Complete genome sequence of a Staphylococcus epidermidis bacteriophage isolated from the anterior nares of humans

We report here the complete genome sequence of a virulent Staphylococcus epidermidis siphophage, phage 6ec, isolated from the anterior nares of a human. This viral genome is 93,794 bp in length, with a 3' overhang cos site of 10 nucleotides, and it codes for 142 putative open reading frames

Predicting promoters in phage genomes using machine learning models

The renewed interest in phages as antibacterial agents has led to the exponentially growing number of sequenced phage genomes. Therefore, the development of novel bioinformatics methods to automate and facilitate phage genome annotation is of utmost importance. The most difficult step of phage genome annotation is the identification of promoters. As the existing methods for predicting promoters are not well suited for phages, we used machine learning models for locating promoters in phage genomes. Several models were created, using different algorithms and datasets, which consisted of known phage promoter and non-promoter sequences. All models showed good performance, but the ANN model provided better results for the smaller dataset (92% of accuracy, 89% of precision and 87% of recall) and the SVM model returned better results for the larger dataset (93% of accuracy, 91% of precision and 80% of recall). Both models were applied to the genome of Pseudomonas phage phiPsa17 and were able to identify both types of promoters, host and phage, found in phage genomes.This study was supported by the Portuguese Foundation for Science andTechnology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit and theProject POCI-01-0145-FEDER-029628. This work was also supported by BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fundunder the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Complete Genome Sequences of Pseudomonas fluorescens Bacteriophages Isolated from Freshwater Samples in Omaha, Nebraska

The complete genome sequences of four Pseudomonas fluorescens bacteriophages, UNO-SLW1 to UNO-SLW4, isolated from freshwater samples, are 39,092 to 39,215 bp long. The genomes are highly similar (identity, \u3e0.995) but dissimilar from that of Pseudomonas phage Pf-10 (the closest relative, 0.685 to 0.686 identity), with 48 to 49 protein-coding genes and 66 regulatory sites predicted

Characterization of the newly isolated lytic bacteriophages KTN6 and KT28 and their efficacy against Pseudomonas aeruginosa biofilm

We here describe two novel lytic phages, KT28 and KTN6, infecting Pseudomonas aeruginosa, isolated from a sewage sample from an irrigated field near Wroclaw, in Poland. Both viruses show characteristic features of Pbunalikevirus genus within the Myoviridae family with respect to shape and size of head/tail, as well as LPS host receptor recognition. Genome analysis confirmed the similarity to other PB1-related phages, ranging between 48 and 96%. Pseudomonas phage KT28 has a genome size of 66,381 bp and KTN6 of 65,994 bp. The latent period, burst size, stability and host range was determined for both viruses under standard laboratory conditions. Biofilm eradication efficacy was tested on peg-lid plate assay and PET membrane surface. Significant reduction of colony forming units was observed (70-90%) in 24 h to 72 h old Pseudomonas aeruginosa PAO1 biofilm cultures for both phages. Furthermore, a pyocyanin and pyoverdin reduction tests reveal that tested phages lowers the amount of both secreted dyes in 48-72 h old biofilms. Diffusion and goniometry experiments revealed the increase of diffusion rate through the biofilm matrix after phage application. These characteristics indicate these phages could be used to prevent Pseudomonas aeruginosa infections and biofilm formation. It was also shown, that PB1-related phage treatment of biofilm caused the emergence of stable phage-resistant mutants growing as small colony variants

Complete genome sequence of the lytic Pseudomonas fluorescens phage ϕIBB-PF7A

<p>Abstract</p> <p>Background</p> <p>Phage ϕIBB-PF7A is a T7-like bacteriophage capable of infecting several <it>Pseudomonas fluorescens </it>dairy isolates and is extremely efficient in lysing this bacterium even when growing in biofilms attached to surfaces. This work describes the complete genome sequence of this phage.</p> <p>Results</p> <p>The genome consists of a linear double-stranded DNA of 40,973 bp, with 985 bp long direct terminal repeats and a GC content of approximately 56%. There are 52 open reading frames which occupy 94.6% of the genome ranging from 137 to 3995 nucleotides. Twenty eight (46.7%) of the proteins encoded by this virus exhibit sequence similarity to coliphage T7 proteins while 34 (81.0%) are similar to proteins of <it>Pseudomonas </it>phage gh-1.</p> <p>Conclusions</p> <p>That this phage is closely related to <it>Pseudomonas putida </it>phage gh-1 and coliphage T7 places it in the "T7-like viruses" genus of the subfamily <it>Autographivirinae </it>within the family <it>Podoviridae</it>. Compared to the genome of gh-1, the sequence of ϕIBB-PF7A is longer and contains more genes with unassigned function and lacks a few potentially essential and non-essential T7 genes, such as gene1.1, 3.8, and 7.</p

