Viruses whose hosts are bacterial cells.
Virulent bacteriophage and type species of the genus T4-like phages, in the family MYOVIRIDAE. It infects E. coli and is the best known of the T-even phages. Its virion contains linear double-stranded DNA, terminally redundant and circularly permuted.
A temperate inducible phage and type species of the genus lambda-like viruses, in the family SIPHOVIRIDAE. Its natural host is E. coli K12. Its VIRION contains linear double-stranded DNA with single-stranded 12-base 5' sticky ends. The DNA circularizes on infection.
Viruses whose host is Escherichia coli.
Virulent bacteriophage and type species of the genus T7-like phages, in the family PODOVIRIDAE, that infects E. coli. It consists of linear double-stranded DNA, terminally redundant, and non-permuted.
The phenomenon by which a temperate phage incorporates itself into the DNA of a bacterial host, establishing a kind of symbiotic relation between PROPHAGE and bacterium which results in the perpetuation of the prophage in all the descendants of the bacterium. Upon induction (VIRUS ACTIVATION) by various agents, such as ultraviolet radiation, the phage is released, which then becomes virulent and lyses the bacterium.
A series of 7 virulent phages which infect E. coli. The T-even phages T2, T4; (BACTERIOPHAGE T4), and T6, and the phage T5 are called "autonomously virulent" because they cause cessation of all bacterial metabolism on infection. Phages T1, T3; (BACTERIOPHAGE T3), and T7; (BACTERIOPHAGE T7) are called "dependent virulent" because they depend on continued bacterial metabolism during the lytic cycle. The T-even phages contain 5-hydroxymethylcytosine in place of ordinary cytosine in their DNA.
A temperate coliphage, in the genus Mu-like viruses, family MYOVIRIDAE, composed of a linear, double-stranded molecule of DNA, which is able to insert itself randomly at any point on the host chromosome. It frequently causes a mutation by interrupting the continuity of the bacterial OPERON at the site of insertion.
Virulent bacteriophage and sole member of the genus Cystovirus that infects Pseudomonas species. The virion has a segmented genome consisting of three pieces of doubled-stranded DNA and also a unique lipid-containing envelope.
Deoxyribonucleic acid that makes up the genetic material of viruses.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
The type species of the genus MICROVIRUS. A prototype of the small virulent DNA coliphages, it is composed of a single strand of supercoiled circular DNA, which on infection, is converted to a double-stranded replicative form by a host enzyme.
Proteins found in any species of virus.
A species of temperate bacteriophage in the genus P2-like viruses, family MYOVIRIDAE, which infects E. coli. It consists of linear double-stranded DNA with 19-base sticky ends.
Temperate bacteriophage of the genus INOVIRUS which infects enterobacteria, especially E. coli. It is a filamentous phage consisting of single-stranded DNA and is circularly permuted.
Viruses whose nucleic acid is DNA.
Bacteriophage in the genus T7-like phages, of the family PODOVIRIDAE, which is very closely related to BACTERIOPHAGE T7.
A technique of bacterial typing which differentiates between bacteria or strains of bacteria by their susceptibility to one or more bacteriophages.
A species of temperate bacteriophage in the genus P1-like viruses, family MYOVIRIDAE, which infects E. coli. It is the largest of the COLIPHAGES and consists of double-stranded DNA, terminally redundant, and circularly permuted.
Viruses whose host is Salmonella. A frequently encountered Salmonella phage is BACTERIOPHAGE P22.
A family of BACTERIOPHAGES and ARCHAEAL VIRUSES which are characterized by long, non-contractile tails.
Bacteriophages whose genetic material is RNA, which is single-stranded in all except the Pseudomonas phage phi 6 (BACTERIOPHAGE PHI 6). All RNA phages infect their host bacteria via the host's surface pili. Some frequently encountered RNA phages are: BF23, F2, R17, fr, PhiCb5, PhiCb12r, PhiCb8r, PhiCb23r, 7s, PP7, Q beta phage, MS2 phage, and BACTERIOPHAGE PHI 6.
The functional hereditary units of VIRUSES.
Rupture of bacterial cells due to mechanical force, chemical action, or the lytic growth of BACTERIOPHAGES.
Bacteriophage and type species in the genus Tectivirus, family TECTIVIRIDAE. They are specific for Gram-negative bacteria.
Viruses whose host is Pseudomonas. A frequently encountered Pseudomonas phage is BACTERIOPHAGE PHI 6.
Viruses whose host is Staphylococcus.
Viruses whose host is Bacillus. Frequently encountered Bacillus phages include bacteriophage phi 29 and bacteriophage phi 105.
A family of bacteriophages which are characterized by short, non-contractile tails.
Viruses whose host is Streptococcus.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Proteins found in the tail sections of DNA and RNA viruses. It is believed that these proteins play a role in directing chain folding and assembly of polypeptide chains.
A bacteriophage genus of the family LEVIVIRIDAE, whose viruses contain the short version of the genome and have a separate gene for cell lysis.
The complete genetic complement contained in a DNA or RNA molecule in a virus.
The adhesion of gases, liquids, or dissolved solids onto a surface. It includes adsorptive phenomena of bacteria and viruses onto surfaces as well. ABSORPTION into the substance may follow but not necessarily.
The folding of an organism's DNA molecule into a compact, orderly structure that fits within the limited space of a CELL or VIRUS PARTICLE.
The process by which a DNA molecule is duplicated.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
Genomes of temperate BACTERIOPHAGES integrated into the DNA of their bacterial host cell. The prophages can be duplicated for many cell generations until some stimulus induces its activation and virulence.
A genus of filamentous bacteriophages of the family INOVIRIDAE. Organisms of this genus infect enterobacteria, PSEUDOMONAS; VIBRIO; and XANTHOMONAS.
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
A subdiscipline of genetics which deals with the genetic mechanisms and processes of microorganisms.
Enzymes that catalyze DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesized. (From Enzyme Nomenclature, 1992).
Specific loci on both the bacterial DNA (attB) and the phage DNA (attP) which delineate the sites where recombination takes place between them, as the phage DNA becomes integrated (inserted) into the BACTERIAL DNA during LYSOGENY.
Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.
Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Method for measuring viral infectivity and multiplication in CULTURED CELLS. Clear lysed areas or plaques develop as the VIRAL PARTICLES are released from the infected cells during incubation. With some VIRUSES, the cells are killed by a cytopathic effect; with others, the infected cells are not killed but can be detected by their hemadsorptive ability. Sometimes the plaque cells contain VIRAL ANTIGENS which can be measured by IMMUNOFLUORESCENCE.
The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.
A species of gram-positive bacteria that is a common soil and water saprophyte.
The outer protein protective shell of a virus, which protects the viral nucleic acid.
The transfer of bacterial DNA by phages from an infected bacterium to another bacterium. This also refers to the transfer of genes into eukaryotic cells by viruses. This naturally occurring process is routinely employed as a GENE TRANSFER TECHNIQUE.
A single chain of deoxyribonucleotides that occurs in some bacteria and viruses. It usually exists as a covalently closed circle.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
A family of bacteriophages containing one genus (Cystovirus) with one member (BACTERIOPHAGE PHI 6).
A species of filamentous Pseudomonas phage in the genus INOVIRUS, family INOVIRIDAE.
Enzymes which catalyze the hydrolases of ester bonds within DNA. EC 3.1.-.
An antibiotic first isolated from cultures of Streptomyces venequelae in 1947 but now produced synthetically. It has a relatively simple structure and was the first broad-spectrum antibiotic to be discovered. It acts by interfering with bacterial protein synthesis and is mainly bacteriostatic. (From Martindale, The Extra Pharmacopoeia, 29th ed, p106)
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
Proteins that form the CAPSID of VIRUSES.
Any method used for determining the location of and relative distances between genes on a chromosome.
An order comprising three families of tailed bacteriophages: MYOVIRIDAE; PODOVIRIDAE; and SIPHOVIRIDAE.
Ribonucleic acid that makes up the genetic material of viruses.
Stable phosphorus atoms that have the same atomic number as the element phosphorus, but differ in atomic weight. P-31 is a stable phosphorus isotope.
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
Proteins found in any species of bacterium.
DNA-dependent DNA polymerases found in bacteria, animal and plant cells. During the replication process, these enzymes catalyze the addition of deoxyribonucleotide residues to the end of a DNA strand in the presence of DNA as template-primer. They also possess exonuclease activity and therefore function in DNA repair.
A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.
A single-stranded DNA-dependent RNA polymerase that functions to initiate, or prime, DNA synthesis by synthesizing oligoribonucleotide primers. EC 2.7.7.-.
Treatment of diseases with biological materials or biological response modifiers, such as the use of GENES; CELLS; TISSUES; organs; SERUM; VACCINES; and humoral agents.
Electron microscopy involving rapid freezing of the samples. The imaging of frozen-hydrated molecules and organelles permits the best possible resolution closest to the living state, free of chemical fixatives or stains.
The properties of a pathogen that makes it capable of infecting one or more specific hosts. The pathogen can include PARASITES as well as VIRUSES; BACTERIA; FUNGI; or PLANTS.
Enzymes that catalyze the incorporation of deoxyribonucleotides into a chain of DNA. EC 2.7.7.-.
Refuse liquid or waste matter carried off by sewers.
The sum of the weight of all the atoms in a molecule.
The functional hereditary units of BACTERIA.
Macromolecular molds for the synthesis of complementary macromolecules, as in DNA REPLICATION; GENETIC TRANSCRIPTION of DNA to RNA, and GENETIC TRANSLATION of RNA into POLYPEPTIDES.
A broad category of viral proteins that play indirect roles in the biological processes and activities of viruses. Included here are proteins that either regulate the expression of viral genes or are involved in modifying host cell functions. Many of the proteins in this category serve multiple functions.
Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)
The rate dynamics in chemical or physical systems.
Viral proteins that are components of the mature assembled VIRUS PARTICLES. They may include nucleocapsid core proteins (gag proteins), enzymes packaged within the virus particle (pol proteins), and membrane components (env proteins). These do not include the proteins encoded in the VIRAL GENOME that are produced in infected cells but which are not packaged in the mature virus particle,i.e. the so called non-structural proteins (VIRAL NONSTRUCTURAL PROTEINS).
In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.
Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.
Tungsten hydroxide oxide phosphate. A white or slightly yellowish-green, slightly efflorescent crystal or crystalline powder. It is used as a reagent for alkaloids and many other nitrogen bases, for phenols, albumin, peptone, amino acids, uric acid, urea, blood, and carbohydrates. (From Merck Index, 11th ed)
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
Disruption of the secondary structure of nucleic acids by heat, extreme pH or chemical treatment. Double strand DNA is "melted" by dissociation of the non-covalent hydrogen bonds and hydrophobic interactions. Denatured DNA appears to be a single-stranded flexible structure. The effects of denaturation on RNA are similar though less pronounced and largely reversible.
A sequence of successive nucleotide triplets that are read as CODONS specifying AMINO ACIDS and begin with an INITIATOR CODON and end with a stop codon (CODON, TERMINATOR).
That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.
Biologically active DNA which has been formed by the in vitro joining of segments of DNA from different sources. It includes the recombination joint or edge of a heteroduplex region where two recombining DNA molecules are connected.
Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.
A group of methylazirinopyrroloindolediones obtained from certain Streptomyces strains. They are very toxic antibiotics used as ANTINEOPLASTIC AGENTS in some solid tumors. PORFIROMYCIN and MITOMYCIN are the most useful members of the group.
Catalyze the joining of preformed ribonucleotides or deoxyribonucleotides in phosphodiester linkage during genetic processes. EC 6.5.1.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
Viruses whose host is one or more Mycobacterium species. They include both temperate and virulent types.
Any of the covalently closed DNA molecules found in bacteria, many viruses, mitochondria, plastids, and plasmids. Small, polydisperse circular DNA's have also been observed in a number of eukaryotic organisms and are suggested to have homology with chromosomal DNA and the capacity to be inserted into, and excised from, chromosomal DNA. It is a fragment of DNA formed by a process of looping out and deletion, containing a constant region of the mu heavy chain and the 3'-part of the mu switch region. Circular DNA is a normal product of rearrangement among gene segments encoding the variable regions of immunoglobulin light and heavy chains, as well as the T-cell receptor. (Riger et al., Glossary of Genetics, 5th ed & Segen, Dictionary of Modern Medicine, 1992)
A group of enzymes catalyzing the endonucleolytic cleavage of DNA. They include members of EC 3.1.21.-, EC 3.1.22.-, EC 3.1.23.- (DNA RESTRICTION ENZYMES), EC 3.1.24.- (DNA RESTRICTION ENZYMES), and EC 3.1.25.-.
The effects of ionizing and nonionizing radiation upon living organisms, organs and tissues, and their constituents, and upon physiologic processes. It includes the effect of irradiation on food, drugs, and chemicals.
Recombinases that insert exogenous DNA into the host genome. Examples include proteins encoded by the POL GENE of RETROVIRIDAE and also by temperate BACTERIOPHAGES, the best known being BACTERIOPHAGE LAMBDA.
The regulatory elements of an OPERON to which activators or repressors bind thereby effecting the transcription of GENES in the operon.
The assembly of VIRAL STRUCTURAL PROTEINS and nucleic acid (VIRAL DNA or VIRAL RNA) to form a VIRUS PARTICLE.
Enzymes that catalyze the release of mononucleotides by the hydrolysis of the terminal bond of deoxyribonucleotide or ribonucleotide chains.
Proteins that catalyze the unwinding of duplex DNA during replication by binding cooperatively to single-stranded regions of DNA or to short regions of duplex DNA that are undergoing transient opening. In addition DNA helicases are DNA-dependent ATPases that harness the free energy of ATP hydrolysis to translocate DNA strands.
A non-pathogenic species of LACTOCOCCUS found in DAIRY PRODUCTS and responsible for the souring of MILK and the production of LACTIC ACID.
A large family of lytic bacteriophages infecting enterobacteria; SPIROPLASMA; BDELLOVIBRIO; and CHLAMYDIA. It contains four genera: MICROVIRUS; Spiromicrovirus; Bdellomicrovirus; and Chlamydiamicrovirus.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
Enzymes that catalyze the template-directed incorporation of ribonucleotides into an RNA chain. EC 2.7.7.-.
A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
The infective system of a virus, composed of the viral genome, a protein core, and a protein coat called a capsid, which may be naked or enclosed in a lipoprotein envelope called the peplos.
Proteins obtained from ESCHERICHIA COLI.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
A tentative species in the genus lambda-like viruses, family SIPHOVIRIDAE.
Any of the processes by which cytoplasmic factors influence the differential control of gene action in viruses.
A family of icosahedral, lipid-containing, non-enveloped bacteriophages containing one genus (Corticovirus).
Enzymes that catalyze the hydrolysis of the internal bonds and thereby the formation of polynucleotides or oligonucleotides from ribo- or deoxyribonucleotide chains. EC 3.1.-.
A family of lipid-containing bacteriophages with double capsids which infect both gram-negative and gram-positive bacteria. It has one genus, Tectivirus.
A basic enzyme that is present in saliva, tears, egg white, and many animal fluids. It functions as an antibacterial agent. The enzyme catalyzes the hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in peptidoglycan and between N-acetyl-D-glucosamine residues in chitodextrin. EC
An autolytic enzyme bound to the surface of bacterial cell walls. It catalyzes the hydrolysis of the link between N-acetylmuramoyl residues and L-amino acid residues in certain cell wall glycopeptides, particularly peptidoglycan. EC
Specific molecular components of the cell capable of recognizing and interacting with a virus, and which, after binding it, are capable of generating some signal that initiates the chain of events leading to the biological response.
A genus of gram-negative, aerobic, rod-shaped bacteria widely distributed in nature. Some species are pathogenic for humans, animals, and plants.
Phosphate esters of THYMIDINE in N-glycosidic linkage with ribose or deoxyribose, as occurs in nucleic acids. (From Dorland, 28th ed, p1154)
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.
A plasmid whose presence in the cell, either extrachromosomal or integrated into the BACTERIAL CHROMOSOME, determines the "sex" of the bacterium, host chromosome mobilization, transfer via conjugation (CONJUGATION, GENETIC) of genetic material, and the formation of SEX PILI.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
Mutation process that restores the wild-type PHENOTYPE in an organism possessing a mutationally altered GENOTYPE. The second "suppressor" mutation may be on a different gene, on the same gene but located at a distance from the site of the primary mutation, or in extrachromosomal genes (EXTRACHROMOSOMAL INHERITANCE).
Electrophoresis in which agar or agarose gel is used as the diffusion medium.
DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
The meaning ascribed to the BASE SEQUENCE with respect to how it is translated into AMINO ACID SEQUENCE. The start, stop, and order of amino acids of a protein is specified by consecutive triplets of nucleotides called codons (CODON).
A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.
A pyrimidine base that is a fundamental unit of nucleic acids.
A phenomenon in which infection by a first virus results in resistance of cells or tissues to infection by a second, unrelated virus.
Centrifugation using a rotating chamber of large capacity in which to separate cell organelles by density-gradient centrifugation. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.
Change brought about to an organisms genetic composition by unidirectional transfer (TRANSFECTION; TRANSDUCTION, GENETIC; CONJUGATION, GENETIC, etc.) and incorporation of foreign DNA into prokaryotic or eukaryotic cells by recombination of part or all of that DNA into the cell's genome.
Genes which regulate or circumscribe the activity of other genes; specifically, genes which code for PROTEINS or RNAs which have GENE EXPRESSION REGULATION functions.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)
Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.
An enzyme responsible for producing a species-characteristic methylation pattern on adenine residues in a specific short base sequence in the host cell DNA. The enzyme catalyzes the methylation of DNA adenine in the presence of S-adenosyl-L-methionine to form DNA containing 6-methylaminopurine and S-adenosyl-L-homocysteine. EC
The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.
A toxin produced by SHIGELLA DYSENTERIAE. It is the prototype of class of toxins that inhibit protein synthesis by blocking the interaction of ribosomal RNA; (RNA, RIBOSOMAL) with PEPTIDE ELONGATION FACTORS.
Bacterial proteins that are used by BACTERIOPHAGES to incorporate their DNA into the DNA of the "host" bacteria. They are DNA-binding proteins that function in genetic recombination as well as in transcriptional and translational regulation.
Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.
A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. aeruginosa is a major agent of nosocomial infection.
Enzymes that catalyze the hydrolysis of ester bonds within RNA. EC 3.1.-.
The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).
An enzyme that catalyzes the conversion of linear RNA to a circular form by the transfer of the 5'-phosphate to the 3'-hydroxyl terminus. It also catalyzes the covalent joining of two polyribonucleotides in phosphodiester linkage. EC
Bacteriocins elaborated by strains of Escherichia coli and related species. They are proteins or protein-lipopolysaccharide complexes lethal to other strains of the same species.
A group of ribonucleotides (up to 12) in which the phosphate residues of each ribonucleotide act as bridges in forming diester linkages between the ribose moieties.
A semisynthetic antibiotic produced from Streptomyces mediterranei. It has a broad antibacterial spectrum, including activity against several forms of Mycobacterium. In susceptible organisms it inhibits DNA-dependent RNA polymerase activity by forming a stable complex with the enzyme. It thus suppresses the initiation of RNA synthesis. Rifampin is bactericidal, and acts on both intracellular and extracellular organisms. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p1160)
An enzyme that catalyzes the transfer of a phosphate group to the 5'-terminal hydroxyl groups of DNA and RNA. EC
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.
A member of the alkali metals. It has an atomic symbol Cs, atomic number 50, and atomic weight 132.91. Cesium has many industrial applications, including the construction of atomic clocks based on its atomic vibrational frequency.
Organisms, biological agents, or biologically-derived agents used strategically for their positive or adverse effect on the physiology and/or reproductive health of other organisms.
Viruses whose genetic material is RNA.
Presence of warmth or heat or a temperature notably higher than an accustomed norm.
The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
Proteins which maintain the transcriptional quiescence of specific GENES or OPERONS. Classical repressor proteins are DNA-binding proteins that are normally bound to the OPERATOR REGION of an operon, or the ENHANCER SEQUENCES of a gene until a signal occurs that causes their release.
Insertion of viral DNA into host-cell DNA. This includes integration of phage DNA into bacterial DNA; (LYSOGENY); to form a PROPHAGE or integration of retroviral DNA into cellular DNA to form a PROVIRUS.
A genus of gram-positive, coccoid bacteria mainly isolated from milk and milk products. These bacteria are also found in plants and nonsterile frozen and dry foods. Previously thought to be a member of the genus STREPTOCOCCUS (group N), it is now recognized as a separate genus.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
Unstable isotopes of phosphorus that decay or disintegrate emitting radiation. P atoms with atomic weights 28-34 except 31 are radioactive phosphorus isotopes.
The sequential location of genes on a chromosome.
The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.
The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
Ability of a microbe to survive under given conditions. This can also be related to a colony's ability to replicate.
A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.
The mechanism by which latent viruses, such as genetically transmitted tumor viruses (PROVIRUSES) or PROPHAGES of lysogenic bacteria, are induced to replicate and then released as infectious viruses. It may be effected by various endogenous and exogenous stimuli, including B-cell LIPOPOLYSACCHARIDES, glucocorticoid hormones, halogenated pyrimidines, IONIZING RADIATION, ultraviolet light, and superinfecting viruses.
A genus of BACILLACEAE that are spore-forming, rod-shaped cells. Most species are saprophytic soil forms with only a few species being pathogenic.
The reformation of all, or part of, the native conformation of a nucleic acid molecule after the molecule has undergone denaturation.
A toxin produced by certain pathogenic strains of ESCHERICHIA COLI such as ESCHERICHIA COLI O157. It shares 50-60% homology with SHIGA TOXIN and SHIGA TOXIN 1.
A purine or pyrimidine base bonded to a DEOXYRIBOSE containing a bond to a phosphate group.
A verocytotoxin-producing serogroup belonging to the O subfamily of Escherichia coli which has been shown to cause severe food-borne disease. A strain from this serogroup, serotype H7, which produces SHIGA TOXINS, has been linked to human disease outbreaks resulting from contamination of foods by E. coli O157 from bovine origin.
Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.
The relationships of groups of organisms as reflected by their genetic makeup.
A species of filamentous phage in the genus INOVIRUS, family INOVIRIDAE. They are specific for enterobacteria that contain an IncN plasmid.
A genus of gram-positive, coccoid bacteria whose organisms occur in pairs or chains. No endospores are produced. Many species exist as commensals or parasites on man or animals with some being highly pathogenic. A few species are saprophytes and occur in the natural environment.
A genus of bacteriophages of the family MICROVIRIDAE. The genome consists of isometric single-stranded DNA.
Topical antiseptic used mainly in wound dressings.
RNA consisting of two strands as opposed to the more prevalent single-stranded RNA. Most of the double-stranded segments are formed from transcription of DNA by intramolecular base-pairing of inverted complementary sequences separated by a single-stranded loop. Some double-stranded segments of RNA are normal in all organisms.
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
Circular duplex DNA isolated from viruses, bacteria and mitochondria in supercoiled or supertwisted form. This superhelical DNA is endowed with free energy. During transcription, the magnitude of RNA initiation is proportional to the DNA superhelicity.
A commonly used laboratory solvent. It was previously used as an anesthetic, but was banned from use in the U.S. due to its suspected carcinogenicity.
A family of recombinases initially identified in BACTERIA. They catalyze the ATP-driven exchange of DNA strands in GENETIC RECOMBINATION. The product of the reaction consists of a duplex and a displaced single-stranded loop, which has the shape of the letter D and is therefore called a D-loop structure.

