Ontology highlight
ABSTRACT:
PROVIDER: PRJNA558233 | ENA |
REPOSITORIES: ENA
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Project description:Plasmids are extrachromosomal genetic elements commonly found in bacteria. Plasmids are known to fuel bacterial evolution through horizontal gene transfer (HGT), but recent analyses indicate that they can also promote intragenomic adaptations. However, the role of plasmids as catalysts of bacterial evolution beyond HGT remains poorly explored. In this study, we investigate the impact of a widespread conjugative plasmid, pOXA-48, on the evolution of various multidrug-resistant clinical enterobacteria. Combining experimental and within-patient evolution analyses, we unveil that plasmid pOXA-48 promotes bacterial evolution through the transposition of plasmid-encoded IS1 elements. Specifically, IS1-mediated gene inactivations expedite the adaptation rate of clinical strains in vitro and foster within-patient adaptation in the gut. We decipher the mechanism underlying the plasmid-mediated surge in IS1 transposition, revealing a negative feedback loop regulated by the genomic copy number of IS1. Given the overrepresentation of IS elements in bacterial plasmids, our findings propose that plasmid-mediated IS transposition represents a crucial mechanism for swift bacterial adaptation.
2024-07-16 | GSE255663 | GEO
Project description:As compared to Eukaryotes, Bacteria have a reduced tRNA gene set encoding between 30 and 220 tRNAs, which are thought to act in concert for the maintenance of gene translation. Here we show that in some bacteria the tRNA gene set may be partitioned in a housekeeping sub-set that sustains translation, and an inducible one that is generally silent but can be largely induced to provide functionality under particular conditions. In the model cyanobacterium Anabaena sp. PCC 7120, the inducible set forms an operon encoding 23 functional tRNAs. Transcription of these tRNAs is induced by translation stress, i.e. by insults that impair translation, including antibiotics that target the ribosome. The operon is co-regulated with genes encoding proteins like the tRNA ligase RtcB and the stress-specific protein DpsA, probably involved in a response directed to protect the cell and recover translation. Common regulation suggests participation of operonic tRNAs in this response, although mechanistic issues remain to be determined. Similar long tRNA gene operons were found in species across major bacterial phyla and are shown to be distinct in many aspects from other operons that evolved by gene accretion.
2021-07-14 | GSE159215 | GEO
Project description:We used microarrays to study the evolution of gene expression in two bacterial ecotypes that coexisted for more than 35000 generations of experimental evolution in an extremely simple environment
2012-01-01 | GSE30639 | GEO
Project description:The commercial tomato cultivar âKommeetâ was grafted either onto the tomato cultivar âMoneymakerâ (sub-optimal temperature sensitive) or onto the line accession âLA 1777â of the wild tomato species S. habrochaites (sub-optimal temperature tolerant) in a heated glasshouse. Grafted tomato plants were grown in a nutrient film technique system with re-circulating nutrient solution resulting in different root temperature (T), which was either optimal (day and night 25±0.6°C) or sub-optimal (day and night 15±0.4°C) while the air T was optimal (day and night 25±0.6°C) throughout the experimental procedure. After 30 days of differential treatment, differences in growth, physiology, and global gene expression in roots and leaves of all grafting and T combinations were investigated.
2017-06-27 | E-MTAB-4986 | biostudies-arrayexpress
Project description:Mature tRNA pools were measured using an adaptation of Y-shaped Adapter-ligated MAture tRNA sequencing (YAMAT-seq) (Shigematsu et al., 2017) in nine strains derived from the model bacterium, Pseudomonas fluorescens SBW25. The aim of the experiment was to determine the effect on the mature tRNA pool of (i) removing the single-copy serCGA gene by genetic engineering, and (ii) duplicating the serTGA gene during a subsequent, compensatory evolution experiment. We found that (i) results in the loss of tRNA-Ser(CGA) from the mature tRNA pool, and (ii) results in a 2-fold higher expression of tRNA-Ser(UGA). tRNA-Ser(UGA) presumably substitutes for tRNA-Ser(CGA) by wobble base pairing to translate codon 5'-UCG-3'.
2020-11-02 | GSE144791 | GEO
Project description:Mature tRNA pools were measured using an adaptation of YAMAT-seq (Shigematsu et al., 2017; doi:10.1093/nar/gkx005 ) and further described in (Ayan et al., 2020; doi:10.7554/eLife.57947) in eight strains dervied from the model bacterium, Pseudomonas fluorescens SBW25. The aim of the experiment was to determine the effect on the mature tRNA pool of (i) removing multi-copy tRNA genes by genetic engineering, and (ii) duplicating tRNA genes during a subsequent, compensatory evolution experiment. We found that (i) results in a reduction in some tRNA isotypes in the mature tRNA pool, and (ii) results in an increase in a compensatory increase in their expression.
2022-12-02 | GSE196705 | GEO
Project description:Gene copy-number variation, which provides the raw material for the evolution of novel genes, is surprisingly widespread in natural populations. Experimental evolution studies have demonstrated an extremely high spontaneous rate of origin of gene duplications. When organisms are suboptimally adapted to their environment, gene duplication may compensate for reduced fitness by amplifying promiscuous activity of a gene, or increasing dosage of a suboptimal gene. The overarching goal of this study is to inverstigate whether CNVs constitute a common mechanism of adaptive genetic change during compensatory evolution and to further characterize the role of natural selection in dictating their evolutionary spread at a population-genomic level. Outcrossing populations of C. elegans with low fitness were evolved for >200 generations and the frequencies of CNVs in these populations were analyzed by oligonucleotide array comparative genome hybridization, quantitative PCR, and single-worm PCR. Multiple duplications and deletions were detected in intermediate to high frequencies and several lines of evidence suggest that the changes in frequency were adaptive. 1) Many copy-number changes reached high frequency, were near fixation, or were fixed in a short time. 2) Many independent duplications and deletions in high frequency harbor overlapping regions which likely include genes that are under selection for either higher or lower rates of expression. 3) The size spectrum of deuplications and deletions in the adaptive recovery populations is significantly larger than that of spontaneous copy-number variants in mutation accumulation experiments. This is expected if larger CNVs are more likely to encompass genes that are being selected for altered gene dosage. Out results validate the great potential borne by gene copy-number changes for compensatory evolution and adaptation. Experimental genome evolution of copy-number variants in 25 experimental lines compared to 5 ancestral control lines.
2015-04-15 | E-GEOD-67871 | biostudies-arrayexpress
Project description:Bacterial RNA has emerged as important activator of innate immune responses by stimulating the endosomal Toll-like receptors TLR7 and TLR8 in humans. Guanosine 2’-O-methylation at position 18 (Gm18) in bacterial tRNA was shown to antagonize tRNA induced TLR7/8 activation, giving rise to a potential role of this modification as immune escape mechanism. This modification also occurs in eukaryotic tRNA, yet a physiological immune function remains to be established. We therefore set out to investigate the physiological role of Gm18 in prokaryotic and eukaryotic microorganisms by using mutants deficient in the respective 2’-O-methyltransferase. In E. coli, lack of 2’-O-methyltransferase trmH enhanced immune stimulatory properties of both tRNA and whole cellular RNA. Yet, when using living microorganisms, trmH mutants did not differ from their wildtype counterparts in terms of immunostimulation although gene expression profiling demonstrated the induction of a TLR8/RNA dependent gene signature by E. coli in principle. In summary, the results demonstrate that Gm18 is a global immune inhibitory RNA modification across the kingdoms and contributes to RNA recognition by innate immune cells.
2019-03-15 | GSE125797 | GEO