ABSTRACT
Many vaccine candidates with promising results in preclinical testing fail in human trials. New complex human tissue models have the potential to improve the predictability of vaccine safety and efficacy in human clinical trials.
Subject(s)
Drug Evaluation, Preclinical , Models, Biological , Mucous Membrane/immunology , Vaccines/immunology , Bioreactors , Host-Pathogen Interactions/immunology , Humans , Immunity , PerfusionABSTRACT
Marine sponges are rich sources of natural products exhibiting diverse biological activities. Bioactivity-guided fractionation of the Red Sea sponge Callyspongia aff. implexa led to the isolation of two new compounds, 26,27-bisnorcholest-5,16-dien-23-yn-3ß,7α-diol, gelliusterol E (1) and C27-polyacetylene, callimplexen A (2), in addition to the known compound ß-sitosterol (3). The structures of the isolated compounds were determined by 1D- and 2D-NMR techniques as well as high-resolution tandem mass spectrometry and by comparison to the literature. The three compounds (1-3) were tested against Chlamydia trachomatis, an obligate intracellular gram-negative bacterium, which is the leading cause of ocular and genital infections worldwide. Only gelliusterol E (1) inhibited the formation and growth of chlamydial inclusions in a dose-dependent manner with an IC50 value of 2.3 µM.
Subject(s)
Anti-Bacterial Agents/pharmacology , Biological Products/pharmacology , Callyspongia/chemistry , Chlamydia trachomatis/drug effects , Polyynes/isolation & purification , Polyynes/pharmacology , Porifera/chemistry , Sterols/pharmacology , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Biological Products/chemistry , Biological Products/isolation & purification , Chlamydia trachomatis/growth & development , Molecular Structure , Polyynes/chemistry , Sitosterols/chemistry , Sitosterols/isolation & purification , Sitosterols/pharmacology , Sterols/chemistry , Sterols/isolation & purificationABSTRACT
The purple ink of the sea hare Aplysia punctata contains a 60 kDa protein with tumoricidal activity. This A. punctata ink toxin (APIT) kills tumor cells within 6--8h in an apoptosis independent manner by the production of high amounts of hydrogen peroxide which induce a necrotic form of oxidative stress. Here, we describe the biochemical features of APIT associated with its anti-tumor activity. APIT is a weakly glycosylated FAD-binding L-amino acid oxidase that catalyzes the oxidative deamination of L-lysine and L-arginine and thereby produces hydrogen peroxide (H(2)O(2)), ammonia (NH(4)(+)) and the corresponding alpha-keto acids. The tumoricidal effect is completely abrogated in the absence of the amino acids L-lysine and L-arginine. The enzyme is stable at temperatures from 0 to 50 degrees C. Similar to other FAD-binding enzymes, it is resistant against tryptic digest. Even digest with proteinase K fails to degrade the enzyme. Cloning of the APIT gene and subsequent sequencing revealed a FAD-binding domain followed by a so-called GG-motif, which is typical for L-amino acid oxidases. Strongest homology exists to escapin, aplysianin A precursor, the cyplasins L and S and achacin.