| 1. |
- Abramova, Anna, 1990, et al.
(författare)
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The complex barnacle perfume: identification of waterborne pheromone homologues in Balanus improvisus and their differential expression during settlement
- 2019
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Ingår i: Biofouling. - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 35:4, s. 416-428
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Tidskriftsartikel (refereegranskat)abstract
- A key question in barnacle biology is the nature of cues that induce gregarious settlement. One of the characterised cues is the waterborne settlement pheromone (WSP). This study aimed to identify WSP homologues in Balanus improvisus and to investigate their expression during settlement. Six WSP homologues were identified, all containing an N-terminal signal peptide, a conserved core region, and a variable C-terminus comprising several -GR- and -HDDH- motifs. The B. improvisus WSP homologues were expressed in all settlement stages but showed different expression patterns. The homologue most similar to the B. amphitrite WSP was the most abundant and was constantly expressed during settlement. In contrast, several of the other WSP homologues showed the greatest expression in the juvenile stage. The presence of several WSP homologues suggests the existence of a pheromone mix, where con-specificity might be determined by a combination of sequence characteristics and the concentration of the individual components.
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| 2. |
- Al-Fori, M., et al.
(författare)
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Antifouling properties of zinc oxide nanorod coatings
- 2014
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Ingår i: Biofouling. - : Taylor & Francis. - 0892-7014 .- 1029-2454. ; 30:7, s. 871-882
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Tidskriftsartikel (refereegranskat)abstract
- In laboratory experiments, the antifouling (AF) properties of zinc oxide (ZnO) nanorod coatings were investigated using the marine bacterium Acinetobacter sp. AZ4C, larvae of the bryozoan Bugula neritina and the microalga Tetraselmis sp. ZnO nanorod coatings were fabricated on microscope glass substrata by a simple hydrothermal technique using two different molar concentrations (5 and 10 mM) of zinc precursors. These coatings were tested for 5 h under artificial sunlight (1060 W m(-2) or 530 W m(-2)) and in the dark (no irradiation). In the presence of light, both the ZnO nanorod coatings significantly reduced the density of Acinetobacter sp. AZ4C and Tetraselmis sp. in comparison to the control (microscope glass substratum without a ZnO coating). High mortality and low settlement of B. neritina larvae was observed on ZnO nanorod coatings subjected to light irradiation. In darkness, neither mortality nor enhanced settlement of larvae was observed. Larvae of B. neritina were not affected by Zn2+ ions. The AF effect of the ZnO nanorod coatings was thus attributed to the reactive oxygen species (ROS) produced by photocatalysis. It was concluded that ZnO nanorod coatings effectively prevented marine micro and macrofouling in static conditions.
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| 3. |
- Andersson, Annika, et al.
(författare)
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Adhesion and removal of dormant, heat-activated, and germinated spores of three strains of Bacillus cereus
- 1998
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Ingår i: Biofouling (Print). - 0892-7014 .- 1029-2454. ; 13:1, s. 51-67
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Tidskriftsartikel (refereegranskat)abstract
- As the spores of Bacillus cereus are known to be very adhesive, the cleaning processes used to eliminate them are often inefficient. This study investigated how adhesion and removal of spores varied among strains of the species B. cereus. The adhesion and removal of spores during their life cycle were also examined. Spores of three different strains of B. cereus, viz. NVH 61, 1AM 1110 and NCTC 2599, were used. IAM 1110 spores adhered in greater numbers than spores of the other two strains and were the most hydrophobic; four times as many spores of this strain adhered than of the least adhesive spores, NCTC 2599. Spores of both these strains have an exosporium and appendages, but as the relative hydrophobicity varies, there are probably differences in their chemical composition. It was also found that dormant spores were 33-48% more adhesive than germinated spores. There were no obvious differences in adhesion between dormant and heat-activated spores. Up to 80% of the germinated spores could be removed from the surfaces tested. Dormant and heat-activated spores on the other hand were difficult to remove from the surfaces. When siliconized glass surfaces were coated with milk, germinated spores were still the easiest to remove but the difference was not as marked as before. Therefore, this work suggests that cleaning processes should take into consideration factors that boost spore germination in order to improve the cleaning.
