Phytochrome-interacting factors orchestrate hypocotyl adventitious root initiation in Arabidopsis.

Adventitious roots (ARs) are an important type of plant root and display high phenotypic plasticity in response to different environmental stimuli. It is known that photoreceptors inhibit darkness-induced hypocotyl adventitious root (HAR) formation by directly stabilizing Aux/IAA proteins. In this study, we further report that phytochrome-interacting factors (PIFs) plays a central role in HAR initiation by simultaneously inducing the expression of genes involved in auxin biosynthesis, auxin transport and the transcriptional control of root primordium initiation. We found that, on the basis of their activity downstream of phytochrome, PIFs are required for darkness-induced HAR formation. Specifically, PIFs directly bind to the promoters of some genes involved in root formation, including auxin biosynthesis genes YUCCA2 (YUC2) and YUC6, the auxin influx carrier genes AUX1 and LAX3, and the transcription factors WOX5/7 and LBD16/29, to activate their expression. These findings reveal a previously uncharacterized transcriptional regulatory network underlying HAR formation.

A genome-wide association study identifies a transporter for zinc uploading to maize kernels.

The Zn content in cereal seeds is an important trait for crop production as well as for human health. However, little is known about how Zn is loaded to plant seeds. Here, through a genome-wide association study (GWAS), we identify the Zn-NA (nicotianamine) transporter gene ZmYSL2 that is responsible for loading Zn to maize kernels. High promoter sequence variation in ZmYSL2 most likely drives the natural variation in Zn concentrations in maize kernels. ZmYSL2 is specifically localized on the plasma membrane facing the maternal tissue of the basal endosperm transfer cell layer (BETL) and functions in loading Zn-NA into the BETL. Overexpression of ZmYSL2 increases the Zn concentration in the kernels by 31.6%, which achieves the goal of Zn biofortification of maize. These findings resolve the mystery underlying the loading of Zn into plant seeds, providing an efficient strategy for breeding or engineering maize varieties with enriched Zn nutrition.

Antiviral activity of luteolin against porcine epidemic diarrhea virus in silico and in vitro.

BACKGROUND: Porcine epidemic diarrhea virus (PEDV) mainly causes acute and severe porcine epidemic diarrhea (PED), and is highly fatal in neonatal piglets. No reliable therapeutics against the infection exist, which poses a major global health issue for piglets. Luteolin is a flavonoid with anti-viral activity toward several viruses. RESULTS: We evaluated anti-viral effects of luteolin in PEDV-infected Vero and IPEC-J2 cells, and identified IC50 values of 23.87 µM and 68.5 µM, respectively. And found PEDV internalization, replication and release were significantly reduced upon luteolin treatment. As luteolin could bind to human ACE2 and SARS-CoV-2 main protease (Mpro) to contribute viral entry, we first identified that luteolin shares the same core binding site on pACE2 with PEDV-S by molecular docking and exhibited positive pACE2 binding with an affinity constant of 71.6 µM at dose-dependent increases by surface plasmon resonance (SPR) assay. However, pACE2 was incapable of binding to PEDV-S1. Therefore, luteolin inhibited PEDV internalization independent of PEDV-S binding to pACE2. Moreover, luteolin was firmly embedded in the groove of active pocket of Mpro in a three-dimensional docking model, and fluorescence resonance energy transfer (FRET) assays confirmed that luteolin inhibited PEDV Mpro activity. In addition, we also observed PEDV-induced pro-inflammatory cytokine inhibition and Nrf2-induced HO-1 expression. Finally, a drug resistant mutant was isolated after 10 cell culture passages concomitant with increasing luteolin concentrations, with reduced PEDV susceptibility to luteolin identified at passage 10. CONCLUSIONS: Our results push forward that anti-PEDV mechanisms and resistant-PEDV properties for luteolin, which may be used to combat PED.

Smartphone-assisted hydrogel platform based on BSA-CeO2 nanoclusters for dual-mode determination of acetylcholinesterase and organophosphorus pesticides.

