Disrupted oxylipin biosynthesis mitigates pathogen infections and pest infestations in cotton (Gossypium hirsutum).

Cotton (Gossypium hirsutum) is the world's most important fiber crop, critical to global textile industries and agricultural economies. However, cotton yield and harvest quality are undermined by the challenges introduced from invading pathogens and pests. Plant-synthesized oxylipins, specifically 9-hydroxy fatty acids resulting from 9-lipoxygenase activity (9-LOX), enhance the growth and development of many microbes and pests. We hypothesized that targeted disruption of 9-LOX-encoding genes in cotton could bolster crop resilience against prominent agronomic threats. Fusarium oxysporum f. sp. vasinfectum (FOV), Aphis gossypii (cotton aphid), and Tobacco rattle virus induced the expression of 9-oxylipin biosynthesis genes, suggesting that the 9-LOX gene products were susceptibility factors to these stressors. Transiently disrupting the expression of the 9-LOX-encoding genes by virus-induced gene silencing significantly reduced target transcript accumulation, and this correlated with impaired progression of FOV infections and a significant decrease in the fecundity of cotton aphids. These findings emphasize that the cotton 9-LOX-derived oxylipins are leveraged by multiple pathogens and pests to enhance their virulence in cotton, and reducing the expression of 9-LOX-encoding genes can benefit cotton crop vitality.

Altered expression of SELF-PRUNING disrupts homeostasis and facilitates signal delivery to meristems.

Meristem maintenance, achieved through the highly conserved CLAVATA-WUSCHEL (CLV-WUS) regulatory circuit, is fundamental in balancing stem cell proliferation with cellular differentiation. Disruptions to meristem homeostasis can alter meristem size, leading to enlarged organs. Cotton (Gossypium spp.), the world's most important fiber crop, shows inherent variation in fruit size, presenting opportunities to explore the networks regulating meristem homeostasis and to impact fruit size and crop value. We identified and characterized the cotton orthologs of genes functioning in the CLV-WUS circuit. Using virus-based gene manipulation in cotton, we altered the expression of each gene to perturb meristem regulation and increase fruit size. Targeted alteration of individual components of the CLV-WUS circuit modestly fasciated flowers and fruits. Unexpectedly, controlled expression of meristem regulator SELF-PRUNING (SP) increased the impacts of altered CLV-WUS expression on flower and fruit fasciation. Meristem transcriptomics showed SP and genes of the CLV-WUS circuit are expressed independently from each other, suggesting these gene products are not acting in the same path. Virus-induced silencing of GhSP facilitated the delivery of other signals to the meristem to alter organ specification. SP has a role in cotton meristem homeostasis, and changes in GhSP expression increased access of virus-derived signals to the meristem.

Achieving High-Performance Perovskite Photovoltaic by Morphology Engineering of Low-Temperature Processed Zn-Doped TiO2 Electron Transport Layer.

Perovskite solar cells (PSCs) have become one of the most promising renewable energy converting devices. However, in order to reach a sufficiently high power conversion efficiency (PCE), the PSCs typically require a high-temperature sintering process to prepare mesostructured TiO2 as an efficient electron transport layer (ETL), which prohibits the PSCs from commercialization in the future. This work investigates a low-temperature synthesis of TiO2 nanocrystals and introduces a two-fluid spray coating process to produce a nanostructured ETL for the following deposition of perovskite layer. The temperature during the whole deposition process can be maintained under 150 °C. Compared to the typical planar TiO2 layer, the perovskite layer fabricated on a nanostructured TiO2 layer shows uniform compactness, preferred orientation, and high crystallinity, leading to reproducible and promising device performance. The detail mechanisms are revealed by the contact angle test, morphology characterization, grazing incident wide angle X-Ray scattering measurement, and space charge limited currents analysis. Finally, optimized device performance can be achieved through adequate Zn doping in the TiO2 layer, demonstrating an average PCE of 19.87% with champion PCE of 21.36%. The efficiency can maintain over 80% of its original value after 3000 h storage in ambient atmosphere. This study suggests a promising approach to offer high-efficiency PSCs using the low-temperature process.

G206D Mutation of Presenilin-1 Reduces Pen2 Interaction, Increases Aß42/Aß40 Ratio and Elevates ER Ca(2+) Accumulation.

Early-onset familial Alzheimer's disease (AD) is most commonly associated with the mutations in presenilin-1 (PS1). PS1 is the catalytic component of the γ-secretase complex, which cleaves amyloid precursor protein to produce amyloid-ß (Aß), the major cause of AD. Presenilin enhancer 2 (Pen2) is critical for activating γ-secretase and exporting PS1 from endoplasmic reticulum (ER). Among all the familial AD-linked PS1 mutations, mutations at the G206 amino acid are the most adjacent position to the Pen2 binding site. Here, we characterized the effect of a familial AD-linked PS1 G206D mutation on the PS1-Pen2 interaction and the accompanied alteration in γ-secretase-dependent and -independent functions. We found that the G206D mutation reduced PS1-Pen2 interaction, but did not abolish γ-secretase formation and PS1 endoproteolysis. For γ-secretase-dependent function, the G206D mutation increased Aß42 production but not Notch cleavage. For γ-secretase-independent function, this mutation disrupted the ER calcium homeostasis but not lysosomal calcium homeostasis and autophagosome maturation. Impaired ER calcium homeostasis may due to the reduced mutant PS1 level in the ER. Although this mutation did not alter the cell survival under stress, both increased Aß42 ratio and disturbed ER calcium regulation could be the mechanisms underlying the pathogenesis of the familial AD-linked PS1 G206D mutation.

