Academic literature on the topic 'Copper responsive regulator'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Copper responsive regulator.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Copper responsive regulator"
1
Peuser, Verena, Jens Glaeser, and Gabriele Klug. "The RSP_2889 gene product of Rhodobacter sphaeroides is a CueR homologue controlling copper-responsive genes." Microbiology 157, no. 12 (December 1, 2011): 3306–13. http://dx.doi.org/10.1099/mic.0.051607-0.
Full textAbstract:
Metal homeostasis is important in all living cells in order to provide sufficient amounts of metal ions for biological processes but to prevent toxic effects by excess amounts. Here we show that the gene product of RSP_2889 of the facultatively photosynthetic bacterium Rhodobacter sphaeroides is homologous to CueR, a regulator of copper metabolism in Escherichia coli and other bacteria. CueR binds to the promoter regions of genes for a copper-translocating ATPase and for a copper chaperone and is responsible for their high expression when cells are exposed to elevated levels of copper ions. While deletion of RSP_2889 has no significant effect on copper resistance, expression from a low-copy-number plasmid mediates increased sensitivity to copper.
2
Ettema, Thijs J. G., Arie B. Brinkman, Packo P. Lamers, Noor G. Kornet, Willem M. de Vos, and John van der Oost. "Molecular characterization of a conserved archaeal copper resistance (cop) gene cluster and its copper-responsive regulator in Sulfolobus solfataricus P2." Microbiology 152, no. 7 (July 1, 2006): 1969–79. http://dx.doi.org/10.1099/mic.0.28724-0.
Full textAbstract:
Using a comparative genomics approach, a copper resistance gene cluster has been identified in multiple archaeal genomes. The cop cluster is predicted to encode a metallochaperone (CopM), a P-type copper-exporting ATPase (CopA) and a novel, archaea-specific transcriptional regulator (CopT) which might control the expression of the cop genes. Sequence analysis revealed that CopT has an N-terminal DNA-binding helix–turn–helix domain and a C-terminal TRASH domain; TRASH is a novel domain which has recently been proposed to be uniquely involved in metal-binding in sensors, transporters and trafficking proteins in prokaryotes. The present study describes the molecular characterization of the cop gene cluster in the thermoacidophilic crenarchaeon Sulfolobus solfataricus. The polycistronic copMA transcript was found to accumulate in response to growth-inhibiting copper concentrations, whereas copT transcript abundance appeared to be constitutive. DNA-binding assays revealed that CopT binds to the copMA promoter at multiple sites, both upstream and downstream of the predicted TATA-BRE site. Copper was found to specifically modulate the affinity of DNA binding by CopT. This study describes a copper-responsive operon in archaea, a new family of archaeal DNA-binding proteins, and supports the idea that this domain plays a prominent role in the archaeal copper response. A model is proposed for copper-responsive transcriptional regulation of the copMA gene cluster.
3
Grosse-Siestrup, Benjamin T., Tuhina Gupta, Shelly Helms, Samantha L. Tucker, Martin I. Voskuil, Frederick D. Quinn, and Russell K. Karls. "A Role for Mycobacterium tuberculosis Sigma Factor C in Copper Nutritional Immunity." International Journal of Molecular Sciences 22, no. 4 (February 20, 2021): 2118. http://dx.doi.org/10.3390/ijms22042118.
Full textAbstract:
Sigma factor C (SigC) contributes to Mycobacterium tuberculosis virulence in various animal models, but the stress response coordinated by this transcription factor was undefined. The results presented here indicate that SigC prevents copper starvation. Whole genome expression studies demonstrate short-term (4-h) induction of sigC, controlled from a tetracycline-inducible promoter, upregulates ctpB and genes in the nonribosomal peptide synthase (nrp) operon. These genes are expressed at higher levels after 48-h sigC induction, but also elevated are genes encoding copper-responsive regulator RicR and RicR-regulated copper toxicity response operon genes rv0846–rv0850, suggesting prolonged sigC induction results in excessive copper uptake. No growth and global transcriptional differences are observed between a sigC null mutant relative to its parent strain in 7H9 medium. In a copper-deficient medium, however, growth of the sigC deletion strain lags the parent, and 40 genes (including those in the nrp operon) are differentially expressed. Copper supplementation reverses the growth defect and silences most transcriptional differences. Together, these data support SigC as a transcriptional regulator of copper acquisition when the metal is scarce. Attenuation of sigC mutants in severe combined immunodeficient mice is consistent with an inability to overcome innate host defenses that sequester copper ions to deprive invading microbes of this essential micronutrient.
4
Young, Christie A., Lily D. Gordon, Zhong Fang, Robert C. Holder, and Sean D. Reid. "Copper Tolerance and Characterization of a Copper-Responsive Operon,copYAZ, in an M1T1 Clinical Strain of Streptococcus pyogenes." Journal of Bacteriology 197, no. 15 (May 26, 2015): 2580–92. http://dx.doi.org/10.1128/jb.00127-15.
Full textAbstract:
ABSTRACTInfection withStreptococcus pyogenesis associated with a breadth of clinical manifestations ranging from mild pharyngitis to severe necrotizing fasciitis. Elevated levels of intracellular copper are highly toxic to this bacterium, and thus, the microbe must tightly regulate the level of this metal ion by one or more mechanisms, which have, to date, not been clearly defined. In this study, we have identified two virulence mechanisms by whichS. pyogenesprotects itself against copper toxicity. We defined a set of putative genes,copY(for a regulator),copA(for a P1-type ATPase), andcopZ(for a copper chaperone), whose expression is regulated by copper. Our results indicate that these genes are highly conserved among a range of clinicalS. pyogenesisolates. ThecopY,copA, andcopZgenes are induced by copper and are transcribed as a single unit. Heterologous expression assays revealed thatS. pyogenesCopA can confer copper tolerance in a copper-sensitiveEscherichia colimutant by preventing the accumulation of toxic levels of copper, a finding that is consistent with a role for CopA in copper export. Evaluation of the effect of copper stress onS. pyogenesin a planktonic or biofilm state revealed that biofilms may aid in protection during initial exposure to copper. However, copper stress appears to prevent the shift from the planktonic to the biofilm state. Therefore, our results indicate thatS. pyogenesmay use several virulence mechanisms, including altered gene expression and a transition to and from planktonic and biofilm states, to promote survival during copper stress.IMPORTANCEBacterial pathogens encounter multiple stressors at the host-pathogen interface. This study evaluates a virulence mechanism(s) utilized byS. pyogenesto combat copper at sites of infection. A better understanding of pathogen tolerance to stressors such as copper is necessary to determine how host-pathogen interactions impact bacterial survival during infections. These insights may lead to the identification of novel therapeutic targets that can be used to address antibiotic resistance.
5
Quinn, Jeanette M., Janette Kropat, and Sabeeha Merchant. "Copper Response Element and Crr1-Dependent Ni2+-Responsive Promoter for Induced, Reversible Gene Expression in Chlamydomonas reinhardtii." Eukaryotic Cell 2, no. 5 (October 2003): 995–1002. http://dx.doi.org/10.1128/ec.2.5.995-1002.2003.
Full textAbstract:
ABSTRACT The Cpx1 and Cyc6 genes of Chlamydomonas reinhardtii are activated in copper-deficient cells via a signal transduction pathway that requires copper response elements (CuREs) and a copper response regulator defined by the CRR1 locus. The two genes can also be activated by provision of nickel or cobalt ions in the medium. The response to nickel ions requires at least one CuRE and also CRR1 function, suggesting that nickel interferes with a component in the nutritional copper signal transduction pathway. Nickel does not act by preventing copper uptake/utilization because (i) holoplastocyanin formation is unaffected in Ni2+-treated cells and (ii) provision of excess copper cannot reverse the Ni-dependent activation of the target genes. The CuRE is sufficient for conferring Ni-responsive expression to a reporter gene, which suggests that the system has practical application as a vehicle for inducible gene expression. The inducer can be removed either by replacing the medium or by chelating the inducer with excess EDTA, either of which treatments reverses the activation of the target genes.
