Blood exosome sensing via neuronal insulin-like growth factor-1 regulates autism-related phenotypes.

The development and progression of autism spectrum disorder (ASD) is characterized by multiple complex molecular events, highlighting the importance of the prefrontal brain regions in this process. Exosomes are nanovesicles that play a critical role in intercellular communication. Peripheral systems influence brain function under both physiological and pathological conditions. We investigated whether this influence was mediated by the direct sensing of peripheral blood exosomes by brain cells. Administration of serum exosomes from rats with valproic acid-induced ASD resulted in ASD-related phenotypes in mice, whereas exosomes from normal rats did not exhibit such effects. RNA sequencing and bioinformatics analysis suggested that negative regulation of medial prefrontal cortex (mPFC) insulin-like growth factor 1 (IGF-1) by exosome-derived miR-29b-3p may contribute to these ASD-associated effects. Further evidence showed that miR-29b-3p-enriched exosomes crossed the blood-brain barrier to reach the mPFC, subsequently inducing the suppression of IGF-1 expression in neurons. Optogenetic activation of excitatory neurons in the mPFC improved behavioral abnormalities in exosome-treated mice. The addition of exogenous IGF-1 or inhibition of miR-29b-3p expression in the mPFC also rescued the ASD-related phenotypes in mice. Importantly, administration of miR-29b-3p-enriched serum exosomes from human donors with ASD into the mouse medial prefrontal cortex was sufficient to induce hallmark ASD behaviors. Together, our findings indicate that blood-brain cross-talk is crucial for ASD pathophysiology and that the brain may sense peripheral system changes through exosomes, which could serve as the basis for future neurological therapies.

Potassium alleviates over-reduction of the photosynthetic electron transport chain and helps to maintain photosynthetic function under salt-stress.

Potassium ions enhance photosynthetic tolerance to salt stress. We hypothesized that potassium ions, by minimizing the trans-thylakoid proton diffusion potential difference, can alleviate over-reduction of the photosynthetic electron transport chain and maintain the functionality of the photosynthetic apparatus. This study investigated the effects of exogenous potassium on the transcription level and activity of proteins related to the photosynthetic electron-transport chain of tobacco seedlings under salt stress. Salt stress retarded the growth of seedlings and caused an outflow of potassium ions from the chloroplast. It also lowered qP (indicator of the oxidation state of QA , the primary quinone electron acceptor in Photosystem II (PSII) and YPSII (average photochemical yield of PSII in the light-adapted state) while increasing YNO+NF (nonregulatory energy dissipation in functional and nonfunctional PSII), accompanied by decreased expression of most light-harvesting, energy-transduction, and electron-transport genes. However, exogenous potassium prevented these effects due to NaCl. Interestingly, lincomycin (an inhibitor of the synthesis of chloroplast-encoded proteins in PSII) significantly diminished the alleviation effect of exogenous potassium on salt stress. We attribute the comprehensive NaCl-induced downregulation of transcription and photosynthetic activities to retrograde signaling induced by reactive oxygen species. There probably exist at least two types of retrograde signaling induced by reactive oxygen species, distinguished by their sensitivity to lincomycin. Exogenous potassium appears to exert its primary effect by ameliorating the trans-thylakoid proton diffusion potential difference via a potassium channel, thereby accelerating ATP synthesis and carbon assimilation, alleviating over-reduction of the photosynthetic electron transport chain, and maintaining the functionality of photosynthetic proteins.

Heterologous expression of Zygophyllum xanthoxylon zinc finger protein gene (ZxZF) enhances the tolerance of poplar photosynthetic function to drought stress.

