scholarly journals Fitness benefits of low infectivity in a spatially structured population of bacteriophages

2014 ◽  
Vol 281 (1774) ◽  
pp. 20132563 ◽  
Author(s):  
Pavitra Roychoudhury ◽  
Neelima Shrestha ◽  
Valorie R. Wiss ◽  
Stephen M. Krone

For a parasite evolving in a spatially structured environment, an evolutionarily advantageous strategy may be to reduce its transmission rate or infectivity. We demonstrate this empirically using bacteriophage (phage) from an evolution experiment where spatial structure was maintained over 550 phage generations on agar plates. We found that a single substitution in the major capsid protein led to slower adsorption of phage to host cells with no change in lysis time or burst size. Plaques formed by phage isolates containing this mutation were not only larger but also contained more phage per unit area. Using a spatially explicit, individual-based model, we showed that when there is a trade-off between adsorption and diffusion (i.e. less ‘sticky’ phage diffuse further), slow adsorption can maximize plaque size, plaque density and overall productivity. These findings suggest that less infective pathogens may have an advantage in spatially structured populations, even when well-mixed models predict that they will not.

2007 ◽  
Vol 89 (1) ◽  
pp. 7-18 ◽  
Author(s):  
JAIME COMBADÃO ◽  
PAULO R. A. CAMPOS ◽  
FRANCISCO DIONISIO ◽  
ISABEL GORDO

Muller's ratchet is an evolutionary process that has been implicated in the extinction of asexual species, the evolution of non-recombining genomes, such as the mitochondria, the degeneration of the Y chromosome, and the evolution of sex and recombination. Here we study the speed of Muller's ratchet in a spatially structured population which is subdivided into many small populations (demes) connected by migration, and distributed on a graph. We studied different types of networks: regular networks (similar to the stepping-stone model), small-world networks and completely random graphs. We show that at the onset of the small-world network – which is characterized by high local connectivity among the demes but low average path length – the speed of the ratchet starts to decrease dramatically. This result is independent of the number of demes considered, but is more pronounced the larger the network and the stronger the deleterious effect of mutations. Furthermore, although the ratchet slows down with increasing migration between demes, the observed decrease in speed is smaller in the stepping-stone model than in small-world networks. As migration rate increases, the structured populations approach, but never reach, the result in the corresponding panmictic population with the same number of individuals. Since small-world networks have been shown to describe well the real contact networks among people, we discuss our results in the light of the evolution of microbes and disease epidemics.


2018 ◽  
Vol 12 (2) ◽  
pp. e0006234 ◽  
Author(s):  
Jorge Velázquez-Castro ◽  
Andrés Anzo-Hernández ◽  
Beatriz Bonilla-Capilla ◽  
Moisés Soto-Bajo ◽  
Andrés Fraguela-Collar

Author(s):  
Anna Clara Balbina Silva ◽  
Afonso Pelli

Compreender os mecanismos que regulam a dinâmica das populações espacialmente estruturadas é um desafio crítico para os ecólogos e gestores de conservação. A dinâmica de populações é um ramo da ecologia que estuda as populações como sistema em atividades, relacionando as influências ambientais com a distribuição e abundância dos indivíduos e suas interações com o ambiente. O presente artigo é uma revisão bibliográfica, com o objetivo de identificar produções científicas relevantes sobre dinâmica populacional. Para isso, foram utilizados periódicos revisados por pares, na base de Periódicos Capes. A pesquisa foi realizada em junho de 2019, utilizando-se as palavras-chave para título contendo: "population dynamics" e no assunto “ecology”, a partir de 2014, quando o texto completo estava disponível. Foram considerados como critérios de exclusão os artigos publicados antes de 2014. Após a leitura dos títulos dos artigos, foram selecionados 34 artigos que foram lidos na íntegra. Em livros disponíveis no acervo da biblioteca da Universidade Federal do Triângulo Mineiro, foram selecionados quatro livros no tema dinâmica populacional. O referencial teórico aborda os aspectos da dinâmica de populações, tabela de vida, formas de crescimento e interações populacionais. Ressalta-se a necessidade de novos estudos que ainda possuem lacunas, que venha complementar e contribuir para o conhecimento de organismos que faltam ou ainda não possuem registros de estudos. Palavras-chave: Taxas de Natalidade e Mortalidade. Atributos Populacionais. Dispersão. AbstractUnderstanding the mechanisms that regulate the dynamics of spatially structured populations is a critical challenge for ecologists and conservation managers. Population dynamics is a branch of ecology that studies populations as a system in activities, relating environmental influences to the individuals’ distribution and abundance and their interactions with the environment. This article is a bibliographic review, aiming to identify relevant scientific productions about population dynamics. Thus. peer-reviewed journals were used in the Capes Periodicals base, the research was conducted in June 2019, using the keywords for title containing "population dynamics" and in the subject "ecology", from 2014, when the full text was available. Exclusion criteria were: articles published before 2014, after reading the article titles, 34 articles were selected that met the initially proposed criteria and were read in full. In books available in the library collection of the Federal University of Triângulo Mineiro, with a search for the dynamic population theme, 4 books were used. The theoretical framework addresses the aspects of population dynamics, life table, forms of growth and population interactions. It is emphasized  the need for further studies that still have gaps, which will complement and contribute to the knowledge of organisms that are missing or do not have study records. Keywords: Birth and Mortality Rates. Population Attributes. Dispersion.


2020 ◽  
pp. 105-124
Author(s):  
Michael J. Fogarty ◽  
Jeremy S. Collie

Aquatic populations are patchily distributed. The full implications of this statement for the dynamics of these populations depend very strongly on movement and dispersal patterns. The characteristically heterogeneous distribution of exploited aquatic species is of course essential to harvesting strategies employed by fishers. It can also present important challenges to management when species distributions contract to core habitat areas and these concentrations can be readily located and exploited. The types of models described in this chapter, including metapopulation models, provide an initial framework for considering the dynamics of spatially structured populations. Dispersal can provide a stabilizing force by providing a subsidy or rescue effect for depleted populations. Realistic representation of spatial processes in models of aquatic populations is an evolving art. Quantifying movement and connectivity of aquatic species entails special challenges. Spatially explicit models should account for exchange among subpopulations in relation to their size, distance, and degree of separation.


2014 ◽  
Vol 272 ◽  
pp. 198-207 ◽  
Author(s):  
Charles L. Nunn ◽  
Peter H. Thrall ◽  
Peter M. Kappeler

2017 ◽  
Vol 8 (1) ◽  
pp. 493-508 ◽  
Author(s):  
Christine Sample ◽  
John M. Fryxell ◽  
Joanna A. Bieri ◽  
Paula Federico ◽  
Julia E. Earl ◽  
...  

2001 ◽  
Vol 63 (4) ◽  
Author(s):  
Joshua E. S. Socolar ◽  
Shane Richards ◽  
William G. Wilson

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