Ginkgo biloba is one of the oldest extant seed plants and has a number of unique properties and uses. Numerous efforts have characterized metabolites within the ginkgo plant and their corresponding biosynthesis pathways, but spatio-chemical information on ginkgo metabolites is lacking. Mass spectrometry (MS) imaging was used to interrogate the spatio-chemical localization of metabolites with matrix-assisted laser desorption/ionization and laser desorption/ionization Fourier-transform ion cyclotron resonance MS across the ginkgo leaf. Flavonoids, particularly unexpected and rare flavonoid cyclodimers, were detected predominately from leaf epidermis; ginkgolic acids and cardanols were observed exclusively in the secretory cavities. A non-uniform distribution of flavonoids observed between the upper and lower leaf epidermis was verified by liquid chromatography-MS analyses. Other metabolites, such as saccharides, phospholipids, and chlorophylls, occurred mainly in mesophyll cells. Furthermore, organ- and tissue-specific distributions of ginkgolides were revealed in the ginkgo root, young stem, and leaf. The acquired ion images provide important information regarding biosynthesis, transportation, and accumulation of metabolites throughout the ginkgo plant and should help us to understand the physiological roles of several plant secondary metabolites.

Imaging mass spectrometry (IMS) technologies are capable of mapping a wide array of biomolecules in diverse cellular and tissue environments. IMS has emerged as an essential tool for providing spatially targeted molecular information due to its high sensitivity, wide molecular coverage, and chemical specificity. One of the major challenges for mapping the complex cellular milieu is the presence of many isomers and isobars in these samples. This challenge is traditionally addressed using orthogonal liquid chromatography (LC)-based analysis, though, common approaches such as chromatography and electrophoresis are not able to be performed at timescales that are compatible with most imaging applications. Ion mobility offers rapid, gas-phase separations that are readily integrated with IMS workflows in order to provide additional data dimensionality that can improve signal-to-noise, dynamic range, and specificity. Here, we highlight recent examples of ion mobility coupled to IMS and highlight their importance to the field.

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We leveraged the recent increase in synthetic accessibility of SF 5 Cl and ArÀ SF 4 Cl compounds to combine chemistry of the SF 5 and SF 4 Ar groups with strain-release functionalization. By effectively adding SF 5 and SF 4 Ar radicals across [1.1.1]propellane, we accessed structurally unique bicyclopentanes, bearing two distinct elements of bioisosterism. Upon evaluating these "hybrid isostere" motifs in the solid state, we measured exceptionally short transannular distances; in one case, the distance rivals the shortest nonbonding C•••C contact reported to date. This prompted SC-XRD and DFT analyses that support the notion that a donoracceptor interaction involving the "wing" CÀ C bonds is playing an important role in stabilization. Thus, these heretofore unknown structures expand the palette for highly coveted three-dimensional fluorinated building blocks and provide insight to a more general effect observed in bicyclopentanes.

Summary Here, we describe the preservation and preparation of human kidney tissue for interrogation by histopathology, imaging mass spectrometry, and multiplexed immunofluorescence. Custom image registration and integration techniques are used to create cellular and molecular atlases of this organ system. Through careful optimization, we ensure high-quality and reproducible datasets suitable for cross-patient comparisons that are essential to understanding human health and disease. Moreover, each of these steps can be adapted to other organ systems or diseases, enabling additional atlas efforts.