Search Results (207)

Hydrogen (H₂) is a promising renewable energy carrier because of its high energy density and environmentally friendly characteristics. The halotolerant cyanobacterium Aphanothece halophytica is a potential biological H₂ producer because of its ability to generate H₂ via oxygen-sensitive hydrogenase activity under nitrogen-deprived dark anaerobic conditions. This study investigated the effects of various chemical supplements on H₂ production by A. halophytica. Initial screening identified glucose, sodium dithionite, and dithiothreitol (DTT) as effective stimulants for enhancing H₂ production. Optimization experiments established 10 mM glucose, 5 mM DTT, and 1 mM sodium dithionite as the optimal concentrations for H₂ production. Combined supplementation under these optimized conditions resulted in the highest H₂ production rate of 0.588 ± 0.028 mL·L⁻¹·h⁻¹ and maximum cumulative H₂ yield of 8.445 ± 0.750 mL·L⁻¹ after incubation for 72 h, representing increases of approximately 170–180%, compared with the untreated control. Simultaneously, maximum cumulative O₂ production decreased from 20.176 ± 0.850 to 10.405 ± 0.480 mL·L⁻¹, corresponding to approximately a 50% reduction. These findings demonstrate that simultaneous optimization of electron supply, oxygen minimization, and intracellular redox balance using selected stimulants effectively enhances H₂ production by A. halophytica, providing a simple and practical strategy for improving biological H₂ production. Full article

Green synthesis has emerged as a sustainable alternative to conventional nanoparticle production by utilizing biological resources as reducing and stabilizing agents. In this study, extracts of Chlorella vulgaris cultured at different incubation temperatures and light periods were evaluated for their total phenolic content, total flavonoid content, and antioxidant capacity to identify the most suitable extract for the green synthesis of zirconium dioxide (ZrO₂) nanoparticles. The extract prepared at 25 °C under a 12 h light/12 h dark photoperiod exhibited the highest antioxidant activity and flavonoid content and was selected for nanoparticle synthesis. ZrO₂ nanoparticles were successfully synthesized using a green approach and characterized by dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-Ray diffraction (XRD). DLS analysis revealed hydrodynamic particle sizes ranging from 419 to 570 nm with polydispersity index values between 0.27 and 0.44. FTIR analysis confirmed the formation of ZrO₂ through characteristic Zr–O and Zr–O–Zr vibrational bands, while SEM images demonstrated predominantly spherical particles with a heterogeneous size distribution. The synthesized nanoparticles retained considerable phenolic and flavonoid contents and exhibited enhanced antioxidant activity compared with the corresponding algal extracts. Furthermore, the nanoparticles demonstrated broad-spectrum antibacterial activity against both Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria, as well as antifungal activity against Candida albicans and Saccharomyces cerevisiae. Nanoparticles synthesized by incubation at 40 °C for 12 h showed the strongest antimicrobial activity. These findings demonstrate that cultivation conditions of C. vulgaris and the synthesis conditions of the nanoparticles significantly influence nanoparticle properties and biological activity, highlighting the potential of microalgae-mediated green synthesis for developing environmentally friendly antimicrobial nanomaterials. Full article

The valorization of food industry by-products is a promising strategy for developing natural additives to increase food quality. This study examined the efficiency of tomato processing industry waste (TPIW), which is a significant agro-industrial by-product, in enhancing the oxidative stability of three common edible vegetable seed oils (i.e., sunflower, soybean, and corn oils) under accelerated storage conditions. A custom response surface methodology (RSM) approach was employed to design and optimize the experiments, also using butylated hydroxytoluene (BHT), a potent synthetic antioxidant (i.e., oil type, TPIW and/or BHT enrichment). Oils were incubated under controlled conditions at 60 °C for 28 d (Schall oven test), wherein both darkness and light exposure were employed. Untreated (control), TPIW-enriched, and BHT-fortified (positive control) oils were examined in this study. The oxidative stability and shelf-life of oils was thoroughly evaluated using standard oxidative indices for both primary and secondary oxidation by-products, antioxidant capacity (DPPH radical scavenging activity), total carotenoid content, chromatic coordinates (CIE 1976 L*a*b*), and Fourier-Transform Infrared spectroscopy to monitor structural changes. The results revealed that enrichment with TPIW significantly (p < 0.05) reduced both primary and secondary oxidation products compared to untreated oils, approaching the protective efficiency of BHT in some assays. Specifically, it was observed that the combination of soybean oil enriched with both BHT and TPIW was the most preferable to enhance oxidation stability. Results from FT-IR supported these findings; slower formation of oxidative derivatives was revealed. Light exposure did not show a significant impact on the oxidation process regardless of the oil sample when compared to the temperature parameter. The results of this study confirm that TPIW could assist shelf-life prolongation of edible vegetable oils and promote a circular economy strategy by valorizing food by-products as a viable alternative to synthetic antioxidants. Full article

