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1.
Parasit Vectors ; 12(1): 473, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31604471

RESUMO

BACKGROUND: A considerable amount of evidence has favored ecological host-fitting, rather than coevolution, as the main mechanism responsible for trypanosome divergence. Nevertheless, beyond the study of human pathogenic trypanosomes, the genetic basis of host specificity among trypanosomes isolated from forest-inhabiting hosts remains largely unknown. METHODS: To test possible scenarios on ecological host-fitting and coevolution, we combined a host capture recapture strategy with parasite genetic data and studied the genetic variation, population dynamics and phylogenetic relationships of Trypanosoma terrestris, a recently described trypanosome species isolated from lowland tapirs in the Brazilian Pantanal and Atlantic Forest biomes. RESULTS: We made inferences of T. terrestris population structure at three possible sources of genetic variation: geography, tapir hosts and 'putative' vectors. We found evidence of a bottleneck affecting the contemporary patterns of parasite genetic structure, resulting in little genetic diversity and no evidence of genetic structure among hosts or biomes. Despite this, a strongly divergent haplotype was recorded at a microgeographical scale in the landscape of Nhecolândia in the Pantanal. However, although tapirs are promoting the dispersion of the parasites through the landscape, neither geographical barriers nor tapir hosts were involved in the isolation of this haplotype. Taken together, these findings suggest that either host-switching promoted by putative vectors or declining tapir population densities are influencing the current parasite population dynamics and genetic structure. Similarly, phylogenetic analyses revealed that T. terrestris is strongly linked to the evolutionary history of its perissodactyl hosts, suggesting a coevolving scenario between Perissodactyla and their trypanosomes. Additionally, T. terrestris and T. grayi are closely related, further indicating that host-switching is a common feature promoting trypanosome evolution. CONCLUSIONS: This study provides two lines of evidence, both micro- and macroevolutionary, suggesting that both host-switching by ecological fitting and coevolution are two important and non-mutually-exclusive processes driving the evolution of trypanosomes. In line with other parasite systems, our results support that even in the face of host specialization and coevolution, host-switching may be common and is an important determinant of parasite diversification.


Assuntos
Perissodáctilos/parasitologia , Trypanosoma/classificação , Jacarés e Crocodilos/parasitologia , Animais , Teorema de Bayes , Coevolução Biológica , Análise por Conglomerados , Fenômenos Ecológicos e Ambientais , Ecossistema , Variação Genética , Genética Populacional , Interações Hospedeiro-Parasita , Filogenia , Dinâmica Populacional , Trypanosoma/genética , Trypanosoma/crescimento & desenvolvimento
2.
Nat Commun ; 10(1): 4301, 2019 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-31541093

RESUMO

Generalist bacterial predators are likely to strongly shape many important ecological and evolutionary features of microbial communities, for example by altering the character and pace of molecular evolution, but investigations of such effects are scarce. Here we report how predator-prey interactions alter the evolution of fitness, genomes and phenotypic diversity in coevolving bacterial communities composed of Myxococcus xanthus as predator and Escherichia coli as prey, relative to single-species controls. We show evidence of reciprocal adaptation and demonstrate accelerated genomic evolution specific to coevolving communities, including the rapid appearance of mutator genotypes. Strong parallel evolution unique to the predator-prey communities occurs in both parties, with predators driving adaptation at two prey traits associated with virulence in bacterial pathogens-mucoidy and the outer-membrane protease OmpT. Our results suggest that generalist predatory bacteria are important determinants of how complex microbial communities and their interaction networks evolve in natural habitats.


