This work reports that natural graphite is capable of Na insertion and extraction with a remarkable reversibility using ether-based electrolytes. Natural graphite (the most well-known anode material for Li-ion batteries) has been barely studied as a suitable anode for Na rechargeable batteries due to the lack of Na intercalation capability. Herein, graphite is not only capable of Na intercalation but also exhibits outstanding performance as an anode for Na ion batteries. The graphite anode delivers a reversible capacity of ≈150 mAh g −1 with a cycle stability for 2500 cycles, and more than 75 mAh g −1 at 10 A g −1 despite its micrometer-size (≈100 µm). An Na storage mechanism in graphite, where Na + -solvent co-intercalation occurs combined with partial pseudocapacitive behaviors, is revealed in detail. It is demonstrated that the electrolyte solvent species signifi cantly affect the electrochemical properties, not only rate capability but also redox potential. The feasibility of graphite in a Na full cell is also confi rmed in conjunction with the Na 1.5 VPO 4.8 F 0.7 cathode, delivering an energy of ≈120 Wh kg −1 while maintaining ≈70% of the initial capacity after 250 cycles. This exceptional behavior of natural graphite promises new avenues for the development of cost-effective and reliable Na ion batteries.

Methyl jasmonate is a plant volatile that acts as an important cellular regulator mediating diverse developmental processes and defense responses. We have cloned the novel gene JMT encoding an S-adenosyl-L-methionine:jasmonic acid carboxyl methyltransferase (JMT) from Arabidopsis thaliana. Recombinant JMT protein expressed in Escherichia coli catalyzed the formation of methyl jasmonate from jasmonic acid with K m value of 38.5 M. JMT RNA was not detected in young seedlings but was detected in rosettes, cauline leaves, and developing flowers. In addition, expression of the gene was induced both locally and systemically by wounding or methyl jasmonate treatment. This result suggests that JMT can perceive and respond to local and systemic signals generated by external stimuli, and that the signals may include methyl jasmonate itself. Transgenic Arabidopsis overexpressing JMT had a 3-fold elevated level of endogenous methyl jasmonate without altering jasmonic acid content. The transgenic plants exhibited constitutive expression of jasmonate-responsive genes, including VSP and PDF1.2. Furthermore, the transgenic plants showed enhanced level of resistance against the virulent fungus Botrytis cinerea. Thus, our data suggest that the jasmonic acid carboxyl methyltransferase is a key enzyme for jasmonate-regulated plant responses. Activation of JMT expression leads to production of methyl jasmonate that could act as an intracellular regulator, a diffusible intercellular signal transducer, and an airborne signal mediating intra-and interplant communications.

SummaryBurkholderia glumae BGR1 produces a broad-host range phytotoxin, called toxoflavin, which is a key pathogenicity factor in rice grain rot and wilt in many field crops. Our molecular and genetic analyses of toxoflavin-deficient mutants demonstrated that gene clusters for toxoflavin production consist of four transcriptional units. The toxoflavin biosynthesis genes were composed of five genes, toxA to toxE , as Suzuki et al. (2004) reported previously. Genes toxF to toxI , which are responsible for toxoflavin transport, were polycistronic and similar to the genes for resistancenodulation-division (RND) efflux systems. Using Tn 3 -gusA reporter fusions, we found that ToxR, a LysRtype regulator, regulates both the toxABCDE and toxFGHI operons in the presence of toxoflavin as a coinducer. In addition, the expression of both operons required a transcriptional activator, ToxJ, whose expression is regulated by quorum sensing. TofI, a LuxI homologue, was responsible for the biosynthesis of both N -hexanoyl homoserine lactone and Noctanoyl homoserine lactone (C8-HSL). C8-HSL and its cognate receptor TofR, a LuxR homologue, activated toxJ expression. This is the first report that quorum sensing is involved in pathogenicity by the regulation of phytotoxin biosynthesis and its transport in plant pathogenic bacteria.

Voltage decay and redox asymmetry mitigation by reversible cation migration in lithiumrich layered oxide electrodes.