Search Results (66)

This review presents information obtained over the past 10 years on the methods to control the widespread worldwide phytopathogen Pectobacterium carotovorum subsp. carotovorum (Pcc). This bacterium is among the ten most dangerous phytopathogens; it affects a wide range of cultivated plants: vegetables, ornamental and medicinal crops, both during vegetation and during the storage of fruits. Symptoms of Pcc damage include the wilting of plants, blackening of vessels on leaves, stems and petioles. At the flowering stage, the stem core gradually wilts and, starting from the root, the stem breaks and the plant dies. Pcc is a rod-shaped, non-capsule and endospore-forming facultative anaerobic Gram-negative bacterium with peritrichous flagellation. Pcc synthesizes bacteriocins—carocins. The main virulence factors of Pcc are the synthesis of N-acyl-homoserine lactone (AHL) and plant cell wall-degrading enzymes (PCWDEs) (pectinases, polygalacturonases, cellulases, and proteases). Diagnostic methods for this phytopathogen include polymerase chain reaction (PCR), loop-mediated isothermal amplification (LAMP), multilocus genotyping of strain-specific genes and detection of unique volatile organic compounds (VOCs). The main methods to control this microorganism include the use of various chemicals (acids, phenols, esters, salts, gases), plant extracts (from grasses, shrubs, trees, and algae), antagonistic bacteria (Bacillus, Pseudomonas, Streptomyces, and lactic acid bacteria), viruses (including a mixture of bacteriophages), and nanomaterials based on metals and chitosan. Full article

The applicability of free and encapsulated DNA as tracers in surface water studies in Lithuanian climatic conditions was evaluated. Tracer DNA synthesis and analysis were performed using real-time polymerase chain reaction (RT-PCR). Alginate and chitosan were used to obtain the microcapsules with DNA, and their sizes were determined using an atomic force microscopy. The Murlė stream in the city of Vilnius was chosen for field experiments using the prepared tracers. It was found that both types of tracers may be applied to surface water studies, but the relative concentration recovery of encapsulated DNA tracers is 3–6 times higher than that of free DNA tracers. It was concluded that the alginate/chitosan capsules protect DNA from the sandy layer in Murlė stream, direct UV exposure and other environmental factors that could degrade DNA. To our knowledge, this is the first report about free and encapsulated DNA tracer application in surface water studies in Lithuania. Full article

Drought and metal pollution severely impact plant growth. Root-associated extremophilic fungi can improve plant performance, and their encapsulation improves protection and effectiveness. This study optimized the encapsulation conditions for an extremophilic fungus with plant growth-promoting traits using alginate–chitosan capsules. An endophytic fungus was isolated from the roots of Neltuma chilensis from the Atacama Desert and identified via internal transcribed spacer (ITS) sequencing. Its plant growth-promoting traits, including exopolysaccharide, ammonium, siderophore, and indole acetic acid production and phosphorus solubilization, were evaluated. Freeze-dried Penicillium nalgiovense was encapsulated using jet-breaking extrusion, and capsule morphology and fungal survival were assessed via scanning electron microscope (SEM), confocal laser scanning microscopy (CLSM), and viability tests. Using Taguchi’s design, optimal conditions for sphericity (0.914 ± 0.002) and mean size (3.232 ± 0.087 mm) were achieved with 1% chitosan, a 5 cm distance to the gelation bath, and a 40 Hz vibration frequency. CLSM analysis confirmed the presence of the chitosan outer layer, revealing the capsule’s coating material encapsulating the fungus P. nalgiovense. The encapsulated fungus remained viable across disinfection times, demonstrating effective protection and gradual release. These findings emphasize the need for precise parameter control in fungal encapsulation, providing a basis for developing robust bioinoculants to support plant resilience in extreme environments. Full article

