktail Dye of Ixora coccinea and Tradescantia spathacea in DSSC.

    Science.gov (United States)

    Zolkepli, Zularif; Lim, Andery; Ekanayake, Piyasiri; Tennakoon, Kushan

    2015-01-01

    The use of anthocyanin dyes extracted from epidermal leaves of Tradescantia spathacea (Trant) and petals of Ixora coccinea (IX) was evaluated in the application of dye-sensitized solar cells (DSSCs). Subsequently, cocktail anthocyanin dyes from these dyes were prepared and how they enhanced the cell's overall performance was assessed using five different volume-to-volume ratios. Cocktail dyes absorbed a wider range of light in the visible region, thus increasing the cell efficiencies of the cocktail dyes when compared to the DSSC sensitized by individual dyes. The surface charge (zeta-potential), average size of aggregated anthocyanin molecules (zetasizer), and anthocyanin stability in different storage temperatures were analyzed and recorded. Lower size of aggregated dye molecules as revealed from the cocktail dyes ensured better adsorption onto the TiO2 film. Tradescantia/Ixora pigments mixed in 1 : 4 ratio showed the highest cell efficiency of η = 0.80%, under the irradiance of 100 mW cm(-2), with a short-circuit current density 4.185 mA/cm(2), open-circuit voltage of 0.346 V, and fill factor of 0.499. It was found that the desired storage temperature for these cocktail dyes to be stable over time was -20°C, in which the anthocyanin half-life was about approximately 1727 days.

  11. Efficiency Enhancement of Cocktail Dye of Ixora coccinea and Tradescantia spathacea in DSSC

    Directory of Open Access Journals (Sweden)

    Zularif Zolkepli

    2015-01-01

    Full Text Available The use of anthocyanin dyes extracted from epidermal leaves of Tradescantia spathacea (Trant and petals of Ixora coccinea (IX was evaluated in the application of dye-sensitized solar cells (DSSCs. Subsequently, cocktail anthocyanin dyes from these dyes were prepared and how they enhanced the cell’s overall performance was assessed using five different volume-to-volume ratios. Cocktail dyes absorbed a wider range of light in the visible region, thus increasing the cell efficiencies of the cocktail dyes when compared to the DSSC sensitized by individual dyes. The surface charge (zeta-potential, average size of aggregated anthocyanin molecules (zetasizer, and anthocyanin stability in different storage temperatures were analyzed and recorded. Lower size of aggregated dye molecules as revealed from the cocktail dyes ensured better adsorption onto the TiO2 film. Tradescantia/Ixora pigments mixed in 1 : 4 ratio showed the highest cell efficiency of η=0.80%, under the irradiance of 100 mW cm−2, with a short-circuit current density 4.185 mA/cm2, open-circuit voltage of 0.346 V, and fill factor of 0.499. It was found that the desired storage temperature for these cocktail dyes to be stable over time was −20°C, in which the anthocyanin half-life was about approximately 1727 days.

  12. A Thermophilic Ionic Liquid-Tolerant Cellulase Cocktail for the Production of Cellulosic Biofuels

    Science.gov (United States)

    Park, Joshua I.; Steen, Eric J.; Burd, Helcio; Evans, Sophia S.; Redding-Johnson, Alyssa M.; Batth, Tanveer; Benke, Peter I.; D'haeseleer, Patrik; Sun, Ning; Sale, Kenneth L.; Keasling, Jay D.; Lee, Taek Soon; Petzold, Christopher J.; Mukhopadhyay, Aindrila; Singer, Steven W.; Simmons, Blake A.; Gladden, John M.

    2012-01-01

    Generation of biofuels from sugars in lignocellulosic biomass is a promising alternative to liquid fossil fuels, but efficient and inexpensive bioprocessing configurations must be developed to make this technology commercially viable. One of the major barriers to commercialization is the recalcitrance of plant cell wall polysaccharides to enzymatic hydrolysis. Biomass pretreatment with ionic liquids (ILs) enables efficient saccharification of biomass, but residual ILs inhibit both saccharification and microbial fuel production, requiring extensive washing after IL pretreatment. Pretreatment itself can also produce biomass-derived inhibitory compounds that reduce microbial fuel production. Therefore, there are multiple points in the process from biomass to biofuel production that must be interrogated and optimized to maximize fuel production. Here, we report the development of an IL-tolerant cellulase cocktail by combining thermophilic bacterial glycoside hydrolases produced by a mixed consortia with recombinant glycoside hydrolases. This enzymatic cocktail saccharifies IL-pretreated biomass at higher temperatures and in the presence of much higher IL concentrations than commercial fungal cocktails. Sugars obtained from saccharification of IL-pretreated switchgrass using this cocktail can be converted into biodiesel (fatty acid ethyl-esters or FAEEs) by a metabolically engineered strain of E. coli. During these studies, we found that this biodiesel-producing E. coli strain was sensitive to ILs and inhibitors released by saccharification. This cocktail will enable the development of novel biomass to biofuel bioprocessing configurations that may overcome some of the barriers to production of inexpensive cellulosic biofuels. PMID:22649505

  13. A thermophilic ionic liquid-tolerant cellulase cocktail for the production of cellulosic biofuels.

    Science.gov (United States)

    Park, Joshua I; Steen, Eric J; Burd, Helcio; Evans, Sophia S; Redding-Johnson, Alyssa M; Batth, Tanveer; Benke, Peter I; D'haeseleer, Patrik; Sun, Ning; Sale, Kenneth L; Keasling, Jay D; Lee, Taek Soon; Petzold, Christopher J; Mukhopadhyay, Aindrila; Singer, Steven W; Simmons, Blake A; Gladden, John M

    2012-01-01

    Generation of biofuels from sugars in lignocellulosic biomass is a promising alternative to liquid fossil fuels, but efficient and inexpensive bioprocessing configurations must be developed to make this technology commercially viable. One of the major barriers to commercialization is the recalcitrance of plant cell wall polysaccharides to enzymatic hydrolysis. Biomass pretreatment with ionic liquids (ILs) enables efficient saccharification of biomass, but residual ILs inhibit both saccharification and microbial fuel production, requiring extensive washing after IL pretreatment. Pretreatment itself can also produce biomass-derived inhibitory compounds that reduce microbial fuel production. Therefore, there are multiple points in the process from biomass to biofuel production that must be interrogated and optimized to maximize fuel production. Here, we report the development of an IL-tolerant cellulase cocktail by combining thermophilic bacterial glycoside hydrolases produced by a mixed consortia with recombinant glycoside hydrolases. This enzymatic cocktail saccharifies IL-pretreated biomass at higher temperatures and in the presence of much higher IL concentrations than commercial fungal cocktails. Sugars obtained from saccharification of IL-pretreated switchgrass using this cocktail can be converted into biodiesel (fatty acid ethyl-esters or FAEEs) by a metabolically engineered strain of E. coli. During these studies, we found that this biodiesel-producing E. coli strain was sensitive to ILs and inhibitors released by saccharification. This cocktail will enable the development of novel biomass to biofuel bioprocessing configurations that may overcome some of the barriers to production of inexpensive cellulosic biofuels.

  14. CombiCap: A novel drug formulation for the basel phenotyping cocktail.

    Science.gov (United States)

    Camblin, Marine; Berger, Benjamin; Haschke, Manuel; Krähenbühl, Stephan; Huwyler, Jörg; Puchkov, Maxim

    2016-10-15

    Phenotyping of cytochrome P450 isoenzymes is used for metabolic profiling. Phenotyping cocktails are usually administered as individual marketed products, which are not designed for diagnostic applications. Therefore, a formulation strategy was developed, which can be applied to any phenotyping cocktail. The formulation was validated in vitro and in vivo in human volunteers using caffeine, efavirenz, flurbiprofen, metoprolol, midazolam, and omeprazole (Basel Cocktail). Spray dried di-calcium phosphate particles (Fujicalin) were used as an inert drug carrier for probe drugs. All drugs were successfully loaded into Fujicalin by a solvent evaporation method. Mini-tablets were produced and demonstrated good physical characteristics, expected drug content and immediate release profiles for all drug formulations. Mini-tablets were introduced into a capsule (CombiCap) and used for a pilot study in human volunteers. Plasma samples were collected and analyzed by liquid chromatography and mass spectrometry. Plasma concentration ratios between the parent drugs and the respective metabolites were equivalent for the novel CombiCap formulation and individually dosed Basel Cocktail drugs. We conclude that the CombiCap formulation platform can be easily adopted for different types of phenotyping cocktails due to its scalable and modular design, which allows a simple and convenient combination of variable doses of different probe drugs. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. STUDIES ON THE PURIFICATION OF BACTERIOPHAGE.

    Science.gov (United States)

    Kalmanson, G; Bronfenbrenner, J

    1939-11-20

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

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

    Science.gov (United States)

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

    2016-03-01

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

  17. Enhanced radioimmunotherapeutic efficacy of a monoclonal antibody cocktail against SMMC—7721 human hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    SONGYIQIANG; GENFENGWANG; 等

    1998-01-01

    The improved tumoricidal effect of the radioantibody mixture (“cocktail”)has been reported recently for the treatment of colon tumor.In the present study,we demonstrated the enhanced radioimmunotherapeutic efficacy of a monoclonal antibody (MAb) cocktail against human hepatocellular carcinoma.Therapeutic efficacy was determined by measuring the change in tumor size over a period,determining the percentage of growth inhibition of each treatment at various times after radioantibody therapy.Radioimmunotherapy of SMMC-7721 human hepatoma xenografts in athymic unde mice with combination of 131Ilabeled Hepama-1 and 131 I-labeled 9403 mouse MAbs was more effective than using either Hepeam-1 or 9403 MAb alone The MAb cocktail could target a greater number of hepatoma cells and increase the magnitude of hepatoma cell uptake of radioantibodies.The in vitro results explain the enhanced effect of the MAb cocktail in in vivo model system.

  18. [(≢SiO)TaVCl2Me2]: A well-defined silica-supported tantalum(V) surface complex as catalyst precursor for the selective cocatalyst-free trimerization of ethylene

    KAUST Repository

    Chen, Yin

    2012-10-22

    On the surface of it: In the absence of co-catalyst, a well-defined silica-supported surface organometallic complex [(≢SiO)Ta VCl2Me2] selectively catalyzes the oligomerization of ethylene. The use of surface organometallic species allows three different pathways to be determined for the reduction of TaV to TaIII species under pressure of ethylene. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Striking difference between alkane and olefin metathesis using the well-defined precursor [≡Si-O-WMe5]: Indirect evidence in favour of a bifunctional catalyst W alkylidene-hydride

    KAUST Repository

    Riache, Nassima

    2015-01-01

    Metathesis of linear alkanes catalyzed by the well-defined precursor (≡Si-O-WMe5) affords a wide distribution of linear alkanes from methane up to triacontane. Olefin metathesis using the same catalyst and under the same reaction conditions gives a very striking different distribution of linear α-olefins and internal olefins. This shows that olefin and alkane metathesis processes occur via very different pathways.

  20. Optimal drug cocktail design: methods for targeting molecular ensembles and insights from theoretical model systems.

    Science.gov (United States)

    Radhakrishnan, Mala L; Tidor, Bruce

    2008-05-01

    Drug resistance is a significant obstacle in the effective treatment of diseases with rapidly mutating targets, such as AIDS, malaria, and certain forms of cancer. Such targets are remarkably efficient at exploring the space of functional mutants and at evolving to evade drug binding while still maintaining their biological role. To overcome this challenge, drug regimens must be active against potential target variants. Such a goal may be accomplished by one drug molecule that recognizes multiple variants or by a drug "cocktail"--a small collection of drug molecules that collectively binds all desired variants. Ideally, one wants the smallest cocktail possible due to the potential for increased toxicity with each additional drug. Therefore, the task of designing a regimen for multiple target variants can be framed as an optimization problem--find the smallest collection of molecules that together "covers" the relevant target variants. In this work, we formulate and apply this optimization framework to theoretical model target ensembles. These results are analyzed to develop an understanding of how the physical properties of a target ensemble relate to the properties of the optimal cocktail. We focus on electrostatic variation within target ensembles, as it is one important mechanism by which drug resistance is achieved. Using integer programming, we systematically designed optimal cocktails to cover model target ensembles. We found that certain drug molecules covered much larger regions of target space than others, a phenomenon explained by theory grounded in continuum electrostatics. Molecules within optimal cocktails were often dissimilar, such that each drug was responsible for binding variants with a certain electrostatic property in common. On average, the number of molecules in the optimal cocktails correlated with the number of variants, the differences in the variants' electrostatic properties at the binding interface, and the level of binding affinity

  1. Towards an adequate regulatory framework for bacteriophage therapy

    OpenAIRE

    Verbeken, Gilbert

    2015-01-01

    Summary The worldwide emergence of antibiotic resistant bacteria and constraints to investment in potential solutions may eventually lead to a return to the pre-antibiotic era. As industries’ antibiotic pipeline is virtually dry and infectious diseases are steadily on the increase, the use of bacteriophages (bacteriophages are bacterio-specific viruses) to kill bacteria can be considered as a valuable option. Bacteriophages (meaning “bacteria-eaters”) are the bacteria’s natural enemie...

  2. Reduced responses of submucous neurons from irritable bowel syndrome patients to a cocktail containing histamine, serotonin, TNFα and tryptase (IBS-cocktail

    Directory of Open Access Journals (Sweden)

    Daniela eOstertag

    2015-12-01

    Full Text Available Background & Aims:Malfunctions of enteric neurons are believed to play an important role in the pathophysiology of irritable bowel syndrome (IBS. Our aim was to investigate whether neuronal activity in biopsies from IBS patients is altered in comparison to healthy controls (HC.Methods:Activity of human submucous neurons in response to electrical nerve stimulation and local application of nicotine or a mixture of histamine, serotonin, tryptase and TNF-α (IBS-cocktail was recorded in biopsies from 17 HC and 35 IBS patients with the calcium-sensitive-dye Fluo-4 AM. The concentrations of the mediators resembeled those found in biopsy supernatants or blood. Neuronal activity in guinea-pig submucous neurons was studied with the voltage-sensitive-dye di-8-ANEPPS. Results:Activity in submucous ganglia in response to nicotine or electrical nerve stimulation was not different between HC and IBS patients (P=0.097 or P=0.448. However, the neuronal response after application of the IBS-cocktail was significantly decreased (P=0.039 independent of whether diarrhea (n=12, constipation (n=5 or bloating (n=5 was the predominant symptom. In agreement with this we found that responses of submucous ganglia conditioned by overnight incubation with IBS mucosal biopsy supernatant to spritz application of this supernatant was significantly reduced (P=0.019 when compared to incubation with HC supernatant.Conclusion:We demonstrated for the first time reduced neuronal responses in mucosal IBS biopsies to an IBS mediator cocktail. While excitability to classical stimuli of enteric neurons was comparable to HC, the activation by the IBS-cocktail was decreased. This was very likely due to desensitization to mediators constantly released by mucosal and immune cells in the gut wall of IBS patients.

  3. Evolution and the complexity of bacteriophages

    Directory of Open Access Journals (Sweden)

    Serwer Philip

    2007-03-01

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

  4. Bacteriophage therapy: a potential solution for the antibiotic resistance crisis.

    Science.gov (United States)

    Golkar, Zhabiz; Bagasra, Omar; Pace, Donald Gene

    2014-02-13

    The emergence of multiple drug-resistant bacteria has prompted interest in alternatives to conventional antimicrobials. One of the possible replacement options for antibiotics is the use of bacteriophages as antimicrobial agents. Phage therapy is an important alternative to antibiotics in the current era of drug-resistant pathogens. Bacteriophages have played an important role in the expansion of molecular biology and have been used as antibacterial agents since 1966. In this review, we describe a brief history of bacteriophages and clinical studies on their use in bacterial disease prophylaxis and therapy. We discuss the advantages and disadvantages of bacteriophages as therapeutic agents in this regard.

  5. A first step toward liposome-mediated intracellular bacteriophage therapy.

    Science.gov (United States)

    Nieth, Anita; Verseux, Cyprien; Barnert, Sabine; Süss, Regine; Römer, Winfried

    2015-01-01

    The emergence of antibiotic-resistant bacteria presents a severe challenge to medicine and public health. While bacteriophage therapy is a promising alternative to traditional antibiotics, the general inability of bacteriophages to penetrate eukaryotic cells limits their use against resistant bacteria, causing intracellular diseases like tuberculosis. Bacterial vectors show some promise in carrying therapeutic bacteriophages into cells, but also bring a number of risks like an overload of bacterial antigens or the acquisition of virulence genes from the pathogen. As a first step in the development of a non-bacterial vector for bacteriophage delivery into pathogen-infected cells, we attempted to encapsulate bacteriophages into liposomes. Here we report effective encapsulation of the model bacteriophage λeyfp and the mycobacteriophage TM4 into giant liposomes. Furthermore, we show that liposome-associated bacteriophages are taken up into eukaryotic cells more efficiently than free bacteriophages. These are important milestones in the development of an intracellular bacteriophage therapy that might be useful in the fight against multi-drug-resistant intracellular pathogens like Mycobacterium tuberculosis.

  6. Application of bacteriophages in sensor development.

    Science.gov (United States)

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

    2016-03-01

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

  7. Detection of bacteria with bioluminescent reporter bacteriophage.

    Science.gov (United States)

    Klumpp, Jochen; Loessner, Martin J

    2014-01-01

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

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

    Science.gov (United States)

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

    2015-09-01

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

  9. Bacteriophages as recognition and identification agents

    Energy Technology Data Exchange (ETDEWEB)

    Teodorescu, M.C.; Gaspar, A.

    1987-04-23

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

  10. Going viral: designing bioactive surfaces with bacteriophage.

    Science.gov (United States)

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

    2014-12-01

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

  11. DNA Packaging in Bacteriophage: Is Twist Important?

    OpenAIRE

    Spakowitz, Andrew James; Wang, Zhen-Gang

    2005-01-01

    We study the packaging of DNA into a bacteriophage capsid using computer simulation, specifically focusing on the potential impact of twist on the final packaged conformation. We perform two dynamic simulations of packaging a polymer chain into a spherical confinement: one where the chain end is rotated as it is fed, and one where the chain is fed without end rotation. The final packaged conformation exhibits distinct differences in these two cases: the packaged conformation from feeding with...

  12. Genomic impact of CRISPR immunization against bacteriophages.

    Science.gov (United States)

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

    2013-12-01

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

  13. Genetically modified bacteriophages in applied microbiology.

    Science.gov (United States)

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

    2016-09-01

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

  14. 27 CFR 31.233 - Mixing cocktails in advance of sale.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Mixing cocktails in advance of sale. 31.233 Section 31.233 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND... liquors in advance of sale, except for the purpose of filling, for immediate consumption on the...

  15. Yeast mediates lactic acidosis suppression after antibiotic cocktail treatment in short small bowel?

    NARCIS (Netherlands)

    Bongaerts, G.P.A.; Severijnen, R.S.V.M.; Skladal, D.; Bakkeren, J.A.J.; Sperl, W.

    2005-01-01

    During acidotic periods in a girl with a short small bowel, very high D-lactic acid concentrations were measured in blood and urine; the patient's characteristic faecal flora contained mainly lactobacilli, and during antibiotic cocktail treatment also many yeasts. In this case report we sought to un

  16. Ataxin-10 is part of a cachexokine cocktail triggering cardiac metabolic dysfunction in cancer cachexia

    Directory of Open Access Journals (Sweden)

    Michaela Schäfer

    2016-02-01

    Conclusions: As Ataxin-10 serum levels were also found to be elevated in human cachectic cancer patients, the identification of Ataxin-10 as part of a cachexokine cocktail now provides a rational approach towards personalized predictive, diagnostic and therapeutic measures in cancer cachexia.

  17. Determination of polychlorinated biphenyls (PCBs) in insulating oil by cocktail PCB ELISA

    Energy Technology Data Exchange (ETDEWEB)

    Goda, Y.; Hirobe, M.; Fujimoto, S. [Japan EnviroChemicals Ltd., Tokyo (Japan); Tomita, J.; Nishikiori, M.; Nakajima, T. [Tokyo Electric Power Environmental Engineering Co. Inc., Tokyo (Japan); Rubio, F. [Abraxis LLC, Warminster, PA (United States); Takigami, H. [National Inst. for Environmental Studies, Tsukuba (Japan); Sakai, S. [Kyoto Univ., Kyoto (Japan). Environment Preservation Centre; Ike, M.; Fujita, M. [Osaka Univ., Osaka (Japan). Graduate School of Engineering

    2005-07-01

    This paper described a novel cocktail polychlorinated biphenyl (PCB) enzyme-linked immunosorbent assay (ELISA) designed as a simple pretreatment method for the determination of PCBs in insulating oils. Oil samples were treated with hexane and dimethyl sufloxide (DMSO) and mixed. Hexane layers were then removed, and freshly prepared hexane was added. The DMSO layer was then diluted with an aqueous solution and extracted with hexane. After being dehydrated, the hexane layer was sulfonated with a sulfuric reagent and washed. Standard or pretreated PCBs were then dissolved and diluted in 100 per cent DMSO and added to distilled water prior to the ELISA assay. A horseradish peroxidase conjugate and an anti-PCB antibody coupled with magnetic particles were added for the assay. A magnetic rack was used to separate the reaction mixture. A colouring reagent was then added. A total of 26 insulating oils contaminated with PCBs were determined using the new cocktail method and compared with data obtained from traditional gas chromatograph electron capture detector (GC-ECD) data. Results showed that the values of both the cocktail and general PCB ELISA were well correlated with the CG-ECD data. It was concluded that combining cocktail PCB ELISA with the developed pretreatment method provided accurate results. 3 refs., 4 tabs., 2 figs.

  18. Preparation of multi-locus DNA probe cocktail by liquid-phase reassociation.

    Science.gov (United States)

    Tamaki, Y; Fukuda, M; Kishida, T; Wang, W

    1995-08-01

    We developed a simple, rapid method for the preparation of a DNA-fingerprinting probe cocktail, and tested its usefulness in paternity testing. Exploiting the property of tandemly repetitive DNA segments to be rapidly renatured after heat denaturation, we enriched restriction fragments of a child's genomic DNA for minisatellites by liquid phase reassociation followed by capture with immobilized streptavidin. We amplified and simultaneously labeled the reassociation product by anchored PCR using a digoxigenin-labeling mixture. Using this probe cocktail, we were able to detect fingerprints of paternity case trios, and the results were corroborated by DNA fingerprinting with a commercially available probe as well as by conventional phenotyping. Our method enables one to prepare a fresh cocktail of probes from the DNA sample under study during the overnight electrophoresis and Southern transfer steps in DNA fingerprinting, and eliminates the need of having an expensive probe of limited shelf life. If one has a practical outlook on DNA fingerprinting and regard it as a preliminary test, one does not have to use a cloned DNA probe. The present study demonstrates that a multi-locus probe cocktail serves such a practical purpose.

