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Arctic changes influence not only temperature and precipitation in the midlatitudes but also contribute to severe convection. This study investigates an extreme gale event that occurred on 30 April 2021 in East China and was forced by an Arctic potential vorticity (PV) anomaly intrusion. Temperature advection steered by storms contributed to the equatorward propagation of Arctic high PV, forming the Northeast China cold vortex (NCCV). At the upper levels, a PV southward intrusion guided the combination of the polar jet and the subtropical jet, providing strong vertical wind shear and downward momentum transportation to the event. The PV anomaly cooled the upper troposphere and the northern part of East China, whereas the lower levels over southern East China were dominated by local warm air, thus establishing strong instability and baroclinicity. In addition, the entrainment of Arctic dry air strengthened the surface pressure gradient by evaporation cooling. Capturing the above mechanism has the potential to improve convective weather forecasts under climate change. This study suggests that the more frequent NCCV-induced gale events in recent years are partly due to high-latitude waviness and storm activities, and this hypothesis needs to be investigated using more cases. [ABSTRACT FROM AUTHOR]

The cabbage white butterfly (Pieris rapae), a major agricultural pest, has become one of the most abundant and destructive butterflies in the world. It is widely distributed in a large variety of climates and terrains of China due to its strong adaptability. To gain insight into the population genetic characteristics of P. rapae in China, we resequenced the genome of 51 individuals from 19 areas throughout China. Using population genomics approaches, a dense variant map of P. rapae was observed, indicating a high level of polymorphism that could result in adaptation to a changing environment. The feature of the genetic structure suggested considerable genetic admixture in different geographical groups. Additionally, our analyses suggest that physical barriers may have played a more important role than geographic distance in driving genetic differentiation. Population history showed the effective population size of P. rapae was greatly affected by global temperature changes, with mild periods (i.e., temperatures warmer than those during glaciation but not excessively hot) leading to an increase in population size. Furthermore, by comparing populations from south and north China, we have identified selected genes related to sensing temperature, growth, neuromodulation and immune response, which may reveal the genetic basis of adaptation to different environments. Our study is the first to illustrate the genetic signatures of P. rapae in China at the population genomic level, providing fundamental knowledge of the genetic diversity and adaptation of P. rapae. [ABSTRACT FROM AUTHOR]

Recent research on knowledge hiding has focused on its interpersonal antecedents, such as co-worker relationships. However, few research has investigated the role of vertical relationships on reducing knowledge hiding behaviors. Extending this line of research, we examined the impacts of work-related (i.e., leader–member exchange, LMX) and non-work-related (i.e., supervisor–subordinate guanxi, SSG) supervisor–subordinate relationships on knowledge hiding. Drawing from social exchange and social cognitive theories, we proposed that both LMX and SSG negatively influence subordinates' knowledge hiding through psychological safety. With a three-wave time-lagged design and data collected from 223 employees in China, our results show that (a) both LMX and SSG are negatively related to knowledge hiding; (b) psychological safety fully mediates the impact of LMX on knowledge hiding, whereas it partially mediates the impact of SSG on knowledge hiding. Theoretical and practical implications, research limitations, and promising avenues for future research are discussed. [ABSTRACT FROM AUTHOR]

Reaumuria trigyna, a Tamaricaceae archaic recretohalophyte, is an important feral forage plant in the desert steppe of northwestern China. We identified two significantly differentially expressed leucoanthocyanidin dioxygenase genes (RtLDOX/RtLDOX2) and investigated the function and characteristics of RtLDOX2. RtLDOX2 from R. trigyna was rapidly upregulated by salt, drought, and abscisic acid, consistent with the stress-related cis-regulatory elements in the promoter region. Recombinant RtLDOX2 converted dihydrokaempferol to kaempferol in vitro, and was thus interchangeable with flavonol synthase, a dioxygenase in the flavonoid pathway. Transgenic plants overexpressing RtLDOX2 accumulated more anthocyanin and flavonols under abiotic stresses, speculating that RtLDOX2 may act as a multifunctional dioxygenase in the synthesis of anthocyanins and flavonols. Overexpression of RtLDOX2 enhanced the primary root length, biomass accumulation, and chlorophyll content of salt-, drought-, and ultraviolet-B-stressed transgenic Arabidopsis. Antioxidant enzyme activity; proline content; and expression of antioxidant enzyme, proline biosynthesis, and ion-transporter genes were increased in transgenic plants. Therefore, RtLDOX2 confers tolerance to abiotic stress on transgenic Arabidopsis by promoting the accumulation of anthocyanins and flavonols. This in turn increases reactive oxygen species scavenging and activates other stress responses, such as osmotic adjustment and ion transport, and so improves tolerance to abiotic stresses. [ABSTRACT FROM AUTHOR]

