| 1. |
- Drottz-Sjöberg, Britt-Marie, et al.
(författare)
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Knowledge and risk perception among nuclear power plant employees
- 1991
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Ingår i: Risk Analysis. - : Wiley: 24 months. - 1539-6924 .- 0272-4332. ; 11:4, s. 607-618
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This is a study of knowledge, risk perception, and attitudes among nuclear power plant employees. A total of 236 persons participated, belonging to 10 different professional groups and working at two Swedish power plants. Job-related radiation risks were judged about average as compared to a number of other risks. On the whole, the participants in the study were satisfied with the measures of safety at work, but there were some exceptions to this rule, especially among those hired for temporary jobs through external contractors. The experience of job-related radiation risks was related to the level of knowledge about radiation and its risks: those who knew less experienced larger risks. General level of anxiety did not correlate with risk perception. The latter was accounted for mainly by perceived radiation risks. Job satisfaction was more strongly related to perceived conventional job risks than to nuclear risks. Risk ratings were related to how subjects defined the concept of risk. Those who stressed consequences as part of their risk definition gave higher risk ratings.
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| 2. |
- Drottz-Sjöberg, Britt-Marie, et al.
(författare)
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Psychological reactions to cancer risks after the Chernobyl accident
- 1987
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Ingår i: Medical Oncology. - : Humana Press. - 1559-131X .- 1357-0560. ; 4:3-4, s. 259-271
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Tidskriftsartikel (refereegranskat)abstract
- This is a report on an investigation of people's reactions to the Chernobyl accident. Interviews and, mail surveys were conducted in July-September 1986 with pregnant women, parents of newborn children, farmers, adolescents and men who were not parents, in various areas of Sweden, differing as to the amount of Chernobyl fallout they had received. The accident had probably doubled the number of people who were negative to nuclear power in the most affected area. Radiation risks were highly salient in most groups. Areas differed in the expected direction, people in the more, exposed areas being more concerned. Women were more worried and more negative to nuclear power than men while adolescents appeared to be the group least affected by the accident. Farmers were also strongly opposed to nuclear power and concerned about its risks. Nuclear attitude could be well accounted for by attitude statements and rated basic life values. It was quite stable over a 1 month period.
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| 3. |
- Drottz-Sjöberg, Britt-Marie, et al.
(författare)
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Risk perception and worries after the Chernobyl accident
- 1990
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Ingår i: Journal of Environmental Psychology. - : Elsevier. - 0272-4944. ; 10:2, s. 135-149
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Tidskriftsartikel (refereegranskat)abstract
- This is a study of reactions in selected groups of the Swedish population to the Chernobyl accident. Data were collected in September 1986, from 3 regions in the country which had been exposed in various degrees to radioactive fallout. In each region samples of farmers, adolescents, persons who had had a child just before or after the accident, and men who were not registered as legal custodians of children, were approached with a mail questionnaire. It was found that attitudes to nuclear power were predominantly negative, that the risks associated with radiation and nuclear power were rated among the worst risks, and that residents of the most exposed region (Gavle) reported being worried about injury from radiation twice as often as others. A sub-group of decisive opponents of nuclear power was identified. It was 15 times larger than the corresponding sub-group of decisive proponents. New parents and farmers were quite negative to nuclear power, a finding discussed in relation to their responsibilities for food production and care for others.
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| 4. |
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| 5. |
- Sjöberg, Lennart, et al.
(författare)
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Adolescents' attitudes to nuclear power and radioactive wastes
- 1991
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Ingår i: Journal of Applied Social Psychology. - : Wiley: 12 months. - 1559-1816 .- 0021-9029. ; 21:24, s. 2007-2036
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Tidskriftsartikel (refereegranskat)abstract
- High school students (N = 380) reported their attitude to nuclear power and rated various risks: nuclear and non-nuclear, personal and societal. The focus of the study concerned risks related to handling and disposal of radioactive waste. It was found that conventional personal risks obtained lower risk ratings than risks to society and risks related to accidents in the handling and disposal of radioactive waste. In general, items which made reference to radiation were rated higher than items which did not mention this aspect. Female students most often rated risk higher than did male students. Persons worried about nuclear power emphasized risks of accidents and waste disposal as problems, whereas those who did not worry trusted those in charge and saw nuclear power as quite safe, stressing its basis in advanced technological knowledge and skill, Students specializing in economics or technology were the least concerned about nuclear power risks and had the most positive attitudes to nuclear power. The results of the study are discussed in relation to risk perception discrepancies of experts and the public. We suggest that future experts will be recruited from groups that have, already in adolescence, established beliefs about nuclear technology risks that are lower than those of other groups. Compared to a national sample dominated by adults, the adolescents, especially boys, held more positive attitudes to nuclear power and rated risks of nuclear technology lower than adults.
