Displaying publications 21 - 40 of 56 in total

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  1. Isolation and Characterization of Large Marine Bacteriophage (Myoviridae), VhKM4 Infecting Vibrio harveyi
    Lal TM, Sano M, Ransangan J
    J Aquat Anim Health, 2017 Mar;29(1):26-30.
    PMID: 28166465 DOI: 10.1080/08997659.2016.1249578
    The causative agent responsible for vibriosis in tropical fish aquaculture, Vibrio harveyi, has become a major bacterial pathogen. Studies suggest that this bacterium has developed resistance to antibiotics commonly used in aquaculture. In view of this situation and the requirement for the proposed postantibiotic era, bacteriophage therapy seems to be a promising control strategy for fish vibriosis. In this study, a lytic Vibrio phage VhKM4 belonging to a member of large, marine Myoviridae was successfully isolated. It exhibited bacteriolysis to both V. harveyi VHJR7 and V. parahaemolyticus ATCC 17802. The latent period of the VhKM4 phage was recorded at 60 min. It also recorded average burst size of approximately 52 plaque-forming units per infected cell. A strong bacteriolytic activity at low multiplicity of infection of 0.01 indicates the effectiveness of this large marine myovirid against fish pathogenic strain of V. harveyi VHJR7. Received June 16, 2016; accepted October 7, 2016.
    Matched MeSH terms: Bacteriophages
  2. Fulltext Bacteriophages and their applications
    Thung, T.Y., Lee, E., Tan, C.W., Malcolm, T.T.H., New, C.Y., Ramzi, O.S.B., et al.
    Food Research, 2018;2(5):404-414.
    MyJurnal
    Bacteriophages are ubiquitous in our world, mainly in the oceans, soil, the water and food
    we consume. They can be used efficiently in modern biotechnology, as well as alternatives
    to antibiotics for many antibiotic resistant bacterial strains. Phages can be used as vehicles
    for vaccines both DNA and protein, for the detection of pathogenic bacterial strain, as biocontrol
    agents in agriculture and food industry. This review outlines the properties as well
    as the influence of different external physical and chemical factors like temperature and
    acidity on phage persistence. A better understanding of the complex problem of phage
    sensitivity to external factors may be useful for other researchers working with phages.
    Furthermore, the applications of bacteriophages were described in this paper as well.
    Matched MeSH terms: Bacteriophages
  3. Crude protein extraction protocol for phage N15 protelomerase in vitro enzymatic assays
    Chen Q, Narayanan K
    Anal Biochem, 2011 Jul 1;414(1):169-71.
    PMID: 21396906 DOI: 10.1016/j.ab.2011.03.006
    The phage N15 protelomerase enzyme (TelN) is essential for the replication of its genome by resolution of its telRL domain, located within a telomerase occupancy site (tos), into hairpin telomeres. Isolation of TelN for in vitro processing of tos, however, is a highly complex process, requiring multiple purification steps. In this study a simplified protocol for crude total protein extraction is described that retains the tos-cleaving activity of TelN for at least 4 weeks, greatly simplifying in vitro testing of its activity. This protocol may be extended for functional analysis of other phage and bacterial proteins, particularly DNA-processing enzymes.
    Matched MeSH terms: Bacteriophages/enzymology*
  4. Phage displayed Bacillus thuringiensis Cry1Ba4 toxin is toxic to Plutella xylostella
    Nathan S, Aziz DH, Mahadi NM
    Curr Microbiol, 2006 Nov;53(5):412-5.
    PMID: 17036210
    We constructed recombinant phage particles displaying the Bacillus thuringiensis Cry1Ba4 active toxin using the pfUSE5 and pComb3X phagemid vectors. The recombinant phage particles were screened and evaluated for displayed biologically active Cry1Ba4 toxin against the target insect larvae. Concurrent expression of Cry1Ba4 protoxin was carried out using the pETBlue -2 plasmid expression vector in Escherichia coli Tuner (DE3)pLacI and the protoxin was successfully expressed at a size of 129 kDa. In the bioassay, 3.30 mg crude extract of Cry1Ba4 protoxin, 9.35 x 10(9) TU and 7.70 x 10(9) TU of induced recombinant phage particles carrying Cry1Ba4 active toxin displayed on pComb3X and pFUSE5, respectively, demonstrated mortality of greater than 85% against Plutella xylostella (third-instar) within 48 hours. Thus, we have successfully displayed the Cry1Ba4 activated toxin on the surface of a phage and demonstrated toxicity towards larvae.
