February 1st to 5th 2016
Olhão, Portugal
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Mapping of the chemosensory system in Holothuria arguinensis

Scientific Exhibition
Natural Resources
Wednesday, February 3, 2016 -
18:30 to 20:00

Marquet, N. 1 Power, D.M. 2 Hubbard, P.C. 3 Canario, A.V.M. 4

1Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
2CCMAR-CIMAR Laboratorio Associado, Universidade do Algarve, Faro, Portugal
3CCMAR-CIMAR Laboratorio Associado, Universidade do Algarve, Faro, Portugal
4CCMAR-CIMAR Laboratorio Associado, Universidade do Algarve, Faro, Portugal

There is a growing interest in sea cucumbers in Europe, while at the same time they are already being over-exploited in many parts of the world. Thus attempts are starting to cultivate them at an industrial scale. However, little is known about their biology and life strategy, hindering decisions on population management. In particular, the role of chemical cues has been largely ignored. Previous studies indicated that the mucus and perivisceral coelomic fluid as sources of chemical cues. Information about the nature of these compounds, the sensory mechanisms involved and the effects elicited are scarce. An important step in studying chemical communication is to have a clear map of the organization of the sensory system in the target organism. The present study was performed to characterize the major tissue(s) in contact with the environment in order to generate a map of the sensory system in sea cucumbers. The animals were dissected and divided into four regions: anterior, posterior, dorsal and ventral. As a first step, classical histology was used to characterise each of these regions. They had a common organisation and possessed an outer cuticle, over the epidermis, a nerve plexus and a wide zone of connective tissue in which water vascular canals were observed. Three ambulacral appendages were present in the body of the sea cucumbers: (1) tentacles surrounding the mouth, (2) tube feet distributed along the body and (3) papillae organized in rows on the dorsal region. The results obtained and the previous studies suggest that tentacles are sensory organs and could potentially have a role in perception of chemical signals. They consist of a stem divided into secondary and tertiary branches ending in a papilla formed by several highly innervated buds. The next step of this work will use next generation sequencing to identify potential chemosensory receptors in tentacles and bioassays that demonstrate responses to chemical signals.
tissue, Holothuria arguinensis, histology, sensory organs

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