Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1092712 | ENA |
REPOSITORIES: ENA
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Project description:Several groups have shown that through evolution experiments, tolerance and resistance evolved rapidly under cyclic antibiotic treatment. In other words, intermittent antibiotic exposure performed in a typical adaptive laboratory evolution (ALE) experiments will “train” the bacteria to become tolerant/resistant to the drug. Although ALE has added new knowledge regarding the impact of varying treatment conditions on the evolution of tolerance/resistance, the role of some parameters such as population bottlenecks remains poorly understood. In this study, we employed ALE to investigate the evolution of methicillin-resistant S. aureus under repetitive daptomycin treatment using a modified protocol that incorporated population bottleneck following antibiotic exposure. We observed that although tolerance development is slower under bottlenecking conditions, the populations finally attained tolerance mutation in the yycH gene after twelve cycles of treatment. Extending the evolution experiment and changing the treatment scheme to a fast evolution protocol (treatment during exponential phase without bottlenecking) led to the emergence of daptomycin resistance (mutation in mprF gene). Through proteomics, we uncovered the differential adaptation strategies of these daptomycin tolerant and resistant MRSA strains, and how they respond differently to antibiotics compared to the ancestral wild-type.
2022-07-16 | PXD031078 | Pride
Project description:Several groups have shown that through evolution experiments, tolerance and resistance evolved rapidly under cyclic antibiotic treatment. In other words, intermittent antibiotic exposure performed in a typical adaptive laboratory evolution (ALE) experiments will “train” the bacteria to become tolerant/resistant to the drug. Using this experimental strategy, we performed in vitro laboratory evolution in MRSA using daptomycin, and mine novel daptomycin tolerance and resistance mutants, which were isolated at specific time points during the evolution experiments. Three daptomycin-tolerant isolates with different tolerance level were generated from our laboratory evolution (TOL2 and TOL5 with a mild-tolerance phenotype, and TOL6 with a high-tolerance phenotype). They all bear mutations at different genes, and have no increase in MIC towards daptomycin. Besides, we also isolated three daptomycin-resistant isolates (RES1, RES2, RES3) that have a single point mutation in the same gene, mprF, but at different locations, leading to an increased MIC towards daptomycin. Through proteomics, we uncovered the differential adaptation strategies of these daptomycin tolerant and resistant MRSA strains, and how they respond differently to antibiotics compared to the ancestral wild-type.
2022-07-14 | PXD026741 | Pride
Project description:Gene duplication and deletion are pivotal processes shaping the structural and functional repertoire of genomes, with implications for disease, adaptation and evolution. We employed an experimental evolution framework partnered with high-throughput genomics to assess the molecular and transcriptional characteristics of novel gene copy-number variants (CNVs) in Caenorhabditis elegans populations subjected to varying intensity of selection. Here, we report a direct spontaneous genome-wide rate of gene duplication of 2.9 × 10-5 /gene/generation in C. elegans, the highest for any species to date. The increase in average transcript abundance of new duplicates arising under minimal selection is significantly greater than two-fold compared to single-copies of the same gene, suggesting that genes in segmental duplications are frequently overactive at inception. The average increase in transcriptional activity of gene duplicates is greater in MA lines that passed through single individual bottlenecks than in MA lines with larger population bottlenecks. Furthermore, there is an inverse relationship between the ancestral transcription levels of newly originating gene duplicates and population size, with duplicate copies of highly expressed genes less likely to accumulate in larger populations. The results demonstrate that there is a fitness cost of superfluous gene expression and purifying selection against new gene duplicates. However, on average, duplications also provide a significant increase in gene expression that can facilitate adaptation to novel environmental challenges.
2018-04-07 | GSE112821 | GEO
Project description:Based on inheritance of acquired characteristics, Lamarckian theory of evolution explains the evolution of biological systems through epigenetics. In a previous study, we have shown how microbial evolution has resulted in a persistent reduction in expression after repeatedly selecting for the lowest PGAL1-YFP-expressing cells. Applying the ATAC-seq assay on samples collected from this 28-days evolution experiment, here we show how genome-wide chromatin compaction change during evolution under selection pressure. We found that the chromatin compaction was altered not only on GAL network genes directly impacted by the selection pressure, showing an example of non-genetic memory, but also at the whole genome level. The GAL network genes experienced chromatin compaction accompanying the reduction in PGAL1-YFP reporter expression; strikingly, the fraction of global genes with differentially compacted chromatin states accounted for about a quarter of the total genome. Moreover, some of the ATAC-seq peaks followed well-defined temporal dynamics. Comparing the peak’s intensity in consecutive days, we found most of the differential compaction to occur between days 0 and 3 when the selection pressure was first applied, and between days 7 and 10 when the pressure was lifted. Among the gene sets enriched for the differential compaction events, some had increased chromatin availability once selection pressure was applied and decreased availability after the pressure was lifted (or vice versa). These results intriguingly show that, despite the lack of targeted selection, transcriptional availability of a large fraction of the genome change in a very diverse manner during evolution and these changes can occur in a relatively short number of generations.
