Paleo- to Mesoproterozoic sedimentary rocks in the southern margin of the North China Craton (NCC) are represented by the Ruyang and Luoyu groups. We studied the sedimentary rocks from the Yunmengshan and Beidajian formations of the Ruyang Group and the Cuizhuang and Sanjiaotang formations of the Luoyu Group. Detrital zircon grains from these formations have U–Pb age populations of 3.64–3.31 Ga, 2.96–2.86 Ga, 2.72–2.59 Ga, 2.56–2.47 Ga, 2.45–2.0 Ga, 1.99–1.85 Ga and 1.84–1.65 Ga. The geochemical features of the sedimentary rocks suggest that some of the sediments were sourced from intermediate to felsic magmatic rocks. The age groups of the detrital zircon are roughly consistent with the tectono-thermal events in the southern margin of the NCC. The Hf isotopic compositions of detrital zircon from the sedimentary rocks in Ruyang and Luoyu groups suggest that significant crustal growth and reworking of the NCC took place during the Neoarchean and early- to mid-Paleoproterozoic, while crustal reworking at the Paleoarchean and late-Paleoproterozoic, and crustal growth at the Mesoarchean. We suggest the depositional times of the Ruyang Group and Luoyu Group are constrained to no older than 1.75–1.7 Ga and 1.7–1.65 Ga, respectively. Formation of late-Paleoproterozoic basins related to the strike slip and extrusion tectonics that cross-cut the NCC during the late Paleoproterozoic (<1.75 Ga), and the late Paleoproterozoic sedimentation once isochronous developed in the southern margin of the NCC through the Taihang region of the interior NCC and linked the Yanshan–Liaoxi regions of the northern NCC.
When modern-style plate tectonics started and operated on a specific old craton has been a hot topic involving the early Earth's evolution. In order to address this issue on the evolution of the Neoarchean North China Craton (NCC), we investigated a newly identified successive magmatic rock suite of tonalite-trondhjemite-granodiorite (TTG)-sanukitoid in the Datong-Huai’an Complex. Geochemically, TTG gneisses in the Datong-Huai’an Complex can be divided into high-pressure (HP) and low-pressure (LP) TTG rocks. The HP TTGs are characterized by steep rare earth element (REE) patterns, obvious negative Nb, Ta and Ti anomalies and positive δEu anomalies, high Sr/Y, Nb/Ta and (La/Yb)N ratios, and positive Hf (t) (+2.1 to +8.7) and δ18O values (Ave 5.5‰ to 6.0‰). Their protolith is interpreted as the consequence of partial melting of a subducted oceanic slab with garnet and minor rutile as residual phases. The LP TTGs feature flat REE patterns, slightly negative Nb, Ta and Ti anomalies and negative δEu anomalies, low Sr/Y, Nb/Ta and (La/Yb)N ratios, positive Hf (t) (+3.4 to +5.9) and high δ18O values (Ave 5.9‰ to 6.1‰). They may have been generated by partial melting of mafic lower crust with residual plagioclase and amphibolite in the source. The sanukitoid rocks show high MgO, Cr and Ni concentrations but relatively low (La/Yb)N values, positive ɛHf (t) values (+1.5 to +5.4), and higher δ18O values (Ave 1.9‰ to 8.7‰), suggesting that they were originated from partial melting of mantle peridotite previously modified by slab-derived or sediment-derived melts. Zircon U–Pb dating results reveal that the HP TTGs formed at ~2538 Ma and ~2479–2441 Ma, whereas the LP TTGs and sanukitoids formed at ~2518 Ma and ~2517–2485 Ma, respectively. Combining rock assemblages, geochemical features and geological data, we propose that this long-lived magmatism can be divided into three stages of ~2.55-2.52 Ga, ~2.52-2.48 Ga and ~2.48-2.44 Ga. The Datong-Huai’an Complex may have developed along an active continental margin and depicts modern-style plate tectonics with continuous steep subduction, slab rollback and back-arc extension in the late Neoarchean.
Targeting ferroptosis, a unique cell death modality triggered by unrestricted lipid peroxidation, in cancer therapy is hindered by our incomplete understanding of ferroptosis mechanisms under specific cancer genetic contexts. KEAP1 (kelch-like ECH associated protein 1) is frequently mutated or inactivated in lung cancers, and KEAP1 mutant lung cancers are refractory to most therapies, including radiotherapy. In this study, we identify ferroptosis suppressor protein 1 (FSP1, also known as AIFM2) as a transcriptional target of nuclear factor erythroid 2-related factor 2 (NRF2) and reveal that the ubiquinone (CoQ)-FSP1 axis mediates ferroptosis- and radiation- resistance in KEAP1 deficient lung cancer cells. We further show that pharmacological inhibition of the CoQ-FSP1 axis sensitizes KEAP1 deficient lung cancer cells or patient-derived xenograft tumors to radiation through inducing ferroptosis. Together, our study identifies CoQ-FSP1 as a key downstream effector of KEAP1-NRF2 pathway and as a potential therapeutic target for treating KEAP1 mutant lung cancers.
