CONTENT - International Society of Zoological Sciences
CONTENT - International Society of Zoological Sciences
CONTENT - International Society of Zoological Sciences
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S20 ICZ2008 - Abstracts<br />
Dispersal and colonization strategy <strong>of</strong> the whale bone eating<br />
worm Osedax<br />
Florence Pradillon, Masaru Kawato, Katsunori Fujikura, Chikayo<br />
Noda and Yoshihiro Fujiwara<br />
Extremobiosphere Research Center, Japan Agency for Marine-<br />
Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho,<br />
Yokosuka, Kanagawa, Japan<br />
In the deep-sea, whale falls bring massive organic enrichment in<br />
single pulses that significantly impact on local deep-sea<br />
communities. Whale falls provide island habitat for a specialized<br />
fauna adapted to live on whale remains 1 . The Siboglinid<br />
polychaetes Osedax exhibit a unique relationship to whale bones.<br />
Females grow a root organ that harbor symbiotic heterotrophic<br />
bacteria and that infiltrate bones and extract lipid and collagen for<br />
nutrition 2 . Since the discovery <strong>of</strong> this genus, 10 species have been<br />
reported, all associated to decaying bones, but in a wide range <strong>of</strong><br />
environmental condition 3-6 . The success <strong>of</strong> Osedax in colonizing<br />
such a patchy habitat over broad geographic and bathymetric<br />
ranges implies efficient dispersal and colonization strategies.<br />
We analyzed colonization patterns <strong>of</strong> Osedax species on a sperm<br />
whale carcass implanted at 925 m depth in Sagami Bay (Japan).<br />
Seven different species successively colonizing the bones were<br />
identified using molecular techniques. O. japonicus that colonizes<br />
a close but shallow (225 m) sperm whale fall site 7 was not found,<br />
whereas 2 <strong>of</strong> the early colonists in Sagami Bay are also known<br />
from distant sites in the western Pacific (<strong>of</strong>f California). This<br />
suggests very efficient dispersal possibly limited by depth related<br />
environmental parameters. We investigated embryonic and larval<br />
development in order to understand mechanisms underlying<br />
dispersal and colonization efficiency. Embryonic development<br />
exhibits remarkably rapid rates even at low temperature. This<br />
feature is usually associated with short dispersal range, suggesting<br />
that spatial and temporal frequency <strong>of</strong> suitable bones may be<br />
essential for maintaining Osedax population.<br />
Disclosing chemosynthesis in bivalve species from mud<br />
volcanoes in the gulf <strong>of</strong> Cadiz<br />
Clara F. Rodrigues, Gordon Webster, Andrew Weightman and<br />
Marina R. Cunha<br />
Campus Universitario de Santiago, 3810-093, Aveiro, Portugal<br />
Symbiotic associations with thiotrophic and methanotrophic<br />
bacteria occur in a wide array <strong>of</strong> animal species that live in<br />
reducing environments with high sulfide and methane<br />
concentrations, such as hydrothermal vents, deep-sea whale fall,<br />
sunken wood, and cold seeps. Since the discovery in 1999 <strong>of</strong> the<br />
first mud volcano in the Gulf <strong>of</strong> Cadiz, about 30 other sites at<br />
depths ranging from 200 to 3900 m, with varying degrees <strong>of</strong><br />
hydrocarbon-rich gas seepage activity have been located and<br />
sampled. Chemosynthetic bivalve species include the widespread<br />
species Acharax sp. and Solemya sp but also other species like<br />
Lucinoma sp., Thyasira vulcolutre and Bathymodiolus mauritanicus.<br />
Stable isotopes analyses 13 C, 15 N, 34 S) show the major role <strong>of</strong><br />
chemoautotrophic derived C in the food web <strong>of</strong> mud volcanoes. 13 C<br />
values measured in solemyids, lucinid and thyasirids specimens<br />
support the hypothesis <strong>of</strong> a thiotrophic nutrition. On the other hand,<br />
isotopic signatures <strong>of</strong> Bathymodiolus specimens collected were in<br />
line for methanotrophic nutrition. Molecular identification <strong>of</strong><br />
chemosynthetic prokaryotic endosymbionts associated with these<br />
species was carried out using PCR-DGGE analysis <strong>of</strong> bacterial<br />
16S rRNA genes and analysis <strong>of</strong> bacterial clone libraries.<br />
Phylogenetic analysis <strong>of</strong> 16S rRNA genes from the gill tissues<br />
indicate that the bacterial sequences found were related to sulfuroxidizing<br />
endosymbionts from other deep-sea chemosynthetic<br />
environments. The divergence observed for Bathymodiolus<br />