• N addition affected soil inorganic P by changing soil organic C. • N addition affected soil organic P by changing microbial properties. • Effects of N addition on soil P fractions varied with initial soil C:N ratio. Globally increasing atmospheric nitrogen (N) deposition can affect soil phosphorus (P) transformations, yet the pathways and underlying mechanisms are largely unclear. Here, we sampled soils from five larch stands along a soil fertility gradient in northern China that have experienced long-term N addition (>5 years), and measured soil P fractions and biochemical properties. We found that the magnitude and direction of N addition effects on soil inorganic P and organic P fractions significantly varied with initial soil C:N ratio. Specifically, N addition significantly reduced almost all soil inorganic P fractions in the larch stand with the highest soil C:N ratio (18.35). In contrast, N addition significantly elevated NaOH-extractable organic P and total organic P in the larch stand with the highest soil C:N ratio while reduced labile organic P and total organic P in the stand with the lower soil C:N ratio (11.74). N addition-induced changes in inorganic P fractions were significantly correlated with that of soil organic C. Moreover, N addition-induced changes in organic P fractions were significantly correlated with those of microbial biomass and acid phosphatase activity. Taken together, our results indicate that N addition influenced soil P availability and fractions mainly by affecting soil organic C and microbial properties, which can improve our understanding of mechanisms of changes in soil P availability under the context of increasing N deposition. [ABSTRACT FROM AUTHOR]

Composite reflectivity Doppler radar data from June to September of 2007-2010 were used to classify mesoscale convective systems (MCSs) over central east China into seven morphologies. The morphologies included one nonlinear mode (NL) and six linear modes: convective lines with no stratiform precipitation (NS), trailing stratiform precipitation (TS), leading stratiform precipitation (LS), parallel stratiform precipitation (PS), bow echoes (BE), and embedded lines (EL). Nonlinear and linear systems composed 44.7% and 55.3% of total MCSs, respectively, but there was no primary linear mode. All MCS morphologies attained their peak occurrence in July, except BE systems, which peaked in June. On average, TS and PS modes had relatively longer lifespans than did other modes. Significant differences in MCS-produced severe weather existed between dry and moist environments. High winds and hail events were mainly observed in dry environments, and in contrast, short-term intense precipitation occurred more frequently in moist environments. BE systems generated the most severe weather on average, while most TS systems were attendant with short-term intense precipitation and high winds. EL and PS systems were most frequently associated with extreme short-time intense precipitation (≥50 mm h−1) as these systems preferentially developed in moist environments. BE systems generally occurred under strong low-level shear and intermediately moist conditions. LS systems were observed in weak low-level shear, whereas EL systems often developed in relatively stable conditions and weak low- to middle-level shear. The largest instability was present in the environment for NS systems. The environmental parameters for TS systems featured the largest differences between the dry and moist cases. [ABSTRACT FROM AUTHOR]

Radar reflectivity data is crucial to improve initial field of numerical model. However, the method of Ensemble Kalman Filtering (EnKF) can not directly assimilate radar reflectivity data. We explore a method of modifying the initial thermodynamic field of numerical model by using radar reflectivity data. Two experiments are carried out to reveal the forecast improvement of a squall line occurred in the Eastern China by assimilating reflectivity data. One experiment is assimilating some observational data without radar reflectivity data using EnKF method (hereafter called No-Ref experiment), and the other is modifying the initial thermodynamic field using radar reflectivity data after conducting EnKF experiment (called Ref experiment). Compared with the simulation results of No-Ref experiment, the forecast is improved in Ref experiment. The results show that thermodynamic field adjustment leads to the adjustment of the dynamic field, and plays an important role in the improvement of squall line forecast. [ABSTRACT FROM AUTHOR]

