Articoli di riviste: "Bacteriophages Genetics"

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Auslander, Noam, Ayal B. Gussow, Sean Benler, Yuri I. Wolf e Eugene V. Koonin. "Seeker: alignment-free identification of bacteriophage genomes by deep learning". Nucleic Acids Research 48, n. 21 (12 ottobre 2020): e121-e121. http://dx.doi.org/10.1093/nar/gkaa856.

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Abstract Recent advances in metagenomic sequencing have enabled discovery of diverse, distinct microbes and viruses. Bacteriophages, the most abundant biological entity on Earth, evolve rapidly, and therefore, detection of unknown bacteriophages in sequence datasets is a challenge. Most of the existing detection methods rely on sequence similarity to known bacteriophage sequences, impeding the identification and characterization of distinct, highly divergent bacteriophage families. Here we present Seeker, a deep-learning tool for alignment-free identification of phage sequences. Seeker allows rapid detection of phages in sequence datasets and differentiation of phage sequences from bacterial ones, even when those phages exhibit little sequence similarity to established phage families. We comprehensively validate Seeker's ability to identify previously unidentified phages, and employ this method to detect unknown phages, some of which are highly divergent from the known phage families. We provide a web portal (seeker.pythonanywhere.com) and a user-friendly Python package (github.com/gussow/seeker) allowing researchers to easily apply Seeker in metagenomic studies, for the detection of diverse unknown bacteriophages.

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Timmons, Michael S., M. Lieb e Richard C. Deonier. "RECOMBINATION BETWEEN IS5 ELEMENTS: REQUIREMENT FOR HOMOLOGY AND RECOMBINATION FUNCTIONS". Genetics 113, n. 4 (1 agosto 1986): 797–810. http://dx.doi.org/10.1093/genetics/113.4.797.

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ABSTRACT Intermolecular recombination between two IS5 elements was measured, using bacteriophage lambda recombination vectors, and was compared to recombination between two copies of an SV40 segment cloned into the same vectors. Experiments were conducted in the presence and in the absence of RecA and Red functions, and with the recombining inserts in the same or in reversed orientation. Under all conditions, IS5 elements recombined in a manner similar to the SV40 inserts, indicating that IS-encoded functions did not confer measurable additional intermolecular recombination ability to IS5 in E. coli K-12. Bacteriophages containing reversed IS5 inserts, for which the 16 base pair (bp) termini are identical in 15 positions and which display 12 bp of uninterrupted homology, recombined at approximately the same low frequency under Rec+ and Rec- conditions, indicating that these short homologies were not good substrates for the Rec system. Bacteriophages having reversed inserts recombined better under Red+ than under Red- conditions, but the crossovers were located in nonhomologous regions flanking the element termini. This suggests that 12-bp homologies are not good substrates for the Red system.

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Węgrzyn, Grzegorz. "Should Bacteriophages Be Classified as Parasites or Predators?" Polish Journal of Microbiology 71, n. 1 (23 febbraio 2022): 3–9. http://dx.doi.org/10.33073/pjm-2022-005.

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Abstract Bacteriophages are viruses infecting bacteria and propagating in bacterial cells. They were discovered over 100 years ago, and for decades they played crucial roles as models in genetics and molecular biology and as tools in genetic engineering and biotechnology. Now we also recognize their huge role in natural environment and their importance in human health and disease. Despite our understanding of bacteriophage mechanisms of development, these viruses are described as parasites or predators in the literature. From the biological point of view, there are fundamental differences between parasites and predators. Therefore, in this article, I asked whether bacteriophages should be classified as former or latter biological entities. Analysis of the literature and biological definitions led me to conclude that bacteriophages are parasites rather than predators and should be classified and described as such. If even more precise ecological classification is needed, bacteriophages can perhaps be included in the group of parasitoids. It might be the most appropriate formal classification of these viruses, especially if strictly virulent phages are considered, contrary to phages which lysogenize host cells and those which develop according to the permanent infection mode (or chronic cycle, like filamentous phages) revealing features of classical parasites.

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Schrader, Holly S., John O. Schrader, Jeremy J. Walker, Thomas A. Wolf, Kenneth W. Nickerson e Tyler A. Kokjohn. "Bacteriophage infection and multiplication occur inPseudomonas aeruginosastarved for 5 years". Canadian Journal of Microbiology 43, n. 12 (1 dicembre 1997): 1157–63. http://dx.doi.org/10.1139/m97-164.

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Bacteriophages specific for Pseudomonas aeruginosa and Escherichia coli were examined for their ability to multiply in stationary phase hosts. Four out of five bacteriophages tested, including E. coli bacteriophage T7M, were able to multiply in stationary phase hosts. The bacteriophage ACQ had a mean burst size of approximately 1000 in exponential phase P. aeruginosa hosts and 102 in starved hosts, with corresponding latent periods that increased from 65 to 210 min. The bacteriophage UT1 had a mean burst size of approximately 211 in exponential phase P. aeruginosa hosts and 11 in starved hosts, with latent periods that increased from a mean of 90 min in exponential phase hosts to 165 min in starved hosts. Bacteriophage multiplication occurred whether or not the hosts had entered stationary phase, either because the cultures had been incubated for 24 h or were starved. Significantly, bacteriophage multiplication occurred in P. aeruginosa, which had been starved for periods of 24 h, several weeks, or 5 years. Only one P. aeruginosa virus, BLB, was found to be incapable of multiplication in stationary phase hosts. These results reveal that starvation does not offer bacterial hosts refuge from bacteriophage infection and suggest that bacteriophages will be responsible for significant bacterial mortality in most natural ecosystems.Key words: bacteriophage multiplication, stationary phase, starvation.

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Klein, Gracjana, e Costa Georgopoulos. "Identification of Important Amino Acid Residues That Modulate Binding of Escherichia coli GroEL to Its Various Cochaperones". Genetics 158, n. 2 (1 giugno 2001): 507–17. http://dx.doi.org/10.1093/genetics/158.2.507.

