| 1. |
- Arnebrant, Thomas, et al.
(författare)
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Lubricating Properties of the Initial Salivary Pellicle
- 2003
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Ingår i: Biofouling (Print). - : Harwood Academic Publishers. - 0892-7014 .- 1029-2454. ; 19:6, s. 365-369
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Tidskriftsartikel (refereegranskat)abstract
- The role of saliva in the oral cavity is manifold; an important function is to serve as lubricant between hard (enamel) and soft (mucosal) tissues. Intraoral lubrication is of crucial importance in order to maintain functions such as deglutition, mastication and the faculty of speech. A large number of people suffer from impaired salivary functions, displaying symptoms such as 'dry mouth'. This results in a need for methods to assess the lubricating properties of both native saliva and potential artificial saliva formulations. Here, normal as well as lateral forces, acting between adsorbed salivary films, have been measured for the first time by means of colloidal probe atomic force microscopy (AFM). It was found that the presence of salivary pellicles between hard surfaces reduces the friction coefficient by a factor of 20. This reduction of friction is consistent with the long-range purely repulsive nature of the normal forces acting between the salivary films. The lubricating mechanism is presumably based on a full separation of the sliding surfaces by the salivary films. The friction between salivary films has been investigated at normal loads that cover the clinical jaw closing forces, and it can be concluded that the lubricating properties are maintained within this load interval. The present study indicates the usefulness of colloidal probe AFM, which offers a direct and quantitative measure of lubrication at a molecular level, in the study of biotribological phenomena. In particular, the results obtained here may have implications for the development of saliva substitutes.
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| 2. |
- Arvidsson, Anna, 1973, et al.
(författare)
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Characterisation of structures in salivary secretion film formation. An experimental study with atomic force microscopy
- 2004
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Ingår i: Biofouling. - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 20:3, s. 181-8
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the present study was to characterise the structure dynamics of pure salivary secretions retained on controlled surfaces with different surface energies in the early stage of salivary film formation. Germanium prisms prepared to have either low surface energy or medium surface energy were incubated in fresh secretions of either human parotid saliva (HPS) or human submandibular/sublingual saliva (HSMSLS) for 15, 90, and 180 min. After controlled rinsing with distilled water, the surfaces were air dried and thereafter imaged with atomic force microscopy (AFM). The amount of adsorbed material and the size of the structures detected increased with increased saliva exposure time. The film thicknesses varied from 10 to 150 nm, and both HPS and HSMSLS films contained structures with diameters varying from 40 nm to 2 microm. Some of these were clustered into special formations. The HPS films exhibited a more granular morphology than the HSMSLS films. Furthermore, branched lines were detected on the low surface energy germanium prisms incubated in saliva. The results indicate that exposure time, surface energy, and type of salivary secretion all are factors affecting the adsorption characteristics of salivary films.
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| 3. |
- Berg, I. C. H., et al.
(författare)
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Lubricating properties of the initial salivary pellicle - an AFM Study
- 2003
-
Ingår i: Biofouling (Print). - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 19:6, s. 365-369
-
Tidskriftsartikel (refereegranskat)abstract
- The role of saliva in the oral cavity is manifold; an important function is to serve as lubricant between hard (enamel) and soft (mucosal) tissues. Intraoral lubrication is of crucial importance in order to maintain functions such as deglutition, mastication and the faculty of speech. A large number of people suffer from impaired salivary functions, displaying symptoms such as 'dry mouth'. This results in a need for methods to assess the lubricating properties of both native saliva and potential artificial saliva formulations. Here, normal as well as lateral forces, acting between adsorbed salivary films, have been measured for the first time by means of colloidal probe atomic force microscopy (AFM). It was found that the presence of salivary pellicles between hard surfaces reduces the friction coefficient by a factor of 20. This reduction of friction is consistent with the long-range purely repulsive nature of the normal forces acting between the salivary films. The lubricating mechanism is presumably based on a full separation of the sliding surfaces by the salivary films. The friction between salivary films has been investigated at normal loads that cover the clinical jaw closing forces, and it can be concluded that the lubricating properties are maintained within this load interval. The present study indicates the usefulness of colloidal probe AFM, which offers a direct and quantitative measure of lubrication at a molecular level, in the study of biotribological phenomena. In particular, the results obtained here may have implications for the development of saliva substitutes.
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| 4. |
- Granhag, Lena, 1974, et al.
