Aquaculture Trials for the Production of Biologically Active Metabolites in the New Zealand Sponge Mycale Hentscheli (Demospongiae: Poecilosclerida)
Total Page：16
File Type：pdf, Size：1020Kb
Aquaculture 250 (2005) 256–269 www.elsevier.com/locate/aqua-online Aquaculture trials for the production of biologically active metabolites in the New Zealand sponge Mycale hentscheli (Demospongiae: Poecilosclerida) Michael J. Pagea,*, Peter T. Northcoteb, Victoria L. Webbc, Steven Mackeyb, Sean J. Handleya aNational Institute of Water and Atmospheric Research Ltd. (NIWA), P.O. Box 893 Nelson, New Zealand bSchool of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600 Wellington, New Zealand cNational Institute of Water and Atmospheric Research Ltd. (NIWA), P.O. Box 14 901 Kilbirnie, Wellington, New Zealand Received 11 February 2004; received in revised form 26 April 2005; accepted 29 April 2005 Abstract Genetically identical explants of the New Zealand marine sponge Mycale hentscheli were cultured in two different habitats at 7 m depth using subsurface mesh arrays to determine the effect of environment on survival, growth and biosynthesis of the biologically active secondary metabolites, mycalamide A, pateamine and peloruside A. Two 27 cm3 explants were excised from each of 10 wild donor sponges at Capsize Point, Pelorus Sound. One explant from each donor sponge was grown in arrays next to the wild donor sponge population for 250 days, while the second explant from each donor was translocated and grown at 7 m at Mahanga Bay, Wellington Harbour for 214 days. Growth rate measured by surface area and survival of explants was monitored in situ using a digital video camera. Explant surface area correlated positively with blotted wet weight (r2 =0.93). The mean concentration of each of the three compounds was determined analytically from 1H NMR spectra of replicate 30-g samples from each of 10 donor sponges at the start of the trial, and compared to mean concentrations in donors and explants at the end of the trial. Phenomenal growth rates were achieved for explants both at Capsize Point (3365F812%, 95% CI) and Mahanga Bay (2749F1136%, 95% CI). Explant survival was high: 100% at Capsize Point and 90% at Mahanga Bay. Wild donor sponges regressed in size and experienced 40% mortality by the end of the trial. Mycalamide A was present in relatively high concentrations in donors and explants throughout the trial. Pateamine was more variable among individuals and was present at lower concentrations in Capsize explants at the end of the trial. Peloruside A was highly variable among wild donor sponges. Only 50% of donors contained detectable concentrations of peloruside A, and only those sponges and their explants grown in their native environment at Capsize Point continued to biosynthesise peloruside A. No explants at Mahanga Bay contained peloruside A after 214 days in culture, indicating the production of this compound may be environmentally controlled. Our results demonstrate that in-sea aquaculture of M. hentscheli is a viable method for supply of mycalamide A, pateamine and peloruside A, and that * Corresponding author. E-mail address: [email protected] (M.J. Page). 0044-8486/$ - see front matter D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.aquaculture.2005.04.069 M.J. Page et al. / Aquaculture 250 (2005) 256–269 257 environmental conditions may be critical for the biosynthesis of peloruside A. Furthermore, results show the potential to establish cultivars to maximize peloruside A yield. D 2005 Elsevier B.V. All rights reserved. Keywords: Mycale hentscheli; Sponge; Secondary metabolites; Culture; Drug supply 1. Introduction gests that production of bioactive metabolites may be a viable option in the future for industrial supply Secondary metabolites from marine organisms are (Pomponi, 1999). However, culture optimisation is a rich source of novel chemical compounds (Faulkner, still only in its primary stages and further experimen- 2001), many of which are biologically active. Since tation is needed to improve in vitro conditions specific the first pharmaceutically important compounds were to sponge cells (Rinkevich, 1999). isolated from a sponge (Bergmann and Feeney, 1951), In-sea and land-based aquaculture systems remain the marine environment has become a major resource the most cost-effective medium-term production for collection and screening of organisms for discov- methods for supply of biologically active compounds ery of new drugs (Blunt et al., 2004; Mendola, 2003). from marine organisms. Favourable growth rates have Of all marine fauna, sponges are considered to be the been achieved in experimental closed systems (e.g., best source of novel bioactive compounds (Ireland et Belarbi et al., 2003; Duckworth et al., 2003; Osinga et al., 1993; Munro et al., 1999). Many sponges have al., 1999, 