An Overview of Antimicrobial Activity of Lysozyme and Its Functionality in Cheese

Genomic insights into the probiotic potential and genes linked to gallic acid metabolism in Pediococcus pentosaceus MBBL6 isolated from healthy cow milk

Pediococcus pentosaceus is well known for its probiotic properties, including roles in improving health, antimicrobial production, and enhancing fermented food quality. This study aimed to comprehensively analyze the whole genome of P. pentosaceus MBBL6, isolated from healthy cow milk, to assess its probiotic and antimicrobial potentials. P. pentosaceus MBBL6, isolated from a healthy cow milk at BSMRAU dairy farm, Gazipur, Bangladesh, underwent comprehensive genomic analysis, including whole genome sequencing, assembly, annotation, phylogenetic comparison, and assessment of metabolic pathways and secondary metabolites. Antimicrobial efficacy was evaluated through in-vitro and in-vivo studies, alongside in-silico exploration for potential mastitis therapy. We predicted 1,906 genes and 204 SEED sub-systems involved in carbohydrate metabolism and vitamin B complex biosynthesis, with a focus on lactose metabolism in MMBL6. Notably, 43 putative carbohydrate-active enzyme genes, including lysozymes, suggest the ability of MBBL6 for carbohydrate biotransformation and antimicrobial activity. The genome also revealed primary metabolic pathways for arginine and gallic acid metabolism and secondary metabolite gene clusters, including T3PKS and RiPP-like regions. Importantly, two bacteriocin biosynthesis gene clusters namely bovicin_255_variant and penocin_A, were identified in MBBL6. The safety assessment of MBBL6 genome revealed no virulence genes and a low pathogenicity score (0.196 out of 1.0). Several genes related to survival in gastrointestinal tract and colonization were also identified. Furthermore, MBBL6 exhibited susceptibility to a wide range of antibiotics in-vitro, and effectively suppressed mastitis pathogens in an in-vivo mouse mastitis model trial. The observed bacteriocin, particularly bovicin, demonstrated the ability to disrupt the function of an essential protein, Rho factor of mastitis pathogens by blocking transcription termination process. Taken together, our in-depth genomic analysis underscores the metabolic versatility, safety profile, and antimicrobial potential of P. pentosaceus MBBL6, suggesting its promise for applications in therapeutics, bioremediation, and biopreservation.

Enhancing safety and quality in the global cheese industry: A review of innovative preservation techniques

The global cheese industry faces challenges in adopting new preservation methods due to microbiological decay and health risks associated with chemical preservatives. Ensuring the safety and quality control of hard and semi-hard cheeses is crucial given their prolonged maturation and storage. Researchers are urged to create cheese products emphasizing safety, minimal processing, eco-labels, and clean labels to address consumer health and environmental worries. This review aims to explore effective strategies for ensuring the safety and quality of ripened cheeses, covering traditional techniques like aging, maturation, and salting, along with innovative methods such as modified and vacuum packaging, high-pressure processing, and active and intelligent packaging. Additionally, sustainable cheese preservation approaches, their impact on shelf life extension, and the physiochemical and quality attributes post-preservation are all analyzed. Overall, the cheese industry stands to benefit from this evaluation through enhanced market value, increased consumer satisfaction, and better environmental sustainability.The integration of novel preservation techniques in the cheese industry not only addresses current challenges but also paves the way for a more sustainable and consumer-oriented approach. By continually refining and implementing safety measures, quality control processes, and environmentally friendly practices, cheese producers can meet evolving consumer demands while ensuring the longevity and integrity of their products. Through a concerted effort to embrace innovation and adapt to changing market dynamics, the global cheese industry is poised to thrive in a competitive landscape where safety, quality, and sustainability are paramount.

A study to reveal the synergistic bacteriostatic potential of egg white lysozyme with carvacrol at the molecular level

The modification of proteins by bioactive molecules may have a synergistic enhancement effect on their respective functional properties. In this study, carvacrol (Car) was used to modify egg white lysozyme (LYZ) to improve its bacteriostatic ability. The results of microbiological experiments suggested that LYZ modified with Car had enhanced bacteriostatic activity against Escherichia coli (E. coli). The results of Ultraviolet-Visible (UV-VIS) absorption spectra expressed that Car and LYZ form a complex. Molecular docking of 100 compounds found that Car mostly acts in the hydrophobic cavity of LYZ. Molecular docking data confirmed the dominant role of van der Waals forces in the energy contribution of the LYZ-Car system, and molecular dynamics simulations showed that Car is relatively stable in the hydrophobic pocket of LYZ. Various types of spectral show that Car influences the tertiary and secondary structures of LYZ. Isothermal Titration Calorimetry (ITC) experiments found that the binding constant between Car and LYZ is 1.53 × 10-6 M. Differential Scanning Calorimetry (DSC) experiments demonstrate that this Car reduces the thermal stability of LYZ. The research findings contribute to the development and utilization of LYZ.

Disrupting Mycobacterium smegmatis biofilm using enzyme-immobilized rifampicin loaded silk fibroin nanoparticles for dual anti-bacterial and anti-biofilm action

Biofilm formation is a major challenge in the treatment of tuberculosis, leading to poor treatment outcomes and latent infections. The complex and dense extracellular polymeric substances (EPS) of the biofilm provides safe harbour for bacterium enabling persistence against anti-TB antibiotics. In this study, we demonstrated that rifampicin-encapsulated silk fibroin nanoparticles immobilized with antibiofilm enzymes can disrupt the Mycobacterium smegmatis biofilm and facilitate the anti-bacterial action of Rifampicin (RIF). The EPS of M.smegmatis biofilm predominantly comprised of lipids (48.8 ± 1.32 %) and carbohydrates (34.8 ± 4.70 %), similar to tuberculosis biofilms. Pre-formed biofilm eradication screening revealed that hydrolytic enzymes such as β-Glucosidase, Glucose oxidase, ɑ-Amylase, Acylase, and Phytase can exhibit biofilm eradication of M.smegmatis biofilms. The enzyme-mediated biofilm disruption was associated with a decrease in hydrophobicity of biofilm surfaces. Treatment with β-glucosidase and Phytase demonstrated a putative biofilm eradication by reducing the total carbohydrates and lipid composition without causing any significant bactericidal activity. Further, Phytase (250 μg/ml) and β-Glucosidase (112.5 ± 17.6 μg/ml) conjugated rifampicin-loaded silk fibroin nanoparticles (R-SFNs) exhibited an enhanced anti-bacterial activity against pre-formed M.smegmatis biofilms, compared to free rifampicin (32.5±7 μg/ml). Notably, treatment with β-glucosidase, Phytase and ɑ-amylase immobilized SFNs decreased the biofilm thickness by ∼98.84 % at 6h, compared to control. Thus, the study highlights that coupling anti-mycobacterial drugs with biofilm-eradicating enzymes such as amylase, phytase or β-glucosidase can be a potential strategy to improve the TB therapeutic outcomes.

