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1.
Int J Mol Sci ; 22(4)2021 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-33671470

RESUMO

G-quadruplexes (G4s) are four-stranded helical structures that regulate several nuclear processes, including gene expression and telomere maintenance. We observed that G4s are located in GC-rich (euchromatin) regions and outside the fibrillarin-positive compartment of nucleoli. Genomic regions around G4s were preferentially H3K9 acetylated and H3K9 dimethylated, but H3K9me3 rarely decorated G4 structures. We additionally observed the variability in the number of G4s in selected human and mouse cell lines. We found the highest number of G4s in human embryonic stem cells. We observed the highest degree of colocalization between G4s and transcription factories, positive on the phosphorylated form of RNA polymerase II (RNAP II). Similarly, a high colocalization rate was between G4s and nuclear speckles, enriched in pre-mRNA splicing factor SC-35. PML bodies, the replication protein SMD1, and Cajal bodies colocalized with G4s to a lesser extent. Thus, G4 structures seem to appear mainly in nuclear compartments transcribed via RNAP II, and pre-mRNA is spliced via the SC-35 protein. However, α-amanitin, an inhibitor of RNAP II, did not affect colocalization between G4s and transcription factories as well as G4s and SC-35-positive domains. In addition, irradiation by γ-rays did not change a mutual link between G4s and DNA repair proteins (G4s/γH2AX, G4s/53BP1, and G4s/MDC1), accumulated into DNA damage foci. Described characteristics of G4s seem to be the manifestation of pronounced G4s stability that is likely maintained not only via a high-order organization of these structures but also by a specific histone signature, including H3K9me2, responsible for chromatin compaction.


Assuntos
Núcleo Celular/metabolismo , Quadruplex G , Histonas/metabolismo , Transcrição Genética , Acetilação , Animais , Composição de Bases/genética , Linhagem Celular , Nucléolo Celular/metabolismo , Cromatina/metabolismo , DNA/metabolismo , Reparo do DNA , Epigênese Genética , Humanos , Corpos de Inclusão/metabolismo , Metilação , Camundongos
2.
Gene ; 777: 145467, 2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33524519

RESUMO

The current research on Ephemeroptera is mainly based on its morphology, since only small numbers of mitogenomes have been reported. In this study, the mitogenomes of Epeorus carinatus (15,338 bp) and E. dayongensis (15,609 bp) were sequenced, annotated and compared to genome data from congeners. Both mitogenomes had 23 tRNA genes including standard 22 and one extra tRNAMet. The duplicated tRNAMet gene had been found in other heptageniid species except Paegniodes cupulatus, suggesting it could be used as a molecular synapomorphy for partial Heptageniidae. The phylogenetic analyses based on Bayesian Inference (BI) and Maximum Likelihood (ML) showed that Heptageniidae was monophyletic and the relationships among known Epeorus species were ((E. carinatus + E. herklotsi) + (E. dayongensis + E. sp. 1)), which implied the focal species E. carinatus and E. dayongensis should be grouped into different subgenera.


Assuntos
Ephemeroptera/genética , Genes Mitocondriais/genética , Genoma Mitocondrial/genética , Animais , Composição de Bases/genética , Sequência de Bases/genética , Ephemeroptera/classificação , Genômica/métodos , Filogenia , RNA de Transferência/genética
3.
Arch Virol ; 166(2): 651-654, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33387023

RESUMO

A novel lytic bacteriophage, Ralstonia phage RP13, was isolated from tomato fields in Pang Nga, Thailand. Electron microscopic observation showed it to have the features of a myovirus with a novel triangulation number (T = 21, dextro). The RP13 DNA appeared to be heavily modified. By applying RNA sequencing and RNA-sequence-mediated DNA sequencing, the whole genome of RP31 was determined to be 170,942 bp in length with a mean G+C content of 39.2%. A total of 277 ORFs were identified as structural, functional, or hypothetical genes in addition to four tRNA genes. Phylogenetic analysis suggested that RP13 is not closely related to any other known phages. Thus, we concluded that the RP13 is a novel phage infecting R. solanacearum strains and will be a useful biocontrol agent against bacterial wilt disease.