Reaumuria trigyna , an endangered recretohalophyte, is a small archaic wild shrub endemic to arid and semiarid plateau regions of Inner Mongolia, China. Based on salt-related transcriptomic data, we isolated a GRX family gene, glutaredoxin like protein (RtGRL1), from R. trigyna that is associated with the removal of active oxygen and regulation of redox status. RtGRL1 encodes a plasma membrane and chloroplast-localized protein induced by salt, cold, drought stress, ABA, and H 2 O 2. In Arabidopsis thaliana , ectopically expressed RtGRL1 positively regulated biomass accumulation, chlorophyll content, germination rate, and primary root length under salt and drought stress. Overexpression of RtGRL1 induced expression of genes related to antioxidant enzymes and proline biosynthesis, thus increasing glutathione biosynthesis, glutathione-dependent detoxification of reactive oxygen species (ROS), and proline content under stress. Changes in RtGRL1 expression consistently affected glutathione/oxidizedglutathione and ascorbate/dehydroascorbate ratios and H 2 O 2 concentrations. Furthermore, RtGRL1 promoted several GSH biosynthesis gene transcripts, decreased leaf Na+ content, and maintained lower Na+/K+ ratios in transgenic A. thaliana compared to wild type plants. These results suggest a critical link between RtGRL1 and ROS modulation, and contribute to a better understanding of the mechanisms governing plant responses to drought and salt stress. • Overexpression of RtGRL1 induced expression of genes related increasing glutathione biosynthesis and proline content under abiotic stress. • RtGRL1 improved plant ability of glutathione-dependent detoxification of reactive oxygen species (H 2 O 2). • RtGRL1 maintained glutathione pool balance and decreased leaf Na+ content, and increased water retention capacity. [ABSTRACT FROM AUTHOR]

Reaumuria trigyna (Reaumuria Linn genus, family Tamaricaceae), an endangered dicotyledonous shrub with the features of a recretohalophyte, is endemic to the Eastern Alxa–Western Ordos area of China. Based on R. trigyna transcriptome data and expression pattern analysis of RtWRKYs , RtWRKY23 , a Group II WRKY transcription factor, was isolated from R. trigyna cDNA. RtWRKY23 was mainly expressed in the stem and was induced by salt, drought, cold, ultraviolet radiation, and ABA treatments, but suppressed by heat treatment. Overexpression of RtWRKY23 in Arabidopsis increased chlorophyll content, root length, and fresh weight of the transgenic lines under salt stress. Real-time quantitative PCR (qPCR) analysis and yeast one-hybrid analysis demonstrated that RtWRKY23 protein directly or indirectly modulated the expression levels of downstream genes, including stress-related genes AtPOD , AtPOD22 , AtPOD23 , AtP5CS1 , AtP5CS2 , and AtPRODH2 , and reproductive development-related genes AtMAF5 , AtHAT1 , and AtANT. RtWRKY23 transgenic Arabidopsis had higher proline content, peroxidase activity, and superoxide anion clearance rate, and lower H 2 O 2 and malondialdehyde content than WT plants under salt stress conditions. Moreover, RtWRKY23 transgenic Arabidopsis exhibited later flowering and shorter pods, but little change in seed yield, compared with WT plants under salt stress. Our study demonstrated that RtWRKY23 not only enhanced salt stress tolerance through maintaining the ROS and osmotic balances in plants, but also participated in the regulation of flowering under salt stress. [ABSTRACT FROM AUTHOR]

Physochlaina physaloides (L.) G. Don is a Physochlaina species of the Solanaceae family and is cultivated extensively as a medicinal plant in Inner Mongolia, China. Its root extracts have been found to treat a variety of diseases, including cancer. The aim of this study is to isolate and identify the bioactive compounds of roots of Physochlaina physaloides (L.) G. Don, and elucidate their cytotoxic effects and related mechanisms. The ethyl acetate (EtOAc) and n-butanol (n-BuOH) components of crude root extract displayed marked cytotoxicity against Hep-G2 and HGC-27 cells. Two compounds—physochloside B and physochloside C—with new skeletons from the n-BuOH fraction and three known compounds (3−5) from the EtOAc fraction were isolated. The cell viability and flow cytometer assay showed that physochlosides B and C exhibited the strongest cytotoxicity of these compounds, including cell cycle blockage and apoptosis at the sub-G1 phase in HGC-27 and Hep-G2 cells, with less severe toxicity to normal cells (GES-1 and L02 cells). Based on the Western blotting results, physochlosides B and C suppressed β-catenin and p-GSK3β expression and downregulated cyclin D1 and C-myc, which are targets of the Wnt/β-catenin pathway, suggesting the involvement of Wnt/β-catenin pathway in the inhibition of HGC-27 and Hep-G2 cells. Above findings indicate a role of physochlosides B and C from Physochlaina physaloides (L.) G. Don roots in suppressing gastric and liver cancer cells. [Display omitted] • Root fractions of Physochlaina physaloides have cytotoxicities against HGC-27 and Hep G2 cells. • Two compounds with new skeleton (physochloside B and physochloside C) were isolated from root fractions. • Physochloside B and physochloside C promote apoptosis of HGC-27 and Hep G2 cells. • Physochloside B and physochloside C induced cell cycle arrest by inhibiting the Wnt/β-catenin pathway. [ABSTRACT FROM AUTHOR]

