Search Results (2,027)

The use of Kluyveromyces marxianus in mixed cultures for fermentation processes has become increasingly relevant. This yeast is characterized by rapid growth, thermotolerance, broad sugar utilization, and the ability to produce aroma-active compounds. In this study, we evaluated changes in the growth and volatilome of a K. marxianus strain isolated from agave fermentation under microbial competition induced by co-cultivation interactions and nutritional limitation induced by a nutrient-deficient medium. The results indicate that these stress factors are significant drivers of metabolic changes, leading to substantial increases in the concentrations of key aromatic compounds. Stress-free conditions favor cell growth and the production of stable, reproducible volatile profiles, which is advantageous for batch-to-batch consistency (as in wine or mezcal production). While microbial competition and nutritional limitation induce reduced cell growth and loss of viability, they also lead to increased aromatic diversity, particularly the synthesis of β-phenethyl acetate, ethyl octanoate, and ethyl hexanoate. These findings demonstrate a relationship between environmental stress and the development of volatile profile complexity, offering new insights into harnessing stress-induced changes in the volatilome to optimize the sensory profile of traditional fermentations. Full article

Taking 563 national key rural tourism villages across 12 provinces, autonomous regions, and municipalities in western China as the research object, this study integrates multi-source data on physical geography, transportation location, socioeconomic conditions, and historical culture based on the ArcGIS platform. It comprehensively applies kernel density analysis, spatial autocorrelation analysis, buffer analysis, Spearman correlation analysis, Geodetector, and the relative enrichment index to examine the spatial distribution characteristics of these villages and their associated spatial factors. The results show that key rural tourism villages in western China exhibit an overall clustered and uneven distribution, forming a spatial pattern characterized by “high concentration in core areas, extension along secondary corridors, and sparse distribution across vast hinterlands.” The core agglomeration areas are mainly located in the Sichuan Basin, the Chongqing metropolitan area, and the Guanzhong Plain. In terms of physical geography, the distribution of key villages shows certain spatial associations with major river basins, low-slope areas, and low-relief terrain. In terms of human factors, population density and road network density are important associated factors, and the combined population–transportation conditions have strong explanatory power for the spatial differentiation of key village density. With regard to historical culture, folk-custom inheritance villages and red-culture heritage villages account for relatively high proportions, while different cultural types show certain regional agglomeration or corridor-like distribution characteristics. The findings can provide references for zoned optimization, transportation connectivity, cultural resource integration, and coordinated regional development of key rural tourism villages in western China. Full article

Time-domain dynamic full-field optical coherence tomography (D-FFOCT) is a powerful label-free imaging modality that enables functional visualization of cellular activity in living tissues with subcellular resolution. However, its sensitivity remains a major limitation for imaging highly scattering three-dimensional (3D) biological models such as retinal organoids, where incoherent background and inefficient optical flux distribution reduce dynamic contrast and limit imaging depth. In this work, we introduce a ratio-free optical configuration for time-domain D-FFOCT that enables continuous tuning of the sample-to-reference field ratio while minimizing photon losses and suppressing parasitic reflections. This polarization-based architecture allows optimal redistribution of optical flux according to sample scattering conditions and improves sensitivity under both power-limited and dose-limited conditions. Compared with conventional non-polarizing beam splitter configurations, the proposed approach provides a $\sqrt{2}$-fold (3 dB) sensitivity improvement through optical optimization alone. In addition, we investigate for the first time the use of partial-field illumination (PFI) in time-domain D-FFOCT to reduce incoherent background arising from multiple scattering. In retinal organoids imaged at 120 $\mathsf{\mu }$m depth, PFI yields up to a 14.5-fold (23.2 dB) increase in dynamic signal sensitivity, while preserving functional contrast. When combined, ratio-free detection and PFI provide a cumulative sensitivity improvement of 20.5-fold (26.2 dB). These gains enable improved cellular-scale visualization in retinal organoids, including cell-resolved imaging within rosette regions, as well as improved detection of intracellular dynamics in Müller glial cell cultures. This work establishes a practical framework for sensitivity optimization in D-FFOCT and expands its potential for functional imaging, disease modeling, and live-cell monitoring in complex biological systems. Full article

