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The 2022 MW6.7 Menyuan earthquake ruptured the western end of the Tianzhu seismic gap, providing an opportunity to study the regional seismogenic characteristics and seismic hazards. Here we use interferometric synthetic aperture radar (InSAR) and seismic data to study the mainshock rupture, early afterslip and the second largest aftershock of the 2022 Menyuan earthquake sequences. Our modeling results show that the mainshock ruptured the Lenglongling fault and the Tuolaishan fault with a maximum slip of ∼3 m. Rapid postseismic transient deformation occurred at the center of the Lenglongling fault. Our afterslip modeling reveals that the majority of afterslip occurred in the deeper part of the Lenglongling fault. A high-angle conjugated faulting event is found at the middle section of the Lenglongling fault. We use the stress inversion to investigate the possible triggering mechanism of the conjugated rupture event. The results indicate the maximum principal stress direction is in ∼222°, forming a ∼22° angle between the conjugated fault of second largest aftershock and the mainshock. The calculated normal stress changes indicate the region is within a pull-apart stress field, which favors such a conjugated rupturing event. Our study will help understand the rupture behavior of such kind of conjugated fault in other regions.

On January 23, 2024, an MW7.0 earthquake occurred in Wushi County. This earthquake was the largest earthquake event in the south Tianshan Fault Zone in the past century. In order to determine the seismogenic structure of the Wushi earthquake and analyze the regional tectonic stress characteristics, we obtained the coseismic deformation field using radar interferometry and pixel offset based on Sentinel-1A data, and estimated the optimal fault geometric parameters applying the Bayesian nonlinear inversion. The results show that the maximum ascending line-of-sight uplift displacement is ~80 cm, and the maximum line-of-sight subsidence is ~16 cm. The line-of-sight coseismic deformation and pixel offsets indicate the significant vertical deformation characteristics of the Wushi earthquake, while the reverse pixel offset results in the azimuth direction of the ascending and descending orbit indicate obvious left-lateral strike-slip on the seismogenic fault. The inversion results show that the seismogenic fault of the Wushi earthquake is SW trending, NW dipping, with an optimal fault dip angle of ~67° and an average rake angle of ~60°, indicating that the coseismic slip is mainly driven by thrust-slip motion with a minor left-lateral strike-slip component. The deformation pattern and fault geometry parameters of the Wushi earthquake are consistent with the kinematics and geometry of the Maidan-Shayilamu fault at the basin-mountain boundary in the southern margin of the Tianshan Mountains. The high dip angle fault with strike- and thrust-slip activity of the Wushi earthquake indicates oblique convergence between the southern Tianshan Mountains and the Tarim Basin, and emphasizes that crustal shortening in the Tianshan region is absorbed by the nascent thrust nappe belts in the piedmont areas and the reverse faults with high dip angles in the orogenic regions.

IntroductionOolong tea, celebrated for its significance in Chinese tea culture, was the subject of investigation in this study.MethodsFive varieties of Minnan oolong tea were sampled, each cultivated under two distinct management approaches: conventional management and natural growth methods. The study aimed to discern variations in sensory attributes, encompassing appearance and liquor color, alongside the analysis of chemical composition.Results and discussionThe results indicated that oolong tea cultivated through conventional manual management generally exhibited qualities in terms of shape and foliage appearance, in contrast to those grown naturally. However, naturally grown oolong tea tended to exhibit more favorable aroma and taste profiles compared to conventionally managed counterparts. Furthermore, the content of water extract, amino acids, polyphenols, caffeine, and other pivotal chemical constituents were typically higher in naturally grown tea varieties compared to conventionally managed ones. Conversely, catechin content was found to be more abundant in traditionally managed bushes than in those grown naturally. These findings emphasize the significance of implementing appropriate natural growth management practices to enhance the quality of Minnan oolong tea and maintain ecological sustainability.

