Recent development of gold nanochips in biosensing and biodiagnosis sensibilization strategies in vitro based on SPR, SERS and FRET optical properties.

Gold nanomaterials have become attractive nanomaterials for biomedical research due to their unique physical and chemical properties, and nanochips are designed to manufacture high-quality substrates for loading gold nanoparticles (GNPs) to achieve specific and selective detection. By utilizing multiple optical properties of different gold nanostructures, the sensitivity, specificity, speed, contrast, resolution, and other performance of biosensing and biological diagnosis can be significantly improved. This paper summarized the sensitivity enhancement strategies of optical biosensing techniques based on the three main optical properties of gold nanomaterials: surface plasmon resonance (SPR), surface-enhanced Raman scattering (SERS) and fluorescence resonance energy transfer (FRET). The aim is to comprehensively review the development direction of in vitro diagnostics (IVDs) from two aspects: detection strategies and modification of gold nanomaterials. In addition, some opportunities and challenges that gold-based IVDs may encounter at present or in the future are also mentioned in this paper. In summary, this paper can enlighten readers with feasible strategies for manufacturing potential gold-based nanobiosensors.

Optimized analysis for related substances in spiramycin based on high performance liquid chromatography with hybrid particle column and characterization of its impurities by single heartcut two-dimensional liquid chromatography coupled with quadrupole time-of-flight mass spectrometer.

This article described the development and validation of a method for spiramycin related substances based on hybrid particle column. The chromatographic conditions were as follows: water - 0.2 mol/L dipotassium hydrogen phosphate (the pH value adjusted to 9.5 using a 1 mol/L KOH solution) - acetonitrile - methanol (10: 60: 28.5: 1.5, v/v/v/v) as mobile phase A, water - 0.2 mol/L dipotassium hydrogen phosphate (pH 9.5) - acetonitrile - methanol (10: 30: 57: 3, v/v/v/v) as mobile phase B and gradient elution was performed. Compared with previous analytical methods, this method has strong specificity, excellent sensitivity and stability, which could be used for the daily testing of related substances of spiramycin. Furthermore, impurities above 0.1 % were characterized using two-dimensional liquid chromatography coupled with quadrupole time-of-flight mass spectrometer (2D LC-QTOF-MS/MS) and there were 6 impurities reported for the first time.

Synthesis of Novel Propionamide-Methylpyrazole Carboxylates as Herbicidal Candidates.

Transketolase (TKL; EC 2.2.1.1) is a highly promising potential target for herbicidal applications. To identify novel TKL inhibitors, we designed and synthesized a series of 3-oxopropionamide-1-methylpyrazole carboxylate analogues and assessed their herbicidal activities. Ethyl 3-((1-((2,4-dichlorophenyl)amino)-1-oxopropan-2-yl)oxy)-1-methyl-1H-pyrazole-5-carboxylate (D15) and ethyl 1-methyl-3-((1-oxo-1-((thiophen-2-ylmethyl)amino)propan-2-yl)oxy)-1H-pyrazole-5-carboxylate (D20) exhibited superior growth inhibition activities against both the root and stem of Amaranthus retroflexus (A. retroflexus) compared to nicosulfuron and mesotrione. Additionally, D15 achieved an inhibition rate of more than 90% against the roots and stems of Digitaria sanguinalis (D. sanguinalis), outperforming the four control agents at a concentration of 200 mg/L using the small cup method. In the pre-emergence herbicidal activity test, D15 effectively inhibited D. sanguinalis by more than 90% at 150 g ai/ha, surpassing the efficacy of the control, mesotrione. Conversely, in the postemergence herbicidal activity test, D20 exhibited efficient inhibition of A. retroflexus by more than 90% at 150 g ai/ha, outperforming the control agents nicosulfuron, mesotrione, and metamifop. The results of the TKL enzyme activity test showed that the IC50 values of compounds D15 and D20 were 0.384 and 0.655 mg/L, respectively, which were close to those of the control agents. Furthermore, molecular docking and molecular dynamics simulation studies revealed that D15 and D20 interacted favorably with the TKL of Setaria viridis. Such findings highlight the promising potential of D15 and D20 as lead TKL inhibitors for the optimization of new herbicides.

Activation patterns and electrophysiologic characteristics of Marshall bundle-related left atrial tachycardias after atrial fibrillation ablation.