The ZxZF transcription factor (TF) of Zygophyllum xanthoxylon (Bunge) Maxim, an extremely drought-resistant woody plant, is a C2H2 zinc finger protein. Studies have shown that C2H2 zinc finger proteins play important roles in activating stress-related genes and enhancing plant resistance. However, their function in regulating plant photosynthesis under drought stress is not well understood. Since poplar is an important greening and afforestation tree species, it is particularly important to cultivate excellent drought-tolerant varieties. The ZxZF transcription factor (TF) was heterogeneously expressed in Euroamerican poplar (Populus × euroameracana cl.'Bofengl') by genetic transformation. Based on the mechanism and potential function of poplar photosynthesis regulated by ZxZF under drought stress, transcriptomic and physiological determinations were used to reveal the important role of this gene in improving the drought resistance of poplar. The results showed that the overexpression of ZxZF TF in transgenic poplars could improve the inhibition of Calvin cycle by regulating stomatal opening and increasing the concentration of intercellular CO2. The chlorophyll content, photosynthetic performance index, and photochemical efficiency of transgenic lines under drought stress were significantly higher than those of the wild type (WT). The overexpression of ZxZF TFs could alleviate the degree of photoinhibition of photosystems II and I under drought stress and maintain the efficiency of light energy capture and the photosynthetic electron transport chain. The transcriptomic data also showed that differentially expressed genes between the transgenic poplar and WT under drought stress were primarily enriched in metabolic pathways related to photosynthesis, such as photosynthesis, photosynthesis-antenna protein, porphyrin and chlorophyll metabolism, and photosynthetic carbon fixation, and the downregulation of genes related to chlorophyll synthesis, photosynthetic electron transport and Calvin cycle were alleviated. In addition, the overexpression of ZxZF TF can alleviate the inhibition of NADH dehydrogenase-like (NDH) cyclic electron flow of the poplar NDH pathway under drought stress, which plays an important role in reducing the excess pressure of electrons on the photosynthetic electron transport chain and maintaining the normal photosynthetic electron transport. In summary, the overexpression of ZxZF TFs can effectively alleviate the inhibition of drought on the assimilation of carbon in poplar and have a positive impact on light energy capture, the orderly transport of photosynthetic electron transport chain and the integrity of the photosystem, which is highly significant to acheivean in-depth understanding of the function of ZxZF TFs. This also provides an important basis for the breeding of new transgenic poplar varieties.

Trx CDSP32-overexpressing tobacco plants improves cadmium tolerance by modulating antioxidant mechanism.

The effects of overexpression of the thioredoxin-like protein CDSP32 (Trx CDSP32) on reactive oxygen species (ROS) metabolism in tobacco leaves exposed to cadmium (Cd) were studied by combining physiological measures and proteomics technology. Thus, the number of differentially expressed proteins (DEPs) in plants overexpressing the Trx CDSP32 gene in tobacco (OE) was observed to be evidently lower than that in wild-type (WT) tobacco under Cd exposure, especially the number of down-regulated DEPs. Cd exposure induced disordered ROS metabolism in tobacco leaves. Although Cd exposure inhibited the activities of superoxide dismutase (SOD), catalase (CAT), and l-ascorbate peroxidase (APX) and the expression of proteins related to the thioredoxin-peroxiredoxin (Trx-Prx) pathway, the increase in the activities of peroxidase (POD), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione peroxidase (GPX), and glutathione S-transferase (GST) and their protein expression levels played an important role in the physiological response to Cd exposure. Notably, Trx CDSP32 was observed to alleviate the decrease in the expression and activities of SOD and CAT caused by Cd exposure and enhance the function of POD. Trx CDSP32 was observed to increase the H2O2 scavenging capacity of the ascorbic acid-glutathione (AsA-GSH) cycle and Trx-Prx pathway under Cd exposure, and it can especially regulate 2-Cys peroxiredoxin (2-Cys Prx) protein expression and thioredoxin peroxidase (TPX) activity. Thus, overexpression of the Trx CDSP32 gene can alleviate the oxidative damage that occurs in tobacco leaves under Cd exposure by modulating antioxidant defense systems.

Potassium ion regulates hormone, Ca2+ and H2O2 signal transduction and antioxidant activities to improve salt stress resistance in tobacco.

