Search Results (24)

Background/Objectives: Tributyltin (TBT), a potent biocide used in antifouling paints, is highly toxic to aquatic environments, causing oxidative stress, endocrine dysfunction, and metabolic disorders in aquatic organisms, including crustaceans. The blue crab Callinectes sapidus is an economically and ecologically important species in several countries worldwide and is considered an invasive species in Europe. Methods: This study evaluated the effects of 7 days of exposure to environmentally relevant TBT concentrations (100 and 1000 ng.L⁻¹) on the intermediary metabolism and oxidative balance of the blue crab Callinectes sapidus. After exposure, hemolymph samples were analyzed to determine glucose, lactate, total protein, and cholesterol levels. In tissue samples, concentrations of triglycerides, glycogen, total glutathione (GSH), reactive oxygen species (ROS), sulfhydryls, lipid peroxidation (LPO), and glutathione S-transferase (GST) activity were assessed. Results: In the hemolymph, glucose and lactate levels increased, while the total cholesterol, triglycerides, and total proteins decreased in all exposed groups. The GST activity increased in exposed tissues, while the total GSH and sulfhydryl content decreased. The ROS concentration increased in response to higher TBT concentrations. Conclusions: These findings highlight the toxicity of TBT and show that 7 days of exposure to environmentally relevant concentrations disrupts the metabolic homeostasis and oxidative balance in C. sapidus. Additionally, this study demonstrates that C. sapidus is sensitive to TBT exposure and has potential as a model species for ecotoxicological studies. Full article

Microbial deterioration poses a significant threat to built heritage, particularly mural paintings, where traditional synthetic biocides can have adverse environmental and material impacts. This study evaluates the effectiveness of essential oils derived from four aromatic plants—thyme (Thymus mastichina L.), fennel (Foeniculum vulgare Mill.), pennyroyal (Mentha pulegium L.), and green lavender (Lavandula viridis L’Hér.)—as natural biocides against microorganisms isolated from mural paintings in the House of Moscadim, an 18th-century manor house in Portugal. The antimicrobial activity of the essential oils was assessed using both direct contact and micro-atmosphere methods. Four microorganisms were isolated, including two bacteria, Bacillus wiedmannii and Bacillus mobilis, and two fungi, Penicillium brevicompactum and Cladosporium cladosporioides. Fennel essential oil exhibited the strongest antifungal activity against both fungal species, surpassing the efficacy of the commercial biocide Biotin T^® in some cases. Pennyroyal and lavender essential oils also showed significant inhibitory effects. The micro-atmosphere method demonstrated the potential for noninvasive application of essential oils while preserving the integrity of delicate mural surfaces. These findings suggest that essential oils, particularly fennel oil, constitute a promising natural alternative to synthetic biocides for the sustainable conservation of cultural heritage. Further research is recommended to explore their long-term effects and to optimize application techniques. Full article

The current scenario of antifouling (AF) strategies to prevent the natural process of marine biofouling is based in the use of antifouling paints containing different active ingredients, believed to be harmful to the marine environment. Compounds called booster biocides are being used with copper as an alternative to the traditionally used tributyltin (TBT); however, some of them were recently found to accumulate in coastal waters at levels that are deleterious for marine organisms. More ecological alternatives were pursued, some of them based on the marine organism mechanisms’ production of specialized metabolites with AF activity. However, despite the investment in research on AF natural products and their synthetic analogues, many studies showed that natural AF alternatives do not perform as well as the traditional metal-based ones. In the search for AF agents with better performance and to understand which molecular motifs were responsible for the AF activity of natural compounds, synthetic analogues were produced and investigated for structure–AF activity relationship studies. This review is a comprehensive compilation of AF compounds synthesized in the last two decades with highlights on the data concerning their structure–activity relationship, providing a chemical toolbox for researchers to develop efficient nature-inspired AF agents. Full article

The rapid increase in the antibiotic resistance of microorganisms, capable of causing diseases in humans as destroying cultural heritage sites, is a great challenge for modern science. In this regard, it is necessary to develop fundamentally novel and highly active compounds. In this study, a series of N⁴-alkylcytidines, including 5- and 6-methylcytidine derivatives, with extended alkyl substituents, were obtained in order to develop a new generation of antibacterial and antifungal biocides based on nucleoside derivatives. It has been shown that N⁴-alkyl 5- or 6-methylcytidines effectively inhibit the growth of molds, isolated from the paintings in the halls of the Ancient Russian Paintings of the State Tretyakov Gallery, Russia, Moscow. The novel compounds showed activity similar to antiseptics commonly used to protect works of art, such as benzalkonium chloride, to which a number of microorganisms have acquired resistance. It was also shown that the activity of N⁴-alkylcytidines is comparable to that of some antibiotics used in medicine to fight Gram-positive bacteria, including resistant strains of Staphylococcus aureus and Mycobacterium smegmatis. N⁴-dodecyl-5- and 6-methylcytidines turned out to be the best. This compound seems promising for expanding the palette of antiseptics used in painting, since quite often the destruction of painting materials is caused by joint fungi and bacteria infection. Full article

