Insecticidal activity of the spider neurotoxin PPTX-04 through modulating insect voltage-gated sodium channel.

Ion channels on cell membrane are molecular targets of more than half peptide neurotoxins from spiders. From Pardosa pseudoannulata, a predatory spider on a range of insect pests, we characterized a peptide neurotoxin PPTX-04 with an insecticidal activity. PPTX-04 showed high toxicity to Nilaparvata lugens, a main prey of P. pseudoannulata, and the toxicity was not affected by the resistance to etofenprox (IUPAC chemical name:1-ethoxy-4-[2-methyl-1-[(3-phenoxyphenyl)methoxy]propan-2-yl]benzene, purity: 99%). On N. lugens voltage-gated sodium channel NlNav1 expressed in Xenopus oocytes, PPTX-04 prolonged the channel opening and induced tail currents, which is similar to pyrethroid insecticides. However, PPTX-04 potency on NlNav1 was not affected by mutations conferring pyrethroid resistance in insects, which revealed that PPTX-04 and pyrethroids should act on different receptors in NlNav1. In contrast, two mutations at the extracellular site 4 significantly reduced PPTX-04 potency, which indicated that PPTX-04 would act on a potential receptor containing the site 4 in NlNav1. The result from the molecular docking supported the conclusion that the binding pocket of PPTX-04 in NlNav1 should contain the site 4. In summary, PPTX-04 had high insecticidal activity through acting on a distinct receptor site in insect Nav, and was a potential resource to control insect pests and manage resistance to pyrethroids.

Research progress of flexible pressure sensor based on MXene materials.

Flexible pressure sensors overcome the limitations of traditional rigid sensors on the surface of the measured object, demonstrating broad application prospects in fields such as sports health and vital sign monitoring due to their excellent flexibility and comfort in contact with the body. MXene, as a two-dimensional material, possesses excellent conductivity and abundant surface functional groups. Simultaneously, MXene's unique layered structure and large specific surface area offer a wealth of possibilities for preparing sensing elements in combination with other materials. This article reviews the preparation methods of MXene materials and their performance indicators as sensing elements, discusses the controllable preparation methods of MXene materials and the impact of their physical and chemical properties on their functions, elaborates on the pressure sensing mechanism and evaluation mechanism of MXene materials. Starting from the four specific application directions: aerogel/hydrogel, ink printing, thin film/electronic skin, and fiber fabric, we introduce the research progress of MXene flexible pressure sensors from an overall perspective. Finally, a summary and outlook for developing MXene flexible pressure sensors are provided.

Cys-loop ligand-gated ion channel superfamily of Pardosa pseudoannulata: Implication for natural enemy safety.

Cys-loop ligand-gated channels mediate neurotransmission in insects and are receptors for many insecticides. Some insecticides acting on cysLGIC also have lethal effects on non-targeting organisms, but the mechanism of this negative effect is unclear due to information absence. The identification and analysis of cysLGIC family in Pardosa pseudoannulata, a pond wolf spider, can deepen the understanding of insecticides for natural enemy safety. Thirty-four cysLGIC genes were identified in P. pseudoannulata genome, including nicotinic acetylcholine receptors, γ-aminobutyric acid gated chloride channels, glutamate-gated chloride channels, histamine-gated chloride channels, and pH-sensitive chloride channels. The expansion of GABACls and HisCls accounts for the large number of cysLGICs in P. pseudoannulata, and the alternative splicing events in nAChR and RDL subunits enriched the diversity of the superfamily. Most cysLGIC genes show the highest expression in brain and lowest expression in the early-egg sac stage. Variable residues (R81, V83, R135, N137, F190, and W197) in P. pseudoannulata nAChR ß subunits and critical differences in α6 subunit TM4 region compared with insects would apply for the insensitivity to neonicotinoids and spinosyn. In contrast, avermectin and dieldrin may be lethal to P. pseudoannulata due to the similar drugs binding sites in GluCls compared with insects. These findings will provide a valuable clue for natural enemy protection and environmentally friendly insecticide development.

