Search Results (187)

Cyanobacteria, particularly Microcystis aeruginosa, can form dense blooms that impair water quality, and conventional treatment methods often fail to remove them effectively. This study evaluated the impact of cell age on the performance of the UV/H₂O₂ advanced oxidation process against M. aeruginosa. Cultures of M. aeruginosa were monitored over 64 days at an initial culture density of 1.20 × 10⁶ cells mL⁻¹. For the UV/H₂O₂ experiments, cells were adjusted to a density of 5.00 × 10⁵ cells mL⁻¹, and the growth and oxidative experiments were monitored using parameters such as hydrogen peroxide decay concentration, optical density at 730 nm (OD₇₃₀), cell density, and dissolved organic carbon (DOC). The hydrogen peroxide (H₂O₂) dosages used were 20 mg L⁻¹ and 50 mg L⁻¹, and the results showed that despite varying cell ages, H₂O₂ consumption remained stable at both dosages. While optical density and cell count indicate total cell removal, DOC levels increased due to cell lysis, resulting in contributions from both intracellular and extracellular fractions. A linear correlation was found between cell density and OD₇₃₀, and between total DOC and cell density. In conclusion, cell age did not influence the effectiveness of the UV/H₂O₂ process under the conditions tested. These findings indicate that UV/H₂O₂ can be an effective approach for managing cyanobacterial blooms in water treatment systems, with its performance being unaffected by cell age. Full article

Background: Non-absorbable polyvinyl alcohol sponges (Merocel) are widely used in otolaryngology for nasal and ear packing but are prone to bacterial colonization and biofilm formation, which may increase infection risk and drive frequent use of systemic antibiotics. Sustained-release drug delivery systems enable prolonged local antiseptic activity at the site of packing while minimizing systemic exposure. Methods: We developed a sustained-release varnish containing chlorhexidine (SRV-CHX) and coated sterile Merocel sponges. Antibacterial, in vitro, activity against Staphylococcus aureus and Pseudomonas aeruginosa was evaluated using kinetic diffusion assays on agar, optical density (OD₆₀₀) measurements of planktonic cultures, drop plate, ATP-based viability assays, biofilm analysis by MTT metabolic assay, crystal violet bio-mass staining, high-resolution scanning electron microscopy (HR-SEM), and spinning disk confocal microscopy. Results: SRV-CHX-coated sponges produced sustained zones of inhibition on agar plates for up to 37 days against S. aureus and 39 days against P. aeruginosa, far exceeding the usual 3–5 days of clinical sponge use. Planktonic growth was significantly reduced compared with SRV-placebo, and a bactericidal effect persisted for up to 16 days for S. aureus and 5 days for P. aeruginosa before becoming predominantly bacteriostatic. Biofilm formation was markedly inhibited, with suppression of metabolic activity and biomass for at least 33 days for S. aureus and up to 16 days for P. aeruginosa. HR-SEM and confocal imaging confirmed sparse, discontinuous biofilms and predominance of non-viable bacteria on SRV-CHX-coated sponges compared with dense, viable biofilms on the placebo controls. Conclusions: Coating Merocel sponges with SRV-CHX provides prolonged antibacterial and anti-biofilm activity against clinically relevant pathogens. This strategy may reduce dependence on systemic antibiotics and improve infection control in nasal and ear packing applications in otolaryngology. Full article