(författare)
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Roughness-dependent removal of settled spores of the green alga Ulva (syn. Enteromorpha) exposed to hydrodynamic forces from a water jet
- 2004
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Ingår i: Biofouling. - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 20:2, s. 117-122
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Tidskriftsartikel (refereegranskat)abstract
- Topographic features change the hydrodynamic regime over surfaces subjected to flow. Hydrodynamic microenvironments around topographic structures may have consequences for recruitment and removal of propagules of marine benthic organisms. The settlement and adhesion of zoospores from the green alga Ulva linza (syn. Enteromorpha linza) to defined topographies was investigated. A range of topographic size scales (R-z: 25-100 mum) was manufactured from plankton nets, creating patterns with ridges and depressions. The topographic scales span a roughness similar to that of natural substrata and antifouling coatings. Spores were removed from the surfaces by a calibrated water jet. Fewer spores were removed from the smallest topographic structure tested (R-z: 25 mum) compared to both the smooth (R-z: 1) and the roughest (R-z: 100 mum) structures. Zoospores that settled in depressions were less likely to be removed compared to spores on the ridges. The results in terms of the interaction between surface topography and hydrodynamic forces have implications for both natural substrata exposed to wave action and antifouling surfaces on ships' hulls. The possible effects of topography on increasing zoospore adhesion and offering a refuge from hydrodynamic forces are discussed.
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| 5. |
- Hahn Berg, Cecilia I, et al.
(författare)
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Intraoral Lubrication of PRP-1, Statherin and Mucin as Studied by AFM
- 2004
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Ingår i: Biofouling (Print). - : Taylor & Francis. - 0892-7014 .- 1029-2454. ; 20:1, s. 65-70
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this paper was to elucidate the mechanisms behind salivary lubrication with special emphasis on the lubricity of three key components of the pellicle, viz human acidic proline-rich protein 1 (PRP-1), human statherin and bovine submaxillary mucin (BSM). The lubricating properties of the proteins have been assessed by means of colloidal probe atomic force microscopy, and are discussed in relation to their adsorption behaviour. To various extents, the proteins investigated all showed a lubricating effect when adsorbed to silica surfaces. For comparable concentrations, PRP-1 was found to have a more pronounced lubricating effect than BSM, which in turn showed a higher lubricity than statherin. The relative lubricity is in accordance with previously reported relative adsorbed amounts of the three proteins, within the investigated concentration interval. It is concluded that PRP-1 has the highest lubricating capacity as a pure fraction among the preparations investigated, and that the lubricating effect of PRP-1 as a pure fraction is notably large as compared to the lubricity of human whole saliva.
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| 6. |
- Hahn Berg, IC, et al.
(författare)
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Intraoral lubrication of PRP-1, statherin and mucin as studied by AFM
- 2004
-
Ingår i: Biofouling (Print). - 0892-7014 .- 1029-2454. ; 20, s. 65-70
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this paper was to elucidate the mechanisms behind salivary lubrication with special emphasis on the lubricity of three pellicle key components (human acidic proline-rich protein 1 (PRP-1), human statherin and bovine submaxillary mucin (BSM)). The lubricating properties of the proteins have been assessed by means of colloidal probe atomic force microscopy, and are discussed in relation to their adsorption behavior. To various extent, the investigated proteins all showed a lubricating effect when adsorbed to silica surfaces. For comparable concentrations, PRP-1 was found to have a more pronounced lubricating effect than BSM, which in turn showed a higher lubricity than statherin. The relative lubricity is in accordance with previously reported relative adsorbed amounts of the three proteins, within the investigated concentration interval. We conclude that PRP-1 has the highest lubricating capacity as a pure fraction among the investigated preparations, and that the lubricating effect of PRP-1 as a pure fraction is notably large as compared to the lubricity of human whole saliva
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| 7. |
- Hahn Berg, IC, et al.
(författare)
-
Lubricating properties of the initial salivary pellicle – an AFM study
- 2003
-
Ingår i: Biofouling (Print). - 0892-7014 .- 1029-2454. ; 19, s. 365-369
-
Tidskriftsartikel (refereegranskat)abstract
- The role of saliva in the oral cavity is manifold; an important function is to serve as lubricant between hard (enamel) and soft (mucosal) tissues. Intraoral lubrication is of crucial importance in order to maintain functions such as deglutition, mastication and the faculty of speech. A large number of people suffer from impaired salivary functions, displaying symptoms such as 'dry mouth'. This results in a need for methods to assess the lubricating properties of both native saliva as well as potential artificial saliva formulations. Here we measure normal as well as lateral forces, acting between adsorbed salivary films, for the first time by means of colloidal probe atomic force microscopy. We find that the presence of salivary pellicles between hard surfaces reduces the friction coefficient by a factor of 20. This reduction of friction is consistent with the long-range purely repulsive nature of the normal forces acting between the salivary films. The lubricating mechanism is presumably based on a full separation of the sliding surfaces by the salivary films. The friction between salivary films has been investigated at normal loads that well cover the clinical jaw closing forces, and it can be concluded that the lubricating properties are maintained within this load interval. The present study indicates the usefulness of colloidal probe atomic force microscopy, which offers a direct and quantitative measure of the lubrication on a molecular level, in the study of biotribological phenomena. In particular, the results obtained here may have implications for the development of saliva substitutes
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| 8. |
- Hahn Berg, IC, et al.