BACKGROUND: Epicardial Marshall bundles (MBs) are frequently used in left atrial tachycardias (LATs) after atrial fibrillation (AF) ablation with pulmonary vein isolation and substrate modification. OBJECTIVE: This study sought to classify different activation patterns of MB-mediated LATs and the corresponding electrophysiologic characteristics. METHODS: From 2019 to 2021, 28 cases of atrial tachycardias after AF ablation were diagnosed as MB-mediated LATs by ultrahigh-density mapping and entrainment. Cannulation and mapping in the vein of Marshall (VOM) and epicardial mapping in the MB region were also performed in selected cases to further prove the mechanism. RESULTS: Three activation patterns were identified with a critical isthmus through the MB: perimitral macroreentry (perimitral LAT; n = 20 [71.4%]); left atrial appendage-related reentry (n = 5 [17.9%]); and left pulmonary vein-related reentry (n = 3 [10.7%]). In 18 patients, a characteristic triple potential observed along the previously endocardial left atrial ridge block line was composed of near-field double potentials and far-field MB potential. These findings were further delineated in 24 patients with either cannulation in the VOM (19 patients) or epicardial mapping (5 patients). Ethanol infusion of the VOM resulted in atrial tachycardia termination in 20 of 28 patients. CONCLUSION: Different types of MB-mediated LATs after AF ablation could be identified by ultrahigh-density mapping. Ethanol infusion within the VOM was effective in eliminating these tachycardias.

Planting halophytes increases the rhizosphere ecosystem multifunctionality via reducing soil salinity.

Soil salinization poses a significant global challenge, exerting adverse effects on both agriculture and ecosystems. Planting halophytes has the potential ability to improve saline-alkali land and enhance ecosystem multifunctionality (EMF). However, it remains unclear which halophytes are effective in improving saline-alkali land and what impact they have on the rhizosphere microbial communities and EMF. In this study, we evaluated the Na+ absorption capability of five halophytes (Grubovia dasyphylla, Halogeton glomeratus, Suaeda salsa, Bassia scoparia, and Reaumuria songarica) and assessed their rhizosphere microbial communities and EMF. The results showed that S. salsa possessed the highest shoot (3.13 mmol g-1) and root (0.92 mmol g-1) Na+ content, and its soil Na+ absorption, along with B. scoparia, was significantly higher than that of other plants. The soil pH, salinity, and Na+ content of the halophyte rhizospheres decreased by 6.21%, 23.49%, and 64.29%, respectively, when compared to the bulk soil. Extracellular enzymes in the halophyte rhizosphere soil, including α-glucosidase, ß-glucosidase, ß-1,4-N-acetyl-glucosaminidase, neutral phosphatase, and alkaline phosphatase, increased by 70.1%, 78.4%, 38.5%, 79.1%, and 64.9%, respectively. Furthermore, the halophyte rhizosphere exhibited higher network complexity of bacteria and fungi and EMF than bulk soil. The relative abundance of the dominant phyla Proteobacteria, Firmicutes, and Ascomycota in the halophyte rhizosphere soil increased by 9.4%, 8.3%, and 22.25%, respectively, and showed higher microbial network complexity compared to the bulk soil. Additionally, keystone taxa, including Muricauda, Nocardioides, and Pontibacter, were identified with notable effects on EMF. This study confirmed that euhalophytes are the best choice for saline-alkali land restoration. These findings provided a theoretical basis for the sustainable use of saline-alkali cultivated land.

A Sb(III)-specific efflux transporter from Ensifer adhaerens E-60.

Antimony is pervasive environmental toxic substance, and numerous genes encoding mechanisms to resist, transform and extrude the toxic metalloid antimony have been discovered in various microorganisms. Here we identified a major facilitator superfamily (MFS) transporter, AntB, on the chromosome of the arsenite-oxidizing bacterium Ensifer adhaerens E-60 that confers resistance to Sb(III) and Sb(V). The antB gene is adjacent to gene encoding a LysR family transcriptional regulator termed LysRars, which is an As(III)/Sb(III)-responsive transcriptional repressor that is predicted to control expression of antB. Similar antB and lysRars genes are found in related arsenic-resistant bacteria, especially strains of Ensifer adhaerens, and the lysRars gene adjacent to antB encodes a member of a divergent subgroup of putative LysR-type regulators. Closely related AntB and LysRars orthologs contain three conserved cysteine residues, which are Cys17, Cys99, and Cys350 in AntB and Cys81, Cys289 and Cys294 in LysRars, respectively. Expression of antB is induced by As(III), Sb(III), Sb(V) and Rox(III) (4-hydroxy-3-nitrophenyl arsenite). Heterologous expression of antB in E. coli AW3110 (Δars) conferred resistance to Sb(III) and Sb(V) and reduced the intracellular concentration of Sb(III). The discovery of the Sb(III) efflux transporter AntB enriches our knowledge of the role of the efflux transporter in the antimony biogeochemical cycle.