Objectives: This systematic review and meta-analysis aimed to evaluate microbial adhesion and biofilm formation on additively manufactured composite-based orthodontic clear aligners compared with thermoformed aligners and other conventional polymeric materials. The influence of material composition, surface roughness, post-processing parameters, and cleaning protocols on microbial colonization was also assessed. Methods: A comprehensive search of PubMed, EMBASE, Scopus, Web of Science, and the Cochrane Library was conducted up to September 2025. Only in vitro studies investigating microbial adhesion, biofilm biomass, or microbiome changes on three-dimensional (3D)-printed aligner composites were included. Primary outcomes consisted of colony-forming units (CFU), optical density (OD) from crystal violet assays, viable microbial counts, and surface roughness. Risk of bias was assessed using the RoBDEMAT tool. Data were narratively synthesized, and a random-effects meta-analysis was performed for comparable datasets. Results: Five studies fulfilled the inclusion criteria, of which two in vitro studies were eligible for meta-analysis. Microbial adhesion and biofilm accumulation were influenced by the manufacturing technique, composite resin formulation, and surface characteristics. Certain additively manufactured aligners exhibited smoother surfaces and reduced bacterial adhesion compared with thermoformed controls, whereas others with increased surface roughness showed higher biofilm accumulation. Incorporating bioactive additives such as chitosan nanoparticles reduced Streptococcus mutans biofilm formation without compromising material properties. The meta-analysis, based on two in vitro studies, demonstrated higher OD values for bacterial biofilm on 3D-printed aligners compared with thermoformed aligners, indicating increased biofilm biomass (p < 0.05), but not necessarily viable bacterial load. Conclusions: Microbial adhesion and biofilm formation on 3D-printed composite clear aligners are governed by resin composition, additive manufacturing parameters, post-curing processes, and surface finishing. Although certain 3D-printed materials display antibacterial potential, the limited number of studies restricts the generalizability of these findings. Clinical Significance: Optimizing composite formulations for 3D printing, alongside careful post-curing and surface finishing, may help reduce microbial colonization. Further research is required before translating these findings into definitive clinical recommendations for clear aligner therapy. Full article

Tuta absoluta (Meyrick) is a globally invasive lepidopteran pest that has developed resistance to multiple classes of chemical insecticides, posing major challenges for the sustainable production of Solanaceae crops. In this study, we investigated the physiological and molecular responses of T. absoluta larvae to infection by the entomopathogenic bacterium Serratia marcescens (Bizio) strain Tapa21, which was isolated from naturally infected larvae and characterized through phenotypic, molecular, and phylogenetic analyses. Laboratory bioassays demonstrated dose- and time-dependent mortality of T. absoluta larvae, with mortality reaching nearly 80% at the highest Tapa21 concentration at 120 h post-infection (hpi), with a median lethal concentration (LC₅₀) of Optical Density (OD)₆₀₀ = 0.52 and a median lethal time (LT₅₀) of 5.2 d. RNA-Seq was performed, revealing 493 differentially expressed genes (DEGs), including 304 up-regulated and 189 down-regulated transcripts. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses indicated activation of detoxification-related enzymes, lysosome- and immune-associated pathways, and metabolic reprogramming, suggesting coordinated defense responses. A subset of genes, randomly selected across expression levels, was validated by RT-qPCR, corroborating the transcriptomic results. These results delineate the molecular mechanisms by which T. absoluta reshapes its physiological state during bacterial challenge and provide insight into how entomopathogenic strain Tapa21 disrupts host homeostasis. Such a mechanistic understanding could potentially contribute to sustainable and integrated pest management (IPM) strategies. Full article

Quantifying microbial growth with high temporal resolution remains essential yet challenging due to limitations of optical, manual, and biochemical methods. Here, we introduce an AI-enhanced electrochemical impedance spectroscopy platform for real-time, label-free monitoring of Saccharomyces cerevisiae growth. Broadband impedance measurements (1 Hz–100 kHz) were collected from yeast cultures across log-phase development. Engineered features—derived from impedance magnitude and phase—captured dielectric and conductive shifts associated with cell proliferation, membrane polarization, and ionic redistribution. A Gaussian Process Regression model trained on these features predicted optical density (OD600) with high precision (RMSE = 0.79 min; R² = 0.9996; r = 0.9998), and achieved 100% classification accuracy when discretized into 15-min growth intervals. The system operated with sub-millisecond latency and minimal memory footprint, enabling embedded deployment. Benchmarking against conventional methods revealed superior throughput, automation potential, and independence from labeling or turbidity-based optics. This AI-driven platform forms the core of a real-time digital twin for yeast culture monitoring, capable of predictive tracking and adaptive control. By fusing electrochemical biosensing with machine learning, our method offers a scalable and robust solution for intelligent fermentation and bioprocess optimization. Full article

