title: Isolation of bacterial metabolites as natural inducers for larval settlement in the marine polychaete Hydroides elegans (Haswell).
abstract: The bacterial component of marine biofilms plays an important role in the induction of larval settlement in the polychaete Hydroides elegans. In this study, we provide experimental evidence that bacterial metabolites comprise the chemical signal for larval settlement. Bacteria were isolated from biofilms, purified and cultured according to standard procedures. Bacterial metabolites were isolated from spent culture broth by chloroform extraction as well as by closed-loop stripping and adsorption of volatile components on surface-modified silica gel. A pronounced biological activity was exclusively observed when concentrated metabolites were adsorbed on activated charcoal. Larvae did not respond to waterbome metabolites when prevented from contacting the bacterial film surface. These results indicate that an association of the chemical signal with a sorbent-like substratum may be an essential cofactor for the expression of biological activity. The functional role of bacterial exopolymers as an adsorptive matrix for larval settlement signals is discussed.
authors.affiliation: Hong Kong University of Science and Technology, Department of Biology, Clear Water Bay, Kowloon, SAR.
authors.forename: Tilmann
authors.initials: T
authors.lastname: Harder
authors.forename: Stanley Chun Kwan
authors.initials: SC
authors.lastname: Lau
authors.forename: Hans-Uwe
authors.initials: HU
authors.lastname: Dahms
authors.forename: Pei-Yuan
authors.initials: PY
authors.lastname: Qian
mesh_terms: D000818:Animals; D001419:Bacteria / Q000737:chemistry*; D018441:Biofilms; D007814:Larva; D009068:Movement; D009949:Orientation; D010675:Pheromones / Q000494:pharmacology*; D011077:Polychaeta; D011108:Polymers; D014835:Volatilization
chemical_list: D010675:Pheromones; D011108:Polymers