Assuntos
Bacteriófagos/genética , Genoma Viral/genética , Doenças das Plantas/microbiologia , Ralstonia solanacearum/virologia , Composição de Bases/genética , Genômica/métodos , Especificidade de Hospedeiro/genética , Lycopersicon esculentum/microbiologia , Fases de Leitura Aberta/genética , Filogenia , RNA de Transferência/genética , Tailândia
4.
Arch Virol ; 166(2): 601-606, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33392816

RESUMO

Bacteriophage 8P was isolated with a Pseudomonas stutzeri strain isolated from an oil reservoir as its host bacterium. The phage genome comprises 63,753 base pairs with a G+C content of 64.35. The phage encodes 63 predicted proteins, and 27 of them were functionally assigned. No tRNA genes were found. Comparative genomics analysis showed that 8P displayed some relatedness to F116-like phages (78% identity, 20% query coverage). The genome has very low sequence similarity to the other phage genomes in the GenBank database and Viral Sequence Database. Based on whole-genome analysis and transmission electron microscopy imaging, 8P is proposed to be a member of a new species in the genus Hollowayvirus, family Podoviridae.


Assuntos
Bacteriófagos/genética , Bacteriófagos/isolamento & purificação , Fagos de Pseudomonas/genética , Fagos de Pseudomonas/isolamento & purificação , Pseudomonas stutzeri/virologia , Composição de Bases/genética , DNA Viral/genética , Genoma Viral/genética , Genômica/métodos , Especificidade de Hospedeiro/genética , Filogenia , Podoviridae/genética , Podoviridae/isolamento & purificação , Análise de Sequência de DNA/métodos
5.
Mol Phylogenet Evol ; 156: 107045, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33352317

RESUMO

Ladybirds (family Coccinellidae) are one of the most diverse groups of beetles and globally comprise over 6000 species. Despite their scientific and economic significance, the taxonomy of Coccinellidae remains unstable, and we still know little about their evolutionary history. By using a small number of genes, previous phylogenetic analyses have not reliably resolved the relationships among major ladybird lineages. In this study, we sequenced 94 nuclear protein-coding genes for 214 species of Coccinellidae and 14 outgroups, covering 90 genera and 35 tribes. We found that nucleotide compositional heterogeneity is present among ladybird tribes so that phylogenetic inference at the amino acid level is more reliable than at the DNA level. Based on the maximum likelihood analyses of the amino acid dataset, we recognize three subfamilies in Coccinellidae: Microweiseinae, Monocoryninae stat. nov., and Coccinellinae. The subfamily relationships are strongly supported as (Microweiseinae, (Monocoryninae stat. nov., Coccinellinae)). The tribes of ladybirds are mostly monophyletic, except Ortaliini, Sticholotidini, Scymnini, and Coccidulini. The phylogenetic relationships among tribes of Coccinellinae are still not well resolved, with many nodes weakly supported. Our divergence time analysis suggests that the crown group of extant lady beetles arose in the Early Cretaceous ~ 143 million years ago (Mya) and experienced a rapid diversification during the Late Cretaceous (120-70 Mya). We hypothesize that the boom of angiosperms in the Late Cretaceous promoted the diversification of herbivorous Sternorrhyncha insects, especially aphids, which in turn drove the rapid radiation of predatory lady beetles. In summary, our work provides a comprehensive time-calibrated phylogeny of Coccinellidae that provides a sound framework for revising their classification and understanding the origin of their biodiversity.


Assuntos
Besouros/classificação , Besouros/genética , Genes de Insetos , Filogenia , Aminoácidos/genética , Animais , Composição de Bases/genética , Códon/genética , Nucleotídeos/genética , Fatores de Tempo
6.
Arch Virol ; 166(2): 639-643, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33315144

RESUMO

We present the complete genome sequence of bovine alphaherpesvirus 2 (BoHV-2), a member of the family Herpesviridae, subfamily Alphaherpesvirinae, genus Simplexvirus. BoHV-2 is the causative agent of bovine ulcerative mammillitis (bovine herpes mammillitis) and pseudo-lumpy skin disease. The genomic architecture of BoHV-2 is typical of most simplexvirus genomes and congruent with that of human alphaherpesvirus 1 (HHV-1). The genome comprises a total of 131,245 base pairs and has an overall G+C content of 64.9 mol%. A total of 75 open reading frames are predicted. The gene repertoire of BoHV-2 is analogous to that of HHV-1, although the coding region of US12 is missing. A phylogenetic analysis supported BoHV-2 as a member of the genus Simplexvirus.