A dual-mode sensor was developed for detecting acetylcholinesterase (AChE) and organophosphorus pesticides (OPs) via bifunctional BSA-CeO2 nanoclusters (NCs) with oxidase-mimetic activity and fluorescence property. The dual-mode sensor has the characteristics of self-calibration and self-verification, meeting the needs of different detection conditions and provide more accurate results. The colorimetric sensor and fluorescence sensor have been successfully used for detecting AChE with limit of detection (LOD) of 0.081 mU/mL and 0.056 mU/mL, respectively, while the LOD for OPs were 0.9 ng/mL and 0.78 ng/mL, respectively. The recovery of AChE was 93.9-107.2% and of OPs was 95.8-105.0% in actual samples. A novel strategy was developed to monitor pesticide residues and detect AChE level, which will motivate future work to explore the potential applications of multifunctional nanozymes.

How plants sense and respond to osmotic stress.

Drought is one of the most serious abiotic stresses to land plants. Plants sense and respond to drought stress to survive under water deficiency. Scientists have studied how plants sense drought stress, or osmotic stress caused by drought, ever since Charles Darwin, and gradually obtained clues about osmotic stress sensing and signaling in plants. Osmotic stress is a physical stimulus that triggers many physiological changes at the cellular level, including changes in turgor, cell wall stiffness and integrity, membrane tension, and cell fluid volume, and plants may sense some of these stimuli and trigger downstream responses. In this review, we emphasized water potential and movements in organisms, compared putative signal inputs in cell wall-containing and cell wall-free organisms, prospected how plants sense changes in turgor, membrane tension, and cell fluid volume under osmotic stress according to advances in plants, animals, yeasts, and bacteria, summarized multilevel biochemical and physiological signal outputs, such as plasma membrane nanodomain formation, membrane water permeability, root hydrotropism, root halotropism, Casparian strip and suberin lamellae, and finally proposed a hypothesis that osmotic stress responses are likely to be a cocktail of signaling mediated by multiple osmosensors. We also discussed the core scientific questions, provided perspective about the future directions in this field, and highlighted the importance of robust and smart root systems and efficient source-sink allocations for generating future high-yield stress-resistant crops and plants.

Localization and circulation: vesicle trafficking in regulating plant nutrient homeostasis.

Nutrient homeostasis is essential for plant growth and reproduction. Plants, therefore, have evolved tightly regulated mechanisms for the uptake, translocation, distribution, and storage of mineral nutrients. Considering that inorganic nutrient transport relies on membrane-based transporters and channels, vesicle trafficking, one of the fundamental cell biological processes, has become a hotspot of plant nutrition studies. In this review, we summarize recent advances in the study of how vesicle trafficking regulates nutrient homeostasis to contribute to the adaptation of plants to heterogeneous environments. We also discuss new perspectives on future studies, which may inspire researchers to investigate new approaches to improve the human diet and health by changing the nutrient quality of crops.

Visual detection of fowl adenovirus serotype 4 via a portable CRISPR/Cas13a-based lateral flow assay.

The widespread occurrence of fowl adenovirus serotype 4 (FAdV-4)-induced hepatitis-hydropericardium syndrome (HHS) has led to significant economic losses for the poultry industry. A sensitive, accurate, and practical FAdV-4 diagnostic approach is urgently required to limit the incidence of the disease. In the present study, a practical method for detecting FAdV-4 was developed using the CRISPR/Cas13a system and recombinase-aided amplification. The approach was based on 37°C isothermal detection with visible results being achieved. The detection limit of the target gene with this approach was only 101 copies/µl, making it very sensitive and specific. Clinical samples fared well when tested with the Cas13a detection method. For identifying FAdV-4, this novel detection approach was found to be sensitive, specific, and effective.RESEARCH HIGHLIGHTS First study using the CRISPR/Cas13a-based lateral flow detection assay for FAdV-4 detection.The results can be observed by the naked eye.The developed assay could provide an alternative tool for detection of FAdV-4 with minimal equipment.