Although improvement of plant salt tolerance by potassium ions (K+) has been widely studied, whether the tolerance is mediated via hormone signaling or antioxidant systems remains to be explored. This study combined plant physiology with transcriptomic techniques to study how K+ interacts with hormones and antioxidant enzymes to improve plant salt tolerance. Tobacco was used as the test material to study the effects of exogenous potassium application on photosynthetic function, hormone signal transduction, and reactive oxygen species (ROS) production under NaCl stress. The study also evaluated the function of the Ca2+ signaling pathway in salt stress tolerance. Transcriptome data showed that 4413 up-regulated genes and 3743 down-regulated genes were found in tobacco leaves treated with NaCl compared with the control. Compared with NaCl, the down-regulated genes in tobacco leaves were significantly reduced under NaCl + KCL treatment. The results showed that NaCl stress caused oxidative damage to tobacco leaves due to increased superoxide anion (O2-) content, superoxide dismutase (SOD) dismutates superoxide anion to produce hydrogen peroxide and the accumulation of H2O2 caused by reduced ascorbate peroxidase (APX) and peroxidase (POD) activities. NaCl stress also increased abscisic acid (ABA) content in tobacco leaves, resulting in stomatal closure and reduced photosynthetic capacity. Transcriptome data showed that 5 SOD, 1 POD, 1 CAT, 5 APX, and 3 GPX genes were significantly down-regulated by the NaCl treatment. Contrarily, NaCl + KCl treatment reduced the accumulation of O2-and SOD activity but increased POD activity, thereby reducing the accumulation of H2O2 and alleviating oxidative damage. The expression of 2 SOD and 3 APX and 2 GPX genes was significantly higher in NaCl + KCl treatment than that in NaCl treatment. Sufficient K+ also increased indole acetic acid (IAA) levels in tobacco leaves under NaCl stress but reduced ABA content, promoting stomatal opening and improving the photosynthetic capacity. In conclusion, K+ can improve plant salt tolerance by alleviating oxidative damage and regulating hormone signal transduction.

Incentive Mechanisms for Carbon Emission Abatement Considering Consumers' Low-Carbon Awareness under Cap-and-Trade Regulation.

In the era of sustainable development, reducing carbon emissions and achieving carbon neutrality are gradually becoming a consensus for our society. This study explores firms' incentive mechanisms for carbon emission abatement in a two-echelon supply chain under cap-and-trade regulation, where consumers exhibit low-carbon awareness. To boost the manufacturer's motivation for abatement, the retailer can provide four incentive strategies, i.e., price-only (PO), cost-sharing (CS), revenue-sharing (RS), and both (cost and revenue) sharing (BS). The equilibrium decisions under the four incentive strategies are obtained by establishing and solving game models. A two-part tariff contract is also proposed to coordinate the low-carbon supply chain. Finally, through comparisons and analyses, we find that: (1) Consumers' high low-carbon awareness can boost the manufacturer's incentive for carbon emission abatement (CEA), thus increasing supply chain members' profits. (2) It is more effective for the retailer to share its revenue to incentivize the manufacturer for abatement than to bear the investment cost of CEA. Thus, Strategy RS is better than Strategy CS and equivalent to Strategy BS. (3) The manufacturer and retailer have consistent incentive strategy preference under cap-and-trade regulation. Both firms prefer the incentive strategy with a higher cooperation level. (4) The incentive strategy with a higher cooperation level can also bring higher eco-social welfare under certain conditions.

Cathode Design Optimization toward the Wide-Pressure-Range Miniature Discharge Ion Source for a Vacuum Micropump.

