Clinical metabolomics characteristics of diabetic kidney disease: A meta-analysis of 1875 cases with diabetic kidney disease and 4503 controls.

AIMS: Diabetic Kidney Disease (DKD), one of the major complications of diabetes, is also a major cause of end-stage renal disease. Metabolomics can provide a unique metabolic profile of the disease and thus predict or diagnose the development of the disease. Therefore, this study summarises a more comprehensive set of clinical biomarkers related to DKD to identify functional metabolites significantly associated with the development of DKD and reveal their driving mechanisms for DKD. MATERIALS AND METHODS: We searched PubMed, Embase, the Cochrane Library and Web of Science databases through October 2022. A meta-analysis was conducted on untargeted or targeted metabolomics research data based on the strategy of standardized mean differences and the process of ratio of means as the effect size, respectively. We compared the changes in metabolite levels between the DKD patients and the controls and explored the source of heterogeneity through subgroup analyses, sensitivity analysis and meta-regression analysis. RESULTS: The 34 clinical-based metabolomics studies clarified the differential metabolites between DKD and controls, containing 4503 control subjects and 1875 patients with DKD. The results showed that a total of 60 common differential metabolites were found in both meta-analyses, of which 5 metabolites (p < 0.05) were identified as essential metabolites. Compared with the control group, metabolites glycine, aconitic acid, glycolic acid and uracil decreased significantly in DKD patients; cysteine was significantly higher. This indicates that amino acid metabolism, lipid metabolism and pyrimidine metabolism in DKD patients are disordered. CONCLUSIONS: We have identified 5 metabolites and metabolic pathways related to DKD which can serve as biomarkers or targets for disease prevention and drug therapy.

Study of aerosol dispersion and control in dental practice.

OBJECTIVES: In this study, we investigated the dispersion patterns of aerosols and droplets in dental clinics and developed a suction device to evaluate its effectiveness in reducing aerosols during dental procedures. MATERIALS AND METHODS: Firstly, the continuous images of oral aerosols and droplets were photographed with a high-speed camera, and the trajectories of these particles were recognized and processed by Image J to determine key parameters affecting particle dispersion: diffusion velocity, distance, and angle. Secondly, based on the parameter data, the flow field of aerosol particles around the oral cavity was simulated using computational fluid dynamics (CFD), and the flow field under adsorption conditions was simulated to demonstrate the aerodynamic characteristics and capture efficiencies of the single-channel and three-channel adsorption ports at different pressures. Finally, according to the simulated data, a three-channel suction device was developed, and the capture efficiency of the device was tested by the fluorescein tracer method. RESULTS: The dispersion experimental data showed that aerosol particles' maximum diffusion velocity, distance, and angle were 6.2 m/s, 0.55 m, and 130°, respectively. The simulated aerosol flow-field distribution was consistent with the aerosol dispersion patterns. The adsorption simulation results showed that the outlet flow rate of single-channel adsorption was 184.5 L/s at - 350 Pa, and the aerosol capture efficiency could reach 79.4%. At - 350 Pa and - 150 Pa, the outlet flow rate of three-channel adsorption was 228.9 L/s, and the capture efficiency was 99.23%. The adsorption experimental data showed that the capture efficiency of three-channel suction device was 97.71%. CONCLUSIONS: A three-channel suction device was designed by simulations and experiments, which can capture most aerosols in the dental clinic and prevent them from spreading. CLINICAL RELEVANCE: Using three-channel suction devices during oral treatment effectively reduces the spread of oral aerosols, which is essential to prevent the spread of epidemics and ensure the health and safety of patients and dental staff.

Ultrafast Laser Pulse Induced Transient Ferrimagnetic State and Spin Relaxation Dynamics in Two-Dimensional Antiferromagnets.

