Project description:Sponge samples were analyzed on the QExactive in positive ESI mode without and with metal infusions (ca, vanadium, mg) and (fe, cu, zn).
Project description:Copper is a powerful antimicrobial and antiviral agent, which has interest through several biomedical applications. Nevertheless, how copper induces the cellular damage is not fully understood. Two main mechanisms are claimed to be involved, i.e. Cu catalyzed reactive oxygen species production (ROS) and replacements of other essential metal ions, such as Fe in Fe-S clusters by Cu. In the present work, we cumulate strong evidence for the importance of a third mechanism, which proposes that Cu damaging effects are due to its ability to cause massive protein aggregation in a ROS independent mechanism. We further show that Hsp33, a redox-regulated molecular chaperone in Escherichia coli, can prevent Cu-induced protein aggregation, suggesting an important role of the chaperoning system in defense against Cu-toxicity. A closer inspection of the mechanism of how Cu can activate Hsp33 revealed two intriguing features, i) a redox-state specificity of Cu+ vs Cu2+, and ii) an unprecedented mechanism of Hsp33-activation via a non-redox trans-metalation. Indeed, our data suggest that two Cu+ bind to the Zn-Cys4-finger site in Hsp33, which lead to a replacement of one Zn2+ by two Cu+ without Cys oxidation. In contrast, Cu2+ oxidizes the Cys in the Zn-finger, analogue to other oxidative stress effectors of Hsp33. Hence, the present results give several new insights in the antimicrobial mechanism of Cu and how bacteria defend against it.
Project description:Multidrug-resistant (MDR; resistance to >3 antimicrobial classes) Salmonella enterica serovar I 4,[5],12:i:- strains were linked to a 2015 foodborne outbreak from pork. Strain USDA15WA-1, associated with the outbreak, harbors an MDR module and the metal tolerance element Salmonella Genomic Island 4 (SGI-4). Characterization of SGI-4 revealed that conjugational transfer of SGI-4 resulted in the mobile genetic element (MGE) replicating as a plasmid or integrating into the chromosome. Tolerance to copper, arsenic, and antimony compounds was increased in Salmonella strains containing SGI-4 compared to strains lacking the MGE. Following Salmonella exposure to copper, RNA-seq transcriptional analysis demonstrated significant differential expression of diverse genes and pathways, including induction of numerous metal tolerance genes (copper, arsenic, silver, and mercury). Evaluation of swine administered elevated concentrations of zinc oxide (2,000 mg/kg) and copper sulfate (200 mg/kg) as an antimicrobial feed additive (Zn+Cu) in their diet for 4 weeks prior to and 3 weeks post-inoculation with serovar I 4,[5],12:i:- indicated that Salmonella shedding levels declined at a slower rate in pigs receiving in-feed Zn+Cu compared to control pigs (no Zn+Cu). The presence of metal tolerance genes in MDR Salmonella serovar I 4,[5],12:i:- may provide benefits for environmental survival or swine colonization in metal-containing settings.
Project description:Iron (Fe) and copper (Cu) are essential metal micronutrients that are necessary for many redox reactions. The uptake of these metals is tightly regulated in plants. Some redox processes can alternatively use Fe-containing proteins or Cu-containing proteins, depending on nutritional status. Copper deficiency can rescue a Cucumis melo Fe uptake deficient mutant, and Fe deficiency can result in increased accumulation of Cu. However, the system responsible for Fe-deficiency-regulated Cu-uptake is unknown. To understand the genes and gene networks associated with Fe-deficiency regulated Cu uptake and Fe-Cu cross-talk, we conducted transcriptomic profiling of roots and rosettes of spl7 (a Cu uptake deficient mutant in arabidopsis) and Col-0 (WT) grown under Fe, Cu and simultaneous Fe and Cu deficiency conditions.