Identification of the human melanoma-associated chondroitin sulfate proteoglycan antigen epitope recognized by the antitumor monoclonal antibody 763.74 from a peptide phage library. (1/4361)

To identify the epitope of the melanoma-associated chondroitin sulfate proteoglycan (MCSP) recognized by the monoclonal antibody (mAb) 763.74, we first expressed random DNA fragments obtained from the complete coding sequence of the MCSP core glycoproteins in phages and selected without success for binders to the murine mAb 763.74. We then used a library of random heptapeptides displayed at the surface of the filamentous M13 phage as fusion protein to the NH2-terminal portion of the minor coat protein III. After three rounds of selection on the bound mAb, several phages displaying related binding peptides were identified, yielding the consensus sequence Val-His-Leu-Asn-Tyr-Glu-His. Competitive ELISA experiments showed that this peptide can be specifically prevented from binding to mAb 763.74 by an anti-idiotypic MK2-23 mouse:human chimeric mAb and by A375 melanoma cells expressing the antigen MCSP. We screened the amino acid sequence of the MCSP molecule for a region of homology to the consensus sequence and found that the amino acid sequence Val-His-Ile-Asn-Ala-His spanning positions 289 and 294 has high homology. Synthetic linear peptides corresponding to the consensus sequence as well as to the MCSP-derived epitope inhibit the binding of mAb 763.74 to the phages displaying the consensus amino acid sequence. Finally, the biotinylated consensus peptide absorbed to streptavidin-microtiter plates can be used for the detection of mAb 763.74 in human serum. These results show clearly that the MCSP epitope defined by mAb 763.74 has been identified.  (+info)

Cell-specific peptide binding by human neutrophils. (2/4361)

