A new kind of nitrogen-rich fluorescent conjugated microporous polymer TTPB was synthesized via a Friedel–Crafts reaction of 2,4,6-trichloro-1,3,5-triazine and N,N,N′,N′-tetraphenylbenzidine catalyzed by methanesulfonic acid.

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Summary Salicylic acid (SA) plays a critical role in plant defense against pathogen invasion. SA‐induced viral defense in plants is distinct from the pathways mediating bacterial and fungal defense and involves a specific pathway mediated by mitochondria; however, the underlying mechanisms remain largely unknown. The SA‐binding activity of the recombinant tomato (Solanum lycopersicum) alpha‐ketoglutarate dehydrogenase (Slα‐kGDH) E2 subunit of the tricarboxylic acid (TCA) cycle was characterized. The biological role of this binding in plant defenses against tobacco mosaic virus (TMV) was further investigated via Slα‐kGDH E2 silencing and transient overexpression in plants. Slα‐kGDH E2 was found to bind SA in two independent assays. SA treatment, as well as Slα‐kGDH E2 silencing, increased resistance to TMV. SA did not further enhance TMV defense in Slα‐kGDH E2‐silenced tomato plants but did reduce TMV susceptibility in Nicotiana benthamiana plants transiently overexpressing Slα‐kGDH E2. Furthermore, Slα‐kGDH E2‐silencing‐induced TMV resistance was fully blocked by bongkrekic acid application and alternative oxidase 1a silencing. These results indicated that binding by Slα‐kGDH E2 of SA acts upstream of and affects the mitochondrial electron transport chain, which plays an important role in basal defense against TMV. The findings of this study help to elucidate the mechanisms of SA‐induced viral defense.

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Abstract. We studied sediments from the ca. 1400 millionyear-old Xiamaling Formation from the North China block. The upper unit of this formation (unit 1) deposited mostly below storm wave base and contains alternating black and green-gray shales with very distinct geochemical characteristics. The black shales are enriched in redox-sensitive trace metals, have high concentrations of total organic carbon (TOC), high hydrogen index (HI) and iron speciation indicating deposition under anoxic conditions. In contrast, the green-gray shales show no trace metal enrichments, have low TOC, low HI and iron speciation consistent with an oxygenated depositional setting. Altogether, unit 1 displays alternations between oxic and anoxic depositional environments, driving differences in carbon preservation consistent with observations from the modern ocean. We combined our TOC and HI results to calculate the differences in carbon mineralization and carbon preservation by comparing the oxygenated and anoxic depositional environments. Through comparisons of these results with modern sedimentary environments, and by use of a simple diagenetic model, we conclude that the enhanced carbon mineralization under oxygenated conditions in unit 1 of the Xiamaling Formation required a minimum of 4 to 8 % of present-day atmospheric levels (PAL) of oxygen. These oxygen levels are higher than estimates based on chromium isotopes and reinforce the idea that the environment contained enough oxygen for animals long before their evolution.

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