The Kepingtage fold-and-thrust belt in the southwestern Tian Shan in western China hosted the 2020 Mw 6.0 Jiashi earthquake with no apparent surface ruptures. The thrust nappe structure in this region is characterized by moderate-magnitude (Mw5.5-6.5) seismicity, but the seismogenic mechanisms and controlling factors remain under investigation. In this study, we utilized Sentinel-1A synthetic aperture radar satellite data to reconstruct the InSAR coseismic deformation field of the 2020 Jiashi earthquake. To address the limitation imposed by residual orbital phases during the interferometric measurement, we proposed a novel automatic method that combines ascending and descending track data with terrain features for orbit refinement. Eight comparative tests were conducted to prove the effectiveness of the proposed method. Subsequently, we inverted the jointly constrained deformation field after orbit correction to obtain the fault geometric parameters and slip distribution. Our results show that the 2020 Jiashi earthquake is characterized by right-lateral transpressive motion. The smooth interference fringes demonstrate spatially continuous surface uplift and subsidence without detectable coseismic surface ruptures, with a maximum uplift of ∼0.08 m and a maximum subsidence of ∼0.03 m, caused by the subsurface folding due to deep seismic rupture. This event is best fitted by a north-dipping fault plane with a depth of 4.2 km, a dip angle of 11.6°, and a strike of 276° beneath the Keping thrust fault. In terms of various geometric parameters of the fault, the inversion results of this study are generally similar to the focal mechanism solution provided by USGS (MWb), but are different from the focal mechanism solutions of other institutions and previous research results. Combined with the published geological investigations and seismic reflection surveys, we suggest that the seismogenic structure of the 2020 Jiashi earthquake is the lower ramp of the Keping thrust fault and the abrupt fault bend between the lower and upper ramp may limit the propagation of the coseismic rupture to the surface. The limited rupture of this event is dominated by the irregularities in fault geometry along strike and dip, as well as the lower rock strength of the cover above the detachment, which contribute to a deeper understanding of the seismic behavior in fold-and-thrust belts and the moderate-magnitude seismicity in the southwestern Tian Shan region.

Tea is a global economic crop. In the traditional sales model, the quality of tea is difficult to judge via external clues, and it basically relies on consumers to taste and experience it firsthand. However, currently, most e-commerce platforms can only provide consumers with product information and cannot provide experiential services, which strengthens consumers’ purchasing concerns and makes it difficult for them to take practical actions even if they have the desire to purchase tea online. Therefore, this article is based on a questionnaire survey of consumers in China, the world’s largest tea producing and selling country, using unordered multi classification logistic analysis data and calculating the marginal effect proportion of consistency occurrence. Through data analysis, it is shown that there is a serious inconsistency between consumers’ willingness and behavior in choosing online tea purchases. However, under the influence of some internal and external factors, there will also be positive changes; for example, the level of education, online shopping age, familiarity with tea, convenience, product diversification, online evaluation, and other variables will increase the motivation for consumers to convert their purchase intention into actual behavior. In addition, increasing the level of variables such as age, cultural association, cultural experience, convenience, information reliability, award-winning status, familiarity with tea, product diversity, online evaluation, and service attitude in online shopping can enhance consumers’ willingness to shop online and reduce extreme situations where there is neither intention nor behavior. This study provides evidence from a consumer perspective to enhance the efficiency of tea e-commerce marketing and proposes countermeasures and suggestions based on the research results, which could also provide ideas for marketing strategies for tea or other similar agricultural products.

Currently, the mechanism by which light-sensitive albino tea plants respond to light to regulate pigment synthesis has been only partially elucidated. However, few studies have focused on the role of lipid metabolism in the whitening of tea leaves. Therefore, in our study, the leaves of the Baijiguan (BJG) tea tree under shade and light restoration conditions were analyzed by a combination of lipidomics and transcriptomics. The leaf color of BJG was regulated by light intensity and responded to light changes in light by altering the contents and proportions of lipids. According to the correlation analysis, we found three key lipid components that were significantly associated with the chlorophyll SPAD value, namely, MGDG (36:6), DGDG (36:6) and DGDG (34:3). Further weighted gene coexpression network analysis (WGCNA) showed that HY5 TF and GLIP genes may be hub genes involved lipid regulation in albino tea leaves. Our results lay a foundation for further exploration of the color changes in albino tea leaves.

