Glycaemia risk index uncovers distinct glycaemic variability patterns associated with remission status in type 1 diabetes.

AIMS/HYPOTHESIS: The aim of this work was to define a unique remission status using glycaemia risk index (GRI) and other continuous glucose monitoring (CGM) metrics in individuals with type 1 diabetes for improved phenotyping. METHODS: A group of 140 individuals with type 1 diabetes were recruited for a cross-sectional study. The participants were categorised into four groups based on their remission status, which was defined as insulin-dose-adjusted A1c (IDAA1c) <9 or C-peptide ≥300 pmol/l: new-onset (n=24); mid-remission (n=44); post-remission (n=44); and non-remission (individuals who did not experience remission, n=28). Participants in the remission phase were referred to as 'remitters', while those who were not in the remission phase were referred to as 'non-remitters', the latter group including new-onset, post-remission and non-remission participants. Clinical variables such as HbA1c, C-peptide and insulin daily dose, as well as IDAA1C and CGM data, were collected. The patterns of CGM metrics were analysed for each group using generalised estimating equations to investigate the glycaemic variability patterns associated with remission status. Then, unsupervised hierarchical clustering was used to place the participants into subgroups based on GRI and other CGM core metrics. RESULTS: The glycaemic variability patterns associated with remission status were found to be distinct based on the circadian CGM metrics. Remitters showed improved control of blood glucose levels over 14 days within the range of 3.9-10 mmol/l, and lower GRI compared with non-remitters (p<0.001). Moreover, GRI strongly correlated with IDAA1C (r=0.62; p<0.001) and was sufficient to distinguish remitters from non-remitters. Further, four subgroups demonstrating distinct patterns of glycaemic variability associated with different remission status were identified by clustering on CGM metrics: remitters with low risk of dysglycaemia; non-remitters with high risk of hypoglycaemia; non-remitters with high risk of hyperglycaemia; and non-remitters with moderate risk of dysglycaemia. CONCLUSIONS/INTERPRETATION: GRI, an integrative index, together with other traditional CGM metrics, helps to identify different glycaemic variability patterns; this might provide specifically tailored monitoring and management strategies for individuals in the various subclusters.

CXCL12-CXCR4 mediates CD57+ CD8+ T cell responses in the progression of type 1 diabetes.

CD57+ CD8+ T cells, also referred as effector memory cells, are implicated in various conditions including tumor immunity, virus immunity, and most recently with autoimmunity. However, their roles in the progression and remission of T1D are still unclear. Here, we noted an increase in peripheral CD57+ CD8+ T cells in a T1D patient harboring an activator of transcription 3 (STAT3) mutation. Our in-depth study on the role of CD57+ CD8+ T cells within a T1D patient cohort revealed that these cells undergo significant compositional shifts during the disease's progression. Longitudinal cohort data suggested that CD57+ CD8+ T cell prevalence may be a harbinger of ß-cell function decline in T1D patients. Characterized by robust cytotoxic activity, heightened production of pro-inflammatory cytokines, and increased intracellular glucose uptake, these cells may be key players in the pathophysiology of T1D. Moreover, in vitro assays showed that the CXCL12-CXCR4 axis promotes the expansion and function of CD57+ CD8+ T cells via Erk1/2 signaling. Notably, the changes of serum CXCL12 concentrations were also found in individuals during the peri-remission phase of T1D. Furthermore, treatment with the CXCR4 antagonist LY2510924 reduced the immunological infiltration of CD57+ CD8+ T cells and mitigated hyperglycemia in a STZ-induced T1D mouse model. Taken together, our work has uncovered a novel role of the CXCL12-CXCR4 axis in driving CD57+ CD8+ T cells responses in T1D, and presented a promising therapeutic strategy for delaying the onset and progression of diabetes.

Apple Glycosyltransferase MdUGT73AR4 Glycosylates ABA to Regulate Stomatal Movement Involved in Drought Stress.