6
Olaya-Abril, Alfonso, Víctor M. Luque-Almagro, Jesús Hidalgo-Carrillo, Eduardo Chicano-Gálvez, Francisco J. Urbano, Conrado Moreno-Vivián, David J. Richardson, and María Dolores Roldán. "The NtrYX Two-Component System of Paracoccus denitrificans Is Required for the Maintenance of Cellular Iron Homeostasis and for a Complete Denitrification under Iron-Limited Conditions." International Journal of Molecular Sciences 23, no. 16 (August 15, 2022): 9172. http://dx.doi.org/10.3390/ijms23169172.
Full textAbstract:
Denitrification consists of the sequential reduction of nitrate to nitrite, nitric oxide, nitrous oxide, and dinitrogen. Nitrous oxide escapes to the atmosphere, depending on copper availability and other environmental factors. Iron is also a key element because many proteins involved in denitrification contain iron-sulfur or heme centers. The NtrYX two-component regulatory system mediates the responses in a variety of metabolic processes, including denitrification. A quantitative proteomic analysis of a Paracoccus denitrificans NtrY mutant grown under denitrifying conditions revealed the induction of different TonB-dependent siderophore transporters and proteins related to iron homeostasis. This mutant showed lower intracellular iron content than the wild-type strain, and a reduced growth under denitrifying conditions in iron-limited media. Under iron-rich conditions, it releases higher concentrations of siderophores and displayes lower nitrous oxide reductase (NosZ) activity than the wild-type, thus leading to nitrous oxide emission. Bioinformatic and qRT-PCR analyses revealed that NtrYX is a global transcriptional regulatory system that responds to iron starvation and, in turn, controls expression of the iron-responsive regulators fur, rirA, and iscR, the denitrification regulators fnrP and narR, the nitric oxide-responsive regulator nnrS, and a wide set of genes, including the cd1-nitrite reductase NirS, nitrate/nitrite transporters and energy electron transport proteins.
7
Upadhyay, Srijana, Guadalupe Torres, and Xiaorong Lin. "Laccases Involved in 1,8-Dihydroxynaphthalene Melanin Biosynthesis in Aspergillus fumigatus Are Regulated by Developmental Factors and Copper Homeostasis." Eukaryotic Cell 12, no. 12 (October 11, 2013): 1641–52. http://dx.doi.org/10.1128/ec.00217-13.
Full textAbstract:
ABSTRACTAspergillus fumigatusproduces heavily melanized infectious conidia. The conidial melanin is associated with fungal virulence and resistance to various environmental stresses. This 1,8-dihydroxynaphthalene (DHN) melanin is synthesized by enzymes encoded in a gene cluster inA. fumigatus, including two laccases, Abr1 and Abr2. Although this gene cluster is not conserved in all aspergilli, laccases are critical for melanization in all species examined. Here we show that the expression ofA. fumigatuslaccases Abr1/2 is upregulated upon hyphal competency and drastically increased during conidiation. The Abr1 protein is localized at the surface of stalks and conidiophores, but not in young hyphae, consistent with the gene expression pattern and its predicted role. The induction of Abr1/2 upon hyphal competency is controlled by BrlA, the master regulator of conidiophore development, and is responsive to the copper level in the medium. We identified a developmentally regulated putative copper transporter, CtpA, and found that CtpA is critical for conidial melanization under copper-limiting conditions. Accordingly, disruption of CtpA enhanced the induction ofabr1andabr2, a response similar to that induced by copper starvation. Furthermore, nonpigmentedctpAΔ conidia elicited much stronger immune responses from the infected invertebrate hostGalleria mellonellathan the pigmentedctpAΔ or wild-type conidia. Such enhancement in elicitingGalleriaimmune responses was independent of thectpAΔ conidial viability, as previously observed for the DHN melanin mutants. Taken together, our findings indicate that both copper homeostasis and developmental regulators control melanin biosynthesis, which affects conidial surface properties that shape the interaction between this pathogen and its host.
8
Raghunandanan, Sajith, Ranjit Ramachandran, Roshna Lawrence Gomez, Sivasankar Devanarayanan, Akhila Bommakanti, Anand Kumar Kondapi, Raghavan Varadarajan, and Ramakrishnan Ajay Kumar. "Rv0474 is a copper‐responsive transcriptional regulator that negatively regulates expression of RNA polymerase β subunit in Mycobacterium tuberculosis." FEBS Journal 285, no. 20 (September 5, 2018): 3849–69. http://dx.doi.org/10.1111/febs.14637.
Full text
9
van Vliet, Arnoud H. M., Ernst J. Kuipers, Barbara Waidner, Beverly J. Davies, Nicolette de Vries, Charles W. Penn, Christina M. J. E. Vandenbroucke-Grauls, Manfred Kist, Stefan Bereswill, and Johannes G. Kusters. "Nickel-Responsive Induction of Urease Expression inHelicobacter pylori Is Mediated at the Transcriptional Level." Infection and Immunity 69, no. 8 (August 1, 2001): 4891–97. http://dx.doi.org/10.1128/iai.69.8.4891-4897.2001.
Full textAbstract:
ABSTRACT The nickel-containing enzyme urease is an essential colonization factor of the gastric pathogen Helicobacter pylori, as it allows the bacterium to survive the acidic conditions in the gastric mucosa. Although urease can represents up to 10% of the total protein content of H. pylori, expression of urease genes is thought to be constitutive. Here it is demonstrated that H. pyloriregulates the expression and activity of its urease enzyme as a function of the availability of the cofactor nickel. Supplementation of brucella growth medium with 1 or 100 μM NiCl2 resulted in up to 3.5-fold-increased expression of the urease subunit proteins UreA and UreB and up to 12-fold-increased urease enzyme activity. The induction was specific for nickel, since the addition of cadmium, cobalt, copper, iron, manganese, or zinc did not affect the expression of urease. Both Northern hybridization studies and a transcriptionalureA::lacZ fusion demonstrated that the observed nickel-responsive regulation of urease is mediated at the transcriptional level. Mutation of the HP1027 gene, encoding the ferric uptake regulator (Fur), did not affect the expression of urease in unsupplemented medium but reduced the nickel induction of urease expression to only twofold. This indicates that Fur is involved in the modulation of urease expression in response to nickel. These data demonstrate nickel-responsive regulation of H. pyloriurease, a phenomenon likely to be of importance during the colonization and persistence of H. pylori in the gastric mucosa.
10
Karmacharya, Jayram, Prasansah Shrestha, So-Ra Han, Hyun Park, and Tae-Jin Oh. "Complete Genome Sequencing of Polar Arthrobacter sp. PAMC25284, Copper Tolerance Potential Unraveled with Genomic Analysis." International Journal of Microbiology 2022 (August 25, 2022): 1–12. http://dx.doi.org/10.1155/2022/1162938.
Full textAbstract:
The genus Arthrobacter is a known group of Gram-positive, opportunistic pathogenic bacteria from cold climates, with members that are believed to play a variety of roles at low temperatures. However, their survival mechanisms in frigid environments like the Antarctic are still unknown. We identified a species of Arthrobacter isolated from seawater in the polar region using 16S rRNA sequence analysis. The strain PAMC25284 genome consists of a circular chromosome with a GC content of 65.6% and is projected to contain 3,588 genes, of which 3,150 are protein coding, 366 are pseudogenes, 19 are rRNA coding, and 50 are tRNA coding genes. Using comparative genomics, we showed that PMAC25284 has copper-transporting ATPases, copper chaperone, copper-responsive transcriptional regulator, and multi-copper oxidase domains, which are found in both Gram-positive (like Mycobacterium tuberculosis and Enterococcus hirae) and Gram-negative bacteria (like E. coli and Pseudomonas aeruginosa). The existence of 4 multi-copper oxidase genes, which supplied an additional copper defense mechanism, could be intriguing information regarding Gram-positive bacteria such as Arthrobacter sp. PAMC25284. In addition, our strain PAMC25284 has the same MmcO gene as M. tuberculosis, with a locus tag KY499_RS04055 similarity of 40.61%, which is the highest among the Gram-positive and Gram-negative bacteria studied for this gene. Our cold-adapted Arthrobacter sp. strain PAMC25564 was published previously but did not contain a multi-copper oxidase domain-containing gene, but strain PAMC25284 was studied in this study.
Dissertations / Theses on the topic "Copper responsive regulator"
1
Woodacre, Alexandra. "Copper-responsive transcriptional regulation in Candida albicans." Thesis, University of Leicester, 2007. http://hdl.handle.net/2381/30380.