    Matched MeSH terms: Bacteriophages/genetics
  5. Could bacteriophages isolated from the sewage be the solution to methicillin-resistant Staphylococcus aureus?
    Tan CS, Aqiludeen NA, Tan R, Gowbei A, Mijen AB, Santhana Raj L, et al.
    Med J Malaysia, 2020 03;75(2):110-116.
    PMID: 32281590
    INTRODUCTIONS: The emergence of multidrug-resistant bacteria such as Methicillin-Resistant Staphylococcus aureus (MRSA) complicates the treatment of the simplest infection. Although glycopeptides such as vancomycin still proves to be effective in treating MRSA infections, the emergence of vancomycin-resistant strains limits the long term use of this antibiotic. Bacteriophages are ubiquitous bacterial viruses which is capable of infecting and killing bacteria including its antibiotic-resistant strains. Bactericidal bacteriophages use mechanisms that is distinct from antibiotics and is not affected by the antibioticresistant phenotypes.

    OBJECTIVES: The study was undertaken to evaluate the possibility to isolate bacteriolytic bacteriophages against S.aureus from raw sewage water and examine their efficacy as antimicrobial agents in vitro.

    METHODS: Bacteriophages were isolated from the raw sewage using the agar overlay method. Isolated bacteriophages were plaque purified to obtain homogenous bacteriophage isolates. The host range of the bacteriophages was determined using the spot test assay against the 25 MRSA and 36 MSSA isolates obtained from the Sarawak General Hospital. Staphylococcus saprophyticus, Staphylococcus sciuri and Staphylococcus xylosus were included as non-SA controls. The identity of the bacteriophages was identified via Transmission Electron Microscopy and genomic size analysis. Their stability at different pH and temperature were elucidated.

    RESULTS: A total of 10 lytic bacteriophages infecting S.aureus were isolated and two of them namely ΦNUSA-1 and ΦNUSA-10 from the family of Myoviridae and Siphoviridae respectively exhibited exceptionally broad host range against >80% of MRSA and MSSA tested. Both bacteriophages were specific to S.aureus and stable at both physiologic pH and temperature.

    CONCLUSION: This study demonstrated the abundance of S.aureus specific bacteriophages in raw sewage. Their high virulence against both MSSA and MRSA is an excellent antimicrobial characteristic which can be exploited for bacteriophage therapy against MRSA.

    Matched MeSH terms: Bacteriophages/isolation & purification*
  6. Fulltext Effect of different cloning strategies in pET-28a on solubility and functionality of a staphylococcal phage endolysin
    Tham HY, Song AA, Yusoff K, Tan GH
    Biotechniques, 2020 09;69(3):161-170.
    PMID: 32787565 DOI: 10.2144/btn-2020-0034
    Endolysins have been studied intensively as an alternative to antibiotics. In this study, endolysin derived from a phage which infects methicillin-resistant Staphylococcus aureus (MRSA) was cloned and expressed in Escherichia coli pET28a. Initially, the endolysin was cloned using BamHI/XhoI, resulting in expression of a recombinant endolysin which was expressed in inclusion bodies. While solubilization was successful, the protein remained nonfunctional. Recloning the endolysin using NcoI/XhoI resulted in expression of soluble and functional proteins at 18°C. The endolysin was able to form halo zones on MRSA plates and showed a reduction in turbidity of MRSA growth. Therefore, cloning strategies should be chosen carefully even in an established expression system as they could greatly affect the functionality of the expressed protein.
    Matched MeSH terms: Bacteriophages/genetics*
  7. Effect of storage temperature on the stability of spray dried bacteriophage powders
    Leung SSY, Parumasivam T, Nguyen A, Gengenbach T, Carter EA, Carrigy NB, et al.
    Eur J Pharm Biopharm, 2018 Jun;127:213-222.