Abscisic acid (ABA) is a drought-stress-responsive hormone that plays an important role in the stomatal activity of plant leaves. Currently, ABA glycosides have been identified in apples, but their glycosyltransferases for glycosylation modification of ABA are still unidentified. In this study, the mRNA expression of glycosyltransferase gene MdUGT73AR4 was significantly up-regulated in mature apple leaves which were treated in drought stress by Real-Time PCR. It was hypothesised that MdUGT73AR4 might play an important role in drought stress. In order to further characterise the glycosylation modification substrate of glycosyltransferase MdUGT73AR4, we demonstrated through in vitro and in vivo functional validation that MdUGT73AR4 can glycosylate ABA. Moreover, the overexpression lines of MdUGT73AR4 significantly enhance its drought stress resistance function. We also found that the adversity stress transcription factor AREB1B might be an upstream transcription factor of MdUGT73AR4 by bioinformatics, EMSA, and ChIP experiments. In conclusion, this study found that the adversity stress transcription factor AREB1B was significantly up-regulated at the onset of drought stress, which in turn positively regulated the downstream glycosyltransferase MdUGT73AR4, causing it to modify ABA by mass glycosylation and promoting the ABA synthesis pathway, resulting in the accumulation of ABA content, and displaying a stress-resistant phenotype.

Influence of muscle activation on lumbar injury under a specific +Gz load.

PURPOSE: The present study aimed to analyze the influence of muscle activation on lumbar injury under a specific +Gz load. METHODS: A hybrid finite element human body model with detailed lumbar anatomy and lumbar muscle activation capabilities was developed. Using the specific +Gz loading acceleration as input, the kinematic and biomechanical responses of the occupant's lower back were studied for both activated and deactivated states of the lumbar muscles. RESULTS: The results indicated that activating the major lumbar muscles enhanced the stability of the occupant's torso, which delayed the contact between the occupant's head and the headrest. Lumbar muscle activation led to higher strain and stress output in the lumbar spine under +Gz load, such as the maximum Von Mises stress of the vertebrae and intervertebral discs increased by 177.9% and 161.8%, respectively, and the damage response index increased by 84.5%. CONCLUSION: In both simulations, the occupant's risk of lumbar injury does not exceed 10% probability. Therefore, the activation of muscles could provide good protection for maintaining the lumbar spine and reduce the effect of acceleration in vehicle travel direction.

Recovery of intracellular glucose uptake in T cells during partial remission of type 1 diabetes.

AIMS/HYPOTHESIS: Notwithstanding the irreversible beta cell failure seen in type 1 diabetes, some individuals may experience a special phase named 'partial remission' or 'the honeymoon period', in which there is a transient recovery of beta cell function. Importantly, this stage of partial remission shows spontaneous immune downregulation, although the exact mechanisms are unclear. Intracellular energy metabolism is crucial for the differentiation and function of T cells, and provides promising targets for immunometabolic intervention strategies, but its role during partial remission is unknown. In this study, we aim to investigate the association between T cell intracellular glucose and fatty acid metabolism and the partial remission phase. METHODS: This is a cross-sectional study with a follow-up component. Intracellular uptake of glucose and fatty acids by T cells was detected in participants with either new-onset type 1 diabetes or type 1 diabetes that was already in partial remission, and compared with heathy individuals and participants with type 2 diabetes. Subsequently, the participants with new-onset type 1 diabetes were followed up to determine whether they experienced a partial remission (remitters) or not (non-remitters). The trajectory of changes in T cell glucose metabolism was observed in remitters and non-remitters. Expression of programmed cell death-1 (PD-1) was also analysed to investigate possible mechanisms driving altered glucose metabolism. Partial remission was defined when patients had convalescent fasting or 2 h postprandial C-peptide >300 pmol/l after insulin treatment. RESULTS: Compared with participants with new-onset type 1 diabetes, intracellular glucose uptake by T cells decreased significantly in individuals with partial remission. The trajectory of these changes during follow-up showed that intracelluar glucose uptake in T cells fluctuated during different disease stages, with a decreased uptake during partial remission that rebounded after remission. This dynamic in T cell glucose uptake was only detected in remitters and not in non-remitters. Further analysis demonstrated that changes of intracellular glucose uptake were found in subsets of CD4+ and CD8+ T cells, including Th17, Th1, CD8+ naive T cells (Tn) and CD8+ terminally differentiated effector memory T cells (Temra). Moreover, glucose uptake in CD8+ T cells was negatively related to PD-1 expression. The intracellular metabolism of fatty acids was not found to be different between new-onset participants and those in partial remission. CONCLUSIONS/INTERPRETATION: Intracellular glucose uptake in T cells was specifically decreased during partial remission in type 1 diabetes and may be related to PD-1 upregulation, which may be involved in the down-modulation of immune responses during partial remission. This study suggests that altered immune metabolism could be a target for interventions at the point of diagnosis of type 1 diabetes.