Assuntos
DNA Viral/genética , Genoma Viral/genética , Herpesvirus Bovino 2/genética , Animais , Composição de Bases/genética , Bovinos , Doenças dos Bovinos/virologia , Herpesvirus Bovino 1/genética , Fases de Leitura Aberta/genética , Filogenia
7.
Nucleic Acids Res ; 48(18): 10353-10367, 2020 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-32926139

RESUMO

The vast majority of the genome is transcribed by RNA polymerases. G+C-rich regions of the chromosomes and negative superhelicity can promote the invasion of the DNA by RNA to form R-loops, which have been shown to block DNA replication and promote genome instability. However, it is unclear whether the R-loops themselves are sufficient to cause this instability or if additional factors are required. We have investigated replisome collisions with transcription complexes and R-loops using a reconstituted bacterial DNA replication system. RNA polymerase transcription complexes co-directionally oriented with the replication fork were transient blockages, whereas those oriented head-on were severe, stable blockages. On the other hand, replisomes easily bypassed R-loops on either template strand. Replication encounters with R-loops on the leading-strand template (co-directional) resulted in gaps in the nascent leading strand, whereas lagging-strand template R-loops (head-on) had little impact on replication fork progression. We conclude that whereas R-loops alone can act as transient replication blocks, most genome-destabilizing replication fork stalling likely occurs because of proteins bound to the R-loops.


Assuntos
Replicação do DNA/genética , Proteínas de Ligação a DNA/genética , Estruturas R-Loop/genética , Transcrição Genética , Composição de Bases/genética , Estruturas Cromossômicas/genética , Cromossomos/genética , DNA Helicases/genética , Reparo do DNA/genética , Escherichia coli/genética , Instabilidade Genômica/genética
8.
PLoS One ; 15(9): e0233197, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32946445

RESUMO

Levels of protein translation by ribosomes are governed both by features of the translation machinery as well as sequence properties of the mRNAs themselves. We focus here on a striking three-nucleotide periodicity, characterized by overrepresentation of GCN codons and underrepresentation of G at the second position of codons, that is observed in Open Reading Frames (ORFs) of mRNAs. Our examination of mRNA sequences in Saccharomyces cerevisiae revealed that this periodicity is particularly pronounced in the initial codons-the ramp region-of ORFs of genes with high protein expression. It is also found in mRNA sequences immediately following non-standard AUG start sites, located upstream or downstream of the standard annotated start sites of genes. To explore the possible influences of the ramp GCN periodicity on translation efficiency, we tested edited ramps with accentuated or depressed periodicity in two test genes, SKN7 and HMT1. Greater conformance to (GCN)n was found to significantly depress translation, whereas disrupting conformance had neutral or positive effects on translation. Our recent Molecular Dynamics analysis of a subsystem of translocating ribosomes in yeast revealed an interaction surface that H-bonds to the +1 codon that is about to enter the ribosome decoding center A site. The surface, comprised of 16S/18S rRNA C1054 and A1196 (E. coli numbering) and R146 of ribosomal protein Rps3, preferentially interacts with GCN codons, and we hypothesize that modulation of this mRNA-ribosome interaction may underlie GCN-mediated regulation of protein translation. Integration of our expression studies with large-scale reporter studies of ramp sequence variants suggests a model in which the C1054-A1196-R146 (CAR) interaction surface can act as both an accelerator and braking system for ribosome translation.


Assuntos
Códon de Iniciação/genética , Biossíntese de Proteínas/genética , Ribossomos/metabolismo , Saccharomyces cerevisiae/genética , Composição de Bases/genética , Códon de Iniciação/metabolismo , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Simulação de Dinâmica Molecular , Fases de Leitura Aberta/genética , Proteína-Arginina N-Metiltransferases/biossíntese , Proteína-Arginina N-Metiltransferases/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Repressoras/biossíntese , Proteínas Repressoras/genética , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/biossíntese , Proteínas de Saccharomyces cerevisiae/genética , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética
9.
Nat Commun ; 11(1): 4028, 2020 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-32788591