To clarify the microbial contamination and wood degradation risk of the Nanhai No. 1 shipwreck hull and verify on-site antibacterial agent effectiveness, microbial samples were collected and analyzed via SEM, metagenomic sequencing, bacterial isolation, enzyme activity detection, and antibacterial experiments. The results showed that Actinomycetota was the dominant phylum, and Brachybacterium, Microbacterium, and Brevibacterium were the dominant genera. Seven bacterial strains were isolated and purified, among which Brevibacterium sp. (NH.SH-B6) had the strongest wood degradation ability, possessing cellulase, LiP, MnP, and Lac activities. When cultured with hull wood as the sole carbon source, LiP was the dominant degrading enzyme of NH.SH-B6, and its maximum enzyme activity was achieved under the optimal conditions of pH = 7, 10% NaCl, 1000 mg/L FeSO₄, and no PEG400 added. 50 mg/mL cinnamaldehyde and 0.5% isothiazolinone K100 had good inhibitory effects on the isolated bacteria, and bacterial proliferation was due to incomplete antibacterial agent spraying. This study clarifies the microbial degradation risk of the Nanhai No. 1 shipwreck hull and provides a scientific basis for optimizing the on-site protection strategy of the shipwreck. Full article

At present, treated wastewater may still contain residual nutrients and micropollutants, including heavy metals, pharmaceuticals, and dyes, which can negatively affect receiving water bodies. Increasingly stringent environmental regulations, including Directive (EU) 2024/3019, require both enhanced removal of these contaminants and greater integration of renewable energy sources in wastewater treatment plants. This paper presents a review of biomass-based wastewater polishing technologies employing biological agents such as microalgae, fungi, bacteria, co-cultures and duckweed for the removal of residual contaminants from treated effluents. The compiled data indicate that while optimal conditions can drive pollutant removal efficiencies beyond 90%, system performance varies widely depending on species selection, wastewater characteristics, and operational conditions (e.g., pH, temperature, salinity, nutrient availability, and light intensity). In addition to effluent polishing, the produced biomass can be valorized for bioenergy generation, contributing to renewable energy production and supporting circular economy principles in wastewater treatment plants. Despite these benefits, biomass harvesting remains a major technical and economic bottleneck, often representing a significant share of operational costs and limiting large-scale implementation. Overall, biomass-based treatment technologies are a promising approach for improving effluent quality and supporting renewable energy objectives; however, further advances in biomass recovery are required for broader application. Full article

This paper examines whether genuine dwelling—understood as embodied engagement with a world that resists, endures, and exceeds human control—can occur in the metaverse. Drawing on Heidegger’s account of dwelling and Ingold’s concept of the ‘taskscape’, it argues that the metaverse is structurally unable to sustain dwelling in the full ontological sense. The argument unfolds in three steps. First, dwelling is shown to depend on friction: bodily cost, temporal irreversibility, material resistance, and exposure to mortal finitude. Second, the metaverse is interpreted as a technological and commercial project oriented toward reducing these frictions through attenuated bodily burden, reversible action, programmable environments, and artificial scarcity. Third, the paper extends the concept of the metaverse beyond immersive hardware to describe a broader condition of digitalized life in which experience becomes increasingly modifiable, personalized, and optimized. In this wider sense, the difficulty of dwelling in the metaverse is not limited to a niche technology but reveals a tendency within late-digital culture itself. The paper concludes by proposing a politics of friction: a public deliberation over which resistances are unjust and should be transformed, and which are constitutive conditions of ethical, ecological, and responsible life. Full article

Light irradiance and spectral quality are key environmental factors that influence the growth, photosynthetic performance, and metabolic responses of cyanobacteria. In this study, the effects of increasing white and PAR-red light irradiances on Anabaena variabilis were evaluated in repeated-batch cultures, focusing on photosynthetic efficiency, biomass productivity, and the modulation of antioxidant systems, while cultures maintained under constant irradiance were used as control. Results showed that A. variabilis can maintain photosynthetic efficiency, as indicated by F_V/F_M values, within the optimal range for healthy cultures despite variations in light conditions. PAR-red light, in particular, enhanced biomass productivity and induced stronger photoacclimation responses compared to white light. Moreover, analysis of chlorophyll fluorescence (JIP parameters) revealed that photosynthetic machinery adapts to increased irradiance by modulating energy fluxes. Dissipated energy (DI₀/RC) increases by 4.5-fold under increasing PAR-red light with respect to control cultures, which suggests that PAR-red light promotes thermal dissipation of excess absorbed energy at the phycobilisome level, independently of and complementarily to, the increase in light-harvesting antenna pigments (chlorophylls and phycobiliproteins), thereby reducing the net oxidative pressure in the electron transport chain. The increase in photosynthetic pigments reflects an adaptive adjustment to optimize light harvesting under red light, with a phycocyanin content of 123 mg·g⁻¹ biomass, 30% higher than that obtained in control culture. Overall, A. variabilis demonstrated a robust capacity to acclimate increasing light irradiance and varying light quality through coordinated photoacclimation and antioxidant responses, in repeated-batch cultures. These findings highlight its physiological flexibility, which can be properly driven to maximize the production of valuable bioactive compounds, particularly phycobiliproteins such as phycocyanin, with applications in biotechnology. Full article