Background/Objectives: Porcine epidemic diarrhea (PED) is a highly contagious enteric infectious disease that causes severe morbidity and mortality in piglets, posing significant economic losses to the swine industry worldwide. Oral vaccines based on Lactococcus lactis offer a promising approach due to their safety and genetic manipulability. This study aims to develop and evaluate an oral L. lactis-based vaccine expressing the full-length PEDV S protein. Methods: A recombinant L. lactis strain expressing the PEDV S protein was constructed and encapsulated in alginate–chitosan microcapsules. Vaccine stability was tested in simulated digestive fluids, and mice were orally immunized. Immune responses were evaluated by measuring specific antibodies, cytokines, and lymphocyte proliferation. Results: The recombinant L. lactis NZ3900/pNZ8149-S strain successfully expressed the full-length PEDV S protein and maintained stable plasmid inheritance. Oral immunization in mice induced detectable PEDV-specific immune responses. Both encapsulated and non-encapsulated vaccines stimulated the production of IgG and sIgA antibodies, as well as cytokines associated with Th1 and Th2 responses. Notably, encapsulation with alginate–chitosan significantly enhanced bacterial survival in digestive conditions and further amplified immune responses, including higher antibody titers, elevated levels of IFN-γ, IL-4, and IL-10, and greater lymphocyte proliferation, indicating improved immune memory. Conclusions: The oral L. lactis NZ3900/pNZ8149-S vaccine expressing the PEDV S protein effectively induced systemic and mucosal immunity in mice. Encapsulation with alginate–chitosan further enhanced its immunogenicity and stability in gastrointestinal conditions. These results suggest that both the engineered L. lactis strain and the encapsulation strategy contribute to the development of a promising oral vaccine platform for controlling PEDV in swine populations. Full article

Hydrogel delivery systems are popular dosage forms that have a number of advantages, such as ease of use, painlessness, increased efficiency due to prolongation of rheological, swelling and sorption characteristics, regulation of drug release, and stimulus sensitivity. Particular interest is shown in hydrogels of cellulose ether derivatives due to the possibility of obtaining their modified forms to vary the solubility, the degree of prolonged action, and the release of the active substance, as well as their widespread availability, affordability, and the possibility of sourcing raw materials from different sources. Hydroxypropyl methylcellulose (HPMC, “hypromellose”) is one of the most popular cellulose ethers in the production of medicines as a filler, coating and carrier. Research on hydrogel carriers based on polymer complexes and modified forms of HPMC using acrylic, citric, and lactic acids, PVP, chitosan, Na-CMC, and gelatin is of particular interest, as they provide the necessary rheological and swelling characteristics. There is growing interest in medical transdermal hydrogels, films, capsules, membranes, nanocrystals, and nanofibers based on HPMC with the incorporation of biologically active substances (BASs), especially those of plant origin, as antibacterial, wound-healing, antimicrobial, mucoadhesive, anti-inflammatory, and antioxidant agents. The aim of this article is to review modern research and achievements in the field of hydrogel systems based on cellulose ethers, particularly HPMC, analyzing their properties, methods of production, and prospects for application in medicine and pharmacy. Full article

This study is a comparative investigation of the activity of unloaded and curcumin-loaded oil-in-water emulsion or chitosan-based capsules on rabbit retinal cells (RRC), coronavirus HCoV-OC43, and virus HSV-1 virus in relation to their potential ophthalmologic applications. The carriers are developed by using well-established experimental procedures. The characterization of their surface properties and stability in simulated ocular fluids (tear fluid, aqueous humor, and vitreous humor) is performed using the dynamic light scattering method and UV–vis spectrophotometry. In vitro tests are performed to determine the cytotoxicity and phototoxicity of pure curcumin (CR) and selected CR-containing carriers on RRC. The effect of the unloaded and CR-loaded carriers on the antiviral activity, the behavior of the extracellular virions, and the influence on viral adsorption is evaluated against coronavirus HCoV-OC43 and HSV-1 virus by using suitable microbiological assays. In accordance with the obtained experimental results, the toxicity of carriers containing CR is significantly reduced compared to pure compound and unloaded carriers. Moreover, the activity of the unloaded carriers can be increased several times by incorporating CR. The experimental results demonstrate that the variation in the properties of even one component of the structural composition can provoke the different activity of the carriers. Full article