Analysis of peptide binding to human neutrophils (PMN) using phage display techniques has revealed cell-specific motifs reactive with the PMN surface. Phage libraries displaying either linear 9-mer or cyclic 10-mer and 6-mer peptides were incubated with normal human neutrophils followed by elution of bound phage with low pH (pH 2.2) and non-ionic detergent. Three rounds of selection generated several related peptide sequences that bound with high avidity to PMN. Using the linear 9-mer library, PMN-binding phage expressed peptides with the motif (G/A)PNLTGRW. The binding of phage bearing this motif was highly specific since no binding was observed on lymphocytes, fibroblasts, epithelial, or endothelial cells. Functional assays revealed that phage bearing the sequence FGPNLTGRW induced a pertussis toxin-sensitive increase in PMN cytosolic calcium analogous to that observed with Galphai coupled receptors. Other prominent motifs identified included phage bearing the consensus DLXTSK(M/L)X(V/I/L), where X represents a non-conserved position. Phage with this motif bound exclusively to a sub population of human PMN that comprised approximately 50% of the total and did not elicit a calcium response. The binding of such phage to PMN was prevented by co-incubation with competing peptides displaying identical or similar sequences (IC50 range from 0.6 micromol/L to 50 micromol/L for DLXTSK and GPNLTG, respectively). We speculate that these techniques will be useful in identifying functional cell-specific binding motifs and contribute to the development of new therapeutic and diagnostic strategies in human disease.  (+info)

Synthesis of bacteriophage phi6 double-stranded ribonucleic acid. (3/4361)

Uracil was incorporated into all three bacteriophage phi6 dsRNA segments throughout the infection cycle; the rates of incorporation into each of the three segments were approx. constant for the first 15 to 20 min and then increased rapidly until 50 min after infection. The medium and small dsRNA segments were produced in greater amounts than the large dsRNA segment at all times in the infection cycle. Inhibition of host RNA and protein synthesis with rifampin and chloramphenicol revealed that virus dsRNA synthesis immediately after infection was independent of either host function.  (+info)

Comparison of synonymous codon distribution patterns of bacteriophage and host genomes. (4/4361)

Synonymous codon usage patterns of bacteriophage and host genomes were compared. Two indexes, G + C base composition of a gene (fgc) and fraction of translationally optimal codons of the gene (fop), were used in the comparison. Synonymous codon usage data of all the coding sequences on a genome are represented as a cloud of points in the plane of fop vs. fgc. The Escherichia coli coding sequences appear to exhibit two phases, "rising" and "flat" phases. Genes that are essential for survival and are thought to be native are located in the flat phase, while foreign-type genes from prophages and transposons are found in the rising phase with a slope of nearly unity in the fgc vs. fop plot. Synonymous codon distribution patterns of genes from temperate phages P4, P2, N15 and lambda are similar to the pattern of E. coli rising phase genes. In contrast, genes from the virulent phage T7 or T4, for which a phage-encoded DNA polymerase is identified, fall in a linear curve with a slope of nearly zero in the fop vs. fgc plane. These results may suggest that the G + C contents for T7, T4 and E. coli flat phase genes are subject to the directional mutation pressure and are determined by the DNA polymerase used in the replication. There is significant variation in the fop values of the phage genes, suggesting an adjustment to gene expression level. Similar analyses of codon distribution patterns were carried out for Haemophilus influenzae, Bacillus subtilis, Mycobacterium tuberculosis and their phages with complete genomic sequences available.  (+info)

Analysis of the integration functions of phi304L: an integrase module among corynephages. (5/4361)

Plasmid p12929 was shown to integrate into the chromosome of Corynebacterium glutamicum RM3 and BL15. The minimal integrating fragment was subsequently defined. The arms flanking the integrated plasmid (attL and attR) were identified, allowing for the determination of the attP and the attB attachment sites. The attB site is located at the 3' end of an ORF presenting 62-78% identity with L19 ribosomal proteins. Integration in the attB site does not result in the inactivation of this gene because its end is also present on the attR arm of the integrated plasmid and is reconstituted. The minimal integrating fragment is 1663 bp long and contains two ORFs. The int ORF was identified as phi304L integrase on the basis of the amino acid homologies it shared with the tyrosine recombinases of the lambda integrase family. Moreover this integrase is highly homologous throughout its sequence with the integrase of phi16 corynephage, the percentage of identity reaching 89% at the NH2 end. The identity also extends upstream of the initiation codon, while both phages are elsewhere nonhomologous. An integrase module was proposed to explain this extensive homology.  (+info)

Evolutionary relationships among diverse bacteriophages and prophages: all the world's a phage. (6/4361)

We report DNA and predicted protein sequence similarities, implying homology, among genes of double-stranded DNA (dsDNA) bacteriophages and prophages spanning a broad phylogenetic range of host bacteria. The sequence matches reported here establish genetic connections, not always direct, among the lambdoid phages of Escherichia coli, phage phiC31 of Streptomyces, phages of Mycobacterium, a previously unrecognized cryptic prophage, phiflu, in the Haemophilus influenzae genome, and two small prophage-like elements, phiRv1 and phiRv2, in the genome of Mycobacterium tuberculosis. The results imply that these phage genes, and very possibly all of the dsDNA tailed phages, share common ancestry. We propose a model for the genetic structure and dynamics of the global phage population in which all dsDNA phage genomes are mosaics with access, by horizontal exchange, to a large common genetic pool but in which access to the gene pool is not uniform for all phage.  (+info)

Bacteriophage SPO1 development: defects in a gene 31 mutant. (7/4361)

SPO1 temperature-sensitive mutant ts14-1, located in cistron 31, has a DD (DNA synthesis-delayed) phenotype at 37 degrees C and produces progeny in a stretched program. At 44 degrees C it behaves as a DO (DNA synthesis-defective) mutant and shuts off the viral RNA synthesis about 10 min after infection. The thermal sensitivity of this mutant is due to the inactivity of gp-31 (the product of gene 31) at 44 degrees C. However, gp-31 is synthesized at that temperature and partly recovers its activity at 37 degrees C. Only 5 min at the permissive temperature is enough to trigger the continuation of the phage program and to produce progeny. The partial defect at 37 degrees C and the expansion of the middle program together with the pleiotropic defects at the nonpermissive temperature could be suitable for the study of the controls involved in bacteriophage development.  (+info)

Bacillus subtilis bacteriophages SP82, SPO1, and phie: a comparison of DNAs and of peptides synthesized during infection. (8/4361)

The genomes of Bacillus subtilis phages phie, SPO1, and SP82 were compared by DNA-DNA hybridization, analysis of DNA fragments produced by digestion with restriction endonucleases, comparison of the arrays of peptides synthesized during infection, and phage neutralization. DNA-DNA hybridization experiments indicated that about 78% of the SP82 DNA was homologous with SPO1 DNA, whereas 40% of the phie DNA was homologous to either SPO1 or SP82 DNA. Agarose gel electrophoresis was used to compare the molecular weights of DNA fragments produced by cleavage of SP82, SPO1, and phie DNAs with the restriction endonucleases Hae III, Sal I, Hpa II, and Hha I. Digestion of the DNAs with Hae III and Sal I produced only a few fragments, whereas digestion with Hpa II and Hha I yielded 29 to 40 fragments, depending on the DNA and the enzyme. Comparing the Hpa II fragments, 51% of the SP82 fragments had mobilities which matched those of SPO1 fragments, 32% of the SP82 fragments matched the phie fragments, and 34% of the SPO1 fragments matched the phie fragments. Comparing the Hha I digestion products, 62% of the SP82 fragments had mobilities matching the SPO1 fragments, 24% of the SP82 fragments matched the phie fragments, and 22% of the SPO1 fragments matched the phie fragments. Analysis of peptides by electrophoresis on one-dimensional sodium dodecyl sulfate-polyacrylamide slab gels showed that approximately 70 phage-specific peptides were synthesized in the first 24 min of each infection. With mobility and the intervals of synthesis as criteria, 66% of the different SP82 peptides matched the SPO1 peptides, 34% of the SP82 peptides matched the phie peptides, and 37% of the SPO1 peptides matched the phie peptides. Phage neutralization assays using antiserum to SP82 yielded K values of 510 for SP82, 240 for SPO1, and 120 for phie.  (+info)

