Search Results (996)

Lactic Acid Bacteria (LAB)-derived antimicrobial compounds are recognized as a promising source of novel antimicrobial agents, particularly for the treatment of Methicillin-Resistant Staphylococcus aureus (MRSA), where the mode of action and associated cellular effects remain largely unexplored. This study aims to evaluate antibacterial activity of Limosilactobacillus fermentum YTPP05 isolated from pickled radish against MRSA. Upon the initial antibacterial evaluations, it was found that strain YTPP05 inhibited the growth of MRSA isolates. Multiplex PCR identified multiple resistance genes in our MRSA strains, including mecA, blaZ, and aacA genes, aligning with antibacterial susceptibility profiles determined by the disc diffusion assay. An agar overlay assay showed that YTPP05 possessed antibacterial potential, with the largest inhibition zone diameters of 40.83 ± 8.43 mm, while the inhibition zones of the Cell Free Supernatant (CFS) of YTPP05 by an agar well diffusion were 27.16 ± 2.93 mm against the MRSA isolates. The minimum inhibitory concentration and minimum bactericidal concentration of YTPP05-derived CFS were 125 mg/mL. Scanning Electron Microscopy (SEM) demonstrated YTPP05 extracts caused cell membrane disruption, bubble-like protrusion, and cell lysis. Collectively, this study highlights the anti-MRSA potential of YTPP05 as an alternative antimicrobial agent for combating MRSA infections. Full article

Bacterial β-barrel pore-forming toxins, including Staphylococcus aureus α-toxin (Hla) and Bacillus cereus toxins hemolysin II (HlyII) and cytolytic toxin K2 (CytK-2), are secreted by bacterial cells as water-soluble monomers. These monomers assemble within lipid bilayers to form cylindrical pores, leading to lysis of target eukaryotic cells. We created mutant forms of these toxins that, based on the results of X-ray structural analysis of Hla and the prediction of the 3D structure of HlyII and CytK2, can form intramolecular disulfide bonds in monomers. The substitutions were made in the region responsible for toxin insertion into the target membrane. The mutant forms reversibly altered their hemolytic activity depending on the presence of reducing reagents and were non-toxic when injected into experimental animals. The immune response to injection of the mutant forms of Hla and CytK-2 toxins resulted in higher antibody titers against the wild-type toxins and a higher level of immunological memory than with injection of the HlyII mutant. The mutant form of CytK-2 demonstrates the properties of a prototype vaccine, as immunization with this protein protects animals against the effects of the wild-type toxin. Full article

The high prevalence of biofilm-associated multidrug-resistant (MDR) Escherichia coli infections in older adults calls for novel control strategies. This study compared fecal E. coli carriage, antimicrobial resistance, and biofilm formation among community-dwelling older adults with different self-reported immune statuses (lower vs. normal), and evaluated the antibiofilm activity of five Lactobacillus cell-free supernatants (CFSs). Fecal samples from 20 older adults were analyzed. E. coli was enumerated, and isolates were characterized for antimicrobial susceptibility and biofilm formation. Five Lactobacillus strains were screened for antibiofilm activity using crystal violet assay, with further evaluation of extracellular polymeric substance (EPS) production and biofilm morphology. After removing the redundant isolates, 70 isolates were reported, with significantly higher counts in the lower-immunity group (7.89 vs. 6.04 log MPN/g). The lower-immunity group had significantly higher antimicrobial resistance (97.3% vs. 60.6%), and higher MDR prevalence (91.7% vs. 24.2%). Biofilm formation was observed in 62.9% of isolates, with significantly higher prevalence among MDR isolates and in the lower-immunity group. L. paracasei L475 CFS showed the strongest antibiofilm activity against a representative MDR isolate (L5-1), with inhibition and eradication rates of 82.9% and 75.0%, respectively. Mechanistically, L475 CFS reduced extracellular polymeric substance components, with a 92.3% reduction in proteins and 41.3% in polysaccharides. Microscopy confirmed disrupted biofilm architecture, membrane damage, and cell lysis. In conclusion, these preliminary findings indicate a potential association between self-reported immune function and E. coli resistance/biofilm formation in older adults. L. paracasei L475 CFS demonstrates promising in vitro antibiofilm activity against an MDR E. coli isolate from this population, supporting its potential as a postbiotic candidate. Full article