We employ real-time time-dependent density functional theory (rt-TDDFT) and ab initio nonadiabatic molecular dynamics (NAMD) to systematically investigate the ultrafast laser pulses induced spin transfer and relaxation dynamics of two-dimensional (2D) antiferromagnetic-ferromagnetic (AFM/FM) MnPS3/MnSe2 van der Waals heterostructures. We demonstrate that laser pulses can induce a ferrimagnetic (FiM) state in the AFM MnPS3 layer within tens of femtoseconds and maintain it for subpicosecond time scale before reverting to the AFM state. We identify the mechanism in which the asymmetric optical intersite spin transfer (OISTR) effect occurring within the sublattices of the AFM and FM layers drives the interlayer spin-selective charge transfer, leading to the transition from AFM to FiM state. Furthermore, the unequal electron-phonon coupling of spin-up and spin-down channels of AFM spin sublattice causes an inequivalent spin relaxation, in turn extending the time scale of the FiM state. These findings are essential for designing novel optical-driven ultrafast 2D magnetic switches.

Ultrafast Laser Control of Antiferromagnetic-Ferrimagnetic Switching in Two-Dimensional Ferromagnetic Semiconductor Heterostructures.

Realizing ultrafast control of magnetization switching is of crucial importance for information processing and recording technology. Here, we explore the laser-induced spin electron excitation and relaxation dynamics processes of CrCl3/CrBr3 heterostructures with antiparallel (AP) and parallel (P) systems. Although an ultrafast demagnetization of CrCl3 and CrBr3 layers occurs in both AP and P systems, the overall magnetic order of the heterostructure remains unchanged due to the laser-induced equivalent interlayer spin electron excitation. More crucially, the interlayer magnetic order switches from antiferromagnetic (AFM) to ferrimagnetic (FiM) in the AP system once the laser pulse disappears. The microscopic mechanism underpinning this magnetization switching is dominated by the asymmetrical interlayer charge transfer combined with a spin-flip, which breaks the interlayer AFM symmetry and ultimately results in an inequivalent shift in the moment between two FM layers. Our study opens up a new idea for ultrafast laser control of magnetization switching in two-dimensional opto-spintronic devices.

msQSM: Morphology-based self-supervised deep learning for quantitative susceptibility mapping.

Quantitative susceptibility mapping (QSM) has been applied to the measurement of iron deposition and the auxiliary diagnosis of neurodegenerative disease. There still exists a dipole inversion problem in QSM reconstruction. Recently, deep learning approaches have been proposed to resolve this problem. However, most of these approaches are supervised methods that need pairs of the input phase and ground-truth. It remains a challenge to train a model for all resolutions without using the ground-truth and only using one resolution data. To address this, we proposed a self-supervised QSM deep learning method based on morphology. It consists of a morphological QSM builder to decouple the dependency of the QSM on acquisition resolution, and a morphological loss to reduce artifacts effectively and save training time efficiently. The proposed method can reconstruct arbitrary resolution QSM on both human data and animal data, regardless of whether the resolution is higher or lower than that of the training set. Our method outperforms the previous best unsupervised method with a 3.6% higher peak signal-to-noise ratio, 16.2% lower normalized root mean square error, and 22.1% lower high-frequency error norm. The morphological loss reduces training time by 22.1% with respect to the cycle gradient loss used in the previous unsupervised methods. Experimental results show that the proposed method accurately measures QSM with arbitrary resolutions, and achieves state-of-the-art results among unsupervised deep learning methods. Research on applications in neurodegenerative diseases found that our method is robust enough to measure significant increase in striatal magnetic susceptibility in patients during Alzheimer's disease progression, as well as significant increase in substantia nigra susceptibility in Parkinson's disease patients, and can be used as an auxiliary differential diagnosis tool for Alzheimer's disease and Parkinson's disease.

A meta-analysis of treatment for early-stage cervical cancer: open versus minimally invasive radical trachelectomy.

