Multi-omics profiling of PC-3 cells reveals bufadienolides-induced lipid metabolic remodeling by regulating long-chain lipids synthesis and hydrolysis.

INTRODUCTION: Lipid metabolism participates in various biological processes such as proliferation, apoptosis, migration, invasion, and maintenance of membrane homeostasis of prostate tumor cells. Bufadienolides, the active ingredients of Chansu, show a robust anti-proliferative effect against prostate cancer cells in vitro, but whether bufadienolides could regulate the lipid metabolism in prostate cancer has not been evaluated. OBJECTIVES: Our study explored the regulatory effects of bufadienolides on lipid metabolism in human prostate carcinoma cells (PC-3). METHODS: Untargeted lipidomics and transcriptomics were combined to study the effect of different bufadienolides interventions on lipid and gene changes of PC-3 cells. The key genes related to lipid metabolism and prostate cancer development were verified by qPCR and western blotting. RESULTS: Lipidomic analysis showed that the active bufadienolides significantly downregulated the content of long-chain lipids of PC-3 cells. Based on transcriptomic and qPCR analyses, many genes related to lipid metabolism were significantly regulated by active bufadienolides, such as ELOVL6, CYP2E1, GAL3ST1, CERS1, PLA2G10, PLD1, SPTLC3, and GPX2. Bioinformatics analysis of the Cancer Genome Atlas database and literature retrieval showed that elongation of very long-chain fatty acids protein 6 (ELOVL6) and phospholipase D1 (PLD1) might be important regulatory genes. Western blot analysis revealed that active bufadienolides could downregulate PLD1 protein levels which might promote anti-prostate cancer effect. CONCLUSIONS: All these findings support that bufadienolides might induce lipid metabolic remodeling by regulating long-chain lipids synthesis and phospholipid hydrolysis to achieve an anti-prostate cancer effect, and PLD1 would probably be the key protein.

Classification, application, multifarious activities and production improvement of lipopeptides produced by Bacillus.

Lipopeptides, a class of compounds consisting of a peptide ring and a fatty acid chain, are secondary metabolites produced by Bacillus spp. As their hydrophilic and oleophilic properties, lipopeptides are widely used in food, medicine, environment and other industrial or agricultural fields. Compared with artificial synthetic surfactants, microbial lipopeptides have the advantages of low toxicity, high efficiency and versatility, resulting in urgent market demand and broad development prospect of lipopeptides. However, due to the complex metabolic network and precursor requirements of synthesis, the specific and strict synthesis pathway, and the coexistence of multiple homologous substances, the production of lipopeptides by microorganisms has the problems of high cost and low production efficiency, limiting the mass production of lipopeptides and large-scale application in industry. This review summarizes the types of Bacillus-produced lipopeptides and their biosynthetic pathways, introduces the versatility of lipopeptides, and describes the methods to improve the production of lipopeptides, including genetic engineering and optimization of fermentation conditions.

Unveiling the Hydration Structure of Ferrihydrite for Hole Storage in Photoelectrochemical Water Oxidation.

Ferrihydrite (Fh) has been demonstrated acting as a hole-storage layer (HSL) in photoelectrocatalysis system. However, the intrinsic structure responsible for the hole storage function for Fh remains unclear. Herein, by dehydrating the Fh via a careful calcination, the essential relation between the HSL function and the structure evolution of Fh material is unraveled. The irreversible and gradual loss of crystal water molecules in Fh leads to the weakening of the HSL function, accompanied with the arrangement of inner structure units. A structure evolution of the dehydration process is proposed and the primary active structure of Fh for HSL is identified as the [FeO6 ] polyhedral units bonding with two or three molecules of crystal water. With the successive loss of chemical crystal water, the coordination symmetry of [FeO6 ] hydration units undergoes mutation and a more ordered structure is formed, causing the difficulty for accepting photogenerated holes as a consequence.

Hole-Storage Enhanced a-Si Photocathodes for Efficient Hydrogen Production.

Ferrihydrite (Fh) has been demonstrated as an effective interfacial layer for photoanodes to achieve outstanding photoelectrochemical (PEC) performance for water oxidation reaction owing to its unique hole-storage function. However, it is unknown whether such a hole-storage layer can be used to construct highly efficient photocathodes for hydrogen evolution reaction (HER). In this work, we report Fh interfacial engineering of amorphous silicon photocathode (with nickel as HER cocatalyst) achieving a photocurrent density of 15.6 mA cm-2 at 0 V vs. the reversible hydrogen electrode and a half-cell energy conversion efficiency of 4.08 % in alkaline solution, outperforming most of reported a-Si based photocathodes including multi-junction configurations integrated with noble metal cocatalysts in acid solution. Besides, the photocurrent density is maintained above 14 mA cm-2 for 175 min with 100 % Faradaic efficiency for HER in alkaline solution. Our results demonstrate a feasible approach to construct efficient photocathodes via the application of a hole-storage layer.