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Abstract Genetic experiments have shown that the GroEL/GroES chaperone machine of Escherichia coli is absolutely essential, not only for bacterial growth but also for the propagation of many bacteriophages including λ. The virulent bacteriophages T4 and RB49 are independent of the host GroES function, because they encode their own cochaperone proteins, Gp31 and CocO, respectively. E. coli groEL44 mutant bacteria do not form colonies above 42° nor do they propagate bacteriophages λ, T4, or RB49. We found that the vast majority (40/46) of spontaneous groEL44 temperature-resistant colonies at 43° were due to the presence of an intragenic suppressor mutation. These suppressors define 21 different amino acid substitutions in GroEL, each affecting one of 13 different amino acid residues. All of these amino acid residues are located at or near the hinge, which regulates the large en bloc movements of the GroEL apical domain. All of these intragenic suppressors support bacteriophages λ, T4, and RB49 growth to various extents in the presence of the groEL44 allele. Since it is known that the GroEL44 mutant protein does not interact effectively with Gp31, the suppressor mutations should enhance cochaperone binding. Analogous intragenic suppressor studies were conducted with the groEL673 temperature-sensitive allele.

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Brüggemann, Holger, e Rolf Lood. "Bacteriophages InfectingPropionibacterium acnes". BioMed Research International 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/705741.

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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 thePropionibacterium acnesbacteriophage research and point out how bacteriophage research has been an important part of the research onP. acnesitself. 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 useP. acnesbacteriophages as a therapeutic strategy to combatP. acnes-associated diseases will be discussed.

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Benedi, Vicente J., Miguel Regué, Sebastián Albertí, Silvia Camprubí e Juan M. Tomás. "Influence of environmental conditions on infection of Klebsiella pneumoniae by two different types of bacteriophages". Canadian Journal of Microbiology 37, n. 4 (1 aprile 1991): 270–75. http://dx.doi.org/10.1139/m91-042.

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The adsorption and efficiency of plating of bacteriophages FC3-1 and FC3-9 on Klebsiella pneumoniae C3 (serotype O1:K66) cells grown at different pHs and temperatures were quantitated. Bacteriophage FC3-1, with lipopolysaccharide as its bacterial receptor, showed a large decrease in efficiency of plating on bacteria grown at low pH or low temperature. Under the same conditions, no significant decrease in efficiency of plating was found for bacteriophage FC3-9, a phage requiring capsule and lipopolysaccharide for its adsorption and carrying capsule-depolymerizing activity. We demonstrate that K. pneumoniae C3 cells grown at low pH or low temperature have less lipopolysaccharide exposed on their surface. We conclude that this is why lipopolysaccharide-specific phage FC3-1 less efficiently infects bacterial cells grown under those conditions. We propose that bacteriophage FC3-9 efficiently infects bacterial cells grown at low pH or low temperature because its enzymatic activity on the capsule makes lipopolysaccharide available to this phage. Key words: Klebsiella pneumoniae, bacteriophages, isolation, environmental conditions.

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Verbeken, Gilbert, Isabelle Huys, Jean-Paul Pirnay, Serge Jennes, Nina Chanishvili, Jacques Scheres, Andrzej Górski, Daniel De Vos e Carl Ceulemans. "Taking Bacteriophage Therapy Seriously: A Moral Argument". BioMed Research International 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/621316.

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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.

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Gong, Chao, Spencer Heringa, Randhir Singh, Jinkyung Kim e Xiuping Jiang. "Isolation and characterization of bacteriophages specific to hydrogen-sulfide-producing bacteria". Canadian Journal of Microbiology 59, n. 1 (gennaio 2013): 39–45. http://dx.doi.org/10.1139/cjm-2012-0245.

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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.

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Jończyk-Matysiak, Ewa, Marlena Kłak, Beata Weber-Dąbrowska, Jan Borysowski e Andrzej Górski. "Possible Use of Bacteriophages Active againstBacillus anthracisand OtherB. cereusGroup Members in the Face of a Bioterrorism Threat". BioMed Research International 2014 (2014): 1–14. http://dx.doi.org/10.1155/2014/735413.

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Anthrax is an infectious fatal disease with epidemic potential. Nowadays, bioterrorism usingBacillus anthracisis a real possibility, and thus society needs an effective weapon to neutralize this threat. The pathogen may be easily transmitted to human populations. It is easy to store, transport, and disseminate and may survive for many decades. Recent data strongly support the effectiveness of bacteriophage in treating bacterial diseases. Moreover, it is clear that bacteriophages should be considered a potential incapacitative agent against bioterrorism using bacteria belonging toB. cereusgroup, especiallyB. anthracis. Therefore, we have reviewed the possibility of using bacteriophages active againstBacillus anthracisand other species of theB. cereusgroup in the face of a bioterrorism threat.

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Crane, Adele, Joy Abaidoo, Gabriella Beltran, Danielle Fry, Colleen Furey, Noe Green, Ravneet Johal et al. "The Complete Genome Sequence of the Staphylococcus Bacteriophage Metroid". G3 Genes|Genomes|Genetics 10, n. 9 (1 settembre 2020): 2975–79. http://dx.doi.org/10.1534/g3.120.401365.

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Abstract Phages infecting bacteria of the genus Staphylococcus play an important role in their host’s ecology and evolution. On one hand, horizontal gene transfer from phage can encourage the rapid adaptation of pathogenic Staphylococcus enabling them to escape host immunity or access novel environments. On the other hand, lytic phages are promising agents for the treatment of bacterial infections, especially those resistant to antibiotics. As part of an ongoing effort to gain novel insights into bacteriophage diversity, we characterized the complete genome of the Staphylococcus bacteriophage Metroid, a cluster C phage with a genome size of 151kb, encompassing 254 predicted protein-coding genes as well as 4 tRNAs. A comparative genomic analysis highlights strong similarities – including a conservation of the lysis cassette – with other Staphylococcus cluster C bacteriophages, several of which were previously characterized for therapeutic applications.

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Guidolin, A., e P. A. Manning. "Genetics of Vibrio cholerae and its bacteriophages." Microbiological Reviews 51, n. 2 (1987): 285–98. http://dx.doi.org/10.1128/mmbr.51.2.285-298.1987.

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Guidolin, A., e P. A. Manning. "Genetics of Vibrio cholerae and its bacteriophages." Microbiological Reviews 51, n. 2 (1987): 285–98. http://dx.doi.org/10.1128/mr.51.2.285-298.1987.

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Girones, Rosina, Juan T. Jofre e Albert Bosch. "Isolation of marine bacteria with antiviral properties". Canadian Journal of Microbiology 35, n. 11 (1 novembre 1989): 1015–21. http://dx.doi.org/10.1139/m89-169.