This study optimised and validated a microplate Ferric-Reducing Antioxidant Power (FRAP) assay for honey that incorporates a honey-specific matrix-matched blank—a paired absorbance measurement lacking the chromogenic probe 2,4,6-tris(2-pyridyl)-s-triazine (TPTZ)—to separate true ferric reduction from non-reductive Fe³⁺–matrix interactions that otherwise inflate apparent antioxidant capacity. A 30 min incubation at 37 °C in the dark was selected as the optimal compromise between reaction completeness and reagent/matrix stability, using 20 µL sample and 180 µL FRAP reagent per well (absorbance at 620 nm). The assay was validated according to International Council for Harmonisation (ICH) principles, showing linearity for FeSO₄·7H₂O from 200–1200 µM (R² ≥ 0.9988), Limit of detection/limit of quantification (LOD/LOQ) of 0.28/0.94 mmol Fe²⁺ equivalents kg⁻¹, recoveries of 101–103%, and precision ≤ 5% relative standard deviation (RSD). All tested individual sugars except maltodextrin and the artificial honey matrix produced FRAP responses below the LOQ. Flavonoids, however, showed pronounced, time-dependent, non-reductive Fe³⁺ interactions and were markedly overestimated under conventional water blanking, while phenolic acids were less affected. Applied to 47 Western Australian honeys, the validated assay yielded FRAP activities of 2.80–9.52 mmol Fe²⁺ kg⁻¹; matrix-matched blanking gave consistently lower, more chemically specific values than conventional water blanking, with corrections ranging up to >30% depending on honey type. Matrix-matched blanking is therefore essential, not optional, for accurate FRAP measurement in honey, and the same principle should apply directly to other phenolic-rich foods like wine, tea, and fruit extracts—wherever iron–polyphenol interactions confound conventional antioxidant assays. Full article

Sugarcane (Saccharum spp. hybrid) is the most important sugar crop. However, its genetic improvement is severely constrained by genotype-dependent regeneration recalcitrance and lengthy tissue culture cycles. Here, we established a simple, efficient, and genotype-flexible in planta transformation system using two-leaf-stage plantlets. By systematic optimization of three key parameters: Agrobacterium cell density (OD₆₀₀ = 0.5), dark incubation duration (2 weeks), and infection frequency (two rounds), we achieved a maximum transformation efficiency of 51.2%. The protocol was successfully applied to eight diverse sugarcane varieties, with transformation efficiencies ranging from 33.3% to 51.2%, demonstrating broad genotype applicability. Using this optimized system, we introduced Sh4CL13 into sugarcane. Transgenic lines exhibited a 3.25-fold increase in Sh4CL13 transcript levels and a 13.7-fold elevation in chlorogenic acid (CGA) content compared to controls. Feeding bioassays with Mythimna separata larvae revealed that transgenic lines significantly prolonged larval developmental duration, reduced pupal weight, and decreased adult emergence rates. This in planta transformation system bypasses tissue culture, offers a practical platform for functional genomics and molecular breeding in sugarcane and potentially other monocot crops. Full article

This study aimed to establish and optimize an open in-bottle micro-cutting technique for Taxus × media. An orthogonal experimental design was adopted. Four core factors were optimized: light regime, plant growth regulator (PGR) type, PGR concentration, and PGR soaking time. Analysis of variance (ANOVA) and Duncan’s multiple-range test were performed to analyze the statistical significance of each factor. The optimal combination was identified. Branches were soaked in a 300 mg·L⁻¹ IBA solution for 15 min. They were then cultured under 12 h alternating light/dark conditions in an illumination incubator. Under these conditions, the cutting rooting rate reached a maximum of 45.83%. The optimized open tissue culture system established in this study provides reliable technical support for the clonal propagation of T. × media. Full article

