Search Results (29)

Vibrio harveyi is an important pathogen causing enteritis in hybrid groupers. However, its effects on the intestinal microbiota and the regulatory effects of oligochitosan on Vibrio-infected groupers are unclear. In this study, we investigated the effects of infection with V. harveyi and oligochitosan administration on the growth performance, immune responses, and intestinal transcriptome profiles of hybrid groupers during a 60-day rearing period. Growth parameters were reduced in Vibrio-infected groupers, while oligochitosan improved the body weight. Biochemical analysis showed reduced antioxidant enzyme activity and increased lipid peroxidation in Vibrio-infected groupers, which were consequently improved by oligochitosan. Transcriptome analysis was used to identify differentially expressed genes in the disease-related and immune system pathways that significantly accumulated in the treatment groups. An evaluation of the immune response showed a significant down-regulation of proinflammatory cytokines, antioxidant genes, and tight-junction proteins in Vibrio-infected groupers, which was partially restored by oligochitosan. Additionally, intestinal apoptosis, indicated by TUNEL signaling, was observed to significantly increase in Vibrio-infected groupers and was subsequently alleviated by oligochitosan supplementation. These results demonstrate the detrimental effects of V. harveyi infection on the growth and immune function of hybrid groupers and the potential of oligochitosan to attenuate these effects. Full article

Chitosan is a natural polymer with numerous biomedical applications. The cellular activity of chitosan has been studied in various types of cancer, including melanoma, and indicates that these molecules can open new perspectives on antiproliferative action and anticancer therapy. This study analyzes how different chitosan conformations, such as α-chitosan (CH) or β-oligochitosan (CO), with various degrees of deacetylation (DDA) and molar mass (MM), both in different concentrations and in CH–CO mixtures, influence the cellular processes of SK-MEL-28 melanocytes, to estimate the reactivity of these cells to the applied treatments. The in vitro evaluation was carried out, aiming at the cellular metabolism (MTT assay), cellular morphology, and chitinase-like glycoprotein YKL-40 expression. The in vitro effect of the CH–CO mixture application on melanocytes is obvious at low concentrations of α-chitosan/β-oligochitosan (1:2 ratio), with the cell’s response supporting the hypothesis that β-oligo-chitosan amplifies the effect. This oligochitosan mixture, favored by the β conformation and its small size, penetrates faster into the cells, being more reactive when interacting with some cellular components. Morphological effects expressed by the loss of cell adhesion and the depletion of YKL-40 synthesis are significant responses of melanocytes. β-oligochitosan (1.5 kDa) induces an extension of cytophysiological effects and limits the cell viability compared to α-chitosan (400–900 kDa). Statistical analysis using multivariate techniques showed differences between the CH samples and CH–CO mixtures. Full article

Pseudostellaria heterophylla (or Taizishen in Chinese), a medicinal, edible, and ornamental Chinese herb, is seriously affected by leaf spot disease (LSD). Oligochitosan is a natural agricultural antibiotic that is produced via the degradation of chitosan, which is deacetylated from chitin; pyraclostrobin is a broad-spectrum and efficient strobilurin fungicide. In this work, the ability of pyraclostrobin, oligochitosan, and their formula to manage P. heterophylla leaf spot disease and their role in its resistance, leaf photosynthesis, agronomic plant traits, root growth, and root quality were studied. The results show that the joint application of oligochitosan and low-dosage pyraclostrobin could control LSD more efficiently, with control effects of 85.75–87.49% compared to high-dosage pyraclostrobin or oligochitosan alone. Concurrently, the application of this formula could more effectively improve the resistance, leaf photosynthesis, agronomic plant traits, root yield, and medicinal quality of P. heterophylla, as well as reduce the application of pyraclostrobin. This finding suggests that 30% pyraclostrobin suspension concentrate (SC) 1500-time + 5% oligosaccharin aqueous solutions (AS) 500-time diluent can be recommended for use as a feasible formula to manage LSD and reduce the application of chemical pesticides. Full article

