• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.1
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• pp.30-34
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• 2012

The filamentous bacterium Leucothrix mucor, an epiphyte of seaweed, showed antifouling activity against Ulva pertusa spore settlement and germling development. The chemical constituents representing the antifouling activity were identified as giffinisterone B and oleamide based on nuclear magnetic resonance (NMR) spectroscopy and mass spectroscopy (MS). Approximately 3.6 mg of giffinisterone B and 2.8 mg of oleamide were isolated from 1.6 g of Leucothrix mucor crude extract. Giffinisterone B fully inhibited spore settlement and germling development at $100{\mu}g/mL$. Oleamide inhibited spore settlement at $10{\mu}g/mL$ and germling development at $100{\mu}g/mL$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.1
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• pp.53-58
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• 2013

The active antifouling compounds coumarin and its derivatives were isolated from the cinnamon tree Cinnamomum loureiroi. The antifouling activities were determined using representative soft fouling organisms: the seaweed Ulvapertusa and diatom Navicula annexa. The chemical constituents with antifouling activities were identified as coumarin, hydroxylcoumarin, coumaric acid, and cinnamaldehyde by interpreting nuclear magnetic resonance, and high-resolution mass spectroscopy data. These compounds were isolated from 1.09 g of crude Cinnamomum sp. methanol extract, yielding approximately 18.4, 6.3, 9.8, and 14.7 mg of coumarin, hydroxylcoumarin, coumaric acid, and cinnamaldehyde, respectively. The compounds inhibited U. pertusa zoospores with $EC_{50}$ values of $0.13-0.25{\mu}g/mL$, and the diatom N. annexa with $EC_{50}$ of $0.21-0.81{\mu}g/mL$.

• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.460-470
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• 2017

Mussels are major fouling organisms causing serious technical and economic problems. In this study, antifouling activity towards mussel was found in three compounds isolated from a marine bacterium associated with the sea anemone Haliplanella sp. This bacterial strain, called PE2, was identified as Vibrio alginolyticus using morphology, biochemical tests, and phylogenetic analysis based on sequences of 16S rRNA and four housekeeping genes (rpoD, gyrB, rctB, and toxR). Three small-molecule compounds (indole, 3-formylindole, and cyclo (Pro-Leu)) were purified from the ethyl acetate extract of V. alginolyticus PE2 using column chromatography techniques. They all significantly inhibited byssal thread production of the green mussel Perna viridis, with $EC_{50}$ values of $24.45{\mu}g/ml$ for indole, $50.07{\mu}g/ml$ for 3-formylindole, and $49.24{\mu}g/ml$ for cyclo (Pro-Leu). Previous research on the antifouling activity of metabolites from marine bacteria towards mussels is scarce. Indole, 3-formylindole and cyclo (Pro-Leu) also exhibited antifouling activity against settlement of the barnacle Balanus albicostatus ($EC_{50}$ values of 8.84, 0.43, and $11.35{\mu}g/ml$, respectively) and the marine bacterium Pseudomonas sp. ($EC_{50}$ values of 42.68, 69.68, and $39.05{\mu}g/ml$, respectively). These results suggested that the three compounds are potentially useful for environmentally friendly mussel control and/or the development of new antifouling additives that are effective against several biofoulers.

• Korean Journal of Environment and Ecology
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• v.29 no.5
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• pp.736-742
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• 2015

Cosmopolitan green macroalga, Ulva pertusa is a widely spread species in most coastal waters. This benthic alga is appearing on marine objectives causes significantly economical and social problems. To prevent fouling organisms, new antifouling (AF) agents, such as ziram, diruon, zinc pyrithione, copper pyrithione, DBNPA and triclosan are used. However, the evaluations of new antifouling system of those agents strongly need more information on algae species for considering environment effect. Therefore, the purpose of this study was to evaluate the activity of antifouling system using Ulva spores and Nitzschia pungens. In addition, new AFS were evaluated the toxicity of microalga, Nitzschia pungens. In the motility of Ulva spores, ziram and zinc pyrithione were shown 50% higher inhibition motility than diuron, copper pyritione, DBNPA and triclosan. Ziram was appered the highest AFS of Ulva sore attachment. Copper pyrithione at the concentration of $100{\mu}g/L$ was inhibited 80% growth rate comparison of control. In conclusion, each new AF agents showed their specific AF activities against marine organisms based on this work.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.2
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• pp.253-258
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• 2016

