Estimation of the average burst size of ?x174am3, cs70 for use in mutation assays with transgenic mice

2001 ◽  
Vol 37 (4) ◽  
pp. 356-360 ◽  
Author(s):  
Robert R. Delongchamp ◽  
Carrie R. Valentine ◽  
Heinrich V. Malling
Keyword(s):  
Transgenic Mice ◽  
Burst Size ◽  
Average Burst Size

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 Identification of Cyanophage Ma-LBP and Infection of the Cyanobacterium Microcystis aeruginosa from an Australian Subtropical Lake by the Virus

2005 ◽  
Vol 71 (2) ◽  
pp. 629-635 ◽  
Author(s):  
Stephen Tucker ◽  
Peter Pollard
Keyword(s):  
Host Cell ◽  
Microcystis Aeruginosa ◽  
Burst Size ◽  
Host Community ◽  
Cyanobacterial Blooms ◽  
Viral Population ◽  
Transmission Electron ◽  
Viral Communities ◽  
Average Burst Size ◽  
Physical And Chemical

ABSTRACT Viruses can control the structure of bacterial communities in aquatic environments. The aim of this project was to determine if cyanophages (viruses specific to cyanobacteria) could exert a controlling influence on the abundance of the potentially toxic cyanobacterium Microcystis aeruginosa (host). M. aeruginosa was isolated, cultured, and characterized from a subtropical monomictic lake—Lake Baroon, Sunshine Coast, Queensland, Australia. The viral communities in the lake were separated from cyanobacterial grazers by filtration and chloroform washing. The natural lake viral cocktail was incubated with the M. aeruginosa host growing under optimal light and nutrient conditions. The specific growth rate of the host was 0.023 h−1; generation time, 30.2 h. Within 6 days, the host abundance decreased by 95%. The density of the cyanophage was positively correlated with the rate of M. aeruginosa cell lysis (r 2 = 0.95). The cyanophage replication time was 11.2 h, with an average burst size of 28 viral particles per host cell. However, in 3 weeks, the cultured host community recovered, possibly because the host developed resistance (immunity) to the cyanophage. The multiplicity of infection was determined to be 2,890 virus-like particles/cultured host cell, using an undiluted lake viral population. Transmission electron microscopy showed that two types of virus were likely controlling the host cyanobacterial abundance. Both viruses displayed T7-like morphology and belonged to the Podoviridiae group (short tails) of viruses that we called cyanophage Ma-LBP. In Lake Baroon, the number of the cyanophage Ma-LBP was 5.6 × 104 cyanophage · ml−1, representing 0.23% of the natural viral population of 2.46 × 107 · ml−1. Our results showed that this cyanophage could be a major natural control mechanism of M. aeruginosa abundance in aquatic ecosystems like Lake Baroon. Future studies of potentially toxic cyanobacterial blooms need to consider factors that influence cyanophage attachment, infectivity, and lysis of their host alongside the physical and chemical parameters that drive cyanobacterial growth and production.

Properties of psychrophilic bacteriophage specific for Micrococcus cryophilus

1971 ◽  
Vol 17 (2) ◽  
pp. 157-160 ◽  
Author(s):  
Charles F. Kulpa Jr. ◽  
R. H. Olsen
Keyword(s):  
Host Range ◽  
Burst Size ◽  
Gram Positive ◽  
First Report ◽  
Average Burst Size

A bacteriophage infective for the obligate psychrophile, Micrococcus cryophilus, was isolated from sewage. The host range is limited to this species. Phage and host DNA are similar in G–C content. The bacteriophage has an average burst size of 290 at 20 °C and 50 at 3.5 °C. The phage is thermosensitive, being 99.9% inactivated in 5 min at 45 °C. This is the first report of the isolation of bacteriophage infective for gram-positive psychrophiles.

