While largely depending on other microorganisms for nitrogen (N) mineralization, arbuscular mycorrhizal fungi (AMF) can transfer N from organic sources to their host plants. Here, we compared N acquisition by the AMF hyphae from chitin and protein sources and assessed the effects of microbial interactions in the hyphosphere. We employed in vitro compartmented microcosms, each containing three distinct hyphosphere compartments amended with different N sources (protein, chitin, or ammonium chloride), one of which was enriched with 15N isotope. All hyphosphere compartments were supplied with Paenibacillus bacteria, with or without the protist Polysphondylium pallidum. We measured the effect of these model microbiomes on the efficiency of 15N transfer to roots via the AMF hyphae. We found that the hyphae efficiently took up N from ammonium chloride, competing strongly with bacteria and protists. Mobilization of 15N from chitin and protein was facilitated by bacteria and protists, respectively. Notably, AMF priming significantly affected the abundance of bacteria and protists in hyphosphere compartments and promoted mineralization of protein N by protists. Subsequently, this N was transferred into roots. Our results provide the first unequivocal evidence that roots can acquire N from proteins present in the AMF hyphosphere and that protists may play a crucial role in protein N mineralization.

• Klíčová slova
• arbuscular mycorrhizal fungus, hyphosphere, multitrophic interactions, organic nitrogen, quantitative real‐time PCR, stable isotopes, temporal dynamics,
• MeSH
• chitin metabolismus   MeSH
• dusík * metabolismus   MeSH
• Eukaryota * metabolismus   MeSH
• hyfy metabolismus   MeSH
• izotopy dusíku MeSH
• kořeny rostlin mikrobiologie   metabolismus   MeSH
• mykorhiza * metabolismus   MeSH
• rostlinné proteiny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chitin MeSH
• dusík * MeSH
• izotopy dusíku MeSH
• rostlinné proteiny MeSH

The study introduces a novel method for fabricating crosslinked chitosan/polypyrrole (PPy) composite nanofibers with covalently anchored PPy. Crosslinking is achieved already during electrospinning by using dialdehyde cellulose (DAC) as a dual-functioning reagent able to simultaneously crosslink chitosan nanofibers and covalently tether PPy nanoparticles by a newly discovered aldol condensation reaction. The presented method eliminates the need for postprocessing steps. It reduces the environmental impact by avoiding toxic organic chemicals while preventing PPy leaching and improving prepared composite nanofibers' mechanical and biological properties. A direct comparison to neat chitosan nanofibres was performed to demonstrate the superiority of prepared composites. The resulting crosslinked CHIT_DAC_PPy composite nanofibers have increased tensile strength, improved stability at low pH, conductivity up to 11 mS/cm, and higher swelling compared to neat CHIT nanofibers. They also possess significantly enhanced antibacterial activity against gram-positive S. aureus, higher antioxidant activity, increased immunomodulatory effects, and substantially higher acceleration of wound healing in vitro. CHIT_DAC_PPy nanofibrous composite thus shows significant potential for fabricating advanced wound dressings.

• Klíčová slova
• Chitosan, Nanofibers, Polypyrrole,
• MeSH
• antibakteriální látky * farmakologie   chemie   MeSH
• antioxidancia * farmakologie   chemie   MeSH
• celulosa * chemie   analogy a deriváty   farmakologie   MeSH
• chitosan * chemie   farmakologie   MeSH
• hojení ran účinky léků   MeSH
• imunologické faktory * farmakologie   chemie   MeSH
• mikrobiální testy citlivosti MeSH
• myši MeSH
• nanovlákna * chemie   ultrastruktura   MeSH
• pevnost v tahu MeSH
• polymery * chemie   farmakologie   MeSH
• pyrroly * chemie   farmakologie   MeSH
• Staphylococcus aureus účinky léků   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky * MeSH
• antioxidancia * MeSH
• celulosa * MeSH
• chitosan * MeSH
• imunologické faktory * MeSH
• polymery * MeSH
• polypyrrole MeSH Prohlížeč
• pyrroly * MeSH

Polypyrrole (PPy) composites, despite their conductivity and bioactivity, are prone to degradation (e.g., exfoliation or delamination) due to the lack of chemical bonds between PPy and the matrix. Rather than suppressing this degradation through laborious methods involving toxic organic linkers or custom pyrrole derivatives to achieve covalently bonded PPy composites, this study introduces a novel polysaccharide-based approach. This method uses dialdehyde polysaccharides (DAPs) to conjugate PPy to chitosan nanofibers (CHITs) covalently. DAPs stabilize CHITs through Schiff base chemistry and then conjugate pyrrole via aldol condensation. During subsequent polymerization, the conjugated pyrrole is incorporated into the PPy layer formed around the CHITs, covalently linking both polymers. The resulting composites exhibit good conductivity and cytocompatibility, making them promising for biomedical applications and tissue engineering. Moreover, this method is not limited to chitosan but can be extended to other amine-containing substrates.

