Tuning the crystallinity of the MnOx catalysts to promote toluene catalytic oxidation.

In this paper, the MnOx catalysts with excellent toluene oxidation performance were prepared by a simple precipitation method. The physicochemical properties of the prepared MnOx catalysts were investigated by XRD, BET, H2-TPR, O2-TPD and XPS. The obtained results revealed that the crystallinity of the prepared MnOx catalysts could be effectively regulated by changing the (NH4)2CO3/Mn(NO3)2 molar ratio, and thus affecting the oxygen vacancy concentration of the prepared MnOx catalysts. The prepared MnOx-4 catalyst with the (NH4)2CO3/Mn(NO3)2 molar ratio of 4.0 had the poor crystallinity and small grain size, which effectively promoted the oxygen defects in the MnOx catalyst to be formed. At the same time, the MnOx-4 catalyst had a large specific surface area, the highest low temperature reducibility and the largest number of oxygen vacancies and surface adsorbed oxygen species, which allowed more surface oxygen species to participate in the redox reaction, and promoted the toluene deep oxidation. Therefore, when the (NH4)2CO3/Mn(NO3)2 molar ratio was 4.0, the prepared MnOx-4 catalyst exhibited an excellent toluene catalytic oxidation performance and robust catalytic stability. What's more, the toluene oxidation conversion on the MnOx-4 catalyst reached 99% at 230°C, and the MnOx-4 catalyst showed excellent resistance to water vapour.

Proteomic analysis of Biliverdin protected cerebral ischemia-reperfusion injury in rats.

Biliverdin, a heme metabolite, has been previously reported to alleviate cerebral ischemic reperfusion injury (CIRI). However, the alterations of brain proteome profiles underlying this treatment remain elusive. The objective of this study is to analyze the differential protein expression profile in cerebral cortex of rats involved in anti-CIRI effects of Biliverdin, providing experimental foundation for searching specific marker proteins. Rat model of MCAO/R was established, HE staining, TTC staining, TUNEL staining, and neurological behavioral examination, corner turning test, adhesive removal test, were performed to validate the effects of Biliverdin, and the results indicated that Biliverdin plays a significant role in alleviating CIRI. Furthermore, proteomic analysis of brain tissues of rats subjected to CIRI following Biliverdin treatment was performed using an integrated TMT-based quantitative proteomic approach coupled with LC-MS/MS technology to clarify the comprehensive mechanisms of Biliverdin in CIRI. First, we conducted strict quality control data for TMT experiments. Finally, a total of 7366 proteins were identified, of which 95 proteins were differentially expressed (DEPs) between the CIRI group and the Sham group and 52 between the CIRI and BV groups. In addition, two overlapping proteins among the 147 DEPs, Atg4c and Camlg, were validated by RT-qPCR and western blotting, and their levels were consistent with the results of TMT analysis. Taken together, the current findings firstly mapped comprehensive proteomic changes after CIRI treated with Biliverdin, providing a foundation for developing potentially therapeutic targets of anti-CIRI of Biliverdin and clinically prognostic biomarkers of stroke.

Activated carbon with high mesopore ratio derived from waste Zanthoxylum bungeanum branches by KNO3-assisted H3PO4 staged activation for toluene adsorption.

Waste Zanthoxylum bungeanum branches were used to prepare activated carbon adsorbents with high mesopore ratio by H3PO4 staged activation method with adding KNO3 additive. The prepared activated carbon adsorbents were characterized by SEM, BET, FT-IR, and XRD. The adsorption properties of the prepared activated carbon adsorbents were evaluated by the toluene adsorption/desorption in air. The quasi-first-order, quasi-second-order, and Bangham models were used to fit the obtained toluene adsorption results. The oxidative etching of KNO3 additive improved the pore-forming ability of the H3PO4 activator to enhance the activation pore-forming effects of the selected biomass raw material. The secondary pore-forming effects of K atoms promoted the effective expansion of the pore diameter in the activated carbon preparation process to prepare activated carbon adsorbents with high mesopore proportion. The specific surface area and mesopore proportion of the activated carbon adsorbents prepared by adding KNO3 additive exceeded 1100 m2/g and 71.00%, respectively, and the toluene adsorption capacity exceeded 370.00 mg/g. The rich mesopore structures can effectively reduce the toluene mass transfer resistance, which can promote the corresponding activated carbon adsorbent to be regenerated by low-temperature (40 °C) thermal desorption. The toluene adsorption on the prepared activated carbon adsorbents includes surface adsorption and diffusion in pore structures, and the toluene adsorption mechanism is more consistent with the Bangham kinetic model.

