High Reversibility of Lattice Oxygen Redox in Na-ion and Li-ion Batteries Quantified by Direct Bulk Probes of both Anionic and Cationic Redox Reactions

The reversibility and cyclability of anionic redox in battery electrodes hold the key to its practical employments. Here, through mapping of resonant inelastic X-ray scattering (mRIXS), we have independently quantified the evolving redox states of both cations and anions in Na2/3Mg1/3Mn2/3O2. The bulk-Mn redox emerges from initial discharge and is quantified by inverse-partial fluorescence yield (iPFY) from Mn-L mRIXS. Bulk and surface Mn activities likely lead to the voltage fade. O-K super-partial fluorescence yield (sPFY) analysis of mRIXS shows 79% lattice oxygen-redox reversibility during initial cycle, with 87% capacity sustained after 100 cycles. In Li1.17Ni0.21Co0.08Mn0.54O2, lattice-oxygen redox is 76% initial-cycle reversible but with only 44% capacity retention after 500 cycles. These results unambiguously show the high reversibility of lattice-oxygen redox in both Li-ion and Na-ion systems. The contrast between Na2/3Mg1/3Mn2/3O2 and Li1.17Ni0.21Co0.08Mn0.54O2 systems suggests the importance of distinguishing lattice-oxygen redox from other oxygen activities for clarifying its intrinsic properties.Comment: 33 pages, 8 Figures. Plus 14 pages of Supplementary Materials with 12 Figure

Bacterial microbiota protect an invasive bark beetle from a pine defensive compound

Abstract Background There is growing evidence that some devastating biotic invasions are facilitated by microbial symbionts. The red turpentine beetle (RTB), an innocuous secondary insect attacking weakened trees in North America, has formed an invasive complex with the fungus Leptographium procerum in China, and this invasive beetle-fungus symbiotic complex is capable of attacking and killing healthy pines. A previous study demonstrated that three Chinese-resident fungi, newly acquired by RTB in China, induce high levels of a phenolic defensive chemical, naringenin, in pines and this invasive beetle-fungus complex is suppressed by elevated levels of naringenin while the beetle uses its gallery as an external detoxification system in which particular yeast-like fungi and bacterial species biodegrade naringenin. However, the functional roles of key microbial players in the symbiosis, contained within the microbiome of the bark beetle gallery, have not been well elucidated. Results In this report, the symbiotic naringenin-degrading microbiota were found to increase RTB survivorship in the presence of induced host defenses, and potential genes associated with degradation pathways were discovered. While fungi in the gallery microbiota had little involvement in naringenin degradation, bacterial community structure within the beetle gallery was highly correlated to naringenin degrading activity. Phylotypes of the Gram-negative bacterial genus Novosphingobium, which possessed genes involved in degradation pathways, were highly correlated to naringenin degradation activities and RTB associated with an isolated species of this genus acquired protection against naringenin and gained fitness. Conclusions Our results demonstrated that symbiotic bacterial community of RTB galleries enhances the survivorship and overall fitness of invasive beetles by degrading the host phenolic naringenin, ultimately overcoming the tree defenses and facilitating the success of the invasive beetle-fungi complex. This dynamic interplay between the invasive insect pest and multipartite microbes suggests a putative mechanism in invasion ecology for mitigating biotic resistance to symbiotic invasion

Additional file 3: of Bacterial microbiota protect an invasive bark beetle from a pine defensive compound

Gene IDs of KEGG pathways in map01120. (HTML 848 kb

Additional file 2: of Bacterial microbiota protect an invasive bark beetle from a pine defensive compound

map01120. Projection of genes involved in microbial metabolism in diverse environments on the KEGG pathways. (PNG 276 kb

Additional file 1: of Bacterial microbiota protect an invasive bark beetle from a pine defensive compound

This file includes: Table S1. eggNOG function annotation for dioxygenases in aromatics degradation. Table S2. Comparison of diversity indices (Mean ± SEM) between bacterial gallery microbiota of low (L), medium (M), and high (H) naringenin biodegrading activity. Table S3. Comparison of diversity indices (Mean ± SEM) between fungal gallery microbiota of low (L), medium (M), and high (H) naringenin biodegrading activity. Table S4. Class- and order-level comparisons between fungal communities in RTB galleries of low (L), medium (M), and high (H) naringenin degrading activity. Table S5. Changes in relative abundances of main bacterial genera with reported known functions in biodegradation. Table S6. ANOSIM R values between naringenin biodegrading activity groups. Table S7. Model statistics of PLS. Table S8. Detailed information for the 86 indicator phylotypes. Figure S1. Naringenin-biodegrading activity (Mean ± SEM) of RTB galleries with large variation between samples. Figure S2. Rarefaction curves of the 19 samples for bacterial OTUs and fungal OTUs. Figure S3. Effects of anti-fungal and anti-bacterial treatments on naringenin degradation, under liquid and solid media condition. Figure S4. The rank abundance diagram of the 708 bacterial OTUs and 209 fungal OTUs identified, plotted as the traditional Whittaker plot. Figure S5. Effects of anti-bacterial treatments on naringenin degradation and abundance of Gram-negative bacteria. Figure S6. KEGG pathway annotations for Gram-negative bacteria and Gram-positive bacteria in RTB gallery microbiota. (DOC 5448 kb