Buried fault identification in plains is one of the important and difficult problems in current active fault research. Seismic activity forces crustal fluid to migrate up, especially along faults, thereby altering the geochemical characteristics of faults. Hyperspectral remote sensing has an extremely high spectral resolution; data derived from hyperspectral remote sensing have the capacity to detect physicochemical characteristics for mining or the subtle recognition of different underground objects. It provides a new method to detect changes in the geochemical characteristics in the fault. This study is trying to locate the fault by spectrum feature. The Xiadian fault was chosen as the study area. Several samples across the fault were collected, and these samples were measured by an ASD Field Spec 3 spectrometer(Analytical Spectral Devices, Boulder, USA, produced in 2008). Continuum removal, the spectral classification method and the wavelet transform technique have been used for spectral analysis. It has been shown that the spectrum of soil in the fault zone has some special characteristics that are different from those of the spectrum away from fault. Four special spectral regions, 550–580 ​nm, 600–700 ​nm, 700–800 ​nm and 800–900 ​nm, have been extracted as the singular ranges. These individual ranges could be used for fault location in the plain area. There is weak absorption near 880 ​nm of the sample in the fault, indicating that Fe3+ content plays an important role in fault identification and that the iron valences can indicate the fault environment. This study also found that the spectral anomalies in space could reflect the intensity of active tectonics to a certain extent. Therefore, spectral features have the potential to identify a buried faults. This study is the first to use spectroscopic techniques to analyze active tectonics, and there is a new discovery. This new discovery provides the basis for the application of remote sensing in the study of active tectonics.

There is increasing interest in the production and consumption of tea (Camellia sinensis L.) processed from purple–leaved cultivar due to their high anthocyanin content and health benefits. However, how and why seasonal changes affect anthocyanin accumulation in young tea leaves still remains obscured. In this study, anthocyanin and abscisic acid (ABA) contents in young leaves of Zifuxing 1 (ZFX1), a cultivar with new shoots turning to purple in Wuyi Mountain, a key tea production region in China, were monitored over four seasons. Young leaves produced in September were highly purplish, which was accompanied with higher anthocyanin and ABA contents. Among the environmental factors, the light intensity in particular was closely correlated with anthocyanin and ABA contents. A shade experiment also indicated that anthocyanin content significantly decreased after 168 h growth under 75% shade, but ABA treatment under the shade conditions sustained anthocyanin content. To confirm the involvement of ABA in the modulation of anthocyanin accumulation, anthocyanin, carotenoids, chlorophyll, ABA, jasmonic acid (JA), and salicylic acid (SA) in the young leaves of four cultivars, including ZFX1, Zijuan (ZJ), wherein leaves are completely purple, Rougui (RG) and Fudingdabaicha (FDDB) wherein leaves are green, were analyzed, and antioxidant activities of the leaf extracts were tested. Results showed that ABA, not other tested hormones, was significantly correlated with anthocyanin accumulation in the purple–leaved cultivars. Cultivars with higher anthocyanin contents exhibited higher antioxidant activities. Subsequently, ZFX1 plants were grown under full sun and treated with ABA and fluridone (Flu), an ABA inhibitor. ABA treatment elevated anthocyanin level but decreased chlorophyll contents. The reverse was true to those treated with Flu. To pursue a better understanding of ABA involvement in anthocyanin accumulation, RNA–Seq was used to analyze transcript differences among ABA– or Flu–treated and untreated ZFX1 plants. Results indicated that the differentially expressed genes in ABA or Flu treatment were mainly ABA signal sensing and metabolism–related genes, anthocyanin accumulation-related genes, light–responsive genes, and key regulatory MYB transcription factors. Taking all the results into account, a model for anthocyanin accumulation in ZFX1 cultivar was proposed: high light intensity caused reactive oxygen stress, which triggered the biosynthesis of ABA; ABA interactions with transcription factors, such as MYB-enhanced anthocyanin biosynthesis limited chlorophyll and carotenoid accumulation; and transport of anthocyanin to vacuoles resulting in the young leaves of ZFX1 with purplish coloration. Further research is warranted to test this model.

