Nudix hydrolase WvNUDX24 is involved in borneol biosynthesis in Wurfbainia villosa.

Borneol, camphor, and bornyl acetate are highly promising monoterpenoids widely used in medicine, flavor, food, and chemical applications. Bornyl diphosphate (BPP) serves as a common precursor for the biosynthesis of these monoterpenoids. Although bornyl diphosphate synthase (BPPS) that catalyzes the cyclization of geranyl diphosphate (GPP) to BPP has been identified in multiple plants, the enzyme responsible for the hydrolysis of BPP to produce borneol has not been reported. Here, we conducted in vitro and in vivo functional characterization to identify the Nudix hydrolase WvNUDX24 from W. villosa, which specifically catalyzes the hydrolysis of BPP to generate bornyl phosphate (BP), and then BP forms borneol under the action of phosphatase. Subcellular localization experiments indicated that the hydrolysis of BPP likely occurs in the cytoplasm. Furthermore, site-directed mutagenesis experiments revealed that four critical residues (R84, S96, P98, and G99) for the hydrolysis activity of WvNUDX24. Additionally, the functional identification of phosphatidic acid phosphatase (PAP) demonstrated that WvPAP5 and WvPAP10 were able to hydrolyze geranylgeranyl diphosphate (GGPP) and farnesyl diphosphate (FPP) to generate geranylgeranyl phosphate (GGP) and farnesyl phosphate (FP), respectively, but could not hydrolyze BPP, GPP, and neryl diphosphate (NPP) to produce corresponding monophosphate products. These findings highlight the essential role of WvNUDX24 in the first step of BPP hydrolysis to produce borneol and provide genetic elements for the production of BPP-related terpenoids through plant metabolic engineering and synthetic biology.

HIV Immunocapture Reveals Particles Expressed in Semen Under Integrase Strand Transfer Inhibitor-Based Therapy Are Largely Myeloid Cell-Derived and Disparate.

As use of human immunodeficiency virus (HIV) integrase strand transfer inhibitors (INSTI) increases and formulations are being developed for maintenance therapies and chemoprophylaxis, assessing virus suppression under INSTI-based regimens in prevention-relevant biologic compartments, such as the male genital tract, is timely. We used cell-source marker virion immunocapture to examine amplification of particle RNA then assessed the phylogenetic relatedness of seminal and blood viral sequences from men with HIV who were prescribed INSTI-based regimens. Seminal plasma immunocaptures yielded amplifiable virion RNA from 13 of 24 (54%) men, and the sequences were primarily associated with markers indicative of macrophage and resident dendritic cell sources. Genetic distances were greatest (>2%) between seminal virions and circulating proviruses, pointing to ongoing low-level expression from tissue-resident cells. While the low levels in semen predict an improbable likelihood of transmission, viruses with large genetic distances are expressed under potent INSTI therapy and have implications for determining epidemiologic linkages if adherence is suboptimal.

Comparing genomes of Fructus Amomi-producing species reveals genetic basis of volatile terpenoid divergence.

Wurfbainia longiligularis and Wurfbainia villosa are both rich in volatile terpenoids and are 2 primary plant sources of Fructus Amomi used for curing gastrointestinal diseases. Metabolomic profiling has demonstrated that bornyl diphosphate (BPP)-related terpenoids are more abundant in the W. villosa seeds and have a wider tissue distribution in W. longiligularis. To explore the genetic mechanisms underlying the volatile terpenoid divergence, a high-quality chromosome-level genome of W. longiligularis (2.29 Gb, contig N50 of 80.39 Mb) was assembled. Functional characterization of 17 terpene synthases (WlTPSs) revealed that WlBPPS, along with WlTPS 24/26/28 with bornyl diphosphate synthase (BPPS) activity, contributes to the wider tissue distribution of BPP-related terpenoids in W. longiligularis compared to W. villosa. Furthermore, transgenic Nicotiana tabacum showed that the GCN4-motif element positively regulates seed expression of WvBPPS and thus promotes the enrichment of BPP-related terpenoids in W. villosa seeds. Systematic identification and analysis of candidate TPS in 29 monocot plants from 16 families indicated that substantial expansion of TPS-a and TPS-b subfamily genes in Zingiberaceae may have driven increased diversity and production of volatile terpenoids. Evolutionary analysis and functional identification of BPPS genes showed that BPP-related terpenoids may be distributed only in the Zingiberaceae of monocot plants. This research provides valuable genomic resources for breeding and improving Fructus Amomi with medicinal and edible value and sheds light on the evolution of terpenoid biosynthesis in Zingiberaceae.