Diphenyl Ether Derivatives as Novel GPR120 Agonists for the Treatment of Type 2 Diabetes Mellitus.

Diabetes mellitus (DM) is a serious disease affecting human health. Numerous attempts have been made to develop safe and effective new antidiabetic drugs. Recently, a series of G protein-coupled receptors for free fatty acids (FFAs) have been described and characterized, and small molecule agonists and antagonists of these receptors show considerable promise for managing diabetes and related complications. FFA-activated GPR120 could stimulate the release of glucagon-like peptide-1(GLP-1), which can enhance the glucose-dependent secretion of insulin from pancreatic ß cells. GPR120 is a promising target for treating type 2 DM (T2DM). Herein we designed and synthesized a series of novel GPR120 agonists based on the structure of TUG-891, which was the first potent and selective GPR120 agonist. Among the designed compounds, 18 f showed excellent GPR120 activation activity and high selectivity for GPR40 in vitro. Compound 18 f dose-dependently improved glucose tolerance in normal mice, and no hypoglycemic side effects were observed at high dose. In addition, compound 18 f increased insulin release and displayed good antidiabetic effect in diet-induced obese mice. Molecular simulations illustrated that compound 18 f could enter the active site of GPR120 and interact with Arg99. Based on these observations, compound 18 f may be a promising lead compound for the design of novel GPR120 agonists to treat T2DM.

[The study on the characteristics of active force of neck muscles under rapid braking conditions].

This paper studies the active force characteristics of the neck muscles under the condition of rapid braking, which can provide theoretical support for reducing the neck injury of pilots when carrier-based aircraft blocks the landing. We carried out static loading and real vehicle braking experiments under rapid braking conditions, collected the active contraction force and electromyography (EMG) signals of neck muscles, and analyzed the response characteristics of neck muscle active force response. The results showed that the head and neck forward tilt time was delayed and the amplitude decreased during neck muscle pre-tightening. The duration of the neck in the extreme position decreased, and the recovery towards the seat direction was faster. The EMG signals of trapezius muscle was higher than sternocleidomastoid muscle. This suggests that pilots can reduce neck injury by pre-tightening the neck muscles during actual braking flight. In addition, we can consider the design of relevant fittings for pre-tightening the neck muscles.

Identification and functional characterization of a new flavonoid synthase gene MdFLS1 from apple.