Full textAbstract:
The copper-containing protein superoxide dismutase is required for the virulence of C. albicans in a mouse model. Previous work in our laboratory has shown that copper uptake and regulation in C. albicans has some similarities to Saccharomyces cerevisiae, including the activation of the copper transporter gene CaCTR1 in low copper conditions by the transcription factor CaMac1p. However, further analysis in this study has demonstrated that the actual mechanism of regulation by CaMac1p is different from that of S. cerevisiae Mac1p.;This thesis demonstrates for the first time that the CaMAC1 gene is transcriptionally autoregulated in a copper-dependent manner. This is in contrast to the S. cerevisiae MAC1 homologue, which is constitutively transcribed. The presence of one binding site for CaMac1p in the promoters of CaCTR1, CaMAC1 and the ferric/cupric reductase gene CaFRE7 is sufficient for copper-responsive regulation. In contrast, two promoter elements are essential for normal levels of copper-dependent activation by S. cerevisiae Mac1p. CaMac1p is also involved in the regulation of the iron-responsive transcriptional repressor gene SFU1 and the alternative oxidase gene AOX2. This work describes key features of the copper uptake system in the human pathogen C. albicans that distinguishes it from similar processes in the model yeast S. cerevisiae. Transcriptional autoregulation of the CaMAC1 gene could enable C. albicans to respond more precisely to environmental changes, conferring an adaptation to the human host that may be an advantage in the disease process.
2
Pinto, Cecilia de Agrela. "The two-component system of a novel copper resistant operon of Marinobacter hydrocarbonoclasticus." Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/10062.
Full textAbstract:
Dissertation for the Master’s Degree in Structural and Functional BiochemistryThe majority of bacterial heavy metal resistance systems are regulated by twocomponent signal transduction systems. Stimuli from the environment interact with the histidine kinase, which in turn activates the response regulator by phosphorylation. The effector domain of the response regulator then binds to DNA, eliciting the specific response. Analysis of the Marinobacter hydrocarbonoclasticus genome revealed the presence of genes, copXAB, that code for proteins associated with copper response. The biochemical characterization of the two-component signal transduction system, copSR, is of interest due to the vital role it plays in the regulation of expression of the copXAB operon. The genes that encode for the CopR and CopS_C (cytosolic sensor domain of CopS) proteins were heterologously expressed in E.coli and expression was optimized for the production of soluble protein using LB medium. Due to solubility problems, the genes that code for these proteins were cloned as hexahistidine or glutathione S-transferase fusion proteins. CopR and its domains were optimally expressed at 16°C for 16 and 3 h after induction, respectively, whilst CopS_C was expressed at 37°C during 3 h after induction. Proteins were purified using different chromatographic strategies, most of them using affinity chromatography. The yields of pure protein per liter of growth culture obtained after complete purification from the soluble cellular extract were: 0.14 to 0.23 mg/L for CopR; 0.42 mg/L, CopR_NHis6; for the CopR_CHis6 it was 0.16 mg/L and 4.2 mg/L of CopS_C. The molecular mass of each protein was determined by gel filtration, 31 kDa for CopR, 17.5 kDa for CopR_NHis6, 15.1 kDa for CopR_CHis6 and 38.2 kDa for CopS_C. In the case of CopS_C there is the possibility that a dimer is formed, which should be evaluated. From the evaluation of disulfide bonds, using SDS PAGE and PAGE gels, all proteins or protein domains appeared to be monomers when in the presence of β-MEtOH. Circular dichroism evaluated the state of folding of the CopS_C and CopR proteins, which were shown to be folded in which the α-helix structures predominate. A model structure for CopR was also determined which agrees with this analysis. However, in the case of the CopR domains, the data obtained merely indicate folding, due to the low concentrations of the proteins. Phosphorylation and electrophoresis mobility shift assays of the CopR protein were, for the most part, inconclusive. However, in the absence of BSA, formation of the CopR:DNA complex in a gel filtration column is observed, though requires additional evaluation.
3
Singh, Prashant. "Regulation of the Menkes Protein in neuroendocrine Cells in Response to Copper." Bowling Green State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1237841061.
Full text
4
Bell, Francesca Y. "Copper tolerance of Listeria monocytogenes strain DRDC8." Thesis, 2010. http://hdl.handle.net/2440/65482.
Full textAbstract:
Listeria monocytogenes is one of the most important food-borne pathogens due to the severity of the disease it can cause. While the virulence factors required for effective colonisation and infection of mammalian hosts have been well described, other genes may modulate disease persistence. For L. monocytogenes strain DRDC8, the ctpA gene encodes a copper transporting P-type ATPase that apparently maintains intra-cellular copper ion
homeostasis (Francis & Thomas, 1997a) and is also required for persistent infection of the liver and spleens of mice (Francis & Thomas, 1997b). However, the distribution of this gene is apparently limited to non-clinically derived environmental L. monocytogenes isolates (Bell, 2002). This may be explained by carriage of ctpA on plasmid DNA (Bell, 2002). Based on predictions of function and proximity to the ctpA gene (pCT0020), ORFs pCT0017, pCT0018, pCT0019 and ctpA were identified as a putative a cop-like operon involved in copper ion transport in L. monocytogenes (Bell, 2002). Southern hybridisation analysis was used to confirm that the ctpA gene is carried on plasmid pCT100 in strain DRDC8. In addition, evidence to suggest that ctpA was encoded by bacteriophage DNA was not obtained. Furthermore, sequence analysis of DNA flanking ctpA identified ORFs that encode polypeptide sequences similar to proteins involved in plasmid replication and other plasmid-associated functions. Mating experiments provided evidence to show that plasmid pCT100 is not conjugative. This suggested that lateral transfer of this plasmid between cohabitating organisms may be limited. Sequence analysis of a 37.279 kbp region of plasmid pCT100 from L. monocytogenes strain DRDC8 (GenBank Accession U15554) showed this plasmid had regions of gene content and organisation similar to that of other characterised Listeria plasmids, particularly plasmid pLI100 from L. innocua CLIP11262 and plasmid pLM80 from L. monocytogenes strain 4b H7858. Gene’s common to these plasmids included those implicated in plasmid DNA replication, DNA transposition/insertion and heavy metal (cadmium) transport. Sequence analysis of plasmid pCT100 also identified regions of DNA absent from other Listeria sequences. For example, a DNA region encoding a series of polypeptide sequences similar to chromosomally-encoded proteins involved in copper transport in other Gram-positive bacteria was identified. The ORFs encoded by this region (pCT0017, pCT0018, pCT0019 and pCT0020 (ctpA), pCT0023, pCT0024, pCT0025, pCT0026, pCT0027) represent a novel cluster of genes implicated in copper homeostasis/tolerance that had not been previously described for other Listeria spp. PCR analysis was used to show that carriage of this copper gene cluster may be restricted to only some Australian ctpA positive L. monocytogenes isolates, typically of dairy and poultry origin. In addition to these plasmid-encoded ORFs, PCR and sequence analysis identified a chromosomal ORF (cutR) also implicated in copper homeostasis/tolerance for strain DRDC8. cutR encodes a polypeptide similar to chromosomally-encoded coppertranslocating P-type ATPases from other Listeria species. The role of ORFs cutR, pCT0017, pCT0018 and pCT0019 in copper tolerance was assessed by comparison of the ability of wild type parent strain DRDC8 and variants containing independent mutations (pCT0017::erm, pCT0018::erm, pCT0019::erm or cutR::erm) to tolerate copper ion stress. The impact of loss of these genes (as a result of curing strain DRDC8 and cutR::erm derivatives of plasmid pCT100) on copper tolerance by DRDC8 was also examined. Minimal inhibitory concentration (MIC) and growth experiments showed that inactivation of cutR, pCT0018 or pCT0019, or removal of plasmid-encoded genes by curing DRDC8 of plasmid DNA, had a significant effect on copper tolerance. In addition, loss of plasmid DNA combined with disruption of cutR was shown to render cells completely incapable of growth in high levels of copper (14 mM CuSO4). This data indicated that pCT0018, pCT0019 and cutR are involved in copper tolerance of L. monocytogenes strain DRDC8. MIC experiments also provided evidence to show that ORFs cutR and pCT0018 may play an additional role in tolerance to cadmium. Interestingly, a L. monocytogenes mutant carrying an erm insertion within pCT0017 could not be constructed. However, evidence that showed that ORF pCT0017 encodes a CopY-like negative repressor protein directly implicated this ORF in copper tolerance. DNA gel shift experiments were used to show that pCT0017 protein binds to
two ‘cop box-like’ nucleotide sequences located upstream of the pCT0017 translation start site. Binding occurs in a copper-dependant manner that is consistent with published models of CopY-like protein function. Thus pCT0017 protein may regulate expression of ORFs pCT0017, pCT0018, pCT0019 and ctpA in a copper responsive manner. This is consistent with the view that these ORFs form a cop-like operon involved in copper homeostasis. In conclusion, L. monocytogenes strain DRDC8 displayed an exceptional tolerance to high concentrations of copper ions. The data obtained suggested that both chromosomal and plasmid-encoded genes are involved in copper homeostasis/tolerance of DRDC8. This particular strain may have acquired multiple genes involved in copper tolerance from a cohabitating Gram-positive bacterium in response to exposure to high levels of copper within the environment. Given that strain DRDC8 is an Australian dairy isolate, these genes may provide a selective advantage for survival of other L. monocytogenes strains in associated environments.Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2010
Books on the topic "Copper responsive regulator"
1
Dorbeck-Jung, Bärbel. Transcending the Myth of Law’s Stifling Technological Innovation. Edited by Roger Brownsword, Eloise Scotford, and Karen Yeung. Oxford University Press, 2016. http://dx.doi.org/10.1093/oxfordhb/9780199680832.013.59.
