scholarly journals Evidence for shared ancestry between Actinobacteria and Firmicutes bacteriophages

2019 ◽  
Author(s):  
Matthew Koert ◽  
Júlia López-Pérez ◽  
Courtney Mattson ◽  
Steven Caruso ◽  
Ivan Erill
Keyword(s):  
Common Ancestor ◽  
Selective Pressure ◽  
Genome Structure ◽  
Gc Content ◽  
Bacterial Strains ◽  
Large Numbers ◽  
Shared Ancestry ◽  
Small Set ◽  
Public Repositories ◽  
Genomic Gc Content

AbstractBacteriophages typically infect a small set of related bacterial strains. The transfer of bacteriophages between more distant clades of bacteria has often been postulated, but remains mostly unaddressed. In this work we leverage the sequencing of a novel cluster of phages infecting Streptomyces bacteria and the availability of large numbers of complete phage genomes in public repositories to address this question. Using phylogenetic and comparative genomics methods, we show that several clusters of Actinobacteria-infecting phages are more closely related between them, and with a small group of Firmicutes phages, than with any other actinobacteriophage lineage. These data indicate that this heterogeneous group of phages shares a common ancestor with well-defined genome structure. Analysis of genomic %GC content and codon usage bias shows that these actinobacteriophages are poorly adapted to their Actinobacteria hosts, suggesting that this phage lineage could have originated in an ancestor of the Firmicutes, adapted to the high %GC content members of this phylum, and later migrated to the Actinobacteria, or that selective pressure for enhanced translational throughput is significantly lower for phages infecting Actinobacteria hosts.

scholarly journals Analysis of Six Chloroplast Genomes Provides Insight into the Evolution of Chrysosplenium (Saxifragaceae)

2020 ◽  
Author(s):  
Zhihua Wu ◽  
Rui Liao ◽  
Tiange Yang ◽  
Xiang Dong ◽  
Deqing Lan ◽  
...  
Keyword(s):  
Positive Selection ◽  
Selective Pressure ◽  
Phylogenetic Analyses ◽  
Genome Structure ◽  
Gc Content ◽  
Light Conditions ◽  
Low Light ◽  
Plant Adaptation ◽  
Chloroplast Genomes ◽  
Pressure Estimation

Abstract Background: Chrysosplenium L. (Saxifragaceae) is a genus of plants widely distributed in Northern Hemisphere and usually found in moist, shaded valleys and mountain slopes. This genus is ideal for studying plant adaptation to low light conditions. Although some progress has been made in the systematics and biogeography of Chrysosplenium, its chloroplast genome evolution remains to be investigated. Results: To fill this gap, we sequenced the chloroplast genomes of six Chrysosplenium species and analyzed their genome structure, GC content, and nucleotide diversity. Moreover, we performed a phylogenetic analysis and calculated non-synonymous (Ka) /synonymous (Ks) substitution ratios using the combined protein-coding genes of 29 species within Saxifragales and two additional species as outgroups, as well as a pair-wise estimation for each gene within Chrysosplenium. Compared with the outgroups in Saxifragaceae, the six Chrysosplenium chloroplast genomes had lower GC contents; they also had conserved boundary regions and gene contents, as only the rpl32 gene was lost in four of the Chrysosplenium chloroplast genomes. Phylogenetic analyses suggested that the Chrysosplenium separated to two major clades (the opposite group and the alternate group). The selection pressure estimation (Ka/Ks ratios) of genes in the Chrysosplenium species showed that matK and ycf2 were subjected to positive selection.Conclusion: This study provides genetic resources for exploring the phylogeny of Chrysosplenium and sheds light on plant adaptation to low light conditions. The lower average GC content and the lacking gene of rpl32 indicated selective pressure in their unique habitats. Different from results previously reported, our selective pressure estimation suggested that the genes related to photosynthesis (such as ycf2) were under positive selection at sites in the coding region.

scholarly journals Analysis of six chloroplast genomes provides insight into the evolution of Chrysosplenium (Saxifragaceae)

