Meeting Abstract

62.1  Tuesday, Jan. 6  Identifying genes from a marine bacterium that are involved in metamorphic induction of the tube worm Hydroides elegans HUANG, Ying*; HADFIELD, Michael G; Univ. of Hawaii at Manoa; Univ. of Hawaii at Manoa yinghuan@hawaii.edu

The marine tube worm Hydroides elegans provides an excellent model for laboratory studies of invertebrate metamorphosis. Competent larvae of H. elegans are induced to settle and metamorphose by single- or multiple-species bacterial biofilms. A marine bacterium, Pseudoalteromonas luteoviolacea, isolated from a seawater-aquarium biofilm in our lab, has been shown to strongly induce settlement of competent larvae of H. elegans. However, the factors in bacterial biofilms that induce settlement and metamorphosis of these larvae are unknown. To determine the nature of these factors, transposon mutagenesis was applied to P. luteroviolacea to identify genes that are involved in inducing metamorphosis of H. elegans. Using a mini transposon, Tn10, a piece of foreign DNA was randomly inserted into the chromosome of P. luteroviolacea to create a mutant library. This insertion was expected to disrupt the function of genes into which it is incorporated. Two strains which are deficient in their inductive ability were isolated from the mutant library. By sequencing genes flanking the transposon, two genes whose expression is necessary to metamorphic induction of H. elegans were isolated and partially sequenced (on going). Recombined mutants, prepared for both gene loci, lost their inductive capacity for larvae of H. elegans, strongly suggesting that both of the isolated genes are essential for metamorphic induction. Understanding the structures and products of these two genes will help us to understand the mechanisms by which biofilms influence settlement and metamorphosis of marine invertebrate larvae.