Biliverdin modulates the Nrf2/A20/eEF1A2 axis to alleviate cerebral ischemia-reperfusion injury by inhibiting pyroptosis.

This study aimed to examine whether Biliverdin, which is a common metabolite of haem, can alleviate cerebral ischemia reperfusion injury (CIRI) by inhibiting pyroptosis. Here, CIRI was induced by middle cerebral artery occlusion-reperfusion (MCAO/R) in C57BL/6 J mice and modelled by oxygen and glucose deprivation/reoxygenation (OGD/R) in HT22 cells, it was treated with or without Biliverdin. The spatiotemporal expression of GSDMD-N and infarction volumes were assessed by immunofluorescence staining and triphenyltetrazolium chloride (TTC), respectively. The NLRP3/Caspase-1/GSDMD pathway, which is central to the pyroptosis process, as well as the expression of Nrf2, A20, and eEF1A2 were determined by Western-blots. Nrf2, A20, and eEF1A2 interactions were verified using dual-luciferase reporter assays, chromatin immunoprecipitation, or co-immunoprecipitation. Additionally, the role of Nrf2/A20/eEF1A2 axis in modulating the neuroprotective properties of Biliverdin was investigated using A20 or eEF1A2 gene interference (overexpression and/or silencing). 40 mg/kg of Biliverdin could significantly alleviate CIRI both in vivo and in vitro, promoted the activation of Nrf2, elevated A20 expression, but decreased eEF1A2 expression. Nrf2 can bind to the promoter of A20, thereby transcriptionally regulating the expression of A20. A20 can furthermore interacted with eEF1A2 through its ZnF4 domain to ubiquitinate and degrade it, leading to the downregulation of eEF1A2. Our studies have also demonstrated that either the knock-down of A20 or over-expression of eEF1A2 blunted the protective effect of Biliverdin. Rescue experiments further confirmed that Biliverdin could regulate the NF-κB pathway via the Nrf2/A20/eEF1A2 axis. In summary, our study demonstrates that Biliverdin ameliorates CIRI by inhibiting the NF-κB pathway via the Nrf2/A20/eEF1A2 axis. Our findings can help identify novel therapeutic targets for the treatment of CIRI.

Biliverdin modulates the long non-coding RNA H19/microRNA-181b-5p/endothelial cell specific molecule 1 axis to alleviate cerebral ischemia reperfusion injury.

Injuries caused by cerebral ischemia reperfusion (CIR) can worsen neurological outcomes, Biliverdin (BV) is an antioxidant and anti-apoptotic agent that was shown to affect CIR, although the underlying mechanisms remain unclear. In this study, we investigated the role of BV and its potential underlying mechanism in CIR injury. CIR rat models and primary cortical neurons were established and treated with and without BV. Additionally, adenovirus vectors that could overexpress LncRNA H19 and overexpress or knock-down miR-181b-5p and Esm1 were created to investigate their regulation of molecular expression. Our findings showed that BV could significantly improve CIR injury, both in vivo and in vitro, decrease LncRNA H19 and Esm1 expression, and increase miR-181b-5p expression. Overexpression of LncRNA H19 inhibited the anti-injury effects of BV. Further, the down-regulation of miR-181b-5p or up-regulation of Esm1 expression weakened the in vitro protective effect of BV. RNA immunoprecipitation assay and dual luciferase reporter gene assay further confirmed that LncRNA H19 could sponge miR-181b-5p, and Esm1 was the target of miR-181b-5p. Rescue experiments confirmed that BV could regulate the LncRNA H19/miR-181b-5p/Esm1 molecular axis. Lastly, proteomic and bioinformatic analyzes revealed that Esm1 upregulation in BV-treated neurons resulted in the differential expression of 16 proteins, including 9 upregulated and 7 downregulated proteins. In conclusion, this study found that BV could ameliorate CIR injury by regulating the LncRNA H19/miR-181b-5p/Esm1 axis.