RESUMO

Changes in atmospheric CO2 concentration have played a central role in algal and plant adaptation and evolution. The commercially important red algal genus, Pyropia (Bangiales) appears to have responded to inorganic carbon (Ci) availability by evolving alternating heteromorphic generations that occupy distinct habitats. The leafy gametophyte inhabits the intertidal zone that undergoes frequent emersion, whereas the sporophyte conchocelis bores into mollusk shells. Here, we analyze a high-quality genome assembly of Pyropia yezoensis to elucidate the interplay between Ci availability and life cycle evolution. We find horizontal gene transfers from bacteria and expansion of gene families (e.g. carbonic anhydrase, anti-oxidative related genes), many of which show gametophyte-specific expression or significant up-regulation in gametophyte in response to dehydration. In conchocelis, the release of HCO3- from shell promoted by carbonic anhydrase provides a source of Ci. This hypothesis is supported by the incorporation of 13C isotope by conchocelis when co-cultured with 13C-labeled CaCO3.


Assuntos
Carbono/metabolismo , Genoma , Rodófitas/genética , Rodófitas/metabolismo , Movimentos da Água , Exoesqueleto/química , Animais , Antioxidantes/farmacologia , Composição de Bases/genética , Evolução Biológica , Carbonato de Cálcio/metabolismo , Anidrases Carbônicas/genética , Anidrases Carbônicas/metabolismo , Núcleo Celular/genética , Dosagem de Genes , Perfilação da Expressão Gênica , Transferência Genética Horizontal/genética , Moluscos , Fotossíntese/efeitos dos fármacos , Ploidias , Rodófitas/efeitos dos fármacos , Superóxido Dismutase/genética , Transcrição Genética/efeitos dos fármacos
10.
Arch Microbiol ; 202(10): 2771-2778, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32737542

RESUMO

A bacterial strain designated NYYP31T was isolated from the leaves of an annual halophytes, Suaeda corniculata Bunge, collected from the southern edge of the Gurbantunggut desert, north-west China. Strain NYYP31T was Gram-staining negative, strictly aerobic, rod-shaped, non-motile, and non-spore-forming. Growth was observed at 4-42 °C, at pH 5.0-10.0, in the presence of up to 8% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences and coding sequences of 92 protein clusters showed that strain NYYP31T should be assigned to the genus Sphingobacterium. 16S rRNA gene sequence similarity analysis showed that strain NYYP31T was most closely related to the type strain of Sphingobacterium daejeonense (97.9%) and Sphingobacterium lactis (97.7%). The predominant isoprenoid quinone was MK-7. The major fatty acids were identified as iso-C15:0, iso-C17:0 3-OH and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c). The polar lipids were phosphatidylethanolamine, two unidentified phospholipids, three unidentified lipids, three unidentified amino phospholipids, and two unidentified glycolipids. The genomic DNA G + C content was 36.4 mol%. The average nucleotide identity (ANI) values for strain NYYP31T to the type strains of S. daejeonense and S. lactis were 77.9 and 74.1%, respectively, which were below the cut-off level (95-96%) for species delineation. Based on the above results, strain NYYP31T represents a novel species of the genus Sphingobacterium, for which the name Sphingobacterium endophyticum sp. nov. is proposed. The type strain is NYYP31T (= CGMCC 1.16979T = NBRC 114258T).


Assuntos
Chenopodiaceae/microbiologia , Plantas Tolerantes a Sal/microbiologia , Sphingobacterium/classificação , Sphingobacterium/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases/genética , China , DNA Bacteriano/genética , Endófitos/classificação , Endófitos/genética , Endófitos/isolamento & purificação , Hibridização de Ácido Nucleico , Fosfolipídeos/química , Filogenia , Folhas de Planta/microbiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Microbiologia do Solo , Sphingobacterium/genética , Vitamina K 2/química
11.
Arch Microbiol ; 202(10): 2849-2853, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32683476

RESUMO

Achromobacter xylosoxidans DN002 is capable of utilizing numerous aromatic hydrocarbons as sole carbon and energy resource. In this study, the whole genome of strain DN002 was sequenced and analyzed, which consisted of one circular chromosome of 5,943,204 bp and a 278,917 bp plasmid with an average GC content of 65.46 mol%, 5694 protein-coding genes, 13 rRNA genes and 57 tRNA genes. Analysis of cluster of orthologous group (COG) demonstrated that strain DN002 had remarkable gene abundance foramino acid transport and metabolism, transcription, inorganic ion transport and metabolism, energy production and conversion, and carbohydrate transport and metabolism. Genes related to biodegradation of aromatic hydrocarbons, chemotaxis and flagella were identified from the genome, which will advance our fundamental understanding the molecular mechanism for degradation and metabolizing of aromatic hydrocarbons.