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhihua Wu ◽  
Rui Liao ◽  
Tiange Yang ◽  
Xiang Dong ◽  
Deqing Lan ◽  
...  
Keyword(s):  
Positive Selection ◽  
Selective Pressure ◽  
Phylogenetic Analyses ◽  
Genome Structure ◽  
Gc Content ◽  
Light Conditions ◽  
Low Light ◽  
Plant Adaptation ◽  
Chloroplast Genomes ◽  
Pressure Estimation

Abstract Background Chrysosplenium L. (Saxifragaceae) is a genus of plants widely distributed in Northern Hemisphere and usually found in moist, shaded valleys and mountain slopes. This genus is ideal for studying plant adaptation to low light conditions. Although some progress has been made in the systematics and biogeography of Chrysosplenium, its chloroplast genome evolution remains to be investigated. Results To fill this gap, we sequenced the chloroplast genomes of six Chrysosplenium species and analyzed their genome structure, GC content, and nucleotide diversity. Moreover, we performed a phylogenetic analysis and calculated non-synonymous (Ka) /synonymous (Ks) substitution ratios using the combined protein-coding genes of 29 species within Saxifragales and two additional species as outgroups, as well as a pair-wise estimation for each gene within Chrysosplenium. Compared with the outgroups in Saxifragaceae, the six Chrysosplenium chloroplast genomes had lower GC contents; they also had conserved boundary regions and gene contents, as only the rpl32 gene was lost in four of the Chrysosplenium chloroplast genomes. Phylogenetic analyses suggested that the Chrysosplenium separated to two major clades (the opposite group and the alternate group). The selection pressure estimation (Ka/Ks ratios) of genes in the Chrysosplenium species showed that matK and ycf2 were subjected to positive selection. Conclusion This study provides genetic resources for exploring the phylogeny of Chrysosplenium and sheds light on plant adaptation to low light conditions. The lower average GC content and the lacking gene of rpl32 indicated selective pressure in their unique habitats. Different from results previously reported, our selective pressure estimation suggested that the genes related to photosynthesis (such as ycf2) were under positive selection at sites in the coding region.

scholarly journals Analysis of Six Chloroplast Genomes Provides Insight into the Evolution of Chrysosplenium (Saxifragaceae)

2020 ◽  
Author(s):  
Zhihua Wu ◽  
Rui Liao ◽  
Tiange Yang ◽  
Xiang Dong ◽  
Deqing Lan ◽  
...  
Keyword(s):  
Selective Pressure ◽  
Phylogenetic Analyses ◽  
Genome Structure ◽  
Gc Content ◽  
Light Conditions ◽  
Coding Region ◽  
Low Light ◽  
Additional Species ◽  
Plant Adaptation ◽  
Chloroplast Genomes

Abstract Background Chrysosplenium L. (Saxifragaceae) is a genus of plants widely distributed in China and usually found in moist, shaded valleys and mountain slopes. This genus is ideal for studying plant adaptation to low-light conditions. Although some progress has been made in the systematics and biogeography of Chrysosplenium, its chloroplast genome evolution remains to be investigated. Results To fill this gap, we sequenced the chloroplast genomes of six Chrysosplenium species and analyzed their genome structure, GC content, and nucleotide diversity. Moreover, we performed a phylogenetic analysis and calculated non-synonymous (Ka)/synonymous (Ks) substitution ratios using the combined protein-coding genes of 29 species within Saxifragales and two additional species as outgroups, as well as a pair-wise estimation for each gene within Chrysosplenium. Compared with the outgroups in Saxifragaceae, the six Chrysosplenium chloroplast genomes had lower GC contents; they also had conserved boundary regions and gene contents, as only the rpl32 gene was lost in four of the Chrysosplenium chloroplast genomes. Phylogenetic analyses suggested that the Chrysosplenium separated to two major clades (the opposite group and the alternate group). The pair-wise Ka/Ks ratios of genes in the Chrysosplenium species showed that matK and ycf2 were subjected to relatively relaxed selection. Conclusion This study provides genetic resources for exploring the phylogeny of Chrysosplenium and sheds light on plant adaptation to low-light conditions. The lower average GC content and the lacking gene of rpl32 indicating selective pressure in their unique habitats. Different from results previously reported, our selective pressure estimation suggested that the genes related to photosynthesis (such as ycf2) were under positive selection at sites in the coding region.

