Biofouling最新文献

The primary method for mitigating the growth of biofouling organisms on submerged surfaces is through the use of broad-spectrum biocides, such as irgarol, which can impact non-target species. We assessed the developmental and bioenergetic impacts of early-life-stage irgarol exposure on zebrafish (Danio rerio), including impacts on survival, hatching, developmental abnormalities, heart rate, mitochondrial function, and behaviour. We exposed zebrafish embryos 6-144 h post-fertilisation (hpf) to irgarol at concentrations currently detected in the environment and at pharmacological concentrations. At environmental concentrations, irgarol did not impact survival, hatching, morphological development or mitochondrial function. However, significant changes to heart rate and swimming behaviour occurred. Larvae were significantly hyperactive following exposure, then hypoactive after being grown in clean conditions for weeks. Our study showed that while irgarol is not acutely toxic at environmental levels, it has sublethal impacts on cardiac and neurological functions that could result in decreased fish fitness. The risks that irgarol presents to food security, environmental health, and human health warrant study.

Traditional antifouling coating evaluations rely on manual sample retrieval, imaging and subjective visual assessments, which are labour-intensive and constrained by infrequent sampling intervals that may overlook critical fouling developments. This study presents a novel, automated biofouling assessment system at the CoaST Maritime Test Centre. A custom underwater camera captures daily images, while advanced image analysis techniques track fouling progression. To address imaging challenges, a median stacking technique removes transient artefacts such as overhanging algae and floating debris, enabling accurate assessment of attachment points, the primary metric for biofouling coverage. Multi-exposure fusion enhances image illumination. For image analysis, ilastik, a machine-learning tool using a random forest algorithm, performs pixel classification segmentation to differentiate biofouling classes and monitor their growth. This automated approach improves accuracy, repeatability and efficiency in biofouling assessment, reducing subjectivity and enhancing antifouling research.

Twenty-three phenolic acids (1-23), including three novel sulfur-containing derivatives, along with five alkaloids (24-28) were isolated from the marine-derived fungus Aspergillus iizukae GXIMD 00548. Their structures were elucidated through comprehensive spectroscopic analysis and comparison with literature. All isolated compounds were evaluated for antifouling activities against barnacle larval settlement. Compounds 1-6, 8-11, 13, 20, 22 and 24-26 exhibited potent antifouling effects with median effect concentration (EC₅₀) values ranging from 0.03 to 11.03 μg/mL. Additionally, compounds 9, 10 and 13 showed acetylcholinesterase (AChE) inhibitory effects with half maximal inhibitory concentration (IC₅₀) values of 49.67 ± 0.08, 77.69 ± 0.09, and 127.5 ± 0.09 μM, respectively.

Ocimum gratissimum L. (African basil) is widely used in ethnomedicine to treat infectious and inflammatory conditions, yet its antifungal mechanisms remain unclear. In this study, we evaluated the essential oil of O. gratissimum L. (OGEO) against Candida albicans biofilms, a clinically relevant driver of antifungal resistance in device-associated infections. Gas chromatography-mass spectrometry identified eugenol as the predominant constituent (59.5%), supported by terpenoid and sesquiterpene derivatives. Functional assays demonstrated potent antibiofilm activity, as exposure to 1% and 2% OGEO reduced viable biofilm cells by >2 log₁₀ CFU/biofilm at Day 1 and sustained ∼70% inhibition at Day 3, with corresponding biomass reductions of ∼65% and ∼80%, respectively. Confocal microscopy revealed marked thinning and fragmentation of hyphal networks, while scanning electron microscopy confirmed collapse of extracellular matrix architecture. Kinetic modeling showed that OGEO induced an intermediate suppression profile, delaying biofilm recovery compared to untreated controls and fluconazole (which permitted ∼90% regrowth by Day 7), but without the sustained fungicidal effect observed with caspofungin (>80% suppression). Transcriptomic profiling at Day 3 identified 463 differentially expressed genes, with strong repression of hyphal regulators (HWP1, ALS3, EFG1, BCR1) and extracellular matrix-associated genes (FKS1, ZAP1), alongside upregulation of oxidative and proteotoxic stress pathways (SOD5, HSP90, MAPK signaling). Together, these data suggest that OGEO functions as a biofilm modulator rather than a fungicidal agent, weakening structural resilience and redirecting C. albicans into a stress-adaptive state. Clinically, this modulatory activity-marked by early biomass suppression, matrix destabilization, and transcriptional remodeling-highlights OGEO's potential as a prophylactic or adjunctive strategy in device-associated candidiasis. Applications may include medical device coatings or topical formulations that prevent biofilm initiation and enhance susceptibility to existing antifungal drugs.

