Biofouling最新文献

'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.

Considering the presence of a complex biofilm and persistent inflammation in infected dental root canals, this study evaluated the cytotoxicity and inhibitory effect of phenolic acids on pro-inflammatory gene expression and multispecies biofilms for endodontic applications. First, cinnamic acid (CI) and caffeic acid (CA) were screened based on their inhibitory activity on oral bacteria and toxicity on fibroblasts and macrophages by colorimetric assays. Then, their effects on mRNA levels of pro-inflammatory markers were determined by qPCR in macrophages exposed to LPS. In addition, these compounds were also tested against dual-species and multispecies biofilms in root canals by scanning and confocal microscopy. CI and CA exhibited bactericidal effects against tested bacteria. Both compounds significantly reduced pro-inflammatory markers in a dose-dependent manner. CI and CA eliminated dual-species biofilms and significantly decreased multispecies biofilms. In summary, cinnamic acid and caffeic acid exhibited multifaceted biological activities and may be indicated as medicaments for endodontically compromised teeth.

This study evaluated the potential of slightly acidic electrolyzed water (SAEW) as an efficient and safe biofilm disinfectant for medical devices and implants. The results showed that SAEW rapidly eradicated planktonic bacteria and biofilms, outperforming NaClO. SAEW degraded proteins and eDNA in extracellular polymeric substances, thereby penetrating biofilms and acting on bacteria. SAEW-treated bacteria could not maintain normal morphology, resulting in bacterial lysis and death. SAEW downregulated biofilm-related genes, including cna, pvl and clfA of Staphylococcus aureus, and aap, icaR and sara of Staphylococcus epidermidis. Additionally, SAEW cleared biofilms on surgical devices and implants within 10 min or less. Furthermore, no significant difference in corrosion efficiency was observed between the SAEW group and the negative control group when tested on stainless steel, zinc alloy and brass. In conclusion, SAEW exhibited robust antibacterial and biofilm-eliminating capabilities, showing great potential as a disinfectant for medical devices and implants.

Biofouling organisms threaten biodiversity as their pelagic larvae settle on submerged surfaces and are transported on the hulls of ships. Conventional antifouling paints are effective but release toxic biocides. We evaluated a nature-based alternative using exudates from the native sea anemone Anthothoe chilensis. Crude and diluted exudates (100%, 70%, 50%) were tested on larval settlement and behaviour of the bryozoan Bugulina flabellata, and compared with seawater and exudates from the non-native Anemonia alicemartinae. Settlement was strongly reduced under 100% A. chilensis exudate, while diluted treatments did not differ from controls. Larvae also swam longer and explored less, indicating behavioural deterrence. By contrast, A. alicemartinae exudate did not affect behaviour. Adult interactions showed asymmetric chemical interference. These results suggest that A. chilensis exudates act as selective chemical deterrents influencing recruitment and competition, pending comprehensive chemical characterisation and toxicity assessment, to determine their suitability as potential antifouling agents.

Biofilm development, which occurs on numerous surfaces, can reduce the efficiency and increase operating costs in bioprocesses and fermentation. The current study proposes a strategy for biofilm inhibition by investigating the interactions between microorganisms and surfaces using an extended Derjaguin-Landau-Verwey-Overbeek (xDLVO) approach and cell partition index (CPI) technique. Glass slide and Petri dish surfaces were modified with different surfactants. The results show that modification increased CPI values and altered the interaction behavior from attractive to repulsive, between microbial cells and different surfaces. Secondary energy values calculated by xDLVO theory between microbial cells and modified surfaces were repulsive. Meanwhile, the secondary energy values calculated for microbial cells and unmodified glass slide (-31 kT) and Petri dish surfaces (-27 kT) were attractive between cells and surfaces. The current study has opened a window for research in the field of biofilm inhibition through a surface energetics approach.

This study reports the synthesis of a new polypyridine ruthenium(II) complex, [Ru(anth)₃]²⁺, which generates singlet oxygen (Φ_Δ = 0.98) and binds DNA (K_b = 9.8 × 10⁴ M^-1), leading to bacterial damage. The compound exhibited minimum inhibitory concentrations (MICs) of 31.25 µg mL^-1 against S. aureus ATCC 700698 and S. epidermidis ATCC 35984, and 125 µg mL^-1 against S. aureus ATCC 25923 and S. epidermidis ATCC 12228. The compound showed synergistic effects with ampicillin and additive effects with tetracycline. The complex significantly reduced biofilm biomass, viable cell counts, and metabolic activity. Scanning electron and confocal laser microscopy confirmed surface disruption and reduced viability. Gel electrophoresis indicated light-induced DNA photocleavage. Cytotoxicity in L929 fibroblasts was observed only above 125 µg mL^-1. These findings suggest that [Ru(anth)₃]²⁺ is a promising antimicrobial agent with multi-target activity, supporting its potential for antimicrobial drug development.

