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SUMMARY: Rosa roxburghii and Rosa sterilis, two species belonging to the Rosaceae family, are widespread in the southwest of China. These species have gained recognition for their remarkable abundance of ascorbate in their fresh fruits, making them an ideal vitamin C resource. In this study, we generated two high‐quality chromosome‐scale genome assemblies for R. roxburghii and R. sterilis, with genome sizes of 504 and 981.2 Mb, respectively. Notably, we present a haplotype‐resolved, chromosome‐scale assembly for diploid R. sterilis. Our results indicated that R. sterilis originated from the hybridization of R. roxburghii and R. longicuspis. Genome analysis revealed the absence of recent whole‐genome duplications in both species and identified a series of duplicated genes that possibly contributing to the accumulation of flavonoids. We identified two genes in the ascorbate synthesis pathway, GGP and GalLDH, that show signs of positive selection, along with high expression levels of GDP‐d‐mannose 3′, 5′‐epimerase (GME) and GDP‐l‐galactose phosphorylase (GGP) during fruit development. Furthermore, through co‐expression network analysis, we identified key hub genes (MYB5 and bZIP) that likely regulate genes in the ascorbate synthesis pathway, promoting ascorbate biosynthesis. Additionally, we observed the expansion of terpene synthase genes in these two species and tissue expression patterns, suggesting their involvement in terpenoid biosynthesis. Our research provides valuable insights into genome evolution and the molecular basis of the high concentration of ascorbate in these two Rosa species. [ABSTRACT FROM AUTHOR]

Background: Circular RNAs (circRNAs) play a significant role in the initiation and progression of various cancers, including hepatocellular carcinoma (HCC). Circular syntaxin 6 (circSTX6, also known as hsa_circ_0007905) has been identified as a microRNA (miRNA) sponge in pancreatic adenocarcinoma. However, its full range of functions in terms of protein scaffold and translation remain largely unexplored in the context of HCC. Methods: The expression of circSTX6 and its encoded protein was examined in HCC tumour tissues. N6‐methyladenosine (m6A) on circSTX6 was verified and quantified by methylated RNA immunoprecipitation (Me‐RIP), RIP and dual luciferase reporter assays. The biological functions of circSTX6 and its encoded protein in HCC were clarified by in vitro and in vivo experiments. Mechanistically, the interaction between circSTX6 and heterogeneous nuclear ribonucleoprotein D (HNRNPD) was investigated by RNA pull‐down, RIP and fluorescence in situ hybridization (FISH)/IF. The regulatory effects of circSTX6 and HNRNPD on activating transcription factor 3 (ATF3) mRNA were determined by mRNA stability and RIP assays. Furthermore, the presence of circSTX6‐encoded protein was verified by mass spectrometry. Results: CircSTX6 and its encoded 144 amino acid polypeptide, circSTX6‐144aa, were highly expressed in HCC tumour tissues and served as independent risk factors for overall survival in HCC patients. The expression of circSTX6 was regulated by METTL14 in an m6A‐dependent manner. Functionally, circSTX6 accelerated HCC proliferation and tumourigenicity and reinforced tumour metastasis in vitro and in vivo. Mechanistically, circSTX6 acted as a sponge for HNRNPD protein, facilitating its binding to ATF3 mRNA, consequently promoting ATF3 mRNA decay. Meanwhile, circSTX6‐144aa promoted HCC proliferation, migration and invasion independent of circSTX6 itself. Conclusion: Collectively, our study reveals that m6A‐modified circSTX6 drives malignancy in HCC through the HNRNPD/ATF3 axis, while its encoded circSTX6‐144aa contributes to HCC progression independent of circSTX6. CirSTX6 and its encoded protein hold promise as potential biomarkers and therapeutic targets in HCC. [ABSTRACT FROM AUTHOR]