An OBP gene highly expressed in non-chemosensory tissues affects the phototaxis and reproduction of Spodoptera frugiperda.

Insect odorant binding proteins (OBPs) were initially regarded as carriers of the odorants involved in chemosensation. However, it had been observed that a growing number of OBP genes exhibited broad expression patterns beyond chemosensory tissues. Here, an OBP gene (OBP31) was found to be highly expressed in the larval ventral nerve cord, adult brain and male reproductive organ of Spodoptera frugiperda. An OBP31 knockout strain (OBP31-/- ) was generated by CRISPR/Cas9 mutagenesis. For OBP31-/- , the larvae needed longer time to pupate, but there was no difference in the pupal weight between OBP31-/- and wild type (WT). OBP31-/- larvae showed stronger phototaxis than the WT larvae, indicating the importance of OBP31 in light perception. For mating rhythm of adults, OBP31-/- moths displayed an earlier second mating peak. In the cross-pairing of OBP31-/- and WT moths, the mating duration was longer, and hatchability was lower in OBP31-/- group and OBP31+/- ♂ group than that in the WT group. These results suggested that OBP31 played a vital role in larval light perception and male reproductive process and could provide valuable insights into understanding the biological functions of OBPs that were not specific in chemosensory tissues.

Cryo-EM structures of Kv1.2 potassium channels, conducting and non-conducting.

We present near-atomic-resolution cryo-EM structures of the mammalian voltage-gated potassium channel Kv1.2 in open, C-type inactivated, toxin-blocked and sodium-bound states at 3.2 Å, 2.5 Å, 3.2 Å, and 2.9Å. These structures, all obtained at nominally zero membrane potential in detergent micelles, reveal distinct ion-occupancy patterns in the selectivity filter. The first two structures are very similar to those reported in the related Shaker channel and the much-studied Kv1.2-2.1 chimeric channel. On the other hand, two new structures show unexpected patterns of ion occupancy. First, the toxin α-Dendrotoxin, like Charybdotoxin, is seen to attach to the negatively-charged channel outer mouth, and a lysine residue penetrates into the selectivity filter, with the terminal amine coordinated by carbonyls, partially disrupting the outermost ion-binding site. In the remainder of the filter two densities of bound ions are observed, rather than three as observed with other toxin-blocked Kv channels. Second, a structure of Kv1.2 in Na+ solution does not show collapse or destabilization of the selectivity filter, but instead shows an intact selectivity filter with ion density in each binding site. We also attempted to image the C-type inactivated Kv1.2 W366F channel in Na+ solution, but the protein conformation was seen to be highly variable and only a low-resolution structure could be obtained. These findings present new insights into the stability of the selectivity filter and the mechanism of toxin block of this intensively studied, voltage-gated potassium channel.

Heterogeneous Cu2O-SnO2 doped polydopamine fenton-like nanoenzymes for synergetic photothermal-chemodynamic antibacterial application.

Wound infections caused by drug-resistant bacteria pose a great threat to human health, and the development of non-drug-resistant antibacterial approaches has become a research priority. In this study, we developed Cu2O-SnO2 doped polydopamine (CSPDA) triple cubic antibacterial nanoenzymes with high photothermal conversion efficiency and good Fenton-like catalase performance. CSPDA antibacterial nanoplatform can catalyze the generation of hydroxyl radical (·OH) from H2O2 at low concentration (50 µg∙mL-1) under 808 nm near-infrared (NIR) irradiation to achieve a combined photothermal therapy (PTT) and chemodynamic therapy (CDT). And the CSPDA antibacterial nanoplatform displays broad-spectrum and long-lasting antibacterial effects against both Gram-negative Escherichia coli (100 %) and Gram-positive Staphylococcus aureus (100 %) in vitro. Moreover, in a mouse wound model with mixed bacterial infection, the nanoplatform demonstrates a significant in vivo bactericidal effect while remaining good cytocompatible. To conclude, this study successfully develops an efficient and long-lasting bacterial infection treatment system. This system provided different options for future studies on the design of synergistic antimicrobial therapy. Hence, the as-synthesized synergetic photothermal therapy and chemodynamic therapy nanoenzymes have rapid and long-term bactericidal ability, well-conglutinant performance and effectively preventing wound infection for clinical application. STATEMENT OF SIGNIFICANCE: Wound infections caused by drug-resistant bacteria pose a great threat to human health, and the development of non-drug-resistant antibacterial approaches has become a research priority. In this study, we developed Cu2O-SnO2 doped polydopamine (CSPDA) triple cubic yolk-like antibacterial nanoenzymes with high photothermal conversion efficiency and Fenton-like catalase effect for photothermal and Chemodynamic antibacterial therapy, Meanwhile, the nanocomposites exhibit good antibioadhesion in a natural water environment for a long-time immersion. In conclusion, this study successfully develops an efficient and long-lasting bacterial infection treatment system. These findings present a pioneering strategy for future research on the design of synergistic antibacterial and antibioadhesive systems.