P-cresol induces disruption of cardiomyocyte adherens junctions.

Higher serum levels of p-cresol in chronic kidney disease populations have been associated with increased cardiovascular mortality. However, studies on how p-cresol affects intercellular junctions between cardiomyocytes were limited. This study investigated the effect of p-cresol on adherens junction (AJ) of neonatal cultured cardiomyocytes and its underlying mechanism. A loss of N-cadherin and p120-catenin (p120ctn) immunostaining from cell-cell contact sites was noted by p-cresol treatment. In addition, p-cresol disrupted AJs by inducing formation of intercellular gaps. Our previous study has revealed that p-cresol increased intracellular calcium levels and activated protein kinase Cα (PKCα) by phosphorylation. The PKCα activation was involved in the p-cresol-mediated AJ disassembly, since pharmacological inhibition of PKCα abolished the above-mentioned p-cresol effect. This PKCα activation also led to the serine dephosphorylation of p120ctn and caused the dissociation of p120ctn from N-cadherin. This hypothesis was further confirmed in H9c2 cells by siRNA approach. SiRNA knockdown of PKCα prevented p-cresol-induced serine dephosphorylation of p120ctn and splitting of AJ. In conclusion, p-cresol caused PKCα-dependent AJ disassembly of cardiomyocytes, which might be related to asychronized contraction.

Uremic toxin p-cresol induces disassembly of gap junctions of cardiomyocytes.

High serum levels of p-cresol have been associated with cardiovascular diseases. This study investigated the effects of p-cresol on gap junctions in neonatal cultured cardiomyocytes. p-Cresol reduced the spontaneous contraction rates of cardiomyocytes, and caused irregular cardiomyocyte beating. Junctional connexin 43 (Cx43) plaques became smaller in size and the gap junction intercellular communication (GJIC) impaired. Moreover, p-cresol increased intracellular Ca(+2) levels, and induced Ca(+2)-dependent protein kinase Cα (PKCα) activation. p-Cresol decreased P1 and P2 Cx43 levels, and increased non-phosphorylated S368-Cx43 levels. The above changes as well as Cx43 disassembly and GJIC decrease induced by p-cresol were prevented by the BAPTA-AM or PKCα inhibitor Gö6976. These results suggest that PKCα mediates p-cresol-induced gap junction disassembly and GJIC dysfunction via S368-Cx43 serine dephosphorylation. This hypothesis was further confirmed in H9c2 cells by siRNA approach. SiRNA knockdown of PKCα prevented p-cresol-induced increase in nonphosphorylated Cx43. This finding supports the association of p-cresol and cardiovascular diseases.

Effects of indoxyl sulfate on adherens junctions of endothelial cells and the underlying signaling mechanism.

Uremic patients have a much higher risk of cardiovascular diseases and death. Uremic toxins are probably involved in the development of vascular endothelial dysfunction. Indoxyl sulfate (IS) is a uremic toxin that accumulates with deterioration of renal function. This study explored the effects of IS on the adherens junctions of vascular endothelial cells and revealed the underlying mechanism. Bovine pulmonary artery endothelial cells (BPAECs) were treated with IS, and the distribution of vascular endothelial cadherin (VE-cadherin), p120-catenin, ß-catenin, and stress fibers was examined by immunofluorescence. IS treatment resulted in disruption of intercellular contacts between BPAECs with prominent parallel-oriented intracellular stress fiber formation. Intracellular free radical levels which measured by flow cytometry increased after IS treatment. The antioxidant, MnTMPyP, and an ERK pathway inhibitor, U0126, both significantly prevented IS-induced disruption of intercellular contacts. Western blotting analyses demonstrated that IS-induced phosphorylation of myosin light chain kinase (MLCK) and myosin light chains (MLC) as well as activation of extracellular-signal-regulated protein kinase (ERK1/ERK2). Pretreatment with MnTMPyP prevented ERK1/2 phosphorylation. U0126 prevented the IS-induced MLCK and MLC phosphorylation. MEK-ERK acted as the upstream regulator of the MLCK-MLC pathway. These findings suggest that the superoxide anion-MEK-ERK-MLCK-MLC signaling mediates IS-induced junctional dispersal of BPAECs.

Cordycepin induces apoptosis of CGTH W-2 thyroid carcinoma cells through the calcium-calpain-caspase 7-PARP pathway.

Cordycepin, a nucleoside isolated from Cordyceps sinensis, is an inhibitor of polyadenylation and has an antitumor effect. We used CGTH W-2, a follicular thyroid carcinoma cell line, to study the mechanism of the anticancer effect of cordycepin. Cordycepin decreased cell viability and resulted in apoptosis but not necrosis. Cordycepin increased intracellular calcium levels triggering calpain activation, which led to apoptosis. BAPTA/AM and calpeptin inhibited the cordycepin-induced cleavage of caspase 7 and poly (ADP-ribose) polymerase (PARP), implying an upstream role of calcium and calpain. CGTH W-2 cells expressed four subtypes of adenosine receptors (AR), A1AR, A2AAR, A2BAR, and A3AR. Specific antagonists to AR subtypes all blocked cordycepin-induced apoptosis to different degrees. Small interfering RNA for A1AR and A3AR abrogated cordycepin-induced apoptosis. In conclusion, the cordycepin-induced apoptosis of CGTH W-2 cells is mediated by the calcium-calpain-caspase 7-PARP pathway, and ARs are involved in the apoptotic effect of cordycepin.