Today, one of the biggest challenges is infections in the painted walls of hospitals. Acrylic-based paints are a target of antibiotic-resistant microorganisms since they contain cellulosic compounds as thickeners. The aim of this study was to synthesize and investigate the biocidal activity and toxicity of heterophase ZnO-Ag nanoparticles fixed in water-based acrylic paint layers in reference to a nontreated water-based paint. The ZnO-Ag nanoparticles with average particle sizes of about 80 nm were simply obtained by electrical explosion of two twisted wires in an oxygen-containing atmosphere. The nanoparticles and modified paint were characterized using SEM, TEM, XPS, and XRD techniques. The antimicrobial activity of the nanoparticles and modified paint layers was tested against P. aeruginosa, S. aureus, MRSA, E. coli bacteria, and C. albicans using ISO 22196. The antiviral activity against smallpox virus was tested according to ISO 21702. Flow cytometry tests were used to investigate the toxicity of the modified paint coating. As-synthesized nanoparticles had “Janus-like” morphology, with a clear interface inside the nanoparticle. Nanoparticles had enhanced antibacterial activity, which is based on the nanoparticle photocatalytic activity in water decomposition and reactive oxygen species generation. The paint coating with a ZnO-Ag nanoparticle mass ratio of 1.0 wt.% displayed significant antibacterial activity (more than a 99% reduction) and 100% antifungal activity. In addition, this coating inactivates >99% of the virus after 2 h of contact relative to a nontreated control paint. The paint coating showed low toxicity against the sensitive 3T3 fibroblast cell line. More than 90% cell viability was observed after 24 h of incubation with the sample extract. Therefore, heterophase ZnO-Ag nanoparticles have high biocidal activity and low toxicity use and can be applied to other commercial water-based paints to improve their performance against pathogens. Full article

Diuron, an additive biocide in antifouling paints, is widely employed to curtail the attachment of organisms on submerged surfaces in aquatic structures. Despite the detection of diuron in aquatic ecosystems, information regarding its acute and chronic impacts on aquatic invertebrates, particularly planktonic crustaceans, remains limited. In this study, we analyzed the acute (24 h) and chronic (12 days exposure across three generations) effects of different concentrations of diuron (1/10 of the no observed effect concentration (NOEC), the NOEC, and 1/10 of the lethal concentration 50% (LC50), derived from the 24 h acute toxicity value of 1152 μg L⁻¹) on the harpacticoid copepod Tigriopus japonicus. The acute exposure experiment indicated that the 1/10 LC50 value of diuron significantly reduced the copepod’s feeding rate and acetylcholinesterase activity. In response to the 1/10 LC50 value, the intracellular reactive oxygen species were elevated alongside increased malondialdehyde levels, while the glutathione content was depleted. The enzymatic activities of glutathione S-transferase, catalase, and superoxide dismutase were significantly enhanced by the 1/10 LC50 value, suggesting a proactive role of the antioxidant defense system against oxidative stress. Conversely, the activities of glutathione peroxidase and glutathione reductase enzymes were increased at the NOEC value, while their values were reduced by the 1/10 LC50 value. Chronic exposure to 1/10 NOEC and NOEC values revealed the adverse multigenerational effects of diuron. The second generation exhibited the most sensitivity to diuron, with the NOEC value notably reducing survival rate, body length, nauplius-to-adult development, neonates per brood count, and extending the reproduction period. Taken together, our findings underscore that even sublethal diuron levels can adversely impact copepod populations across generations through intergenerational toxicity. Full article

Natural antifoulants have received significant interest in the search for non- or less-toxic antifouling coating systems for marine structures. Capsaicin, a natural compound that can be found in chili peppers, is known as an environmentally friendly antifouling agent with an excellent performance and a low environmental impact. However, controlling its release from the coating matrix is still an issue to be solved. With the aim of developing an eco-friendly antifouling system with prolonged long-term activity, in this study, we incorporated capsaicin in combination with dichlofluanid into water-based acrylic coating formulations. The antifouling activity of the resulting coatings was studied by examining the survival behavior of a Gram-negative marine bacterium Aeromonas Salmonoid ATCC 33658, and the release rate of capsaicin from the paint matrix was also assessed. The combination of 0.75 wt.% capsaicin and 0.75 wt.% dichlofluanid into the same matrix showed an antibacterial performance of up to 99.9% cfu reduction with an antibacterial value R 2.5–3 times higher than those obtained with the single biocides at 1.5 wt.%. The association between the two organic biocides created a synergistic effect on the antifouling performance, further resulting in a prolonged activity. Full article