A novel sustainable immunoassay for sensitive detection of atrazine based on the anti-idiotypic nanobody and recombinant full-length antibody.

Immunoassays have been widely used to determine small-molecule compounds in food and the environment, meeting the challenge of obtaining false positive or negative results because of the variance in the batches of antibodies and antigens. To resolve this problem, atrazine (ATR) was used as a target, and anti-idiotypic nanobodies for ATR (AI-Nbs) and a recombinant full-length antibody against ATR (ATR-rAb) were prepared for the development of a sustainable enzyme-linked immunosorbent assay (ELISA). AI-Nb-7, AI-Nb-58, and AI-Nb-66 were selected from an immune phage display library. ATR-rAb was produced in mammalian HEK293 (F) cells. Among the four detection methods explored, the assay using AI-Nb-66 as a coating antigen and ATR-rAb as a detection reagent yielded a half maximal inhibitory concentration (IC50) of 1.66 ng mL-1 for ATR and a linear range of 0.35-8.73 ng mL-1. The cross-reactivity of the assay to ametryn was 64.24%, whereas that to terbutylazine was 38.20%. Surface plasmon resonance (SPR) analysis illustrated that these cross-reactive triazine compounds can bind to ATR-rAb to varying degrees at high concentrations; however, the binding/dissociation kinetic curves and the response values at the same concentration are different, which results in differences in cross-reactivity. Homology modeling and molecular docking revealed that the triazine ring is vital in recognizing triazine compounds. The proposed immunoassay exhibited acceptable recoveries of 84.40-105.36% for detecting fruit, vegetables, and black tea. In conclusion, this study highlights a new strategy for developing sustainable immunoassays for detecting trace pesticide contaminants.

Chromosome-level genome assembly and functional characterization of terpene synthases provide insights into the volatile terpenoid biosynthesis of Wurfbainia villosa.

Wurfbainia villosa is a well-known medicinal and edible plant that is widely cultivated in the Lingnan region of China. Its dried fruits (called Fructus Amomi) are broadly used in traditional Chinese medicine for curing gastrointestinal diseases and are rich in volatile terpenoids. Here, we report a high-quality chromosome-level genome assembly of W. villosa with a total size of approximately 2.80 Gb, 42 588 protein-coding genes, and a very high percentage of repetitive sequences (87.23%). Genome analysis showed that W. villosa likely experienced a recent whole-genome duplication event prior to the W. villosa-Zingiber officinale divergence (approximately 11 million years ago), and a recent burst of long terminal repeat insertions afterward. The W. villosa genome enabled the identification of 17 genes involved in the terpenoid skeleton biosynthesis pathway and 66 terpene synthase (TPS) genes. We found that tandem duplication events have an important contribution to the expansion of WvTPSs, which likely drove the production of volatile terpenoids. In addition, functional characterization of 18 WvTPSs, focusing on the TPS-a and TPS-b subfamilies, showed that most of these WvTPSs are multi-product TPS and are predominantly expressed in seeds. The present study provides insights into the genome evolution and the molecular basis of the volatile terpenoids diversity in W. villosa. The genome sequence also represents valuable resources for the functional gene research and molecular breeding of W. villosa.

Rhamnosyltransferases involved in the biosynthesis of flavone rutinosides in Chrysanthemum species.

