Base de dados : MEDLINE
Pesquisa : B04.123.470.500 [Categoria DeCS]
Referências encontradas : 17 [refinar]
Mostrando: 1 .. 10   no formato [Detalhado]

página 1 de 2 ir para página        

  1 / 17 MEDLINE  
              next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:27383372
[Au] Autor:Diemer GS; Stedman KM
[Ad] Endereço:Vaccine and Gene Therapy Institute, Oregon Health and Science University, 505 NW 185th Ave, Beaverton, OR, 97006, USA. diemer.g.phd@gmail.com.
[Ti] Título:Modeling Microvirus Capsid Protein Evolution Utilizing Metagenomic Sequence Data.
[So] Source:J Mol Evol;83(1-2):38-49, 2016 Aug.
[Is] ISSN:1432-1432
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:The Microviridae are increasingly becoming recognized as one of the most globally ubiquitous and highly diverse virus families, and as such, provide an advantageous model for studying virus evolution and adaptation. Here, we utilize microvirus sequences from diverse physiochemical environments, including novel sequences from a high-temperature acidic lake, to chart the outcome of natural selection in the main structural protein of the virus. Each icosahedral microvirus virion is composed of sixty identical capsid proteins that interact along twofold, threefold and fivefold symmetry axis interfaces to encapsidate a small, circular, single-stranded DNA genome. Viable assembly of the virus is guided by scaffolding proteins, which coordinate inter-subunit contacts between the capsid proteins. Structure-based analysis indicates that amino acid sequence conservation is predominantly localized to the twofold axis interface. While preservation of this quaternary interface appears to be essential, tertiary and secondary structural features of the capsid protein are permissive to considerable sequence variation.
[Mh] Termos MeSH primário: Proteínas do Capsídeo/genética
Microvirus/genética
Análise de Sequência de DNA/métodos
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Capsídeo/fisiologia
DNA de Cadeia Simples
Evolução Molecular
Variação Genética
Microviridae/genética
Modelos Moleculares
Vírion/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Capsid Proteins); 0 (DNA, Single-Stranded)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:170922
[Lr] Data última revisão:
170922
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160708
[St] Status:MEDLINE
[do] DOI:10.1007/s00239-016-9751-y


  2 / 17 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:26025979
[Au] Autor:Doore SM; Fane BA
[Ad] Endereço:School of Plant Sciences and the BIO5 Institute, University of Arizona.
[Ti] Título:The Kinetic and Thermodynamic Aftermath of Horizontal Gene Transfer Governs Evolutionary Recovery.
[So] Source:Mol Biol Evol;32(10):2571-84, 2015 Oct.
[Is] ISSN:1537-1719
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Shared host cells can serve as melting pots for viral genomes, giving many phylogenies a web-like appearance due to horizontal gene transfer. However, not all virus families exhibit web-like phylogenies. Microviruses form three distinct clades, represented by φX174, G4, and α3. Here, we investigate protein-based barriers to horizontal gene transfer between clades. We transferred gene G, which encodes a structural protein, between φX174 and G4, and monitored the evolutionary recovery of the resulting chimeras. In both cases, particle assembly was the major barrier after gene transfer. The G4φXG chimera displayed a temperature-sensitive assembly defect that could easily be corrected through single mutations that promote productive assembly. Gene transfer in the other direction was more problematic. The initial φXG4G chimera required an exogenous supply of both the φX174 major spike G and DNA pilot H proteins. Elevated DNA pilot protein levels may be required to compensate for off-pathway reactions that may have become thermodynamically and/or kinetically favored when the foreign spike protein was present. After three targeted genetic selections, the foreign spike protein was productively integrated into the φX174 background. The first adaption involved a global decrease in gene expression. This was followed by modifications affecting key protein-protein interactions that govern assembly. Finally, gene expression was re-elevated. Although the first selection suppresses nonproductive reactions, subsequent selections promote productive assembly and ultimately viability. However, viable chimeric strains exhibited reduced fitness compared with wild-type. This chimera's path to recovery may partially explain how unusual recombinant viruses could persist long enough to naturally emerge.
[Mh] Termos MeSH primário: Evolução Biológica
Transferência Genética Horizontal
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Bacteriófago phi X 174/genética
Bacteriófago phi X 174/fisiologia
Códon de Terminação/genética
Regulação Viral da Expressão Gênica
Genes Virais
Cinética
Microvirus/genética
Microvirus/fisiologia
Dados de Sequência Molecular
Mutação/genética
Fenótipo
Filogenia
Alinhamento de Sequência
Temperatura Ambiente
Termodinâmica
Proteínas Virais/química
Proteínas Virais/metabolismo
Vírion/metabolismo
Montagem de Vírus
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Codon, Terminator); 0 (Viral Proteins)
[Em] Mês de entrada:1606
[Cu] Atualização por classe:150922
[Lr] Data última revisão:
150922
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150531
[St] Status:MEDLINE
[do] DOI:10.1093/molbev/msv130


