Article

Aldehyde-encapsulating liposomes impair marine grazer survivorship.

Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy.
Journal of Experimental Biology (impact factor: 3). 06/2008; 211(Pt 9):1426-33. DOI:10.1242/jeb.015859
Source: PubMed

ABSTRACT In the last decade, there has been an increased awareness that secondary metabolites produced by marine diatoms negatively impact the reproductive success of their principal predators, the copepods. Several oxylipins, products of the enzymatic oxidation of fatty acids, are produced when these unicellular algae are damaged, as occurs during grazing. In the past, the dinoflagellate Prorocentrum minimum, which does not produce the oxylipin 2-trans,4-trans-decadienal (DD), has been used as a live carrier to calculate daily ingestion rates of this molecule by copepod crustaceans. However, since the interaction between oxylipins and live carriers is unknown, the question as to how much and for how long ingestion of these molecules affects copepod reproduction remains a critical point to understanding the functional role of such compounds at sea. In the investigation presented here we used giant liposomes ( approximately 7 mum) as a delivery system for the oxylipin DD, prepared in the same size range as copepod food and containing known amounts of DD. The aim of this work was to relate the ingestion of DD to the reproductive failure of the copepods Temora stylifera and Calanus helgolandicus. Liposomes were very stable over time and after 10 days of feeding, liposomes encapsulating DD reduced egg hatching success and female survival with a concomitant appearance of apoptosis in both copepod embryos and female tissues. Concentrations of DD inducing blockage were one order of magnitude lower that those used in classical feeding experiments demonstrating that liposomes are a useful tool to quantitatively analyze the impact of toxins on copepods.

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Keywords

carriers
 
concomitant appearance
 
copepod crustaceans
 
copepod embryos
 
copepod food
 
copepod reproduction
 
copepods Temora stylifera
 
critical point
 
DD inducing blockage
 
delivery system
 
dinoflagellate Prorocentrum minimum
 
egg hatching success
 
giant liposomes
 
increased awareness
 
liposomes encapsulating DD
 
live carrier
 
magnitude lower
 
marine diatoms
 
oxylipin DD
 
useful tool