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Human respiratory syncytial virus (HRSV) is the most prevalent pathogen contributing to acute respiratory tract infections (ARTI) in infants and young children and can lead to significant financial and medical costs. Here, we developed a simultaneous, dual-gene and ultrasensitive detection system for typing HRSV within 60 minutes that needs only minimum laboratory support. Briefly, multiplex integrating reverse transcription-recombinase polymerase amplification (RT-RPA) was performed with viral RNA extracted from nasopharyngeal swabs as a template for the amplification of the specific regions of subtypes A (HRSVA) and B (HRSVB) of HRSV. Next, the Pyrococcus furiosus Argonaute (PfAgo) protein utilizes small 5'-phosphorylated DNA guides to cleave target sequences and produce fluorophore signals (FAM and ROX). Compared with the traditional gold standard (RT-qPCR) and direct immunofluorescence assay (DFA), this method has the additional advantages of easy operation, efficiency and sensitivity, with a limit of detection (LOD) of 1 copy/µL. In terms of clinical sample validation, the diagnostic accuracy of the method for determining the HRSVA and HRSVB infection was greater than 95%. This technique provides a reliable point-of-care (POC) testing for the diagnosis of HRSV-induced ARTI in children and for outbreak management, especially in resource-limited settings.
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RNA Viral , Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Sensibilidade e Especificidade , Humanos , Vírus Sincicial Respiratório Humano/genética , Vírus Sincicial Respiratório Humano/isolamento & purificação , Infecções por Vírus Respiratório Sincicial/diagnóstico , Infecções por Vírus Respiratório Sincicial/virologia , RNA Viral/genética , Lactente , Pyrococcus furiosus/genética , Pyrococcus furiosus/isolamento & purificação , Proteínas Argonautas/genética , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Limite de Detecção , Nasofaringe/virologia , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/virologia , Pré-EscolarRESUMO
Macrocyclic conformations play a crucial role in regulating their properties. Our understanding of the determinants to control macrocyclic conformation interconversion is still in its infancy. Here we present a macrocycle, octamethyl cyclo[4](1,3-(4,6)-dimethylbenzene)[4]((4,6-benzene)(1,3-dicarboxylate) (OC-4), that can exist at 298 K as two stable atropisomers with C2v and C4v symmetry denoted as C2v-OC-4 and C4v-OC-4, respectively. Heating induces the efficient stepwise conversion of C2v- to C4v-OC-4 via a Cs-symmetric intermediate (Cs-OC-4). It differs from the typical transition state-mediated processes of simple C-C single bond rotations. Hydrolysis and further esterification with a countercation dependence promote the generation of C2v- and Cs-OC-4 from C4v-OC-4. In contrast to C2v-OC-4, C4v-OC-4 can bind linear guests to form pseudo-rotaxans, or bind C60 or C70 efficiently. The present study highlights the differences in recognition behavior that can result from conformational interconversion, as well as providing insights into the basic parameters that govern coupled molecular rotations.
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The introduction of precise pore defects into nanocarbon structures results in the emergence of distinct physicochemical characteristics. However, there is a lack of research on non-planar chiral nanographene involving precise pore defects. Herein, we have developed two analogues to the π-extended pentadecabenzo[9]helicene (EP9H) containing embedded pore defects. Each molecule, namely extended dodecabenzo[7]helicene (ED7H; 1) or extended nonabenzo[5]helicene (EN5H; 2), exhibits dual-state emission. Significantly, the value of |glum| of 1 is exceptionally high at 1.41 × 10-2 in solution and BCPL as 254 M-1 cm-1. In PMMA film, |glum| of 1 is 8.56 × 10-3, and in powder film, it is 5.00 × 10-3. This study demonstrates that nanocarbon molecules with pore defects exhibit dual-state emission properties while maintaining quite good chiral luminescence properties. It was distinguished from the aggregation-caused quenching (ACQ) effect corresponding to the nanocarbon without embedded defect. Incorporating pore defects into chiral nanocarbon molecules also simplifies the synthesis process and enhances the solubility of the resulting product. These findings suggest that the introduction of pore defects can be a viable approach to improve nanocarbon molecules.