Introduction. The rise of multidrug resistance in Gram-negative ESKAPE pathogens is a critical challenge for modern healthcare. Colistin (CT), a peptide antibiotic, remains a last-resort treatment for infections caused by these superbugs due to its potent activity against Gram-negative bacteria and the rarity of resistance. However, its clinical use is severely limited by high nephro- and neurotoxicity, low oral bioavailability, and other adverse effects. A promising strategy to improve the biopharmaceutical properties and safety profile of antibiotics is the development of biopolymer-based delivery systems, also known as nanoantibiotics. Objective. The aim of this study was to develop polyelectrolyte complexes (PECs) for the oral delivery of CT to overcome its major limitations, such as poor bioavailability and toxicity. Methods. PECs were formulated using chondroitin sulfate (CHS) and a cyanocobalamin–chitosan conjugate (CSB12). Vitamin B12 was incorporated as a targeting ligand to enhance intestinal permeability through receptor-mediated transport. The resulting complexes (CHS-CT-CSB12) were characterized for particle size, ζ-potential, encapsulation efficiency, and drug release profile under simulated gastrointestinal conditions (pH 1.6, 6.5, and 7.4). The antimicrobial activity of the encapsulated CT was evaluated in vitro against Pseudomonas aeruginosa. Results. The CHS-CT-CSB12 PECs exhibited a hydrodynamic diameter of 446 nm and a ζ-potential of +28.2 mV. The encapsulation efficiency of CT reached 100% at a drug loading of 200 µg/mg. In vitro release studies showed that approximately 70% of the drug was released within 1 h at pH 1.6 (simulating gastric conditions), while a cumulative CT release of 80% over 6 h was observed at pH 6.5 and 7.4 (simulating intestinal conditions). This release profile suggests the potential use of enteric-coated capsules or specific administration guidelines, such as taking the drug on an empty stomach with plenty of water. The antimicrobial activity of encapsulated CT against P. aeruginosa was comparable to that of the free drug, with a minimum inhibitory concentration of 1 µg/mL for both. The inclusion of vitamin B12 in the PECs significantly improved intestinal permeability, as evidenced by an apparent permeability coefficient (P_app) of 1.1 × 10⁻⁶ cm/s for CT. Discussion. The developed PECs offer several advantages over conventional CT formulations. The use of vitamin B12 as a targeting ligand enhances drug absorption across the intestinal barrier, potentially increasing oral bioavailability. In addition, the controlled release of CT in the intestinal environment reduces the risk of systemic toxicity, particularly nephro- and neurotoxicity. These findings highlight the potential of CHS-CT-CSB12 PECs as a nanotechnology-based platform for improving the delivery of CT and other challenging antibiotics. Conclusions. This study demonstrates the promising potential of CHS-CT-CSB12 PECs as an innovative oral delivery system for CT that addresses its major limitations and improves its therapeutic efficacy. Future work will focus on in vivo evaluation of the safety and efficacy of the system, as well as exploring its applicability for delivery of other antibiotics with similar challenges. Full article

pH sensitivity of chitosan allows for precise phase transitions in acidic environments, controlling swelling and shrinking, making chitosan suitable for drug delivery systems. pH transitions are modulated by the presence of cross-linkers by the functionalization of the chitosan chain. This review relays a summary of chitosan functionalization and tailoring to optimize drug release. The potential to customize chitosan for different environments and therapeutic uses introduces opportunities for drug encapsulation and release. The focus on improving drug encapsulation and sustained release in specific tissues is an advanced interpretation, reflecting the evolving role of chitosan in achieving targeted and more efficient therapeutic outcomes. This review describes strategies to improve solubility and stability and ensure the controlled release of encapsulated drugs. The discussion on optimizing factors like cross-linking density, particle size, and pH for controlled drug release introduces a deeper understanding of how to achieve specific therapeutic effects. These strategies represent a refined approach to designing chitosan-based systems, pushing the boundaries of sustained release technologies and offering new avenues for precise drug delivery profiles. Full article

