Disentangling thermal stress responses in a reef-calcifier and its photosymbionts by shotgun proteomics

This project was funded by the Leibniz Association (SAW-2014-ISAS-2) awarded to AS and HW and supported by the Ministerium für Kultur und Wissenschaft des Landes Nordrhein-Westfalen, the Regierende Bürgermeister von Berlin - inkl. Wissenschaft und Forschung, and the Bundesministerium für Bildung und Forschung. Sampling was conducted under the Research Permit No. FKNMS-2015–026, issued to Pamela Hallock who is warmly acknowledged for her general support and assistance during fieldwork.Peer reviewedPublisher PD

Cutting the Gordian knot : early and complete amino acid sequence confirmation of class II lasso peptides by HCD fragmentation

SAJ would like to thank the University of Aberdeen for an Elphinstone Scholarship. CC-A thanks CONICYT PFCHA/DOCTORADO BECAS CHILE/2016 (#21160585) fellowship and CONICYT Basal Centre Grant for the Centre for Biotechnology and Bioengineering, CeBiB (FB0001). JFC also thanks CONICYT for a National PhD Scholarship (#21110356) and a Visiting Student Scholarship.Peer reviewedPostprin

Short Peptides with Uncleavable Peptide Bond Mimetics as Photoactivatable Caspase-3 Inhibitors

Chemical probes that covalently interact with proteases have found increasing use for the study of protease function and localization. The design and synthesis of such probes is still a bottleneck, as the strategies to target different families are highly diverse. We set out to design and synthesize chemical probes based on protease substrate specificity with inclusion of an uncleavable peptide bond mimic and a photocrosslinker for covalent modification of the protease target. With caspase-3 as a model target protease, we designed reduced amide and triazolo peptides as substrate mimetics, whose sequences can be conveniently constructed by modified solid phase peptide synthesis. We found that these probes inhibited the caspase-3 activity, but did not form a covalent bond. It turned out that the reduced amide mimics, upon irradiation with a benzophenone as photosensitizer, are oxidized and form low concentrations of peptide aldehydes, which then act as inhibitors of caspase-3. This type of photoactivation may be utilized in future photopharmacology experiments to form protease inhibitors at a precise time and location.status: publishe

Proteome data of Amphistegina gibbosa

The proliferation of key marine ecological engineers and carbonate producers often relies on their association with photosymbiotic algae. Evaluating stress responses of these organisms is important to predict their fate under future climate projections. Physiological approaches are limited in their ability to resolve the involved molecular mechanisms and attribute stress effects to the host or symbiont, while probing and partitioning of proteins cannot be applied in organisms where the host and symbiont are small and cannot be physically separated. Here we apply a label-free quantitative proteomics approach to detect changes of proteome composition in the diatom-bearing benthic foraminifera Amphistegina gibbosa experimentally exposed to three thermal-stress scenarios. We developed a workflow for protein extraction from less than ten specimens and simultaneously analysed host and symbiont proteomes. Despite little genomic data for the host, 1,618 proteins could be partially assembled and assigned. The proteomes revealed identical pattern of stress response among stress scenarios as that indicated by physiological measurements, but allowed identification of compartment-specific stress reactions. In the symbiont, stress-response and proteolysis-related proteins were up regulated while photosynthesis-related proteins declined. In contrast, host homeostasis was maintained through chaperone up-regulation associated with elevated proteosynthesis and proteolysis, and the host metabolism shifted to heterotrophy

Short Peptides with Uncleavable Peptide Bond Mimetics as Photoactivatable Caspase-3 Inhibitors

Chemical probes that covalently interact with proteases have found increasing use for the study of protease function and localization. The design and synthesis of such probes is still a bottleneck, as the strategies to target different families are highly diverse. We set out to design and synthesize chemical probes based on protease substrate specificity with inclusion of an uncleavable peptide bond mimic and a photocrosslinker for covalent modification of the protease target. With caspase-3 as a model target protease, we designed reduced amide and triazolo peptides as substrate mimetics, whose sequences can be conveniently constructed by modified solid phase peptide synthesis. We found that these probes inhibited the caspase-3 activity, but did not form a covalent bond. It turned out that the reduced amide mimics, upon irradiation with a benzophenone as photosensitizer, are oxidized and form low concentrations of peptide aldehydes, which then act as inhibitors of caspase-3. This type of photoactivation may be utilized in future photopharmacology experiments to form protease inhibitors at a precise time and location

Improved Bioavailability and Bioaccessibility of Lutein and Isoflavones in Cultured Cells In Vitro through Interaction with Ginger, Curcuma and Black Pepper Extracts

Intestinal absorption is intrinsically low for lipophilic micronutrients and phytochemicals. Plant extracts acting as bioavailability enhancers can complement for this deficiency by modulation of both, physicochemical and biochemical parameters, in the absorption process. However, these interactions often are limited to specific conditions and the mechanisms and potential synergisms are poorly understood. In this work, we used a human intestinal cell line to characterize the impact of extracts from C. longa (curcuma), Z. officinale (ginger) and P.nigrum (black pepper) on uptake and transport rates of the xanthophylls lutein and zeaxanthin as well as soy isoflavones measured by HPLC-DAD. We found a significant increase in the uptake of lutein in the presence of curcuma extract and enhanced isoflavone transport rates mediated by curcuma and ginger extracts. Combinations of the plant extracts did not lead to any additional increase in uptake or transport rates. By investigation of mixed micelle incorporation efficiency, we could dismiss changes in bioaccessibility as a potential enhancing mechanism in our experimental setup. We further conducted a rhodamine 123 efflux assay and discovered inhibition of P-glycoproteins by the ginger and black pepper extracts, highlighting a plausible route of action leading to increased isoflavone bioavailability

Physiological responses of Amphistegina lobifera to the combined effects of ocean acidification and warming

The large benthic foraminifera Amphistegina lobifera, collected from the Gulf of Aqaba, Red Sea, in Eilat, Israel, were cultured under three pCO2 conditions (492, 963, 3182 ppm) crossed with two temperature conditions (28°C, 31°C) for two months. Patterns in protein abundance (supplementary tables of publication) were linked to the organisms' physiological responses (i.e. mortality frequency, growth rates, coloration on the L*a*b* color scale, chlorophyll a content, average pore size, pH at the foraminiferal surface during dark and light compared to seawater pH, and the resulting ∆[H+])

High-Oleic Sunflower Oil as a Potential Substitute for Palm Oil in Sugar Coatings—A Comparative Quality Determination Using Multispectral Imaging and an Electronic Nose

Palm oil has a bad reputation due to the exploitation of farmers and the destruction of endangered animal habitats. Therefore, many consumers wish to avoid the use of palm oil. Decorative sugar contains a small amount of palm oil to prevent the sugar from melting on hot bakery products. High-oleic sunflower oil used as a substitute for palm oil was analyzed in this study via multispectral imaging and an electronic nose, two methods suitable for potential large-batch analysis of sugar/oil coatings. Multispectral imaging is a nondestructive method for comparing the wavelength reflections of the surface of a sample. Reference samples enabled the estimation of the quality of unknown samples, which were confirmed via acid value measurements. Additionally, for quality determination, volatile compounds from decorative sugars were measured with an electronic nose. Both applications provide comparable data that provide information about the quality of decorative sugars