Degradation dynamics, residues, processing factors, and dietary risk assessment of bisultap in citrus by LC-MS/MS.

BACKGROUND: Citrus leaf miners are a common pest harming citrus production and quality during citrus planting. During the citrus plant's growth phase, bisultap formulation was frequently used to boost yield and produce fruit of high quality. However, research on citrus's dietary risk assessment for bisultap residues, dissipation and residues is lacking. RESULTS: Liquid chromatography-tandem mass spectrometry was used to develop an accurate and sensitive analytical method for derivatizing bisultap into nereistoxin in whole fruit, pulp and peel. At various levels of addition, the mean recovery of bisultap ranged from 84.64% to 111.09% with a reasonable relative RSD (< 20%). The half-lives in Guangxi and Guizhou were 3.96 and 6.03 days, respectively. After 14-21 days of bisultap application, total residues (bisultap and its metabolite nereistoxin) in the whole fruit were from < 0.02 to 0.228 mg kg-1 in the four experiment sites. Total residue (bisultap and nereistoxin, expressed by bisultap) in whole fruit was approximately 1.05-7.23 times that of pulp. The washing process with tap water removed 85.71% to 98.78% of the bisultap residue in the whole fruit. Bisultap's risk assessment value in citrus was in the range 0.16-1.28%. CONCLUSION: In the whole citrus fruit, bisultap degrades rapidly. Bisultap residues primarily accumulate on citrus peels, and so washing and peeling citrus may effectively remove bisultap residues. For various age groups, the chronic dietary risk of bisultap was acceptable. © 2023 Society of Chemical Industry.

Comparative analysis of toxicity and metabolomic profiling of rac-glufosinate and L-glufosinate in zebrafish.

Glufosinate is a chiral pesticide, with commercial formulations such as racemic glufosinate (rac-glufosinate) and pure L-glufosinate enantiomer (L-glufosinate) on the market. There has been little research on the difference in toxicity to non-target organisms between these two main ingredients. The effects of rac-glufosinate and L-glufosinate on glutathione reductase (GR), catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) levels in zebrafish were investigated in this study. The effect of two glufosinate agents at low concentrations (0.01 and 0.1 mg/L) on these four oxidative indicators was found to be significantly lower than that of high concentrations (1 and 10 mg/L). L-glufosinate had a stronger enhancing effect on CAT, GR, and MDA content than rac-glufosinate and a stronger inhibitory effect on SOD activity than rac-glufosinate. The researchers used ultra-high-performance liquid chromatography coupled with high-resolution mass spectroscopy metabolomics to compare rac-glufosinate and L-glufosinate for metabolic disorders in adult zebrafish. Stable and obvious metabolic maps of the two agents were obtained using multivariate statistical results, such as principal component analysis and orthogonal partial minimum discriminant analysis. Compared to the control group, the rac-glufosinate and L-glufosinate treatment groups shared 151 differential metabolites, which primarily affected zebrafish energy metabolism, amino acid metabolism, and other metabolic pathways. Caffeine metabolism and biotin metabolism were among the unique pathways disrupted in rac-glufosinate-exposed zebrafish. Contrarily, L-glufosinate treatment primarily affected eight metabolic pathways, including arginine biosynthesis, melanogenesis, and glutathione metabolism. These findings may provide more detailed information on the toxicity of rac-glufosinate and L-glufosinate in zebrafish, as well as some context for assessing the environmental risk of the two glufosinate agents to aquatic organisms.

Enantioselectivity of indoxacarb enantiomers in Bombyx mori larvae: toxicity, bioaccumulation and biotransformation.