Background/Objectives: This study investigated the effects of different roasting levels on bound phenolic composition and antioxidant activity in barley malts. Methods: Bound phenolics from raw, fried, and dark malts were characterized using UPLC-Q-Orbitrap HRMS/MS combined with multivariate analysis. Potential antioxidant-active compounds were screened by DPPH/AAPH-incubating UPLC-DAD and further evaluated by in vitro antioxidant assays. Results: A total of 44 bound phenolic compounds were tentatively characterized. Distinct differences in bound phenolic profiles were observed among the three malts, with raw malt exhibiting relatively higher levels of bound phenolics. PCA analysis revealed compositional differences among samples. Activity-guided screening identified epicatechin gallate, trans-ferulic acid, and cis-ferulic acid as compounds exhibiting pronounced radical-scavenging activity, which was further supported by in vitro assays. Conclusions: Different roasting levels were associated with changes in bound phenolic composition and antioxidant properties of barley malts, providing insights into the relationship between thermal processing and the functional quality of malt-based products. Full article

The disinfection process in wastewater treatment is key to the discharge and/or reuse of high-quality effluent. However, disinfection using ultraviolet (UV) light may be inefficient because bacteria possess mechanisms for repairing damaged DNA. This study aimed to assess the photoreactivation and dark repair of total coliform (TC) in wastewater effluent after UV-C disinfection treatment. Four UV-C doses (28.8, 53.1, 57.6, and 106.2 mJ/cm²) and two post-irradiation conditions (light vs. darkness) were applied. Reactivation was monitored after 2, 4, 6 and 24 h (25 °C). Similar TC inactivation efficiencies were observed for the three lowest UV-C doses, whereas the 106.2 mJ/cm² dose achieved the greatest reduction (1.1 Log of TC), decreasing TC concentrations from 3.1 × 10⁵ ± 3.5 × 10⁵ to 1.2 × 10⁵ ± 1.4 × 10⁵ MPN/100 mL. Reactivation assays revealed substantial bacterial recovery after UV treatment, with 24 h survival rates up to 2.3 × 10³ under light and 9.2 × 10² in darkness. Photoreactivation and dark repair assays revealed substantial variability in bacterial recovery after UV treatment depending on UV-C dose, post-irradiation condition and incubation time. In general, bacterial recovery was still detected even at the 106.2 mJ/cm² dose, particularly after 24 h of incubation (178–604%). These findings suggest that effective organic matter removal before UV-C disinfection is critical to improve UV transmittance, reduce shielding effects, and limit subsequent bacterial recovery. Full article

The expression of two genes, Fum1 and Fum2, encoding the mitochondrial and cytosolic forms of fumarase (EC 4.2.1.2); the methylation of individual CpGs of their promoters; and fumarase activity were studied in sunflower (Helianthus annuus L.) leaves depending on irradiation and salinity. Fumarase activity was twice as high in darkness compared to irradiation by white light and red light, while far-red light applied after darkness or after red light reverted the activity to the values in darkness, which indicates the involvement of phytochrome. Using qRT-PCR, it was demonstrated that this corresponded to the pattern of expression of the Fum1 gene, while the expression of the Fum2 gene was higher upon irradiation by white and red light, and lower in darkness and under far-red light. Under the application of 150 mM NaCl for 1, 3, 6, 12, and 24 h, fumarase activity increased fivefold from the start of incubation to 6 h, and then decreased after 12 h. These changes were associated with the transcriptional regulation of the Fum1 and Fum2 genes. Changes in the methylation status of the analyzed CpGs in their gene promoters, detected via semi-quantitative methylation-specific PCR, were associated with differences in their expression. The higher methylation levels of the analyzed CpGs in the Fum1 gene promoter under different light conditions and in the Fum2 gene promoter under salinity corresponded to low levels of their transcripts in sunflower leaves. It is suggested that the mitochondrial and cytosolic forms of fumarase are regulated by light and salinity at the gene expression level, presumably through changes in the methylation status of individual CpGs in their promoters. Full article