Assuntos
Bactérias/genética , Evolução Molecular , Interações Microbianas/genética , Interações Microbianas/fisiologia , Microbiota/genética , Microbiota/fisiologia , Adaptação Fisiológica , Fenômenos Fisiológicos Bacterianos/genética , Proteínas de Bactérias/genética , Coevolução Biológica , Escherichia coli/genética , Escherichia coli/fisiologia , Aptidão Genética , Myxococcus xanthus/genética , Myxococcus xanthus/fisiologia , Fenótipo , Porinas/genética , Virulência
4.
Nat Commun ; 10(1): 3676, 2019 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-31417084

RESUMO

Stl is a master repressor encoded by Staphylococcus aureus pathogenicity islands (SaPIs) that maintains integration of these elements in the bacterial chromosome. After infection or induction of a resident helper phage, SaPIs are de-repressed by specific interactions of phage proteins with Stl. SaPIs have evolved a fascinating mechanism to ensure their promiscuous transfer by targeting structurally unrelated proteins performing identically conserved functions for the phage. Here we decipher the molecular mechanism of this elegant strategy by determining the structure of SaPIbov1 Stl alone and in complex with two structurally unrelated dUTPases from different S. aureus phages. Remarkably, SaPIbov1 Stl has evolved different domains implicated in DNA and partner recognition specificity. This work presents the solved structure of a SaPI repressor protein and the discovery of a modular repressor that acquires multispecificity through domain recruiting. Our results establish the mechanism that allows widespread dissemination of SaPIs in nature.


Assuntos
Proteínas de Ligação a DNA/genética , Ilhas Genômicas/genética , Fagos de Staphylococcus/genética , Staphylococcus aureus/genética , Coevolução Biológica , Cristalografia por Raios X , Modelos Moleculares
5.
J Basic Microbiol ; 59(10): 979-991, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31469183

RESUMO

This study investigates the effect of metals (cadmium, lead, mercury, and tellurium) and organic pollutants (benzene, diesel, lindane, and xylene) on a dinoflagellate-Prorocentrum sigmoides Böhm-and its associated culturable bacteria. Two bacterial cultures (Bacillus subtilis strain PD005 and B. xiamensis strain PD006) were isolated from P. sigmoides and characterized by scanning electron microscopy, 16S ribosomal RNA sequencing, biochemical analyses, and growth curve studies. This study points to a mutualistic relationship between P. sigmoides and its associated Bacillus isolates. P. sigmoides enhanced the growth of its associated Bacillus spp., through the secretion of extracellular exudates. In return, both Bacillus isolates contributed to the resistance of P. sigmoides to metals and organic pollutants. P. sigmoides and both Bacillus isolates exhibited concentration-dependent responses to metals and organic pollutants. An intriguing feature was the similar response of P. sigmoides and its associated Bacillus isolates to mercury and cadmium, indicating a co-selection of mercury and cadmium resistance. This provides support to the "dinoflagellate host-phycosphere bacteria" behaving as a single functional unit. However, the sensitivity profiles of P. sigmoides and its associated Bacillus isolates are different with respect to metals versus organic pollutants. These aspects need to be addressed in future studies to unravel the effect of metal and organic pollutants on dinoflagellates, an important component of the phytoplankton community, and to discern the influence of associated "phycosphere" bacteria on the response of dinoflagellates to pollutants.


Assuntos
Bacillus/efeitos dos fármacos , Dinoflagelados/efeitos dos fármacos , Dinoflagelados/microbiologia , Hidrocarbonetos/farmacologia , Metais/farmacologia , Poluentes Químicos da Água/farmacologia , Bacillus/genética , Bacillus/crescimento & desenvolvimento , Bacillus/ultraestrutura , Coevolução Biológica , DNA Bacteriano/genética , Dinoflagelados/metabolismo , Resistência a Medicamentos , Microscopia Eletrônica de Varredura , RNA Ribossômico 16S/genética , Simbiose
6.
Nat Microbiol ; 4(10): 1727-1736, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31285584