Hydrogel microspheres encapsulating lysozyme/MXene for photothermally enhanced antibacterial activity and infected wound healing

The high mortality and enormous economic burden of bacterially infected wounds remains a huge challenge for human health. The development of ideal wound dressings with desirable antibacterial and good wound healing properties still remains a major problem affecting the regeneration of bacterially infected wound tissue. Herein, we present novel alginate-based hydrogel microspheres containing lysozyme and MXene (i-Lyso@Alg), in which the positively charged lysozyme is immobilized on the negatively charged MXene by electrostatic interaction. Due to the presence of MXene, i-Lyso@Alg exhibits good thermal effect, drug release behavior and strong antibacterial activity under near-infrared (NIR) irradiation. The synthesized i-Lyso@Alg can realize not only improvement of lysozyme stability but also photothermal responsive up-regulation for biocatalysis of lysozyme. The excellent antibacterial activities of i-Lyso@Alg were attributed to the photothermally enhanced lysozyme activity, assisted by bacterial death caused by local thermal effect of photothermally activated MXene and the physical damage due to the MXene. In addition, in the infected skin wounds of rats, i-Lyso@Alg + NIR significantly accelerates the wound healing process by inhibiting the expression of inflammatory factors and bacterial (Staphylococcus aureus) infection, and inducing the expression of pro-angiogenic factors and tissue remodeling. Overall, the results of this study introduce a pioneering approach by integrating the unique photothermal properties of MXene with the enzymatic action of lysozyme within an alginate-based hydrogel microsphere. This synergistic system not only advances the frontier of antibacterial wound dressings but also represents a significant step towards effective management of infected wounds, which possesses great potential in clinical treatment of infected wounds.

Biopolymer-polyphenol conjugates: Novel multifunctional materials for active packaging

The development of natural active packaging materials and coatings presents a promising alternative to petroleum-based packaging solutions. These materials are engineered by incorporating functional ingredients with preservative capabilities. Concurrently, research has highlighted the diverse physicochemical, functional, and health-promoting properties of protein-polyphenol, polysaccharide-polyphenol, and protein-polysaccharide-polyphenol conjugates within various food formulations. However, a critical gap exists regarding the exploration of these biopolymers as active packaging materials. In contrast to conventional approaches for developing active packaging materials, this review presents a novel perspective by focusing on biopolymer-polyphenol conjugates. In this work, we delve into the realm of active packaging materials and coatings constructed from these conjugates, highlighting their potential as multifunctional active components in food packaging and preservation. This review comprehensively investigates the physicochemical properties, functionalities, and health-promoting activities associated with biopolymer-polyphenol conjugates. Their emulsification, antioxidant, and antimicrobial activities, coupled with enhancements in mechanical strength and permeability properties, contribute to their multifunctional nature. Furthermore, we explore the potential advantages and limitations of utilizing these conjugates in active packaging applications. Finally, the review concludes by proposing crucial research avenues for further exploration of biopolymer-polyphenol conjugates within the domain of active food packaging.

Lysozyme-enhanced cellulose nanofiber, chitosan, and graphene oxide multifunctional nanocomposite for potential burn wound healing applications

The demand for advanced biomaterials in medical treatments is rapidly expanding. To address this demand, a nanocomposite of cellulose nanofiber (CNF) with chitosan (Ch) and graphene oxide (GO) was developed for burn wound treatment. The CNF-Ch-GO nanocomposites were characterized and their biological properties were evaluated. Microscopic images showed a uniform distribution of CNF, Ch, and GO with a porous structure. ATR-FTIR and XRD analyses confirmed the chemical structures, while a thermogravimetric study confirmed the stability of CNF-Ch-GO nanocomposite under a N2 atmosphere. The synthesized CNF-Ch-GO nanocomposite exhibited rapid absorption, absorbing 1781.7 ± 53.7 % PBS in 2 min. It demonstrated a Young's modulus of 11.90 ± 0.06 MPa in a hydrated condition, indicating its mechanical stability in water. Furthermore, it displayed excellent biocompatibility and hemocompatibility with 96.23 ± 12.21 % cell viability and 0.21 ± 0.08 % of hemolysis. Additionally, the blood clotting index of CNF-Ch-GO was comparable to that of standard dressing gauze. To enhance antimicrobial efficacy, CNF-Ch-GO was conjugated with lysozyme. This biotic and abiotic conjugation resulted in 92.17 % ± 3.02 % and 94.99 ± 2.1 % eradication of Escherichia coli and Staphylococcus aureus, respectively. The enhanced antimicrobial properties, biocompatibility, and mechanical stability of the superabsorbent CNF-Ch-GO nanocomposite indicate its significant potential for advanced burn wound healing applications.

Covalent Lysozyme Immobilization on Enzymatic Cellulose Nanocrystals

Nanostructured materials represent promising substrates for biocatalyst immobilization and activation. Cellulose nanocrystals (CNCs), accessible from waste and/or renewable sources, are sustainable and biodegradable, show high specific surface area for anchoring a high number of enzymatic units, and high thermal and mechanical stability. In this work, we present a holistic enzyme-based approach to functional antibacterial materials by bioconjugation between the lysozyme from chicken egg white and enzymatic cellulose nanocrystals. The neutral CNCs were prepared by endoglucanase hydrolysis from Avicel. We explore the covalent immobilization of lysozyme on enzymatic CNCs and on their TEMPO oxidized derivatives (TO-CNCs), comparing immobilization yields, material properties, and enzymatic activities. The materials were characterized by X-ray diffractometry (XRD), attenuated total reflectance Fourier Transform infrared spectroscopy (ATR-FTIR), bicinchoninic acid (BCA) assay, field-emission scanning electron microscopy (FE-SEM) and dynamic light scattering (DLS). We demonstrate the higher overall efficiency of the immobilization process carried out on TO-CNCs, based on the success of covalent bonding and on the stability of the isolated bioconjugates.

The activity of hydrolytic enzymes and antibiotics against biofilms of bacteria isolated from industrial-scale cooling towers

BACKGROUND

Cooling towers (CTs) are crucial to myriad industrial processes, supporting thermal exchange between fluids in heat exchangers using water from lakes and rivers as coolant. However, CT water can sometimes introduce microbial contaminants that adhere to and colonize various surfaces within the CT system. These microorganisms can form biofilms, significantly hindering the system's thermal exchange efficiency. Current treatment strategies employ oxidizing biocides to prevent microbial growth. However, despite their affordability, they do not eliminate biofilms effectively and can lead to corrosive damage within the system. Herein, we aim to devise an anti-biofilm strategy utilizing hydrolytic enzymes (such as α-amylase, glucoamylase, pectin-lyase, cellulase, protease, and DNase) alongside antibiotics (including meropenem, ciprofloxacin, gentamicin, erythromycin, chloramphenicol, and ceftriaxone) to combat microbial growth and biofilm formation in cooling systems.

