Two 9,10‐distyrylanthracene‐based luminophores exhibiting aggregation‐induced emission and stimuli‐responsive properties were synthesized. Seven‐ or five‐color luminescence switching based on a ...single organic molecule was achieved for the first time. These phase transitions can be induced by physical stimuli such as grinding by mortar and pestle, heating, and exposure to the vapors of organic solvents. Moreover, a strategy for the design of new mechanoresponsive materials with π‐conjugated luminophores is proposed.
Seven‐color luminophore: Piezochromism based on aggregation‐induced emission with distinct seven‐color luminescence switching built on a single organic molecule was achieved for the first time. The fluorescence switching process (see figure) can be smoothly triggered by disrupting the ordered molecular packing (mechanical grinding) and repacking (heating or solvent annealing).
•A rationmetric emission pH probe CzBI is facilely synthesized.•CzBI exhibits a remarkable emission ratio (F605nm/F523nm) enhancement with decreasing pH from 7.00 to 0.50.•The pKa is 2.44 and the ...linear pH response range lies in the extremely acidic pH range of 1.50–3.60.•CzBI can monitor pH fluctuations in HeLa cells and extremely acidic pH changes (pH 1.0–4.0) in E. coli cells with ratiometric response.
A ratiometric emission fluorescent probe 1,1-dimethyl-2-(2-(N-ethyl-carbazol-3-yl)-vinyl)-1H-benzoeindole (CzBI) is facilely synthesized via the ethylene bridging of carbazoaldehyde and benzoindole. The probe exhibits a remarkable emission ratio (F605 nm/F523 nm) enhancement with a pKa value of 2.44, and the linear response over the extremely acidic pH range of 1.50–3.60. CzBI also displays a large Stokes shift of 100nm under extremely acidic conditions, high sensitivity and excellent reversibility, which are favorable for intracellular acidic pH imaging. In addition, the probe has excellent cell membrane permeability and is applied successfully to visualize intracellular pH fluctuations in live cells and, further monitor extremely acidic pH changes in E. coli cells without influence of autofluorescence and native cellular species in biological systems.
The causal relationship between conformational folding and disulfide bonding in protein oxidative folding remains incompletely defined. Here we show a stage-dependent interplay between the two events ...in oxidative folding of C-reactive protein (CRP) in live cells. CRP is composed of five identical subunits, which first fold spontaneously to a near-native core with a correctly positioned C-terminal helix. This process drives the formation of the intra-subunit disulfide bond between Cys36 and Cys97. The second stage of subunit folding, however, is a non-spontaneous process with extensive restructuring driven instead by the intra-subunit disulfide bond and guided by calcium binding-mediated anchoring. With the folded subunits, pentamer assembly ensues. Our results argue that folding spontaneity is the major determinant that dictates which event acts as the driver. The stepwise folding pathway of CRP further suggests that one major route might be selected out of the many in theory for efficient folding in the cellular environment.
Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are an effective treatment for common EGFR mutations in non-small-cell lung cancer (NSCLC). Rarer EGFR mutations such as ...kinase domain duplications (KDDs) have been identified, but the optimal therapy following treatment resistance remains unknown. We report two patients who were diagnosed with NSCLC including KDD. For case 1, afatinib (40 mg once daily) was at first effective but then became ineffective. Consequently, osimertinib therapy (80 mg once daily) was administered. As of 26 May 2021, the osimertinib therapy achieved a stable disease state according to the chest computed tomography scan. As for case 2, the patient received second-line chemotherapy and anlotinib (12 mg once daily) for 6 months and died in May 2020. Here, we describe osimertinib as an effective therapy for EGFR-KDD positive lung adenocarcinoma and thereby provide a new alternative for further treatment following resistance to first- and second-generation EGFR-TKIs.
