Abstract
Nitric oxide (NO) is a key signaling molecule affecting the response of plants to salt stress; however, the underlying molecular mechanism is poorly understood. In this study, we conducted a ...phenotype analysis and found that the small GTPase RABG3E (RAB7) promotes salt tolerance in
Arabidopsis thaliana
. NO promotes the
S
‐nitrosylation of RAB7 at Cys‐171, which in turn helps maintain the ion balance in salt‐stressed plants. Furthermore, the
S
‐nitrosylation of RAB7 at Cys‐171 enhances the enzyme's GTPase activity, thereby promoting vesicle trafficking and increasing its interaction with phosphatidylinositol phosphates—especially phosphatidylinositol‐4‐phosphate (PI4P). Exogenously applied PI4P increases vesicle trafficking and promotes salt tolerance depending on the
S
‐nitrosylation of RAB7 at Cys‐171. These findings illustrate a unique mechanism in salt tolerance, by which NO regulates vesicle trafficking and ion homeostasis through the
S
‐nitrosylation of RAB7 and its interaction with PI4P.
Summary statement
Nitric oxide‐mediated
S
‐nitrosylation of a RAB GTPase RABG3E modulates vesicle transport relying on its interaction with phosphatidylinositol‐4‐phosphate to enhance salt tolerance in
Arabidopsis thaliana
.
Brassinosteroid and gibberellin promote many similar developmental responses in plants; however, their relationship remains unclear. Here we show that BR and GA act interdependently through a direct ...interaction between the BR-activated BZR1 and GA-inactivated DELLA transcription regulators. GA promotion of cell elongation required BR signalling, whereas BR or active BZR1 suppressed the GA-deficient dwarf phenotype. DELLAs directly interacted with BZR1 and inhibited BZR1-DNA binding both in vitro and in vivo. Genome-wide analysis defined a BZR1-dependent GA-regulated transcriptome, which is enriched with light-regulated genes and genes involved in cell wall synthesis and photosynthesis/chloroplast function. GA promotion of hypocotyl elongation requires both BZR1 and the phytochrome-interacting factors (PIFs), as well as their common downstream targets encoding the PRE-family helix-loop-helix factors. The results demonstrate that GA releases DELLA-mediated inhibition of BZR1, and that the DELLA-BZR1-PIF4 interaction defines a core transcription module that mediates coordinated growth regulation by GA, BR and light signals.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Significant variation can be found in measurements for the longitudinal tensile strength of the same unidirectional (UD) composite. A splitting failure is one of the main reasons. It is shown in this ...paper that the shear stress component resulted from a longitudinal tension and a fiber misalignment can cause the matrix to fail before fiber break. The misalignment angle consists of an initial off‐axial angle and a further fiber rotation during the loading. Based on the micromechanics Bridging Model and the matrix true stress theory established by the author, splitting failure has been analyzed and predicted rigorously in this paper, only using the fiber and matrix properties together with the fiber misalignment angle. The fiber initial misalignment angle of a unidirectional plate can be obtained from testing statistics, or deducing from measured longitudinal compression strength. Our research indicates that the longitudinal tensile strength and the relevant failure mode can be significantly affected by the fiber initial misalignment.
An easily ignored failure mode and relative mechanical analysis of a composite under longitudinal tension are given. Such a failure is caused by matrix tension‐shear failure due to an unavoidable fiber misalignment. It has been found that the tension strengths are very sensitive to fiber initial misalignment angle.
In scientific journals published all over the world, the economic performance of firms with ISO 14001 certification is a highly controversial topic. This controversy is particularly evident in ...developing countries. With regard to this topic, we maintain a neutral position in this paper. Using the data of 63 firms from the Shenzhen and Shanghai Stock Exchanges in China during the period of 2003–2018, and employing the difference-in-difference method, we analyze the influence of ISO 14001 certification on firms’ financial performance. We also examine the moderating effect of firm size and age, considering the time factor. In addition, we test the influence of ISO 14001 certification on exports, using China’s provincial data from 2008 to 2018. The results indicate that ISO 14001 certification negatively affects the financial performance of firms; also, the negative effects decrease in line with the increase of certification time. Firm size and age are positively related to the relationship between ISO 14001 certification and a firm’s financial performance. At the same time, ISO 14001 certification can effectively improve a firm’s competitiveness in the international market. The study combines two opposing positions found in existing literature regarding the effectiveness of ISO 14001 certification. The results show that ISO 14001 certification will ultimately have a positive impact on China’s economy, but that influence should be correctly evaluated in terms of the effect on small and medium-sized enterprises. Some suggestions for firm managers and the government are then discussed.