  3 / 17 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PubMed Central Texto completo
Texto completo
[PMID]:25275498
[Au] Autor:McGee LW; Aitchison EW; Caudle SB; Morrison AJ; Zheng L; Yang W; Rokyta DR
[Ad] Endereço:Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America.
[Ti] Título:Payoffs, not tradeoffs, in the adaptation of a virus to ostensibly conflicting selective pressures.
[So] Source:PLoS Genet;10(10):e1004611, 2014 Oct.
[Is] ISSN:1553-7404
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The genetic architecture of many phenotypic traits is such that genes often contribute to multiple traits, and mutations in these genes can therefore affect multiple phenotypes. These pleiotropic interactions often manifest as tradeoffs between traits where improvement in one property entails a cost in another. The life cycles of many pathogens include periods of growth within a host punctuated with transmission events, such as passage through a digestive tract or a passive stage of exposure in the environment. Populations exposed to such fluctuating selective pressures are expected to acquire mutations showing tradeoffs between reproduction within and survival outside of a host. We selected for individual mutations under fluctuating selective pressures for a ssDNA microvirid bacteriophage by alternating selection for increased growth rate with selection on biophysical properties of the phage capsid in high-temperature or low-pH conditions. Surprisingly, none of the seven unique mutations identified showed a pleiotropic cost; they all improved both growth rate and pH or temperature stability, suggesting that single mutations even in a simple genetic system can simultaneously improve two distinct traits. Selection on growth rate alone revealed tradeoffs, but some mutations still benefited both traits. Tradeoffs were therefore prevalent when selection acted on a single trait, but payoffs resulted when multiple traits were selected for simultaneously. We employed a molecular-dynamics simulation method to determine the mechanisms underlying beneficial effects for three heat-shock mutations. All three mutations significantly enhanced the affinities of protein-protein interfacial bindings, thereby improving capsid stability. The ancestral residues at the mutation sites did not contribute to protein-protein interfacial binding, indicating that these sites acquired a new function. Computational models, such as those used here, may be used in future work not only as predictive tools for mutational effects on protein stability but, ultimately, for evolution.
[Mh] Termos MeSH primário: Adaptação Fisiológica/genética
Microvirus/fisiologia
Seleção Genética
[Mh] Termos MeSH secundário: Capsídeo/metabolismo
Aptidão Genética
Resposta ao Choque Térmico/genética
Concentração de Íons de Hidrogênio
Microvirus/química
Microvirus/genética
Microvirus/crescimento & desenvolvimento
Mutação
Temperatura Ambiente
Proteínas Virais/genética
Proteínas Virais/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (Viral Proteins)
[Em] Mês de entrada:1604
[Cu] Atualização por classe:171115
[Lr] Data última revisão:
171115
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:141003
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pgen.1004611