Transition-Metal-Based Electrocatalysts as Cocatalysts for Photoelectrochemical Water Splitting: A Mini Review.

Converting solar energy into hydrogen via photoelectrochemical (PEC) water splitting is one of the most promising approaches for a sustainable energy supply. Highly active, cost-effective, and robust photoelectrodes are undoubtedly crucial for the PEC technology. To achieve this goal, transition-metal-based electrocatalysts have been widely used as cocatalysts to improve the performance of PEC cells for water splitting. Herein, this Review summarizes the recent progresses of the design, synthesis, and application of transition-metal-based electrocatalysts as cocatalysts for PEC water splitting. Mo, Ni, Co-based electrocatalysts for the hydrogen evolution reaction (HER) and Co, Ni, Fe-based electrocatalysts for the oxygen evolution reaction (OER) are emphasized as cocatalysts for efficient PEC HER and OER, respectively. Particularly, some most efficient and robust photoelectrode systems with record photocurrent density or durability for the half reactions of HER and OER are highlighted and discussed. In addition, the self-biased PEC devices with high solar-to-hydrogen efficiency based on earth-abundant materials are also addressed. Finally, this Review is concluded with a summary and remarks on some challenges and opportunities for the further development of transition-metal-based electrocatalysts as cocatalysts for PEC water splitting.

Antagonistic activities of volatiles produced by two Bacillus strains against Monilinia fructicola in peach fruit.

BACKGROUND: Brown rot caused by Monilinia fructicola is one of most serious diseases of postharvest peach fruit. The objective of this study was to select effective antagonistic bacteria against Monilinia fructicola and evaluate the effects of these strains against brown rot. RESULTS: Four bacterial strains producing inhibitory volatile gas against Monilinia fructicola were isolated from the peach rhizosphere soil. The volatiles produced by 12a (Bacillus vallismortis) and 14b (Bacillus altitudinis) showed considerable antagonistic activities. Monilinia fructicola showed 80.3% and 68.4% mycelial growth inhibition and cell damage in the presence of strains 12a and 14b, respectively. The inhibition rate of brown rot in peach fruit fumigated with the culture solution of 12a or 14b reached 77.1% and 50.0%, respectively. The volatile compounds produced by 12a and 14b were identified according to gas chromatographic-mass spectrometric analysis. Among them, 6-methyl-2-heptanone and 2-pentylfuran completely inhibited mycelial growth at 100 µL L-1 concentration. Cedrol showed strong inhibitory activity against mycelial growth at 100 µg L-1 and isodecyl methacrylate inhibited growth at high concentration. The inhibition rate of the 50 µL L-1 artificial mixture of these four volatiles was 59.3% in vitro. CONCLUSION: These results indicate that the two antagonistic bacteria and some volatiles produced by them have potential value in controlling brown rot in harvested peach fruit. © 2018 Society of Chemical Industry.

Exogenous nitric oxide induces disease resistance against Monilinia fructicola through activating the phenylpropanoid pathway in peach fruit.

BACKGROUND: Nitric oxide (NO) is a multifunctional signaling molecule involved in plant-induced resistance to disease. The present study aimed to investigate the relationship between disease resistance induced by NO and the phenylpropanoid pathway in peach fruit. The present study investigated the effect of NO on the main enzymes and metabolites of the phenylpropanoid pathway of harvested peach, which are probably related to disease resistance against Monilinia fructicola. RESULTS: The results showed that treatment with 15 µmol L-1 NO significantly (P < 0.05) enhanced the activities of phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, 4-coumaroyl-CoA ligase, chalcone synthase and chalcone isomerase and the expression of their genes. Furthermore, NO treatment significantly (P < 0.05) increased the contents of total phenolics, flavonoids and lignin over the entire storage period and maintained higher total anthocyanin, phenolic acid and anthocyanin contents during the earlier storage period. CONCLUSION: These results suggest that NO treatment could activate the phenylpropanoid pathway to enhance the activity of related enzymes and the contents of phenylpropanoid metabolites in peach to improve disease resistance and prevent pathogenic invasion. © 2016 Society of Chemical Industry.