Author SummaryCampylobacter jejuni is the major cause of bacterial food-borne illness worldwide. Predation of C. jejuni by virulent bacteriophage offers the prospect of controlling bacterial populations at source in poultry. We report that in chickens, bacteriophage resistance is infrequent because the mutants that escape bacteriophage are not proficient in poultry colonisation but readily revert back to colonisation-proficient phage-sensitive types. Bacteriophage resistance is generated by reversible genomic scale inversions, leading to the activation of an unrelated bacteriophage integrated into the bacterial genome. These data not only suggest that bacteriophage therapy of C. jejuni would remain a sustainable measure to reduce poultry contamination but also demonstrate how bacterial genomes can evolve under the strong and widespread pressure of bacteriophage predation in the environment.
Read TL, the new bacteriophage of Pseudomonas aeruginosa and its application for the search of halo-producing bacteriophages, Russian Journal of Genetics on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
While the harmful effects of lactic acid bacterial bacteriophages in the dairy industry are well-established, the importance of Bacillus subtilis-infecting bacteriophages on soybean fermentation is poorly-studied. In this study, we isolated a B. subtilis-infecting bacteriophage BSP10 from Meju (a brick of dried fermented soybean) and further characterized it. This Myoviridae family bacteriophage exhibited a narrow host range against B. subtilis strains (17/52, 32.7%). The genome of bacteriophage BSP10 is 153,767 bp long with 236 open reading frames and 5 tRNAs. Comparative genomics (using dot plot, progressiveMauve alignment, heat-plot, and BLASTN) and phylogenetic analysis strongly suggest its incorporation as a new species in the Nit1virus genus. Furthermore, bacteriophage BSP10 was efficient in the growth inhibition of B. subtilis ATCC 15245 in liquid culture and in Cheonggukjang (a soybean fermented food) fermentation. Artificial contamination of as low as 102 PFU/g of bacteriophage BSP10 during
Bacteria and their viruses (phages) are abundant across diverse ecosystems and their interactions influence global biogeochemical cycles and incidence of disease. Problematically, both classical and metagenomic methods insufficiently assess the host specificity of phages and phage-host infection dynamics in nature. Here we review emerging methods to study phage-host interaction and infection dynamics with a focus on those that offer resolution at the single-cell level. These methods leverage ever-increasing sequence data to identify virus signals from single-cell amplified genome (SAG) datasets or to produce primers/probes to target particular phage- bacteria pairs (digital PCR and phageFISH), even in complex communities. All three methods enable study of phage infection of uncultured bacteria from environmental samples, while the latter also discriminates between phage-host interaction outcomes (e.g., lytic, chronic, lysogenic) in model systems. Together these techniques enable quantitative,
TY - JOUR. T1 - Antibody response to bacteriophage hyaluronidase in acute glomerulonephritis after group A streptococcal infection. AU - Halperin, Scott A.. AU - Ferrieri, Patricia. AU - Gray, Ernest D.. AU - Kaplan, Edward L.. AU - Wannamaker, Lewis W.. PY - 1987. Y1 - 1987. N2 - In a test of the hypothesis that lysogeny of group A streptococci by a temperate bacteriophage might confer nephritogenicity, 283 sera from 69 patients were examined for IgG and IgM antibodies to M 49 streptococcal bacteriophage hyaluronidase. The IgG and IgM response to bacteriophage hyaluronidase was greatest in M 49 streptococci-infected individuals with nephritis, but M 49 streptococci-infected subjects without nephritis also had a greater immune response than did subjects infected with serotypes other than M 49. Although antibody to bacterial hyaluronidase was detected in all Streptococcus-infected groups, antibody to M 49 streptococcal bacteriophage hyaluronidase usually was found in only M 49 ...
A major limitation with traditional phage preparations is the variability in titer, salts, and bacterial contaminants between successive propagations. Here we introduce the Phage On Tap (PoT) protocol for the quick and efficient preparation of homogenous bacteriophage (phage) stocks. This method produces homogenous, laboratory-scale, high titer (up to 1010-11 PFU·ml−1), endotoxin reduced phage banks that can be used to eliminate the variability between phage propagations and improve the molecular characterizations of phage. The method consists of five major parts, including phage propagation, phage clean up by 0.22 μm filtering and chloroform treatment, phage concentration by ultrafiltration, endotoxin removal, and the preparation and storage of phage banks for continuous laboratory use. From a starting liquid lysate of | 100 mL, the PoT protocol generated a clean, homogenous, laboratory phage bank with a phage recovery efficiency of 85% within just two days. In contrast, the traditional method took
In our country Diarrheal epidemics occur seasonally. Two peaks of outbreaks agreeably coincide with dry season and monsoon rain. Several factors control the outbreaks to occur and collapse. Bacteriophages are one of them which have been reported to trigger the collapse of the outbreaks. The concentration of the Vibrio cholerae specific bacteriophages is inversely correlated with the concentration of Vibrio cholerae in the environment. Therefore bacteriophages probably play an essential role in controlling the epidemics to occur or collapse. It is still not clear what factors trigger the onset of Diarrheal outbreaks. This study was design to see the effect of E. coli bacteriophages on the epidemics of Diarrheal disease. Routine isolation, estimation and molecular characterization reveal the prevalence E. coli phage. We have tried to characterize the isolated phages by analyzing the DNA using the technique called restriction fragments length polymorphism (RFLP ...
The detection and quantification of enteric RNA viruses is based on isolation of viral RNA from the sample followed by quantitative reverse transcription polymerase chain reaction (RT-qPCR). To control the whole process of analysis and in order to guarantee the validity and reliability of results, process control viruses (PCV) are used. The present article describes the process of preparation and use of such PCV- MS2 phage-like particles (MS2 PLP) - in RT-qPCR detection and quantification of enteric RNA viruses. The MS2 PLP were derived from bacteriophage MS2 carrying a unique and specific de novo-constructed RNA target sequence originating from the DNA of two extinct species. The amount of prepared MS2 particles was quantified using four independent methods - UV spectrophotometry, fluorimetry, transmission electron microscopy (TEM) and a specifically developed duplex RT-qPCR. To evaluate the usefulness of MS2 PLP in routine diagnostics different matrices known to harbor enteric RNA viruses (swab
Bacteriophages escaping from a dying bacterial cell (Streptococcus sp.), coloured scanning electron micrograph (SEM). This bacteriophage was discovered in freshwater near a sewage outlet. A bacteriophage, also known as a phage, is a virus (virion) that infects a bacterium. It consists of a head (capsid), containing the genetic material (either RNA or DNA) and usually a tail and tail fibres (not seen), which the phage uses to attach to a specific receptor sites on the bacterium. This specific binding means that a bacteriophage can only infect certain bacteria bearing specific receptors. Once attached to the cell surface genetic material is injected into the bacterium, taking over the bacteriums own cellular machinery and forcing it to produce more copies of the bacteriophage. When sufficient numbers have been produced the phages escape from the bacterium by cellular lysis, killing the bacterium in the process. Magnification: x21,335 when shortest - Stock Image C032/0258
Food treated with bacteriophage, as to reduce or prevent the growth of undesirable bacteria. The food treated comprises: a food product; a first, fatty or waxy coating layer on the food product; and a second coating layer comprising one or more bacteriophage strains, wherein the fatty or waxy coating layer is distinct from the coating layer comprising the one or more bacteriophage strains. The food may be coated with bacteriophage and rubbed to distribute the phage on the food surface. The food may be preferably a pet food. The food may be coated in two or more layers. A process for treating food with bacteriophage comprises contacting the food with the bacteriophage and rubbing the coated food surface. The coating and/or rubbing may be performed in vibratory conveyor.
Gómez P., Bennie J., Gaston K.J. & Buckling A. (2015) The Impact of Resource Availability on Bacterial Resistance to Phages in Soil. PLoS ONE 10(4): e0123752.. Resource availability can affect the coevolutionary dynamics between host and parasites, shaping communities and hence ecosystem function. A key finding from theoretical and in vitro studies is that host resistance evolves to greater levels with increased resources, but the relevance to natural communities is less clear. We took two complementary approaches to investigate the effect of resource availability on the evolution of bacterial resistance to phages in soil. First, we measured the resistance and infectivity of natural communities of soil bacteria and phage in the presence and absence of nutrient-providing plants. Second, we followed the real-time coevolution between defined bacteria and phage populations with resource availability manipulated by the addition or not of an artificial plant root exudate. Increased resource ...
This chapter focuses on the doublestranded DNA (dsDNA) phages, and especially on the temperate phages. While virulent phages certainly perform transduction and engage in evolutionary sparring with their hosts and so influence their evolution, the chapter focuses mainly on the complex interactions of temperate phages with their hosts. Bacteriophages may thus have contributed to the current compact nature of bacterial genomes. The approximately 100 currently published bacterial genome complete nucleotide sequences, and about 285 prophages are related to known bacteriophages. Of the more than 280 prophages in the currently sequenced bacterial genomes, only a few are known to be fully functional bacteriophages. There are two rather complex types of genetic entity in which this appears to have happened: the phage tail-like bacteriocins and the gene transfer agents. To date, protection from other phages and disease virulence factors are the lysogenic conversion genes that have been discovered and studied in
The Pseudomonas genus is a big problem mainly for the poultry food industry. The shelf life of chicken carcasses stored under refrigeration is limited by the appearance of undesirable odors and sliminess surface generated primarily by Gram negative bacteria. Due to the subsequent emergence of resistant bacteria, is necessary proving new alternatives as guaranty the microbiological quality of foods and human health. Bacteriophages or phages are viruses of bacteria that use resources of bacteria for their replication and killing bacteria naturally, showing them as a potential tool for bacteria biocontrol in food industry. In this study, 11 bacteriophages were isolated from the exudate product of defrost of chicken carcasses using as host strains Pseudomonas aeruginosa (ATCC 25619) and Pseudomonas fluorescens (ATCC 13525). This study also aimed at the purification, quantification and morphological and molecular characterization of phages (RFLP). Bacteriophage can be found in all types of ...
Since 2006, the United States Food and Drug Administration (FDA) and United States Department of Agriculture (USDA) have approved several bacteriophage products. LMP-102 (Intralytix) was approved for treating ready-to-eat (RTE) poultry and meat products. In that same year, the FDA approved LISTEX (developed and produced by Micreos) using bacteriophages on cheese to kill Listeria monocytogenes bacteria, giving them generally recognized as safe (GRAS) status.[23] In July 2007, the same bacteriophage were approved for use on all food products.[24] In 2011 USDA confirmed that LISTEX is a clean label processing-aid and is included in USDA.[25] Research in the field of food safety is continuing to see if lytic phages are a viable option to control other food-borne pathogens in various food products. In 2011 the FDA cleared the first bacteriophage-based product for in vitro diagnostic use.[26] The KeyPath MRSA/MSSA Blood Culture Test uses a cocktail of bacteriophage to detect Staphylococcus aureus in ...
In the article, Dr Mohammed and Dr Millard discuss the issue of antibiotic resistance and warned that we are on the cusp of a post-antibiotic era. They outlined how viruses that infect and kill bacteria, known as bacteriophages (phages), may be a possible alternative to antibiotics. They wrote: Bacteriophages can survive in many environments, including deep sea trenches and the human gut. While phages are efficient killers of bacteria, they dont infect human cells and are harmless to humans.. They added: Lytic bacteriophages are preferred for treatment because they dont integrate into the bacterial hosts chromosome. But it is not always possible to develop lytic bacteriophages that can be used against all types of bacteria.. Dr Mohammed and Dr Millard indicated that for bacteriophages to become commonplace for curing infections, there needs to be more research into the area of how bacteriophages interact with bacteria.. Read the full article on The Conversations website.. ...
Bacteriophages are viruses that attack bacteria--their name means bacteria eater in Latin. Here, you can see a bunch of bacteriophages on the surface of a bacterial cell. They look sort of like balloons tethered to the surface of the moon. They were discovered near the dawn of the twentieth century, and at first they enjoyed…
Bacteriophage T4 viruses. 3D computer illustration of multiple T4 bacteriophage viruses. A bacteriophage, or phage, is a virus that infects bacteria. Enterobacteria T4 infects E. coli bacteria. It consists of an icosahedral (20-sided) head, which contains the genetic material, a tail (cylindrical) and tail fibres (leg-like). The tail fibres attach to the surface of the bacterium and the tail injects a DNA (deoxyribonucleic acid) strand into the cell. The viral genetic material then hijacks the bacteriums own cellular machinery, forcing it to produce more copies of the bacteriophage. When a sufficient number have been produced, the phages burst out of the cell, killing it in the process. - Stock Image C024/7526
Sigma-Aldrich offers abstracts and full-text articles by [Thomas Denes, Henk C den Bakker, Jeffrey I Tokman, Claudia Guldimann, Martin Wiedmann].
Given a recent increase in the number of bacteriophage genome sequenced- Nathan ( @NathanMB3) has updated the all-v-all comparison with more genomes (~5500 in total).Image at bottom of page. After reading the recent paper MASH:fast genome and metagenome distance and estimation using MinHash and meeting Nathan Brown at the University of Leicester, we discussed using MASH for identification of phage genomes and comparison thereof. The authors of the genome biology paper had included viruses in the microbial comparison in Figure 3 . Here we just focused on bacteriophage genomes.. For rapid identification of phage genomes we first constructed a database of phage genomes that were public. This included all phage genomes from the NCBI ( , which were then filtered to remove eukaryotic viruses. In addition phage genomes were collected from the website. A sketch was made for all of these phages and collated, the mash database of ...