Hierarchical porous activated carbon from waste Zanthoxylum bungeanum branches by modified H3PO4 activation for toluene removal in air.

Activated carbon adsorbents were prepared by chemical activation with waste Zanthoxylum bungeanum branches as raw materials and H3PO4/H2SO4 as composite activator under different dosages of the auxiliary activator H2SO4. The prepared samples were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) specific surface area test, Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The adsorption/desorption performances of low concentration toluene in the air were evaluated, and its reusability was evaluated by the adsorption/desorption cycle. Adsorption results were fitted using the quasi-first, quasi-second, and Bangham models. The adsorption properties of activated carbon adsorbent for toluene in the air show a "volcanic-type change trend" with the increase of H2SO4 dosage. The toluene adsorption properties of the prepared activated carbon adsorbents from high to low are as follows: BAC02 > BAC05 > BAC01 > BAC10 > BAC00. When the mass fraction of auxiliary activator H2SO4 was 2.0%, the adsorption amount of toluene on the prepared BAC02 activated carbon adsorbent increased by 51%, reaching 511 mg/g. After thermal desorption at 200℃, the adsorption performance of toluene was regenerated. The adsorption process of toluene conforms to the quasi-first-order model and Bangham model. The whole adsorption process can be divided into three stages: outer surface adsorption, intra-channel diffusion, and adsorption equilibrium. The addition amount of H2SO4 significantly affected the specific surface area, pore volume, and pore size distribution of the prepared activated carbon adsorbent.

Insight into the effects of oxygen vacancy on the toluene oxidation over α-MnO2 catalyst.

In order to clarify the role of oxygen vacancy (OV), five α-MnO2 catalysts with abundant OVs are fabricated via a novel and facile redox-precipitation approach and employed to the toluene oxidation in air. The concentration of OVs in α-MnO2 catalysts is regulated via the alkyl chain length of alcohols, and its correlation with catalytic performances is scientifically investigated based on various characterization technologies and density functional theory (DFT) calculation. The α-MnO2-C2 catalyst exhibits excellent catalytic activity (T90 = 217 °C), stability, and water resistance for toluene oxidation in air. The OVs can induce the new bandgap states (BGS), which upshift the antibonding orbitals relative to the Fermi level (Ef), eventually favoring the formation of adsorbed active oxygen species. Furthermore, the OVs cause an increase in the amount of Mn3+, resulting in the elongated Mn-O bonds due to the strong Jahn-Teller effect of Mn3+. Therefore, the synergistic effects of OVs benefit toluene oxidation through L-H and MvK mechanisms over the prepared α-MnO2-Cx catalysts. This work reveals the important role of OVs in the promotion of toluene catalytic oxidation activity and also may provide new insights for the design of high-performance VOCs oxidation elimination catalyst.

Virus-inspired surface-nanoengineered antimicrobial liposome: A potential system to simultaneously achieve high activity and selectivity.

Enveloped viruses such as SARS-CoV-2 frequently have a highly infectious nature and are considered effective natural delivery systems exhibiting high efficiency and specificity. Since simultaneously enhancing the activity and selectivity of lipopeptides is a seemingly unsolvable problem for conventional chemistry and pharmaceutical approaches, we present a biomimetic strategy to construct lipopeptide-based mimics of viral architectures and infections to enhance their antimicrobial efficacy while avoiding side effects. Herein, a surface-nanoengineered antimicrobial liposome (SNAL) is developed with the morphological features of enveloped viruses, including a moderate size range, lipid-based membrane structure, and highly lipopeptide-enriched bilayer surface. The SNAL possesses virus-like infection to bacterial cells, which can mediate high-efficiency and high-selectivity bacteria binding, rapidly attack and invade bacteria via plasma membrane fusion pathway, and induce a local "burst" release of lipopeptide to produce irreversible damage of cell membrane. Remarkably, viral mimics are effective against multiple pathogens with low minimum inhibitory concentrations (1.6-6.3 µg mL-1), high bactericidal efficiency of >99% within 2 h, >10-fold enhanced selectivity over free lipopeptide, 99.8% reduction in skin MRSA load after a single treatment, and negligible toxicity. This bioinspired design has significant potential to enhance the therapeutic efficacy of lipopeptides and may create new opportunities for designing next-generation antimicrobials.