RESULTS

All enzymes reduced the development of the biofilms significantly compared to controls (p < 0.05). The polysaccharidases exhibited biomass reduction of 90%, except for pectin-lyase (80%), followed by DNAse and protease at 43% and 49%, respectively. The antibiotics reduced the biofilms of 70% of isolates in concentration of > 2 mg/mL. The minimal biofilm eradication concentration (MBEC) lower than 1 mg/mL was detected for some 7-day-old sessile isolates. The enzymes and antibiotics were also used in combination against biofilms using the modified Chequerboard method. We found six synergistic combinations, with Fractional inhibitory concentrations (FIC) < 0.5, out of the ten tested. In the presence of the enzymatic mixture, MBECs presented a significant decrease (p < 0.05), at least 4-fold for antibiotics and 32-fold for enzymes. Moreover, we characterized high molecular weight (> 12 kDa) exopolysaccharides (EPS) from biofilms of ten isolates, and glycosyl composition analysis indicated a high frequency of glucose, mannose, erythrose, arabinose, and idose across isolates EPS contrasting with rhamnose, allose, and those carbohydrates, which were detected in only one isolate.

CONCLUSION

The synergistic approach of combining enzymes with antibiotics emerges as a highly effective and innovative strategy for anti-biofilm intervention, highlighting its potential to enhance biofilm management practices.

Combinatorial therapeutic enzymes to combat multidrug resistance in bacteria

AIMS

Antibiotic resistance including multidrug resistance (MDR) is a negative symbol to the human health system because it loses the capability to treat infections. Unfortunately, the available antibiotics do not show an effective therapeutic response against bacterial infections. In the situation of global antibiotic unresponsiveness, enzymatic therapy especially in combinatorial form seems an effective approach to control bacterial infection and combat resistance. The article is important because it focuses on combinatorial enzymatic therapy that has multiple properties (effective antibacterial performances, antibiofilm capacity, immunomodulators, targeted actions, synergistic actions, multiple targeting, and resistance-proof properties) and can address antibiotic resistance effectively.

MATERIALS AND METHODS

We searched the related topics with Pubmed, Scopus, and Google Scholar databases and finally 73 relevant papers were reviewed in detail and cited in this article.

KEY FINDINGS

Discusses properties of combinatorial therapeutic enzymes made it an accomplished means over antibiotic therapy. This article discusses the need for combinatorial enzymatic therapy against bacterial infection, its distinguished features, and properties with multi-mechanistic antibacterial action. It discussed the European Medicine Agency and Food and Drug Administration-approved therapeutic enzymes (antibacterial and antibiofilm).

SIGNIFICANCE

This article provided the possible combination of the enzyme that may be used as an antibacterial agent along with limitations and future scope of combinatorial antibacterial enzymatic agents. This article could draw the attention of researchers to combinatorial therapeutic enzymatic molecules as effective and futuristic therapy to overcome the problem of multiple antibiotic resistance in bacteria.

Leucine as a Moisture-Protective Excipient in Spray-Dried Protein/Trehalose Formulation

The incorporation of leucine (Leu), a hydrophobic amino acid, into pharmaceutically relevant particles via spray-drying can improve the physicochemical and particulate properties, stability, and ultimately bioavailability of the final product. More specifically, Leu has been proposed to form a shell on the surface of spray-dried (SD) particles. The aim of this study was to explore the potential of Leu in the SD protein/trehalose (Tre) formulation to control the water uptake and moisture-induced recrystallization of amorphous Tre, using lysozyme (LZM) as a model protein. LZM/Tre (1:1, w/w) was dissolved in water with varied amounts of Leu (0 - 40%, w/w) and processed by spray-drying. The solid form, residual moisture content (RMC), hygroscopicity, and morphology of SD LZM/Tre/Leu powders were evaluated, before and after storage under 22°C/55% RH conditions for 90 and 180 days. The X-ray powder diffraction results showed that Leu was in crystalline form when the amount of Leu in the formulation was at least 20% (w/w). Thermo-gravimetric analysis and scanning electron microscopy results showed that 0%, 5%, and 10% (w/w) Leu formulations led to comparable RMC and raisin-like round particles. In contrast, higher Leu contents resulted in a lower RMC and increased surface corrugation of the SD particles. Dynamic vapor sorption analysis showed that partial recrystallization of amorphous Tre to crystalline Tre·dihydrate occurred in the 0% Leu formulation. However, adding as little as 5% (w/w) Leu inhibited this recrystallization during the water sorption/desorption cycle. In addition, after storage, the formulations with higher Leu contents showed reduced water uptake. Instead of observing recrystallization of amorphous Tre in 0%, 5%, and 10% (w/w) Leu formulations, recrystallization of amorphous Leu was noted in the 5% and 10% (w/w) Leu formulations after storage. In summary, our study demonstrated that the addition of Leu has the potential to reduce water uptake and inhibit moisture-induced recrystallization of amorphous Tre in the SD protein/Tre powder system.

Efficient production of a highly active lysozyme from European flat oyster Ostrea edulis

Lysozyme, an antimicrobial agent, is extensively employed in the food and healthcare sectors to facilitate the breakdown of peptidoglycan. However, the methods to improve its catalytic activity and secretory expression still need to be studied. In the present study, twelve lysozymes from different origins were heterologously expressed using the Komagataella phaffii expression system. Among them, the lysozyme from the European flat oyster Ostrea edulis (oeLYZ) showed the highest activity. Via a semi-rational approach to reduce the structural free energy, the double mutant Y15A/S39R (oeLYZdm) with the catalytic activity 1.8-fold greater than that of the wild type was generated. Subsequently, different N-terminal fusion tags were employed to enhance oeLYZdm expression. The fusion with peptide tag 6×Glu resulted in a remarkable increase in the recombinant oeLYZdm expression, from 2.81 × 103 U mL-1 to 2.11 × 104 U mL-1 in shake flask culture, and eventually reaching 2.05 × 105 U mL-1 in a 3-L fermenter. The work produced the greatest amount of heterologous oeLYZ expression in microbial systems that are known to exist. Reducing the structural free energy and employing the N-terminal fusion tags are effective strategies to improve the catalytic activity and secretory expression of lysozyme.

Exploring the Potential of Postbiotics for Food Safety and Human Health Improvement

Food safety is a global concern, with millions suffering from foodborne diseases annually. The World Health Organization (WHO) reports significant morbidity and mortality associated with contaminated food consumption, and this emphasizes the critical need for comprehensive food safety measures. Recent attention has turned to postbiotics, metabolic byproducts of probiotics, as potential agents for enhancing food safety. Postbiotics, including organic acids, enzymes, and bacteriocins, exhibit antimicrobial and antioxidant properties that do not require live organisms, and this offers advantages over probiotics. This literature review critically examines the role of postbiotics in gut microbiome modulation and applications in the food industry. Through an extensive review of existing literature, this study evaluates the impact of postbiotics on gut microbiome composition and their potential as functional food ingredients. Research indicates that postbiotics are effective in inhibiting food pathogens such as Staphylococcus aureus, Salmonella enterica, and Escherichia coli, as well as their ability to prevent oxidative stress-related diseases, and they also show promise as alternatives to conventional food preservatives that can extend food shelf life by inhibiting harmful bacterial growth. Their application in functional foods contributes to improved gut health and reduced risk of foodborne illnesses. Findings suggest that postbiotics hold promise for improving health and preservation by inhibiting pathogenic bacteria growth and modulating immune responses.