Linarin (acacetin-7-O-rutinoside), isorhoifolin (apigenin-7-O-rutinoside), and diosmin (diosmetin-7-O-rutinoside) are chemically and structurally similar flavone rutinoside (FR) compounds found in Chrysanthemum L. (Anthemideae, Asteraceae) plants. However, their biosynthetic pathways remain largely unknown. In this study, we cloned and compared FRs and genes encoding rhamnosyltransferases (RhaTs) among eight accessions of Chrysanthemum polyploids. We also biochemically characterized RhaTs of Chrysanthemum plants and Citrus (Citrus sinensis and Citrus maxima). RhaTs from these two genera are substrate-promiscuous enzymes catalyzing the rhamnosylation of flavones, flavanones, and flavonols. Substrate specificity analysis revealed that Chrysanthemum 1,6RhaTs preferred flavone glucosides (e.g. acacetin-7-O-glucoside), whereas Cs1,6RhaT preferred flavanone glucosides. The nonsynonymous substitutions of RhaTs found in some cytotypes of diploids resulted in the loss of catalytic function. Phylogenetic analysis and specialized pathways responsible for the biosynthesis of major flavonoids in Chrysanthemum and Citrus revealed that rhamnosylation activity might share a common evolutionary origin. Overexpression of RhaT in hairy roots resulted in 13-, 2-, and 5-fold increases in linarin, isorhoifolin, and diosmin contents, respectively, indicating that RhaT is mainly involved in the biosynthesis of linarin. Our findings not only suggest that the substrate promiscuity of RhaTs contributes to the diversity of FRs in Chrysanthemum species but also shed light on the evolution of flavone and flavanone rutinosides in distant taxa.

Interaction of E2F3a and CASP8AP2 Regulates Histone Expression and Chemosensitivity of Leukemic Cells.

Low expression levels of E2F3a and caspase 8-associated protein 2 (CASP8AP2) are associated with poor outcomes in children with acute lymphoblastic leukemia. Our previous study showed that a combined assessment of E2F3a and CASP8AP2 expression was more accurate in predicting relapse in children with acute lymphoblastic leukemia. However, the underlying mechanism remains unclear. In this study, the interaction between E2F3a and CASP8AP2 and its role in the regulation of histone expression, cell proliferation, the cell cycle, and chemosensitivity were investigated. Exogenous E2F3a-GST was coprecipitated with CASP8AP2-FLAG in HEK-293T cells. E2F3a was colocalized with CASP8AP2-GFP in the nucleus. The replication-dependent histones H2A and H2B were significantly upregulated when E2F3a or CASP8AP2 was overexpressed in HEK-293T or 697 cells and downregulated by E2F3a or CASP8AP2 knockdown. E2F3a and CASP8AP2 could collaboratively enhance the transcriptional activity of HIST1H2AG and HIST1H2BK . Both CASP8AP2 and E2F3a are involved in S phase progression. E2F3a and CASP8AP2 also affected the sensitivity of leukemic cells to daunorubicin. Therefore, CASP8AP2 and E2F3a collaboratively regulated replication-dependent histone expression, cell cycle progression, and chemosensitivity of leukemic cells.

High-throughput screening and quantitative analysis of hidden ingredients in plant protection products by GC-MS/MS.

Hidden ingredients in plant protection products (PPPs) threaten public health, food trade, and the environment. In this study, we developed a high-throughput screening method of 639 hidden ingredients in PPPs using GC-MS/MS in multiple reaction monitoring mode. Results showed that the qualitative criteria of retention time (tR) shift and uncertainty of qualifier to quantifier ratio in the commercially available Shimadzu Smart Pesticides Database were set at < 0.17 min and < 30%, respectively, which could be used to tentatively identify compounds without standards. The limits of quantification were 0.01-0.05 mg/kg. A wide linear range of 10-1000 µg/L was observed with R2 ≥ 0.975. Recoveries from three types of PPP formulations were 62.08%- 126.3%, with relative standard deviations < 15.7%. Finally, this method was applied to screen and quantify hidden ingredients in 91 plant protection products (PPPs) samples collected from online sales in China. Only one hidden ingredient, dimethomorph (1.6 g/kg), was detected in the polyoxin formulation (15% wettable powder). The results will be helpful in assessing the potential risks of hidden ingredients in PPPs.

A Novel Fluorescent Sensor Based on Aptamer and qPCR for Determination of Glyphosate in Tap Water.

Glyphosate (GLYP) is a broad-spectrum, nonselective, organic phosphine postemergence herbicide registered for many food and nonfood fields. Herein, we developed a biosensor (Mbs@dsDNA) based on carboxylated modified magnetic beads incubated with NH2-polyA and then hybridized with polyT-glyphosate aptamer and complementary DNA. Afterwards, a quantitative detection method based on qPCR was established. When the glyphosate aptamer on Mbs@dsDNA specifically recognizes glyphosate, complementary DNA is released and then enters the qPCR signal amplification process. The linear range of the method was 0.6 µmol/L−30 mmol/L and the detection limit was set at 0.6 µmol/L. The recoveries in tap water ranged from 103.4 to 104.9% and the relative standard deviations (RSDs) were <1%. The aptamer proposed in this study has good potential for recognizing glyphosate. The detection method combined with qPCR might have good application prospects in detecting and supervising other pesticide residues.

