The interplay between the entropically and enthalpically favored products of peptide fragmentation is probed using a combined experimental and theoretical approach. These b2 ion products can take either an oxazolone or diketopiperazine structure. Cleavage after the second amide bond is often a favorable process because the products are small ring structures that are particularly stable. These s...

Coevolution of beneficial microorganisms with the mammalian intestine fundamentally shapes mammalian physiology. Here, we report that the intestinal microbe Bacteroides fragilis modifies the homeostasis of host invariant natural killer T (iNKT) cells by supplementing the host's endogenous lipid antigen milieu with unique inhibitory sphingolipids. The process occurs early in life and effectively...

The anti-inflammatory effect of physalin E, a seco-steroid isolated from Physalis angulata L. was evaluated on acute and chronic models of dermatitis induced by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and oxazolone, respectively, in mouse ear. The changes in ear edema/thickness, production of pro-inflammatory cytokines (TNF-alpha and IFN-gamma), myeloperoxidase (MPO) activity, and histologi...

Risk assessment of sensitizing chemicals requires, besides hazard identification, the assessment of potency. To examine the sensitizing capacity of low molecular weight chemicals, a murine local lymph node assay (LLNA) was used. The sensitizing capacity of known allergens was quantified by dose-response modeling. At a stimulatory index (SI) of 3, the corresponding estimated concentration was ca...

in the present study, a series of new substituted oxazolone derivatives (4a-4h) were synthesized by the erlenmeyer condensation of phthaloylglycylglycine with different aldehydes in the presence of anhydrous sodium acetate and acetic anhydride. the structure of newly-synthesized compounds were evaluated by elemental analyses and spectral ( uv-visible, ir, nmr, mass) studies. all the synthesized...

An efficient and high-yield procedure to prepare methyl N-benzoylamino-3-arylacrylates from unsaturated (Z)-2-aryl-4-arylidene-5-(4H)-oxazolones and Hg(OAc)2 in methanol is described herein. The observed reactivity of mercury(II) acetate here is different to its usual metallating behaviour, since it cleaves the unsaturated oxazolone ring without change of stereochemistry.