Chitosanases represent a class of glycoside hydrolases with high catalytic activity on chitosan but nearly no activity on chitin. Chitosanases can convert high molecular weight chitosan into functional chitooligosaccharides with low molecular weight. In recent years, remarkable progress has been made in the research on chitosanases. This review summarizes and discusses its biochemical properties, crystal structures, catalytic mechanisms, and protein engineering, highlighting the preparation of pure chitooligosaccharides by enzymatic hydrolysis. This review may advance the understandings on the mechanism of chitosanases and promote its industrial applications.
Chitosan/chemistry* ; Chitin ; Glycoside Hydrolases/genetics* ; Protein Engineering ; Oligosaccharides/chemistry* ; Hydrolysis

The biofilms formed by pathogenic microorganisms seriously threaten human health and significantly enhance drug resistance, which urgently call for developing drugs specifically targeting on biofilms. Chitooligosaccharides extracted from shrimp and crab shells are natural alkaline oligosaccharides with excellent antibacterial effects. Nevertheless, their inhibition efficacy on biofilms still needs to be improved. Spirulina (SP) is a microalga with negatively charged surface, and its spiral structure facilitates colonization in the depth of the biofilm. Therefore, the complex of Spirulina and chitooligosaccharides may play a synergistic role in killing pathogens in the depth of biofilm. This research first screened chitooligosaccharides with significant bactericidal effects. Subsequently, Spirulina@Chitooligosaccharides (SP@COS complex was prepared by combining chitooligosaccharides with Spirulina through electrostatic adsorption. The binding of the complex was characterized by zeta potential, z-average size, and fluorescence labeling. Ultraviolet-visible spectroscopy (UV-Vis) showed the encapsulation efficiency and the drug loading efficiency reached up to 90% and 16%, respectively. The prepared SP@COS2 exhibited a profound synergistic inhibition effect on bacterial and fungal biofilms, which was mainly achieved by destroying the cell structure of the biofilm. These results demonstrate the potential of Spirulina-chitooligosaccharides complex as a biofilm inhibitor and provide a new idea for addressing the harm of pathogenic microorganisms.
Humans ; Spirulina ; Anti-Bacterial Agents/chemistry* ; Chitosan/pharmacology* ; Biofilms ; Chitin/pharmacology*

Immunoglobulin Y (IgY) is an effective orally administered antibody used to protect against various intestinal pathogens, but which cannot tolerate the acidic gastric environment. In this study, IgY was microencapsulated by alginate (ALG) and coated with chitooligosaccharide (COS). A response surface methodology was used to optimize the formulation, and a simulated gastrointestinal (GI) digestion (SGID) system to evaluate the controlled release of microencapsulated IgY. The microcapsule formulation was optimized as an ALG concentration of 1.56% (15.6 g/L), COS level of 0.61% (6.1 g/L), and IgY/ALG ratio of 62.44% (mass ratio). The microcapsules prepared following this formulation had an encapsulation efficiency of 65.19%, a loading capacity of 33.75%, and an average particle size of 588.75 μm. Under this optimum formulation, the coating of COS provided a less porous and more continuous microstructure by filling the cracks on the surface, and thus the GI release rate of encapsulated IgY was significantly reduced. The release of encapsulated IgY during simulated gastric and intestinal digestion well fitted the zero-order and first-order kinetics functions, respectively. The microcapsule also allowed the IgY to retain 84.37% immune-activity after 4 h simulated GI digestion, significantly higher than that for unprotected IgY (5.33%). This approach could provide an efficient way to preserve IgY and improve its performance in the GI tract.
Alginic Acid/chemistry* ; Chitin/chemistry* ; Chitosan ; Delayed-Action Preparations ; Digestion ; Drug Compounding ; Drug Liberation ; Gastrointestinal Tract/metabolism* ; Immunoglobulins/metabolism* ; Oligosaccharides

OBJECTIVETo investigate the effect of oligochitosan in promoting intestinal absorption of protoberberine alkaloids in extracts from Corydalis saxicola total alkaloids.