A sensitive CRISPR/Cas12a-assisted fluorescent aptasensor for rapid detection of food allergens

Food allergens elicit abnormal immune system responses among allergic individuals and sensitive detection for allergenic ingredient is greatly significant. To address this need, a novel fluorescent aptasensor, assisted by Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR), have been developed for food allergens. In this study, aptamer offers distinctive recognition capabilities in binding specific targets, while CRISPR-associated-12a protein (Cas12a) holds precise cis-cleavage for cutting fluorescent signal probes. Notably, the utilization of Cas12a cis-cleavage activity, rather than trans-cleavage, eliminates the necessity for additional fluorescent probes, thus reducing interference between substances and enhancing sensitivity. Throughout the process, complementary DNA (cDNA) plays a crucial dual role in target recognition conversion and signal presentation, representing a key challenge and innovative aspect of this study. To evaluate the performance of the aptasensor, lysozyme (LYS) is employed as a representative model target of food allergens. Under optimal conditions, the developed aptasensor could achieve an exceptional low limit of detection (LOD) of 6.10 pM with a dynamic detection range of 10 pM-320 pM. The aptasensor demonstrates high selectivity and great recovery rates. This strategy yields promising outcomes, holding the potential to serve as a valuable reference for various food allergens detection.

Invited review: Role of Bacillus licheniformis in the dairy industry- friends or foes?

Bacillus licheniformis is one of the major spore-forming bacteria with great genotypic diversity in raw milk, dairy ingredients, final dairy products, and is found throughout the dairy processing continuum. Though being widely used as a probiotic strain, this species also serves as a potential risk in the dairy industry based on its roles in foodborne illness and dairy spoilage. Biofilm formation of B. licheniformis in combined with the heat resistance of its spores, make it impossible to prevent the presence of B. licheniformis in final dairy products by traditional cleaning and disinfection procedures. Despite the extensive efforts on the identification of B. licheniformis from various dairy samples, no reviews have been reported on both hazard and benefits of this spore-former. This review discusses the prevalence of B. licheniformis from raw milk to commercial dairy products, biofilm formation and spoilage potential of B. licheniformis, and its potential prevention methods. In addition, the potential benefits of B. licheniformis in the dairy industry were also summarized.

Natural Antimicrobials in Dairy Products: Benefits, Challenges, and Future Trends

This review delves into using natural antimicrobials in the dairy industry and examines various sources of these compounds, including microbial, plant, and animal sources. It discusses the mechanisms by which they inhibit microbial growth, for example, by binding to the cell wall's precursor molecule of the target microorganism, consequently inhibiting its biosynthesis, and interfering in the molecule transport mechanism, leading to cell death. In general, they prove to be effective against the main pathogens and spoilage found in food, such as Escherichia coli, Staphylococcus aureus, Bacillus spp., Salmonella spp., mold, and yeast. Moreover, this review explores encapsulation technology as a promising approach for increasing the viability of natural antimicrobials against unfavorable conditions such as pH, temperature, and oxygen exposure. Finally, this review examines the benefits and challenges of using natural antimicrobials in dairy products. While natural antimicrobials offer several advantages, including improved safety, quality, and sensory properties of dairy products, it is crucial to be aware of the challenges associated with their use, such as potential allergenicity, regulatory requirements, and consumer perception. This review concludes by emphasizing the need for further research to identify and develop effective and safe natural antimicrobials for the dairy industry to ensure the quality and safety of dairy products for consumers.

An innovative Pickering W/O/W nanoemulsion co-encapsulating hydrophilic lysozyme and hydrophobic Perilla leaf oil for extending shelf life of fish products

A Pickering water-in-oil-in-water nanoemulsion co-encapsulating lysozyme (LYS) and Perilla leaf oil (PO) was prepared using whey protein isolate-tannin acid conjugated nanoparticles (WPI-TA NPs) as emulsifiers, called LYS-PO-NE, and subsequently analyzed. The nano size and multiple phases was confirmed based on the results of confocal laser scanning microscope, scanning electron microscope, and droplet size analysis. LYS-PO-NE had high encapsulation efficiencies of 89.36 % (PO) and 43.91 % (LYS) and both could be released at a slow and continuous rate. The PO addition increased the droplet size, and the LYS addition delayed the release of PO. LYS-PO-NE also showed good storage, pH, thermal, and salt stability, and an effective combined bactericidal activity of LYS and PO against spoilage bacteria. Furthermore, the results of chilled salmon storage experiments indicated that LYS-PO-NE could extend the shelf life of chilled salmon to at least 6 days, demonstrating the potential in the shelf life for fish products.

The molecular modification, expression, and the antibacterial effects studies of human lysozyme

Human lysozyme (hLYZ) has attracted considerable research attention due to its natural and efficient antibacterial abilities and widespread uses. In this study, hLYZ was modified to enhance its enzyme activity and expressed in a Pichia pastoris expression system. A combination mutant HZM(2R-K)-N88D/V110S demonstrated the highest enzyme activity (6213 ± 164 U/mL) in shake flasks, which was 4.07-fold higher when compared with the original strain. Moreover, the recombinant P. pastoris was inducted in a 3 L bioreactor plus methanol/sorbitol co-feeding. After 120 h induction, the antibacterial activity of hLYZ reached 2.23 ± 0.12 × 105 U/mL, with the specific activity increasing to 1.89 × 105 U/mg, which is currently the highest specific activity obtained through recombinant expression of hLYZ. Also, hLYZ supernatants showed 2-fold inhibitory effects toward Staphylococcus aureus and Micrococcus lysodeikticus when compared with HZM(2R-K). Our research generated a hLYZ mutant with high antibacterial capabilities and provided a method for screening of high-quality enzymes.

A new perspective of frozen shoulder pathology; the interplay between the brain and the immune system

Frozen shoulder (FS), also known as adhesive capsulitis of the shoulder (FS), is a fibrotic inflammatory process of unknown etiology whose main symptoms are pain, stiffness and the loss of joint mobility. These symptoms may be associated with pathologies such as diabetes, Dupuytren's syndrome and the prevalence of today's sedentary lifestyle. This literature review provides an overview of the epidemiology and pathogenesis of this pathology, as well as the mechanisms of lowgrade chronic inflammation and infection, insulin resistance, and omics-science associated with it. We also propose a new hypothesis related to the possibility that the GABAergic system could play a decisive role in the development of frozen shoulder and that therefore diabetes type 1, endocrinological autoimmune disorders and frozen shoulder are connected by the same pathophysiological mechanisms. If that is true, the combined presence of psycho-emotional stress factors and pathogenic immune challenges could be the main causes of frozen shoulder syndrome. Finally, we propose a series of possible intervention strategies based on a multifactorial etiological and mechanistic concept.