A biosensor based on Fe3O4@MXene-Au nanocomposites with high peroxidase-like activity for colorimetric and smartphone-based detection of glucose.

A novel magnetic nanozyme Fe3O4@MXene-Au nanocomposite, which possessed higher peroxidase-like activity than that of Fe3O4 nanoparticles and Fe3O4@MXene nanocomposites, was developed. The outstanding magnetic properties of the nanozyme endowed it with the ability of simple and rapid separation, achieving great recyclability. Based on Fe3O4@MXene-Au nanocomposites and glucose oxidase (Glu Ox), a highly selective colorimetric biosensor for glucose detection was developed. Fe3O4@MXene-Au nanocomposites can catalyze H2O2 produced from glucose catalyzed by glucose oxidase to ·OH and oxidize colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxidized TMB (oxTMB) with a significant absorbance at 652 nm. The linear range of glucose was 0-1.4 mM under optimal conditions, with a limit of detection (LOD) of 0.11 mM. Glucose in human whole blood was successfully detected with satisfactory recoveries. Furthermore, a facile agarose hydrogel detection platform was designed. With smartphone software, glucose detection can be realized by the agarose hydrogel platform, demonstrating the potential in on-site and visual detection of glucose.

Target Recognition in SAR Images by Deep Learning with Training Data Augmentation.

Mass production of high-quality synthetic SAR training imagery is essential for boosting the performance of deep-learning (DL)-based SAR automatic target recognition (ATR) algorithms in an open-world environment. To address this problem, we exploit both the widely used Moving and Stationary Target Acquisition and Recognition (MSTAR) SAR dataset and the Synthetic and Measured Paired Labeled Experiment (SAMPLE) dataset, which consists of selected samples from the MSTAR dataset and their computer-generated synthetic counterparts. A series of data augmentation experiments are carried out. First, the sparsity of the scattering centers of the targets is exploited for new target pose synthesis. Additionally, training data with various clutter backgrounds are synthesized via clutter transfer, so that the neural networks are better prepared to cope with background changes in the test samples. To effectively augment the synthetic SAR imagery in the SAMPLE dataset, a novel contrast-based data augmentation technique is proposed. To improve the robustness of neural networks against out-of-distribution (OOD) samples, the SAR images of ground military vehicles collected by the self-developed MiniSAR system are used as the training data for the adversarial outlier exposure procedure. Simulation results show that the proposed data augmentation methods are effective in improving both the target classification accuracy and the OOD detection performance. The purpose of this work is to establish the foundation for large-scale, open-field implementation of DL-based SAR-ATR systems, which is not only of great value in the sense of theoretical research, but is also potentially meaningful in the aspect of military application.

[Active components and potential mechanism of Taohong Siwu Decoction in regulating ischemic stroke based on target cell trapping combined with network pharmacology, molecular docking, and experimental validation].

The potential anti-stroke active components in Taohong Siwu Decoction(THSWD) were identified by target cell trapping coupled with ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry(UPLC-Q-TOF-MS). The underlying mechanism of active components in THSWD in the treatment of ischemic stroke(IS) was explored by network pharmacology, molecular docking, and experimental validation. The UPLC-Q-TOF-MS technology combined with the UNIFI data analysis platform was used to analyze the composition of the cellular fragmentation fluid after co-incubation of THSWD with target cells. The targets of potential active components and IS were collected by network pharmacology, and the common targets underwent protein-protein interaction(PPI), Gene Ontology(GO), and Kyoto Encyclopedia of Genes and Genomes(KEGG) signaling pathway enrichment analyses. The target cell trapping component-core target-signaling pathway network was constructed, and the active components were molecularly docked to the top targets in the PPI network, followed by pharmacodynamic validation in vitro. Fifteen active components were identified in the target cellular fragmentation fluid, including bicyclic monoterpenes, cyanoglycosides, flavonols, quinoid chalcones, phenylpropanoids, and tannins. As revealed by the analysis of network pharmacology, THSWD presumably regulated PI3K-AKT, FoxO, MAPK, Jak-STAT, VEGF, HIF-1, and other signaling pathways to affect inflammatory cascade reaction, angiogenesis, oxidative stress, pyroptosis, apoptosis, and other pathological processes via paeoniflorin, butylphthalide, dehydrated safflower yellow B, 3,4-dicaffeoylquinic acid, amygdalin, paeoniflorin, and ligusticolactone. Molecular docking and in vitro pharmacodynamic validation revealed that the target cell trapping active components could promote neovascularization in rat brain microvascular endothelial cells(rBMECs) in the oxygen-glucose deprivation/reoxygenation(OGD/R) model. The application of target cell trapping coupled with UPLC-Q-TOF-MS technology can rapidly screen out the potential active components in THSWD. The active components of THSWD can be predicted to intervene in the pathogenesis of IS through network pharmacology, and molecular docking combined with experimental validation can further clarify the efficacy, thus providing a theoretical basis for research ideas on the pharmacodynamic substance basis of traditional Chinese medicine compounds.