Brassinosteroid (BR) regulates gene expression and plant development through a receptor kinase-mediated signal transduction pathway. Despite the identification of many components of this pathway, it ...remains unclear how the BR signal is transduced from the cell surface to the nucleus. Here we describe a complete BR signalling pathway by elucidating key missing steps. We show that phosphorylation of BSK1 (BR-signalling kinase 1) by the BR receptor kinase BRI1 (BR-insensitive 1) promotes BSK1 binding to the BSU1 (BRI1 suppressor 1) phosphatase, and BSU1 inactivates the GSK3-like kinase BIN2 (BR-insensitive 2) by dephosphorylating a conserved phospho-tyrosine residue (pTyr 200). Mutations that affect phosphorylation/dephosphorylation of BIN2 pTyr200 (bin2-1, bin2-Y200F and quadruple loss-of-function of BSU1-related phosphatases) support an essential role for BSU1-mediated BIN2 dephosphorylation in BR-dependent plant growth. These results demonstrate direct sequential BR activation of BRI1, BSK1 and BSU1, and inactivation of BIN2, leading to accumulation of unphosphorylated BZR (brassinazole resistant) transcription factors in the nucleus. This study establishes a fully connected BR signalling pathway and provides new insights into the mechanism of GSK3 regulation.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
•In this paper, a micromechanics model of particle reinforced polymer composite (PRPC) under tension are given.•Interfacial debonding is considered to discounts the strength of composite by ...intensifying the stress concentration in matrix. Two stress concentration factors (SCFs) are respectively defined for PRPC before and after interface debonding, and used in failure criteria.•The occurrence of interface debonding and final failure of PRPC are predicted only based on constituted material’s mechanical properties.•Influencing factors of strength are analyzed. Interface strength and particle size determine the initiation of interface crack and the PRPC's overall strength.
Strength prediction of a particle reinforced polymer composite (PRPC) is still challenging. Although a PRPC is overall isotropic, it is more difficult to predict its tensile strength accurately than a continuous fiber reinforced composite (CFRC). One reason for this difficulty is that the calculation of stress fields of the constituents in a PRPC are complicated. The other reason is that the strength of a PRPC is significantly affected by interfacial strength, which is hard to be measured directly. In our research, the discount of the composite strength after debonding is attributed to the intensifying stress concentration. Two stress concentration factors (SCFs) are derived respectively to characterize the stress fluctuations in the matrix caused by the embedded particle before and after debonding. Based on the micromechanics Bridging Model and the matrix true stress theory, these two SCFs can be applied to evaluate the interface strength and the ultimate tensile strength of the composite from the properties of its component materials. Illustrations are presented to verify the efficiency of our theory and analyze the main influencing factors on the strength of the PRPC, including mechanical properties of component materials, particle size and volume fraction.
One of the remaining challenges for advancing the theoretical mechanics of composite materials is to describe the relationship between interfacial debonding and the mechanical properties of ...composites. The fiber/matrix interfacial debonding of model composites caused by combined loading has been observed by in-situ X-ray radiography and post-mortem X-ray computed tomography (CT) in this paper. Off-axis tension (fiber axis lying at 30°, 45°, 60° or 90° with respect to the loading direction) tests have been performed on carbon fiber reinforced polymer (CFRP) cruciform specimens using an in-situ loading rig. The morphological characteristics of the cracks at the interface and in the matrix are recorded. Based on our observations, the difference between interfacial debonding caused by normal tension and tangential shear stresses and their cooperative actions in composites under combined loading have been studied. This research can give insights into interfacial debonding in composites and help to build an accurate micro-mechanical model.