    PMID: 29486303 DOI: 10.1016/j.ejpb.2018.02.033
    This study aimed to assess the robustness of using a spray drying approach and formulation design in producing inhalable phage powders. Two types of Pseudomonas phages, PEV2 (Podovirus) and PEV40 (Myovirus) in two formulations containing different amounts of trehalose (70% and 60%) and leucine (30% and 40%) were studied. Most of the surface of the produced powders was found to be covered in crystalline leucine. The powders were stored at 4 °C and 20 °C under vacuum. The phage stability and in vitro aerosol performance of the phage powders were examined on the day of production and after 1, 3 and 12 months of storage. A minor titer loss during production was observed for both phages (0.2-0.8 log10 pfu/ml). The storage stability of the produced phage powders was found to be phage and formulation dependent. No further reduction in titer occurred for PEV2 powders stored at 4 °C across the study. The formulation containing 30% leucine maintained the viability of PEV2 at 20 °C, while the formulation containing 40% leucine gradually lost titer over time with a storage reduction of ∼0.9 log10 pfu/ml measured after 12 months. In comparison, the PEV40 phage powders generally had a ∼ 0.5 log10 pfu/ml loss upon storage regardless of temperature. When aerosolized, the total in vitro lung doses of PEV2 were of the order of 107 pfu, except the formulation containing 40% leucine stored at 20 °C which had a lower lung dose. The PEV40 powders also had lung doses of 106-107 pfu. The results demonstrate that spray dried Myoviridae and Podoviridae phage in a simple formulation of leucine and trehalose can be successfully stored for one year at 4 °C and 20 °C with vacuum packaging.
    Matched MeSH terms: Bacteriophages/chemistry*
  8. Fulltext Efficacy of a bacteriophage isolated from chickens as a therapeutic agent for colibacillosis in broiler chickens
    Lau GL, Sieo CC, Tan WS, Hair-Bejo M, Jalila A, Ho YW
    Poult Sci, 2010 Dec;89(12):2589-96.
    PMID: 21076096 DOI: 10.3382/ps.2010-00904
    The efficacy of bacteriophage EC1, a lytic bacteriophage, against Escherichia coli O78:K80, which causes colibacillosis in poultry, was determined in the present study. A total of 480 one-day-old birds were randomly assigned to 4 treatments groups, each with 4 pens of 30 birds. Birds from the control groups (groups I and II) received PBS (pH 7.4) or 10(10) pfu of bacteriophage EC1, respectively. Group III consisted of birds challenged with 10(8) cfu of E. coli O78:K80 and treated with 10(10) pfu of bacteriophage EC1 at 2 h postinfection, whereas birds from group IV were challenged with 10(8) cfu of E. coli O78:K80 only. All the materials were introduced into the birds by intratracheal inoculation. Based on the results of the present study, the infection was found to be less severe in the treated E. coli-challenged group. Mean total viable cell counts of E. coli identified on eosin methylene blue agar (designated EMB + E. coli) in the lungs were significantly lower in treated, E. coli-challenged birds than in untreated, E. coli-challenged birds on d 1 and 2 postinfection. The EMB + E. coli isolation frequency was also lower in treated birds; no E. coli was detectable in blood samples on any sampling day, and E. coli were isolated only in the liver, heart, and spleen of treated chickens at a ratio of 2/6, 1/6, and 3/6, respectively, at d 1 postinfection. The BW of birds from the E. coli-challenged group treated with bacteriophage EC1 were not significantly different from those of birds from both control groups but were 15.4% higher than those of the untreated, E. coli-challenged group on d 21 postinfection. The total mortality rate of birds during the 3-wk experimental period decreased from 83.3% in the untreated, E. coli-challenged birds (group IV) to 13.3% in birds treated with bacteriophage EC1 (group III). These results suggest that bacteriophage EC1 is effective in vivo and could be used to treat colibacillosis in chickens.
    Matched MeSH terms: Bacteriophages/genetics; Bacteriophages/isolation & purification*; Bacteriophages/pathogenicity
  9. Expression and purification of a recombinant scFv towards the exotoxin of the pathogen, Burkholderia pseudomallei
    Lim KP, Li H, Nathan S
    J Microbiol, 2004 Jun;42(2):126-32.