The characteristics and evolution of a continental margin is of key importance in constructing the tectonic framework of a plate boundary. In the eastern North China Block (NCB), there is still controversy regarding the tectonic attribution and types of its continental margin during Paleozoic times, which yielded an understanding of convergence between the NCB and South China Block. In this study, we integrated the previous stratigraphic and sedimentologic results in the NCB to reconstruct the tectono‐paleogeographic evolution of its continental margin. The sedimentary records from Paleozoic to Early Mesozoic times in the eastern and southeastern margin of the NCB can be divided into 3 tectono‐stratigraphic sequences. The Early Paleozoic (Cambrian–Ordovician) sediments that are widespread in the eastern NCB reveal the well‐preserved drifting passive margin successions that consist of enormous thicknesses of limestone and dolomite. During the Late Carboniferous to Early Permian, the eastern NCB was dominated by clastic rocks interbedded with limestones, which implies a convergent passive margin. The Late Permian to Middle Triassic fluvial‐lacustrine units in the eastern NCB have developed in a syn‐collisional foreland basin. We emphasize that the Early Paleozoic passive margin of the eastern NCB directly converted to a convergent platform during the Late Paleozoic, which is consistent with a southeastward subduction rather than a transition to an active continental margin with a northwestward indentation. We suggest that the 3 tectono‐stratigraphic sequences are related to the opening and closure of the Proto‐ and Paleo‐Tethys Ocean in the eastern segment of the northern margin of Gondwana. Moreover, the transition of marine to terrestrial environments is associated with a collisional model about an orocline in East Asia.
Identifying the processes responsible for the generation and evolution of the Archean continental crust is crucial for understanding the tectonic regimes present on early Earth. A major episode of continental growth during the early Neoarchean has been identified in many cratons worldwide. Indeed, early Neoarchean magmatism has been recognized in several terranes within the North China Craton over the past decade, although the geodynamic regime in which such activity occurred remains highly debated. Here, we focus on newly recognized early Neoarchean mylonitic trondhjemite and granodiorite from the southern Jilin terrane, China, to address this knowledge gap. Zircon U-Pb geochronology reveals that these granitoids formed at ca. 2.7 Ga. They display adakitic geochemical characteristics, such as high Sr/Y and LaN/YbN ratios. Their low MgO, Cr, and Ni contents, along with low δ18O values (4.19‰−5.39‰) and positive εHf(t) (0.7−6.5) and εNd(t) (2.0−2.6) values, indicate that they originated from thickened juvenile lower continental crust. Thermodynamic modeling further constrains the ca. 2.7 Ga granitoids to have been generated from partial melting driven by amphibole breakdown under granulite-facies P-T conditions of 10−15 kbar and 800−900 °C, with garnet and amphibole as the major residual minerals. Combined with previous studies, we suggest that the North China Craton underwent significant crustal growth during the early Neoarchean, which was likely attributed to the synergistic effects of waning mantle plume activity and the coeval onset of plate tectonics.
Abstract In worldwide orogenic belts, crustal-scale ductile shear zones are important tectonic channels along which the orogenic root (i.e., high-grade metamorphic lower-crustal rocks) commonly experienced a relatively quick exhumation or uplift process. However, their tectonic nature and geodynamic processes are poorly constrained. In the Trans–North China orogen, the crustal-scale Zhujiafang ductile shear zone represents a major tectonic boundary separating the upper and lower crusts of the orogen. Its tectonic nature, structural features, and timing provide vital information into understanding this issue. Detailed field observations showed that the Zhujiafang ductile shear zone experienced polyphase deformation. Variable macro- and microscopic kinematic indicators are extensively preserved in the highly sheared tonalite-trondhjemite-granodiorite (TTG) and supracrustal rock assemblages and indicate an obvious dextral strike-slip and dip-slip sense of shear. Electron backscattered diffraction (EBSD) was utilized to further determine the crystallographic preferred orientation (CPO) of typical rock-forming minerals, including hornblende, quartz, and feldspar. EBSD results indicate that the hornblendes are characterized by (100) <001> and (110) <001> slip systems, whereas quartz grains are dominated by prism <a> and prism <c> slip systems, suggesting an approximate shear condition of 650–700 °C. This result is consistent with traditional thermobarometry pressure-temperature calculations implemented on the same mineral assemblages. Combined with previously reported metamorphic data in the Trans–North China orogen, we suggest that the Zhujiafang supracrustal rocks were initially buried down to ∼30 km depth, where high differential stress triggered the large-scale ductile shear between the upper and lower crusts. The high-grade lower-crustal rocks were consequently exhumed upwards along the shear zone, synchronous with extensive isothermal decompression metamorphism. The timing of peak collision-related crustal thickening was further constrained by the ca. 1930 Ma metamorphic zircon ages, whereas a subsequent exhumation event was manifested by ca. 1860 Ma syntectonic granitic veins and the available Ar-Ar ages of the region. The Zhujiafang ductile shear zone thus essentially record an integrated geodynamic process of initial collision, crustal thickening, and exhumation involved in formation of the Trans–North China orogen at 1.9–1.8 Ga.