Metal-Organic Framework Induced Stabilization of Proteins in Polymeric Nanoparticles

Developing protein confinement platforms is an attractive research area that not only promotes protein delivery but also can result in artificial environment mimicking of the cellular one, impacting both the controlled release of proteins and the fundamental protein biophysics. Polymeric nanoparticles (PNPs) are attractive platforms to confine proteins due to their superior biocompatibility, low cytotoxicity, and controllable release under external stimuli. However, loading proteins into PNPs can be challenging due to the potential protein structural perturbation upon contacting the interior of PNPs. In this work, we developed a novel approach to encapsulate proteins in PNPs with the assistance of the zeolitic imidazolate framework (ZIF). Here, ZIF offers an additional protection layer to the target protein by forming the protein@ZIF composite via aqueous-phase cocrystallization. We demonstrated our platform using a model protein, lysozyme, and a widely studied PNP composed of poly(ethylene glycol)-poly(lactic-co-glycolic acid) (PEG-PLGA). A comprehensive study via standard loading and release tests as well as various spectroscopic techniques was carried out on lysozyme loaded onto PEG-PLGA with and without ZIF protection. As compared with the direct protein encapsulation, an additional layer with ZIF prior to loading offered enhanced loading capacity, reduced leaching, especially in the initial stage, led to slower release kinetics, and reduced secondary structural perturbation. Meanwhile, the function, cytotoxicity, and cellular uptake of proteins encapsulated within the ZIF-bound systems are decent. Our results demonstrated the use of ZIF in assisting in protein encapsulation in PNPs and established the basis for developing more sophisticated protein encapsulation platforms using a combination of materials of diverse molecular architectures and disciplines. As such, we anticipate that the protein-encapsulated ZIF systems will serve as future polymer protein confinement and delivery platforms for both fundamental biophysics and biochemistry research and biomedical applications where protein delivery is needed to support therapeutics and/or nutrients.

Antimicrobial Properties of Colostrum and Milk

The growing number of antibiotic resistance genes is putting a strain on the ecosystem and harming human health. In addition, consumers have developed a cautious attitude towards chemical preservatives. Colostrum and milk are excellent sources of antibacterial components that help to strengthen the immunity of the offspring and accelerate the maturation of the immune system. It is possible to study these important defenses of milk and colostrum, such as lactoferrin, lysozyme, immunoglobulins, oligosaccharides, etc., as biotherapeutic agents for the prevention and treatment of numerous infections caused by microbes. Each of these components has different mechanisms and interactions in various places. The compound's mechanisms of action determine where the antibacterial activity appears. The activation of the antibacterial activity of milk and colostrum compounds can start in the infant's mouth during lactation and continue in the gastrointestinal regions. These antibacterial properties possess potential for therapeutic uses. In order to discover new perspectives and methods for the treatment of bacterial infections, additional investigations of the mechanisms of action and potential complexes are required.

Expression of BSN314 lysozyme genes in Escherichia coli BL21: a study to demonstrate microbicidal and disintegarting potential of the cloned lysozyme

This study is an extension of our previous studies in which the lysozyme was isolated and purified from Bacillus subtilis BSN314 (Naveed et al., 2022; Naveed et al., 2023). In this study, the lysozyme genes were cloned into the E. coli BL21. For the expression of lysozyme in E. coli BL21, two target genes, Lyz-1 and Lyz-2, were ligated into the modified vector pET28a to generate pET28a-Lyz1 and pET28a-Lyz2, respectively. To increase the production rate of the enzyme, 0.5-mM concentration of IPTG was added to the culture media and incubated at 37 °C and 220 rpm for 24 h. Lyz1 was identified as N-acetylmuramoyl-L-alanine amidase and Lyz2 as D-alanyl-D-alanine carboxypeptidase. They were purified by multi-step methodology (ammonium sulfate, precipitation, dialysis, and ultrafiltration), and antimicrobial activity was determined. For Lyz1, the lowest MIC/MBC (0.25 μg/mL; with highest ZOI = 22 mm) were recorded against Micrococcus luteus, whereas the highest MIC/MBC with lowest ZOI were measured against Salmonella typhimurium (2.50 μg /mL; with ZOI = 10 mm). As compared with Aspergillus oryzae (MIC/MFC; 3.00 μg/mL), a higher concentration of lysozyme was required to control the growth of Saccharomyces cerevisiae (MIC/MFC; 50 μg/mL). Atomic force microscopy (AFM) was used to analyze the disintegrating effect of Lyz1 on the cells of selected Gram-positive bacteria, Gram-negative bacteria, and yeast. The AFM results showed that, as compared to Gram-negative bacteria, a lower concentration of lysozyme (Lyz1) was required to disintegrate the cell of Gram-positive bacteria.

From phyllosphere to insect cuticles: silkworms gather antifungal bacteria from mulberry leaves to battle fungal parasite attacks

BACKGROUND

Bacterial transfers from plants to insect herbivore guts have been well investigated. However, bacterial exchanges between plant phyllospheres and insect cuticles remain unclear, as does their related biological function.

RESULTS

Here, we report that the cuticular bacterial loads of silkworm larvae quickly increased after molting and feeding on the white mulberry (Morus alba) leaves. The isolation and examination of silkworm cuticular bacteria identified one bacterium Mammaliicoccus sciuri that could completely inhibit the spore germination of fungal entomopathogens Metarhizium robertsii and Beauveria bassiana. Interestingly, Ma. sciuri was evident originally from mulberry leaves, which could produce a secreted chitinolytic lysozyme (termed Msp1) to damage fungal cell walls. In consistency, the deletion of Msp1 substantially impaired bacterial antifungal activity. Pretreating silkworm larvae with Ma. sciuri cells followed by fungal topical infections revealed that this bacterium could help defend silkworms against fungal infections. Unsurprisingly, the protective efficacy of ΔMsp1 was considerably reduced when compared with that of wild-type bacterium. Administration of bacterium-treated diets had no negative effect on silkworm development; instead, bacterial supplementation could protect the artificial diet from Aspergillus contamination.

CONCLUSIONS

The results of this study evidence that the cross-kingdom transfer of bacteria from plant phyllospheres to insect herbivore cuticles can help protect insects against fungal parasite attacks. Video Abstract.

