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— 342 MEMOIRS OF THE QUEENSLAND MUSEUM PROPAGATED ELECTRICAL IMPULSES IN A entire preparation at 0.27 ± O.lcnvs at 10°C, SPONGE. Memoirs ofthe Queensland Museum 44: presumably in the trabecular reticulum. The 342. 1999:- Previous work has shown that preparationshowsanabsoluterefractoryperiodof29s, Rhabdocalyptus dawsoni, a hexactinellid sponge, can and is relatively refractory for a further 95-100 s. arrest its feeding current following mechanical or Intracellular recordings have not been carried out but electrical stimuli. Although a propagated impulse was thewaveformrecordedextraeellularlyissuggestiveof suspected as the signal triggering arrests, numerous a conventional, overshooting spike. Pharmacological attempts to record such an event failed due to the evidence suggests that it is calcium-based. Thus, porous character ofthe tissue and extreme fragility of despite its long refractory period and low conduction the surface membranes. Usinga new approach, which velocity the system is functionally equivalent to the involves dissociating sponge tissue, letting it through-conductingnervenetsand excitableepithelial G reaggregate,andgraftingitbackontothespongeasan conduction systems of other animals. Porifera, autograft, we have found it possible to record hexactinellid, Rhabdocalyptus, conduction, propagatedelectrical impulses.Thegraftsfusewiththe electrophysiology, behaviour,pumping. trabecular reticulum, a syncytial tissue that penetrates all parts of the body, including the flagellated Sally P. Leys* (email: [email protected]) & George O. chambers,andareeventuallyabsorbedintothesponge. Mackie, Department ofBiolog\: University of Victoria, But forawhilethey form solid lumpsthatcanbeused British Columbia, V8W3N5, Canada: *Presentaddress: for attachment of suction recording electrodes. Department ofZoology and Entomology', Molecular- Impulses are all-or-none events evoked by single Zoology Laboratory, UniversityofQ*~ueensland, StLucia, electrical shocks that propagate diffusely through the Qld. 4072, Australia: 1June 199$. THEONELLAPEPTOLIDES FROM THE much less cytotoxic. This implied that the second DEEP-WATER NEW ZEALAND SPONGE residue from N-terminus (X) plays a key role in LAMELLOMORPHA STRONGYLATA. Memoirsof maintainingbioactivity. the Queensland Museum 44: 342. 1999:- The deep- Acomparison withtheknowntheonellapeptolide Id watermarinesponge,Lamellomorphastrongylata, was suggested that the crystal structure ofIIle is similar to collected bv benthic dredginaat 80m on the Chatham that ofId although four residues are changed and the Rise(200kmofftheECoastoftheSouthIslandofNew ringsize is 36 in Hie, not37as in Id. Zealand). Besides the previously reported calyculins, Thetheonellapeptolidesfromthe I andIIserieshave calyculinamides and swinholide H, five new all been isolated previously from Lithistid sponges, tridecapeptides, theonellapeptolides Ilia, b, c, d and e, while those from the III group are nominally from a wereobtained (Fig. 1). different sponge order. A key question still to be Thefollowingstrategywasusedfordeterminingthe adressediswhetherornotallthreegroupsofpeptolides G structures of the theonellapeptolides: 1) the amino have a similar, or comparable, symbiont origin ? acids were established by GC/MS following acid Porifera, peptolides, amino acids, nmr spectroscopy, hydrolysis and derivatization; 2) methanolysis gave a Ic/ms, gc/ms, chiral hplc. X-ray crystallography, linear peptide, which was sequenced by tandem mass symbionts, Lithistida, Theonella sp., Lamellomorpha spectrometry; 3) isobaric residues were distinguished strongylata. NewZealand. by2DNMRexperiments;4)detailedanalysisledtothe complete NMR assignment; 5) the absolute S. Li,J. W.Blunt, E.J. Dumdei& M. H. G. Munro (email: stereochemistry of Hie was determined by X-ray m.munro(d\chem.canterbury,ac.nz), Department of crystallography coupled with chiral HPLC; 6) the Chemistry, University ofCanterbury, Christchurch, New stereochemistry ofthe otherpeptides were established Zealand: L K Pannell & N. Shigematsu, Laboratory of byan LC/MS method. Analytical Chemistry, NIDDK, N1H, Bethesda, MD Theonellapeptolides Illb, c, d and e showed mild 20892-0805. USA: 1June 1998, cytotoxicity against P388 cell line, but Ilia was very CO CH,OCH -Val- Theonellapeptolides flla to e: Thr N-Me[iAla Y Z - pAla (aj X=N-MeHyMet, Y=Val, Z=N-Melle (b) X=N-MeAla, Y=Val, Z=N-Melle (c) X=Leu. Y=N~MeAla, Z=N-Melle N-MeLeu (d) X=N-MeLeu. Y=Val, Z=N-MeVal (e) X=N-Mel_eu, Y=Val, Z=N-Melle LeIu Ala N-MeAla N-Melle lie FIG. I. Structures oftheonellapeptolides from Lamellomorphastrongylata.