A BACTERIOPHAGE THAT ATTACKS NUMEROUS PHYTOPATHOGENIC XANTHOMONAS SPECIES

1958 ◽  
Vol 4 (5) ◽  
pp. 493-497 ◽  
Author(s):  
M. D. Sutton ◽  
H. Katznelson ◽  
C. Quadling
Keyword(s):  
Burst Size ◽  
Lytic Phage ◽  
Plant Materials ◽  
Single Burst ◽  
Xanthomonas Species ◽  
One Step ◽  
Average Burst Size ◽  
Step Growth ◽  
Rot Disease

This paper reports the isolation of a lytic phage that attacks in vitro numerous phytopathogenic Xanthomonas species, including X. campestris (Pammel) Dowson, the cause of black rot disease of crucifers. Although 'one-step' growth experiments suggested an average burst size of ca. four for this phage-host system, 'single burst' experiments indicated a burst size of ca. one hundred phage particles per bacterium. The particles have typical phage morphology, as determined by electron microscopy. This phage gave satisfactory results when used in the rapid plaque count test for detection of phage-sensitive bacteria in plant materials.

Isolation and characterization of two bacteriophages of a stem-nodulating Rhizobium strain from Sesbania rostrata

1984 ◽  
Vol 30 (5) ◽  
pp. 521-525 ◽  
Author(s):  
Philippe de Lajudie ◽  
Didier Bogusz
Keyword(s):  
Burst Size ◽  
Growth Cycle ◽  
Sesbania Rostrata ◽  
Isolation And Characterization ◽  
Rhizobium Strains ◽  
One Step ◽  
Average Burst Size ◽  
Step Growth ◽  
Phage Growth

Two rhizobiophages, RS1 and RS2, were isolated in Senegal from a soil sample and dry stem nodules of Sesbania rostrata, a tropical legume that is infected by two categories of Rhizobium strains: "stem strains," which nodulate both roots and stems (type strain, ORS571), and "root strains," which induce effective nodules only on roots. Both phages were found to have a host range restricted to ORS571; all root strains were found to be resistant. By electron microscopy, phage RS1 showed an hexagonal head 63 nm wide and a tail 87 nm long; phage RS2 revealed an hexagonal head 60 nm wide. Characterization of phage growth cycle by one-step growth experiments showed that the latent period was ca. 75 min for RS1 and ca. 4 h for RS2, that the rise period lasted ca. 2 h for both RS1 and RS2, and that the average burst size was ca. 100 for RS1 and 130 for RS2. Temperature denaturation occurred at 60–65 °C (RS1) and 45–50 °C (RS2). Serum neutralization tests revealed that the phages were not serologically related. In contrast to RS1, RS2 appeared to be temperate, since stable lysogens were isolated.

scholarly journals Aztreonam Lysine Increases the Activity of Phages E79 and phiKZ against Pseudomonas aeruginosa PA01

2021 ◽  
Vol 9 (1) ◽  
pp. 152
Author(s):  
Carly M. Davis ◽  
Jaclyn G. McCutcheon ◽  
Jonathan J. Dennis
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Morphological Changes ◽  
Burst Size ◽  
Type Iv Pili ◽  
Biofilm Growth ◽  
Promising Alternative ◽  
Type Iv ◽  
Alternative Treatment Option ◽  
One Step ◽  
Step Growth