Phage transduction is used to move selectable genetic markers from one donor strain to another recipient strain. Nat Sternberg, among others, pioneered the use of phage P1 to move genetic elements in E. coli and the use of the Cre/Lox system from P1 for controlled recombination. Today, phage P1 is commonly used as a transducing agent because it is a generalized tranducer (it can package random sections of the host chromosome instead of its own genome) giving rise to transducing particles. P1vir is a mutant phage that enters the lytic cycle upon infection (ensuring replication and lysis). During the replication and lysis of the phage in a culture of bacteria, a small percentage of the phage particles will contain a genome segment that contains your gene of interest. P1 packages approximately 90 kb of DNA, so you can transduce genes that are linked to a selectable marker. Once a phage population has been generated from a donor host, the phage are used to infect a recipient host. Most of the ...
Hi all, I am looking for a way or a tool to map all the GC rich (of given percentage say, 60% or 70% GC) short stretches of nucleotides anywhere between 20-80 base pairs in Bacteriophage T4 and other Phage genomes.I could not find such a tool at NCBI website. I highly appreciate your help. Thank you so much Kiran ...
Bacteriophages (phages) are obligate intracellular parasites of bacteria. The basic life cycle of phages involves the use of bacterial cellular metabolism for production of new phage particles, release of those particles from their cellular confines, and then infection of new host cells (1). Phage infection is initiated by the phage binding to a specific receptor on the surface of the host bacterium, followed by the delivery of the phage genome to the host cell. Adsorption involves multiple steps, including reversible binding for the initial recognition and proper positioning, followed by irreversible binding to the final receptor. However, the molecular mechanisms by which phages deliver their genomes into a host are far from being elucidated.. Generally, a phage is able to infect a limited number of bacterial strains or related strains of the same species (2, 3). Interactions between a phage and the host bacteria is primarily dependent on the nature and structural characteristics of receptors ...
View Notes - phage normally infects cells to make more phage from BIOLOGY MCB2010 at Broward College. P PP P : Infect bacteria with ~10 of each phage per cell to insure that every cell has both kinds
Prospective Interdisciplinary PhD Projects. Tackling antibiotic resistance by measuring and modelling the uptake of viruses and antibiotics in single cell (co-supervised with Prof Krasimira Tsaneva-Atanasova). This interdisciplinary project will provide novel understanding on the biological mechanisms underlying antibiotic and phage uptake in gram-negative bacteria which is paramount for our battle against infectious diseases. In this project we aim to quantitate the accumulation of antibiotics and bacteriophage in gram negative species such as Escherichia coli and Pseudomonas aeruginosa, combining fluorescent drug derivatives, stained phage and single-bacterium imaging. These data will be rationalised by using a mathematical model that describes the temporal changes in antibiotic or phage concentration in single bacteria and will inform how phenotypic heterogeneity, in both the bacterial and phage populations, impacts on population and evolutionary dynamics. Taken together the information ...
1307 patients with suppurative bacterial infections caused by multidrug resistant bacteria of different species were treated with specific bacteriophages (BP). BP therapy was highly effective; full recovery was noted in 1123 cases (85.9%). In 134 cases (10.9%) transient improvement was observed and only in 50 cases (3.8%) BP treatment was found to be ineffective. The results confirm the high effectiveness of BP therapy in combating bacterial infections which do not respond to treatment with all available antibiotics ...
Bacteriophage is a live micro-organism, a natural enemy of bacteria. Canadian microbiologist Felix d Herelle proposed that bacteriophage might be applied to the control of bacterial diseases, however in the West this idea was not explored with the same enthusiasm as in the former Soviet Union and was eventually discarded with the arrival of antibiotics. Phage therapy is successfully used for the treatment of a wide spectrum of bacterial infections. Such experience has now become extremely important with the rapidly-increasing spread of antibiotic-resistant bacterial infections which are almost impossible to overcome these days. Phage therapy has been considered as an alternative to antibiotic-therapy and it is now attracting global interest. Most of the scientific works in phage therapy were published in Russian and are thus not easily available in the West. This fact inspired the authors to write a book based on the historical publications found in the library of the Eliava Institute. (Imprint: ...
Increasing resistance to antibiotics and market demands for clean label processes has led to increased focus on new strategies to control pathogenic bacteria in foods and animal production. Bacteriophages are among the top predators of bacteria in nature - ubiquitous in the environment yet also highly specific - making them attractive as antimicrobials. This webinar will cover some of the basic biology of phages, how they work and some considerations on initial product development.. Presenter:. Dr. Jason Gill joined the faculty of the Department of Animal Science as an Assistant Professor in 2013. Dr. Gills major research focus is the biology and application of the viruses of bacteria, called bacteriophages or simply phages. As natural predators of bacteria, phages are attractive agents for the control of pathogenic bacteria in humans, animals, and foods. Research in Dr. Gills lab encompasses phage genomics, basic phage biology and the applications of phages in real-world settings against ...
View DNA Rearrangements from BIOLOGY MCB2010 at Broward College. Examples : Integration of bacteriophage DNA into host bacterial chromosome Immunoglobulin and T Cell Receptor genes DNA rearrangements
TY - JOUR. T1 - Efficient in vitro synthesis of biologically active RNA and RNA hybridization probes from plasmids containing a bacteriophage SP6 promoter. AU - Melton, D. A.. AU - Krieg, P. A.. AU - Rebagliati, M. R.. AU - Maniatis, T.. AU - Zinn, K.. AU - Green, M. R.. N1 - Funding Information: ACKNOWLEDGEMENTS We are grateful to D. Ward and B. Mierendorf for sharing their unpublished results. We thank K. Breakey for help in preparing figures. P. K. acknowledges support from the Fogarty International Fellowship program. M.R. is grateful for support from an NSF Predoctoral Fellowship. This work was supported by a grant from the NIH to T.M. and grants from the NIH and the Chicago Community Trust/Searle Scholars Program to D.M. Copyright: Copyright 2010 Elsevier B.V., All rights reserved.. PY - 1984/9/25. Y1 - 1984/9/25. N2 - A simple and efficient method for synthesizing pure single stranded RNAs of virtually any structure is described. This in vitro transcription system is based on the ...
Middleton C.A., J.L. Pate. 1976. Isolation and partial characterization of some new bacteriophages active against Asticcacaulis strains. Int. J. Syst. Bacteriol. 26: 269-277. ...
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The number of successful propagations/isolations of soil-borne bacteriophages is small in comparison to the number of bacteriophages observed by microscopy (great plaque count anomaly). As one...
Most human microbiota studies focus on bacteria inhabiting body surfaces, but these surfaces also are home to large populations of viruses. Many are bacteriophages, and their role in driving bacterial diversity is difficult to decipher without the use of in vitro ecosystems that can reproduce human microbial communities. We used chemostat culture systems known to harbor diverse fecal bacteria to decipher whether these cultures also are home to phage communities. We found that there are vast viral communities inhabiting these ecosystems, with estimated concentrations similar to those found in human feces. The viral communities are composed entirely of bacteriophages and likely contain both temperate and lytic phages based on their similarities to other known phages. We examined the cultured phage communities at five separate time points over 24 days and found that they were highly individual-specific, suggesting that much of the subject-specificity found in human viromes also is captured by this culture
The world is in the midst of a global superbug crisis. Antibiotic resistance has been found in numerous common bacterial infections, including tuberculosis, gonorrhoea and salmonellosis, making them difficult - if not impossible - to treat. Were on the cusp of a post-antibiotic era, where there are fewer treatment options for such antibiotic-resistant strains. Given estimates that antibiotic resistance will cause 10 million deaths a year by 2050, finding new methods for treating harmful infections is essential.. Strange as it might sound, viruses might be one possible alternative to antibiotics for treating bacterial infections. Bacteriophages (also known as phages) are viruses that infect bacteria.. Theyre estimated to be the most abundant organisms on Earth, with probably more than 1031 bacteriophages on the planet. They can survive in many environments, including deep sea trenches and the human gut. While phages are efficient killers of bacteria, they dont infect human cells and are ...
For whoever is qualified to answer me: I would like to know what specific Bacteriophages will attack Salmonella enteriditis. I am working on the potential antibacterial affects of phages against human pathogens. Any responses will be greately appreciated Thank you George T ...
Sabella has two different morphologies: some of the plaques are 0.1 cm in diameter, while others are 0.15 cm in diameter. This notable difference was tested multiple times, so the phage population of this lytic phage is consistent and contains two morphologies. All the plaques are clear and round with smooth edges ...
- SS2378646 A bacteriophage, comprising a proteic envelope (called capsid), which contains its nucleic acid (DNA or RNA), and a tail. The tail includes a collar (covered with contractile proteins for the most elaborated bacteriophages, such as the T2 and T4 phages) and ending with tail fibers enabling it to attach to the bacteria it infects.
A type of single-stranded DNA bacteriophage ( virus which infects bacteria ) that has a capsid which is long and thin, like a filament. Examples include the viruses F1 and M13 ... Bacteriophage, viruses that specifically infect bacteria, are, by far, the majority of all biological entities in the biosphere....
There are many similarities in the replication mechanisms employed by bacteriophage λ and its host E. coli(for reviews, see Bramhill and Kornberg, 1988, Keppel et al., 1988, and McMacken et al.,...
While I can find a wealth of information on the theory of bacteriophages, I cant seem to find anything useful on their actual use(though I hear theyre used with frequency in Georgia[the country]). Ever since Ive known what they are, Ive thought that bacteriophages would be perfect to treat acne. When I saw this article, I was slightly hopeful that I might find a clinical trial(at, but I found exactly bupkis ...
While I can find a wealth of information on the theory of bacteriophages, I cant seem to find anything useful on their actual use(though I hear theyre used with frequency in Georgia[the country]). Ever since Ive known what they are, Ive thought that bacteriophages would be perfect to treat acne. When I saw this article, I was slightly hopeful that I might find a clinical trial(at, but I found exactly bupkis ...
Help your students understand the connection between bacteriophages and human disease. This scholarly overview explores how bacteriophages have helped and hindered humans in their quest to overcome certain diseases. Use it as assigned reading or to kick off a classroom discussion.
This sequence contains a string of Gs starting at 32032 bp, consensus determined to contain 13 Gs. Some of the phage population may contain anywhere from 8-14 Gs at this location ...
Viruses are parasitic infectious agents with a nanoscale shell, known as the capsid, that encapsulates the genomic material. Most bacteriophage viruses invade bacteria by transferring their genome inside the host cell while leaving the capsid outside. Thus, the foremost event of bacteriophage infection is the ejection of genomic material into the host bacterium after the virus has recognized and bound to surface receptor sites. How ejection is triggered is yet unknown. We show, by manipulating individual mature T7 phage particles, that tapping the capsid wall with an oscillating atomic-force-microscope cantilever triggers rapid DNA ejection via the tail complex. Triggering rate increases exponentially as a function of force, hence follows transition-state theory, across an activation barrier of 23 kcal/mol at 1.2 nm along the reaction coordinate. The conformation of the ejected DNA molecule revealed that it had been exposed to a propulsive force. This force, arising from intra-capsid pressure, assists
Generalized transduction is commonly used to move transposon-induced mutations among bacterial strains by selecting for inheritance of a transposonencoded resistance determinant. Although complete cotransduction of the resistance determinant and the chromosomal mutation might be expected, it is often found that when Tn5(Kan) insertion mutations are transduced by bacteriophage P1 most of the nonmutant kanamycin-resistant transductants are due to specialized transduction of Tn5. Such P1::Tn5 specialized transducing phage are not found when a mutant Tn5 element lacking a functional transposase is employed.. ...
Froman, S., W. Drake, E. Bogen. 1954. Bacteriophage active against virulent Mycobacterium tuberculosis. I. Isolation and activity. Amer. J. Publ. Health. 44: 1326-1333. ...
Answer. Viruses are sub6microscopic infectious agents that can infect all living organisms. A virus consists of genetic material surrounded by a protein coat. The genetic material may be present in the form of DNA or RNA.. Most of the viruses, infecting plants, have single stranded RNA as genetic material. On the other hand, the viruses infecting animals have single or double stranded RNA or double stranded DNA. Bacteriophages or viruses infecting bacteria mostly have double stranded DNA. Their protein coat called capsid is made up of capsomere subunits. These capsomeres are arranged in helical or polyhedral geometric forms. ...
The prevalence of pathogenic bacteria acquiring multidrug antibiotic resistance is a global health threat to mankind. This has motivated a renewed interest in developing alternatives to conventional antibiotics including bacteriophages (viruses) as therapeutic agents. The bacterium Clostridium difficile causes colon infection and is particularly difficult to treat with existing antibiotics; phage therapy may offer a viable alternative. The punitive environment within the gastrointestinal tract can inactivate orally delivered phages. C. difficile specific bacteriophage, myovirus CDKM9 was encapsulated in a pH responsive polymer (Eudragit® S100 with and without alginate) using a flow focussing glass microcapillary device. Highly monodispersed core-shell microparticles containing phages trapped within the particle core were produced by in situ polymer curing using 4-aminobenzoic acid dissolved in the oil phase. The size of the generated microparticles could be precisely controlled in the range 80 ...