Project description:Given that transition metals are essential cofactors in central biological processes, misallocation of the wrong metal ion to a metalloprotein can have resounding and often detrimental effects on diverse aspects of cellular physiology. Therefore, in an attempt to characterize unique and shared responses to chemically similar metals we have reconstructed physiological behaviors of Halobacterium NRC-1, an archaeal halophile, in sub-lethal levels of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II). Over 20% of all genes responded transiently within minutes of exposure to Fe(II), perhaps reflecting immediate large scale physiological adjustments to maintain homeostasis. At steady state, each transition metal induced growth arrest, attempts to minimize oxidative stress, toxic ion scavenging, increased protein turnover and DNA repair, and modulation of active ion transport. While several of these constitute generalized stress responses, up regulation of active efflux of Co(II), Ni(II), Cu(II), and Zn(II), down regulation of Mn(II) uptake and up regulation of Fe(II) chelation, confer resistance to the respective metals. We have synthesized all these discoveries into a unified systems level model to provide an integrated perspective of responses to six transition metals with emphasis on experimentally verified regulatory mechanisms. Finally, through comparisons across global transcriptional responses to different metals we provide insights into putative in vivo metal selectivity of metalloregulatory proteins and demonstrate that a systems approach can help rapidly unravel novel metabolic potential and regulatory programs of poorly studied organisms. Keywords: stress response, dose response 4 samples were analyzed. Each sample was dye-swapped (2 replicates per condition) and hybridized against a standard control.
Project description:Given that transition metals are essential cofactors in central biological processes, misallocation of the wrong metal ion to a metalloprotein can have resounding and often detrimental effects on diverse aspects of cellular physiology. Therefore, in an attempt to characterize unique and shared responses to chemically similar metals we have reconstructed physiological behaviors of Halobacterium NRC-1, an archaeal halophile, in sub-lethal levels of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II). Over 20% of all genes responded transiently within minutes of exposure to Fe(II), perhaps reflecting immediate large scale physiological adjustments to maintain homeostasis. At steady state, each transition metal induced growth arrest, attempts to minimize oxidative stress, toxic ion scavenging, increased protein turnover and DNA repair, and modulation of active ion transport. While several of these constitute generalized stress responses, up regulation of active efflux of Co(II), Ni(II), Cu(II), and Zn(II), down regulation of Mn(II) uptake and up regulation of Fe(II) chelation, confer resistance to the respective metals. We have synthesized all these discoveries into a unified systems level model to provide an integrated perspective of responses to six transition metals with emphasis on experimentally verified regulatory mechanisms. Finally, through comparisons across global transcriptional responses to different metals we provide insights into putative in vivo metal selectivity of metalloregulatory proteins and demonstrate that a systems approach can help rapidly unravel novel metabolic potential and regulatory programs of poorly studied organisms. Keywords: stress response, dose responseH 4 samples were analyzed. Each sample was dye-swapped (2 replicates per condition) and hybridized against a standard control
Project description:Given that transition metals are essential cofactors in central biological processes, misallocation of the wrong metal ion to a metalloprotein can have resounding and often detrimental effects on diverse aspects of cellular physiology. Therefore, in an attempt to characterize unique and shared responses to chemically similar metals we have reconstructed physiological behaviors of Halobacterium NRC-1, an archaeal halophile, in sub-lethal levels of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II). Over 20% of all genes responded transiently within minutes of exposure to Fe(II), perhaps reflecting immediate large scale physiological adjustments to maintain homeostasis. At steady state, each transition metal induced growth arrest, attempts to minimize oxidative stress, toxic ion scavenging, increased protein turnover and DNA repair, and modulation of active ion transport. While several of these constitute generalized stress responses, up regulation of active efflux of Co(II), Ni(II), Cu(II), and Zn(II), down regulation of Mn(II) uptake and up regulation of Fe(II) chelation, confer resistance to the respective metals. We have synthesized all these discoveries into a unified systems level model to provide an integrated perspective of responses to six transition metals with emphasis on experimentally verified regulatory mechanisms. Finally, through comparisons across global transcriptional responses to different metals we provide insights into putative in vivo metal selectivity of metalloregulatory proteins and demonstrate that a systems approach can help rapidly unravel novel metabolic potential and regulatory programs of poorly studied organisms. Keywords: time series
