Cytotoxicity of diatom-derived oxylipins in organisms belonging to different phyla

Abstract

The cytotoxicity of several saturated and unsaturated marine diatom-derived aldehydes and an oxo-acid have been screened in vitro and in vivo against different organisms, such as bacteria, algae, fungi, echinoderms, molluscs and crustaceans. Conjugated unsaturated aldehydes like 2E,4E-decadienal, 2E,4E-octadienal, 5E,7E-9-oxo-nonadienoic acid and 2E-decenal were active against bacteria and fungi and showed weak algicidal activity. By contrast, the saturated aldehyde decanal and the non-conjugated aldehyde 4Z-decenal had either low or no significant biological activity. In assays with oyster haemocytes, 2E,4E-decadienal exhibited a dose-dependent inhibition of cytoskeleton organisation, rate of phagocytosis and oxidative burst and a dose-dependent promotion of apoptosis. A maternal diatom diet that was rich in unsaturated aldehydes induced arrest of cell division and apoptotic cell degradation in copepod embryos and larvae, respectively. This wide spectrum of physiological pathologies reflects the potent cell toxicity of diatom-derived oxylipins, in relation to their non-specific chemical reactivity towards nucleophilic biomolecules. The cytotoxic activity is conserved across six phyla, from bacteria to crustaceans. Deregulation of cell homeostasis is supposed to induce the elimination of damaged cells through apoptosis. However, efficient protection mechanisms possibly exist in unicellular organisms. Experiments with a genetically modified yeast species exhibiting elevated membrane and/or cell wall permeability suggest that this protection can be related to the inability of the oxylipin compounds to enter the cell.

Dose-dependent regulation of microbial activity on sinking particles by polyunsaturated aldehydes: Implications for the carbon cycle

“…5). On the other hand, PUAs are known Michael acceptors, which are highly reactive toward -NH 2 and/or -SH groups, with the potential to cause unspecific damage inside bacterial cells (46); Michael reactions could explain PUAs' inhibitory effects at high concentrations. Clearly, additional work is necessary to understand the cellular and molecular bases for the impact of PUAs on marine bacteria in sinking particles.…”

A Multifunctional Lipoxygenase with Fatty Acid Hydroperoxide Cleaving Activity from the Moss Physcomitrella patens

“…Like most ␣,␤,␥,␦-unsaturated aldehydes, 12-ODTE exhibits antiproliferative activity against fast growing and dividing cells (33,34). The 12-ODTE producing PpLOX1 might accordingly be regarded as enzyme involved in an activated chemical defense of P. patens although pathogens or herbivores that might be targeted by this chemical are not identified as of yet.…”

Antimicrobial activity of ethyl acetate extract of <i>Citrullus lanatus</i> seeds

“…Additionally auto oxidation of unsaturated fatty acids create short chain aldehydes which have antibacterial activities [17]. Acridine and it derivatives are known to possess bacteriostatic activity against many Gram positive and Gram negative bacterial [18]. The presence of hexamethyl -2-ethylacridine in this extract may be responsible for the observed bacteriostatic action against B. subtilis and C. albicans…”