Reactions of Plasmodium falciparum Ferredoxin:NADP(+) Oxidoreductase with Redox Cycling Xenobiotics: A Mechanistic Study

Ferredoxin:NADP+ oxidoreductase from Plasmodium falciparum (PfFNR) catalyzes the NADPH-dependent reduction of ferredoxin (PfFd), which provides redox equivalents for the biosynthesis of isoprenoids and fatty acids in the apicoplast. Like other flavin-dependent electrontransferases, PfFNR is a potential source of free radicals of quinones and other redox cycling compounds. We report here a kinetic study of the reduction of quinones, nitroaromatic compounds and aromatic N-oxides by PfFNR. We show that all these groups of compounds are reduced in a single-electron pathway, their reactivity increasing with the increase in their single-electron reduction midpoint potential (E17). The reactivity of nitroaromatics is lower than that of quinones and aromatic N-oxides, which is in line with the differences in their electron self-exchange rate constants. Quinone reduction proceeds via a ping-pong mechanism. During the reoxidation of reduced FAD by quinones, the oxidation of FADH. to FAD is the possible rate-limiting step. The calculated electron transfer distances in the reaction of PfFNR with various electron acceptors are similar to those of Anabaena FNR, thus demonstrating their similar "intrinsic" reactivity. Ferredoxin stimulated quinone- and nitro-reductase reactions of PfFNR, evidently providing an additional reduction pathway via reduced PfFd. Based on the available data, PfFNR and possibly PfFd may play a central role in the reductive activation of quinones, nitroaromatics and aromatic N-oxides in P. falciparum, contributing to their antiplasmodial action

Fanconi-Anemia-Associated Mutations Destabilize RAD51 Filaments and Impair Replication Fork Protection

Fanconi anemia (FA) is a genetic disorder characterized by a defect in DNA interstrand crosslink (ICL) repair, chromosomal instability, and a predisposition to cancer. Recently, two RAD51 mutations were reported to cause an FA-like phenotype. Despite the tight association of FA/HR proteins with replication fork (RF) stabilization during normal replication, it remains unknown how FA-associated RAD51 mutations affect replication beyond ICL lesions. Here, we report that these mutations fail to protect nascent DNA from MRE11-mediated degradation during RF stalling in Xenopus laevis egg extracts. Reconstitution of DNA protection in\ua0vitro revealed that the defect arises directly due to altered RAD51 properties. Both mutations induce pronounced structural changes and RAD51 filament destabilization that is not rescued by prevention of ATP hydrolysis due to aberrant ATP binding. Our results further interconnect the FA pathway with DNA replication and provide mechanistic insight into the role of RAD51 in recombination-independent mechanisms of genome maintenance

Transport of a quantum degenerate heteronuclear Bose-Fermi mixture in a harmonic trap

We report on the transport of mixed quantum degenerate gases of bosonic 87Rb and fermionic 40K in a harmonic potential provided by a modified QUIC trap. The samples are transported over a distance of 6 mm to the geometric center of the anti-Helmholtz coils of the QUIC trap. This transport mechanism was implemented by a small modification of the QUIC trap and is free of losses and heating. It allows all experiments using QUIC traps to use the highly homogeneous magnetic fields that can be created in the center of a QUIC trap and improves the optical access to the atoms, e.g., for experiments with optical lattices. This mechanism may be cascaded to cover even larger distances for applications with quantum degenerate samples.Comment: 7 pages, 8 figure

Coherence length of an elongated condensate: a study by matter-wave interferometry

We measure the spatial correlation function of Bose-Einstein condensates in the cross-over region between phase-coherent and strongly phase-fluctuating condensates. We observe the continuous path from a gaussian-like shape to an exponential-like shape characteristic of one-dimensional phase-fluctuations. The width of the spatial correlation function as a function of the temperature shows that the condensate coherence length undergoes no sharp transition between these two regimes.Comment: 8 pages, 6 figure, submitted to EPJ

Nomenclature of the gadolinite supergroup

The newly defined gadolinite supergroup approved by the IMA CNMNC (vote 16-A) includes mineral species that have the general chemical formula A2MQ2T2O8\u20192 and belong to silicates, phosphates and arsenates. Each site is occupied by: A Ca, REE (Y and lanthanoids), actinoids, Pb, Mn2\ufe, Bi; M Fe, \u25a1 (vacancy), Mg, Mn, Zn, Cu, Al; Q B, Be, Li; T Si, P, As, B, Be, S; and\u2019 O, OH, F. The classification of the gadolinite supergroup is based on the occupancy of A, M, Q, T and\u2019 sites and application of the dominant-valency and dominant-constituent rules. The gadolinite supergroup is divided into two groups defined by prevailing charge occupancy at the T site Si4\ufe in gadolinite group and P5\ufe or As5\ufe in herderite group. The gadolinite group is divided into the gadolinite and datolite subgroups. The A site is dominantly occupied by divalent cations in the datolite subgroup and by trivalent cations in the gadolinite subgroup. Accordingly, the Q site is dominantly occupied by B3\ufe in the datolite subgroup and by Be2\ufe in the gadolinite subgroup. The herderite group is divided into two subgroups. The herderite subgroup is defined by the dominant divalent cation (usually Ca2\ufe) in the A site and Be2\ufe in the Q site, while the M site is vacant. The drugmanite subgroup is defined by the dominance of divalent cations (usually Pb2\ufe) in the A site, vacancy in the Q site and the occupation of the M site. Moreover, \u201cbakerite\u201d is discredited as mineral species because it does not meet the conditions of the dominant-constituent rule