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A detailed chemical investigation of the Hainan soft coral Lobophytum crassum led to the identification of a class of polyoxygenated cembrane-type macrocyclic diterpenes (1-28), including three new flexible cembranoids, lobophycrasins E-G (2-4), and twenty-five known analogues. Their structures were elucidated by combining extensive spectroscopic data analysis, quantum mechanical-nuclear magnetic resonance (QM-NMR) methods, the modified Mosher's method, X-ray diffraction analysis, and comparison with data reported in the literature. Bioassays revealed that sixteen cembranoids inhibited the proliferation of H1975, MDA-MB231, A549, and H1299 cells. Among them, Compounds 10, 17, and 20 exhibited significant antiproliferative activities with IC50 values of 1.92-8.82 µM, which are very similar to that of the positive control doxorubicin. Molecular mechanistic studies showed that the antitumour activity of Compound 10 was closely related to regulation of the ROR1 and ErbB3 signalling pathways. This study may provide insight into the discovery and utilization of marine macrocyclic cembranoids as lead compounds for anticancer drugs.
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Late Holocene relative sea-level (RSL) data are important to understand the drivers of RSL change, but there is a lack of precise RSL records from the Sunda Shelf. Here, we produced a Late Holocene RSL reconstruction from coral microatolls in Singapore, demonstrating for the first time the utility of Diploastrea heliopora microatolls as sea-level indicators. We produced 12 sea-level index points and three marine limiting data with a precision of < ± 0.2 m (2σ) and < ± 26 years uncertainties (95% highest density region). The data show a RSL fall of 0.31 ± 0.18 m between 2.8 and 0.6 thousand years before present (kyr BP), at rates between - 0.1 ± 0.3 and - 0.2 ± 0.7 mm/year. Surface profiles of the fossil coral microatolls suggest fluctuations in the rate of RSL fall: (1) stable between 2.8 and 2.5 kyr BP; (2) rising at ~ 1.8 kyr BP; and (3) stable from 0.8 to 0.6 kyr BP. The microatoll record shows general agreement with published, high-quality RSL data within the Sunda Shelf. Comparison to a suite of glacial isostatic adjustment (GIA) models indicate preference for lower viscosities in the mantle. However, more high quality and precise Late Holocene RSL data are needed to further evaluate the drivers of RSL change in the region and better constrain GIA model parameters.
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The southwestern region of China is the largest exposed karst area in the world and serves as an important ecological security barrier for the upstream of Yangtze River and Pearl River. Different from the critical zone of non-karst areas, the epikarst, formed by an interwoven network of denudation pores, is the core area of karst critical zone. Water is the most active component that participates in internal material cycle and energy flow within the critical zone. We reviewed relevant research conducted in the southwestern region from three aspects: the characte-rization of critical zone structure, the hydrological processes of soil-epikarst system, and their model simulations. We further proposed potential research hotpots. The main approach involved multi-scale and multi-method integrated observations, as well as interdisciplinary collaboration. Precisely characterizing the eco-hydrological processes of the vegetation-soil-epikarst coupling system was a new trend in the future research. This review would provide scientific reference for further studies on hydrological processes in critical zones and regional hydrological water resource management in karst areas.
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Ecossistema , Hidrologia , China , Solo/química , Movimentos da Água , Rios , Água Subterrânea , Conservação dos Recursos Hídricos/métodos , Monitoramento AmbientalRESUMO
One Stop Crisis Center (OSCC) is a multi-sectorial center aimed to provide medical, social, legal, police and shelter services to survivors of domestic violence, rape, sexual assault, sodomy and child abuse. Although OSCCs have been established for almost three decades in different parts of the world including in Malaysia, there is a lack of a validated instrument to measure the service quality rendered in OSCCs. A validated instrument known as OSCC-Qual was developed using a 5-stage approach where (1) in stage 1, group discussions were conducted among all authors to identify potential items for the instrument; (2) in stage 2, content validation was performed by 13 experts using content validity index and modified kappa; (3) in stage 3, exploratory factor analysis was performed by 141 healthcare staff with experience in managing OSCC cases to validate the items as well as to identify the number of factors in the instrument; (4) in stage 4, confirmatory factor analysis was performed by 110 domestic violence survivors to ascertain the validity of the factors and items retained in stage 3 and (5) in stage 5, forward and backward translation into local Malay and Chinese languages was performed. Results: In stage 1, a total of 42 items were identified. No item was deleted in stage 2. In stage 3, a total of 7 factors (i.e., "information provision", "competency of staff", "professionalism", "supportive environment", "attitude of staff", "multi-sectorial coordination" and "tangibles") were identified. Four items were deleted due to poor factor loading. In stage 4, another 3 items were iteratively removed due to poor factor loading. Discriminant validity was good. Conclusion: With the availability of the 7-factor and 35-item OSCC-Qual instrument, it is hoped that the efficiency of OSCC in achieving its philosophical objectives after three decades of implementation can be unraveled and remedial actions can be taken, if necessary.