Aeromonas hydrophila is a typical pathogen that causes fish diseases and can easily infect different fish species. This study investigated the antibacterial activity, physicochemical properties and antibacterial mechanism of the BLIS UI-11 produced by Lactobacillus plantarum HYH-11, isolated from traditional kimchi in Hebei, China. It was found that BLIS UI-11 showed excellent inhibitory effect on the growth of A. hydrophila, and it also had a good antibacterial effect on various pathogens such as Vagococcus fluvialis, Listeria monocytogenes, Aeromonas dhakensis, Aeromonas salmonicida, Salmonella Typhimurium, Escherichia coli and Staphylococcus aureus. By measuring growth kinetics, it was found that the maximum antibacterial activity was reached after 30 h of culture, and both the optical density value at 600 nm (OD₆₀₀₎ and pH basically entered the stable phase after 20 h. Whole-genome analysis and gene cluster prediction identified a RiPP-like biosynthetic gene cluster, which comprises genes encoding precursor peptides, modification enzymes, and transport/immunity components. The molecular weight of the antimicrobial active substance was detected by dialysis and Tricine-SDS-PAGE, and it was shown to be an ultra-small molecular substance (<1 kDa). BLIS UI-11 was sensitive to protease K, but its antibacterial activity remained stable after treatment with acidic environment (pH 3.0–6.0), high-temperature treatment (121 °C for 30 min), and ultraviolet irradiation (4 h). After the sub-live cell assay (PI/SYTO9) and scanning electron microscopy (SEM), BLIS UI-11 inhibited the growth of bacteria by destroying the cell membrane of A. hydrophila to deform, collapse, and form holes that lead to accounting leakage. The hemolysis assay indicated that BLIS UI-11 exhibited incomplete hemolysis, suggesting its safety for application. The results showed that BLIS UI-11 produced by strain HYH-11 has great potential as an antimicrobial agent against A. hydrophila infection. Full article

Optimizing nutrient formulations is essential to improving the biomass yield and C-phycocyanin (C-PC) productivity of Spirulina sp., a cyanobacterium with wide-ranging applications in food, pharmaceutical, and biotechnological industries. This study evaluated the effects of macronutrient modifications on growth and pigment biosynthesis using a two-level full factorial design across eight Zarrouk-based formulations compared to the standard medium. Cultivation experiments were conducted in triplicate, and growth was evaluated using linear growth rate, maximum optical density (OD₆₈₀), and dry biomass, while C-PC was quantified in crude extracts (PCL), dried biomass (PCD), and the purity index (PI). Among the tested formulations, F2 (16 g/L NaHCO₃, 5 g/L NaNO₃, 0.25 g/L K₂HPO₄) achieved the highest biomass productivity, yielding a 37.6% increase in dry weight and a 38.1% improvement in daily productivity compared to the control. In contrast, F3 (16 g/L NaHCO₃, 5 g/L NaNO₃, 1 g/L K₂HPO₄) yielded the highest C-PC content, nearly doubling both PCL and PCD values and enhancing pigment purity by 40.2%. ANOVA and interaction analyses confirmed that carbon and nitrogen synergistically promoted biomass formation, while phosphorus had a strong effect on pigment biosynthesis through C:N:P interactions. These findings demonstrate that Spirulina sp. requires distinct nutrient balances for optimal growth and pigment formation. Formulation F2 is ideal for maximizing biomass productivity, whereas F3 is optimal for high-value C-PC production. The results provide a rational framework for designing nutrient-efficient cultivation systems to advance sustainable Spirulina-based biomanufacturing. Full article

The many uses of biochar extend to microbial enhancement in fermentation processes because it acts as a catalyst and a support medium in agricultural industries, particularly for biofertilizer production. This study explores how three key biochar parameters, concentration (0.05–0.25% w/v), temperature (30–50 °C), and particle size (250 μm–1.40 mm) affect hyper-ammonia-producing bacteria (HAB) growth during fermentation using commercially sourced pine wood-derived biochar. Fermentation experiments utilized enriched cow rumen fluid under controlled conditions, monitoring bacterial growth via optical density (OD₆₀₀) over 48 h. Microbial proliferation was strongly influenced by all tested parameters (concentration, temperature, particle size). Highest growth occurred at 0.15% biochar concentration, 45 °C, and 250 μm particle size within the tested parameter ranges. Lower concentrations and smaller particles promoted microbial adhesion and colonization. Higher biochar levels hindered growth due to surface saturation and reduced pore accessibility. SEM imaging supported these findings by revealing structural changes on the biochar surface at different concentrations. Regression analysis demonstrated strong correlation between biochar parameters and microbial activity (R² = 0.9931), though multicollinearity limited individual variable significance. These findings support biochar optimization for enhanced microbial processing in biotechnological applications. Full article