Efficient Ni-based catalysts for low-temperature reverse water-gas shift (RWGS) reaction.

CO2 hydrogenation for syngas can alleviate the pressure of un-controlled emissions of CO2 and bring enormous economic benefits. Advantageous Ni-catalysts have good CO2 hydrogenation activity and high CO selectivity merely over 700 °C. Herein, we introduced Cu into Ni catalysts, which were evaluated by H2 -TPR, XRD, BET, in-situ XPS and CO2 -TPD, and their CO2 hydrogenation activity and CO selectivity were significantly affected by the Ni/Cu ratios, which was rationalized by the synergistic effect of bimetallic catalysts. In addition, the reduction temperatures of studied catalysts apparently affected the CO2 hydrogenation, which were caused by the number and dispersion of the active species. It's found that the Ni1 Cu1 -400 had good stability, high CO selectivity (up to 90%), and fast formation rate (1.81×10-5  mol/gcat /s) at 400 °C, which demonstrated a good potential as a superior catalyst for reverse water-gas shift (RWGS) reaction.

Recent advances in the conversion of furfural into bio-chemicals through chemo- and bio-catalysis.

Furfural is a promising renewable platform molecule derived from hemi-cellulose, which can be further converted to fossil fuel alternatives and valuable chemicals due to its highly functionalized molecular structure. This mini-review summarizes the recent progress in the chemo-catalytic and/or bio-catalytic conversion of furfural into high-value-added chemicals, including furfurylamine, C6 carboxylic acid, i.e., furandicarboxylic acid, furfural alcohol, aromatics, levulinic acid, maleic acid, succinic acid, furoic acid, and cyclopentanone, particularly the advances in the catalytic valorization of furfural into useful chemicals in the last few years. The possible reaction mechanisms for the conversion of furfural into bio-chemicals are summarized and discussed. The future prospective and challenges in the utilization of furfural through chemo- and bio-catalysis are also put forward for the further design and optimization of catalytic processes for the conversion of furfural.

A high-efficiency bioinspired photoelectric-electromechanical integrated nanogenerator.

Currently, the key challenge in triboelectric nanogenerators (TENGs) is how to efficiently enhance the surface charge density. Here, a new strategy is proposed to increase the surface charge density by comprehensively utilizing solar energy and tidal energy, and a bioinspired photoelectric-electromechanical integrated TENG (Pem-iTENG) is developed. This enhancement of output performance is greatly attributed to the accumulation of photoelectrons from photocatalysis and the triboelectric negative charges from contact electrification. Pem-iTENG shows a maximal open-circuit voltage of 124.2 V and a maximal short-circuit current density of 221.6 µA cm-2 under tidal wave and sunlight, an improvement by nearly a factor of 10 over that of reported TENGs based on solid-liquid contact electrification. More importantly, it exhibits a high energy conversion efficiency according to the evaluation method for solar cells. This work provides insights into development of high-performance TENGs by using different natural energy sources.

Control of pore structure and surface chemistry of activated carbon derived from waste Zanthoxylum bungeanum branches for toluene removal in air.