INFLUENCE OF SELECTED HERBICIDES IN PHAGES OF SOME SOIL BACTERIA

1982 ◽  
Vol 62 (1) ◽  
pp. 217-220 ◽  
Author(s):  
E. B. ROSLYCKY
Keyword(s):  
Latent Period ◽  
Soil Bacteria ◽  
Rhizobium Meliloti ◽  
Burst Size ◽  
Lytic Activity ◽  
Agrobacterium Radiobacter ◽  
Host System ◽  
Average Burst Size ◽  
Homologous Antiserum ◽  
Particle Attachment

Various concentrations of paraquat, atrazine, simazine, linuron, diuron, and paraquat in combinations with each including simazine + diuron, and terbacil alone, did not inhibit lytic activity of four bacteriophages of Agrobacterium radiobacter, three bacteriophages of Rhizobium meliloti, three bacteriophages of R. trifolii, or two bacteriophages of Streptomyces chrysomallus. Generally, the herbicides had no effect on the neutralization of radiobacterphage PR-1001 with its homologous antiserum, the length of the latent period, the percent adsorption or the average burst size. In contrast, paraquat concentrations from 20 to 400 μg∙mL−1 gradually reduced the adsorption from 38 to 21% and the average burst size from 67 to 9 in the PR-1001:R-1001 phage: host system. The same concentrations, however, showed no effect on the particle attachment or the length of the latent period.

Isolation and characterization of wetland VSW-3, a novel lytic cold-active bacteriophage of Pseudomonas fluorescens

2017 ◽  
Vol 63 (2) ◽  
pp. 110-118 ◽  
Author(s):  
Kunhao Qin ◽  
Xiuling Ji ◽  
Chunjing Zhang ◽  
Yafang Ding ◽  
Anxiu Kuang ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Burst Size ◽  
Isolation And Characterization ◽  
A Genome ◽  
Cold Active ◽  
Average Burst Size ◽  
20 Nm ◽  
High Degree ◽  
Thermal Stability Of

Wetlands are often called the “kidneys of the Earth” and contribute substantially to environmental improvement. Pseudomonas fluorescens is a major contaminant of milk products and causes the spoilage of refrigerated foods and fresh poultry. In this study, we isolated and characterized a lytic cold-active bacteriophage named VSW-3 together with P. fluorescens SW-3 cells from the Napahai wetland in China. Electron microscopy showed that VSW-3 had an icosahedral head (56 nm) and a tapering tail (20 nm × 12 nm) and a genome size of approximate 40 kb. On the basis of the top-scoring hits in the BLASTP analysis, VSW-3 showed a high degree of module similarity to the Pseudomonas phages Andromeda and Bf7. The latent and burst periods were 45 and 20 min, respectively, with an average burst size of 90 phage particles per infected cell. The pH and thermal stability of VSW-3 were also explored. The optimal pH was found to be 7.0 and the activity decreased rapidly when the temperature exceeded 60 °C. VSW-3 is a cold-active bacteriophage, hence, it is important to research its ability to prevent product contamination caused by P. fluorescens and to characterize its relationship with its host P. fluorescens in the future.

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.

scholarly journals Discrete Distributional Differential Expression (D3E) - A Tool for Gene Expression Analysis of Single-cell RNA-seq Data

2015 ◽  
Author(s):  
Mihails Delmans ◽  
Martin Hemberg
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Burst Size ◽  
Synthetic Data ◽  
Driving Mechanism ◽  
Rna Seq ◽  
Experimental Conditions ◽  
Distributional Method ◽  
Average Burst Size ◽  
Differential Gene

The advent of high throughput RNA-seq at the single-cell level has opened up new opportunities to elucidate the heterogeneity of gene expression. One of the most widespread applications of RNA-seq is to identify genes which are differentially expressed (DE) between two experimental conditions. Here, we present a discrete, distributional method for differential gene expression (D3E), a novel algorithm specifically designed for single-cell RNA-seq data. We use synthetic data to evaluate D3E, demonstrating that it can detect changes in expression, even when the mean level remains unchanged. D3E is based on an analytically tractable stochastic model, and thus it provides additional biological insights by quantifying biologically meaningful properties, such as the average burst size and frequency. We use D3E to investigate experimental data, and with the help of the underlying model, we directly test hypotheses about the driving mechanism behind changes in gene expression.