scholarly journals Analysis of Six Chloroplast Genomes Provides Insight into the Evolution of Chrysosplenium (Saxifragaceae)

2020 ◽  
Author(s):  
Zhihua Wu ◽  
Rui Liao ◽  
Tiange Yang ◽  
Xiang Dong ◽  
Deqing Lan ◽  
...  
Keyword(s):  
Positive Selection ◽  
Selective Pressure ◽  
Phylogenetic Analyses ◽  
Genome Structure ◽  
Gc Content ◽  
Light Conditions ◽  
Low Light ◽  
Plant Adaptation ◽  
Chloroplast Genomes ◽  
Pressure Estimation

Abstract Background: Chrysosplenium L. (Saxifragaceae) is a genus of plants widely distributed in Northern Hemisphere and usually found in moist, shaded valleys and mountain slopes. This genus is ideal for studying plant adaptation to low-light conditions. Although some progress has been made in the systematics and biogeography of Chrysosplenium, its chloroplast genome evolution remains to be investigated. Results: To fill this gap, we sequenced the chloroplast genomes of six Chrysosplenium species and analyzed their genome structure, GC content, and nucleotide diversity. Moreover, we performed a phylogenetic analysis and calculated non-synonymous (Ka) /synonymous (Ks) substitution ratios using the combined protein-coding genes of 29 species within Saxifragales and two additional species as outgroups, as well as a pair-wise estimation for each gene within Chrysosplenium. Compared with the outgroups in Saxifragaceae, the six Chrysosplenium chloroplast genomes had lower GC contents; they also had conserved boundary regions and gene contents, as only the rpl32 gene was lost in four of the Chrysosplenium chloroplast genomes. Phylogenetic analyses suggested that the Chrysosplenium separated to two major clades (the opposite group and the alternate group). The selection pressure estimation (Ka/Ks ratios) of genes in the Chrysosplenium species showed that matK and ycf2 were subjected to positive selection.Conclusion: This study provides genetic resources for exploring the phylogeny of Chrysosplenium and sheds light on plant adaptation to low-light conditions. The lower average GC content and the lacking gene of rpl32 indicated selective pressure in their unique habitats. Different from results previously reported, our selective pressure estimation suggested that the genes related to photosynthesis (such as ycf2) were under positive selection at sites in the coding region.

scholarly journals Analysis of Six Chloroplast Genomes Provides Insight into the Evolution of Chrysosplenium (Saxifragaceae)

2020 ◽  
Author(s):  
Zhihua Wu ◽  
Rui Liao ◽  
Tiange Yang ◽  
Xiang Dong ◽  
Deqing Lan ◽  
...  
Keyword(s):  
Positive Selection ◽  
Selective Pressure ◽  
Phylogenetic Analyses ◽  
Genome Structure ◽  
Gc Content ◽  
Light Conditions ◽  
Low Light ◽  
Plant Adaptation ◽  
Chloroplast Genomes ◽  
Pressure Estimation

Abstract Background: Chrysosplenium L. (Saxifragaceae) is a genus of plants widely distributed in Northern Hemisphere and usually found in moist, shaded valleys and mountain slopes. This genus is ideal for studying plant adaptation to low light conditions. Although some progress has been made in the systematics and biogeography of Chrysosplenium, its chloroplast genome evolution remains to be investigated. Results: To fill this gap, we sequenced the chloroplast genomes of six Chrysosplenium species and analyzed their genome structure, GC content, and nucleotide diversity. Moreover, we performed a phylogenetic analysis and calculated non-synonymous (Ka) /synonymous (Ks) substitution ratios using the combined protein-coding genes of 29 species within Saxifragales and two additional species as outgroups, as well as a pair-wise estimation for each gene within Chrysosplenium. Compared with the outgroups in Saxifragaceae, the six Chrysosplenium chloroplast genomes had lower GC contents; they also had conserved boundary regions and gene contents, as only the rpl32 gene was lost in four of the Chrysosplenium chloroplast genomes. Phylogenetic analyses suggested that the Chrysosplenium separated to two major clades (the opposite group and the alternate group). The selection pressure estimation (Ka/Ks ratios) of genes in the Chrysosplenium species showed that matK and ycf2 were subjected to positive selection.Conclusion: This study provides genetic resources for exploring the phylogeny of Chrysosplenium and sheds light on plant adaptation to low light conditions. The lower average GC content and the lacking gene of rpl32 indicated selective pressure in their unique habitats. Different from results previously reported, our selective pressure estimation suggested that the genes related to photosynthesis (such as ycf2) were under positive selection at sites in the coding region.

