Search Results (230)

The effects of nisin on growth inhibition and biofilm formation were studied in two Listeria monocytogenes strains, LM_ATCC 19115 and LM_18, at concentrations ranging from 14 to 450 µg/mL. The maximum rate of OD₆₀₀ increase (μ_max) showed no significant concentration-dependent change in LM_ATCC 19115, whereas LM_18 exhibited a downward trend. Maximum OD₆₀₀ dropped progressively and significantly at 225 and 450 µg/mL in both strains. Although concentrations of 14–56 µg/mL supported gradual growth that paralleled the control, the highest nisin concentrations significantly prolonged the lag phase of both strains and eventually decreased biomass by 64% and 51% for LM_ATCC 19115 and LM_18, respectively. Consequently, nisin reduced biofilm formation, with no biofilm observed for LM_ATCC 19115 at 450 µg/mL. However, both strains retained biofilm-forming capacity at 14–113 µg/mL concentrations. In LM_ATCC 19115, biofilm formation decreased independently of growth, along with significantly increased expression of the motility gene flaA and quorum sensing regulator agrA. In contrast, for LM_18, biofilm reduction corresponded to growth inhibition, with significant downregulation of the virulence gene hly. The observed strain-specific patterns of growth and biofilm formation warrant further investigation with a broader range of strains to better define and address the limitations of nisin application. Full article

Fresh pork remains susceptible to psychrotrophic spoilage during superchilled storage. Although oregano essential oil (OEO), nisin, and active absorbent pads have each been studied, their effects on spoilage-community proliferation and concurrent quality loss remain poorly resolved. Here, we coupled longitudinal 16S rRNA gene profiling with conventional microbiological and quality measurements to evaluate a poly(vinyl alcohol)/soy protein isolate pad containing OEO-loaded soluble soybean polysaccharide-nisin nanoparticles (PS-NPs). Pork was stored at −1 °C for 24 days without a pad (CK), with a nanoparticle-free pad (PS), or with PS-NPs. Bacterial communities in CK and PS-NPs were profiled alongside total viable count, TVB-N, TBARS, protein carbonyls, color, water-holding capacity, and sensory quality. Compared with CK, PS-NPs slowed the increase in viable counts and delayed physicochemical and sensory deterioration. On day 24, Pseudomonas relative abundance was 39.48% with PS-NPs and 51.02% in CK. TBARS and protein carbonyl contents were 36.96% and 19.44% lower than CK, respectively, while cooking loss was 28.49% versus 32.18%. Among the evaluated taxon-quality pairs, Pseudomonas psychrophila showed the strongest positive association with protein carbonyl content. Unlike earlier performance-focused studies, this work links packaging-associated community shifts with concurrent chemical, physical, and sensory changes under superchilling. The findings support PS-NPs as a preservation strategy. Full article

Background/objectives: Foodborne diseases remain a significant global public health concern, requiring innovative and effective antimicrobial strategies to control food pathogens. Encapsulation of natural antimicrobials have attracted increasing interest. In this study, liposomes encapsulating pink pepper essential oil (PPEO), nisin, or their combination were developed, aiming to potentiate antimicrobial performance against foodborne pathogens. Methods: Phosphatidylcholine liposomes were prepared by the thin-film method and characterized by DLS and FTIR. The antimicrobial activity of nisin, PPEO, and liposomes was investigated by the agar diffusion method against foodborne pathogens like Staphylococcus aureus, Listeria monocytogenes, and Salmonella Typhimurium. Results: The liposomes exhibited nanometric size ranging from 91 to 107 nm, low polydispersity, and zeta potential between −3.73 and −7.39 mV, indicating well-defined vesicles with negative surface charges. Encapsulation enhanced antimicrobial efficacy, with nisin–PPEO liposomes stored for 21 days under refrigeration showing a sustained inhibition of L. monocytogenes, outperforming liposomes containing nisin alone. The combined antimicrobials also inhibited Gram-positive bacteria in milk agar, used as a simulated food system. Additionally, the antioxidant activity of PPEO was preserved upon encapsulation, especially under refrigeration, reinforcing the protective role of the liposomes. Conclusions: The co-encapsulation approach strengthened the stability and bioactivity of natural antimicrobials, highlighting liposomal delivery as a promising strategy to control foodborne bacteria. Full article