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We report in this study the isolation of marine bacteria with antiviral properties that have been tentatively classified as Moraxella. These bacteria retained their virucidal capacity after prolonged subcultivation in the laboratory. The virus-inactivating agent could not be separated from the viable marine bacteria, indicating that the active agent(s) either remains associated to the microorganisms or has a very short lifetime, or both. The antiviral capacity of the isolated microorganisms was highly specific for poliovirus. No virucidal effect was observed against other strains of enteroviruses, such as Coxsackie and ECHO virus, rotavirus SA11, or bacteriophages proposed as indicators of the virological quality of water, such as coliphage f2 and bacteriophage B40-8, which infects Bacteroides fragilis.Key words: enterovirus, rotavirus, coliphages, bacteriophages, seawater, marine bacteria, antiviral activity, virus survival.

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Rigvava, Sophio, Irina Tchgkonia, Darejan Jgenti, Teona Dvalidze, James Carpino e Marina Goderdzishvili. "Comparative analysis of the biological and physical properties of Enterococcus faecalis bacteriophage vB_EfaS_GEC-EfS_3 and Streptococcus mitis bacteriophage vB_SmM_GEC-SmitisM_2". Canadian Journal of Microbiology 59, n. 1 (gennaio 2013): 18–21. http://dx.doi.org/10.1139/cjm-2012-0385.

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Enterococcus faecalis and Streptococcus mitis are common commensal inhabitants of the human gastrointestinal and genitourinary tracts. However, both species can be opportunistic pathogens and cause disease in nosocomial settings. These infections can be difficult to treat because of the frequency of antibiotic resistance among these strains. Bacteriophages are often suggested as an alternative therapeutic agent against these infections. In this study, E. faecalis and S. mitis strains were isolated from female patients with urinary tract infections. Bacteriophages active against these strains were isolated from sewage water from the Mtkvari River. Two phages, designated vB_EfaS_GEC-EfS_3 (Syphoviridae) and vB_SmM_GEC-SmitisM_2 (Myoviridae), were specific for E. faecalis and S. mitis, respectively. Each phage's growth patterns and adsorption rates were quantified. Sensitivity to ultraviolet light and temperature was determined, as was host range and serology. The S. mitis bacteriophage was found to be more resistant to ultraviolet light and exposure to high temperatures than the E. faecalis bacteriophage, despite having a much greater rate of replication. While each phage was able to infect a broad range of strains of the same species as the host species from which they were isolated, they were unable to infect other host species tested.

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Śliwa-Dominiak, Joanna, Ewa Suszyńska, Małgorzata Pawlikowska e Wiesław Deptuła. "Chlamydia bacteriophages". Archives of Microbiology 195, n. 10-11 (1 agosto 2013): 765–71. http://dx.doi.org/10.1007/s00203-013-0912-8.

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BÃ¯Â¿Â½rsheim, Knut Yngve. "Native marine bacteriophages". FEMS Microbiology Letters 102, n. 3-4 (aprile 1993): 141–59. http://dx.doi.org/10.1111/j.1574-6968.1993.tb05805.x.

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Smith, Leslie A., e John W. Drake. "Aspects of the Ultraviolet Photobiology of Some T-Even Bacteriophages". Genetics 148, n. 4 (1 aprile 1998): 1611–18. http://dx.doi.org/10.1093/genetics/148.4.1611.

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Abstract Bacteriophage T4 DNA metabolism is largely insulated from that of its host, although some host functions assist in the repair of T4 DNA damage. Environmental factors sometimes affect survival and mutagenesis after ultraviolet (UV) irradiation of T4, and can affect mutagenesis in many organisms. We therefore tested the effect of certain environmental factors and host genetic defects upon spontaneous and UV-induced mutagenesis and survival in T4 and some related T-even phages. Plating at pH 9 enhances UV resistance in T4 by about 14% compared to pH 7. The host cAMP regulatory system affects host survival after UV irradiation but does not affect T4 survival. Thermal rescue, the increasing survival of irradiated T4 with increasing plating temperature, occurs also in phage T6, but only weakly in phages T2 and RB69; this temperature effect is not altered by supplementing infected cells with additional Holliday resolvase (gp49) early in infection. Phage RB69 turns out to have almost 50% greater UV resistance than T4, but has a genome of about the same size; RB69 is UV-mutable but does not produce r mutants, which are easily seen in T2, T4, and T6. Spontaneous mutagenesis in T4 shows no dependence on medium and little dependence on temperature overall, but mutation rates can increase and probably decrease with temperature at specific sites. UV mutagenesis is not affected by incubating irradiated particles under various conditions before plating, in contrast to phage S13.

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Arsuaga, J., e Y. Diao. "DNA Knotting in Spooling Like Conformations in Bacteriophages". Computational and Mathematical Methods in Medicine 9, n. 3-4 (2008): 303–16. http://dx.doi.org/10.1080/17486700802167801.

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A number of idealized models have been proposed to explain the long range organization of the DNA in bacteriophages. However, none of these models can account for the distributions of complex knots found when examining DNA extracted from bacteriophage P4 capsids. Furthermore, these models do not consider possible chirality biases in the arrangement of the DNA molecule inside the capsid. In this paper, we address these two issues by proposing a randomized version of one of the most popular models: the coaxially spooled model. We present analytical and numerical results for the properties of the random polygons (knots) generated using this model. We show that such model can easily generate complex knotted conformations and although it accounts for some chirality of the organization of the DNA molecules inside bacteriophage capsids does not fully explain the experimental data.

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Armon, Robert, Max Arella e Pierre Payment. "A highly efficient second-step concentration technique for bacteriophages and enteric viruses using ammonium sulfate and Tween 80". Canadian Journal of Microbiology 34, n. 5 (1 maggio 1988): 651–55. http://dx.doi.org/10.1139/m88-107.

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Addition of Tween 80 to a 1.5% solution of beef extract was found to enhance the elution of bacteriophages adsorbed to electronegative filters. When reconcentration of the eluate was attempted by ammonium sulfate precipitation, a floating layer containing most of the viruses was formed. This floating layer can be obtained with several nonionic detergents including Tween 80 and under a salt saturation of 55% with ammonium sulfate, potassium tartrate, and sodium phosphate. Virus recovery ranged from 91 to 103% and was obtained with several bacteriophage strains. With poliovirus type 1, coxsackievirus B-4, and rotavirus SA-11 the recoveries were 100, 20, and 80%, respectively, but toxicity to cell culture was encountered: after removal of the detergent by a second floating layer method the recovery was 32% for poliovirus. Compared with organic flocculation, this method also had both improved recovery for bacteriophages and protective properties for samples frozen at −70 °C.