Due to the high compressive strength and excellent tensile properties of UHPC, reinforced UHPC with a thickness of 45 mm–60mm and a concrete cover of 15 mm–19mm has been used in the steel-UHPC ...lightweight composite deck. However, the researches about the bond behaviors of steel bar in UHPC with the concrete cover less than 20 mm were still limited. This paper aimed to study the bond behaviors of steel bars in UHPC with a thinner concrete cover (≤20 mm) and develop the calculation method for the lower bound of bond strength. A program of pullout test was conducted using the tensile test setup mimicking the tensile stress condition of structural members. The effects of concrete cover (10 mm, 15 mm and 20 mm), steel fiber volume fraction (0.5%, 1% and 2%), steel bar diameter (10 mm, 12 mm, 14 mm and 16 mm), embedment length of steel bar (4db, 6db, 8db, 10db) on the bond behaviors of steel bar in UHPC were investigated through 11 groups of pullout test specimens. The test results showed that most specimens failed in concrete cover splitting and the bond strength was influenced to different degrees by the test variates. The bond strength for steel bar in UHPC with a steel fiber volume fraction of 2% varied from 12.29 MPa to 15.88 MPa, and an embedment length of 8db with a concrete cover of 15 mm could ensure the steel bar with a diameter less than 16 mm reached its nominal yield stress of 400 MPa before the bond failure. On the basis of pullout test results in this study and the published test data, an empirical equation was proposed to predicted the lower bound of bond strength for steel bar in UHPC.
•The bonding behaviors of steel bar in UHPC with thin concrete cover (≤20 mm) were investigated.•The calculation method for the lower bound of bond strength for steel bar in UHPC was developed.•An assumed maximum bond strength was proposed to predict the required embedment length of steel bar in UHPC.
Homologous recombination (HR) and nonhomologous end joining (NHEJ) are considered the two main double-strand break (DSB) repair approaches in eukaryotes. Inhibiting the activities of the key ...component in NHEJ commonly enhances the efficiency of targeted gene knockouts or affects growth and development in higher eukaryotes. However, little is known about the roles of the NHEJ pathway in foliar pathogens. Here we identified a gene designated StKU80, which encodes a putative DNA end-binding protein homologous to yeast Ku80, in the foliar pathogen Exserohilum turcicum. Conserved domain analysis showed that the typical domains VWA, Ku78 and Ku-PK-bind are usually present in Ku70/80 proteins in eukaryotes and are also present in StKu80. Phylogenetic analysis indicated that StKu80 is most closely related to Ku80 (XP_001802136.1) from Parastagonospora nodorum, followed by Ku80 (AGF90044.1) from Monascus ruber. Furthermore, the gene knockout mutants ΔStKU80-1 and ΔStKU80-2 were obtained. These mutants displayed longer septas, thinner cell walls, smaller amounts of substances on cell wall surfaces, and more mitochondria per cell than the wild-type (WT) strain but similar HT-toxin activity. The mutants did not produce conidia and mature appressoria. On the other hand, the mutants were highly sensitive to H2O2, but not to ultraviolet radiation. In summary, the StKU80 plays devious roles in regulating the development of E. turcicum.
The mitogen-activated protein kinase （MAPK）, a key signal transduction component in the MAPK cascade pathway, regulates a variety of physiological activities in eukaryotes. However, little is known ...of the role MAPK plays in phytopathogenic fungi. In this research, we cloned the MAPK gene STK1 from the northern corn leaf blight pathogen Setosphaeria turcica and found that the gene shared high homology with the high osmolality glycerol （HOG） MAPK gene HOG1 of Saccharomy- ces cerevisiae. In addition, gene knockout technology was employed to investigate the function of STKI. Gene knockout mutants （KOs） were found to have altered hyphae morphology and no conidiogenesis, though they did show similar radial growth rate compared to the wild-type strain （WT）. Furthermore, microscope observations indicated that STK1 KOs did not form normal appressoria at 48 h post-inoculation on a hydrophobic surface. STK1 KOs had reduced virulence, a significantly altered Helminthosporium turcicum （HT）-toxin composition, and diminished pathogenicity on the leaves of susceptible inbred corn OH43. Mycelium morphology appeared to be significantly swollen and the radial growth rates of STK1 KOs declined in comparison with WT under high osmotic stress. These results suggested that STK1 affects the hyphae development, conidiogenesis, and pathogenicity of S. turcica by regulating appressorium development and HT-toxin biosynthesis. Moreover, the gene appears to be involved in the hypertonic stress response in S. turcica.
