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Compounds from silicones alter enzyme activity in curing barnacle glue and model enzymes.

Rittschof D, Orihuela B, Harder T, Stafslien S, Chisholm B, Dickinson GH - PLoS ONE (2011)

Bottom Line: Mixtures of compounds were found on 2 commercial and 8 model silicone coatings.Activity of purified trypsin and, to a greater extent, transglutaminase was significantly altered by relevant concentrations of silicone polymer constituents.Surface-associated silicone compounds can disrupt glue curing and alter enzyme properties.

View Article: PubMed Central - PubMed

Affiliation: MSC Division, Duke University Marine Laboratory, Nicholas School of the Environment, Beaufort, North Carolina, United States of America. ritt@duke.edu

ABSTRACT

Background: Attachment strength of fouling organisms on silicone coatings is low. We hypothesized that low attachment strength on silicones is, in part, due to the interaction of surface available components with natural glues. Components could alter curing of glues through bulk changes or specifically through altered enzyme activity.

Methodology/principal findings: GC-MS analysis of silicone coatings showed surface-available siloxanes when the coatings were gently rubbed with a cotton swab for 15 seconds or given a 30 second rinse with methanol. Mixtures of compounds were found on 2 commercial and 8 model silicone coatings. The hypothesis that silicone components alter glue curing enzymes was tested with curing barnacle glue and with commercial enzymes. In our model, barnacle glue curing involves trypsin-like serine protease(s), which activate enzymes and structural proteins, and a transglutaminase which cross-links glue proteins. Transglutaminase activity was significantly altered upon exposure of curing glue from individual barnacles to silicone eluates. Activity of purified trypsin and, to a greater extent, transglutaminase was significantly altered by relevant concentrations of silicone polymer constituents.

Conclusions/significance: Surface-associated silicone compounds can disrupt glue curing and alter enzyme properties. Altered curing of natural glues has potential in fouling management.

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Related in: MedlinePlus

Gas chromatogram and tentative peak assignment (NIST database) for compounds present on Dow Corning Silastic T2® silicone.Samples were obtained by 30 second, 30 µl methanol rinses. Panels had been conditioned in flowing seawater and then used as barnacle growth substrates, immersed in seawater, for an approximate total of 1½ years before use in this analysis.
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pone-0016487-g001: Gas chromatogram and tentative peak assignment (NIST database) for compounds present on Dow Corning Silastic T2® silicone.Samples were obtained by 30 second, 30 µl methanol rinses. Panels had been conditioned in flowing seawater and then used as barnacle growth substrates, immersed in seawater, for an approximate total of 1½ years before use in this analysis.

Mentions: We used coupled gas chromatography-mass spectrometry to assess T2® and Veridian® silicones for surface-associated compounds. T2® and Veridian® had been conditioned in flowing seawater until they were not toxic to barnacle larvae, and then immersed in seawater at two month intervals as barnacle growth substrates. Each substrate was exposed to seawater for a total time of approximately 1½ years prior to their use in this study. Thirty second, 30 µl methanol rinses of these silicones contained organosiloxanes and probably cyclic siloxanes. Tentative identifications of compounds are shown in figures 1 and 2. In Silastic T2® rinses, 7 major GC peaks were identified as siloxanes (Figure 1). As shown in Figure 2, 4 major GC peaks were identified as siloxanes for Veridian®. With the exception of dimethyl flouromethyl phenylsilane, which might be derived from the catalyst, all compounds that could be identified from Veridian® rinses were also present in T2® rinses. The silicone conjugated Estra-1,3,5(10)-trien-17-one derivative, identified for both T2® and Veridian®, was not part of the original coating formulations (Coatings Industry representatives, personal communication).


Compounds from silicones alter enzyme activity in curing barnacle glue and model enzymes.

Rittschof D, Orihuela B, Harder T, Stafslien S, Chisholm B, Dickinson GH - PLoS ONE (2011)

Gas chromatogram and tentative peak assignment (NIST database) for compounds present on Dow Corning Silastic T2® silicone.Samples were obtained by 30 second, 30 µl methanol rinses. Panels had been conditioned in flowing seawater and then used as barnacle growth substrates, immersed in seawater, for an approximate total of 1½ years before use in this analysis.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3040736&req=5

pone-0016487-g001: Gas chromatogram and tentative peak assignment (NIST database) for compounds present on Dow Corning Silastic T2® silicone.Samples were obtained by 30 second, 30 µl methanol rinses. Panels had been conditioned in flowing seawater and then used as barnacle growth substrates, immersed in seawater, for an approximate total of 1½ years before use in this analysis.
Mentions: We used coupled gas chromatography-mass spectrometry to assess T2® and Veridian® silicones for surface-associated compounds. T2® and Veridian® had been conditioned in flowing seawater until they were not toxic to barnacle larvae, and then immersed in seawater at two month intervals as barnacle growth substrates. Each substrate was exposed to seawater for a total time of approximately 1½ years prior to their use in this study. Thirty second, 30 µl methanol rinses of these silicones contained organosiloxanes and probably cyclic siloxanes. Tentative identifications of compounds are shown in figures 1 and 2. In Silastic T2® rinses, 7 major GC peaks were identified as siloxanes (Figure 1). As shown in Figure 2, 4 major GC peaks were identified as siloxanes for Veridian®. With the exception of dimethyl flouromethyl phenylsilane, which might be derived from the catalyst, all compounds that could be identified from Veridian® rinses were also present in T2® rinses. The silicone conjugated Estra-1,3,5(10)-trien-17-one derivative, identified for both T2® and Veridian®, was not part of the original coating formulations (Coatings Industry representatives, personal communication).

Bottom Line: Mixtures of compounds were found on 2 commercial and 8 model silicone coatings.Activity of purified trypsin and, to a greater extent, transglutaminase was significantly altered by relevant concentrations of silicone polymer constituents.Surface-associated silicone compounds can disrupt glue curing and alter enzyme properties.

View Article: PubMed Central - PubMed

Affiliation: MSC Division, Duke University Marine Laboratory, Nicholas School of the Environment, Beaufort, North Carolina, United States of America. ritt@duke.edu

ABSTRACT

Background: Attachment strength of fouling organisms on silicone coatings is low. We hypothesized that low attachment strength on silicones is, in part, due to the interaction of surface available components with natural glues. Components could alter curing of glues through bulk changes or specifically through altered enzyme activity.

Methodology/principal findings: GC-MS analysis of silicone coatings showed surface-available siloxanes when the coatings were gently rubbed with a cotton swab for 15 seconds or given a 30 second rinse with methanol. Mixtures of compounds were found on 2 commercial and 8 model silicone coatings. The hypothesis that silicone components alter glue curing enzymes was tested with curing barnacle glue and with commercial enzymes. In our model, barnacle glue curing involves trypsin-like serine protease(s), which activate enzymes and structural proteins, and a transglutaminase which cross-links glue proteins. Transglutaminase activity was significantly altered upon exposure of curing glue from individual barnacles to silicone eluates. Activity of purified trypsin and, to a greater extent, transglutaminase was significantly altered by relevant concentrations of silicone polymer constituents.

Conclusions/significance: Surface-associated silicone compounds can disrupt glue curing and alter enzyme properties. Altered curing of natural glues has potential in fouling management.

Show MeSH
Related in: MedlinePlus