RESUMO

Microbiomes are vast communities of microorganisms and viruses that populate all natural ecosystems. Viruses have been considered to be the most variable component of microbiomes, as supported by virome surveys and examples of high genomic mosaicism. However, recent evidence suggests that the human gut virome is remarkably stable compared with that of other environments. Here, we investigate the origin, evolution and epidemiology of crAssphage, a widespread human gut virus. Through a global collaboration, we obtained DNA sequences of crAssphage from more than one-third of the world's countries and showed that the phylogeography of crAssphage is locally clustered within countries, cities and individuals. We also found fully colinear crAssphage-like genomes in both Old-World and New-World primates, suggesting that the association of crAssphage with primates may be millions of years old. Finally, by exploiting a large cohort of more than 1,000 individuals, we tested whether crAssphage is associated with bacterial taxonomic groups of the gut microbiome, diverse human health parameters and a wide range of dietary factors. We identified strong correlations with different clades of bacteria that are related to Bacteroidetes and weak associations with several diet categories, but no significant association with health or disease. We conclude that crAssphage is a benign cosmopolitan virus that may have coevolved with the human lineage and is an integral part of the normal human gut virome.


Assuntos
Bacteriófagos/genética , Coevolução Biológica , Microbioma Gastrointestinal , Animais , Bacteriófagos/classificação , Bacteroidetes/classificação , Bacteroidetes/genética , Bacteroidetes/virologia , DNA Viral/genética , Fezes/virologia , Feminino , Variação Genética , Humanos , Masculino , Filogenia , Filogeografia , Primatas/virologia
7.
Nat Microbiol ; 4(7): 1088-1095, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31036911

RESUMO

Mutualistic symbioses are often a source of evolutionary innovation and drivers of biological diversification1. Widely distributed in the microbial world, particularly in anoxic settings2,3, they often rely on metabolic exchanges and syntrophy2,4. Here, we report a mutualistic symbiosis observed in marine anoxic sediments between excavate protists (Symbiontida, Euglenozoa)5 and ectosymbiotic Deltaproteobacteria biomineralizing ferrimagnetic nanoparticles. Light and electron microscopy observations as well as genomic data support a multi-layered mutualism based on collective magnetotactic motility with division of labour and interspecies hydrogen-transfer-based syntrophy6. The guided motility of the consortia along the geomagnetic field is allowed by the magnetic moment of the non-motile ectosymbiotic bacteria combined with the protist motor activity, which is a unique example of eukaryotic magnetoreception7 acquired by symbiosis. The nearly complete deltaproteobacterial genome assembled from a single consortium contains a full magnetosome gene set8, but shows signs of reduction, with the probable loss of flagellar genes. Based on the metabolic gene content, the ectosymbiotic bacteria are anaerobic sulfate-reducing chemolithoautotrophs that likely reduce sulfate with hydrogen produced by hydrogenosome-like organelles6 underlying the plasma membrane of the protist. In addition to being necessary hydrogen sinks, ectosymbionts may provide organics to the protist by diffusion and predation, as shown by magnetosome-containing digestive vacuoles. Phylogenetic analyses of 16S and 18S ribosomal RNA genes from magnetotactic consortia in marine sediments across the Northern and Southern hemispheres indicate a host-ectosymbiont specificity and co-evolution. This suggests a historical acquisition of magnetoreception by a euglenozoan ancestor from Deltaproteobacteria followed by subsequent diversification. It also supports the cosmopolitan nature of this type of symbiosis in marine anoxic sediments.


Assuntos
Deltaproteobacteria/fisiologia , Euglenozoários/microbiologia , Euglenozoários/fisiologia , Campos Magnéticos , Simbiose , Anaerobiose , Coevolução Biológica , Deltaproteobacteria/classificação , Deltaproteobacteria/genética , Deltaproteobacteria/metabolismo , Euglenozoários/classificação , Euglenozoários/ultraestrutura , Eucariotos , Óxido Ferroso-Férrico/metabolismo , Genoma Bacteriano/genética , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiologia , Hidrogênio/metabolismo , Locomoção/fisiologia , Magnetossomos/genética , Magnetossomos/ultraestrutura , Oceanos e Mares , Filogenia , RNA Ribossômico/genética , Especificidade da Espécie
8.
PLoS Comput Biol ; 15(4): e1006988, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30986245