Plasticity of the Gene Transcriptional Level and Microbiota in the Gut Contributes to the Adaptability of the Fall Armyworm to Rice Plants.

Insects coordinate a variety of mechanisms to overcome the feeding challenges, including gene transcriptional plasticity and stable symbioses in the gut. Here, Spodoptera frugiperda larvae were reared on corn and rice plants for successive generations to obtain two specific strains. The rice strain displayed a longer developmental period, lower female fecundity, and intrinsic growth rate at G1 and G5 but not at G10. KEGG analysis of the G1, G5, and G11 gut transcriptome indicated that detoxification enzymes might play vital roles in host adaptation. RNAi-mediated knockdown of CYP12A2 and UGT41B8, which were highly expressed in the gut of the rice strain, significantly reduced the larval adaptability to rice. Besides, the dsCYP12A2-treated larvae displayed an increased sensitivity to luteolin, a flavonoid phytochemical. The KEGG function prediction of gut microbiota indicated that the high enrichment level of metabolism in the rice strain would play essential roles in rice adaptation.

A robust lateral shift free (LSF) electrothermal micromirror with flexible multimorph beams.

Electrothermal bimorph-based scanning micromirrors typically employ standard silicon dioxide (SiO2) as the electrothermal isolation material. However, due to the brittle nature of SiO2, such micromirrors may be incapable to survive even slight collisions, which greatly limits their application range. To improve the robustness of electrothermal micromirrors, a polymer material is incorporated and partially replaces SiO2 as the electrothermal isolation and anchor material. In particular, photosensitive polyimide (PSPI) is used, which also simplifies the fabrication process. Here, PSPI-based electrothermal micromirrors have been designed, fabricated, and tested. The PSPI-type micromirrors achieved an optical scan angle of ±19.6° and a vertical displacement of 370 µm at only 4 Vdc. With a mirror aperture size of 1 mm × 1 mm, the PSPI-type micromirrors survived over 200 g accelerations from either vertical or lateral directions in impact experiments. In the drop test, the PSPI-type micromirrors survived falls to a hard floor from heights up to 21 cm. In the standard frequency sweeping vibration test, the PSPI-type micromirrors survived 21 g and 29 g acceleration in the vertical and lateral vibrations, respectively. In all these tests, the PSPI-type micromirrors demonstrated at least 4 times better robustness than SiO2-type micromirrors fabricated in the same batch.

Insecticidal toxicity of ω-Atypitoxin-Cs1a and its inhibitory effects on insect voltage-gated calcium channels.