Pseudomonas aeruginosa is a pernicious bacterial pathogen that is difficult to treat because of high levels of antibiotic resistance. A promising alternative treatment option for such bacteria is the application of bacteriophages; the correct combination of phages plus antibiotics can produce synergistic inhibitory effects. In this study, we describe morphological changes induced by sub-MIC levels of the antibiotic aztreonam lysine (AzLys) on P. aeruginosa PA01, which may in part explain the observed phage–antibiotic synergy (PAS). One-step growth curves for phage E79 showed increased adsorption rates, decreased infection latency, accelerated time to lysis and a minor reduction in burst size. Phage E79 plus AzLys PAS was also able to significantly reduce P. aeruginosa biofilm growth over 3-fold as compared to phage treatment alone. Sub-inhibitory AzLys-induced filamentation of P. aeruginosa cells resulted in loss of twitching motility and a reduction in swimming motility, likely due to a reduction in the number of polar Type IV pili and flagella, respectively, on the filamented cell surfaces. Phage phiKZ, which uses Type IV pili as a receptor, did not exhibit increased activity with AzLys at lower sub-inhibitory levels, but still produced phage–antibiotic synergistic killing with sub-inhibitory AzLys. A one-step growth curve indicates that phiKZ in the presence of AzLys also exhibits a decreased infection latency and moderately undergoes accelerated time to lysis. In contrast to prior PAS studies demonstrating that phages undergo delayed time to lysis with cell filamentation, these PAS results show that phages undergo accelerated time to lysis, which therefore suggests that PAS is dependent upon multiple factors, including the type of phages and antibiotics used, and the bacterial host being tested.

The influence of radiomimetic substances on deoxyribonucleic acid synthesis and function studied in Escherichia coli / phage systems - III. Mutation of T 2 bacteriophage as a consequence of alkylation in vitro : the uniqueness of ethylation

1959 ◽  
Vol 150 (941) ◽  
pp. 497-508 ◽  
Keyword(s):  
Escherichia Coli ◽  
Burst Size ◽  
Alkylating Agents ◽  
Direct Consequence ◽  
Acid Synthesis ◽  
Deoxyribonucleic Acid Synthesis ◽  
Methane Sulphonate ◽  
Average Burst Size ◽  
And Function

Of a comprehensive set of alkylating agents tested, only two, namely, ethyl methane sulphonate and diethyl sulphate, have been found so to interact with T 2 bacteriophage that cells of Escherichia coli , infected with phage treated extracellularly, manifest a considerably increased likelihood of yielding mutated phage. Since this increase can occur where the infective titre of the phage and the latent period and average burst size of the infected bacteria remain unchanged, it is considered that the increased mutation rate is a direct consequence of the chemical treatment, although the alkylation itself does not constitute the mutation. A study of the manner of inactivation of the phage by these agents has not revealed any characteristic difference between ethylation and other alkylations which could be held to account for its apparent uniqueness.

scholarly journals Random Transposon-Mediated Mutagenesis of the Essential Large Tegument Protein pUL36 of Pseudorabies Virus

2010 ◽  
Vol 84 (16) ◽  
pp. 8153-8162 ◽  
Author(s):  
Britta S. Möhl ◽  
Sindy Böttcher ◽  
Harald Granzow ◽  
Walter Fuchs ◽  
Barbara G. Klupp ◽  
...  
Keyword(s):  
Amino Acids ◽  
Pseudorabies Virus ◽  
Plaque Assay ◽  
Tegument Protein ◽  
Nuclear Pore ◽  
Viral Spread ◽  
One Step ◽  
Step Growth ◽  
Insertion Mutants

ABSTRACT Homologs of the pseudorabies virus (PrV) essential large tegument protein pUL36 are conserved throughout the Herpesviridae. pUL36 functions during transport of the nucleocapsid to and docking at the nuclear pore as well as during virion formation after nuclear egress in the cytoplasm. Deletion analyses revealed several nonessential regions within the 3,084-amino-acid PrV pUL36 (S. Böttcher, B. G. Klupp, H. Granzow, W. Fuchs, K. Michael, and T. C. Mettenleiter, J. Virol. 80:9910-9915, 2006; S. Böttcher, H. Granzow, C. Maresch, B. Möhl, B. G. Klupp, and T. C. Mettenleiter, J. Virol. 81:13403-13411, 2007), while the C-terminal 62 amino acids are essential for virus replication (K. Coller, J. Lee, A. Ueda, and G. Smith, J. Virol. 81:11790-11797, 2007). To identify additional functional domains, we performed random mutagenesis of PrV pUL36 by transposon-mediated insertion of a 15-bp linker. By this approach, 26 pUL36 insertion mutants were selected and tested in transient transfection assays for their ability to complement one-step growth and/or viral spread of a PrV UL36 null mutant. Ten insertion mutants in the N-terminal half and 10 in the C terminus complemented both, whereas six insertion mutants clustering in the center of the protein did not complement in either assay. Interestingly, several insertions within conserved parts yielded positive complementation, including those located within the essential C-terminal 62 amino acids. For 15 mutants that mediated productive replication, stable virus recombinants were isolated and further characterized by plaque assay, in vitro growth analysis, and electron microscopy. Except for three mutant viruses, most insertion mutants replicated like wild-type PrV. Two insertion mutants, at amino acids (aa) 597 and 689, were impaired in one-step growth and viral spread and exhibited a defect in virion maturation in the cytoplasm. In contrast, one functional insertion (aa 1800) in a region which otherwise yielded only nonfunctional insertion mutants was impaired in viral spread but not in one-step growth without a distinctive ultrastructural phenotype. In summary, these studies extend and refine previous analyses of PrV pUL36 and demonstrate the different sensitivities of different regions of the protein to functional loss by insertion.