Full textAbstract:
This chapter explores the lessons that can be drawn from how adaptive drug licensing processes cope with legitimacy issues of regulatory connections. The exploration assumes that a responsive approach to technology regulation offers opportunities to meet legitimacy requirements. Looking at existing and proposed adaptive drug licensing pathways through the lens of this theoretical frame we see a realistic responsive approach to regulation. By indicating that adaptive licensing can bring beneficial medicinal drugs earlier to patients this approach seems to be equipped to transcend the myth of law’s stifling technological innovation. The evaluation of the current stage of adaptive drug licensing leads to three tentative lessons. First, a shared interest, accompanied by strong drivers and enablers, is crucial; second, ongoing prudent coordination of a leading regulatory agency is essential; third, to ensure that new responsibilities and the norms of participation, transparency, integrity, and accountability are taken seriously a new social contract can be supportive.
Book chapters on the topic "Copper responsive regulator"
1
Merchant, Sabeeha. "Reciprocal, Copper-Responsive Accumulation of Plastocyanin and Cytochrome c 6 in Algae and Cyanobacteria: A Model for Metalloregulation of Metalloprotein Synthesis." In Metal Ions in Gene Regulation, 450–67. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4615-5993-1_17.
Full text
2
Prova, Ananya, and Md Saeed Sultan. "Techniques against Distinct Abiotic Stress of Rice." In Advances in Plant Defense Mechanisms [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.105808.
Full textAbstract:
Plants cannot physically escape environmental stresses because they are sessile organisms, which can stunt their growth. As a result, plants have had to evolve distinct strategies to deal with abiotic stress. Indeed, responding to and eventually adapting to abiotic stress may be a driving force in speciation. Because of the complexity of stress, multiple sensors, rather than a single sensor, are more likely to be responsible for stress perception. Stress-induced gene issues can be divided into two categories: those involved in stress tolerance and those involved in signal transduction. Stress-tolerance genes help plants cope with stress in both short- and long-term responses. These can include the synthesis of chaperones and enzymes for osmolyte biosynthesis. And, as with cold stress, detoxification causes a change in the composition of membrane lipids. Gene products can also function as transcription regulators, controlling groups of stress-related genes, or as components in the production of regulatory molecules. It has been shown that multiple signaling pathways can be activated during stress, resulting in similar responses to different triggers.
3
Akhter, Shameem, Nayem Rahman, Mahmud Ullah, and Mohammad Nirjhar Rahman. "Shaping Competitive Strategies for the Computer Industry." In Advances in Human and Social Aspects of Technology, 189–207. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-6367-9.ch010.
Full textAbstract:
Accelerated response to competition with appropriate actions is one of the major determinants for a firm's sustenance and survival. Both operational and financial performances in terms of gaining and/or keeping competitive advantage always remain under the watchful eyes of the relevant stakeholders in an industry. A firm has to be very vigilant to cope with the internal and external changes it faces over the different phases of its growth. Just like any other industry, this is equally true, in fact more true for the computer industry as well. Continuous innovation in the computer industry has made it a very fast growing and fiercely competitive industry in the field of modern technologies. Firms in this industry always have to be on their toes to tackle the fierce competition created due to many obvious reasons. This study examines the computer industry in the light of Michael Porter's framework for analyzing the profitability. Threats of new entrants and substitute products, bargaining power of both suppliers and buyers, and regular rivalry among the competitors have been analyzed critically. This study may have significant implications in evaluating the competitive strategies developed and applied by the incumbent firms in and the new entrants into the computer manufacturing industry.
Conference papers on the topic "Copper responsive regulator"
1
He, Ge, Yangqing Dou, Xiang Guo, and Yucheng Liu. "Effects of Grain Size on Ballistic Response of Copper Materials." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70585.
Full textAbstract:
Numerical simulations were conducted to compare ballistic performance and penetration mechanism of copper (Cu) with four representative grain sizes. Ballistic limit velocities for coarse-grained (CG) copper (grain size ≈ 90 μm), regular copper (grain size ≈ 30 μm), fine-grained (FG) copper (grain size ≈ 890 nm), and ultrafine-grained (UG) copper (grain size ≈ 200 nm) were determined for the first time through the simulations. It was found that the copper with reduced grain size would offer higher strength and better ductility, and therefore renders improved ballistic performance then the CG and regular copper. High speed impact and penetration behavior of the FG and UG copper was also compared with the CG coppers strengthened by nanotwinned (NT) regions. The comparison results showed the impact and penetration resistance of UG copper is comparable to the CG copper strengthened by NT regions with the minimum twin spacing. Therefore, besides the NT regions-strengthened copper, the single phase copper with nanoscale grain size could also be a strong candidate material for better ballistic protection. A computational modeling and simulation framework was proposed for this study, in which Johnson-Cook (JC) constitutive material model is used to predict the plastic deformation of Cu and Ni; JC damage model is to capture the penetration and fragmentation behavior of Cu; Bao-Wierzbicki (B-W) failure criterion defines the material’s failure mechanisms; and temperature increase during this adiabatic penetration process is given by the Taylor-Quinney method.
2
Biddle, Nathan, Jorge Siqueira, Anne Guedes, Mariana França, Nayara Ferreira, and Daniela Coelho. "How Brazil Operators and Regulators Implemented, Audited and Learned from COVID-19." In Offshore Technology Conference. OTC, 2021. http://dx.doi.org/10.4043/31255-ms.
