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.

Genome size in cyclopoid copepods (Copepoda: Cyclopoida): chromatin diminution as a hypothesized mechanism of evolutionary constraint

2021 ◽  
Vol 41 (3) ◽  
Author(s):  
Emilly Schutt ◽  
Maria Hołyńska ◽  
Grace A Wyngaard
Keyword(s):  
Genome Size ◽  
Life Histories ◽  
Nuclear Dna ◽  
Cell Lineage ◽  
Fundamental Property ◽  
Nuclear Dna Content ◽  
Evolutionary Constraint ◽  
Chromatin Diminution ◽  
Somatic Genome ◽  
Copepoda Cyclopoida

Abstract Genome size is a fundamental property of organisms that impacts their molecular evolution and life histories. The hypothesis that somatic genome sizes in copepods in the order Cyclopoida are small and evolutionary constrained relative to those in the order Calanoida was proposed 15 years ago. Since then, the number of estimates has almost doubled and the taxon sampling has broadened. Here we add 14 new estimates from eight genera of freshwater cyclopoids that vary from 0.2 to 6.6 pg of DNA per nucleus in the soma; all except one are 2.0 pg DNA per nucleus or smaller. This new sample adds to the pattern of genome size in copepods and is remarkably similar to the distribution on which the original hypothesis was based, as well as those of subsequently published estimates. Embryonic chromatin diminution, during which large portions of DNA are excised from the presomatic cell lineage, is reported in Paracyclops affinis (G.O. Sars, 1863). This diminution results in a somatic genome that is one half the size of the germline genome. When the sizes of the germline genomes carried in presomatic cells of cyclopoid species that possess chromatin diminution are considered, the prediminuted germline genome sizes of cyclopoid embryos overlap with the distribution of calanoid somatic genome sizes, supporting the hypothesis that chromatin diminution has functioned as a mechanism to constrain somatic nuclear DNA content in cyclopoid copepods. Geographically based variation in genome size among populations is also reviewed.

scholarly journals Genome Size Evolution and Dynamics in Iris, with Special Focus on the Section Oncocyclus

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1687
Author(s):  
Nour Abdel Samad ◽  
Oriane Hidalgo ◽  
Elie Saliba ◽  
Sonja Siljak-Yakovlev ◽  
Kit Strange ◽  
...  
Keyword(s):  
Genome Size ◽  
Eastern Mediterranean ◽  
Eastern Mediterranean Region ◽  
Evolutionary Model ◽  
Distinct Species ◽  
Special Focus ◽  
Plant Groups ◽  
Genome Size Evolution ◽  
Size Evolution ◽  
Phylogenetic Framework

Insights into genome size dynamics and its evolutionary impact remain limited by the lack of data for many plant groups. One of these is the genus Iris, of which only 53 out of c. 260 species have available genome sizes. In this study, we estimated the C-values for 41 species and subspecies of Iris mainly from the Eastern Mediterranean region. We constructed a phylogenetic framework to shed light on the distribution of genome sizes across subgenera and sections of Iris. Finally, we tested evolutionary models to explore the mode and tempo of genome size evolution during the radiation of section Oncocyclus. Iris as a whole displayed a great variety of C-values; however, they were unequally distributed across the subgenera and sections, suggesting that lineage-specific patterns of genome size diversification have taken place within the genus. The evolutionary model that best fitted our data was the speciational model, as changes in genome size appeared to be mainly associated with speciation events. These results suggest that genome size dynamics may have contributed to the radiation of Oncocyclus irises. In addition, our phylogenetic analysis provided evidence that supports the segregation of the Lebanese population currently attributed to Iris persica as a distinct species.

scholarly journals Bioprospecting Staphylococcus Phages with Therapeutic and Bio-Control Potential

Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 133 ◽  
Author(s):  
Joseph M. Ochieng’ Oduor ◽  
Ermir Kadija ◽  
Atunga Nyachieo ◽  
Marianne W. Mureithi ◽  
Mikael Skurnik
Keyword(s):  
Phage Particle ◽  
Burst Size ◽  
Radiation Energy ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Rna Ligase ◽  
The Public ◽  
Ph Range ◽  
Host Metabolism