BACKGROUND: Excessive use of chemical insecticides raises concerns about insecticide resistance, urging the development of novel insecticides. Peptide neurotoxins from spider venom are an incredibly rich source of ion channel modulators with potent insecticidal activity. A neurotoxin U1-Atypitoxin-Cs1a from the spider Calommata signata was annotated previously. It was of interest to investigate its insecticidal activity and potential molecular targets. RESULTS: Cs1a was heterologously expressed, purified and pharmacologically characterized here. The recombinant neurotoxin inhibited high-voltage-activated calcium channel currents with an median inhibitory concentration (IC50 ) value of 0.182 ± 0.026 µm on cockroach DUM neurons and thus was designated as ω-Atypitoxin-Cs1a. The recombinant Cs1a was toxic to three insect pests of agricultural importance, Nilaparvata lugens, Spodoptera frugiperda and Plutella xylostella with median lethal concentration (LD50 ) values of 0.121, 0.172 and 0.356 nmol g-1 , respectively, at 24 h postinjection. Cs1a was equivalently toxic to both insecticide-susceptible and -resistant insects. Cs1a exhibited low toxicity to Danio rerio with an LD50 of 2.316 nmol g-1 . CONCLUSION: Our results suggest that ω-Atypitoxin-Cs1a is a potent CaV channel inhibitor and an attractive candidate reagent for pest control and resistance management. © 2023 Society of Chemical Industry.

Pattern Recognition Analysis of Metabolites in Escherichia coli Based on ESI-Orbitrap Mass Spectrometry.

To achieve rapid detection of carbapenem-resistant Escherichia coli strains, a pattern recognition method based on electrospray ionization Orbitrap mass spectrometry (ESI-Orbitrap MS) was used for the analysis of drug-resistant, and sensitive strains of metabolites were analyzed. Results of five clustering methods applied to analytical data of metabolites were evaluated using iso-phenotypic coefficients. The effectiveness of three methods, principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and orthogonal partial least squares discriminant analysis (OPLS-DA), was compared. Univariate statistics such as t-test and fold change were also used to examine the screened differential information. Both PLS-DA and OPLS-DA could achieve rapid identification of strain classes, and OPLS-DA was more powerful in screening 96 significantly different ions. This work is expected to be useful for rapid and accurate identification of strains.

Optimization Design of the Bending-Vibration Resistance of Magnetorheological Elastomer Carbon Fibre Reinforced Polymer Sandwich Sheets.

An optimization design of the bending-vibration resistance of magnetorheological elastomer carbon fibre reinforced polymer sandwich sheets (MECFRPSSs) was studied in this paper. Initially, by adopting the classical laminate theory, the Reddy's high-order shear deformation theory, the Rayleigh-Ritz method, etc., an analytical model of the MECFRPSSs was established to predict both bending and vibration parameters, with the three-point bending forces and a pulse load being considered separately. After the validation of the model was completed, the optimization design work of the MECFRPSSs was conducted based on an optimization model developed, in which the thickness, modulus, and density ratios of magnetorheological elastomer core to carbon fibre reinforced polymer were taken as design variables, and static bending stiffness, the averaged damping, and dynamic stiffness parameters were chosen as objective functions. Subsequently, an artificial bee colony algorithm was adopted to execute single-objective, dual-objective, and multi-objective optimizations to obtain the optimal design parameters of such structures, with the convergence effectiveness being examined in a validation example. It was found that it was hard to improve the bending, damping, and dynamic stiffness behaviours of the structure simultaneously as the values of design variables increased. Some compromised results of design parameters need to be determined, which are based on Pareto-optimal solutions. In further engineering application of the MECFRPSSs, it is suggested to use the corresponding design parameters related to a turning point to better exert their bending-vibration resistance.

EcR/USP-1-mediated ecdysteroid signaling regulates wolf spider (Pardosa pseudoannulata) development and reproduction.