BACKGROUND: Indoxacarb is a chiral insecticide with excellent insecticidal activity against lepidopterous insects. Because of their enantioselectivity, chiral pesticides' environmental behavior at the enantiomeric level has been highlighted. The chiral stability, enantioselective bioaccumulation, biotransformation behavior of indoxacarb to a non-target insect silkworm are still unclear. RESULTS: A chiral analysis method for indoxacarb and its metabolite DCJW in silkworm was developed using liquid chromatography and high-resolution mass spectrometry (HPLC/HRMS). In silkworms, the recoveries of indoxacarb and DCJW were 86.06%-104.52% with relative standard deviation (RSD) < 9.01%. The 96-h lethal concentration (LC50 ) values of R-indoxacarb, S-indoxacarb, and enriched S-indoxacarb (2.333 S/1R) were 1.08 × 102 , 1.92, and 6.89 mg a.i. L-1 , respectively, according to the acute toxicity test results. When silkworm larvae were exposed to 1/50 of the LC50 concentration, the bioconcentration factor (BCF) of R-indoxacarb was 0.0296-0.318, and the BCF of S-indoxacarb was 0.0125-0.211. In silkworm larvae, the amount of R-DCJW produced by R-indoxacarb was 0.00610 to 2.34 times that of the parent R-indoxacarb, and the amount of S-DCJW produced by S-indoxacarb was 0.125-36.9 times that of the parent S-indoxacarb. CONCLUSION: There was no chiral transition from S-indoxacarb to R-indoxacarb or a transformation from R-indoxacarb to S-indoxacarb. Indoxacarb was preferentially bioaccumulated in silkworm larva, while S-indoxacarb bioconversion into the metabolite S-DCJW was much greater than R-indoxacarb bioconversion into R-DCJW. This study could improve understanding of the indoxacarb accumulation and transformation process in insects, as well as provide more scientific data for indoxacarb environmental and ecological risk assessment. © 2023 Society of Chemical Industry.

Identification and Quantification of Dimethachlon Degradation Products in Soils and Their Effects on Soil Enzyme Activities.

In this study, high-performance liquid chromatography-high-resolution mass spectrometry (HPLC-HRMS, Q-Exactive Orbitrap) and Compound Discoverer 3.3 were used to screen dimethachlon degradation products in soils. Four metabolites 4-(3,5-dichloroanilino)-4-oxobutanoic acid (DCBAA), 3,5-dichloroaniline (3,5-DCA), succinic acid, and muconic acid were confirmed by primary and secondary ion mass spectrometry comparisons between standards and samples. A quantitative analysis method of dimethachlon residues and four metabolites in soils was developed using HPLC-HRMS. Dimethachlon degradation in agricultural soil indoor unsterilized, sterilized, and field environments in three typical areas was measured. Dimethachlon degraded fast with a half-life of less than 1 day in three nonsterile soils. The maximum DCBAA and 3,5-DCA residues during degradation could reach 22.5-35.2% of the initial concentration of the parent dimethachlon. The metabolite DCBAA had a greater impact on soil enzyme activity than the parent dimethachlon.

Wheat yellow mosaic virus NIb targets TaVTC2 to elicit broad-spectrum pathogen resistance in wheat.

GDP-L-galactose phosphorylase (VTC2) catalyses the conversion of GDP-L-galactose to L-galactose-1-P, a vital step of ascorbic acid (AsA) biosynthesis in plants. AsA is well known for its function in the amelioration of oxidative stress caused by most pathogen infection, but its function against viral infection remains unclear. Here, we have identified a VTC2 gene in wheat named as TaVTC2 and investigated its function in association with the wheat yellow mosaic virus (WYMV) infection. Our results showed that overexpression of TaVTC2 significantly increased viral accumulation, whereas knocking down TaVTC2 inhibited the viral infection in wheat, suggesting a positive regulation on viral infection by TaVTC2. Moreover, less AsA was produced in TaVTC2 knocking down plants (TaVTC2-RNAi) which due to the reduction in TaVTC2 expression and subsequently in TaVTC2 activity, resulting in a reactive oxygen species (ROS) burst in leaves. Furthermore, the enhanced WYMV resistance in TaVTC2-RNAi plants was diminished by exogenously applied AsA. We further demonstrated that WYMV NIb directly bound to TaVTC2 and inhibited TaVTC2 enzymatic activity in vitro. The effect of TaVTC2 on ROS scavenge was suppressed by NIb in a dosage-dependent manner, indicating the ROS scavenging was highly regulated by the interaction of TaVTC2 with NIb. Furthermore, TaVTC2 RNAi plants conferred broad-spectrum disease resistance. Therefore, the data indicate that TaVTC2 recruits WYMV NIb to down-regulate its own enzymatic activity, reducing AsA accumulation to elicit a burst of ROS which confers the resistance to WYMV infection. Thus, a new mechanism of the formation of plant innate immunity was proposed.