Circulating tumor cells (CTCs) are valuable liquid-biopsy biomarkers, yet their extreme rarity makes high-purity, high-throughput enrichment challenging. In spiral inertial microfluidics, high cell loading induces long-range hydrodynamic interactions that broaden the focused blood-cell stream; consequently, a subpopulation completes the ~0.5 and ~1.0 Dean-cycle migrations with a phase delay, compressing the CTC–blood cell gap and degrading purity. Here we propose a Dean-cycle phase-regulated double-spiral design informed by this phenomenon. This design aims to mitigate the stream-broadening effect by boosting the Dean number during the first half-cycle to promote synchronized blood-cell migration and shifting the CTC equilibrium position near one full cycle to further widen the CTC–blood cell separation. We implement this strategy in a second-generation double-spiral microfluidic chip (SDMC) and scale it to a four-channel parallel array (ASDMC). Under optimized conditions, ASDMC processes diluted whole blood (hematocrit = 4%) without the need for red blood cell (RBC) lysis or antibody labeling, achieving a sample throughput of 1200 μL·min⁻¹. Specifically, it exhibits a mean recovery rate of 98.8% across three spiked tumor cell lines (MCF-7, PC-9, and Mahlavu) and a mean white blood cell (WBC) depletion efficiency of 93.3%. In a pilot clinical testing of 20 patients (NSCLC and HCC), enriched fractions enabled immunofluorescence identification of CK⁺CD45⁻DAPI⁺ CTCs, with an exploratory trend of increasing CTC counts with advanced disease stage (4–34 cells·mL⁻¹). These results describe a scalable, label-free platform, and the observed purification performance aligns with our proposed mechanism: Dean-cycle phase regulation to mitigate blood-cell migration lag. Our findings support further technical validation and clinical assessment in larger cohorts. Full article

Shear stress is a significant consideration in 3D bioprinting systems, with implications for cell viability and behaviour. This study hypothesised that relevant levels of shear stress would be generated during the process of 3D bioprinting human nasoseptal chondrocytes in a nanocellulose alginate bioink, with implications for cell viability and chondrogenic gene expression. Through a combined approach of in silico modelling and in vitro testing, we assessed chondrocyte viability and gene expression immediately within the first 72 h post-printing. Cell viability was determined using live–dead, alamarBlue and lactate dehydrogenase assays immediately and 24 h post-printing compared to cell-only and unprinted cell–biomaterial controls. Gene expression analysis of Type 2 collagen, SOX9, aggrecan and alkaline phosphatase gene expression was performed 4 h and 72 h post-printing. Computational fluid dynamics predicted a shear stress of 292 Pa and maximum fluid velocity of 19 mm/s during the bioprinting process. No statistically significant cell death or cell lysis was detected between groups immediately post-printing; however, statistically significant chondrocyte cell death was observed at 24 h in the printed group (p = 0.047). Moreover, the bioprinting process evoked a transient initial rise in both chondrogenic (SOX9, aggrecan) and osteogenic gene expression (ALP) with a marked suppression in type 2 collagen expression at 72 h (0.05, p = 0.0005), indicating biological effects evoked by shear stress during printing. This study highlights the importance of optimising the bioprinting process to facilitate low shear stress conditions for durable cartilage tissue engineering. Full article

The use of cytostatic drugs for cancer treatment is currently the main weapon in the fight against cancer; however, prolonged exposure of healthcare personnel can cause adverse toxic effects. Objective: To determine the genotoxicity caused by exposure to cytostatic drugs, using the comet assay, in workers in the oncology department of a tertiary hospital in northern Peru. Methodology: Descriptive, quantitative, correlational, and cross-sectional study. The population consisted of two groups of workers: exposed (n = 40) and unexposed (n = 40). The alkaline lysis comet DNA technique was used on peripheral blood cells; tailing moment and tailing percentage indicators were evaluated. Results: Using nonparametric tests, the percentage and tail moment showed no significant differences, with p values of 0.8928 and 0.4675, respectively. The distribution observed in the group exposed to cytostatic drugs (pharmacists and pharmacy technicians) compared to the control group showed a normal distribution, with a tail moment of 8.29 vs. 3.03 and a percentage of tail of 37.12 vs. 23.24, respectively. Multivariate analysis showed that the tail moment variable was 11.56% greater in the group of pharmacists and pharmacy technicians (p = 0.0119) compared to the other participants. Conclusions: Although no significant difference was found, a trend toward a higher percentage and tail moment was observed in the group exposed to cytostatic drugs. Furthermore, the group of pharmacists and pharmacy technicians, compared to the other professions, showed significantly greater damage. Full article