Full textAbstract:
Abstract The COVID-19 pandemic brought with it the potential risk for personnel abandonment of various oil and gas installations that was unprecedented in the industry. Uncertainties on how to implement and monitor these processes was a significant challenge. This pandemic scenario required that operators and regulators work together to reformulate their normal way of working to decrease the risk of virus exposure to personnel, while still ensuring critical elements were implemented for safe operations. Regulators were required to act quickly to implement and adjust regulations to meet the new demands for safe operations during the global pandemic. Through joint discussions with industry associations and an understanding of the situation, the Brazilian oil and gas industry regulator, ANP, was able to immediately implement tracking requirements and, within less than one month after formal declaration of a state of emergency, issued new regulations for the restart and operations of installations. These measures assisted in a better understanding of the COVID-19 situation onboard offshore installations and in disseminating learnings across Exploration and Production (E&P) industry. Operators across Brazil all implemented modified emergency response plans, new hazard identification measures and means to reduce the risks of these identified hazards in response to COVID-19. The ANP worked to oversee the manner in which these measures were conducted, while successfully assisting in reducing demands on offshore work during the pandemic by migrating to a fully-remote means of regulatory enforcement and auditing. Regulators and operators all worked across five key areas and within the joint efforts significantly mitigated the impacts which COVID-19 had on the industry in Brazil. These key areas were: Operational Safety Documentation, procedures within the regulations and management system to cope with the pandemic scenario; Tracking of COVID-19 cases and effective response measures/learnings across industry; Hazard Identification related to the operational conditions impacted by the COVID-19 crisis; Risk Assessment for the identified hazards because of the pandemic; and Emergency Response plans for response to the worst-case operational scenario during a pandemic. Although severe outbreaks did occur on several installations, causing temporary shutdowns, there have to date been no major operational accidents as a result of COVID-19 personnel evacuations or procedures. Additionally, the total oil and gas production levels for Brazil have been maintained or increased across the sector. These high-level performance indicators demonstrate that through the efforts of the ANP, operators, service providers and other regulators, the pandemic situation is being managed successfully while the industry also continues meet the necessary energy demands of the country. Although the global pandemic has been a sobering and dark period in history for all, there have been positive outcomes for the oil and gas exploration and production industry. The three most apparent positive outcomes are: Ability of regulators and operators to adapt together; A focus by all players on the safety of the workforce and environment;. Effectively operating under adverse conditions with reduced and essential workforce.
3
Matos, Vini´cius, Joel Sena Sales, and S. H. Sphaier. "Seakeeping Tests With Gaussian Wave Packets." In ASME 2005 24th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2005. http://dx.doi.org/10.1115/omae2005-67259.
Full textAbstract:
An important property used in the design stage of floating systems is the RAO (Response Amplitude Operator), the transfer function, for motions, forces and so on. This importance has motivated the development of several analytical, numerical and experimental tools to obtain the hydrodynamic behavior of platforms and ships. Experimental model tests in wave tanks are advisable for the accurate evaluation of the body movements. Three known techniques are used to obtain the RAO curves: tests with regular, irregular and transient waves. In the present work, special attention is given to the technique used to perform model testing with one type of transient wave: the Gaussian Wave Packet. The advantages of using such technique are discussed and results are also presented for a semi-submersible model during tests carried out at Laborato´rio de Tecnologia Oceaˆnica - LabOceano/COPPE/UFRJ, Brazil. Numerical calculations and tests with regular and irregular waves are used for validation and comparison.
4
Vodenicharov, Asen. "THE MANAGEMENT ORGAN IN THE ARCHITECTURE OF THE EUROPEAN STRUCTURES FOR BUSINESS ASSOCIATION." In 4th International Scientific Conference – EMAN 2020 – Economics and Management: How to Cope With Disrupted Times. Association of Economists and Managers of the Balkans, Belgrade, Serbia, 2020. http://dx.doi.org/10.31410/eman.2020.129.
Full textAbstract:
Council Regulation (EC) No 2157/2001 of 8 October 2001 on the Statute for a European company (SE) and Council Regulation (EC) No 1435/2003 of 22 July 2003 on the Statute for a European Cooperative Society (SCE), as well as other community acts, govern the legal status of the management organ with two-tier architecture of European structures for business association. In this paper, it is concluded that the management organ shall be responsible for managing the appropriate organizational and legal entities. Therefore, it can carry out day-to-day management of the organization according to the decisions of the general assembly and the supervisory authority. It is stated that assigning day-to-day operational management to the CEOs, members of the management organ, can be defined as transferring certain aspects of their power, while keeping their right of making final decisions. The collective character of the considered authority, carrying out its duties on the principle of collegiality, raises a line of questions, which are considered in this paper. Subjects of study are also the horizontal and vertical relationships of the management organ, considering the representative power, as well as the different types of responsibilities. The discussed problems are in a relatively legal aspect of the legal regulations of the Member States.
5
Loucks, Richard B. "The Effect of Transducer Response Rate on Thermal Radiation Data." In ASME 1993 International Computers in Engineering Conference and Exposition. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/cie1993-0040.
Full textAbstract:
Abstract The Thermal Radiation Source (TRS) at ARL is used as a research tool to develop a reliable TRS unit for integration with the 2.44 m probative tube. Part of this study includes measuring the rise and fall times as well as the extent of flux variation of the TRS events. The Garden type gage is the primary transducer used to measure the flux output. This gage consists of a constantan diaphragm welded to a copper wire and body. This creates two thermocouple junctions. The electrical output of the gage is linearly related to the incident thermal radiation on the face of the diaphragm. A concern is about the response rate of these gages. The typical gage used in TRS work has a response rate of one time constant within 50 ms. In the past, the transient output of the TRS was considered slow. A faster acting gage was not necessary. To test this theory, a mathematical correction formula was applied to existing TRS data. The correction formulation was to demonstrate the actual incident radiation on the gage face by assuming a response rate. The data was processed using the correction formula. The results of the correction processing yielded a higher rise and fall time, as expected, but demonstrated a much higher flux variation during a TRS event. The overall fluence remained the same. To verify the correction formula is accurate, a special gage was constructed. It has a response rate of 6 ms to the first time constant. An experiment was conducted by placing the special gage next to a regular gage. The results show the faster acting gage produces a signal that matches the corrected signal of the slower gage, with one exception. The overall fluence increased. The most profound effect of this gage is realized when attempting to improve the performance of a TRS system. By realizing the capabilities of the gages, a more accurate determination of the thermal output of future TRS systems can be assessed. This will have direct impact on future Nuclear Survivability criterion by realizing the true capabilities of TRS systems.
6
Andersen, Kenneth J. "Crises to Crises: A 30-Year Retrospective on the Electric Utility Industry and Energy Efficient Lighting Technology." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-39278.
Full textAbstract:
This paper reviews the change in energy efficiency of lighting technology during the 30-year period between the energy crises of the 1970’s oil embargo and last year’s de-regulated wholesale market, electricity price spikes. Lighting power requirements have been cut in half for new commercial buildings, dropping from 3 to 1.5 watts or less per square foot of conditioned space. Fluorescent lighting technology has changed from four-foot T-12 lamps requiring 40 watts, to high-lumen, 32-watt T-8 lamps. Copper intensive and noisy magnetic ballasts have been replaced with lightweight, high frequency electronic ballasts lowering power from 10 to one watt per fixture. Today this trend continues with the movement away from Edison’s incandescent lamp to compact fluorescent lamps (CFL) that save 70% of the electrical energy. In response to the wholesale electricity prices spikes, the Northwest Energy Efficiency Alliance partnered with regional electric utilities and retail stores to offer CFL discount coupons. As a result, CFL sales rose from about 500,000 in 2000 to over 8 million in 2001. This is one more example of how energy efficiency programs sponsored by the nation’s electric utilities have driven both technology and the market to change.
7
Murai, Motohiko, and Sho Sakamoto. "A Basic Study on the Effect of Deep Learning to Determine the Control Force to Maximize the Power Generation of PA-WEC in Irregular Waves." In ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/omae2022-78521.
Full textAbstract:
Abstract As an alternative energy source to fossil fuels, marine renewable energy is expected to have a huge potential. Wave energy is one of the marine renewable energy sources. The feature of a PA-WEC, which is one of the Wave Energy Converter (WEC), can generate electricity directly from the change of magnetic field caused by the relative motion of the coil and the moving part of the floating body with permanent magnet. It is also possible to control the stiffness relation by applying a force to the moving part of the floating body by changing the current in the coil. By taking advantage of this characteristic, it is possible to generate electricity efficiently in a wide periodicity band. As for this efficient power generation, the authors have shown the analytical optimum solutions for the regular and irregular wave problems, including arrayed PA-WEC problems, for maximizing the power generation considering the copper loss in the generator. On the other hand, it is not easy to decompose the unknown irregular wave components into multiple regular wave components with high accuracy from time to time in the actual ocean. Therefore, the authors have been investigating the possibility of estimating the optimal control force at each moment in an unknown irregular wave by using an AI model. Then we showed that the AI model trained on regular waves can estimate the control force close to the theoretical solution for irregular waves. In this study, the AI model is incorporated into the equations of motion, and the time series response of the power generation is obtained in an unknown irregular wave. From the comparison with the analytical optimal solution of the power generation, the possibility of applying the AI model was investigated. As a result, it was shown that, depending on the combination of the training model and input conditions, it is possible to obtain about 70% of the power generation compared to the theoretical solution.