Phage therapy or viral phage therapy is the therapeutic use of bacteriophages to treat pathogenic bacterial infections. Phage therapy has many potential applications in human medicine as well as dentistry, veterinary science, and agriculture. If the target host of a phage therapy treatment is not an animal, the term biocontrol (as in phage-mediated biocontrol of bacteria) is usually employed, rather than phage therapy. Bacteriophages are much more specific than antibiotics. They are typically harmless not only to the host organism, but also to other beneficial bacteria, such as the gut flora, reducing the chances of opportunistic infections. They have a high therapeutic index, that is, phage therapy would be expected to give rise to few side effects. Because phages replicate in vivo, a smaller effective dose can be used. On the other hand, this specificity is also a disadvantage: a phage will only kill a bacterium if it is a match to the specific strain. Consequently, phage mixtures are ...
An efficient heat-inducible Bacillus subtilis bacteriophage 105 expression and secretion system for the production of the Streptomyces clavuligerus beta-lactama
Bacteriophages, the viruses that infect bacteria, are the most abundant biological entities in the biosphere and play a key role in global biogeochemical cycling. All T4-type bacteriophage isolates tested so far have a conserved genetic module that encodes the virion components including gene 23 (g23), the major capsid protein. Molecular analysis of the g23 sequence revealed a remarkable level of diversity of T4-type bacteriophages isolated from rice straw and surface soil in a Japanese rice field. It was found that g23 sequences obtained from the rice field were quite distinctive from those obtained in marine environments. Phylogenetic analysis showed that most of these g23 sequences belonged to two novel subgroups of T4-type bacteriophages, although some of them were related to well-studied subgroups of T4-type bacteriophages, such as marine cyanophage isolates of exoT-evens. ...
Urinary tract infections (UTIs) are among the most prevalent microbial diseases and their financial burden on society is substantial. In the context of increasing antibiotic resistance, finding alternative treatments for UTIs is a top priority. We aimed to determine whether intravesical bacteriophage therapy with a commercial bacteriophage cocktail is effective in treating UTI.. Intravesical bacteriophage therapy was non-inferior to standard-of-care antibiotic treatment, but was not superior to placebo bladder irrigation, in terms of efficacy or safety in treating UTIs in patients undergoing TURP. Moreover, the bacteriophage safety profile seems to be favourable. Although bacteriophages are not yet a recognised or approved treatment option for UTIs, this trial provides new insight to optimise the design of further large-scale clinical studies to define the role of bacteriophages in UTI treatment.. ...
TY - JOUR. T1 - Size exclusion-based purification and PCR-based quantitation of MS2 bacteriophage particles for environmental applications. AU - Farkas, Kata. AU - Varsani, Arvind. AU - Marjoshi, Delphine. AU - Easingwood, Richard. AU - McGill, Erin. AU - Pang, Liping. N1 - Funding Information: This work was funded by the Royal Society of New Zealand (Marsden Grant ESR-1001 ). D. Marjoshi was supported by a summer scholarship provided by the Royal Society of New Zealand and the University of Canterbury, New Zealand. The authors thank the following people for their support and assistance: R. Fredericks (University of Canterbury, New Zealand), W. Williamson and M. Mackenzie (Institute of Environmental Science & Research Ltd, New Zealand). PY - 2015/3/1. Y1 - 2015/3/1. N2 - MS2 bacteriophage is the most commonly used surrogate for pathogenic viruses in laboratory and field studies. In order to determine the number of infectious viral particles in samples, the use of accurate quantitation methods is ...
Summary Tris(hydroxymethyl)aminomethane (tris) inactivates Lactobacillus lactis bacteriophage LL-H in vitro. The inactivation is caused by DNA ejection. This effect occurs in tris-HCl buffer only. Both pH and temperature affect the sensitivity of the phage to the tris treatment. The divalent cation Mg2+ prevented the inactivating effect of tris at concentrations about 103-fold lower than for the monovalent cation K+.
Abstract: Bacteriophages have been proposed as specific alternative for chemotherapy against multidrug resistant bacterial infections. The aim of the present study was the isolation and purification of bacteriophages from sewage, which were effective against multidrug resistant bacterial isolates and detection of their morphological characteristics. Sewage and clinical samples were used for the isolation of antibiotic resistant pathogenic bacteria. The bacteriophages were isolated and purified from sewage samples by overlay cultures of the isolated bacteria after centrifugation and filtration procedures. Three isolates of the most multidrug resistant Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa selected for bacteriophage isolation. Most of the isolates were resistant to different classes of antibiotics in the aminoglycosides, cephalosporins, macrolides, tetracyclines and β-lactam antibiotic groups. The isolated bacteriophges showed different plaque morphologies on the ...
The bacteriophage MS2 is an icosahedral, positive-sense single-stranded RNA virus that infects the bacterium Escherichia coli and other members of the Enterobacteriaceae. MS2 is a member of a family of closely related bacterial viruses that includes bacteriophage f2, bacteriophage Qβ, R17, and GA. In 1961, MS2 was isolated by Alvin John Clark and recognized as an RNA-containing phage very similar to bacteriophage f2. In 1976, the MS2 genome was the first genome to be completely sequenced. This was accomplished by Walter Fiers and his team, building upon their earlier milestone in 1972 of the first gene to be completely sequenced, the MS2 coat protein. These sequences were determined at the RNA level, whereas the next landmark achievement, the sequence of the bacteriophage ΦX174 genome in 1977, was determined using DNA. The first effort at a statistical analysis of the MS2 genome was a search for patterns in the nucleotide sequence. Several non-coding sequences were identified, however at the ...
The aim of this work was to verify the possibility of applying affinity chromatography in bacteriophage purification, from the perspective of therapeutic purposes. Elution profiles of phages modified with specific affinity motifs (Figures 3,4,5 and 6) show substantially higher phage concentration in elution fractions compared to final washing samples. This indicates binding of modified phages to the affinity resins and effective elution with standard competitive agents. Thus, affinity tags can be successfully incorporated into the T4 phage capsid by the in vivo phage display technique and they strongly elevate bacteriophage affinity to a specific resin. Non-specific binding was also observed: unmodified phages or those modified with the non-specific tag were eluted with the titre 104-105 pfu/ml. Nevertheless, the unspecific binding is 102-105 times weaker than the specific one and importantly it does not interfere with the aim of preparation of purified anti-bacterial active bacteriophages for ...
Phage therapy has also proven to be an effective therapeutic tool in fighting pathogenic strains of Escherichia coli, particularly in preventing the development of colibacillosis, which initially develops in the respiratory tract and air sacs and then takes the form of sepsis, causing considerable mortality in poultry.. Phage suspensions applied directly to the air sac in 3-day-old birds in a range of titres from 106 to 103 PFU to treat E. coli infections substantially reduced mortality rates to 5% and 25%, respectively. Similar results were obtained after inoculation of a bacteriophage suspension in the drinking water of birds at 1 week of age (103 or 104 PFU of bacteriophages per mL) followed by air sac challenge with 103 CFU of E. coli phages. Mortality was decreased to 25% and 5%, respectively. No mortality was observed in chickens treated with 108 PFU of an E. coli bacteriophage mixture [38]. Bacteriophages have also been shown to be highly effective in treating sepsis and meningitis in ...
Bacterial urinary tract infections (UTIs) are very frequent, especially in patients with neurogenic lower urinary tract dysfunction (NLUTD). The steady increase in antibiotic resistance among causative bacteria prompts the search for highly effective therapeutic alternatives with little or no side effects. Bacteriophages - obligate intracellular viruses that solely infect and kill bacteria - are promising tools for treating bacterial infections and have been used for this purpose for almost a century. Recent clinical studies using bacteriophage therapy for UTIs showed encouraging results. In particular, patients with recurrent UTIs, such as individuals with NLUTD who rely on assisted bladder emptying, might benefit from this treatment method. However, bacteriophages are not yet a panacea. More high-quality basic and clinical research on bacteriophage therapy is needed to answer questions on the use of this therapeutic option and its potential to provide a solution to the global threat of ...
TY - PAT. T1 - SELECTION SYSTEM FOR PHAGEMIDS USING PROTEOLYTICALLY SENSITIVE HELPER PHAGE. AU - Lutz, Riechmann. AU - Peter, Kristensen. AU - Jean-Luc, Jestin. AU - Gregory Paul, Winter. AU - Lutz , Riechmann. AU - Peter , Kristensen. AU - Jean-Luc , Jestin. AU - Gregory Paul , Winter. PY - 2003/3/26. Y1 - 2003/3/26. N2 - A method for effecting helper phage rescue of a phagemid comprising a fusion polypeptide to form progeny bacteriophage wherein (a) the helper phage encodes a viral coat protein comprising a protease sensitive cleavage site (b) the phagemid comprises a fusion polypeptide (c) the progeny phage are exposed to a protease capable of cleaving the proteolytically cleavable site such that the cleavage of the protein derived from the helper phage impairs its ability to mediate infection and (d) the progeny are propagated by infection. The helper phage has the protease sensitive site within p3 coat protein and is the filamentous bacteriophage M13, fd or a related species.. AB - A method ...
Regular use of phage therapy occurs primarily in the Republic of Georgia, due to the presence of the Eliava Institute, which has research phage therapy since the 1920s. However, synthetic biology has enabled entirely new approaches to phage therapy, such as engineering new abilities into the phage. One such ability is the degradation of the extracellular polysaccharides (EPS) produced by bacteria during infections[2]. Production of the EPS results in a biofilm, which protects the bacteria within from external harm, such as antibiotics and bacteriophages, limiting the damage to the cells on the surface. To break through this barrier, researches inserted the gene for DspB, an enzyme that degrades one of the key components of EPS. After bacteria on the surface of the biofilm are infected, they produce DspB along with new phage. After the cells lyse, the DspB can degrade the EPS, which exposes more bacteria to infection. One concern of phage therapy is the rapid lysing of pathogenic cells which may ...
Bacteriophages are an important repository of genetic diversity. As one of the major constituents of terrestrial biomass, they exert profound effects on the earths ecology and microbial evolution by mediating horizontal gene transfer between bacteria and controlling their growth. Only limited genomic sequence data are currently available for phages but even this reveals an overwhelming diversity in their gene sequences and genomes. The contribution of the T4-like phages to this overall phage diversity is difficult to assess, since only a few examples of complete genome sequence exist for these phages. Our analysis of five T4-like genomes represents half of the known T4-like genomes in GenBank. Here, we have examined in detail the genetic diversity of the genomes of five relatives of bacteriophage T4: the Escherichia coli phages RB43, RB49 and RB69, the Aeromonas salmonicida phage 44RR2.8t (or 44RR) and the Aeromonas hydrophila phage Aeh1. Our data define a core set of conserved genes common to these
0036] Disclosed methods may be utilized to simultaneously detect a plurality of different pathogens. For instance, a plurality of recombinant bacteriophages specific for different bacterial pathogens may be located at a potential infection site or in an in vitro environment in which the pathogenic bacteria may exist. The recombinant bacteriophages may be engineered to encode for the same detectable markers or for different detectable markers, as desired. For instance, a plurality of different phages may all encode the same detectable marker. Upon detection of the marker, a medical professional may be alerted to the presence of a pathogen at the site of interest, signaling the need for further investigation to determine the specific bacteria involved. In another embodiment, different phages may encode different markers. According to this embodiment, determination of the characteristics of a detected signal may provide information regarding the specific bacteria involved in the infection. ...
Usually bacteriophages lyse their hosts following infection, however a few so-called temperate phage undergo lysogeny. In lysogeny, the bacteriophage integrates its genome into that of its host. The phage, then, is replicated each time the bacterial cell divides. In the lysogenic state, the bacteriophage can have considerable influence over host physiology ...
In the United States, billions of pounds of animal by-products are generated by the food processing industry every year. Hydrogen sulfide producing bacteria (SPB) can utilize the sulfur-containing proteins and amino acids in the raw animal materials destined for the rendering process to produce harmful hydrogen sulfide (H2S) gas rapidly under the ambient conditions, resulting in hazardous working environments and inferior quality of finished products. In this study, the application of bacteriophage was explored as an effective solution for the elimination of H2S production in the rendering industry. The objectives of this study were to: 1) isolate and characterize strains of SPB and their specific bacteriophages, 2) to develop and optimize a bacteriophage cocktail specific for SPB, 3) to reduce the SPB population and H2S production in raw animal materials by administering phage cocktail under both laboratory condition and greenhouse environment. Twenty two meat, chicken offal and feather samples
0040]Purification of the bacteriophages can be obtained by known methods. As an example, the culture medium can be filtered through a very small pore size filter to retain the targeted contaminant--i.e., the bacteria--, and permit the smaller bacteriophage to pass through. Typically, a filter having a pore size in the range of from about 0.01 to about 1 μm can be used, preferably from about 0.1 to about 0.5 μm, and more preferably from about 0.2 to about 0.4 μm. The culture medium can be also purified from bacterial debris and endotoxins by dialysis using the largest pore membrane that retains bacteriophages, where the membrane preferably has a molecular cut-off of approximately 104 to about 107 daltons, preferably within the range of from about 105 to about 106 daltons. Many other suitable methods can be performed as disclosed for example in US 2001/0026795; US 2002/0001590; U.S. Pat. No. 6,121,036; U.S. Pat. No. 6,399,097; U.S. Pat. No. 6,406,692; U.S. Pat. No. 6,423,299; and WO 02/07742, ...