The tectonic deformation of a series of NWW-trending compressional band-shaped mountains and fault zones in the Qilian Shan, northeastern Tibet, plays an important role in absorbing the north–south crustal shortening of the Tibetan Plateau and accommodating the sinistral strike-slip of the Altyn Tagh fault. However, the deformation pattern of these mountains and fault zones in response to crustal shortening and sinistral strike-slip remains to be investigated. In this study, we present the slope map and swath profiles of the western Qilian Shan extracted from high-resolution digital elevation model (DEM) data and the fluvial geomorphologic characteristics of the Baiyang river in the northwestern Qilian Shan. Our data indicate that the crustal uplift of the northern Qilian Shan is stronger than that of the central and southern ranges of the Qilian Shan because of the high-terrain relief and stronger erosion. In addition, the deformed terraces of the Baiyang river documented the activity of NWW-trending faults in the western Qilian Shan. Based on the longitudinal profiles and ages of the deformed river terraces, the vertical slip rates of the Changma, Yumen, and Bainan faults in the western Qilian Shan since ∼60 ka were constrained to be 0.31 ± 0.06, 0.33 ± 0.02, and 0.24 ± 0.02 mm/a, respectively. Based on the comparison with previous studies, we noticed that the rate of the vertical slip since the Late Quaternary of the northern Qilian fault of 1.5–2 mm/a is significantly higher than that of the Changma fault of 0.3–0.6 mm/a, which matches the terrain relief in the Qilian Shan and demonstrates that the northern Qilian Shan has been rising faster than its southern ranges. From the slip rates of the NWW-trending faults in the western Qilian Shan, we suggest that the crustal shortening is widely distributed in the NWW-trending compressional orogenic belts and fault zones across the Qilian Shan, among which the northern Qilian Shan and its frontal thrust system absorb the greatest shortening amount, whereas strike-slip faults within the Qilian Shan accommodate most of the sinistral strike-slip of the Altyn Tagh fault.

Lanthanum can affect the growth and development of the tea plant. Tieguanyin (TGY) and Shuixian (SX) cultivars of Camellia sinensis were selected to explore the mechanism underlying the accumulation of lanthanum (tea plants’ most accumulated rare earth element) through proteomics. Roots and fresh leaves of TGY and SX with low- and high-accumulation potential for lanthanum, respectively, were studied; 845 differentially expressed proteins (DEPs) were identified. Gene ontology analysis showed that DEPs were involved in redox processes and related to molecular functions. Kyoto Encyclopedia of Genes and Genomes metabolic pathway analysis showed that DEPs were associated with glutathione (GSH) and α-linolenic acid metabolism, plant pathogen interaction, and oxidative phosphorylation. Thirty-seven proteins in the GSH metabolism pathway showed significant differences, wherein 18 GSH S-transferases showed differential expression patterns in the root system. Compared with the control, expression ratios of GST (TEA004130.1) and GST (TEA032216.1) in TGY leaves were 6.84 and 4.06, respectively, after lanthanum treatment; these were significantly higher than those in SX leaves. The LOX2.1 (TEA011765.1) and LOX2.1 (TEA011776.1) expression ratios in the α-linolenic acid metabolic pathway were 2.44 and 6.43, respectively, in TGY roots, which were significantly higher than those in SX roots. The synthesis of specific substances induces lanthanum-associated defense responses in TGY, which is of great significance for plant yield stability.

Raffinose synthetase (RS) is a key enzyme in the process of raffinose (Raf) synthesis and is involved in plant development and stress responses through regulating Raf content. As a sweetener, Raf makes an important contribution to the sweet taste of white tea. However, studies on the identification, analysis and transcriptional regulation of CsRSs (Camellia sinensis RS genes) are still lacking. In this study, nine CsRSs were identified from the tea plant (Camellia sinensis) genome database. The CsRSs were classified into five groups in the phylogenetic tree. Expression level analysis showed that the CsRSs varied in different parts of the tea plant. Transcriptome data showed that CsRSs could respond to persistent drought and cold acclimation. Except for CsRS5 and CsRS9, the expression pattern of all CsRSs increased at 12 h and decreased at 30 h during the withering process of white tea, consistent with the change trend of the Raf content. Furthermore, combining yeast one-hybrid assays with expression analysis, we found that CsDBB could potentially regulate the expression of CsRS8. Our results provide a new perspective for further research into the characterization of CsRS genes and the formation of the white tea flavour.