With the increasing awareness of environmental protection, it is necessary to develop natural product extracts as antifouling (AF) agents for alternatives to toxic biocides or metal-based AF paints to control biofouling. This paper briefly summarizes the latest developments in the natural product extracts and their derivatives or analogues from marine microorganisms to terrestrial plants as AF agents in the last five years. Moreover, this paper discusses the structures–activity relationship of these AF compounds and expands their AF mechanisms. Inspired by the molecular structure of natural products, some derivatives or analogues of natural product extracts and some novel strategies for improving the AF activity of protective coatings have been proposed as guidance for the development of a new generation of environmentally friendly AF agents. Full article

Although subterranean tombs are largely protected from the external environment, the colonization of microorganisms threatens their conservation. Conventional biocides have negative effects on the environment, human health, and the sensitive materials in ancient tombs, especially painted murals. Therefore, we tested the biocidal effects of 11 plant-extracted essential oils (EOs) against two fungal strains and four bacterial strains isolated from Buyeo Royal Tomb No. 1, a World Heritage Site in South Korea. Oregano, clove bud, thyme, and cinnamon cassia EOs showed the highest antifungal and antibacterial activities. At concentrations suitable for practical application (3–10%), oregano and cinnamon cassia EOs exhibited the highest antifungal and antibacterial activities against the tested microbial strains. No variation in the surface properties and mineral composition was detected for the lithotype specimens (granite and gneiss) treated with the EOs at 1–10%. Low-concentration thyme and oregano EOs led to minimal color change in the painting layer specimens, whereas clove bud and cinnamon cassia EOs caused yellowing of the oyster shell white pigment at a concentration of 3–10%. Our results suggest that 3% oregano EO is a candidate biocide that could minimize the biological damage to and promote the conservation of ancient tomb murals. Full article

This study focused on the antifouling effect of copper oxide (Cu₂O)- and zineb-based coatings against Cyanothece sp. ATCC 51142 by analysing photosynthetic activity using chlorophyll fluorescence. The photoautotrophically grown cyanobacterium was exposed to toxic coatings over a short-term period of 32 h. The study showed that Cyanothece cultures are particularly sensitive to biocides (i) released from antifouling paints and (ii) exhibited by contact with the coated surfaces. Changes in the maximum quantum yield of photosystem II (F_V/F_M) were observed within the first 12 h of exposure to the coatings. Partial recovery of F_V/F_M in Cyanothece was revealed 24 h post exposure to a copper- and zineb-free coating. In this research, we proposed an analysis of the evaluation of fluorescence data to study the initial response of cyanobacterial cells to copper- and non-copper-based antifouling coatings formulated with zineb. We evaluated the dynamics of coating toxicity by determining the characteristic time constants of changes in the F_V/F_M. Within the most toxic paints studied, those formulated with the highest concentration of Cu₂O and zineb, the estimated time constants were 3.9 times lower compared to the copper- and zineb-free paint. The use of zineb in copper-based antifouling coatings enhanced the toxic effect of paints and contributed to a faster decline in photosystem II activity in Cyanothece cells. The analysis we proposed, along with the fluorescence screening results, may be useful in evaluating the initial antifouling dynamic action against photosynthetic aquacultures. Full article

Weather conditions affect biocides on exposed outer surfaces on constructions. Contact with water causes hydrolysis and leaching of substances. Ultraviolet radiation may induce photolysis. As a result, a mixture of biocidal active substances and transformation products can be emitted into the environment. In a semi-field study, leaching of the biocidal active substances terbutryn, diuron, octylisothiazolinone, carbendazim, and selected transformation products was observed for two paints containing either a white or a red pigment. Painted test panels were exposed to natural weathering for about 1.5 years. Runoff samples were analyzed during the course of the experiment. At the end of the study, residues of biocidal active substances and transformation products were determined in sections of the test panels. Emissions of substances were mainly observed during the first few months of the experiments. Increased emissions of transformation products were observed during periods of increased global radiation and subsequent periods with relatively high amounts of driving rain. Different patterns of transformation products were observed, especially for terbutryn, both for paints containing different pigments and in experiments that were started in different periods of the year, as well as during different periods of the experiments. Full article