Limnoperna fortunei (Dunker, 1857 in GBIF Secretariat (2023)), an invasive species known for its high filtration rate, dense populations, and rapid dispersion, poses a significant threat to freshwater ecosystems in various regions worldwide. In hydraulic infrastructure, L. fortunei biofouling reduces operational efficiency, accelerates infrastructure degradation, shortens equipment lifespan, and poses safety risks and water contamination threats, incurring significant economic costs. Consequently, effective control measures for L. fortunei are urgently needed. Although substantial progress has been made in understanding and managing L. fortunei, with various strategies proposed-such as physical removal, chemical eradication, and biological control - few have been shown to provide long-term, widely applicable solutions in hydraulic engineering. This paper reviews the mechanisms of fouling by L. fortunei and the current prevention strategies, offering a scientific basis and guidance for developing more effective prevention and control technologies.

Efficacy of Actibromide^® (formulation of bromide with sodium hypochlorite) as a supplementary biocide for process seawater heat exchangers was evaluated on Perna viridis at Madras Atomic Power Station. Continuous chlorination (0.2 mg/L) required prolonged exposure for 100% mortality. Actibromide^® at 0.2, 0.5 and 1.0 mg/L achieved complete mussel mortality within 12, 7 and 4 days, respectively. Reactive oxygen species generation increased antioxidant enzyme activity like superoxide dismutase, catalase which was found to be higher in the digestive gland. Inhibition of cellular functions was evident in haemolymph, inducing DNA damage (34%) and acetylcholinesterase inhibition (80-91%). The study clearly demonstrated that Actibromide^® penetrates at the cellular level, causing severe damage to the gills and digestive glands, reducing feed consumption and inducing both neurotoxic and genotoxic effects resulting in mortality. Supplemental targeted dosing at 0.2 mg/L seems to be a promising strategy for effective green mussel control in cooling water systems.

Orodispersible films (ODFs) are an innovative oral drug delivery method benefiting pediatric, geriatric, and non-compliant patients. They are portable, easy to swallow, and enhance bioavailability. Hyaluronic acid (HA) stands out among hydrophilic polymers for oral delivery of antimicrobial agents. This study evaluated the physicochemical properties, in vitro release profile, and antimicrobial/antibiofilm activity of HA-based ODFs combined with the flavonoid morin, known for its antimicrobial properties. Antimicrobial activity and microbial viability were assessed via biomass quantification. The films were thin (12-27 µm), flexible, homogeneous, and mechanically resistant. A burst release of morin was observed, reaching complete release at 210 min. Cytotoxicity analysis confirmed the non-toxic profile, showing cell viability. HA-morin films significantly reduced Streptococcus mutans biofilm mass, viability, and acidogenicity compared to the controls. Findings confirmed the non-toxic, and their significant antibiofilm activity against S. mutans. This innovative mucoadhesive system has potential for managing dental diseases and oral drug delivery.

Plumbagin, also known as 5-hydroxy-2-methyl-1,4-naphthoquinone (PLB), is a naturally occurring naphthoquinone molecule that has demonstrated strong antibacterial and antibiofilm properties against Staphylococcus aureus (S. aureus). However, the potential of PLB to eradicate mature biofilms and the underlying mechanisms involved remain unclear. In this study explored the effects of PLB on disrupting mature S. aureus biofilms, focusing on its impact on the extracellular polymeric substances (EPS) and potential mechanisms of action. Crystal violet (CV) and XTT assays demonstrated that PLB significantly reduced both the biomass and metabolic activity of mature S. aureus biofilms in a concentration-dependent manner. High-content screening (HCS) imaging demonstrated that PLB treatment induced significant alterations in the biofilm EPS architecture, leading to a substantial reduction in overall biomass and average thickness, with disruption severity correlating positively with PLB concentration. Using molecular fluorescence probing techniques, this study found that treatment with PLB resulted in a marked reduction in EPS components, including extracellular polysaccharides (PIA), proteins, and extracellular DNA (eDNA), compared to untreated controls. Molecular docking analysis revealed that PLB strongly interacts with several key S. aureus proteins involved in EPS production, such as IcaA, IcaD, IcaB, IcaC, Bap, ClfB, and CidA, particularly binding strongly to the active sites of IcaA and Bap. Furthermore, gene expression analysis indicated that PLB downregulated genes associated with biofilm EPS production. Overall, these findings suggest that PLB effectively disrupts S. aureus biofilms by targeting the EPS. These results highlight PLB as a promising candidate for targeting mature S. aureus biofilms in chronic infections.