Assuntos
Achromobacter denitrificans/genética , Achromobacter denitrificans/metabolismo , Genoma Bacteriano/genética , Hidrocarbonetos Aromáticos/metabolismo , Composição de Bases/genética , Sequência de Bases/genética , Biodegradação Ambiental , Metabolismo Energético/genética , Metabolismo Energético/fisiologia , Hidrocarbonetos/metabolismo , Plasmídeos/genética
12.
mSphere ; 5(3)2020 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-32581081

RESUMO

The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has motivated an intensive analysis of its molecular epidemiology following its worldwide spread. To understand the early evolutionary events following its emergence, a data set of 985 complete SARS-CoV-2 sequences was assembled. Variants showed a mean of 5.5 to 9.5 nucleotide differences from each other, consistent with a midrange coronavirus substitution rate of 3 × 10-4 substitutions/site/year. Almost one-half of sequence changes were C→U transitions, with an 8-fold base frequency normalized directional asymmetry between C→U and U→C substitutions. Elevated ratios were observed in other recently emerged coronaviruses (SARS-CoV, Middle East respiratory syndrome [MERS]-CoV), and decreasing ratios were observed in other human coronaviruses (HCoV-NL63, -OC43, -229E, and -HKU1) proportionate to their increasing divergence. C→U transitions underpinned almost one-half of the amino acid differences between SARS-CoV-2 variants and occurred preferentially in both 5' U/A and 3' U/A flanking sequence contexts comparable to favored motifs of human APOBEC3 proteins. Marked base asymmetries observed in nonpandemic human coronaviruses (U ≫ A > G ≫ C) and low G+C contents may represent long-term effects of prolonged C→U hypermutation in their hosts. The evidence that much of sequence change in SARS-CoV-2 and other coronaviruses may be driven by a host APOBEC-like editing process has profound implications for understanding their short- and long-term evolution. Repeated cycles of mutation and reversion in favored mutational hot spots and the widespread occurrence of amino acid changes with no adaptive value for the virus represent a quite different paradigm of virus sequence change from neutral and Darwinian evolutionary frameworks and are not incorporated by standard models used in molecular epidemiology investigations.IMPORTANCE The wealth of accurately curated sequence data for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), its long genome, and its low substitution rate provides a relatively blank canvas with which to investigate effects of mutational and editing processes imposed by the host cell. The finding that a large proportion of sequence change in SARS-CoV-2 in the initial months of the pandemic comprised C→U mutations in a host APOBEC-like context provides evidence for a potent host-driven antiviral editing mechanism against coronaviruses more often associated with antiretroviral defense. In evolutionary terms, the contribution of biased, convergent, and context-dependent mutations to sequence change in SARS-CoV-2 is substantial, and these processes are not incorporated by standard models used in molecular epidemiology investigations.


Assuntos
Betacoronavirus/genética , Citosina/análise , Genoma Viral/genética , Polimorfismo de Nucleotídeo Único/genética , Uracila/análise , Composição de Bases/genética , Sequência de Bases/genética , Infecções por Coronavirus/patologia , Citidina Desaminase/genética , Humanos , Coronavírus da Síndrome Respiratória do Oriente Médio/genética , Pandemias , Pneumonia Viral/patologia , Vírus da SARS/genética
13.
Arch Virol ; 165(8): 1929-1932, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32514690

RESUMO

Phages, viruses targeting bacteria, have potential therapeutic applications in the control of infections with antibiotic-resistant bacteria. In this study, an Enterobacter cloacae phage, Ec_L1, was isolated from sewage sludge samples collected from a hospital. The genome of phage Ec_L1 consists of 51,894 bp with 48.24% G+C content. Nineteen of the 85 putative proteins encoded by this phage have known functions, and no rRNA or tRNA genes were found. Comparative analysis of genome sequences suggested that phage Ec_L1 should be considered a member of the subfamily Tunavirinae, which includes T1-like phages. According to the International Committee on Taxonomy of Viruses (ICTV), phage Ec_L1 is the type member of the new genus "Eclunavirus", whose name was derived from Ec_L1.