The paper presents the results of the synthesis, a detailed kinetics study, and an investigation of the biological activity of silver nanoparticles (AgNPs) in aqueous solutions of N-reacetylated oligochitosan hydrochloride. UV–visible spectrophotometry and dynamic light scattering were employed to control silver ion reduction. The process was observed to follow a pseudo-first-order law. Transmission and scanning electron microscopy demonstrated that AgNPs ranging in size from 10 to 25 nm formed aggregates measuring 60 to 90 nm, with the aggregate surface coated by a 2–4 nm chitosan shell. X-ray microanalysis and powder X-ray diffractometry were used to study the phase composition, identifying two crystalline phases, nanocrystalline silver and AgCl, present in the dispersions. The antibacterial effect was assessed using the serial dilution method for dispersions with varying degrees of Ag⁺ conversion. Nanodispersions exhibited significant activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, and Staphylococcus aureus. Interestingly, the activity did not appear to be heavily influenced by the presence of the AgCl phase or the concentration of Ag⁺ ions. These synthesized dispersions hold promise for the development of materials tailored for biomedical applications. Full article

Glycation by transglutaminase (TGase)-type could effectively improve the structure and functional properties of proteins. However, the influence on intestinal inflammation or the underlying mechanisms has not been investigated. The goal of this research was to compare the bioactivities between glycated casein generated from the TGase-catalyzed reaction and oligochitosan as well as casein using a mouse model of dextran sulfate sodium (DSS)-induced intestinal inflammation to examine the protective effects and the underlying mechanism of glycated casein on intestinal inflammation. Eight groups of C57BL/6 mice were randomly assigned in this study: Control group: standard diet for 35 days; Model group: standard diet for 28 days and then colitis induction; Pretreated groups: different levels (200, 400, 800 mg/kg BW) of casein or glycated casein for 28 days before colitis induction. The mice were drinking water containing a 3% DSS solution for seven days of mice to cause colitis. The results indicated that glycated casein and casein at 200–800 mg/kg BW all relieved DSS-induced weight loss, reduced disease activity index (DAI) score, alleviated colon length shortening, weakened the destruction of colonic mucosal structure, decreased serum LPS, and MPO, IL-1β, IL-6 and TNF-α levels in serum and colon, as well as regulated the expression of proteins involved in the TLR4/NF-κB signaling pathway in a concentration-dependent manner. Glycated caseinate showed a better protective effect against DSS-induced colitis than casein, highlighting that the TGase-type glycation of proteins as a potential functional food ingredient might be a helpful method for gut health. Full article

Edible crayfish are an object of local fishing and artificial breeding in many countries. This industry is very promising in terms of production of healthy foods and byproducts, such as biologically active polyaminosaccharide—chitosan and its derivatives. However, crayfishing is far from being at the level at which it could be. This laboratory scale protocol describes a walkway from crayfish Actacus leptodactylus to chitin, chitosan, and oligochitosan hydrochloride, with the main emphasis on the way of getting rid of the impurities (residual heavy metals, proteins and other residues) commonly present in commercial chitosan and its derivatives, as well as the characterization of the products by means of inductively-coupled plasma mass spectrometry (ICP-MS), energy-dispersive X-ray spectroscopy (EDXS), protein and elemental analysis, proton magnetic resonance spectroscopy (¹H NMR), and chromatography methods. The protocol includes the preparation of crude shell waste; the extraction of proteins from crude shell waste and preparation of deproteinated shell waste, demineralization and decolorization of the deproteinated crayfish shell waste, deacetylation of chitin, and depolymerization of chitosan. EDXS shows the presence of Al and Si residues in chitin is found when the deproteination of crayfish waste is carried out in an alumosilicate glass vessel. In contrast, these residues are absent when deproteination is carried out in the borosilicate glass flask. Analytical data show that the content of residues in chitosan and oligochitosan hydrochloride meets pharmaceutical requirements. The study demonstrates crayfish waste a promising for the purification of chitosan, for the preparation of pharmaceutical grade oligochitosan hydrochloride, and can improve commercialization of crayfishes. Full article