Effects of Dietary Supplementation of Essential Oils, Lysozyme, and Vitamins' Blend on Layer Hen Performance, Viral Vaccinal Response, and Egg Quality Characteristics

Maintaining respiratory tract health is crucial for layers, impacting gut health, laying performance, and egg quality. Viral diseases and standard vaccinations can compromise tracheal epithelium function, leading to oxidative stress. This study assessed the impact of a blend of feed additives, predominantly lysozyme (L), essential oils (EO), and vitamins (VIT) (referred to as L + EO + VIT), on young layers during an oral vaccination schedule. The supplementation significantly enhanced antibody titers for Newcastle Disease Virus (NDV) and Infectious Bronchitis Virus (IBV) after vaccination, trachea functionality and intestinal health in the jejunum, increased egg production, and exhibited a trend toward higher egg weight. Although feed intake showed no significant difference, egg quality remained consistent across experimental groups. Moreover, L + EO + VIT supplementation elevated total phenolic content in eggs, improving oxidative stability in both fresh and stored eggs, particularly under iron-induced oxidation. Notably, it substantially reduced yolk lipid peroxidation and albumen protein carbonyls. In conclusion, water supplementation with L + EO + VIT may enhance humoral immune response to IBV and NDV, positively impacting hen productivity. These findings indicate improved tracheal function and enhanced oxidative stability, emphasizing the potential of this blend in promoting overall health and performance in layers.

Effect of dietary supplementation with recombinant human lysozyme on growth performance, antioxidative characteristics, and intestinal health in broiler chickens

Lysozyme is often used as a feed additive to act as an antibacterial protein that boosts the immune system of livestock and poultry while protecting against pathogens. To investigate the effects of recombinant human lysozyme (rhLYZ) from Pichia pastoris and chlortetracycline on broiler chicken's production performance, antioxidant characteristics, and intestinal microbiota, a total of 200, 1-d-old male Arbor Acres broiler chickens (46.53 ± 0.42 g) were selected for a 42-d experiment. Dietary treatments included a basal diet of corn-soybean meal supplemented with either 0 mg/kg (CON), 50 mg/kg aureomycin (ANT), 20 mg/kg rhLYZ (LOW), 60 mg/kg rhLYZ (MEDIUM), or 180 mg/kg rhLYZ (HIGH). Compared with CON, MEDIUM diet increased (P < 0.05) average daily gain (67.40 g) of broilers from day 22 to 42. In the early (1.29) and overall phases (1.69), MEDIUM led to a reduction (P < 0.05) in the feed conversion ratio of broiler chickens. Furthermore, in comparison to the CON and ANT, MEDIUM exhibited reduced (P < 0.05) levels of INF-γ and tumor necrosis factor-α in the serum. In the cecum, the abundance of Monoglobus and Family_XIII_AD3011_group was lower (P < 0.05) in the MEDIUM treatment compared to CON. Overall, supplementation of 60 mg/kg of rhLYZ improved growth performance, nutrient utilization efficiency, and serum immune function, while also influencing the composition of intestinal microbiota. This suggests lysozyme's potential to replace antibiotic additives in feed.

pH-Dependent HEWL-AuNPs Interactions: Optical Study

Optical methods (spectroscopy, spectrofluorometry, dynamic light scattering, and refractometry) were used to study the change in the state of hen egg-white lysozyme (HEWL), protein molecules, and gold nanoparticles (AuNPs) in aqueous colloids with changes in pH, and the interaction of protein molecules with nanoparticles was also studied. It was shown that changing pH may be the easiest way to control the protein corona on gold nanoparticles. In a colloid of nanoparticles, both in the presence and absence of protein, aggregation-deaggregation, and in a protein colloid, monomerization-dimerization-aggregation are the main processes when pH is changed. A specific point at pH 7.5, where a transition of the colloidal system from one state to another is observed, has been found using all the optical methods mentioned. It has been shown that gold nanoparticles can stabilize HEWL protein molecules at alkaline pH while maintaining enzymatic activity, which can be used in practice. The data obtained in this manuscript allow for the state of HEWL colloids and gold nanoparticles to be monitored using one or two simple and accessible optical methods.

Nanostructured Antimicrobials for Quality and Safety Improvement in Dairy Products

In the food sector, one of the most important economic activities is the dairy industry, which has been facing many challenges in order to meet the increasing demand by consumers for natural and minimally processed products with high quality. In this sense, the application of innovative and emerging technologies can be an interesting alternative, for example, the use of nanotechnology in packaging and as delivery systems. This technology has the potential to improve the quality and safety of dairy products, representing an interesting approach for delivering food preservatives and improving the mechanical, barrier and functional properties of packaging. Several applications and promising results of nanostructures for dairy product preservation can be found throughout this review, including the use of metallic and polymeric nanoparticles, lipid-based nanostructures, nanofibers, nanofilms and nanocoatings. In addition, some relevant examples of the direct application of nanostructured natural antimicrobials in milk and cheese are presented and discussed, as well as the use of milk agar as a model for a preliminary test. Despite their high cost and the difficulties for scale-up, interesting results of these technologies in dairy foods and packaging materials have promoted a growing interest of the dairy industry.

Pharmacological Modulation of Host Immunity with Hen Egg White Lysozyme (HEWL)-A Review

In the 100 years since its discovery, lysozyme has become an important molecule, both as model for studies in different fields and as a candidate for the therapy of various pathological conditions. Of the dozens of known lysozymes, in this review we focus on one in particular, lysozyme extracted from hen egg white (HEWL), and its interaction with the immune system when it is administered orally. Experimental data show that there is an axis that directs immune system activation from GALT (gut-associated lymphoid tissue) and the intestinal lymphocyte clusters. Although a contribution of peptidoglycans from digestion of the bacterial cell wall in the intestinal lumen cannot be excluded, immune stimulation is not dependent on the enzymatic activity of HEWL. The immune responses suggest that HEWL is able to recover from immunodepression caused by tumor growth or immunosuppressants, and that it also improves the success of chemotherapy. The positive results obtained in a small Phase 2 study in patients, the ease of oral administration of this protein, and the absence of adverse effects suggest that HEWL may play an important role in all diseases where the immune system is weakened or where its enhancement plays a critical role in the resolution of the pathology.

Inhibitory-like Substances Produced by Yeasts Isolated from Andean Blueberries: Prospective Food Antimicrobials

Natural agents from microorganisms have emerged as suitable options to replace chemical preservatives in foods. In this study, the antibacterial activity of cell-free supernatant (CFS) from five native yeasts (Saccharomyces cerevisiae Lev6 and Lev30, C. pseudointermedia Lev8, Candida intermedia Lev9, C. parapsilosis Lev15) and the reference S. boulardi SSB, was evaluated against some indicator food pathogens. The generation of antimicrobials was reliant on strain-, and sugar-supplemented media, which supported yeast growth established at 30 °C and 200 rpm for 48 h. Treatment with proteinase K and catalase was unable to completely abolish the inhibitory effect, indicating that the active components are likely complex combinations of acids, proteins, hydrogen peroxide, and other metabolites. Although there was no impact on Listeria monocytogenes, exposure to CFS and extracellular fractions obtained through precipitation with methanol (PPm) at 120 °C for 60 min significantly (p < 0.05) increased the inhibitory activity against Escherichia coli, Salmonella enterica, Kosakonia cowanii, and Staphylococcus aureus, indicating that the inhibitory activity was stimulated by heat. Likewise, a synergistic inhibitory action against Listeria was obtained following the pretreatment of PPm with EDTA (ethylenediaminetetraacetic acid). These activities were yeast strain-dependent, with Lev6, Lev8, and Lev30 showing the highest activity. In addition, a heat-stable low-molecular-mass molecule under 5 kDa was detected in Lev30. Further research is required to evaluate the mode of action and characterize the composition of the released molecules in the CFS in order to develop a novel biocontrol agent based on yeasts.