Introduction: 5-HMF is a molecule found in carbohydrate-rich foods that is associated not only with cancer and anaphylactic reactions, but also with anti-oxidant properties. Questions arose as to whether 5-HMF exhibited a catalytic effect in relation to lipid peroxidation and lipoprotein oxidation in presence of metals and/or radicals. Methods: Peroxynitrite (ONOO⁻)-induced chemiluminescence and ONOO⁻ nitration of tyrosine residues on BSA using anti-nitro-tyrosine-antibodies were used to measure the protection of 5-HMF against peroxides or nitration compared to vitamin C (VitC). The reductive potential of 5-HMF or VitC on Cu²⁺ or Fe³ was estimated using the bicinchoninic acid (BCA) or Fenton-complex method. Human plasma was used to measure the generation of malondialdehyde (MDA), 4-hydroxynonenal (HNE), and total thiols after Fe²⁺/H₂O₂ oxidation in the presence of different concentrations of 5-HMF or VitC. Finally, Cu²⁺ oxidation of LDL after 4 h was carried out with 5-HMF or VitC, measuring the concentration of MDA in LDL with the thiobarbituric assay (TBARS). Results: VitC was 4-fold more effective than 5-HMF in scavenging ONOO⁻ to nearly 91.5% at 4 mM, with the exception of 0.16 mM, where the reduction of ONOO⁻ by VitC was 3.3-fold weaker compared to 0.16 mM 5-HMF. VitC or 5-HMF at a concentration of 6 mM inhibited the nitration of tyrosine residues on BSA to nearly 90% with a similar course. While 5-HMF reduced free Fe³⁺ in presence of phenanthroline, forming Fe²⁺ (phenantroleine)₃ [Fe²⁺(phe)₃] or complexed Cu²⁺(BCA)₄ to Cu⁺(BCA)₄ weakly, VitC was 7- to 19-fold effective in doing so over all the used concentrations (0–25 mM). A Fe²⁺—H₂O₂ solution mixed with human plasma showed a 6–10 times higher optical density (OD) of MDA or HNE in the presence of 5-HMF compared to VitC. The level of thiols was significantly decreased in the presence of higher VitC levels (1 mM: 198.4 ± 7.7 µM; 2 mM: 160.0 ± 13.4 µM) compared to equal 5-HMF amounts (2562 ± 7.8 µM or 242.4 ± 2.5 µM), whereas the usage of lower levels at 0.25 µM 5-HMF resulted in a significant decrease in thiols (272.4 ± 4.0 µM) compared to VitC (312.3 ± 19.7 µM). Both VitC and 5-HMF accelerated copper-mediated oxidation of LDL equally: while the TBARS levels from 4 h oxidized LDL reached 137.7 ± 12.3 nmol/mg, it was 1.7-fold higher using 6 mM VitC (259.9 ± 10.4 nmol/mg) or 6 mM 5-HMF (239.3 ± 10.2 nmol/mg). Conclusions: 5-HMF appeared to have more pro-oxidative potential compared to VitC by causing lipid peroxidation as well as protein oxidation. Full article

Cocultivation of microalgae and aerobic methanotrophs represents an emerging biotechnology platform to produce high-protein biomass, yet quantifying individual species in mixed cultures remains challenging. Here, we present a rapid, low-cost method—differential sedimentation, optical density, and fluorescence (DSOF)—to determine the abundance of coculture members. DSOF exploits differences in cell size and pigment autofluorescence between the thermoacidophilic microalga and methanotrophic species Galdieria sp. RTK37.1 and Methylacidiphilum sp. RTK17.1, respectively, to selectively sediment algal cells and estimate population contributions via OD₆₀₀ and phycocyanin fluorescence. Evaluation with model suspensions across a wide cell density range (0 ≤ [Galdieria]: ≤ 3.23 A.U., and 0 ≤ [Methylacidiphilum] ≤ 1.54 A.U.) showed strong agreement with known values, with most absolute errors < 0.1 A.U. and relative errors < 10% at moderate biomass levels. Application to live batch cocultures under microalga or methanotroph growth-suppressed conditions, and during simultaneous growth, demonstrated accurate tracking of population dynamics and revealed enhanced methanotroph growth in the presence of oxygenic microalgae. While DSOF accuracy decreases at very concentrated biomass (>2.0 A.U. for Galdieria) or under nitrogen-limiting conditions, the model provides a practical, scalable alternative to more complex, invasive or expensive techniques, enabling near real-time monitoring of microalgae–methanotroph cocultures. Full article