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| 6. |
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| 7. |
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| 8. |
- Andersson, Martin E, et al.
(författare)
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Structural and mutational studies of the carboxylate cluster in iron-free ribonucleotide reductase R2.
- 2004
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Ingår i: Biochemistry. - 0006-2960. ; 43:24, s. 7966-72
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Tidskriftsartikel (refereegranskat)abstract
- The R2 protein of ribonucleotide reductase features a di-iron site deeply buried in the protein interior. The apo form of the R2 protein has an unusual clustering of carboxylate side chains at the empty metal-binding site. In a previous study, it was found that the loss of the four positive charge equivalents of the diferrous site in the apo protein appeared to be compensated for by the protonation of two histidine and two carboxylate side chains. We have studied the consequences of removing and introducing charged residues on the local hydrogen-bonding pattern in the region of the carboxylate cluster of Corynebacterium ammoniagenes and Escherichia coli protein R2 using site-directed mutagenesis and X-ray crystallography. The structures of the metal-free forms of wild-type C. ammoniagenes R2 and the mutant E. coli proteins D84N, S114D, E115A, H118A, and E238A have been determined and their hydrogen bonding and protonation states have been structurally assigned as far as possible. Significant alterations to the hydrogen-bonding patterns, protonation states, and hydration is observed for all mutant E. coli apo proteins as compared to wild-type apo R2. Further structural variations are revealed by the wild-type apo C. ammoniagenes R2 structure. The protonation and hydration effects seen in the carboxylate cluster appear to be due to two major factors: conservation of the overall charge of the site and the requirement of electrostatic shielding of clustered carboxylate residues. Very short hydrogen-bonding distances between some protonated carboxylate pairs are indicative of low-barrier hydrogen bonding.
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| 9. |
- Aurelius, Oskar, et al.
(författare)
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The Crystal Structure of Thermotoga maritima Class III Ribonucleotide Reductase Lacks a Radical Cysteine Pre-Positioned in the Active Site
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- Ribonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides to deoxyribonucleotides, the building blocks for DNA synthesis, and are found in all but a few organisms. RNRs use radical chemistry to catalyze the reduction reaction. Despite RNR having evolved several mechanisms for generation of different kinds of essential radicals across a large evolutionary time frame, this initial radical is normally always channelled to a strictly conserved cysteine residue directly adjacent to the substrate for initiation of substrate reduction, and this cysteine has been found in the structures of all RNRs solved to date. We present the crystal structure of an anaerobic RNR from the extreme thermophile Thermotoga maritima (tmNrdD), alone and in several complexes, including with the allosteric effector dATP and its cognate substrate CTP. In the crystal structure of the enzyme as purified, tmNrdD lacks a cysteine for radical transfer to the substrate pre-positioned in the active site. Nevertheless activity assays using anaerobic cell extracts from T. maritima demonstrate that the class III RNR is enzymatically active. Other genetic and microbiological evidence is summarized indicating that the enzyme is important for T. maritima. Mutation of either of two cysteine residues in a disordered loop far from the active site results in inactive enzyme. We discuss the possible mechanisms for radical initiation of substrate reduction given the collected evidence from the crystal structure, our activity assays and other published work. Taken together, the results suggest either that initiation of substrate reduction may involve unprecedented conformational changes in the enzyme to bring one of these cysteine residues to the expected position, or that alternative routes for initiation of the RNR reduction reaction may exist. Finally, we present a phylogenetic analysis showing that the structure of tmNrdD is representative of a new RNR subclass IIIh, present in all Thermotoga species plus a wider group of bacteria from the distantly related phyla Firmicutes, Bacteroidetes and Proteobacteria.