• Klíčová slova
• Chitosan nanofibers, Conductive composite, Dialdehyde polysaccharides, Polypyrrole,
• MeSH
• aldehydy chemie   MeSH
• biokompatibilní materiály chemie   MeSH
• chitosan * chemie   MeSH
• elektrická vodivost * MeSH
• nanovlákna * chemie   MeSH
• polymery * chemie   MeSH
• polysacharidy * chemie   MeSH
• pyrroly * chemie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aldehydy MeSH
• biokompatibilní materiály MeSH
• chitosan * MeSH
• polymery * MeSH
• polypyrrole MeSH Prohlížeč
• polysacharidy * MeSH
• pyrroly * MeSH

Regenerating skin tissue remains a major challenge in medical science, especially due to the risk of scarring and prolonged healing, which becomes even more complicated in people with diabetes. Recent advancements have led to the creation of therapeutic dressings incorporating drug-delivery systems to tackle these issues. Exosomes (Exos) derived from mesenchymal stem cells (MSCs) have gained significant attention for mediating therapy without directly using cells, thanks to their natural anti-inflammatory and tissue repair properties mirroring those of MSCs. In this study, an advanced wound dressing combines chitosan (CS) and polyethylene glycol (PEG) hydrogel with adipose MSCs-derived Exos (ADMSCs-Exos). This composite, formed using a straightforward blending technique, is engineered to improve the healing process of severe skin injuries by steadily releasing Exos as the hydrogel degrades. The in vitro studies demonstrate that this hydrogel-exosome dressing greatly enhances endothelial cell migration, reduces oxidative stress, and promotes angiogenesis, crucial for effective wound healing. Additionally, real time-polymerase chain reaction (RT-PCR) analysis revealed significant upregulation of key genes involved in these processes, supporting the therapeutic potential of the hydrogel-Exo combination. These findings emphasize the potential of this hydrogel-Exos combination as an innovative and promising solution for advanced wound care.

• Klíčová slova
• angiogenesis, cell migration, chitosan‐polyethylene glycol hydrogel, mesenchymal stem cells derived exosomes, wound healing,
• MeSH
• chitosan * chemie   farmakologie   MeSH
• endoteliální buňky pupečníkové žíly (lidské) metabolismus   MeSH
• exozómy * metabolismus   chemie   MeSH
• hojení ran * účinky léků   MeSH
• hydrogely * chemie   farmakologie   MeSH
• lidé MeSH
• mezenchymální kmenové buňky * metabolismus   cytologie   MeSH
• pohyb buněk účinky léků   MeSH
• polyethylenglykoly * chemie   farmakologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chitosan * MeSH
• hydrogely * MeSH
• polyethylenglykoly * MeSH

The aim of this study is to investigate the effects of multilayer nano-/mini- furcellaran/chitosan emulsions with oregano essential oil and bioactive peptides (RW4 and LL37) on nutritional quality, oxidation and consumer perception of pork loins stored at 4 °C and - 20 °C for 18 days and six months, respectively. The triple-layer emulsions were applied on pork loins via the electrospraying method at 20 kV. The multilayer mini-/nano-emulsions significantly inhibited lipid and protein oxidation during refrigerated and freezer storage, proving their antioxidant activity. In addition, the coatings did not negatively affect the color attributes or texture profile of pork loins either both storage conditions. Furthermore, the application of coatings had no influence on the proximate or fatty acid composition of pork loin during refrigerated storage. Therefore, this study allows to show that the developed triple-layer emulsions with oregano essential oil applied through electrospraying improved the quality and physicochemical properties of pork loins, proving potential for fresh meat preservation.