scholarly journals PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES

1950 ◽  
Vol 34 (2) ◽  
pp. 231-250 ◽  
Author(s):  
Winston H. Price
Keyword(s):  
Aspartic Acid ◽  
Burst Size ◽  
Synthetic Medium ◽  
Growth Curves ◽  
Acid Synthesis ◽  
Virus Protein ◽  
Complete Medium ◽  
Multiplication Rate ◽  
One Step ◽  
Step Growth

1. Four strains of Staphylococcus muscae have been isolated which differ in their growth rates and phage syntheses in Fildes' synthetic medium. 2. Two of the strains when singly infected cannot release phage in Fildes' synthetic medium unless a substance present in certain acid-hydrolyzed proteins is added to the medium. One of these strains also requires other substance(s) present in acid-hydrolyzed proteins in order to grow in Fildes' medium. 3. The two strains which do not require the addition of the phage-stimulating factor have been found either to synthesize this substance, or one similar to it. One of these strains will not grow in Fildes' medium unless substance(s) present in acid-hydrolyzed proteins is added to the medium. 4. The purified acid-hydrolyzed protein factor necessary for virus liberation does not affect the multiplication rate of uninfected S. muscae cells in Fildes' synthetic medium. 5. The substance is not needed for the adsorption or the invasion of the host cell by the virus. In the absence of the factor, the virus is adsorbed to the cell and "kills" it. 6. An analysis carried out by means of the one-step growth curve technique has indicated that the substance is not concerned simply with the mechanism of virus release, but is necessary for some initial stage in virus synthesis. 7. With one bacterial strain not requiring the AHPF, aspartic acid had to be present at least during the minimum latent period for the cell to form virus. 8. In the absence of aspartic acid, the virus was adsorbed to the cell and killed it, but no virus was released from singly infected bacteria. 9. If the cells were grown in a medium containing aspartic acid and then resuspended in the medium minus aspartic acid, no virus was released, although such cells contained at least two times the amount of aspartic acid necessary for the burst size in the complete medium. 10. Aspartic acid, a constituent of the virus particle, appears from an analysis of one-step growth curves to take part in the initial phase of phage synthesis. 11. The effect of amino acids on virus formation is discussed in relation to the time sequence of virus protein and desoxyribonucleic acid synthesis.

scholarly journals Bacteriophage φYeO3-12, Specific forYersinia enterocolitica Serotype O:3, Is Related to Coliphages T3 and T7

2000 ◽  
Vol 182 (18) ◽  
pp. 5114-5120 ◽  
Author(s):  
Maria Pajunen ◽  
Saija Kiljunen ◽  
Mikael Skurnik
Keyword(s):  
Physical Map ◽  
Burst Size ◽  
Restriction Enzymes ◽  
Structural Proteins ◽  
Close Relative ◽  
Lytic Phage ◽  
Serotype O ◽  
One Step ◽  
Phage Capsid ◽  
Phage Receptor