Manipulating the Interfacial Energetics of n-type Silicon Photoanode for Efficient Water Oxidation.

The photoanodes with heterojunction behavior could enable the development of solar energy conversion, but their performance largely suffers from the poor charge separation and transport process through the multiple interfacial energy levels involved. The question is how to efficiently manipulate these energy levels. Taking the n-Si Schottky photoanode as a prototype, the undesired donor-like interfacial defects and its adverse effects on charge transfer in n-Si/ITO photoanode are well recognized and diminished through the treatment on electronic energy level. The obtained n-Si/TiOx/ITO Schottky junction exhibits a highly efficient charge transport and a barrier height of 0.95 eV, which is close to the theoretical optimum for n-Si/ITO Schottky contact. Then, the holes extraction can be further facilitated through the variation of surface energy level, with the NiOOH coated ITO layer. This is confirmed by a 115% increase in surface photovoltage of the photoanodes. Eventually, an unprecedentedly low onset potential of 0.9 V (vs RHE) is realized for water oxidation among n-Si photoanodes. For the water oxidation reaction, the n-Si/TiOx/ITO/NiOOH photoanode presents a charge separation efficiency up to 100% and an injection efficiency greater than 90% at a wide voltage range. This work identifies the important role of interfacial energetics played in photoelectrochemical conversion.

Photoassisted Oxygen Reduction Reaction in H2 -O2 Fuel Cells.

The oxygen reduction reaction (ORR) is a key step in H2 -O2 fuel cells, which, however, suffers from slow kinetics even for state-of-the-art catalysts. In this work, by making use of photocatalysis, the ORR was significantly accelerated with a polymer semiconductor (polyterthiophene). The onset potential underwent a positive shift from 0.66 to 1.34 V, and the current was enhanced by a factor of 44 at 0.6 V. The improvement was further confirmed in a proof-of-concept light-driven H2 -O2 fuel cell, in which the open circuit voltage (Voc ) increased from 0.64 to 1.18 V, and the short circuit current (Jsc ) was doubled. This novel tandem structure combining a polymer solar cell and a fuel cell enables the simultaneous utilization of photo- and electrochemical energy, showing promising potential for applications in energy conversion and storage.

Efficient Hole Extraction from a Hole-Storage-Layer-Stabilized Tantalum Nitride Photoanode for Solar Water Splitting.

One of the major hurdles that impedes the practical application of photoelectrochemical (PEC) water splitting is the lack of stable photoanodes with low onset potentials. Here, we report that the Ni(OH)x/MoO3 bilayer, acting as a hole-storage layer (HSL), efficiently harvests and stores holes from Ta3N5, resulting in at least 24 h of sustained water oxidation at the otherwise unstable Ta3N5 electrode and inducing a large cathodic shift of ≈600 mV in the onset potential of the Ta3N5 electrode.

A facile two-step method for fabrication of plate-like WO3 photoanode under mild conditions.

Fabrication of photoelectrodes on a large-scale, with low-cost and high efficiency is a challenge for their practical application in photoelectrochemical (PEC) water splitting. In this work, a typical plate-like WO(3) photoanode was fabricated with chemical etching of the as-prepared mixed tungsten-metal oxides (W-M-O, M = Cu, Zn or Al) by a reactive magnetron co-sputtering technique, which results in a greatly enhanced PEC performance for water oxidation in comparison with that obtained from a conventional magnetron sputtering method. The current approach is applicable for the fabrication of some other semiconductor photoelectrodes and is promising for the scaling up of applications for highly efficient solar energy conversion systems.

Solar-to-hydrogen efficiency exceeding 2.5% achieved for overall water splitting with an all earth-abundant dual-photoelectrode.

The solar-to-hydrogen (STH) efficiency of a traditional mono-photoelectrode photoelectrochemical water splitting system has long been limited as large external bias is required. Herein, overall water splitting with STH efficiency exceeding 2.5% was achieved using a self-biased photoelectrochemical-photovoltaic coupled system consisting of an all earth-abundant photoanode and a Si-solar-cell-based photocathode connected in series under parallel illumination. We found that parallel irradiation mode shows higher efficiency than tandem illumination especially for photoanodes with a wide light absorption range, probably as the driving force for water splitting reaction is larger and the photovoltage loss is smaller in the former. This work essentially takes advantage of a tandem solar cell which can enhance the solar-to-electricity efficiency from another point of view.