[Comparison of catalytic functions and expression patterns of two pinene synthases from Wurfbainia villosa].

Wurfbainia villosa fruit is rich in volatile terpenoids, among which pinene is one of the main components and has anti-inflammatory, antibacterial, anti-tumor, and other pharmacological activities. This research group found that W. villosa fruits were rich in α-pinene by GC-MS, and terpene synthase(WvTPS63, formerly known as AvTPS1) with ß-pinene as the main product was cloned and identified, but α-pinene synthase had not been identified. In this study, based on the genome data of W. villosa, we screened and found WvTPS66 with highly similar sequences to WvTPS63, identified enzyme functions of WvTPS66 in vitro, and performed a comparative analysis of sequence, catalytic function, expression pattern, and promoter with WvTPS63. Multiple sequence alignment showed that the amino acid sequences of WvTPS63 and WvTPS66 were highly similar and the conservative motif of terpene synthase was almost identical. In vitro enzymatic experiments on catalytic functions showed that both could produce pinene, and the main product of WvTPS63 was ß-pinene, while that of WvTPS66 was α-pinene. Expression pattern analysis showed that WvTS63 was highly expressed in flowers, WvTPS66 was expressed in the whole plant, and the highest expression level was found in the pericarp, which indicated that it might be mainly responsible for the synthesis of α-pinene in fruits. In addition, promoter analysis revealed the presence of multiple regulatory elements related to stress response in the promoter regions of both genes. The findings of this study can provide a reference for the functional study of terpene synthase genes and new genetic elements for pinene biosynthesis.

US Shear-Wave Elastography Dispersion for Characterization of Chronic Liver Disease.

Background Little is known about the benefits of the use of dispersion slope (DS) as a viscosity-related parameter derived from two-dimensional (2D) shear-wave elastography (SWE) in the stratification of hepatic pathologic stages. Purpose To evaluate whether DS as an additional parameter can improve the diagnostic performance in detecting liver necroinflammation, fibrosis, and steatosis. Materials and Methods In this prospective study, consecutive participants with chronic liver disease who underwent liver biopsy and 2D SWE were recruited between July 2019 and September 2020. DS and liver stiffness (LS) measurements were obtained with use of a 2D SWE system immediately before biopsy. The biopsy specimens were assessed to obtain the scores of fibrosis, necroinflammation, and steatosis. Differences in the area under the receiver operating characteristic curve (AUC) were used to compare the diagnostic performance of DS, LS, and a combination of DS and LS. Results There were 159 participants evaluated (among them, 79 participants with chronic hepatitis B and 11 participants with nonalcoholic fatty liver disease). The distributions of DS values among various necroinflammatory activities (P = .02) and fibrosis stages (P < .001) were different. Moreover, DS was only associated with fibrosis after subgroup analysis based on the fibrosis stages and necroinflammatory activities (P < .001). The AUCs of DS in detecting clinically significant fibrosis (fibrosis stage ≥F2), cirrhosis (fibrosis stage of F4), and moderate to severe necroinflammatory activity (necroinflammatory activity ≥A2) were 0.72 (95% CI: 0.64, 0.79), 0.71 (95% CI: 0.63, 0.78), and 0.64 (95% CI: 0.55, 0.71), respectively. The differences of AUCs were not apparent for the DS and LS combination model after excluding DS (fibrosis stage ≥F2: 0.00 [95% CI: 0.00, 0.01], fibrosis stage of F4: -0.01 [95% CI: -0.02, 0.00], and necroinflammatory activity ≥A2: 0.00 [95% CI: 0.00, 0.01]). Conclusion The addition of dispersion slope derived from two-dimensional shear-wave elastography did not improve the diagnostic performance in detecting liver fibrosis, necroinflammation, or steatosis in patients with primarily viral hepatitis. ClinicalTrials.gov registration no.: NCT03777293 © RSNA, 2022 Online supplemental material is available for this article.

Isolation and characterization of AaZFP1, a C2H2 zinc finger protein that regulates the AaIPPI1 gene involved in artemisinin biosynthesis in Artemisia annua.