Exploring patients with COPD self-care behaviours and self-efficacy and their interconnections: A network analysis.

AIM: The aim of this study was to investigate self-care behaviours of patients with chronic obstructive pulmonary disease (COPD), understand their complex interconnections and identify key behaviours influencing self-care and self-efficacy. DESIGN: An observational, cross-sectional study design. SETTING(S): The outpatient department of two tertiary hospital. METHODS: A convenience sample of patients with a diagnosis of COPD were included (n = 222). Self-care behaviours were assessed using the Chinese version of self-care of chronic obstructive pulmonary disease inventory based on the Middle-Range Theory of Self-Care of Chronic Illness. Patient self-care efficacy was evaluated using Chinese version of Self-Care Self-Efficacy Scale in Chronic Obstructive Pulmonary Disease. Employing network analysis, associations between behaviours (nodes) and their interrelationships (edges) were deciphered. The study was reported following the STROBE checklist. RESULTS: Among the spectrum of self-care behaviours, patients exhibited the most pronounced deficiencies in behaviours directed to enhancing breathing, monitoring extra-respiratory symptoms and problem-solving. Within the network, the most central emerging behaviour was the modification of prescribed therapy at the worsening of symptoms, as suggested by healthcare providers, which drives all self-care behaviours. The confidence in being able to do something to relieve symptoms, despite difficulties, was a bridging activator of self-care. The network structure underscored the prominence of self-care self-efficacy in driving self-care maintenance, monitoring, and management behaviours. CONCLUSIONS: Education programs for COPD should prioritise enhancing breathing, symptom monitoring and problem-solving skills. The crucial self-care behaviour in COPD involves adjusting treatments in response to symptom changes. Patient confidence in symptom alleviation acts as a catalyst for self-care engagement. Targeted assessments addressing these aspects could enhance educational interventions, ultimately improving COPD patient outcomes. REGISTRATION: This study has been registered in the Chinese Clinical Trials Registry (registration number: ChiCTR2200059764; registration date: 11 May 2022).

Characterization of ribostamycin and its impurities using a nano-quantity analyte detector: Systematic comparison of performance among three different aerosol detectors.

Characterization of aminoglycoside antibiotics like ribostamycin is important due to the complex composition and common toxic impurities. Aerosol detectors are often employed for determination of these non-absorbent analytes. In this work, a robust and cost-effective method was developed for simultaneous detection of ribostamycin and its related substances using high-performance liquid chromatography (HPLC) with a relative new aerosol detector named nano-quantity analyte detector (NQAD). With the introduction of less toxic but more compatible ion-pairs pentafluoropropionic acid (PFPA) and trifluoroacetic acid (TFA) in the eluent, an optimized separation effect was achieved. Compared with the other two aerosol detectors namely ELSD (evaporative light scattering detector) and CAD (charged aerosol detector), method verification and quantitative detection results revealed that NQAD had higher sensitivity than ELSD with a 0.8 µg/mL limit of detection, as well as wider linear range (from 2 µg/mL to 1000 µg/mL) than both CAD (from 2 µg/mL to 200 µg/mL) and ELSD (from 8 µg/mL to 200 µg/mL) detector. The performance of NQAD helped to realize detection of ribostamycin and its impurities with significant concentration differences in a single run. With a cation suppressor to eliminate the ion-suppression caused by the ion-pairs in the eluent, the structure of nine impurities in ribostamycin sample was characterized by liquid chromatography-mass spectrum (LC-MS). Both external standard and area normalization calculation were investigated, and NQAD obtained more accurate results due to its full-range linear response-to-concentration relationship, providing an alternative for routine quality control of multi analyte systems.

Discrimination of polysorbate 20 by high-performance liquid chromatography-charged aerosol detection and characterization for components by expanding compound database and library.