Exopolysaccharides secreted by Geobacter play a pivotal role in mediating extracellular electron transfer (EET), biofilm formation, and environmental adaptability. However, existing methods for extracting and purifying Geobacter exopolysaccharides often suffer from low yield, structural damage, or contamination by intracellular components, limiting in-depth research on the structure and function of exopolysaccharides. This paper aimed to optimize the extraction and purification protocols for Geobacter exopolysaccharides. Three crude extraction methods (EDTA, high-speed centrifugation, and heating) for exopolysaccharides were evaluated, and the EDTA method was selected as the optimal crude extraction strategy, balancing exopolysaccharides yield (22.3 μg/mL) and cell viability (90.1%), outperforming high-speed centrifugation (lower yield) and heating (severe cell lysis). Purification was optimized using a two-step process: for deproteinization, the Sevag method was optimized to four cycles, removing 75% of proteins with minimal exopolysaccharides loss. Ethanol precipitation was optimized to 75–90% concentration and 24 h incubation, yielding 19.6–20.9 μg/mL of purified exopolysaccharides while eliminating soluble impurities. This optimized protocol ensures high-quality exopolysaccharides isolation with minimal cell lysis and reduced risk of structural disruption, providing a reliable foundation for investigating the roles of Geobacter exopolysaccharides in EET and environmental applications. Full article

Parainfluenza virus 5 (PIV5) can establish persistent infections in host cells despite encountering innate immune defenses, including the complement (C′) system. The host determinants that enable persistently infected cells (PI) to evade C’-mediated clearance remain largely undefined. Here, we identify the mitochondrial antiviral signaling (MAVS) protein, a central adaptor in double-stranded RNA-triggered antiviral and pro-survival signaling pathways, as a critical mediator of both PIV5 persistence and acquired resistance to C’ lysis. Wild-type (WT) PIV5-infected A549 cells were initially sensitive to C’-directed killing, but these cells rapidly establish a PI in culture with ~25% of the cell population becoming resistant to C’ lysis by day 2 and ~75% by day 4. In contrast, PIV5-infected A549 MAVS-deficient (MAVS KO) cells exhibited elevated viral gene expression, increased deposition of C3 and the membrane attack complex, and were more susceptible than WT cells to C′ killing. PIV5-infected MAVS KO cells showed rapid cytopathic effects and never established a stable PI. While pharmacological suppression of viral gene expression with ribavirin (RBV) restored the survival of PIV5-infected MAVS KO cells into a long-term PI-like state, these RBV-induced PI cells remained sensitive to C’ lysis. Collectively, these findings demonstrate a role of MAVS in modulating a PIV5 infection in culture, to facilitate both the conversion of a PIV5 acute infection to a PI and development of resistance to C’ killing. Full article

The aim of this study was to investigate which physicochemical and structural properties of cationic peptides P1–P6 may determine their selective anticancer activity against melanoma cells and their interactions with tumor cell membranes. An integrated approach was applied, including characterization in solution (osmotic pressure, NaCl stability, surface tension); cytotoxicity evaluation against Me45, B16F10, and HaCaT cells; analysis of interactions with phosphatidylglycerol (POPG) model membranes using isothermal titration calorimetry and steady-state fluorescence spectroscopy; membrane permeability assays; and F-actin staining. Anticancer activity depended on positively charged residues, hydrophobic amino acids, and sequence arrangement. Tryptophan-rich peptides P2 and P5 exhibited strong membrane interactions and high efficacy after 72 h. Highly hydrophobic P4, containing long C₁₂ chains with a relatively low net charge, caused nonselective lysis. P3 showed reduced activity due to insufficient amphipathicity, whereas P6, with excessive WWW and KKKK motifs, exhibited weak or nonselective effects. Thermodynamic and fluorescence analyses indicated that P2 and P5 initially bind POPG membranes via entropy-driven electrostatic interactions, followed by hydrophobic insertion of tryptophan residues, evidenced by increased fluorescence intensity and a blue shift of the emission maximum. P2, P4, and P5 induced actin cytoskeleton reorganization and increased membrane permeability, emphasizing the role of balanced amphipathicity and charge–hydrophobicity in designing selective anticancer peptides. Full article