The wall-associated kinase (WAK) multigene family plays critical roles in various cellular processes and stress responses in plants, however, whether WAKs are involved in salt tolerance is obscure. ...Herein, we report the functional characterization of a rice WAK,
WAK112
, whose expression is suppressed by salt. Overexpression of
OsWAK112
in rice and heterologous expression of
OsWAK112
in
Arabidopsis
significantly decreased plant survival under conditions of salt stress, while knocking down the
OsWAK112
in rice increased plant survival under salt stress. OsWAK112 is universally expressed in plant and associated with cell wall. Meanwhile,
in vitro
kinase assays and salt tolerance analyses showed that OsWAK112 possesses kinase activity and that it plays a negative role in the response of plants to salt stress. In addition, OsWAK112 interacts with S-adenosyl-L-methionine synthetase (SAMS) 1/2/3, which catalyzes SAM synthesis from ATP and L-methionine, and promotes OsSAMS1 degradation under salt stress. Furthermore, in
OsWAK112
-overexpressing plants, there is a decreased SAMS content and a decreased ethylene content under salt stress. These results indicate that OsWAK112 negatively regulates plant salt responses by inhibiting ethylene production, possibly
via
direct binding with OsSAMS1/2/3.
A discrete tetrahedral indium cage, {In12(μ3-OH)4(HCO2)24(tcma)4} (In12-GL), was synthesized solvothermally by the reaction of indium nitrate with the tripodal tricarboxylic acid ligand ...N,N,N-tris{(2′-carboxy1,1′-biphenyl-4-yl)methyl}methylammonium chloride (H3tcma+Cl). This cage consists of four trimeric units In3(μ3-OH)(μ2-CO2)3(μ2-HCO2)3 and four tcma2– ligands, which all perform as 3-connection nodes to bridge each other, resulting in a tetrahedral cage structure. The trimeric unit In3(μ3-OH)(μ2-CO2)3(μ2-HCO2)3 is observed for the first time in the family of In-based metal–organic structures and can be considered as an evolution of a 6-connected In3(μ3-O)(μ2-CO2)6 unit. Each In3+ is terminally coordinated by a μ1-HCO2 group. This cage contains potential Lewis acidic/basic active sites endowed by In3+ ions as Lewis acidic sites and the uncoordinated oxygen atoms of μ1-HCO2 moieties as Lewis basic sites and was explored as an effective heterogeneous catalyst in the cycloaddition of CO2 with epoxides and the Strecker reaction for amino nitriles. These catalytic reactions were deduced to happen on the surface of the In12-GL cage.
Maternal ageing is one of the major causes of reduced ovarian reserve and low oocyte quality in elderly women. Decreased oocyte quality is the main cause of age‐related infertility. Mitochondria are ...multifunctional energy stations that determine the oocyte quality. The mitochondria in aged oocytes display functional impairments with mtDNA damage, which leads to reduced competence and developmental potential of oocytes. To improve oocyte quality, mitochondrial supplementation is carried out as a potential therapeutic approach. However, the selection of suitable cells as the source of mitochondria remains controversial. We cultivated endometrial mesenchymal stem cells (EnMSCs) from aged mice and extracted mitochondria from EnMSCs. To improve the quality of oocytes, GV oocytes were supplemented with mitochondria via microinjection. And MII oocytes from aged mice were fertilized by intracytoplasmic sperm injection (ICSI), combining EnMSCs' mitochondrial microinjection. In this study, we found that the mitochondria derived from EnMSCs could significantly improve the quality of aged oocytes. Supplementation with EnMSC mitochondria significantly increased the blastocyst ratio of MII oocytes from aged mice after ICSI. We also found that the birth rate of mitochondria‐injected ageing oocytes was significantly increased after embryo transplantation. Our study demonstrates that supplementation with EnMSC‐derived mitochondria can improve the quality of oocytes and promote embryo development in ageing mice, which might provide a prospective strategy for clinical treatment.
In this study, we chose endometrial mesenchymal stem cells (EnMSCs) as the sources of mitochondria. We isolated the EnMSCs from 10‐month‐old mice and then extracted the mitochondria of EnMSCs. Then, the GV oocytes and MII oocytes from aged mice were injected with mitochondria. We found that mitochondria derived from EnMSCs could significantly improve the quality of oocytes, promote the embryonic development and improve the birth rates of aged mice.
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