Bacteriophage φYeO3-12 is a lytic phage of Yersinia enterocolitica serotype O:3. The phage receptor is the lipopolysaccharide O chain of this serotype that consists of the rare sugar 6-deoxy-l-altropyranose. A one-step growth curve of φYeO3-12 revealed eclipse and latent periods of 15 and 25 min, respectively, with a burst size of about 120 PFU per infected cell. In electron microscopy φYeO3-12 virions showed pentagonal outlines, indicating their icosahedral nature. The phage capsid was shown to be composed of at least 10 structural proteins, of which a protein of 43 kDa was predominant. N-terminal sequences of three structural proteins were determined, two of them showing strong homology to structural proteins of coliphages T3 and T7. The phage genome was found to consist of a double-stranded DNA molecule of 40 kb without cohesive ends. A physical map of the phage DNA was constructed using five restriction enzymes. The phage infection could be effectively neutralized using serum from a rabbit immunized with whole φYeO3-12 particles. The antiserum also neutralized T3 infection, although not as efficiently as that of φYeO3-12. φYeO3-12 was found to share, in addition to the N-terminal sequence homology, several common features with T3, including morphology and nonsubjectibility to F exclusion. The evidence conclusively indicated that φYeO3-12 is the first close relative of phage T3 to be described.

scholarly journals Isolation of a Novel Bacteriophage Specific for the Periodontal Pathogen Fusobacterium nucleatum

2010 ◽  
Vol 76 (21) ◽  
pp. 7243-7250 ◽  
Author(s):  
Pamela Machuca ◽  
Leslie Daille ◽  
Enrique Vinés ◽  
Liliana Berrocal ◽  
Mauricio Bittner
Keyword(s):  
Periodontal Disease ◽  
Burst Size ◽  
Fusobacterium Nucleatum ◽  
Amino Acid Identity ◽  
Periodontal Pathogen ◽  
Genetic Characteristics ◽  
Double Stranded Dna ◽  
Transmission Electron ◽  
One Step ◽  
Step Growth

ABSTRACT Fusobacterium nucleatum is a periodontal pathogen that has been directly associated with the development and progression of periodontal disease, a widespread pathology that affects the support tissues of the tooth. We isolated a new bacteriophage (FnpΦ02) that specifically infects this bacterium. Transmission electron microscopy showed that the virion is composed of an icosahedral head and a segmented tail. The size of the phage genome was estimated to be approximately 59 kbp of double-stranded DNA. The morphological features and the genetic characteristics suggest that FnpΦ02 is part of the Siphoviridae family. Using one-step growth and adsorption experiments, the latent period, burst size, and adsorption rate were estimated to be 15 h, 100 infectious units per cell, and 7.5 × 10−10 ml min−1, respectively. A small fragment of phage DNA was cloned and sequenced, showing 93% nucleotide identity with the phage PA6 of Propionibacterium acnes and amino acid identity with fragments of two proteins (Gp3 and Gp4) of this phage. To our knowledge, FnpΦ02 is the first phage described to infect Fusobacterium nucleatum and provides the base for future exploration of phages in the control of periodontal disease.

scholarly journals CHARACTERIZATION OF T4 MUTANTS THAT PARTIALLY SUPPRESS THE INABILITY OF T4rII TO GROW IN LAMBDA LYSOGENS

Genetics ◽  
1976 ◽  
Vol 83 (3) ◽  
pp. 477-487
Author(s):  
Theodore Homyk ◽  
Angel Rodriguez ◽  
Jon Weil
Keyword(s):  
Burst Size ◽  
Personal Communication ◽  
Growth Cycle ◽  
Plaque Morphology ◽  
One Step ◽  
Step Growth ◽  
The One ◽  
Phage Growth ◽  
L1 And L2