(författare)
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Salivary protein adsorption onto hydroxyapatite and SDS-mediated elution studied by in situ ellipsometry
- 2001
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Ingår i: Biofouling (Print). - 0892-7014 .- 1029-2454. ; 17, s. 173-187
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Tidskriftsartikel (refereegranskat)abstract
- Whole unstimulated saliva from two donors was investigated both with respect to adsorption characteristics and SDS-induced elutability. Salivary protein adsorption onto hydroxyapatite (HA) discs was studied by means of in situ ellipsometry in the concentration range 0.1-20% saliva. The adsorbed amounts on HA were found to be similar to those on silica, but the rates of adsorption were lower. Protein adsorption was virtually unaffected by the presence of Na+, whereas Ca2+ induced nucleation of calcium phosphate at the surface, the deposition rate being influenced by the pellicle age but not by the presence of saliva in bulk solution. The SDS elutability of adsorbed pellicles was determined on HA as well as on silica surfaces. Desorption from both surfaces was found to occur in the same SDS concentration range, although a residual layer was observed on HA. The slight net positive charge and lower charge density of HA as compared to the strongly negatively charged silica, may, at least partly, account for this observation by causing a reduction in the repulsive force between protein-surfactant complexes and the surface. Interindividual differences, observed in the adsorption as well as elution experiments, are thought to relate to the compositional differences observed by SDS-PAGE
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| 9. |
- Head, R. M., et al.
(författare)
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Gregarious settlement in cypris larvae: The effects of cyprid age and assay duration
- 2004
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Ingår i: Biofouling. - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 20:2, s. 123-128
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Tidskriftsartikel (refereegranskat)abstract
- Gregarious behaviour of marine larvae is perhaps most clearly associated with finding a suitable habitat in a changeable or restricted environment, or with finding other conspecifics with which to mate. Prior work has shown that in settlement assays using cypris larvae of the barnacle Balanus amphitrite , gregarious interactions significantly affected the interpretation of experiments testing the activity of organic settlement promoters and inhibitors. Other studies have also shown effects of cyprid age and pheromone concentration on settlement behaviour. However, the effects of interactions between gregariousness and these two factors are not known. The aim of this study was to test the hypotheses that i) as cyprids age the effects of gregariousness become less apparent, and ii) as the duration of the experiment increases gregarious effects become more apparent, using cypris larvae of B. amphitrite and Balanus improvisus . Three age classes of cyprids were used at six densities in a fully factorial design. For B. improvisus cyprids significant gregarious effects occurred between 3 or more larvae, and although larval age and experiment duration had significant main effects, there were no interactions between these important factors and gregariousness. For B. amphitrite cyprids significant gregarious effects also occurred with greater than or equal to3 larvae per well, though this effect was strongly dependent upon experiment duration. B. amphitrite cyprid sensitivity to conspecific cues does not change with age, although increasing experiment duration and age interact to increase settlement. Differences between species may be due to different thresholds to conspecific larval cues, or B. improvisus cyprids release much more larval temporary adhesive during exploration.
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| 10. |
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| 11. |
- Lindh, Liselott, et al.
(författare)
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An in vitro study of initial adsorption from human parotid and submandibular/sublingual resting saliva at solid/liquid interfaces
- 2001
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Ingår i: Biofouling (Print). - : Taylor and Francis. - 0892-7014 .- 1029-2454. ; 17:3, s. 227-239
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Tidskriftsartikel (refereegranskat)abstract
- The influence of saliva concentration, saliva total protein content and the wetting characteristics of exposed solids on in vitro film formation was studied by the technique of in situ ellipsometry. The rates and plateau values of adsorption (45 min) at solid/liquid interfaces (hydrophilic silica and hydrophobic methylated silica surfaces) were determinated for human parotid (HPS) and submandibular/sublingual (HSMSLS) resting saliva solutions (0.1 and 1.0%, (v/v), saliva in phosphate buffered saline). Adsorption rates were related to a model assuming mass transport through an unstirred layer adjacent to the surface. The results showed that the adsorption was rapid, concentration dependent and higher on hydrophobic than on hydrophilic surfaces. Analysis of the influence of protein concentration on the adsorbed amounts demonstrated an interaction between protein concentration and the two surfaces for HPS and HSMSLS, respectively. This may indicate differences in binding mode. Inter-individual differences were found not to be significant at the 1% level of probability. Comparison of the observed adsorption and calculated diffusion rates suggest that on hydrophilic surfaces initial adsorption of proteins diffusing at rates corresponding to those of statherin and aPRPs takes place, whereas on hydrophobic surfaces lower molecular mass compounds appear to be involved.