    PMID: 15357306
    A single chain variable fragment (scFv) specific towards B. pseudomallei exotoxin had previously been generated from an existing hybridoma cell line (6E6AF83B) and cloned into the phage display vector pComb3H. In this study, the scFv was subcloned into the pComb3X vector to facilitate the detection and purification of expressed antibodies. Detection was facilitated by the presence of a hemagglutinin (HA) tag, and purification was facilitated by the presence of a histidine tag. The culture was grown at 30 degrees C until log phase was achieved and then induced with 1 mM IPTG in the absence of any additional carbon source. Induction was continued at 30 degrees C for five h. The scFv was discerned by dual processes-direct enzyme-linked immunosorbent assays (ELISA), and Western blotting. When compared to E. coli strains ER2537 and HB2151, scFv expression was observed to be highest in the E. coli strain Top10F'. The expressed scFv protein was purified via nickel-mediated affinity chromatography and results indicated that two proteins a 52 kDa protein, and a 30 kDa protein were co-purified. These antibodies, when blotted against immobilized exotoxin, exhibited significant specificity towards the exotoxin, compared to other B. pseudomallei antigens. Thus, these antibodies should serve as suitable reagents for future affinity purification of the exotoxin.
    Matched MeSH terms: Bacteriophages/genetics; Bacteriophages/growth & development; Bacteriophages/metabolism
  10. Application of streptavidin mass spectrometric immunoassay tips for immunoaffinity based antibody phage display panning
    Chin CF, Ler LW, Choong YS, Ong EB, Ismail A, Tye GJ, et al.
    J Microbiol Methods, 2016 Jan;120:6-14.
    PMID: 26581498 DOI: 10.1016/j.mimet.2015.11.007
    Antibody phage display panning involves the enrichment of antibodies against specific targets by affinity. In recent years, several new methods for panning have been introduced to accommodate the growing application of antibody phage display. The present work is concerned with the application of streptavidin mass spectrometry immunoassay (MSIA™) Disposable Automation Research Tips (D.A.R.T's®) for antibody phage display. The system was initially designed to isolate antigens by affinity selection for mass spectrometry analysis. The streptavidin MSIA™ D.A.R.T's® system allows for easy attachment of biotinylated target antigens on the solid surface for presentation to the phage library. As proof-of-concept, a domain antibody library was passed through the tips attached with the Hemolysin E antigen. After binding and washing, the bound phages were eluted via standard acid dissociation and the phages were rescued for subsequent panning rounds. Polyclonal enrichment was observed for three rounds of panning with five monoclonal domain antibodies identified. The proposed method allows for a convenient, rapid and semi-automated alternative to conventional antibody panning strategies.
    Matched MeSH terms: Bacteriophages/genetics; Bacteriophages/isolation & purification; Bacteriophages/chemistry
  11. Fulltext Keeping the Wolves at Bay: Antitoxins of Prokaryotic Type II Toxin-Antitoxin Systems
    Chan WT, Espinosa M, Yeo CC
    Front Mol Biosci, 2016;3:9.
    PMID: 27047942 DOI: 10.3389/fmolb.2016.00009
    In their initial stages of discovery, prokaryotic toxin-antitoxin (TA) systems were confined to bacterial plasmids where they function to mediate the maintenance and stability of usually low- to medium-copy number plasmids through the post-segregational killing of any plasmid-free daughter cells that developed. Their eventual discovery as nearly ubiquitous and repetitive elements in bacterial chromosomes led to a wealth of knowledge and scientific debate as to their diversity and functionality in the prokaryotic lifestyle. Currently categorized into six different types designated types I-VI, type II TA systems are the best characterized. These generally comprised of two genes encoding a proteic toxin and its corresponding proteic antitoxin, respectively. Under normal growth conditions, the stable toxin is prevented from exerting its lethal effect through tight binding with the less stable antitoxin partner, forming a non-lethal TA protein complex. Besides binding with its cognate toxin, the antitoxin also plays a role in regulating the expression of the type II TA operon by binding to the operator site, thereby repressing transcription from the TA promoter. In most cases, full repression is observed in the presence of the TA complex as binding of the toxin enhances the DNA binding capability of the antitoxin. TA systems have been implicated in a gamut of prokaryotic cellular functions such as being mediators of programmed cell death as well as persistence or dormancy, biofilm formation, as defensive weapons against bacteriophage infections and as virulence factors in pathogenic bacteria. It is thus apparent that these antitoxins, as DNA-binding proteins, play an essential role in modulating the prokaryotic lifestyle whilst at the same time preventing the lethal action of the toxins under normal growth conditions, i.e., keeping the proverbial wolves at bay. In this review, we will cover the diversity and characteristics of various type II TA antitoxins. We shall also look into some interesting deviations from the canonical type II TA systems such as tripartite TA systems where the regulatory role is played by a third party protein and not the antitoxin, and a unique TA system encoding a single protein with both toxin as well as antitoxin domains.