ABSTRACT In the course of isolating viable T4 deletions that affect plaque morphology (Homyk and Weil 1974), two closely linked point mutants, sip1 and sip2, were obtained. They map between genes t and 52, cause a reduction in plaque size and burst size, and partially suppress the lethality of rII mutants for growth in lambda lysogens. These characteristics demonstrate that sip1 and sip2 are similar to mutants previously reported by Freedman and Brenner (1972). In addition, D. Hall (personal communication) has shown that sip1 and sip2 are similar to the mutant farP85, which affects the regulation of a number of early genes (Chace and Hall 1975).—Sip suppression of rII mutants can be demonstrated in one-step growth experiments, even when both rII genes are completely deleted. This indicates that sip mutants do not simply reduce the level of rII gene products required for growth in a lambda lysogen. Instead, they alter the growth cycle so as to partially circumvent the need for any rII products.—Mutations at two other sites, designated L1 and L2, reverse the poor phage growth caused by sip and, in the one case tested, reverse the rII-suppressing ability of sip.

scholarly journals ONE-STEP GROWTH CURVE OF WESTERN EQUINE ENCEPHALOMYELITIS VIRUS ON CHICKEN EMBRYO CELLS GROWN IN VITRO AND ANALYSIS OF VIRUS YIELDS FROM SINGLE CELLS

1954 ◽  
Vol 99 (2) ◽  
pp. 183-199 ◽  
Author(s):  
R. Dulbecco ◽  
Marguerite Vogt
Keyword(s):  
Chicken Embryo ◽  
Cell Layer ◽  
Growth Curves ◽  
Virus Growth ◽  
Embryo Cells ◽  
Cell Layers ◽  
A Cell ◽  
One Step ◽  
Step Growth

The rate of adsorption of WEE virus onto chicken embryo cells in vitro was determined both on a cell layer and on a cell suspension. One-step growth curves were determined in cell suspensions and on cell layers. The latent period varied between 2 and 3½ hours; it was shorter on cell layers and decreased with higher multiplicity of infection. The shortest period is probably the real latent period. The growth curves of the virus showed an initial exponential rise and reached a maximal constant value after 6 to 8 hours. The maximum virus yield per cell varied between 200 and 1000 on the cell layer, and between 100 and 200 in suspended cells. The yield of single infected cells was determined. An analysis of the distributions of the individual yields obtained after various periods of virus growth led to two main conclusions: (1) that virus is released from the same cell over a long period of time; (2) that one phase of the intracellular virus growth is exponential.

Characterization of bacteriophages with a lytic effect on various Salmonella serotypes and Escherichia coli O157:H7

2011 ◽  
Vol 57 (12) ◽  
pp. 1042-1051 ◽  
Author(s):  
Osvaldo López-Cuevas ◽  
Nohelia Castro-del Campo ◽  
Josefina León-Félix ◽  
Arturo González-Robles ◽  
Cristóbal Chaidez
Keyword(s):  
Escherichia Coli ◽  
Burst Size ◽  
Growth Curves ◽  
Escherichia Coli O157 ◽  
Genetic Characteristics ◽  
E Coli ◽  
Lytic Effect ◽  
One Step ◽  
Salmonella Serotypes

Four phages isolated from cattle and poultry feces were analyzed for their ability to lyse Salmonella serotypes and Escherichia coli O157:H7. The phage one-step growth curves, morphology, and genetic characteristics were determined. All phages showed a lytic effect on various Salmonella serotypes and E. coli O157:H7, which lysed at least 70% of the 234 strains tested. The phages had latent periods ranging from 10 to 15 min and generation times of 30 to 45 min, while burst size fluctuated between 154 and 426 PFU/cell. Phages morphology showed isometric and elongated heads and rigid contractile tails, consistent with morphology of the Myoviridae family. Phages’ DNA dendrograms showed a distinctive RFLP when digested by HindIII and EcoRV, and SDS–PAGE profile showed distinctive proteins expression as well. In vitro phage challenge showed a total reduction of E. coli O157:H7, Salmonella Typhimurium and Saintpaul counts at 2 h, whereas for Salmonella Montevideo a reduction and retardation growth, at a multiplicity of infection (MOI) of 100, was observed; however, under a MOI of 10 000, no viable cells were detected after 4 h. The wide host ranges of these phages suggested they could be used for simultaneous biocontrol of some Salmonella serotypes and E. coli O157:H7.

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