ALBERT

Description: 〈p〉PGAM5, a mitochondrial protein phosphatase that is genetically and biochemically linked to PINK1, facilitates mitochondrial division by dephosphorylating the mitochondrial fission factor Drp1. At the onset of mitophagy, PGAM5 is cleaved by PARL, a rhomboid protease that degrades PINK1 in healthy cells, and the cleaved form facilitates the engulfment of damaged mitochondria by autophagosomes by dephosphorylating the mitophagy receptor FUNDC1. Here, we show that the function and localization of PGAM5 are regulated by syntaxin 17 (Stx17), a mitochondria-associated membrane/mitochondria protein implicated in mitochondrial dynamics in fed cells and autophagy in starved cells. In healthy cells, loss of Stx17 causes PGAM5 aggregation within mitochondria and thereby failure of the dephosphorylation of Drp1, leading to mitochondrial elongation. In Parkin-mediated mitophagy, Stx17 is prerequisite for PGAM5 to interact with FUNDC1. Our results reveal that the Stx17-PGAM5 axis plays pivotal roles in mitochondrial division and PINK1/Parkin-mediated mitophagy.〈/p〉

Description: A master sex-determining gene, the Y chromosome-linked anti-Müllerian hormone ( amhy ) gene, has been described in two New World atheriniform species but little is known on the distribution, evolution, and function(s) of this gene in other Atheriniformes. Interestingly, amhy has been found to coexist with temperature-dependent sex determination (TSD), providing a unique opportunity to explore the interplay between genotypic and environmental sex determination. In this study, the search for an amhy homolog was extended to an Old World atheriniform, the cobaltcap silverside Hypoatherina tsurugae (Atherinidae). The full sequences, including the coding and noncoding regions, of the autosomal amh ( amha ) and a putative amhy were obtained. The deduced Amha and Amhy proteins comprised 511 and 340 amino acids (aa), respectively. PCR analysis with genomic DNA from wild adults and from laboratory-reared juveniles revealed a high, but not complete association of ~95% between amhy and maleness. The spatiotemporal expression of amhy and amha during gonadal sex differentiation was analyzed by qRT-PCR and in situ hybridization (ISH). amhy transcription (in amhy -positive larvae) started before and peaked during histological differentiation of the gonads whereas amha was negligible during the same period in both genotypes. These results demonstrate that the amhy , although with some structural differences in relation to the amhy of some New World atheriniforms, is strongly associated with maleness and probably important for testicular development in this Old World atheriniform. Thus, amhy is a candidate sex determination gene in cobaltcap silverside and it will be key to scrutinize the mechanism of sex determination in this species.

Description: Author(s): T. Nomoto, K. Hattori, and H. Ikeda Motivated by a growing interest in multiorbital superconductors with spin-orbit interactions, we perform the group-theoretical classification of various unconventional superconductivity emerging in symmorphic O ,   D 4 , and D 6 space groups. The generalized Cooper pairs, which we here call “multipole” su… [Phys. Rev. B 94, 174513] Published Tue Nov 22, 2016

Description: We explored a method to reconstruct the distribution function of the Galactic thick disc within the action space where nearby thick-disc stars are distributed. By applying this method to 127 chemically selected thick-disc stars in the solar neighbourhood, we found that the vertical velocity dispersion that corresponds to the reconstructed distribution function declines approximately as exp (– R / R s ) at 4.5 kpc R 9.5 kpc, with R s  = 8.3 ± 1.1(rand.) ± 1.6(sys.) kpc. Also, we found that the vertical velocity dispersion z of our local thick-disc stars shows only weak dependence on radial and azimuthal velocities ( v R , v ). We discuss possible implications of these results on the global structure of the Milky Way thick disc.

Description: The dynamics of stellar streams in rotating barred potentials is explained for the first time. Naturally, neighbouring stream stars reach pericentre at slightly different times. In the presence of a rotating bar, these neighbouring stream stars experience different bar orientations during pericentric passage and hence each star receives a different torque from the bar. These differing torques reshape the angular momentum and energy distribution of stars in the stream, which in turn changes the growth rate of the stream. For a progenitor orbiting in the same sense as the bar's rotation and satisfying a resonance condition, the resultant stream can be substantially shorter or longer than expected, depending on whether the pericentric passages of the progenitor occur along the bar's minor or major axis, respectively. We present a full discussion of this phenomenon focusing mainly on streams confined to the Galactic plane. In stark contrast with the evolution in static potentials, which give rise to streams that grow steadily in time, rotating barred potentials can produce dynamically old, short streams. This challenges the traditional viewpoint that the inner halo necessarily consists of well phase-mixed material whilst the tidally disrupted structures in the outer halo are more spatially coherent. We argue that this mechanism may play an important role in explaining the mysteriously short Ophiuchus stream that was recently discovered near the bulge region of the Milky Way.

