Advances in Molecular Plant Sciences.

In recent years, as biotechnological advancements have continued to unfold, our understanding of plant molecular biology has undergone a remarkable transformation [...].

Persulfidation-based Modification of Cysteine Desulfhydrase and the NADPH Oxidase RBOHD Controls Guard Cell Abscisic Acid Signaling.

Hydrogen sulfide (H2S) is a gaseous signaling molecule that regulates diverse cellular signaling pathways through persulfidation, which involves the post-translational modification of specific Cys residues to form persulfides. However, the mechanisms that underlie this important redox-based modification remain poorly understood in higher plants. We have, therefore, analyzed how protein persulfidation acts as a specific and reversible signaling mechanism during the abscisic acid (ABA) response in Arabidopsis (Arabidopsis thaliana). Here we show that ABA stimulates the persulfidation of l-CYSTEINE DESULFHYDRASE1, an important endogenous H2S enzyme, at Cys44 and Cys205 in a redox-dependent manner. Moreover, sustainable H2S accumulation drives persulfidation of the NADPH oxidase RESPIRATORY BURST OXIDASE HOMOLOG PROTEIN D (RBOHD) at Cys825 and Cys890, enhancing its ability to produce reactive oxygen species. Physiologically, s-persulfidation-induced RBOHD activity is relevant to ABA-induced stomatal closure. Together, these processes form a negative feedback loop that fine-tunes guard cell redox homeostasis and ABA signaling. These findings not only expand our current knowledge of H2S function in the context of guard cell ABA signaling, but also demonstrate the presence of a rapid signal integration mechanism involving specific and reversible redox-based post-translational modifications that occur in response to changing environmental conditions.

Hydrogen Sulfide-Linked Persulfidation Maintains Protein Stability of ABSCISIC ACID-INSENSITIVE 4 and Delays Seed Germination.

Hydrogen sulfide (H2S) is an endogenous gaseous molecule that plays an important role in the plant life cycle. The multiple transcription factor ABSCISIC ACID INSENSITIVE 4 (ABI4) was precisely regulated to participate in the abscisic acid (ABA) mediated signaling cascade. However, the molecular mechanisms of how H2S regulates ABI4 protein level to control seed germination and seedling growth have remained elusive. In this study, we demonstrated that ABI4 controls the expression of L-CYSTEINE DESULFHYDRASE1 (DES1), a critical endogenous H2S-producing enzyme, and both ABI4 and DES1-produced H2S have inhibitory effects on seed germination. Furthermore, the ABI4 level decreased during seed germination while H2S triggered the enhancement of the persulfidation level of ABI4 and alleviated its degradation rate, which in turn inhibited seed germination and seedling establishment. Conversely, the mutation of ABI4 at Cys250 decreased ABI4 protein stability and facilitated seed germination. Moreover, ABI4 degradation is also regulated via the 26S proteasome pathway. Taken together, these findings suggest a molecular link between DES1 and ABI4 through the post-translational modifications of persulfidation during early seedling development.

Hydrogen sulfide, a signaling molecule in plant stress responses.

Gaseous molecules, such as hydrogen sulfide (H2 S) and nitric oxide (NO), are crucial players in cellular and (patho)physiological processes in biological systems. The biological functions of these gaseous molecules, which were first discovered and identified as gasotransmitters in animals, have received unprecedented attention from plant scientists in recent decades. Researchers have arrived at the consensus that H2 S is synthesized endogenously and serves as a signaling molecule throughout the plant life cycle. However, the mechanisms of H2 S action in redox biology is still largely unexplored. This review highlights what we currently know about the characteristics and biosynthesis of H2 S in plants. Additionally, we summarize the role of H2 S in plant resistance to abiotic stress. Moreover, we propose and discuss possible redox-dependent mechanisms by which H2 S regulates plant physiology.

Abscisic acid-triggered guard cell l-cysteine desulfhydrase function and in situ hydrogen sulfide production contributes to heme oxygenase-modulated stomatal closure.

Recent studies have demonstrated that hydrogen sulfide (H2 S) produced through the activity of l-cysteine desulfhydrase (DES1) is an important gaseous signaling molecule in plants that could participate in abscisic acid (ABA)-induced stomatal closure. However, the coupling of the DES1/H2 S signaling pathways to guard cell movement has not been thoroughly elucidated. The results presented here provide genetic evidence for a physiologically relevant signaling pathway that governs guard cell in situ DES1/H2 S function in stomatal closure. We discovered that ABA-activated DES1 produces H2 S in guard cells. The impaired guard cell ABA phenotype of the des1 mutant can be fully complemented when DES1/H2 S function has been specifically rescued in guard cells and epidermal cells, but not mesophyll cells. This research further characterized DES1/H2 S function in the regulation of LONG HYPOCOTYL1 (HY1, a member of the heme oxygenase family) signaling. ABA-induced DES1 expression and H2 S production are hyper-activated in the hy1 mutant, both of which can be fully abolished by the addition of H2 S scavenger. Impaired guard cell ABA phenotype of des1/hy1 can be restored by H2 S donors. Taken together, this research indicated that guard cell in situ DES1 function is involved in ABA-induced stomatal closure, which also acts as a pivotal hub in regulating HY1 signaling.