Analyzing polysorbate 20 (PS20) composition and the impact of each component on stability and safety is crucial due to formulation variations and individual tolerance. The similar structures and polarities of PS20 components make accurate separation, identification, and quantification challenging. In this work, a high-resolution quantitative method was developed using single-dimensional high-performance liquid chromatography (HPLC) with charged aerosol detection (CAD) to separate 18 key components with multiple esters. The separated components were characterized by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) with an identical gradient as the HPLC-CAD analysis. The polysorbate compound database and library were expanded over 7-time compared to the commercial database. The method investigated differences in PS20 samples from various origins and grades for different dosage forms to evaluate the composition-process relationship. UHPLC-Q-TOF-MS identified 1329 to 1511 compounds in 4 batches of PS20 from different sources. The method observed the impact of 4 degradation conditions on peak components, identifying stable components and their tendencies to change. HPLC-CAD and UHPLC-Q-TOF-MS results provided insights into fingerprint differences, distinguishing quasi products.

Discovery of novel Propionamide-Pyrazole-Carboxylates as Transketolase-inhibiting herbicidal candidates.

BACKGROUND: Transketolase (TKL, EC 2.2.1.1) is a key enzyme in the pentose phosphate pathway and Calvin cycle, and is expected to act as a herbicidal site-of-action. On the basis of TKL, we designed and synthesized a series of 1-oxy-propionamide-pyrazole-3-carboxylate analogues and evaluated their herbicidal activities. RESULTS: Methyl 1-methyl-5-((1-oxo-1-((4-(trifluoromethyl)phenyl)amino)propan-2-yl)oxy)-1H-pyrazole-3-carboxylate (C23) and methyl 1-methyl-5-((1-oxo-1-((perfluorophenyl)amino)propan-2-yl)oxy)-1H-pyrazole-3-carboxylate (C33) were found to provide better growth-inhibition activities against Digitaria sanguinalis root than those of nicosulfuron, mesotrione and pretilachlor at 200 mg L-1 using the small-cup method. These compounds were also identified as promising compounds in pre-emergence and postemergence herbicidal-activity experiments, with relatively good inhibitory effects toward Amaranthus retroflexus and D. sanguinalis at 150 g ai ha-1. In addition, enzyme inhibition assays and molecular docking studies revealed that C23 and C33 interact favourably with SvTKL (Setaria viridis TKL). CONCLUSION: C23 and C33 are promising lead TKL inhibitors for the optimization of new herbicides. © 2024 Society of Chemical Industry.

Physiology and transcriptomic analysis revealed the mechanism of silicon promoting cadmium accumulation in Sedum alfredii Hance.

Silicon (Si) effectively promote the yield of many crops, mainly due to its ability to enhance plants resistance to stress. However, how Si helps hyperaccumulators to extract Cadmium (Cd) from soil has remained unclear. In this study, Sedum alfredii Hance (S. alfredii) was used as material to study how exogenous Si affected biomass, Cd accumulation, antioxidation, cell ultrastructure, subcellular distribution and changes in gene expression after Cd exposure. The study has shown that as Si concentration increases (1, 2 mM), the shoot biomass of plants increased by 33.1%-63.6%, the Cd accumulation increased by 31.9%-96.6%, and the chlorophyll, carotenoid content, photosynthetic gas exchange parameters significantly increased. Si reduced Pro and MDA, promoted the concentrations of SOD, CAT and POD to reduce antioxidant stress damage. In addition, Si promoted GSH and PC to chelate Cd in vacuoles, repaired damaged cell ultrastructure, improved the fixation of Cd and cell wall (especially in pectin), and reduced the toxic effects of Cd. Transcriptome analysis found that genes encoding Cd detoxification, Cd absorption and transport were up-regulated by Si supplying, including photosynthetic pathways (PSB, LHCB, PSA), antioxidant defense systems (CAT, APX, CSD, RBOH), cell wall biosynthesis such as pectinesterase (PME), chelation (GST, MT, NAS, GR), Cd absorption (Nramp3, Nramp5, ZNT) and Cd transport (HMA, PCR). Our result revealed the tentative mechanism of Si promotes Cd accumulation and enhances Cd tolerance in S. alfredii, and thereby provides a solid theoretical support for the practical use of Si fertilizer in phytoextraction.