Assuntos
Bacteriófagos/genética , Enterobacter cloacae/virologia , Genoma Viral/genética , Composição de Bases/genética , Fases de Leitura Aberta/genética , Análise de Sequência/métodos
14.
PLoS One ; 15(4): e0232167, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32353016

RESUMO

We examined seventy million well-characterized human mutations, and their impact on G+C-compositional dynamics, in order to understand the formation and maintenance of major genomic nucleotide sequence patterns. Among novel mutations, those that change a strong (S) base pair G:C/C:G to a weak (W) pair A:T/T:A occur at nearly twice the frequency of the opposite mutations. Such imbalance puts strong downward pressure on overall GC-content. However, along protracted paths to fixation, S→W mutations are much less likely to propagate than W→S mutations. The magnitude of relative propagation disadvantages for S→W mutations is inexplicable by any currently-accepted model. This fact forced us to re-examine the quantitative features of Biased Gene Conversion (BGC) theory. Revised parameters of BGC that, per average individual, convert 7-14 W base pairs into S pairs, would account for the S-content turnover differences between new and old mutations, and make BGC an instrumental force for nucleotide dynamics and evolution. BGC should thus be considered seriously in both theories and biomedical practice. In particular, BGC should be taken into account during allele imputations, where missing SNP alleles are computationally predicted based on the information about several neighboring alleles. Finally, we analyzed the effect of neighboring nucleotide context on the mutation frequencies, dynamics, and GC-composition turnover. For this purpose, we examined genomic regions having extremely biased nucleotide compositions (enriched for S-, W-, purine/pyrimidine strand asymmetry, or AC/GT-strand asymmetry). It was found that point mutations in these regions preferentially degrade the nucleotide inhomogeneities, decreasing the sequence biases. Degradation of sequence bias is highest for novel mutations, and considerably lower for older mutations (those widespread across populations). Besides BGC, there may be additional, still uncharacterized molecular mechanisms that either preserve genomic regions with biased nucleotide compositions from mutational degradation or fail to degrade such inhomogeneities in specific chromosomal regions.


Assuntos
Composição de Bases/genética , Conversão Gênica/genética , Genoma Humano/genética , Alelos , Evolução Molecular , Humanos , Taxa de Mutação , Mutação Puntual/genética , Polimorfismo de Nucleotídeo Único/genética
15.
Nat Commun ; 11(1): 2452, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32415210

RESUMO

Many bacteria can exchange genetic material through horizontal gene transfer (HGT) mediated by plasmids and plasmid-borne transposable elements. Here, we study the population structure and dynamics of over 10,000 bacterial plasmids, by quantifying their genetic similarities and reconstructing a network based on their shared k-mer content. We use a community detection algorithm to assign plasmids into cliques, which correlate with plasmid gene content, bacterial host range, GC content, and existing classifications based on replicon and mobility (MOB) types. Further analysis of plasmid population structure allows us to uncover candidates for yet undescribed replicon genes, and to identify transposable elements as the main drivers of HGT at broad phylogenetic scales. Our work illustrates the potential of network-based analyses of the bacterial 'mobilome' and opens up the prospect of a natural, exhaustive classification framework for bacterial plasmids.


Assuntos
Bactérias/genética , Redes Reguladoras de Genes , Plasmídeos/genética , Algoritmos , Composição de Bases/genética , Bases de Dados Genéticas , Transferência Genética Horizontal/genética , Genes Bacterianos , Filogenia , Replicon/genética
16.
BMC Evol Biol ; 20(1): 51, 2020 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-32375634