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Violência Doméstica , Humanos , Malásia , Feminino , Adulto , Masculino , Inquéritos e Questionários , Análise Fatorial , Reprodutibilidade dos Testes , Qualidade da Assistência à SaúdeRESUMO
OBJECTIVES: To observe the therapeutic effect of transcutaneous electrical acupoint stimulation (TEAS) based on the theory of "qi ascending and descending movement" in patients after general anesthesia laparoscopic cholecystectomy, so as to explore the impact of TEAS on the autonomic nervous system and gastrointestinal function of patients. METHODS: A total of 204 patients scheduled to undergo general anesthesia laparoscopic cholecystectomy were selected and randomly divided into control, double acupoints and multiple acupoints groups, with 68 cases in each group. For patients in the multiple acupoints group, TEAS was applied at Zusanli (ST36), Tiantu (CV22), Danzhong (CV17), Zhongwan (CV12), Taichong (LR3), and Neiguan (PC6) 30 min before anesthesia induction until the end of the surgery. In the double acupoints group, TEAS was applied only at ST36 and PC6. No electrical stimulation was applied in the control group. The postoperative bloating, bowel sound recovery time, first farting time, first defecation time, length of hospital stay, nausea and vomiting were compared among the three groups. Heart rate variability was monitored by twelve-lead electrocardiogram to evaluate the autonomic nervous function of the patients, including the low frequency power/high frequency power ratio (LF/HF), the standard deviation of all sinus RR intervals (SDNN), and the root mean square of difference between successive normal RR intervals (RMSSD). RESULTS: At 6 h and 24 h after surgery, the symptoms of bloating, nausea and vomiting in the multiple acupoints group and double acupoints group were significantly improved compared to the control group (P<0.05), and the multiple acupoints group was superior to the double acupoints group (P<0.05). Compared with the control group, the bowel sound recovery time, first farting time, first defecation time, and length of hospital stay were significantly shorter (P<0.05) in the multiple acupoints group and double acupoints group, and the multiple acupoints group was superior to the double acupoints group (P<0.05). At 1 d and 2 d after surgery, compared with the control group, LF/HF was decreased (P<0.05) while SDNN and RMSSD were increased (P<0.05) in the multiple acupoints group and double acupoints group, and there was a significant difference between the two groups (P<0.05). CONCLUSIONS: TEAS treatment based on the theory of "qi ascending and descending movement" can relieve gastrointestinal dysfunction, reduce early postoperative sympathetic nerve excitement and maintain parasympathetic nerve tension in patients after general anesthesia laparoscopic cholecystectomy, thereby promoting gastrointestinal function recovery.
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Colecistectomia Laparoscópica , Estimulação Elétrica Nervosa Transcutânea , Humanos , Colecistectomia Laparoscópica/efeitos adversos , Pontos de Acupuntura , Qi , Sistema Nervoso Autônomo , Náusea , Vômito , Anestesia GeralRESUMO
The accurate and effective detection of moisture in coal gravels is crucial. Conventional air oven-drying method suffers from prolonged processing times and their disruptive nature. This paper proposes a deep learning-based adaptive fusion method for multiple microwave spectra to non-destructively detect the moisture content of coal gravels. First, a purpose-built free-space measurement platform is employed to acquire microwave spectra of coal samples, encompassing the magnitude and phase spectra of reflection coefficients (S11) and transmission coefficients (S21). Subsequently, a Monte-Carlo cross-validation-based method is adopted to detect and eliminate outliers in the spectra. Furthermore, a novel feature extraction module is proposed, enhancing the traditional U-shaped network using residual learning (ResNet) and the convolutional block attention module (CBAM) to extract and reconstruct subtle spectral features. Inspired by the high-level data fusion, an adaptive spectra fusion method is then introduced that can autonomously balance the contributions between different spectra. The experimental results underscore the advantages of the proposed method, with narrow frequency intervals between 2.50-3.25 GHz, 3.75-4.00 GHz, and 4.75-5.00 GHz exhibiting superior detection accuracy compared to the entire frequency band, achieving R2 = 0.9034, MAE = 1.0254, RMSE = 1.2948 and RPIQ = 6.0630.