Biofilm-mediated antimicrobial resistance remains a significant challenge for healthcare and patient safety. Currently, there are gaps in standardised methods for assessing antimicrobials against biofilm formations such as (1) assessment of initial bacterial attachment inhibition, as well as (2) assessment of antimicrobial compounds against both the external biofilm mass and biofilm-embedded metabolically active bacteria. The aim of this study is to address these gaps by combining several anti-biofilm techniques. In the procedure96-well anti-biofilm assessments were performed using plate well and lid peg growth surfaces so as to determine the effects of bioactive compounds (silver nitrate (AgNO₃), nisin, chitosan and zinc oxide nanopowder (ZnO)) on biofilm growth inhibition, formed biofilm reduction and bacterial attachment inhibition. These studies focused on the initial attachment stage against in vitro biofilms of P. aeruginosa and S. aureus. Effects were measured against biofilm mass using Crystal Violet (CV) staining, while embedded bacteria metabolic activity was measured using Resazurin. AgNO₃ exhibited significant inhibition and reduction against P. aeruginosa at all stages of biofilm development (p < 0.0001). AgNO₃ showed significant results against S. aureus during biofilm development and against the embedded, metabolically active population of established biofilms (p < 0.0001). Nisin showed significant inhibition against S. aureus biofilm populations (p < 0.0001). Chitosan showed significant increases in S. aureus biofilm formations following exposure, during initial attachment (p < 0.02), during biofilm growth (p < 0.0001) and against formed biofilm populations (p < 0.0001). ZnO showed significant increases during initial attachment exposure (p < 0.0001), but also exhibited growth inhibition (p < 0.0001) and biofilm reduction (p < 0.0001). Although variance in anti-biofilm efficacy was evident depending upon treatment used, Gram-staining phenotype and test growth surfaces, this combinational method offers potential for high throughput screening and for evaluating pipeline bioactives isolated from different environments for biofilm prevention, inhibition and removal. Additionally, this approach will help elucidate the relationship between bacteria of interest and biofilm mitigation. Full article

Peptide therapeutics have emerged as a versatile class of biomolecules bridging the gap between small-molecule drugs and large biologics. Advantages of such molecules include high target specificity, potent bioactivity and reduced off-target toxicity. Despite these, broader clinical translation remains constrained by inherent limitations like poor metabolic stability, rapid renal clearance, limited membrane permeability and scalable synthesis. This review aims to systematically integrate advances in peptide science across natural discovery, synthetic methodologies, structural engineering, and translational delivery systems, while identifying critical research gaps hindering clinical adoption. We highlight diverse natural sources of bioactive peptides, including plant- (lunasin), animal- (Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP)), microbial- (nisin and cyclosporine), marine- (dolastatins) and venom-derived (chlorotoxin and ω-conotoxin MVIIA (ziconotide)) agents. Advances in solid-phase peptide synthesis (SPPS), green chemistry, and catalytic strategies are discussed alongside emerging in silico approaches, including artificial intelligence-driven sequence design and molecular modeling. Structural modifications such as cyclization, hydrocarbon stapling, PEGylation, and lipidation are critically evaluated for their role in enhancing pharmacokinetic and pharmacodynamic properties. Furthermore, nanoformulation strategies, including self-assembling peptides and cell-penetrating systems, are examined for their potential to overcome biological barriers. Importantly, this review identifies key unresolved challenges, including the lack of predictive models for peptide delivery systems, safety concerns associated with long-term modifications, and limited in vivo validation of naturally derived peptides. Addressing these gaps through integrated computational and experimental approaches will be essential for advancing next-generation peptide therapeutics. Collectively, this work provides a comprehensive framework for the rational design and translation of peptide-based precision medicines. Full article

Bipolar cancellation (BPC) is an efficiency-limiting phenomenon in bipolar nanosecond pulsed electric field (nsPEF) exposures, in which the second, opposite-polarity phase reduces or partially reverses the electroporation induced by the first phase. Nisin, a cationic antibiotic peptide, has been reported to interact with lipid membranes in bacterial systems and artificial bilayer models, where it may contribute to membrane destabilization and increased permeability during pulsed electric field exposure. This study investigated whether nisin may enhance the efficacy of bleomycin electrochemotherapy (ECT) in the presence of bipolar nanosecond pulses, which are typically associated with pronounced BPC effects. Pulsed electric field (PEF) parameters and drug concentrations were selected based on preliminary viability and Yo-Pro-1 uptake experiments in CLS-354 human squamous cell carcinoma cells. To evaluate the effect of nisin, cell viability and membrane permeabilization were assessed following exposure to 300 ns pulses across a range of bipolar PEF protocols, with or without nisin, while identical unipolar pulses were used for comparison. Nisin (50 µg/mL) increased membrane permeabilization across the tested range of field amplitudes (9–15 kV/cm) and burst repetition frequencies (0.1–1.66 MHz). The presence of nisin was also associated with increased efficacy of bleomycin-based ECT under both unipolar and symmetrical bipolar PEF conditions. Under the optimized parameters tested (13 kV/cm; 150 pulses of 300 ns at 1.66 MHz), bipolar nsPEFs in combination with nisin reached levels of efficacy comparable to those observed with unipolar waveforms, suggesting a potential attenuation of bipolar cancellation effects. Full article