In this paper, the effect of soybean isolate protein (SPI) content on the physicochemical properties and oxidative stability of chitosan–sodium tripolyphosphate (CS-STPP)-loaded fish oil capsules was investigated. The SPI/CS-STTP capsules formed after the addition of different amounts of SPI were larger in size and more homogeneous in morphology than the CS-STPP capsules, and the SPI was encapsulated on the surface of the CS matrix, altering the surface properties and morphology of the particles. The study of different CS-to-SPI blend ratios (1:0, 3:1, 2:1, 1:1, 1:2) showed that the water content of the microcapsules increased from 49.79% to 53.27–64.99%, the fish oil loading increased from 17.06% to 18.31–24.89%, and the encapsulation rate increased from 89.42% to 93.90–96.14%. In addition, the addition of SPI reduced the maximum peroxide value from 445 to 264 meq/kg oil. In the simulated in vitro digestion experiments, the addition of various amounts of SPI resulted in a significantly lower percentage of final free fatty acid (FFA) release than observed for CS-STPP capsules alone. These changes observed in the properties may be due to structural differences between CS-STPP capsules and SPI/CS-STPP capsules. All the results confirm that the obtained capsules are promising for the development of functional foods and drugs. Full article

Cryptococcus neoformans is an opportunistic fungal pathogen that is a continuous global health concern, especially for immunocompromised populations. The World Health Organization recognized C. neoformans as one of four critical fungal pathogens, thus emphasizing the need for increased research efforts and clinical resource expansion. Currently, there are no fungal vaccines available for clinical use. Exciting new findings in cryptococcal vaccine development have identified whole cell-based and subunit-based vaccinations to help mitigate health risks and make commercialization attainable. Importantly, recent work has focused on how different cryptococcal cell-wall antigens modified in these vaccine candidates allow us to manipulate their immunogenicity to produce a desired long-term protective anti-fungal immune response. In this review, we discuss the different cryptococcal cell immunogens, namely the polysaccharide capsule, glucans, chitin/chitosan, mannoproteins, and extracellular vesicles, and their role in novel cryptococcal vaccination approaches. Additionally, we examine the immunological mechanisms responsible for protection in these vaccine candidates and the similar host response-stimulation pathways induced through different immunogen exposure. Full article

Cancer and infectious diseases are two of the world’s major public health problems. Gemcitabine (GEM) is an effective chemotherapeutic agent against several types of cancer. In this study, we developed macrocapsules incorporating GEM into a chitosan matrix blended with magnetite and zeolite by ionic gelation. Physicochemical characterization was performed using HRTEM-ED, XRD, FESEM–EDS, FT-IR, TGA, encapsulation efficiency (%E.E.), and release profiles at pHs 7.4 and 5.0. Cell viability tests against A549 and H1299 cell lines, and microbiological properties against staphylococcal strains were performed. Our results revealed the successful production of hemispherical capsules with an average diameter of 1.22 mm, a rough surface, and characteristic FT-IR material interaction bands. The macrocapsules showed a high GEM encapsulation efficiency of over 86% and controlled release over 24 h. Cell viability assays revealed that similar cytotoxic effects to free GEM were achieved with a 45-fold lower GEM concentration, suggesting reduced dosing requirements and potentially fewer side effects. Additionally, the macrocapsules demonstrated potent antimicrobial activity, reducing Staphylococcus epidermidis growth by over 90%. These results highlight the macrocapsules dual role as a chemotherapeutic and antimicrobial agent, offering a promising strategy for treating lung cancer in patients at risk of infectious diseases or who are immunosuppressed. Full article