The genome and proteome of the Kluyvera bacteriophage Kvp1 – another member of the T7-like Autographivirinae

BACKGROUND: Kluyvera, a genus within the family Enterobacteriaceae, is an infrequent cause of human infections. Bacteriophage Kvp1, the only bacteriophage isolated for one of its species, Kluyvera cryocrescens, is a member of the viral family Podoviridae. RESULTS: The genome of Kvp1, the first Kluyvera cryocrescens-specific bacteriophage, was sequenced using pyrosequencing (454 technology) at the McGill University and Genome Québec Innovation Centre. The two contigs were closed using PCR and the sequence of the terminal repeats completed by primer walking off the phage DNA. The phage structural proteome was investigated by SDS-PAGE and mass spectrometry. CONCLUSION: At 39,472 bp, the annotated genome revealed a closer relationship to coliphage T3 than T7 with Kvp1 containing homologs to T3 early proteins S-adenosyl-L-methionine hydrolase (0.3) and protein kinase (0.7). The quantitative nature of the relationships between Kvp1 and the other members of the T7-like virus genus (T7, T3, φA1122, φYeO3-12, Berlin, K1F, VP4 and gh-1) was confirmed using CoreGenes

Salmonella Typhimurium-specific bacteriophage ΦSH19 and the origins of species specificity in the Vi01-like phage family

<p>Abstract</p> <p>Background</p> <p>Whole genome sequencing of bacteriophages suitable for biocontrol of pathogens in food products is a pre-requisite to any phage-based intervention procedure. Trials involving the biosanitization of <it>Salmonella </it>Typhimurium in the pig production environment identified one such candidate, ΦSH19.</p> <p>Results</p> <p>This phage was sequenced and analysis of its 157,785 bp circular dsDNA genome revealed a number of interesting features. ΦSH19 constitutes another member of the recently-proposed <it>Myoviridae </it>Vi01-like family of phages, containing <it>S</it>. Typhi-specific Vi01 and <it>Shigella</it>-specific SboM-AG3. At the nucleotide level ΦSH19 is highly similar to phage Vi01 (80-98% pairwise identity over the length of the genome), with the major differences lying in the region associated with host-range determination. Analyses of the proteins encoded within this region by ΦSH19 revealed a cluster of three putative tail spikes. Of the three tail spikes, two have protein domains associated with the pectate lyase family of proteins (Tsp2) and P22 tail spike family (Tsp3) with the prospect that these enable <it>Salmonella </it>O antigen degradation. Tail spike proteins of Vi01 and SboM-AG3 are predicted to contain conserved right-handed parallel β-helical structures but the internal protein domains are varied allowing different host specificities.</p> <p>Conclusions</p> <p>The addition or exchange of tail spike protein modules is a major contributor to host range determination in the Vi01-like phage family.</p