BACKGROUND: In previous systematic reviews, meta-analysis was lacking, resulting in the statistical difference between the data of different surgeries being impossible to judge. This meta-analysis aims to contrast the fertility results and cancer outcomes between open and minimally invasive surgery. METHOD: We systematically searched databases including PubMed, Embase, Cochrane, and Scopus to collect studies that included open and minimally invasive radical trachelectomy. A random-effect model calculated the weighted average difference of each primary outcome via Review Manager V.5.4. RESULT: Eight studies (1369 patients) were incorporated into our study. For fertility results, the Open group excels MIS group in pregnancies-Third trimester delivery [OR = 2.68; 95% CI (1.29, 5.59); P = 0.008]. Nevertheless, there is no statistical difference in clinical pregnancy, miscarriage, and second-trimester rate. Concerning cancer outcomes, no difference was detected in the overall survival [OR = 1.56; 95% CI (0.70, 3.45); P = 0.27] and recurrence [OR = 0.63; 95% CI (0.35, 1.12); P = 0.12]. Concerning surgery-related outcomes, the comprehensive effects revealed that the estimated blood loss of the Open group was higher than that of the MIS group[MD = 139.40; 95% CI (79.05, 199.75); P < 0.0001]. However, there was no difference between the postoperative complication rate in the two groups [OR = 1.52; 95% CI (0.89, 2.60); P = 0.12]. CONCLUSION: This meta-analysis suggested that the fertility result of the Open group may be better than the MIS group, while the MIS group has better surgery-related outcomes. Owing to the poor cases of our study, a more robust conclusion requires more relevant articles in the future. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022352999.

Two Dimensional MOene: From Superconductors to Direct Semiconductors and Weyl Fermions.

The number of semiconducting MXenes with direct band gaps is extremely low; thus, it is highly desirable to broaden the MXene family beyond carbides and nitrides to expand the palette of desired chemical and physical properties. Here, we theoretically report the existence of the single-layer (SL) dititanium oxide 2H-Ti2O MOene (MXene-like 2D transition oxides), showing an Ising superconducting feature. Moreover, SL halogenated 2H- and 1T-Ti2O monolayers display tunable semiconducting features and strong light-harvesting ability. In addition, the external strains can induce Weyl fermions via quantum phase transition in 2H-Ti2OF2 and Ti2OCl2 monolayers. Specifically, 2H- and 1T-Ti2OF2 are direct semiconductors with band gaps of 0.82 and 1.18 eV, respectively. Furthermore, the carrier lifetimes of SL 2H- and 1T-Ti2OF2 are evaluated to be 0.39 and 2.8 ns, respectively. This study extends emerging phenomena in a rich family of 2D MXene-like MOene materials, which provides a novel platform for next-generation optoelectronic and photovoltaic fields.

The Evolution of Single-Cell RNA Sequencing Technology and Application: Progress and Perspectives.

As an emerging sequencing technology, single-cell RNA sequencing (scRNA-Seq) has become a powerful tool for describing cell subpopulation classification and cell heterogeneity by achieving high-throughput and multidimensional analysis of individual cells and circumventing the shortcomings of traditional sequencing for detecting the average transcript level of cell populations. It has been applied to life science and medicine research fields such as tracking dynamic cell differentiation, revealing sensitive effector cells, and key molecular events of diseases. This review focuses on the recent technological innovations in scRNA-Seq, highlighting the latest research results with scRNA-Seq as the core technology in frontier research areas such as embryology, histology, oncology, and immunology. In addition, this review outlines the prospects for its innovative application in traditional Chinese medicine (TCM) research and discusses the key issues currently being addressed by scRNA-Seq and its great potential for exploring disease diagnostic targets and uncovering drug therapeutic targets in combination with multiomics technologies.

Control of Hot Carrier Cooling in Lead Halide Perovskites by Point Defects.