Fluorarrojadite-(BaNa), BaNa4CaFe13Al(PO4)11(PO3OH)F2, a new member of the arrojadite group from Gemerská Poloma, Slovakia

The new mineral fluorarrojadite-(BaNa), ideally BaNa4CaFe13Al(PO4)11(PO3OH)F2 was found on the dump of of Elisabeth adit near Gemersk\ue1 Poloma, Slovakia. It occurs in hydrothermal quartz veins intersecting highly fractionated, topaz-zinnwaldite S-type leucogranite. Fluorarrojadite-(BaNa) is associated with fluorapatite, \u201cfluordickinsonite-(BaNa)\u201d, triplite, viitaniemiite and minor amounts of other minerals. It forms fine grained irregular aggregates up to 4 x 2 cm, which consists of individual anhedral grains up to 0.01 mm in size. It has a yellowish-brown to greenish-yellow colour, very pale yellow streak, a vitreous to greasy lustre. Mohs hardness is about 4\ubd to 5. The fracture is irregular and the tenacity is brittle. The measured density is 3.61(2) g\ub7cm-3 28 and calculated density is 3.650 g\ub7cm-3 29 . Fluorarrojadite-(BaNa) is biaxial (+) and nonpleochroic. The calculated refractive index based on empirical formula is 1.674. The empirical formula (based on 47 O and 3 (OH+F) apfu) is A1(Ba0.65K0.35)\u3a31.00 A2Na0.35 B1(Na0.54Fe0.46)\u3a31.00 B2Na0.54 Ca(Ca0.74Sr0.20Pb0.02Ba0.04)\u3a31.00Na2Na3 32 Na0.46M(Fe7.16Mn5.17Li0.37Mg0.12Sc0.08Zn0.06Ga0.02Ti0.02)\u3a313.00Al1.02P11O44PO3.46(OH)0.54 W 33 (F1.54OH0.46).Fluorarrojadite-(BaNa) is monoclinic, space group Cc, a = 16.563(1) \uc5, b = 10.0476(6) \uc5, c = 24.669(1) \uc5, \u3b2 = 105.452(4)\ub0, V = 3957.5(4) \uc53 and Z = 4. The seven strongest reflections in the powder X-ray diffraction pattern are [dobs in \uc5, (I), hkl]: 3.412, (21), 116; 3.224, (37), 206; 3.040, (100), 42-4; 2.8499, (22), 33-2; 2.7135, (56), 226; 2.5563, (33), 028 and 424; 2.5117, (23), 040. The new mineral is named according to the actual nomenclature scheme of arrojadite group minerals, which was approved by the CNMNC IMA. In fluorarrojadite-(BaNa) Fe2+ 40 is a dominant cation at the M site (so the root-name is arrojadite) and two suffixes are added to the root-name according to the dominant cation of the dominant valence state at the A1 (Ba2+) and B1 sites (Na+). A prefix fluor is added to the root-name as F- 42 is dominant over (OH)- 43 at the W site

How can ski resorts get smart? Transdisciplinary approaches to sustainable winter tourism in the European Alps

Climate change and the call for reduction of greenhouse gas emissions, the efficient use of (renewable) energy, and more resilient winter tourism regions, forces ski resorts across the European Alps to look for \u201csmart\u201d approaches to transition towards a sustainable, low-carbon economy. Drawing on the smart-city concept and considering the different historical developments of Alpine resorts, the Smart Altitude Decision-Making Toolkit was developed using a combination of an energy audit tool, a WebGIS, and collaborative and innovative living labs installed in Les Orres (France), Madonna di Campiglio (Italy), Krvavec (Slovenia), and Verbier (Switzerland). This step-by-step Decision-Making Toolkit enables ski resorts to get feedback on their energy demand, an overview of the locally available sources of renewable energy, and insights regarding their potential for improving their energy efficiency by low-carbon interventions. The Decision-Making Toolkit is suitable for knowledge transfer between stakeholders within living labs and moreover provides the flexibility for tailor-made low-carbon strategies adapting to the unique assets and situatedness of ski resorts

The zCOSMOS 20k Group Catalog

We present an optical group catalog between 0.1 < z < 1 based on 16,500 high-quality spectroscopic redshifts in the completed zCOSMOS-bright survey. The catalog published herein contains 1498 groups in total and 192 groups with more than five observed members. The catalog includes both group properties and the identification of the member galaxies. Based on mock catalogs, the completeness and purity of groups with three and more members should be both about 83% with respect to all groups that should have been detectable within the survey, and more than 75% of the groups should exhibit a one-to-one correspondence to the "real" groups. Particularly at high redshift, there are apparently more galaxies in groups in the COSMOS field than expected from mock catalogs. We detect clear evidence for the growth of cosmic structure over the last seven billion years in the sense that the fraction of galaxies that are found in groups (in volume-limited samples) increases significantly with cosmic time. In the second part of the paper, we develop a method for associating galaxies that only have photo-z to our spectroscopically identified groups. We show that this leads to improved definition of group centers, improved identification of the most massive galaxies in the groups, and improved identification of central and satellite galaxies, where we define the former to be galaxies at the minimum of the gravitational potential wells. Subsamples of centrals and satellites in the groups can be defined with purities up to 80%, while a straight binary classification of all group and non-group galaxies into centrals and satellites achieves purities of 85% and 75%, respectively, for the spectroscopic sample.Comment: 26 pages, 21 figures, published in ApJ (along with machine-readable tables