The Arabidopsis thaliana checkpoint kinase WEE1 protects against premature vascular differentiation during replication stress

A sessile lifestyle forces plants to respond promptly to factors that affect their genomic integrity. Therefore, plants have developed checkpoint mechanisms to arrest cell cycle progression upon the occurrence of DNA stress, allowing the DNA to be repaired before onset of division. Previously, the WEE1 kinase had been demonstrated to be essential for delaying progression through the cell cycle in the presence of replication-inhibitory drugs, such as hydroxyurea. To understand the severe growth arrest of WEE1-deficient plants treated with hydroxyurea, a transcriptomics analysis was performed, indicating prolonged S-phase duration. A role for WEE1 during S phase was substantiated by its specific accumulation in replicating nuclei that suffered from DNA stress. Besides an extended replication phase, WEE1 knockout plants accumulated dead cells that were associated with premature vascular differentiation. Correspondingly, plants without functional WEE1 ectopically expressed the vascular differentiation marker VND7, and their vascular development was aberrant. We conclude that the growth arrest of WEE1-deficient plants is due to an extended cell cycle duration in combination with a premature onset of vascular cell differentiation. The latter implies that the plant WEE1 kinase acquired an indirect developmental function that is important for meristem maintenance upon replication stress

Toward an ecological aesthetics: music as emergence

In this article we intend to suggest some ecological based principles to support the possibility of develop an ecological aesthetics. We consider that an ecological aesthetics is founded in concepts as “direct perception”, “acquisition of affordances and invariants”, “embodied embedded perception” and so on. Here we will purpose that can be possible explain especially soundscape music perception in terms of direct perception, working with perception of first hand (in a Gibsonian sense). We will present notions as embedded sound, detection of sonic affordances and invariants, and at the end we purpose an experience with perception/action paradigm to make soundscape music as emergence of a self-organized system

Boundary conformal fields and Tomita--Takesaki theory

Motivated by formal similarities between the continuum limit of the Ising model and the Unruh effect, this paper connects the notion of an Ishibashi state in boundary conformal field theory with the Tomita--Takesaki theory for operator algebras. A geometrical approach to the definition of Ishibashi states is presented, and it is shownthat, when normalisable the Ishibashi states are cyclic separating states, justifying the operator state correspondence. When the states are not normalisable Tomita--Takesaki theory offers an alternative approach based on left Hilbert algebras, opening the way to extensions of our construction and the state-operator correspondence.Comment: plain Te

Mixing of magmatic-hydrothermal and metamorphic fluids and the origin of peribatholitic Sn vein-type deposits in Rwanda

The fluid sources of granite-related Sn-quartz vein deposits are commonly obscured by fluid mixing or fluid-rock interactions. As a result, fluid inclusions, minerals and isotopes in these veins indicate an intermediate composition between magmatic and metamorphic, but the degree of mixing between these endmembers is currently unquantified. This study presents a novel quantitative approach to assess the degree of mixing between magmatic-hydrothermal and external metamorphic fluids in the formation of peribatholitic Sn-quartz veins. In particular, fluid mixing in the Sn-mineralized Rwamagana-Musha-Ntunga pegmatite-quartz vein field in East Rwanda has been evaluated by the following four methods: quartz stable isotopes, muscovite geochemistry, fluid inclusion microthermometry and LA-ICP-MS, and geochemical modelling. The quartz stable isotope data (δ18O: +13.1 to +15.8 ‰ V-SMOW; δD: −27.6 to –59.7 ‰ V-SMOW) cannot uniquely differentiate between a metamorphic fluid origin or an initial magmatic hydrothermal fluid origin with subsequent metamorphic fluid mixing or host-rock interaction. However, granitophile element concentrations in magmatic muscovite from pegmatites and hydrothermal muscovite from associated Sn-quartz veins are equally high, indicating a close genetic link (Rb: 530 – 8740 ppm, Li: 110 – 1990 ppm, Sn: 87 – 810 ppm, Cs: 62 – 420 ppm). Primary H2O-CO2-N2-NaCl medium saline magmatic fluid inclusions in quartz of pegmatites (∼12.7 wt% NaCleq) and H2O-CO2-(N2)-NaCl low saline fluid inclusions in barren metamorphic quartz veins (∼4.9 wt% NaCleq) were analyzed by LA-ICP-MS. These results show an enrichment in Li, Rb, Sn and Cs for the magmatic fluid, while the metamorphic fluid is characterized by low granitophile element concentrations and high Sr and Ba contents. The expected Rb-Cs and Rb-Sn signature of the Sn-quartz vein muscovite was modelled using the measured fluid endmember compositions, confirming mixing between magmatic and metamorphic fluids in the formation of the veins. The quantification suggests that the hydrothermal Sn-quartz vein fluid contains 5 – 80 % of an external metamorphic fluid component

Ferulic acid-4-O-sulfate rather than ferulic acid relaxes arteries and lowers blood pressure in mice

Consumption of foods rich in ferulic acid (FA) such as wholegrain cereals, or FA precursors such as chlorogenic acids in coffee, is inversely correlated with risk of cardiovascular disease and type 2 diabetes. As a result of digestion and phase II metabolism in the gut and liver, FA is converted predominantly into ferulic acid-4-O-sulfate (FA-sul), an abundant plasma metabolite. Although FA-sul may be the main metabolite, very little has been reported regarding its bioactivities. We have therefore compared the ex vivo vasorelaxing effect of FA and FA-sul (10−7 - 3.10−5 M) on isolated mouse arteries mounted in tissue myographs. FA-sul, but not FA, elicited a concentration-dependent vasorelaxation of saphenous and femoral arteries and aortae. The FA-sul mediated vasorelaxation was blunted by 1H- [1, 2, 4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), a soluble guanylate cyclase (sGC) inhibitor. The role of sGC was confirmed in femoral arteries isolated from sGCα1(−/−) knockout mice. Furthermore, 4-aminopyridine, a specific inhibitor of voltage-dependent potassium channels, significantly decreased FA-sul mediated effects. In anesthetized mice, intravenous injection of FA-sul decreased mean arterial pressure, whereas FA had no effect, confirming the results obtained ex vivo. FA-sul is probably one of the major metabolites accounting for the blood pressure-lowering effects associated with FA consumption