8
ZHOU, HONG, and JUN-GUO QIAO. "ENVIRONMENTAL PROTECTION INVESTMENT AND BUSINESS PERFORMANCE OF ENTERPRISES UNDER THE INFLUENCE OF ENVIRONMENTAL REGULATION." In 2021 International Conference on Management, Economics, Business and Information Technology. Destech Publications, Inc., 2021. http://dx.doi.org/10.12783/dtem/mebit2021/35636.
Full textAbstract:
The 11th Five-Year Plan of China has established obligatory targets for main pollutant emissions while the completion of the targets has been associated with the achievements of local officials. With the full implementation of this plan, many enterprises began to take forward-looking environmental protection strategies to cope with the increasingly stringent environmental regulations. Most of the existing literature have systematically studied the impact of environmental regulation from the perspective of industry or region, but they have not considered the dynamic response of enterprises to environmental regulation. The research on the economic consequences of enterprises adopting forward-looking environmental protection strategies for environmental protection investment at the micro level is relatively insufficient. This paper uses the data of China's listed manufacturing companies from 2011 to 2017 to study the effect of environmental protection investment on their business performance of enterprises. The results show that environmental protection investment has a positive cumulative effect on company’s business performance, especially in non-state-owned enterprises. Based on this conclusion, this paper puts forward relevant policy suggestions to promote enterprises to implement forward-looking environmental protection strategy and gain competitive advantage.
9
Shirai, Koji, Tsukasa Miyagi, Mikimasa Iwata, Koji Tasaka, and Junghoon Ji. "Demonstrative HEAF (High Energy Arcing Fault) Fire Tests of High and Low Voltage Switchgears of Nuclear Power Plants." In 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-82177.
Full textAbstract:
High Energy Arcing Faults (HEAF) have the potential to cause extensive damage to the failed electrical components and distribution systems along with adjacent equipment and cables within the zone of influence (ZOI). Furthermore, the significant energy released during HEAF event can act as an ignition source to other components within the area of the HEAF. In Japan, during the Great East Japan Earthquake occurred in 2011, the seismic induced HEAF fire event, which induced the whole damage of the multiple high voltage switchgears, was observed in Onagawa Nuclear Power Plant (NPP). In response, in August 2017, the NRA (Nuclear Regular Authority) in Japan amended the safety requirement for the power supply to consider the influence of the successive fire due to the HEAF event (hereinafter HEAF fire event). Therefore, it is urgently necessary to establish the design criteria to prevent the HEAF fire event, and enhance the experiment data of the HEAF fire event. In order to estimate the total arc energy during the HEAF event and obtain the threshold value to prevent the HEAF fire for the existed non-arc proof electrical cabinets, several series of three-phase internal arc tests with high (6.9kV class) and low (480V class) voltage electrical cabinets were executed. We executed internal arc tests with full scale high/low voltage metal-enclosed switchgear components (non-arc proof type, copper bus conductor), and evaluated arc energy, the mechanical damage of the cabinet and the surrounding equipment due to the impulsive pressure and the possibility of successive fire occurrence. In case of high voltage switchgear, when the arcing energy exceeded 25.3MJ, successive fire was identified. Especially, in the case where the arc flash was discharged in the circuit breaker room, a 2-second arcing duration in a three-phase short-circuit current with 18.9kA (measured arcing energy over 40MJ) caused successive fire which required extinguishment. On the other hand, in case of low voltage power center, when the arcing energy exceeded 19MJ, successive fire was identified. According to these demonstrative tests, this paper presents the evaluation method to estimate total arc discharge energy during the HEAF event for high and low voltage electrical cabinets.
10
Zhang, Sai, and Zhegang Ma. "Incorporating FLEX Strategies in Multi-Unit Probabilistic Risk Assessment." In 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16889.
Full textAbstract:
Abstract The catastrophic Fukushima nuclear accident reminded the nuclear community about potential extreme accident scenarios, including those involving multiple reactor units on the same site. In response to the Fukushima accident, the nuclear power industry developed and implemented a series of strategies, including Diverse and Flexible Coping Strategies (FLEX), to enhance the capacities of nuclear power plants (NPPs) to cope with extreme accidents. This study examines the impact of FLEX strategies on the overall risk from all reactor units located at the same NPP site, including risks from accidents involving either a single unit or multiple units. The fundamental, methodological element of this study is Multi-Unit Probabilistic Risk Assessment (MUPRA) requiring a shift in Probabilistic Risk Assessment (PRA) from a one-reactor-at-a-time mindset to a consideration of all reactors sharing a site. An integrated modeling approach for multi-unit event sequence development is leveraged to develop the MUPRA model and address intra-unit and inter-unit dependencies. Systems Analysis Programs for Hands-on Integrated Reliability Evaluations (SAPHIRE), a PRA software developed and maintained by Idaho National Laboratory for the United States (U.S.) Nuclear Regulatory Commission, serves as the platform for MUPRA modeling. This study selects loss of offsite power (LOOP) as a representative initiating event potentially occurring on a generic two-unit NPP site and impacting both reactor units. First, an MUPRA model, including multi-unit event trees, is developed to obtain single-unit and multi-unit accident scenarios. Next, different FLEX strategies are assumed; for example, whether FLEX equipment for multiple units can be used in a cross-connected manner. Lastly, the effectiveness of each postulated FLEX strategy is evaluated by incorporating the corresponding FLEX equipment and deployment logic into the MUPRA model.
Reports on the topic "Copper responsive regulator"
1
Prusky, Dov, Nancy P. Keller, and Amir Sherman. global regulation of mycotoxin accumulation during pathogenicity of Penicillium expansum in postharvest fruits. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7600012.bard.
Full textAbstract:
Background to the topic- Penicilliumas a postharvest pathogen and producer of the mycotoxin PAT. Penicilliumspp. are destructive phytopathogens, capable of causing decay in many deciduous fruits, during postharvest handling and storage; and the resulting losses can amount to 10% of the stored produce and the accumulation of large amounts of the mycotoxinpatulin. The overall goal of this proposal is to identify critical host and pathogen factors that modulate P. expansummycotoxin genes and pathways which are required for PAT production and virulence. Our preliminary results indicated that gluconic acid are strongly affecting patulin accumulation during colonization. P. expansumacidifies apple fruit tissue during colonization in part through secretion of gluconic acid (GLA). Several publications suggested that GLA accumulation is an essential factor in P. expansumpathogenicity. Furthermore, down regulation of GOX2 significantly reduced PAT accumulation and pathogenicity. PAT is a polyketide and its biosynthesis pathway includes a 15-gene cluster. LaeA is a global regulator of mycotoxin synthesis. It is now known that patulin synthesis might be subjected to LaeA and sometimes by environmental sensing global regulatory factors including the carbon catabolite repressor CreA as well as the pH regulator factor PacC and nitrogen regulator AreA. The mechanisms by which LaeA regulates patulin synthesis was not fully known and was part of our work. Furthermore, the regulatory system that controls gene expression in accordance with ambient pH was also included in our work. PacC protein is in an inactive conformation and is unable to bind to the promoter sites of the target genes; however, under alkaline growth conditions activated PacC acts as both an activator of alkaline-expressed genes and a repressor of acid-expressed genes. The aims of the project- This project aims to provide new insights on the roles of LaeA and PacC and their signaling pathways that lead to GLA and PAT biosynthesis and pathogenicity on the host. Specifically, our specific aims were: i) To elucidate the mechanism of pH-controlled regulation of GLA and PAT, and their contribution to pathogenesis of P. expansum. We are interested to understanding how pH and/or GLA impact/s under PacC regulation affect PAT production and pathogenesis. ii) To characterize the role of LaeA, the global regulator of mycotoxin production, and its effect on PAT and PacC activity. iii) To identify the signaling pathways leading to GLA and PAT synthesis. Using state- of-the-art RNAseq technologies, we will interrogate the transcriptomes of laeAand pacCmutants, to identify the common signaling pathways regulating synthesis of both GLA and PAT. Major conclusions, solutions, achievements- In our first Aim our results demonstrated that ammonia secreted at the leading edge of the fungal colony induced transcript activation of the global pH modulator PacC and PAT accumulation in the presence of GLA. We assessed these parameters by: (i) direct exogenous treatment of P. expansumgrowing on solid medium; (ii) direct exogenous treatment on colonized apple tissue; (iii) growth under self-ammonia production conditions with limited carbon; and (iv) analysis of the transcriptional response to ammonia of the PAT biosynthesis cluster. Ammonia induced PAT accumulation concurrently with the transcript activation of pacCand PAT biosynthesis cluster genes, indicating the regulatory effect of ammonia on pacCtranscript expression under acidic conditions. Transcriptomic analysis of pH regulated processes showed that important genes and BARD Report - Project 4773 Page 2 of 10 functionalities of P. expansumwere controlled by environmental pH. The differential expression patterns of genes belonging to the same gene family suggest that genes were selectively activated according to their optimal environmental conditions to enable the fungus to cope with varying conditions and to make optimal use of available enzymes. Concerning the second and third Aims, we demonstrated that LaeA regulates several secondary metabolite genes, including the PAT gene cluster and concomitant PAT synthesis invitro. Virulence studies of ΔlaeAmutants of two geographically distant P. expansumisolates (Pe-21 from Israel and Pe-T01 from China) showed differential reduction in disease severity in freshly harvested fruit ranging from no reduction for Ch-Pe-T01 strains in immature fruit to 15–25% reduction for both strains in mature fruit, with the ΔlaeAstrains of Is-Pe-21 always showing a greater loss in virulence. Results suggest the importance of LaeA regulation of PAT and other secondary metabolites on pathogenicity. Our work also characterized for the first time the role of sucrose, a key nutritional factor present in apple fruit, as a negative regulator of laeAexpression and consequent PAT production in vitro. This is the first report of sugar regulation of laeAexpression, suggesting that its expression may be subject to catabolite repression by CreA. Some, but not all of the 54 secondary metabolite backbone genes in the P. expansumgenome, including the PAT polyketide backbone gene, were found to be regulated by LaeA. Together, these findings enable for the first time a straight analysis of a host factor that potentially activates laeAand subsequent PAT synthesis.
