Search results for "Depsipeptide"
showing 6 items of 86 documents
Study of locomotion response and development in zebrafish (Danio rerio) embryos and larvae exposed to enniatin A, enniatin B, and beauvericin.
2021
Mycotoxins are secondary metabolites produced by a variety of fungi that contaminate food and feed resources, and are capable of inducing a wide range of toxicity. Here, we studied the developmental and behavioral toxicity in zebrafish (Danio rerio) embryos and larvae exposed to three mycotoxins: beauvericin (BEA), Enniatin A (ENN A), and Ennitain B (ENN B). Zebrafish embryos were collected after fertilization, treated individually from 1 to 6 dpf with BEA at 8, 16, 32 and, 64 μM and for both enniatins at 3.12, 6.25, 12.5 and, 25 μM. Mixture of mycotoxins were assayed as follows: i) for BEA + ENN A and BEA + ENN B at [32 + 12.5] μM and [16 + 6.25] μM; ii) for ENN A + ENN B at [12.5 + 12.5] …
Stereoselektive synthese von D-α-hydroxycarbonsäuren bzw. D-α-hydroxycarbonsäuren enthaltenden depsipeptiden aus L-aminosäuren
1985
Abstract Depsipeptides containing D-α-hydroxy carboxylic acids are efficiently synthesized by the reactions of L-α-halo-carboxylic acid esters (obtained from L-amino acids) with caesium salts of N-protected amino acids.
Synthese sterisch gehinderter Peptide und Depsipeptide nach einem Säurechlorid-Verfahren mit 2-Phosphonioethoxycarbonyl-(Peoc-)Aminosäuren und -Hydro…
1982
2-(Triphenylphosphonio)ethoxycarbonyl-(Peoc-)aminosauren 1 und -hydroxysauren 5 werden mit Oxalylchlorid in bei Raumtemp. stabile Saurechloride 2 bzw. 6 ubergefuhrt. Mit diesen aktivierten Verbindungen werden sterisch gehinderte Amidbindungen — z. B. in den geschutzten Valin-Peptiden 3a—g und in Hydroxyacyl-Dipeptiden 7 — hergestellt. Nach Schutzgruppenabspaltung aus der voll geschutzten Form 7a entsteht so die Sporidesmolsaure B (9a), die in ihren Eigenschaften mit dem Abbauprodukt aus dem Sporidesmolid I ubereinstimmt. Trotz zweimaliger Anwendung der Saurechlorid-Kondensation ist keine Racemisierung eingetreten. Syntheses of Sterically Hindered Peptides and Depsipeptides by Means of an Ac…
A new member of the fusaricidin family – structure elucidation and synthesis of fusaricidin E
2017
Two hitherto unknown fusaricidins were obtained from fermentation broths of three Paenibacillus strains. After structure elucidation based on tandem mass spectrometry and NMR spectroscopy, fusaricidin E was synthesized to confirm the structure and the suggested stereochemistry. The synthesis was based on a new strategy which includes an efficient access to the 15-guanidino-3-hydroxypentadecanoyl (GHPD) side chain from erucamide.
Lipodepsipeptides from Pseudomonas syringae are partially proteolyzed and are not absorbed by humans: An in vitro study
2008
There are some concerns about the use of Pseudomonas-based products as biocontrol agents because of the hemolytic activity shown by their metabolites. The effects of Pseudomonas lipodepsipeptides (LDPs) on mammals via ingestion and the LDP degradation during the digestion and intestinal permeability have not been evaluated. In this research, the susceptibility of different LDPs to degradation was assayed with enzymatic gastrointestinal digestion, and intestinal permeability to LDPs was investigated in an in vitro system based on an intestinal cell layer system. Results demonstrated that trypsin and chymotrypsin hydrolyze up to 50% of the various LDPs, and that proteolysis was further increa…
Aplidin® induces JNK-dependent apoptosis in human breast cancer cells via alteration of glutathione homeostasis, Rac1 GTPase activation, and MKP-1 ph…
2006
Aplidin® is an antitumor agent in phase II clinical trials that induces apoptosis through the sustained activation of Jun N-terminal kinase (JNK). We report that Aplidin® alters glutathione homeostasis increasing the ratio of oxidized to reduced forms (GSSG/GSH). Aplidin® generates reactive oxygen species and disrupts the mitochondrial membrane potential. Exogenous GSH inhibits these effects and also JNK activation and cell death. We found two mechanisms by which Aplidin® activates JNK: rapid activation of Rac1 small GTPase and downregulation of MKP-1 phosphatase. Rac1 activation was diminished by GSH and enhanced by L-buthionine (SR)-sulfoximine, which inhibits GSH synthesis. Downregulatio…