Stem cells, also known as progenitor cells, can differentiate into specialized cells for specific tissues. Genetic mutations and epigenetic changes may cause normal stem cells to become cancer-initiating cells. Research indicates that cells acquiring a mutation for myeloproliferative neoplasm (MPN) are likely to be long-term hematopoietic stem cells (LT-HSCs) at the top of the hematopoietic hierarchy. Natural killer (NK) cells play a crucial role in combating cancer by targeting and eliminating cancer stem cells (CSCs) while promoting their maturation. NK cells do this through direct lysis of CSCs or by releasing cytokines like interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α), which inhibit tumor growth and metastasis by driving differentiation of CSCs. Interleukin-2 (IL-2) enhances the activity of CD4+ and CD8+ T cells and boosts NK cell cytotoxicity. This study highlights a case of MPN with a more clinically aggressive Type 1 calreticulin (CALR) mutation, where a combination of low-dose IL-2 immunotherapy and targeted therapy with oral tretinoin (all-trans retinoic acid, ATRA, a vitamin A derivative) improved immune cells, particularly NK-cell-mediated destruction of malignant cells, reduced CALR mutation levels to undetectable, and alleviated disease symptoms. The aim is to offer a new, low-toxicity personalized treatment strategy that eradicates cancer-initiating stem cells, reduces side effects, and provides an option for patients with limited conventional therapy alternatives. Full article

Immobilized microorganism technology offers a promising approach for remediating heavy metal-contaminated soils. This study developed a novel bio-mineral composite (B-AM) by coupling acid-modified maifanite (AM) with Bacillus mucilaginosus to enhance lead (Pb) immobilization. Comparative experiments demonstrated that B-AM outperformed conventional amendments, including oyster shell, pristine maifanite, AM and B. mucilaginosus in Pb immobilization. The B-AM treatment optimized soil pH, improved soil fertility with increases in available potassium (1.06-fold) and available phosphorus (1.28-fold). Additionally, B-AM transformed Pb into more stable fractions, reducing labile Pb fractions by 52.52% while increasing the residual fraction by 88.36%. These improvements resulted in an 83.24% reduction in Pb accumulation and a 63.95% increase in the fresh root weight of radish. Mechanistic insights revealed that the enhanced remediation performance stems from both the individual contributions of AM (adsorption capacity) and B. mucilaginosus (biosorption and biomineralization) and their synergistic interaction. Specifically, AM acts as a carrier and pH buffer, promoting microbial proliferation and reducing Pb remobilization from cell lysis. The resulting sustained microbial activity further leads to the formation of stable Pb minerals. Collectively, our results establish a theoretical and practical basis for using B-AM to remediate Pb-contaminated soils. Full article

Background/Objectives: Acute myeloid leukemia (AML) is characterized by impaired anti-leukemic immune responses, and the ex vivo or in vivo generation of dendritic cells (DCs), including leukemic dendritic cells (DC_leu), represents a promising strategy to stimulate immune cells and improve anti-leukemic activity. Methods: This study examined the generation, phenotype and functional relevance of DCs and DC_leu produced ex vivo from blast-containing PBMNCs and whole blood (WB) in AML. Using both standard DC/DC_leu-generating protocols and available Kits. Results: We show that DC/DC_leu can be reliably generated with both methods. Generated DC/DC_leu effectively activated T cells during mixed lymphocyte cultures (MLCs), resulting in enhanced anti-leukemic cytotoxicity. Improved blast lysis correlated with specific immunological features, including higher frequencies of generated DC_leu and mature DC subsets, as well as a certain cytokine pattern after DC/DC_leu cultures or MLC. In addition, the frequencies of proliferating T cells after MLC strongly correlated with the degree of achieved blast lysis, underscoring the importance of efficient DC/DC_leu-mediated T cell stimulation. Both the frequencies of generated DC/DC_leu and the resulting blast lytic activity were linked to overall survival (OS) in AML patients. Individuals who failed to demonstrate improved blast lysis exhibited significantly reduced OS, suggesting inadequate immune responsiveness of patients in vivo. Conclusions: These findings identify phenotypic and functional immune parameters as predictors of clinical outcome and highlight the prognostic relevance of ex vivo immune profiling. This approach may help to optimize and personalize future immunotherapeutic strategies in AML. Full article