scholarly journals Analysis of Six Chloroplast Genomes Provides Insight into the Evolution of Chrysosplenium (Saxifragaceae)

2020 ◽  
Author(s):  
Zhihua Wu ◽  
Rui Liao ◽  
Tiange Yang ◽  
Xiang Dong ◽  
Deqing Lan ◽  
...  
Keyword(s):  
Selective Pressure ◽  
Phylogenetic Analyses ◽  
Genome Structure ◽  
Gc Content ◽  
Light Conditions ◽  
Coding Region ◽  
Low Light ◽  
Plant Adaptation ◽  
Chloroplast Genomes ◽  
Pressure Estimation

Abstract Background: Chrysosplenium L. (Saxifragaceae) is a genus of plants widely distributed in Northern Hemisphere and usually found in moist, shaded valleys and mountain slopes. This genus is ideal for studying plant adaptation to low-light conditions. Although some progress has been made in the systematics and biogeography of Chrysosplenium , its chloroplast genome evolution remains to be investigated.Results: To fill this gap, we sequenced the chloroplast genomes of six Chrysosplenium species and analyzed their genome structure, GC content, and nucleotide diversity. Moreover, we performed a phylogenetic analysis and calculated non-synonymous (Ka) /synonymous (Ks) substitution ratios using the combined protein-coding genes of 29 species within Saxifragales and two additional species as outgroups, as well as a pair-wise estimation for each gene within Chrysosplenium . Compared with the outgroups in Saxifragaceae, the six Chrysosplenium chloroplast genomes had lower GC contents; they also had conserved boundary regions and gene contents, as only the rpl32 gene was lost in four of the Chrysosplenium chloroplast genomes. Phylogenetic analyses suggested that the Chrysosplenium separated to two major clades (the opposite group and the alternate group). The selection pressure estimation (Ka/Ks ratios) of genes in the Chrysosplenium species showed that matK and ycf2 were subjected to positive selection.Conclusion: This study provides genetic resources for exploring the phylogeny of Chrysosplenium and sheds light on plant adaptation to low-light conditions. The lower average GC content and the lacking gene of rpl32 indicated selective pressure in their unique habitats. Different from results previously reported, our selective pressure estimation suggested that the genes related to photosynthesis (such as ycf2 ) were under positive selection at sites in the coding region.

scholarly journals Neural network aided approximation and parameter inference of non-Markovian models of gene expression

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qingchao Jiang ◽  
Xiaoming Fu ◽  
Shifu Yan ◽  
Runlai Li ◽  
Wenli Du ◽  
...  
Keyword(s):  
Neural Network ◽  
Stochastic Dynamics ◽  
Stochastic Simulations ◽  
Parameter Inference ◽  
Biochemical Processes ◽  
Markovian Models ◽  
The Neural Network ◽  
Large Numbers ◽  
Small Set ◽  
Noisy Measurements

AbstractNon-Markovian models of stochastic biochemical kinetics often incorporate explicit time delays to effectively model large numbers of intermediate biochemical processes. Analysis and simulation of these models, as well as the inference of their parameters from data, are fraught with difficulties because the dynamics depends on the system’s history. Here we use an artificial neural network to approximate the time-dependent distributions of non-Markovian models by the solutions of much simpler time-inhomogeneous Markovian models; the approximation does not increase the dimensionality of the model and simultaneously leads to inference of the kinetic parameters. The training of the neural network uses a relatively small set of noisy measurements generated by experimental data or stochastic simulations of the non-Markovian model. We show using a variety of models, where the delays stem from transcriptional processes and feedback control, that the Markovian models learnt by the neural network accurately reflect the stochastic dynamics across parameter space.