2
Steffens, John C., and Eithan Harel. Polyphenol Oxidases- Expression, Assembly and Function. United States Department of Agriculture, January 1995. http://dx.doi.org/10.32747/1995.7571358.bard.
Full textAbstract:
Polyphenol oxidases (PPOs) participate in the preparation of many plant products on the one hand and cause considerable losses during processing of plant products on the other hand. However, the physiological functions of plant PPO were still a subject of controversy at the onset of the project. Preliminary observations that suggested involvement of PPOs in resistance to herbivores and pathogens held great promise for application in agriculture but required elucidation of PPO's function if modulation of PPO expression is to be considered for improving plant protection or storage and processing of plant products. Suggestions on a possible role of PPO in various aspects of chloroplast metabolism were also relevant in this context. The characterization of plant PPO genes opened a way for achieving these goals. We reasoned that "understanding PPO targeting and routing, designing ways to manipulate its expression and assessing the effects of such modifications will enable determination of the true properties of the enzyme and open the way for controlling its activity". The objective of the project was to "obtain an insight into the function and biological significance of PPOs" by examining possible function(s) of PPO in photosynthesis and plant-pest interactions using transgenic tomato plants; extending our understanding of PPO routing and assembly and the mechanism of its thylakoid translocation; preparing recombinant PPOs for use in import studies, determination of the genuine properties of PPOs and understanding its assembly and determining the effect of PPO's absence on chloroplast performance. Results obtained during work on the project made it necessary to abandon some minor objectives and devote the effort to more promising topics. Such changes are mentioned in the 'Body of the report' which is arranged according to the objectives of the original proposal. The complex expression pattern of tomato PPO gene family was determined. Individual members of the family are differentially expressed in various parts of the plant and subjected to developmentally regulated turnover. Some members are differentially regulated also by pathogens, wounding and chemical wound signals. Wounding systemically induces PPO activity and level in potato. Only tissues that are developmentally competent to express PPO are capable of responding to the systemic wounding signal by increased accumulation of PPO mRNA. Down regulation of PPO genes causes hyper susceptibility to leaf pathogens in tomato while over expression regulation of PPO expression in tomato plants is their apparent increased tolerance to drought. Both the enhanced disease resistance conferred by PPO over expression and the increased stress tolerance due to down regulation can be used in the engineering of improved crop plants. Photosynthesis rate and variable fluorescence measurements in wild type, and PPO-null and over expressing transgenic tomato lines suggest that PPO does not enable plants to cope better with stressful high light intensities or reactive oxygen species. Rather high levels of the enzyme aggravate the damage caused under such conditions. Our work suggests that PPO's primary role is in defending plants against pathogens and herbivores. Jasmonate and ethylene, and apparently also salicylate, signals involved in responses to wounding and defense against herbivores and pathogens, enhance markedly and specifically the competence of chloroplasts to import and process pPPO. The interaction of the precursor with thylakoid membranes is primarily affected. The routing of PPO shows other unusual properties: stromal processing occurs in two sites, resulting in intermediates that are translocated across thylakoids by two different mechanisms - a DpH- and a Sec-dependent one. It is suggested that the dual pattern of processing and routing constitutes a'fail safe' mechanism, reflecting the need for a rapid and flexible response to defense challenges. Many of the observations described above should be taken into consideration when manipulation of PPO expression is contemplated for use in crop improvement.
3
Yahav, Shlomo, John McMurtry, and Isaac Plavnik. Thermotolerance Acquisition in Broiler Chickens by Temperature Conditioning Early in Life. United States Department of Agriculture, 1998. http://dx.doi.org/10.32747/1998.7580676.bard.
Full textAbstract:
The research on thermotolerance acquisition in broiler chickens by temperature conditioning early in life was focused on the following objectives: a. To determine the optimal timing and temperature for inducing the thermotolerance, conditioning processes and to define its duration during the first week of life in the broiler chick. b. To investigate the response of skeletal muscle tissue and the gastrointestinal tract to thermal conditioning. This objective was added during the research, to understand the mechanisms related to compensatory growth. c. To evaluate the effect of early thermo conditioning on thermoregulation (heat production and heat dissipation) during 3 phases: (1) conditioning, (2) compensatory growth, (3) heat challenge. d. To investigate how induction of improved thermotolerance impacts on metabolic fuel and the hormones regulating growth and metabolism. Recent decades have seen significant development in the genetic selection of the meat-type fowl (i.e., broiler chickens); leading to rapid growth and increased feed efficiency, providing the poultry industry with heavy chickens in relatively short growth periods. Such development necessitates parallel increases in the size of visceral systems such as the cardiovascular and the respiratory ones. However, inferior development of such major systems has led to a relatively low capability to balance energy expenditure under extreme conditions. Thus, acute exposure of chickens to extreme conditions (i.e., heat spells) has resulted in major economic losses. Birds are homeotherms, and as such, they are able to maintain their body temperature within a narrow range. To sustain thermal tolerance and avoid the deleterious consequences of thermal stresses, a direct response is elicited: the rapid thermal shock response - thermal conditioning. This technique of temperature conditioning takes advantage of the immaturity of the temperature regulation mechanism in young chicks during their first week of life. Development of this mechanism involves sympathetic neural activity, integration of thermal infom1ation in the hypothalamus, and buildup of the body-to-brain temperature difference, so that the potential for thermotolerance can be incorporated into the developing thermoregulation mechanisms. Thermal conditioning is a unique management tool, which most likely involves hypothalamic them1oregulatory threshold changes that enable chickens, within certain limits, to cope with acute exposure to unexpected hot spells. Short-tem1 exposure to heat stress during the first week of life (37.5+1°C; 70-80% rh; for 24 h at 3 days of age) resulted in growth retardation followed immediately by compensatory growth" which resulted in complete compensation for the loss of weight gain, so that the conditioned chickens achieved higher body weight than that of the controls at 42 days of age. The compensatory growth was partially explained by its dramatic positive effect on the proliferation of muscle satellite cells which are necessary for further muscle hypertrophy. By its significant effect of the morphology and functioning of the gastrointestinal tract during and after using thermal conditioning. The significant effect of thermal conditioning on the chicken thermoregulation was found to be associated with a reduction in heat production and evaporative heat loss, and with an increase in sensible heat loss. It was further accompanied by changes in hormones regulating growth and metabolism These physiological responses may result from possible alterations in PO/AH gene expression patterns (14-3-3e), suggesting a more efficient mechanism to cope with heat stress. Understanding the physiological mechanisms behind thermal conditioning step us forward to elucidate the molecular mechanism behind the PO/AH response, and response of other major organs. The thermal conditioning technique is used now in many countries including Israel, South Korea, Australia, France" Ecuador, China and some places in the USA. The improvement in growth perfom1ance (50-190 g/chicken) and thermotolerance as a result of postnatal thermal conditioning, may initiate a dramatic improvement in the economy of broiler's production.