Metal-organic framework photonic crystals with bidisperse particles-based brilliant structural colors and high optical transparency for elaborate anti-counterfeiting.

Photonic crystals (PCs) have attracted great interest and wide applications in displays, printing, anti-counterfeiting, etc. However, two main challenges significantly hinder their applications: 1) the tradeoff between high optical transparency across the whole visible range and brilliant colors requiring a large refractive index contrast (Δn), and 2) the way of regulating structural colors by altering tens of different sizes. To address these issues, a new type of metal-organic framework (MOF)-based transparent photonic crystal (TPC) has been fabricated through self-assembling MOF particles into three-dimensional ordered structures which were then infiltrated by polydimethylsiloxane (PDMS). Compared to conventional PCs, these TPCs exhibit 1) both brilliant forward iridescent structural colors and high transmittance (>75 %) across the whole visible spectra range, and 2) conveniently adjustable colors based on bidisperse particles. The unique color-generating mechanism of the light diffraction by each plane lattice and the small Δn between MOF particles and PDMS are the keys to TPCs' characteristics. Moreover, the prepared invisible anti-counterfeit labels can reversibly hide-reveal patterns with elaborate and exchangeable color contrast in a non-destructive way, showing potential applications in anti-counterfeiting, information encryption, and optical devices.

Crossing the domain: Unintended consequences of safety and service climates.

Domain-specific roles of service climate and safety climate are well-established, but little is known about their cross-domain roles. In this study, we examined the cross-domain main roles of service climate (on safety performance) and safety climate (on service performance) and their joint roles in predicting service and safety performance. Drawing on the exploration-exploitation framework, we further introduced team exploration and team exploitation as explanatory mechanisms for the cross-domain relationships. We conducted two multiwave, multisource field studies using nursing teams in hospitals. Results from Study 1 showed that service climate had a positive relationship with service performance but a nonsignificant relationship with safety performance. Safety climate, though, had a positive relationship with safety performance but a negative relationship with service performance. Study 2 found support for all main relationships and also revealed that safety climate moderated the indirect relationships that service climate had with safety and service performance through team exploration. Moreover, service climate moderated the indirect relationships that safety climate had with service and safety performance through team exploitation. We extend the climate literature by uncovering the missing cross-domain relationships between service and safety climates. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Prediction and Control of Thermal Transport at Defective State Gr/h-BN Heterojunction Interfaces.

The control of interfacial thermal conductivity is the key to two-dimensional heterojunction in semiconductor devices. In this paper, by using non-equilibrium molecular dynamics (NEMD) simulations, we analyze the regulation of interfacial thermal energy transport in graphene (Gr)/hexagonal boron nitride (h-BN) heterojunctions and reveal the variation mechanism of interfacial thermal energy transport. The calculated results show that 2.16% atomic doping can effectively improve interfacial heat transport by more than 15.6%, which is attributed to the enhanced phonon coupling in the mid-frequency region (15-25 THz). The single vacancy in both N and B atoms can significantly reduce the interfacial thermal conductivity (ITC), and the ITC decreases linearly with the increase in vacancy defect concentration, mainly due to the single vacancy defects leading to an increased phonon participation rate (PPR) below 0.4 in the low-frequency region (0-13 THz), which shows the phonon the localization feature, which hinders the interfacial heat transport. Finally, a BP neural network algorithm is constructed using machine learning to achieve fast prediction of the ITC of Gr/h-BN two-dimensional heterogeneous structures, and the results show that the prediction error of the model is less than 2%, and the method will provide guidance and reference for the design and optimization of the ITC of more complex defect-state heterogeneous structures.

Hollow mesoporous cubic silica self-assembling into photonic crystals with rhombohedral lattices and vivid structural colors for anti-counterfeiting.