• Klíčová slova
• Chitosan, Furcellaran, Multilayer emulsions, Oregano, Oxidation, Physicochemical properties, Pork loin,
• MeSH
• antioxidancia chemie   farmakologie   MeSH
• chitosan * chemie   MeSH
• chování spotřebitelů * MeSH
• dobromysl (rod) * chemie   MeSH
• emulze chemie   MeSH
• konzervace potravin metody   MeSH
• kvalita jídla MeSH
• lidé MeSH
• oleje prchavé * chemie   farmakologie   MeSH
• oleje rostlin * chemie   MeSH
• oxidace-redukce MeSH
• prasata MeSH
• skladování potravin MeSH
• vepřové maso MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antioxidancia MeSH
• chitosan * MeSH
• emulze MeSH
• oleje prchavé * MeSH
• oleje rostlin * MeSH

Chitosan is a widely used linear biopolymer composed mainly of glucosamine and to a lesser extent of N-acetylglucosamine units. Many biological activities of chitosan are attributed to its shorter oligomeric chains, which consist of chitosan prepared either by enzyme activity (lysozyme, bacterial chitinase) or chemically by acid-catalyzed hydrolysis (e.g. in the stomach). However, these processes always result in a mixture of shorter chitooligosaccharides with varying degrees of acetylation whereas for relevant results of biological studies it is necessary to work with a precisely defined material. In this review, we provide an overview and comparison of analytical methods leading to the determination of the degree of polymerization (DP), the degree of acetylation (DA), the fraction of acetylation (FA) and the acetylation patterns (PA) of chitooligosaccharide chains and of the current state of knowledge on chitooligosaccharide separation. This review aims to present the most promising routes to well-defined low molecular weight chitosan with low dispersity.

• Klíčová slova
• Acetylation pattern, Analysis, Chitooligosacharides, Chitosan, Separation,
• MeSH
• acetylace MeSH
• chitosan * chemie   MeSH
• oligosacharidy * chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• chitosan * MeSH
• oligochitosan MeSH Prohlížeč
• oligosacharidy * MeSH

This study introduces a novel, sustainable method for synthesizing sub-5 nm palladium nanoparticles (PdNPs) and covalently binding them to chitosan nanofibers (CHITs) using fully oxidized dialdehyde cellulose (DAC). Notably, the DAC acts not only as a reducing and stabilizing agent for PdNPs, but also as a linker for their rapid and spontaneous covalent attachment to CHITs via Schiff base chemistry. This unique approach yields PdNPs with a narrow size distribution (4.7 ± 0.4 nm) and enables the preparation of a stable nanofibrous composite with excellent catalytic efficiency for 4-nitrophenol reduction (TOFPdNPs = 75.2 min-1, kPdNPs = 1.34 min-1; TOFPdNPs-CHIT = 1.18 min-1). The composite's high reusability, attributed to strong covalent binding, marks a significant improvement over traditional PdNPs composites that rely on weak interactions. This is demonstrated on a model of a catalytic device, reflecting industrial applications.

• Klíčová slova
• Chitosan nanofibers, Dialdehyde cellulose, Nanocomposite catalyst, Palladium nanoparticles,
• MeSH
• celulosa * chemie   analogy a deriváty   MeSH
• chitosan * chemie   MeSH
• katalýza MeSH
• kovové nanočástice * chemie   MeSH
• nanovlákna * chemie   ultrastruktura   MeSH
• nitrofenoly chemie   MeSH
• oxidace-redukce MeSH
• palladium * chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 2,3-dialdehydocellulose MeSH Prohlížeč
• 4-nitrophenol MeSH Prohlížeč
• celulosa * MeSH
• chitosan * MeSH
• nitrofenoly MeSH
• palladium * MeSH

Accumulation of environmental chitin in the lungs can lead to pulmonary fibrosis, characterized by inflammatory infiltration and fibrosis in acidic chitinase (Chia)-deficient mice. Transgenic expression of Chia in these mice ameliorated the symptoms, indicating the potential of enzyme supplementation as a promising therapeutic strategy for related lung diseases. This study focuses on utilizing hyperactivated human Chia, which exhibits low activity. We achieved significant activation of human Chia by incorporating nine amino acids derived from the crab-eating monkey (Macaca fascicularis) Chia, known for its robust chitin-degrading activity. The modified human Chia retained high activity across a broad pH spectrum and exhibited enhanced thermal stability. The amino acid substitutions associated with hyperactivation of human Chia activity occurred species specifically in monkey Chia. This discovery highlights the potential of hyperactivated Chia in treating pulmonary diseases resulting from chitin accumulation in human lungs.