Abstract Cognitive impairment is a common adverse effect of electroconvulsive therapy (ECT) during treatment for severe depression. Dexmedetomidine (DEX), a sedative-anesthetic drug, is used to treat ...post-ECT agitation. However, it is not known if DEX can protect against ECT-induced cognitive impairments. To address this, we used chronic unpredictable mild stress (CUMS) to establish a model of depression for ECT treatment. Our Morris water maze and sucrose preference test results suggest that DEX alleviates ECT-induced learning and memory impairments without altering the antidepressant efficacy of ECT. To further investigate the underlying mechanisms of DEX, hippocampal expression of NR2B, p-ERK/ERK, p-CREB/CREB, and BDNF were quantified by western blotting. These results show that DEX suppresses over-activation of NR2B and enhances phosphorylation of ERK1/2 in the hippocampus of ECT-treated depressed rats. Furthermore, DEX had no significant effect on ECT-induced increases in p-CREB and BDNF. Overall, our findings suggest that DEX ameliorates ECT-induced learning and memory impairments in depressed rats via the NR2B-ERK signaling cascade. Moreover, CREB/BDNF does not appear to participate in the cognitive protective mechanisms of DEX during ECT treatment.
Abstract Increasing evidence indicates that dexmedetomidine (DEX), a selective α2-adrenergic receptor agonist, has a neuroprotective effect against cerebral injury. However, it remains unknown ...whether and how DEX functionally prevents the pathological form of synaptic plasticity caused by ischemia in the hippocampal CA1 neurons. To address this issue, we analyzed the role of DEX using a model of brain ischemia (oxygen and glucose deprivation, OGD) referred to as post-ischemic LTP (i-LTP). We found that DEX could reduce i-LTP by selectively activating α2 receptors. To clarify its detailed mechanisms, the presynaptic and postsynaptic roles of DEX were investigated. The activation of the α2 receptors of DEX decreased the frequency spontaneous mEPSCs, which exerted its presynaptic mechanisms. In addition, DEX also decreased the amplitude of mEPSCs and prevented the depolarization of postsynaptic membranes during OGD treatment, which exerted its postsynaptic mechanisms. More importantly, our results indicate that postsynaptic β receptors, not α1 receptors, participated in i-LTP. Therefore, these results demonstrated that decreasing β receptors activation by DEX-medicated pre- and post-synaptic α2 receptors activation is responsible for i-LTP. Because of the NMDARs required for i-LTP, we further examined the critical roles of postsynaptic β receptors downstream PKA regulation of NMDA receptor-mediated EPSCs (NMDA EPSC). We clarified that it is attributable to the direct effect of DEX on NMDA EPSC as mediated by PKA inactivation. These findings suggest that DEX can protect neurons from functional damage caused by a relatively mild degree of transient cerebral ischemia, and this effect is mediated by both presynaptic reduction of NE and glutamate release and postsynaptic suppression of NMDAR activation by β receptors and downstream PKA regulation.
In filamentous fungi, the pathogenic mitogen-activated protein kinase (PMK) pathway performs an important function in plant infection. STE12-like genes found in higher eukaryotes encode transcription ...factors and are regulated by the PMK pathway. However, the functions of STE12-like genes in foliar pathogens remain poorly understood. In this study, we cloned StSTE12 from Setosphaeria turcica and investigated its functions by RNA interference. Transformants ste12-3, ste12-2 and, ste12-1, in which the StSTE12 silencing efficiency increased in order, were confirmed by real time PCR. Compared with the wild-type (WT) strain, the transformants showed reduced growth rate, lighter colony color, and obviously decreased conidium production. More importantly, different to WT strain and ste12-3 with lower StSTE12silencing efficiency, ste12-1 and ste12-2 with higher StSTE12 silencing efficiency were nonpathogenic on intact leaves, but pathogenic on wounded leaves. However, the biological activity of HT-toxin from all transformants showed no difference on corn leaves. Furthermore, ste12-1 and ste12-2 did not penetrate artificial cellophane membrane and showed abnormal and delayed development appressoria. Although it could penetrate the cellophane membranes, ste12-3 formed appressoria after 48h of inoculation more than WT. Therefore, StSTE12 was involved in vegetative growth, conidiation, appressorial development, penetration as well as the pathogenicity, but it was not related to HT-toxin biosynthesis. More interestingly, all the results suggested that StSTE12 was crucial for pathogenicity due to involvement in regulating appressoria development and penetration.
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