Salicylic Acid's impact on Sedum alfredii growth and cadmium tolerance: Comparative physiological, transcriptomic, and metabolomic study.

With the acceleration of industrialization, Cd pollution has emerged as a major threat to soil ecosystem health and food safety. Hyperaccumulating plants like Sedum alfredii Hance are considered to be used as part of an effective strategy for the ecological remediation of Cd polluted soils. This study delved deeply into the physiological, transcriptomic, and metabolomic responses of S. alfredii under cadmium (Cd) stress when treated with exogenous salicylic acid (SA). We found that SA notably enhanced the growth of S. alfredii and thereby increased absorption and accumulation of Cd, effectively alleviating the oxidative stress caused by Cd through upregulation of the antioxidant system. Transcriptomic and metabolomic data further unveiled the influence of SA on photosynthesis, antioxidant defensive mechanisms, and metal absorption enrichment pathways. Notably, the interactions between SA and other plant hormones, especially IAA and JA, played a central role in these processes. These findings offer us a comprehensive perspective on understanding how to enhance the growth and heavy metal absorption capabilities of hyperaccumulator plants by regulating plant hormones, providing invaluable strategies for future environmental remediation efforts.

Plastic footprint deteriorates dryland carbon footprint across soil-plant-atmosphere continuum.

Plastic fragments are widely found in the soil profile of terrestrial ecosystems, forming plastic footprint and posing increasing threat to soil functionality and carbon (C) footprint. It is unclear how plastic footprint affects C cycling, and in particularly permanent C sequestration. Integrated field observations (including 13C labelling) were made using polyethylene and polylactic acid plastic fragments (low-, medium- and high-concentrations as intensifying footprint) landfilling in soil, to track C flow along soil-plant-atmosphere continuum (SPAC). The result indicated that increased plastic fragments substantially reduced photosynthetic C assimilation (p < 0.05), regardless of fragment degradability. Besides reducing C sink strength, relative intensity of C emission increased significantly, displaying elevated C source. Moreover, root C fixation declined significantly from 21.95 to 19.2 mg m-2, and simultaneously root length density, root weight density, specific root length and root diameter and surface area were clearly reduced. Similar trends were observed in the two types of plastic fragments (p > 0.05). Particularly, soil aggregate stability was significantly lowered as affected by plastic fragments, which accelerated the decomposition rate of newly sequestered C (p < 0.05). More importantly, net C rhizodeposition declined averagely from 39.77 to 29.41 mg m-2, which directly led to significant decline of permanent C sequestration in soil. Therefore, increasing plastic footprint considerably worsened C footprint regardless of polythene and biodegradable fragments. The findings unveiled the serious effects of plastic residues on permanent C sequestration across SPAC, implying that current C assessment methods clearly overlook plastic footprint and their global impact effects.

Electrophysiologic mechanism and ablation strategy for macroreentrant biatrial tachycardias after Cox-maze procedures.

BACKGROUND: Different types of recurrent atrial tachycardia (AT) after Cox-maze procedures have been reported, whereas biatrial tachycardia (BiAT) has not been systematically analyzed. OBJECTIVE: In this study, we retrospectively investigated the electrophysiologic characteristics of BiAT after Cox-maze procedures by use of an ultrahigh-density mapping system. METHODS: Of a consecutive 76 patients who underwent catheter ablation of AT after Cox-maze procedures, 12 BiATs were identified. High-density activation mapping was performed in both the left atrium and right atrium in combination with entrainment pacing to confirm the circuit. RESULTS: We classified these BiATs into 2 groups. In group 1 (7 patients), the bidirectional block of maze linear lesions to prevent the macroreentrant AT was achieved; the posterior interatrial connections were involved in the circuit. In group 2 (5 patients), the bidirectional block of maze linear lesions was not blocked, and the most common gap was located at the end of the linear lesion near the annulus. In group 1, all the ATs were terminated by targeting the corresponding left atrium end of the posterior interatrial connections. In group 2, the ATs were terminated by targeting the gap near the annulus. CONCLUSION: The optimal ablation strategy for BiATs after the maze procedure should be based on detailed demonstration of the circuit by high-density mapping.

Discovery of Novel Pyrazole Acyl Thiourea Skeleton Analogue as Potential Herbicide Candidates.