Understanding the striking diversity of the angiosperms is a paramount issue in biology and of interest to biologists. The Millettiod legumes is one of the most hyper-diverse groups of the legume family, containing many economically important medicine, furniture and craft species. In the present study, we explore how the interplay of past climate change, ecological opportunities and functional traits’ evolution may have triggered diversification of the Millettiod legumes. Using a comprehensive species-level phylogeny from three plastid markers, we estimate divergence times, infer habit shifts, test the phylogenetic and temporal diversification heterogeneity, and reconstruct ancestral biogeographical ranges. We found that three dramatic accumulations of the Millettiod legumes occurred during the Miocene. The rapid diversification of the Millettiod legumes in the Miocene was driven by ecological opportunities created by the emergence of new niches and range expansion. Additionally, habit shifts and the switch between biomes might have facilitated the rapid diversification of the Millettiod legumes. The Millettiod legumes provide an excellent case for supporting the idea that the interplay of functional traits, biomes, and climatic and geographic factors drives evolutionary success.

Panyong Congou black tea (PCT) is one of the most representative and historically famous Congou black teas in China and has been gaining more and more attention for its beneficial health properties. Currently, four grades of PCT are available, based on the raw leaf materials and consumer palatability. The chemical profiles distinguishing different grades of PCT are yet to be defined, nor has the relationship with grade been evaluated. In the present study, chemometric analysis showed that epigallocatechin (EGC), catechin (C), polyphenols, gallic acid (GA), and free amino acids are grade related bio-markers of PCT. These compounds are associated with the sweet and mellow aftertaste of PCT. A total of 34 volatile components were identified, of which the three component types with the highest relative percentages were alcohols (51.34–52.51%), ketones (27.31–30.28%), and aldehydes (12.70–13.18%). Additionally, our results revealed that sweet floral and fruity aromas were positively correlated with six volatile organic compounds (VOCs), 1-pentanol, propyl hexanoate, linalool, cyclohexanone, hexanal, and 2,5-dimethylpyrazine. Clear discrimination was achieved using orthogonal projections to latent structures discriminant analysis (OPLS-DA). The findings provide vital information on the characteristic flavor of each grade of PCT.

The Nyainrong microcontinent carries key information about the ongoing evolution of the central Tibetan Plateau. The 2021 Mw 5.7 Nagqu earthquake is the largest instrumentally recorded event inside this microcontinent, which provides an ideal opportunity to elucidate the influence of this ancient microcontinent on the seismogenic mechanisms, stress heterogeneity and strain partitioning across the Tibetan Plateau. Here, we constrain the seismogenic fault geometry and distributed fault slip using Interferometric Synthetic Aperture Radar (InSAR) observations. By using the regional focal mechanism solutions, we invert the stress regimes surrounding the Nyainrong microcontinent. Our analysis demonstrates that the mainshock was caused by a normal fault with a comparable sinistral strike-slip component on a North-West dipping fault plane. The Nyainrong microcontinent is surrounded by a dominant normal faulting stress regime to the northeast and a dominant strike-slip stress regime to the southwest. Moreover, the clockwise rotation of the maximum horizontal stress (SHmax) from the southwest to the northeast is ~20°. This indicates that the Nyainrong microcontinent is involved in the mainshock occurrence as well as regional stress heterogeneity, and strain partitioning. Our results highlight the significance of the ancient microcontinent in the tectonic evolution of the Tibetan Plateau.