Lycosidae females demonstrate meticulous maternal care of offspring by carrying egg sacs and juvenile spiderlings during the reproductive stage. Nuclear receptors (NRs), especially the ecdysone receptor (EcR) and ultraspiracle (USP), have attracted considerable attention in the regulation of arthropod development and reproduction due to their pivotal roles in ecdysteroid signaling cascades. In the present study, 23 NRs, including one EcR and two USPs, were identified in the genome of the predatory wolf spider Pardosa pseudoannulata. RNA interference (RNAi) targeting EcR and USP-1 inhibited spiderling development and resulted in non-viable eggs in the egg sacs. EcR and USP-1 responded to changes in ecdysteroid levels, and interference in ecdysteroid biosynthesis led to similar phenotypes as dsEcR and dsUSP-1 treatments. These findings suggest that EcR/USP-1-mediated ecdysteroid signaling regulates P. pseudoannulata development and reproduction. The P. pseudoannulata females with suppressed ecdysteroid signaling proactively consumed their non-viable egg sacs, resulting in a 7.19 d shorter first reproductive cycle than the controls. Termination of the failed reproductive cycle enabled the spiders to produce a new egg sac more rapidly. This reproductive strategy may partially rescue the reduction in population growth due to non-viable eggs and compensate for the physiological expenditure of wasted maternal care, which would be beneficial for the conservation of P. pseudoannulata populations and their natural control of insect pests.

Concave octopus-like PtCu nanoframe mediated photo-electro Fenton catalysis for fast organic dyestuff elimination.

In this work, a photo-electro Fenton catalytic nanoplatform based on concave octopus-like PtCu nanoframes was fabricated for organic dyestuff degradation. The electrochemical oxidation reaction was performed to generate hydrogen peroxide (H2O2) on the interface of PtCu nanoframes via a promising electro-Fenton process for on-demand aqueous remediation.

Rapid Identification of Polypeptide from Carbapenem-Resistant and Susceptible Escherichia coli via Orbitrap-MS and Pattern Recognition Analyses.

A rapid and accurate analytical method was established to identify CREC and CSEC. Orbitrap-MS was used to detect the polypeptide of CREC and CSEC strains, and MS data were analyzed by pattern recognition analyses such as hierarchical cluster analysis (HCA), principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and orthogonal partial least squares discriminant analysis (OPLS-DA). HCA based on the farthest distance method could well distinguish the two types of E. coli, and the cophenetic correlation coefficient of the farthest distance method was 0.901. Comparing the results of PCA, PLS-DA, and OPLS-DA, OPLS-DA exhibited the highest accuracy in predicting the CREC and CSEC strains. A total of 26 compounds were identified, and six of the compounds were the highly significant difference between the two types of strains. MS combined with pattern recognition can achieve a more comprehensive and efficient statistical analysis of complex biological samples.

Regulation of juvenile hormone and ecdysteroid analogues on the development of the predatory spider, Pardosa pseudoannulata, and its regulatory mechanisms.

Insecticides harm the beneficial organisms, such as predatory spiders, through direct killing or regulation of the development and reproduction. In this study, the bioassay showed that the treatment of juvenile hormone (JH) analogue fenoxycarb delayed the moulting of Pardosa pseudoannulata, a dominant predatory spider in paddy fields. In order to figure out the regulatory mechanism of fenoxycarb on the spider development, we systematically analyzed JH biosynthesis in P. pseudoannulata. All genes involved in JH biosynthesis pathway were retrieved from the genome of P. pseudoannulata, except for CYP15A1. The absence of CYP15A1 was in agreement with the identification of methyl farnesoate (MF) rather than JH III in the spider. The delayed moulting and decreased expression of JH biosynthesis-related genes in the MF-applied spiderlings supported that MF was an active JH. Fenoxycarb treatment significantly upregulated the transcriptional level of JH biosynthesis-related genes and consequently delayed the spiderling moulting. In the spider development, ecdysteroid played the opposite role, in contrast to MF, to accelerate the development, as our previous study. Here we found that the treatment of ecdysteroid analogue tebufenozide accelerated P. pseudoannulata spiderling moulting, which resulted from the expressional suppression of ecdysteroid biosynthesis-related genes. In total, the JH and ecdysteroid analogues affected the development of P. pseudoannulata by the expressional regulation of biosynthesis-related genes, which would be helpful for the evaluation of hormone analogue insecticides in environmental safety, and useful for the protection and application of P. pseudoannulate and related spider species.

Sulfur-doped graphitic carbon nitride nanosheets as a sensitive fluorescent probe for detecting environmental and intracellular Ag.