  4 / 17 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:24600050
[Au] Autor:Doore SM; Baird CD; Roznowski AP; Fane BA; 2012 University of Arizona Virology Undergraduate Lab
[Ad] Endereço:School of Plant Sciences and the BIO5 Institute, University of Arizona.
[Ti] Título:The evolution of genes within genes and the control of DNA replication in microviruses.
[So] Source:Mol Biol Evol;31(6):1421-31, 2014 Jun.
[Is] ISSN:1537-1719
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Single-stranded DNA(ssDNA) viral life cycles must balance double-stranded DNA (dsDNA) and ssDNA biosynthesis. Previously published in vitro results suggest that microvirus C and host cell SSB proteins play antagonistic roles to achieve this balance. To investigate this in vivo, microvirus DNA replication was characterized in cells expressing cloned C or ssb genes, which would presumably alter the C:SSB protein ratios. Representatives of each microvirus clade (φX174, G4, and α3) were used in these studies. α3 DNA replication was significantly more complex. Results suggested that the recognized α3 C gene (C(S): small) is one of two C genes. A larger 5' extended gene could be translated from an upstream GTG start codon (C(B): big). Wild-type α3 acquired resistance to elevated SSB levels by mutations that exclusively frameshifted the C(B) reading frame, whereas mutations in the origin of replication conferred resistance to elevated C protein levels. Expression of either the cloned C(B) or C(S) gene complemented am(C) mutants, demonstrating functional redundancy. When the C(S) start codon was eliminated, strains were only viable if an additional amber mutation was placed in gene C and propagated in an informational suppressing host. Thus, C(B) protein likely reaches toxic levels in the absence of C(S) translation. This phenomenon may have driven the evolution of the C(S) gene within the larger C(B) gene and could constitute a unique mechanism of regulation. Furthermore, cross-complementation data suggested that interactions between the α3 C and other viral proteins have evolved enough specificity to biochemically isolate its DNA replication from G4 and φX174.
[Mh] Termos MeSH primário: Proteínas de Ligação a DNA/metabolismo
Proteínas de Escherichia coli/metabolismo
Escherichia coli/metabolismo
Microvirus/crescimento & desenvolvimento
Microvirus/genética
Proteínas Virais/metabolismo
[Mh] Termos MeSH secundário: Replicação do DNA
DNA de Cadeia Simples/metabolismo
DNA Viral/metabolismo
Escherichia coli/virologia
Evolução Molecular
Genes Virais
Microvirus/classificação
Mutação
Filogenia
Proteínas Virais/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (DNA, Single-Stranded); 0 (DNA, Viral); 0 (DNA-Binding Proteins); 0 (Escherichia coli Proteins); 0 (SSB protein, E coli); 0 (Viral Proteins)
[Em] Mês de entrada:1501
[Cu] Atualização por classe:140526
[Lr] Data última revisão:
140526
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140307
[St] Status:MEDLINE
[do] DOI:10.1093/molbev/msu089


  5 / 17 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PubMed Central Texto completo
Texto completo
[PMID]:22110602
[Au] Autor:Yang R; Han Y; Ye Y; Liu Y; Jiang Z; Gui Y; Cai Z
[Ad] Endereço:Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China.
[Ti] Título:Chemical synthesis of bacteriophage G4.
[So] Source:PLoS One;6(11):e27062, 2011.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Due to recent leaps forward in DNA synthesis and sequencing technology, DNA manipulation has been extended to the level of whole-genome synthesis. Bacteriophages occupy a special niche in the micro-organic ecosystem and have potential as a tool for therapeutic agent. The purpose of this study was to carry out chemical synthesis of the bacteriophage G4 and the study of its infectivity. METHODOLOGY/PRINCIPAL FINDINGS: Full-sized genomes of bacteriophage G4 molecules were completed from short overlapping synthetic oligonucleotides by direct assembly polymerase chain reaction and ligase chain reaction followed by fusion polymerase chain reaction with flanking primers. Three novel restriction endonuclease sites were introduced to distinguish the synthetic G4 from the wild type. G4 particles were recovered after electroporation into Escherichia coli and were efficient enough to infect another strain. The phage was validated by electron microscope. Specific polymerase chain reaction assay and restriction analyses of the plaques verified the accuracy of the chemical synthetic genomes. CONCLUSIONS: Our results showed that the bacteriophage G4 obtained is synthetic rather than a wild type. Our study demonstrated that a phage can be synthesized and manipulated genetically according to the sequences, and can be efficient enough to infect the Escherichia coli, showing the potential use of synthetic biology in medical application.
[Mh] Termos MeSH primário: Microvirus/genética
Biologia Sintética/métodos
[Mh] Termos MeSH secundário: Enzimas de Restrição do DNA/metabolismo
Escherichia coli/virologia
Genoma Viral/genética
Microscopia Eletrônica
Microvirus/fisiologia
Microvirus/ultraestrutura
Reação em Cadeia da Polimerase
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
EC 3.1.21.- (DNA Restriction Enzymes)
[Em] Mês de entrada:1203
[Cu] Atualização por classe:170220
[Lr] Data última revisão:
170220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:111124
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0027062