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| 10. |
- Berggren, Gustav, et al.
(författare)
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Compounds with capacity to quench the tyrosyl radical in Pseudomonas aeruginosa ribonucleotide reductase
- 2019
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Ingår i: Journal of Biological Inorganic Chemistry. - : Springer Science and Business Media LLC. - 0949-8257 .- 1432-1327. ; 24:6, s. 841-848
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Tidskriftsartikel (refereegranskat)abstract
- Ribonucleotide reductase (RNR) has been extensively probed as a target enzyme in the search for selective antibiotics. Here we report on the mechanism of inhibition of nine compounds, serving as representative examples of three different inhibitor classes previously identified by us to efficiently inhibit RNR. The interaction between the inhibitors and Pseudomonas aeruginosa RNR was elucidated using a combination of electron paramagnetic resonance spectroscopy and thermal shift analysis. All nine inhibitors were found to efficiently quench the tyrosyl radical present in RNR, required for catalysis. Three different mechanisms of radical quenching were identified, and shown to depend on reduction potential of the assay solution and quaternary structure of the protein complex. These results form a good foundation for further development of P. aeruginosa selective antibiotics. Moreover, this study underscores the complex nature of RNR inhibition and the need for detailed spectroscopic studies to unravel the mechanism of RNR inhibitors.
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| 11. |
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| 12. |
- Berggren, Gustav, et al.
(författare)
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Semiquinone-induced Maturation of Bacillus anthracis Ribonucleotide Reductase by a Superoxide Intermediate
- 2014
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 289:46, s. 31940-31949
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Tidskriftsartikel (refereegranskat)abstract
- Background: Activation of ribonucleotide reductase Ib depends on the flavodoxin-like maturase NrdI.Results: The redox properties of Bacillus anthracis NrdI allow isolation of the semiquinone state, NrdI(sq), which can catalyze formation of the manganese-tyrosyl radical cofactor.Conclusion: The maturation capacity of NrdI(sq) provides evidence that Mn-NrdF is activated via a superoxide radical.Significance: Novel antibiotics may be designed to selectively target the maturation mechanism.
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| 13. |
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| 14. |
- Berner, Boel, 1945-, et al.
(författare)
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Inledning
- 2008
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Ingår i: Samhällsforskning 2008. Betydelsen för människorna, hembygden och regionen av ett slutförvar för använt kärnbränsle. - Stockholm : SKB.
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Bokkapitel (populärvet., debatt m.m.)
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| 15. |
- Berner, Boel, 1945-, et al.
(författare)
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Inledning
- 2007
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Ingår i: Samhällsforskning 2007. Betydelsen för människorna, hembygden och regionen av ett slutförvar för använt kärnbränsle. - Stockholm : SKB.
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Bokkapitel (populärvet., debatt m.m.)abstract
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| 16. |
- Berner, Boel, 1945-, et al.
(författare)
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Inledning
- 2006
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Ingår i: Samhällsforskning 2006. Betydelsen för människorna, hembygden och regionen av ett slutförvar för använt kärnbränsle. - Stockholm : SKB.
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Bokkapitel (populärvet., debatt m.m.)abstract
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| 17. |
- Berner, Boel, 1945-, et al.
(författare)
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Inledning
- 2005
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Ingår i: Samhällsforskning 2005. Betydelsen för människorna, hembygden och regionen av ett slutförvar för använt kärnbränsle. - Stockholm : SKB. - 9197560634
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Bokkapitel (populärvet., debatt m.m.)
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| 18. |
- Berner, Boel, et al.
(författare)
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Introduktion
- 2009
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Ingår i: Samhällsforskning 2009. - Stockholm : SKB. - 9789197786287 ; , s. 4-17
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Bokkapitel (populärvet., debatt m.m.)
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| 19. |
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| 20. |
- Berner, Boel, 1945-, et al.