Assessment of Heavy Metal Uptake in Potatoes Cultivated in a Typical Karst Landform, Weining County, China.

The average content of heavy metals in Weining soil of karst landforms is generally higher than that of other agricultural regions. The aim of this study was to evaluate the heavy metal content in potatoes from Weining county and to analyze the correlation between the content of heavy metals in potatoes planted in the soil of karst landform and the soil's environmental factors (soil heavy metals, soil pH, soil organic matter, altitude). Weining county (Guizhou province, China) is a typical karst landform, and has a potato production yield of 2.7 million tons. In this study, 56 soil and potato samples were collected from Weining county and the heavy metal content in the soils and potatoes was detected by inductively coupled plasma atomic mass spectrometry (ICP-MS). The content of Cr, Ni, and As in the soil was found to be higher, with almost half of the samples exceeding the maximum allowable levels. A total of 9 of the 56 samples tested had pollution load index values greater than 1.0, which indicates serious soil pollution. It was found that the ability of the potato to absorb heavy metals from the soil was very low, with the average bio-concentration factors of the metals Zn, Cu, Pb, Cr, Ni, and As being 0.087, 0.088, 0.0028, 0.0034, 0.0066, and less than 0.001, respectively. The content of the six heavy metals in the potatoes were all lower than the maximum permissible limit. The results show that a high As content in the soil could increase the content of Pb in potatoes, that a lower pH was beneficial to the bioaccumulation of Cr and Ni in potatoes, and that a high altitude is detrimental to the bioaccumulation of zinc and copper in potatoes. The HRI ranged between 1.12 × 10-2 and 5.92 × 10-2.

Four Propiconazole Stereoisomers: Stereoselective Bioactivity, Separation via Liquid Chromatography-Tandem Mass Spectrometry, and Dissipation in Banana Leaves.

In this study, we evaluated the stereoselective bioactivity of four propiconazole stereoisomers against the causal agents of the banana leaf spot disease (Curvularia lunata and Colletotrichum musae). We also evaluated the stereoselective degradation of the stereoisomers in banana leaves under field test conditions. The Superchiral S-OX column successfully separated the four propiconazole stereoisomers. X-ray single-crystal diffraction confirmed that the absolute configuration of the cis-stereoisomer-(+)-A of propiconazole was (2R,4S)-propiconazole and that of the cis-stereoisomer-(-)-A of propiconazole was (2S,4R)-propiconazole. In vitro antibacterial results revealed that (2R,4S)-(+)-propiconazole had the highest activity against the two target plant fungi. In this study, a new and efficient high-performance liquid chromatography tandem mass spectrometry method was developed for the determination of the four stereoisomeric residues of propiconazole in banana leaves. The mean recoveries of the method for the stereoisomers were 76.3-103% with relative standard deviations of 1.25-11.4%. The four propiconazole stereoisomers had a detection limit of 0.002-0.006 mg/kg and a limit of quantification of 0.02-0.03 mg/kg in banana leaves. Propiconazole-(-)-B and propiconazole-(-)-A degraded slightly faster than their corresponding enantiomers propiconazole-(+)-B and propiconazole-(+)-A in banana leaves collected from three typical banana production areas.

Dissipation Dynamics, Terminal Residues and Dietary Risk Assessment of Two Isomers of Dimethacarb in Rice by HPLC-MS/MS.

Dimethacarb is a carbamate insecticide developed in China that contains 3,5-dimethylphenyl methylcarbamate (XMC) and 3,4-dimethylphenyl methylcarbamate (MPMC) isomers. Dimethacarb has been registered for use in rice in China, but no residue or degradation of dimethacarb in rice has been reported and the maximum residue limits (MRLs) for rice have not been established. A versatile high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed with modified QuEChERS sample preparation to determine two isomers of dimethacarb in rice. The average recovery of XMC and MPMC in brown rice, rice husk, and rice straw ranged from 71.69 to 100.60%, with spike levels of 0.01 to 1 mg/kg and relative standard deviations (RSDs) of 0.21 to 8.41%. Field experiments showed that the half-lives of XMC and MPMC in rice straw were 4.08 to 4.23 days and 3.48 to 3.69 days, respectively. Final residues of XMC and MPMC in rice husk after 21 days of spraying at six sites ranged from 0.23-2.65 mg/kg and 0.06-1.10 mg/kg, and <0.01-0.16 mg/kg and <0.01-0.04 mg/kg in brown rice. The ratio of XMC to MPMC content in the rice husk differed from the original 50% dimethacarb EC, indicating the difference in the degradation rate of XMC and MPMC. The estimated risk quotient (RQ) for both XMC and MPMC was less than 30%. These data for residues from six representative locations could provide a reference for establishing the MRL of dimethacarb in rice.

