Latent period, burst size and pH stability of some phages derived from S. virchow

1960 ◽  
Vol 146 (4) ◽  
pp. 310-314 ◽  
Author(s):  
T. Velaudapillai
Keyword(s):  
Latent Period ◽  
Burst Size ◽  
Ph Stability

scholarly journals Characterization of E coli phage isolated from sewage

2010 ◽  
Vol 9 (2) ◽  
pp. 45 ◽  
Author(s):  
G.A. Al-Mola, and I. H. Al-Yassari
Keyword(s):  
Statistical Analysis ◽  
Latent Period ◽  
Burst Size ◽  
Host Cells ◽  
Effect Of Temperature ◽  
Lytic Bacteriophage ◽  
Bacterial Cells ◽  
Dilution Factor ◽  
Countable Number ◽  
Phage Titre

Bacteriophage are viruses that infect bacterial cells. as with all viruses, phage are nonliving agents and thus require the use of the host‟s metabolic processes to replicate itself. in this study, the phage of interest are those that infect and lyses E. colt host cells. when phage are released from the ruptured host, distinct zones of clearing (plaques) form. the original E. colt host cells for this experiment came from a sample of raw sewage. in order to obtain the bacteriophage, a procedure of enrichment, isolation, dilution and seeding was followed, the presence of distinct plaques indicated that lytic bacteriophage had been successfully amplified, separated and grown.This study included determination of phage titre, latent period , rise period and the burst size of the phage and effect some of factor on phage titre such as (temperature, ether and chloroform) .for determination ofhage titre used series of dilutions(10-1, 10-2, 10-3, 10-4, 10-4, 10-6, 10-7, 10-8, 10-9) the dilution factor gave the best countable number of plaques is(103). this dilution factor was then used for all other experiments, the latent period , rise period and the burst size of the phage are determined by countable number of plaques and phage titre(titer: plaque-forming unit(p.f.u) during 10,20,30,40,50, and 60 minutes . it was (4.7x105 „ 5.3x105 and 6.0x105)during 1O,20and30minutes respectively in the latent period ,but it was (8.5x105 8.9x10‟ 9.3x105)during 40,50,and 60 minutes respectively in the rise period .then the burst size of the phage is counted by the ratio of the phage titer after rise period to that during the latent period it was(1.67).This study also included effect of temperature on phage titre the statistical analysis was significantly increase P<0.05 in phage titre at the temperature37 C° comparing with phage titre at the temperature 50 C° and phage titre at the temperature 65 C°. effects of ether and chloroform on number of plaques and phage titre during 5,10,15 ,20,25 ,30,35 and 40 minutes it was(0.7x105 , 0.3x105 , 0 , 0 , 0 , 0, 0 and 0) respectively in ether sensitivity, but the phage titre in chloroform sensitivity was completely inactivated by chloroform treatment, the statistical analysis (freedom degree ( 2,21 ) and F value=52.60 was high] significant increase (P<0.05) in phage titre in normal saline comparing with phage titre in ether and chloroform sensitivity

scholarly journals Host traits drive viral life histories across phytoplankton viruses

2017 ◽  
Author(s):  
Kyle F. Edwards ◽  
Grieg F. Steward
Keyword(s):  
Latent Period ◽  
Genome Size ◽  
Life Histories ◽  
Burst Size ◽  
Evolutionary Model ◽  
Viral Control ◽  
Ecosystem Impacts ◽  
Community Processes ◽  
Size Growth ◽  
Host Metabolism

AbstractViruses are integral to ecological and evolutionary processes, but we have a poor understanding of what drives variation in key traits across diverse viruses. For lytic viruses, burst size, latent period, and genome size are primary characteristics controlling host-virus dynamics. Burst size and latent period are analogous to organismal traits of fecundity and generation time, and genome size affects the size of the virion as well as viral control of host metabolism. Here we synthesize data on these traits for 75 strains of phytoplankton viruses, which play an important role in global biogeochemistry. We find that primary traits of the host (genome size, growth rate) are major ecological drivers, explaining 40-50% of variation in burst size and latent period. We analyze an eco-evolutionary model to explore mechanisms underlying these patterns. We find that burst size may be set by the host genomic resources available for viral construction, while latent period evolves to permit this maximal burst size, modulated by host metabolic rate. These results suggest that general mechanisms may underlie the evolution of diverse viruses, which will facilitate our understanding of viral community processes, ecosystem impacts, and coevolutionary dynamics.

