Synthesis and evaluation of locostatin-based chemical probes towards PEBP-proteins

<p>Phosphatidyl ethanolamine-binding proteins (PEBPs) are implicated in various critical physiological processes in all eukaryotes. Among them is Flowering Locus T (FT), the protein recently discovered as the vital flowering hormone in plants. Small molecule inhibitors and activators of FT could provide control over plant flowering and are therefore an interesting target for industrial agriculture. No small molecule inhibitors or activators are known for FT, but for a structurally similar PEBP, RKIP, an inhibitor called locostatin has been reported to covalently bind in the RKIP ligand binding pocket. Herein, we report the synthesis of novel locostatin-based chemical PEBP probes and evaluate their ability and selectivity towards the binding of FT and RKIP.</p

Synthesis and evaluation of locostatin-based chemical probes towards PEBP-proteins

Phosphatidyl ethanolamine-binding proteins (PEBPs) are implicated in various critical physiological processes in all eukaryotes. Among them is Flowering Locus T (FT), the protein recently discovered as the vital flowering hormone in plants. Small molecule inhibitors and activators of FT could provide control over plant flowering and are therefore an interesting target for industrial agriculture. No small molecule inhibitors or activators are known for FT, but for a structurally similar PEBP, RKIP, an inhibitor called locostatin has been reported to covalently bind in the RKIP ligand binding pocket. Herein, we report the synthesis of novel locostatin-based chemical PEBP probes and evaluate their ability and selectivity towards the binding of FT and RKIP

Synthesis and evaluation of locostatin-based chemical probes towards PEBP-proteins

Phosphatidyl ethanolamine-binding proteins (PEBPs) are implicated in various critical physiological processes in all eukaryotes. Among them is Flowering Locus T (FT), the protein recently discovered as the vital flowering hormone in plants. Small molecule inhibitors and activators of FT could provide control over plant flowering and are therefore an interesting target for industrial agriculture. No small molecule inhibitors or activators are known for FT, but for a structurally similar PEBP, RKIP, an inhibitor called locostatin has been reported to covalently bind in the RKIP ligand binding pocket. Herein, we report the synthesis of novel locostatin-based chemical PEBP probes and evaluate their ability and selectivity towards the binding of FT and RKIP

2018 - Monitoring dioxins, PCBs and flame retardants in agricultural and fishery products

On behalf of the Ministry of Agriculture, Nature and Food Quality (LNV), Wageningen Food Safety Research analyses samples of agricultural products of animal origin for dioxins, PCBs, brominated flame retardants (BFRs) and poly- and perfluorinated alkyl substances (PFASs). This includes meat, milk, eggs and fish. The samples are taken at the primary production or processing stage (e.g. in slaughterhouses or raw milk collection services). For dioxin-like compounds, 350 samples are first screened with the DR CALUX® method. Samples giving a signal indicating a level above the lowest action level are regarded as suspected. These samples are further examined using GC/HRMS as confirmatory method. Concerning fish, shellfish and crustaceans, approx. 25 samples are collected at sea by research vessels, at the fish auction, or from whole-sale traders (farmed fish)

A plant-based chemical genomics screen for the identification of flowering inducers

Background: Floral timing is a carefully regulated process, in which the plant determines the optimal moment to switch from the vegetative to reproductive phase. While there are numerous genes known that control flowering time, little information is available on chemical compounds that are able to influence this process. We aimed to discover novel compounds that are able to induce flowering in the model plant Arabidopsis. For this purpose we developed a plant-based screening platform that can be used in a chemical genomics study. Results: Here we describe the set-up of the screening platform and various issues and pitfalls that need to be addressed in order to perform a chemical genomics screening on Arabidopsis plantlets. We describe the choice for a molecular marker, in combination with a sensitive reporter that's active in plants and is sufficiently sensitive for detection. In this particular screen, the firefly Luciferase marker was used, fused to the regulatory sequences of the floral meristem identity gene APETALA1 (AP1), which is an early marker for flowering. Using this screening platform almost 9000 compounds were screened, in triplicate, in 96-well plates at a concentration of 25μM. One of the identified potential flowering inducing compounds was studied in more detail and named Flowering1 (F1). F1 turned out to be an analogue of the plant hormone Salicylic acid (SA) and appeared to be more potent than SA in the induction of flowering. The effect could be confirmed by watering Arabidopsis plants with SA or F1, in which F1 gave a significant reduction in time to flowering in comparison to SA treatment or the control. Conclusions: In this study a chemical genomics screening platform was developed to discover compounds that can induce flowering in Arabidopsis. This platform was used successfully, to identify a compound that can speed-up flowering in Arabidopsis.</p

Perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorononanoic acid (PFNA) increase triglyceride levels and decrease cholesterogenic gene expression in human HepaRG liver cells

Per- and polyfluoroalkyl substances (PFASs) are omnipresent in the environment, food chain, and humans. Epidemiological studies have shown a positive association between serum levels of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), and increased serum cholesterol and, in some cases, also triglyceride levels. However, causality has been questioned, as animal studies, as well as a human trial, showed a decrease in serum cholesterol and no effects or a decrease in plasma triglycerides. To obtain more insight into the effects of PFASs on these processes, the present study investigated the effects of PFOA, PFOS, and perfluorononanoic acid (PFNA) on intracellular triglyceride and cholesterol levels in human HepaRG liver cells. DNA microarray analyses were performed to provide insight into underlying mechanisms. All PFASs induced an increase in cellular triglyceride levels, but had no effect on cholesterol levels. Gene set enrichment analysis (GSEA) of the microarray data indicated that gene sets related to cholesterol biosynthesis were repressed by PFOA, PFOS, and PFNA. Other gene sets commonly affected by all PFAS were related to PERK/ATF4 signaling (induced), tRNA amino-acylation (induced), amino acid transport (induced), and glycolysis/gluconeogenesis (repressed). Moreover, numerous target genes of peroxisome proliferator-activated receptor α (PPARα) were found to be upregulated. Altogether, the present study shows that PFOA, PFOS, and PFNA increase triglyceride levels and inhibit cholesterogenic gene expression in HepaRG cells. In addition, the present study indicates that PFASs induce endoplasmic reticulum stress, which may be an important mechanism underlying some of the toxic effects of these chemicals.</p