Inhibition of primary and secondary nucleation alongwith disruption of amyloid fibrils and alleviation of associated cytotoxicity: A biophysical insight of a novel property of Chlorpropamide (an anti-diabetic drug)

Aggregation of physiologically synthesized soluble proteins to insoluble, cytotoxic fibrils is a pre-requisite for pathogenesis of amyloid associated disorders including Alzheimer's disease, non-systemic amyloidosis, Parkinson's disease, etc. Considerable advancement has been made to understand the mechanism behind aggregation process but till date we have no efficient cure and preventive therapy for associated diseases. Strategies to prevent protein aggregation are nevertheless many which have been proved promisingly successful in vitro. One of those is repurposing already approved drugs that saves time and money too and has been employed in this study. Here, for the first time we are reporting the effectiveness of an anti-diabetic drug chlorpropamide (CHL) under dosage conditions, a novel property to inhibit aggregation in human lysozyme (HL) in vitro. Spectroscopic (Turbidity, RLS, ThT, DLS, ANS) and microscopic (CLSM) results demonstrates that CHL has the potency to suppress aggregation in HL up to 70 %. CHL is shown to affect the elongation of fibrils with IC₅₀ value of 88.5 μM as clear from the kinetics results, may be by interacting near/with aggregation prone regions of HL. Hemolytic assay also revealed the reduced cytotoxicity in the presence of CHL. Disruption of amyloid fibrils and inhibition of secondary nucleation in the presence of CHL was also evidenced by ThT, CD and CLSM results with reduced cytotoxicity as confirmed by hemolytic assay. We also performed preliminary studies on α-synuclein fibrillation inhibition and surprisingly found that CHL is not just inhibiting the fibrillation but also stabilizing the protein in its native state. These findings insinuate that CHL (anti-diabetic) possess multiple roles and can be a promising drug for developing therapeutic against non-systemic amyloidosis, Parkinson's disease and other amyloid associated disorders.

Biodegradable Polymers and Polymer Composites with Antibacterial Properties

Antibiotic resistance is one of the greatest threats to global health and food security today. It becomes increasingly difficult to treat infectious disorders because antibiotics, even the newest ones, are becoming less and less effective. One of the ways taken in the Global Plan of Action announced at the World Health Assembly in May 2015 is to ensure the prevention and treatment of infectious diseases. In order to do so, attempts are made to develop new antimicrobial therapeutics, including biomaterials with antibacterial activity, such as polycationic polymers, polypeptides, and polymeric systems, to provide non-antibiotic therapeutic agents, such as selected biologically active nanoparticles and chemical compounds. Another key issue is preventing food from contamination by developing antibacterial packaging materials, particularly based on degradable polymers and biocomposites. This review, in a cross-sectional way, describes the most significant research activities conducted in recent years in the field of the development of polymeric materials and polymer composites with antibacterial properties. We particularly focus on natural polymers, i.e., polysaccharides and polypeptides, which present a mechanism for combating many highly pathogenic microorganisms. We also attempt to use this knowledge to obtain synthetic polymers with similar antibacterial activity.

The Impact of Processing and Extraction Methods on the Allergenicity of Targeted Protein Quantification as Well as Bioactive Peptides Derived from Egg

This review article discusses advanced extraction methods to enhance the functionality of egg-derived peptides while reducing their allergenicity. While eggs are considered a nutrient-dense food, some proteins can cause allergic reactions in susceptible individuals. Therefore, various methods have been developed to reduce the allergenicity of egg-derived proteins, such as enzymatic hydrolysis, heat treatment, and glycosylation. In addition to reducing allergenicity, advanced extraction methods can enhance the functionality of egg-derived peptides. Techniques such as membrane separation, chromatography, and electrodialysis can isolate and purify specific egg-derived peptides with desired functional properties, improving their bioactivity. Further, enzymatic hydrolysis can also break down polypeptide sequences and produce bioactive peptides with various health benefits. While liquid chromatography is the most commonly used method to obtain individual proteins for developing novel food products, several challenges are associated with optimizing extraction conditions to maximize functionality and allergenicity reduction. The article also highlights the challenges and future perspectives, including optimizing extraction conditions to maximize functionality and allergenicity reduction. The review concludes by highlighting the potential for future research in this area to improve the safety and efficacy of egg-derived peptides more broadly.

Computational Insight into Intraspecies Distinctions in Pseudoalteromonas distincta: Carotenoid-like Synthesis Traits and Genomic Heterogeneity

Advances in the computational annotation of genomes and the predictive potential of current metabolic models, based on more than thousands of experimental phenotypes, allow them to be applied to identify the diversity of metabolic pathways at the level of ecophysiology differentiation within taxa and to predict phenotypes, secondary metabolites, host-associated interactions, survivability, and biochemical productivity under proposed environmental conditions. The significantly distinctive phenotypes of members of the marine bacterial species Pseudoalteromonas distincta and an inability to use common molecular markers make their identification within the genus Pseudoalteromonas and prediction of their biotechnology potential impossible without genome-scale analysis and metabolic reconstruction. A new strain, KMM 6257, of a carotenoid-like phenotype, isolated from a deep-habituating starfish, emended the description of P. distincta, particularly in the temperature growth range from 4 to 37 °C. The taxonomic status of all available closely related species was elucidated by phylogenomics. P. distincta possesses putative methylerythritol phosphate pathway II and 4,4'-diapolycopenedioate biosynthesis, related to C30 carotenoids, and their functional analogues, aryl polyene biosynthetic gene clusters (BGC). However, the yellow-orange pigmentation phenotypes in some strains coincide with the presence of a hybrid BGC encoding for aryl polyene esterified with resorcinol. The alginate degradation and glycosylated immunosuppressant production, similar to brasilicardin, streptorubin, and nucleocidines, are the common predicted features. Starch, agar, carrageenan, xylose, lignin-derived compound degradation, polysaccharide, folate, and cobalamin biosynthesis are all strain-specific.