  6 / 17 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PubMed Central Texto completo
Texto completo
[PMID]:21714899
[Au] Autor:Zsak L; Day JM; Oakley BB; Seal BS
[Ad] Endereço:Southeast Poultry Research Laboratory, Agricultural Research Service, United States Department of Agriculture, 934 College Station Road, Athens, GA 30605, USA. laszlo.zsak@ars.usda.gov
[Ti] Título:The complete genome sequence and genetic analysis of ΦCA82 a novel uncultured microphage from the turkey gastrointestinal system.
[So] Source:Virol J;8:331, 2011 Jun 29.
[Is] ISSN:1743-422X
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The genomic DNA sequence of a novel enteric uncultured microphage, ΦCA82 from a turkey gastrointestinal system was determined utilizing metagenomics techniques. The entire circular, single-stranded nucleotide sequence of the genome was 5,514 nucleotides. The ΦCA82 genome is quite different from other microviruses as indicated by comparisons of nucleotide similarity, predicted protein similarity, and functional classifications. Only three genes showed significant similarity to microviral proteins as determined by local alignments using BLAST analysis. ORF1 encoded a predicted phage F capsid protein that was phylogenetically most similar to the Microviridae ΦMH2K member's major coat protein. The ΦCA82 genome also encoded a predicted minor capsid protein (ORF2) and putative replication initiation protein (ORF3) most similar to the microviral bacteriophage SpV4. The distant evolutionary relationship of ΦCA82 suggests that the divergence of this novel turkey microvirus from other microviruses may reflect unique evolutionary pressures encountered within the turkey gastrointestinal system.
[Mh] Termos MeSH primário: DNA Viral/genética
Trato Gastrointestinal/virologia
Genoma Viral
Microvirus/genética
Microvirus/isolamento & purificação
Análise de Sequência de DNA
[Mh] Termos MeSH secundário: Animais
DNA Circular/química
DNA Circular/genética
DNA de Cadeia Simples/química
DNA de Cadeia Simples/genética
DNA Viral/química
Ordem dos Genes
Dados de Sequência Molecular
Fases de Leitura Aberta
Filogenia
Homologia de Sequência
Perus
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (DNA, Circular); 0 (DNA, Single-Stranded); 0 (DNA, Viral)
[Em] Mês de entrada:1110
[Cu] Atualização por classe:150204
[Lr] Data última revisão:
150204
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:110701
[St] Status:MEDLINE
[do] DOI:10.1186/1743-422X-8-331


  7 / 17 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:19232002
[Au] Autor:Knies JL; Kingsolver JG; Burch CL
[Ad] Endereço:Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA. jennifer_knies@brown.edu
[Ti] Título:Hotter is better and broader: thermal sensitivity of fitness in a population of bacteriophages.
[So] Source:Am Nat;173(4):419-30, 2009 Apr.
[Is] ISSN:1537-5323
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Hotter is better is a hypothesis of thermal adaptation that posits that the rate-depressing effects of low temperature on biochemical reactions cannot be overcome by physiological plasticity or genetic adaptation. If so, then genotypes or populations adapted to warmer temperatures will have higher maximum growth rates than those adapted to low temperatures. Here we test hotter is better by measuring thermal reaction norms for intrinsic rate of population growth among an intraspecific collection of bacteriophages recently isolated from nature. Consistent with hotter is better, we find that phage genotypes with higher optimal temperatures have higher maximum growth rates. Unexpectedly, we also found that hotter is broader, meaning that the phages with the highest optimal temperatures also have the greatest temperature ranges. We found that the temperature sensitivity of fitness for phages is similar to that for insects.
[Mh] Termos MeSH primário: Adaptação Biológica/fisiologia
Temperatura Alta
Microvirus/crescimento & desenvolvimento
Modelos Biológicos
[Mh] Termos MeSH secundário: Teorema de Bayes
Genótipo
Microvirus/genética
Modelos Genéticos
Filogenia
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Em] Mês de entrada:0906
[Cu] Atualização por classe:090309
[Lr] Data última revisão:
090309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:090224
[St] Status:MEDLINE
[do] DOI:10.1086/597224