Background: Panvascular disease (PVD) is a systemic atherosclerotic condition that poses a substantial threat to global health. Despite the recognized importance of early proactive screening, proactive screening beliefs among high-risk populations are poorly understood. Objective: To explore the proactive screening beliefs among Chinese high-risk patients for PVD based on the Health Belief Model (HBM), so as to provide evidence for developing targeted nursing intervention strategies and health policies. Methods: A descriptive qualitative study was conducted. Employing a purposive sampling strategy with maximum variation, participants at elevated risk for PVD were recruited from a tertiary hospital in Shanghai between October and December 2025 to conduct semi-structured interviews. Data saturation guided sample size (n = 22; 14 male, 8 female; mean age 62.68 years). Data were analyzed using qualitative content analysis. Results: Five main themes were extracted: multifaceted perceptions of susceptibility, multidimensional fear of severity, positive attitudes toward the benefits of proactive screening, multiple perceived barriers to proactive screening, and significant differences in self-efficacy for proactive screening. Conclusions: The proactive screening beliefs in Chinese high-risk patients of PVD were deeply embedded in local cultural values and healthcare realities. Tailored health education, age-friendly service optimization, and stratified intervention strategies are urgently needed to reduce screening barriers and improve population-wide proactive screening beliefs. Full article

A newly isolated red-pigmented yeast, Sporobolomyces reniformis EMCC1691, was evaluated for its biotechnological potential in an integrated case study aimed at developing an efficient microbial cell factory for the valorization of delactosed whey. Fermentation trials in 5 L bioreactors demonstrated robust yeast growth on this dairy by-product, with complete consumption of glucose (21.86 g/L) and galactose (20.36 g/L), leading to the accumulation of approximately 6172 mg/L of lipids and 5634 µg/L of total carotenoids. Fatty acid analysis revealed a final concentration of 3924 mg/L, mainly represented by oleic (2037 mg/L), palmitic (779 mg/L), stearic (403 mg/L), and linoleic (362 mg/L) acids. HPLC analysis showed a pigment profile dominated by torularhodin, torulene, γ-carotene, and β-carotene. To complement downstream processing, the fermented culture was spray-dried into a stable powder and subsequently subjected to a simple, cost-effective, and unconventional mechanical pretreatment using a hydraulic press. This post-drying operation ensured extensive cell-wall disruption without the use of chemical agents or specialized equipment, thereby significantly enhancing the recoverability of intracellular lipids and carotenoids through supercritical CO₂ extraction. Under optimized conditions, SFE-CO₂ with ethanol recovered 92.18 ± 1.61 µg/g of total carotenoids, achieving an extraction efficiency of 84% relative to organic solvent extraction (109.17 ± 2.10 µg/g). Importantly, fermentation also reshaped the fatty acid composition of delactosed whey, shifting it toward a profile enriched in monounsaturated and polyunsaturated fatty acids, thereby further highlighting the metabolic impact and bioconversion potential of S. reniformis EMCC1691. Overall, this work highlights the technological relevance of a recently characterized yeast species and its potential to convert dairy by-products into high-value compounds within a proof-of-concept microbial cell factory framework, paving the way for future scale-up investigations. Full article