Activated carbon adsorption has been considered the most efficient technology toward VOC removal. The waste biomass as alternates solved the problems of high price and nonrenewable of traditional raw materials. The waste Zanthoxylum bungeanum branches were firstly selected as raw materials to prepare activated carbons. Interestingly, the pore structure and surface chemistry can be successfully controlled by adjusting the heating rate. The hierarchical porous carbons exhibited great potential for toluene adsorption. The micro-mesopore structure possessed unique spatial effect; micropores played a dominant role in adsorption process, especially narrow micropores (pore size ≤ 1.0 nm) emerged stronger adsorptive force toward toluene molecules due to overlapping attractive forces from neighboring pore walls. And mesopores not only displayed excellent transport diffusion but also provided adsorption sites. Additionally, the high graphitization degree enhanced the interaction between graphene layer equipped electron-rich regions and π-electrons on the aromatic ring by the π-π conjugated effect. The hydroxyl and carbonyl functional groups served as chemisorption sites and led to higher adsorption amounts. Fortunately, the regeneration can be achieved by thermal treatment at the low temperature (≤ 150 °C) or even gas purging at room temperature (20 °C), which avoided an explosion accident in the process of high-temperature regeneration.

Structural Superiority of Guanidinium-Rich, Four-Armed Copolypeptides: Role of Multiple Peptide-Membrane Interactions in Enhancing Bacterial Membrane Perturbation and Permeability.

The development of novel antimicrobials is a top priority to address the growing epidemic of multidrug-resistant pathogens. Since cationic nonamphiphilic star-shaped antimicrobials are promising molecular scaffolds that provide a high charge density in binding anionic bacterial bilayers, this research aimed to further increase their membrane perturbation capability by introducing guanidinium groups to the antimicrobials via enhancing membrane insertion. In particular, computational simulation and experimental investigations revealed that our designed guanidinium-rich alternating copolypeptide, four-armed poly(arginine-alt-glycine), can interact with both the headgroups and unsaturated tails of phospholipids in bacterial membranes through multiple interactions, including electrostatic, cation-π, and T-shaped π-π interactions, allowing it to penetrate deeper inside the biologically inaccessible high-energy barrier of the hydrophobic lipid bilayer interior to cause membrane permeabilization and precipitation of the bacterial cytoplasm. Furthermore, glycine was observed to have a unique effect in enhancing the performance of arginine-based copolypeptide. Four-armed poly(arginine-alt-glycine) exhibited broad-spectrum antimicrobial activity, high bactericidal efficiency, and negligible hemolysis. The in vivo antibacterial performance of the copolypeptide was superior to that of doxycycline in a mouse model of Pseudomonas aeruginosa skin infection, accompanied by negligible local and systemic toxicity. Our results demonstrate that this guanidinium-rich, nonamphiphilic, star-shaped structure may promote the development of next-generation antimicrobials.

CeCu composite oxide for chlorophenol effective removal by heterogeneous catalytic wet peroxide oxidation.

CeCu solid solution oxide catalysts were prepared by the complex method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS). And its activity in the catalytic wet peroxide oxidation (CWPO) of 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) in water was investigated. The results showed that the Cu2+ ions dissolved into the CeO2 lattice to form CeCu solid solution oxide with a coarse, interconnected, porous, and cotton-like morphology. The metal-oxygen bonds were weakened by the formation of solid solution in the CeCu oxide catalyst. This weakening facilitated the activation and decomposition of the H2O2 to form highly oxidative HO· species that can lead to significant chlorophenol mineralization. The formation of CeCu solid solution oxide can effectively inhibit the Cu ions to be leached from the used CeCu oxide catalysts, which can ensure the CeCu oxide catalysts to adapt to a wide pH range of 2.1-7.9 and exhibit good reusability. CWPO reaction of 4-CP and 2,4-DCP molecules on CeCu oxide catalysts conforms to the first-order kinetic equation: y = 6959.3x - 17.2 and y = 9725x - 25.4, respectively. And the reaction activation energies are 57.8 and 80.8 kJ/mol, respectively. The TOC removals of 4-CP and 2,4-DCP can exceed 88 and 82%, and the dechlorination rates of 4-CP and 2,4-DCP are higher than 95 and 99.5%, respectively.

Tuning the amphiphilicity of terpyridine-based fluorescent probe in water: Assembly and disassembly-controlled H g2+ sensing, removal, and adsorption of H2S.