MAIN CONCLUSION: The flavonoid synthase gene MdFLS1 from apple, which possibly plays an important role in anthocyanin synthesis, accumulates in the purple-red branches of Malus 'Pink spire'. Flavonoid metabolism serves an important function in plant growth and development. In this study, we selected 20 varieties of apple lines, 10 green and ten red branches, from the plant nursery of Qingdao Agriculture Academy. Metabolite analysis revealed that large amounts of anthocyanins accumulated in the purple-red branches of M. 'Pink spire'. Real-time polymerase chain reaction showed that the expression of the flavonol synthase gene MdFLS1 was over 1500-fold higher in M. 'Pink spire' than in the other varieties. A single base A was inserted at the first three bases of the active binding site of MdFLS1 to prove that the purple-red colour of apple leaves and stems in M. 'Pink spire' may be caused by the inactivation of MdFLS1 protein. The results of in vitro enzymatic reaction revealed that the MdFLS1 protein lost its activity. MdFLS1 was expressed in Arabidopsis thaliana to explore further its functions. High-expression wild-type strains (OE1 and OE2) and high-expression strains of A-base insertion (A-OE1 and A-OE2) were obtained. Compared with the wild-type strains, the overexpression lines showed lighter tissue colour and less accumulation of anthocyanins. However, A-OE1 and A-OE2 showed no difference in colouration. In conclusion, we speculated that the MdFLS1 gene in M. 'Pink spire' cannot bind flavonoids, triggering the synthesis of anthocyanins in another branch of the flavonoid metabolic pathway and resulting in the purple-red colouration of apple leaves and stems. These results suggest that MdLS1 is a potential genetic target for breeding high-flavonoid apples in future cultivar development.

Design, Synthesis, and In Vivo and In Silico Evaluation of Coumarin Derivatives with Potential Antidepressant Effects.

In this study, a series of coumarin derivatives were designed and synthesized, their structures were characterized using nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS) testing methods. In the pharmacological experiment, two behavior-monitoring methods, the forced swim test (FST) and the tail suspension test (TST), were used to determine the antidepressant activity of coumarin derivatives. Compounds that showed potential activity were analyzed for their effects on 5-hydroxytryptamine (5-HT) levels in the brains of mice. Molecular docking experiments to simulate the possible interaction of these compounds with the 5-HT1A receptor was also be predicted. The results of the pharmacological experiments showed that most coumarin derivatives exhibited significant antidepressant activity. Among these compounds, 7-(2-(4-(4-fluorobenzyl)piperazin-1-yl)-2-oxoethoxy)-2H-chromen-2-one (6i) showed the highest antidepressant activity. The results of the measurement of 5-HT levels in the brains of mice indicate that the antidepressant activity of coumarin derivatives may be mediated by elevated 5-HT levels. The results of molecular docking demonstrated that compound 6i had a significant interaction with amino acids around the active site of the 5-HT1A receptor in the homology model. The physicochemical and pharmacokinetic properties of the target compounds were also predicted using Discovery Studio (DS) 2020 and Chemdraw 14.0.

Novel GPR120 Agonists with Improved Pharmacokinetic Profiles for the Treatment of Type 2 Diabetes.

GPR120 is a promising target for the treatment of type 2 diabetes (T2DM), which is activated by free fatty acids (FFAs) and stimulates the release of glucagon-like peptide-1(GLP-1). GLP-1, as an incretin, can enhance glucose-dependent secretion of insulin from pancreatic beta cells and reduce blood glucose. In this study, a series of novel GPR120 agonists were designed and synthesized to improve the stability and hydrophilicity of the phenylpropanoic acid GPR120 agonist TUG-891. Compound 11b showed excellent GPR120 agonistic activity and pharmacokinetic properties, and could reduce the blood glucose of normal mice in a dose-dependent manner. In addition, no hypoglycemic side effects were observed even at a dose of 100 mg/kg. Moreover, 11b showed good anti-hyperglycemic effects in diet-induced obese (DIO) mice. Molecular simulation illustrated that compound 11b could enter the active site of GPR120 and interact with ARG99. Taken together, the results indicate that compound 11b might be a promising drug candidate for the treatment of T2DM.

Synthesis of 3,4-dihydroquinolin-2(1H)-one derivatives with anticonvulsant activity and their binding to the GABAA receptor.