scholarly journals Host-Controlled Modification of Rhizobium Bacteriophage

1965 ◽  
Vol 18 (2) ◽  
pp. 333 ◽  
Author(s):  
EA Schwinghamer
Keyword(s):  
Host Specificity ◽  
Phenotypic Variation ◽  
Small Proportion ◽  
Burst Size ◽  
Specific Form ◽  
Host System ◽  
One Step ◽  
Average Burst Size ◽  
In Cells

Host-controlled phenotypic variation of host specificity was observed with two rhizobiophage strains, 0Ll and 0L5, following growth on six strains of Rhizobium legumino8arum and R. trifolii. The six hosts could be assigned to four groups, each group representing a different pattern of host specificity. Initial adaptation of 0L5 to hosts L2, L7, and L25 appeared to involve mutation, although replication in cells of these hosts generally involved additional phenotypic restriction. Restricted and unrestricted forms of a phage did not differ significantly in their ability to adsorb to several hosts. One-step analysis of the L25-specific form of 0L5 grown in L25 cells indicated a low average burst size of approximately one unrestricted plaque-forming unit in a small proportion of cells which were able to produce infective centres on L4. One-cycle analysis of L4-specific 0L5 modified by growth in L25 confirmed the phenotypic nature of phage variation in this phage-host system, and indicated that specificity for L4 was not replicated in L25.

scholarly journals Isolation and Characterization of an Aeromonas punctata Bacteriophage

2015 ◽  
Vol 9 (1) ◽  
pp. 185-187 ◽  
Author(s):  
Cheng Kai ◽  
Zhang Denglan ◽  
Deng Jingxuan ◽  
Zhao Yijun
Keyword(s):  
Restriction Enzyme ◽  
Burst Size ◽  
Wuhan City ◽  
Isolation And Characterization ◽  
Double Stranded Dna ◽  
East Lake ◽  
Average Burst Size ◽  
Enzyme Pattern ◽  
Restriction Enzyme Pattern

AnAeromonas punctatabacteriophage, named as DH1, was isolated from East Lake, Wuhan city, China. Morphologically, phage DH1 showed a typicalMyoviridaestructure consisting of an isometric head (50 nm in diameter) and a visible tail. The bacteriophage had a latent period of about 90 minutes and an average burst size of about 125 PFU•Cell-1. Restriction enzyme pattern of the bacteriophage’s genome showed that the genome is a double-stranded DNA and about 34kb in size. The sequenced genomic fragments showed highly similarities to gp04 and gp16 sequence of otherMyoviridaebacteriophages at protein level.

scholarly journals Characterization and complete genome sequence of Privateer, a highly prolate Proteus mirabilis podophage

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10645
Author(s):  
James E. Corban ◽  
Jolene Ramsey
Keyword(s):  
Proteus Mirabilis ◽  
Burst Size ◽  
Treatment Plant ◽  
Structural Proteins ◽  
Replication Proteins ◽  
Protein Coding ◽  
Translational Frameshift ◽  
Genes Encoding ◽  
Average Burst Size ◽  
Tract Infections

The Gram-negative bacterium Proteus mirabilis causes a large proportion of catheter-associated urinary tract infections, which are among the world’s most common nosocomial infections. Here, we characterize P. mirabilis bacteriophage Privateer, a prolate podophage of the C3 morphotype isolated from Texas wastewater treatment plant activated sludge. Basic characterization assays demonstrated Privateer has a latent period of ~40 min and average burst size around 140. In the 90.7 kb Privateer genome, 43 functions were assigned for the 144 predicted protein-coding genes. Genes encoding DNA replication proteins, DNA modification proteins, four tRNAs, lysis proteins, and structural proteins were identified. Cesium-gradient purified Privateer particles analyzed via LC-MS/MS verified the presence of several predicted structural proteins, including a longer, minor capsid protein apparently produced by translational frameshift. Comparative analysis demonstrated Privateer shares 83% nucleotide similarity with Cronobacter phage vB_CsaP_009, but low nucleotide similarity with other known phages. Predicted structural proteins in Privateer appear to have evolutionary relationships with other prolate podophages, in particular the Kuraviruses

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