Abstract Bladder cancer risk is 3‐4 times higher in men than women, but the reason is poorly understood. In mice, male bladder is also more susceptible than female bladder to 4‐aminobiphenyl (ABP), a major human bladder carcinogen; however, female liver is more susceptible than male liver to ABP. We investigated the role of sulfotransferase (Sult) in gender‐related bladder and liver susceptibility to ABP. Sulfation reactions of aromatic amine bladder carcinogens catalyzed by Sult may generate highly unstable and toxic metabolites. Therefore, liver Sult may decrease bladder exposure to carcinogens by promoting their toxic reactions in the liver. Notably, the expression of several liver Sults is suppressed by androgen in male mice. Here, we show that two Sults are critical for gender‐related bladder susceptibility to ABP in mice. We measured tissue level of N‐(deoxyguanosin‐8‐yl)‐4‐aminobiphenyl (dG‐C8‐ABP), a principal ABP‐DNA adduct, as readout of tissue susceptibility to ABP. We identified Sutl1a1 and to a lesser extent Sult1d1 as Sults that promote dG‐C8‐ABP formation in hepatic cells. In mice, gender gap in bladder susceptibility to ABP was narrowed by knocking out Sult1a1 and was almost totally eliminated by knocking out both Sutl1a1 and Sult1d1. This was accompanied by dramatic decrease in ABP genotoxicity in the liver (>97%). These results show the strong impact of the Sults on bladder and liver susceptibility to a human carcinogen. Because liver expression of both Sult1a1 and Sutl1d1 is suppressed by androgen in male mice, our results suggest that androgen renders bladder more exposed to ABP in male mice by suppressing Sult‐mediated ABP metabolism in liver, which increases bladder delivery of carcinogenic metabolites.

The flavor differences in Oolong tea from different producing areas are caused by its complex differential compounds. In this study, representative samples of Oolong tea from four countries were collected, and their differential nonvolatile compounds were analyzed by a combination of widely targeted metabolomics, chemometrics, and quantitative taste evaluation. A total of 801 nonvolatile compounds were detected, which could be divided into 16 categories. We found that the difference in these compounds’ content among Oolong teas from three producing areas in China was the largest. There were 370 differential compounds related to the producing areas of Oolong tea, which were mainly distributed in 67 Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways. In total, 81 differential nonvolatile compounds made important contributions to the taste differences in Oolong tea from different producing areas, among which the number of flavonoids was the largest. Finally, the characteristic compounds of Oolong tea in six producing areas were screened. This study comprehensively identifies the nonvolatile compounds of Oolong tea in different producing areas for the first time, which provides a basis for the analysis of flavor characteristics, quality directional control, and the identification and protection of geographical landmark agricultural products of Oolong tea from different producing areas.

Regionality is a term used in the tea industry to describe the particular style of tea produced by a growing region. Determining the characteristics of the tea of specific regions can help growers predict tea plant quality before harvesting and eventually production. As such, in this study, we collected representative Oolong tea samples from 15 regions in 8 countries. Quantitative description analysis (QDA) and a flavor wheel were used to analyze their sensory characteristics. Chemometrics was used to screen the phytochemical components that significantly contribute to the taste of Oolong tea. We preliminarily obtained 35 sensory characteristic descriptors and constructed a flavor wheel for Oolong tea. We found that Oolong tea in each region has unique sensory quality characteristics. The content of thirteen phytochemical components of Oolong tea in different regions widely varied, and the average coefficient of variation was 45.56%. Among of them, we found the largest difference in free amino acids. We identified the relationship between taste sub-attributes, and the thirteen phytochemical components was found through correlation analysis. Finally, we selected phytochemical components with significant effects on five taste sub-attributes that were selected from the thirteen detected phytochemical components. The construction of the Oolong tea flavor wheel can help realize the qualitative and quantitative sensory evaluation of Oolong tea from different origins and contribute to the quality identification and directional improvement of Oolong tea products.