In this study, a series of 3,4-dihydroquinolin-2(1H)-one derivatives were designed and synthesized using two experimental models, namely maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ), to test the anticonvulsant activity of the target compound in vivo (i.p. in Kunming mice). The neurotoxicity (NT) of the target compound was measured by the rotating rod method (i.p. in Kunming mice). Six compounds with potential activity were selected from the two experimental models to test the 50% effective dose (ED50). In vitro binding experiments with the GABAA receptor were also performed. The results of the pharmacological experiments showed that compound 7-((5-(pentylthio)-1,3,4-oxadiazol-2-yl)methoxy)-3,4-dihydroquinolin-2(1H)-one (5b) showed the best anticonvulsant activity (MES, ED50 = 10.1 mg/kg; scPTZ, ED50 = 9.3 mg/kg), which was superior to activities shown by carbamazepine and ethosuximide, and it also exhibited the most potent binding affinity to GABAA receptors (IC50 = 0.12 µM). The GABA content in Wistar rat brains (i.p.) was also investigated, and the results showed that compound 5b may have a certain effect on the GABA system, as it increased the GABA concentration in the brain of rats. Molecular docking was used to study the binding mode of compound 5b and the GABAA receptor. Compound 5b showed significant interactions with residues at the benzodiazepines binding site on the GABAA receptor. The physicochemical and pharmacokinetic properties of the target compounds were predicted using Discovery Studio 2019 and ChemBioDraw Ultra 14.0.

Design, synthesis and biological evaluation of amide-pyridine derivatives as novel dual-target (SE, CYP51) antifungal inhibitors.

Based on the analysis of the squalene cyclooxygenase (SE) and 14α-demethylase (CYP51) inhibitors pharmacophore feature and the dual-target active sites, a series of compounds with amide-pyridine scaffolds have been designed and synthesized to treat the increasing incidence of drug-resistant fungal infections. In vitro evaluation showed that these compounds have a certain degree of antifungal activity. The most potent compounds 11a, 11b with MIC values in the range of 0.125-2 µg/ml had a broad-spectrum antifungal activity and exhibited excellent inhibitory activity against drug-resistant pathogenic fungi. Preliminary mechanism studies revealed that the compound 11b might play an antifungal role by inhibiting the activity of SE and CYP51. Notably compounds did not show the genotoxicity through plasmid binding assay. Finally, this study of molecular docking, ADME/T prediction and the construction of 3D QSAR model were performed. These results can point out the direction for further optimization of the lead compound.

Synthesis and evaluation of anticonvulsant activities of 7-phenyl-4,5,6,7-tetrahydrothieno[3,2-b ]pyridine derivatives.

A series of 7-phenyl-4,5,6,7-tetrahydrothieno[3,2-b]pyridine derivatives containing triazole and other heterocycle substituents (methyltriazole, tetrazole, and triazolone) is described. Two experimental methods, maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ), were used to evaluate the anticonvulsant activity of the target compounds. Moreover, the neurotoxicity (NT) was tested using the Rotarod test. 5-(4-Chlorophenyl)-4,5-dihydrothieno[2,3-e][1,2,4]triazolo[4,3-a]pyridine (6c) showed the best anticonvulsant activity. In the MES and PTZ experiments, the 50% effective dose (ED50 ) values of compound 6c were 9.5 and 20.5 mg/kg, respectively. From the therapeutic index (PI) values, 6c (MES and PTZ with PI values of 48.0 and 22.2, respectively) showed better safety than the clinical drugs carbamazepine (MES with PI value of 6.4) and ethosuximide (PTZ with PI value of 3.2). The biological activities of the compounds were verified by using molecular docking studies. Compound 6c showed significant interactions with residues at the benzodiazepine-binding site on gamma-aminobutyric acid A (GABAA ) receptors. The results of in vivo GABA estimation and bicuculline-induced seizures showed that 6c may have an effect on the GABA system. The physicochemical and pharmacokinetic properties of the target compounds were predicted.

Synthesis and Evaluation of Antidepressant Activities of 5-Aryl-4,5-dihydrotetrazolo [1,5-a]thieno[2,3-e]pyridine Derivatives.