    Matched MeSH terms: Bacteriophages
  12. Fulltext In silico Analysis Reveals Distribution of Quorum Sensing Genes and Consistent Presence of LuxR Solos in the Pandoraea Species
    Chua KO, See-Too WS, Ee R, Lim YL, Yin WF, Chan KG
    Front Microbiol, 2019;10:1758.
    PMID: 31447806 DOI: 10.3389/fmicb.2019.01758
    The most common quorum sensing (QS) system in Gram-negative bacteria consists of signaling molecules called N-acyl-homoserine lactones (AHLs), which are synthesized by an enzyme AHL synthase (LuxI) and detected by a transcriptional regulator (LuxR) that are usually located in close proximity. However, many recent studies have also evidenced the presence of LuxR solos that are LuxR-related proteins in Proteobacteria that are devoid of a cognate LuxI AHL synthase. Pandoraea species are opportunistic pathogens frequently isolated from sputum specimens of cystic fibrosis (CF) patients. We have previously shown that P. pnomenusa strains possess QS activity. In this study, we examined the presence of QS activity in all type strains of Pandoraea species and acquired their complete genome sequences for holistic bioinformatics analyses of QS-related genes. Only four out of nine type strains (P. pnomenusa, P. sputorum, P. oxalativorans, and P. vervacti) showed QS activity, and C8-HSL was the only AHL detected. A total of 10 canonical luxIs with adjacent luxRs were predicted by bioinformatics from the complete genomes of aforementioned species and publicly available Pandoraea genomes. No orphan luxI was identified in any of the genomes. However, genes for two LuxR solos (LuxR2 and LuxR3 solos) were identified in all Pandoraea genomes (except two draft genomes with one LuxR solo gene), and P. thiooxydans was the only species that harbored no QS-related activity and genes. Except the canonical LuxR genes, LuxIs and LuxR solos of Pandoraea species were distantly related to the other well-characterized QS genes based on phylogenetic clustering. LuxR2 and LuxR3 solos might represent two novel evolutionary branches of LuxR system as they were found exclusively only in the genus. As a few luxR solos were located in close proximity with prophage sequence regions in the genomes, we thus postulated that these luxR solos could be transmitted into genus Pandoraea by transduction process mediated by bacteriophage. The bioinformatics approach developed in this study forms the basis for further characterization of closely related species. Overall, our findings improve the current understanding of QS in Pandoraea species, which is a potential pharmacological target in battling Pandoraea infections in CF patients.
    Matched MeSH terms: Bacteriophages
  13. Fulltext Isolation and Characterization of Six Vibrio parahaemolyticus Lytic Bacteriophages From Seafood Samples
    Tan CW, Rukayadi Y, Hasan H, Abdul-Mutalib NA, Jambari NN, Hara H, et al.
    Front Microbiol, 2021;12:616548.