mauritanicus (stable isotope values extremely depleted in 13 C<br />
suggested methano-trophic nutrition but molecular studies<br />
revealed the presence <strong>of</strong> sulfur-oxidizing bacteria) may be<br />
indicative <strong>of</strong> the occurrence <strong>of</strong> dual symbiosis but only further<br />
studies can corroborate that.<br />
- 84 -<br />
Transcriptomics study <strong>of</strong> the annelid host Riftia pachyptila<br />
symbiotic with chemosynthetic bacteria<br />
Sophie Sanchez 1 , Stéphane Hourdez 2 and François H. Lallier 2<br />
1Equipe<br />
Horloge circadienne, Laboratoire Arago, BP 74, 66650<br />
Banyuls sur mer, France<br />
2,<br />
Equipe Ecophysiologie : Evolution et Adaptation Moléculaires,<br />
Station Biologique, BP 74, 29680 Rosc<strong>of</strong>f, France<br />
The giant hydrothermal vent tubeworm Riftia pachyptila (Siboglinid<br />
Polychaete Annelid) is probably one <strong>of</strong> the most extensively<br />
studied organisms that are symbiotic with sulfide-oxidizing bacteria.<br />
Located in a specialized internal organ, the trophosome (TR),<br />
these symbionts depend on the host for their supply in O2, CO2<br />
and H2S that are acquired from the environment by the branchial<br />
plume (BR) <strong>of</strong> the worm. We used a global molecular approach by<br />
Subtractive Suppression Hybridization (SSH) to try to identify<br />
proteins involved in the metabolites exchanges in these tissues.<br />
Four subtractive cDNA libraries were constituted, with the body<br />
wall (BW) as a reference tissue (BR-BW, BW-BR, TR-BW, BW-<br />
TR). More than 700 sequences were obtained with an average <strong>of</strong><br />
45 different cDNAs per library, <strong>of</strong> which half could be identified.<br />
The differential expression <strong>of</strong> the most interesting transcripts was<br />
confirmed by quantitative PCR. A new carbonic anhydrase<br />
transcript (RpCAbr) specifically expressed in the gills was obtained<br />
in addition to the one already known (RpCAtr) that is mostly<br />
expressed in the trophosome (checking by fluorescent in situ<br />
hybridization). A myohemerythrin transcript, obtained in the TR-<br />
BW library, appears clearly specific <strong>of</strong> the trophosome tissue.<br />
Given that it is a particularly rare pigment in Annelids, this<br />
transcript was overexpressed in a heterologous system to explore<br />
a more functional aspect. In the branchial plume tissue, the Major<br />
Vault Protein could constitute an interesting clue for further studies<br />
about the transport <strong>of</strong> metabolites.<br />
Changes in lipid quality and fatty acids pr<strong>of</strong>ile <strong>of</strong> sardine oil<br />
(Sardina pilchardus) during storage: The effects <strong>of</strong><br />
temperature and α-tocopherol<br />
Salah Selmi 1 , Nawzet Bouriga 2 , S. Sadok 1 , Irineu Batista 3 , Narcisa<br />
Bandarra 3 and Maria Leonor Nunes 3<br />
1<br />
Institut National des <strong>Sciences</strong> et Technologies de la Mer, Port La<br />
Goulette 2060, Tunisia<br />
2<br />
Unité de Biologie marine, Faculté des <strong>Sciences</strong> de Tunis, 2092<br />
Campus universitaire, Tunisia<br />
3<br />
Department <strong>of</strong> Technological Innovation and Upgrading <strong>of</strong><br />
Fishery Products, INRB/IPIMAR, Av. de Brasília, 1449-006 Lisboa,<br />
Portugal<br />
Sardine oil obtained through industrial mince preparation was<br />
stored at two different temperatures (+4C° and +35°C) during 28<br />
days with or without the addition <strong>of</strong> α-tocopherol. The peroxide<br />
values and fatty acid composition were determined to monitor<br />
oxidative lipid changes during storage. Peroxide values increased<br />
significantly (p < 0.05) during storage to reach 4.36 mEq O2/kg oil<br />
and 24.9 mEq O2/kg oil at +4°C and +35°C, respectively. Oil<br />
treated with α-tocopherol showed lower hydroperoxyde levels than<br />
did the control lot (3.3 mEq O2/kg oil and 21.47 mEq O2/kg oil at<br />
+4°C and +35°C, respectively).<br />
At +4°C, saturated and monounsaturated fatty acids remained<br />
constant after storage. Polyunsaturated fatty acids (34.05%)<br />
decreased significantly at the end <strong>of</strong> storage (31.3%). At +35°C, a<br />
50% decrease <strong>of</strong> polyunsaturated fatty acids was observed after<br />
28 days <strong>of</strong> storage, reaching 18.2%. Saturated and<br />
monounsaturated fatty acids instead showed a significant increase.<br />
It is concluded that α-tocopherol has a positive affect on the<br />
oxidation <strong>of</strong> sardine oil stored at +35°C.