Marine biofouling is defined as the undesirable colonization of submerged man-made surfaces by fouling organisms (microfoulers and macrofoulers) and represents a major economic nuisance for maritime industries worldwide on account of the drag friction increase on ships’ hulls resulting in the over-consumption of fuel and high maintenance costs. The most commonly used strategy to prevent marine biofouling is based on antifouling (AF) paints containing bioactive compounds. However, some of the AF compounds used have been found to be toxic towards target and non-target organisms, which raises many environmental issues. Thus, the development of new eco-friendly AF agents has been a priority. Portoamides (PAs), natural cyclic dodecapeptides isolated in our group from the cyanobacterium Phormidium sp. LEGE 05292 from the Blue Biotechnology and Ecotoxicology Culture Collection (LEGE-CC), have shown strong potential as a more sustainable active ingredient in AF compositions. These PAs showed high effectiveness in the prevention of mussel larvae settlement (EC50 = 3.16 μM), and also bioactivity towards growth and biofilm disruption of marine biofouling bacterial strains, while not showing toxicity towards both target and non-target species. Considering the great potential of these natural products in the field of antifouling solutions, in this work, the incorporation of the PAs in commercial polyurethane and silicone (PDMS)-based marine coatings, followed by a proof-of-concept test in real sea conditions (Leixões Port), was carried out to demonstrate their industrial applicability. The in situ test showed effectiveness in the ability to prevent the colonization of fouling organisms on substrates coated with PAs-based marine coating when compared with control, and even compared with the commercial biocide Econea. These results highlight the potential of natural products as active ingredients in new more environmentally friendly marine coatings to prevent biofouling. Full article

Fouling is the accumulation of unwanted substances, such as proteins, organisms, and inorganic molecules, on marine infrastructure such as pylons, boats, or pipes due to exposure to their environment. As fouling accumulates, it can have many adverse effects, including increasing drag, reducing the maximum speed of a ship and increasing fuel consumption, weakening supports on oil rigs and reducing the functionality of many sensors. In this review, the history and recent progress of techniques and strategies that are employed to inhibit fouling are highlighted, including traditional biocide antifouling systems, biomimicry, micro-texture and natural components systems, superhydrophobic, hydrophilic or amphiphilic systems, hybrid systems and active cleaning systems. This review highlights important considerations, such as accounting for the effects that antifouling strategies have on the sensing mechanism employed by the sensors. Additionally, due to the specialised requirements of many sensors, often a bespoke and tailored solution is preferential to general coatings or paints. A description of how both fouling and antifouling techniques affect maritime sensors, specifically acoustic sensors, is given. Full article

Surfaces with antimicrobial properties are gaining notoriety as an efficient method to avoid surface contamination. Self-disinfecting paints are a promising strategy towards cleaner indoor environments by preventing the colonization of walls with microorganisms. However, its widespread use needs an appropriate toxicological safety evaluation due to the potential for biological disturbance associated to its biocidal activity. In this work, the cyto- and genotoxic assessment of two self-disinfecting paints containing the antimicrobial substances triclosan (TCS) and isoborneol (ISB) is performed. HaCaT and A549 cell lines models were selected for the in vitro assessment. To evaluate the cytotoxicity, tests by direct contact and on extracts obtained from leaching were performed following ISO 10993, whereas the genotoxicity was assessed by comet assay and cytokinesis-block micronucleus (CBMN) assay. The results showed low levels of cyto- and genotoxicity under the models and conditions tested, indicating that these substances have commercial potential. Full article

To evaluate the effects of antifouling paints and biocides on larval settlement and metamorphosis, newly hatched swimming larvae of the compound ascidian Botryllus schlosseri, a dominant species of soft-fouling in coastal communities, were exposed to (i) substrata coated with seven antifouling paints on the market containing different biocidal mixtures and types of matrices and (ii) sea water containing various concentrations of eight biocidal constituents. All antifouling paints showed high performance, causing 100% mortality and metamorphic inhibition, with ≥75% not-settled dead larvae. All antifouling biocides prevented the settlement of larvae. The most severe larval malformations, i.e., (i) the formation of a bubble encasing the cephalenteron and (ii) the inhibition of tail resorption, were observed after exposure to metal and organometal compounds, including tributyltin (TBT) at 1 μM (325.5 µg L⁻¹), zinc pyrithione (ZnP) at 1 μM (317.7 µg L⁻¹), and CuCl at 0.1 μM (98.99 µg L⁻¹), and to antimicrobials and fungicides, including Sea-Nine 211 at 1 μM (282.2 µg L⁻¹) and Chlorothalonil at 1 μM (265.9 µg L⁻¹). The herbicides seemed to be less active. Irgarol 1051 was not lethal at any of the concentrations tested. Diuron at 250 μM (58.2 mg L⁻¹) and 2,3,5,6-tetrachloro-4-(methylsulphonyl)pyridine (TCMS pyridine) at 50 μM (14.8 mg L⁻¹) completely inhibited larval metamorphosis. These results may have important implications for the practical use of different antifouling components, highlighting the importance of their testing for negative impacts on native benthic species. Full article