A novel route for identifying starch diagenetic products in the archaeological record.

This work introduces a novel analytical chemistry method potentially applicable to the study of archaeological starch residues. The investigation involved the laboratory synthesis of model Maillard reaction mixtures and their analysis through Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS). Thus, starch from sixteen plant species were matured while reacting it with the amino acid glycine. The FTICR-MS analysis revealed > 5,300 molecular compounds, with numerous unique heteroatom rich compound classes, ranging from 20 (Zea mays) to 50 (Sorghum bicolor). These classes were investigated as repositories of chemical structure retaining source and process-specific character, linked back to botanical provenance. We discussed the Maillard reaction products thus generated, a possible pathway for the preservation of degraded starch, while also assessing diagenetic recalcitrance and adsorption potential to mineral surfaces. In some cases, hydrothermal experimentation on starches without glycine reveals that the chemical complexity of the starch itself is sufficient to produce some Maillard reaction products. The article concludes that FTICR-MS offers a new analytical window to characterize starchy residue and its diagenetic products, and is able to recognize taxonomic signals with the potential to persist in fossil contexts.

A rapid method to assess a broad inventory of organic species in marine sediments using ultra-high resolution mass spectrometry.

RATIONALE: A broad range of organic species in marine sediments is routinely used as biogeochemical proxies of Earth history. These species are typically analyzed using different analytical methods, targeting very specific components and often including time-intensive sample preparation. There is, therefore, a need for a more comprehensive, rapid and high-throughput approach to simultaneously analyze a broad range of known sedimentary polar species and also have a surveillance capability able to identify candidate new species classes. METHODS: Whole solvent extracts from recently deposited Gulf of Mexico marine sediments were obtained after a simple, one-step extraction. They were analyzed by Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), using atmospheric pressure photoionization in positive ion mode (APPI-P), over a broad mass range (m/z 150-1500). RESULTS: From 3000 to over 5000 peaks per sample were assigned molecular formulae, and the majority of assignments (90%) showed an absolute error lower than 200 ppb. The detected species belong to the NO1-7 , N4 O2-8 , O1-9 , HC, N and OS compound classes, including known biomarker species such as pigments (e.g. tetrapyrrole macrocycles and carotenoids) and lipids (e.g. glycerol dialkyl glycerol tetraethers, GDGTs), but also compounds of still unknown detailed molecular structure, but with clear potential geochemical relevance. CONCLUSIONS: The reported method enables rapid (12 min FTICR-MS analysis time) and simultaneous detection of a broad range of multi-heteroatom, polar organic species in whole sediment extracts. This allows for higher sample throughput, a more comprehensive investigation of sedimentary geochemistry, and potentially the discovery of new components and derivation of novel, multi-species proxies. Copyright © 2016 John Wiley & Sons, Ltd.

Chronic morpho-functional damage as a consequence of transient ischemia/reperfusion injury of the small bowel.

INTRODUCTION: The prevailing notion is that ischemia reperfusion injury of the small bowel induces transient changes that resolve within a few days post-occurrence. However, chronic injury has been described following a single ischemia reperfusion in the kidney. We proceeded to ascertain if a similar outcome is also witnessed in the small bowel. MATERIALS AND METHODS: ACI rats (n=32) underwent 1, 2 or 3 episodes of ischemia reperfusion by clamping the superior mesenteric artery for 45 minutes at 7-day intervals. Control groups included sham-operated (n=6) or non-operated (n=5) rats. Morphology was examined at day ninety post-ischemia reperfusion and immunostaining was used to evaluate macrophage infiltration, microvascular distribution, and apoptosis. RT-PCR was used to evaluate expression of Inter-Cellular Adhesion Molecule-1 (ICAM-1), transforming growth factor-beta (TGF-beta), Insulin Growth Factor-I (IGF-1), and Insulin Growth Factor-I Receptor (IGF-R). Intestinal function was evaluated by D-xylose performed 24 hours and 4, 8, and 12 weeks after reperfusion. RESULTS: Chronic morphologic changes were observed with degeneration of crypts, endothelial damage, matrix degeneration, and heightened lymphocyte degeneration within the Payer's patches. Major structural changes were characterized by villous atrophy from partial to total. The grade of histological injuries was significantly increased (P<0.001) after multiple ischemia reperfusion episodes. A higher number of apoptotic cells (P<0.001) and a prominent macrophage infiltration (P<0.05) was also witnessed. Altered expression of ICAM-1, TGF-beta, and IGF-1 was observed. At 24 hours after ischemia reperfusion D-xylose absorption was diminished, returning to baseline values within 4 weeks and becoming abnormal again at 8 and 12 weeks (P<0.05). CONCLUSIONS: Unlike the prevailing conviction, these data demonstrate that transient ischemia reperfusion repeated injuries of the small bowel result in chronic intestinal damage.