Publication Date

Fall 2011

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Advisor

Sabine Rech

Keywords

Acorn Worms, Bacillus, FADH2-dependent halogenases, Halogenation, Haloperoxidases, organohalogens

Subject Areas

Biology; Microbiology; Molecular biology

Abstract

Organohalogens have diverse biological functions in the environment. Marine acorn worms produce brominated products that may act as antifoulants, chemical deterrents, and substrates in bioluminescence reactions. Haloperoxidases purified from the homogenates of acorn worms synthesize bromophenols. Commensal or mutualistic bacteria living on the worms may produce halogenation enzymes that brominate organics.

The genomic DNA of 48 bacterial isolates from the surface of the red-banded acorn worm, Ptychodera jamaicensis, was extracted and screened for bromoperoxidase and FADH2-dependent halogenase genes. A 16S rDNA phylogenetic tree showed that the isolates were gram-positive bacteria and included 36 Firmicutes and 12 Actinobacteria. Nineteen isolates had a 700 base-pair bromoperoxidase gene, and two isolates had a 1,000 base-pair FADH2-dependent halogenase gene.

Eight of the 19 isolates positive for the bromoperoxidase gene were tested for bromoperoxidase activity with a phenol red and monochlorodimedone assay. One isolate had the bromoperoxidase gene and bromoperoxidase activity of 0.417 in the monochlorodimedone assay. It is possible that bacteria on the red-banded acorn worm synthesize bromoperoxidases, which produce bromophenols. These bacteria may synthesize these compounds as antimicrobials towards gram-negative bacteria.

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