Phenolic acids are lignin-derived fermentation inhibitors formed during many pretreatment processes of lignocellulosic biomass. In this study, vanillic, p-hydroxybenzoic, and syringic acids were selected as the model compounds of phenolic acids, and the effect of short-term adaptation strategies on the tolerance of S. cerevisiae to phenolic acids was investigated. The mechanism of phenolic acids tolerance in the adapted yeast strains was studied at the morphological and physiological levels.The multiple phenolic acids exerted the synergistic inhibitory effect on the yeast cell growth. In particular, a significant interaction between vanillic and hydroxybenzoic acids was found. The optimal short-term adaptation strategies could efficiently improve the growth and fermentation performance of the yeast strain not only in the synthetic media with phenolic acids, but also in the simultaneous saccharification and ethanol fermentation of corncob residue. Morphological analysis showed that phenolic acids caused the parental strain to generate many cytoplasmic membrane invaginations with crack at the top of these sites and some mitochondria gathered around. The adapted strain presented the thicker cell wall and membrane and smaller cell size than those of the parental strain. In particular, the cytoplasmic membrane generated many little protrusions with regular shape. The cytoplasmic membrane integrity was analyzed by testing the relative electrical conductivity, leakage of intracellular substance, and permeation of fluorescent probe. The results indicated that the short-term adaptation improved the membrane integrity of yeast cell.The inhibition mechanism of phenolic acid might be attributed to the combined effect of the cytoplasmic membrane damage and the intracellular acidification. The short-term adaptation strategy with varied stressors levels and adaptive processes accelerated the stress response of yeast cell structure to tolerate phenolic acids. This strategy will contribute to the development of robust microbials for biofuel production from lignocellulosic biomass.
The let-7 family of miRNAs has been shown to be crucial in many aspects of biology, from the regulation of developmental timing to cancer. The available methods to regulate this family of miRNAs have so far been mostly genetic and therefore not easily performed experimentally. Here, we describe a small molecule screen designed to identify regulators of let-7 targets in human cells. In particular, we focused our efforts on the identification of small molecules that could suppress let-7 targets, as these could serve to potentially intercede in tumors driven by loss of let-7 activity. After screening through roughly 36,000 compounds, we identified a class of phosphodiesterase inhibitors that suppress let-7 targets. These compounds stimulate cAMP levels and raise mature let-7 levels to suppress let-7 target genes in multiple cancer cell lines such as HMGA2 and MYC. As a result, these compounds also show growth inhibitory activity on cancer cells.
The Dabie–Sulu orogen is located in the eastern segment of the Central China Orogen between the North China Block (NCB) and the South China Block (SCB). The complex processes of break‐up and assemblage among the continental blocks of East Asia caused them to undergo multiple‐stage continental collisions. It is extremely important for the final kinematics and dynamics of convergence and collision among continental blocks to explore the exhumation mechanism of the HP (high pressure)‐UHP (ultra‐high pressure) metamorphic rocks. Therefore, this paper focuses on the final collisional process and tries to find a reasonable exhumation mechanism of the HP–UHP rocks. On the basis of the structural geology, petrology, seismic tomography, palaeomagnetism, and mathematical calculation, we propose a south‐eastward subduction of the NCB under the SCB in the Indosinian, and the Sulu Orogen actually became an orocline. This was caused by continuous south‐eastward subduction and the subsequent westward‐retreating delamination of the NCB slab. Coevally, it produced a two‐stage exhumation process, a vertical extrusion during the first stage (240–220 Ma) and an eastward extrusion controlled by an oroclinal contraction at the second stage (220–200 Ma).
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