  19. [Dendritic cells (DC) induced from acute myeloid leukemia (AML) cells with cytokine cocktails].

    Science.gov (United States)

    Yan, Kuang-hua; You, Sheng-guo; Bian, Shou-geng; Ma, Guan-jie; Ge, Wei; Ma, Shuang; Liu, Shi-he; Zhao, Chun-hua

    2003-07-01

    To explore the feasibility of DC being in vitro induced from AML cells with cytokine cocktails and their biological properties. AML cells were cultured in either presence or absence of cytokine cocktails. DC were studied for morphology, and cytochemical and immunofluorescent staining. Functions of DC were examined by MLC, FITC-conjugated dextran uptake test, and LDH release assay. RT-PCR and FISH were used to analyze the specific fusion genes of culture-derived DC. Classical DC morphological changes occurred in all 15 cultured AML cells. DC-associated surface molecules such as CD(1a), CD(80), CD(86), CD(106), CD(83) and HLA-DR were upregulated (P AML cells uncultured or cultured in the absence of cytokines (P CTL assay was performed in 5 of the 15 samples. At effector/target ratio of 20:1, auto-T lymphocytes primed with the culture-derived DC exhibited no more killing activity to auto-AML cells than those stimulated by IL-2 or uncultured AML cells. Culture-derived DC presenced the native AML-specific aberrant karyotype and related fusion gene. Cytokine cocktails could in vitro induce AML cells into DC with classical morphology, immunophenotype and function. DC maturity induced by different cytokine cocktails could be variable. Culture-derived DC were originated from the native AML cells. AML cells could make the auto-T lymphocyte anergy.

  20. Development of minimal enzyme cocktails for hydrolysis of sulfite-pulped lignocellulosic biomass.

    Science.gov (United States)

    Chylenski, Piotr; Forsberg, Zarah; Ståhlberg, Jerry; Várnai, Anikó; Lersch, Martin; Bengtsson, Oskar; Sæbø, Solve; Horn, Svein Jarle; Eijsink, Vincent G H

    2017-03-20

    Despite recent progress, saccharification of lignocellulosic biomass is still a major cost driver in biorefining. In this study, we present the development of minimal enzyme cocktails for hydrolysis of Norway spruce and sugarcane bagasse, which were pretreated using the so-called BALI™ process, which is based on sulfite pulping technology. Minimal enzyme cocktails were composed using several glycoside hydrolases purified from the industrially relevant filamentous fungus Trichoderma reesei and a purified commercial β-glucosidase from Aspergillus niger. The contribution of in-house expressed lytic polysaccharide monooxygenases (LPMOs) was also tested, since oxidative cleavage of cellulose by such LPMOs is known to be beneficial for conversion efficiency. We show that the optimized cocktails permit efficient saccharification at reasonable enzyme loadings and that the effect of the LPMOs is substrate-dependent. Using a cocktail comprising only four enzymes, glucan conversion for Norway spruce reached >80% at enzyme loadings of 8mg/g glucan, whereas almost 100% conversion was achieved at 16mg/g. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Experimental Study of Generalized Subspace Filters for the Cocktail Party Situation

    DEFF Research Database (Denmark)

    Christensen, Knud Bank; Christensen, Mads Græsbøll; Boldt, Jesper B.

    2016-01-01

    This paper investigates the potential performance of generalized subspace filters for speech enhancement in cocktail party situations with very poor signal/noise ratio, e.g. down to -15 dB. Performance metrics output signal/noise ratio, signal/ distortion ratio, speech quality rating and speech...

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

    Science.gov (United States)

    Bao, H; Zhang, H; Wang, R

    2011-10-01

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

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

    Science.gov (United States)

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

    2014-04-01

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

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

    Science.gov (United States)

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

    2012-12-01

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

  5. Química organometálica de superfície aplicada à preparação de catalisadores heterogêneos bem definidos Surface organometallic chemistry applied to the preparation of well defined heterogeneous catalysts

    Directory of Open Access Journals (Sweden)

    Silvana I. Wolke

    2002-11-01

    Full Text Available The study of the reactions of organometallic complexes with the surfaces of inorganic oxides, zeolites and metals constitutes the basis of Surface Organometallic Chemistry (SOMC. The basic rules of organometallic chemistry are often valid when applied to surfaces and well-defined surface organometallic complexes can be obtained. These complexes can be used as heterogeneous catalysts or, by controlled reactions, can be transformed in other species useful for a given catalytic reaction. In some cases, these catalysts exhibit higher activity and/or selectivity than their analogous molecular complexes.

  6. WMe6 tamed by silica: Si-O-WMe5 as an efficient, well-defined species for alkane metathesis, leading to the observation of a supported W-methyl/methylidyne species

    KAUST Repository

    Samantaray, Manoja

    2014-01-22

    The synthesis and full characterization of a well-defined silica-supported ≡Si-O-W(Me)5 species is reported. Under an inert atmosphere, it is a stable material at moderate temperature, whereas the homoleptic parent complex decomposes above -20 °C, demonstrating the stabilizing effect of immobilization of the molecular complex. Above 70 °C the grafted complex converts into the two methylidyne surface complexes [(≡SiO-)W(≡CH) Me2] and [(≡SiO-)2W(≡CH)Me]. All of these silica-supported complexes are active precursors for propane metathesis reactions. © 2013 American Chemical Society.

  7. Polyclonal antibody cocktails generated using DNA vaccine technology protect in murine models of orthopoxvirus disease

    Directory of Open Access Journals (Sweden)

    Ballantyne John

    2011-09-01

    Full Text Available Abstract Background Previously we demonstrated that DNA vaccination of nonhuman primates (NHP with a small subset of vaccinia virus (VACV immunogens (L1, A27, A33, B5 protects against lethal monkeypox virus challenge. The L1 and A27 components of this vaccine target the mature virion (MV whereas A33 and B5 target the enveloped virion (EV. Results Here, we demonstrated that the antibodies produced in vaccinated NHPs were sufficient to confer protection in a murine model of lethal Orthopoxvirus infection. We further explored the concept of using DNA vaccine technology to produce immunogen-specific polyclonal antibodies that could then be combined into cocktails as potential immunoprophylactic/therapeutics. Specifically, we used DNA vaccines delivered by muscle electroporation to produce polyclonal antibodies against the L1, A27, A33, and B5 in New Zealand white rabbits. The polyclonal antibodies neutralized both MV and EV in cell culture. The ability of antibody cocktails consisting of anti-MV, anti-EV, or a combination of anti-MV/EV to protect BALB/c mice was evaluated as was the efficacy of the anti-MV/EV mixture in a mouse model of progressive vaccinia. In addition to evaluating weight loss and lethality, bioimaging technology was used to characterize the spread of the VACV infections in mice. We found that the anti-EV cocktail, but not the anti-MV cocktail, limited virus spread and lethality. Conclusions A combination of anti-MV/EV antibodies was significantly more protective than anti-EV antibodies alone. These data suggest that DNA vaccine technology could be used to produce a polyclonal antibody cocktail as a possible product to replace vaccinia immune globulin.

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

    Directory of Open Access Journals (Sweden)

    Karam Jim D

    2005-03-01

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

  9. Genomic diversity of bacteriophages infecting the fish pathogen Flavobacterium psychrophilum.

    Science.gov (United States)

    Castillo, Daniel; Middelboe, Mathias

    2016-12-01

    Bacteriophages infecting the fish pathogen Flavobacterium psychrophilum can potentially be used to prevent and control outbreaks of this bacterium in salmonid aquaculture. However, the application of bacteriophages in disease control requires detailed knowledge on their genetic composition. To explore the diversity of F. pyschrophilum bacteriophages, we have analyzed the complete genome sequences of 17 phages isolated from two distant geographic areas (Denmark and Chile), including the previously characterized temperate bacteriophage 6H. Phage genome size ranged from 39 302 to 89 010 bp with a G+C content of 27%-32%. None of the bacteriophages isolated in Denmark contained genes associated with lysogeny, whereas the Chilean isolates were all putative temperate phages and similar to bacteriophage 6H. Comparative genome analysis showed that phages grouped in three different genetic clusters based on genetic composition and gene content, indicating a limited genetic diversity of F. psychrophilum-specific bacteriophages. However, amino acid sequence dissimilarity (25%) was found in putative structural proteins, which could be related to the host specificity determinants. This study represents the first analysis of genomic diversity and composition among bacteriophages infecting the fish pathogen F. psychrophilum and discusses the implications for the application of phages in disease control. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Experience of the Eliava Institute in bacteriophage therapy

    Institute of Scientific and Technical Information of China (English)

    Mzia; Kutateladze

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-04-01

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

  12. POSSIBILITES OF BACTERIOPHAGES APPLICATION IN SURGERY AND TRANSPLANTATION

    Directory of Open Access Journals (Sweden)

    N.I. Gabrielyan

    2012-01-01

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

  13. Characterization of Novel Bacteriophages for Biocontrol of Bacterial Blight in Leek Caused by Pseudomonas syringae pv. porri.

    Science.gov (United States)

    Rombouts, Sofie; Volckaert, Anneleen; Venneman, Sofie; Declercq, Bart; Vandenheuvel, Dieter; Allonsius, Camille N; Van Malderghem, Cinzia; Jang, Ho B; Briers, Yves; Noben, Jean P; Klumpp, Jochen; Van Vaerenbergh, Johan; Maes, Martine; Lavigne, Rob

    2016-01-01

    Pseudomonas syringae pv. porri, the causative agent of bacterial blight in leek (Allium porrum), is increasingly frequent causing problems in leek cultivation. Because of the current lack of control measures, novel bacteriophages were isolated to control this pathogen using phage therapy. Five novel phages were isolated from infected fields in Flanders (vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, vB_PsyM_KIL4, and vB_PsyM_KIL5), and were complemented with one selected host range mutant phage (vB_PsyM_KIL3b). Genome analysis of the phages revealed genome sizes between 90 and 94 kb and an average GC-content of 44.8%. Phylogenomic networking classified them into a novel clade, named the "KIL-like viruses," related to the Felixounalikevirus genus, together with phage phiPsa374 from P. syringae pv. actinidiae. In vitro characterization demonstrated the stability and lytic potential of these phages. Host range analysis confirmed heterogeneity within P. syringae pv. porri, leading to the development of a phage cocktail with a range that covers the entire set of 41 strains tested. Specific bio-assays demonstrated the in planta efficacy of phages vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, and vB_PsyM_KIL3b. In addition, two parallel field trial experiments on three locations using a phage cocktail of the six phages showed variable results. In one trial, symptom development was attenuated. These data suggest some potential for phage therapy in controlling bacterial blight of leek, pending optimization of formulation and application methods.

  14. Characterization of novel bacteriophages for biocontrol of bacterial blight in leek caused by Pseudomonas syringae pv. porri

    Directory of Open Access Journals (Sweden)

    Sofie eRombouts

    2016-03-01

    Full Text Available Pseudomonas syringae pv. porri, the causative agent of bacterial blight in leek (Allium porrum, is increasingly frequent causing problems in leek cultivation. Because of the current lack of control measures, novel bacteriophages were isolated to control this pathogen using phage therapy. Five novel phages were isolated from infected fields in Flanders (vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, vB_PsyM_KIL4 and vB_PsyM_KIL5, and were complemented with one selected host range mutant phage (vB_PsyM_KIL3b. Genome analysis of the phages revealed genome sizes between 90 and 94 kb and an average GC-content of 44.8%. Phylogenomic networking classified them into a novel clade, named the ‘KIL-like viruses’, related to the Felixounalikevirus genus, together with phage phiPsa374 from Pseudomonas syringae pv. actinidiae. In vitro characterization demonstrated the stability and lytic potential of these phages. Host range analysis confirmed heterogeneity within P. syringae pv. porri, leading to the development of a phage cocktail with a range that covers the entire set of 41 strains tested. Specific bio-assays demonstrated the in planta efficacy of phages vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3 and vB_PsyM_KIL3b. In addition, two parallel field trial experiments on three locations using a phage cocktail of the six phages showed variable results. In one trial, symptom development was attenuated. These data suggest some potential for phage therapy in controlling bacterial blight of leek, pending optimization of formulation and application methods.

  15. The Efficacy of Isolated Bacteriophages from Pig Farms against ESBL/AmpC-Producing Escherichia coli from Pig and Turkey Farms

    Science.gov (United States)

    Skaradzińska, Aneta; Śliwka, Paulina; Kuźmińska-Bajor, Marta; Skaradziński, Grzegorz; Rząsa, Anna; Friese, Anika; Roschanski, Nicole; Murugaiyan, Jayaseelan; Roesler, Uwe H.

    2017-01-01

    Extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases are plasmid (but also chromosomally) encoded enzymes found in Enterobacteriaceae, determining resistance to a variety of important antibiotics including penicillins, cephalosporins, and monobactams. In recent decades, the prevalence of ESBL/AmpC-producing bacteria has increased rapidly across the world. Here, we evaluate the potential use of bacteriophages in terms of a reduction of antibiotic-resistant bacteria in healthy animals. The aim of our studies was to isolate bacteriophages capable of destroying ESBL/AmpC-producing Escherichia coli isolated from livestock habitats. The efficacy of isolated phages against ESBL/AmpC E. coli strains varies, but creation of a phage cocktail with broad activity spectrum is possible. This may indicate that the role of phages may not be limited to phage therapy, but bacterial viruses may also be applied against spread of bacteria with antibiotic resistance genes in the environment. We also addressed the hypothesis, that phages, effective for therapeutic purposes may be isolated from distant places and even from different environments other than the actual location of the targeted bacteria. This may be beneficial for practical purposes, as the construction of effective phage preparations does not require access to disease outbreaks.

  16. M13 Bacteriophage Based Protein Sensors

    Science.gov (United States)

    Lee, Ju Hun

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

  17. Bacteriophages reduce experimental contamination of hard surfaces, tomato, spinach, broccoli, and ground beef by Escherichia coli O157:H7.

    Science.gov (United States)

    Abuladze, Tamar; Li, Manrong; Menetrez, Marc Y; Dean, Timothy; Senecal, Andre; Sulakvelidze, Alexander

    2008-10-01

    A bacteriophage cocktail (designated ECP-100) containing three Myoviridae phages lytic for Escherichia coli O157:H7 was examined for its ability to reduce experimental contamination of hard surfaces (glass coverslips and gypsum boards), tomato, spinach, broccoli, and ground beef by three virulent strains of the bacterium. The hard surfaces and foods contaminated by a mixture of three E. coli O157:H7 strains were treated with ECP-100 (test samples) or sterile phosphate-buffered saline buffer (control samples), and the efficacy of phage treatment was evaluated by comparing the number of viable E. coli organisms recovered from the test and control samples. Treatments (5 min) with the ECP-100 preparation containing three different concentrations of phages (10(10), 10(9), and 10(8) PFU/ml) resulted in statistically significant reductions (P = E. coli O157:H7 organisms recovered from the glass coverslips. Similar treatments resulted in reductions of 100%, 95%, and 85%, respectively, in the number of E. coli O157:H7 organisms recovered from the gypsum board surfaces; the reductions caused by the two most concentrated phage preparations were statistically significant. Treatment with the least concentrated preparation that elicited significantly less contamination of the hard surfaces (i.e., 10(9) PFU/ml) also significantly reduced the number of viable E. coli O157:H7 organisms on the four food samples. The observed reductions ranged from 94% (at 120 +/- 4 h posttreatment of tomato samples) to 100% (at 24 +/- 4 h posttreatment of spinach samples). The data suggest that naturally occurring bacteriophages may be useful for reducing contamination of various hard surfaces, fruits, vegetables, and ground beef by E. coli O157:H7.

  18. Ecological study of bacteriophages of Vibrio natriegens

    Energy Technology Data Exchange (ETDEWEB)

    Zachary, A.

    1978-03-01

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

  19. Bacteriophage biosensors for antibiotic-resistant bacteria.

    Science.gov (United States)

    Sorokulova, Irina; Olsen, Eric; Vodyanoy, Vitaly

    2014-03-01

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

  20. A mechanical model of bacteriophage DNA ejection

    Science.gov (United States)

    Arun, Rahul; Ghosal, Sandip

    2017-08-01

    Single molecule experiments on bacteriophages show an exponential scaling for the dependence of mobility on the length of DNA within the capsid. It has been suggested that this could be due to the ;capstan mechanism; - the exponential amplification of friction forces that result when a rope is wound around a cylinder as in a ship's capstan. Here we describe a desktop experiment that illustrates the effect. Though our model phage is a million times larger, it exhibits the same scaling observed in single molecule experiments.

  1. Genetic Exclusion in Bacteriophage T4.

    Science.gov (United States)

    1987-01-01

    ofI resource acquisition, but their genetic determinants are physicall .- linked and possibly co-regiulated or, the same sect ion of DNA. Thec o-eria...7473-7481. Garen, A. (1968). Sense and Nonsense in the Genetic Lode. Science 160:149-159. ( elIer, A. I . and A. rich (1980). A LGA ferarinatio...Mutants Deficient in rni Exclusion. Science 158:1588-1589. 11saio, C. L. and L. W. Black (1977). DNA Plackaging- and the Pathway of Bacteriophage T4

  2. Alkane metathesis with the tantalum methylidene [(≡SiO)Ta(=CH2)Me2]/[(≡SiO)2Ta(=CH2)Me] generated from well-defined surface organometallic complex [(≡SiO)TaVMe4

    KAUST Repository

    Chen, Yin

    2015-01-21

    By grafting TaMe5 on Aerosil700, a stable, well-defined, silica-supported tetramethyl tantalum(V) complex, [(≡SiO)TaMe4], is obtained on the silica surface. After thermal treatment at 150 °C, the complex is transformed into two surface tantalum methylidenes, [(≡SiO)2Ta(=CH2)Me] and [(≡SiO)Ta(=CH2)Me2], which are active in alkane metathesis and comparable to the previously reported [(≡SiO)2TaHx]. Here we present the first experimental study to isolate and identify a surface tantalum carbene as the intermediate in alkane metathesis. A systematic experimental study reveals a new reasonable pathway for this reaction.

  3. An In vivo Wound Model Utilizing Bacteriophage Therapy of Pseudomonas aeruginosa Biofilms.

    Science.gov (United States)

    Basu, Somprakas; Agarwal, Manav; Kumar Bhartiya, Satyanam; Nath, Gopal; Kumar Shukla, Vijay

    2015-08-01

    Bacteriophages have been used as effective therapy against bacterial biofilms on devices such as catheters, in the lungs such as in cystic fibrosis, and even in infected food. Unlike antibiotics, they are bacteria-specific and produce the desired effect without systemic complications; they can develop bacterial resistance, although in ways different from antibiotics. The present study aimed to assess the effect of bacteriophages against multidrug-resistant Pseudomonas aeruginosa in a mouse wound model. P. aeruginosa obtained from laboratory culture of burn wounds were characterized, harvested, and titrated, and biofilms were generated on sterile catheter sections (105 colony forming units/mL). Subcutaneous pockets were created on the backs of 24 male albino mice. Animals were randomized into 4 groups of 6 each. After evaluating a significant phage-bacteria interaction in vitro, 2 biofilm-laden catheter sections were implanted in subcutaneous pockets in mouse groups C and D. Sterile catheter sections only were implanted in group B. Group A had only a subcutaneous pocket without any catheter section. Phage cocktail solutions (10 \\'b5L of 107 phage forming units/mL) were injected daily in group D pockets only. Groups B and C received 10 \\'b5L of normal saline. After 10 days, the catheter sections were explanted from groups B, C, and D and tissue biopsy was taken from group A pockets and cultured for bacterial and phage colony counts. A significant drop in bacterial counts from 3.87 x 106 to 3.52 x 104 was observed in group D when compared with group C (3.87 x 106 to 3.85 x 105, P less than 0.05) A significant rise in the phage counts from 1 x 107 to 6.81 x 108 (P less than 0.05) also was observed in group D when compared with the baseline counts, indicating active phage proliferation and successful bacterial kill in group D. The present laboratory study could be indicative of a new treatment approach for multidrug-resistant bacterial infections, including wound

  4. Prospective randomized study of viscous lidocaine versus benzocaine in a GI cocktail for dyspepsia.

    Science.gov (United States)

    Vilke, Gary M; Jin, Albert; Davis, Daniel P; Chan, Theodore C

    2004-07-01

    We hypothesized that Benzocaine (Hurricaine) would work as quickly and effectively as viscous Lidocaine in this preparation. This was a prospective randomized, single-blinded comparison between Benzocaine and Lidocaine as the topical anesthetic in a gastrointestinal (GI) cocktail. Patients 18 years or older were approached for participation when a GI cocktail was ordered by the Emergency Physician. Patients were randomized to equivalent doses of either Benzocaine or viscous Lidocaine in addition to 30 cc of Maalox and 10 cc of Donnatal. Assessment using a visual analog pain scale occurred at time intervals of 0, 5, 15, and 30 min. Eighty-two patients were enrolled (44 to Benzocaine, 38 to viscous Lidocaine), with each group having a statistically significant improvement in pain (p Benzocaine and viscous Lidocaine groups in terms of the relief of symptoms at each of the assessment times. There were no adverse outcomes in either group.

  5. Anionic markers for the forensic identification of Chemical Ignition Molotov Cocktail composition.

    Science.gov (United States)

    Martín-Alberca, C; Ferrando, J L; García-Ruiz, C

    2013-03-01

    An improved version of the famous Molotov cocktail is the Chemical Ignition Molotov Cocktail (CIMC). This incendiary device contains chemical reagents that enable its self-ignition. The analysis of anions from CIMC residues by capillary electrophoresis (CE) allows the identification of the reagents used to produce the device, and provides forensic analysts with valuable information. Although, sulfate, chlorate, chloride, and perchlorate anions have been recently proposed in the literature as target anions to determine the CIMC composition, the identification of some of them could be controversial due to their presence in the environment. Therefore, the purpose of this study was to identify highly reliable anions capable of indicating the components used to prepare these self-initiated devices. The relationship among the detected anions in CIMC residues and the reagents employed in their elaboration is discussed. Some anions have been proposed as anionic markers of CIMC as incendiary devices. Additionally, the viability of different CIMC compositions was studied.