METHODThe in vitro single-pass intestinal perfusion model in rats was established to study the changes in absorption kinetic parameters of dehydrocavidine, berberine hydrochloride and palmatine chloride in C. saxicola total alkaloids after the addition of different concentrations oligochitosan and evaluate the effect of oligochitosan in promoting intestinal absorption of the drugs.

RESULTThe concentration of oligochitosan had different effects on the absorption rate constant (Ka) and apparent permeability coefficient (Peff) of the three active component in rat intestines. Ka and Peff in 0.5% oligochitosan group significantly increased, indicating a stronger effect in promoting the absorption.

CONCLUSIONOligochitosan has a certain effect in promoting the intestinal absorptions of protoberberine alkaloids in C. saxicola total alkaloids.

Animals ; Berberine Alkaloids ; administration & dosage ; pharmacokinetics ; Chitin ; administration & dosage ; analogs & derivatives ; Corydalis ; chemistry ; Drugs, Chinese Herbal ; administration & dosage ; pharmacokinetics ; Intestinal Absorption ; drug effects ; Intestines ; drug effects ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley

Small, cysteine-rich, highly stable antifungal proteins secreted by filamentous Ascomycetes have great potential for the development of novel antifungal strategies. However, their practical application is still limited due to their not fully clarified mode of action. The aim of this work was to provide a deep insight into the antifungal mechanism of Neosartorya fischeri antifungal protein (NFAP), a novel representative of this protein group. Within a short exposure time to NFAP, reduced cellular metabolism, apoptosis induction, changes in the actin distribution and chitin deposition at the hyphal tip were observed in NFAP-sensitive Aspergillus nidulans. NFAP did show neither a direct membrane disrupting-effect nor uptake by endocytosis. Investigation of A. nidulans signalling mutants revealed that NFAP activates the cAMP/protein kinase A pathway via G-protein signalling which leads to apoptosis and inhibition of polar growth. In contrast, NFAP does not have any influence on the cell wall integrity pathway, but an unknown cell wall integrity pathway-independent mitogen activated protein kinase A-activated target is assumed to be involved in the cell death induction. Taken together, it was concluded that NFAP shows similarities, but also differences in its mode of antifungal action compared to two most investigated NFAP-related proteins from Aspergillus giganteus and Penicillium chrysogenum.
Actins ; metabolism ; Antifungal Agents ; pharmacology ; Apoptosis ; drug effects ; Aspergillus nidulans ; cytology ; drug effects ; growth & development ; Cell Membrane ; drug effects ; metabolism ; Cell Wall ; drug effects ; metabolism ; Chitin ; metabolism ; Endocytosis ; drug effects ; Fungal Proteins ; pharmacology ; GTP-Binding Proteins ; metabolism ; Hyphae ; cytology ; drug effects ; Microbial Viability ; drug effects ; Neosartorya ; chemistry ; Signal Transduction ; drug effects

Biological Evolution ; Chitin ; chemistry ; metabolism ; Fungi ; classification ; genetics ; metabolism ; Phylogeny

Chitinases were produced by a lot of microorganisms. Chitinase gene expression in most of the chitinase producing bacteria was inducible by chitin. Low levels of chitinase were observed in the presence of glucose. To date, however, the regulation of such chitinase gene in Bacillus thuringiensis had not been well studied. In this paper, all 77 Bacillus thuringiensis strains were grown in the medium with or without chitin. We measured quantitatively the chitinase activity of the cultures. Moreover, we investigated the suppressive effect of glucose on chitinase of 4 strains. Also we studied the relationship between chitin induction and glucose suppression on chitinase. This investigation demonstrated that all tested B. thuringiensis strains could produce chitinase without chitin. After induction, the chitinolytic activity of 31 tested strains had no obvious response to the inducer, whereas 44 stains increased in different degree. Among these strains, most of them did not markedly increase the levels of chitinase, and many stains simultaneously displayed the expression mode of inducible and constitutive. The glucose inhibited the inductive effect of chitin, but it could not inhibit the basal expression of chitinase. Two strains No. 38 and No. 75 belonged to different expression types. But we just found several different bases in the regulatory region of chitinase genes chiA and chiB from them.
Bacillus thuringiensis ; enzymology ; growth & development ; Base Sequence ; Chitin ; pharmacology ; Chitinases ; biosynthesis ; genetics ; Culture Media ; chemistry ; Culture Techniques ; Glucose ; pharmacology ; Molecular Sequence Data ; Polymorphism, Genetic