Growing interest in natural therapies has increased the demand for essential oils; however, the complex interactions within their mixtures that dictate their final efficacy remain poorly understood. This study aimed to optimize a blend of ginger, cinnamon, tea tree, and geranium essential oils to develop an active ingredient, with synergistic multifunctional bioactivities, that was relevant to cutaneous healing. Initially, the composition and cytotoxicity for individual oils were determined; subsequently, a D-optimal mixture design was employed to evaluate three biological responses related to skin recovery: ultraviolet B radiation absorption, red blood cell lysis inhibition, and catalase enzyme activity. GC-FID analysis revealed the following major components (% w/w): cinnamon (cinnamaldehyde, 77.56%), ginger (α-zingiberene, 33.77%), geranium (citronellol, 33.6%), and tea tree (terpinen-4-ol, 38.38%). Dose–response data from essential oils tested against Detroit ATCC 551 skin fibroblasts revealed a clear cytotoxic hierarchy (IC₅₀ µg/mL): cinnamon (21.03) > ginger (25.3) > tea tree (41.67) > geranium (92.51). Cinnamaldehyde content was the primary contributor to photoprotective capacity, with a maximum sun protection factor (SPF) of 4.5. Inhibition against erythrocyte membrane lysis was not attributable to a single component; maximum protection (98.4%) was achieved through synergy between oxygenated monoterpenoids (geranium and tea tree), sesquiterpenes (ginger), and aromatic aldehydes (cinnamon). Highest catalase activity (160.86 kU/g Hb) was reached in mixtures with high cinnamaldehyde and eugenol contents, whereas an antagonistic effect was observed between tea tree and geranium oils. Finally, an optimal formulation (desirability = 0.927) was identified (% w/w): 31.7% ginger, 39.1% cinnamon, 14.5% tea tree, and 14.7% geranium. Experimental validation confirmed no significant difference compared with developed predictive models. This optimized mixture constitutes a bioactive natural component with potential for use in products aimed at promoting skin health, warranting further investigation into direct models of skin healing. Full article

Natural Killer (NK) cell-based immunotherapy relies on CD16-mediated Antibody-Dependent Cellular Cytotoxicity (ADCC), yet the ovarian tumor microenvironment (TME) severely compromises this function via Transforming Growth Factor-beta (TGF-β). This study investigated the molecular mechanisms driving this suppression and evaluated a bi-specific Chimeric Antigen Receptor (CAR) strategy to overcome this hurdle. Primary PBNK cells exposed to TGF-β showed sustained canonical SMAD2 phosphorylation, accompanied by a marked reduction in activating receptors such as CD16 and NKG2D and an increase in exhaustion markers such as PD-1. Functionally, these phenotypic alterations led to failed infiltration and cytotoxicity in vitro and within ovarian cancer-derived spheroids. To overcome this limitation, we engineered NK-92 cells with a bi-specific CAR-targeting Folate Receptor Alpha (FRα) and CD16. While TGF-β typically impairs NK cell function, our armed CAR-NK cells successfully infiltrated tumoroids and synergized with Trastuzumab to induce potent ADCC-mediated lysis. Our findings define the TGF-β/SMAD2 axis as a central driver of NK cell dysfunction in ovarian cancer and demonstrate that bi-specific CAR-NK platforms offer a robust therapeutic solution to bypass TME-induced suppression and restore antibody-mediated tumor suppression. Full article

Streptococcus suis is one of the most important zoonotic pathogens threatening the lives of pigs and humans. Increasingly severe antimicrobial resistance in S. suis is becoming a global issue. Therefore, there is an urgent need to discover novel antibacterial alternatives for the treatment of S. suis infections. The current study investigated aurisin A, an aristolane dimer sesquiterpene isolated from the luminescent mushroom Neonothopanus nambi Speg. (Marasmiaceae), against S. suis. The minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of aurisin A against S. suis strains were in the range of 1.94–62.5 μg/mL. Scanning electron microscopy showed that aurisin A induced alterations in the cellular structure of S. suis, including a significantly wrinkled surface, intracellular content leakage, and cell lysis. The crystal violet staining assay illustrated that aurisin A significantly inhibited biofilm formation of S. suis strains at sub-MICs and exhibited strong degrading activity against the preformed biofilms. Aurisin A significantly inhibited the adhesion, cell death, and cytotoxic activities of S. suis in lung epithelial cells in a concentration-dependent manner. Additionally, aurisin A significantly reduced the hemolytic effect of S. suis on defibrillated sheep blood, indicating protective activity of aurisin A against this bacteria. Taken together, these findings highlight aurisin A as a promising therapeutic candidate for the treatment of S. suis infections, with key roles in inhibiting biofilm formation and hemolytic activity, as well as providing protective effects to epithelial cells, including anti-adhesion, anti-cytotoxicity, and anti-cell death activities. Full article