Biofouling最新文献

This work investigated the effect of Desulfovibrio caledoniensis (D. caledoniensis) and Pseudomonas aeruginosa (P. aeruginosa) on the microbiologically influenced corrosion (MIC) behaviour of 70Cu-30Ni alloy using surface analysis and electrochemical techniques. The results demonstrated that the mixed medium containing D. caledoniensis and P. aeruginosa further accelerated the MIC of 70Cu-30Ni alloy compared to the single species medium. The addition of exogenous pyocyanin (PYO) to the D. caledoniensis medium increased the maximum pit depth on 70Cu-30Ni alloy from 5.40 μm to 6.59 μm, and the corrosion current density (i_corr) increased by one order of magnitude. From the perspective of bioenergetics and extracellular electron transfer (EET), the comprehensive MIC mechanism of 70Cu-30Ni alloy induced by D. caledoniensis and P. aeruginosa was proposed.

This study evaluated conventional and alternative irrigation solutions combined with ultrasonic irrigant activation (UIA) against Fusobacterium nucleatum (F. nucleatum) and its endotoxin (LPS) in main root canal and dentinal tubules, using a new intratubular infection model. Seventy dentin cylinders were infected with F. nucleatum for seven days under anaerobic conditions and treated with 2.5% sodium hypochlorite (NaOCl), limewater + 2.5% NaOCl, and 10% ethanolic propolis extract (EEP), administered by syringe irrigation (SI) or UIA. Microbiological samples were collected before and after irrigation to determine CFU ml^-1 and LPS levels. Confocal microscopy assessed bacterial membrane damage with Live/Dead staining. Irrigation solutions effectively reduced CFU ml^-1. UIA caused greater damage to the bacterial membranes and reduced LPS levels. The ultrasonic activation of 10% EEP and limewater + 2.5% NaOCl were comparable to 2.5% NaOCl (p > 0.05). UIA improved the effectiveness of solutions, suggesting potential for alternative substances. Randomized clinical trials using these protocols are recommended.

The purpose of this study was to investigate dynamics of biofilm biomass on microparticles of natural material quartz sand and the artificial material polypropylene (plastisphere) as well as change in biofilm-forming microorganisms' number under a short-term in situ field study. In this study microparticles of polypropylene and quartz sand ranging in size from 3 to 5 mm were used. The total microbial count and the number of sulfate-reducing bacteria in the biofilm (by traditional culture-based microbiological methods) and the biofilm biomass (by the method with the crystal violet) were investigated. According to the determined microbiological indicators, over time (90 days) on the polypropylene it was observed decreasing of both the number of studied groups of microorganisms and the formation of a microbial biofilm, compared to the quartz sand. Determination of microbiological indicators of the materials surface allows understanding the aspects of their preservation/removal from the environment and requires additional research.

Simvastatin had minimum inhibitory concentrations of 32 to 128 µg/mL against Klebsiella pneumoniae isolates and hindered the biofilm-formation ability of 58.54% of the isolates. It considerably diminished the bacterial cell counts in the biofilms as revealed by scanning electron microscope. Also, qRT-PCR revealed a downregulation of the biofilm genes (bcsA, wza, and luxS) by simvastatin in 48.78% of the isolates. Moreover, simvastatin has significantly improved the survival of mice and decreased the burden of bacteria in the infected lungs. Also, the histological architecture was substantially improved in the simvastatin-treated group, as the alveolar sacs and bronchioles appeared normal with minimal collagen fiber deposition. The immunohistochemical studies exposed that the TNF-α, NF-kβ, and COX-2 immunostaining considerably declined in the simvastatin-treated group. Furthermore, ELISA exposed that both IL-1β and IL-6 were considerably diminished in the lungs of the simvastatin-treated group.

Extracts of Cryptocarya species have been shown to reduce biofilms, demonstrating their antimicrobial effects. The extracts can be fractionated to optimize their potential. In this study, we evaluated the antimicrobial activity of Cryptocarya moschata fractions against planktonic cells and biofilms of Candida albicans and Streptococcus mutans. Four fractions were prepared: 100% hexane, acetate/hexane 1:1, 100% ethyl acetate, and water. The effect of the fractions on planktonic cells was assessed by counting the colony-forming units per milliliter (CFU/mL). Biofilm tests included CFU/mL, cell metabolic activity, and qualitative analysis using confocal laser scanning microscopy (CLSM). Results were analyzed by the Mann-Whitney U test (α = 0.05). The fractions contained lipophilic constituents, styrylpyrones, glycosylated flavonoids, and alkaloids. Acetate/hexane (1:1) and 100% ethyl acetate fractions reduced the CFU/mL of planktonic C. albicans. C. moschata fractions did not affect planktonic S. mutans. For biofilms, the fractions reduced the CFU/mL (from 2-5 logs) and cell metabolic activity (approximately 80% reduction in a single-species biofilm). CLSM showed the fractions reduced microorganism viability and damaged the extracellular matrix of biofilms. We conclude that the acetate/hexane 1:1 and 100% ethyl acetate C. moschata fractions exhibit antimicrobial effects against biofilms.