  6. Effect of a Thermoascus aurantiacus thermostable enzyme cocktail on wheat bread qualitiy.

    Science.gov (United States)

    Oliveira, D S; Telis-Romero, J; Da-Silva, R; Franco, C M L

    2014-01-15

    Thermophilic fungus Thermoascus aurantiacus (CBMAI 756) on solid-state fermentation using corncob as a nutrient source produces an enzyme pool with the potential to be used in bread making. In this paper, the use of this enzyme cocktail as a wheat bread improver was reported. Both products released by flour arabinoxylan degradation and bread quality were investigated. The main product released through enzyme activity after prolonged incubation was xylose indicating the presence of xylanase; however, a small amount of xylobiose and arabinose also confirmed the presence of xylosidase and α-l-arabinofuranosidase, respectively. Enzyme mixture "in vitro" mainly attacked water-unextractable arabinoxylan contributing to beneficial effect in bread making. The use of an optimal enzyme concentration (35U xylanase/100g of flour) increased specific volume (22%), reduced crumb firmness (25%), and reduced amylopectin retrogradation (17%) during bread storage. In conclusion, the enzyme cocktail produced by T. aurantiacus CBMAI 756 can improve wheat bread quality.

  7. Multi-exon Skipping Using Cocktail Antisense Oligonucleotides in the Canine X-linked Muscular Dystrophy.

    Science.gov (United States)

    Miskew Nichols, Bailey; Aoki, Yoshitsugu; Kuraoka, Mutsuki; Lee, Joshua J A; Takeda, Shin'ichi; Yokota, Toshifumi

    2016-05-24

    Duchenne muscular dystrophy (DMD) is one of the most common lethal genetic diseases worldwide, caused by mutations in the dystrophin (DMD) gene. Exon skipping employs short DNA/RNA-like molecules called antisense oligonucleotides (AONs) that restore the reading frame and produce shorter but functional proteins. However, exon skipping therapy faces two major hurdles: limited applicability (up to only 13% of patients can be treated with a single AON drug), and uncertain function of truncated proteins. These issues were addressed with a cocktail AON approach. While approximately 70% of DMD patients can be treated by single exon skipping (all exons combined), one could potentially treat more than 90% of DMD patients if multiple exon skipping using cocktail antisense drugs can be realized. The canine X-linked muscular dystrophy (CXMD) dog model, whose phenotype is more similar to human DMD patients, was used to test the systemic efficacy and safety of multi-exon skipping of exons 6 and 8. The CXMD dog model harbors a splice site mutation in intron 6, leading to a lack of exon 7 in dystrophin mRNA. To restore the reading frame in CXMD requires multi-exon skipping of exons 6 and 8; therefore, CXMD is a good middle-sized animal model for testing the efficacy and safety of multi-exon skipping. In the current study, a cocktail of antisense morpholinos targeting exon 6 and exon 8 was designed and it restored dystrophin expression in body-wide skeletal muscles. Methods for transfection/injection of cocktail oligos and evaluation of the efficacy and safety of multi-exon skipping in the CXMD dog model are presented.

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

    OpenAIRE

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

    2016-01-01

    In this study, we investigated the humoral immune response (through the release of IgG, IgA, and IgM antiphage antibodies) to a staphylococcal phage cocktail in patients undergoing experimental phage therapy at the Phage Therapy Unit, Medical Center of the Ludwik Hirszfeld Institute of Immunology and Experimental Therapy in Wrocław, Poland. We also evaluated whether occurring antiphage antibodies had neutralizing properties towards applied phages (K rate). Among 20 examined patients receiving...

  9. A Combination Cocktail Improves Spatial Attention in a Canine Model of Human Aging and Alzheimer's disease

    Science.gov (United States)

    Head, Elizabeth; Murphey, Heather L.; Dowling, Amy L.S.; McCarty, Katie L.; Bethel, Samuel R.; Nitz, Jonathan A.; Pleiss, Melanie; Vanrooyen, Jenna; Grossheim, Mike; Smiley, Jeffery R.; Murphy, M. Paul; Beckett, Tina L.; Pagani, Dieter; Bresch, Frederick; Hendrix, Curt

    2014-01-01

    Alzheimer's disease (AD) involves multiple pathological processes in the brain, including increased inflammation and oxidative damage, as well as the accumulation of beta-amyloid (Aβ) plaques. We hypothesized that a combinatorial therapeutic approach to target these multiple pathways may provide cognitive and neuropathological benefits for AD patients. To test this hypothesis, we used a canine model of human aging and AD. Aged dogs naturally develop learning and memory impairments, human-type Aβ deposits and oxidative damage in the brain. Thus, 9 aged beagles (98-115 months) were treated with a medical food cocktail containing (1) an extract of turmeric containing 95% curcuminoids; (2) an extract of green tea containing 50% epigallocatechingallate; (3) N-acetyl cysteine; (4) R-alpha lipoic acid; and (5) an extract of black pepper containing 95% piperine. Nine similarly aged dogs served as placebo-treated controls. After 3 months of treatment, 13 dogs completed a variable distance landmark task used as a measure of spatial attention. As compared to placebo-treated animals, dogs receiving the medical food cocktail had significantly lower error scores (t(11)=4.3, p=0.001) and were more accurate across all distances (F(1,9)=20.7, p=0.001), suggesting an overall improvement in spatial attention. Measures of visual discrimination learning, executive function and spatial memory, and levels of brain and CSF Aβ were unaffected by the cocktail. Our results indicate that this medical food cocktail may be beneficial for improving spatial attention and motivation deficits associated with impaired cognition in aging and AD. PMID:22886019

  10. Root exudate cocktails: the link between plant diversity and soil microorganisms?

    Science.gov (United States)

    Steinauer, Katja; Chatzinotas, Antonis; Eisenhauer, Nico

    2016-10-01

    Higher plant diversity is often associated with higher soil microbial biomass and diversity, which is assumed to be partly due to elevated root exudate diversity. However, there is little experimental evidence that diversity of root exudates shapes soil microbial communities. We tested whether higher root exudate diversity enhances soil microbial biomass and diversity in a plant diversity gradient, thereby negating significant plant diversity effects on soil microbial properties. We set up plant monocultures and two- and three-species mixtures in microcosms using functionally dissimilar plants and soil of a grassland biodiversity experiment in Germany. Artificial exudate cocktails were added by combining the most common sugars, organic acids, and amino acids found in root exudates. We applied four different exudate cocktails: two exudate diversity levels (low- and high-diversity) and two nutrient-enriched levels (carbon- and nitrogen-enriched), and a control with water only. Soil microorganisms were more carbon- than nitrogen-limited. Cultivation-independent fingerprinting analysis revealed significantly different soil microbial communities among exudate diversity treatments. Most notably and according to our hypothesis, adding diverse exudate cocktails negated the significant plant diversity effect on soil microbial properties. Our findings provide the first experimental evidence that root exudate diversity is a crucial link between plant diversity and soil microorganisms.

  11. The intravesicular cocktail and its role in the regulation of exocytosis.

    Science.gov (United States)

    Estévez-Herrera, Judith; González-Santana, Ayoze; Baz-Dávila, Rebeca; Machado, José D; Borges, Ricardo

    2016-06-01

    The accumulation of neurotransmitters within secretory vesicles (SVs) far exceeds the theoretical tonic concentrations in the cytosol, a phenomenon that has captivated the attention of scientists for decades. For instance, chromaffin granules can accumulate close to molar concentrations of catecholamines, along with many other products like ATP, calcium, peptides, chromogranins, ascorbate, and other nucleotides. In this short review, we will summarize the interactions that are currently believed to occur between the elements that make up the vesicular cocktail in the acidic environment of SVs, and how they permit the accumulation of such high concentrations of certain components. In addition, we will examine how the vesicular cocktail regulates the exocytosis of neurotransmitters. In this review, we have highlighted the mechanisms that permit the storage of neurotransmitters and hormones inside secretory vesicles. We also have proposed a novel model based in the intravesicular interactions of the main components of this inner cocktail - catecholamines, ATP, and chromogranins - to allow the accumulation of near molar concentrations of transmitters in secretory vesicles. This article is part of a mini review series on Chromaffin cells (ISCCB Meeting, 2015).

  12. Production of cocktail of polyclonal antibodies using bacterial expressed recombinant protein for multiple virus detection.

    Science.gov (United States)

    Kapoor, Reetika; Mandal, Bikash; Paul, Prabir Kumar; Chigurupati, Phaneendra; Jain, Rakesh Kumar

    2014-02-01

    Cocktail of polyclonal antibodies (PAb) were produced that will help in multiple virus detection and overcome the limitation of individual virus purification, protein expression and purification as well as immunization in multiple rabbits. A dual fusion construct was developed using conserved coat protein (CP) sequences of Cucumber mosaic virus (CMV) and Papaya ringspot virus (PRSV) in an expression vector, pET-28a(+). The fusion protein (∼40kDa) was expressed in Escherichia coli and purified. Likewise, a triple fusion construct was developed by fusing conserved CP sequences of CMV and PRSV with conserved nucleocapsid protein (N) sequence of Groundnut bud necrosis virus (GBNV) and expressed as a fusion protein (∼50kDa) in pET-28a(+). PAb made separately to each of these three viruses recognized the double and triple fusion proteins in Western blot indicating retention of desired epitopes for binding with target antibodies. The fusion proteins (∼40kDa and ∼50kDa) were used to produce cocktail of PAb by immunizing rabbits, which simultaneously detected natural infection of CMV and PRSV or CMV, PRSV and GBNV in Cucurbitaceous, Solanaceous and other hosts in DAC-ELISA. This is the first report on production of a cocktail of PAb to recombinant fusion protein of two or three distinct viruses.

  13. The role of bacteriophages in periodontal health and disease.

    Science.gov (United States)

    Pinto, Graça; Silva, Maria Daniela; Peddey, Mark; Sillankorva, Sanna; Azeredo, Joana

    2016-10-01

    The human periodontium health is commonly compromised by chronic inflammatory conditions and has become a major public health concern. Dental plaque, the precursor of periodontal disease, is a complex biofilm consisting mainly of bacteria, but also archaea, protozoa, fungi and viruses. Viruses that specifically infect bacteria - bacteriophages - are most common in the oral cavity. Despite this, their role in the progression of periodontal disease remains poorly explored. This review aims to summarize how bacteriophages interact with the oral microbiota, their ability to increase bacterial virulence and mediate the transfer of resistance genes and suggests how bacteriophages can be used as an alternative to the current periodontal disease therapies.

  14. Complete Genome Sequence of Phytopathogenic Pectobacterium atrosepticum Bacteriophage Peat1.

    Science.gov (United States)

    Kalischuk, Melanie; Hachey, John; Kawchuk, Lawrence

    2015-08-13

    Pectobacterium atrosepticum is a common phytopathogen causing significant economic losses worldwide. To develop a biocontrol strategy for this blackleg pathogen of solanaceous plants, P. atrosepticum bacteriophage Peat1 was isolated and its genome completely sequenced. Interestingly, morphological and sequence analyses of the 45,633-bp genome revealed that phage Peat1 is a member of the family Podoviridae and most closely resembles the Klebsiella pneumoniae bacteriophage KP34. This is the first published complete genome sequence of a phytopathogenic P. atrosepticum bacteriophage, and details provide important information for the development of biocontrol by advancing our understanding of phage-phytopathogen interactions.

  15. Respirable bacteriophages for the treatment of bacterial lung infections.

    Science.gov (United States)

    Hoe, Susan; Semler, Diana D; Goudie, Amanda D; Lynch, Karlene H; Matinkhoo, Sadaf; Finlay, Warren H; Dennis, Jonathan J; Vehring, Reinhard

    2013-12-01

    This review article discusses the development of respiratory therapeutics containing bacteriophages indicated for lung infections, specifically those that have become increasingly difficult to treat because of antibiotic resistance. Recent achievements and remaining problems are presented for each step necessary to develop a bacteriophage-containing dosage form for respiratory drug delivery, including selection of appropriate bacteriophages for therapy, processing and purification of phage preparations, formulation into a stable, solid dosage form, and delivery device selection. Safety and efficacy studies in animals and human subjects are also reviewed.

  16. Bacteriophage therapy in implant-related infections: an experimental study.

    Science.gov (United States)

    Yilmaz, Cengiz; Colak, Mehmet; Yilmaz, Banu Coskun; Ersoz, Gulden; Kutateladze, Mzia; Gozlugol, Mehmet

    2013-01-16

    Implant-related infections with bacteria resistant to multiple antibiotics represent one of the major problems in orthopaedic surgery. It was our hypothesis that local application of bacteriophages, which are bacteria-destroying viruses, would be effective against biofilm-forming bacteria. An implant-related infection model was created using methicillin-resistant Staphylococcus aureus (MRSA) in forty-eight rats and Pseudomonas aeruginosa in another forty-eight rats. Each group was divided into four subgroups; one subgroup received a bacterium-specific bacteriophage (Sb-1 in the MRSA group and PAT14 in the Pseudomonas aeruginosa group), one received antibiotic for fourteen days (20 mg/kg/day teicoplanin in the MRSA group, and 120 mg/kg/day imipenem + cilastatin and 25 mg/kg/day amikacin in the Pseudomonas group), one received antibiotic and bacteriophage, and one received no treatment. Animals receiving bacteriophage therapy were injected locally with 107 bacteriophages in a 0.1-mL suspension on three consecutive days. All animals were killed on the fifteenth day after initiation of treatment, and the tibia was excised. Results were assessed with use of microbiology, light microscopy, and electron microscopy. In the MRSA group, the antibiotic administration significantly decreased the number of colony-forming units per subject in quantitative cultures (control subgroup, 50,586; bacteriophage, 30,788; antibiotic, 17,165; antibiotic + bacteriophage, 5000; p = 0.004 for the comparison of the latter group with the control). Biofilm was absent only in the antibiotic + bacteriophage subgroup. In the Pseudomonas group, the number of colony-forming units per subject in quantitative cultures was significantly lower in each treatment subgroup compared with the control subgroup (control subgroup, 14,749; bacteriophage, 6484 [p = 0.016]; antibiotic, 2619 [p = 0.01]; antibiotic + bacteriophage, 1705 [p bacteriophage subgroup was also significantly lower than the values in the

  17. Bacteriophages and their role in food safety.

    Science.gov (United States)

    Sillankorva, Sanna M; Oliveira, Hugo; Azeredo, Joana

    2012-01-01

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

  18. Bacteriophages and Their Role in Food Safety

    Directory of Open Access Journals (Sweden)

    Sanna M. Sillankorva

    2012-01-01

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

  19. Genome landscapes and bacteriophage codon usage.

    Directory of Open Access Journals (Sweden)

    Julius B Lucks

    2008-02-01

    Full Text Available Across all kingdoms of biological life, protein-coding genes exhibit unequal usage of synonymous codons. Although alternative theories abound, translational selection has been accepted as an important mechanism that shapes the patterns of codon usage in prokaryotes and simple eukaryotes. Here we analyze patterns of codon usage across 74 diverse bacteriophages that infect E. coli, P. aeruginosa, and L. lactis as their primary host. We use the concept of a "genome landscape," which helps reveal non-trivial, long-range patterns in codon usage across a genome. We develop a series of randomization tests that allow us to interrogate the significance of one aspect of codon usage, such as GC content, while controlling for another aspect, such as adaptation to host-preferred codons. We find that 33 phage genomes exhibit highly non-random patterns in their GC3-content, use of host-preferred codons, or both. We show that the head and tail proteins of these phages exhibit significant bias towards host-preferred codons, relative to the non-structural phage proteins. Our results support the hypothesis of translational selection on viral genes for host-preferred codons, over a broad range of bacteriophages.

  20. Understanding Bacteriophage Specificity in Natural Microbial Communities

    Directory of Open Access Journals (Sweden)

    Britt Koskella

    2013-03-01

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

  1. Bacteriophage recombination systems and biotechnical applications.

    Science.gov (United States)

    Nafissi, Nafiseh; Slavcev, Roderick

    2014-04-01

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

  2. Broad-range lytic bacteriophages that kill Staphylococcus aureus local field strains.

    Science.gov (United States)

    Abatángelo, Virginia; Peressutti Bacci, Natalia; Boncompain, Carina A; Amadio, Ariel A; Carrasco, Soledad; Suárez, Cristian A; Morbidoni, Héctor R

    2017-01-01

    Staphylococcus aureus is a very successful opportunistic pathogen capable of causing a variety of diseases ranging from mild skin infections to life-threatening sepsis, meningitis and pneumonia. Its ability to display numerous virulence mechanisms matches its skill to display resistance to several antibiotics, including β-lactams, underscoring the fact that new anti-S. aureus drugs are urgently required. In this scenario, the utilization of lytic bacteriophages that kill bacteria in a genus -or even species- specific way, has become an attractive field of study. In this report, we describe the isolation, characterization and sequencing of phages capable of killing S. aureus including methicillin resistant (MRSA) and multi-drug resistant S. aureus local strains from environmental, animal and human origin. Genome sequencing and bio-informatics analysis showed the absence of genes encoding virulence factors, toxins or antibiotic resistance determinants. Of note, there was a high similarity between our set of phages to others described in the literature such as phage K. Considering that reported phages were obtained in different continents, it seems plausible that there is a commonality of genetic features that are needed for optimum, broad host range anti-staphylococcal activity of these related phages. Importantly, the high activity and broad host range of one of our phages underscores its promising value to control the presence of S. aureus in fomites, industry and hospital environments and eventually on animal and human skin. The development of a cocktail of the reported lytic phages active against S. aureus-currently under way- is thus, a sensible strategy against this pathogen.

  3. SynTec Final Technical Report: Synthetic biology for Tailored Enzyme cocktails

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Janine [Novozymes, Inc., Davis, CA (United States); Teter, Sarah [Novozymes, Inc., Davis, CA (United States)

    2016-06-30

    Using a novel enzyme screening method inspired by synthetic biology, Novozymes developed new technology under SynTec which allows for more rapidly tailoring of enzyme cocktails. The methodology can be applied to specific feedstocks, and or coupled to address a specific hydrolytic conversion process context. Using combinatorial high throughput screening of libraries of enzyme domains, we can quickly assess which combination of catalytic modules delivers the best performance for a specific condition. To demonstrate the effectiveness of the screening process, we measured performance of the output catalytic cocktail compared to CTec3/HTec3. SynTec benchmark cocktail - blend of Cellic® CTec3 and HTec3. The test substrate was - ammonia fiber expansion pretreated corn stover (AFEX™ PCS).CTec3/HTec3 was assayed at the optimal pH and temperature, and also in the absence of any pH adjustment. The new enzyme cocktail discovered under SynTec was assayed in the absence of any pH adjustment and at the optimal temperature. Conversion is delivered by SynTec enzyme at significant dose reduction relative to CTec3/HTec3 at the controlled pH optimum, and without titrant required to maintain pH, which delivers additional cost savings relative to current state of the art process. In this 2.5 year $4M project, the team delivered an experimental cocktail that significantly outperformed CTec3/HTec3 for a specific substrate, and for specific hydrolysis conditions. As a means of comparing performance improvement delivered per research dollar spent, we note that SynTec delivered a similar performance improvement to the previous award, in a shorter time and with fewer resources than for the previously successful DOE project DECREASE, a 3.5 year, $25M project, though this project focused on a different substrate and used different hydrolysis conditions. The newly implemented technology for rapid sourcing of new cellulases and hemicellulases from nature is an example of Novozymes

  4. Stabilization of T4 bacteriophage at acidic and basic pH by adsorption on paper.

    Science.gov (United States)

    Meyer, Abigail; Greene, Melissa; Kimmelshue, Chad; Cademartiri, Rebecca

    2017-09-05

    Bacteriophages find applications in agriculture, medicine, and food safety. Many of these applications can expose bacteriophages to stresses that inactivate them including acidic and basic pH. Bacteriophages can be stabilized against these stresses by materials including paper, a common material in packaging and consumer products. Combining paper and bacteriophages creates antibacterial materials, which can reduce the use of antibiotics. Here we show that adsorption on paper protects T4, T5, and T7 bacteriophage from acidic and basic pH. We added bacteriophages to filter paper functionalized with carboxylic acid (carboxyl methyl cellulose) or amine (chitosan) groups, and exposed them to pH from 5.6 to 14. We determined the number of infective bacteriophages after exposure directly on the paper. All papers extended the lifetime of infective bacteriophage by at least a factor of four with some papers stabilizing bacteriophages for up to one week. The degree of stabilization depended on five main factors (i) the family of the bacteriophage, (ii) the charge of the paper and bacteriophages, (iii) the location of the bacteriophages within the paper, (iv) the ability of the paper to prevent bacteriophage-bacteriophage aggregation, and (v) the sensitivity of the bacteriophage proteins to the tested pH. Even when adsorbed on paper the bacteriophages were able to remove E. coli in milk. Choosing the right paper modification or material will protect bacteriophages adsorbed on that material against detrimental pH and other environmental challenges increasing the range of applications of bacteriophages on materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Well-defined crystallites autoclaved from the nitrate/NH{sub 4}OH reaction system as the precursor for (Y,Eu){sub 2}O{sub 3} red phosphor: Crystallization mechanism, phase and morphology control, and luminescent property

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Qi [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004 (China); Advanced Materials Processing Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan); Li Jiguang, E-mail: LI.Jiguang@nims.go.jp [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004 (China); Advanced Materials Processing Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan); Ma, Renzhi; Sasaki, Takayoshi [World Premier International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan); Yang, Xiaojing [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Li Xiaodong; Sun Xudong [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004 (China); Sakka, Yoshio [Advanced Materials Processing Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan)

    2012-08-15

    Autoclaving the rare-earth nitrate/NH{sub 4}OH reaction system under the mild conditions of 120-200 Degree-Sign C and pH 6-13 have yielded four types of well-crystallized compounds with their distinctive crystal shapes, including Ln{sub 2}(OH){sub 5}NO{sub 3}{center_dot}nH{sub 2}O (Ln=Y and Eu) layered rare-earth hydroxide (hexagonal platelets), Ln{sub 4}O(OH){sub 9}NO{sub 3} oxy-hydroxyl nitrate (hexagonal prisms and microwires), Ln(OH){sub 2.94}(NO{sub 3}){sub 0.06}{center_dot}nH{sub 2}O hydroxyl nitrate (square nanoplates), and Ln(OH){sub 3} hydroxide (spindle-shaped microrods). The occurrence domains of the compounds are defined. Ammonium nitrate (NH{sub 4}NO{sub 3}) as a mineralizer effectively widens the formation domains of the NO{sub 3}{sup -} containing compounds while leads to larger crystals at the same time (up to 0.3 mm). Crystallization mechanisms of the compounds and the effects of NH{sub 4}NO{sub 3} were discussed. Optical properties (PLE/PL) of the four phases were characterized in detail and were interpreted from the different site symmetries of Eu{sup 3+}. The compounds convert to cubic-structured (Y{sub 0.95}Eu{sub 0.05}){sub 2}O{sub 3} by annealing at 600 Degree-Sign C while retaining their original crystal morphologies. The resultant phosphor oxides of diverse particle shapes exhibit differing optical properties, in terms of luminescent intensity, asymmetry factor of luminescence and fluorescence lifetime, and the underlying mechanism was discussed. - Graphical abstract: Well-defined crystallites of the various phases have been autoclaved from the nitrate/NH{sub 4}OH reaction system. Crystallization mechanisms of the compounds and the effects of NH{sub 4}NO{sub 3} were discussed. Highlights: Black-Right-Pointing-Pointer Well-defined crystallites of four phases have been hydrothermally synthesized. Black-Right-Pointing-Pointer The occurrence domains of the compounds are defined. Black-Right-Pointing-Pointer Crystallization mechanisms and the

  6. Antimicrobial bacteriophage-derived proteins and therapeutic applications

    Science.gov (United States)

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

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

    Science.gov (United States)

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

    2016-01-01

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

  8. 21 CFR 172.785 - Listeria-specific bacteriophage preparation.