Colloidal photonic crystals (PCs) feature face-centered cubic (FCC) lattices since spherical particles are usually used as building blocks; however, constructing structural colors originating from PCs with non-FCC lattices is still a big challenge due to the difficulty in preparing non-spherical particles with tunable morphologies, sizes, uniformity, and surface properties and assembling them into ordered structures. Here, uniform, positively charged, and hollow mesoporous cubic silica particles (hmc-SiO2) with tunable sizes and shell thicknesses prepared by a template approach are used to self-assemble into PCs with rhombohedral lattice. The reflection wavelengths and structural colors of the PCs can be controlled by altering the sizes or the shell thicknesses of the hmc-SiO2. Additionally, photoluminescent PCs have been fabricated by taking the advantage of the click chemistry between amino silane and isothiocyanate of a commercial dye. The PC pattern achieved by a hand-writing way with the solution of the photoluminescent hmc-SiO2 instantly and reversibly shows the structural color under visible light but a different photoluminescent color under UV illumination, which is useful for anticounterfeiting and information encryption. The non-FCC structured and photoluminescent PCs will upgrade the basic understanding of the structural colors and facilitate their applications in optical devices, anti-counterfeiting, and so forth.

Notoginsenoside R1 alleviates spinal cord injury by inhibiting oxidative stress, neuronal apoptosis, and inflammation via activating the nuclear factor erythroid 2 related factor 2/heme oxygenase-1 signaling pathway.

The secondary injury plays a vital role in the development of spinal cord injury (SCI), which is characterized by the occurrence of oxidative stress, neuronal apoptosis, and inflammatory response. Notoginsenoside R1 (NGR1) has been involved in the modulation of antioxidative stress and anti-inflammatory response. However, its roles in SCI-induced injury are still unknown. We explored the therapeutic effect of NGR1 and its underlying mechanism after SCI by using behavioral, biochemical, and immunohistochemical techniques. The administration of NGR1 after SCI enhanced the neurological function, and mitigated tissue damage and motor neuron loss than those in SCI + vehicle group. Meanwhile, significantly increased expression of Nrf2 protein and HO-1 protein was found in the SCI + NGR1 group compared with those in the SCI + vehicle group. In addition, the inhibitory effects of oxidative stress, apoptotic neuron ratio, and neuronal inflammation in the SCI + NGR1 group can be partially reversed when the Nrf2/HO-1 signaling pathway was inhibited by ML385. Our results indicate that the administration of NGR1 can attenuate oxidative stress, neuronal apoptosis, and inflammation by activating the Nrf2/HO-1 signaling pathway after SCI, thereby improving neurological function.

Treatment of fresh leachate by microaeration pretreatment combined with IC-AO2 process: Performance and mechanistic insight.

Fresh leachate is commonly featured with high concentrations of degradable organic matters, which can impede the performance of traditional biological treatment, especially the anaerobic reactor. Aiming at improving the biological treatment process of fresh leachate, this study creatively proposed a microaerobic-IC-AO2 (MAICAO2) process and compared it with traditional biological process, then optimized the operating conditions. Meanwhile, this work investigated the transformation rules and molecular compositions of dissolved organic matters (DOM) during MAICAO2 process, particularly the hazardous DOM (antibiotics). The innovative MAICAO2 process can effectively remove 99% chemical oxygen demand (COD), 91% total nitrogen (TN) and 91% ammonia (NH4+-N) during the operation time, and the removal efficiencies of COD, TN and NH4+-N in MAICAO2 process increased approximately 2%, 14% and 13% compared to ICAOAO process. Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) confirmed that microaeration could ensure over 53% small molecular organic acids degrade before the subsequent anaerobic reaction so the system could resist the high concentration organic matters stress and improve the denitrification efficiency. Further analysis showed that different categories of antibiotics (including 6 sulfonamides, 4 tetracyclines, 2 macrolides, 4 quinolones and 2 chloramphenicols) could be effectively removed by MAICAO2 process with the total removal efficiency of 50%. This work proposed a new scenario for fresh leachate treatment by proposing the importance of the microaeration pretreatment during the biological treatment process.

The coordination of guard-cell autonomous ABA synthesis and DES1 function in situ regulates plant water deficit responses.

INTRODUCTION: Drought stress triggers the synthesis and accumulation of the phytohormone abscisic acid (ABA), which regulates stomatal aperture and hence reducing plant water loss. Hydrogen sulfide (H2S), which is produced by the enzyme L-cysteine desulfhydrase 1 (DES1) that catalyzes the desulfuration of L-cysteine in Arabidopsis, also plays a critical role in the regulation of drought-induced stomatal closure. However, little is known about the regulation of DES1 or the crosstalk between H2S and ABA signaling in response to dehydration. OBJECTIVES: To demonstrate the potential crosstalk between DES1-dependent H2S and ABA signaling in response to dehydration and its regulation mechanism. METHODS: Firstly, by introducing guard cell-specific MYB60 promoter, to produce complementary lines of DES1 or ABA3 into guard cell of des1 or aba3 mutant. And the related genes expression and water loss under ABA, NaHS, or dehydration treatment in these mutant or transgenics lines were determinate. RESULTS: We found that dehydration-induced expression of DES1 is abolished in the abscisic acid deficient 3 (aba3) mutants that are deficient in ABA synthesis. Both the complementation of ABA3 expression in guard cells of the aba3 mutants and ABA treatment rescue the dehydration-induced expression of DES1, as well as the wilting phenotype observed in these mutants. Moreover, the drought-induced expression of ABA synthesis genes was suppressed in des1 mutants. While the addition of ABA or the expression of either ABA3 or DES1 in the guard cells of the aba3/des1 double mutant did not alter the wilting phenotype of these mutants, the wild type phenotype was fully restored by the expression of both ABA3 and DES1, or by the application of NaHS. CONCLUSION: These results demonstrate that the coordinated synthesis of ABA and DES1 expression is required for drought-induced stomatal closure in Arabidopsis.