RESUMO

Exaggerated traits involved in species interactions have long captivated the imagination of evolutionary biologists and inspired the durable metaphor of the coevolutionary arms race. Despite decades of research, however, we have only a handful of examples where reciprocal coevolutionary change has been rigorously established as the cause of trait exaggeration. Support for a coevolutionary mechanism remains elusive because we lack generally applicable tools for quantifying the intensity of coevolutionary selection. Here we develop an approximate Bayesian computation (ABC) approach for estimating the intensity of coevolutionary selection using population mean phenotypes of traits mediating interspecific interactions. Our approach relaxes important assumptions of a previous maximum likelihood approach by allowing gene flow among populations, variable abiotic environments, and strong coevolutionary selection. Using simulated data, we show that our ABC method accurately infers the strength of coevolutionary selection if reliable estimates are available for key background parameters and ten or more populations are sampled. Applying our approach to the putative arms race between the plant Camellia japonica and its seed predatory weevil, Curculio camelliae, provides support for a coevolutionary hypothesis but fails to preclude the possibility of unilateral evolution. Comparing independently estimated selection gradients acting on Camellia pericarp thickness with values simulated by our model reveals a correlation between predicted and observed selection gradients of 0.941. The strong agreement between predicted and observed selection gradients validates our method.


Assuntos
Coevolução Biológica/fisiologia , Biologia Computacional/métodos , Animais , Teorema de Bayes , Coevolução Biológica/genética , Evolução Biológica , Camellia , Simulação por Computador , Ecossistema , Variação Genética/genética , Genética Populacional/métodos , Funções Verossimilhança , Fenótipo , Seleção Genética/genética , Gorgulhos
9.
PLoS One ; 14(3): e0213029, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30865672

RESUMO

The obligate mutualism and exquisite specificity of many plant-pollinator interactions lead to the expectation that flower phenotypes (e.g., corolla tube length) and corresponding pollinator traits (e.g., hawkmoth proboscis length) are congruent as a result of coevolution by natural selection. However, the effect of variation in flower morphology on the fitness of plants and their pollinators has not been quantified systematically. In this study, we employed the theoretical morphospace paradigm using a combination of 3D printing, electronic sensing, and machine vision technologies to determine the influence of two flower morphological features (corolla curvature and nectary diameter) on the fitness of both parties: the artificial flower and its hawkmoth pollinator. Contrary to the expectation that the same flower morphology maximizes the fitness of both plant and pollinator, we found that the two parties have divergent optima for corolla curvature, with non-overlapping fitness peaks in flower morphospace. The divergent fitness optima between plants and pollinators could lead to evolutionary diversification in both groups.


Assuntos
Biodiversidade , Mariposas/fisiologia , Plantas/anatomia & histologia , Polinização , Simbiose/fisiologia , Animais , Coevolução Biológica , Comportamento Alimentar , Feminino , Flores/anatomia & histologia , Masculino , Mariposas/anatomia & histologia , Fenótipo
10.
Genome Biol Evol ; 11(3): 798-813, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30753430