    Science.gov (United States)

    2010-04-01

    ... FOOD FOR HUMAN CONSUMPTION Other Specific Usage Additives § 172.785 Listeria -specific bacteriophage... Nutrition's Library, 5100 Paint Branch Pkwy., College Park, MD 20740, or at the National Archives...

  9. Bacteriophages as potential new therapeutics to replace or supplement antibiotics.

    Science.gov (United States)

    Kutateladze, Mzia; Adamia, Revaz

    2010-12-01

    Over recent decades, a growing body of literature has validated the use of bacteriophages for therapy and prophylaxis in the war against drug-resistant bacteria. Today, much more is known about bacteriophages than in the 1930s when phage therapy first appeared and began to spread to many countries. With rapid dissemination of multi-drug-resistant bacterial pathogens, the interest in alternative remedies to antibiotics, including bacteriophage treatments, is gaining new ground. Based on recent experience and current results of bacteriophage applications against bacterial infections in countries where this alternative therapy is approved, many scientists and companies have come to believe that the use of phages for treating and preventing bacterial diseases will be successful.

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

    Directory of Open Access Journals (Sweden)

    Muhammad Abu Bakr Shabbir

    2016-08-01

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

  11. Bacteriophage therapy: an alternative to antibiotic therapy in aquaculture?

    National Research Council Canada - National Science Library

    Morrison, S; Rainnie, D.J

    2004-01-01

    This report documents one aspect of the atypical furunculosis research program, namely a literature reiew of bacteriophage treatment, either by itself or in combination with other approaches to disease intervention. Le...

  12. Modular Approach to Select Bacteriophages Targeting Pseudomonas aeruginosa for Their Application to Children Suffering With Cystic Fibrosis

    Science.gov (United States)

    Krylov, Victor; Shaburova, Olga; Pleteneva, Elena; Bourkaltseva, Maria; Krylov, Sergey; Kaplan, Alla; Chesnokova, Elena; Kulakov, Leonid; Magill, Damian; Polygach, Olga

    2016-01-01

    This review discusses the potential application of bacterial viruses (phage therapy) toward the eradication of antibiotic resistant Pseudomonas aeruginosa in children with cystic fibrosis (CF). In this regard, several potential relationships between bacteria and their bacteriophages are considered. The most important aspect that must be addressed with respect to phage therapy of bacterial infections in the lungs of CF patients is in ensuring the continuity of treatment in light of the continual occurrence of resistant bacteria. This depends on the ability to rapidly select phages exhibiting an enhanced spectrum of lytic activity among several well-studied phage groups of proven safety. We propose a modular based approach, utilizing both mono-species and hetero-species phage mixtures. With an approach involving the visual recognition of characteristics exhibited by phages of well-studied phage groups on lawns of the standard P. aeruginosa PAO1 strain, the simple and rapid enhancement of the lytic spectrum of cocktails is permitted, allowing the development of tailored preparations for patients capable of circumventing problems associated with phage resistant bacterial mutants. PMID:27790211

  13. Modular approach to select bacteriophages targeting Pseudomonas aeruginosa for their application to children suffering with cystic fibrosis

    Directory of Open Access Journals (Sweden)

    Victor Krylov

    2016-10-01

    Full Text Available This review discusses the potential application of bacterial viruses (phage therapy towards the eradication of antibiotic resistant Pseudomonas aeruginosa in children with cystic fibrosis (CF. In this regard, several potential relationships between bacteria and their bacteriophages are considered. The most important aspect that must be addressed with respect to phage therapy of bacterial infections in the lungs of CF patients is in ensuring the continuity of treatment in light of the continual occurrence of resistant bacteria. This depends on the ability to rapidly select phages exhibiting an enhanced spectrum of lytic activity among several well-studied phage groups of proven safety. We propose a modular based approach, utilizing both mono-species and hetero-species phage mixtures. With an approach involving the visual recognition of characteristics exhibited by phages of well-studied phage groups on lawns of the standard P. aeruginosa PAO1 strain, the simple and rapid enhancement of the lytic spectrum of cocktails is permitted, allowing the development of tailored preparations for patients capable of circumventing problems associated with phage resistant bacterial mutants.

  14. Bacteriophage-based nanoprobes for rapid bacteria separation

    Science.gov (United States)

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

    2015-10-01

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

  15. Sequence and comparative analysis of Leuconostoc dairy bacteriophages

    DEFF Research Database (Denmark)

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

    2014-01-01

    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......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...

  16. Methods for initial characterization of Campylobacter jejuni bacteriophages

    DEFF Research Database (Denmark)

    Sørensen, Martine Camilla Holst; Gencay, Yilmaz Emre; Brøndsted, Lone

    2017-01-01

    Here we describe an initial characterization of Campylobacter jejuni bacteriophages by host range analysis, genome size determination by pulsed-field gel electrophoresis, and receptor-type identification by screening mutants for phage sensitivity.......Here we describe an initial characterization of Campylobacter jejuni bacteriophages by host range analysis, genome size determination by pulsed-field gel electrophoresis, and receptor-type identification by screening mutants for phage sensitivity....

  17. Complete Genome Sequence of Phytopathogenic Pectobacterium atrosepticum Bacteriophage Peat1

    OpenAIRE

    Kalischuk, Melanie; Hachey, John; Kawchuk, Lawrence

    2015-01-01

    Pectobacterium atrosepticum is a common phytopathogen causing significant economic losses worldwide. To develop a biocontrol strategy for this blackleg pathogen of solanaceous plants, P. atrosepticum bacteriophage Peat1 was isolated and its genome completely sequenced. Interestingly, morphological and sequence analyses of the 45,633-bp genome revealed that phage Peat1 is a member of the family Podoviridae and most closely resembles the Klebsiella pneumoniae bacteriophage KP34. This is the fir...

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

    Institute of Scientific and Technical Information of China (English)

    Hongping; Wei

    2015-01-01

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

  19. Genome Sequences of Three Novel Bacillus cereus Bacteriophages

    OpenAIRE

    Julianne H Grose; 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.

  20. An infertile case of 47,XYY syndrome without autistic spectrum: Cost effective well-define of extra Y chromosome by GTG, C bandings, QF-PCR and FISH analyses

    Directory of Open Access Journals (Sweden)

    Özturk Özdemir

    2016-12-01

    Full Text Available The Autism Spectrum Disorders (ASD was frequently reported in autosomal and sex chromosome abnormalities and limited findings pointed out the Y chromosome. In the current case, it was aimed to identify the genetic cause for a man without autism profiles using combined cytogenetic and molecular genetic techniques. Automated karyotype analysis was made after combined methods with GTG, C bandings, QF-PCR and FISH techniquesfor the current case. Additional Y chromosome was identified after conventional GTG and C-banded karyotype analysis. The current case of 47,XYY syndrome was reported due to without autistic profiles such as language and social impairment. The proband’s karyotype was determined as 47,XYY. No other numerical and/or structural chromosomal abnormalities were detected in the karyotype analysis. Cytogenetic methods combined with cost-effective techniques such as C, GTG banding and FISH provide well-define of extra Y chromosome in the presented case of without autistic spectrum. Both Y chromosomes were in the same size and C-banded profiles in the current proband pointed out that both are originated from one chromosome by endoreduplication Y chromosome after zigot formation

  1. Well-Defined Surface Species [(≡Si - O -)W(=O)Me3] Prepared by Direct Methylation of [(≡Si - O -)W(=O)Cl3], a Catalyst for Cycloalkane Metathesis and Transformation of Ethylene to Propylene

    KAUST Repository

    Hamieh, Ali Imad Ali

    2015-04-03

    The silica-supported tungsten oxo-trimethyl complex [(≡Si - O -)W(=O)Me3] was synthesized using a novel SOMC synthetic approach. By grafting the inexpensive stable compound WOCl4 on the surface of silica, partially dehydroxylated at 700 °C (SiO2-700), a well-defined monopodal surface complex [(≡Si - O -)W(=O)Cl3] was produced. The supported complex directly methylated with ZnMe2 and transformed into [(≡Si - O -)W(=O)Me3], which we fully characterized by microanalysis, IR, mass balance and SS NMR (1H, 13C, 1H-13C HETCOR, 1H-1H DQ and TQ). [(≡Si - O)W(=O)Me3] has two conformational isomers on the surface at room temperature. The conversion of one to the other was observed at 318 K by variable-temperature 13C CP/MAS and 1H spin echo MAS solid-state NMR; this was also confirmed by NMR and DFT calculations. [(≡Si - O)W(=O)Me3] was found to be active in cyclooctane metathesis and to have a wide distribution range in ring-contracted and ring-expanded products. In addition, [(≡Si - O)W(=O)Me3] proved to be highly active for selective transformation of ethylene to propylene compared to other silica-supported organometallic complexes. (Chemical Equation Presented). © 2015 American Chemical Society.

  2. Bacteriophages as indicators of faecal pollution and enteric ...

    Science.gov (United States)

    Bacteriophages are an attractive alternative to fecal indicator bacteria (FIB), particularly as surrogates of enteric virus fate and transport due to their closer morphological and biological properties compared to FIB. Based on a meta-analysis of published data, we summarize concentrations of coliphages (F+ and somatic), Bacteroides spp. and enterococci bacteriophages (phages) in human waste, non-human waste, fresh and marine waters as well as removal through wastewater treatment processes. We also provide comparisons with FIB and enteric viruses whenever possible. Lastly, we examine fate and transport characteristics in the environment and provide an overview of the methods available for detection and enumeration of bacteriophages. In summary, concentrations of FIB bacteriophages in various sources were consistently lower than FIB, but more reflective of infectious enteric virus levels. Our investigation supports use of bacteriophages as viral surrogates especially for wastewater treatment processes, while additional research is needed to clarify their utility as indicators of viral fate and transport in the ambient water. Describes concentrations and removal through environmental and engineered systems of bacteriophages, fecal indicator bacteria and viral pathogens.

  3. Bacteriophages as Bactericides in Plant Protection

    Directory of Open Access Journals (Sweden)

    Aleksa Obradović

    2009-01-01

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

  4. Bacteriophage T7 DNA polymerase — Sequenase

    Directory of Open Access Journals (Sweden)

    Bin eZhu

    2014-04-01

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

  5. Bacteriophage endolysins: applications for food safety.

    Science.gov (United States)

    Schmelcher, Mathias; Loessner, Martin J

    2016-02-01

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

  6. Montmorillonite-induced Bacteriophage φ6 Disassembly

    Science.gov (United States)

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

    2012-12-01

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

  7. Bacteriophages of Leuconostoc, Oenococcus and Weissella

    Directory of Open Access Journals (Sweden)

    Witold P. Kot

    2014-04-01

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

  8. SU-E-J-115: Correlation of Displacement Vector Fields Calculated by Deformable Image Registration Algorithms with Motion Parameters of CT Images with Well-Defined Targets and Controlled-Motion

    Energy Technology Data Exchange (ETDEWEB)

    Jaskowiak, J; Ahmad, S; Ali, I [University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Alsbou, N [Ohio Northern University, Ada, OH (United States)

    2015-06-15

    Purpose: To investigate correlation of displacement vector fields (DVF) calculated by deformable image registration algorithms with motion parameters in helical axial and cone-beam CT images with motion artifacts. Methods: A mobile thorax phantom with well-known targets with different sizes that were made from water-equivalent material and inserted in foam to simulate lung lesions. The thorax phantom was imaged with helical, axial and cone-beam CT. The phantom was moved with a cyclic motion with different motion amplitudes and frequencies along the superior-inferior direction. Different deformable image registration algorithms including demons, fast demons, Horn-Shunck and iterative-optical-flow from the DIRART software were used to deform CT images for the phantom with different motion patterns. The CT images of the mobile phantom were deformed to CT images of the stationary phantom. Results: The values of displacement vectors calculated by deformable image registration algorithm correlated strongly with motion amplitude where large displacement vectors were calculated for CT images with large motion amplitudes. For example, the maximal displacement vectors were nearly equal to the motion amplitudes (5mm, 10mm or 20mm) at interfaces between the mobile targets lung tissue, while the minimal displacement vectors were nearly equal to negative the motion amplitudes. The maximal and minimal displacement vectors matched with edges of the blurred targets along the Z-axis (motion-direction), while DVF’s were small in the other directions. This indicates that the blurred edges by phantom motion were shifted largely to match with the actual target edge. These shifts were nearly equal to the motion amplitude. Conclusions: The DVF from deformable-image registration algorithms correlated well with motion amplitude of well-defined mobile targets. This can be used to extract motion parameters such as amplitude. However, as motion amplitudes increased, image artifacts increased

  9. Executive Function, Visual Attention and the Cocktail Party Problem in Musicians and Non-Musicians

    Science.gov (United States)

    Clayton, Kameron K.; Swaminathan, Jayaganesh; Yazdanbakhsh, Arash; Zuk, Jennifer; Patel, Aniruddh D.; Kidd, Gerald

    2016-01-01

    The goal of this study was to investigate how cognitive factors influence performance in a multi-talker, “cocktail-party” like environment in musicians and non-musicians. This was achieved by relating performance in a spatial hearing task to cognitive processing abilities assessed using measures of executive function (EF) and visual attention in musicians and non-musicians. For the spatial hearing task, a speech target was presented simultaneously with two intelligible speech maskers that were either colocated with the target (0° azimuth) or were symmetrically separated from the target in azimuth (at ±15°). EF assessment included measures of cognitive flexibility, inhibition control and auditory working memory. Selective attention was assessed in the visual domain using a multiple object tracking task (MOT). For the MOT task, the observers were required to track target dots (n = 1,2,3,4,5) in the presence of interfering distractor dots. Musicians performed significantly better than non-musicians in the spatial hearing task. For the EF measures, musicians showed better performance on measures of auditory working memory compared to non-musicians. Furthermore, across all individuals, a significant correlation was observed between performance on the spatial hearing task and measures of auditory working memory. This result suggests that individual differences in performance in a cocktail party-like environment may depend in part on cognitive factors such as auditory working memory. Performance in the MOT task did not differ between groups. However, across all individuals, a significant correlation was found between performance in the MOT and spatial hearing tasks. A stepwise multiple regression analysis revealed that musicianship and performance on the MOT task significantly predicted performance on the spatial hearing task. Overall, these findings confirm the relationship between musicianship and cognitive factors including domain-general selective attention and

  10. Evaluation of a spasmolytic cocktail to prevent radial artery spasm during coronary procedures.

    Science.gov (United States)

    Kiemeneij, Ferdinand; Vajifdar, Bhavesh U; Eccleshall, Simon C; Laarman, GertJan; Slagboom, Ton; van der Wieken, Ron

    2003-03-01

    Radial artery spasm is a frequent complication of the transradial approach for coronary angiography and angioplasty. Recently, we have been able to quantify spasm using the automatic pullback device. The objective of this study was to assess the efficacy of an intra-arterial vasodilating cocktail in reducing the incidence and severity of radial artery spasm. A hundred patients undergoing coronary procedures via the radial artery were divided into two groups of 50 each. Patients in group A received intra-arterial cocktail (5 mg of verapamil plus 200 micro g nitroglycerine in 10 ml of normal saline), while patients in group B did not receive any vasodilating drug. The pullback device was used for sheath removal at the end of the procedure. Seven (14%) patients in group A experienced pain (i.e., pain score of III-V) during automatic sheath removal, as compared to 17 (34%) in group B (P = 0.019). The mean pain score was significantly lower in group A than in group B (1.7 +/- 0.94 vs. 2.08 +/- 1.07; P = 0.03). The maximal pullback force (MPF) was also significantly lower for group A (0.53 +/- 0.52 kg; range, 0.10-3.03 kg) as compared to group B (0.76 +/- 0.45 kg; range, 0.24-1.99 kg; P = 0.013). Only 4 (8%) patients in group A had an MPF value greater than 1.0 kg, suggesting the presence of significant radial artery spasm, as opposed to 11 (22%) in group B (P = 0.029). Administration of an intra-arterial vasodilating cocktail prior to sheath insertion reduces the occurrence and severity of radial artery spasm.

  11. Development of a mouse monoclonal antibody cocktail for post-exposure rabies prophylaxis in humans.

    Directory of Open Access Journals (Sweden)

    Thomas Müller

    Full Text Available As the demand for rabies post-exposure prophylaxis (PEP treatments has increased exponentially in recent years, the limited supply of human and equine rabies immunoglobulin (HRIG and ERIG has failed to provide the required passive immune component in PEP in countries where canine rabies is endemic. Replacement of HRIG and ERIG with a potentially cheaper and efficacious alternative biological for treatment of rabies in humans, therefore, remains a high priority. In this study, we set out to assess a mouse monoclonal antibody (MoMAb cocktail with the ultimate goal to develop a product at the lowest possible cost that can be used in developing countries as a replacement for RIG in PEP. Five MoMAbs, E559.9.14, 1112-1, 62-71-3, M727-5-1, and M777-16-3, were selected from available panels based on stringent criteria, such as biological activity, neutralizing potency, binding specificity, spectrum of neutralization of lyssaviruses, and history of each hybridoma. Four of these MoMAbs recognize epitopes in antigenic site II and one recognizes an epitope in antigenic site III on the rabies virus (RABV glycoprotein, as determined by nucleotide sequence analysis of the glycoprotein gene of unique MoMAb neutralization-escape mutants. The MoMAbs were produced under Good Laboratory Practice (GLP conditions. Unique combinations (cocktails were prepared, using different concentrations of the MoMAbs that were capable of targeting non-overlapping epitopes of antigenic sites II and III. Blind in vitro efficacy studies showed the MoMab cocktails neutralized a broad spectrum of lyssaviruses except for lyssaviruses belonging to phylogroups II and III. In vivo, MoMAb cocktails resulted in protection as a component of PEP that was comparable to HRIG. In conclusion, all three novel combinations of MoMAbs were shown to have equal efficacy to HRIG and therefore could be considered a potentially less expensive alternative biological agent for use in PEP and prevention of

  12. Modeling Response to Advertising and Pricing Changes for “V-8” Cocktail Vegetable Juice

    OpenAIRE

    Joseph O. Eastlack, Jr.; Ambar G. Rao

    1986-01-01

    This paper is based on a series of studies undertaken for “V-8” Cocktail Vegetable Juice over a five-year period. The studies were a consequence of management questions regarding the effectiveness of a new advertising campaign, the best media mix for this campaign and the apparent “wear-out” of the advertising copy. The studies included controlled experimentation, estimation of advertising response functions, and exploration of price sensitivity following major price increases by “V-8.” It wa...

  13. Variations in the usage and composition of a radial cocktail during radial access coronary angiography procedures.

    LENUS (Irish Health Repository)

    Pate, G

    2011-10-01

    A survey was conducted of medication administered during radial artery cannulation for coronary angiography in 2009 in Ireland; responses were obtained for 15 of 20 centres, in 5 of which no radial access procedures were undertaken. All 10 (100%) centres which provided data used heparin and one or more anti-spasmodics; verapamil in 9 (90%), nitrate in 1 (10%), both in 2 (20%). There were significant variations in the doses used. Further work needs to be done to determine the optimum cocktail to prevent radial artery injury following coronary angiography.

  14. Bacteriophages limit the existence conditions for conjugative plasmids.

    Science.gov (United States)

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

    2015-06-02

    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. Conjugative plasmids are infectious loops of DNA capable of transmitting DNA between bacterial cells and between species. Because plasmids often carry extra genes that allow bacteria to live in otherwise-inhospitable environments, their dynamics are central to understanding bacterial adaptive evolution. The plasmid-bacterium interaction has typically been studied in isolation, but in natural bacterial communities, bacteriophages, viruses that infect bacteria, are ubiquitous. Using experiments, mathematical models, and computer simulations we show that bacteriophages drive plasmid dynamics through their ecological and evolutionary effects on bacteria and ultimately

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

    Science.gov (United States)

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

    2013-02-22

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

  16. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Science.gov (United States)

    2010-07-01

    ... 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. ...

  17. Human mast cell mediator cocktail excites neurons in human and guinea-pig enteric nervous system.

    Science.gov (United States)

    Schemann, M; Michel, K; Ceregrzyn, M; Zeller, F; Seidl, S; Bischoff, S C

    2005-04-01

    Neuroimmune interactions are an integral part of gut physiology and involved in the pathogenesis of inflammatory and functional bowel disorders. Mast cells and their mediators are important conveyors in the communication from the innate enteric immune system to the enteric nervous system (ENS). However, it is not known whether a mediator cocktail released from activated human mast cells affects neural activity in the ENS. We used the Multi-Site Optical Recording Technique to image single cell activity in guinea-pig and human ENS after application of a mast cell mediator cocktail (MCMC) that was released from isolated human intestinal mucosa mast cells stimulated by IgE-receptor cross-linking. Local application of MCMC onto individual ganglia evoked an excitatory response consisting of action potential discharge. This excitatory response occurred in 31%, 38% or 11% neurons of guinea-pig submucous plexus, human submucous plexus, or guinea-pig myenteric plexus, respectively. Compound action potentials from nerve fibres or fast excitatory synaptic inputs were not affected by MCMC. This study demonstrates immunoneural signalling in the human gut and revealed for the first time that an MCMC released from stimulated human intestinal mast cells induces excitatory actions in the human and guinea-pig ENS.