[Origin identification of Poria cocos based on hyperspectral imaging technology].

To realize the non-destructive and rapid origin discrimination of Poria cocos in batches, this study established the P. cocos origin recognition model based on hyperspectral imaging combined with machine learning. P. cocos samples from Anhui, Fujian, Guangxi, Hubei, Hunan, Henan and Yunnan were used as the research objects. Hyperspectral data were collected in the visible and near infrared band(V-band, 410-990 nm) and shortwave infrared band(S-band, 950-2 500 nm). The original spectral data were divided into S-band, V-band and full-band. With the original data(RD) of different bands, multiplicative scatter correction(MSC), standard normal variation(SNV), S-G smoothing(SGS), first derivative(FD), second derivative(SD) and other pretreatments were carried out. Then the data were classified according to three different types of producing areas: province, county and batch. The origin identification model was established by partial least squares discriminant analysis(PLS-DA) and linear support vector machine(LinearSVC). Finally, confusion matrix was employed to evaluate the optimal model, with F1 score as the evaluation standard. The results revealed that the origin identification model established by FD combined with LinearSVC had the highest prediction accuracy in full-band range classified by province, V-band range by county and full-band range by batch, which were 99.28%, 98.55% and 97.45%, respectively, and the overall F1 scores of these three models were 99.16%, 98.59% and 97.58%, respectively, indicating excellent performance of these models. Therefore, hyperspectral imaging combined with LinearSVC can realize the non-destructive, accurate and rapid identification of P. cocos from different producing areas in batches, which is conducive to the directional research and production of P. cocos.

[Origin identification of Polygonatum cyrtonema based on hyperspectral data].

In this study, visual-near infrared(VNIR), short-wave infrared(SWIR), and VNIR + SWIR fusion hyperspectral data of Polygonatum cyrtonema from different geographical origins were collected and preprocessed by first derivative(FD), second derivative(SD), Savitzky-Golay smoothing(S-G), standard normalized variate(SNV), multiplicative scatter correction(MSC), FD+S-G, and SD+S-G. Three algorithms, namely random forest(RF), linear support vector classification(LinearSVC), and partial least squares discriminant analysis(PLS-DA), were used to establish the identification models of P. cyrtonema origin from three spatial scales, i.e., province, county, and township, respectively. Successive projection algorithm(SPA) and competitive adaptive reweighted sampling(CARS) were used to screen the characteristic bands, and the P. cyrtonema origin identification models were established according to the selected characteristic bands. The results showed that(1)after FD preprocessing of VNIR+SWIR fusion hyperspectral data, the accuracy of recognition models established using LinearSVC was the highest, reaching 99.97% and 99.82% in the province origin identification model, 100.00% and 99.46% in the county origin identification model, and 99.62% and 98.39% in the township origin identification model. The accuracy of province, county, and township origin identification models reached more than 98.00%.(2)Among the 26 characteristic bands selected by CARS, after FD pretreatment, the accuracy of origin identification models of different spatial scales was the highest using LinearSVC, reaching 98.59% and 97.05% in the province origin identification model, 97.79% and 94.75% in the county origin identification model, and 90.13% and 87.95% in the township origin identification model. The accuracy of identification models of different spatial scales established by 26 characteristic bands reached more than 87.00%. The results show that hyperspectral imaging technology can realize accurate identification of P. cyrtonema origin from different spatial scales.