In this study, we synthetized a series of 5-aryl-4,5-dihydrotetrazolo[1,5-a]thieno[2,3-e]pyridine derivatives containing tetrazole and other heterocycle substituents, i.e., triazole, methyltriazole, and triazolone. The forced swim test (FST) and tail suspension test (TST) were used to evaluate the antidepressant activity of the target compounds. The compound 5-[4-(trifluoromethyl)phenyl]-4,5-dihydrotetrazolo[1,5-a]thieno[2,3-e]pyridine (4i) showed the highest antidepressant activity, with a reduced immobility time of 55.33% when compared with the control group. Using an open-field test, compound 4i was shown to not affect spontaneous activity of mice. The determination of in vivo 5-hydroxytryptamine (5-HT) concentration showed that compound 4i may have an effect in the mouse brain. The biological activities of all synthetized compounds were verified by molecular docking studies. Compound 4i showed significant interactions with residues of the 5-HT1A receptor homology model.

Effect of allelochemical tricin and its related benzothiazine derivative on photosynthetic performance of herbicide-resistant barnyardgrass.

Despite increasing knowledge of allelochemicals as leads for new herbicides, relatively little is known about the mode of action of allelochemical-based herbicides on herbicide-resistant weeds. In this study, herbicidal activities of a series of allelochemical tricin-derived compounds were evaluated. Subsequently, a benzothiazine derivative 3-(2-chloro-4-methanesulfonyl)-benzoyl-hydroxy-2-methyl-2H-1,2-benzothiazine-1,1-dioxide with 4-hydroxyphenyl-pyruvate dioxygenase (HPPD) inhibiting activity was identified as a target compound on photosynthetic performance of penoxsulam-resistant versus -susceptible barnyardgrass (Echinochloa crus-galli). Regardless of barnyardgrass biotype, the benzothiazine derivative greatly affected chlorophyll fluorescence parameters (Fv/Fm, ETR1min and NPQ1min), reduced the chloroplast fluorescence levels and expression of HPPD gene. In particular, the benzothiazine derivative interfered with photosynthetic performance of resistant barnyardgrass more effectively than the allelochemical tricin itself. These results showed that the benzothiazine derivative effectively inhibited the growth of resistant barnyardgrass and its mode of action on photosynthesis system was similar to HPPD-inhibiting sulcotrione, making it an ideal lead compound for further development of allelochemical-based herbicide discovery.

Indium-Mediated Intramolecular Reaction of N-(2-Iodobenzoyl)azabenzonorbornadienes: A General Access to Dihydrobenzo[c]phenanthridinones.

An efficient synthesis of dihydrobenzo[c]phenanthridinones was achieved by utilizing an indium(0)-mediated intramolecular cyclization reaction under ligand- and base-free conditions. A variety of functional groups were tolerated in the present protocol.

Discovery of (2-benzoylethen-1-ol)-containing 1,2-benzothiazine derivatives as novel 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibiting-based herbicide lead compounds.

A series of (2-benzoylethen-1-ol)-containing benzothiazine derivatives was synthesized, and their herbicidal activities were first evaluated. The bioassay results indicated that some of 3-benzoyl-4-hydroxy-2-methyl-2H-1,2-benzothiazine-1,1-dioxide derivatives displayed good herbicidal activity in greenhouse testing, especially, compound 4w had good pre-emergent herbicidal activities against Brassica campestris, Amaranthus retroflexus and Echinochloa crusgalli even at a dosage of 187.5 g ha(-1). More importantly, compound 4w displayed significant inhibitory activity against Arabidopsis thaliana HPPD and was identified as the most potent candidate with IC50 value of 0.48 µM, which is better than the commercial herbicide sulctrione (IC50=0.53 µM) and comparable with the commercial herbicide mesotrione (IC50=0.25 µM). The structure-activity relationships was studied and provided some useful information for improving herbicidal activity. The present work indicated that (2-benzoylethen-1-ol)-containing 1,2-benzothiazine motif could be a potential lead structure for further development of novel HPPD inhibiting-based herbicides.