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Isaev, Artem, Alena Drobiazko, Nicolas Sierro, Julia Gordeeva, Ido Yosef, Udi Qimron, Nikolai V. Ivanov e Konstantin Severinov. "Phage T7 DNA mimic protein Ocr is a potent inhibitor of BREX defence". Nucleic Acids Research 48, n. 10 (27 aprile 2020): 5397–406. http://dx.doi.org/10.1093/nar/gkaa290.

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Abstract BREX (for BacteRiophage EXclusion) is a superfamily of common bacterial and archaeal defence systems active against diverse bacteriophages. While the mechanism of BREX defence is currently unknown, self versus non-self differentiation requires methylation of specific asymmetric sites in host DNA by BrxX (PglX) methyltransferase. Here, we report that T7 bacteriophage Ocr, a DNA mimic protein that protects the phage from the defensive action of type I restriction–modification systems, is also active against BREX. In contrast to the wild–type phage, which is resistant to BREX defence, T7 lacking Ocr is strongly inhibited by BREX, and its ability to overcome the defence could be complemented by Ocr provided in trans. We further show that Ocr physically associates with BrxX methyltransferase. Although BREX+ cells overproducing Ocr have partially methylated BREX sites, their viability is unaffected. The result suggests that, similar to its action against type I R–M systems, Ocr associates with as yet unidentified BREX system complexes containing BrxX and neutralizes their ability to both methylate and exclude incoming phage DNA.

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Dabrowski, Tomasz, e Bartlomiej Kwiatkowski. "Sensitivity of Vi phages III to gamma-radiation in the presence of cisplatin." Acta Biochimica Polonica 52, n. 2 (31 maggio 2005): 545–50. http://dx.doi.org/10.18388/abp.2005_3471.

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In this study we determined Vi bacteriophage III sensitivity to native cisplatin, gamma radiation ((60)Co) or to irradiated cisplatin, and checked the possibility of enhanced Vi bacteriophage III inactivation under combined exposure to cisplatin and gamma radiation. We used highly purified phage suspensions in 0.9% NaCl solution or phosphate-buffered saline. Phage suspensions were titrated using a double agar layer method. Our study implies that survival of Vi bacteriophage III shows an exponential inverse correlation with cisplatin concentration in the incubation medium and the time of phage incubation in the presence of cisplatin. The use of irradiated cisplatin reduces phage survival in comparison with suspensions containing non-irradiated cisplatin. Irradiation of phage suspension with cisplatin causes a significant increase of phage inactivation in comparison with either treatment alone. Our results suggest that presence of cisplatin in irradiated medium enhances the radiobiological effect on Vi bacteriophages III.

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Arendt, E. K., M. van de Guchte, A. G. Coffey, C. Daly e G. F. Fitzgerald. "Molecular genetics of bacteriophages of lactic acid bacteria". Le Lait 73, n. 2 (1993): 191–98. http://dx.doi.org/10.1051/lait:1993217.

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Rokyta, Darin R., Zaid Abdo e Holly A. Wichman. "The Genetics of Adaptation for Eight Microvirid Bacteriophages". Journal of Molecular Evolution 69, n. 3 (20 agosto 2009): 229–39. http://dx.doi.org/10.1007/s00239-009-9267-9.

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Sackman, Andrew M., e Darin R. Rokyta. "No Cost of Complexity in Bacteriophages Adapting to a Complex Environment". Genetics 212, n. 1 (26 febbraio 2019): 267–76. http://dx.doi.org/10.1534/genetics.119.302029.

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Benini, Stefano, Maria Chechik, Miguel Ortiz Lombardía, Sigrun Polier, Andrew Leech, Mikhail B. Shevtsov e Juan C. Alonso. "The 1.58 Å resolution structure of the DNA-binding domain of bacteriophage SF6 small terminase provides new hints on DNA binding". Acta Crystallographica Section F Structural Biology and Crystallization Communications 69, n. 4 (28 marzo 2013): 376–81. http://dx.doi.org/10.1107/s1744309113004399.

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Abstract (sommario):

DNA packaging in tailed bacteriophages and in evolutionarily related herpesviruses is controlled by a viral-encoded terminase. As in a number of other phages, in theBacillus subtilisbacteriophages SF6 and SPP1 the terminase complex consists of two proteins: G1P and G2P. The crystal structure of the N-terminal DNA-binding domain of the bacteriophage SF6 small terminase subunit G1P is reported. Structural comparison with other DNA-binding proteins allows a general model for the interaction of G1P with the packaging-initiation site to be proposed.

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Farfán, Juan, John M. Gonzalez e Martha Vives. "The immunomodulatory potential of phage therapy to treat acne: a review on bacterial lysis and immunomodulation". PeerJ 10 (25 luglio 2022): e13553. http://dx.doi.org/10.7717/peerj.13553.

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Background Characterized by an inflammatory pathogenesis, acne is the most common skin disorder worldwide. Altered sebum production, abnormal proliferation of keratinocytes, and microbiota dysbiosis represented by disbalance in Cutibacterium acnes population structure, have a synergic effect on inflammation of acne-compromised skin. Although the role of C. acnes as a single factor in acne development is still under debate, it is known that skin and skin-resident immune cells recognize this bacterium and produce inflammatory markers as a result. Control of the inflammatory response is frequently the target for acne treatment, using diverse chemical or physical agents including antibiotics. However, some of these treatments have side effects that compromise patient adherence and drug safety and in the case of antibiotics, it has been reported C. acnes resistance to these molecules. Phage therapy is an alternative to treat antibiotic-resistant bacterial strains and have been recently proposed as an immunomodulatory therapy. Here, we explore this perspective about phage therapy for acne, considering the potential immunomodulatory role of phages. Methodology Literature review was performed using four different databases (Europe PubMed Central-ePMC, Google Scholar, PubMed, and ScienceDirect). Articles were ordered and selected according to their year of publication, number of citations, and quartile of the publishing journal. Results The use of lytic bacteriophages to control bacterial infections has proven its promising results, and anti-inflammatory effects have been found for some bacteriophages and phage therapy. These effects can be related to bacterial elimination or direct interaction with immune cells that result in the regulation of pro-inflammatory cytokines. Studies on C. acnes bacteriophages have investigated their lytic activity, genomic structure, and stability on different matrices. However, studies exploring the potential of immunomodulation of these bacteriophages are still scarce. Conclusions C. acnes bacteriophages, as well as other phages, may have direct immunomodulatory effects that are yet to be fully elucidated. To our knowledge, to the date that this review was written, there are only two studies that investigate anti-inflammatory properties for C. acnes bacteriophages. In those studies, it has been evidenced reduction of pro-inflammatory response to C. acnes inoculation in mice after bacteriophage application. Nevertheless, these studies were conducted in mice, and the interaction with the immune response was not described. Phage therapy to treat acne can be a suitable therapeutic alternative to C. acnes control, which in turn can aid to restore the skin’s balance of microbiota. By controlling C. acnes colonization, C. acnes bacteriophages can reduce inflammatory reactions triggered by this bacterium.