RESUMO

BACKGROUND: Raw second-generation (2G) lignocellulosic biomass materials have the potential for development into a sustainable and renewable source of energy. Poplar is regarded as a promising 2G material (P. davidiana Dode×P. bolleana Lauch, P. bolleana, P. davidiana, P. euphratica, et al). However, their large-scale commercialization still faces many obstacles. For example, drought prevents sufficient irrigation or rainfall, which can reduce soil moisture and eventually destroy the chloroplast, the plant photosynthetic organelle. Heterosis is widely used in the production of drought-tolerant materials, such as the superior clone "Shanxinyang" selected from the offspring of Populus davidiana Dode×Populus bolleana Lauch. Because it produces good wood and is easily genetically transformed, "Shanxinyang" has become a promising material for use in tree genetics. It is also one of the most abundant biofuel plants in northern China. Understanding the genetic features of chloroplasts, the cp transcriptome and physiology is crucial to elucidating the chloroplast drought-response model. RESULTS: In this study, the whole genome of "Shanxinyang" was sequenced. The chloroplast genome was assembled, and chloroplast structure was analysed and compared with that of other popular plants. Chloroplast transcriptome analysis was performed under drought conditions. The total length of the "Shanxinyang" chloroplast genome was 156,190 bp, the GC content was 36.75%, and the genome was composed of four typical areas (LSC, IRa, IRb, and SSC). A total of 114 simple repeats were detected in the chloroplast genome of "Shanxinyang". In cp transcriptome analysis, we found 161 up-regulated and 157 down-regulated genes under drought, and 9 cpDEGs was randomly selected to conduct reverse transcription (RT)-qPCR., in which the Log2 (fold change) was significantly consistent with the qPCR results. The analysis of chloroplast transcription under drought provided clues for understanding chloroplast function under drought. The phylogenetic position of "Shanxinyang" within Populus was analysed by using the chloroplast genome sequences of 23 Populus plants, showing that "Shanxinyang" belongs to Sect. Populus and is sister to Populus davidiana. Further, mVISTA analysis showed that the variation in non-coding (regulatory) regions was greater than that in coding regions, which suggests that further attention should be paid to the chloroplast in order to obtain new evolutionary or functional insights related to aspects of plant biology. CONCLUSIONS: Our findings indicate that complex prokaryotic genome regulation occurs when processing transcripts under drought stress. The results not only offer clues for understanding the chloroplast genome and transcription features in woody plants but also serve as a basis for future molecular studies on poplar species.


Assuntos
Cloroplastos/genética , Secas , Filogenia , Populus/classificação , Populus/genética , Transcriptoma/genética , Composição de Bases/genética , Sequência de Bases , Éxons/genética , Regulação da Expressão Gênica de Plantas , Genoma de Cloroplastos , Íntrons/genética , Sequências Repetidas Invertidas/genética , Anotação de Sequência Molecular
17.
Gene ; 747: 144673, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32304783

RESUMO

Krabbe disease is one of the rarest autosomal recessive disorders in human, caused by mutation in the GALC (ß-galactosylceramidase) gene, resulting in several mental and physical health issues. Due to its rarity and phenotypic heterogeneity, diagnosis rate of this disease is very low. This study generated information on the recessive allele frequency dynamics of GALC gene across 15 global populations, with the highest frequency detected in Druze (Israel) population and the lowest frequency in Turkey and the United States. The recessive allele would take more time period (about 24,975 years) to be completely removed from the population having the lowest frequency and vice versa. The codon usage patterns of four isoforms of GALC gene revealed that a few synonymous codons were used more frequently than others in the isoforms. The codon AGA (arginine) was found to be overrepresented in GALC gene, except for galactocerebrosidase isoform a precursor. Further, GALC gene showed low codon usage bias (CUB) as evident from high ENC values (55.7-58.2), with A/T ending codons more preferred to G/C ending codons. CUB analysis elucidated the dual role of mutational pressure (major role) and natural selection (minor role) in GALC gene evolution.


Assuntos
Uso do Códon/genética , Galactosilceramidase/genética , Frequência do Gene/genética , Leucodistrofia de Células Globoides/enzimologia , Leucodistrofia de Células Globoides/genética , Aminoácidos/genética , Composição de Bases/genética , Códon/genética , Evolução Molecular , Galactosilceramidase/metabolismo , Humanos , Filogenia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo
18.
Arch Microbiol ; 202(6): 1545-1549, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32246163

RESUMO

A bacterial strain, designated YIM 98839T, was isolated from the hypersaline sediment of Aiding Lake in Xinjiang province, North-West China. The strain was Gram-stain-positive, motile, aerobic, produced oval subterminal or central endospores in swollen sporangia. The whole-cell hydrolysates contain meso-diaminopimelic acid as the diagnostic cell-wall diamino acid. Galactose, fucose and ribose are the major whole-cell sugars. The phospholipids are diphosphatidylglycerol, phosphatidylglycerol and one unknown phospholipid. The predominant menaquinone is MK-7. The major fatty acids are anteiso-C15:0, anteiso-C17:0 and iso-C15:0. The DNA G + C content of the type strain is 37.0 mol%. Phylogenetic analysis indicated that the isolate belongs to the genus Oceanobacillus. However, it differed from its closest relative, Oceanobacillus limi H9BT in many physiological characteristics. Moreover, the DNA-DNA relatedness values between the novel isolate and the relative type strain was 20.2%. Based on comparative analysis of polyphasic taxonomic data, strain YIM 98839T represents a novel species of the genus Oceanobacillus, for which the name Oceanobacillus halotolerans sp. nov. is proposed. The type strain is YIM 98839T (= CGMCC 1.17002T = KCTC 43140T).