[Spinal fixed-point rotating reduction in treating lumbar disc herniation by three-dimensional MRI].

OBJECTIVE: To observe three-dimensional space position change of nucleus pulposus and nerve root before and after treatment of lumbar disc herniation by spinal fixed-point rotating reduction, and explore the mechanisms. METHODS: Totally 52 patients with L5S1 lumbar disc hernation treated by spinal fixed-point rotating reduction were collected from April 2009 to June 2011. There were 33 males and 19 females with an average age of 34.6 years old (ranged, 19 to 55). Three-dimensional MRI were performed to observe relationship between nucleus pulposus and related nerve root,configuration change of spine and pelvic on coronary MRI. RESULTS: MRI showed relationship between nucleus pulposus and related nerve root mainly located on axillary, shoulder, front and surround. Vertebral displacement disappeared, lumbocrural pain alleviated after manipulative therapy. All patients were followed up from 2 to 28 months with an average of 12 months, and no recurred. All patients recovered work. Nucleus pulposus had no change,while lumbral spinal and pelvic curve changed before and after admission. CONCLUSION: Lumbar disc herniation combined with single (multiple) vertebral displacement,can cause biomechanical properties of nucleus puplosus and related nerve root, while spinal fixed-point rotating reduction can correct vertebral displacement, recover balance between inside and outside of spinal.

Reduction in nerve root compression by the nucleus pulposus after Feng's Spinal Manipulation.

Ninety-four patients with lumbar intervertebral disc herniation were enrolled in this study. Of these, 48 were treated with Feng's Spinal Manipulation, hot fomentation, and bed rest (treatment group). The remaining 46 patients were treated with hot fomentation and bed rest only (control group). After 3 weeks of treatment, clinical parameters including the angle of straight-leg raising, visual analogue scale pain score, and Japanese Orthopaedic Association score for low back pain were improved. The treatment group had significantly better improvement in scores than the control group. Magnetic resonance myelography three-dimensional reconstruction imaging of the vertebral canal demonstrated that filling of the compressed nerve root sleeve with cerebrospinal fluid increased significantly in the treatment group. The diameter of the nerve root sleeve was significantly larger in the treatment group than in the control group. However, the sagittal diameter index of the herniated nucleus pulposus and the angle between the nerve root sleeve and the thecal sac did not change significantly in either the treatment or control groups. The effectiveness of Feng's Spinal Manipulation for the treatment of symptoms associated with lumbar intervertebral disc herniation may be attributable to the relief of nerve root compression, without affecting the herniated nucleus pulposus or changing the morphology or position of the nerve root.

[Study on the mechanism of Feng's spinal manipulation for treatment of lumbar disk hernation with a calcified herniated mass using 3D CT].

OBJECTIVE: To measure position changes of lumber disk herniation before and after treatment of Feng's spinal manipulation to study the mechanism of the manipulation for lumber disk herniation. METHODS: In 2010, 8 patients with lumber disk herniation were treated by Feng's spinal manipulation, including 3 males and 5 females who ranged in age from 14 to 53 years with a mean of 35.4 years. The patients received CT scan before and after treatment. All images were reconstructed to measure the distance between the apex of the calcified lumber disk herniation and the top of the next adjacent spinal process. RESULTS: The position of calcified lumber disk herniation underwent change after Feng's spinal manipulation, with a slight subluxation between the two adjacent vertebrae. CONCLUSION: If subluxation is restored,the relation between the nerve root and the hernation will undergo change, followed by subsequent change of the hernation mass, thus restoring the inner-outer balance of the spinal column system.

[Study on the efficacy of orthopedic footwear in treating lumbar intervertebral disc herniation with spinal manipulation].