RESUMO

Nuclear-encoded pentatricopeptide repeat (PPR) proteins are site-specific factors for C-to-U RNA editing in plant organelles coevolving with their targets. Losing an editing target by C-to-T conversion allows for eventual loss of its editing factor, as recently confirmed for editing factors CLB19, CRR28, and RARE1 targeting ancient chloroplast editing sites in flowering plants. Here, we report on alternative evolutionary pathways for DOT4 addressing rpoC1eU488SL, a chloroplast editing site in the RNA polymerase ß' subunit mRNA. Upon loss of rpoC1eU488SL by C-to-T conversion, DOT4 got lost multiple times independently in angiosperm evolution with intermediate states of DOT4 orthologs in various stages of degeneration. Surprisingly, we now also observe degeneration and loss of DOT4 despite retention of a C in the editing position (in Carica, Coffea, Vicia, and Spirodela). We find that the cytidine remains unedited, proving that DOT4 was not replaced by another editing factor. Yet another pathway of DOT4 evolution is observed among the Poaceae. Although the rpoC1eU488SL edit has been lost through C-to-T conversion, DOT4 orthologs not only remain conserved but also have their array of PPRs extended by six additional repeats. Here, the loss of the ancient target has likely allowed DOT4 to adapt for a new function. We suggest rps3 antisense transcripts as previously demonstrated in barley (Hordeum vulgare) arising from promotor sequences newly emerging in the rpl16 intron of Poaceae as a new candidate target for the extended PPR stretch of DOT4. Altogether, DOT4 and its target show more flexible pathways for evolution than the previously explored editing factors CLB19, CRR28, and RARE1. Certain plant clades (e.g., Amaranthus, Vaccinium, Carica, the Poaceae, Fabales, and Caryophyllales) show pronounced dynamics in the evolution of editing sites and corresponding factors.


Assuntos
Proteínas de Arabidopsis/genética , Coevolução Biológica , Proteínas de Cloroplastos/genética , Evolução Molecular , Magnoliopsida/genética , Edição de RNA , Proteínas de Ligação a RNA/genética , Cloroplastos/metabolismo , Magnoliopsida/metabolismo
11.
Mol Biol Evol ; 36(5): 930-941, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30715408

RESUMO

Antagonistic chemical interactions between herbivorous insects and their host plants are often thought to coevolve in a stepwise process, with an evolutionary innovation on one side being countered by a corresponding advance on the other. Glucosinolate sulfatase (GSS) enzyme activity is essential for the Diamondback moth, Plutella xylostella, to overcome a highly diversified secondary metabolite-based host defense system in the Brassicales. GSS genes are located in an ancient cluster of arylsulfataselike genes, but the exact roles of gene copies and their evolutionary trajectories are unknown. Here, we combine a functional investigation of duplicated insect arylsulfatases with an analysis of associated nucleotide substitution patterns. We show that the Diamondback moth genome encodes three GSSs with distinct substrate spectra and distinct expression patterns in response to glucosinolates. Contrary to our expectations, early functional diversification of gene copies was not indicative of a coevolutionary arms race between host and herbivore. Instead, both copies of a duplicated arylsulfatase gene evolved concertedly in the context of an insect host shift to acquire novel detoxifying functions under positive selection, a pattern of duplicate gene retention that we call "concerted neofunctionalization."


Assuntos
Adaptação Biológica/genética , Coevolução Biológica , Herbivoria , Mariposas/genética , Sulfatases/genética , Animais , Feminino , Duplicação Gênica , Genoma de Inseto , Glucosinolatos/metabolismo , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Sulfatases/metabolismo
12.
Dev Comp Immunol ; 95: 77-88, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30742850

RESUMO

TLR7 subfamily members are important pattern recognition receptors participating in the recognition of pathogen-associated molecular patterns. In this study, we successfully identified 3 members of TLR7 subfamily from the spiny eel Mastacembelus armatus (MaTLR7, MaTLR8 and MaTLR9). The amino acid sequence identities of MaTLR7 and MaTLR8 with Monopterus albus TLR7 were 87.2% and 76.5%, respectively and the identity of MaTLR9 with Seriola lalandi TLR9 was 74.7%. The phylogenetic analysis revealed MaTLRs showed close relationship to other species in Synbranchiformes or Perciformes. Quantitative real-time PCR analysis revealed that they were expressed in all tested tissues and higher expression was found in spleen or gill. After infection with Aeromonas veronii, expression of MaTLR7, MaTLR8 and MaTLR9 were all significantly downregulated in spleen and kidney. Evolutionary analysis suggested that the ancestral lineages of teleost TLR8 and TLR9 had been subject to positive selection pressures and multiple Maximum likelihood methods recovered 3 positively selected sites in teleost TLR7, 4 in TLR8 and 8 in TLR9. Domain distribution revealed most positively selected sites were located in leucine-rich repeat domain. Our results will contribute to better understanding the antibacterial mechanism of TLRs and their co-evolution with pathogens.