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Efimov, Alexander, Eugene Kulikov, Alla Golomidova, Ilya Belalov, Vladislav Babenko e Andrey Letarov. "Isolation and sequencing of three RB49-like bacteriophages infecting O antigen-producing E. coli strains". F1000Research 10 (3 novembre 2021): 1113. http://dx.doi.org/10.12688/f1000research.74169.1.

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E. coli strains 4s, F5 and F17, whose O antigens are structurally characterized and shown to effectively shield the cell surface from bacteriophage attack, were used as the hosts to isolate novel RB49-like bacteriophages. Three novel phage isolates were obtained, and their genomes were sequenced and annotated. Despite high overall identity levels of these genomic sequences, the variants of large distal tail fiber subunit, orthologous to the bacteriophage T2 long tail receptor recognition protein gp38, were unique for each phage, suggesting their role in host range determination. The annotated genomes are available via NCBI Genbank, acc. numbers MZ504876-MZ504878.

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Zhukova, O. V., E. I. Kasikhina, M. N. Ostretsova e A. A. M. Nemer. "Bacteriophages in the treatment and prevention of atopic dermatitis and dermatoses complicated by secondary bacterial infection". Meditsinskiy sovet = Medical Council, n. 13 (9 agosto 2022): 66–72. http://dx.doi.org/10.21518/2079-701x-2022-16-13-66-72.

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Bacteriophages are a large group of viruses that can selectively affect bacteria. Bacteriophages and their ability to regulate the growth and activity of pathogenic microorganisms were discovered by scientists at the beginning of the 20th century. Further studies of the properties of bacteriophages led to the construction of the modern concept of virus activity and formed the ground of molecular genetics and biology. To date, more than 6 000 phage species are known to be ubiquitous, but a prerequisite for their existence is the presence of a bacterial host cell, proteins and energy resources serve as the basis for further viral replication. The ability of bacteriophages to selectively destroy bacterial host cells is of particular importance for the therapy and prevention of dermatoses with a potential risk of bacterial infection or pathogenetically aggravated by the activity of the bacterial flora. Such dermatoses include atopic dermatitis, acne, eczema, psoriasis, pyoderma. The article highlights the main advantages and features of bacteriophages, presents data from some of the currently available studies on the use of phages in dermatovenereology. To illustrate the possibility of using bacteriophages in dermatology, a clinical case of successful relief of exacerbation of IgE- independent atopic dermatitis with a high risk of secondary infection in an 8-year-old child is presented. In this case, as an additional to the recommended standard external anti-inflammatory therapy, a gel for external use was prescribed based on a complex of more than 70 virulent bacteriophages capable of inhibiting the growth of actual bacterial strains, among them Staphylococcus spp. (including S. aureus), Streptococcus spp. (including S. pyogenes), Cutibacterium acnes, etc. The range of bacteriophages in dermatovenereology can be expanded due to the constant growth of antibiotic resistance. The use of bacteriophages in routine dermatological practice requires further clinical trials.

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Cheleuitte-Nieves, Christopher, Ryan D. Heselpoth, Lars F. Westblade, Neil S. Lipman e Vincent A. Fischetti. "Searching for a Bacteriophage Lysin to Treat Corynebacterium bovis in Immunocompromised Mice". Comparative Medicine 70, n. 4 (1 agosto 2020): 328–35. http://dx.doi.org/10.30802/aalas-cm-19-000096.

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Corynebacterium bovis is the causative agent of Corynebacterium-associated hyperkeratosis in immunocompromised mice. The resulting skin pathology can be profound and can be associated with severe wasting, making the animals unsuitable for research. Although the administration of antibiotics is effective in resolving clinical symptoms, antibiotics do not eradicate the offending bacterium. Furthermore, antibiotic use may be contraindicated as it can affect tumor growth and is associated with Clostridioides difficile enterotoxemia in highly immunocompromised murine strains. Lysins, which are lytic enzymes obtained from bacteriophages, are novel antimicrobial agents for treating bacterial diseases. The advantage of lysins are its target specificity, with minimal off-target complications that could affect the host or the biology of the engrafted tumor. The aim of this study was to identify lysins active against C. bovis. Chemical activation of latent prophages by using mitomycin C in 3 C. bovis isolates did not cause bacteriophage induction as determined through plaque assays and transmission electron microscopy. As an alternative approach, 8 lysins associated with other bacterial species, including those from the closely related species C. falsenii, were tested for their lytic action against C. bovis but were unsuccessful. These findings were congruent with the previously reported genomic analysis of 21 C. bovis isolates, which failed to reveal bacteriophage sequences by using the PHAST and PHASTER web server tools. From these results, we suggest C. bovis is among those rare bacterial species devoid of lysogenic bacteriophages, thus making the identification of C. bovis-specific lysins more challenging. However, C. bovis may be a useful model organism for studying the effects of antiphage systems.

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31

Vasse, Marie, e Sébastien Wielgoss. "Bacteriophages of Myxococcus xanthus, a Social Bacterium". Viruses 10, n. 7 (18 luglio 2018): 374. http://dx.doi.org/10.3390/v10070374.