Uncontrolled and sustained inflammation disrupts the wound-healing process and produces excessive reactive oxygen species, resulting in chronic or impaired wound closure. Natural antioxidants such as plant-based extracts and natural polysaccharides have a long history in wound care. However, they are hard to apply to wound beds due to high levels of exudate or anatomical sites to which securing a dressing is difficult. Therefore, we developed a complex coacervate-based drug carrier with underwater adhesive properties that circumvents these challenges by enabling wet adhesion and controlling inflammatory responses. This resulted in significantly accelerated wound healing through balancing the pro- and anti-inflammatory responses in macrophages. In brief, we designed a complex coacervate-based drug carrier (ADC) comprising oligochitosan and inositol hexaphosphate to entrap and release antioxidant proanthocyanins (PA) in a sustained way. The results from in vitro experiments demonstrated that ADC is able to reduce LPS-stimulated pro-inflammatory responses in macrophages. The ability of ADC to reduce LPS-stimulated pro-inflammatory responses in macrophages is even more promising when ADC is encapsulated with PA (ADC-PA). Our results indicate that ADC-PA is able to polarize macrophages into an M2 tissue-healing phenotype via up-regulation of anti-inflammatory and resolution of inflammatory responses. Treatment with ADC-PA around the wound beds fine-tunes the balance between the numbers of inducible nitric oxide synthase-positive (iNOS+) and mannose receptor-negative (CD206-) M1 and iNOS-CD206+ M2 macrophages in the wound microenvironment compared to controls. Achieving such a balance between the numbers of iNOS+CD206- M1 and iNOS-CD206+ M2 macrophages in the wound microenvironment has led to significantly improved wound closure in mouse models of diabetes, which exhibit severe impairments in wound healing. Together, our results demonstrate for the first time the use of a complex coacervate-based drug delivery system to promote timely resolution of the inflammatory responses for diabetic wound healing by fine-tuning the functions of macrophages. Full article

In most wine-growing countries of the world the interest for organic viticulture and eco-friendly grape production processes increased significantly in the last decade. Organic viticulture is currently dependent on the availability of Cu and S compounds, but their massive use over time has led to negative effects on environment health. Consequently, the purpose of this study was to evaluate the effectiveness of alternative and sustainable treatments against powdery mildew, gray mold and sour rot under the field conditions on Nero d’Avola and Inzolia Sicilian cultivars. In detail, the efficacy of COS-OGA, composed by a complex of oligochitosans and oligopectates, and its effects in combination with arbuscular mycorrhizal fungi (AMF) were evaluated to reduce airborne disease infections of grape. COS-OGA combined with AMF induced a significant reduction in powdery mildew severity both on Nero d’Avola and Inzolia with a mean percentage decrease of about 15% and 33%, respectively. Moreover, COS-OGA alone and combined with AMF gave a good protection against gray mold and sour rot with results similar to the Cu–S complex (performance in disease reduction ranging from 65 to 100%) on tested cultivars. Similarly, the COS-OGA and AMF integration provided good performances in enhancing average yield and did not negatively impact quality and microbial communities of wine grape. Overall, COS-OGA alone and in combination could be proposed as a valid and safer option for the sustainable management of the main grapevine pathogens in organic agroecosystems. Full article

(1) Background: Thymus vulgaris L. (thyme) essential oil (TEO) has gained much attention because of its long history of medicinal usage. However, the lack of precise chemical profiling of the TEO and methods to optimize the bioactivity and delivery of its constituents has hampered its research on quality control and biological function; (2) Methods: The current study aimed to analyze the TEO’s chemical composition using the GC-MS method and identify its key components. Another objective of this work is to study the impact of the protective layer of amphiphilic oligochitosan (AOC) on the physicochemical stability and transdermal potentials of TEO multilayer nanoemulsions formulated by the incorporation of TEO, Tween80, lecithin (Lec), and AOC; (3) Results: The AOC protective layer significantly improved the stability of TEO-based NEs as revealed by the constancy of their physicochemical properties (particle size and zeta potential) during storage for a week. Excessive fine-tuning of thyme extract NEs and the AOC protective layer’s persistent positive charge have been contributed to the thyme extract’s improved anti-inflammatory, transdermal, and anti-melanoma potentials; (4) Conclusions: the AOC-coated NEs could offer novel multifunctional nanoplatforms for effective transdermal delivery of lipophilic bioactive materials. Full article