Phytochrome B inhibits darkness-induced hypocotyl adventitious root formation by stabilizing IAA14 and suppressing ARF7 and ARF19.

Adventitious roots (ARs) are an important root type for plants and display a high phenotypic plasticity in response to different environmental stimuli. Previous studies found that dark-light transition can trigger AR formation from the hypocotyl of etiolated Arabidopsis thaliana, which was used as a model for the identification of regulators of AR biogenesis. However, the central regulatory machinery for darkness-induced hypocotyl AR (HAR) remains elusive. Here, we report that photoreceptors suppress HAR biogenesis through regulating the molecular module essential for lateral roots. We found that hypocotyls embedded in soil or in continuous darkness are able to develop HARs, wherein photoreceptors act as negative regulators. Distinct from wound-induced ARs that require WOX11 and WOX12, darkness-induced HARs are fully dependent on ARF7, ARF19, WOX5/7, and LBD16. Further studies established that PHYB interacts with IAA14, ARF7, and ARF9. The interactions stabilize IAA14 and inhibit the transcriptional activities of ARF7 and ARF19 and thus suppress biogenesis of darkness-induced HARs. This finding not only revealed the central machinery controlling HAR biogenesis but also illustrated that AR formation could be initiated by multiple pathways.

Similarities and differences in iron homeostasis strategies between graminaceous and nongraminaceous plants.

Iron (Fe) homeostasis is essential for both plant development and human nutrition. The maintenance of Fe homeostasis involves a complex network in which Fe signaling nodes and circuits coordinate tightly Fe transporters, ferric reductases, H+ -ATPases, low-molecular-mass metal chelators, and transporters of chelators and Fe-chelate complexes. Early-stage studies have revealed different strategies for Fe homeostasis between graminaceous and nongraminaceous plants. Recent progress has refreshed our understanding of previous knowledge, especially on the uptake, phloem transport and systemic signaling of Fe. This review attempts to summarize recent exciting and potentially influential studies on the various routes of Fe uptake and distribution in plants, focusing on breakthroughs that have changed our understanding of plant Fe nutrition.

Sec24C mediates a Golgi-independent trafficking pathway that is required for tonoplast localisation of ABCC1 and ABCC2.

Protein sorting is an essential biological process in all organisms. Trafficking membrane proteins generally relies on the sorting machinery of the Golgi apparatus. However, many proteins have been found to be delivered to target locations via Golgi-independent pathways, but the mechanisms underlying this delivery system remain unknown. Here, we report that Sec24C mediates the direct secretory trafficking of the phytochelatin transporters ABCC1 and ABCC2 from the endoplasmic reticulum (ER) to prevacuolar compartments (PVCs) in Arabidopsis thaliana. Genetic analysis showed that the sec24c mutants are hypersensitive to cadmium (Cd) and arsenic (As) treatments due to mislocalisation of ABCC1 and ABCC2, which results in defects in the vacuole compartmentalisation of the toxic metals. Furthermore, we found that Sec24C recognises ABCC1 and ABCC2 through direct interactions to mediate their exit from the ER to PVCs, which is independent of brefeldin A-sensitive post-Golgi trafficking pathway. These findings expand our understanding of Golgi-independent trafficking, which also provide key insights regarding the mechanism of tonoplast protein sorting and open a new perspective on the function of Sec24 proteins.

Evaluating Salmonella pullorum dissemination and shedding patterns and antibody production in infected chickens.