MAIN CONCLUSION: AaZFP1, a C2H2-type transcription factor, was found to bind the AGT-N1-10-AGT box of AaIPPI1pro and activate the expression of AaIPPI1 involved in artemisinin biosynthesis. Artemisinin, an endoperoxide sesquiterpene lactone, is a widely used antimalarial drug isolated from Artemisia annua L. Isopentenyl pyrophosphate isomerase (AaIPPI1) catalyzes the interconversion of isopentenyl diphosphate and dimethylallyl diphosphate and is the key gene involved in the biosynthesis of artemisinin. However, the AaIPPI1 gene regulation network remains largely unknown. Here, we isolated the AaIPPI1 promoter (AaIPPI1pro) and predicted that it contains cis-elements involved in stress responses, including the TGACG motif (a methyl jasmonate-responsive element), GARE motif (a gibberellin-responsive element), ABRE (an abscisic acid-responsive element), TC-rich repeats (a stress-responsive element), and the AGT-N1-10-AGT box, which is the binding site of Cys/His2 zinc finger protein (C2H2 ZFP). The C2H2 ZFP gene AaZFP1 was discovered by screening a cDNA library using AaIPPI1pro as bait in yeast. AaZFP1 contains two conserved C2H2 regions, a nuclear localization domain (B box), a Leu-rich domain (L box), and a conserved DLN sequence (DLN box) close to its C terminus. A subcellular localization assay indicated that AaZFP1 protein is localized in the nucleus and cytoplasm. An electrophoretic mobility shift assay demonstrated that AaZFP1 binds to the AGT-N1-10-AGT box of AaIPPI1pro. A dual-luciferase assay indicated that AaZFP1 enhanced the promoter activity of AaIPPI1 in vivo. Transient overexpression of AaZFP1 in A. annua increased the expression of AaIPPI1 and the content of artemisinin. Our data demonstrated that AaZFP1 functions as a transcriptional activator that regulates the expression of AaIPPI1 by directly binding to its promoter. The present study provides insights into the transcriptional regulation of genes involved in artemisinin biosynthesis in A. annua.

A competitive immunoassay for detecting triazophos based on fluorescent catalytic hairpin self-assembly.

A rapid detection method is introduced for residual trace levels of triazophos in water and agricultural products using an immunoassay based on catalytic hairpin self-assembly (CHA). The gold nanoparticle (AuNPs) surface was modified with triazophos antibody and sulfhydryl bio-barcode, and an immune competition reaction system was established between triazophos and its ovalbumin-hapten (OVA-hapten). The bio-barcode served as a catalyst to continuously induce the CHA reaction to achieve the dual signal amplification. The method does not rely on the participation of enzymes, and the addition of fluorescent materials in the last step avoids interfering factors, such as a fluorescence burst. The emitted fluorescence was detected at 489/521 nm excitation/emission wavelengths. The detection range of the developed method was 0.01-50 ng/mL for triazophos, and the limit of detection (LOD) was 0.0048 ng/mL. The developed method correlates well with the results obtained by LC-MS/MS, with satisfactory recovery and sensitivity. In sum, the designed method is reliable and provides a new approach to detect pesticide residues rapidly and quantitatively.

Combined inhibition of PD-1/PD-L1, Lag-3, and Tim-3 axes augments antitumor immunity in gastric cancer-T cell coculture models.

BACKGROUND: Immunotherapy targeting PD-1 provides a limited survival benefit in patients with unresectable advanced or recurrent gastric cancer (GC). Beside PD-L1, the expression of inhibitory ligands such as CEACAM-1 and LSECtin on GC cells account for this limitation. Here we assessed their expression and immune suppressive effect in GC patients. METHODS: Using multiplexed immunohistochemistry staining, we evaluated the distribution of different inhibitory ligands, including PD-L1, CEACAM-1, LSECtin, and MHC class II, in 365 GC patients. We analyzed their correlations and overall survival (OS) based on the expression of each inhibitory ligand and the independent prognostic factors that affect OS. Subsequently, we evaluated the additive effect of anti-PD-1 mAb or anti-PD-L1 mAb with/without anti-Lag-3 mAb with/without anti-Tim-3 mAb in cytotoxic assay using tumor-antigen specific CTL clones against GC cell lines. RESULTS: Co-expression of the inhibitory ligands for PD-1, Tim-3, and Lag-3 was observed in the largest proportion (34.7%). CEACAM-1, LSECtin, and MHC class II expression showed significant correlation with PD-L1 expression and OS. Multivariable analysis demonstrated that CEACAM-1 low is an independent prognostic factor. Furthermore, combining dual and triple ICIs yielded additive effect on cytotoxicity of CTL clones against each immune inhibitory ligand positive GC cell lines. CONCLUSIONS: Our findings suggested that the expression of inhibitory ligands for Tim-3 and Lag-3 on GC cells serve as potential biomarkers to predict the response to anti-PD-1 therapy and the combinatorial immunotherapy with ICIs targeting for PD-1, Tim-3, and Lag-3 has a therapeutic potential for GC patients.