  18. The edible cocktail: the effect of sugar and alcohol impregnation on the crunchiness of fruit

    Directory of Open Access Journals (Sweden)

    Scholten Elke

    2012-06-01

    Full Text Available Abstract Background Vacuum impregnation is seen as a valuable technique for flavor pairing in the catering industry. One of the applications of this technique is the creation of edible cocktails by impregnating fruits with liquors, leading to an interplay of different flavors. However, the effect of the impregnation of sugar and alcohol into the fruit will affect the texture of the fruit and therefore its crunchiness. Thus, the positive effect of flavor pairing might be inhibited by a negative effect in texture changes. Results This investigation focused on the change in crunchiness as a result of the impregnation of different sugar and alcohol containing solutions. When hypotonic solutions were used, the impregnation resulted in the rupture of the cells, thereby leading to a decrease in crunchiness. When hypertonic solutions were used, the cells shrunk, which also resulted in a decrease in crunchiness. Isotonic solutions resulted in crunchiness comparable to its fresh version. When alcohol was used, the crunchiness decreased at all concentrations investigated. Conclusions Crunchiness of fruit can only be maintained when impregnated with isotonic sugar solutions. When the sugar or alcohol content deviates from that in the fruit, impregnation of these liquids will lead to a decrease in crunchiness. This has consequences for the creation of edible cocktails: for an optimal crunchiness, the sugar content of the impregnation liquid has to be equal to the sugar content of the fruit or vegetable.

  19. Molecular Characterization of the Monoclonal Antibodies Composing ZMAb: A Protective Cocktail Against Ebola Virus

    Science.gov (United States)

    Audet, Jonathan; Wong, Gary; Wang, Han; Lu, Guangwen; Gao, George F.; Kobinger, Gary; Qiu, Xiangguo

    2014-01-01

    Ebola virus (EBOV) causes severe viral hemorrhagic fever in humans and non-human primates, with a case fatality rate of up to 88% in human outbreaks. Over the past 3 years, monoclonal antibody (mAb) cocktails have demonstrated high efficacy as treatments against EBOV infection. One such cocktail is ZMAb, which consists of three mouse antibodies, 1H3, 2G4, and 4G7. Here, we present the epitope binding properties of mAbs 1H3, 2G4, and 4G7. We showed that these antibodies have different variable region sequences, suggesting that the individual mAbs are not clonally related. All three antibodies were found to neutralize EBOV variant Mayinga. Additionally, 2G4 and 4G7 were shown to cross-inhibit each other in vitro and select for an escape mutation at the same position on the EBOV glycoprotein (GP), at amino acid 508. 1H3 selects an escape mutant at amino acid 273 on EBOV GP. Surface plasmon resonance studies showed that all three antibodies have dissociation constants on the order of 10−7. In combination with previous studies evaluating the binding sites of other protective antibodies, our results suggest that antibodies targeting the GP1-GP2 interface and the glycan cap are often selected as efficacious antibodies for post-exposure interventions against EBOV. PMID:25375093

  20. Visual input enhances selective speech envelope tracking in auditory cortex at a "cocktail party".

    Science.gov (United States)

    Zion Golumbic, Elana; Cogan, Gregory B; Schroeder, Charles E; Poeppel, David

    2013-01-23

    Our ability to selectively attend to one auditory signal amid competing input streams, epitomized by the "Cocktail Party" problem, continues to stimulate research from various approaches. How this demanding perceptual feat is achieved from a neural systems perspective remains unclear and controversial. It is well established that neural responses to attended stimuli are enhanced compared with responses to ignored ones, but responses to ignored stimuli are nonetheless highly significant, leading to interference in performance. We investigated whether congruent visual input of an attended speaker enhances cortical selectivity in auditory cortex, leading to diminished representation of ignored stimuli. We recorded magnetoencephalographic signals from human participants as they attended to segments of natural continuous speech. Using two complementary methods of quantifying the neural response to speech, we found that viewing a speaker's face enhances the capacity of auditory cortex to track the temporal speech envelope of that speaker. This mechanism was most effective in a Cocktail Party setting, promoting preferential tracking of the attended speaker, whereas without visual input no significant attentional modulation was observed. These neurophysiological results underscore the importance of visual input in resolving perceptual ambiguity in a noisy environment. Since visual cues in speech precede the associated auditory signals, they likely serve a predictive role in facilitating auditory processing of speech, perhaps by directing attentional resources to appropriate points in time when to-be-attended acoustic input is expected to arrive.

  1. Neuroprotection by Cocktails of Dietary Antioxidants under Conditions of Nerve Growth Factor Deprivation.

    Science.gov (United States)

    Amara, Flavio; Berbenni, Miluscia; Fragni, Martina; Leoni, Giampaolo; Viggiani, Sandra; Ippolito, Vita Maria; Larocca, Marilena; Rossano, Rocco; Alberghina, Lilia; Riccio, Paolo; Colangelo, Anna Maria

    2015-01-01

    Dietary antioxidants may be useful in counteracting the chronic inflammatory status in neurodegenerative diseases by reducing oxidative stress due to accumulation of reactive oxygen species (ROS). In this study, we newly described the efficacy of a number of dietary antioxidants (polyphenols, carotenoids, thiolic compounds, and oligoelements) on viability of neuronal PC12 cells following Nerve Growth Factor (NGF) deprivation, a model of age-related decrease of neurotrophic support that triggers neuronal loss. Neuroprotection by antioxidants during NGF deprivation for 24 h was largely dependent on their concentrations: all dietary antioxidants were able to efficiently support cell viability by reducing ROS levels and restoring mitochondrial function, while preserving the neuronal morphology. Moreover, ROS reduction and neuroprotection during NGF withdrawal were also achieved with defined cocktails of 3-6 different antioxidants at concentrations 5-60 times lower than those used in single treatments, suggesting that their antioxidant activity was preserved also at very low concentrations. Overall, these data indicate the beneficial effects of antioxidants against oxidative stress induced by decreased NGF availability and suggest that defined cocktails of dietary factors at low concentrations might be a suitable strategy to reduce oxidative damage in neurodegenerative diseases, while limiting possible side effects.

  2. Regulation of adipogenesis by medium-chain fatty acids in the absence of hormonal cocktail.

    Science.gov (United States)

    Yang, Jeong-Yeh; Della-Fera, Mary Anne; Rayalam, Srujana; Park, Hea Jin; Ambati, Suresh; Hausman, Dorothy B; Hartzell, Diane L; Baile, Clifton A

    2009-07-01

    We report here that octanoate and decanoate, 8-carbon and 10-carbon medium-chain fatty acids (MCFA), decreased adipogenesis in 3T3-L1 preadipocytes when treated with standard hormonal cocktail, but increased adipogenesis in a dose-dependent manner (with decanoate being more effective) when treated with basal media. Addition of dexamethasone to basal medium with either octanoate or decanoate further increased adipogenesis. In order to understand the adipogenic effects of MCFA in the absence of standard hormonal cocktail, postconfluent 3T3-L1 preadipocytes were treated with octanoate or decanoate, and the change in the expression of several adipogenic transcription factors and enzymes was investigated using real-time RT-PCR. Octanoate and decanoate up-regulated the mRNA expression of peroxisome-proliferator-activated receptor (PPAR) gamma, CCAAT/enhancer-binding protein (C/EBP) alpha, fatty-acid-binding protein, sterol-regulatory element binding protein 1c, lipoprotein lipase and hormone-sensitive lipase, and the protein expression of PPARgamma and C/EBPalpha, with decanoate being more effective. Moreover, the PPARgamma antagonist GW9662 inhibited MCFA-induced lipid accumulation by about 50%. Decanoate and octanoate, to a lesser degree, increased lipid accumulation, which was associated with an increase in glycerol-3-phosphate dehydrogenase activity. These results show that octanoate and decanoate may stimulate differentiation of preadipocytes, at least in part, by their influence on the expression of PPARgamma and other adipocyte-specific factors.

  3. Neuroprotection by Cocktails of Dietary Antioxidants under Conditions of Nerve Growth Factor Deprivation

    Science.gov (United States)

    Amara, Flavio; Berbenni, Miluscia; Fragni, Martina; Leoni, Giampaolo; Viggiani, Sandra; Ippolito, Vita Maria; Larocca, Marilena; Rossano, Rocco; Alberghina, Lilia; Riccio, Paolo; Colangelo, Anna Maria

    2015-01-01

    Dietary antioxidants may be useful in counteracting the chronic inflammatory status in neurodegenerative diseases by reducing oxidative stress due to accumulation of reactive oxygen species (ROS). In this study, we newly described the efficacy of a number of dietary antioxidants (polyphenols, carotenoids, thiolic compounds, and oligoelements) on viability of neuronal PC12 cells following Nerve Growth Factor (NGF) deprivation, a model of age-related decrease of neurotrophic support that triggers neuronal loss. Neuroprotection by antioxidants during NGF deprivation for 24 h was largely dependent on their concentrations: all dietary antioxidants were able to efficiently support cell viability by reducing ROS levels and restoring mitochondrial function, while preserving the neuronal morphology. Moreover, ROS reduction and neuroprotection during NGF withdrawal were also achieved with defined cocktails of 3–6 different antioxidants at concentrations 5–60 times lower than those used in single treatments, suggesting that their antioxidant activity was preserved also at very low concentrations. Overall, these data indicate the beneficial effects of antioxidants against oxidative stress induced by decreased NGF availability and suggest that defined cocktails of dietary factors at low concentrations might be a suitable strategy to reduce oxidative damage in neurodegenerative diseases, while limiting possible side effects. PMID:26236423

  4. Sequence variability of Campylobacter temperate bacteriophages

    Directory of Open Access Journals (Sweden)

    Ng Lai-King

    2008-03-01

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

  5. Bacteriophage Infection of Model Metal Reducing Bacteria

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2014-03-26

    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.

  7. Defined enzyme cocktail from the anaerobic fungus Orpinomyces sp. strain C1A effectively releases sugars from pretreated corn stover and switchgrass

    Science.gov (United States)

    Morrison, Jessica M.; Elshahed, Mostafa S.; Youssef, Noha H.

    2016-01-01

    The anaerobic fungus Orpinomyces strain C1A is capable of growth on various types of lignocellulosic substrates, and harbors an impressive reservoir of carbohydrate active enzymes (CAZymes). Using a minimum enzyme cocktail strategy, we constituted a four-component lignocellulolytic cocktail derived from highly transcribed C1A, and evaluated its efficacy against pretreated corn stover and switchgrass. Hydrolysis yields ranged between 65–77.4%, depending on the lignocellulosic substrate and pretreatment applied. Addition of a highly expressed anaerobic fungal swollenin improved hydrolysis yields by up to 7%. Compared to the commercial cocktail CTec2, these anaerobic fungal cocktails provided comparable or slightly lower hydrolysis yields. Further, the differences in efficacy between commercial and anaerobic cocktails were often only realized after extended (168 hr) incubations. Under certain conditions, the hydrolysis yields of the anaerobic fungal cocktail was slightly superior to that realized by CTec2. We attribute the observed high hydrolysis yields to the high specific activity and affinity of the individual enzymes of the cocktail, as well as the high level of synergy and multi-functionality observed in multiple components. Collectively, this effort provides a novel platform for constructing highly effective enzymes for biofuel production and represents the first lignocellulolytic enzyme cocktail created from anaerobic fungal enzymes. PMID:27381262

  8. Isolation and Host Range of Bacteriophage with Lytic Activity against Methicillin-Resistant Staphylococcus aureus and Potential Use as a Fomite Decontaminant.

    Directory of Open Access Journals (Sweden)

    Kyle C Jensen

    Full Text Available Staphylococcus aureus (SA is a commensal bacterium and opportunistic pathogen commonly associated with humans and is capable of causing serious disease and death including sepsis, pneumonia, and meningitis. Methicillin-resistant SA (MRSA isolates are typically resistant to many available antibiotics with the common exception of vancomycin. The presence of vancomycin resistance in some SA isolates combined with the current heavy use of vancomycin to treat MRSA infections indicates that MRSA may achieve broad resistance to vancomycin in the near future. New MRSA treatments are clearly needed. Bacteriophages (phages are viruses that infect bacteria, commonly resulting in death of the host bacterial cell. Phage therapy entails the use of phage to treat or prevent bacterial infections. In this study, 12 phages were isolated that can replicate in human SA and/or MRSA isolates as a potential way to control these infections. 5 phage were discovered through mitomycin C induction of prophage and 7 others as extracellular viruses. Primary SA strains were also isolated from environmental sources to be used as tools for phage discovery and isolation as well as to examine the target cell host range of the phage isolates by spot testing. Primary isolates were tested for susceptibility to oxacillin in order to determine which were MRSA. Experiments were performed to assess the host range and killing potential of newly discovered phage, and significant reductions in bacterial load were detected. We explored the utility of some phage to decontaminate fomites (glass and cloth and found a significant reduction in colony forming units of MRSA following phage treatment, including tests of a phage cocktail against a cocktail of MRSA isolates. Our findings suggest that phage treatment can be used as an effective tool to decontaminate human MRSA from both hard surfaces and fabrics.

  9. Bacteriophage based probes for pathogen detection.

    Science.gov (United States)

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

    2012-08-01

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

  10. Bacteriophages and its applications: an overview.

    Science.gov (United States)

    Sharma, Sonika; Chatterjee, Soumya; Datta, Sibnarayan; Prasad, Rishika; Dubey, Dharmendra; Prasad, Rajesh Kumar; Vairale, Mohan G

    2017-01-01

    Bacteriophages (or phages), the most abundant viral entity of the planet, are omni-present in all the ecosystems. On the basis of their unique characteristics and anti-bacterial property, phages are being freshly evaluated taxonomically. Phages replicate inside the host either by lytic or lysogenic mode after infecting and using the cellular machinery of a bacterium. Since their discovery by Twort and d'Herelle in the early 1900s, phage became an important agent for combating pathogenic bacteria in clinical treatments and its related research gained momentum. However, due to recent emergence of bacterial resistance on antibiotics, applications of phage (phage therapy) become an inevitable option of research. Phage particles become popular as a biotechnological tool and treatment of pathogenic bacteria in a range of applied areas. However, there are few concerns over the application of phage-based solutions. This review deals with the updated phage taxonomy (ICTV 2015 Release and subsequent revision) and phage biology and the recent development of its application in the areas of biotechnology, biosensor, therapeutic medicine, food preservation, aquaculture diseases, pollution remediation, and wastewater treatment and issues related with limitations of phage-based remedy.

  11. DNA packaging in bacteriophage: is twist important?

    Science.gov (United States)

    Spakowitz, Andrew James; Wang, Zhen-Gang

    2005-06-01

    We study the packaging of DNA into a bacteriophage capsid using computer simulation, specifically focusing on the potential impact of twist on the final packaged conformation. We perform two dynamic simulations of packaging a polymer chain into a spherical confinement: one where the chain end is rotated as it is fed, and one where the chain is fed without end rotation. The final packaged conformation exhibits distinct differences in these two cases: the packaged conformation from feeding with rotation exhibits a spool-like character that is consistent with experimental and previous theoretical work, whereas feeding without rotation results in a folded conformation inconsistent with a spool conformation. The chain segment density shows a layered structure, which is more pronounced for packaging with rotation. However, in both cases, the conformation is marked by frequent jumps of the polymer chain from layer to layer, potentially influencing the ability to disentangle during subsequent ejection. Ejection simulations with and without Brownian forces show that Brownian forces are necessary to achieve complete ejection of the polymer chain in the absence of external forces.

  12. Hurdles in bacteriophage therapy: deconstructing the parameters.

    Science.gov (United States)

    Tsonos, Jessica; Vandenheuvel, Dieter; Briers, Yves; De Greve, Henri; Hernalsteens, Jean-Pierre; Lavigne, Rob

    2014-07-16

    Bacterial infections in animals impact our food production, leading to economic losses due to food rejection and the need for preventive and curative measures. Since the onset of the antibiotic era, the rise of antibiotic-resistant pathogens is causing scares in health care and food producing facilities worldwide. In the search of new therapeutics, re-evaluation of bacteriophage (phage) therapy, using naturally occurring bacterial viruses to tackle infections, is gaining interest. Many studies report about phage therapy success, showing the value and power of these natural viruses. Although phages carry some interesting traits and their basic biology is now well understood, this review argues that phage therapy has not revealed all of its secrets and many parameters remain understudied, making the outcome of phage therapy highly variable depending on the disease incidence. These difficulties include poorly understood mechanisms of phage penetration and distribution throughout the body, the variable expression and accessibility of phage receptors on the bacterial host in in vivo conditions and the unusual (non-linear) phage pharmacokinetics. These parameters are not easily measured in realistic in vivo settings, but are nevertheless important hurdles to overcome the high variability of phage therapy trials. This critical approach is in accordance with Goethe's statement; "Difficulties increase the nearer we get to the goal". However, since the importance of the goal itself also rises, both difficulties and goal justify the need for additional in depth research in this domain. Copyright © 2013 Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Pristas Peter

    2014-06-01

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

  14. Antibacterial bioagents based on principles of bacteriophage biology: an overview.

    Science.gov (United States)

    Knoll, Bettina M; Mylonakis, Eleftherios

    2014-02-01

    Bacteriophages were discovered almost a century ago. With the advent of antibiotics, the use of bacteriophages for treatment of infections fell out of favor in Western medicine. In light of the rise of antibiotic resistance, phages and their products (lysins) are rediscovered as antibacterial bioagents. This overview summarizes principles of phage biology and their translation for therapeutic and preventive applications. Examples are presented to highlight their therapeutic promise for prophylaxis and treatment of bacterial infections including multidrug-resistant organisms in humans and animals, and their use as decontaminants of food supplies and environments. Besides research on the in vivo behavior of phages and lysins, dialogues between researchers and regulatory agencies are necessary to publish guidelines for bacteriophage manufacturing and formulation for human use. Only well-designed, double-blind randomized controlled trials will determine if phages and lysins are safe and effective adjuncts or alternatives to antibiotic therapy for infections with multidrug-resistant organisms.

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

    Science.gov (United States)

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

    2014-01-01

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

  16. Engineered enzymatically active bacteriophages and methods of uses thereof

    Science.gov (United States)

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

    2012-05-22

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

  17. Bacteriophages of Soft Rot Enterobacteriaceae-a minireview.

    Science.gov (United States)

    Czajkowski, Robert

    2016-01-01

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

  18. Bacteriophage inspired antibiotics discovery against infection involved biofilm.

    Science.gov (United States)

    Fan, Xiangyu; Li, Wu; Zheng, Fei; Xie, Jianping

    2013-01-01

    Bacterial biofilm profoundly influences the fate of bacteria within and the outcome of related infection, and is closely associated with antibiotics resistance and bacterial persistence. Bacteriophages represent a new promising alternative to combat biofilm-related infection. The interplay between phages and biofilms is complex. Some phages or their components can inhibit the host bacteria biofilm via diverse mechanisms, while other phages can facilitate the host biofilm formation through phage-mediated lysis and extracellular DNA release. In this paper, we summarize the role of bacteriophages in the biofilm formation, and the application of phages to the control of bacterial persisters and infectious biofilms, in particular, the phage-inspired antibiotics discovery.

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

    Science.gov (United States)

    Hodyra, Katarzyna; Dąbrowska, Krystyna

    2015-04-01

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

  20. Efficacy of multimodal cocktail periarticular injection with or without steroid in total knee arthroplasty

    Institute of Scientific and Technical Information of China (English)

    YUE De-bo; WANG Bai-liang; LIU Kun-peng; GUO Wan-shou

    2013-01-01

    Background Multimodal cocktail periarticular injection (MCPI) with a large volume of low concentration local anesthetics,adrenaline,and anti-inflammatory agents such as non-steroidal anti-inflammatory drug or steroids have shown good pain control and improvement in range of motion after surgery.This study compares the efficacy of pain control after total knee arthroplasty,using multimodal cocktail periarticular injection with steroid or without steroid.Methods This is a prospective,double-blinded,randomized and control study.Seventy-two patients with osteoarthritis that met clinical criteria for total knee arthroplasty were recruited into the study,and were randomized to receive either multimodal cocktail periarticular injection with steroid or without steroid.Pain was assessed by visual analogue scale (VAS) at preoperative and postoperative at rest,and during activity.The range of motion was recorded preoperatively and postoperatively.The amount of daily and cumulative morphine consumption were measured by patient-controlled analgesia in the first 72 hours postoperatively.The duration of celecoxib usage was also recorded at the last follow-up.Results There were no differences between the non-steroid and steroid groups with regard to VAS at rest and during activity,or range of motion,at any postoperative observation time.The postoperative Knee Society Knee Score in the steroid group improved significantly as compared with that in non-steroid group at the one-month (84.1±13.1 and 65.9±12.1; P <0.0045),three-month follow-up (90.2±16.3 and 72.5±16.6; P <0.0027),but after postoperative six-month the Knee Society Knee Score showed no significant difference between the groups.There was no significant difference in consumption of the morphine about daily or total consumption within 72 hours between the two groups.The duration of celecoxib usage in patients in the steroid group was significantly shorter than that in the non-steroid group ((7.2±0.7) compared with

  1. 结构明确的可降解醛基功能化含糖纳米微球的制备%PREPARATION OF WELL-DEFINED AND DEGRADABLE ALDEHYDE-FUNCTIONALIZED GLYCOPOLYMERIC NANOSPHERES

    Institute of Scientific and Technical Information of China (English)

    肖乃玉; 钟乐; 翟万京; 白卫东

    2012-01-01

    composition was determined by taking the ratio of peak areas of aldehyde protons of IVDG to that of of BMDO. It is observed that the mole fraction of BMDO was less in copolymers as compared to that in the initial feed. The result was mostly because the BMDO radical is neighbor to two electron-rich oxygen atoms so as to have lower reactivity as compared to IVDG radical. The copolymer compositions and structural characterization were obtained from 'H-NMR spectroscopy. Degradation behavior of these copolymers was also investigated. Removal of protective isopropylidene groups from the sugar residue in poly( BMDO-co-IVDG) was carried out quantitatively using 88% formic acid at room temperature, yielding a novel amphiphilic copolymer containing both galactopyranose and aldehyde functionalities. These amphiphilic glycopolymers self-assembled into well-defined degradable and biocompatible aldehyde-functionalized polymeric nanospheres in aqueous solutions without recourse to any surfactant. The nanospheres obtained from the resultant glycopolymer are possible to be used as nanoparticle targeted drug-delivery system.

