No abstract

Foliar NH4(+) exposure is linked to inhibition of lateral root (LR) formation. Here, the role of shoot ethylene in NH4(+)-induced inhibition of LR formation in Arabidopsis was investigated using wild-type and mutant lines that show either blocked ethylene signalling (etr1) or enhanced ethylene synthesis (eto1, xbat32). NH4(+) exposure of wild-type Arabidopsis led to pronounced inhibition of LR production chiefly in the distal root, and triggered ethylene evolution and enhanced activity of the ethylene reporter EBS:GUS in the shoot. It is shown that shoot contact with NH4(+) is necessary to stimulate shoot ethylene evolution. The ethylene antagonists Ag(+) and aminoethoxyvinylglycine (AVG) mitigated LR inhibition under NH4(+) treatment. The decrease in LR production was significantly greater for eto1-1 and xbat32 and significantly less for etr1-3. Enhanced shoot ethylene synthesis/signalling blocked recovery of LR production when auxin was applied in the presence of NH4(+) and negatively impacted shoot AUX1 expression. The findings highlight the important role of shoot ethylene evolution in NH4(+)-mediated inhibition of LR formation.

Increasing consumer concern in greenhouse-gas (GHG) contributions from cattle is pushing the livestock industry to continue to improve their sustainability goals. As populations increase, particularly in low-income countries, the demand for animal-sourced foods will place further pressure to reduce emission intensity. Enteric methane (CH 4 ) production contributes to most of the GHG from livestock; therefore, it is key to mitigating such emissions. Feed additives have primarily been used to increase animal productivity, but advances in understanding the rumen has resulted in their development to mitigate CH 4 emissions. The present study reviewed some of the main feed additives with a potential to reduce enteric CH 4 emissions, focusing on in vivo studies. Feed additives work by either inhibiting methanogenesis or modifying the rumen environment, such that CH 4 production (g/day) is reduced. Feed additives that inhibit methanogenesis or compete with substrate for methanogens include 3-nitroxypropanol (3NOP), nitrates, and halogenated compounds containing organisms such as macroalgae. Although 3NOP and macroalgae affect methyl-coenzyme M reductase enzyme that is necessary in CH 4 biosynthesis, the former is more specific to methanogens. In contrast, nitrates reduce CH 4 emissions by competing with methanogens for hydrogen. However, nitrite could accumulate in blood and be toxic to ruminants. Rumen modifiers do not act directly on methanogens but rather on the conditions that promote methanogenesis. These feed additives include lipids, plant secondary compounds and essential oils. The efficacy of lipids has been studied extensively, and although supplementation with mediumchain and polyunsaturated fatty acids has shown substantial reduction in enteric CH 4 production, the results have been variable. Similarly, secondary plant compounds and essential oils have shown inconsistent results, ranging from substantial reduction to modest increase in enteric CH 4 emissions. Due to continued interest in this area, research is expected to accelerate in developing feed additives that can provide options in mitigating enteric CH 4 emissions.

No abstract

Marine-derived fungi are prone to produce structurally unique secondary metabolites, a considerable number of which display the promising biological properties and/or industrial applications. Among those, ligninolytic enzymes have attracted great interest in recent years. In this work, about 20 strains were isolated from sea mud samples collected in the East China Sea and then screened for their capacity to produce lignin-degrading enzymes. The results showed that a strain, named J63, had a great potential to secrete a considerable amount of laccase. Using molecular method, it was identified as an endophytic fungus, Pestalotiopsis sp. which was rarely reported as ligninolytic enzyme producer in the literature. The production of laccase by Pestalotiopsis sp. J63 was investigated under submerged fermentation (SF) and solid state fermentation (SSF) with various lignocellulosic by-products as substrates. The SSF of rice straw powder accumulated the highest level of laccase activity (10,700 IU/g substrate), whereas the SF of untreated sugarcane bagasse provided the maximum amount of laccase activity (2,000 IU/ml). The value was far higher than those reported by other reports. In addition, it produced 0.11 U/ml cellulase when alkaline-pretreated sugarcane bagasse was used as growth substrate under SF. Meanwhile, the growth of fungi and laccase production under different salinity conditions were also studied. It appeared to be a moderately halo-tolerant organism.