Methicillin-resistant Staphylococcus aureus (MRSA) poses a major global health threat and is recognized by the World Health Organization as a high-priority pathogen for new drug development. MRSA's ability to form biofilms further complicates treatment and enhances antibiotic resistance. Antimicrobial peptides (AMPs) present a promising alternative to conventional antibiotics, however, their discovery remains labor-intensive. This study utilized computational and experimental approaches to evaluate the physicochemical properties, anti-MRSA activity against 10 clinical isolates, bacterial selectivity, cytotoxicity, and antibiofilm effects of AMPs. Temporin-PF (TPF) peptide was identified as a leading candidate and modified to generate TPF-M1, achieving an improved anti-MRSA score of 600.0. TPF-M1 exhibited enhanced killing activity and selectivity against MRSA with low toxicity toward human cells. At 20 µM, TPF-M1 effectively reduced MRSA biofilm viability using the transferable solid-phase pin lid method and disrupted the biofilm structure. These findings underscore the potential of AI-guided AMP development for anti-MRSA therapy.

Antibiotics incorporated into spacers do not guarantee complete eradication of infection. This study aimed to compare, in vitro, the antimicrobial activity of antibiotic-loaded cement with and without additional alternative antimicrobial molecules for the eradication of polymicrobial biofilms. Methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa (PA), and Candida albicans (CA) were selected to form mono- and polymicrobial biofilms on polyurethane sponges. Bone cement was supplemented with vancomycin, imipenem, silver nitrate (SN), and xylitol in different combinations. In monomicrobial biofilms, the combination of vancomycin + SN + xylitol showed superior activity against MRSA compared with other formulations. In polymicrobial biofilms, the combinations imipenem + vancomycin + xylitol, imipenem + vancomycin + SN, and imipenem + vancomycin + SN + xylitol were most effective in eradicating PA. For MRSA, all combinations achieved complete eradication, whereas CA eradication remained incomplete. Overall, the inclusion of SN and xylitol in cement improved antimicrobial performance compared with antibiotic-only formulations.

Resin materials enriched with bioglass (45S5) could potentially improve the physicochemical properties of dental materials. Specimens were categorized into five groups: (GIC)- conventional glass ionomer cement; (RMGIC.1)- resin-modified GIC with non-lyophilised polyacrylic acid, (RMGIC.1_45S5)- RMGIC.1 with 45S5 (10 w/w%); (RMGIC.2)- resin-modified GIC with freeze-dried polyacrylic acid; and (RMGIC.2_45S5)- RMGIC.2 with 45S5 (10 w/w%). The specimens were tested at acid/neutral pH, and the antibacterial activity colony-forming units (CFU/mg), sorption, solubility, calcium ion release, and bioactivity were measured in a Streptococcus mutans biofilm model. Analysis of variance and Scheffe/Tukey statistical tests were used. The 45S5 in the RMGICs resulted in higher alkalinization and the formation of calcium/phosphorus precipitates. RMGIC.1_45S5 improved pH stability and increased the sorption and solubility. In the S.mutans biofilm, none of the materials significantly increased the pH. The enrichment of RMGIC.1 (45S5) increased the sorption, solubility, calcium release, and showed bioactivity, but had no antimicrobial effect on the S.mutans biofilm model.

'Yellow water' issues frequently occur in drinking water supply systems on university campuses, primarily caused by the resuspension of loose sediments within pipelines, which may pose high potential microbiological risks. In order to investigate the accumulation of sediments accompanying microbiological risks in municipal pipelines, 'water + sediment' samples were collected periodically over two semesters in a university campus exhibiting divergent temperature patterns. Results indicated that sediment quantity increased rapidly within a short period; however, microbial biomass did not increase significantly. During the second semester with rising temperatures, the abundance of potential pathogens like Legionella spp. and Mycobacterium spp. increased markedly. Microbial community structure underwent an obvious succession over time in both semesters. This study found that short-term sediment accumulation in university campus drinking water supply systems did not pose immediate microbiological risks under the studied conditions. Pipeline pre-flushing before the start of each semester was recommended to mitigate microbiological risks.