  2. Safety analysis of a Russian phage cocktail: From MetaGenomic analysis to oral application in healthy human subjects

    Energy Technology Data Exchange (ETDEWEB)

    McCallin, Shawna, E-mail: semccallin@yahoo.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Alam Sarker, Shafiqul, E-mail: sasarker@icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); Barretto, Caroline, E-mail: Caroline.Barretto@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Sultana, Shamima, E-mail: shamima@icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); Berger, Bernard, E-mail: bernard.berger@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Huq, Sayeda, E-mail: sayeeda@mail.icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); Krause, Lutz, E-mail: ltz.krause@gmail.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Bibiloni, Rodrigo, E-mail: Rodrigo.Bibiloni@agresearch.co.nz [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Schmitt, Bertrand, E-mail: bertrand.schmitt@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Reuteler, Gloria, E-mail: gloria.reuteler@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Brüssow, Harald, E-mail: harald.bruessow@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland)

    2013-09-01

    Phage therapy has a long tradition in Eastern Europe, where preparations are comprised of complex phage cocktails whose compositions have not been described. We investigated the composition of a phage cocktail from the Russian pharmaceutical company Microgen targeting Escherichia coli/Proteus infections. Electron microscopy identified six phage types, with numerically T7-like phages dominating over T4-like phages. A metagenomic approach using taxonomical classification, reference mapping and de novo assembly identified 18 distinct phage types, including 7 genera of Podoviridae, 2 established and 2 proposed genera of Myoviridae, and 2 genera of Siphoviridae. De novo assembly yielded 7 contigs greater than 30 kb, including a 147-kb Myovirus genome and a 42-kb genome of a potentially new phage. Bioinformatic analysis did not reveal undesired genes and a small human volunteer trial did not associate adverse effects with oral phage exposure. - Highlights: • We analyzed the composition of a commercial Russian phage cocktail. • The cocktail consists of at least 10 different phage genera. • No undesired genes were detected. • No adverse effects were seen upon oral application in a small human clinical trial.

  3. Cocktail-Dosing Microdialysis Study to Simultaneously Assess Delivery of Multiple Organic-Cationic Drugs to the Brain.

    Science.gov (United States)

    Kitamura, Atsushi; Okura, Takashi; Higuchi, Kei; Deguchi, Yoshiharu

    2016-02-01

    Brain microdialysis is a powerful tool to estimate brain-to-plasma unbound concentration ratio at the steady state (Kp,uu) of compounds by direct measurement of the unbound concentration in brain interstitial fluid. Here, we evaluated a method to estimate Kp,uu values of multiple organic-cationic drugs simultaneously, by means of brain microdialysis combined with cocktail dosing. Five cationic drugs (diphenhydramine, memantine, oxycodone, pyrilamine, and tramadol), substrates of the proton-coupled organic cation antiport system, were selected as model drugs, and compared under single-dosing and cocktail-dosing conditions. We selected doses of the drugs at which no significant drug-drug interaction occurs at the proton-coupled organic cation antiport system in the blood-brain barrier (BBB). This was confirmed by uptake studies in hCMEC/D3 cells, an in vitro BBB model. The Kp,uu values after cocktail administration were in the range of 1.8-5.2, and were in good agreement with those after single administration. These results suggest that the microdialysis method with cocktail dosing is suitable to estimate Kp,uu values of several cationic drugs simultaneously, if there is no drug-drug interaction during BBB transport. The method could be useful for evaluating drug candidates with high Kp,uu values at an early stage in the development of central nervous system-acting drugs.

  4. Coverage of diarrhoea-associated Escherichia coli isolates from different origins with two types of phage cocktails

    Science.gov (United States)

    Bourdin, Gilles; Navarro, Armando; Sarker, Shafiqul A; Pittet, Anne-C; Qadri, Firdausi; Sultana, Shamima; Cravioto, Alejandro; Talukder, Kaisar A; Reuteler, Gloria; Brüssow, Harald

    2014-01-01

    Eighty-nine T4-like phages from our phage collection were tested against four collections of childhood diarrhoea-associated Escherichia coli isolates representing different geographical origins (Mexico versus Bangladesh), serotypes (69 O, 27 H serotypes), pathotypes (ETEC, EPEC, EIEC, EAEC, VTEC, Shigella), epidemiological settings (community and hospitalized diarrhoea) and years of isolation. With a cocktail consisting of 3 to 14 T4-like phages, we achieved 54% to 69% coverage against predominantly EPEC isolates from Mexico, 30% to 53% against mostly ETEC isolates from a prospective survey in Bangladesh, 24% to 61% against a mixture of pathotypes isolated from hospitalized children in Bangladesh, and 60% coverage against Shigella isolates. In comparison a commercial Russian phage cocktail containing a complex mixture of many different genera of coliphages showed 19%, 33%, 50% and 90% coverage, respectively, against the four above-mentioned collections. Few O serotype-specific phages and no broad-host range phages were detected in our T4-like phage collection. Interference phenomena between the phage isolates were observed when constituting larger phage cocktails. Since the coverage of a given T4-like phage cocktail differed with geographical area and epidemiological setting, a phage composition adapted to a local situation is needed for phage therapy approaches against E. coli pathogens. PMID:24528873

  5. Evaluation of the "Kosish Cocktail" in treating severe pain in "Home Care" in Morphine-naïve communities

    Directory of Open Access Journals (Sweden)

    A K Dam

    2010-01-01

    Conclusions: On the basis of this qualitative study, the authors confirm the efficacy and safety of the use of the Kosish cocktail in treating severe pain, and strongly recommend it for newly started hospices, especially for use in the domiciliary set-up.

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

    Science.gov (United States)

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

    2013-09-15

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

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

    Directory of Open Access Journals (Sweden)

    Maud M Swanson

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

  8. Evaluation of new antibiotic cocktails against contaminating bacteria found in allograft tissues.

    Science.gov (United States)

    Serafini, Agnese; Riello, Erika; Trojan, Diletta; Cogliati, Elisa; Palù, Giorgio; Manganelli, Riccardo; Paolin, Adolfo

    2016-12-01

    Contamination of retrieved tissues is a major problem for allograft safety. Consequently, tissue banks have implemented decontamination protocols to eliminate microorganisms from tissues. Despite the widespread adoption of these protocols, few comprehensive studies validating such methods have been published. In this manuscript we compare the bactericidal activity of different antibiotic cocktails at different temperatures against a panel of bacterial species frequently isolated in allograft tissues collected at the Treviso Tissue Bank Foundation, a reference organization of the Veneto Region in Italy that was instituted to select, recover, process, store and distribute human tissues. We were able to identify at least two different formulations capable of killing most of the bacteria during prolonged incubation at 4 °C.

  9. RECHERCHES SUR LE DEVELOPPEMENT DES COCKTAILS AVEC UN POTENTIEL ANTIOXYDANT ELEVE

    Directory of Open Access Journals (Sweden)

    Daniela Istrati

    2010-12-01

    Full Text Available The research aimed to study the influence of the extraction process on the content of antioxidant compounds present in four types of tea and establishing of the optimal conditions for preparation of cocktails in whose composition is combined the beneficial effect of foods rich in antioxidants and vitamins: green tea, exotic fruits, berries and honey. Content of antioxidants, protein, fiber, vitamins and minerals from unfermented tea is supplemented by high concentration of biological active compounds in fruits and honey used. A positive correlation between substances added with significant increase of antioxidant and nutritive potential has been observed. This study confirms that the synergistic action of green tea, fruits and honey allowed obtaining attractive drinks from sensorial point of view and compounds with high antioxidant potential content.

  10. Improvement on sugar cane bagasse hydrolysis using enzymatic mixture designed cocktail.

    Science.gov (United States)

    Bussamra, Bianca Consorti; Freitas, Sindelia; Costa, Aline Carvalho da

    2015-01-01

    The aim of this work was to study cocktail supplementation for sugar cane bagasse hydrolysis, where the enzymes were provided from both commercial source and microorganism cultivation (Trichoderma reesei and genetically modified Escherichia coli), followed by purification. Experimental simplex lattice mixture design was performed to optimize the enzymatic proportion. The response was evaluated through hydrolysis microassays validated here. The optimized enzyme mixture, comprised of T. reesei fraction (80%), endoglucanase (10%) and β-glucosidase (10%), converted, theoretically, 72% of cellulose present in hydrothermally pretreated bagasse, whereas commercial Celluclast 1.5L converts 49.11%±0.49. Thus, a rational enzyme mixture designed by using synergism concept and statistical analysis was capable of improving biomass saccharification.

  11. Immobilization of Active Bacteriophages on Polyhydroxyalkanoate Surfaces.

    Science.gov (United States)

    Wang, Chanchan; Sauvageau, Dominic; Elias, Anastasia

    2016-01-20

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

  12. Bacteriophages and their enzymes in biofilm control.

    Science.gov (United States)

    Chan, Benjamin K; Abedon, Stephen T

    2015-01-01

    Although free-swimming planktonic bacteria historically have been the typical focus of microbiological studies, the natural state of many or most bacteria is one where they instead are associated with surfaces and/or each other. For many pathogenic as well as nuisance bacteria, including biofouling bacteria, it consequently is within the context of this biofilm state that antibacterial strategies must be implemented. For reasons that are not fully understood, however, biofilm-associated bacteria tend to be less susceptible to treatments with standard chemical antibacterial agents than are planktonic bacteria, and this appears to be especially an issue with the use of less-harsh agents such as antibiotics. Within a variety of contexts the development of less- or selectively toxic antibacterial agents capable of clearing biofilms therefore would be welcome. In this review we consider the use of three categories of such agents as anti-biofilm antibacterials. These are lytic viruses of bacteria, that is, bacteriophages, effecting phage-mediated biocontrol of bacteria (a.k.a., phage therapy); purified phage-encoded enzymes that digest bacterial cell-wall material (endolysins or simply lysins); and a second category of phage-encoded enzymes that digest the extracellular polymeric substance (EPS) that are particularly notable components of bacterial biofilms (EPS depolymerases). These agents have been shown to reduce the bacterial density of a diversity of biofilms and, in many cases, tend to be lacking in inherent toxicity against the tissues of animals. Here we consider these phage-based anti-biofilm strategies with emphasis on ecological aspects of their action and with particular consideration of EPS depolymerases.

  13. Selective Attention Enhances Beta-Band Cortical Oscillation to Speech under "Cocktail-Party" Listening Conditions.

    Science.gov (United States)

    Gao, Yayue; Wang, Qian; Ding, Yu; Wang, Changming; Li, Haifeng; Wu, Xihong; Qu, Tianshu; Li, Liang

    2017-01-01

    Human listeners are able to selectively attend to target speech in a noisy environment with multiple-people talking. Using recordings of scalp electroencephalogram (EEG), this study investigated how selective attention facilitates the cortical representation of target speech under a simulated "cocktail-party" listening condition with speech-on-speech masking. The result shows that the cortical representation of target-speech signals under the multiple-people talking condition was specifically improved by selective attention relative to the non-selective-attention listening condition, and the beta-band activity was most strongly modulated by selective attention. Moreover, measured with the Granger Causality value, selective attention to the single target speech in the mixed-speech complex enhanced the following four causal connectivities for the beta-band oscillation: the ones (1) from site FT7 to the right motor area, (2) from the left frontal area to the right motor area, (3) from the central frontal area to the right motor area, and (4) from the central frontal area to the right frontal area. However, the selective-attention-induced change in beta-band causal connectivity from the central frontal area to the right motor area, but not other beta-band causal connectivities, was significantly correlated with the selective-attention-induced change in the cortical beta-band representation of target speech. These findings suggest that under the "cocktail-party" listening condition, the beta-band oscillation in EEGs to target speech is specifically facilitated by selective attention to the target speech that is embedded in the mixed-speech complex. The selective attention-induced unmasking of target speech may be associated with the improved beta-band functional connectivity from the central frontal area to the right motor area, suggesting a top-down attentional modulation of the speech-motor process.

  14. Frankincense derived heavy terpene cocktail boosting breast cancer cell(MDA-MB-231) death in vitro简

    Institute of Scientific and Technical Information of China (English)

    Faruck; Lukmanul; Hakkim; Mohammed; Al-Buloshi; Jamal; Al-Sabahi

    2015-01-01

    Objective: To investigate the anti-cancer effect of frankincense derived heavy oil obtained by Soxhlet extraction method on breast cancer cells(MDA-MB-231), and to study its chemical profile using gas chromatography mass spectrometry analysis.Methods: Hexane was used to extract heavy oil from frankincense resin. Chemical profiling of heavy oil was done using Perkin Elmer Clarus GC system with mass spectrometer. MDA-MB-231 cells were treated with different dilutions(1:1 000, 1:1 500,1:1 750, 1:2 000, 1:2 250, 1:2 500, 1:2 750, 1:3 000, 1:3 250) of heavy oil for 24 h. The cells were observed by using light microscopy. Cell viability was measured by MTT assay.Results: Gas chromatography mass spectrometry chemical profiling of frankincense derived heavy oil revealed the presence of terpenes such as a-pinene(61.56%), a-amyrin(20.6%), b-amyrin(8.1%), b-phellandrene(1.47%) and camphene(1.04%). Heavy terpene cocktail induced significant MDA-MB-231 cell death at each concentration tested. Noticeably, very low concentration of Soxhlet derived heavy terpenes elicits considerable cytotoxicity on MDA-MB-231 cells compared to hydro distillated essential oil derived from frankincense resin.Conclusions: Extracting anti-cancer active principle cocktail by simple Soxhlet method is cost effective and less time consuming. Our in vitro anti-cancer data forms the rationale for us to test heavy terpene complex in breast cancer xenograft model in vivo. Furthermore, fractionation and developing frankincense heavy terpene based breast cancer drug is the major goal of our laboratory.

  15. Frankincense derived heavy terpene cocktail boosting breast cancer cell (MDA-MB-231) deathin vitro

    Institute of Scientific and Technical Information of China (English)

    Faruck Lukmanul Hakkim; Mohammed Al-Buloshi; Jamal Al-Sabahi

    2015-01-01

    Objective:To investigate the anti-cancer effect of frankincense derived heavy oil obtained by Soxhlet extraction method on breast cancer cells (MDA-MB-231), and to study its chemical profile using gas chromatography mass spectrometry analysis. Methods: Hexane was used to extract heavy oil from frankincense resin. Chemical profiling of heavy oil was done using Perkin Elmer Clarus GC system with mass spectrometer.MDA-MB-231 cells were treated with different dilutions (1:1 000, 1:1 500, 1:1 750, 1:2 000, 1:2 250, 1:2 500, 1:2 750, 1:3 000, 1:3 250) of heavy oil for 24 h. The cells were observed by using light microscopy. Cell viability was measured byMTT assay. Results: Gas chromatography mass spectrometry chemical profiling of frankincense derived heavy oil revealed the presence of terpenes such asα-pinene (61.56%),α-amyrin (20.6%),β-amyrin (8.1%),β-phellandrene (1.47%) and camphene (1.04%). Heavy terpene cocktail induced significantMDA-MB-231 cell death at each concentration tested. Noticeably, very low concentration of Soxhlet derived heavy terpenes elicits considerable cytotoxicityon MDA-MB-231cells compared to hydro distillated essential oil derived from frankincense resin. Conclusions: Extracting anti-cancer active principle cocktail by simple Soxhlet method is cost effective and less time consuming. Ourin vitro anti-cancer data forms the rationale for us to test heavy terpene complex in breast cancer xenograft modelin vivo. Furthermore, fractionation and developing frankincense heavy terpene based breast cancer drug is the major goal of our laboratory.

  16. Vibrio cholerae bacteriophage CP-T1: characterization of bacteriophage DNA and restriction analysis.

    Science.gov (United States)

    Guidolin, A; Morelli, G; Kamke, M; Manning, P A

    1984-01-01

    Temperature bacteriophage CP-T1 of Vibrio cholerae has a capsid that is 45 nm in diameter, a contractile tail 65 nm long and 9.5 nm wide, and a baseplate with several spikes or short tail fibers. The linear double-stranded DNA is 43.5 +/- 1.4 kilobases long, and the phage genome is both terminally redundant and partially circularly permuted. The extent of terminal redundancy is ca. 4%, and circular permutation is up to ca. 44%. Circular restriction maps have been constructed for the enzymes HindIII, EcoRI, BamHI, and PstI. By restriction endonuclease and heteroduplex analyses of phage DNA, the presence and location of a site (pac) at which packaging of phage DNA is initiated was established. Images PMID:6328035

  17. Vibrio cholerae bacteriophage CP-T1: characterization of bacteriophage DNA and restriction analysis.

    Science.gov (United States)

    Guidolin, A; Morelli, G; Kamke, M; Manning, P A

    1984-07-01

    Temperature bacteriophage CP-T1 of Vibrio cholerae has a capsid that is 45 nm in diameter, a contractile tail 65 nm long and 9.5 nm wide, and a baseplate with several spikes or short tail fibers. The linear double-stranded DNA is 43.5 +/- 1.4 kilobases long, and the phage genome is both terminally redundant and partially circularly permuted. The extent of terminal redundancy is ca. 4%, and circular permutation is up to ca. 44%. Circular restriction maps have been constructed for the enzymes HindIII, EcoRI, BamHI, and PstI. By restriction endonuclease and heteroduplex analyses of phage DNA, the presence and location of a site (pac) at which packaging of phage DNA is initiated was established.

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

    Science.gov (United States)

    Bronfenbrenner, J

    1927-04-30

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

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

    Science.gov (United States)

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

    2013-07-01

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

  20. Multiple roles of genome-attached bacteriophage terminal proteins

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-15

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

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

    Science.gov (United States)

    Ross, Alexa; Ward, Samantha; Hyman, Paul

    2016-01-01

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

  2. MetaPhinder-Identifying Bacteriophage Sequences in Metagenomic Data Sets

    DEFF Research Database (Denmark)

    Jurtz, Vanessa Isabell; Villarroel, Julia; Lund, Ole

    2016-01-01

    and understand them. Here we present MetaPhinder, a method to identify assembled genomic fragments (i.e. contigs) of phage origin in metage-nomic 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...

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

    Science.gov (United States)

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

    2016-08-18

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

  4. Bacteriophages Limit the Existence Conditions for Conjugative Plasmids

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

    Ross, Alexa; Ward, Samantha; Hyman, Paul

    2016-01-01

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

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

    Science.gov (United States)

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

  7. Bacteriophages as indicators of faecal pollution and enteric virus removal

    Science.gov (United States)

    Bacteriophages are an attractive alternative to fecal indicator bacteria (FIB), particularly as surrogates of enteric virus fate and transport due to their closer morphological and biological properties compared to FIB. Based on a meta-analysis of published data, we summarize con...

  8. Complete Genome Sequence of Bacillus thuringiensis Bacteriophage Smudge.

    Science.gov (United States)

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

    2016-08-18

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

  9. Bio-Control of Salmonella Enteritidis in Foods Using Bacteriophages

    Directory of Open Access Journals (Sweden)

    Hongduo Bao

    2015-08-01

    Full Text Available Two lytic phages, vB_SenM-PA13076 (PA13076 and vB_SenM-PC2184 (PC2184, were isolated from chicken sewage and characterized with host strains Salmonella Enteritidis (SE ATCC13076 and CVCC2184, respectively. Transmission electron microscopy revealed that they belonged to the family Myoviridae. The lytic abilities of these two phages in liquid culture showed 104 multiplicity of infection (MOI was the best in inhibiting bacteria, with PC2184 exhibiting more activity than PA13076. The two phages exhibited broad host range within the genus Salmonella. Phage PA13076 and PC2184 had a lytic effect on 222 (71.4% and 298 (95.8% of the 311 epidemic Salmonella isolates, respectively. We tested the effectiveness of phage PA13076 and PC2184 as well as a cocktail combination of both in three different foods (chicken breast, pasteurized whole milk and Chinese cabbage contaminated with SE. Samples were spiked with 1 × 104 CFU individual SE or a mixture of strains (ATCC13076 and CVCC2184, then treated with 1 × 108 PFU individual phage or a two phage cocktail, and incubated at 4 °C or 25 °C for 5 h. In general, the inhibitory effect of phage and phage cocktail was better at 4 °C than that at 25 °C, whereas the opposite result was observed in Chinese cabbage, and phage cocktail was better than either single phage. A significant reduction in bacterial numbers (1.5–4 log CFU/sample, p < 0.05 was observed in all tested foods. The two phages on the three food samples were relatively stable, especially at 4 ºC, with the phages exhibiting the greatest stability in milk. Our research shows that our phages have potential effectiveness as a bio-control agent of Salmonella in foods.

  10. Bio-Control of Salmonella Enteritidis in Foods Using Bacteriophages

    Science.gov (United States)

    Bao, Hongduo; Zhang, Pengyu; Zhang, Hui; Zhou, Yan; Zhang, Lili; Wang, Ran

    2015-01-01

    Two lytic phages, vB_SenM-PA13076 (PA13076) and vB_SenM-PC2184 (PC2184), were isolated from chicken sewage and characterized with host strains Salmonella Enteritidis (SE) ATCC13076 and CVCC2184, respectively. Transmission electron microscopy revealed that they belonged to the family Myoviridae. The lytic abilities of these two phages in liquid culture showed 104 multiplicity of infection (MOI) was the best in inhibiting bacteria, with PC2184 exhibiting more activity than PA13076. The two phages exhibited broad host range within the genus Salmonella. Phage PA13076 and PC2184 had a lytic effect on 222 (71.4%) and 298 (95.8%) of the 311 epidemic Salmonella isolates, respectively. We tested the effectiveness of phage PA13076 and PC2184 as well as a cocktail combination of both in three different foods (chicken breast, pasteurized whole milk and Chinese cabbage) contaminated with SE. Samples were spiked with 1 × 104 CFU individual SE or a mixture of strains (ATCC13076 and CVCC2184), then treated with 1 × 108 PFU individual phage or a two phage cocktail, and incubated at 4 °C or 25 °C for 5 h. In general, the inhibitory effect of phage and phage cocktail was better at 4 °C than that at 25 °C, whereas the opposite result was observed in Chinese cabbage, and phage cocktail was better than either single phage. A significant reduction in bacterial numbers (1.5–4 log CFU/sample, p < 0.05) was observed in all tested foods. The two phages on the three food samples were relatively stable, especially at 4 °C, with the phages exhibiting the greatest stability in milk. Our research shows that our phages have potential effectiveness as a bio-control agent of Salmonella in foods. PMID:26305252

  11. Bio-Control of Salmonella Enteritidis in Foods Using Bacteriophages.

    Science.gov (United States)

    Bao, Hongduo; Zhang, Pengyu; Zhang, Hui; Zhou, Yan; Zhang, Lili; Wang, Ran

    2015-08-24

    Two lytic phages, vB_SenM-PA13076 (PA13076) and vB_SenM-PC2184 (PC2184), were isolated from chicken sewage and characterized with host strains Salmonella Enteritidis (SE) ATCC13076 and CVCC2184, respectively. Transmission electron microscopy revealed that they belonged to the family Myoviridae. The lytic abilities of these two phages in liquid culture showed 104 multiplicity of infection (MOI) was the best in inhibiting bacteria, with PC2184 exhibiting more activity than PA13076. The two phages exhibited broad host range within the genus Salmonella. Phage PA13076 and PC2184 had a lytic effect on 222 (71.4%) and 298 (95.8%) of the 311 epidemic Salmonella isolates, respectively. We tested the effectiveness of phage PA13076 and PC2184 as well as a cocktail combination of both in three different foods (chicken breast, pasteurized whole milk and Chinese cabbage) contaminated with SE. Samples were spiked with 1 × 10(4) CFU individual SE or a mixture of strains (ATCC13076 and CVCC2184), then treated with 1 × 10(8) PFU individual phage or a two phage cocktail, and incubated at 4 °C or 25 °C for 5 h. In general, the inhibitory effect of phage and phage cocktail was better at 4 °C than that at 25 °C, whereas the opposite result was observed in Chinese cabbage, and phage cocktail was better than either single phage. A significant reduction in bacterial numbers (1.5-4 log CFU/sample, p < 0.05) was observed in all tested foods. The two phages on the three food samples were relatively stable, especially at 4 ºC, with the phages exhibiting the greatest stability in milk. Our research shows that our phages have potential effectiveness as a bio-control agent of Salmonella in foods.