To discover novel transketolase (TKL, EC 2.2.1.1) inhibitors with potential herbicidal applications, a series of pyrazole acyl thiourea derivatives were designed based on a previously obtained pyrazolamide acyl lead compound, employing a scaffold hopping strategy. The compounds were synthesized, their structures were characterized, and they were evaluated for herbicidal activities. The results indicate that 7a exhibited exceptional herbicidal activity against Digitaria sanguinalis and Amaranthus retroflexus at a dosage of 90 g ai/ha, using the foliar spray method in a greenhouse. This performance is comparable to that of commercial products, such as nicosulfuron and mesotrione. Moreover, 7a showed moderate growth inhibitory activity against the young root and stem of A. retroflexus at 200 mg/L in the small cup method, similar to that of nicosulfuron and mesotrione. Subsequent mode-of-action verification experiments revealed that 7a and 7e inhibited Setaria viridis TKL (SvTKL) enzyme activity, with IC50 values of 0.740 and 0.474 mg/L, respectively. Furthermore, they exhibited inhibitory effects on the Brassica napus acetohydroxyacid synthase enzyme activity. Molecular docking predicted potential interactions between these (7a and 7e) and SvTKL. A greenhouse experiment demonstrated that 7a exhibited favorable crop safety at 150 g ai/ha. Therefore, 7a is a promising herbicidal candidate that is worthy of further development.

Low Pneumoperitoneum Pressure Reduces Gas Embolism During Laparoscopic Liver Resection: A Randomized Controlled Trial.

OBJECTIVE: To compare the effect of low and standard pneumoperitoneal pressure (PP) on the occurrence of gas embolism during laparoscopic liver resection (LLR). BACKGROUND: LLR has an increased risk of gas embolism. Although animal studies have shown that low PP reduces the occurrence of gas embolism, clinical evidence is lacking. METHODS: This parallel, dual-arm, double-blind, randomized controlled trial included 141 patients undergoing elective LLR. Patients were randomized into standard ("S," 15 mm Hg; n = 70) or low ("L," 10 mm Hg; n = 71) PP groups. Severe gas embolism (≥ grade 3, based on the Schmandra microbubble method) was detected using transesophageal echocardiography and recorded as the primary outcome. Intraoperative vital signs and postoperative recovery profiles were also evaluated. RESULTS: Fewer severe gas embolism cases (n = 29, 40.8% vs n = 47, 67.1%, P = 0.003), fewer abrupt decreases in end-tidal carbon dioxide partial pressure, shorter severe gas embolism duration, less peripheral oxygen saturation reduction, and fewer increases in heart rate and lactate during gas embolization episodes was found in group L than in group S. Moreover, a higher arterial partial pressure of oxygen and peripheral oxygen saturation were observed, and fewer fluids and vasoactive drugs were administered in group L than in group S. In both groups, the distensibility index of the inferior vena cava negatively correlated with central venous pressure throughout LLR, and a comparable quality of recovery was observed. CONCLUSIONS: Low PP reduced the incidence and duration of severe gas embolism and achieved steadier hemodynamics and vital signs during LLR. Therefore, a low PP strategy can be considered a valuable choice for the future LLR.

Design, Synthesis, and Herbicidal Activity of Pyrazole Amide Derivatives as Potential Transketolase Inhibitors.

The design and synthesis of new herbicidal active compounds based on a new target are of great significance for the development of new herbicides. Transketolase (TK) plays a key role in the Calvin cycle of plant photosynthesis and has been confirmed as a potential candidate target to develop and discover new herbicides. To obtain compounds with ultraefficient targeting of TK, a series of pyrazole amide derivatives were designed and synthesized through structural optimization for lead compound 4u based on TK as the new target. The bioassay results showed that compounds 6ba and 6bj displayed a highly inhibitory effect with the root inhibition of about 90% against Digitaria sanguinalis (DS) and 80% against Amaranthus retroflexus (AR) and Setaria viridis (SV) by the small cup method, which was better than the positive control mesotrione and nicosulfuron. Furthermore, compounds 6ba and 6bj exhibited an excellent inhibitory effect with the inhibition of about 80% (against DS) and over 80% (against SV) at the dosage of 150 g of active ingredient/ha by the foliar spray method. The TK enzyme activity inhibition test showed that the inhibition effect of target compounds against TK was consistent with the results of herbicidal activities. Also, molecular docking analysis showed that compounds 6ba and 6bj went deep into the active cavity of TK, bound to TK by a strong interaction, and might act on the enzyme TK. Above of all, compounds 6ba and 6bj are promising herbicide lead compounds targeting TK. Hence, they could be developed into more efficient herbicides by further structural optimization.