Tetraena mongolica Maxim is a species of Zygophyllaceae endemic to China. Because few insect pests affect its growth and flowering, we speculated that this plant produces defensive chemicals that are insect repellents or antifeedants. The effects of different fractions from crude stem and leaf extracts on Pieris rapae were examined. The results confirmed that the ethyl acetate (EtOAc) fraction from the stems had insecticidal potential. Five compounds were isolated from the EtOAc fraction: a volatile oil [bis(2-ethylhexyl) benzene-1,2-dicarboxylate (1)], three triterpenoids 2 E -3β-(3,4-dihydroxycinnamoyl)-erythrodiol (2), 2 Z -3β-(3,4-dihydroxycinnamoyl)-erythrodiol (3), and 2 E -3β-(3,4-dihydroxyphenyl)-2-propenoate (4)], and one steroid [β-sitosterol (5)]. Compounds 1 – 5 exhibited different degrees of insecticidal activity, including antifeedant and growth-inhibition effects. Compounds 1 – 5 inhibited the activity of carboxylesterase (CarE) and acetylcholinesterase (AChE) to different degrees. Compound 1 had the strongest antifeedant and growth-inhibition effects, and significantly inhibited the activity of CarE and AChE. Our results indicate that compounds 1 – 4 are the major bioactive insecticidal constituents of Tetraena mongolica. This work should facilitate the development and application of plant-derived botanical pesticides. Unlabelled Image • Five compounds were isolated from the EtOAc fraction from the stem of Tetraena mongolica had insecticidal potential. • The volatile oil had the strongest insecticidal activity, and significantly inhibited the activity of CarE and AChE. • Three triterpenoids had insecticidal activity, and significantly inhibited the activity of AChE. [ABSTRACT FROM AUTHOR]

Oral microbial dysbiosis is known to increase susceptibility of an individual to develop rheumatoid arthritis (RA). Individuals at-risk of RA may undergo different phases of disease progression. In this study, we aim to investigate whether and whereby the oral microbiome communities alter prior to symptoms of RA. Seventy-nine saliva samples were collected from 29 high-risk individuals, who were positive for anti-citrullinated protein antibodies (ACPA) and have no clinical arthritis, 27 RA patients and 23 healthy controls (HCs). The salivary microbiome was examined using 16S ribosomal RNA gene sequencing. Alpha and beta diversity analysis and the linear discriminant analysis were applied to examine the bacterial diversity, community structure and discriminatory taxa between three groups, respectively. The correlation between salivary bacteria and autoantibodies were analyzed. In the "pre-clinical" stages, salivary microbial diversity was significantly reduced comparing to RA patients and HCs. In contrast to HCs, like RA patients, individuals at high-risk for RA showed a reduction in the abundance of genus Defluviitaleaceae_UCG-011 and the species Neisseria oralis , but an expansion of Prevotella _6. Unexpectedly, the relative abundance of Porphyromonas gingivalis , reported as opportunistic pathogens for RA development, was significantly decreased in high-risk individuals. Additionally, we identified four genera in the saliva from high-risk individuals positively correlated with serum ACPA titers, and the other two genera inversely displayed. In summary, we observed a characteristic compositional change of salivary microbes in individuals at high-risk for RA, suggesting that oral microbiota dysbiosis occurs in the "pre-clinical" stage of RA and are correlated with systemic autoimmune features., (Copyright © 2020 Tong, Zheng, Qing, Zhao, Li, Su, Zhang, Zhao, Luo and Liu.)