A water-soluble terpyridine-based cationic fluorescent probe (SP-TPy) was synthesized, which emerged with pH-dependent amphiphilicity, resulting in self-assembly and disassembly in aqueous media with the aggregation-induced emission (AIE) property. In neutral water (pH 7.4), a moderate sensing response to Hg2+ ions was given by the self-assembly of SP-TPy. However, in acidic aqueous media, the monomer of SP-TPy not only appeared to be highly selective and sensitive for Hg2+ ions, but also displayed highly efficient removal of Hg2+ ions from solution by rapid precipitation, which was attributed to the coordination-triggered reassembly of SP-TPy. The removal efficiency of SP-TPy for Hg2+ was found to be over 99%. Further study indicated that the precipitates were composed of various polyhedral porous frameworks, a property that was further used to adsorb H2S gas to form HgS complexes with higher uptake capacities. In addition, SP-TPy can be efficiently regenerated and recycled using a simple treatment with acidic water after adsorption of the H2S gas.

CuO-modified activated carbon for the improvement of toluene removal in air.

We used an impregnation method to prepare CuO/AC (activated carbon) composite materials of different CuO content and characterized them via scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), and Fourier transform infrared spectroscopy (FT-IR). The effect of CuO content on toluene adsorption/desorption was evaluated. We explored the reusability of AC and AC03 (CuO modified AC with CuO loading 0.3 wt.%) adsorbents via toluene adsorption/desorption cycle testing. We used quasi-first- and quasi-second-order models, the Bangham model, and the Weber-Morris model to fit the toluene adsorption data. The introduction of CuO species evidently improved the adsorption performance of activated carbon toward toluene. The CuO content markedly affected the specific surface area, CuO dispersal, the numbers of oxygen-containing functional groups on the surface, and adsorption performance of the prepared composite adsorbents. Low CuO content was not favorable for the formation of active adsorption sites, while high content greatly reduced the specific surface area, and even covered active adsorption sites. The toluene adsorption performance varied in the order AC03 > AC02 > AC05 > AC08 > AC01 (AC03, AC02, AC05, AC08 and AC01 are CuO modifying AC with CuO loading 0.3, 0.2, 0.5 0.8 and 0.1 wt.%, respectively). The breakthrough time and toluene adsorption capacity of the AC03 composite adsorbent were 94 min and 701.8 mg/g, respectively, and the recycling efficiency was 92.8% after thermal desorption at 200°C. The adsorption process was best described by the Bangham model and adsorption could be divided into three stages.

Degradation of Bisphenol A by CeCu Oxide Catalyst in Catalytic Wet Peroxide Oxidation: Efficiency, Stability, and Mechanism.

The CeCu oxide catalyst CC450 was prepared by citric acid complex method and the catalytic wet peroxide oxidation (CWPO) reaction system was established with bisphenol A (BPA) as the target pollutant. By means of characterization, this research investigated the phase structure, surface morphology, reducibility, surface element composition, and valence of the catalyst before and after reuse. The effects of catalyst dosage and pH on the removal efficiency of BPA were also investigated. Five reuse experiments were carried out to investigate the reusability of the catalyst. In addition, this research delved into the changes of pH value, hydroxyl radical concentration, and ultraviolet-visible spectra of BPA in CWPO reaction system. The possible intermediate products were analyzed by gas chromatography-mass spectrometry (GC-MS). The catalytic mechanism and degradation pathway were also discussed. The results showed that after reaction of 65 min, the removal of BPA and total organic carbon (TOC) could reach 87.6% and 77.9%, respectively. The catalyst showed strong pH adaptability and had high removal efficiency of BPA in the range of pH 1.6-7.9. After five reuses, the removal of BPA remained above 86.7%, with the structure of the catalyst remaining stable to a large extent. With the reaction proceeding, the pH value of the reaction solution increased, the concentration of OH radicals decreased, and the ultraviolet-visible spectrum of BPA shifted to the short wavelength direction, that is, the blue shift direction. The catalysts degraded BPA rapidly in CWPO reaction system and the C-C bond or O-H bond in BPA could be destroyed in a very short time. Also, there may have been two main degradation paths of phenol and ketone.

Involvement of an alternative oxidase in the regulation of hyphal growth and microsclerotial formation in Nomuraea rileyi CQNr01.