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Bacteriophages have been used as molecular tools in fundamental biology investigations for decades. Beyond this, however, they play a crucial role in the eco-evolutionary dynamics of bacterial communities through their demographic impact and the source of genetic information they represent. The increasing interest in describing ecological and evolutionary aspects of bacteria–phage interactions has led to major insights into their fundamental characteristics, including arms race dynamics and acquired bacterial immunity. Here, we review knowledge on the phages of the myxobacteria with a major focus on phages infecting Myxococcus xanthus, a bacterial model system widely used to study developmental biology and social evolution. In particular, we focus upon the isolation of myxophages from natural sources and describe the morphology and life cycle parameters, as well as the molecular genetics and genomics of the major groups of myxophages. Finally, we propose several interesting research directions which focus on the interplay between myxobacterial host sociality and bacteria–phage interactions.

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32

Yan, Jianlong, Xiangyu Fan e Jianping Xie. "Emerging Biomedicines Based on Bacteriophages". Critical Reviews in Eukaryotic Gene Expression 23, n. 4 (2013): 299–308. http://dx.doi.org/10.1615/critreveukaryotgeneexpr.2013006578.

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33

Wulff, Daniel L., e Michael E. Mahoney. "Cross-Specificities Between cII-like Proteins and pRE-like Promoters of Lambdoid Bacteriophages". Genetics 115, n. 4 (1 aprile 1987): 597–604. http://dx.doi.org/10.1093/genetics/115.4.597.

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ABSTRACT We have investigated the activation of transcription from the pRE promoters of phages λ, 21 and P22 by the λ and 21 cII proteins and the P22 c1 (cII-like) protein, using an in vivo system in which cII protein from a derepressed prophage activates transcription from a pRE DNA fragment on a multicopy plasmid. We find that each protein is highly specific for its own cognate pRE promoter, although measureable cross-reactions are observed. The primary recognition sequence for cII protein on λ pRE is a pair of TTGC repeat sequences in the sequence 5′-TTGCN6TTGC-3′ at the -35 region of the promoter. This same sequence is found in 21 pRE, while P22 pRE has the sequence 5′-TTGCN6TTGT-3′, which is the same as that of λctr1, a pRE + variant of λ. λctr1 pRE is half as active as λ+ pRE when assayed with either the λ cII or the P22 c1 proteins. Therefore, the single base change in the P22 repeat sequence cannot explain why the P22 c1 protein is much more active with P22 pRE than λ pRE. The dya5 mutation, a G→A change at position -43 of pRE, makes pRE a stronger promoter when assayed with either the λ or 21 cII proteins or the P22 c1 protein. We conclude that efficient activation of a cII-dependent promoter by a cII protein requires sequence information in addition to the TTGC repeat sequences. We do not know the characteristics of the proteins which are responsible for the specificity of each protein for its own cognate promoter. However, λdya8, which has a Glu27→Lys alteration in the λ cII protein and a cII + phenotype, results in a mutant cII protein that is much more highly specific than wild-type cII protein for its own cognate λ pRE promoter. This is especially remarkable because the dya8 amino acid alteration makes the helix-2 region (the region of the protein predicted to make contact with the phosphodiester backbone of the DNA) of λ cII protein conform exactly with the helix-2 region of the P22 c1 protein in both charge and charge distribution.

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34

Wood, Jonathan P. A., Stephanie A. Capaldi, Mark A. Robinson, Andrew J. Baron e Nicola J. Stonehouse. "RNA Multimerisation in the DNA Packaging Motor of Bacteriophage φ29". Journal of Theoretical Medicine 6, n. 2 (2005): 127–34. http://dx.doi.org/10.1080/10273660500149802.

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The use of bacteriophages as experimental tools allows the investigation of interactions between components at the molecular level that are often not possible in more complex virus systems. The bacteriophage φ29 acts as a molecular machine to package its own genomic DNA during viral assembly. Self-associating RNA molecules, called pRNA, have an essential role in the function of this machine. This paper reports the characterization of this self-association (which leads to multimerisation of wild-type and truncated variant pRNAs) by analytical ultracentrifugation (including determination of the partial specific volume of the pRNA), together with an investigation into the domains of the molecule important for multimerisation by the use of complementary DNA probes.

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35

Pleteneva, E. A., M. V. Bourkaltseva, O. V. Shaburova, S. V. Krylov, E. V. Pechnikova, O. S. Sokolova e V. N. Krylov. "TL, the new bacteriophage of Pseudomonas aeruginosa and its application for the search of halo-producing bacteriophages". Russian Journal of Genetics 47, n. 1 (gennaio 2011): 1–5. http://dx.doi.org/10.1134/s1022795411010091.

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36

Klucar, Lubos, Matej Stano e Matus Hajduk. "phiSITE: database of gene regulation in bacteriophages". Nucleic Acids Research 38, suppl_1 (7 novembre 2009): D366—D370. http://dx.doi.org/10.1093/nar/gkp911.

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37

Alam, Muntasir, Marufa Zerin Akhter, Mahmuda Yasmin, Chowdhury Rafiqul Ahsan e Jamalun Nessa. "Local bacteriophage isolates showed anti-Escherichia coliO157:H7 potency in an experimental ligated rabbit ileal loop model". Canadian Journal of Microbiology 57, n. 5 (maggio 2011): 408–15. http://dx.doi.org/10.1139/w11-020.

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Escherichia coli O157:H7 is considered among the most important recently emerged food-borne bacteria causing severe hemorrhagic diarrhea. Antibiotic treatment is not recommended as a prospective curative agent against this pathogen. Therefore, potency assessment of the local lytic phage isolates infecting E. coli O157:H7 as an alternate remedy to antibiotics was the principal concern of this study. Phage isolates against E. coli O157:H7 were checked by polymerase chain reaction for the presence of the virulence genes stx1 and stx2, and the safe phages were further screened in vitro for their capacity as biocontrol agents. Two bacteriophage strains, namely PAH6 and P2BH2, that had expressed potential antibacterial activity (P < 0.05) in vitro were selected for in vivo testing in ligated rabbit ileal loop models. Both phage isolates were capable of decreasing fluid accumulation in rabbit ileal loops along with reducing bacterial growth (r = 0.992). Combined application of the phages was found most satisfactory, reducing seven log cycles of bacterial growth. Consistent results in both in vivo and in vitro experiments demonstrate the applicability of bacteriophages as a rapid response tool against E. coli O157:H7. To our knowledge, this is the first successful application of the rabbit ileal loop test for therapeutic evaluation of bacteriophages.