The salt-tolerance of perennial ryegrass is linked with root exudate profiles and microflora recruitment.

Salinity poses a significant threat to plant growth and development. The root microbiota plays a key role in plant adaptation to saline environments. Nevertheless, it remains poorly understood whether and how perennial grass plants accumulate specific root-derived bacteria when exposed to salinity. Here, we systematically analyzed the composition and variation of rhizosphere and endophytic bacteria, as well as root exudates in perennial ryegrass differing in salt tolerance grown in unsterilized soils with and without salt. Both salt-sensitive (P1) and salt-tolerant (P2) perennial ryegrass genotypes grew better in unsterilized soils compared to sterilized soils under salt stress. The rhizosphere and endophytic bacteria of both P1 and P2 had lower alpha-diversity under salt treatment compared to control. The reduction of alpha-diversity was more pronounced for P1 than for P2. The specific root-derived bacteria, particularly the genus Pseudomonas, were enriched in rhizosphere and endophytic bacteria under salt stress. Changes in bacterial functionality induced by salt stress differed in P1 and P2. Additionally, more root exudates were altered under salt stress in P2 than in P1. The content of important root exudates, mainly including phenylpropanoids, benzenoids, organic acids, had a significantly positive correlation with the abundance of rhizosphere and endophytic bacteria under salt stress. The results indicate that the interactions between root-derived bacteria and root exudates are crucial for the salt tolerance of perennial ryegrass, which provides a potential strategy to manipulate root microbiome for improved stress tolerance of perennial grass species.

Development of an immunoassay based on a specific antibody for the detection of diphenyl ether herbicide fomesafen.

Fomesafen belongs to the diphenyl ether herbicide, and is widely used in the control of broadleaf weeds in crop fields due to its high efficiency and good selectivity. The residual of fomesafen in soil has a toxic effect on subsequent sensitive crops and the microbial community structure because of its long residual period. Therefore, an efficient method for detecting fomesafen is critical to guide the correct and reasonable use of this herbicide. Rapid and sensitive immunoassay methods for fomesafen is unavailable due to the lack of specific antibody. In this study, a specific antibody for fomesafen was generated based on rational design of haptens and a sensitive immunoassay method was established. The half maximal inhibitory concentration (IC50) of the immunoassay was 39 ng/mL with a linear range (IC10-90) of 1.92-779.8 ng/mL. In addition, the developed assay had a good correlation with the standard UPLC-MS/MS both in the spike-recovery studies and in the detection of real soil samples. Overall, the developed indirect competitive enzyme immunoassay reported here is important for detecting and quantifying fomesafen contamination in soil and other environmental samples with good sensitivity and high reproducibility.

Establishment of an indirect competitive immunoassay for the detection of dicamba based on a highly specific nanobody.

Dicamba, a traditional highly effective and low toxicity herbicide, has gained new life with the development of dicamba-tolerant transgenic crops in recent years. However, dicamba is highly volatile and therefore easy to cause drift damage to sensitive crops. The development of efficient and sensitive detection methods is essential for monitoring of trace dicamba in the environment. Nanobody-based immunoassay plays an important role in on-site detection of pesticides. However, now rapid and sensitive immunoassay methods based on nanobody for dicamba detection were lacking. In this study, the nanobodies specifically recognizing dicamba were successfully obtained by immunising camels and phage display library construction, and then an indirect competitive immunoassay based on Nb-242 was constructed with IC50 of 0.93 µg/mL and a linear range of 0.11-8.01 µg/mL. Nb-242 had good specificity with no cross-reactivities against the dicamba analogs other than 2,3,6-trichlorobenzoic acid and the developed immnoassay had a good correlation with the standard HPLC in the spike-recovery studies. Finally, the key amino acid Ala 123, Tyr 55, Tyr 59 and Arg 72 of Nb-242 that specifically recognizing and binding with dicamba were identified by homologous modeling and molecular docking, laying an important foundation for further structural modification of Nb-242. This study has important guiding significance for constructing immunoassay method of dicamba based on nanobody and provides a sensitive, specific, and reliable detection method that is suitable for the detection of dicamba in the environment.