2003) that enable greater control of envi- been shown to contain compounds with promising ronmental conditions, but these systems have yet to be antiviral (Bergmann and Burke, 1955; Perry et al., trailed on a commercial scale. In contrast, in-sea 1988), anti-microbial (Cariello et al., 1982; Green et systems for supply of anticancer compounds can be al., 1985; McCaffrey and Endean, 1985), anti-inflam- economically viable at a larger scale. For instance, matory (Potts et al., 1992; Schmidt and Faulkner, production of Bryostatin 1, from the bryozoan Bugula 1996) and anti-tumour (Gunasekera et al., 1990; neritina, and ectinascidin 743, from the ascidian Ecti- Litaudon et al., 1997) activity. nascidia turbinata, have proved cost-effective (Men- Supply of natural compounds from wild sponges dola, 2003), and aquaculture trials on biologically can be a major factor limiting pharmaceutical devel- active sponges have also demonstrated relatively opment (e.g., Dumdei et al., 1998; Pomponi, 2001; high growth rates and retention of biological activity Sennet, 2001). Target compounds often occur in the in culture (e.g., Battershill and Page, 1996; Duck- sponge in trace amounts and continuous supply from worth and Battershill, 2003a; Mu¨ller et al., 1999; wild populations cannot provide enough for pre-clin- Munro et al., 1999). ical studies (Dumdei et al., 1998). Of the supply The New Zealand endemic marine sponge Mycale options available, wild harvest is often not ecologi- hentscheli Bergquist and Fromont (Demospongiae: cally sustainable (Battershill and Page, 1996). Chem- Poecilosclerida: Mycalidae) is a soft fleshy sponge ical synthesis is an alternative; however, the molecules of massive to encrusting morphology that inhabits are often complex and their multi-step synthesis is subtidal reefs from 5 to 30 m. This sponge contains seldom amenable to industrial processes (Sennet, three classes of biologically active compounds with 2001). For compounds localized in sponge microbial pharmaceutical potential: mycalamide A, pateamine associates (e.g., Bewley et al., 1996; Unson et al., and peloruside A. The mycalamides (A–D) were the 1994), isolation and culture in marine bioreactors first group of novel cytotoxic compounds to be iso- could lead to an industrially feasible supply option lated from M. hentscheli. They have been reported to (Pomponi, 2001). Nevertheless, a significant propor- be potent protein synthesis inhibitors and have recent- tion of biologically active compounds are localized in ly been found to cause apoptosis (Hood et al., 2001). the host sponge cells themselves (e.g., Salomon et al., Pateamine, a biochemically unrelated macrolide iso- 2001; Thompson et al., 1983; Uriz et al., 1996). In lated from M. hentscheli, is also a potent eukaryotic vitro culture of cell lines of bioactive sponges sug- cytotoxin active in the sub-nanomolar range (North- 258 M.J. Page et al. / Aquaculture 250 (2005) 256–269 cote et al., 1991). It has subsequently been found to al., 2004) and is in progress for peloruside A (Liu and have immunosuppressive and apoptotic properties Zhou, 2004); however, immediate sustainable supply (Hood et al., 2001; Romo et al., 1998). The most is critical for continuing research. In the short- to recently discovered and potentially valuable cytotoxic medium-term aquaculture is the only reliable method metabolite isolated is peloruside A. This compound of supply. was isolated from specimens of M. hentscheli collect- The primary objective of our study was to deter- ed from Pelorus Sound on the north coast of the South mine the aquaculture potential for supply of biologi- Island (West et al., 2000). Peloruside A is structurally cally active target compounds from M. hentscheli by: unrelated to either the mycalamides or pateamine and (1) quantifying survival and growth rates of explants yet is also a potent eukaryotic cytotoxin. Recently, we in different environmental conditions and (2) deter- have found that peloruside A is a microtubule stabi- mining the influence of environment and explant liser with potency and mode of action similar to the identity on metabolite biosynthesis of M. hentscheli naturally derived anticancer drug TaxolR. Pre-clinical sponges in aquaculture. trials are currently being conducted on peloruside A for development as a new anti-tumour drug. All three compounds derived from M. hentscheli have very 2. Methods similar profiles of toxicity to a range of organisms and cell lines, and are therefore impossible to distin- 2.1. Site descriptions guish using biological assay-based analytical techni- ques. However, in a recent study, we developed an Capsize Point is situated in Pelorus Sound at the analytical method using 1H NMR to quantify the northern end of the South Island of New Zealand (Fig. individual compounds in M. hentscheli sponges 1). It is a 40 km long fiord-like