It is difficult to generate and maintain the vacuum level in vacuum MEMS (Micro-Electro-Mechanical Systems) devices. Currently, there is still no single method or device capable of generating and maintaining the desired vacuum level in a vacuum device for a long time. This paper proposed a new wide-pressure-range miniature ion source, which can be applied to a vacuum micropump. The miniature ion source consists only of silicon electrodes and a glass substrate. Its operating pressure range covers seven orders of magnitude, starting from atmospheric pressure, a promising solution to the difficulty. Based on the principle of gas discharge, the ion source features a simple two-electrode structure with a two-stage electrode spacing, operating under DC voltage excitation. The first-stage electrode spacing of the ion source is small enough to ensure that it starts working at atmospheric pressure down to a certain reduced pressure when it automatically switches to discharge at the larger second-stage electrode spacing and operates from that pressure down to a high vacuum. Two configurations of the ion source have been tested: without-magnet, operating from atmospheric pressure down to 1 mbar; and with-magnet, operating from atmospheric pressure to 10-4 mbar, which covers seven orders of magnitude of pressure. The ion source can be applied not only to a MEMS ion pump to meet demands of a variety of vacuum MEMS devices, but can also be applied to other devices, such as vacuum microgauges and mass spectrometers.

A-Site Ordered Double Perovskite with in Situ Exsolved Core-Shell Nanoparticles as Anode for Solid Oxide Fuel Cells.

A highly active anode material for solid oxide fuel cells resistant to carbon deposition is developed. Co-Fe co-doped La0.5Ba0.5MnO3-δ with a cubic-hexagonal heterogeneous stucture is synthesized through the Pechini method. An A-site ordered double perovskite with Co0.94Fe0.06 alloy-oxide core-shell nanoparticles on its surface is formed after reduction. The phase transition and the exsolution of the nanoparticles are investigated with X-ray diffraction, thermogravimetric analysis, and high-resolution transmission electron microscope. The exsolved nanoparticles with the layered double-perovskite supporter show a high catalytic activity. A single cell with that anode and a 300 µm thick La0.8Sr0.2Ga0.8Mg0.2O3-δ electrolyte layer exhibits maximum power densities of 1479 and 503 mW cm-2 at 850 °C with wet hydrogen and wet methane fuels, respectively. Moreover, the single cell fed with wet methane exhibits a stable power output at 850 °C for 200 h, demonstrating a high resistance to carbon deposition of the anode due to the strong anchor of the exsolved nanoparticles on the perovskite parent. The oxide shell also preserves the metal particles from coking.

Rapid mass spectrometry analysis of a rectilinear ion trap by continuous secular frequency scanning.

RATIONALE: Secular frequency scanning is a mass spectrometry (MS) analysis method in which the frequency of the auxiliary alternating current (AC) signal is scanned. It has low requirements for radio-frequency (RF) power, which is beneficial for the miniaturization of the mass spectrometer. In this study, the MS performance in the reverse secular frequency scanning (RSFS) mode is optimized for a rectilinear ion trap (RIT), and a method for rapid MS analysis using continuous secular frequency scanning (CSFS) is proposed. METHODS: A RIT mass spectrometer with an auxiliary AC frequency scanning function was built. The resolution, tandem mass spectrometry (MS/MS) and quantitation capability in the RSFS mode were characterized and optimized. Operation in the CSFS mode was then performed by scanning the frequency of the auxiliary AC signal continuously and periodically while maintaining the RF signal and the front Z electrode in the ion injection state, so that the ion injection and cooling were performed at the same time as the mass analysis. RESULTS: With this system, the RSFS mode achieved unit mass resolution at 332 Th, and the MS/MS analysis was completed without changing the RF amplitude at q = 0.4583 for reserpine. The limit of quantitation for imatinib was about 250 ng/mL with the determination coefficient R2  = 0.9981. In the CSFS mode, a single analysis cycle of less than 20 ms could be achieved, which is 14 times faster than the traditional sweep modes. In addition, 100% ion utilization can theoretically be achieved in the CSFS mode. CONCLUSIONS: The CSFS mode is different from the traditional phased sequential operation mode of an ion trap mass spectrometer. By periodic scanning of the auxiliary AC frequency while maintaining ion injection, it is possible to improve the analysis efficiency of the mass spectrometer, which has the prospect of useful application in the field of rapid MS monitoring. Copyright © 2017 John Wiley & Sons, Ltd.