Hot carriers (HCs) in lead halide perovskites are prone to rapidly relax at the band edge and waste plentiful photon energy, severely limiting their conversion efficiency as HC photovoltaic devices. Here, the HC cooling dynamics of MAPbI3 perovskite with common vacancy point defects (e.g., MAv+ and Iv-) and an interstitial point defect (e.g., Ii-) is elucidated, and the underlying physics is explicated using ab initio nonadiabatic molecular dynamics. Contrary to vacancy point defects, the interstitial point defect reduces the band degeneracy, decreases the HC -phonon interaction, weakens the nonadiabatic coupling, and ultimately slows down hot electron cooling by a factor of 1.5-2. Furthermore, the band-by-band relaxation pathway and direct relaxation pathway are uncovered for hot electron cooling and hot hole cooling, respectively, explaining why hot electrons can store more energy than hot holes during the cooling process. Besides, oxygen molecules interacting with Ii- sharply accelerate the hot electron cooling, making it even faster than that of the pristine system and revealing the detrimental effect of oxygen on HC cooling. This work provides significant insights into the defect-dependent HC cooling dynamics and suggests a new strategy to design high-efficiency HC photovoltaic devices.

Outcomes of minimally invasive total mesoesophageal excision: a propensity score-matched analysis.

BACKGROUND: This study aimed to investigate the safety and efficacy of minimally invasive total mesoesophageal excision (TME) for esophageal cancer. METHODS: We retrospectively collected data from patients with esophageal cancer who underwent esophagectomy at our center between January 2011 and June 2017. Among 611 eligible patients, 302 underwent minimally invasive total mesoesophageal excision (the TME group) and 309 underwent non-total mesoesophageal excision (the NME group). Outcomes were compared after 1-to-1 propensity score matching, and subgroup analyses were performed for cases involving pT1-2 or pT3-4a disease. RESULTS: The propensity score matching produced 249 pairs of patients. The TME group had a shorter operative time (P < 0.001), lower intraoperative bleeding (P < 0.001), and a shorter postoperative hospital stay (P < 0.001). There were no significant differences between the two groups in the number of removed lymph nodes, 30-day mortality, or postoperative complications. In addition, both groups had similar 3-year rates of overall survival (OS) and disease-free survival (DFS). However, the 3-year recurrence rate in the esophageal bed was significantly lower in the TME group (P = 0.033). Furthermore, among patients with pT3-4a disease, the TME group had better 3-year rates of OS, DFS, and recurrence. CONCLUSION: Minimally invasive total mesoesophageal excision appears to be a safe technique that can reduce tumor recurrence in the esophageal bed. Furthermore, this technique provided survival benefits for patients with pT3-4a disease.

Magnesium hydride confers copper tolerance in alfalfa via regulating nitric oxide signaling.

Magnesium hydride (MgH2) as a solid-state hydrogen source might be potentially applied in industry and medicine. However, its biological function in plants has not yet been fully discovered. In this report, it was observed that MgH2 administration could relieve copper (Cu) toxicity in alfalfa that was confirmed by a reduction in root growth inhibition. By using old MgH2 as a negative control, it was concluded that above MgH2 function was primarily derived from the releasing of molecular hydrogen (H2), but not caused by either magnesium metabolites or pH alteration. Further results revealed that Cu-triggered nitric oxide (NO) production was intensified by MgH2. Subsequent pharmacological and biochemical experiments suggested that nitrate reductase might be mainly responsible for NO production during above processes. Cu accumulation in the root tissues was also obviously reduced in the presence of MgH2. Meanwhile, increased non-protein thiols (NPTs) content and the deposition of Cu in cell wall of seedling roots could be used to explain the mechanism underlying MgH2-alleviated Cu toxicity via NO signaling. Further, the plant redox balance was reestablished since the Cu stress-modulated antioxidant enzymes activities, reactive oxygen species (ROS) accumulation, and oxidative injury detected by in vivo histochemical and biochemical analyses, were differentially abolished by MgH2. The above responses could be blocked by the removal of endogenous NO after the addition of its scavenger. Taken together, these results clearly suggested that MgH2 control of plant tolerance against Cu toxicity might be mediated by NO signaling, which might open a new window for the application of solid-state hydrogen materials in agriculture.