(författare)
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Social Science Research 2004-2010 : Themes, results and reflections (on nuclear waste issues)
- 2011
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Denna skrift är upplagd på följande sätt. Efter detta introduktionskapitel ger vi i kapitel 2 en presentation av de viktigaste resultaten inom de fyra områdena: Socioekonomisk påverkan – samhällsekonomiska effekter, Beslutsprocesser – governance, Opinioner och attityder – psykosociala effekter samt Omvärldsförändringar. Vi sammanfattar här de olika projektens bidrag (för presentationer av respektive projekt, se bilaga 2). För originalarbeten, rapporter och andra publikationer inom programmet se litteraturlistan i bilaga 7 eller SKB:s webbplats.I kapitel 3 för vi sedan ett mer diskuterande resonemang kring några centrala teman av betydelse för förståelsen av kärnavfallsfrågans sociala och samhälleliga konsekvenser. Det är teman som aktualiserats av och även belysts i de olika projekten. Vi har valt att fokusera på frågor om samhälleliga förändringsmönster, om olika bilder av nyttan av ett slutförvar för använt kärnbränsle och risker i lokalsamhället och nationellt, på opinioner och attityder på olika nivåer, samt på slutförvarets långsiktiga betydelse. Vi tar upp dessa frågor som just frågor, för fortsatt forskning och diskussion. I kapitel 4 ges slutligen en sammanfattande värdering av samhällsprogrammets verksamhet och behoven av framtida forskning.I bilagorna 4–6 ges en bild av situationen i världen beträffande kärnkraft och avfallshantering.
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| 21. |
- Bimai, Ornella, et al.
(författare)
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Nucleotide binding to the ATP-cone in anaerobic ribonucleotide reductases allosterically regulates activity by modulating substrate binding
- 2024
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- A small, nucleotide-binding domain, the ATP-cone, is found at the N- terminus of most ribonucleotide reductase (RNR) catalytic subunits. By binding adenosine triphosphate (ATP) or deoxyadenosine triphosphate (dATP) it regulates the enzyme activity of all classes of RNR. Functional and structural work on aerobic RNRs has revealed a plethora of ways in which dATP inhibits activity by inducing oligomerisation and preventing a productive radical transfer from one subunit to the active site in the other. Anaerobic RNRs, on the other hand, store a stable glycyl radical next to the active site and the basis for their dATP-dependent inhibition is completely unknown. We present biochemical, biophysical, and structural information on the effects of ATP and dATP binding to the anaerobic RNR from Prevotella copri. The enzyme exists in a dimertetramer equilibrium biased towards dimers when two ATP molecules are bound to the ATP- cone and tetramers when two dATP molecules are bound. In the presence of ATP, P. copri NrdD is active and has a fully ordered glycyl radical domain ( GRD) in one monomer of the dimer. Binding of dATP to the ATP-cone results in loss of activity and increased dynamics of the GRD, such that it cannot be detected in the cryo-EM structures. The glycyl radical is formed even in the dATP-bound form, but the substrate does not bind. The structures implicate a complex network of interactions in activity regulation that involve the GRD more than 30 A away from the dATP molecules, the allosteric substrate specificity site and a conserved but previously unseen flap over the active site. Taken together, the results suggest that dATP inhibition in anaerobic RNRs acts by increasing the flexibility of the flap and GRD, thereby preventing both substrate binding and radical mobilisation.