The movement of active dunes is tightly linked to climatic conditions (e.g., wind regime, temperature and precipitation) as well as human influence (e.g., grazing, dune fixation and greening). Dune migration rates can be studied to draw conclusions of changing wind conditions over time. The Gonghe Basin (GB), located on the north‐eastern Tibetan Plateau (TP), offers a good testing ground for these assumptions. The intramontane basin is highly influenced by two major wind regimes: the mid‐latitude Westerlies and the East Asian summer monsoon. To investigate environmental changes, this study combines optical remote sensing techniques with climatic datasets. High‐resolution satellite images of the last five decades, such as CORONA KH‐4B, are used to map dunes and calculate their respective migration rates. Further, height information was extracted as well. Climatic changes from the ERA‐5 reanalysis dataset and normalized difference vegetation index (NDVI) values were processed alongside. Relating the dunes' surface processes to climate model data shows an accordance between slowing migration, expanding vegetation and a decrease in sand drift potential. From 1968 to present time, an average dune migration rate of 7.3 m a−1 was extracted from the satellite images, with an overall reduction of −1.81 m a−1. The resultant drift potential (RDP) values for the GB are calculated to be below 10 m3 s−3 with a spatial decrease, following a direction from the NW to the SE, fitting well with a corresponding decrease in the migration rates. Our results indicate a good agreement between the development of aeolian landforms and the ERA‐5 climate reanalysis model data, even in a high‐altitude setting with complex topography, which is known to influence such datasets. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is one of the most common malignancies with poor prognosis, and novel treatment strategies are urgently needed. Mitochondria are key regulators of cellular homeostasis and potential targets for tumor therapy. Here, the role of mitochondrial translocator protein (TSPO) in the regulation of ferroptosis and antitumor immunity is investigated and the potential therapeutic implications for HCC are assessed. TSPO is highly expressed in HCC and associated with poor prognosis. Gain‐ and loss‐of‐function experiments present that TSPO promotes HCC cell growth, migration, and invasion in vitro and in vivo. In addition, TSPO inhibits ferroptosis in HCC cells via enhancing the Nrf2‐dependent antioxidant defense system. Mechanistically, TSPO directly interacts with P62 and interferes with autophagy, leading to the accumulation of P62. The P62 accumulation competes with KEAP1, preventing it from targeting Nrf2 for proteasomal degradation. Furthermore, TSPO promotes HCC immune escape by upregulating PD‐L1 expression through Nrf2‐mediated transcription. Notably, TSPO inhibitor PK11195 combines with anti‐PD‐1 antibody showing a synergistic anti‐tumor effect in a mouse model. Overall, the results demonstrated that mitochondrial TSPO promotes HCC progression by inhibiting ferroptosis and antitumor immunity. Targeting TSPO can be a promising new strategy for HCC treatment. [ABSTRACT FROM AUTHOR]

Meltwater Pulse 1A injection into the North Atlantic coincided with the Bølling warming event, despite climate model simulations indicating that the Meltwater Pulse 1A should have inevitably lead to an extreme cooling in the northern hemisphere. However, so far no cooling event has been found in paleoclimate records responding to Meltwater Pulse 1A. Here we reconstruct winter temperature based on sedimentary diatoms from Huguangyan Maar Lake in tropical China. The results show that winter temperature dropped by at least 6°C within ∼100 years at 14.8 ± 0.02 ka BP, coeval with the onset of Meltwater Pulse 1A, within dating uncertainty. We argue that Meltwater Pulse 1A weakened the Atlantic Meridional Overturning Circulation (AMOC), resulting in abrupt severe cooling in the Northern Hemisphere that caused a severe winter temperature drop in East Asia by strengthening the winter monsoon. We propose that extreme cooling in winter temperature triggered the Bølling warming by stopping the freshwater release from the ice‐sheet, triggering the AMOC to recover quickly and causing the Bølling event as an overshoot under gradual forcing. Plain Language Summary: It is generally accepted that large quantities of meltwater injected into the ocean is reducing Atlantic Meridional Overturning Circulation and will causes a significant cooling event in the Northern Hemisphere. However, it was not a cooling event that coincided with Meltwater pulse1A, the largest freshwater injection of the Late Quaternary, but the abrupt Bølling warming event. This paradox is still debated because so far no cooling event coinciding with Meltwater Pulse 1A has been found in paleoclimatic records. This is mainly due to the lack of suitable proxy and high‐resolution records in high northern latitude regions. Here, we establish the relationship between the diatoms contained in the sediment record and temperature to reconstruct the changes in temperature during the last deglacial from the high‐resolution record of a volcanic lake. We find that an extreme cooling event occurred at the onset of Meltwater Pulse 1A. We think that this extreme cooling triggered the abrupt warming event known as the Bølling warming event. Key Points: We provide evidence that winter temperature dropped by at least 6°C just before the Bølling warming event in southern ChinaWe argue that this extreme cooling event was caused by the Meltwater Pulse1A eventWe propose that this extreme cooling event triggered the Bølling warming by stopping freshwater release into the North Atlantic [ABSTRACT FROM AUTHOR]