ОСОБЕННОСТИ МОЛЕКУЛЯРНО-ГЕНЕТИЧЕСКОЙ ОРГАНИЗАЦИИ ФАГА РF-10

The analysis of a full nucleotide sequence of bacteriophage Pf-10 as a key constituent of biopesticide “Multiphage” has revealed that its unique genome is composed of a DNA fragment of broad range host phage Phi-S1, where the determinants governing the synthesis of early proteins are localized, and of the DNA fragment of narrow range host phage phiIBB-PF7A containing the genes responsible for the synthesis of late proteins. Low homology of individual genetic determinants and encoded amino acid sequences (namely, the genes determining the synthesis of tail proteins) with those of phages Phi-S1 or phiIBB-PF7A evidences the mutations that emerge in the course of the phage Pf-10 genome formation and are capable to affect its vital important functions.В результате анализа полной нуклеотидной последовательности бактериофага Pf-10, входящего в состав биопестицида «Мультифаг», установлено, что его геном является уникальным и состоит из фрагмента ДНК фага широкого круга хозяев Phi-S1, в пределах которого локализованы детерминанты, определяющие синтез ранних белков,и фрагмента ДНК фага узкого круга хозяев phiIBB-PF7A, содержащего гены, детерминирующие синтез поздних белков.Низкая гомология отдельных генетических детерминант и кодируемых ими аминокислотных последовательностей (в частности, генов, определяющих синтез белков отростка) с таковыми фагов � Phi-S1 или phiIBB-PF7A свиде-Phi-свиде--S1 свидетельствует о мутационных изменениях, возникших в процессе становления фагового генома Pf-10 и способных повлиять на его жизненно важные функции

Modular control of multiple pathways using engineered orthogonal T7 polymerases

Synthetic genetic sensors and circuits enable programmable control over the timing and conditions of gene expression. They are being increasingly incorporated into the control of complex, multigene pathways and cellular functions. Here, we propose a design strategy to genetically separate the sensing/circuitry functions from the pathway to be controlled. This separation is achieved by having the output of the circuit drive the expression of a polymerase, which then activates the pathway from polymerase-specific promoters. The sensors, circuits and polymerase are encoded together on a ‘controller’ plasmid. Variants of T7 RNA polymerase that reduce toxicity were constructed and used as scaffolds for the construction of four orthogonal polymerases identified via part mining that bind to unique promoter sequences. This set is highly orthogonal and induces cognate promoters by 8- to 75-fold more than off-target promoters. These orthogonal polymerases enable four independent channels linking the outputs of circuits to the control of different cellular functions. As a demonstration, we constructed a controller plasmid that integrates two inducible systems, implements an AND logic operation and toggles between metabolic pathways that change Escherichia coli green (deoxychromoviridans) and red (lycopene). The advantages of this organization are that (i) the regulation of the pathway can be changed simply by introducing a different controller plasmid, (ii) transcription is orthogonal to host machinery and (iii) the pathway genes are not transcribed in the absence of a controller and are thus more easily carried without invoking evolutionary pressure.United States. Office of Naval Research (Award number N00014-10-1-0245)National Science Foundation (U.S.). (CCF-0943385)National Institutes of Health (U.S.) (AI067699)National Science Foundation (U.S.). Graduate Research FellowshipAmerican Society for Engineering Education. National Defense Science and Engineering Graduate FellowshipHertz Foundation. Graduate Fellowshi

Characterization and genome analysis of Escherichia phage fBC-Eco01, isolated from wastewater in Tunisia

The rise of antibiotic resistance in bacterial strains has led to vigorous exploration for alternative treatments. To this end, phage therapy has been revisited, and it is gaining increasing attention, as it may represent an efficient alternative for treating multiresistant pathogenic bacteria. Phage therapy is considered safe, and phages do not infect eukaryotic cells. There have been many studies investigating phage-host bacteria interactions and the ability of phages to target specific hosts. Escherichia coli is the causative agent of a multitude of infections, ranging from urinary tract infections to sepsis, with growing antibiotic resistance. In this study, we characterized the Escherichia phage fBC-Eco01, which was isolated from a water sample collected at Oued, Tunis. Electron microscopy showed that fBC-Eco01 phage particles have siphovirus morphology, with an icosahedral head of 61 ± 3 nm in diameter and a non-contractile tail of 94 ± 2 nm in length and 12 ± 0.9 nm in width. The genome of fBC-Eco01 is a linear double-stranded DNA of 43.466 bp with a GC content of 50.4%. Comparison to databases allowed annotation of the functions to 39 of the 78 predicted gene products. A single-step growth curve revealed that fBC-Eco01 has a latent period of 30 minutes and a burst size of 175 plaque-forming units (PFU) per infected cell. Genomic analysis indicated that fBC-Eco01 is a member of the subfamily Guernseyvirinae. It is most closely related to a group of phages of the genus Kagunavirus that infect Enterobacter, Raoultella, and Escherichia strains.Peer reviewe