Project description:Resistance to oxidative stress plays a vital role in animal physiology, where it influences both life history traits and the ability to tolerate the effects of a myriad of environmental stressors. While stress resistance has previously been shown to share a role in shaping an organism's response to traits as varied as desiccation, thermal tolerance and xenobiotic resistance, heavy metal tolerance presents a particular challenge with regards to adaptation to stress. Heavy metals contamination can result in robust and persistent selection pressure: not only is acute exposure highly toxic, but metals can accumulate in the environment over long periods, prolonging this exposure. However, many heavy metals, such as copper and zinc, are also essential micronutrients, which may constrain adaption in high copper conditions. To determine the genetic basis of copper tolerance in European Drosophila melanogaster, we phenotyped 76 inbred lines sampled from nine locations across Western Europe on copper sulphate, demonstrating that that copper tolerance is a highly variable trait. A combination of long-read nanopore sequencing and high-throughput RNA-seq analysis carried out before and after copper exposure shows that while copper tolerance is a highly heterogenous trait, affected by changes in expression across multiple loci, the greatest changes in expression a seen in the digestive tract. In addition, a large proportion of genes found differentially expressed upon copper exposure have previously shown to be regulated by a number of transcription factors with known roles in a broad range of metabolic processes, indicating that while the initial response may be tissue restricted, long term affects of copper expose are more likely to be systemic.
Project description:Copper homeostasis is an important determinant for virulence of many human pathogenic fungi such as the highly prevalent yeast Candida albicans. However, beyond the copper transporter Ctr1, little is known regarding other genes or biological process that are affected by copper. To gain insight into the cellular processes that are modulated by copper abundance in C. albicans, we monitored the global gene expression dynamic under both copper depletion and excess using RNA-seq.
Project description:Copper (Cu) is not only one of the essential trace elements for animal body, but also an important nutrient component for normal physiology and metabolism of animal reproductive system. Lack or excess of copper will directly or indirectly affect animal reproductive activities. However, the effect of copper on reproductive performance of boars and sows has not been studied and the effect of excessive Copper addition on reproductive performance of sows is even less, and the molecular mechanism is poorly understood. Here, we document that copper has the negative effects on the oocyte maturation and Organelle function. We show that copper exposure perturbs the porcine oocyte meiotic maturation and impair the spindle/chromosome structure, displaying an obviously defective spindle assembly, and abnormal distribution of actin dynamics and cortical granules. In addition, single-cell transcriptome analysis identifies target effectors of copper in porcine oocytes, which was further demonstrated that copper exposure affects the distribution and function of mitochondria, and high ROS levels, DNA damage, and early apoptosis in porcine oocytes. Collectively, we demonstrate that copper exposure causes abnormalities in mitochondrial function and distribution, resulting in increased oxidative stress ROS levels, DNA damage and apoptosis, ultimately leading to decreased quality of porcine oocytes.
Project description:Chemical contamination is a common threat to biota thriving in estuarine and coastal ecosystems. In particular, trace metals tend to accumulate and exert deleterious effects on small invertebrates such as zooplankton, which are essential trophic links between phytoplankton and higher-level consumers in aquatic food webs. Beyond the direct effects of the contamination, we hypothesized that metal exposure could also affect the zooplankton microbiota, which in turn might further impair host fitness. To assess this assumption, copepods (Eurytemora affinis) were sampled in the oligo-mesohaline zone of the Seine estuary and exposed to dissolved copper (25 µg.L-1) over a 72-hour time period. Copepod response to copper treatment was assessed by determining transcriptomic changes in E. affinis along with shifts in its microbiota. Unexpectedly, very few genes were differentially expressed in copper-treated copepods compared to controls, with most of the reported differences involving genes upregulated in males compared to females. In contrast, copper increased the taxonomic diversity indices of the microbiota and resulted in substantial compositional changes at both the phyla and genus levels. Phylogenetic reconstruction of the microbiota further suggested that copper mitigated phylogenetic relatedness of taxa at the basal tree structure of the phylogeny, whereas it strengthened it at the terminal branches. Increased terminal phylogenetic clustering in copper-treated copepods concurred with higher proportions of bacterial genera previously identified as copper resistant (e.g., Pseudomonas, Acinetobacter, and Alkanindiges) and a higher relative abundance of the copA gene encoding a periplasmic inducible multi-copper oxidase. Overall, these results revealed very contrasting responses of E. affinis and its microbiota to copper exposure. The enrichment in micro-organisms likely to perform copper sequestration and/or enzymatic transformation processes, underlines here the need to follow the microbial component during the evaluation of the vulnerability of the zooplankton to the metallic stress.
