| 1. |
- Reverté, Sara, et al.
(författare)
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National records of 3000 European bee and hoverfly species : A contribution to pollinator conservation
- 2023
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Ingår i: Insect Conservation and Diversity. - 1752-458X. ; 16:6, s. 758-775
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Tidskriftsartikel (refereegranskat)abstract
- Pollinators play a crucial role in ecosystems globally, ensuring the seed production of most flowering plants. They are threatened by global changes and knowledge of their distribution at the national and continental levels is needed to implement efficient conservation actions, but this knowledge is still fragmented and/or difficult to access. As a step forward, we provide an updated list of around 3000 European bee and hoverfly species, reflecting their current distributional status at the national level (in the form of present, absent, regionally extinct, possibly extinct or non-native). This work was attainable by incorporating both published and unpublished data, as well as knowledge from a large set of taxonomists and ecologists in both groups. After providing the first National species lists for bees and hoverflies for many countries, we examine the current distributional patterns of these species and designate the countries with highest levels of species richness. We also show that many species are recorded in a single European country, highlighting the importance of articulating European and national conservation strategies. Finally, we discuss how the data provided here can be combined with future trait and Red List data to implement research that will further advance pollinator conservation.
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| 2. |
- Andoralov, Victor, et al.
(författare)
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Octaheme nitrite reductase : The mechanism of intramolecular electron transfer and kinetics of nitrite bioelectroreduction.
- 2021
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Ingår i: Bioelectrochemistry. - : Elsevier. - 1567-5394 .- 1878-562X. ; 138
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Tidskriftsartikel (refereegranskat)abstract
- Detailed impedance and voltammetric studies of hexameric octaheme nitrite reductase immobilized on carbon-based nanomaterials, specifically nanotubes and nanoparticles, were performed. Well-pronounced bioelectrocatalytic reduction of nitrite on enzyme-modified electrodes was obtained. Analysis of the impedance data indicated the absence of long-lived intermediates involved in the nitrite reduction. Cyclic voltammograms of biomodified electrodes had a bi-sigmoidal shape, which pointed to the presence of two enzyme orientations on carbon supports. The maximum (limiting) catalytic currents were determined and, by applying the correction by the mixed kinetics equation, the Tafel dependences were plotted for each catalytic wave/each enzyme orientation. Finally, two schemes for the rate-limiting processes during bioelectrocatalysis were proposed, viz. for low- and high-potential orientations.
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| 3. |
- Osipov, Evgeny, et al.
(författare)
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Effect of the L499M mutation of the ascomycetous Botrytis aclada laccase on redox potential and catalytic properties
- 2014
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Ingår i: Acta Crystallographica Section D. - : International Union of Crystallography. - 0907-4449 .- 1399-0047. ; 70:11, s. 2913-2923
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Tidskriftsartikel (refereegranskat)abstract
- Laccases are members of a large family of multicopper oxidases that catalyze the oxidn. of a wide range of org. and inorg. substrates accompanied by the redn. of dioxygen to water. These enzymes contain four Cu atoms per mol. organized into three sites: T1, T2 and T3. In all laccases, the T1 copper ion is coordinated by two histidines and one cysteine in the equatorial plane and is covered by the side chains of hydrophobic residues in the axial positions. The redox potential of the T1 copper ion influences the enzymic reaction and is detd. by the nature of the axial ligands and the structure of the second coordination sphere. In this work, the laccase from the ascomycete Botrytis aclada was studied, which contains conserved Ile491 and nonconserved Leu499 residues in the axial positions. The three-dimensional structures of the wild-type enzyme and the L499M mutant were detd. by X-ray crystallog. at 1.7 Å resoln. Crystals suitable for X-ray anal. could only be grown after deglycosylation. Both structures did not contain the T2 copper ion. The catalytic properties of the enzyme were characterized and the redox potentials of both enzyme forms were detd.: E 0 = 720 and 580 mV for the wild-type enzyme and the mutant, resp. Since the structures of the wild-type and mutant forms are very similar, the change in the redox potential can be related to the L499M mutation in the T1 site of the enzyme.
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| 4. |
- Scheiblbrandner, Stefan, et al.
(författare)
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Evolving stability and pH-dependent activity of the high redox potential Botrytis aclada laccase for enzymatic fuel cells
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Fungal high redox potential laccases are proposed as cathodic biocatalysts in implantable enzymatic fuel cells to generate high cell voltages. Their application is limited mainly through their acidic pH optimum and chloride inhibition. This work investigates evolutionary and engineering strategies to increase the pH optimum of a chloride-tolerant, high redox potential laccase from the ascomycete Botrytis aclada. The laccase was subjected to two rounds of directed evolution and the clones screened for increased stability and activity at pH 6.5. Beneficial mutation sites were investigated by semi-rational and combinatorial mutagenesis. Fourteen variants were characterised in detail to evaluate changes of the kinetic constants. Mutations increasing thermostability were distributed over the entire structure. Among them, T383I showed a 2.6-fold increased half-life by preventing the loss of the T2 copper through unfolding of a loop. Mutations affecting the pH-dependence cluster around the T1 copper and categorise in three types of altered pH profiles: pH-type I changes the monotonic decreasing pH profile into a bell-shaped profile, pH-type II describes increased specific activity below pH 6.5, and pH-type III increased specific activity above pH 6.5. Specific activities of the best variants were up to 5-fold higher (13 U mg(-1)) than BaL WT at pH 7.5.
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| 5. |
- Trevisan, Marco, et al.
(författare)
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Patterns of chronic and transient hyperkalaemia and clinically important outcomes in patients with chronic kidney disease
- 2022
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Ingår i: Clinical Kidney Journal. - : Oxford University Press. - 2048-8505 .- 2048-8513. ; 15:1, s. 153-161
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Tidskriftsartikel (refereegranskat)abstract
- Background: Whether hyperkalaemia in CKD is chronic or transient, and whether this has different outcome implications, is not known.Methods: This was an observational study of adults with CKD G3-5 from Stockholm, Sweden 2006-11. We examined individual trajectories of potassium from all measurements obtained through routine outpatient care. For each month of follow-up, we created a rolling assessment of the proportion of time in which potassium was abnormal during the previous 12 months. We defined patterns of hyperkalaemia as transient (<= 50% of time during the previous year with potassium >5.0 mmol/L) and chronic (>50% of time with potassium >5.0mmol/L), and examined whether previous hyperkalaemia pattern offers additional predictive value beyond that provided by the most recent (current) potassium value.Results: We included 36 511 participants (56% women) with CKD G3-5 and median estimated glomerular filtration rate 46 mL/min/1.73m(2). Transient and chronic hyperkalaemia, respectively, were observed in 15% and 4% of patients with CKD G3a, and in 50% and 17% of patients with CKD G5. In fully adjusted models, transient (hazard ratio 1.36, 95% confidence interval 1.29-1.46) or chronic (1.16, 1.04-1.32) hyperkalaemia patterns, but not current hyperkalaemia, were associated with major adverse cardiovascular events (MACE), compared with normokalaemia. Transient hyperkalaemia (1.43, 1.35-1.52) and current potassium values, but not chronic hyperkalaemia, were associated with the risk of death.Conclusions: Between 4% and 17% of patients with CKD G3-5 develop chronic hyperkalaemia. In general, hyperkalaemia predicted MACE and death; however, the lack of effect of current potassium on MACE when adjusted for the previous pattern, and the stronger effects on death than on MACE, lead us to question whether hyperkalaemia is causal in these relationships.
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