The growing problem of antibiotic resistance poses one of the greatest threats to modern medicine, making the search for new, alternative strategies to treat bacterial infections a matter of priority. The aim of the study was to evaluate the antimicrobial activity of selected postbiotic substances (PS) and nisin against methicillin-susceptible (MS) and methicillin-resistant (MR) strains of coagulase-negative staphylococci (NAS) and mammaliicocci. The study was conducted on 24 strains of coagulase-negative staphylococci and mammaliicocci isolated from milk collected from Holstein-Friesian (HF) cows with subclinical mastitis. In vitro, PS/EMo (100–400 AU/mL) and PS/Eas (100–200 AU/mL) were the most effective, inhibiting the growth of all MS and MR strains of NAS and Mammaliicoccus spp. (100.0%). A high percentage of strains were also sensitive to postbiotic substances produced by Lactococcus lactis subsp. lactis PS/MK2/8 (400–1600 AU/mL), PS/MK1/3 (100–400 AU/mL), and nisin (100–25,600 AU/mL), both in MR strains (94.1%, 82.4%, 88.2%, respectively) and in MS strains (100.0%, 85.7% and 100%, respectively). PS/Esach (100–25,600 AU/mL) inhibited the growth of all strains, including the mecA gene-positive mammaliicocci strains (100.0%), but was slightly less effective against the MS strains (64.7%). The lowest activity was observed with postbiotic substances produced by Enterococcus faecium, PS/4231 (100–1600 AU/mL) and PS/9296 (100–6400 AU/mL), which inhibited the growth of 3 out of 17 MR strains (17.65%). Among the Mammaliicoccus strains with the mecA gene, postbiotic substances derived from strains PS/4231 and PS/9296 inhibited the growth of 42.9% and 28.6% of the strains, respectively. Four tested strains were sensitive to all postbiotic substances (MSC9, MSC11, MSC12 and SCH3). This study confirms that postbiotic substances and nisin inhibit the growth of staphylococci isolated from the milk of cows with subclinical mastitis, including methicillin-resistant strains. Full article

Background and Objectives: While nisin exhibits promising antitumor properties, its clinical utility is hindered by pharmacokinetic instability and rapid enzymatic degradation. This systematic review evaluates the critical role of advanced pharmaceutical formulations and targeted nanosystems in overcoming these limitations to enhance nisin’s cytotoxic and pro-apoptotic efficacy in vitro. Methods: Following PRISMA guidelines, a comprehensive search was conducted across six electronic databases (PubMed, ScienceDirect, Scopus, Web of Science, SpringerLink, and DOAJ). In vitro studies comparing free nisin against polymeric, metallic, and cyclodextrin-based nanocarriers across diverse neoplastic lineages were included. Methodological quality was assessed using the SciRAP 2.1 tool, and a within-line comparative analysis was performed for MDA-MB-231 and HT-29 models. Results: Twelve studies met the inclusion criteria. A definitive technological inflection point was identified: nisin-loaded nanosystems reduced effective concentrations by up to 2706-fold relative to the free peptide in MDA-MB-231 cells, and 71-fold in A549 lung cancer cells. Mechanistically, nanosystems facilitated membrane pore formation, mitochondrial-mediated apoptosis via Bax/Bcl-2 modulation, caspase 3/7/9 activation, and p53 reactivation. Three previously underreported mechanistic dimensions were identified: TWIST1 downregulation and FZD7 binding in hepatocellular carcinoma, and downregulation of CEA, CEAM6, MMP2F, and MMP9F in colorectal cancer lines. Conclusions: The therapeutic viability of nisin in oncology is strictly dependent on pharmaceutical engineering. Future research must prioritize in vivo pharmacokinetic validation, experimental confirmation of novel mechanistic targets, and standardized nisin purity reporting to consolidate its clinical translation. Full article