Project description:To identify genes which are differentially expressed in Corynebacterium glutamicum in the absence of copper, we performed DNA microarray analyses of cells cultivated under copper starvation conditions compared to copper sufficiency.
Project description:Halobacterium salinarum is a halophillic archea that is capable of sustaining growth despite dramatic changes to the concentration of ions in its extracellular environment. Here we studied H. salinarum's specific adaptation response to the transition metal copper.
Project description:Erwinia amylovora causes fire blight. Copper is widely used for fire blight management but there is limited information on the pathogen’s copper homeostasis mechanisms. Upon identifyingE. amylovora strains with unusually high (EaR2, Ea17) and intermediate (Ea19) copper sensitivity, we characterized them phenotypically to find potential correlations with other traits.The highly copper-sensitive strains EaR2 and Ea17 grew slower, showed increased sensitivity to paraquat and cadmium, and developed a characteristic copper-dependent overproduction of amylovoran and levan, with patterns not observed in strain, Ea273, with regular copper tolerance. Copper sensitivity was also associated with higher copper-shock death rates after copper pre-exposure during growth. RNA-Seq analysis revealed similar responses to copper-shock in EaR2 and Ea273 but very different transcriptomic responses during copper adaptation(prolonged growth with copper). EaR2 responded to copper adaptation with earlier activation ofstress responses, exopolysaccharide biosynthesis pathways, and protein quality control systems, while reducing the expression of genes linked to iron uptake. Ea273 mostly displayed an activation of copper homeostasis-related genes, with a characteristic downregulation of histidine catabolism.
Project description:Copper-limiting growth conditions were thought to cause an induction of genes possibly involved in copper uptake and sorting. This rationale in mind, we performed microarray analyses on B. japonicum cells grown in three variations of the BVM minimal medium. Variant 1 contained 2 μM CuSO4 (copper excess). Variant 2 was prepared in HCl-treated glassware without any copper added (copper starvation). The residual copper concentration in this copper-starvation medium was analyzed by GF-AAS and determined to be 5 nM. Variant 3 (extreme copper limitation) was prepared like variant 2 but with the addition of 10 μM BCS and 1 mM ascorbic acid where BCS chelates Cu(I) selectively, and ascorbic acid reduces any Cu(II) to Cu(I). Changes in the transcription profiles were recorded by the pairwise comparison of cells grown in variant 2 vs. 1, and variant 3 vs. 2. Only a small set of genes were differentially up- or down-regulated when copper-starved cells were compared with cells grown in copper excess. Most notably, five genes located adjacent to each other on the B. japonicum genome displayed an increased expression: bll4882 to bll4878. The five genes were named pcuA, pcuB, pcuC, pcuD, and pcuE (mnemonic of proteins for Cu trafficking). The genes with decreased expression are either of unknown function or – not surprisingly – play a role in copper resistance. Extreme copper limitation (variant 3 vs. 2) did not further enhance the expression of the five pcu genes. Instead, another cluster of adjacent genes was strongly up-regulated: bll0889 to bll0883, which code for unidentified transport functions. Incidentally, the list also includes the copper chaperone ScoI. Taken together, copper-limiting growth conditions have led to the de-repression of genes potentially involved in copper acquisition.
Project description:The Oxford Nanopore (ONT) platform provides portable and rapid genome sequencing, and its ability to natively profile DNA methylation without complex sample processing is attractive for clinical sequencing. We recently demonstrated ONT shallow whole-genome sequencing to detect copy number alterations (CNA) from the circulating tumor DNA (ctDNA) of cancer patients. Here, we show that cell-type and cancer-specific methylation changes can also be detected, as well as cancer-associated fragmentation signatures. This feasibility study suggests that ONT shallow WGS could be a powerful tool for liquid biopsy, especially real-time medical applications.
Project description:The testing of NMs under the currently available standard toxicity tests does not cover many of the NMs specificities. One of the current recommended approaches forward lays on understanding the mechanisms of action as these can help predicting long term effects and safe-by-design production. Copper nanomaterials (Cu-NMs) usage has been highly increasing with the concern in terms of exposure, effect and associated risks. In the present study we used the high-throughput gene expression tool developed for Enchytraeus crypticus (44Kx4 Agilent microarray) to study to the effect of exposure to several copper forms. The copper treatments include two NMs (spherical and wires) and two copper-salt treatments (CuNO3 spiked and Cu field historical contamination). Testing was done based on reproduction effect concentrations (EC20, EC50) using 3 and 7 days exposure periods.