Hydrogen sulfide-linked persulfidation of ABI4 controls ABA responses through the transactivation of MAPKKK18 in Arabidopsis.

Hydrogen sulfide (H2S) is a signaling molecule that regulates plant hormone and stress responses. The phytohormone abscisic acid (ABA) plays an important role in plant adaptation to unfavorable environmental conditions and induces the persulfidation of L-CYSTEINE DESULFHYDRASE1 (DES1) and the production of H2S in guard cells. However, it remains largely unclear how H2S and protein persulfidation participate in the relay of ABA signals. In this study, we discovered that ABSCISIC ACID INSENSITIVE 4 (ABI4) acts downstream of DES1 in the control of ABA responses in Arabidopsis. ABI4 undergoes persulfidation at Cys250 that is triggered in a time-dependent manner by ABA, and loss of DES1 function impairs this process. Cys250 and its persulfidation are essential for ABI4 function in the regulation of plant responses to ABA and the H2S donor NaHS during germination, seedling establishment, and stomatal closure, which are abolished in the ABI4Cys250Ala mutated variant. Introduction of the ABI4Cys250Ala variant into the abi4 des1 mutant did not rescue its hyposensitivity to ABA. Cys250 is critical for the binding of ABI4 to its cognate motif in the promoter of Mitogen-Activated Protein Kinase Kinase Kinase 18 (MAPKKK18), which propagates the MAPK signaling cascade induced by ABA. Furthermore, the DES1-mediated persulfidation of ABI4 enhances the transactivation activity of ABI4 toward MAPKKK18, and ABI4 can bind the DES1 promoter, forming a regulatory loop. Taken together, these findings advance our understanding of a post-translational regulatory mechanism and suggest that ABI4 functions as an integrator of ABA and MAPK signals through a process in which DES1-produced H2S persulfidates ABI4 at Cys250.

Redox-based protein persulfidation in guard cell ABA signaling.

Hydrogen sulfide (H2S) is a versatile signaling molecule that regulates multiple physiological processes in plants, including growth and development, immunity, and stress response as well. Signaling triggered by H2S is proposed to occur via persulfidation, an oxidative post-translational modification (PTM) of cysteine residues (-SH) to persulfides (-SSH). Notwithstanding the growing body of information for the plant persulfidation proteome, the gap between the molecular mechanism of H2S and physiological functions of protein persulfidation remains large. In this mini-review, we discussed the specific regulatory mechanism of persulfidation on guard cell abscisic acid (ABA) signaling and the possible link of persulfidation, sulfenylation, and S-nitrosylation within the framework of redox-based regulation.

Current approaches for detection of hydrogen sulfide and persulfidation in biological systems.

The past decades have witnessed hydrogen sulfide (H2S) serving as gaseous signaling molecule participating in diverse cellular and physiological processes in biological systems. Recently, a considerable number of studies highlight the signaling role of this redox-regulating molecule occurs via persulfidation, which is a post-translation modification of protein cysteine residues by covalent addition of thiol group form persulfide. However, our current understanding on detection of H2S and persulfidation in biological systems still lags behind. This review aims to summarize current approaches for measuring H2S and persulfidated levels in biological systems. Meanwhile, potential interference may exist in plant research has been proposed and discussed.

How does a servant leader fuel the service fire? A multilevel model of servant leadership, individual self identity, group competition climate, and customer service performance.

Building on a social identity framework, our cross-level process model explains how a manager's servant leadership affects frontline employees' service performance, measured as service quality, customer-focused citizenship behavior, and customer-oriented prosocial behavior. Among a sample of 238 hairstylists in 30 salons and 470 of their customers, we found that hair stylists' self-identity embedded in the group, namely, self-efficacy and group identification, partially mediated the positive effect of salon managers' servant leadership on stylists' service performance as rated by the customers, after taking into account the positive influence of transformational leadership. Moreover, group competition climate strengthened the positive relationship between self-efficacy and service performance.