Seasonal changes in wind regime have driven the formation and emergence of reversing dunes and crest reversal in the inland arid and coastal areas of Asia, but due to the strong prevailing winds, the reversing dunes or reversing crest can be flipped. Therefore, the transient reversing dunes or crest reversal will be ignored and unobserved. To investigate dune morphology and sedimentology concerning seasonal alternation of the wind regime, we reconstructed dune topographies using aerial drone photos and analyzed the grain‐size parameters and internal sedimentary structures of dunes. Morphological results show that wind‐blown sands from the lee side are transported and deposited on the upper stoss side because of the reversing winds. Then, the dune crestal area is flattened, surface sand compositions were reorganized from fining to coarsening at the dune crest. Combining these field surveys with numerical simulation results, we found that the internal sedimentary structures are composed of high‐angle cross‐strata and low‐angle bounding surfaces. The dip angles of the bounding surfaces gradually decrease from the bottom to the top because of the reversing wind erosion on the lee side. The increase in sand flux on the lee side plays a critical role in shaping the dip angle of the bounding surfaces due to the speed‐up effect. Plain Language Summary: Under the influence of the East Asian monsoon system, near‐surface wind strength and direction are characterized by strong northwest winds in spring and winter, and weak southeast winds in summer. The seasonal changes in wind regimes reshape the dune forms and reorganize the grain‐size characteristics and internal sedimentary structures of the dunes. After the influence of reversing wind, dune crestal areas are flattened, then dune crests are flipped, oriented in the opposite direction. The sands on the downwind side were transported and deposited on the upwind side by the reversing wind, causing the grain fining characteristics on the dune crest to change into coarsening characteristics. Moreover, field surveys show that internal layering structures in dune shift from a southeast dip in the lower part to a northwest dip in the upper part. It reveals that sand deposition on the downwind side caused by NW winds becomes sand deposition on the upwind side induced by SE winds. Numerical simulation results quantitatively illustrate that the internal sedimentary structures are composed of high‐angle cross‐strata and low‐angle bounding surfaces. The dip angles of the bounding surfaces gradually decrease from the bottom to the top because of the reversing wind erosion on the lee side. Key Points: Reversing winds produce reversing slip faces and rework sands on dune crestal areasHigh‐angle cross‐strata are truncated by low‐angle bounding surfaces in asymmetrical bidirectional wind regimesThe bounding surface angle decreases with height, which is caused by the reversing wind erosion due to the speed‐up effect [ABSTRACT FROM AUTHOR]

The potential interactions between aeolian and fluvial systems are critical in understanding environmental change. Whether aeolian products originated from the river depends on the river characteristics and wind regimes. In southern Tibet, aeolian sand dunes are widespread along the Yarlung River, and thus provide an ideal example to explore the relationships between large fluvial systems and aeolian products. Although previous studies postulated that those aeolian products were originated from the Yarlung River, few empirical data actually exist to support this idea. We analysed the spatial pattern, sand transportation directions, and granulometric characteristics of the sand dunes to evaluate the potential influence of the Yarlung River on the aeolian processes. Comparison of the dune field distribution against channel width and longitudinal profile of the Yarlung River shows that sand dunes are clustered at the wide and flat segments of the river. Analyses of >4,600 sand dune orientations using Google Earth imagery show that the dunes located at the southern and northern sides of the Yarlung River demonstrate opposite sand transportation directions that generally point against the river. This suggests that the sand grains probably originated from the river. Grain size distributions from dune samples show unimodal or unimodal‐like patterns. This means that each sand dune field was dominantly fed by a simple transportation process rather than by compound processes from smaller‐level fluvial systems, which in turn implies that the Yarlung River was the most possible candidate for the provenance of these aeolian deposits. This study provides new constraints to demonstrate that the Yarlung River provides both accommodation space and sorted fluvial sand for the aeolian sand dunes along the river. [ABSTRACT FROM AUTHOR]

The evolution of barchan‐to‐parabolic dunes can be driven by vegetation establishment, which may be linked to climate change and/or human activity. However, little is known of the impact of changes in wind strength on vegetation development and the resulting impacts on the evolution of dune morphology and sedimentological characteristics. To address this issue, we studied the morphology and grain‐size characteristics of barchan, barchan‐to‐parabolic and parabolic dunes in the Mu Us Desert in north China, which was combined with an analysis of changes in normalized difference vegetation index (NDVI) and climatic variables during 1982–2018. The results reveal a trend of increasing growing‐season NDVI which was related to a significant decrease in drift potential (DP). Therefore, we suggest that the initiation of dune transformation was caused by the reduced wind strength which favored the establishment and development of vegetation. To reveal the response of sedimentological reorganization during the processes of dune transformation, grain‐size characteristics along the longitudinal profile of the three different types of dunes were examined. The decreasing wind strength led to the transport of fine sands on the upper part of the windward face of the dunes, resulting in a progressive coarsening of the grain‐size distribution (GSD) and a reduction in dune height at the crest area. No distinct trend in sorting and mean grain‐size was observed on the windward slope of the barchan‐to‐parabolic dune, indicating that the sand in transit had little influence on the GSD. Conversely, progressive sorting and coarsening of the sand occurred towards the crest of the parabolic dune. This indicates that vegetation development limited the transport of sand from upwind of the dune, and affected a shift in the dune source material to the underlying source deposits, or to reworked pre‐existing aeolian deposits, and resulted in the trapping of sand in the crest area. © 2020 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]