Fungi constitute the largest number of plant pathogens and are responsible for a range of serious plant diseases. Phaeomoniella chlamydospora (P. chlamydospora) and Phaeoacremonium aleophilum (P. aleophilum) are the main fungal pathogens causing esca disease in grapevines. On the other hand, there are beneficial microorganisms such as Trichoderma spp., which are able to control the growth of many phytopathogens. In the present study, innovative, eco-friendly hybrid nanomaterials were created by electrospinning PLLA, followed by the formation of a film of chitosan/Trichoderma asperellum (T. asperellum) spores on the fibers. The polymer carrier used in this study plays an active role in ensuring the viability of the biological agent during storage and, when placed in contact with moisture, ensures the agent’s normal development. Oligochitosan, as well as low molecular weight and high molecular weight chitosan, were used. The effects of chitosan molecular weight on the dynamic viscosity of chitosan solutions, film formation, mechanical properties, spore incorporation and growth were studied. The morphology of the prepared nanomaterials, and the presence of a film based on the formation of chitosan/T. asperellum spores on the PLLA fibers, were examined using scanning electron microscopy (SEM). The surface chemical compositions of the fibrous materials were studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The mechanical properties of the obtained materials were also tested. The microbiological screening that was performed revealed that the eco-friendly hybrid nanomaterials incorporated with the beneficial microorganism, T. asperellum, to hamper the growth of the pathogenic P. chlamydospora and P. aleophilum fungi. The suppression rate depended on the viscosity of the chitosan solution used for the film formation. The use of oligochitosan resulted in the most effective infection of the material with T. asperellum spores. The environmentally friendly hybrid nanomaterials obtained in this study—in which the bioagent was embedded—are promising bioactive dressings for protecting grapevines against esca disease. Full article

Perilla (Perilla frutescens) belongs to the Lamiaceae family, is used as a spicy culinary herb leafy vegetable as well as medicinal and ornamental plant. However, little is known about protocols for baby leaf perilla production. Native chitosan is a well-known biostimulant used in crop plant production. Nevertheless, the influence of water-soluble chitosan oligosaccharide lactate (ChOL) on plant growth and bioactive compounds content remains unknown. The present pot experiment determines the effects of ChOL (0, 50 and 100 mg/L) on growth and selected biochemical characteristics of baby leaf red perilla. Compared to the untreated plants, ChOL application at 50 and 100 mg/L increased plant height (by 14.6% and 13.2%), the fresh weight of the above-ground part of plants (by 17.1% and 26.7%), leaves (by 21.8% and 35.5%) and roots (by 52.2%). The levels of total reducing sugars, polyphenolics, flavonoids and anthocyanins in perilla leaves were significantly higher in all plants treated with ChOL at all tested concentrations. This was confirmed by macromolecules (FT-IR) studies showing higher band intensity for key functional groups in leaf samples. The application of ChOL also enhanced the antioxidant activity by using DPPH, ABTS and O₂⁻ radical scavenging activity assays. Based on the research, results suggested that ChOL may be used an effective plant biostimulant for high quality production of baby leaf red perilla. Full article