Pseudomonas aeruginosa, an opportunistic pathogen often causes biofilm-linked infections. A combinatorial approach involving tetracycline (antibiotic) and cuminaldehyde (phytochemical) was explored to combat this infectious pathogen. The results showed that both tetracycline and cuminaldehyde individually demonstrated antibacterial effects. However, when the compounds were applied together, there was a significant increase in their antimicrobial potential. The determined fractional inhibitory concentration index of 0.43 indicated a synergistic interaction between the two compounds. Furthermore, a series of experiments demonstrated that the combined application of cuminaldehyde and tetracycline could lead to a significant enhancement of their antibiofilm potential. This enhanced antibiofilm potential was attributed to the accumulation of reactive oxygen species and increased cell membrane permeability. Besides, this combinatorial application reduced the secretion of various virulence factors from P. aeruginosa. Therefore, this combined approach holds promise for effectively treating P. aeruginosa biofilms.

Marine fouling is a global problem that harms the ocean's ecosystem and the marine industrial sector. Traditional antifouling methods use harmful agents that damage the environment. As a result, recent research has focused on developing environmentally friendly, long-lasting, and sustainable antifouling solutions. Scientists have turned to nature for inspiration, particularly the water-repellent properties found in the microstructures of plants, insects and animals like the lotus leaf, butterfly, and shark. This review summarizes the current trends in developing superhydrophobic materials and fabrication techniques for bionic antifouling strategies. These strategies mimic the surface microstructures of various biological species, including the lotus leaf, coral tentacles, and the skins of sharks, whales, and dolphins. The review also discusses the technological applications of these biomimetic materials and the challenges associated with implementing them in the marine sector. Overall, the goal is to harness the superhydrophobicity of natural surfaces to create effective antifouling solutions.

Nanotechnology is used in several biomedical applications, including antimicrobial and antibiofilm applications using nanomaterials. Bacterial biofilm varies according to the strain; the matrix is very strong and resistant. In this sense, phytosynthesis is an important method for combating bacterial biofilms through the use of metallic nanoparticles (silver, gold, or copper) with increased marketing and technical-scientific potential. In this review, we seek to gather the leading publications on the use of phytosynthesized metallic nanoparticles against bacterial biofilms. Furthermore, this study aims to understand the main characteristics and parameters of these nanomaterials, their antibiofilm efficiency, and the presence or absence of cytotoxicity in these developed technologies.

This research study delves into the hydrodynamic frictional characteristics of fouled panels coated with different types of coatings, investigating how fouling coverage and surface roughness influence drag. The investigation incorporates data on the overall percentage coverage of fouling, as well as roughness measurements obtained through a 3D profilometer. Drag data collected from a flowcell simulation of real-world flow conditions complements these measurements. Notably, the determination of the level of fouling leverages the capabilities of CIE L*a*b as an image analysis method, focusing on the overall coverage rather than individual fouling species. The objective is to illustrate how fouled panels perform under varying flow and coating conditions compared to their clean counterparts. Furthermore, the paper proposes a roughness scaling approach that considers both the percentage coverage and measured areal roughness for each coating type, encompassing both fouled and unfouled areas. This approach provides valuable insights into the combined effects of fouling and surface roughness on hydrodynamic performance, enhancing our understanding of the intricate interplay between these factors.

In this study, a comparison of biofilm formation, extracellular polymeric substances (EPS) production, protein and polysaccharides estimation, and protein profiling through SDS-PAGE, FTIR, GC-MS, ESI-MS, SEM, and AFM analysis were done for EPS from epilithic bacteria Brevundimonas faecalis BC1 obtained from monumental rock under normal room temperature and heat stressed condition. Heat stress (60 ± 2 °C) that simulates hot monumental rock surfaces during the summer season caused  bacteria BC1 to produce more EPS (8.56 g/L), biofilm, protein and polysaccharides, extra SDS-PAGE protein bands of different molecular weight than their control counterpart. FTIR and GC-MS analysis showed extra polysaccharide formation in the EPS under heat stress and ESI-MS analysis clearly showed differences in structural components of EPS from two different sources. Consistently, SEM and AFM showed more branching structural components with dentate spikes in the EPS obtained from a heat-stressed source than from its counterpart, suggesting their protective role toward heat stress and adhesive potential for biofilm.