BACKGROUND: Pullorum disease caused by Salmonella pullorum is one of the most important infectious diseases in the poultry industry, responsible for causing substantial economic losses globally. On farms, the traditional method to detect S. pullorum infection mainly involves the collection of feces and sera to test for antigens and antibodies, respectively, but the regularity of Salmonella pullorum dissemination in internal organs and shedding patterns and antibody production in infected chickens remains unclear. Herein we aimed to investigate the dissemination of S. pullorum to different organs and bacterial shedding patterns in the faeces as well as serum antibody production post-infection in chickens of different ages. RESULT: In this study, the liver and heart of 2-day-old chickens showed the highest copy numbers of S. pullorum at 6.4 × 106 and 1.9 × 106 copies of DNA target sequences/30 mg, respectively. In case of 10-day-old chickens, the percentage of S. pullorum fecal shedding (0%-40%) and antibody production (0%-56.6%) markedly fluctuated during the entire experiment; furthermore, in case of 42-week-old chickens, the percentage of birds showing S. pullorum shedding in the faeces showed a downward trend (from 63.33% to 6.6% in the oral inoculation group and from 43.3% to 10% in the intraperitoneal injection group), while that of birds showing serum antibody production remained at a high level (38.3% and 80% in the oral inoculation and intraperitoneal injection groups, respectively). We also performed cohabitation experiments, showed that 15% 10-day-old and 3.33% 42-week-old chickens were infected via the horizontal transmission in cohabitation with S. pullorum infected chickens, and revealed a high risk of horizontal transmission of S. pullorum. CONCLUSION: This study systematically evaluated the dissemination of S. pullorum in internal organs and bacterial fecal shedding patterns, and antibody production in infected chickens. Collectively, our findings indicate how to effectively screen S. pullorum-negative chickens on livestock farms and should also help in the development of measures to control and eradicate S. pullorum.

Left ventricular end-systolic volume response post-stress echocardiography: Dilation as a marker of multi-vessel coronary artery disease.

BACKGROUND: Transient ischemic dilation of the left ventricle (LV) during stress echocardiography indicates extensive myocardial ischemia. It remains unclear whether the change of LV end-systolic volume (ESV) or end-diastolic volume (EDV) better correlated with significant coronary artery disease (CAD). Meanwhile, the clinical significance of the extent of the volumetric change post-stress has not been investigated. METHODS: One hundred and five individuals (62 ± 12 years and 75% men) who underwent coronary angiography following exercise treadmill echocardiography were enrolled retrospectively. An additional 30 age- and sex-matched healthy subjects were included for comparison. LV dilation was defined as any increase in LV volume from rest to peak exercise. Patients who had at least two coronary arteries with significant stenosis were considered as having multi-vessel CAD. RESULTS: Thirty-four patients had ESV dilation during exercise echocardiography. On the contrary, ESV decreased at peak exercise in all healthy subjects. Forty-one patients had multi-vessel CAD, and its prevalence was higher in patients with ESV dilation (65% vs 27%, p = 0.001). The extent of ESV increase correlated with CAD severity. ESV dilation is associated with multi-vessel CAD (Odds ratio [OR] 5.02, 95% confidence interval [CI] 2.09 - 12.07, p < 0.001). After adjustment for EDV increase, clinical, electrocardiographic, and echocardiographic variables, the association remained significant (adjusted OR 5.57, 95% CI 1.37-22.64; p = 0.02). CONCLUSIONS: ESV dilation independently correlated with multi-vessel CAD, whereas EDV dilation did not. The amount of ESV increase correlated with the severity of CAD. Our findings provide a rationale for incorporating volume measurements into stress echocardiography practice.

Plant evolution and environmental adaptation unveiled by long-read whole-genome sequencing of Spirodela.