  12. Evaluation of Mutual Drug-Drug Interaction within Geneva Cocktail for Cytochrome P450 Phenotyping using Innovative Dried Blood Sampling Method.

    Science.gov (United States)

    Bosilkovska, Marija; Samer, Caroline; Déglon, Julien; Thomas, Aurélien; Walder, Bernhard; Desmeules, Jules; Daali, Youssef

    2016-09-01

    Cytochrome P450 (CYP) activity can be assessed using a 'cocktail' phenotyping approach. Recently, we have developed a cocktail (Geneva cocktail) which combines the use of low-dose probes with a low-invasiveness dried blood spots (DBS) sampling technique and a single analytical method for the phenotyping of six major CYP isoforms. We have previously demonstrated that modulation of CYP activity after pre-treatment with CYP inhibitors/inducer could be reliably predicted using Geneva cocktail. To further validate this cocktail, in this study, we have verified whether probe drugs contained in the latter cause mutual drug-drug interactions. In a randomized, four-way, Latin-square crossover study, 30 healthy volunteers received low-dose caffeine, flurbiprofen, omeprazole, dextromethorphan and midazolam (a previously validated combination with no mutual drug-drug interactions); fexofenadine alone; bupropion alone; or all seven drugs simultaneously (Geneva cocktail). Pharmacokinetic profiles of the probe drugs and their metabolites were determined in DBS samples using both conventional micropipette sampling and new microfluidic device allowing for self-sampling. The 90% confidence intervals for the geometric mean ratios of AUC metabolite/AUC probe for CYP probes administered alone or within Geneva cocktail fell within the 0.8-1.25 bioequivalence range indicating the absence of pharmacokinetic interaction. The same result was observed for the chosen phenotyping indices, that is metabolic ratios at 2 hr (CYP1A2, CYP3A) or 3 hr (CYP2B6, CYP2C9, CYP2C19, CYP2D6) post-cocktail administration. DBS sampling could successfully be performed using a new microfluidic device. In conclusion, Geneva cocktail combined with an innovative DBS sampling device can be used routinely as a test for simultaneous CYP phenotyping. © 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  13. ‘Get in Early’; Biofilm and Wax Moth (Galleria mellonella) Models Reveal New Insights into the Therapeutic Potential of Clostridium difficile Bacteriophages

    Science.gov (United States)

    Nale, Janet Y.; Chutia, Mahananda; Carr, Philippa; Hickenbotham, Peter T.; Clokie, Martha R. J.

    2016-01-01

    Clostridium difficile infection (CDI) is a global health threat associated with high rates of morbidity and mortality. Conventional antibiotic CDI therapy can result in treatment failure and recurrent infection. C. difficile produces biofilms which contribute to its virulence and impair antimicrobial activity. Some bacteriophages (phages) can penetrate biofilms and thus could be developed to either replace or supplement antibiotics. Here, we determined the impact of a previously optimized 4-phage cocktail on C. difficile ribotype 014/020 biofilms, and additionally as adjunct to vancomycin treatment in Galleria mellonella larva CDI model. The phages were applied before or after biofilm establishment in vitro, and the impact was analyzed according to turbidity, viability counts and topography as observed using scanning electron and confocal microscopy. The infectivity profiles and efficacies of orally administered phages and/or vancomycin were ascertained by monitoring colonization levels and larval survival rates. Phages prevented biofilm formation, and penetrated established biofilms. A single phage application reduced colonization causing extended longevity in the remedial treatment and prevented disease in the prophylaxis group. Multiple phage doses significantly improved the larval remedial regimen, and this treatment is comparable to vancomycin and the combined treatments. Taken together, our data suggest that the phages significantly reduce C. difficile biofilms, and prevent colonization in the G. mellonella model when used alone or in combination with vancomycin. The phages appear to be highly promising therapeutics in the targeted eradication of CDI and the use of these models has revealed that prophylactic use could be a propitious therapeutic option. PMID:27630633

  14. 'Get in Early'; Biofilm and Wax Moth (Galleria mellonella) Models Reveal New Insights into the Therapeutic Potential of Clostridium difficile Bacteriophages.

    Science.gov (United States)

    Nale, Janet Y; Chutia, Mahananda; Carr, Philippa; Hickenbotham, Peter T; Clokie, Martha R J

    2016-01-01

    Clostridium difficile infection (CDI) is a global health threat associated with high rates of morbidity and mortality. Conventional antibiotic CDI therapy can result in treatment failure and recurrent infection. C. difficile produces biofilms which contribute to its virulence and impair antimicrobial activity. Some bacteriophages (phages) can penetrate biofilms and thus could be developed to either replace or supplement antibiotics. Here, we determined the impact of a previously optimized 4-phage cocktail on C. difficile ribotype 014/020 biofilms, and additionally as adjunct to vancomycin treatment in Galleria mellonella larva CDI model. The phages were applied before or after biofilm establishment in vitro, and the impact was analyzed according to turbidity, viability counts and topography as observed using scanning electron and confocal microscopy. The infectivity profiles and efficacies of orally administered phages and/or vancomycin were ascertained by monitoring colonization levels and larval survival rates. Phages prevented biofilm formation, and penetrated established biofilms. A single phage application reduced colonization causing extended longevity in the remedial treatment and prevented disease in the prophylaxis group. Multiple phage doses significantly improved the larval remedial regimen, and this treatment is comparable to vancomycin and the combined treatments. Taken together, our data suggest that the phages significantly reduce C. difficile biofilms, and prevent colonization in the G. mellonella model when used alone or in combination with vancomycin. The phages appear to be highly promising therapeutics in the targeted eradication of CDI and the use of these models has revealed that prophylactic use could be a propitious therapeutic option.

  15. T4 bacteriophage conjugated magnetic particles for E. coli capturing: Influence of bacteriophage loading, temperature and tryptone.

    Science.gov (United States)

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

    2017-03-01

    This work demonstrates the use of bacteriophage conjugated magnetic particles (Fe3O4) for the rapid capturing and isolation of Escherichia coli. The investigation of T4 bacteriophage adsorption to silane functionalised Fe3O4 with amine (NH2), carboxylic (COOH) and methyl (CH3) surface functional groups reveals the domination of net electrostatic and hydrophobic interactions in governing bacteriophage adsorption. The bare Fe3O4 and Fe3O4-NH2 with high T4 loading captured 3-fold more E. coli (∼70% capturing efficiency) compared to the low loading T4 on Fe3O4-COOH, suggesting the significance of T4 loading in E. coli capturing efficiency. Importantly, it is further revealed that E. coli capture is highly dependent on the incubation temperature and the presence of tryptone in the media. Effective E. coli capturing only occurs at 37°C in tryptone-containing media with the absence of either conditions resulted in poor bacteria capture. The incubation temperature dictates the capturing ability of Fe3O4/T4, whereby T4 and E. coli need to establish an irreversible binding that occurred at 37°C. The presence of tryptophan-rich tryptone in the suspending media was also critical, as shown by a 3-fold increase in E. coli capture efficiency of Fe3O4/T4 in tryptone-containing media compared to that in tryptone-free media. This highlights for the first time that successful bacteria capturing requires not only an optimum tailoring of the particle's surface physicochemical properties for favourable bacteriophage loading, but also an in-depth understanding of how factors, such as temperature and solution chemistry influence the subsequent bacteriophage-bacteria interactions. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2011-03-01

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

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

    Science.gov (United States)

    Bikard, David; Marraffini, Luciano A

    2012-02-01

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

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

    Science.gov (United States)

    Goodridge, Lawrence (Inventor)

    2007-01-01

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

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

    Science.gov (United States)

    2011-09-28

    including the possible use of bacteriophages [5]. There are more and more publications on successful bacteriophage treatment of various experimental and...Discov Today 14: 536–540. 7. Deresinski S (2009) Bacteriophage therapy: exploiting smaller fleas . Clin Infect Dis 48: 1096–1101. 8. Kutter E, De Vos D...PCR. PLoS ONE 5(6): e11337. 28. Smith HW, Huggins MB (1983) Effectiveness of phages in treating experimental Escherichia coli diarrhoea in calves

  20. Characterization of Paenibacillus larvae bacteriophages and their genomic relationships to firmicute bacteriophages.

    Science.gov (United States)

    Merrill, Bryan D; Grose, Julianne H; Breakwell, Donald P; Burnett, Sandra H

    2014-08-30

    Paenibacillus larvae is a Firmicute bacterium that causes American Foulbrood, a lethal disease in honeybees and is a major source of global agricultural losses. Although P. larvae phages were isolated prior to 2013, no full genome sequences of P. larvae bacteriophages were published or analyzed. This report includes an in-depth analysis of the structure, genomes, and relatedness of P. larvae myoviruses Abouo, Davis, Emery, Jimmer1, Jimmer2, and siphovirus phiIBB_Pl23 to each other and to other known phages. P. larvae phages Abouo, Davies, Emery, Jimmer1, and Jimmer2 are myoviruses with ~50 kbp genomes. The six P. larvae phages form three distinct groups by dotplot analysis. An annotated linear genome map of these six phages displays important identifiable genes and demonstrates the relationship between phages. Sixty phage assembly or structural protein genes and 133 regulatory or other non-structural protein genes were identifiable among the six P. larvae phages. Jimmer1, Jimmer2, and Davies formed stable lysogens resistant to superinfection by genetically similar phages. The correlation between tape measure protein gene length and phage tail length allowed identification of co-isolated phages Emery and Abouo in electron micrographs. A Phamerator database was assembled with the P. larvae phage genomes and 107 genomes of Firmicute-infecting phages, including 71 Bacillus phages. Phamerator identified conserved domains in 1,501 of 6,181 phamilies (only 24.3%) encoded by genes in the database and revealed that P. larvae phage genomes shared at least one phamily with 72 of the 107 other phages. The phamily relationship of large terminase proteins was used to indicate putative DNA packaging strategies. Analyses from CoreGenes, Phamerator, and electron micrograph measurements indicated Jimmer1, Jimmer2, Abouo and Davies were related to phages phiC2, EJ-1, KC5a, and AQ113, which are small-genome myoviruses that infect Streptococcus, Lactobacillus, and Clostridium

  1. Analysis of the benefits of vitamin cocktails in treating Charcot-Marie-Tooth disease type 1A.

    Science.gov (United States)

    Kaya, Ferdinand; Belin, Sophie; Micallef, Joelle; Blin, Olivier; Fontés, Michel

    2008-08-01

    We recently proposed that the use of high doses of ascorbic acid (AA) could constitute the first potential treatment for Charcot-Marie-Tooth disease type 1A (CMT1A).4 We investigated the potential benefits of using cocktails of vitamins for CMT1A therapy. We used transient transfection of Schwann cells with a construction placing the expression of a reporter gene under the control of the Schwann cell-specific promoter of PMP22. Transfected cells were cultured with or without addition of ascorbic acid, vitamin A, vitamin E, or a cocktail of these vitamins. Adding vitamin A or E counteracts the effect of ascorbic acid in inhibiting PMP22 expression. We thus recommend that vitamins A and E should not be included in combination with AA in clinical trials.

  2. Safety analysis of a Russian phage cocktail: from metagenomic analysis to oral application in healthy human subjects.

    Science.gov (United States)

    McCallin, Shawna; Alam Sarker, Shafiqul; Barretto, Caroline; Sultana, Shamima; Berger, Bernard; Huq, Sayeda; Krause, Lutz; Bibiloni, Rodrigo; Schmitt, Bertrand; Reuteler, Gloria; Brüssow, Harald

    2013-09-01

    Phage therapy has a long tradition in Eastern Europe, where preparations are comprised of complex phage cocktails whose compositions have not been described. We investigated the composition of a phage cocktail from the Russian pharmaceutical company Microgen targeting Escherichia coli/Proteus infections. Electron microscopy identified six phage types, with numerically T7-like phages dominating over T4-like phages. A metagenomic approach using taxonomical classification, reference mapping and de novo assembly identified 18 distinct phage types, including 7 genera of Podoviridae, 2 established and 2 proposed genera of Myoviridae, and 2 genera of Siphoviridae. De novo assembly yielded 7 contigs greater than 30 kb, including a 147-kb Myovirus genome and a 42-kb genome of a potentially new phage. Bioinformatic analysis did not reveal undesired genes and a small human volunteer trial did not associate adverse effects with oral phage exposure.

  3. Role of quenching on alpha/beta separation in liquid scintillation counting for several high capacity cocktails

    Energy Technology Data Exchange (ETDEWEB)

    Pujol, L.; Sanchez-Cabeza, J.-A. [Universidad Autonoma de Barcelona (Spain). Facultad de Ciencias

    1997-04-01

    The optimization of alpha/beta separation in liquid scintillation using pulse shape analysis is convenient for the simultaneous determination of alpha and beta emitters in natural water and other samples. In this work, alpha/beta separation was studied for different scintillant/vial combinations and it was observed that both the optimum pulse shape discrimination level and the total interference value (that is, the summed relative interference between alpha and beta spectra) were dependent on the sample quenching and independent of the scintillant/vial combination. These results provide a simple method for modifying the counting configuration, such as a change in the cocktail, vial or sample characteristics, without the need to perform exhaustive parameter optimizations. Also, it was observed that, for our counting conditions, the combination of Ultima Gold AB scintillation cocktail with Zinsser low diffusion vials presented the lowest total interference, namely 0.94 {+-} 0.28%, which is insignificant for the counting of environmental samples. (Author).

  4. Emergence of Ebola Virus Escape Variants in Infected Nonhuman Primates Treated with the MB-003 Antibody Cocktail.

    Science.gov (United States)

    Kugelman, Jeffrey R; Kugelman-Tonos, Johanny; Ladner, Jason T; Pettit, James; Keeton, Carolyn M; Nagle, Elyse R; Garcia, Karla Y; Froude, Jeffrey W; Kuehne, Ana I; Kuhn, Jens H; Bavari, Sina; Zeitlin, Larry; Dye, John M; Olinger, Gene G; Sanchez-Lockhart, Mariano; Palacios, Gustavo F

    2015-09-29

    MB-003, a plant-derived monoclonal antibody cocktail used effectively in treatment of Ebola virus infection in non-human primates, was unable to protect two of six animals when initiated 1 or 2 days post-infection. We characterized a mechanism of viral escape in one of the animals, after observation of two clusters of genomic mutations that resulted in five nonsynonymous mutations in the monoclonal antibody target sites. These mutations were linked to a reduction in antibody binding and later confirmed to be present in a viral isolate that was not neutralized in vitro. Retrospective evaluation of a second independent study allowed the identification of a similar case. Four SNPs in previously identified positions were found in this second fatality, suggesting that genetic drift could be a potential cause for treatment failure. These findings highlight the importance selecting different target domains for each component of the cocktail to minimize the potential for viral escape.

  5. A NOVEL STRAIN OF Aspergillus niger PRODUCING A COCKTAIL OF HYDROLYTIC DEPOLYMERISING ENZYMES FOR THE PRODUCTION OF SECOND GENERATION BIOFUELS

    Directory of Open Access Journals (Sweden)

    Namita Bansal

    2011-02-01

    Full Text Available The screening and isolation of fungi producing a cocktail of hydrolytic enzymes was studied. Among the various isolates obtained from different soil samples, a strain NS-2 was selected. The phylogenetic analysis of this strain showed highest homology (99% with Aspergillus niger. It was capable of producing cellulolytic, hemicellulolytic, amylolytic, and pectinolytic enzymes in appreciable titers on wheat bran based liquid and solid state media. The mixture of enzymes produced by this organism could effectively hydrolyze various domestic waste residues, revealing conversion efficiencies of 89 to 92% and produced high reducing sugar yields of 0.48 to 0.66 g/g of dry residue. This enzyme cocktail could potentially find a significant application in the conversion of agricultural and other waste residues having cellulose, hemicellulose, starch, and pectin as carbohydrates to produce simpler sugars which can be fermented for the production of second generation biofuels.

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Boratyński Janusz

    2009-01-01

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

  9. THE VALIDITY OF MYCOBACTERIUM TUBERCULOSIS ANTIGENS COCKTAIL: ESAT-6, CFP-10 AND MPT64 IN SPUTUM AND CEREBROSPINAL FLUID FOR PULMONARY TUBERCULOSIS AND TUBERCULOUS MENINGITIS DIAGNOSIS

    OpenAIRE

    Dewi Kartika Turbawaty; Nenny Gustiani; Livia Noviani; Ida Parwati

    2015-01-01

    Objective: To determine the validity of tuberculosis (TB) antigen cocktail (ESAT-6, CFP-10 and MPT64) for pulmonary tuberculosis and TB meningitis diagnosis. Methods: This is a descriptive observational study design. The study was conducted at the Clinical Pathology Laboratory of Dr. Hasan Sadikin General Hospital during September 2012 until March 2013 for the pulmonary tuberculosis study and from January 2014 to May 2014 for the TB meningitis study. The TB antigen cocktail rapid imm...

  10. Analysis of a Multi-component Multi-stage Malaria Vaccine Candidate--Tackling the Cocktail Challenge.

    Directory of Open Access Journals (Sweden)

    Alexander Boes

    Full Text Available Combining key antigens from the different stages of the P. falciparum life cycle in the context of a multi-stage-specific cocktail offers a promising approach towards the development of a malaria vaccine ideally capable of preventing initial infection, the clinical manifestation as well as the transmission of the disease. To investigate the potential of such an approach we combined proteins and domains (11 in total from the pre-erythrocytic, blood and sexual stages of P. falciparum into a cocktail of four different components recombinantly produced in plants. After immunization of rabbits we determined the domain-specific antibody titers as well as component-specific antibody concentrations and correlated them with stage specific in vitro efficacy. Using purified rabbit immune IgG we observed strong inhibition in functional in vitro assays addressing the pre-erythrocytic (up to 80%, blood (up to 90% and sexual parasite stages (100%. Based on the component-specific antibody concentrations we calculated the IC50 values for the pre-erythrocytic stage (17-25 μg/ml, the blood stage (40-60 μg/ml and the sexual stage (1.75 μg/ml. While the results underline the feasibility of a multi-stage vaccine cocktail, the analysis of component-specific efficacy indicates significant differences in IC50 requirements for stage-specific antibody concentrations providing valuable insights into this complex scenario and will thereby improve future approaches towards malaria vaccine cocktail development regarding the selection of suitable antigens and the ratios of components, to fine tune overall and stage-specific efficacy.

  11. Analysis of a Multi-component Multi-stage Malaria Vaccine Candidate—Tackling the Cocktail Challenge

    Science.gov (United States)

    Voepel, Nadja; Edgue, Gueven; Beiss, Veronique; Kapelski, Stephanie; Fendel, Rolf; Scheuermayer, Matthias; Pradel, Gabriele; Bolscher, Judith M.; Behet, Marije C.; Dechering, Koen J.; Hermsen, Cornelus C.; Sauerwein, Robert W.; Schillberg, Stefan; Reimann, Andreas; Fischer, Rainer

    2015-01-01

    Combining key antigens from the different stages of the P. falciparum life cycle in the context of a multi-stage-specific cocktail offers a promising approach towards the development of a malaria vaccine ideally capable of preventing initial infection, the clinical manifestation as well as the transmission of the disease. To investigate the potential of such an approach we combined proteins and domains (11 in total) from the pre-erythrocytic, blood and sexual stages of P. falciparum into a cocktail of four different components recombinantly produced in plants. After immunization of rabbits we determined the domain-specific antibody titers as well as component-specific antibody concentrations and correlated them with stage specific in vitro efficacy. Using purified rabbit immune IgG we observed strong inhibition in functional in vitro assays addressing the pre-erythrocytic (up to 80%), blood (up to 90%) and sexual parasite stages (100%). Based on the component-specific antibody concentrations we calculated the IC50 values for the pre-erythrocytic stage (17–25 μg/ml), the blood stage (40–60 μg/ml) and the sexual stage (1.75 μg/ml). While the results underline the feasibility of a multi-stage vaccine cocktail, the analysis of component-specific efficacy indicates significant differences in IC50 requirements for stage-specific antibody concentrations providing valuable insights into this complex scenario and will thereby improve future approaches towards malaria vaccine cocktail development regarding the selection of suitable antigens and the ratios of components, to fine tune overall and stage-specific efficacy. PMID:26147206

  12. Analysis of a Multi-component Multi-stage Malaria Vaccine Candidate--Tackling the Cocktail Challenge.

    Science.gov (United States)

    Boes, Alexander; Spiegel, Holger; Voepel, Nadja; Edgue, Gueven; Beiss, Veronique; Kapelski, Stephanie; Fendel, Rolf; Scheuermayer, Matthias; Pradel, Gabriele; Bolscher, Judith M; Behet, Marije C; Dechering, Koen J; Hermsen, Cornelus C; Sauerwein, Robert W; Schillberg, Stefan; Reimann, Andreas; Fischer, Rainer

    2015-01-01

    Combining key antigens from the different stages of the P. falciparum life cycle in the context of a multi-stage-specific cocktail offers a promising approach towards the development of a malaria vaccine ideally capable of preventing initial infection, the clinical manifestation as well as the transmission of the disease. To investigate the potential of such an approach we combined proteins and domains (11 in total) from the pre-erythrocytic, blood and sexual stages of P. falciparum into a cocktail of four different components recombinantly produced in plants. After immunization of rabbits we determined the domain-specific antibody titers as well as component-specific antibody concentrations and correlated them with stage specific in vitro efficacy. Using purified rabbit immune IgG we observed strong inhibition in functional in vitro assays addressing the pre-erythrocytic (up to 80%), blood (up to 90%) and sexual parasite stages (100%). Based on the component-specific antibody concentrations we calculated the IC50 values for the pre-erythrocytic stage (17-25 μg/ml), the blood stage (40-60 μg/ml) and the sexual stage (1.75 μg/ml). While the results underline the feasibility of a multi-stage vaccine cocktail, the analysis of component-specific efficacy indicates significant differences in IC50 requirements for stage-specific antibody concentrations providing valuable insights into this complex scenario and will thereby improve future approaches towards malaria vaccine cocktail development regarding the selection of suitable antigens and the ratios of components, to fine tune overall and stage-specific efficacy.