Silver is widely used in medical materials, photography, electronics and other industries as a precious metal. The large-scale industrial production of silver-containing products and liquid waste emissions aggravate the environmental pollution. Silver ion is one of the most toxic metal ions, causing pollution to the environment and damage to public health. Therefore, the efficient and sensitive detection of Ag+in the water environment is extremely important. Sulfur-doped carbon nitride nanosheets (SCN Ns) were prepared by melamine and thiourea via high-temperature calcination. The morphology, chemical composition and surface functional groups of the SCN Ns were characterized by SEM, TEM, XRD, XPS, and FT-IR. The fluorescence of SCN Ns was gradually quenched as the Ag+concentration increased. The detection limit for Ag+was as low as 0.28 nM. The quenching mechanism mainly is attributed to static quenching. In this paper, SCN Ns were used as the fluorescent probe for detecting Ag+. SCN Ns have successfully detected Ag+in different environmental aqueous samples and cells. Finally, SCN Ns were further applied to the visual quantitative detection of intracellular Ag+.

[Trend Changes in Ozone Pollution and Sensitivity Analysis of Ozone in Henan Province].

Based on air quality station data and satellite remote sensing data, the interannual variation characteristics and seasonal variation trends of near-surface ozone (O3) in Henan province were studied, and the variation in O3 sensitivity was analyzed. The results showed that the O3 concentration near the surface of Henan province increased first and then decreased from 2015 to 2020. The highest O3 concentration was found in 2018, and the annual mean of the maximum daily 8 h moving mean (MDA8) of O3 was 110.70 µg·m-3. The difference in MDA8 values among different stations gradually decreased. From 2015 to 2020, the average monthly MDA8 in Henan province showed an upward trend, with a growth rate of 2.46 µg·(m3·a)-1. According to the MK trend test, except for in Luohe, Nanyang, and Pingdingshan, the rising trend in other cities was significant (P<0.05). The concentration of MDA8 in the four seasons also showed an increasing trend during the 6 years as follows:autumn (19.31%)>winter (17.09%)>spring (16.82%)>summer (7.24%). From 2015 to 2019, the high value of tropospheric NO2 was concentrated in the northwest of Henan province, and the concentration showed a decreasing trend with a decreasing rate of 0.34×1015 molecules·(cm2·a)-1, whereas the tropospheric HCHO showed a slow rising trend with an annual growth rate of 0.19×1015 molecules·(cm2·a)-1, with a higher concentration in the northern urban area. The O3 sensitivity control area from 2015 to 2019 showed that most of the eastern part of Henan province belonged to the VOCs limited category.

Simulation and Optimization of Connection-Strength Performance of Axial Extrusion Joint.

Axial extrusion-connection technology is one of the important connection technologies for hydraulic piping systems, with high sealing performance and mechanical strength. In this paper, the finite-element-modeling method is used to simulate the experimental process of the connection strength of the axial extrusion joint. The generation mechanism and calculation method of the connection strength are analyzed. To optimize the joint strength, orthogonal testing and grey correlation analysis are used to analyze the influencing factors of joint strength. The key factors affecting joint strength are obtained as the friction coefficient µ1, µ2 between joint components and the groove angle θ1 of the fittings body. The back-propagation (BP) neural-network algorithm is used to establish the connection-strength model of the joint and the genetic algorithm is used to optimize it. The optimal connection strength is 8.237 kN and the optimal combination of influencing factors is 0.2, 0.4 and 76.8°. Compared with the prediction results of the neural-network genetic algorithm, the relative error of the finite-element results is 3.9%, indicating that the method has high accuracy. The results show that the extrusion-based joining process offers significant advantages in the manufacture of high-strength titanium tubular joints.

DeepIDA: Predicting Isoform-Disease Associations by Data Fusion and Deep Neural Networks.