Assuntos
Evolução Molecular , Proteínas de Peixes/genética , Smegmamorpha/genética , Receptor 7 Toll-Like/genética , Aeromonas veronii/imunologia , Aeromonas veronii/patogenicidade , Sequência de Aminoácidos/genética , Animais , Coevolução Biológica/genética , Coevolução Biológica/imunologia , Doenças dos Peixes/imunologia , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Negativas/imunologia , Infecções por Bactérias Gram-Negativas/microbiologia , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Imunidade Inata/genética , Filogenia , Domínios Proteicos/genética , Domínios Proteicos/imunologia , Seleção Genética , Smegmamorpha/imunologia , Smegmamorpha/microbiologia , Receptor 7 Toll-Like/imunologia
13.
Microb Ecol ; 77(4): 1036-1047, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30762095

RESUMO

Wolbachia is an intracellular endosymbiont that can produce a range of effects on host fitness, but the temporal dynamics of Wolbachia strains have rarely been experimentally evaluated. We compare interannual strain frequencies along a geographical region for understanding the forces that shape Wolbachia strain frequency in natural populations of its host, Chorthippus parallelus (Orthoptera, Acrididae). General linear models show that strain frequency changes significantly across geographical and temporal scales. Computer simulation allows to reject the compatibility of the observed patterns with either genetic drift or sampling errors. We use consecutive years to estimate total Wolbachia strain fitness. Our estimation of Wolbachia fitness is significant in most cases, within locality and between consecutive years, following a negatively frequency-dependent trend. Wolbachia spp. B and F strains show a temporal pattern of variation that is compatible with a negative frequency-dependent natural selection mechanism. Our results suggest that such a mechanism should be at least considered in future experimental and theoretical research strategies that attempt to understand Wolbachia biodiversity.


Assuntos
Gafanhotos/microbiologia , Polimorfismo Genético , Simbiose , Wolbachia/fisiologia , Animais , Coevolução Biológica , Simulação por Computador , Geografia , Modelos Lineares , Estações do Ano , Wolbachia/genética
14.
Viruses ; 11(2)2019 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-30699954

RESUMO

The coevolution between phage and host bacterium is an important force that drives the evolution of the microbial community, yet the coevolution mechanisms have still not been well analyzed. Here, by analyzing the interaction between a Bacillus phage vB_BthS_BMBphi and its host bacterium, the coevolution mechanisms of the first-generation phage-resistant bacterial mutants and regained-infectivity phage mutants were studied. The phage-resistant bacterial mutants showed several conserved mutations as a potential reason for acquiring phage resistance, including the mutation in flagellum synthesis protein FlhA and cell wall polysaccharide synthesis protein DltC. All the phage-resistant bacterial mutants showed a deleted first transmembrane domain of the flagellum synthesis protein FlhA. Meanwhile, the regain-infectivity phage mutants all contained mutations in three baseplate-associated phage tail proteins by one nucleotide, respectively. A polymorphism analysis of the three mutant nucleotides in the wild-type phage revealed that the mutations existed before the interaction of the phage and the bacterium, while the wild-type phage could not infect the phage-resistant bacterial mutants, which might be because the synchronized mutations of the three nucleotides were essential for regaining infectivity. This study for the first time revealed that the synergism mutation of three phage baseplate-associated proteins were essential for the phages' regained infectivity. Although the phage mutants regained infectivity, their storage stability was decreased and the infectivity against the phage-resistant bacterial mutants was reduced, suggesting the phage realized the continuation of the species by way of "dying to survive".