Mitochondria of Nomuraea rileyi contain an alternative oxidase (Aox), which reduces oxygen to water by accepting electrons directly from ubiquinol. Furthermore, through a transcriptional analysis, we found that an alternative oxidase (Nraox) was up-regulated during microsclerotial formation. To study the function of NrAox, Nraox was cloned from N. rileyi CQNr01. The full-length cDNA was 1266 bp with an open reading frame of 1068 bp encoding 355 amino acids. A phylogenetic analysis revealed that the NrAox of N. rileyi was closely related to Metarhizium acridum Aox. The relative expression level of the Nraox was up-regulated during microsclerotial (MS) initiation. A salicylhydroxamic acid, a specific alternative oxidase inhibitor, application to the culture media severely decreased MS yields, changed the hyphae morphology and slowed the H2O2 removal. Nraox silencing caused mycelial deformations, reduced the MS yields by 97.3 % and increased MS size compared with those of the control. MS virulence was decreased to 26.2 % after Nraox was silenced. However, the Nraox-silenced strain was sensitive to environmental stress, and the growth rate was reduced under stress conditions. The results obtained suggested that Nraox is required for MS differentiation by regulating the intracellular H2O2 concentration and hypha growth. Additionally, Nraox had a great impact on the virulence of N. rileyi.

RacA and Cdc42 regulate polarized growth and microsclerotium formation in the dimorphic fungus Nomuraea rileyi.

Small GTPases, RacA and Cdc42, act as molecular switches in fungi, regulating cell signaling, cytoskeletal organization, polar growth and reactive oxygen species (ROS) generation, the latter by influencing the activity of the NADPH oxidase complex. In this study, the racA and cdc42 genes from Nomuraea rileyi were cloned and shown to encode 218 and 184 amino acid proteins, respectively. To determine the functions of racA and cdc42, gene-silencing mutants (racARM, cdc42RM and racA&cdc42RM, respectively) were generated using RNA silencing technology. In racARM and cdc42RM, the conidial and microsclerotium (MS) yields, ROS production and virulence were reduced, the hyphal extension rate was decreased and the dimorphic switch was delayed. On the other hand, the double-silencing mutants showed growth retardation and virtually no conidia, MS or ROS production. The transcription levels of the noxA and noxR genes that regulate ROS generation were reduced in the three RNAi-silenced strains. Interestingly, when compared with the controls, racARM exhibited thicker hyphae and bigger conidia; moreover, the MS produced by racARM were bigger than those of the control and smaller than those of cdc42RM. Thus RacA and Cdc42 appear to share some essential functions in N. rileyi, including hyphal growth, conidiation, MS formation, ROS generation and virulence. Yet RacA appears to play a more pivotal role in the polar growth of N. rileyi.

Fine mapping a major QTL for flag leaf size and yield-related traits in rice.

Leaf size is a major determinant of plant architecture and yield potential in crops. A previous study showed that the genomic region of chromosome 1 contains a major quantitative trait locus (QTL) for flag leaf size in a set of backcross recombinant inbred lines derived from two elite parental lines (Zhenshan 97 and 93-11). In the present study, the QTL (qFL1) was shown to explain a large proportion of the variation in flag leaf size (leaf length, width and area) in derived populations (BC(2)F(3) and BC(3)F(2)) in multiple environments. Using a large segregating population, we narrowed the location of qFL1 to a 31 kb region containing four predicted genes. Expression of one of these genes, OsFTL1, differed between leaves in near-isogenic lines carrying alleles of Zhenshan 97 and 93-11. qFL1 had a pleiotropic effect on flag leaf size and yield-related traits. Conditional QTL analysis of the derived population (BC(3)F(2)) supports the assertion that qFL1 is the QTL for flag leaf length and exhibits pleiotropy. Pyramiding of qFL1 with two known genes (GS3 and Wx) from 93-11 into Zhenshan 97 enlarged flag leaves, improved grain size and amylose content, and increased yield per plant, but slightly delayed heading date. These results provide a foundation for the functional characterization of the gene underlying the pleiotropic effects of qFL1 and for genetic improvement of the plant architecture and yield potential of rice.