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The balance between bone-resorbing osteoclasts and bone-forming osteoblasts is essential for the process of bone remodeling. Excessive osteoclast differentiation plays a pivotal role in the pathogenesis of bone diseases such as rheumatoid arthritis and osteoporosis. In the present study, we examined whether 7,8-epoxy-11-sinulariolide acetate (Esa), a marine natural product present in soft coral Sinularia siaesensis, attenuates inflammation and osteoclastogenesis in vitro. The results indicated that Esa significantly inhibited lipopolysaccharide (LPS)-induced inflammation model of RAW264.7 cells and suppressed receptor activator for nuclear factor-κB ligand (RANKL)-triggered osteoclastogenesis. Esa significantly down-regulated the protein expression of iNOS, COX-2, and TNF-α by inhibiting the NF-κB/MAPK/PI3K pathways and reducing the release of reactive oxygen species (ROS) in RAW264.7 macrophages. Besides, Esa treatment significantly inhibited osteoclast differentiation and suppressed the expression of osteoclast-specific markers such as NFATC1, MMP-9, and CTSK proteins. These findings suggest that Esa may be a potential agent for the maintenance of bone homeostasis associated with inflammation.
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Antozoários , Reabsorção Óssea , Diterpenos , Animais , Osteogênese , Fosfatidilinositol 3-Quinases/metabolismo , Diferenciação Celular , Osteoclastos , NF-kappa B/metabolismo , Inflamação/metabolismo , Antozoários/metabolismo , Ligante RANK/metabolismo , Fatores de Transcrição NFATC/metabolismoRESUMO
In this study, we highlight the impact of catalyst geometry on the formation of O-O bonds in Cu2 and Fe2 catalysts. A series of Cu2 complexes with diverse linkers are designed as electrocatalysts for water oxidation. Interestingly, the catalytic performance of these Cu2 complexes is enhanced as their molecular skeletons become more rigid, which contrasts with the behavior observed in our previous investigation with Fe2 analogs. Moreover, mechanistic studies reveal that the reactivity of the bridging O atom results in distinct pathways for O-O bond formation in Cu2 and Fe2 catalysts. In Cu2 systems, the coupling takes place between a terminal CuIII -OH and a bridging µ-Oâ radical. Whereas in Fe2 systems, it involves the coupling of two terminal Fe-oxo entities. Furthermore, an in-depth structure-activity analysis uncovers the spatial geometric prerequisites for the coupling of the terminal OH with the bridging µ-Oâ radical, ultimately leading to the O-O bond formation. Overall, this study emphasizes the critical role of precisely adjusting the spatial geometry of catalysts to align with the O-O bonding pathway.
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Objective By analyzing relevant literature of long COVID,we aimed to understand the current research status,hotspots and trends in this field.Methods Based on Web of Science core collection data,bibliometric analysis was used as the main research method.The results were visualized with VOSviewer.A comprehensive analysis was performed from various perspectives including trends in publication,journal distribution,highly cited papers,international research collaboration networks,and clusters of keywords,etc.Results The field of long COVID has garnered significant global academic attention.A total of 7 877 related articles were retrievable,with a total citation count of 103 389 and an average citation count of 13.13 per article.Among them,the United States published the most articles(1 780 articles,22.59%),while China ranked fifth in publication volume(686 articles,8.71%).The international scientific cooperation network reflected the close collaborative relationships between countries in long COVID research,predominantly involving the United States,the United Kingdom,Italy,India,and China.Keywords clustering indicated that the current main research focuses in the long COVID field include:clinical manifestations,epidemiological characteristics,risk factors,and mechanisms of occurrence,treatment and rehabilitation measures of long COVID,and its impact on public and social life.Conclusion This article reveals the current state,research hotspots and trends in the long COVID field,providing valuable references for related research institutions,scholars as well as health administrative office.