Hydrogen sulfide extends the postharvest life and enhances antioxidant activity of kiwifruit during storage.

BACKGROUND: Exogenous hydrogen sulfide (H2S) treatment can prolong the postharvest life of cut flowers and strawberries. Little work has been done to explore the effects of H2S on respiratory climacteric fruits such as kiwifruits during storage. Therefore the aim of the present study was to evaluate the effects of H2S treatment at concentrations of 15­1000 µmol L⁻¹ on the postharvest life of kiwifruit during 25 °C storage and the role of H2S in regulating the antioxidant defensive system of kiwifruit. RESULTS: Treatments with 45 and 90 µmol L⁻¹ H2S significantly inhibited the increase in soluble sugar content and the decrease in vitamin C (Vit C), chlorophyll content and firmness, inhibited ethylene production and both superoxide production rate (O(·2)⁻) and hydrogen peroxide content. Kiwifruits with 45 and 90 µmol L⁻¹ H2S exhibited significantly higher activities of superoxide dismutase, catalase and peroxidase. Treatment with 180 µmol L⁻¹ H2S promoted the ripening of kiwifruits. CONCLUSION: Treatments with 45 and 90 µmol L⁻¹ H2S could delay the maturation and senescence of kiwifruits and maintain higher titratable acid (TA) and Vit C during eating-ripe storage by inhibiting ethylene production, improving protective enzyme activities and decreasing the accumulation of reactive oxygen species to protect the cell membrane during storage.

A tantalum nitride photoanode modified with a hole-storage layer for highly stable solar water splitting.

Photoelectrochemical (PEC) water splitting is an ideal approach for renewable solar fuel production. One of the major problems is that narrow bandgap semiconductors, such as tantalum nitride, though possessing desirable band alignment for water splitting, suffer from poor photostability for water oxidation. For the first time it is shown that the presence of a ferrihydrite layer permits sustainable water oxidation at the tantalum nitride photoanode for at least 6 h with a benchmark photocurrent over 5 mA cm(-2) , whereas the bare photoanode rapidly degrades within minutes. The remarkably enhanced photostability stems from the ferrihydrite, which acts as a hole-storage layer. Furthermore, this work demonstrates that it can be a general strategy for protecting narrow bandgap semiconductors against photocorrosion in solar water splitting.

Hyaluronic acid modified extracellular vesicles targeting hepatic stellate cells to attenuate hepatic fibrosis.

RATIONALE: Transforming growth factor-beta1 (TGF-ß1) plays a pivotal role in promoting hepatic fibrosis, pirfenidone (PFD) could inhibit TGF-ß1 signaling pathway to alleviate hepatic stellate cells (HSC) activation mediated hepatic fibrosis. The targeting delivery strategy of PFD to hepatic stellate cells is a challenge. Extracellular vesicles (EVs), cell-derived membranous particles are intraluminal nano-vesicles that play a vital role in intercellular communication, they also be considered as an ideal nano-carrier. METHODS: In this study, we developed a target strategy to deliver PFD to HSC with CD44 over-expression by EVs, hyaluronic acid (HA) modified DSPE-PEG2000 endows the active targeting ability of activated HSCs to PFD-loaded EVs. RESULTS: In both rat hepatic stellate cell line HSC-T6 and rat hepatocyte cell line BRL, HA@EVs-PFD demonstrated the capacity to down-regulate the expression of collagen-synthesis-related proteins and showed superior inhibition efficacy of HSC-T6 activation compared to free PFD. In hepatic fibrosis model, 4 weeks of HA@EVs-PFD treatment resulted in a reduction in liver collagen fibers, significant improvement in hepatic cell morphology, and amelioration of hepatic fibrosis. CONCLUSIONS: HA@EVs-PFD, as a drug delivery system that effectively targets and inhibits activated HSCs to treat hepatic fibrosis, holds promise as a potential therapeutic agent against hepatic fibrosis.

Visible light driven overall water splitting using cocatalyst/BiVO4 photoanode with minimized bias.

BiVO4 and many other semiconductor materials are ideal visible light responsive semiconductors, but are insufficient for overall water splitting. Upon loading water oxidation cocatalyst, for example Co-borate (denoted as CoBi) used here, onto BiVO4 photoanode, it is found that not only the onset potential is negatively shifted but also the photocurrent and the stability are significantly improved. And more importantly, PEC overall water splitting to H2 and O2 is realized using CoBi/BiVO4 as photoanode with a rather low applied bias (less than 0.3 V vs. counter electrode) in a two-electrode scheme, while at least 0.6 V is needed for bare BiVO4. This work demonstrates the practical possibility of achieving overall water splitting using the PEC strategy under a bias as low as the theoretical minimum, which is the difference between the flat band and proton reduction potential for a photoanode thermodynamically insufficient for water reduction. As long as the water oxidation overpotential is overcome with an efficient cocatalyst, the applied bias of the whole system is only used for that thermodynamically required for the proton reduction.