Assuntos
Fagos Bacilares/genética , Coevolução Biológica , Evolução Molecular , Interações entre Hospedeiro e Microrganismos/genética , Mutação , Bacillus/genética , Bacillus/virologia , Proteínas de Bactérias/genética , Proteínas de Transporte/genética , Proteínas de Membrana/genética
15.
Cell Host Microbe ; 25(2): 210-218, 2019 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-30763535

RESUMO

The intestinal microbiota is intimately linked to human health. Decoding the mechanisms underlying its stability in healthy subjects should uncover causes of microbiota-associated diseases and pave the way for treatment. Bacteria and bacteriophages (phages) are the most abundant biological entities in the gastrointestinal tract, where their coexistence is dynamic and affixed. Phages drive and maintain bacterial diversity by perpetuating the coevolutionary interactions with their microbial prey. This review brings together recent in silico, in vitro, and in vivo work dissecting the complexity of phage-bacteria interactions in the intestinal microbiota, including coevolution perspectives. We define the types of dynamics encountered in the gastrointestinal tract and the parameters that affect their outcome. The impact of intestinal physiology on phage-bacterial coevolution is analyzed in the light of its potential contribution to the relationship between the microbiota and human health.


Assuntos
Bactérias/virologia , Bacteriófagos/fisiologia , Trato Gastrointestinal/microbiologia , Interações Microbianas , Animais , Coevolução Biológica , Microbioma Gastrointestinal/fisiologia , Humanos , Camundongos , Organismos Livres de Patógenos Específicos
16.
Am Nat ; 193(3): 321-330, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30794449

RESUMO

Species do not live, interact, or evolve in isolation but are instead members of complex ecological communities. In ecological terms, complex multispecies interactions can be understood by considering indirect effects that are mediated by changes in traits and abundances of intermediate species. Interestingly, traits and abundances are also central to our understanding of phenotypic selection, suggesting that indirect effects may be extended to understand evolution in complex communities. Here we explore indirect ecological effects and their evolutionary corollary in a well-understood food web comprising a plant, its herbivores, and enemies that select for opposite defensive phenotypes in one of the herbivores. We show that ecological indirect interactions are mediated by changes to both the traits and the abundances of intermediate species and that these changes ultimately reduce enemy attack and weaken selection. We discuss the generality of the link between indirect effects and selection. We go on to argue that local adaptation and eco-evolutionary feedback may be less likely in complex multispecies food webs than in simpler food chains (e.g., coevolution). Overall, considering selection in complex interaction networks can facilitate the rapprochement of community ecology and evolution.


Assuntos
Coevolução Biológica , Cadeia Alimentar , Herbivoria , Tumores de Planta , Seleção Genética , Animais , Besouros , Larva , Densidade Demográfica , Distribuição Aleatória , Solidago , Tephritidae
17.
Am Nat ; 193(2): E29-E40, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30720358

RESUMO

The relationships between mating decisions and parental investment are central to evolution, but to date few theoretical treatments of their coevolution have been developed. Here we adopt a demographically explicit, adaptive dynamics approach to analyze the coevolution of female mating decisions and parental investment of both sexes in a self-consistent way. Our models predict that where females cannot interfere with one another's mating decisions and where they do not differ in their survival and fecundity prospects, monogamy should be rare, favored only under harsh environmental conditions, in sparse populations. However, allowing for interference or asymmetries among females leads to selection for monogamy over a much broader range of environments and demographies. Interference by paired, resident females may prevent unmated rivals from joining existing monogamous pairs, thus barring the formation of polygynous groups. Asymmetries between established, primary females and subsequently joining secondary females may increase the relative costs of early polygynous reproduction, compared to delayed monogamy for the latter. The models thus highlight different routes by which monogamy may evolve. We further track how parental investment by the sexes coevolves with female mating decisions, highlighting how sexual conflict over parental investment is both cause and effect of mating behavior.