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Objective:To evaluate the clinical value of combined detection of placenta associated 8 (PLAC8) and platelet activating factor acetylhydrolase (PLA2G7) for early identification of sepsis and non-infectious systemic inflammatory response syndrome (SIRS).Methods:A cross-sectional study was conducted. A total of 189 febrile patients suspected infection who were admitted to Huashan Hospital, Fudan University from October 2022 to April 2023 were included. Based on etiological, laboratory test results and clinical data, patients were classified as infection or non-infection, and further classified as sepsis or non-infectious SIRS according to diagnostic criteria. Real-time fluorescence polymerase chain reaction was used to detect the mRNA levels of PLAC8 and PLA2G7 in peripheral venous blood of patients. Hematology, inflammatory markers including C-reactive protein (CRP), interleukin-6 (IL-6) and procalcitonin, sepsis-related organ failure assessment (SOFA) score, and the difference of cycle threshold (Ct) values between PLA2G7 and PLAC8 ((PLA2G7-PLAC8)ΔCt value))were compared between the sepsis and non-infectious SIRS groups. Statistical comparison was analyzed using Mann-Whitney U test, and the diagnostic performance of (PLA2G7-PLAC8)ΔCt value in discriminating sepsis from non-infectious SIRS was evaluated using receiver operating characteristic curve. Results:Among the 189 febrile patients suspected infection, there were 80 non-infectious patients, including 51 non-infectious SIRS patients, and 109 infection patients, including 53 sepsis patients. The neutrophil ratio, CRP, IL-6, procalcitonin, and SOFA score of non-infectious SIRS patients were lower than those of the sepsis group, and the differences were all statistically significant ( Z=-2.70, -3.11, -2.16, -3.76 and -2.33, respectively, all P<0.05). The (PLA2G7-PLAC8)ΔCt value in the non-infectious SIRS group was 4.38(1.41), which was lower than 8.18 (6.19) in the sepsis group, with a statistically significant difference ( U=193.50, P<0.001). The area under the receiver operating characteristic curve (AUROC) for (PLA2G7-PLAC8)ΔCt value in the differential diagnosis of sepsis and non-infectious SIRS was 0.859, with the optimal cut-off value of 5.86. The sensitivity and specificity were 82.2% and 71.9%, respectively. When combined with procalcitonin, the AUROC was 0.917, with a sensitivity of 95.6% and specificity of 70.6%. Conclusions:The (PLA2G7-PLAC8)ΔCt value in peripheral blood has good clinical value for early identification of sepsis and non-infectious SIRS, especially when combined with procalcitonin, which could further improve the accuracy of differential diagnosis.
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Recently, orbital Hall current has attracted attention as an alternative method to switch the magnetization of ferromagnets. Here we present our findings on electrical switching of the antiferromagnetic state in Mn3Sn/Cr, where despite the much smaller spin Hall angle of Cr, the switching current density is comparable to heavy metal-based heterostructures. However, the inverse process, i.e., spin-to-charge conversion in Cr-based heterostructures, is much less efficient than the Pt-based equivalents, as manifested in the 1 order of magnitude smaller terahertz emission intensity and spin current-induced magnetoresistance. These results in combination with the slow decay of terahertz emission against Cr thickness (diffusion length of â¼11 nm) suggest that the observed magnetic switching can be attributed to orbital current generation in Cr, followed by efficient conversion to spin current. Our work demonstrates the potential of light metals like Cr as efficient orbital/spin current sources for antiferromagnetic spintronics.
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This study mitigated the challenge of head and neck CT angiography by IPA-based time-resolved imaging of contrast kinetics. To this end, 627 cerebral hemorrhage patients with dizziness, brain aneurysm, stroke, or hemorrhagic stroke diagnosis were randomly categorized into three groups, namely, the original dataset (450), verification group (112), and in vivo testified group (65), in the Affiliated BenQ Hospital of Nanjing Medical University. In the first stage, seven risk factors were assigned: age, CTA tube voltage, body surface area, heart rate per minute, cardiac output blood per minute, the actual injected amount of contrast media, and CTA delayed trigger timing. The expectation value of the semi-empirical formula was the CTA number of the patient's left artery (LA). Accordingly, 29 items of the first-order nonlinear equation were calculated via the inverse problem analysis (IPA) technique run in the STATISTICA 7.0 program, yielding a loss function and variance of 3.1837 and 0.8892, respectively. A dimensionless AT was proposed to imply the coincidence, with a lower AT indicating a smaller deviation between theoretical and practical values. The derived formula was confirmed for the verification group of 112 patients, reaching high coincidence, with average ATavg and standard deviation values of 3.57% and 3.06%, respectively. In the second stage, the formula was refined to find the optimal amount of contrast media for the CTA number of LA approaching 400. Finally, the above procedure was applied to head and neck CTA images of the third group of 65 patients, reaching an average CTA number of LA of 407.8 ± 16.2 and finding no significant fluctuations.