Control of Phytophthora nicotianae disease, induction of defense responses and genes expression of papaya fruits treated with Pseudomonas putida MGP1.

BACKGROUND: Biological control is a potential strategy to reduce post-harvest decay in several fruits. Little research has been carried out on the effects of endophytic bacterium on post-harvest blight caused by Phytophthora nicotianae in papaya. In this work, the biocontrol activity of Pseudomonas putida MGP1 on this disease and its possible mechanisms, including changes of defensive enzyme activities, total phenolic content and mRNA levels of two important genes, were investigated. RESULTS: Fruits treated with MGP1 showed a significant lower disease index and demonstrated increases in chitinase, ß-1,3-glucanase, phenylalanine ammonia-lyase, peroxidase, polyphenol oxidase and catalase activities and total phenolic content. In addition, the expression levels of pathogenesis related protein 1 gene (PR1) and non-expressor of PR1 gene (NPR1) in papaya fruits were elevated by MGP1 treatment. CONCLUSION The results indicated that papaya fruits were responsive to the endophytic bacterium Ps. putida, which could activate defensive enzymes and genes and thereby induce host disease resistance.

Development of a novel 1-octen-3-ol-loaded agar/curdlan hydrogel for inhibiting peach fruit diseases.

Our previous study found that 1-octen-3-ol fumigation treatment could effectively induce the resistance of peach fruit diseases. However, 1-octen-3-ol is a liquid fumigant, which is not conducive to storage and application. Herein, the gel of 1 % agar compound with 1 % curdlan was used as a novel material for covering 1-octen-3-ol. The interaction of agar and curdlan was promoted by adding 1-octen-3-ol, leading to a higher thermostability compared to single-component antibacterial gels. Moreover, 1-octen-3-ol resulted in changes in the internal structure and mechanical properties of gel to form a pore-like structure, which is beneficial to the retention and release of 1-octen-3-ol. Additionally, the 2 % agar gel containing 1-octen-3-ol had the best inhibitory effect on the mycelial growth of Monilinia fructicola and Rhizopus stolonifer in vitro, and the compound hydrogel of 1 % agar and 1 % curdlan with 1-octen-3-ol could most effectively inhibit brown rot and soft rot caused by these two pathogens in vivo. Overall, the data indicated that the novel 1-octen-3-ol-loaded agar/curdlan hydrogels could effectively retain and release 1-octen-3-ol, and induce the resistance of peach fruit diseases.

Photocatalytic overall water splitting promoted by an α-ß phase junction on Ga2O3.

When Alpha met Beta: a tuneable α-ß surface phase junction on Ga(2)O(3) can significantly improve photocatalytic overall water splitting into H(2) and O(2) over individual α-Ga(2)O(3) or ß-Ga(2)O(3) surface phases. This enhanced photocatalytic performance is mainly attributed to the efficient charge separation and transfer across the α-ß phase junction.

Coupling effect between hole storage and interfacial charge transfer over ultrathin CoPi-modified hematite photoanodes.

Understanding the functionality of the modification layer in regulating the charge transfer process at the semiconductor/electrolyte interface is of great significance to the rational design of photoelectrocatalytic water oxidation systems. Herein, by systematically investigating and comparing the charge transfer kinetics behaviors over ferrihydrite (Fh)- and cobalt phosphate (CoPi)-modified hematite (Fe2O3) photoanodes, we unveiled the essential relation between photocurrent enhancement and the charge transfer process. With the hole-storage material Fh as a reference, it was found that CoPi demonstrates high hole-storage capacity at a low bias region (<1.0 V vs. RHE) due to the effective release of Fermi level pinning. Afterwards, the stored holes would be timely injected into the electrolyte for water oxidation, caused by the enhanced charge separation in the presence of CoPi. In contrast, the decoration of Fh can only slightly passivate the surface states and promote hole injection in the high potential region. Subsequently, superior hole-storage capacity in the low-potential region is recognized as a crucial factor for photocurrent enhancement. These combined results provide new insights into the understanding of interfacial charge transfer kinetics.