Aquatic plants have to adapt to the environments distinct from where land plants grow. A critical aspect of adaptation is the dynamics of sequence repeats, not resolved in older sequencing platforms due to incomplete and fragmented genome assemblies from short reads. Therefore, we used PacBio long-read sequencing of the Spirodela polyrhiza genome, reaching a 44-fold increase of contiguity with an N50 (a median of contig lengths) of 831 kb and filling 95.4% of gaps left from the previous version. Reconstruction of repeat regions indicates that sequentially nested long terminal repeat (LTR) retrotranspositions occur early in monocot evolution, featured with both prokaryote-like gene-rich regions and eukaryotic repeat islands. Protein-coding genes are reduced to 18,708 gene models supported by 492,435 high-quality full-length PacBio complementary DNA (cDNA) sequences. Different from land plants, the primitive architecture of Spirodela's adventitious roots and lack of lateral roots and root hairs are consistent with dispensable functions of nutrient absorption. Disease-resistant genes encoding antimicrobial peptides and dirigent proteins are expanded by tandem duplications. Remarkably, disease-resistant genes are not only amplified, but also highly expressed, consistent with low levels of 24-nucleotide (nt) small interfering RNA (siRNA) that silence the immune system of land plants, thereby protecting Spirodela against a wide spectrum of pathogens and pests. The long-read sequence information not only sheds light on plant evolution and adaptation to the environment, but also facilitates applications in bioenergy and phytoremediation.

Recyclable molecularly imprinted polymers based on Fe3O4@SiO2 and PAMAM dendrimers for the determination of myosmine in cigarettes.

A selective method for the determination of myosmine (a tobacco alkaloid) was developed using molecularly imprinted polymers (MIPs) based on Fe3O4@SiO2 and PAMAM dendrimers. Fe3O4@SiO2 with excellent magnetism and rapid separation performance was chosen as carrier for the MIPs. Moreover, the MIPs modified with PAMAM dendrimers exhibited a regular structure and abundant functional groups, which improve the efficiency of imprinting sites. The myosmine concentration was measured by HPLC with PDA detector, and the UV detection wavelength was set to 200 nm. The linear range of this assay was 13.2-400 mg/L with a correlation coefficient of 0.999, and the detection limit was 4.0 mg/L (S/N = 3). The MIPs have been used for the determination of myosmine in cigarettes, and the recovery range was 84.2-93.5%, with RSD values in the range 0.41-3.1%. In conclusion, our MIPs combine advantages of simple preparation and remarkable selectivity, which gives them excellent application prospects for the sensitive determination of trace myosmine in tobacco products.

[Simultaneous determination and pharmacokinetic study of five compounds from total extract of Clinopodium chinense in abnormal uterine bleeding rat plasma by UPLC-MS/MS].

Clinopodium chinense, a traditional folk medicinal herb, has been used to treat abnormal uterine bleeding(AUB) for many years. Saponins and flavonoids are the main active components in C. chinense. To study the pharmacokine-tics of multiple components from the total extract of C. chinense(TEC), we established a sensitive and rapid method of ultra-perfor-mance liquid chromatography coupled with tandem mass spectrometry(UPLC-MS/MS) for simultaneous determination of five compounds in the plasma of AUB rats. After validation, the AUB model was established with SD female rats which got pregnant on the same day by gavage with mifepristone(12.4 mg·kg~(-1)) and misoprostol(130 µg·kg~(-1)). The established method was applied to the detection of hesperidin, naringenin, apigenin, saikosaponin a, and buddlejasaponin Ⅳb in AUB rats after the administration of TEC. The pharmacokinetic parameters were calculated by DAS 2.0. The five compounds showed good linear relationship within the detection range. The specificity, accuracy, precision, recovery, matrix effect, and stability of the method all matched the requirements of biolo-gical sample detection. The above 5 compounds were detected in the plasma of AUB rats after the administration of TEC. The C_(max) va-lues of hesperidin, naringenin, apigenin, saikosaponin a, and clinoposide A were 701.6, 429.5, 860.7, 75.1, and 304.1 ng·mL~(-1), respectively. All the compounds owned short half-life and quick elimination rate in vivo, and the large apparent volume of distribution indicated that they were widely distributed in tissues. Being rapid, accurate, and sensitive, this method is suitable for the pharmacokinetic study of extracts of Chinese herbal medicines and provides a reference for the study of pharmacodynamic material basis of C. chinense in treating AUB.