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Three new cembranoids (1-3) and a new casbanoid (4), along with three known analogues (5-7), have been isolated from the soft coral Sinularia nanolobata collected off Ximao Island. The structures, including the absolute configurations of new compounds, were established using extensive spectroscopic data analysis, time-dependent density functional theory/electronic circular dichroism (TDDFT-ECD) calculations, and the comparison with spectroscopic data of known compounds. In the in vitro bioassay, compounds 1 and 5 exhibited moderate cytotoxic activities against human erythroleukemia (HEL) cell lines, with IC50 values of 37.1 and 42.4 µM, respectively.
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Antozoários , Diterpenos , Animais , Humanos , Estrutura Molecular , Antozoários/química , Linhagem Celular Tumoral , Diterpenos/farmacologia , Diterpenos/química , ChinaRESUMO
Computational systems biology plays a key role in the discovery of suitable antiviral targets. We designed a cell-specific, constraint-based modeling technique for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected lungs. We used the gene sequence of the alpha variant of SARS-CoV-2 to build a viral biomass reaction (VBR). We also used the mass proportion of lipids between the viral biomass and its host cell to estimate the stoichiometric coefficients of viral lipids in the reaction. We then integrated the VBR, the gene expression of the alpha variant of SARS-CoV-2, and the generic human metabolic network Recon3D to reconstruct a cell-specific genome-scale metabolic model. An antiviral target discovery (AVTD) platform was introduced using this model to identify therapeutic drug targets for combating COVID-19. The AVTD platform not only identified antiviral genes for eliminating viral replication but also predicted side effects of treatments. Our computational results revealed that knocking out dihydroorotate dehydrogenase (DHODH) might reduce the synthesis rate of cytidine-5'-triphosphate and uridine-5'-triphosphate, which terminate the viral building blocks of DNA and RNA for SARS-CoV-2 replication. Our results also indicated that DHODH is a promising antiviral target that causes minor side effects, which is consistent with the results of recent reports. Moreover, we discovered that the genes that participate in the de novo biosynthesis of glycerophospholipids and ceramides become unidentifiable if the VBR does not involve the stoichiometry of lipids.
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COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , COVID-19/genética , Di-Hidro-Orotato Desidrogenase , Antivirais/farmacologia , Pulmão , LipídeosRESUMO
We investigate the 2^{3}S_{1}-2^{3}P_{J} (J=0, 1, 2) transitions in ^{6}Li^{+} using the optical Ramsey technique and achieve the most precise values of the hyperfine splittings of the 2^{3}S_{1} and 2^{3}P_{J} states, with smallest uncertainty of about 10 kHz. The present results reduce the uncertainties of previous experiments by a factor of 5 for the 2^{3}S_{1} state and a factor of 50 for the 2^{3}P_{J} states, and are in better agreement with theoretical values. Combining our measured hyperfine intervals of the 2^{3}S_{1} state with the latest quantum electrodynamic (QED) calculations, the improved Zemach radius of the ^{6}Li nucleus is determined to be 2.44(2) fm, with the uncertainty entirely due to the uncalculated QED effects of order mα^{7}. The result is in sharp disagreement with the value 3.71(16) fm determined from simple models of the nuclear charge and magnetization distribution. We call for a more definitive nuclear physics value of the ^{6}Li Zemach radius.
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Tea is known for having a high catechin content, with the main component being (-)-epigallocatechin gallate (EGCG), which has significant bioactivities, including potential anti-cancer and anti-inflammatory activity. The poor intestinal stability and permeability of EGCG, however, undermine these health-improving benefits. O-methylated EGCG derivatives, found in a few tea cultivars in low levels, have attracted considerable interest due to their increased bioavailability. Here, we identify two O-methyltransferases from tea plant: CsFAOMT1 that has a specific O-methyltransferase activity on the 3''-position of EGCG to generate EGCG3''Me, and CsFAOMT2 that predominantly catalyzes the formation of EGCG4â³Me. In different tea tissues and germplasms, the transcript levels of CsFAOMT1 and CsFAOMT2 are strongly correlated with the amounts of EGCG3''Me and EGCG4''Me, respectively. Furthermore, the crystal structures of CsFAOMT1 and CsFAOMT2 reveal the key residues necessary for 3''- and 4''-O-methylation. These findings may provide guidance for the future development of tea cultivars with high O-methylated catechin content.
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Camellia sinensis , Catequina , Metiltransferases/genética , Disponibilidade Biológica , Camellia sinensis/genética , CháRESUMO
[This retracts the article DOI: 10.1039/C8RA08973F.].