This study focuses on developing an encapsulated and dehydrated formulation of vegetative actinobacteria cells for an efficient application in sustainable agriculture, both as a fungicidal agent in crop protection and as a growth-stimulating agent in plants. Three strains of actinobacteria were used: one from a collection (Streptomyces sp.) and two natives to agricultural soil, which were identified as S3 and S6. Vegetative cells propagated in a specific liquid medium for mycelium production were encapsulated in various alginate–chitosan composites produced by extrusion. Optimal conditions for cell encapsulation were determined, and cell damage from air-drying at room temperature was evaluated. The fresh and dehydrated composites were characterized by porosity, functional groups, size and shape, and their ability to protect the immobilized vegetative cells’ viability. Actinomycetes were immobilized in capsules of 2.1–2.7 mm diameter with a sphericity index ranging from 0.058 to 0.112. Encapsulation efficiency ranged from 50% to 88%, and cell viability after drying varied between 44% and 96%, depending on the composite type, strain, and airflow. Among the three immobilized and dried strains, S3 and S6 showed greater resistance to encapsulation and drying with a 4 L·min⁻¹ airflow when immobilized in coated and core-shell composites. Encapsulation in alginate–chitosan matrices effectively protects vegetative actinobacteria cells during dehydration, maintaining their viability and functionality for agricultural applications. Full article

In this study, we used chitosan/sodium alginate hydrogel as a carrier to prepare berberine sustained-release capsule materials that can inhibit algae for a long time and safely. The preparation conditions of the material were optimized by the response surface method, and the optimized capsule material was characterized and the sustained release characteristics were analyzed to study the change of the algae inhibition effect of the material within 30 days. The results showed that the optimum preparation parameters of the material were 0.54% chitosan content, 2.46% sodium alginate content and 1.09% anhydrous calcium chloride content by response surface optimization design, which was consistent with the parameters set by each factor at the central point. The algae inhibition rate of the material under this preparation condition was 93.75 ± 1.01%, which was similar to the predicted value. The release characteristics analysis showed that the material continuously released up to 90% of berberine within 24 days, and its release characteristics were sustained release after burst release, with good sustained release effect. The results of material characterization showed that chitosan/sodium alginate hydrogel could effectively load berberine and was beneficial to the loading and release of berberine. The results of algae inhibition experiments showed that low concentration materials could control the outbreak of cyanobacterial blooms in a short time, while under high concentration conditions, the materials could inhibit Microcystis aeruginosa efficiently and for a long time. Full article

The application of continuous fermentation with immobilized cells in brewing is a challenge because of problems with carrier selection and reactor design, which have economic impacts on the beer produced. Moreover, immobilization alters yeast physiology, which significantly affects beer flavor and aroma. Therefore, the aim of this study was to investigate the feasibility of a continuous fermentation system, consisting of a packed bed column bioreactor, containing lager brewing yeast, immobilized in alginate–chitosan microcapsules with a liquid core, in the primary beer fermentation. The results showed that the system entered in a stationary mode on the 3rd day and worked stably in this mode for 6 days. The “green” beer was taken at every 24 h at the output of the reactor and used for secondary fermentation with the yeast cells leaked from the capsules during the primary fermentation. The extract consumption, ethanol production, and pH change during primary and secondary fermentation were investigated. Some of the secondary yeast metabolites such as vicinal diketones, higher alcohols, esters, and aldehydes in “green” and final beers were determined and it was found that the flavor profile of the final beer was comparable to two industrially produced Bulgarian beers. Full article

The aim of this study was to obtain drinking yogurts enriched with ACTICOA cocoa powder (ACTICOA), its extract (EACTICOA) and pure phenolics, as well as their inclusion complexes with cyclodextrins and alginate–chitosan (A-Ch) capsules, and to evaluate the effects of these additives on the viability of lactic acid bacteria (LAB) and antioxidant properties of fresh yogurts and yogurts stored for 14 days at 4 °C. The application of cocoa phenolic compounds in free form and in the form of EACTICOA to yogurts resulted in the greatest increase in the concentration of phenolic compounds and a significant improvement in the antioxidant properties of the fortified products. The highest TPC was found in yogurts enriched with free quercetin (107.98 mg CE/g). Yogurt fortified with free gallic acid showed the highest ability to neutralize free radicals (EC50 = 2.74 mg/mg DPPH, EC50 = 5.40 mg/mg ABTS) and reduce ferric ions (183.48 µM Trolox/g). The enrichment of yogurts with the tested phenolic compounds preparations, especially in the form of encapsulates, did not affect the viability of LAB during storage. Full article