The $MnO_x-WO_3-TiO_2$ nanoscale powders were synthesized by sol-gel method in order to prevent the biological fouling on the ships and offshore structures. Powder characteristics and antifouling performance were investigated with respect to the crystalline, microstructure and surface property for application in self-polishing copolymer resins. The high antifouling activity of $TiO_2$-system biocide was attributed to its redox potential and soluble metal ions originating from tungsten oxides according to the improvements in the powder characteristics. Based on their physio-chemical characterizations, the specific surface areas of powders were about $90m^2/g$ and the grain size was in the region 100 ~ 150 nm. Powder characteristics and surface properties were improved by the addition of $WO_3$. Antifouling performance were analyzed according to their surface properties and static immersion tests to determine the effects of the $TiO_2$-system compounds. The surface of 2 wt. % added sample was clean for 5 month. This may be attributed to the ability of $MnO_x-WO_3-TiO_2$ powders to act as a promoter in antifouling agents.

• Fisheries and Aquatic Sciences
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• v.8 no.2
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• pp.51-55
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• 2005

We measured the anti-attachment activity of allelochemical and antifouling substances using monospores from Porphyra yezoensis Ueda as an assay. Methanol or aqueous extracts ($20/{\mu}g/mL$) from 32 seaweeds were added to monospore suspensions. Methanol extracts of Corallina pilulifera, Ishige sinicola, Sargassum horneri, and Sargassum sagamianum inhibited attachment $by\;>90\%$ compared to the reference. Phenolic compounds fractionated from S. sagamianum caused the most potent inhibition. P. yezoensis monospores also showed significant sensitivity to known allelochemical and algicidal compounds.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.356-366
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• 2021

Two marine actinobacterial isolates, RG3 and RG8, were identified using 16Sr DNA as Streptomyces althioticus RG3 and Streptomyces californicus RG8 and submitted to the database of genetic information with accession numbers MW661230 and MW661234, respectively; they were found to have emulsification indexes of 60 ± 2.5% and 53 ± 2.2%, respectively. The biosurfactants obtained were stable at a temperature of 35℃ for both strains; they were stable at 10% NaCl, in the case of S. althioticus RG3 and at 10-15% NaCl in the case of Str.californicus RG8; both strains produced the most biosurfactant when exposed to alkaline conditions. We characterized the biosurfactants, including features such as their chemical composition, using Fourier transform infrared spectroscopy analysis. The antimicrobial activity of the biosurfactant extracts was evaluated using the well diffusion method against Vibrio alginolyticus MK170250, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 4027, and Staphylococcus aureus ATCC 25923. S. althioticus RG3 biosurfactants were found to have better antimicrobial activity than those of Str. californicus RG8, indicating that they may be used in pharmaceutical industries and in the manufacture of antifouling products.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.379-379
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• 2006

AcAP was prepared by reacting p-hydroxyacetophenone (HAP) with acryloyl chloride (Ac) in presence of triethylamine (TEA) in MEK at $0^{\circ}C$. The reaction was monitored by TLC and the prepared monomer was characterized by UV, IR, $^{1}H-NMR\;and\;GC-MS$. The homo- [poly (AcAP)] and copolymers [poly (AcAP-co-MMA)] were prepared by solution polymerization at $70^{\circ}C$, in which BPO as initiator. The molecular weight of the polymers was determined by GPC. In order to find out the AF activity of prepared polymers, representatives of marine microfoulers, shipfouling bacteria (B. macroides & P. aeruginosa) and microalgae (A. coffeaeformis & N. incerta) were screened. The results of antibacterial activity and diatom attachment assays revealed potential AF efficiency of these polymers.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.381-381
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• 2006

AcDP and AcAP were prepared by the reaction of acryloyl chloride (Ac) with 2,4,4' -trichloro-2' -hydroxydiphenyl ether (DP) and p-hydroxyacetophenone respectively in presence of triethylamine (TEA) in MEK at $0^{\circ}C$. The reaction was monitored by TLC and the prepared monomer was characterized by UV, IR, $1^H-NMR$ and GC-MS. Further, copolymers poly (AcDP-MMA-AcAP) were prepared in different feed ratio of monomers by free radical polymerization at $70^{\circ}C$, in which BPO as initiator and their molecular weight was determined by GPC. The AF activity of prepared polymers was investigated against representatives of marine microfoulers, shipfouling bacteria (B. macroides & P. aeruginosa) and microalgae (A.coffeaeformis & N. incerta). The antibacterial activity and diatom attachment assays showed significant AF potential of these polymers.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.05a
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• pp.68-69
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• 2003

Tributyltin (TBT) used world-wide in antifouling paints for ships is a widespread environmental pollutant and cause reproductive organs atrophy in rodents. At low doses, antiproliferative modes of action have been shown to be involved, whereas at higher doses apoptosis seems to be the mechanism of toxicity in reproductive organs by TBT. (omitted)