OBJECTIVE: To observe the efficacy and mechanism of orthopedic footwear in treating lumbar intervertebral disc herniation with spinal manipulation. METHODS: From September 2009 to September 2010, 44 patients with the lumbar intervertebral disc herniation with posture change were selected in the study. There were 28 males (aged from 24 to 58 years) and 16 females (aged from 21 to 60 years). Firstly, the average EMG (AEMG) and spectrum area (SPA) of bilateral lumbar erector spinae of the patients were tested by surface electromyogram (sEMG), and then absolute value of the difference between AEMG and SPA (larAEMG and larSPA) were compared. After that, they were randomly divided into two groups (experiment group and control group), each group had 22 cases. The patients of experiment group received the spinal manipulation treatment assisted with orthopedic footwear and the other group received the spinal manipulation treatment only. Orthopedic footwear was put on by leg with lower iliac crest line, sole thickness of which depended on the degree of pelvic tilt. According to mitigation degree of symptom and sign, sole thickness was modified till removal of orthopedic footwear. Manipulative therapeutic method which was manipulative by doctors set spinal process to normal anatomical position. Manipulative treatment was 2 - 3 times every week. The clinical healing time were observed in the two groups. RESULTS: The larSPA was 0.12 +/- 0.73, 0.65 +/- 0.61 and the larAEMG was 3.43 +/- 25.56, 21.74 +/- 20.34 in standing 1 minute of two positions of patients with orthopedic footwear and without orthopedic footwear, respectively; the larSPA was 0.15 +/- 0.36, 0.57 +/- 0.24 and the larAEMG was 4.65 +/- 12.87, 25.18 +/- 16.58 in walking 1 minute of two positions of patients with orthopedic footwear and without orthopedic footwear. There were significant difference between the two groups (P < 0.01). The time of healing well in experiment group and control group were respectively (20.36 +/- 4.92) d and (28.14 +/- 7.13) d, experiment group was shorter than that of control group (P < 0.01). CONCLUSION: Orthopedic footwear can obviously improve the unsymmetrical shrink of bilateral lumbar erector spinae and balance lumbar muscle. Therefore,orthopedic footwear can create favourable conditions for the spinal manipulation in treatment of lumbar intervertebral disc herniation, which can shorten the healing well.

[Treatment of the lumbar disc herniation of sequestered type with Feng's spinal manipulation].

OBJECTIVE: To evaluate the clinical effect of the treatment for sequestered type lumbar disk herniation (SLDH) with FENG's spinal manipulation. METHODS: Forty-one patients (27 male, 14 female) were treated by FENG's spinal manipulation. The clinical results were measured by the Japanese and FENG's lumbar treatment standard and evaluated by scoring system for assessment of treatment for low back pain between pre- and post-treatment. To measure MRI sagittal index (SI) of lumbar disc herniation between pre- and post-treatment. RESULTS: The score of subjective symptoms and clinical signs increased obviously after treatment. There was no statistical difference of SI between pre- and post-treatment (P<0.05). The outcome of treatment was satisfying. CONCLUSION: The major pathologic change of SLDH is the single/multiple vertebral subluxation. FENG's spinal manipulation can correct the vertebral subluxation which leading to the series of clinical manifestations. The good clinical outcome may due to the alleviation of distortion and tension of dura and nerve root with the recovery of the spinal column's stability.

[Clinical meaning of the surrounding compression on the nerve root by the protruded nucleus pulposus and facet or lamina (ligamentum flavum): analysis of CT (MRI) axial slice images of 71 patients with lumbar disc herniation].

OBJECTIVE: To observe the pinching action to the nerve root by the lumbar disc herniation and facet or lamina (ligamentum flavum) and evaluate its clinical meaning. METHODS: Seventy-one patients were divided into 3 groups according to the size of distance between protrusion of nuclear and facet or lamina (ligamentum flavum). The degree of the straight leg raising of the affected side (SLR) and the sagittal index (SI) of lumbar disk herniation were measured and analyzed among them. RESULTS: There was no corelation between the affected degree of SLR and sex, age and SI of patient (P > 0.05). The coefficient between distance group and the affected degree of SLR is-0.878 7 (P < 0.01). CONCLUSION: The degree of the surrounding compression by the protrusion of nuclear and facet or lamina (ligamentum flavum) reflects the injuried severity of the nerve root.