Unravelling Photoinduced Interlayer Spin Transfer Dynamics in Two-Dimensional Nonmagnetic-Ferromagnetic van der Waals Heterostructures.

Although light is the fastest means to manipulate the interfacial spin injection and magnetic proximity related quantum properties of two-dimensional (2D) magnetic van der Waals (vdW) heterostructures, its potential remains mostly untapped. Here, inspired by the recent discovery of 2D ferromagnets Fe3GeTe2 (FGT), we applied the real-time density functional theory (rt-TDDFT) to study photoinduced interlayer spin transfer dynamics in 2D nonmagnetic-ferromagnetic (NM-FM) vdW heterostructures, including graphene-FGT, silicene-FGT, germanene-FGT, antimonene-FGT and h-BN-FGT interfaces. We observed that laser pulses induce significant large spin injection from FGT to nonmagnetic (NM) layers within a few femtoseconds. In addition, we identified an interfacial atom-mediated spin transfer pathway in heterostructures in which the photoexcited spin of Fe first transfers to intralayered Te atoms and then hops to interlayered NM layers. Interlayer hopping is approximately two times slower than intralayer spin transfer. Our results provide the microscopic understanding for optically control interlayer spin dynamics in 2D magnetic heterostructures.

Ni/Mo Bimetallic-Oxide-Derived Heterointerface-Rich Sulfide Nanosheets with Co-Doping for Efficient Alkaline Hydrogen Evolution by Boosting Volmer Reaction.

Molybdenum disulfide (MoS2 ) is a promising alternative to Pt-based catalysts for electrocatalytic hydrogen evolution reaction (HER) in an acidic environment. However, alkaline HER activity for molybdenum disulfide is limited by its slow water dissociation kinetics. Interface engineering is an effective strategy for the design of alkaline HER catalysts. However, the restricted heterointerfaces of current catalysts have significantly limited their alkaline HER performance. Herein, a novel assembly of cobalt-doped interface- and defect-rich MoS2 /Ni3 S2 hetero-nanosheet anchoring on hierarchical carbon framework for alkaline HER is reported by directly vulcanizing NiMoO4 nanosheets. In the heterostructure nanosheet, Ni3 S2 acts as a water dissociation promoter and MoS2 acts as a hydrogen acceptor. Density functional theory calculations find that redistribution of charges at the heterointerface can reduce hydrogen adsorption Gibbs free energy (∆GH* ) and water decomposition energy barrier. The resulting hierarchical electrode with the synergistic effect of both hybrid components shows a low overpotential of 89 mV at -10 mA cm-2 in 1 m KOH, a Tafel slope as low as 62 mV dec-1 , and can run at -100 mA cm-2 for at least 50 h without obvious voltage change. This study provides a potentially feasible strategy for the design of heterostructure-based electrocatalysts with abundant active interfaces.

Clinical and genetic features of somatic mosaicism in facioscapulohumeral dystrophy.