Project description:Cupriavidus metallidurans CH34 is a metal resistant beta-proteobacterium. The genome of this bacterium contain many genes involved in heavy metal resistance. Gene expression of C. metallidurans was studied after the addition of of Zn(II), Cd(II), Cu(II), Ni(II), Pb(II), Hg(II) or Co(II). Keywords: Heavy metal stress response Cultures of C. metallidurans CH34 were grown at 30°C until OD reached 0.6 (mid- exponential phase cultures). Heavy metals (0.8 mM of Zn(II), 0.5 mM of Cd(II), 0.1 mM of Cu(II), 0.6 mM of Ni(II), 0.4 mM of Pb(II), 5 uM of Hg(II) and 0.5 mM of Co(II)) were added to the culture for 30 minutes induction time. Total RNA was extracted, reverse-transcribed and labeled with Cy3-dCTP for the control (without metal) and with Cy5-dCTP for each conditions (challenged with one metal). Labeled cDNA were (control and one condition) added to a spotted slide for overnight hybridization at 42°C. Slides were scanned with a laser at 532 and 635 nm.
Project description:Given that transition metals are essential cofactors in central biological processes, misallocation of the wrong metal ion to a metalloprotein can have resounding and often detrimental effects on diverse aspects of cellular physiology. Therefore, in an attempt to characterize unique and shared responses to chemically similar metals we have reconstructed physiological behaviors of Halobacterium NRC-1, an archaeal halophile, in sub-lethal levels of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II). Over 20% of all genes responded transiently within minutes of exposure to Fe(II), perhaps reflecting immediate large scale physiological adjustments to maintain homeostasis. At steady state, each transition metal induced growth arrest, attempts to minimize oxidative stress, toxic ion scavenging, increased protein turnover and DNA repair, and modulation of active ion transport. While several of these constitute generalized stress responses, up regulation of active efflux of Co(II), Ni(II), Cu(II), and Zn(II), down regulation of Mn(II) uptake and up regulation of Fe(II) chelation, confer resistance to the respective metals. We have synthesized all these discoveries into a unified systems level model to provide an integrated perspective of responses to six transition metals with emphasis on experimentally verified regulatory mechanisms. Finally, through comparisons across global transcriptional responses to different metals we provide insights into putative in vivo metal selectivity of metalloregulatory proteins and demonstrate that a systems approach can help rapidly unravel novel metabolic potential and regulatory programs of poorly studied organisms. Keywords: stress response, dose response
Project description:Given that transition metals are essential cofactors in central biological processes, misallocation of the wrong metal ion to a metalloprotein can have resounding and often detrimental effects on diverse aspects of cellular physiology. Therefore, in an attempt to characterize unique and shared responses to chemically similar metals we have reconstructed physiological behaviors of Halobacterium NRC-1, an archaeal halophile, in sub-lethal levels of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II). Over 20% of all genes responded transiently within minutes of exposure to Fe(II), perhaps reflecting immediate large scale physiological adjustments to maintain homeostasis. At steady state, each transition metal induced growth arrest, attempts to minimize oxidative stress, toxic ion scavenging, increased protein turnover and DNA repair, and modulation of active ion transport. While several of these constitute generalized stress responses, up regulation of active efflux of Co(II), Ni(II), Cu(II), and Zn(II), down regulation of Mn(II) uptake and up regulation of Fe(II) chelation, confer resistance to the respective metals. We have synthesized all these discoveries into a unified systems level model to provide an integrated perspective of responses to six transition metals with emphasis on experimentally verified regulatory mechanisms. Finally, through comparisons across global transcriptional responses to different metals we provide insights into putative in vivo metal selectivity of metalloregulatory proteins and demonstrate that a systems approach can help rapidly unravel novel metabolic potential and regulatory programs of poorly studied organisms. Keywords: stress response, dose response