Lithium (Li) metal is one of the promising anode materials in the next-generation high-energy batteries, but Li dendrite growth and a big volume change during cycling result in low Coulombic efficiency (CE), short lifespan, and safety hazards, thereby impeding practical implementation of Li in rechargeable batteries. Herein, we report a highly stable and dendrite-free Li metal anode based on a three-dimensional (3D) conductive and lithiophilic scaffold comprising lithiated NiCo2O4 nanorods grown on nickel foam (LNCO/Ni). The nanorods grown on 3D Ni foam with a large surface area effectively reduce the averaged electrical current in the electrode, and the conformal Li2O coating produced in situ on the lithiated NiCo2O4 nanorods provides the surface lithiophilicity enabling stable Li plating/stripping without Li dendrite growth even at a high current density of 5 mA cm–2. The LNCO/Ni–Li anode shows a low voltage hysteresis of 16 mV, high CE of 98.7%, and stable cycling without obvious voltage fluctuation for over 500 cycles (1000 h) at a current density of 1 mA cm–2. Specifically, for a scalable Li loading of 20 mA h cm–2 on LNCO/Ni, no growth of Li dendrite and electrode thickness fluctuations are observed. The full cell consisting of the LNCO/Ni–Li anode and the LiFePO4 cathode exhibits a high rate capability and CE as high as 99.6% for more than 160 cycles. Our study reveals a new strategy to develop stable Li-metal anodes for high-energy batteries.

Out-of-plane spin polarization σz has attracted increasing interests of researchers recently, due to its potential in high-density and low-power spintronic devices. Noncollinear antiferromagnet (AFM), which has unique 120° triangular spin configuration, has been discovered to possess σz. However, the physical origin of σz in noncollinear AFM is still not clear, and the external magnetic field-free switching of perpendicular magnetic layer using the corresponding σz has not been reported yet. Here, we use the cluster magnetic octupole in antiperovskite AFM Mn3SnN to demonstrate the generation of σz. σz is induced by the precession of carrier spins when currents flow through the cluster magnetic octupole, which also relies on the direction of the cluster magnetic octupole in conjunction with the applied current. With the aid of σz, current induced spin-orbit torque (SOT) switching of adjacent perpendicular ferromagnet is realized without external magnetic field. Our findings present a new perspective to the generation of out-of-plane spin polarizations via noncollinear AFM spin structure, and provide a potential path to realize ultrafast high-density applications.

Interface structure plays an extremely important role in the charge-transfer and photocatalytic performances in plasmonic metal/semiconductor systems. Defect engineering by introducing an oxygen vacancy (Ovac) is an effective way to modulate the interface structure. Here, a representative photocatalyst system including TiO2, TiO2–x , Au-TiO2 and Au-TiO2–x as designed delicately to reveal the detailed mechanism of the plasmon-resonance-induced charge separation in interfacial defect structure from the nanoscale. The local charge transfer via a conducting amorphous-like interface layer is visualized as the arched valence change from Ti3+ to Ti4+ at the Au-TiO2–x interface after Schottky contact. This phenomenon eventually leads to the enhancement of localized surface plasmon resonance (LSPR) at 2.3 eV, and the introduction of Ovac reduces the Schottky barrier height of Au-TiO2–x by 5 mV compared with that of Au-TiO2. Under visible light, Au-TiO2–x excites the most photogenerated carriers to the surface, which is larger than that of TiO2–x and Au-TiO2. It can be concluded that the changes in electronic structure eventually promote charge transfer in visible light and explain the original reason that the coupling of Ovac and Au could improve the photocatalytic performance.