scholarly journals Epidemiological and phylogenetic analysis reveals Flavobacteriaceae as potential ancestral source of tigecycline resistance gene tet(X)

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Rong Zhang ◽  
Ning Dong ◽  
Zhangqi Shen ◽  
Yu Zeng ◽  
Jiauyue Lu ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Resistance Gene ◽  
Gc Content ◽  
Zhejiang Province ◽  
Bacterial Strains ◽  
Gram Negative ◽  
E Coli ◽  
Transmission Mechanisms ◽  
Low Prevalence ◽  
Potential Origin

Abstract Emergence of tigecycline-resistance tet(X) gene orthologues rendered tigecycline ineffective as last-resort antibiotic. To understand the potential origin and transmission mechanisms of these genes, we survey the prevalence of tet(X) and its orthologues in 2997 clinical E. coli and K. pneumoniae isolates collected nationwide in China with results showing very low prevalence on these two types of strains, 0.32% and 0%, respectively. Further surveillance of tet(X) orthologues in 3692 different clinical Gram-negative bacterial strains collected during 1994–2019 in hospitals in Zhejiang province, China reveals 106 (2.7%) tet(X)-bearing strains with Flavobacteriaceae being the dominant (97/376, 25.8%) bacteria. In addition, tet(X)s are found to be predominantly located on the chromosomes of Flavobacteriaceae and share similar GC-content as Flavobacteriaceae. It also further evolves into different orthologues and transmits among different species. Data from this work suggest that Flavobacteriaceae could be the potential ancestral source of the tigecycline resistance gene tet(X).

scholarly journals Coupling Between Protein Level Selection and Codon Usage Optimization in the Evolution of Bacteria and Archaea

mBio ◽  
2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Wenqi Ran ◽  
David M. Kristensen ◽  
Eugene V. Koonin
Keyword(s):  
Codon Usage ◽  
Protein Level ◽  
Codon Usage Bias ◽  
Protein Sequence ◽  
Gc Content ◽  
Protein Sequences ◽  
Microbial Evolution ◽  
Fine Tuning ◽  
Selection For ◽  
Genomic Gc Content

ABSTRACT The relationship between the selection affecting codon usage and selection on protein sequences of orthologous genes in diverse groups of bacteria and archaea was examined by using the Alignable Tight Genome Clusters database of prokaryote genomes. The codon usage bias is generally low, with 57.5% of the gene-specific optimal codon frequencies (F opt ) being below 0.55. This apparent weak selection on codon usage contrasts with the strong purifying selection on amino acid sequences, with 65.8% of the gene-specific dN/dS ratios being below 0.1. For most of the genomes compared, a limited but statistically significant negative correlation between F opt and dN/dS was observed, which is indicative of a link between selection on protein sequence and selection on codon usage. The strength of the coupling between the protein level selection and codon usage bias showed a strong positive correlation with the genomic GC content. Combined with previous observations on the selection for GC-rich codons in bacteria and archaea with GC-rich genomes, these findings suggest that selection for translational fine-tuning could be an important factor in microbial evolution that drives the evolution of genome GC content away from mutational equilibrium. This type of selection is particularly pronounced in slowly evolving, “high-status” genes. A significantly stronger link between the two aspects of selection is observed in free-living bacteria than in parasitic bacteria and in genes encoding metabolic enzymes and transporters than in informational genes. These differences might reflect the special importance of translational fine-tuning for the adaptability of gene expression to environmental changes. The results of this work establish the coupling between protein level selection and selection for translational optimization as a distinct and potentially important factor in microbial evolution. IMPORTANCE Selection affects the evolution of microbial genomes at many levels, including both the structure of proteins and the regulation of their production. Here we demonstrate the coupling between the selection on protein sequences and the optimization of codon usage in a broad range of bacteria and archaea. The strength of this coupling varies over a wide range and strongly and positively correlates with the genomic GC content. The cause(s) of the evolution of high GC content is a long-standing open question, given the universal mutational bias toward AT. We propose that optimization of codon usage could be one of the key factors that determine the evolution of GC-rich genomes. This work establishes the coupling between selection at the level of protein sequence and at the level of codon choice optimization as a distinct aspect of genome evolution.

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