Description: 〈span〉The organic-rich Macasty shale in the Gulf of St. Lawrence was deposited in the Late Ordovician during the Taconic orogeny. The orogeny involved explosive volcanism and thrusting of allochthonous rocks in the eastern margin of North America. Neodymium isotope compositions of the shale show that the provenance is predominantly Grenvillian granite–gneissic rocks, which were widely exposed north of the basin, with little contribution from Taconic igneous rocks. The bulk composition and the presence of detrital kaolinite suggest that the Grenvillian source rocks underwent intense weathering before erosion. Fine-grained detritus was deposited in the Anticosti Basin, where abundant organic activity kept the sediment–water interface under anoxic conditions. This proposed interpretation is supported by the enrichment of redox-sensitive elements, such as As, V, and U, and by high δ〈sup〉34〈/sup〉S for pyrite. Calcite cement formed in the pore space of sediments during the diagenesis at temperatures below 60 °C. The low-temperature diagenetic conditions are consistent with the preservation of abundant organic matter in the shale.〈/span〉

Description: In this study we examined Meso- to Neoarchean granitoids from the North Caribou Terrane within the Western Superior Province, Canada. Petrology, whole-rock geochemistry, zircon and titanite geochronology, and zircon trace element concentrations were analyzed. U–Pb ages from zircon and titanite are between 2·62 and 3·13 Ga. Although most of the granitoids in this study appear to record a complex magmatic history, about a third contain features that we interpret to be a result of hydrothermal alteration. Notable traits in rocks that contain altered zircons include K-feldspar overgrowths on plagioclase and compositional zoning in titanite. The altered zircon material itself occurs as CL-bright resorption shadows showing distinct chemical changes, including lower Th/U values and elevated LREE concentrations. The isotopic ages of the rims on the altered zircons (2835 Ma, 2760–2678 Ma) are similar to coexisting U–Pb titanite ages and regional U–Pb titanite and zircon ages. We propose that during the hydrothermal event, the affected areas of zircon re-equilibrated with fluid, which promoted Pb loss, resetting the isotopic clock. These results suggest that zircon rims might be useful for dating hydrothermal fluid flow episodes in addition to magmatic events and that a multi-element approach is useful for distinguishing ages that are magmatic from those that have been isotopically disturbed owing to alteration.

Description: The Athabasca Basin hosts world class uranium deposits, such as the McArthur River deposit. This paper presents the occurrence of aluminum phosphate-sulfate (APS) minerals in the metasedimentary rocks along the P2 fault, the main ore-hosting fault of the McArthur River deposit. It compares the APS minerals along the P2 fault with those outside the fault, examined in this study, and those from other deposits of the Athabasca Basin and from other Paleo- to Mesoproterozoic basins worldwide. APS minerals are common along the P2 fault but rare outside of the P2 fault zone in the basement and along the unconformity between the Athabasca sandstones and the basement. The APS minerals along the P2 fault occur with sudoite (± illite, magnesiofoitite) and are zoned with Sr-, Ca-, and S-rich cores (solid solution between svanbergite, crandallite, and goyazite) and LREE- and P-rich rims (close to florencite composition). APS minerals in the Bleached Zone (altered rocks along the unconformity consisting predominantly of kaolin and illite) are Sr-, Ca-, and S-rich (high svanbergite component) and occur with kaolin. APS minerals in the Red-Green Zone (mingled red hematitic and green chloritic basement rocks below the Bleached Zone) occur with sudoite and clinochlore. They contain relict cores of LREE- and As-rich arsenoflorencite-(Ce) and rims of svanbergite-goyazite-crandallite solid solution. The occurrence of svanbergite-crandallite-goyazite along the unconformity suggests their formation by relatively oxidizing fluids during diagenesis of the overlying sandstones. The relict cores of arsenoflorencite-(Ce) in the Red-Green Zone are interpreted to be the product of paleo-weathering before the deposition of the Athabasca sandstones. Florencitic APS minerals are found along the entire studied strike length (7 km) of the P2 fault, including the ore zone and non-mineralized areas, but are absent outside the fault zone. The florencitic APS minerals contain low SO 4 2– in the ore zone, suggesting relatively reducing conditions during their crystallization. Zoned APS minerals (with svanbergitic cores and florencitic rims) proximal to ore contain elevated U (up to 16 ppm). These features suggest that diagenetic, oxidizing, and uranium-bearing fluids traveled along the P2 fault and became relatively reduced, especially within the ore zone. It also suggests florencitic APS minerals are contemporaneous with uranium mineralization. The restricted occurrence of florencitic APS mineral along the P2 fault in the basement suggests their use in identifying fertile basement structures associated with uranium mineralization.

Description: The Central Asian Orogenic Belt (CAOB) hosts a number of porphyry Cu deposits, all associated with calc-alkaline granitic rocks and ranging in size from giant to small. Major- and trace-element compositions of whole rocks and zircons grains were measured from 13 ore-bearing intrusions in nine porphyry Cu deposits (with 0.6 to 12 Mt Cu), including Bozshakol, Nurkazghan, Kounrad, Borly, Aktogai, and Koksai in Kazakhstan, Baogutu, and Tuwu-Yandong in China, and Erdenet in Mongolia. All zircon grains show high Ce 4+ /Ce 3+ ratios, ranging from 29 to 592. Higher Ce 4+ /Ce 3+ ratios are recorded at a given crystallization temperature from deposits with larger Cu tonnages. Large (〉4 Mt Cu) and intermediate (1.5–4 Mt Cu) size porphyry Cu deposits are associated with granitic intrusions that have zircons with Ce 4+ /Ce 3+ ratios greater than 120. There is also a clear relationship between calculated log $$(f{\mathrm{O}}_{2})$$ values and the size of deposits, with NNO + 2 values separating large and intermediate porphyry deposits from small deposits. The data of zircon Ce 4+ /Ce 3+ ratios and associated oxygen fugacity values in magma from ore-bearing intrusions indicate that more oxidized magmas are associated with the formation of larger porphyry Cu deposits. Such a conclusion may potentially be used in regional exploration for porphyry Cu deposits in the CAOB.