scholarly journals THE INTRACELLULAR GROWTH OF BACTERIOPHAGES

1952 ◽  
Vol 35 (4) ◽  
pp. 657-667 ◽  
Author(s):  
Thomas F. Anderson ◽  
A. H. Doermann
Keyword(s):  
Latent Period ◽  
Burst Size ◽  
Host Cells ◽  
Intracellular Growth ◽  
Virus Particles ◽  
Active Virus

The growth of the virus T3 has been followed by breaking up the complexes it forms with host cells at various stages in their development and then assaying the debris for active virus particles. Two independent methods for breaking up cells were used: sonic vibration and lysis by the T6-cyanide method previously used for the study of the growth of T4. During the first half of the latent period both treatments, as well as cyanide alone, destroyed the capacity of the complexes for producing daughter virus particles. Furthermore, the infecting particles could not be recovered from them during the first half of the latent period. After the complexes had had 12 minutes of incubation at 30°C. both methods freed daughter virus particles from them in numbers which increased steadily with time until, near the end of the rise period, the normal burst size was reached. In general the agreement between the two yields is so good that one may conclude that both methods liberate quantitatively the mature daughter T3 particles which exist in the complexes before normal lysis occurs.

scholarly journals Isolation and Physiomorphological Characterization ofEscherichia coliO157:H7-Infecting Bacteriophages Recovered from Beef Cattle Operations

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Pushpinder Kaur Litt ◽  
Divya Jaroni
Keyword(s):  
Beef Cattle ◽  
Latent Period ◽  
Host Range ◽  
Cold Storage ◽  
Growth Parameters ◽  
Burst Size ◽  
Morphological Characteristics ◽  
Lytic Activity ◽  
E Coli ◽  
The Stability

Bacteriophages, recovered from beef cattle environment and specifically targetingEscherichia coliO157:H7, were examined for their physiological and morphological characteristics. Degree of bacterial lysis and host range of isolated bacteriophages was determined against 55 isolates ofE. coliO157:H7. Morphology of phages was examined under transmission electron microscope. Phage growth parameters, particularly rate of adsorption, rise period, latent period, and burst size were also determined. The stability of isolated phages was tested at acidic and alkaline pH, at high temperatures, and in cold storage. A total of 7 phages were isolated which showed lytic activity against 50 out of 55 isolates ofE. coliO157:H7. Based on the morphology, phages were classified into Myoviridae or Siphoviridae family. Phages had a rise period between 19 and 40 min, a short latent period between 12 and 30 min, and a large burst size (89–631 virions per infected cell), indicating high lytic activity. Phages remained stable for 24 h at a wide pH (1–11) and temperature range (40–60°C) and for 90 d in cold storage. Characterization of bacteriophages, with a diverse host range ofE. coliO157:H7, could aid in the development of effective biocontrol strategies for this pathogen in the food industry.

Partial characterization of a cubic Bacillus phage

1978 ◽  
Vol 24 (8) ◽  
pp. 986-993 ◽  
Author(s):  
H.-W. Ackermann ◽  
R. Roy ◽  
M. Martin ◽  
M. R. V. Murthy ◽  
W. A. Smirnoff
Keyword(s):  
Drug Resistance ◽  
Nucleic Acid ◽  
Latent Period ◽  
Burst Size ◽  
Partial Characterization ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Resistance Plasmids ◽  
Bacillus Phage

Phage Bam35 is an icosahedron of about 63 nm in diameter. It has a double capsid with spikes at the vertices, and a tail which seems to appear upon nucleic acid ejection. The phage contains DNA and, probably, lipids which seem to be located in the inner coat. The phage is Bacillus-specific, UV- and lipase-resistant, and sensitive to heat, chloroform, and ether. The latent period is 50 min and the burst size is 39. Phage Bam35 belongs to a new virus group which includes a phage of B. anthracis and four phages of gram-negative bacteria harboring drug-resistance plasmids.

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.

scholarly journals Characterization of Bacteriophage against Enterococcus faecium Resistant to Vancomycin Isolated from Chicken Skin

2019 ◽  
pp. 1-14
Author(s):  
Hazzierah Syaffieqah An Nadiah Azlan ◽  
Muhajir Hamid ◽  
Adelene Ai-Lian Song
Keyword(s):  
Latent Period ◽  
Growth Kinetics ◽  
Enterococcus Faecium ◽  
Burst Size ◽  
Single Step ◽  
Vancomycin Resistant Enterococcus ◽  
Chicken Skin ◽  
Step Growth ◽  
Vancomycin Resistant ◽  
Faecium Strain

