Assessment of marine biofilm attachment and growth for antifouling surfaces under static and controlled hydrodynamic con
- PDF / 611,662 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 70 Downloads / 164 Views
Assessment of marine biofilm attachment and growth for antifouling surfaces under static and controlled hydrodynamic conditions Maria Salta1, Julian A. Wharton1, Paul Stoodley1, Robert J.K. Wood1, Keith R. Stokes1,2. 1
national Centre for Advanced Tribology at Southampton (nCATS), School of Engineering Sciences, University of Southampton, Highfield, Southampton, SO17 1BJ, UK. 2 Physical Sciences Department, Dstl, Porton Down, Salisbury, Wiltshire, SP4 0JQ, UK. ABSTRACT This investigation has assessed natural product antifouling performance of an isolated compound from a terrestrial source against marine biofilm forming bacteria, Cobetia marina and Marinobacter hydrocarbonoclasticus. Novel bioassay protocols using the hydrodynamic system and its well plate microfluidics capability were developed to test the in situ antifouling efficacy of the natural product against biofilm attachment under two shear stresses (0.07 and 0.3 Pa). The hydrodynamic results allowed for the first time the direct observation of the natural product influence on newly attached marine biofilms and the evolution of the antifouling affect with time. Biofilm attachment behaviour appeared to be markedly different in the presence of the natural product, illustrated by limited cluster and extracellular polymeric substance formation which suggests an interference of the bacterial attachment mechanisms. Ultimately, this is fundamental in developing greater understanding of the biofilm kinetics. These observations were confirmed using epifluoresence and confocal microscopy, with the additional corroborative data on bacterial cell integrity using the LIVE / DEAD nucleic acid kit. INTRODUCTION Marine biofouling is the accumulation of organisms on underwater surfaces of ships, causing increased hydrodynamic drag, resulting in higher fuel consumption and decreased speed and range of the vessel. Biofilms constitute a major component of the overall biofouling, for example, a 14 % increase in ship fuel cost resulting from marine biofilms. Past solutions to antifouling (AF) have used toxic coatings which have subsequently been shown to severely affect marine life. The prohibited use of these antifoulants has led to the search for bio-inspired AF strategies [1]. Current approaches towards the production of alternative coatings include the incorporation of natural AF compounds into paints. Significant effort has previously been directed towards more environmentally benign strategies, however, ultimately a combination of surface features and chemistry will lead to greater AF performance. Screening assays for novel AF compounds are often separated into two categories; toxicity and AF assays. Increasingly there is evidence that active compounds affect organisms at non-toxic concentrations [2], hence, the necessity for more insightful AF testing directly on surfaces for both static and hydrodynamic conditions. This study assessed natural product AF performance of an isolated compound from a terrestrial source – a quinone derivative compound (QDC) – against biofilm
Data Loading...