Spectro-kinetic investigations on the release mechanism of lysozyme from layer-by-layer reservoirs

The investigations of protein adsorption and release on interfaces aid in the elucidation of the protein-surface interaction mechanism, which has several applications in the biomedical area. The spectro-kinetic and morphological analysis of the release of lysozyme (Lyz) from chitosan/polystyrene sulphonate (CHI/PSS) multilayer immobilized at pHs 10.6, 8.8 and 5.0 shows that the extent of release strongly depends on the pH of Lyz loading and the ionic strength of the desorbing solution. When compared to pH 8.8, the release for pH 10.6 achieves equilibrium more rapidly. At loading pH 10.6, the release is surface-mediated, at pH 8.8, it is both surface- and bulk-mediated, while at pH 5.0 it is bulk mediated with minimal release. Lyz released for loading pH 10.6 retains its native secondary structure. Kinetic fitting suggests that high loading pH 8.8-10.6 and high release ionic strength (0.5-1.0 M NaCl) lead to burst release of Lyz from CHI/PSS multilayer. Surface morphology changes of multilayer interface upon Lyz loading and release are highlighted by SEM topography and AFM height distribution analysis. The present work indicates that CHI/PSS multilayer system can function as a reservoir for burst as well as controlled release of lysozyme by selecting the loading pH and ionic strength.

Antimicrobial Compounds in Food Packaging

This review presents current knowledge on antimicrobial agents that are already used in the food packaging industry. At the beginning, innovative ways of food packaging were discussed, including how smart packaging differs from active packaging, and what functions they perform. Next, the focus was on one of the groups of bioactive components that are used in these packaging, namely antimicrobial agents. Among the antimicrobial agents, we selected those that have already been used in packaging and that promise to be used elsewhere, e.g., in the production of antimicrobial biomaterials. Main groups of antimicrobial agents (i.e., metals and metal oxides, organic acids, antimicrobial peptides and bacteriocins, antimicrobial agents of plant origin, enzymes, lactoferrin, chitosan, allyl isothiocyanate, the reuterin system and bacteriophages) that are incorporated or combined with various types of packaging materials to extend the shelf life of food are described. The further development of perspectives and setting of new research directions were also presented.

Effect of the Structure of Magnetic Nanocomposite Adsorbents on the Lysozyme Separation Efficiency

In this study, we prepared various anionic magnetic adsorbents through the carboxyl functionalization of core/shell-structured Fe₃O₄/SiO₂ (FS) particles by either succinic anhydride (FSC), low-molecular-weight (MW 1800) polyacrylic acid (PAA) (FSP1), or high-molecular-weight (MW 100,000) PAA (FSP2), and then, investigated the effect of the structure of adsorbents and operational parameters on their performance for the lysozyme separation. The type and size of functional molecules have significant effects on the surface concentration of functional carboxyl groups onto the adsorbent particles (increase in the order of FSP2 > FSP1 > FSC), and consequently on the adsorption efficiency (AE) (∼100, 98, and 62%, respectively) and adsorption capacity (AC) (∼1000, 980, and 621 mg·g^-1, respectively) of the adsorbents. However, the loss of the antibacterial activity of separated lysozyme molecules due to the molecular conformational change increased in the order of FSP2 > FSP1 = FSC, as compared to the free lysozyme. The application of basic buffer solutions for the elution of adsorbed enzyme molecules resulted in more adverse effects on the enzyme activity. The obtained results recommend that FSP1 can be used as a suitable anionic adsorbent for the isolation of positively charged proteins, owing to its high adsorption capacity, excellent reusability, and structural stability, as well as the high purity, structural stability, and activity recovery of the isolated proteins.

Temperature Induced Gelation and Antimicrobial Properties of Pluronic F127 Based Systems

Different formulations containing Pluronic F127 and polysaccharides (chitosan, sodium alginate, gellan gum, and κ-carrageenan) were investigated as potential injectable gels that behave as free-flowing liquid with reduced viscosity at low temperatures and displayed solid-like properties at 37 °C. In addition, ZnO nanoparticles, lysozyme, or curcumin were added for testing the antimicrobial properties of the thermal-sensitive gels. Rheological investigations evidenced small changes in transition temperature and kinetics of gelation at 37 °C in presence of polysaccharides. However, the gel formation is very delayed in the presence of curcumin. The antimicrobial properties of Pluronic F127 gels are very modest even by adding chitosan, lysozyme, or ZnO nanoparticles. A remarkable enhancement of antimicrobial activity was observed in the presence of curcumin. Chitosan addition to Pluronic/curcumin systems improves their viscoelasticity, antimicrobial activity, and stability in time. The balance between viscoelastic and antimicrobial characteristics needs to be considered in the formulation of Pluronic F127 gels suitable for biomedical and pharmaceutical applications.

Caco-2 Cell Response Induced by Peptides Released after Digestion of Heat-Treated Egg White Proteins

The heat treatment of food proteins induces structural modifications that influence their interaction with human fluids and cells. We aimed to evaluate the Caco-2 cell response induced by peptides produced after digestion of heat-treated egg white proteins. In vitro digestion of ovalbumin (OVA), ovomucoid (OM), and lysozyme (LYS), untreated or previously heated, was performed. The digestibility of proteins and the response of Caco-2 cells exposed to peptides (<10 kDa) generated during digestion were evaluated. Intact OVA and LYS persisted after the digestion of native proteins, whereas OM was completely hydrolysed. A heat treatment at 65 °C for 30 min did not alter the digestibility of OVA, whereas at 90 °C for 3 min, protein degradation was favoured. The digestibility of OM and LYS was not affected by heat treatment. Peptides derived from OVA and OM digestion induced IL-6 and IL-8 production. OVA and LYS digestion promoted the expression of Tslp, and Il6 and Il33, respectively. A heat treatment prior to OVA digestion reduced IL-6 production and Tslp expression. It was concluded that heat treatments can reduce the release of OVA-derived peptides, but not OM and LYS, with proinflammatory activity during digestion.

Inhibitory Effect of Epigallocatechin Gallate-Silver Nanoparticles and Their Lysozyme Bioconjugates on Biofilm Formation and Cytotoxicity

Biofilms are multicellular communities of microbial cells that grow on natural and synthetic surfaces. They have become the major cause for hospital-acquired infections because once they form, they are very difficult to eradicate. Nanotechnology offers means to fight biofilm-associated infections. Here, we report on the synthesis of silver nanoparticles (AgNPs) with the antibacterial ligand epigallocatechin gallate (EGCG) and the formation of a lysozyme protein corona on AgNPs, as shown by UV-vis, dynamic light scattering, and circular dichroism analyses. We further tested the activity of EGCG-AgNPs and their lysozyme bioconjugates on the viability of Bacillus subtilis cells and biofilm formation. Our results showed that, although EGCG-AgNPs presented no antibacterial activity on planktonic B. subtilis cells, they inhibited B. subtilis biofilm formation at concentrations larger than 40 nM, and EGCG-AgNP-lysozyme bioconjugates inhibited biofilms at concentrations above 80 nM. Cytotoxicity assays performed with human cells showed a reverse trend, where EGCG-AgNPs barely affected human cell viability while EGCG-AgNP-lysozyme bioconjugates severely hampered viability. Our results therefore demonstrate that EGCG-AgNPs may be used as noncytotoxic antibiofilm agents.