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| 22. |
- Brännvall, Mathias, 1973-
(författare)
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Metal ion cooperativity in Escherichia coli RNase P RNA
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- RNase P is an essential ribonuclease responsible for removal of the 5’ leader of tRNA precursors. Bacterial RNase P consists of an RNA subunit and a small basic protein. The catalytic activity is associated with the RNA subunit, i.e. bacterial RNase P RNA is a ribozyme. The protein subunit is, however, essential for activity in vivo. RNase P RNA, as well as the holoenzyme, requires the presence of divalent metal ions for activity. The aim of this thesis was to increase our understanding of the catalytic mechanism of RNase P RNA mediated cleavage. The importance of the nucleotides close to the cleavage site and the roles of divalent metal ions in RNase P RNA-catalyzed reaction were investigated. Escherichia coli RNase P RNA (M1 RNA) was used as a model system.It was shown that different metal ions have differential effects on cleavage site recognition. Cleavage activity was rescued by mixing metal ions that do not promote cleavage activity by themselves. This suggests that efficient and correct cleavage is the result of metal ion cooperativity in the RNase P RNA-mediated cleavage reaction. The results suggested that one of the metal ions involved in this cooperativity is positioned in the vicinity of a well-known interaction between RNase P RNA and its substrate. Based on my studies on how different metal ions bind to RNA and influence its activity we raise the interesting possibility that the activity of biocatalysts that depend on RNA for activity are up- or downregulated depending on the intracellular concentrations of the bulk biological metal ions Mg2+ and Ca2+.The nucleotides upstream of the cleavage site in the substrate were found to influence the cleavage efficiency. This was not exclusively due to intermolecular base pairing within the substrate but also dependent on the identities of the nucleotides at position –2 and –1. The strength of the base pair at position –1/+73 was demonstrated to affect cleavage efficiency. These observations are in keeping with previous suggestion that the nucleotides close to the cleavage site are important for RNase P cleavage. We conclude that the residue at -1 is a positive determinant for cleavage by RNase P. Hence, my studies extend our understanding of the RNase P cleavage site recognition process.
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| 23. |
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| 24. |
- Crona, Mikael, et al.
(författare)
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A Rare Combination of Ribonucleotide Reductases in the Social Amoeba Dictyostelium discoideum
- 2013
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 288:12, s. 8198-8208
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Tidskriftsartikel (refereegranskat)abstract
- Ribonucleotide reductases (RNRs) catalyze the only pathway for de novo synthesis of deoxyribonucleotides needed for DNA replication and repair. The vast majority of eukaryotes encodes only a class I RNR, but interestingly some eukaryotes, including the social amoeba Dictyostelium discoideum, encode both a class I and a class II RNR. The amino acid sequence of the D. discoideum class I RNR is similar to other eukaryotic RNRs, whereas that of its class II RNR is most similar to the monomeric class II RNRs found in Lactobacillus spp. and a few other bacteria. Here we report the first study of RNRs in a eukaryotic organism that encodes class I and class II RNRs. Both classes of RNR genes were expressed in D. discoideum cells, although the class I transcripts were more abundant and strongly enriched during mid-development compared with the class II transcript. The quaternary structure, allosteric regulation, and properties of the diiron-oxo/radical cofactor of D. discoideum class I RNR are similar to those of the mammalian RNRs. Inhibition of D. discoideum class I RNR by hydroxyurea resulted in a 90% reduction in spore formation and decreased the germination viability of the surviving spores by 75%. Class II RNR could not compensate for class I inhibition during development, and an excess of vitamin B12 coenzyme, which is essential for class II activity, did not improve spore formation. We suggest that class I is the principal RNR during D. discoideum development and growth and is important for spore formation, possibly by providing dNTPs for mitochondrial replication.
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| 25. |
- Crona, Mikael, 1981-, et al.
(författare)
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Assembly of a fragmented ribonucleotide reductase by protein interaction domains derived from a mobile genetic element
- 2011
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Ingår i: Nucleic Acids Research. - : Oxford University Press. - 0305-1048 .- 1362-4962. ; 39:4, s. 1381-1389
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Tidskriftsartikel (refereegranskat)abstract
- Ribonucleotide reductase (RNR) is a critical enzyme of nucleotide metabolism, synthesizing precursors for DNA replication and repair. In prokaryotic genomes, RNR genes are commonly targeted by mobile genetic elements, including free standing and intron-encoded homing endonucleases and inteins. Here, we describe a unique molecular solution to assemble a functional product from the RNR large subunit gene, nrdA that has been fragmented into two smaller genes by the insertion of mobE, a mobile endonuclease. We show that unique sequences that originated during the mobE insertion and that are present as C- and N-terminal tails on the split NrdA-a and NrdA-b polypeptides, are absolutely essential for enzymatic activity. Our data are consistent with the tails functioning as protein interaction domains to assemble the tetrameric (NrdA-a/NrdA-b)2 large subunit necessary for a functional RNR holoenzyme. The tails represent a solution distinct from RNA and protein splicing or programmed DNA rearrangements to restore function from a fragmented coding region and may represent a general mechanism to neutralize fragmentation of essential genes by mobile genetic elements.
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