Low density lipoprotein receptor-related protein 6 (LRP6), a Wnt co-receptor, induces multiple functions in various organs. We recently reported cardiac specific LRP6 deficiency caused cardiac dysfunction in mice. Whether cardiomyocyte-expressed LRP6 protects hearts against ischemic stress is largely unknown. Here, we investigated the effects of cardiac LRP6 in response to ischemic reperfusion (I/R) injury. Tamoxifen inducible cardiac specific LRP6 overexpression mice were generated to build I/R model by occlusion of the left anterior descending (LAD) coronary artery for 40 min and subsequent release of specific time. Cardiac specific LRP6 overexpression significantly ameliorated myocardial I/R injury as characterized by the improved cardiac function, strain pattern and infarct area at 24 h after reperfusion. I/R induced-apoptosis and endoplasmic reticulum (ER) stress were greatly inhibited by LRP6 overexpression in cardiomyocytes. LRP6 overexpression enhanced the expression of heat shock transcription factor-1(HSF1) and heat shock proteins (HSPs), the level of p-glycogen synthase kinase 3β(GSK3β)(S9) and p-AMPK under I/R. HSF1 inhibitor deteriorated the apoptosis and decreased p-GSK3β(S9) level in LRP6 overexpressed –cardiomyocytes treated with H2O2. Si-HSF1 or overexpression of active GSK3β significantly attenuated the increased expression of HSF1 and p-AMPK, and the inhibition of apoptosis and ER stress induced by LRP6 overexpression in H2O2-treated cardiomyocytes. AMPK inhibitor suppressed the increase in p-GSK3β (S9) level but didn’t alter HSF1 nucleus expression in LRP6 overexpressed-cardiomyocytes treated with H2O2. Active GSK3β, but not AMPK inhibitor, attenuated the inhibition of ubiquitination of HSF1 induced by LRP6-overexpressed-cardiomyocytes treated with H2O2. LRP6 overexpression increased interaction of HSF1 and GSK3β which may be involved in the reciprocal regulation under oxidative stress. In conclusion, cardiac LRP6 overexpression significantly inhibits cardiomyocyte apoptosis and ameliorates myocardial I/R injury by the crosstalk of HSF1 and GSK3β signaling.

Background/Aims: To investigate whether nucleosome assembly protein 1-like 1 (Nap1l1) regulates the proliferation of induced pluripotent stem cells (iPSC) and the potential mechanisms. Methods: Nap1l1-knockdown-iPSC and Nap1l1-overexpression-iPSC were constructed by transfection of lentiviral particles. The proliferation of iPSC was detected by MTT analysis, and cell cycle was analyzed by flow cytometry. Results: Nap1l1 overexpression promoted iPSC proliferation and induced G2/M transition compared to their control iPSC while Nap1l1-knockdown-iPSC dramatically displayed the reduced proliferation and accumulated G2/M phase cells. Further analysis showed that Nap1l1 overexpression in iPSC increased the expression of cyclin B1, downregulated the expression of p21 and p27, while knockdown of Nap1l1 showed the opposite effects. In addition, overexpression of Nap1l1 promoted the phosphorylation of AKT and ERK in iPSC, while knockdown of Nap1l1 inhibited the effects. However, these effects displayed in Nap1l1-overexpression-iPSC were greatly suppressed by the inhibition of AKT or ERK signaling. Conclusions: The results indicate that Nap1l1 promotes the proliferation of iPSC attributable to G2/M transition caused by downregulation of p27 and p21, and upregulation of cyclin B1, the activation of AKT or ERK is involved in the process. The present study has revealed a novel molecular mechanism involved in the proliferation of iPSC.