• Klíčová slova
• acidic chitinase (Chia), amino acid substitutions, chitin, enzyme engineering, evolution, exon swapping, hyperactivation, primate lineage, treating pulmonary diseases,
• MeSH
• chitin metabolismus   MeSH
• chitinasy * genetika   metabolismus   chemie   MeSH
• koncentrace vodíkových iontů MeSH
• lidé MeSH
• myši MeSH
• stabilita enzymů MeSH
• substituce aminokyselin MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CHIA protein, human MeSH Prohlížeč
• chitin MeSH
• chitinasy * MeSH

Biomaterial-associated infections pose severe challenges in modern medicine. Previously, we reported that polyanionic DNA surface coatings repel bacterial adhesion and support osteoblast-like cell attachment in monoculture experiments, candidate for orthopaedic implant coatings. However, monocultures lack the influence of bacteria or bacterial toxins on osteoblast-like cell adhesion to biomaterial surfaces. In this study, co-culture of staphylococcus (S. epidermidis and S. aureus) and SaOS-2 osteosarcoma cells was studied on chitosan-DNA polyelectrolyte multilayer coated glass based on the concept of `the race for the surface`. Staphylococcus was first deposited onto the surface in a microfluidic chamber to mimic peri-operative contamination, and subsequently, SaOS-2 cells were seeded. Both staphylococcus and SaOS-2 cells were cultured together on the surfaces for 24 h under flow. The presence of S. epidermidis decreased SaOS-2 cell number on all surfaces after 24 h. However, the cells that adhered spread equally well in the presence of low virulent S. epidermidis. However, highly virulent S. aureus induced cell death of all adherent SaOS-2 cells on chitosan-DNA multilayer coated glass, a worse outcome than on uncoated glass. The outcome of our co-culture study highlights the limitations of monoculture models. It demonstrates the need for in vitro co-culture assays to meaningfully bridge the gap in lab testing of biomaterials and their clinical evaluations where bacterial infection can occur. The relative failure of cell-adhesive and bacteria-repelling DNA coatings in co-cultures also suggests the need to incorporate bactericidal in addition to non-adhesive functions to protect competitive cell spreading over a long period.

• Klíčová slova
• Biofilms, Biomaterial-associated infections, Co-culture, Coatings, DNA polyelectrolyte, Flow, Multilayer, Osteoblasts, Pathogens, Race for the surface, Staphylococcus,
• MeSH
• bakteriální adheze účinky léků   MeSH
• biokompatibilní potahované materiály chemie   farmakologie   MeSH
• buněčná adheze účinky léků   MeSH
• chitosan chemie   farmakologie   MeSH
• DNA * chemie   MeSH
• kokultivační techniky MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• osteoblasty * účinky léků   cytologie   MeSH
• polyelektrolyty chemie   farmakologie   MeSH
• povrchové vlastnosti * MeSH
• Staphylococcus aureus * účinky léků   MeSH
• Staphylococcus epidermidis * účinky léků   fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biokompatibilní potahované materiály MeSH
• chitosan MeSH
• DNA * MeSH
• polyelektrolyty MeSH

Although angiosperm plants generally react to immunity elicitors like chitin or chitosan by the cell wall callose deposition, this response in particular cell types, especially upon chitosan treatment, is not fully understood. Here we show that the growing root hairs (RHs) of Arabidopsis can respond to a mild (0.001%) chitosan treatment by the callose deposition and by a deceleration of the RH growth. We demonstrate that the glucan synthase-like 5/PMR4 is vital for chitosan-induced callose deposition but not for RH growth inhibition. Upon the higher chitosan concentration (0.01%) treatment, RHs do not deposit callose, while growth inhibition is prominent. To understand the molecular and cellular mechanisms underpinning the responses to two chitosan treatments, we analysed early Ca2+ and defence-related signalling, gene expression, cell wall and RH cellular endomembrane modifications. Chitosan-induced callose deposition is also present in the several other plant species, including functionally analogous and evolutionarily only distantly related RH-like structures such as rhizoids of bryophytes. Our results point to the RH callose deposition as a conserved strategy of soil-anchoring plant cells to cope with mild biotic stress. However, high chitosan concentration prominently disturbs RH intracellular dynamics, tip-localised endomembrane compartments, growth and viability, precluding callose deposition.

• Klíčová slova
• arabidopsis, cell wall, defence, gene expression, signalling,
• MeSH
• Arabidopsis * růst a vývoj   účinky léků   metabolismus   fyziologie   MeSH
• buněčná membrána metabolismus   MeSH
• buněčná stěna * metabolismus   MeSH
• chitosan * farmakologie   MeSH
• glukany * metabolismus   MeSH
• glukosyltransferasy metabolismus   MeSH
• kořeny rostlin * růst a vývoj   metabolismus   účinky léků   MeSH
• proteiny huseníčku * metabolismus   genetika   MeSH
• regulace genové exprese u rostlin účinky léků   MeSH
• vápník metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• callose MeSH Prohlížeč
• chitosan * MeSH
• glukany * MeSH
• glukosyltransferasy MeSH
• proteiny huseníčku * MeSH
• vápník MeSH