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| 4. |
- 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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| 5. |
- Aroonsang, Watcharapong, et al.
(författare)
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Influence of substratum hydrophobicity on salivary pellicles : organization or composition?
- 2014
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Ingår i: Biofouling (Print). - : Taylor & Francis. - 0892-7014 .- 1029-2454. ; 30:9, s. 1123-1132
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Tidskriftsartikel (refereegranskat)abstract
- Different physico-chemical properties (eg adsorption kinetics, thickness, viscoelasticity, and mechanical stability) of adsorbed salivary pellicles depend on different factors, including the properties (eg charge, roughness, wettability, and surface chemistry) of the substratum. Whether these differences in the physico-chemical properties are a result of differences in the composition or in the organization of the pellicles is not known. In this work, the influence of substratum wettability on the composition of the pellicle was studied. For this purpose, pellicles eluted from substrata of different but well-characterized wettabilities were examined by means of sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The results showed that substratum hydrophobicity did not have a major impact on pellicle composition. In all substrata, the major pellicle components were found to be cystatins, amylases and large glycoproteins, presumably mucins. In turn, interpretation of previously reported data based on the present results suggests that variations in substratum wettability mostly affect the organization of the pellicle components.
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| 6. |
- 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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| 7. |
- Bellas, Juan, et al.
(författare)
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Sublethal effects of a new antifouling candidate on lumpfish (Cyclopterus lumpus L.) and Atlantic cod (Gadus morhua L.) larvae
- 2005
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Ingår i: Biofouling. - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 21:3-4, s. 207-216
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Tidskriftsartikel (refereegranskat)abstract
- Sublethal effects of medetomidine, a new generation antifouling compound, on lumpfish ( Cyclopterus lumpus L.) and cod ( Gadus morhua L.) larvae were examined. The effects on respiration rate and on colour adaptation of newly hatched larvae were assessed after 24-96 h exposure. Exposure of lumpfish larvae to the experimental concentrations resulted in a significant decrease in respiration rate (Lowest Observed Effect Concentration (LOEC) = 5-10 nM) and in the percentage of dark larvae (LOEC = 4 nM). However, no effects on respiration rate of cod larvae were detected. In addition to lumpfish larvae being affected at low concentrations of medetomidine, a reversibility of the effects was observed when 96 h-exposed larvae were incubated in clean seawater for 24-48 h. Considerations relating to the future commercialisation of medetomidine for antifouling purposes are discussed.
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| 8. |
- Bellas, Juan
(författare)
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Toxicity assessment of the antifouling compound zinc pyrithione using early developmental stages of the ascidian Ciona intestinalis
- 2005
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Ingår i: Biofouling. - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 21:5-6, s. 289-296
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the toxicity of zinc pyrithione (Zpt) on the early stages of development of the ascidian Ciona intestinalis . Larval morphological abnormalities were studied after the exposure of C. intestinalis embryos at different stages of development. The median effective concentrations (EC50 ) ranged from 226-590 nM. The larval settlement stage was the most sensitive to Zpt. Toxic effects of Zpt on larval settlement were detected at 9 nM (EC10). The inhibition of C. intestinalis embryonic development was also used to study the loss of toxicity in Zpt solutions exposed to direct sunlight and laboratory UV light. The results showed that the toxicity of Zpt solutions decreased but did not disappear after 4 h exposure to direct sunlight (EC50 = 484 nM) or UV light (EC50 = 453 nM), compared to control Zpt solutions prepared in dark conditions. On the basis of the present data, predicted no effect concentrations of Zpt to C. intestinalis larvae are lower than predicted environmental concentrations of Zpt in certain polluted areas and therefore, may pose a risk to C. intestinalis populations.
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| 9. |
- 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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| 10. |
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