Meat products face microbial safety challenges, while growing consumer demand for “clean label” options discourages the use of synthetic preservatives. Although Nisin and cultured dextrose (CD) are known natural antimicrobials, their combined application in meat systems has not been fully assessed. Herein, we systematically evaluated the antibacterial activity of CD in combination with Nisin against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) using a uniform design. While regression modeling of the in vitro data indicated a potent synergistic interaction at lower concentrations, the optimal practical combination for meat preservation was identified as 0.02% Nisin and 0.5% CD. This combination was applied to braised chicken breast stored at 0–4 °C, with microbial counts, pH, color, and sensory quality monitored over 28 days. The results indicated that this Nisin-CD combination significantly suppressed the growth of total viable bacteria, S. aureus, and E. coli, stabilized pH, minimized color variation, and maintained sensory acceptability. Therefore, the 0.02% Nisin and 0.5% CD combination is recommended as an effective clean-label strategy to extend the shelf life of meat products by enhancing microbial safety and quality without synthetic preservatives. Full article

Due to the limitations of conventional antibiotics, antimicrobial peptides (AMPs) have emerged as promising therapeutic alternatives for the prevention and treatment of oral infections. This study systematically evaluated in vitro evidence regarding the antimicrobial and anti-biofilm activity of natural AMPs against oral pathogens. A systematic search using the PICOT strategy was conducted in PubMed, EMBASE, and Scopus, retrieving 7711 articles. After title and abstract screening, 109 studies were selected for full-text analysis, resulting in 26 articles that met the eligibility criteria. Among the AMPs evaluated, nisin (n = 15) and LL-37 (n = 5) were the most frequently investigated, while other peptides included lactoferrin, lactoferricin, melittin, lysozyme, histatin-5, cystatin C, chromogranin A, parasin-1, protamine, AmyI-1-18, and DCD-1L. Natural AMPs of human and animal origin demonstrated antimicrobial activity against bacteria associated with oral infections, particularly Streptococcus mutans and Enterococcus faecalis. These peptides were tested in different formulations, including solutions, incorporation into dental materials and polymers, and application in sonodynamic antimicrobial therapy. Overall, the findings indicate that natural AMPs represent a promising class of biomolecules for controlling oral biofilms; however, further clinical studies are required to validate their long-term efficacy and safety. Full article

Modern agriculture faces the critical need to develop sustainable, safe, and effective strategies for enhancing productivity, protecting plants and animals, and ensuring food security. Challenges posed by antibiotic resistance and the adverse environmental and consumer health impacts of chemical agents are driving the search for eco-friendly alternatives. In this context, bacteriocins—naturally occurring antimicrobial peptides synthesized by diverse bacteria—represent a promising alternative to traditional chemical compounds. This article reviews the potential and current advances in bacteriocin applications across agricultural sectors, with particular focus on their targeted antagonistic activity, structural diversity, commercial bacteriocin-based products, and their utilization in livestock farming, crop production, poultry farming, and aquaculture. Key findings demonstrate that bacteriocins, particularly nisin and pediocin PA-1, exhibit potent activity against major agricultural pathogens including Listeria monocytogenes, Staphylococcus aureus, Clostridium perfringens, and Escherichia coli, with efficacy rates reaching 90% in mastitis treatment and significantly reducing pathogen loads in poultry and aquaculture systems. Commercial products such as Nisaplin, Wipe Out, and ALTA 2431 have been successfully implemented in veterinary medicine and food production. In aquaculture, bacteriocins effectively control Lactococcus garvieae, Aeromonas spp., Vibrio spp., and Pseudomonas aeruginosa, contributing to sustainable disease management with minimal environmental impact. It can be suggested that bacteriocins may play an essential role in combating pathogens and offer viable alternatives to conventional antibiotics across primary food production systems, though optimization of production methods and regulatory frameworks remains essential for broader commercial adoption. Full article

To enhance the antibacterial properties of chitosan, this study employed papain as a biocatalyst to graft nisin onto chitosan, yielding two grafted products with grafting ratios of 8.56% (Ni1-Cs) and 14.35% (Ni2-Cs). Structure analyses confirmed the formation of amide bonds. Grafting significantly improved the solubility (92.4%), water absorption (53.4%), and film-forming properties of chitosan, with Ni1-Cs films achieving a tensile strength of 25.2 MPa. Antibacterial assays demonstrated that nisin retained favorable activity post-grafting and exhibited synergistic effects with chitosan. The minimum inhibitory concentrations (MIC) of Ni2-Cs against Escherichia coli and Staphylococcus aureus were 132.4 and 97.4 μg/mL, respectively, significantly superior to individual components. The ultra-low-temperature enzymatic method likely preserved nisin’s structural integrity. Mechanistic studies revealed that the cationic nature of chitosan and the pore-forming mechanism of nisin synergistically disrupted bacterial cell membranes. Sea bass preservation trials confirmed that Ni2-Cs coatings effectively retarded quality deterioration, inhibited microbial growth and lipid oxidation, and maintained freshness for 15 days. This study demonstrates that the ultra-low-temperature enzymatic strategy successfully prepared nisin-grafted chitosan materials with synergistic antibacterial effects, showing promising applications for food preservation. Full article