Welsh onion (Allium fistulosum L.), a globally significant vegetable, flavoring agent, and phytomedicine resource, has remained unavailable with established transient expression platforms for functional genomic investigations. To address this critical methodological limitation, we present systematically optimized protocols for both Agrobacterium-mediated hairy root transformation and protoplast transient expression systems, achieving significant advances in transformation efficiency for this species. Through systematic optimization of key parameters, including Agrobacterium rhizogenes (A. rhizogenes) strain selection (with Ar.Qual demonstrating superior performance), explant type efficacy, bacterial suspension optical density (OD₆₀₀ = 0.3), and acetosyringone induction concentration (100 μM), we established a highly efficient stem disc infection methodology, achieving 88.75% hairy root induction efficiency. Subsequent optimization of protoplast isolation protocols identified the optimal enzymatic digestion conditions: 6-h dark digestion of young leaves using 1.0% (w/v) Cellulase R-10, 0.7% (w/v) Macerozyme R-10, and 0.4 M mannitol, yielding 3.3 × 10⁶ viable protoplasts g⁻¹ FW with 90% viability. System functionality validation through PEG-mediated transient transformation demonstrated successful green fluorescent protein (GFP) reporter gene expression, confirmed by fluorescence microscopy. As the first documented transient expression platforms for Welsh onion, these protocols enable essential molecular investigations, including in planta promoter activity profiling, subcellular protein localization, and CRISPR-based genome-editing validation. This methodological breakthrough overcomes previous technical constraints in Welsh onion molecular biology, providing critical tools for accelerated gene functional characterization in this agriculturally important species. Full article

Urban wastewater is composed of nutrients such as nitrogen and phosphorus, organic matter, heavy metals, pathogens, and micropollutants. If untreated, these contribute to eutrophication and environmental degradation. Microalgae-based bioremediation offers a sustainable solution, showing promise for pollutant removal and high-value bioproduct generation. This study evaluates the efficacy of Galdieria sulphuraria ACUF 427 in treating urban wastewater, with a focus on nutrient removal and phycocyanin production at different optical densities (OD 2, OD 4, and OD 6). Nutrient removal rates (RRs) were analysed for ammonium nitrogen (N-NH₄⁺), ammonia nitrogen (N-NH₃), phosphate phosphorus (P-PO₄³⁻), and chemical oxygen demand (COD). The RR for N-NH₄⁺ increased with optical density, reaching 7.49 mg/L/d at an optical density of 6. Similar trends were observed for N-NH₃ and P-PO₄³⁻, with peak removal at OD 6. COD removal remained high across all ODs, though differences between OD 4 and OD 6 were not statistically significant. Significant variations (p < 0.05) in nutrient removal were noted across the ODs, except for COD between OD 4 and OD 6. Biomass growth and phycocyanin production were significantly higher in the wastewater compared to the control (Allen Medium), with the most effective performance observed at an optical density (OD) of 6. Maximum growth rates were 0.241 g/L/d at OD 6, 0.178 g/L/d at OD 4, and 0.120 g/L/d at OD 2. These results highlight the potential of G. sulphuraria as an agent for wastewater bioremediation and the production of high-value compounds, particularly at elevated cell densities, where we achieved superior nutrient removal and biomass production. Full article