  8 / 17 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PubMed Central Texto completo
[PMID]:17553892
[Au] Autor:Uchiyama A; Chen M; Fane BA
[Ad] Endereço:Department of Veterinary Sciences and Microbiology, University of Arizona, Tucson, AZ 85721-0090, USA.
[Ti] Título:Characterization and function of putative substrate specificity domain in microvirus external scaffolding proteins.
[So] Source:J Virol;81(16):8587-92, 2007 Aug.
[Is] ISSN:0022-538X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Microviruses (canonical members are bacteriophages phiX174, G4, and alpha3) are T=1 icosahedral virions with an assembly pathway mediated by two scaffolding proteins. The external scaffolding protein D plays a major role during morphogenesis, particularly in icosahedral shell formation. The results of previous studies, conducted with a cloned chimeric external scaffolding gene, suggest that the first alpha-helix acts as a substrate specificity domain, perhaps mediating the initial coat-external scaffolding protein interaction. However, the expression of a cloned gene could lead to protein concentrations higher than those found in typical infections. Moreover, its induction before infection could alter the timing of the protein's accumulation. Both of these factors could drive or facilitate reactions that may not occur under physiological conditions or before programmed cell lysis. In order to elucidate a more detailed mechanistic model, a chimeric external scaffolding gene was placed directly in the phiX174 genome under wild-type transcriptional and translational control, and the chimeric virus, which was not viable on the level of plaque formation, was characterized. The results of the genetic and biochemical analyses indicate that alpha-helix 1 most likely mediates the nucleation reaction for the formation of the first assembly intermediate containing the external scaffolding protein. Mutants that can more efficiently use the chimeric scaffolding protein were isolated. These second-site mutations appear to act on a kinetic level, shortening the lag phase before virion production, perhaps lowering the critical concentration of the chimeric protein required for a nucleation reaction.
[Mh] Termos MeSH primário: Bacteriófago phi X 174/crescimento & desenvolvimento
Microvirus/crescimento & desenvolvimento
Proteínas Estruturais Virais/metabolismo
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Bacteriófago phi X 174/química
Bacteriófago phi X 174/genética
Genes Virais
Genoma Viral
Cinética
Microvirus/química
Microvirus/genética
Dados de Sequência Molecular
Mutação
Estrutura Secundária de Proteína
Estrutura Terciária de Proteína
Proteínas Recombinantes de Fusão/química
Proteínas Recombinantes de Fusão/genética
Proteínas Recombinantes de Fusão/metabolismo
Especificidade por Substrato
Proteínas Estruturais Virais/química
Proteínas Estruturais Virais/genética
Vírion/química
Vírion/genética
Vírion/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Recombinant Fusion Proteins); 0 (Viral Structural Proteins)
[Em] Mês de entrada:0709
[Cu] Atualização por classe:140904
[Lr] Data última revisão:
140904
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:070608
[St] Status:MEDLINE