Emergence of antibiotic-resistant bacteria is a serious threat to the public health. This is also true for Staphylococcus aureus and other staphylococci. Staphylococcus phages Stab20, Stab21, Stab22, and Stab23, were isolated in Albania. Based on genomic and phylogenetic analysis, they were classified to genus Kayvirus of the subfamily Twortvirinae. In this work, we describe the in-depth characterization of the phages that electron microscopy confirmed to be myoviruses. These phages showed tolerance to pH range of 5.4 to 9.4, to maximum UV radiation energy of 25 µJ/cm2, to temperatures up to 45 °C, and to ethanol concentrations up to 25%, and complete resistance to chloroform. The adsorption rate constants of the phages ranged between 1.0 × 10−9 mL/min and 4.7 × 10−9 mL/min, and the burst size was from 42 to 130 plaque-forming units. The phages Stab20, 21, 22, and 23, originally isolated using Staphylococcus xylosus as a host, demonstrated varied host ranges among different Staphylococcus strains suggesting that they could be included in cocktail formulations for therapeutic or bio-control purpose. Phage particle proteomes, consisting on average of ca 60–70 gene products, revealed, in addition to straight-forward structural proteins, also the presence of enzymes such DNA polymerase, helicases, recombinases, exonucleases, and RNA ligase polymer. They are likely to be injected into the bacteria along with the genomic DNA to take over the host metabolism as soon as possible after infection.

scholarly journals Insulin-like growth factor-1 is associated with life-history variation across Mammalia

2014 ◽  
Vol 281 (1782) ◽  
pp. 20132458 ◽  
Author(s):  
Eli M. Swanson ◽  
Ben Dantzer
Keyword(s):  
Life History ◽  
Growth Factor ◽  
Life Histories ◽  
Life History Traits ◽  
Mammalian Species ◽  
Insulin Like Growth Factor ◽  
Life History Variation ◽  
Time Period ◽  
Path Analyses ◽  
Size Growth

Despite the diversity of mammalian life histories, persistent patterns of covariation have been identified, such as the ‘fast–slow’ axis of life-history covariation. Smaller species generally exhibit ‘faster’ life histories, developing and reproducing rapidly, but dying young. Hormonal mechanisms with pleiotropic effects may mediate such broad patterns of life-history variation. Insulin-like growth factor 1 (IGF-1) is one such mechanism because heightened IGF-1 activity is related to traits associated with faster life histories, such as increased growth and reproduction, but decreased lifespan. Using comparative methods, we show that among 41 mammalian species, increased plasma IGF-1 concentrations are associated with fast life histories and altricial reproductive patterns. Interspecific path analyses show that the effects of IGF-1 on these broad patterns of life-history variation are through its direct effects on some individual life-history traits (adult body size, growth rate, basal metabolic rate) and through its indirect effects on the remaining life-history traits. Our results suggest that the role of IGF-1 as a mechanism mediating life-history variation is conserved over the evolutionary time period defining mammalian diversification, that hormone–trait linkages can evolve as a unit, and that suites of life-history traits could be adjusted in response to selection through changes in plasma IGF-1.

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 THE ECOLOGICAL CONSEQUENCES OF HABITAT AND MICROHABITAT USE IN LIZARDS:

2001 ◽  
pp. 1-28 ◽  
Author(s):  
Geoffrey R. Smith ◽  
Royce E. Ballinger
Keyword(s):  
Habitat Use ◽  
Life Histories ◽  
Thermal Characteristics ◽  
Individual Performance ◽  
Microhabitat Use ◽  
Ecological Consequences ◽  
Habitat Changes ◽  
Physiological Processes ◽  
Community Processes ◽  
The Face

We review the ecological consequences of habitat and microhabitat use in lizards. Different habitats have different biotic and abiotic properties and thus are likely to have different consequences for the lizards that occur in them. Individual performance and life histories are influenced by habitat use, particularly when habitats differ in thermal characteristics that may influence physiological processes or constrain activity. We know relatively little about how the effects of habitat use on individual performance translate into population dynamics. We do know that the ability of lizards to use particular habitats can influence the persistence of populations in the face of habitat changes. Community-level processes (e.g., competition) and community structure (e.g., diversity) can be influenced by habitat use in lizards, often by habitat use facilitating co-existence of two or more potentially competing species. We know relatively little about how other community processes, such as predation and parasitism, are influenced by habitat use.

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.

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