  13. Frankincense derived heavy terpene cocktail boosting breast cancer cell (MDA-MB-231 death in vitro

    Directory of Open Access Journals (Sweden)

    Faruck Lukmanul Hakkim

    2015-10-01

    Conclusions: Extracting anti-cancer active principle cocktail by simple Soxhlet method is cost effective and less time consuming. Our in vitro anti-cancer data forms the rationale for us to test heavy terpene complex in breast cancer xenograft model in vivo. Furthermore, fractionation and developing frankincense heavy terpene based breast cancer drug is the major goal of our laboratory.

  14. Thermal conductivity of the cryoprotective cocktail DP6 in cryogenic temperatures, in the presence and absence of synthetic ice modulators.

    Science.gov (United States)

    Ehrlich, Lili E; Malen, Jonathan A; Rabin, Yoed

    2016-10-01

    The thermal conductivity of the cryoprotective agent (CPA) cocktail DP6 in combination with synthetic ice modulators (SIMs) is measured in this study, using a transient hot-wire method. DP6 is a mixture of 3 M dimethyl sulfoxide (DMSO) and 3 M propylene glycol, which received significant attention in the cryobiology community in recent years. Tested SIMs include 6% 1,3Cyclohexanediol, 6% 2,3Butanediol, and 12% PEG400 (percentage by volume). This study integrates the scanning cryomacroscope for visual verification of crystallization and vitrification events. It is demonstrated that the thermal conductivity of the vitrifying CPA cocktail decreases monotonically with the decreasing temperature down to -180 °C. By contrast, the thermal conductivity of the crystalline material increases with decreasing temperature in the same temperature range. Results of this study demonstrate that the thermal conductivity may vary by three fold between the amorphous and crystalline phases of DP6 below the glass transition temperature of DP6 (Tg = -119 °C). The selected SIMs demonstrate the ability to inhibit crystallization in DP6, even at subcritical cooling rates. An additional ice suppression capability is observed by the Euro-Collins as a vehicle solution, disproportionate to its volume ratio in the cocktail. The implication of the observed thermal conductivity differences between the amorphous and crystalline phases of the same cocktail on cryopreservation simulations is significant in some cases and must be taken into account in thermal analyses of cryopreservation protocols.

  15. Simultaneous Determination of Cytochrome P450 Oxidation Capacity in Humans: A Review on the Phenotyping Cocktail Approach.

    Science.gov (United States)

    de Andrés, Fernando; LLerena, Adrián

    Intra- and/or inter-individual variability in drug response is mainly a result of either subtherapeutic or supratherapeutic plasma levels of the active drugs and their metabolites, with this variability mainly being influenced by differences in the rate of drug metabolism. Indeed, drug metabolism is largely determined by genetic polymorphism in the CYP enzymes, which are responsible for approximately 85% of the drug metabolism process. However, this genetic heterogeneity can accurately predict actual drug metabolizing capacity (oxidation phenotype) for some individuals: poor metabolizers (PMs), who cannot produce the drug metabolizing enzymes, and 20% of ultra-rapid metabolizers. According to EMA recommendations, phenotyping procedures for drug interaction studies and clinical research are therefore required to obtain actual data on the main CYP enzymes. With this purpose, cocktail phenotyping approaches give information on the activity of different CYPs in just one experiment. In this review, the issues related to the phenotyping of the main CYP enzymes are reviewed, and the current in vivo phenotyping cocktails are analysed: the sampling procedures, probe drugs utilized, analytical techniques and main applications are also discussed. Based on this analysis, a fully validated cocktail approach to measure the metabolic activity of the main CYP enzymes and drug transporters is still required. This novel approach should fulfil certain conditions: a faster and simpler analytical methodology to obtain information on several CYPs in one experiment, minimal sample amounts, and minimal doses of optimal probe drugs.

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

    Science.gov (United States)

    Bronfenbrenner, J J; Korb, C

    1925-11-30

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

  17. Impact of a Microbial Cocktail Used as a Starter Culture on Cocoa Fermentation and Chocolate Flavor

    Directory of Open Access Journals (Sweden)

    Igor Magalhães da Veiga Moreira

    2017-05-01

    Full Text Available Chocolate production suffered a vast impact with the emergence of the “witches’ broom” disease in cocoa plants. To recover cocoa production, many disease-resistant hybrid plants have been developed. However, some different cocoa hybrids produce cocoa beans that generate chocolate with variable quality. Fermentation of cocoa beans is a microbiological process that can be applied for the production of chocolate flavor precursors, leading to overcoming the problem of variable chocolate quality. The aim of this work was to use a cocktail of microorganisms as a starter culture on the fermentation of the ripe cocoa pods from PH15 cocoa hybrid, and evaluate its influence on the microbial communities present on the fermentative process on the compounds involved during the fermentation, and to perform the chocolate sensorial characterization. According to the results obtained, different volatile compounds were identified in fermented beans and in the chocolate produced. Bitterness was the dominant taste found in non-inoculated chocolate, while chocolate made with inoculated beans showed bitter, sweet, and cocoa tastes. 2,3-Butanediol and 2,3-dimethylpyrazine were considered as volatile compounds making the difference on the flavor of both chocolates. Saccharomyces cerevisiae UFLA CCMA 0200, Lactobacillus plantarum CCMA 0238, and Acetobacter pasteurianus CCMA 0241 are proposed as starter cultures for cocoa fermentation.

  18. Impact of a Microbial Cocktail Used as a Starter Culture on Cocoa Fermentation and Chocolate Flavor.

    Science.gov (United States)

    Magalhães da Veiga Moreira, Igor; de Figueiredo Vilela, Leonardo; da Cruz Pedroso Miguel, Maria Gabriela; Santos, Cledir; Lima, Nelson; Freitas Schwan, Rosane

    2017-05-09

    Chocolate production suffered a vast impact with the emergence of the "witches' broom" disease in cocoa plants. To recover cocoa production, many disease-resistant hybrid plants have been developed. However, some different cocoa hybrids produce cocoa beans that generate chocolate with variable quality. Fermentation of cocoa beans is a microbiological process that can be applied for the production of chocolate flavor precursors, leading to overcoming the problem of variable chocolate quality. The aim of this work was to use a cocktail of microorganisms as a starter culture on the fermentation of the ripe cocoa pods from PH15 cocoa hybrid, and evaluate its influence on the microbial communities present on the fermentative process on the compounds involved during the fermentation, and to perform the chocolate sensorial characterization. According to the results obtained, different volatile compounds were identified in fermented beans and in the chocolate produced. Bitterness was the dominant taste found in non-inoculated chocolate, while chocolate made with inoculated beans showed bitter, sweet, and cocoa tastes. 2,3-Butanediol and 2,3-dimethylpyrazine were considered as volatile compounds making the difference on the flavor of both chocolates. Saccharomyces cerevisiae UFLA CCMA 0200, Lactobacillus plantarum CCMA 0238, and Acetobacter pasteurianus CCMA 0241 are proposed as starter cultures for cocoa fermentation.

  19. A cocktail party model of spatial release from masking by both noise and speech interferers.

    Science.gov (United States)

    Jones, Gary L; Litovsky, Ruth Y

    2011-09-01

    A mathematical formula for estimating spatial release from masking (SRM) in a cocktail party environment would be useful as a simpler alternative to computationally intensive algorithms and may enhance understanding of underlying mechanisms. The experiment presented herein was designed to provide a strong test of a model that divides SRM into contributions of asymmetry and angular separation [Bronkhorst (2000). Acustica 86, 117-128] and to examine whether that model can be extended to include speech maskers. Across masker types the contribution to SRM of angular separation of maskers from the target was found to grow at a diminishing rate as angular separation increased within the frontal hemifield, contrary to predictions of the model. Speech maskers differed from noise maskers in the overall magnitude of SRM and in the contribution of angular separation (both greater for speech). These results were used to develop a modified model that achieved good fits to data for noise maskers (ρ=0.93) and for speech maskers (ρ=0.94) while using the same functions to describe separation and asymmetry components of SRM for both masker types. These findings suggest that this approach can be used to accurately model SRM for speech maskers in addition to primarily "energetic" noise maskers.

  20. A cocktail party model of spatial release from masking by both noise and speech interferers a)

    Science.gov (United States)

    Jones, Gary L.; Litovsky, Ruth Y.

    2011-01-01

    A mathematical formula for estimating spatial release from masking (SRM) in a cocktail party environment would be useful as a simpler alternative to computationally intensive algorithms and may enhance understanding of underlying mechanisms. The experiment presented herein was designed to provide a strong test of a model that divides SRM into contributions of asymmetry and angular separation [Bronkhorst (2000). Acustica 86, 117–128] and to examine whether that model can be extended to include speech maskers. Across masker types the contribution to SRM of angular separation of maskers from the target was found to grow at a diminishing rate as angular separation increased within the frontal hemifield, contrary to predictions of the model. Speech maskers differed from noise maskers in the overall magnitude of SRM and in the contribution of angular separation (both greater for speech). These results were used to develop a modified model that achieved good fits to data for noise maskers (ρ = 0.93) and for speech maskers (ρ = 0.94) while using the same functions to describe separation and asymmetry components of SRM for both masker types. These findings suggest that this approach can be used to accurately model SRM for speech maskers in addition to primarily “energetic” noise maskers. PMID:21895087

  1. Mechanistic modeling of enzymatic hydrolysis of cellulose integrating substrate morphology and cocktail composition.

    Science.gov (United States)

    Huron, Maïté; Hudebine, Damien; Lopes Ferreira, Nicolas; Lachenal, Dominique

    2016-05-01

    A mechanistic model of enzymatic hydrolysis taking into account the morphology of the cellulosic particles and its evolution with time was developed. The individual behavior of the main enzymes involved in the reaction (cellobiohydrolases, endoglucanases, and β-glucosidases), as well as synergy effects, were also included. A large panel of experimental tests was done to fit and validate the model. This database included different enzymes mixtures and operating conditions and allowed to determine and compare with accuracy the adsorption and kinetic parameters of the different enzymes. Model predictions on short hydrolysis times were very satisfactory. On longer times, a deactivation constant was added to represent the hydrolysis slowdown. The model also allowed to predict the impact of enzymes ratios and initial substrate parameters (chain length distribution, polymerization degree) on hydrolysis, and to follow the evolution of these parameters with time. This model revealed general trends on the impact of cellulose morphology on hydrolysis. It is a useful tool to better understand the mechanisms involved in enzymatic hydrolysis of cellulose and to determine optimal cellulolytic cocktails for process design. © 2015 Wiley Periodicals, Inc.

  2. ACID EVAPORATION OF ULTIMA GOLD TM AB LIQUID SCINTILLATION COCKTAIL RESIDUE

    Energy Technology Data Exchange (ETDEWEB)

    Kyser, E.; Fondeur, F.; Crump, S.

    2011-12-21

    Prior analyses of samples from the F/H Lab solutions showed the presence of diisopropylnapthalene (DIN), a major component of Ultima Gold{trademark} AB liquid scintillation cocktail (LSC). These solutions are processed through H-Canyon Tank 10.5 and ultimately through the 17.8E evaporator. Similar solutions originated in SRNL streams sent to the same H Canyon tanks. This study examined whether the presence of these organics poses a process-significant hazard for the evaporator. Evaporation and calorimetry testing of surrogate samples containing 2000 ppm of Ultima Gold{trademark} AB LSC in 8 M nitric acid have been completed. These experiments showed that although reactions between nitric acid and the organic components do occur, they do not appear to pose a significant hazard for runaway reactions or generation of energetic compounds in canyon evaporators. The amount of off-gas generated was relatively modest and appeared to be well within the venting capacity of the H-Canyon evaporators. A significant fraction of the organic components likely survives the evaporation process primarily as non-volatile components that are not expected to represent any new process concerns during downstream operations such as neutralization. Laboratory Waste solutions containing minor amounts of DIN can be safely received, stored, transferred, and processed through the canyon waste evaporator.

  3. A Comparison of Blood Factor XII Autoactivation in Buffer, Protein Cocktail, Serum, and Plasma Solutions

    Science.gov (United States)

    Golas, Avantika; Yeh, Chyi-Huey Josh; Pitakjakpipop, Harit; Siedlecki, Christopher A.; Vogler, Erwin A.

    2012-01-01

    Activation of blood plasma coagulation in vitro by contact with material surfaces is demonstrably dependent on plasma-volume-to-activator-surface-area ratio. The only plausible explanation consistent with current understanding of coagulation-cascade biochemistry is that procoagulant stimulus arising from the activation complex of the intrinsic pathway is dependent on activator surface area. And yet, it is herein shown that activation of the blood zymogen factor XII (Hageman factor, FXII) dissolved in buffer, protein cocktail, heat-denatured serum, and FXI deficient plasma does not exhibit activator surface-area dependence. Instead, a highly-variable burst of procoagulant-enzyme yield is measured that exhibits no measurable kinetics, sensitivity to mixing, or solution-temperature dependence. Thus, FXII activation in both buffer and protein-containing solutions does not exhibit characteristics of a biochemical reaction but rather appears to be a “mechanochemical” reaction induced by FXII molecule interactions with hydrophilic activator particles that do not formally adsorb blood proteins from solution. Results of this study strongly suggest that activator surface-area dependence observed in contact activation of plasma coagulation does not solely arise at the FXII activation step of the intrinsic pathway. PMID:23117212

  4. The Effect of Vinpocetine on Human Cytochrome P450 Isoenzymes by Using a Cocktail Method

    Directory of Open Access Journals (Sweden)

    Lingti Kong

    2016-01-01

    Full Text Available Vinpocetine is a derivative of the alkaloid vincamine, which had been prescribed for chronic cerebral vascular ischemia and acute ischemic stroke or used as a dietary supplement for its several different mechanisms of biological activities. However, information on the cytochrome P450 (CYP enzyme-mediated drug metabolism has not been previously studied. The present study was performed to investigate the effects of vinpocetine on CYPs activity, and cocktail method was used, respectively. To evaluate the effects of vinpocetine on the activity of human CYP3A4, CYP2C9, CYP2C19, CYP2D6, and CYP2E1, human liver microsomes were utilized to incubate with the mixed CYPs probe substrates and the target components. The results indicate that vinpocetine exhibited weak inhibitory effect on the CYP2C9, where the IC50 value is 68.96 μM, whereas the IC50 values for CYP3A4, CYP2C19, CYP2D6, and CYP2E1 were all over range of 100 μM, which showed that vinpocetine had no apparent inhibitory effects on these CYPs. In conclusion, the results indicated that drugs metabolized by CYP2C9 coadministrated with vinpocetine may require attention or dose adjustment.

  5. Oral T4-like phage cocktail application to healthy adult volunteers from Bangladesh

    Energy Technology Data Exchange (ETDEWEB)

    Sarker, Shafiqul Alam, E-mail: sasarker@icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); McCallin, Shawna; Barretto, Caroline [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Berger, Bernard, E-mail: bernard.berger@rdls.nestle.com [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Pittet, Anne-Cecile [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Sultana, Shamima, E-mail: shamima@icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); Krause, Lutz, E-mail: ltz.krause@gmail.com [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Huq, Sayeda, E-mail: sayeeda@mail.icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); Bibiloni, Rodrigo, E-mail: Rodrigo.Bibiloni@agresearch.co.nz [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Bruttin, Anne, E-mail: anne.bruttin@rdls.nestle.com [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Reuteler, Gloria, E-mail: gloria.reuteler@rdls.nestle.com [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Bruessow, Harald, E-mail: harald.bruessow@rdls.nestle.com [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland)

    2012-12-20

    The genomic diversity of 99 T4-like coliphages was investigated by sequencing an equimolar mixture with Illumina technology and screening them against different databases for horizontal gene transfer and undesired genes. A 9-phage cocktail was given to 15 healthy adults from Bangladesh at a dose of 3 Multiplication-Sign 10{sup 9} and 3 Multiplication-Sign 10{sup 7} plaque-forming units and placebo respectively. Phages were detected in 64% of the stool samples when subjects were treated with higher titer phage, compared to 30% and 28% with lower-titer phage and placebo, respectively. No Escherichia coli was present in initial stool samples, and no amplification of phage was observed. One percent of the administered oral phage was recovered from the feces. No adverse events were observed by self-report, clinical examination, or from laboratory tests for liver, kidney, and hematology function. No impact of oral phage was seen on the fecal microbiota composition with respect to bacterial 16S rRNA from stool.

  6. Sequence and comparative analysis of Leuconostoc dairy bacteriophages.

    Science.gov (United States)

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

    2014-04-17

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

  7. Isolation and characterization of bacteriophage T4 base plates.

    Science.gov (United States)

    Poglazov, B F; Rodikova, L P; Sultanova, R A

    1972-10-01

    A method for isolating bacteriophage T4 base plates from lysates of Escherichia coli B cells infected with the ts mutant in gene 19, ts B31 has been developed. By electrophoresis in polyacrylamide gel with sodium dodecyl sulfate the base plates have been shown to contain five to seven protein components with molecular weights of 36,000, 53,000, 66,000, 81,000, 87,000, and probably about 100,000. Electron microscope studies have demonstrated that base plates may occur in two structural states: in the form of hexagons or stars. Star rays and short fibrils are not radial or elongated and are turned sideways at an angle to the radius. Base plates do not complement in vitro with free tail cores isolated after disintegration of particles of the wild-type bacteriophage.

  8. Bacteriophage exclusion, a new defense system

    Science.gov (United States)

    Barrangou, Rodolphe; van der Oost, John

    2015-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Haq Irshad

    2012-01-01

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

  11. Effect of HZE particles and space hadrons on bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

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

    1983-01-01

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

  12. Effect of HZE particles and space hadrons on bacteriophages

    Science.gov (United States)

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

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

  13. BACTERIOPHAGE ENDOLYSINS AND THEIR USE IN BIOTECHNOLOGICAL PROCESSES

    Directory of Open Access Journals (Sweden)

    Lenka Tišáková

    2014-02-01

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

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

    Science.gov (United States)

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

    2016-02-01

    Salmonella and Campylobacter are major causes of foodborne related illness and are traditionally associated with consuming undercooked poultry and/or consuming products that have been cross contaminated with raw poultry. Many of the isolated Salmonella and Campylobacter that can cause disease have displayed antimicrobial resistance phenotypes. Although poultry producers have reduced on-the-farm overuse of antimicrobials, antimicrobial resistant Salmonella and Campylobacter strains still persist. One method of bio-control, that is producing promising results, is the use of lytic bacteriophages. This review will highlight the current emergence and persistence of antimicrobial resistant Salmonella and Campylobacter recovered from poultry as well as bacteriophage research interventions and limitations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Polymorphism of DNA conformation inside the bacteriophage capsid.

    Science.gov (United States)

    Leforestier, Amélie

    2013-03-01

    Double-stranded DNA bacteriophage genomes are packaged into their icosahedral capsids at the highest densities known so far (about 50 % w:v). How the molecule is folded at such density and how its conformation changes upon ejection or packaging are fascinating questions still largely open. We review cryo-TEM analyses of DNA conformation inside partially filled capsids as a function of the physico-chemical environment (ions, osmotic pressure, temperature). We show that there exists a wide variety of DNA conformations. Strikingly, the different observed structures can be described by some of the different models proposed over the years for DNA organisation inside bacteriophage capsids: either spool-like structures with axial or concentric symmetries, or liquid crystalline structures characterised by a DNA homogeneous density. The relevance of these conformations for the understanding of DNA folding and unfolding upon ejection and packaging in vivo is discussed.

  16. Insights into bacteriophage application in controlling Vibrio species

    Directory of Open Access Journals (Sweden)

    Vengadesh Letchumanan

    2016-07-01

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

  17. Genetic effects of space hadrons on bacteriophage under Alpine conditions.

    Science.gov (United States)

    Yurov, S S; Belkin, V S; Leont'eva, G A; Knjaseva, I N; Mozgovoy, E G; Kuzin, A M; Akoev, I G

    1980-01-01

    A dried film culture of bacteriophage T4Br + was kept in a lead bioblock for 366 days under Alpine conditions at an altitude of 6100 m above sea level to study the genetic effect of space hadrons. In the gelatin-like film under study we discovered some film plots with markedly reduced bacteriophage survival. In such plots, the mutation frequency exceeded the spontaneous background mutation rate 60-100 times. The spectrum of r mutations as classified into standard groups rI, rII and rIII differed from that found for other model radiation systems such as gamma-ray radiation in buffer or nutrient broth, and hadron and HZE particle radiation under space flight conditions. Reversion analysis of 159 rII mutants showed that 54.4% had small and elongated deletions, 23.16% had point mutations, and 22.5% of all the mutants had both small deletion and point mutations.

  18. Effect of HZE particles and space hadrons on bacteriophages.

    Science.gov (United States)

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

    1983-01-01

    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 gamma 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.

  19. Degradation studies on Escherichia coli capsular polysaccharides by bacteriophages.

    Science.gov (United States)

    Nimmich, W

    1997-08-01

    The serologically and structurally related Eschrichia coli capsular polysaccharides (K antigens) K13, K20, and K23 were found to be depolymerized by the bacteriophages phi K13 and phi K20 to almost similar oligomer profiles as shown by polyacrylamide gel electrophoresis. The phage-polysaccharide interactions were followed by an increase of reducing 2-keto-3-deoxyoctulosonic acid due to a phage-associated glycanase that catalyzed the hydrolytic cleavage of common beta-ketopyranosidic 2-keto-3-deoxyoctulosonic acid linkages. The related E. coli K antigens K18, K22, and K100 as well as the Haemophilus influenzae type b capsular polysaccharide were degraded by bacteriophage phi K100 with different efficacy. It is suggested that phi K100 enzymatically cleaves ribitol-5-phosphate bonds as the only structural feature present in all the polysaccharides investigated.

  20. Insights into Bacteriophage Application in Controlling Vibrio Species

    Science.gov (United States)

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

    2016-01-01

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