4
Chen, Junping, Zach Adam, and Arie Admon. The Role of FtsH11 Protease in Chloroplast Biogenesis and Maintenance at Elevated Temperatures in Model and Crop Plants. United States Department of Agriculture, May 2013. http://dx.doi.org/10.32747/2013.7699845.bard.
Full textAbstract:
specific objectives of this proposal were to: 1) determine the location, topology, and oligomerization of FtsH11 protease; 2) identify the substrate/s of FtsH11 and the downstream components involved in maintaining thermostability of chloroplasts; 3) identify new elements involved in FtsH11 protease regulatory network related to HT adaptation processes in chloroplast; 4) Study the role of FtsH11 homologs from crop species in HT tolerance. Background to the topic: HT-tolerant varieties that maintain high photosynthetic efficiency at HT, and cope better with daily and seasonal temperature fluctuations are in great need to alleviate the effect of global warming on food production. Photosynthesis is a very complex process requiring accurate coordination of many complex systems and constant adjustments to the changing environments. Proteolytic activities mediated by various proteases in chloroplast are essential part of this process and critical for maintaining normal chloroplast functions under HT. However, little is known about mechanisms that contribute to adaptation of photosynthetic processes to HT. Our study has shown that a chloroplast-targeted Arabidopsis FtsH11 protease plays an essential and specific role in maintaining thermostability of thylakoids and normal photosynthesis at moderate HT. We hypothesized that FtsH11 homologs recently identified in other plant species might have roles similarly to that of AtFtsH1. Thus, dissecting the underlying mechanisms of FtsH11 in the adaptation mechanisms in chloroplasts to HT stress and other elements involved will aid our effort to produce more agricultural products in less favorable environments. Major conclusions, solutions, achievements - Identified the chloroplast inner envelope membrane localization of FtsH11. - Revealed a specific association of FtsH11 with the a and b subunits of CPN60. - Identified the involvement of ARC6, a protein coordinates chloroplast division machineries in plants, in FtsH11 mediated HT adaptation process in chloroplast. -Reveal possible association of a polyribonucleotide nucleotidyltransferase (cpPNPase), coded by At3G03710, with FtsH11 mediated HT adaptation process in chloroplast. - Mapped 4 additional loci in FtsH11 mediated HT adaptation network in chloroplast. - Demonstrated importance of the proteolytic activity of FtsH11 for thermotolerance, in addition to the ATPase activity. - Demonstrated a conserved role of plant FtsH11 proteases in chloroplast biogenesis and in maintaining structural and functional thermostability of chloroplast at elevated temperatures. Implications, both scientific and agricultural:Three different components interacting with FtsH11 were identified during the course of this study. At present, it is not known whether these proteins are directly involved in FtsH11mediated thermotolerance network in chloroplast and/or how these elements are interrelated. Studies aiming to connect the dot among biological functions of these networks are underway in both labs. Nevertheless, in bacteria where it was first studied, FtsH functions in heat shock response by regulating transcription level of σ32, a heat chock factor regulates HSPsexpression. FtsH also involves in control of biosynthesis of membrane components and quality control of membrane proteins etc. In plants, both Arc 6 and CPN60 identified in this study are essential in chloroplast division and developments as mutation of either one impairs chloroplast division in Arabidopsis. The facts that we have found the specific association of both α and β CPN60 with FtsH11 protein biochemically, the suppression/ enhancement of ftsh11 thermosensitive phenotype by arc6 /pnp allele genetically, implicate inter-connection of these networks via FtsH11 mediated network(s) in regulating the dynamic adaptation processes of chloroplast to temperature increases at transcriptional, translational and post-translational levels. The conserved role of FtsH11 proteases in maintaining thermostability of chloroplast at HT demonstrated here provides a foundation for improving crop photosynthetic performance at high temperatures.
5
Phillips, Jake. Understanding the impact of inspection on probation. Sheffield Hallam University, 2021. http://dx.doi.org/10.7190/shu.hkcij.05.2021.
Full textAbstract:
This research sought to understand the impact of probation inspection on probation policy, practice and practitioners. This important but neglected area of study has significant ramifications because the Her Majesty’s Inspectorate of Probation has considerable power to influence policy through its inspection regime and research activities. The study utilised a mixed methodological approach comprising observations of inspections and interviews with people who work in probation, the Inspectorate and external stakeholders. In total, 77 people were interviewed or took part in focus groups. Probation practitioners, managers and leaders were interviewed in the weeks after an inspection to find out how they experienced the process of inspection. Staff at HMI Probation were interviewed to understand what inspection is for and how it works. External stakeholders representing people from the voluntary sector, politics and other non-departmental bodies were interviewed to find out how they used the work of inspection in their own roles. Finally, leaders within the National Probation Service and Her Majesty’s Prisons and Probation Service were interviewed to see how inspection impacts on policy more broadly. The data were analysed thematically with five key themes being identified. Overall, participants were positive about the way inspection is carried out in the field of probation. The main findings are: 1. Inspection places a burden on practitioners and organisations. Practitioners talked about the anxiety that a looming inspection created and how management teams created additional pressures which were hard to cope with on top of already high workloads. Staff responsible for managing the inspection and with leadership positions talked about the amount of time the process of inspection took up. Importantly, inspection was seen to take people away from their day jobs and meant other priorities were side-lined, even if temporarily. However, the case interviews that practitioners take part in were seen as incredibly valuable exercises which gave staff the opportunity to reflect on their practice and receive positive feedback and validation for their work. 2. Providers said that the findings and conclusions from inspections were often accurate and, to some extent, unsurprising. However, they sometimes find it difficult to implement recommendations due to reports failing to take context into account. Negative reports have a serious impact on staff morale, especially for CRCs and there was concern about the impact of negative findings on a provider’s reputation. 3. External stakeholders value the work of the Inspectorate. The Inspectorate is seen to generate highly valid and meaningful data which stakeholders can use in their own roles. This can include pushing for policy reform or holding government to account from different perspectives. In particular, thematic inspections were seen to be useful here. 4. The regulatory landscape in probation is complex with an array of actors working to hold providers to account. When compared to other forms of regulation such as audit or contract management the Inspectorate was perceived positively due to its methodological approach as well as the way it reflects the values of probation itself. 5. Overall, the inspectorate appears to garner considerable legitimacy from those it inspects. This should, in theory, support the way it can impact on policy and practice. There are some areas for development here though such as more engagement with service users. While recognising that the Inspectorate has made a concerted effort to do this in the last two years participants all felt that more needs to be done to increase that trust between the inspectorate and service users. Overall, the Inspectorate was seen to be independent and 3 impartial although this belief was less prevalent amongst people in CRCs who argued that the Inspectorate has been biased towards supporting its own arguments around reversing the now failed policy of Transforming Rehabilitation. There was some debate amongst participants about how the Inspectorate could, or should, enforce compliance with its recommendations although most people were happy with the primarily relational way of encouraging compliance with sanctions for non-compliance being considered relatively unnecessary. To conclude, the work of the Inspectorate has a significant impact on probation policy, practice and practitioners. The majority of participants were positive about the process of inspection and the Inspectorate more broadly, notwithstanding some of the issues raised in the findings. There are some developments which the Inspectorate could consider to reduce the burden inspection places on providers and practitioners and enhance its impact such as amending the frequency of inspection, improving the feedback given to practitioners and providing more localised feedback, and working to reduce or limit perceptions of bias amongst people in CRCs. The Inspectorate could also do more to capture the impact it has on providers and practitioners – both positive and negative - through existing procedures that are in place such as post-case interview surveys and tracking the implementation of recommendations.