Dissipation and risk assessment of forchlorfenuron and its major metabolites in oriental melon under greenhouse cultivation.

Forchlorfenuron is a widely used plant growth regulator. The uptake of forchlorfenuron and its major metabolites poses a potential risk for human health. However, little is known about the dissipation of forchlorfenuron and its major metabolites in agricultural food. In this study, the metabolite 4-hydroxyphenyl-forchlorfenuron was first identified in oriental melon, which exhibited the highest level of residues of 4.42-5.12 µg/kg on the 4-7th days after application. Forchlorfenuron was found to be dissipated rapidly in melon at the recommended application rates, with half-lives ranging from 1.20 to 1.33 days. The rate of dissipation of 4-hydroxyphenyl-forchlorfenuron was greater than that of metabolism from forchlorfenuron in the oriental melon. However, the other metabolite, 3-hydroxyphenyl-forchlorfenuron, was not detected in oriental melon. The risk assessment showed that the acute and chronic dietary exposure risks of forchlorfenuron in oriental melon were 0.0011-0.0037% and 0.06-0.12%, respectively, suggesting little health risk to Chinese consumers.

Orf165 is associated with cytoplasmic male sterility in pepper.

Cytoplasmic male sterility (CMS) is a maternally inherited trait that derives from the inability to produce functional pollen in higher plants. CMS results from recombination of the mitochondrial genome. However, understanding of the molecular mechanism of CMS in pepper is limited. In this study, comparative transcriptomic analyses were performed using a near-isogenic CMS line 14A (CMS-14A) and a maintainer line 14B (ML-14B) as experimental materials. A total of 17,349 differentially expressed genes were detected between CMS-14A and ML-14B at the PMC meiosis stage. Among them, six unigenes associated with CMS and 108 unigenes involved in energy metabolism were identified. The gene orf165 was found in CMS-14A. When orf165 was introduced into ML-14B, almost 30% of transgenic plants were CMS. In addition, orf165 expression in transgenic CMS plants resulted in abnormal function of some genes involved in energy metabolism. When orf165 in transgenic CMS plant was silenced, the resulted orf165-silenced plant was male fertile and the expression patterns of some genes associated with energy metabolism were similar to ML-14B. Thus, we confirmed that orf165 influenced CMS in pepper.

Levels and characteristics of polychlorinated biphenyls in surface sediments of the Chaobai river, a source of drinking water for Beijing, China.

We collected surface sediments from the Chaobai river, the dominant source of drinking water for Beijing, China, to assess the status of contamination by polychlorinated biphenyls and evaluate their sources. Total concentrations of polychlorinated biphenyls in the sediments ranged from 0.125 to 70.6 ng/g dry weight and correlated with the locations relating to painting operation such as printing factories and construction material markets. Dioxin-like polychlorinated biphenyls were present and corresponded with constituents of commercial polychlorinated biphenyl mixtures. Principal component analysis indicated two dominant sources of polychlorinated biphenyls in the sediments-deposition from airborne emissions and point-source pollution from factories. An ecological risk assessment concluded that there was only slight polychlorinated biphenyl pollution in the sediments of the Chaobai river, which was not likely to induce adverse biological effects. Our findings provide information for polychlorinated biphenyl risk assessment and recognition of the dominant sources of these compounds in drinking water in China.

A "half" core-shell magnetic nanohybrid composed of zeolitic imidazolate framework and graphitic carbon nitride for magnetic solid-phase extraction of sulfonylurea herbicides from water samples followed by LC-MS/MS detection.