Mastitis is one of the major diseases affecting dairy cattle worldwide. Antibiotic therapy remains the most widely used treatment. However, its effectiveness has been compromised due to the selection of antibiotic-resistant and biofilm-producing pathogenic bacteria. This promotes the search for alternatives that increase the antibacterial and antibiofilm efficacy of antibiotics such ceftiofur (CFT). Nisin (N) and chitosan (CH) may possess these properties. The aim of this study was to evaluate whether N + CFT and CH + CFT combinations enhance the antibacterial activity of the antibiotic on Staphylococcus aureus associated with bovine mastitis, as well as its antibiofilm effect. Two clinical isolates of S. aureus (AMC-43 and AMC-48) and the reference strain ATCC 27543 resistant to CFT were used. Through the microdilution method in 96-well microplates, the combination of sub-inhibitory concentrations of N (320 µg/mL) and CH (400 µg/mL) with CFT (1, 2, 4, and 8 µg/mL) significantly reduced bacterial growth; however, the CH + CFT mixtures were the most efficient. The crystal violet staining method and live cell plating showed antibiofilm activity in biofilm synthesis and in the reduction in living bacterial cells located inside this preformed structure. These results highlight N and CH as potential agents for the prevention or control of bovine mastitis. Full article

Autochthonous starter and adjunct cultures have gained increasing practical research interest for use in traditional cheese-making in recent years. This study evaluated the performance of a native starter comprising Streptococcus thermophilus ST1 and two wild Lactococcus lactis strains, including the M78 nisin A-producer, during the semi-industrial production of Kefalotyri cooked hard cheese from thermized sheep milk (TM; 65 °C, 30 s) in the absence (C-cheese) or presence of the native adjunct strains Lactiplantibacillus plantarum H25 and Leuconostoc mesenteroides KFM7 + KFM9 (N-cheese). The growth of the native starter was optimal in all three cheese trials within the first 24 h of processing, but afterward, ST1 failed to exceed 8 log CFU/g in favor of total mesophilic LAB, comprising both L. lactis starter strains, and the prevalent (ca. 8.5 log CFU/g) H25 adjunct in the ripening N-cheeses. Instead, in the C-cheeses, indigenous non-Enterococcus NSLAB survivors from TM prevailed, whereas enterococci failed to increase above 6 log CFU/g in all cheeses. Although the mature (90-day-old) N-cheeses presented no statistically significant differences regarding the pH value, gross composition, and hydrophobic (HO)/hydrophilic (HI) peptide ratios from the mature C-cheeses, they had lower total LAB counts and contained less residual lactose, more acetate, and an overall less diversified volatilome (VOC) profile. The most abundant VOCs in both cheeses were acetone, butyric acid, methyl butyrate, ethyl ether, and ethanol. All mature cheeses were safe and graded of ‘excellent quality’ (i.e., moisture < 35%; fat-in-dry-matter > 47%). Full article

Nisin is a widely used natural antibacterial peptide in the food industry. However, its instability limits its practical application in food preservation. In this study, the antibacterial activity of previously built nisin/carboxylic curdlan (C6-Cc) complexes were tested against Gram-positive bacteria: Staphylococcus aureus. The results revealed that when the mass ratio of C6-Cc to nisin was 1:8 (C6-Cc: nisin, w/w), the nisin/C6-Cc complexes exhibited strong antibacterial stability over the pH range of 1–4, with inhibition zone diameters ranging from 11.5 to 13.0 mm and a minimum inhibitory concentration (MIC) of 0.71 mg/mL. Notably, the complexes also maintained good thermal stability even at 121 °C. Furthermore, the complexes with a mass ratio of 1:8 (w/w) showed superior physicochemical stability under low-pH conditions (pH < 5) within the salt concentration of 0–100 mM, and the stable temperature ranged from 25 to 121 °C. Twenty-eight days of storage had no significant impact on its antibacterial or physicochemical stability. These findings suggest that the nisin/C6-Cc complexes will have broad application prospects in food bio-preservation. Full article