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| 12. |
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| 13. |
- Lindh, Liselott, et al.
(författare)
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On the adsorption of human proline-rich proteins (PRP-1 and PRP-3) and statherin at solid/liquid interfaces
- 2002
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Ingår i: Biofouling (Print). - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 18:2, s. 87-94
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Tidskriftsartikel (refereegranskat)abstract
- The objective of the present study was to investigate the adsorption of PRP-1, PRP-3 and statherin to solid surfaces in terms of dependence on concentration, the presence of electrolyte and surface wettability. Time resolved in situ ellipsometry was used to determine the adsorbed amounts and adsorption rates of pure PRP-1, PRP-3 and statherin onto pure (hydrophilic) and methylated (hydrophobized) silica surfaces. The initial film build-up was fast and plateaus were reached within 10 min at all concentrations for both types of surfaces and all proteins. The observed adsorption and calculated diffusion rates of PRP-1, PRP-3 and statherin, respectively, indicated that the initial adsorption was mass transport controlled at low concentrations. At hydrophobic surfaces, isotherm shapes and adsorbed amounts were similar for PRP-1 and PRP-3, while statherin adsorbed to a higher extent. At hydrophilic surfaces only PRP-1 adsorbed substantially, while for PRP-3 and statherin adsorbed amounts were low. The presence of Ca 2+ ions in the phosphate buffer solution increased the adsorption of statherin and PRP-3 on hydrophobic surfaces, while PRP-1 was unaffected. On hydrophilic surfaces, all three proteins adsorbed in higher amounts in NaCl, compared to CaCl 2 at similar ionic strength. It is concluded that acidic PRPs (PRP-1 and PRP-3) and statherin readily form films on a variety of materials and solution conditions, showing that their functions may be fulfilled under a wide range of conditions.
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| 14. |
- Sjögren, Martin, et al.
(författare)
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Recruitment in the field of Balanus improvisus and Mytilus edulis in response to the antifouling cyclopeptides barettin and 8,9-dihydrobarettin from the marine sponge Geodia barretti
- 2004
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Ingår i: Biofouling. - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 20:6, s. 291-297
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Tidskriftsartikel (refereegranskat)abstract
- In this field investigation the two cyclopeptides, isolated from the marine sponge Geodia barretti Bowerbank (Geodiidae, Astrophorida), are shown to be very efficient in preventing recruitment of the barnacle Balanus improvisus (Cirripedia, Crustacea) and the blue mussel Mytilis edulis (Protobranchia, Lamellibranchia) when included in different marine paints. These brominated cyclopeptides, named barettin and 8,9-dihydrobarettin were incorporated in different non-toxic coatings. The substances were used in the concentrations 0.1 and 0.01% in all treatments. The most efficient paint was a SPC polymer. This paint, in combination with barettin and 8,9-dihydrobarettin, reduced the recruitment of B. improvisus by 89% (barettin, 0.1%) and by 67% (8,9-dihydrobarettin, 0.1%) as compared to control panels. For M. edulis, the reduction of recruitment was 81% with barettin (0.1%) and 72% with 8,9-dihydrobarettin (0.1%) included in the SPC paint. This indicates that the two compounds from G. barretti could provide non-toxic alternatives as additives in antifouling paints, since the heavy metal-based marine paints are to be replaced.
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| 15. |
- Sott, Kristin, 1974, et al.