Bacteria and archaea have evolved an adaptive, heritable immune system that recognizes and protects against viruses or plasmids. This system, known as the CRISPR/Cas system, allows the host to recognize and incorporate short foreign DNA or RNA sequences, called spacers into its CRISPR system. Spacers in the CRISPR system provide a record of the history of bacteria and phage coevolution. We use a physical model to study the dynamics of this coevolution as it evolves stochastically over time. We focus on the impact of mutation and recombination on the evolution and evasion of bacteria and phages. We discuss the effect of different spacer deletion mechanisms on the coevolutionary dynamics. We make predictions about bacteria and phage population growth, spacer diversity within the CRISPR locus, and spacer protection against the phage population. An important feature of this coevolution is the multiple loci in the phages from which CRISPR may sample genetic material. We construct a model with ...
Summary Three newly isolated strains of Streptomyces phages have been examined by electron microscopy using the negative-staining technique. These phages have polyhedral heads and noncontractile tails ending in a clearly distinct fixation structure. They differ in their dimensions, head outline, flexibility of the tail and type of fixation plate. Some of their characteristics are new in the group of actinophages but correspond to known structures in other phage groups.
Knowledge of phage-host interactions at a fundamental level is central to the design of rational strategies for the development of phage-resistant strains that may be applied in industrial settings. Phages infecting lactic acid bacteria, in particular Lactococcus lactis and Streptococcus thermophilus, negatively impact on dairy fermentation processes with serious economic implications. In recent years a wealth of information on structural protein assembly and topology has become available relating to phages infecting Escherichia coli, Bacillus subtilis and Lactococcus lactis, which act as models for structural analyses of dairy phages. In this review, we explore the role of model tailed phages, such as T4 and SPP1, in advancing our knowledge regarding interactions between dairy phages and their hosts. Furthermore, the potential of currently investigated dairy phages to in turn serve as model systems for this particular group of phages is discussed.
Since the advent of antibiotics, both the health care and agriculture sectors have relied heavily on them to control bacterial pathogens. However, increasing levels of antibiotic resistance have reduced the efficacy of many current therapies, prompting legislation that has reduced the use of antibiotics in animals. This has led researchers to seek fresh ideas. Bacteriophage therapy is one old idea undergoing a renaissance, with the potential to resolve the antibiotic predicament we find ourselves in today. Lytic bacteriophages are viruses that attach to specific bacterial surface receptors, inject their DNA, and express genes that lead to the synthesis of new phages. The process ends with the programmed lysis (death) of the host and the release of dozens or hundreds of new phages. The use of phages as antimicrobial agents has a number of advantages over other methods. Phages are highly specific allowing for the removal of the targeted microorganisms from a mixed population. Unlike antibiotics ...
Bacterial viruses, or phage, are key members of natural microbial communities. Yet much research on bacterial-phage interactions has been conducted in liquid cultures involving single bacterial strains. Here we explored how bacterial diversity affects the success of lytic phage in structured communities. We infected a sensitive Pseudomonas aeruginosa strain PAO1 with a lytic phage Pseudomonas 352 in the presence versus absence of an insensitive P. aeruginosa strain PA14, in liquid culture versus colonies on agar. We found that both in liquid and in colonies, inter-strain competition reduced resistance evolution in the susceptible strain and decreased phage population size. However, while all sensitive bacteria died in liquid, bacteria in colonies could remain sensitive yet escape phage infection, due mainly to reduced growth in colony centers. In sum, spatial structure can protect bacteria against phage infection, while the presence of competing strains reduces the evolution of resista
Phage therapy is a medical approach for the treatment of bacterial infectious diseases which makes use of the natural ability of some viruses, known as bacteriophages, to kill specific bacteria that they recognize. Phage therapy was first proposed nearly a century ago at the Institut Pasteur by the French-Canadian scientist Félix dHerelle. Although the technique was initially used worldwide, from the 1940s onwards it was particularly developed in Eastern Europe, while Western countries gradually lost interest in the approach and preferred to focus their attention on antibiotics, thought to be more promising. Medical use of phage therapy is currently hindered by the viral nature of this antibacterial treatment and the lack of precise knowledge about how bacteriophages work.. However, given the rise in bacterial resistance to antibiotics and the worrying prospect of a potential therapeutic impasse, scientists are once again beginning to explore the possibilities of bacteriophages. This field has ...
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Phage therapy became very popular throughout the world in the early 20th century to treat a wide range of diseases caused by a variety of bacterial pathogens. After the discovery and production of penicillin for use during World War II, phage therapy fell out of favor in many western countries, particularly the US.. The phage therapy cocktails used in the past didnt always work and some of that had to do with phage strain selection and bacteria developing resistance to them. Today, though the use of synthetic genomics techniques and tools, standardized cocktails of phage can be rapidly and efficiently engineered to be more clinically effective than traditional phage cocktails created by mixing phage isolated from sewage.. Through their work, the JCVI team believes novel phage products can be developed that could lead to improved prevention and treatment for MDRO infections where few treatment options remain due to the spread of multidrug-resistance. Potential treatments would include topical ...
TY - JOUR. T1 - Bacteriophage lambda-based expression vectors. AU - Christensen, A. C.. PY - 2001/6/28. Y1 - 2001/6/28. N2 - Bacteriophage lambda has been in use as a cloning vector for over 25 years, and has been used extensively as an expression vector. The efficiency of packaging and infection, and the simplicity of plaque screening are advantages of lambda as a cloning vector. A number of ingenious modifications help overcome the disadvantages associated with its mode of growth and its size. Some lambda vectors have been designed to be readily converted into plasmids or phagemids, and there are a variety of promoters and fusions that can be used to drive expression of foreign genes. Screening lambda libraries with antibodies or ligands is a powerful way of identifying novel genes.. AB - Bacteriophage lambda has been in use as a cloning vector for over 25 years, and has been used extensively as an expression vector. The efficiency of packaging and infection, and the simplicity of plaque ...
We present a CRISPR-Cas based technique for deleting genes from the T7 bacteriophage genome. A DNA fragment encoding homologous arms to the target gene to be deleted is first cloned into a plasmid. The T7 phage is then propagated in Escherichia coli harboring this plasmid. During this propagation, some phage genomes undergo homologous recombination with the plasmid, thus deleting the targeted gene. To select for these genomes, the CRISPR-Cas system is used to cleave non-edited genomes, enabling isolation of the desired recombinant phages. This protocol allows seamless deletion of desired genes in a T7 phage, and can be expanded to other phages and other types of genetic manipulations as well.
Summary/Abstract: A fundamental, clinical and scientific concern is how lytic bacteriophage, as well as antibiotics, impact diagnostic positivity. Cholera was chosen as a model disease to investigate this important question because cholera outbreaks enable large enrollment, field methods are well established, and the predatory relationship between lytic bacteriophage and the etiologic agent Vibrio cholerae share commonalities across bacterial taxa. Patients with diarrheal disease were enrolled at two remote hospitals in Bangladesh. Diagnostic performance was assessed as a function of lytic bacteriophage detection and exposure to the first-line antibiotic azithromycin detected in stool samples by mass spectrometry. Among diarrheal samples positive by nanoliter quantitative PCR for V. cholerae (n=78/849), the odds that a rapid diagnostic test (RDT) or qPCR was positive was reduced by 89% (OR 0.108; 95%CI 0.002-0.872) and 87% (OR 0.130; 95%CI 0.022-0.649) when lytic bacteriophage were detected, ...
Phage Therapy and Phage Resistance scheduled on March 02-03, 2020 in March 2020 in Rio de Janeiro is for the researchers, scientists, scholars, engineers, academic, scientific and university practitioners to present research activities that might want to attend events, meetings, seminars, congresses, workshops, summit, and symposiums.
This issue profiles a bacteriophage that aids efforts to destroy Enterococcus Faecalis bacteria, preventing salmonellosis through the usage of lytic bacteriophages, and development of multiple phage therapy products for infectious diseases .
Bacteriophages are viruses that infect specific bacterial hosts in order to grow and replicate. Because bacteriophages are miniscule in size, it is not possible to obtain images of the structural features using light microscopy. Transmission electron microscopy (TEM) is a useful technique to view images with higher resolution and magnification using electrons to illuminate the subject. This technique allows for clear visualization of bacteriophage structural features, including the head, capsid, and tail. Bacteriophages isolated from infections of the bacterial host Rhodobacter capsulatus, which include RcTitan, RcOceanus, RcSpartan, RcRhea, RcSaxon, and RcCronus, were examined. In order to obtain contrast, new lysates of each phage were placed on a formvar coated 200-mesh grid and stained with uranyl acetate. The negative stain from uranyl acetate allowed for high contrast, as the background is stained, while the phage is not and thus visible. Bacteriophage morphology, such as head sizes and tail
For genomic DNA extraction, bacteriophage SfΦ01 was inoculated to S. flexneri grown in R2A medium and incubated overnight at 37°C. Bacterial cells were removed by centrifugation and filtration with a 0.45-μm-pore-size filter. Bacteriophage particles were concentrated using the Centricon Plus-70 filter (Merck Millipore), and 160 μl of bacteriophage concentrate was mixed with 20 μl of DNase I (Promega) to digest free DNA. Bacteriophage genomic DNA was extracted from the resultant sample using the PowerBiofilm DNA isolation kit (Mo Bio Laboratories). Sequencing libraries were prepared using the TruSeq PCR-free library prep kit (Illumina) with an insert fragment size of ca. 350 bp and paired-end sequenced by using the MiSeq platform (Illumina) with v2 chemistry (250 cycles). The sequencing reads (541,594 reads each for forward and reverse sequencing reactions) were assembled de novo by using the SPAdes v. 3.12 program (10). The genome assembly depth (coverage) was 1,618. Genes were predicted by ...
Caspar and Klug (50) had predicted that, for each of the covalently identical subunits that compose the surface of a virus to have identical environments, it would require that the subunits are organized into an hexagonal array. An icosahedron is formed by substituting a pentagon of subunits for a hexagon of subunits at regular positions. This would then allow each subunit to have at least a quasi-equivalent environment. The total size of the assembly is determined by where the pentamers replace hexamers. This prediction has been found to be true in a large variety of viruses with T numbers varying from 1 for the smallest viruses such a parvoviruses (51) and the ΦX174 bacteriophage (52) to very large dsDNA viruses with T numbers of 169 [PBCV-1 (53⇓-55)] and 972 ≤ T ≤ 1,200 [Mimivirus (56)]. Here we have determined the structure of a virus with a T=13 lattice, which makes it possible to examine how the assembly process has introduced pentamers at specific positions in the hexagonal ...
Further, to address the critical question of whether adding spacers provides novel phage resistance, we replaced the CRISPR1 locus of strain WTΦ2972+S4 with a version containing only spacers S1 and S2 (12) and tested whether the phage sensitivity was affected. Remarkably, the resulting strain WTΦ2972+S4::pS1S2 gained resistance to phage 858, which suggested that these two spacers have the ability to provide phage resistance de novo (Fig. 3). Altogether, these observed modifications establish the link between the CRISPR spacer content and phage resistance.. In the process of generating strain WTΦ858+S1S2ΔCRISPR1, we created WTΦ858+S1S2::pR, a variant that contains the integration vector with a single repeat inserted between the cas genes and the native CRISPR1 locus (Fig. 3). Unexpectedly, strain WTΦ858+S1S2::pR was sensitive to phage 858, although spacers S1 and S2 remained on the chromosome (Fig. 3). Similarly, the WTΦ2972+S4::pS1S2 construct lost the resistance to phage 2972, although ...
Bacteriophages were first described by Frederick Twort in 1915 as agents that destroyed bacteria, leaving small areas of destruction (plaques) on bacterial lawns. It is now one hundred years later and we have made great advances both in our understanding of bacteriophage biology and how to use these viruses as tools to understand basic, general principles of biology including DNA being the hereditary material of life. Because 2015 was one hundred years following the first description of phages, it has been termed the year of the phage by many scientists. Not only does this year bear symbolic importance, but it actually marks some important advances in the field of phage therapy. Because we are nearing the end of the year of the phage, I thought it would be appropriate to briefly go over some of the advances I thought stood out the most ...
As a member of the wwPDB, the RCSB PDB curates and annotates PDB data according to agreed upon standards. The RCSB PDB also provides a variety of tools and resources. Users can perform simple and advanced searches based on annotations relating to sequence, structure and function. These molecules are visualized, downloaded, and analyzed by users who range from students to specialized scientists.
Zimecki and colleagues describe the benefits of combined action of lactoferrin and phages in the treatment of infection of Escherichia coli and S. aureus in mice (12). Lactoferrin (LF) is a protein found in the secretory fluids of mammals and the secondary granules of neutrophils, and exhibits both antibacterial and anti-inflammatory actions. It has also been shown to enhance neutrophil production. In the experiment, mice were injected with E. coli and S. aureus, while the E. coli and S. aureus specific bacteriophages were administered intraperitoneally or orally one hour after bacteria injection. Lactoferrin was injected intravenously 24 hours before infection. The results showed that both oral and intraperritoneal phage administration proved effective in reducing numbers of bacteria in the liver, but the combined action of bacteriophages and LF produced a significant additive effect.. Fischetti and colleagues studied the antibacterial effect of bacteriophage lysins in various types of ...