Aspergillus flavus is a globally distributed filamentous fungus of major agricultural and medical importance, capable of producing carcinogenic aflatoxins and forming two specialized developmental structures, conidia and sclerotia. While the molecular framework governing conidiation has been well characterized in Aspergillus nidulans, the corresponding mechanisms in A. flavus remain somewhat unelucidated. In this study, we identified and functionally characterized AfldrnA, a gene encoding a basic helix–loop–helix (bHLH) transcription factor. Targeted deletion of AfldrnA resulted in an aconidial phenotype accompanied by a significant increase in sclerotia formation, whereas complementation with the intact AfldrnA gene restored conidiation and reduced sclerotia development. Phenotypic assays revealed that the ΔAfldrnA mutant exhibited normal vegetative growth, unchanged antifungal susceptibility, and unaffected aflatoxin B₁ production, indicating that AfldrnA primarily regulates developmental rather than metabolic differentiation. Additionally, observed differences between standard and dark incubation conditions suggest that AfldrnA may be involved in environmentally responsive regulation of fungal development. Overall, this study identifies AfldrnA as a pivotal transcriptional regulator essential for coordinating conidiation and sclerotia formation in A. flavus, providing new insights into the genetic and environmental regulation of fungal developmental programs. Full article

The antimicrobial activity of multicomponent, magnetron-sputtered glass coatings was evaluated against phytopathogenic fungi (Botrytis cinerea, Fusarium oxysporum, Cladosporium fulvum, Alternaria solani) and the chromista Phytophthora infestans, with Aspergillus fumigatus included as a model opportunistic pathogen. Fourteen Cu-based multicomponent coatings were deposited on glass using multi-alloy targets composed of Sn, Zn, Al, Ni, Fe, Ti, Mn, Nb, or Co in two high-transmittance variants (≥85% and ≥88%). Antimicrobial activity was assessed in two assays: (A) spore survival after 24–72 h contact, and (B) hyphal growth over 7 days following coating exposure under light and dark conditions. Spore viability decreased after incubation on high-Cu coatings, which showed inhibition for most strains, particularly B. cinerea, F. oxysporum, and P. infestans. The effects on spore germination were independent of the direct transmittance value of the coated glass. Hyphal growth was generally less affected by a high Cu content for most strains. Hyphal growth of F. oxysporum, C. fulvum, A. solani and B. cinerea was reduced by up to 30% on selected multicomponent coatings. For most strains, hyphal growth showed no inhibition after light incubation on coatings. However, light-dependent effects were observed for A. solani, A. fumigatus and P. infestans, while B. cinerea and C. fulvum showed reduced sensitivity during the first two days. High-Cu coatings were most effective at inhibiting spore germination, whereas hyphal growth on multicomponent coatings may respond to different ions. Therefore, high-Cu, two-component coatings may be recommended for practical greenhouse applications. Full article

Background and Clinical Significance: Cladosporium cladosporioides is a ubiquitous dematiaceous mold that is rarely implicated in invasive human diseases and often considered a saprophyte and plant pathogen. Case Presentation: We report an extremely rare case of C. cladosporioides fungemia in a 61-year-old man with mantle cell lymphoma undergoing chemotherapy. The patient developed fever, dry cough and cavitary pulmonary lesions in the setting of profound immunosuppression. Blood cultures yielded slow-growing dark pigmented mold after prolonged incubation and species identification was achieved using MALDI-TOF mass spectrometry with an alternative fungal database, supported by microscopic morphology. Serum 1,3-β-D-glucan levels were markedly elevated, while galactomannan antigen testing was negative. Antifungal susceptibility testing demonstrated activity of triazoles and targeted therapy with voriconazole led to clinical improvement. A review of the literature identified only five previously reported cases of invasive C. cladosporioides infections worldwide, involving primarily pulmonary and central nervous system disease. Conclusions: To the best of our knowledge, this is the first documented case of fungemia caused by this species. The current report highlights the pathogenic potential of C. cladosporioides in immunocompromised hosts, the diagnostic challenges posed by slow-growing dematiaceous fungi, the importance of prolonged culture incubation, fungal biomarkers and advanced identification techniques for timely diagnosis and management. Full article