(författare)
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Adsorption behavior and enzymatically or chemically induced cross-linking of a mussel adhesive protein
- 2000
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Ingår i: Biofouling. - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 16:2-4, s. 119-132
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption behavior of the mussel adhesive protein Mytilus edulis foot protein-1 (Mefp-1) has been investigated on a negatively charged polar SiO2 surface and an electrically inert non-polar CH3-terminated thiolated gold surface. How the structure of adsorbed Mefp-1 is changed upon chemically and enzymatically induced cross-linking using sodium periodate (NaIO4) and catechol oxidase, both of which transform DOPA residues in Mefp-1 into highly reactive o-quinones, was also investigated. The results are compared with those resulting from addition of Cu2+ to adsorbed Mefp-1, which forms complexes with and catalyses oxidation of DOPA residues, previously suggested to participate in the cohesive and adhesive properties of the byssus thread of M. edulis. By combining surface plasmon resonance (SPR) and quartz crystal microbalance/dissipation (QCM-D) measurements, the effects of these agents were investigated with respect to changes in the amount of coupled water, the viscoelastic properties (rigidity) and the hydrodynamic thickness of the protein adlayers. The layer of Mefp-1 formed on the bare CH3-terminated surface was elongated, flexible and coupled hydrodynamically a substantial amount of water, whereas Mefp-1 formed a rigidly attached adlayer on the SiO2 surface. Upon enzymatically and chemically induced cross-linking of Mefp-1 formed on the CH3 surface, the rigidity of the adlayer(s) increased significantly. A similar increase in the rigidity was observed also upon addition of Cu2+, suggesting that the high level of metal ions present in the byssus thread might be essential for the cohesive and adhesive properties of this protein. For the mass-uptake kinetics of enzymatically induced cross-linking, three different phases were observed and are interpreted as competition between binding of protein and release of coupled water. For the reaction with NaIO4 and Cu2+ only release of water affected the coupled mass. The importance of this type of information for an improved understanding of the strong adhesion and cohesive properties in marine environments is discussed.
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| 16. |
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| 17. |
- Berntsson, Kent M., 1963, et al.
(författare)
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Temporal and spatial patterns in recruitment and succession of a temperate marine fouling assemblage: A comparison of static panels and boat hulls during the boating season
- 2003
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Ingår i: Biofouling. - 0892-7014. ; 19:3, s. 187-195
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Tidskriftsartikel (refereegranskat)abstract
- Protection against biofouling is essential for efficient operation of boats and ships. Restrictions on the use of traditional, toxic antifouling coatings call for new less toxic methods. Future antifouling strategies will likely be based on more specific action against dominant foulers and will require more detailed information about spatial and temporal differences in fouling communities on artificial substrates. In this study, the recruitment and succession of fouling organisms was examined on artificial (PMMA) panels exposed to natural flow speeds on the Skagerrak coast (Sweden). The recruitment of foulers on static panels was then compared to fouling allowed to develop on boat hulls in surveys of new non-toxic coatings. The temporal and spatial variation in recruitment was examined on a monthly interval within the boating season, from May-September. Furthermore, the succession of the fouling community was examined during the same interval. A total of 12 sessile invertebrate species was recorded on the static panels with dominant foulers being the barnacle Balanus improvisus (July-September) and the mussel Mytilus edulis (June-August). The mean abundance during peak settlement on panels after 1 month's deployment was 370+/-134 individuals dm(-2) for B. improvisus and 340+/-415 individuals dm(-2) for M. edulis . The succession of foulers on the panels led to a dominance of M. edulis (maximum of 7470+/-2830 individuals dm(-2) ) over B. improvisus (maximum of 2295+/-680 individuals dm(-2) ). This was in contrast to the fouling development on boat hulls, examined after 4 months exposure in 3 successive years, where B. improvisus was the dominant species (mean abundance 222+/-104 and maximum 713+/-527 individuals dm(-2) ). Some boats were covered to an extent of almost 100% by B. improvisus with only a few M. edulis (mean abundance 20+/-16). The biomass of fouling on boat hulls varied from average dry weights of 1.3+/-1 to 13+/-5 g dm(-2) . These results show that extrapolation from static panels (common in evaluation of antifouling performance) to fouling on boat hulls may be problematic.
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| 18. |
- Burgess, J. G., et al.
(författare)
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The development of a marine natural product-based antifouling paint
- 2003
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Ingår i: Biofouling. - 0892-7014. ; 19, s. 197-205
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Tidskriftsartikel (refereegranskat)abstract
- Problems with tin and copper antifouling compounds have highlighted the need to develop new environmentally friendly antifouling coatings. Bacteria isolated from living surfaces in the marine environment are a promising source of natural antifouling compounds. Four isolates were used to produce extracts that were formulated into ten water-based paints. All but one of the paints showed activity against a test panel of fouling bacteria. Five of the paints were further tested for their ability to inhibit the settlement of barnacle larvae, Balanus amphitrite, and algal spores of Ulva lactuca, and for their ability to inhibit the growth of U. lactuca. Two paints caused a significant decrease in the number of settled barnacles. One paint containing extract of Pseudomonas sp. strain NUDMB50-11, showed excellent activity in all assays. The antifouling chemicals responsible for the activity of the extract were isolated, using bioassay guided fractionation, and their chemical structures determined.
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