Aims: To characterize bacteriophages with strong in vitro lytic activity against vancomycin resistant Enterococcus faecium before testing on the chicken skin for their efficacy. Study Design: An experimental was carried out to characterize two isolated bacteriophages against Enterococcus faecium and test for their efficacy on chicken skin. Study Place: The study was carried out in Laboratory of Vaccine and Immunotherapeutics, Institue of Bioscience, Universiti Putra Malaysia in Selangor, which is the most populous state in Malaysia. Methodology: Two host specific lytic phages against vancomycin resistant Enterococcus faecium strain FM8, designated as FM8-P1 and FM8-P2 were physiological characterized. This includes determination of their adsorption rate, multiplicity of infection, and single step growth kinetics. The optimum pH and temperature for both bacteriophages activity were also determined before tested on chicken skin at 4°C and 25°C, which represent chiller and room temperature in poultry production line. Results: Based on the result of single-step growth kinetics, the latent period of FM8-P1 was 35 min with a burst size of 460 particles per infected cells, while FM8-P2 has a shorter latent period (20 min) but a smaller burst size of 60 particles. The highest adsorption rate for FM8-P1 was 83% and FM8-P2 was 90% at 2 min and 4 min respectively. Both bacteriophages also exihibited a wide range of pH and temperature for their activity. Conclusion: The specificity, lytic activity and stability of FM8-P1 and FM8-P2 emphasized their potential in effectively eliminating the vancomycin resistant Enterococcus faecium strain FM8. However, further works are required to validate their in situ reliability.

scholarly journals Experimental Examination of Bacteriophage Latent-Period Evolution as a Response to Bacterial Availability

2003 ◽  
Vol 69 (12) ◽  
pp. 7499-7506 ◽  
Author(s):  
Stephen T. Abedon ◽  
Paul Hyman ◽  
Cameron Thomas
Keyword(s):  
Population Growth ◽  
Latent Period ◽  
Generation Time ◽  
Burst Size ◽  
Lytic Bacteriophage ◽  
Wild Type ◽  
Experimental Examination ◽  
Trade Off ◽  
Culture Growth ◽  
Mutant Frequency

ABSTRACT For obligately lytic bacteriophage (phage) a trade-off exists between fecundity (burst size) and latent period (a component of generation time). This trade-off occurs because release of phage progeny from infected bacteria coincides with destruction of the machinery necessary to produce more phage progeny. Here we employ phage mutants to explore issues of phage latent-period evolution as a function of the density of phage-susceptible bacteria. Theory suggests that higher bacterial densities should select for shorter phage latent periods. Consistently, we have found that higher host densities (≥∼107 bacteria/ml) can enrich stocks of phage RB69 for variants that display shorter latent periods than the wild type. One such variant, dubbed sta5, displays a latent period that is ∼70 to 80% of that of the wild type—which is nearly as short as the RB69 eclipse period—and which has a corresponding burst size that is ∼30% of that of the wild type. We show that at higher host densities (≥∼107 bacteria/ml) the sta5 phage can outcompete the RB69 wild type, though only under conditions of direct (same-culture) competition. We interpret this advantage as corresponding to slightly faster sta5 population growth, resulting in multifold increases in mutant frequency during same-culture growth. The sta5 advantage is lost, however, given indirect (different-culture) competition between the wild type and mutant or given same-culture competition but at lower densities of phage-susceptible bacteria (≤∼106 bacteria/ml). From these observations we suggest that phage displaying very short latent periods may be viewed as specialists for propagation when bacteria within cultures are highly prevalent and transmission between cultures is easily accomplished.

scholarly journals Bacteriophage T4 resistance to lysis-inhibition collapse

1999 ◽  
Vol 74 (1) ◽  
pp. 1-11 ◽  
Author(s):  
STEPHEN T. ABEDON
Keyword(s):  
Latent Period ◽  
Burst Size ◽  
Bacteriophage T4 ◽  
Size Increase ◽  
Wild Type ◽  
Lysis Inhibition ◽  
T4 Bacteriophage ◽  
Infected Cells

Lysis inhibition is a mechanism of latent-period extension and burst-size increase that is induced by the T4 bacteriophage adsorption of T4-infected cells. Mutants of T4 genes imm, sp and 5 (specifically the ts1 mutant of 5) display some lysis inhibition. However, these mutants experience lysis-inhibition collapse, the lysis of lysis-inhibited cells, earlier than wild-type-infected cells (i.e. their collapse occurs prematurely). Lysis from without is a lysis induced by excessive T4 adsorption. Gp5 is an inducer of lysis from without while gpimm and gpsp effect resistance to lysis from without. This paper shows that interfering with the adsorption of phages to imm-, sp- or 5ts1-mutant-infected cells, in a variety of contexts, inhibits premature lysis-inhibition collapse. From these data it is inferred that wild-type T4-infected cells display resistance to lysis-inhibition collapse by a mechanism resembling resistance to lysis from without.

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