    PMID: 33776954 DOI: 10.3389/fmicb.2021.616548
    Vibrio parahaemolyticus is a foodborne pathogen that is frequently isolated from a variety of seafood. To control this pathogenic Vibrio spp., the implementation of bacteriophages in aquaculture and food industries have shown a promising alternative to antibiotics. In this study, six bacteriophages isolated from the seafood samples demonstrated a narrow host range specificity that infecting only the V. parahaemolyticus strains. Morphological analysis revealed that bacteriophages Vp33, Vp22, Vp21, and Vp02 belong to the Podoviridae family, while bacteriophages Vp08 and Vp11 were categorized into the Siphoviridae family. All bacteriophages were composed of DNA genome and showed distinctive restriction fragment length polymorphism. The optimal MOI for bacteriophage propagation was determined to be 0.001 to 1. One-step growth curve revealed that the latent period ranged from 10 to 20 min, and the burst size of bacteriophage was approximately 17 to 51 PFU/cell. The influence of temperature and pH levels on the stability of bacteriophages showed that all bacteriophages were optimally stable over a wide range of temperatures and pH levels. In vitro lytic activity of all bacteriophages demonstrated to have a significant effect against V. parahaemolyticus. Besides, the application of a bacteriophage cocktail instead of a single bacteriophage suspension was observed to have a better efficiency to control the growth of V. parahaemolyticus. Results from this study provided a basic understanding of the physiological and biological properties of the isolated bacteriophages before it can be readily used as a biocontrol agent against the growth of V. parahaemolyticus.
    Matched MeSH terms: Bacteriophages
  14. Community-acquired pneumonia: aetiology, antibiotic resistance and prospects of phage therapy
    Sheam MM, Syed SB, Nain Z, Tang SS, Paul DK, Ahmed KR, et al.
    J Chemother, 2020 Dec;32(8):395-410.
    PMID: 32820711 DOI: 10.1080/1120009X.2020.1807231
    Bacteria are the most common aetiological agents of community-acquired pneumonia (CAP) and use a variety of mechanisms to evade the host immune system. With the emerging antibiotic resistance, CAP-causing bacteria have now become resistant to most antibiotics. Consequently, significant morbimortality is attributed to CAP despite their varying rates depending on the clinical setting in which the patients being treated. Therefore, there is a pressing need for a safe and effective alternative or supplement to conventional antibiotics. Bacteriophages could be a ray of hope as they are specific in killing their host bacteria. Several bacteriophages had been identified that can efficiently parasitize bacteria related to CAP infection and have shown a promising protective effect. Thus, bacteriophages have shown immense possibilities against CAP inflicted by multidrug-resistant bacteria. This review provides an overview of common antibiotic-resistant CAP bacteria with a comprehensive summarization of the promising bacteriophage candidates for prospective phage therapy.
    Matched MeSH terms: Bacteriophages
  15. Genome Organization of Escherichia Phage YD-2008.s: A New Entry to Siphoviridae Family
    Sellvam D, Lau NS, Arip YM
    Trop Life Sci Res, 2018 Mar;29(1):37-50.
    PMID: 29644014 DOI: 10.21315/tlsr2018.29.1.3
    Malaysia is one of the countries that are loaded with mega biodiversity which includes microbial communities. Phages constitute the major component in the microbial communities and yet the numbers of discovered phages are just a minute fraction of its population in the biosphere. Taking into account of a huge numbers of waiting to be discovered phages, a new bacteriophage designated as Escherichia phage YD-2008.s was successfully isolated using Escherichia coli ATCC 11303 as the host. Phage YD-2008.s poses icosahedral head measured at 57nm in diameter with a long non-contractile flexible tail measured at 107nm; proving the phage as one of the members of Siphoviridae family under the order of Caudovirales. Genomic sequence analyses revealed phage YD-2008.s genome as linear dsDNA of 44,613 base pairs with 54.6% G+C content. Sixty-two open reading frames (ORFs) were identified on phage YD-2008.s full genome, using bioinformatics annotation software; Rapid Annotation using Subsystem Technology (RAST). Among the ORFs, twenty-eight of them code for functional proteins. Thirty two are classified as hypothetical proteins and there are two unidentified proteins. Even though majority of the coded putative proteins have high amino acids similarities to phages from the genus Hk578likevirus of the Siphoviridae family, yet phage YD-2008.s stands with its' own distinctiveness. Therefore, this is another new finding to Siphoviridae family as well as to the growing list of viruses in International Committee on Taxonomy of Viruses (ICTV) database.
