Escherichia coli K-12 strain:K12
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA769657 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Selection of drug-resistant mammalian cell mutants requires multiple drug exposures. Since cells in starting population could be genetically identical, selection of pre-existent mutations is unlikely. Therefore, adaptation must involve generation of drug-resistant mutations de-novo. Understanding how adaptive mutations are generated and protect cells is important for our knowledge of cancer biology and evolution. Here, we studied adaptation of cancer cells to topoisomerase (Top1) inhibitor irinotecan, which triggers DNA breaks, resulting in cytotoxicity. Resistance mechanism was based on gradual accumulation of recurrent mutations in non-coding DNA at sequence-specific Top1 cleavage sites. Repair of DSBs at these sites following initial irinotecan exposures created mutant sequences that were resistant to further Top1 cleavage. Therefore, by virtue of creating DNA breaks Top1 increases the rate of highly protective mutations specifically at such spots, thus explaining a puzzling need of dose escalation in resistance development.
2021-11-24 | GSE189366 | GEO
Project description:Long-term survivors of childhood cancer experience treatment-related cardiotoxicity among a broad spectrum of chronic health conditions, which may be further aggrevated by suboptimal life-course social/behavioral/environmental exposures. Epigenetic mechanisms, particularly DNA methylation (DNAm), provide a potential link through which these exposures become biologically embedded and subsequently influence long-term health outcomes. Epigenome-wide association studies (EWAS) identified DNAm signatures associated with both treatment effects as well as life-course exposures. In parallel, DNAm variations were also evaluated in relation to cardiometabolic risk factors, cardiovascular diseases, and other chronic health conditions, revealing individual CpG sites or genes/geomic regions where these CpGs reside linked to clinically relevant phenotypes. Together, these findings support DNAm as a molecular interface connecting diverse exposures to adverse health outcomes. In addition, epigenetic age acceleration, assessed using DNAm-based aging biomarkers, was observed among survivors exposed to cancer treatments. Epigenetic age acceleration mediated a substantial proportion of the associations between cancer treatment exposures and cardiometabolic risk factors or cardiovascular diseases, supporting accelerated biological aging as a key pathway linking cancer treatment to long-term morbidity. Lifestyle and health behaviors, as well as social vulnerability and psychosocial stress, were also associated with variations in epigenetic age acceleration, highlighting the potential modifiability of aging-related pathways in ameliorating late-effects among childhood cancer survivors. In conclusion, these findings establish DNAm—captured through EWAS signatures and epigenetic age acceleration—as central molecular mechanisms linking treatment effects and life-course exposures to cardiotoxicity along with other chronic health conditions in childhood cancer survivors. This integrative epigenetic framework supports the use of DNAm-based biomarkers for risk stratification and nominates modifiable pathways as potential intervention targets to improve long-term survivorship outcomes.
2026-01-13 | GSE314261 | GEO
Project description:Strength of selection pressure is an important parameter contributing to the complexity of antibiotic resistance evolution
| PRJNA248369 | ENA
Project description:This study demonstrates simulated microgravity effects on E. coli K 12 MG1655 when grown on LB medium supplemented with glycerol. The results imply that E. coli readily reprograms itself to combat the multiple stresses imposed due to microgravity. Under these conditions it survives by upregulating oxidative stress protecting genes and simultaneously down regulating the membrane transporters and synthases to maintain cell homeostasis.
2012-09-06 | GSE40648 | GEO
Project description:Ten populations were evolved for 6,000 generations. Five had strong selection for sporulation, imposed partially by their cultivation in sporulation-inducing medium, while the other five populations had relaxed selection for sporulation, by cultivating them in sporulation-repressing medium. Batch cultures were diluted 1:100 daily for approximately 892 days. In the five populations with relaxed selection for sporulation, sporulation ability was eventually lost. Keywords: comparative genome hybridization and transcriptome divergence
2008-01-01 | GSE4469 | GEO
Project description:Adaptation of Escherichia coli to intracellular lifestyle
| PRJNA304679 | ENA
Project description:This study demonstrates simulated microgravity effects on E. coli K 12 MG1655 when grown on LB medium supplemented with glycerol. The results imply that E. coli readily reprograms itself to combat the multiple stresses imposed due to microgravity. Under these conditions it survives by upregulating oxidative stress protecting genes and simultaneously down regulating the membrane transporters and synthases to maintain cell homeostasis. In this study, a clinostat that mimics microgravity conditions was used to investigate the effects of microgravity on E. coli grown in LB medium supplemented with glycerol to monitor the effects on growth and global gene expression using Affymetrix DNA microarrays.
2012-09-06 | E-GEOD-40648 | biostudies-arrayexpress
Project description:Hybrid progeny can enjoy increased fitness and stress tolerance relative to their ancestral species, a phenomenon known as hybrid vigor. Though this phenomenon has been documented throughout the Eukarya, evolution of hybrid populations has yet to be explored experimentally in the lab. To fill this knowledge gap we created a pool of Saccharomyces cerevisiae and S. bayanus homoploid and aneuploid hybrids, and then investigated how selection in the form of incrementally increased temperature or ethanol impacted hybrid genome structure and adaptation. During 500 generations of continuous ammonia-limited, glucose-sufficient culture, temperature was raised from 25C to 46??C. This selection invariably resulted in nearly-complete loss of the S. bayanus genome, although the dynamics of genome loss differed among independent replicates. Temperature-evolved isolates were significantly more thermal tolerant and exhibited greater phenotypic plasticity than parental species and founding hybrids. By contrast, when the same hybrid pool was subjected to increases in exogenous ethanol from 0% to 14%, selection favored euploid S. cerevisiae x S. bayanus hybrids. Ethanol-evolved isolates exhibited significantly greater ethanol tolerance relative only to S. bayanus and one of the founding hybrids tested. Adaptation to thermal and ethanol stress manifested as heritable changes in cell wall structure demonstrated by resistance to zymolyase or micafungin treatment. This is the first study to show experimentally that the fate of interspecific hybrids critically depends on the type of selection they encounter during the course of evolution.
2012-08-01 | GSE24479 | GEO
Project description:RNA-binding proteins (RBPs) are critical regulators of gene expression and elucidating the interactions of RBPs with their RNA targets is necessary to understand how combinations of RBPs control transcriptome expression. The Quaking-related (QR) sub-family of STAR domain RBPs includes developmental regulators and tumor suppressors such as C. elegans GLD-1, which functions as a master regulator of germ line development. To understand how GLD-1 interacts with the transcriptome, we identified GLD-1 associated mRNAs by a ribonomic approach. The scale of GLD-1 mRNA interactions allowed us to determine rules governing GLD-1 target selection and to derive a predictive model where GLD-1 association with mRNA is based on the number and strength of 7-mer GLD-1 binding elements (GBEs) within UTRs. GLD-1/mRNA interactions were quantified, and predictions were verified both in vitro and in live animals, including by ‘transplantation’ experiments where ‘weak’ and ‘strong’ GBEs imposed translational repression of increasing strength on a non-target mRNA.Importantly, this study provides a unique quantitative picture of how an RBP interacts with its mRNA targets. As combinatorial regulation by multiple RBPs is thought to regulate gene expression, quantification of RBP/mRNA interactions should be a way to predict and potentially modify biological outcomes of complex posttranscriptional regulatory networks, and our analysis suggests that such an approach is possible.
2011-02-04 | GSE21591 | GEO