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Pertics, Botond Zsombor, Dalma Szénásy, Dániel Dunai, Yannick Born, Lars Fieseler, Tamás Kovács e György Schneider. "Isolation of a Novel Lytic Bacteriophage against a Nosocomial Methicillin-Resistant Staphylococcus aureus Belonging to ST45". BioMed Research International 2020 (22 dicembre 2020): 1–10. http://dx.doi.org/10.1155/2020/5463801.

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Methicillin-resistant Staphylococcus aureus (MRSA) can cause a wide range of infections from mild to life-threatening conditions. Its enhanced antibiotic resistance often leads to therapeutic failures and therefore alternative eradication methods must be considered. Potential candidates to control MRSA infections are bacteriophages and their lytic enzymes, lysins. In this study, we isolated a bacteriophage against a nosocomial MRSA strain belonging to the ST45 epidemiologic group. The phage belonging to Caudovirales, Siphoviridae, showed a narrow host range and stable lytic activity without the emergence of resistant MRSA clones. Phylogenetic analysis showed that the newly isolated Staphylococcus phage R4 belongs to the Triavirus genus in Siphoviridae family. Genetic analysis of the 45 kb sequence of R4 revealed 69 ORFs. No remnants of mobile genetic elements and traces of truncated genes were observed. We have localized the lysin (N-acetylmuramoyl-L-alanine amidase) gene of the new phage that was amplified, cloned, expressed, and purified. Its activity was verified by zymogram analysis. Our findings could potentially be used to develop specific anti-MRSA bacteriophage- and phage lysin-based therapeutic strategies against major clonal lineages and serotypes.

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39

Kalmokofff, M. L., e D. E. Bradley. "Contractile-tailed bacteriophages adsorb toEscherichia coliO128ab lipopolysaccharide that is altered by large plasmids to provide receptors and lipopolysaccharide heterogeneity within the serogroup". Canadian Journal of Microbiology 41, n. 2 (1 febbraio 1995): 163–69. http://dx.doi.org/10.1139/m95-022.

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The verotoxigenic Escherichia coli strain H.I.8 (originally O128:B12, now not typeable) contained a ColB+M plasmid and two morphologically identical temperate bacteriophages (HI8A and HI8B). Both phages were O128ab specific, using the lipopolysaccharide O side chains of susceptible clinical isolates as receptors. SDS polyacrylamide gel electrophoresis with silver staining of O128ab lipopolysaccharide revealed four distinct types of ladder with different interband spacings. No specificity was found between ladder type and sensitivity to either phage. One of the numerous large plasmids present in O128ab isolates was found to modify the structure of the lipopolysaccharide O side chains to provide phage receptors.Key words: bacteriophage, plasmid, lipopolysaccharide, O antigen.

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40

Moon, Choi, Jeong, Sohn, Han e Oh. "Research Progress of M13 Bacteriophage-Based Biosensors". Nanomaterials 9, n. 10 (11 ottobre 2019): 1448. http://dx.doi.org/10.3390/nano9101448.

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Recently, new virus-based sensor systems that operate on M13 bacteriophage infrastructure have attracted considerable attention. These systems can detect a range of chemicals with excellent sensitivity and selectivity. Filaments consistent with M13 bacteriophages can be ordered by highly established forms of self-assembly. This allows M13 bacteriophages to build a homogeneous distribution and infiltrate the network structure of nanostructures under mild conditions. Phage display, involving the genetic engineering of M13 bacteriophages, is another strong feature of the M13 bacteriophage as a functional building block. The numerous genetic modification possibilities of M13 bacteriophages are clearly the key features, and far more applications are envisaged. This paper reviews the recent progress in the application of the M13 bacteriophage self-assembly structures through to sensor systems and discusses future M13 bacteriophage technology.

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41

Newlon, C. S., L. R. Lipchitz, I. Collins, A. Deshpande, R. J. Devenish, R. P. Green, H. L. Klein, T. G. Palzkill, R. B. Ren e S. Synn. "Analysis of a circular derivative of Saccharomyces cerevisiae chromosome III: a physical map and identification and location of ARS elements." Genetics 129, n. 2 (1 ottobre 1991): 343–57. http://dx.doi.org/10.1093/genetics/129.2.343.

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Abstract DNA was isolated from a circular derivative of chromosome III to prepare a library of recombinant plasmids enriched in chromosome III sequences. An ordered set of recombinant plasmids and bacteriophages carrying the contiguous 210-kilobase region of chromosome III between the HML and MAT loci was identified, and a complete restriction map was prepared with BamHI and EcoRI. Using the high frequency transformation assay and extensive subcloning, 13 ARS elements were mapped in the cloned region. Comparison of the physical maps of chromosome III from three strains revealed that the chromosomes differ in the number and positions of Ty elements and also show restriction site polymorphisms. A comparison of the physical map with the genetic map shows that meiotic recombination rates vary at least tenfold along the length of the chromosome.

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42

Zinder, Norton D. "Single-stranded DNA-containing bacteriophages". BioEssays 5, n. 2 (agosto 1986): 84–87. http://dx.doi.org/10.1002/bies.950050209.

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43

Karamoddini, M. Khajeh, B. S. Fazli-Bazzaz, F. Emamipour, M. Sabouri Ghannad, A. R. Jahanshahi, N. Saed e A. Sahebkar. "Antibacterial Efficacy of Lytic Bacteriophages against Antibiotic-ResistantKlebsiellaSpecies". Scientific World JOURNAL 11 (2011): 1332–40. http://dx.doi.org/10.1100/tsw.2011.114.