The light spectrum is a key factor in aquaculture, but its effects on molecular stress responses during early fish development are unclear. This study examined how light of different wavelengths (spectra) affects embryos of Baikal whitefish Coregonus baicalensis and its hybrid with Yenisei hump-snout whitefish C. fluviatilis. Eggs were incubated from 35 days post-fertilization under white light (1.8 and 20 µmol m⁻² s⁻¹), darkness, red (peak at 631 nm), green (peak at 507 nm) and blue (peak at 459 nm) light. We analyzed relative telomere length, telomerase activity, blood profiles, and expression of stress-related genes (HSP-90, MtCK) at key developmental stages. Notably, a significant increase in telomere length was observed throughout early development (from embryo to larva to fry), independent of the light spectrum. Red light and darkness acted as potent stressors, indicating proteotoxic stress and energy imbalance. In Baikal whitefish, this was accompanied by notable telomere shortening at the earliest stage and elongation at later stages under certain conditions, potentially mediated by increased telomerase activity, a response that may be metabolically costly. Conversely, green light was the most neutral. The effect of blue light differed between Baikal whitefish and its hybrid, with the hybrid proving more sensitive. Furthermore, high-intensity white light (20 µmol m⁻² s⁻¹) also induced negative effects in the hybrid, such as increased telomere length, suggesting that excessive irradiance itself can be a stressor, independent of spectral composition. We conclude that darkness or a predominance of red light is suboptimal for incubating these whitefish, while green light provides a more favorable environment, offering a basis for optimizing aquaculture light conditions. Full article

Wheat and rice are major sources of human nutrition worldwide. Solid-state fermentation (SSF) with lignocellulolytic mushrooms can enhance their nutritional value and increase their functional properties. However, this technology is not yet widely applied. In this work, whole wheat and brown rice hydrated to 60% were used as substrates for the edible mushroom Pleurotus ostreatus and the medicinal Ganoderma sessile, which were incubated for 14 days at 25 °C in the dark. The fermented substrate biomass was incorporated into standard sugar-snap cookie recipes, substituting 20% of the wheat flour. We evaluated the technological and nutritional properties of alternative fermented flours and cookies. Both the fermented flours and cookies exhibited increased soluble and total protein content, antioxidant power, and phenol content, indicating overall functional improvement. Fermented G. sessile flour also showed increased triterpenoid content. The physical quality of cookies remained within expected ranges, demonstrating the feasibility of the application. These results highlight the potential of SSF as a method for nutritional and functional enrichment of grains and extend the health benefits of mushrooms to populations relying on low-cost, grain-derived carbohydrates. Further studies on digestibility and in vivo activity of metabolites are needed to confirm the potential health benefits of fermented flours. Full article

Background: Hypericin is a natural photosensitizer with promising antifungal potential, but its uptake kinetics in Candida (C.) albicans are not well defined. Objective: To characterize the time-dependent uptake of hypericin by C. albicans in vitro using fluorescence microscopy and quantitative image analysis. Methods: C. albicans ATCC 90028 was standardized to 0.5 McFarland and incubated with hypericin dissolved in DMSO. Samples were illuminated with an LED system tuned near 550 nm and imaged using a CCD fluorescence microscope with emission recorded above ≈600 nm. Images were analyzed in ImageJ, using a control-based threshold and percentage area (the percentage of pixels above the threshold in the whole field) as a fluorescence measure. Time points were 1, 3, 5, 7, 10, 15, 20, 25, 30, 35, 40, and 45 min, plus a separate dark-only series at 35–45 min. Data from three experiments were evaluated by ANOVA. Results: Fluorescence increased rapidly and showed a nonlinear, biphasic profile under light, with local maxima around 5–7 and 15–30 min. Dark-only samples at 35–45 min had a lower %Area and lacked a clear biphasic pattern. Conclusions: Hypericin uptake by C. albicans is dynamic, nonlinear, and light-dependent. These kinetics should be considered when designing hypericin-based antifungal photodynamic therapy protocols. Full article