    Matched MeSH terms: Bacteriophages
  16. Fulltext Genome organization of Eschrichia phage YD-2008.s: a new entry to siphoviridae family
    Sellvam, Dharmela, Yahya Mat Arip, Nyok, Sean Lau
    Trop Life Sci Res, 2018;29(1):37-50.
    MyJurnal
    Malaysia is one of the countries that are loaded with mega biodiversity which
    includes microbial communities. Phages constitute the major component in the microbial
    communities and yet the numbers of discovered phages are just a minute fraction of
    its population in the biosphere. Taking into account of a huge numbers of waiting to be
    discovered phages, a new bacteriophage designated as Escherichia phage YD-2008.s
    was successfully isolated using Escherichia coli ATCC 11303 as the host. Phage YD-2008.s poses icosahedral head measured at 57nm in diameter with a long non-contractile
    flexible tail measured at 107nm; proving the phage as one of the members of Siphoviridae
    family under the order of Caudovirales. Genomic sequence analyses revealed phage
    YD-2008.s genome as linear dsDNA of 44,613 base pairs with 54.6% G+C content.
    Sixty-two open reading frames (ORFs) were identified on phage YD-2008.s full genome,
    using bioinformatics annotation software; Rapid Annotation using Subsystem Technology
    (RAST). Among the ORFs, twenty-eight of them code for functional proteins. Thirty two are
    classified as hypothetical proteins and there are two unidentified proteins. Even though
    majority of the coded putative proteins have high amino acids similarities to phages from the
    genus Hk578likevirus of the Siphoviridae family, yet phage YD-2008.s stands with its’ own
    distinctiveness. Therefore, this is another new finding to Siphoviridae family as well as to the
    growing list of viruses in International Committee on Taxonomy of Viruses (ICTV) database.
    Matched MeSH terms: Bacteriophages
  17. Evaluation of the efficacy of chitosan nanoparticles loaded ΦKAZ14 bacteriophage in the biological control of colibacillosis in chickens
    Kaikabo AA, AbdulKarim SM, Abas F
    Poult Sci, 2017 Feb 01;96(2):295-302.
    PMID: 27702916 DOI: 10.3382/ps/pew255
    Disease inflicted by avian pathogenic Escherichia coli (APEC) causes economic losses and burden to the poultry industry worldwide. In this study, the efficacy of chitosan nanoparticles loaded ΦKAZ14 (C-ΦKAZ14 NPs) as an oral biological therapy for Colibacillosis was evaluated. C-ΦKAZ14 NPs containing 10(7) PFU/ml of ΦKAZ14 (Myoviridae; T4-like coliphage) bacteriophage were used to treat experimentally APEC-infected COBB 500 broiler chicks. C-ΦKAZ14 NPs and ΦKAZ14 bacteriophage were administered orally in a single dose. The clinical symptoms, mortality, and pathology in the infected birds were recorded and compared with those of control birds that did not receive C-ΦKAZ14 NPs or naked ΦKAZ14 bacteriophage. The results showed that C-ΦKAZ14 NP intervention decreased mortality from 58.33 to 16.7% with an increase in the protection rate from 42.00 to 83.33%. The bacterial colonization of the intestines of infected birds was significantly higher in the untreated control than in the C-ΦKAZ14 NP-treated group (2.30×10(9) ± 0.02 and 0.79×10(3) ± 0.10 CFU/mL, respectively) (P ≤ 0.05). Similarly, a significant difference in the fecal shedding of Escherichia coli was observed on d 7 post challenge between the untreated control and the C-ΦKAZ14 NP-treated group (2.35×10(9) ± 0.05 and 1.58×10(3) ± 0.06 CFU/mL, respectively) (P ≤ 0.05). Similar trends were observed from d 14 until d 21 when the experiment was terminated. Treatment with C-ΦKAZ14 NPs improved the body weights of the infected chicks. A difference in body weight on d 7 post challenge was observed between the untreated control and the C-ΦKAZ14 NP-treated group (140 ± 20 g and 160 ± 20 g, respectively). The increase was significant (P ≤ 0.05) on d 21 between the 2 groups (240 ± 30 g and 600 ± 80 g, respectively). Consequently, the clinical signs and symptoms were ameliorated upon treatment with C-ΦKAZ14 NPs compared with infected untreated birds. In all, based on the results, it can be concluded that the encapsulation of bacteriophage could enhance bacteriophage therapy and is a valuable approach for controlling APEC infections in poultry.