We have investigated the degradation of pure Polycaprolactone (PurePCL) and chitin short fiber reinforced Polycaprolactone composite (SFRP) in vitro in order to provide useful scientific basis for clinical application. PurePCL, SFRP and DL-PLA were immersed in 0.9% NaCL solution for periods of 2, 4, 8, 12, 16 and 24 weeks. Then pH values in immersing solution, weight loss and mechanical properties of tested materials were measured and SEM was used to study the change of the materials in the process of degradation. It was shown that the initial strength of SFRP was much higher than that of PurePCL. In the process of degradation of SFRP, the pH values maintained weak acid or remianed neutral. The rate of weight loss of SFRP was faster than that of PurePCL, but slower than that of DL-PLA. The strength and modulus of SFRP did not change much in 24 weeks, compared with the initial ones. In conclusion, the composites have excellent properties and may be optimal for clinical use in reconstruction of chest wall defects as well as in internal fixation of bone fracture.
Biocompatible Materials ; chemistry ; Bone Substitutes ; chemistry ; Chitin ; chemistry ; Composite Resins ; chemistry ; Materials Testing ; Polyesters ; chemistry ; Prostheses and Implants

Chitin short fiber reinforced polycaprolactone composite was prepared by melting blending method. The cytotoxicity and biocompatibility of pure polycaprolactone and of chitin short fiber reinforced polycaprolactone composite were investigated in order to provide useful scientific basis for clinical application. The biocompatibility of pure polycaprolactone and that of chitin short fiber reinforced polycaprolactone composite were evaluated by a series of tests, including cytotoxicity test in vitro, acute systemic toxicity test, hemolysis test, pyrogen test and sensitivity test. The results showed that the cytotoxicity scores of the two materials were grade 0 and the growth and proliferation of the cultured cells were not significantly inhibited by the two materials. There were no potential allergic materials in the composites and the maceration extract showed no hemolytic reaction, no acute systemic toxicity and no pyrogen reaction. We conclude that the composites have fine biocompatibility and are safe for clinical use in the reconstruction treatment for chest wall defect.
Biocompatible Materials ; chemistry ; Bone Substitutes ; chemistry ; Chitin ; chemistry ; Materials Testing ; Polyesters ; chemistry

Hydroxyethyl chitin (HECH) is a water soluble chitin derivative made by etherification of chitin, ethylene chlorohydrin was used as etherification reagent in this reaction. A novel interpenetrating polymer network (IPN) composed of HECH/PAA was prepared. The IR spectra confirmed that HECH/PAA was formed through chemical bond interaction. The sensitivity of this hydrogel to temperature and pH was studied. The swelling ratio of this hydrogel in artificial intestinal juice is much greater than that in artificial gastric juice. The IPN hydrogel exhibited a typical pH-sensitivity, and its degree of swelling ratio increased with the increase of temperature. The sustained-release drug system of Dichlofenac potassium was prepared by using HECH/PAA as the drug carrier. The release experiment showed a perfect release behavior in artificial intestinal juice. This IPN is expected to be used as a good drug delivery system of enteric medicine.
Acrylates ; administration & dosage ; chemistry ; Anti-Inflammatory Agents, Non-Steroidal ; administration & dosage ; Chitin ; administration & dosage ; analogs & derivatives ; chemistry ; Delayed-Action Preparations ; Diclofenac ; administration & dosage ; Drug Carriers ; chemical synthesis ; Drug Delivery Systems ; Hydrogel, Polyethylene Glycol Dimethacrylate ; administration & dosage ; chemistry ; Hydrogen-Ion Concentration