Assuntos
Coevolução Biológica , Comportamento Materno/fisiologia , Modelos Genéticos , Ligação do Par , Comportamento Paterno/fisiologia , Animais , Feminino , Teoria do Jogo , Masculino , Preferência de Acasalamento Animal , Razão de Masculinidade
18.
Am Nat ; 193(1): E1-E14, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30624111

RESUMO

In many taxa, there is a conflict between the sexes over mating rate. The outcome of sexually antagonistic coevolution depends on the costs of mating and natural selection against sexually antagonistic traits. A sexually transmitted infection (STI) changes the relative strength of these costs. We study the three-way evolutionary interaction among male persistence, female resistance, and STI virulence for two types of STIs: a viability-reducing STI and a reproduction-reducing STI. A viability-reducing STI escalates conflict between the sexes. This leads to increased STI virulence (i.e., full coevolution) if the costs of sexually antagonistic traits occur through viability but not through reproduction. In contrast, a reproduction-reducing STI de-escalates the sexual conflict, but STI virulence does not coevolve in response. We also investigated the establishment probability of STIs under different combinations of evolvability. Successful invasion by a viability-reducing STI becomes less likely if hosts (but not parasites) are evolvable, especially if only the female trait can evolve. A reproduction-reducing STI can almost always invade because it does not kill its host. We discuss how the evolution of host and parasite traits in a system with sexual conflict differs from a system with female mate choice.


Assuntos
Coevolução Biológica , Modelos Biológicos , Doenças Sexualmente Transmissíveis , Animais , Feminino , Masculino , Reprodução , Comportamento Sexual Animal , Virulência
19.
Mol Biol Evol ; 36(2): 341-349, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30445640

RESUMO

The diploid D-genome lineage of the Triticum/Aegilops complex has an evolutionary history involving genomic contributions from ancient A- and B/S-genome species. We explored here the possible cytonuclear evolutionary responses to this history of hybridization. Phylogenetic analysis of chloroplast DNAs indicates that the D-genome lineage has a maternal origin of the A-genome or some other closely allied lineage. Analyses of the nuclear genome in the D-genome species Aegilops tauschii indicate that accompanying and/or following this ancient hybridization, there has been biased maintenance of maternal A-genome ancestry in nuclear genes encoding cytonuclear enzyme complexes (CECs). Our study provides insights into mechanisms of cytonuclear coevolution accompanying the evolution and eventual stabilization of homoploid hybrid species. We suggest that this coevolutionary process includes likely rapid fixation of A-genome CEC orthologs as well as biased retention of A-genome nucleotides in CEC homologs following population level recombination during the initial generations.


Assuntos
Aegilops/genética , Coevolução Biológica , Especiação Genética , Genoma de Planta , Hibridização Genética , Aegilops/citologia , Epistasia Genética , Genes de Cloroplastos , Filogenia
20.
Gut Microbes ; 10(1): 92-99, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-29913091

RESUMO

Viruses that infect bacteria, or bacteriophages, are among the most abundant entities in the gut microbiome. However, their role and the mechanisms by which they infect bacteria in the intestinal tract remain poorly understood. We recently reported that intestinal bacteria are an evolutionary force, driving the expansion of the bacteriophage host range by boosting the genetic variability of these viruses. Here, we expand these observations by studying antagonistic bacteriophage-bacteria coevolution dynamics and revealing that bacterial genetic variability is also increased under the pressure of bacteriophage predation. We propose a model showing how the expansion of bacteriophage-bacteria infection networks is relative to the opportunities for coevolution encountered in the intestinal tract. Our data suggest that predator-prey dynamics are perpetuated and differentiated in parallel, to generate and maintain intestinal microbial diversity and equilibrium.


Assuntos
Bactérias/virologia , Bacteriófagos/fisiologia , Coevolução Biológica , Microbioma Gastrointestinal/fisiologia , Adaptação Fisiológica , Animais , Antibiose/genética , Bactérias/genética , Bacteriófagos/genética , Biodiversidade , Microbioma Gastrointestinal/genética , Variação Genética , Humanos , Intestinos/microbiologia , Intestinos/virologia , Modelos Biológicos
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