Background/Aims: Angiotensin II (AngII) type 1 receptor (AT1R) could be activated by mechanical stress without the involvement of AngII during the development of cardiac hypertrophy. We aimed to identify sensing sites of AT1R for activation by mechanical stretch. Methods: We constructed several site-directed mutations of AT1R (AT1RK199Q, AT1RL212F, AT1RQ257A and AT1RC289A), transfected them respectively into COS7 cells or angiotensinogen knockout cardiomyocytes (ATG−/−-CMs), and observed cellular events after mechanical stretch. Results: AngII-induced phosphorylation of ERKs and Jak2, and redistribution of Gαq11 in AT1RWT- COS7 or -ATG−/−-CMs were dramatically decreased in AT1RK199Q- or AT1RQ257A- COS7 cells or -ATG−/−-CMs, while those effects induced by mechanical stretch were greatly suppressed in COS7 cells or ATG−/−-CMs expressing AT1RL212F, AT1RQ257A or AT1RC289A compared with these cells expressing AT1RWT. AngII-induced hypertrophic responses (the increase in hypertrophic genes expression and cross-sectional area) in AT1RWT- ATG−/−-CMs were partly abolished in AT1RK199Q-ATG−/−-CMs or AT1RQ257A-ATG−/−-CMs, while these responses induced by mechanical stretch were greatly inhibited in ATG−/−-CMs overexpressing AT1RL212F, AT1RQ257A or AT1RC289A. Conclusion: These results indicated that Leu212, Gln257 and Cys289 in AT1R are not only sensing sites for mechanical stretch but also functional amino residues for activation of the receptor and cardiomyocytes hypertrophy induced by mechanical stretch.

Plasma urotensin II (UII) has been observed to be raised in patients with acute myocardial infarction; suggesting a possible cardiac protective role for this peptide. However, the molecular mechanism is unclear. Here, we treated cultured cardiomyocytes with H2O2 to induce oxidative stress; observed the effect of UII on H2O2-induced apoptosis and explored potential mechanisms. UII pretreatment significantly reduced the number of apoptotic cardiomyocytes induced by H2O2; and it partly abolished the increase of pro-apoptotic protein Bax and the decrease of anti-apoptotic protein Bcl-2 in cardiomyocytes induced by H2O2. SiRNA targeted to the urotensin II receptor (UT) greatly inhibited these effects. Further analysis revealed that UII increased the production of hydrogen sulfide (H2S) and the level of cystathionine-γ-lyase (CSE) by activating the ERK signaling in H2O2-treated-cardiomyocytes. Si-CSE or ERK inhibitor not only greatly inhibited the increase in CSE level or the phosphorylation of ERK induced by UII but also reversed anti-apoptosis of UII in H2O2-treated-cadiomyocytes. In conclusion, UII rapidly promoted the phosphorylation of ERK and upregulated CSE level and H2S production, which in turn activated ERK signaling to protect cardiomyocytes from apoptosis under oxidative stress. These results suggest that increased plasma UII level may protect cardiomyocytes at the early-phase of acute myocardial infarction in patients.

Tea products made from purple leaves are highly preferred by consumers due to the health benefits. This study developed a proteome reference map related to color changes during leaf growth in tea (Camellia sinensis) plant with purple young shoots using two-dimensional electrophoresis (2-DE). Forty-six differentially expressed proteins were detected in the gel and successfully identified by using MALDI-TOF/TOF-MS. The pronounced changes in the proteomic profile between tender purple leaves (TPL) and mature green leaves (MGL) included: 1) the lower activity of proteins associated with CO2 assimilation, energy metabolism and photo flux efficiency and higher content of anthocyanins in TPL than those in MGL may protect tender leaves against photo-damage; 2) the higher abundance of chalcone synthase (CHS), chalcone isomerase (CHI) and flavonol synthase (FLS) likely contributes to the synthesis of anthocyanins, catechins and flavonols in TPL tissues; 3) higher abundance of stress response proteins, such as glutathione S-transferases (GST) and phospholipid hydroperoxide glutathione peroxidase (PHGPx), could enhance the tolerance of TPL tissues to adverse condition in; and 4) the increased abundance of proteins related to protein synthesis, nucleic acids and cell wall proteins should be beneficial for the proliferation and expansion of leaf cell in TPL tissues. qPCR analysis showed that the expression of differentially abundant proteins was regulated at the transcriptional level. Therefore, the results indicated that higher abundance of CHI and CHS may account for the production of the purple-shoot phenotype in Wuyiqizhong 18 and thereby, enhancing the anthocyanin biosynthesis. The higher abundance of glutamine synthetase (GS) proteins related to the theanine biosynthesis may improve the flavor of tea products from TPL materials. Thus, this work should help to understand the molecular mechanisms underlying the changes in leaf color alteration.