AquaticToxicology176(2016)128–140
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Aquatic Toxicology
jou rn al h om ep a ge :w w w . e l s e v i e r . c o m / l o c a t e / a q u a t o x
Diatom-derived oxylipins induce cell death in sea urchin embryos activating caspase-8 and caspase 3/7
Nadia Ruocco
a,1, Stefano Varrella
a,1, Giovanna Romano
b, Adrianna Ianora
b, Matt G. Bentley
c, Domenico Somma
d, Antonio Leonardi
d, Stefano Mellone
e, Antonio Zuppa
a, Maria Costantini
a,∗aDepartmentofBiologyandEvolutionofMarineOrganisms,StazioneZoologicaAntonDohrn,VillaComunale,80121Napoli,Italy
bDepartmentofIntegrativeMarineEcology,StazioneZoologicaAntonDohrn,VillaComunale,80121Napoli,Italy
cFacultyofScienceandTechnology,C227ChristchurchHouse,BournemouthUniversity,TalbotCampus,Poole,UK
dDipartimentodiMedicinaMolecolareeBiotecnologieMediche,UniversitàdiNapoliFedericoII,Napoli,Italy
eIstitutodiEndocrinologiaeOncologiaSperimentale,CNR,Napoli,Italy
a r t i c l e i n f o
Articlehistory:
Received30October2015
Receivedinrevisedform5April2016 Accepted13April2016
Availableonline22April2016
Keywords:
Apoptosis Caspases Diatoms Seaurchin
a b s t r a c t
Diatomsareanimportantclassofunicellularalgaethatproducebioactivesecondarymetaboliteswith cytotoxicactivitycollectivelytermedoxylipins,includingpolyunsaturatedaldehydes(PUAs),hydroxy- acids(HEPEs),oxo-acidsandepoxyalcohols.Previousresultsshowedthatathigherconcentrations,the PUAdecadienalinducedapoptosisoncopepodsandseaurchinembryosviacaspase-3activation;at lowerconcentrationsdecadienalaffectedtheexpressionlevelsofthecaspase-8geneinembryosofthe seaurchinParacentrotuslividus.Inthepresentwork,westudiedtheeffectsofothercommonoxylip- insproducedbydiatoms:twoPUAs(heptadienalandoctadienal)andfourhydroxyacids(5-,9-11-and 15-HEPE)onP.lividuscelldeathandcaspaseactivities.Ourresultsshowedthat(i)athigherconcentra- tionsPUAsandHEPEsinducedapoptosisinseaurchinembryos,detectedbymicroscopicobservation andthroughtheactivationofcaspase-3/7andcaspase-8measuredbyluminescentassays;(ii)atlow concentrations,PUAsandHEPEsaffectedtheexpressionlevelsofcaspase-8andcaspase-3/7(isolatedfor thefirsttimehereinP.lividus)genes,detectedbyRealTimeqPCR.Thesefindingshaveinterestingimpli- cationsfromtheecologicalpointofview,giventheimportanceofdiatombloomsinnutrient-richaquatic environments.
©2016TheAuthors.PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction
Echinodermsplayakeyroleinthemaintenanceoftheintegrity ofthe ecosystemwhere they live(Hereu et al.,2005), particu- larlyintheirearlyplanktoniclife stages (mostcritical fortheir survival).Theyareconstantlyexposedtoanumberofpollutants (Bellas etal., 2008a;Rosen etal.,2008).Seaurchinshavebeen adoptedasanexcellentmodelsystemtostudytheecotoxicologi- calresponseofmarineinvertebratestoenvironmentalpollutants (Geraciet al.,2004; Bonaventuraetal., 2005;Cakal Arslanand Parlak,2007;Bellasetal.,2008b;Nahonetal.,2008).Echinoderms are world-wide in their distributionand are extremely impor- tantinstructuringbenthicmarinecommunities.Maintenanceof
∗ Correspondingauthor.
E-mailaddress:[email protected](M.Costantini).
1 Theseauthorscontributedequallytothiswork.
theseanimalsandobtainingripegametesforexperimentationis relativelyeasy,developmentissensitivetoseveralkindsofenvi- ronmentalpollutants,andresultscanbeobtainedinashorttime frame(KobayashiandOkamura,2005).Thetransparentembryo enableseasyobservationofmalformation,makingitpossibleto detectsub-lethaleffectsofpollutants onmulticellularbodyfor- mationatanearlystagein development.To date,thestressors thathavebeenexaminedusingtheseaurchinasamodelinclude physico-chemicalchangesinthewater,suchasacidicpH(Dupont et al., 2010), hypoxia (Kodama et al., 2010), UV (Lesser et al., 2003;Schröderetal.,2005;Bonaventuraetal.,2005,2006;Lister etal.,2010a,2010b;Russoetal.,2010),X-rays(Matrangaetal., 2010;Bonaventuraetal.,2011),andchemicalssuchasantifoul- ingagents/pesticides(Garaventaetal.,2010;Aluigietal.,2010), endocrinedisruptors (Sugni etal.,2010;Horiguchiet al.,2010) andmetals(Pinsinoetal.,2014;Kiyomotoetal.,2010).Natural toxinsrepresenta majorsourceofstressformarineorganisms.
Inthisregard,diatomsareparticularlynoteworthy,traditionally
http://dx.doi.org/10.1016/j.aquatox.2016.04.012
0166-445X/©2016TheAuthors.PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBY-NC-NDlicense(http://creativecommons.org/licenses/by-nc-nd/4.
0/).