The next step in dHerelles studies was to try and treat dysentery with his newly discovered bacteriophages. The study was conducted in 1919 in Paris after dHerelle proved the safety of his bacteriophages by having himself and all of the clinical staff involved as the first to ingest the bacteriophage preparation the day before! You can almost hear the conversation the next day...we survived the night so lets give it to a patient (wasnt experimental medicine great in those days...for those that survived)! The preparation was then given to a 12 year old boy who was dying from dysentery and within a day he was much improved and a few days later he was cured. Further patients were successfully treated and dHerelle was so convinced of his findings that he subsequently went on to treat thousands of patients with cholera and bubonic plague in India with various new bacteriophage preparations. Gosh, there seems there might be something exciting in this! However, dHerelle is also historically ...
Bacteriophage are viruses that infect bacteria. They were discovered independently by Frederick W. Twort in England in 1915 and by Felix d Herelle
Using continuous reaction norms to characterize adaptive responses to temperature, the researchers reexamined a recent study that linked rapid adaptation to specific genetic changes. The study, by Holder and Bull, showed that phage populations quickly evolved higher growth rates at higher temperatures. But, Knies et al. explain, these growth rates were correlated with just one temperature point the optimal temperature for the ancestral populations (used at the beginning of the experiment). Knies et al. reexamined phage thermal adaptation by measuring growth rate over a wider range of temperatures, then used a recently developed statistical method to identify the biological determinants of the shifts in the reaction norm shapes, quantify their relative contributions, and identify the genetic basis of the adaptations ...
The increase of multi-resistant bacteria highlights that the golden era of antibiotics is ending and that alternative treatmentsare urgently needed. Phages have been historically used to treat bacterial infections prior to the discovery of antibiotics and have gained renewed interest in the past decade. Despite the advantages of phage therapy over traditional antibiotic usage, a number of concerns persist over their clinical application centring on their efficacy and safety. This thesis presents four papers that focus on the isolation and characterization of phages that target reference strains and drug-resistant strains of E. coli as well as their infection dynamics and kinetics. In Paper I, six of thirty isolated phages were selected to be characterized for their growth parameters and host range using two commonly used methods. The study showed that the host range (an important selection criteria for phages) of the phages can change based on the assessment method and that the lysis efficiency ...
The largest bacteriophage genomes reach a size of 735 kb. Bacteriophage genomes can be highly mosaic, i.e. the genome of many ... Bacteriophages are among the most common and diverse entities in the biosphere. Bacteriophages are ubiquitous viruses, found ... "T4 Bacteriophage targeting E. coli bacteria". Animation by Hybrid Animation Medical. 21 December 2009. Bacteriophages: What are ... Basic research - Bacteriophages are important model organisms for studying principles of evolution and ecology. Bacteriophages ...
Bacteriophage Qβ enters its host cell after binding to the side of the F-pilus. The genome of Qβ is approximately 4,217 ... In bacteriophage MS2, the maturation protein is called the A protein, as it belongs to the first open reading frame in the ... Bacteriophage Qbeta (Qubevirus durum), commonly referred to as Qbeta or Qβ, is a positive-strand RNA virus which infects ... RNA from Bacteriophage Qβ was used by Sol Spiegelman in experiments that favored faster replication, and thus shorter strands ...
... is a bacteriophage that infects Caulobacter bacteria and other caulobacteria. The bacteriophage was ... The bacteriophage is similar to the RNA bacteriophages of Escherichia in that it is composed of a single positive single- ... The φCb5 bacteriophage differs from Escherichia RNA bacteriophages in host specificity, salt sensitivity, and the presence of ... As for related bacteriophages, ORFs encode maturation, coat, RNA replicase, and lysis proteins, but unlike other members of ...
A moron, in the context of bacteriophage genetics, is an extra gene in a prophage genome without a function in the phage's ... The term moron comes from the notion that the additional genes mean that these bacteriophage genomes have "more on" them. ... Cumby, N; Davidson, AR; Maxwell, KL (2012). "The moron comes of age". Bacteriophage. 2 (4): 225-228. doi:10.4161/bact.23146. ... v t e (DNA, Bacteriophages, All stub articles, Virus stubs). ...
... is a bacteriophage that infects Acinetobacter bacteria. Contains a genome linear of positive single- ... The bacteriophage belongs to the genus Apeevirus of the Duinviridae family and is the type species of the family. Dann Turner, ... Comparative Analysis of 37 Acinetobacter Bacteriophages. MDPI. Callanan J, Stockdale SR, Adriaenssens EM, Kuhn JH (January 2021 ...
It is closely related to bacteriophage MS2 and assigned to the same species. f2 was the first RNA-containing bacteriophage to ... Bacteriophage f2 is an icosahedral, positive-sense single-stranded RNA virus that infects the bacterium Escherichia coli. ... Loeb, T.; Zinder, N. D. (1961). "A bacteriophage containing RNA". Proc. Natl. Acad. Sci. USA. 47 (3): 282-289. Bibcode:1961PNAS ... Chapter 15". In Calendar, R. L. (ed.). The Bacteriophages (Second ed.). Oxford University Press. pp. 175-196. ISBN 0195148509. ...
... is a bacteriophage that infects the bacterial species Streptococcus pyogenes. It is a proposed species of the ... NCBI: Bacteriophage T12 (species) W. M. McShan; Y. F. Tang; J. J. Ferretti (1997). "Bacteriophage T12 of Streptococcus pyogenes ... Bacteriophage T12, proposed member of family Siphoviridae including related speA-carrying bacteriophages, is also a prototypic ... This mutant, the bacteriophage T12cp1, entered the lytic cycle, a life cycle in which the host cell is destroyed. In 1983, ...
... , also known as mu phage or mu bacteriophage, is a muvirus (the first of its kind to be identified) of the ... 2002), "Bacteriophage Mu genome sequence: analysis and comparison with Mu-like prophages in Haemophilus, Neisseria and ... created a crystal structure of the Mu bacteriophage transpososome, allowing for a detailed understanding of the process Mu ... Montano SP, Pigli YZ, Rice PA (2012). "4FCY: Crystal Structure of the Bacteriophage MU Transpososome". Nature. 491: 413-417. ...
The P2-like bacteriophages. In R. Calendar (ed.), The bacteriophages. Oxford Press, Oxford, 2005: p. 365-390 Lindahl, G., ... Bacteriophage P2 was first isolated by G. Bertani from the Lisbonne and Carrère strain of E. coli in 1951. Since that time, a ... Bacteriophage P2, scientific name Escherichia virus P2, is a temperate phage that infects E. coli. It is a tailed virus with a ... Bacteriophage P2 is a temperate phage, which means that it can propagate lytically (i.e. directing the host cell to produce ...
Page for Bacteriophage pRNA at Rfam v t e (Non-coding RNA, Bacteriophages, All stub articles, Molecular and cellular biology ... Bacteriophage pRNA is a ncRNA element. During replication of linear dsDNA viruses, the viral genome is packaged into the pre- ... In some bacteriophage, an RNA (pRNA) molecule is a vital component of this motor. Structural analyses of the packaging motor ... Guo PX, Erickson S, Anderson D (1987). "A small viral RNA is required for in vitro packaging of bacteriophage phi 29 DNA". ...
M13 is one of the Ff phages (fd and f1 are others), a member of the family filamentous bacteriophage (inovirus). Ff phages are ... Khalil AS, Ferrer JM, Brau RR, Kottmann ST, Noren CJ, Lang MJ, Belcher AM (March 2007). "Single M13 bacteriophage tethering and ... Suthiwangcharoen N, Li T, Li K, Thompson P, You S, Wang Q (May 2011). "M13 bacteriophage-polymer nanoassemblies as drug ... Phage display Phagemid Filamentous bacteriophage Smeal SW, Schmitt MA, Pereira RR, Prasad A, Fisk JD (January 2017). " ...
... is a bacteriophage that infects the spore-forming bacterium Bacillus cereus. Kong, M; Kim, M; Ryu, S (June ... 2012). "Complete Genome Sequence of Bacillus cereus Bacteriophage PBC1". Journal of Virology. 86 (11): 6379-80. doi:10.1128/JVI ...
Giles is a bacteriophage that infects Mycobacterium smegmatis bacteria. The genome of this phage is very different from that of ... "Functional requirements for bacteriophage growth: gene essentiality and expression in mycobacteriophage Giles". Molecular ...
species Escherichia virus M13 M13 bacteriophage f1 phage species Filamentous bacteriophage fd (proposal) fd phage genus ... inactivated infectivity as predicted for a filamentous bacteriophage morphology. Three filamentous bacteriophages, fd, f1 and ... Filamentous bacteriophage is a family of viruses (Inoviridae) that infect bacteria. The phages are named for their filamentous ... Three filamentous bacteriophages, fd, f1 and M13, were isolated and characterized by three different research groups in the ...
Viruses portal bacteriophage bacteriophage f2 bacteriophage Qβ phi-X174 phage van Duin J, Tsareva N (2006). "Single-stranded ... MS2 is a member of a family of closely related bacterial viruses that includes bacteriophage f2, bacteriophage Qβ, R17, and GA ... Bacteriophage MS2 (Emesvirus zinderi), commonly called MS2, is an icosahedral, positive-sense single-stranded RNA virus that ... In 1961, MS2 was isolated by Alvin John Clark and recognized as an RNA-containing phage very similar to bacteriophage f2. In ...
In molecular biology, bacteriophage scaffolding proteins are proteins involved in bacteriophage assembly. The assembly of a ... In bacteriophage, scaffolding proteins B and D are responsible for procapsid formation. 240 copies of protein D form the ...
The CTXφ bacteriophage is a filamentous bacteriophage. It is a positive-strand DNA virus with single-stranded DNA (ssDNA). CTXφ ... After the production of the proteins and genomic material necessary to create new virion forms of the bacteriophage, the ...
Long-circulating bacteriophage as antibacterial agents. Proc. Natl. Acad. Sci. USA 93:3188-3192. Gupta, K., Y. Lee and J. Yin. ... Lysis timing and bacteriophage fitness. Genetics 172:17-26. Abedon, S. T., P. Hyman, and C. Thomas. 2003. Experimental ... Drift increases the advantage of sex in RNA bacteriophage Turner, P. E., and L. Chao. 1998. Sex and the evolution of intrahost ... Coevolution of bacteriophage PP01 and Escherichia coli O157:H7 in continuous culture. Appl. Environ. Microbiol. 69:170-176. ...
Bacteriophages. Interscience, New York. OCLC 326505 Ho, N. B., Z. T. Si, and M. X. Yu. 1959. Bacteriophages from China. An ... French; The Bacteriophage and its Behavior] OCLC 11981307 d'Hérelle, F., and G. H. Smith. 1926. The Bacteriophage and Its ... The Bacteriophages. Volume I Plenum Press, New York. OCLC 18686137 Calendar, R. 1988. The Bacteriophages. Volume II Plenum ... French; The Bacteriophage: Its Nature and its Therapeutic Employment] OCLC 14735726 Flu, P. C. 1946. The Bacteriophage: A ...
Bacteriophage T7 (or the T7 phage) is a bacteriophage, a virus that infects bacteria. It infects most strains of Escherichia ... Bacteriophage T7 has a lytic life cycle, meaning that it destroys the cell it infects. It also possesses several properties ... T7 bacteriophage has been evolved to override several of the host bacteria's defenses including the peptidoglycan cell wall and ... "Genome of bacteriophage T7". Retrieved 18 May 2011. Dunn, J. J.; Studier, F. W. (1983). "Complete nucleotide sequence of ...
The Bacteriophages. Oxford University Press. 638-639. Saglio, P; Lhospital, M; Laflèche, D; Dupont, G; Bové, JM; Tully, JG; ... Spiroplasma phage 1-R8A2B is a filamentous bacteriophage in the genus Vespertiliovirus of the family Plectroviridae, part of ...
Bacteriophages are viruses that infect and replicate within a bacterium. Temperate phages (such as lambda phage) can reproduce ... Bacteriophages are parasitic because they infect their hosts, use bacterial machinery to replicate, and ultimately lyse the ... Since the bacteriophage's genetic information is incorporated into the bacteria's genetic information as a prophage, the ... "Bacteriophages (article) , Viruses". Khan Academy. Retrieved 2022-03-15. Quiberoni, A.; Suárez, V. B.; Binetti, A. G.; ...
T4-like viruses Animation of T4 Bacteriophage Infecting E.coli Animation of T4 Bacteriophage DNA packaging (Articles with short ... "Genetic Recombinations Leading to Production of Active Bacteriophage from Ultraviolet Inactivated Bacteriophage Particles". ... Molecular Biology of Bacteriophage T4. ASM Press, Washington, DC. (The second T4 bible, go here, as well as Mosig and Eiserling ... Bacteriophages were first discovered by the English scientist Frederick Twort in 1915 and Félix d'Hérelle in 1917. In the late ...
Bacteriophage PM2 was first described in 1968 after isolation from seawater sampled from the coast of Chile. The genus contains ... Corticoviruses are bacteriophages; that is, their natural hosts are bacteria. The genus contains two species. The name is ... Harrison, S.C., Caspar, D.L., Camerini-Otero, R.D. and Franklin, R.M. (1971). Lipid and protein arrangement in bacteriophage ... Kiveld, H.M., Kalkkinen, N. and Bamford, D.H. (2002). Bacteriophage PM2 has a protein capsid surrounding a spherical lipid- ...
Relatively few bacteriophages are known to infect B. burgdorferi. Several phage particles were isolated and some evidence ... Current research aims to use bacteriophages as way of identifying virulence factors in spirochaetes that lead to Lyme Disease.[ ... φBB-1 was the first bacteriophage that provided evidence of transduction for lateral gene transfer in Borrelia species that ... a Bacteriophage of Borrelia burgdorferi". Journal of Bacteriology. 183 (16): 4771-4778. doi:10.1128/JB.183.16.4771-4778.2001. ...
The primary cause of a lower than expected phage concentration was due to storage instability of the bacteriophages used in the ... Phagoburn was a European Union-financed phase I/II clinical study focused on testing the medical uses of bacteriophage for ... 2018). "Efficacy and tolerability of a cocktail of bacteriophages to treat burn wounds infected by Pseudomonas aeruginosa ( ... "Bacteriophages and Biofilms". Antibiotics. 3 (3): 270-284. doi:10.3390/antibiotics3030270. PMC 4790368. Patrick Jault; Thomas ...
The bacteriophages can be delivered orally and result in destruction of C. difficile within two days. Clokie went on to ... The bacteriophage could reduce the growth of C. difficile and simultaneously defend beneficial bacterial that are typically ... Clokie, Martha (2009). Bacteriophages: Methods and Protocols. Springer Protocols. ISBN 978-1-60327-564-4. Clokie, Martha R. J ... She is interested in viruses known as bacteriophages which can be used to treat disease. Her work involves cyanobacteria and ...
Bacteriophages (phages) Bacteria defend themselves from bacteriophages by producing enzymes that destroy foreign DNA. These ... Bacteriophages are harmless to plants and animals but are essential to the regulation of marine ecosystems. They supply key ... Bacteriophages are harmless to plants and animals, and are essential to the regulation of marine and freshwater ecosystems are ... Marine bacteriophages play an important role in deep sea ecosystems. There are between 5x1012 and 1x1013 phages per square ...
Bacteriophage Lambda binds to an E. coli cell by means of its J protein in the tail tip. The J protein interacts with the ... Campbell, A.M. Bacteriophages. In: Neidhardt, FC et al. (1996) Escherichia coli and Salmonella typhimurium: Cellular and ... Burz DS, Beckett D, Benson N, Ackers GK (July 1994). "Self-assembly of bacteriophage lambda cI repressor: effects of single- ... Friedman DI, Court DL (April 2001). "Bacteriophage lambda: alive and well and still doing its thing". Current Opinion in ...
Clokie, Martha R. J.; Kropinski, Andrew M. (Andrew Maitland Boleslaw) (2009). Bacteriophages : methods and protocols. Humana ...

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