Distribution of the sea squirt <i>Ecteinascidia thurstoni</i> Herdman, 1890 (Ascidiacea: Perophoridae) along Suez Canal and Egyptian Red Sea coasts

• Main Author: Ali A-F. A. Gab-Alla
• Format: Article
• Language: English
• Published: Elsevier 2008-06-01
• Series: Oceanologia
• Subjects: Distribution; Ascidian; Tunicate; Sea squirt; Ecteinascidia thurstoni; Red Sea; Suez Canal
• Online Access: http://www.iopan.gda.pl/oceanologia/50_2.html#A7

<i>Ecteinascidia thurstoni</i> is a colonial sea squirt. It has a seasonal rhythm and a tropicaland subtropical distribution; it is usually present during the summer months.It synthesizes a group of molecules called ecteinascidins. One of these is ET-743, a compound that has a most original anti-tumoral activity and is today considered to be one of the most promising substances effective against various solid-type tumors (currently sold under the trade name of Yondelis for the treatment of sarcomas and related tumors; it is undergoing phase II/III clinical trails for other kinds of tumors).Worldwide, <i>Ecteinascidia</i> species represent the only available source of this bioactivecompound, which was first discovered in <i>E. turbinata</i>.During the present study, the ecology of <i>E. thurstoni</i> along the Suez Canal and Red Seawas investigated. Its populations were observed to be highly gregarious due in partto their low larval dispersal, which is very localized; larvae therefore tendto settle close to their parent colonies. It is only recorded in shallow waters (0.5-1.5 m)as an epiphyte on the pneumatophores of mangroves by the Red Sea, on the pilings of jetties,and the metal or cement banks of the Suez Canal. The morphometric characteristics(zooid length, zooid weight, colony weight) of the Suez Canal population differsignificantly from those of the Red Sea. Studying the distribution of this speciesand locating its different populations along the Suez Canal and Red Sea could helpto characterize their genetics, chemistry and bacterial communities at differentisolated locations.Ultimately, this will help to define the sources of ET-743 and hence promote itsbiosynthesis on a commercial scale.