Hospital-acquired infections (HAIs) remain a major clinical and economic burden, with pathogens such as Escherichia coli contributing to high rates of morbidity and mortality. Traditional manual disinfection methods are often insufficient, particularly in high-risk hospital environments. In this study, we investigated innovative strategies to enhance surface decontamination and reduce infection risk. First, we assessed the efficacy of the SMEG BPW1260 bedpan washer-disinfector, a thermal disinfection system for human waste containers. Our results demonstrated a reduction in Clostridium difficile and Escherichia coli contamination by >99.9% (>3 log reduction), as measured by colony-forming units (CFU) before and after treatment. Molecular techniques, including spectrophotometry, cell counting, and quantitative PCR (qPCR) for DNA quantification, confirmed reduction in bacterial contamination. Specifically, Clostridium difficile showed a reduction of approximately 89% in both optical density (OD) and cell count (cells/mL). In the case of Escherichia coli, a reduction of around 82% in OD was observed, with an even more pronounced decrease in cell count, reaching approximately 99.3%. For both bacteria, DNA quantification by qPCR was below detectable limits. Furthermore, we optimized the energy efficiency of the disinfection cycle, achieving a 45% reduction in power consumption compared to standard protocols without compromising antimicrobial efficacy. Secondly, we developed a sustainable cleaning solution based on methyl ester sulfonate surfactants derived from waste cooking oil. The detergent’s antibacterial activity was tested on contaminated surfaces and further enhanced through the incorporation of nanoassemblies composed of silver, electrostatically bound either to biomimetic magnetic nanoparticles or to conventional magnetic nanoparticles. Washing with the detergent alone effectively eliminated detectable contamination, while the addition of nanoparticles inhibited bacterial regrowth. Antimicrobial testing against E. coli revealed that the nanoparticle-enriched formulations reduced the average MIC values by approximately 50%, with MIC₅₀ values around 0.03–0.06 mg/mL and MIC₉₀ values between 0.06 and 0.12 mg/mL, indicating improved inhibitory efficacy. Finally, recognizing the infection risks associated with intra-hospital transport, we tested the SAFE-HUG Wheelchair Cover, a disposable non-woven barrier designed to reduce patient exposure to contaminated wheelchair surfaces. Use of the cover resulted in a 3.3 log reduction in surface contamination, based on viable cell counts. Optical density and bacterial DNA were undetectable in all covered samples at both 1 and 24 h, confirming the strong barrier effect. Together, these approaches—thermal no-touch disinfection, eco-friendly detergent boosted with nanoparticles, and protective transport barriers—respond to the urgent need for effective, sustainable infection control methods in healthcare settings. Our findings demonstrate the potential of these systems to counteract microbial contamination while minimizing environmental impact, offering promising solutions for the future of infection prevention in healthcare settings. Full article

Researchers traditionally calculate growth rates using the natural logarithm of optical density (OD), with existing script packages facilitating this process. Automatic plate readers, capable of simultaneously measuring OD across 384 cultures, significantly enhance data collection efficiency. Furthermore, these readers also measure luminescence and fluorescence, providing valuable insights into gene expression. However, current analysis software often struggle with data generated by robotic systems measuring multiple plates, limiting the integration of growth and reporter analyses. This method paper addresses three key challenges: (a) the incompatibility of robotic multi-plate systems with existing analysis software, (b) the integration of growth and reporter analyses, and (c) the development of user-friendly interfaces for non-programmers. To address these challenges, we offer optimized script packages and a relevant case study on matrix expression in response to antibiotics. Our platform facilitates the efficient and integrated analysis of multi-plate growth and reporter data. Full article

Bioactive glass materials have been used for decades in orthopedic surgery, traumatology, and oral and maxillofacial surgery to repair bone defects. This study aimed to evaluate in vitro the survival and proliferation of MG63 human osteosarcoma-derived cells on S53P4 bioactive glass (BonAlive^® granules). Microscopic visualization was performed to directly observe the interactions between the cells and the material. Osteoblast-like cells were examined on non-adherent test plates, on tissue culture (TC)-treated plates and on the surface of the bioglass to assess the differences. Cell survival and proliferation were monitored using a CCK-8 optical density assay. Comparing the mean OD of MG63 cells in MEM on TC-treated plates with cells on BG, we detected a significant difference (p < 0.05), over each time of observation. The sustained cell proliferation confirmed the non-cytotoxic property of the bioglass, as the cell number increased continuously at 48, 72, 96, and 168 h and even did not plateau after 168 h. Since the properties of bioglasses can vary significantly depending on their composition and environment, a thorough characterization of their biocompatibility is crucial to ensure their effective and appropriate application—for example, during hip and knee prosthesis insertion. Full article