2022-09-13 | GSE205227 | GEO
Project description:High-altitude pulmonary hypertension (HAPH) is a severe and progressive disease caused by chronic hypoxia and subsequent pulmonary vascular remodeling. No cure is currently available owing to an incomplete understanding about vascular remodeling. It is believed that hypoxia-induced diseases can be prevented by treating hypoxia. Thus, this study aimed to determine whether daily short-duration reoxygenation at sea level attenuates pulmonary hypertension under high-altitude hypoxia. To this end, a simulated 5,000-m hypoxia rat model was used to evaluate the effect of short-duration reoxygenation. Results show that intermittent, not continuous, short-duration reoxygenation effectively attenuates hypoxia-induced pulmonary hypertension. The mechanisms underlining the protective effects involved that intermittent, short-duration reoxygenation prevented functional and structural remodeling of pulmonary arteries and proliferation, migration, and phenotypic conversion of pulmonary artery smooth muscle cells under hypoxia. The specific genes or potential molecular pathways responsible for mediating the protective effects were also characterised by RNA sequencing.This study is novel in revealing a new potential method in preventing high-altitude pulmonary hypertension. It gives insights into the selection and optimisation of oxygen supply schemes in high-altitude areas.
2020-11-06 | GSE160926 | GEO
Project description:MicroRNAs (miRNA) are small, endogenous RNAs that regulate the expression of mRNAs posttranscriptionally. Evolutionarily new miRNAs, like new protein-coding genes, are dominantly expressed in reproductive organs. To dissect the evolutionary dynamics of new miRNAs in Drosophila spp, we sequenced small RNAs from two species of Drosophila, including four samples from reproductive organs and one sample from imaginal discs / CNS. miRNA expression profile shows vast majority of new miRNAs are specifically expressed in testes and/or ovaries, suggesting a role of sexual selection for new miRNA evolution.
2013-12-31 | GSE48017 | GEO
Project description:Female Aedes aegypti mosquitoes impose a severe global public health burden as primary vectors of multiple viral and parasitic pathogens. Under optimal environmental conditions, Aedes aegypti females have access to human hosts that provide blood proteins for egg development, conspecific males that provide sperm for fertilization, and freshwater that serves as an egg-laying substrate suitable for offspring survival. As global temperatures rise, Aedes aegypti females are faced with climate challenges, like intense droughts and intermittent precipitation, which create unpredictable and suboptimal conditions for the egg-laying step of their reproductive cycle. Aedes aegypti mosquitoes nonetheless show remarkable reproductive resilience, but how they achieve this is unknown. Here we show that under drought-like conditions simulated in the laboratory, mated, blood-fed Aedes aegypti females carrying mature eggs retain them in their ovaries for extended periods, while maintaining the viability of these eggs until they can be deposited in freshwater. Using transcriptomic and proteomic profiling of Aedes aegypti ovaries, we identify two previously uncharacterized genes – here named tweedledee and tweedledum – that show ovary-enriched, temporally-restricted expression during egg retention. These genes are mosquito-specific, linked within a syntenic locus, and rapidly evolving under positive selection, raising the possibility that they serve an adaptive function. Using loss-of-function mutagenesis to disrupt both genes, we show that, tweedledee and tweedledum, which encode secreted proteins, are specifically required for extended retention of viable eggs, such as during intermittent precipitation or drought. These results highlight an elegant example of taxon-restricted genes at the heart of an important adaptation that equips Aedes aegypti females with “insurance” to, when contextually appropriate, flexibly extend their reproductive sequence without losing reproductive capacity, thus allowing this species to exploit diverse and unpredictable/chaotic/changing habitats.
2022-03-02 | PXD030925 | Pride
Project description:Evolutionary studies are often limited by missing data that are critical to understanding the history of selection. Selection experiments, which reproduce rapid evolution under controlled conditions, are excellent tools to study how genomes evolve under selection. Here we present a genomic dissection of the Longshanks selection experiment, in which mice were selectively bred over 20 generations for longer tibiae relative to body mass, resulting in 13% longer tibiae in two replicates. We synthesized evolutionary theory, genome sequences and molecular genetics to understand the selection response and found that it involved both polygenic adaptation and discrete loci of major effect, with the strongest loci likely to be selected in parallel between replicates. We show that selection may favor de-repression of bone growth through inactivating two limb enhancers of an inhibitor, Nkx3-2. Our integrative genomic analyses thus show that it is possible to connect individual base-pair changes to the overall selection response.
2019-07-09 | GSE121565 | GEO
Project description:Evolution of Pseudomonas sp. ADP under atrazine selection pressure
| PRJNA296545 | ENA
Project description:Genomic changes under rapid evolution: selection for parasitoid resistance
| PRJNA170455 | ENA