Surface bacterial community, fatty acid profile, and antifouling activity of two congeneric sponges from Hong Kong and the Bahamas

Abstract

Bacterial communities on the surfaces of 2 congeneric sponges, Mycale adhaerens from Hong Kong and M. laxissima from the Bahamas, were compared using conventional cultivation techniques and terminal restriction fragment length polymorphism (TRFLP) analysis -a cultureindependent DNA fingerprinting technique. The bacterial community on the Hong Kong sponge was more diverse, in terms of the number and type of species isolated, and different from that on the Bahamas sponge, as evident from distinct clusters formed in TRFLP analysis. Distinctive bacterial types (i.e. TRFs) were commonly found on both sponge surfaces, but none of their bacterial isolates were common. At tissue level concentration, extract of the Hong Kong sponge inhibited the growth of a wide range of bacteria isolated from the Hong Kong reference surface, but did not affect any of those isolated from the Bahamas reference surface, indicating highly specific antibacterial activity. Extracts of both sponges, when incorporated into hydrogels and exposed to the natural environment for bacterial film development, dramatically altered the bacterial community in the films, either by shifting the bacterial composition or decreasing bacterial density. Settlement assays of the resulting films using larvae of the polychaete Hydroides elegans showed that the filmed hydrogels with Hong Kong sponge extracts either inhibited larval settlement or were toxic to the larvae; however, those with the Bahamas sponge extracts had no observable effect. HPLC (high performance liquid chromatography) and GC-MS (gas chromatography-mass spectrometry) analyses revealed different chemical profiles in the extracts; the Hong Kong sponge had a more diverse fatty acid profile. Our results suggest that the 2 congeneric sponges from geographically separated regions have 'speciesspecific', surface-associated bacterial communities and antifouling activities, which might be due to the differences in the chemical and fatty acid compositions of the 2 sponges. Alternately, different sponge-associated bacterial communities may reflect habitat differences in sympatric bacterial and fouling communities.

Chemical defense against predators and bacterial fouling in the Mediterranean sponges Axinella polypoides and A. verrucosa

“…The bacterial settlement field assay was adapted from similar methods described by Henrikson & Pawlik (1995), Harder et al (2004), Dobretsov et al (2005a,b), and Lee et al (2007). Extracts were re-dissolved by gentle sonication using methanol for n-butanol and Et 2 O for Et 2 O partitions to give 10-fold natural concentrations.…”

“…Tsoukatou et al 2002, Dobretsov et al 2005a,b, Lee et al 2007, Qian et al 2010. One of the first steps in the fouling process is bacterial settlement and the establishment of a biofilm, which can influence the later settlement of macrofouling organisms such as barnacles and polychaetes (Sjögren et al 2004, Lau et al 2005, Lee et al 2007). Modulation or prevention of bacterial settlement is therefore a likely target for the sponge's antifouling compounds (Kubanek et al 2002, Kelly et al 2003, Lee et al 2007.…”

“…One of the first steps in the fouling process is bacterial settlement and the establishment of a biofilm, which can influence the later settlement of macrofouling organisms such as barnacles and polychaetes (Sjögren et al 2004, Lau et al 2005, Lee et al 2007). Modulation or prevention of bacterial settlement is therefore a likely target for the sponge's antifouling compounds (Kubanek et al 2002, Kelly et al 2003, Lee et al 2007. Organic extracts and pure compounds from several sponges have been shown to inhibit settlement and growth of environmental bacteria (e.g.…”

Pyrosequencing reveals highly diverse and species-specific microbial communities in sponges from the Red Sea

“…These studies suggest a stable and specific relationship between sponges and bacteria. However, debate on the stability and specificity of sponge-microbe association arises because of contradictory results showing variations in bacterial communities associated with sponges from different genera, locations or time scale (Qian et al, 2006;Wichels et al, 2006;Lee et al, 2007). In a more recent study, Lee et al (2009b) demonstrated that consistent bacterial communities only hold for certain species of sponges.…”

Chemical antifouling defences of sea stars: effects of the natural products hexadecanoic acid, cholesterol, lathosterol and sitosterol

“…Furthermore, crude extracts of the sponge Crella incrustans and cholesterol controls had a negative effect on the settlement of larvae of the ascidian Podoclavella moluccensis (Davis et al 1991). Finally, Lee et al (2007) suggested that the species-specific, surface-associated bacterial communities and antifouling activities of the congeneric sponges Mycale adhaerens from Hong Kong and Mycale laxissima from the Bahamas might result from the differences in the fatty acid profiles of these sponges. Mycale adhaerens has a more diverse fatty acid profile, in terms of the type and relative abundance of fatty acids detected, than M. laxissima (Lee et al 2007).…”