  9 / 17 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PubMed Central Texto completo
[PMID]:16732695
[Au] Autor:Knies JL; Izem R; Supler KL; Kingsolver JG; Burch CL
[Ad] Endereço:Department of Biology, University of North Carolina, Chapel Hill, North Carolina, USA.
[Ti] Título:The genetic basis of thermal reaction norm evolution in lab and natural phage populations.
[So] Source:PLoS Biol;4(7):e201, 2006 Jul.
[Is] ISSN:1545-7885
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Two major goals of laboratory evolution experiments are to integrate from genotype to phenotype to fitness, and to understand the genetic basis of adaptation in natural populations. Here we demonstrate that both goals are possible by re-examining the outcome of a previous laboratory evolution experiment in which the bacteriophage G4 was adapted to high temperatures. We quantified the evolutionary changes in the thermal reaction norms--the curves that describe the effect of temperature on the growth rate of the phages--and decomposed the changes into modes of biological interest. Our analysis indicated that changes in optimal temperature accounted for almost half of the evolutionary changes in thermal reaction norm shape, and made the largest contribution toward adaptation at high temperatures. Genome sequencing allowed us to associate reaction norm shape changes with particular nucleotide mutations, and several of the identified mutations were found to be polymorphic in natural populations. Growth rate measures of natural phage that differed at a site that contributed substantially to adaptation in the lab indicated that this mutation also underlies thermal reaction norm shape variation in nature. In combination, our results suggest that laboratory evolution experiments may successfully predict the genetic bases of evolutionary responses to temperature in nature. The implications of this work for viral evolution arise from the fact that shifts in the thermal optimum are characterized by tradeoffs in performance between high and low temperatures. Optimum shifts, if characteristic of viral adaptation to novel temperatures, would ensure the success of vaccine development strategies that adapt viruses to low temperatures in an attempt to reduce virulence at higher (body) temperatures.
[Mh] Termos MeSH primário: Evolução Biológica
Microvirus/genética
[Mh] Termos MeSH secundário: Sequência de Bases
Escherichia coli/virologia
Variação Genética
Genoma Viral
Microvirus/classificação
Microvirus/crescimento & desenvolvimento
Filogenia
Temperatura Ambiente
Cultura de Vírus/métodos
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Em] Mês de entrada:0612
[Cu] Atualização por classe:161206
[Lr] Data última revisão:
161206
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:060531
[St] Status:MEDLINE


  10 / 17 MEDLINE  
              first record previous record
seleciona
para imprimir
Fotocópia
PubMed Central Texto completo
[PMID]:11779783
[Au] Autor:Holder KK; Bull JJ
[Ad] Endereço:Section of Integrative Biology, Institute of Cellular and Molecular Biology, University of Texas, Austin, Texas 78712-1023, USA.
[Ti] Título:Profiles of adaptation in two similar viruses.
[So] Source:Genetics;159(4):1393-404, 2001 Dec.
[Is] ISSN:0016-6731
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The related bacteriophages phiX174 and G4 were adapted to the inhibitory temperature of 44 degrees and monitored for nucleotide changes throughout the genome. Phage were evolved by serial transfer at low multiplicity of infection on rapidly dividing bacteria to select genotypes with the fastest rates of reproduction. Both phage showed overall greater fitness effects per substitution during the early stages of adaptation. The fitness of phiX174 improved from -0.7 to 5.6 doublings of phage concentration per generation. Five missense mutations were observed. The earliest two mutations accounted for 85% of the ultimate fitness gain. In contrast, G4 required adaptation to the intermediate temperature of 41.5 degrees before it could be maintained at 44 degrees. Its fitness at 44 degrees increased from -2.7 to 3.2, nearly the same net gain as in phiX174, but with three times the opportunity for adaptation. Seventeen mutations were observed in G4: 14 missense, 2 silent, and 1 intergenic. The first 3 missense substitutions accounted for over half the ultimate fitness increase. Although the expected pattern of periodic selective sweeps was the most common one for both phage, some mutations were lost after becoming frequent, and long-term polymorphism was observed. This study provides the greatest detail yet in combining fitness profiles with the underlying pattern of genetic changes, and the results support recent theories on the range of fitness effects of substitutions fixed during adaptation.
[Mh] Termos MeSH primário: DNA Viral
Evolução Molecular
Vírus/genética
[Mh] Termos MeSH secundário: Bacteriófago phi X 174/genética
Genoma Viral
Genótipo
Microvirus/genética
Mutação
Temperatura Ambiente
Fatores de Tempo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, P.H.S.
[Nm] Nome de substância:
0 (DNA, Viral)
[Em] Mês de entrada:0203
[Cu] Atualização por classe:161019
[Lr] Data última revisão:
161019
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:020110
[St] Status:MEDLINE



página 1 de 2 ir para página        
   


Refinar a pesquisa
  Base de dados : MEDLINE Formulário avançado   

    Pesquisar no campo  
1  
2
3
 
           



Search engine: iAH v2.6 powered by WWWISIS

BIREME/OPAS/OMS - Centro Latino-Americano e do Caribe de Informação em Ciências da Saúde