PURPOSE: To analyse the clinical spectrum, genetic features, specific D4Z4 hypomethylation status and genotype-phenotype correlations for somatic mosaicism in facioscapulohumeral dystrophy (FSHD). METHODS: This was a prospective, hospital-based, case-control, observational study of 35 participants with FSHD with somatic mosaicism recruited over 10 years, with 17 penetrant patients and 18 non-penetrant mutation carriers. This study also included a univariate comparison of 17 paired mosaic and non-mosaic patients with FSHD. RESULTS: Mosaic participants with FSHD varied in age of diagnosis (median 45; range 15-65 years), muscle strength (FSHD clinical score median 0; range 0-10 points), clinical severity (age-corrected clinical severity score (ACSS) median 0; range 0-467 points), D4Z4 repeats (median 3; range 2-5 units), mosaic proportion (median 55%; range 27%-72%) and D4Z4 methylation extent (median 49.82%; range 27.17%-64.51%). The genotypic severity scale and D4Z4 methylation extent were significantly associated with ACSS (p1=0.003; p2=0.002). Among the matched pairs, the 17 mosaic patients had shorter D4Z4 repeats, lower FSHD clinical scores and lower ACSS than non-mosaic patients. Additionally, 34 of 35 (97%) participants carried two mosaic arrays, while a single patient had three mosaic arrays (3%). Two cases also carried four-type non-mosaic arrays on chromosome 10 (translocation configuration). CONCLUSIONS: Broadly, this large mosaic FSHD cohort exhibited significant clinical heterogeneity and relatively slight disease severity. Both genotypic severity scale and D4Z4 hypomethylation status served as modifiers of clinical phenotypes. Consistent with previous reports, mitotic interchromosomal/intrachromosomal gene conversion without crossover was here identified as a major genetic mechanism underlying mosaic FSHD.

Graphene metalens with dynamic focusing and plane focusing in the terahertz range.

We theoretically propose a high-efficiency tunable metalens based on an ellipse-shaped perforated graphene metasurface. By optimizing the axial length ratio of the elliptical aperture, we find the elliptical aperture with high reflectivity over a broad band by means of observing the reflectivity at different frequencies. Then, varying the orientation of the elliptical aperture from 0° to 180°, the reflected wave can generate a continuous 2π range phase shift while keeping its amplitude high, which is necessary to achieve focusing. The metalens exhibits extraordinary tunability of focal length via uniformly changing the Fermi energy of graphene. The focus can be shifted above 72 µm with focusing efficiency reaching over 70%. In addition, the tunable metalens is also capable of broadband focusing modulation and plane focusing. The presented metalens exhibits outstanding focusing efficiency in dynamic focusing, thereby manifesting great practicability in dynamic imaging and robust stable imaging.

Propagation of Pearcey Gaussian beams in a strongly nonlocal nonlinear medium.

We introduce the propagation of Pearcey Gaussian (PG) beams in a strongly nonlocal nonlinear medium (SNNM) analytically. Our results show that PG beams propagating in the SNNM have two different focusing positions. The intensity peak appears at different focusing positions depending on the selection of the nonlinear parameters. In addition, the effects of the nonlinear parameters and the scaling factor on the trajectory, the position of the intensity focusing, the intensity evolution between focus locations, and the radiation force are studied.

Magnon-phonon interaction in antiferromagnetic two-dimensional MXenes.

Antiferromagnetic material possesses excellent robustness to an external magnetic field perturbation, which makes it promising in application of spintronic devices. The magnon-phonon interaction plays a vital role in spintronic devices. In this work, we performed first-principles calculation to study the effect of magnon-phonon interaction on magnon spectra of the antiferromagnetic MXenes Cr2TiC2FCl, and calculated the phonon dominated magnon relaxation time based on the magnon spectra broadening. Due to the large exchange constants across Cr-Cr pairs, high magnon energy is found in Cr2TiC2FCl. We find that compared with the acoustic magnons, the optical magnons have stronger interaction with phonon modes. Moreover, relaxation time of optical magnons and acoustic magnons have quite different wavevector dependence. Our results about spin coupling to specific phonon polarizations can shed light on the understanding of magnon damping and energy dissipation in two-dimensional antiferromagnetic materials.

Isolation and Characterization of New Anti-Inflammatory and Antioxidant Components from Deep Marine-Derived Fungus Myrothecium SP. Bzo-l062.