Introduction: The 3 Rs principle advocates developing alternative, biologically relevant models. Thus, 3D fish liver in vitro models have been increasingly used for ecotoxicological studies. We previously optimized spheroids from the rainbow trout non-tumoral liver cell line RTL-W1 and employed them to assess the effects of aquatic pollutants. Although they demonstrated potential for assessing ecotoxicological effects, further optimization is warranted to enhance their physiological relevance. Incorporating an extracellular matrix (ECM), such as collagen, has been shown to be a promising strategy to improve spheroids’ structural organization and functionality. Objective: This study aimed to optimize 3D culturing conditions of RTL-W1 spheroids by evaluating the effects of collagen supplementation on viability, morphology, and functional response. Methodology: Spheroids from the RTL-W1 cell line (60,000 cells per well) were cultured in 96-well ultra-low attachment (ULA) plates at 18 °C. After spheroids’ formation, rat tail collagen was supplemented at concentrations of 15 (C15), 30 (C30), and 60 (C60) µg/mL at culture days 7, 8, and 9. Spheroids were collected at two sampling days (10 and 14). Viability was assessed using alamarBlue and lactate dehydrogenase (LDH) assays, while morphology was assessed by optical microscopy. Collagen penetration was evaluated using Masson’s trichrome staining technique. Protein expression of cytochrome P450(CYP)1A was assessed by quantifying immunocytochemistry staining using an anti-CYP1A antibody. Results: On day 10, LDH leakage decreased in C15 and C60, compared with the control, whilst C15 spheroids showed lower absorbance levels in the alamarBlue assay. On day 14, LDH showed no significant differences; however, C30 and C60 had higher alamarBlue absorbance, indicating greater metabolic capacity. Spheroid morphology appeared intact in all conditions. Masson trichrome revealed collagen fibrils at the periphery of the spheroids, especially in C30 and C60, indicating that spheroids incorporated collagen. CYP1A immunostain was present in all conditions, localized in the spheroids’ border, and tended to be higher when supplementation occurred in earlier days. Conclusions: Our results suggest that RTL-W1 spheroids interacted with the collagen matrix and appeared to functionally improve. Data suggest that incorporating ECM may increase the complexity and physiological relevance of RTL-W1 spheroids, thereby better supporting mechanistic and ecotoxicological applications. Full article

iPSC technology is well established in mammals but remains underdeveloped in non-mammalian species. A major barrier to generating avian iPSCs has been the lack of species-specific reprogramming factors and culture conditions capable of supporting self-renewal in avian pluripotent stem cells. Here, we report the generation of chicken iPSCs (ciPSCs) using a cocktail of seven chicken transcription factors (T7: Oct4, Sox2, Sox3, Klf4, c-Myc, Nanog, and Lin28B) combined with an optimized avian culture system. Transcriptomic and functional analyses identified Sox3, rather than Sox2, as the predominant SoxB1 factor in avian reprogramming. The resulting ciPSCs exhibited stable self-renewal for over 40 passages, expressed core pluripotency markers, differentiated into all three germ layers, and were transcriptionally similar to chicken ESCs. In chimera assays, ciPSCs contributed to somatic, extra-embryonic, and germline lineages, giving rise to gonadal PGC-like cells that did not acquire full germline competence. We further demonstrate that the T7 system generates iPSCs from quail, duck, peacock, zebra finch, and pigeon, and that duck iPSCs can form interspecies chimeras with donor cells detected in the host gonads. These findings establish a generalizable platform for avian iPSC generation with applications in developmental biology and germline preservation of endangered species. Full article

Acute gastroenteritis is a common condition with a wide and often indistinguishable etiology, requiring laboratory support for an accurate diagnosis. Classical diagnostic methods, including stool culture and antigen-based tests, are limited by restricted pathogen coverage and variable sensitivity. In the present study, 548 stool samples from patients with suspected gastroenteritis were tested using the QIAstat-Dx Gastrointestinal Panel 2 and compared with stool culture and rotavirus/adenovirus antigen tests. The molecular panel showed a positivity rate of 50.4%, consistently higher than stool culture (12.6%) and antigen assays (12.3% for rotavirus and 4.4% for adenovirus). The most frequently detected pathogens included enteropathogenic Escherichia coli (15.3%), Campylobacter spp. (12.0%), and enteroaggregative E. coli (10.2%). Agreement between methods was good for bacterial pathogens but low for viral targets. Discordant viral results were often associated with low antigen cut-off index values and multiple pathogen detections by the molecular panel, suggesting potential limitations of antigen-based assays. Overall, the QIAstat-Dx Gastrointestinal Panel 2 improves pathogen detection and provides rapid, comprehensive diagnostic information, while a combined approach with conventional methods may represent the most appropriate strategy for optimizing patient management. Full article

Amaranthin is a major red-violet betacyanin of Amaranthaceae and an increasingly relevant natural pigment for food, cosmetic, nutraceutical, and biotechnological applications. This review integrates knowledge from over 100 studies, addressing amaranthin as a chemically defined betalain, distinguishing it from other scientific uses of the term, and evaluates its natural sources, analytical methods, extraction strategies, in vitro production systems, biosynthetic regulation, and biological activity. Cultivated Amaranthus species are among the richest plant sources, with total betacyanins of 46.1–199 mg/100 g fresh weight and amaranthin comprising, on average, 80.9% of the pigment fraction. Reliable identification and quantification rely on high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD), liquid chromatography-tandem mass spectrometry (LC-MS/MS), and ultraviolet–visible (UV–Vis) spectrophotometry. Microwave- and ultrasound-assisted extraction can improve pigment recovery under optimized conditions, although its stability depends strongly on pH, temperature, solvent, time and storage parameters. While plant in vitro cultures, including callus, suspension, and shoot systems, have clarified biosynthetic regulation and offer controlled production platforms, engineered yeast systems have recently expanded production options, with Yarrowia lipolytica reaching 2.97 ± 0.029 g L⁻¹ amaranthin in fed-batch fermentation. Amaranthin-rich extracts and amaranthin-type pigments show antioxidantand anti-inflammatory potential, while antimicrobial and antiviral activities have mainly been reported for mixed betacyanin fractions; direct mechanistic, bioavailability, and in vivo evidence for purified amaranthin remains limited. Standardized analytical protocols, further investigation of stable high-yield sources, physicochemical stability assessment, and structure–activity studies are identified as priorities for advancing future application-oriented research on this multipotential pigment. Full article