Alternative splicing produces different isoforms from the same gene locus, it is an important mechanism for regulating gene expression and proteome diversity. Although the prediction of gene(ncRNA)-disease associations has been extensively studied, few (or no) computational solutions have been proposed for the prediction of isoform-disease association (IDA) at a large scale, mainly due to the lack of disease annotations of isoforms. However, increasing evidences confirm the associations between diseases and isoforms, which can more precisely uncover the pathology of complex diseases. Therefore, it is highly desirable to predict IDAs. To bridge this gap, we propose a deep neural network based solution (DeepIDA) to fuse multi-type genomics and transcriptomics data to predict IDAs. Particularly, DeepIDA uses gene-isoform relations to dispatch gene-disease associations to isoforms. In addition, it utilizes two DNN sub-networks with different structures to capture nucleotide and expression features of isoforms, Gene Ontology data and miRNA target data, respectively. After that, these two sub-networks are merged in a dense layer to predict IDAs. The experimental results on public datasets show that DeepIDA can effectively predict IDAs with AUPRC (area under the precision-recall curve) of 0.9141, macro F-measure of 0.9155, G-mean of 0.9278 and balanced accuracy of 0.9303 across 732 diseases, which are much higher than those of competitive methods. Further study on sixteen isoform-disease association cases again corroborates the superiority of DeepIDA. The code of DeepIDA is available at http://mlda.swu.edu.cn/codes.php?name=DeepIDA.

[Dynamic Process of Nitrogen and Phosphorus Export and Loss Load in an Intensive Orchard with Ridge and Furrow Plantation in the Three Gorges Reservoir Area].

To comprehend the runoff load of nitrogen (N) and phosphorus (P) and the impact on the receiving river in an agricultural area with an intensive orchard plantation and a longitudinal ridge and furrow morphology in the Three Gorges Reservoir Area, the runoff and N and P concentrations were dynamically monitored in a typical citrus orchard catchment in Wanzhou Country, Chongqing, China. The results showed that the nutrient concentration in runoff water from the intensive citrus planting catchment was very high. The average annual event mean concentrations (EMC) were 9.31 mg·L-1 for total nitrogen (TN), 8.11 mg·L-1 for dissolved nitrogen (DN), 5.66 mg·L-1 for nitrate nitrogen (NN), 0.51 mg·L-1 for ammonium nitrogen (AN), 0.87 mg·L-1 for total phosphorus, 0.56 mg·L-1 for solved phosphorus (DP), and 0.32 mg·L-1 for particulate phosphorus (DP). In addition, the annual loss loads were 13.43, 12.20, 8.77, 0.75, 1.26, 0.84, and 0.42 kg·(hm2·a)-1 for TN, DN, NN, AN, TP, DP, and PP, respectively. The annual average concentrations of TN and TP were 8.49 mg·L-1 and 0.87 mg·L-1, respectively, which exceeded the category V values of the surface water quality standards (GB3838-2002) by 4.25 times and 2.2 times, respectively, and also exceeded the internationally recognized thresholds for the eutrophication of waterbodies. The TN and TP loss load from storm runoff was one of the main reasons for the degradation of the river water quality, thus suggesting the need to treat surface runoff and control runoff nutrient losses, especially during the first storm events after fertilization. During two typical long-duration springtime rainfall events after fertilization, the loads of nitrate nitrogen (NN) and dissolved phosphorus (DP) were 4.94 kg·hm-2 and 0.28 kg·hm-2, respectively, which accounted for 92.90% and 64.69% of the total annual TN and TP loss loads, respectively. The loads of NN and DP in a short-duration high-intensity rainfall event were 0.52 and 0.05 kg·hm-2 respectively, which accounted for 65.92% and 74.88% of the total annual TN and TP loss loads, respectively. The DN and DP were the main forms of nitrogen and phosphorus losses from the intensive citrus orchard with a longitudinal ridge and furrow morphology. Meanwhile, the catchment showed a significant first-flush phenomenon during a typical rainfall event, with a total of 58.0%, 57.0%, 58.5%, 79.0%, 62.0%, 63.5%, and 60.0% of the mass of TN, DN, NN, AN, TP, DP, and PP in the initial 20% of the runoff, respectively. Hence, controlling the surface runoff at the early runoff stage plays an important role in reducing nutrient losses.