A "half" core-shell g-C3N4/Fe3O4@ZIF-8 nanohybrid, in which Fe3O4 and zeolite imidazolate framework-8 (ZIF-8) constructed the core-shell structure, was successfully fabricated via a versatile in situ growth strategy. This nanohybrid was employed for simultaneous magnetic solid-phase extraction (MSPE) of trace levels of fifteen target sulfonylurea herbicides (SUHs) in environmental water samples followed by LC-MS/MS detection. C3N4 nanosheets were first prepared by liquid exfoliation of bulk g-C3N4, after which Fe3O4 nanoparticles were uniformly deposited onto the surface of C3N4 nanosheets, and ZIF-8 nanoparticles were grown on the surface of g-C3N4/Fe3O4 by anchoring Zn2+ on g-C3N4/Fe3O4. Owing to the synergistic effect, the hybridization of C3N4 and ZIF-8 endowed the nanohybrid with higher multi-target adsorption ability for SUHs compared to pure C3N4 or ZIF-8. The separation as well as the enrichment processes were facilitated using Fe3O4 as a magnetic core. The influence of various parameters on MSPE efficiency, including adsorbent dosage, extraction time, solution pH, and desorption solvent and its volume, was investigated in detail. Under optimal conditions, the MSPE coupled with LC-MS/MS exhibited good linearity ranging from 0.5 to 100 µg L-1 with correlation coefficients (R2) ≥ 0.9919, high sensitivity with low limits of detection (LODs) of 0.005-0.141 µg L-1 and satisfactory recoveries of 67.4-105.5% with relative standard deviations (RSDs) < 9.8%. These results indicate that this method is reliable for the determination of SUHs in different matrices and the in situ growth strategy is a promising approach for constructing effective adsorbents. Graphical abstract Schematic representation of a "half" core-shell magnetic nanohybrid composed of zeolitic imidazolate framework (ZIF-8) and graphitic carbon nitride (g-C3N4) for magnetic solid-phase extraction (MSPE) of trace level determination of fifteen sulfonylurea herbicides (SUHs) in environmental water samples using LC-MS/MS detection.

Flower transcriptome dynamics during nectary development in pepper (Capsicum annuum L.).

The measurement of gene expression can provide important information about gene function and the molecular basis for developmental processes. We analyzed the transcriptomes at three different developmental stages of pepper flower [sporogenous cell division, stage (B1); pollen mother cell meiosis, stage (B2); and open flower (B3)]. In the cDNA libraries for B1, B2, and B3: 82718, 77061, and 91491 unigenes were assembled, respectively. A total of 34,445 unigene sequences and 128 pathways were annotated by KEGG pathway analysis. Several genes associated with nectar biosynthesis and nectary development were identified, and 8,955, 12,182, and 23,667 DEGs were identified in the B2 vs B1, B3 vs B1, and B3 vs. B2 comparisons. DEGs were involved in various metabolic processes, including flower development, nectar biosynthesis, and nectary development. According to the RNA-seq data, all 13 selected DEGs showed similar expression patterns after q-PCR analysis. Sucrose-phosphatase, galactinol-sucrose galactosyltransferase, and sucrose synthase played very important roles in nectar biosynthesis, and CRABS CLAW could potentially be involved in mediating nectary development. A significant number of simple sequence repeat and single nucleotide polymorphism markers were predicted in the Capsicum annuum sequences. The new results provide valuable genetic information about flower development in pepper.

Microbial communities across nearshore to offshore coastal transects are primarily shaped by distance and temperature.

Recent studies have focused on linking marine microbial communities with environmental factors, yet, relatively little is known about the drivers of microbial community patterns across the complex gradients from the nearshore to open ocean. Here, we examine microbial dynamics in 15 five-station transects beginning at the estuarine Piver's Island Coastal Observatory (PICO) time-series site and continuing 87 km across the continental shelf to the oligotrophic waters of the Sargasso Sea. 16S rRNA gene libraries reveal strong clustering by sampling site with distinct nearshore, continental shelf and offshore oceanic communities. Water temperature and distance from shore (which serves as a proxy for gradients in factors such as productivity, terrestrial input and nutrients) both most influence community composition. However, at the phylotype level, modelling shows the distribution of some taxa is linked to temperature, others to distance from shore and some by both factors, highlighting that taxa with distinct environmental preferences underlie apparent clustering by station. Thus, continental margins contain microbial communities that are distinct from those of either the nearshore or the offshore environments and contain mixtures of phylotypes with nearshore or offshore preferences rather than those unique to the shelf environment.