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Bacterial resistance to antibiotics is a leading and highly prevalent problem in the treatment of infectious diseases. Bacteriophages (phages) appear to be effective and safe alternatives for the treatment of resistant infections because of their specificity for bacterial species and lack of infectivity in eukaryotic cells. The present study aimed to isolate bacteriophages againstKlebsiellaspp. and evaluate their efficacy against antibiotic-resistant species. Seventy-two antibiotic-resistantKlebsiellaspp. were isolated from samples of patients who referred to the Ghaem Hospital (Mashhad, Iran). Lytic bacteriophages againstKlebsiellaspp. were isolated from wastewater of the septic tank of the same hospital. Bactericidal activity of phages against resistantKlebsiellaspp. was tested in both liquid (tube method; after 1 and 24 h of incubation) and solid (double-layer agar plate method; after 24 h of incubation) phases. In each method, three different concentrations of bacteriophages (low: <104PFU/mL, medium: 104–107PFU/mL, and high: > 107PFU/mL) were used. Bacteriophages showed promising bactericidal activity at all assessed concentrations, regardless of the test method and duration of incubation. Overall, bactericidal effects were augmented at higher concentrations. In the tube method, higher activity was observed after 24 h of incubation compared to the 1-h incubation. The bactericidal effects were also higher in the tube method compared to the double-layer agar plate method after 24 h of incubation. The findings of the present study suggest that bacteriophages possess effective bactericidal activity against resistantKlebsiellaspp. These bactericidal activities are influenced by phage concentration, duration of incubation, and test method.

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44

Gross, Michael. "Revived interest in bacteriophages". Current Biology 21, n. 8 (aprile 2011): R267—R270. http://dx.doi.org/10.1016/j.cub.2011.04.008.

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45

Carey-Smith, Gwyneth V., Craig Billington, Angela J. Cornelius, J. Andrew Hudson e Jack A. Heinemann. "Isolation and characterization of bacteriophages infectingSalmonellaspp." FEMS Microbiology Letters 258, n. 2 (maggio 2006): 182–86. http://dx.doi.org/10.1111/j.1574-6968.2006.00217.x.

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46

Shaburova, O. V., K. Hertveldt, D. M. A. de la Cruz, S. V. Krylov, E. A. Pleteneva, M. V. Bourkaltseva, R. Lavigne, G. Volckaert e V. N. Krylov. "Comparison of new giant bacteriophages OBP and Lu11 of soil pseudomonads with bacteriophages of the ϕKZ-supergroup of Pseudomonas aeruginosa". Russian Journal of Genetics 42, n. 8 (agosto 2006): 877–85. http://dx.doi.org/10.1134/s1022795406080059.

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47

Jarvis, A. W. "Bacteriophages of Lactic Acid Bacteria". Journal of Dairy Science 72, n. 12 (dicembre 1989): 3406–28. http://dx.doi.org/10.3168/jds.s0022-0302(89)79504-7.

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48

Fillol-Salom, Alfred, Ahlam Alsaadi, Jorge A. Moura de Sousa, Li Zhong, Kevin R. Foster, Eduardo P. C. Rocha, José R. Penadés, Hanne Ingmer e Jakob Haaber. "Bacteriophages benefit from generalized transduction". PLOS Pathogens 15, n. 7 (5 luglio 2019): e1007888. http://dx.doi.org/10.1371/journal.ppat.1007888.

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49

Kazibwe, George, Phionah Katami, Ruth Alinaitwe, Stephen Alafi, Ann Nanteza e Jesca Lukanga Nakavuma. "Bacteriophage activity against and characterisation of avian pathogenic Escherichia coli isolated from colibacillosis cases in Uganda". PLOS ONE 15, n. 12 (15 dicembre 2020): e0239107. http://dx.doi.org/10.1371/journal.pone.0239107.

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Avian Pathogenic Escherichia coli (APEC) cause colibacillosis leading to significant economic losses in the poultry industry. This laboratory-based study aimed at establishing stocks of avian pathogenic Escherichia coli lytic bacteriophages, for future development of cocktail products for colibacillosis management. The study determined the antibiotic susceptibility; phylogenetic categories, occurrence of selected serotypes and virulence genes among Escherichia coli stock isolates from chicken colibacillosis cases; and evaluated bacteriophage activity against the bacteria. Escherichia coli characterization was done through phenotypic and multiplex PCR methods. Bacteriophage isolation and preliminary characterization was achieved using the spot assay and overlay plating techniques. Fifty-six (56) isolates were phenotypically confirmed as E. coli and all exhibited resistance to at least one antimicrobial agent; while multi-drug resistance (at least three drugs) was encountered in 50 (89.3%) isolates. The APEC isolates mainly belonged to phylogroups A and D, representing 44.6% and 39.3%, respectively; whereas serotypes O1, O2 and O78 were not detected. Of the 56 isolates, 69.6% harbored at least one virulence gene, while 50% had at least four virulence genes; hence confirmed as APEC. Virulence genes, ompT and iutA were the most frequent in 33 (58.9%) and 32 (57.1%) isolates respectively; while iroN least occurred in 23 (41.1%) isolates. Seven lytic bacteriophages were isolated and their host range, at 1×108 PFU/ml, varied from 1.8% to 17.9% of the 56 APEC isolates, while the combined lytic spectrum was 25%. Phage stability was negatively affected by increasing temperatures with both UPEC04 and UPEC10 phages being undetectable at 70°C; whereas activity was detected between pH 2 and 12. The high occurrence of APEC isolates resistant against the commonly used antibiotics supports the need for alternative strategies of bacterial infections control in poultry. The low host range exhibited by the phages necessitates search for more candidates before in-depth phage characterization and application.

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Rahmat Ullah, Sidra, Saadia Andleeb, Taskeen Raza, Muhsin Jamal e Khalid Mehmood. "Effectiveness of a Lytic Phage SRG1 against Vancomycin-ResistantEnterococcus faecalisin Compost and Soil". BioMed Research International 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/9351017.

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Nosocomial infections caused by vancomycin-resistantEnterococcushave become a major problem. Bacteriophage therapy is proposed as a potential alternative therapy. Bacteriophages are viruses that infect bacteria and are ubiquitous in nature. Lytic bacteriophage was isolated from sewage water that infects VREF, the causative agent of endocarditis, bacteraemia, and urinary tract infections (UTIs). The phage produced clear plaques with unique clear morphology and well-defined boundaries. TEM results of phage revealed it to be108±0.2 nm long and90±0.5 nm wide. The characterization of bacteriophage revealed that infection process of phage was calcium and magnesium dependent and phage titers were highest under optimum conditions for VREF, with an optimal temperature range of 37–50°C. The maximum growth was observed at 37°C, hence having 100% viability. The latent period for phage was small with a burst size of 512 viral particles per bacterial cell. The phage was tested against various clinical strains and results proved it to be host specific. It can be used as a potential therapeutic agent for VREF infections. The phage efficiently eradicated VREF inoculated in cattle compost, poultry compost, and a soil sample which makes it a potential agent for clearing compost and soil sample.

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