In this study, milk protein casein was glycated by oligochitosan through the catalysis of transglutaminase (TGase) and then hydrolyzed by trypsin. The obtained glycated casein hydrolysates (GCNH) were assessed for their anti-inflammatory activities, using the lipopolysaccharide (LPS)-stimulated rat intestinal epithelial cells (IEC-6) as cell models and the casein hydrolysates (CNH) without TGase catalysis as controls. The results showed that GCNH had oligochitosan incorporation and thus possessed a glucosamine content of 5.74 g/kg protein. In general, GCNH at dose levels of 25–100 μg/mL could elevate IEC-6 cell growth, and at dose levels of 25–50 μg/mL, they were also able to alleviate the LPS-induced cytotoxicity by increasing cell viability efficiently. Although LPS caused clear inflammation in the LPS-stimulated cells, GCNH were capable of reducing the secretion of three pro-inflammatory mediators including interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α, or promoting the secretion of two anti-inflammatory mediators like IL-10 and transforming growth factor-β, demonstrating their anti-inflammatory activities to the stimulated cells. Moreover, GCNH also could down-regulate the expression of three inflammation-related proteins including TLR4, p-p38, and p-p65 in the stimulated cells, and thus possessed a capacity to suppress the phosphorylation of p38 and p65 proteins as well as to inactivate the NF-κB and MAPK signaling pathways. Additionally, a higher GCNH dose level consistently led to higher anti-inflammatory effect in the cells, while GCNH were always more potent than CNH at performing anti-inflammatory function targets. It is thus suggested that the TGase-catalyzed casein oligochitosan-glycation could enhance the anti-inflammatory activities of casein hydrolysates efficiently. TGase-catalyzed protein glycation thus might enhance the healthcare function of protein ingredients in the body. Full article

Animal chitosan (Chit-A) is gaining more acceptance in daily activities. It is used in a range of products from food supplements for weight loss to even raw materials for producing nanoparticles and hydrogel drug carriers; however, it has low antioxidant activity. Fungal oligochitosan (OChit-F) was identified as a potential substitute for Chit-A. Cunninghamella elegans is a fungus found in the Brazilian savanna (Caatinga) that produces OligoChit-F, which is a relatively poorly studied compound. In this study, 4 kDa OChit-F with a 76% deacetylation degree was extracted from C. elegans. OChit-F showed antioxidant activity similar to that of Chit-A in only one in vitro test (copper chelation) but exhibited higher activity than that of Chit-A in three other tests (reducing power, hydroxyl radical scavenging, and iron chelation). These results indicate that OChit-F is a better antioxidant than Chit-A. In addition, Chit-A significantly increased the formation of calcium oxalate crystals in vitro, particularly those of the monohydrate (COM) type; however, OChit-F had no effect on this process in vitro. In summary, OChit-F had higher antioxidant activity than Chit-A and did not induce the formation of CaOx crystals. Thus, OChit-F can be used as a Chit-A substitute in applications affected by oxidative stress. Full article

Curcumin nanosuspensions (Cur-NSs), chitosan-coated Cur-NSs (CS-Cur-NSs), and oligochitosan-coated Cur-NSs (OCS-Cur-NSs) were prepared by using an ultrasonic homogenization technique. The mean particle size of Cur-NSs was 210.9 nm and significantly (p < 0.05) increased to 368.8 nm by CS coating and decreased to 172.8 nm by OCS coating. Encapsulation efficiencies of Cur-NSs, CS-Cur-NSs, and OCS-Cur-NSs were 80.6%, 91.4%, and 88.5%, respectively. The mucin adsorption of Cur-NSs was steeply increased about 3–4 times by CS and OCS coating. Morphological changes of these NSs were studied using circular dichroism spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, and transmission electron microscopy (TEM). Thus, CS-Cur-NSs and OCS-Cur-NSs showed great potential as mucoadhesive nano-carriers for the efficient delivery of water insoluble compounds like curcumin to the gastrointestinal system. Full article

Chitosan derivatives with a low molecular weight can enhance plant growth and improve tolerance to various stresses. Hardy ferns form a group of attractive garden perennials with an unknown response to plant biostimulants. Cold winter temperature limits the growth and reduces the decorative value of evergreen fern species. This study was carried out to explore the effects of chitosan oligosaccharide lactate (COL) with Mn = 5000 on the growth of the evergreen fern Cyrtomium fortunei var. clivicola. COL sprayed at 50 and 100 mg/L significantly increased the height of the plant and fresh weight of the above-ground and underground parts of C. fortunei var. clivicola compared to control plants. Moreover, ferns sprayed with 50 and 100 mg/L COL also had higher leaf total chlorophyll contents and value score. These results indicate that COL improved C. fortunei var. clivicola growth and overwintering and may be used for high-quality hardy ferns’ production. Full article