Assuntos
Bacillaceae/classificação , Bacillaceae/genética , Bacillaceae/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases/genética , Parede Celular/química , China , DNA Bacteriano/genética , Ácido Diaminopimélico/análise , Ácidos Graxos/análise , Lagos/microbiologia , Fosfolipídeos/análise , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
19.
Arch Microbiol ; 202(6): 1535-1543, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32236722

RESUMO

A Gram-stain-positive, aerobic, spore-forming actinobacterial strain, designated 160415T, was isolated from a surface soil sample, which was formed on basaltic parent material, collected from Samsun, Turkey. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 160415T clustered closely with species of the genus Nonomuraea, and showed the highest sequence similarity to Nonomuraea zeae NEAU-ND5T, Nonomuraea candida HMC10T and Nonomuraea turkmeniaca DSM 43926T with 99.1%, 98.9% and 98.7%, respectively. Chemotaxonomic properties including major menaquinones, diaminopimelic acid, sugar and phospholipid profiles also confirmed the affiliation of the strain to the genus Nonomuraea. The DNA G+C content of strain 160415T was 69.6 mol%. DNA-DNA hybridization and average nucleotide identity values between the strain and closely related type strains were less than the recommended cut-off values. On the basis of phylogenetic relationships, genotypic and phenotypic characterizations, strain 160415T represents a novel species of the genus Nonomuraea, for which the name Nonomuraea basaltis sp. nov. is proposed. The type strain is 160415T (= KCTC 39875T = DSM 104309T).


Assuntos
Actinobacteria , Actinobacteria/classificação , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Actinomycetales/genética , Técnicas de Tipagem Bacteriana , Composição de Bases/genética , DNA Bacteriano/genética , Ácidos Graxos/análise , Genoma Bacteriano/genética , Fosfolipídeos/análise , Filogenia , RNA Ribossômico 16S/genética , Sideróforos/análise , Sideróforos/metabolismo , Solo , Microbiologia do Solo , Turquia
20.
Arch Microbiol ; 202(6): 1529-1534, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32232517

RESUMO

A Gram-staining positive, motile, rod-shaped and subterminal endospore-forming bacterium, designated strain SYSU K30005T, was isolated from a soil sample collected from a karst cave in Libo county, Guizhou province, south-western China. Strain SYSU K30005T showed the highest 16S rRNA gene sequence similarity with Lysinibacillus fusiformis (98.6%) and Lysinibacillus sphaericus (98.2%). In phylogenetic tree, strain SYSU K30005T clade with the members of the genus Lysinibacillus. Based on the phylogenetic and 16S gene sequence result, strain SYSU K30005T was affiliated to the genus Lysinibacillus. The growth of SYSU K30005T was observed at 15-37 °C (optimum, 28 °C), pH 6.0-9.0 (optimum, pH 7.0) and in the presence of 0-4% (w/v) NaCl (optimum in 3.5% NaCl). Cell wall peptidoglycan type was A4α (Lys-Asp). The cell-wall sugars of SYSU K30005T were ribose, galactose and mannose and MK-7 was the only quinone. The fatty acids (> 5% of total fatty acids) were iso-C15:0, anteiso-C15:0, iso-C16:0 and iso-C17:0. The polar lipids profile included diphosphatidylglycerol, phosphatideylglycerol, phosphatidylethanolamine and an unidentified phospholipid. The genomic DNA G + C content was 37.2 mol%. The average nucleotide identity values between SYSU K30005T and its closest relatives were below the cut-off level (95-96%) for species delineation. The results support the conclusion that strain SYSU K30005T represents a novel species of the genus Lysinibacillus, for which we proposed the name Lysinibacillus cavernae sp. nov. The type strain is SYSU K30005T (= KCTC 43130T = CGMCC 1.17492T).


Assuntos
Bacillaceae/classificação , Bacillaceae/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases/genética , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/química , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Solo , Microbiologia do Solo
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