Effector-triggered and self-regulated plant resistance to insects.

Despite many years of research, the molecular mechanisms underlying the activation and regulation of host plant resistance (HPR) to insects remain elusive. Recently, Guo et al. reported that a nucleotide-binding leucine-rich repeat NLR protein activates HPR through direct recognition of an insect effector and that autophagy-mediated degradation of this effector negatively regulates HPR.

First Clarification of the Mechanism of Action of the Apple Glycosyltransferase MdUGT91AJ2 Involved in the Detoxification Metabolism of the Triketone Herbicide Sulcotrione.

Sulcotrione is a member of triketone herbicides, a class of HPPD (4-hydroxyphenylpyruvate dioxygenase) inhibitors with broad-spectrum herbicidal activity. Modifications of glycosylation mediated by glycosyltransferases (GT) are involved in plant detoxification. In this study, we analyzed chip data published online and found that eight glycosyltransferases from group A of the apple glycosyltransferase family 1 may be involved in the metabolic mechanism of detoxification of triketone herbicides. To verify this prediction, we induced apple seedlings with six types of triketone herbicides, and then detected the expression levels of eight glycosyltransferase genes through real-time PCR. We found that triketone herbicides induced up-regulation of eight glycosyltransferase genes to varying degrees, with MdUGT91AJ2 being the most significantly up-regulated by sulcotrione-induced glycosyltransferase gene expression. Then, through in vitro enzymatic reactions and HPLC identification of glycoside substrates, it was found that the glycosyltransferase MdUGT91AJ2 had the highest specific enzyme activity against the triketone herbicide sulcotrione. Furthermore, the in vivo mechanism of the glycosyltransferase MdUGT91AJ2 in the detoxification metabolism of sulcotrione was further validated by overexpressing the strain in the plant. HPLC analysis showed that the content of sulcotrione glycosides in the overexpressing strain of MdUGT91AJ2 was significantly higher than that in the wild type. This result indicated that the apple glycosyltransferase MdUGT91AJ2 can still glycosylate and modify sulfotrione in plants, and participate in its detoxification metabolism. In summary, this study identified for the first time a novel apple glycosyltransferase MdUGT91AJ2 and elucidated its mechanism of action in the detoxification and metabolism of the triketone herbicide sulfotriene.

First Clarification of the Involvement of Glycosyltransferase MdUGT73CG22 in the Detoxification Metabolism of Nicosulfuron in Apple.

Nicosulfuron, an acetolactate synthase (ALS) inhibitor herbicide, is a broad-spectrum and highly effective post-emergence herbicide. Glycosyltransferases (GTs) are widely found in organisms and transfer sugar molecules from donors to acceptors to form glycosides or sugar esters, thereby altering the physicochemical properties of the acceptor molecule, such as participating in detoxification. In this study, nine glycosyltransferases in group D of the apple glycosyltransferase family I were predicted to possibly be involved in the detoxification metabolism of ALS-inhibiting herbicides based on gene chip data published online. In order to confirm this, we analysed whether the expression of the nine glycosyltransferase genes in group D was induced by the previously reported ALS-inhibiting herbicides by real-time PCR (polymerase chain reaction). It was found that the ALS-inhibiting herbicide nicosulfuron significantly increased the expression of the MdUGT73CG22 gene in group D. Further investigation of the mechanism of action revealed that the apple glycosyltransferase MdUGT73CG22 glycosylated and modified nicosulfuron both in vivo and ex vivo to form nicosulfuron glycosides, which were involved in detoxification metabolism. In conclusion, a new glycosyltransferase, MdUGT73CG22, was identified for the first time in this study, which can glycosylate modifications of the ALS-inhibiting herbicide nicosulfuron and may be involved in the detoxification process in plants, which can help to further improve the knowledge of the non-targeted mechanism of herbicides.