The (3aS, 6aR)-lactone serves as the key chiral intermediate for the synthesis of d-biotin. A promising approach involves the asymmetric hydrolysis of meso-dimethyl ester catalyzed by an esterase to yield the (4S, 5R)-monomethyl ester, which is subsequently reduced and cyclized to afford (3aS, 6aR)-lactone. This study first optimized the fermentation medium and culture conditions for the recombinant E. coli pET21a-EstSIT01 harboring the Microbacterium esterase gene, which exhibits high selectivity for the asymmetric synthesis of (4S, 5R)-monomethyl ester. Under optimal conditions (fermentation medium: glycerol 25 g/L, yeast extract 15 g/L, NaCl 10 g/L, MgSO₄•7H₂O 5 g/L; induction was initiated 2 h post-inoculation at 30 °C and pH 7.2), the enzyme activity increased 5.1-fold compared to the initial level, reaching 1072.7 U/L. Secondly, the reaction conditions for the whole-cell synthesis of (4S, 5R)-monomethyl ester catalyzed by EstSIT01 were optimized. The results indicated that organic solvents adversely affected enzyme stability, while high buffer salt concentration negatively impacted enzyme activity at elevated substrate concentrations. The optimal reaction strategy involved maintaining the pH of the aqueous reaction system at 7.5 by the controlled addition of aqueous ammonia to neutralize the (4S, 5R)-monomethyl ester produced during the reaction. Using 17.5 g/L cells and 200 mM substrate meso-dimethyl ester in deionized water, with the reaction pH mentioned at 7.5, complete conversion (100%) was achieved within 4 h at 30 °C. The space–time yield reached 441.6 g/L/d, exceeding the typical requirement for industrial biotransformation (>100 g/L/d), with 99.1% enantiomeric excess (ee) of (4S, 5R)-monomethyl ester. Finally, (4S, 5R)-monomethyl ester was reduced using sodium borohydride to synthesize (3aS, 6aR)-lactone with an ee value of 98.7%. The overall yield from meso-dimethyl ester to (3aS, 6aR)-lactone was 86.2%. These results demonstrate that this integrated chemo-enzymatic approach constitutes a greener method with promising potential for industrial application. Full article

Listeria monocytogenes is a persistent foodborne pathogen capable of forming biofilms and surviving in food-processing environments. This study investigated the impact of high-pressure processing (HPP) at 200 and 400 MPa/5 min on biofilm viability, biomass, and expression of nine virulence-associated genes in L. monocytogenes strains (n = 6) belonging to the serogroups IIa (LM8, LM40, LM41) and IVb (LM14, LM47, LM48). The pressure levels applied were selected to represent sublethal HPP conditions (below 600 MPa) that allowed the survival of the strains and thus enabled the investigation of adaptive responses in cells that escape complete inactivation. Biofilms were cultivated on stainless-steel 304, polyethylene terephthalate, and polypropylene coupons under static conditions at 25 °C for 72 h and 168 h. Biofilm viability [log₁₀(CFU/cm²)] was assessed by plate count method and biomass quantified via the biofilm production index (BPI). The cultures were subjected to HPP treatment and their ability to form biofilms was re-evaluated. HPP significantly (p < 0.05) reduced biofilm viability and biomass on all types of surfaces tested. Gene expression analysis revealed a pressure-dependent (p < 0.05) modulation of flaA and sigB, while other virulence genes (agrA, agrC, actA, prfA, hly, inlB, and degU) were generally downregulated (gene expression ratio values below 1). Serogroup IVb strains exhibited enhanced stress responses and lower biofilm survival on polyethylene terephthalate and polypropylene surfaces. These findings demonstrate that HPP modulates both phenotypic and genotypic traits linked to L. monocytogenes persistence, emphasizing the need to optimize pressure parameters and surface materials to prevent biofilm formation in HPP-treated food systems. Full article