In the present study, four new compounds including a pair of 2-benzoyl tetrahydrofuran enantiomers, namely, (-)-1S-myrothecol (1a) and (+)-1R-myrothecol (1b), a methoxy-myrothecol racemate (2), and an azaphilone derivative, myrothin (3), were isolated along with four known compounds (4-7) from cultures of the deep-sea fungus Myrothecium sp. BZO-L062. Enantiomeric compounds 1a and 1b were separated through normal-phase chiral high-performance liquid chromatography. The absolute configurations of 1a, 1b, and 3 were assigned by ECD spectra. Among them, the new compound 1a and its enantiomer 1b exhibited anti-inflammatory activity, inhibited nitric oxide formation in lipopolysaccharide-treated RAW264.7 cells, and exhibited antioxidant activity in the 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and oxygen radical absorbance capacity assays.

Methyl-coenzyme M reductase-dependent endogenous methane enhances plant tolerance against abiotic stress and alters ABA sensitivity in Arabidopsis thaliana.

KEY MESSAGE: Our study firstly elaborated the underlying mechanism of endogenous CH4-induced abiotic tolerance, along with an alteration of ABA sensitivity by mimicking the endogenous CH4 production in MtMCR transgenic Arabidopsis. Endogenous methane (CH4) production and/or emission have been ubiquitously observed in stressed plants. However, their physiological roles remain unclear. Here, the methyl-coenzyme M reductase gene from Methanobacterium thermoautotrophicum (MtMCR), encoding the enzyme of methanogenesis, was expressed in Arabidopsis thaliana, to mimic the production of endogenous CH4. In response to salinity and osmotic stress, MtMCR expression was up-regulated in transgenic plants, resulting in significant increase of endogenous CH4 levels. Similar results were observed in abscisic acid (ABA) treatment. The functions of endogenous CH4 were characterized by the changes in plant phenotypes related to stress and ABA sensitivity during the germination and post-germination periods. When challenged with osmotic stress, a reduction in water loss and stomatal closure, were observed. Redox homeostasis was reestablished during osmotic and salinity stress, and ion imbalance was also restored in salinity conditions. The expression of several stress/ABA-responsive genes was up-regulated, and ABA sensitivity, in particularly, was significantly altered in the MtMCR transgenic plants. Together, our genetic study for the first time elaborated the possible mechanism of endogenous CH4-enhanced salinity and osmotic tolerance, along with an alteration of ABA sensitivity. These findings thus provided novel cues for understanding the possible roles of endogenous CH4 in plants.

Methane Control of Adventitious Rooting Requires γ-Glutamyl Cysteine Synthetase-Mediated Glutathione Homeostasis.

Although the key role of methane (CH4) in the induction of cucumber adventitious rooting has been observed previously, the target molecules downstream of the CH4 action are yet to be fully elucidated. Here, we reported that exogenous glutathione (GSH) induced cucumber adventitious root formation; while l-buthionine-sulfoximine (BSO) treatment inhibited it. BSO is a known inhibitor of γ-glutamyl cysteine synthetase (γ-ECS), an enzyme involved in GSH biosynthesis. Further investigations showed that endogenous GSH content was rapidly increased by CH4 application, which was correlated with the increased CsGSH1 transcript and γ-ECS activity. Mimicking the responses of GSH, CH4 could upregulate cell cycle regulatory genes (CsCDC6, CsCDPK1, CsCDPK5 and CsDNAJ-1) and auxin-response genes (CsAux22D-like and CsAux22B-like). Meanwhile, adventitious rooting-related CsmiR160 and CsmiR167 were increased or decreased, respectively, and contrasting tendencies were observed in the changes of their target genes, that included CsARF17 and CsARF8. The responses above were impaired by the removal of endogenous GSH with BSO, indicating that CH4-triggered adventitious rooting was GSH-dependent. Genetic evidence revealed that in the presence of CH4, Arabidopsis mutants cad2 (a γ-ECS-defective mutant) exhibited, not only the decreased GSH content in vivo, but also the defects in adventitious root formation, both of which were rescued by GSH administration other than CH4. Together, it can be concluded that γ-ECS-dependent GSH homeostasis might be required for CH4-induced adventitious root formation.