    Matched MeSH terms: Bacteriophages
  18. A phage-displayed cyclic peptide that interacts tightly with the immunodominant region of hepatitis B surface antigen
    Tan WS, Tan GH, Yusoff K, Seow HF
    J Clin Virol, 2005 Sep;34(1):35-41.
    PMID: 16087122
    The surface antigen (HBsAg) of hepatitis B virus (HBV) is highly conformational and generally evokes protective humoral immune response in human. A disulfide constrained random heptapeptide library displayed on the coat protein III of filamentous bacteriophage M13 was employed to select specific ligands that interact with HBsAg subtype ad. Fusion phages carrying the amino acid sequence ETGAKPH and other related sequences were isolated. The binding site of peptide ETGAKPH was located on the immunodominant region of HBsAg. An equilibrium binding assay in solution showed that the phage binds tightly to HBsAg with a relative dissociation constant (KDrel) of 2.9+/-0.9 nM. The phage bearing this peptide has the potential to be used as a diagnostic reagent and two assays for detecting HBsAg in blood samples are described.
    Matched MeSH terms: Bacteriophages/genetics
  19. A defect in DNA topoisomerase II activity in ataxia-telangiectasia cells
    Mohamed R, Pal Singh S, Kumar S, Lavin MF
    Biochem Biophys Res Commun, 1987 Nov 30;149(1):233-8.
    PMID: 2825700
    DNA topoisomerase type I and II activities were determined by serial dilution in nuclear extracts from control and ataxia-telangiectasia lymphoblastoid cells. Topoisomerase I activity, assayed by relaxation of supercoiled plasmid DNA, was found to be approximately the same in both cell types. In order to remove interference from topoisomerase I, the activity of topoisomerase II was measured by the unknotting of knotted P4 phage DNA in the presence of ATP. The activity of topoisomerase II was markedly reduced in two ataxia-telangiectasia cell lines, AT2ABR and AT8ABR, compared to controls. This reduction in activity was detected with increasing concentration of protein and in time course experiments at a single protein concentration. A third cell line, AT3ABR, did not have a detectably lower activity of topoisomerase II when assayed under these conditions. The difference in topoisomerase II activity in the ataxia-telangiectasia cell lines examined may reflect to some extent the heterogeneity observed in this syndrome.
    Matched MeSH terms: Bacteriophages/genetics
  20. A Self-Replicating Linear DNA
    Liew PS, Tan TH, Wong YC, Sim EUH, Lee CW, Narayanan K
    ACS Synth Biol, 2020 04 17;9(4):804-813.
    PMID: 32196315 DOI: 10.1021/acssynbio.9b00478
    TelN and tos are a unique DNA linearization unit isolated from bacteriophage N15. While being transferable, the TelN cleaving-rejoining activities remained stable to function on tos in both bacterial and mammalian environments. However, TelN contribution in linear plasmid replication in mammalian cells remains unknown. Herein, we investigated the association of TelN in linear tos-containing DNA (tos-DNA) replication in mammalian cells. Additionally, the mammalian origin of replication (ori) that is well-known to initiate the replication event of plasmid vectors was also studied. In doing so, we identified that both TelN and mammalian initiation sites were essential for the replication of linear tos-DNA, determined by using methylation sensitive DpnI/MboI digestion and polymerase chain reaction (PCR) amplification approaches. Furthermore, we engineered the linear tos-DNA to be able to retain in mammalian cells using S/MAR technology. The resulting S/MAR containing tos-DNA was robust for at least 15 days, with (1) continuous tos-DNA replication, (2) correct splicing of gene transcripts, and (3) stable exogenous gene expression that was statistically comparable to the endogenous gene expression level. Understanding the activities of TelN and tos in mammalian cells can potentially provide insights for adapting this simple DNA linearization unit in developing novel genetic engineering tools, especially to the eukaryotic telomere/telomerase study.
    Matched MeSH terms: Bacteriophages/genetics
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