Chitosan: Deacetylated CHITIN, a linear polysaccharide of deacetylated beta-1,4-D-glucosamine. It is used in HYDROGEL and to treat WOUNDS.Chitin: A linear polysaccharide of beta-1->4 linked units of ACETYLGLUCOSAMINE. It is the second most abundant biopolymer on earth, found especially in INSECTS and FUNGI. When deacetylated it is called CHITOSAN.Drug Carriers: Forms to which substances are incorporated to improve the delivery and the effectiveness of drugs. Drug carriers are used in drug-delivery systems such as the controlled-release technology to prolong in vivo drug actions, decrease drug metabolism, and reduce drug toxicity. Carriers are also used in designs to increase the effectiveness of drug delivery to the target sites of pharmacological actions. Liposomes, albumin microspheres, soluble synthetic polymers, DNA complexes, protein-drug conjugates, and carrier erythrocytes among others have been employed as biodegradable drug carriers.Nanoparticles: Nanometer-sized particles that are nanoscale in three dimensions. They include nanocrystaline materials; NANOCAPSULES; METAL NANOPARTICLES; DENDRIMERS, and QUANTUM DOTS. The uses of nanoparticles include DRUG DELIVERY SYSTEMS and cancer targeting and imaging.Particle Size: Relating to the size of solids.Hexuronic Acids: Term used to designate tetrahydroxy aldehydic acids obtained by oxidation of hexose sugars, i.e. glucuronic acid, galacturonic acid, etc. Historically, the name hexuronic acid was originally given to ascorbic acid.Glucuronic Acid: A sugar acid formed by the oxidation of the C-6 carbon of GLUCOSE. In addition to being a key intermediate metabolite of the uronic acid pathway, glucuronic acid also plays a role in the detoxification of certain drugs and toxins by conjugating with them to form GLUCURONIDES.Biocompatible Materials: Synthetic or natural materials, other than DRUGS, that are used to replace or repair any body TISSUES or bodily function.Chemistry, Pharmaceutical: Chemistry dealing with the composition and preparation of agents having PHARMACOLOGIC ACTIONS or diagnostic use.Alginates: Salts of alginic acid that are extracted from marine kelp and used to make dental impressions and as absorbent material for surgical dressings.Holmium: Holmium. An element of the rare earth family of metals. It has the atomic symbol Ho, atomic number 67, and atomic weight 164.93.Spectroscopy, Fourier Transform Infrared: A spectroscopic technique in which a range of wavelengths is presented simultaneously with an interferometer and the spectrum is mathematically derived from the pattern thus obtained.Drug Delivery Systems: Systems for the delivery of drugs to target sites of pharmacological actions. Technologies employed include those concerning drug preparation, route of administration, site targeting, metabolism, and toxicity.Delayed-Action Preparations: Dosage forms of a drug that act over a period of time by controlled-release processes or technology.Drug Compounding: The preparation, mixing, and assembling of a drug. (From Remington, The Science and Practice of Pharmacy, 19th ed, p1814)Nanocapsules: Nanometer-sized, hollow, spherically-shaped objects that can be utilized to encapsulate small amounts of pharmaceuticals, enzymes, or other catalysts (Glossary of Biotechnology and Nanobiotechnology, 4th ed).Microspheres: Small uniformly-sized spherical particles, of micrometer dimensions, frequently labeled with radioisotopes or various reagents acting as tags or markers.Technology, Pharmaceutical: The application of scientific knowledge or technology to pharmacy and the pharmaceutical industry. It includes methods, techniques, and instrumentation in the manufacture, preparation, compounding, dispensing, packaging, and storing of drugs and other preparations used in diagnostic and determinative procedures, and in the treatment of patients.

*  Chitosan Uses, Benefits & Side Effects - Drugs.com Herbal Database

Learn about the uses and potential benefits of Chitosan including dosage guidelines, side effects, interactions and safety/ ... Chitosan has been used in the cosmetic and fabric industry.. General uses There is some evidence of the effect of chitosan on ... Chitosan dressings are sometimes used in emergency rooms to control bleeding. Chitosan has been used in various drug delivery ... What is Chitosan?. Chitin is a cellulose-like biopolymer found mainly in the exoskeleton of marine animals such as shrimp, ...

*  IJMS | Free Full-Text | Biocompatibility of Genipin and Glutaraldehyde Cross-Linked Chitosan Materials in the Anterior Chamber...

The present work aims to further investigate the in vivo biocompatibility of GP-treated chitosan (GP-chi group) by adopting the ... The 7-mm-diameter membrane implants made from either non-cross-linked chitosan or chemically modified materials with a cross- ... We recently demonstrated that the genipin (GP) cross-linked chitosan is compatible with human retinal pigment epithelial cells ... In summary, the intracameral tissue response to the chemically modified chitosan materials strongly depends on the selection of ...

*  Evaluation of cytotoxicity and mechanism of apoptosis of doxorubicin using folate-decorated chitosan nanoparticles for targeted...

1H NMR spectra of a chitosan, b CNP-FA conjugate, and c schematic representation of folic acid conjugated to chitosan ... Ji QX, Zhong DY, Lü R et al (2009) In vitro evaluation of the biomedical properties of chitosan and quaternized chitosan for ... Nanoparticles Chitosan Folic acid Doxorubicin Retinoblastoma Targeted drug delivery 1 Introduction. Cancer is a debilitating ... 1997a, b). Briefly, 2 ml of an aqueous solution of TPP (2.91 mg/ml) was slowly added drop wise into 10 ml of chitosan solution ...

*  Gadolinium-loaded chitosan nanoparticles for neutron-capture therapy: Influence of micrometric properties of the nanoparticles...

Gadolinium-loaded chitosan nanoparticles for neutron-capture therapy: Influence of micrometric properties of the nanoparticles ... As a nanoparticulate device for controlled delivery of Gd in NCT, the authors have developed gadolinium-loaded chitosan ... could be prepared by using chitosans with different molecular weights. Gd-nanoCPs incorporating 1.2mg of natural Gd were ...

*  Specification of chitosan oligomer / spec 6 / Dalwoo-chitoSan / chitin, chitosan, chitosan oligomer, glucosamine-sulfate

... chitosan oligomer in various grades made from crab shell / Dalwoo-chitoSan ... Illegal Copy of Namo WebEditor] first quality chitin, chitosan, ... Dalwoo-chitoSan supply first quality bulk chitin, chitosan and ... Food grade Chitosan. Pharmaceutical grade Chitosan. Chitin. Carboxylmethyl Chitosan. Technical grade Chitosan. Liquid Chitosan ... Chitosan Oligosaccharide. Chitosan Oligosaccharide is obtained by an enzymatic hydrolysis of chitosan using chitosanase.. ...

*  Effects of Chitosan on Candida albicans: Conditions for Its Antifungal Activity : Table 1

... in the absence or presence of chitosan, 20 μg·mL−1 plus the indicated amounts of chitosan in a water bath at 30°C. After 2 min ... Table 1: Kinetic constants of 86Rb+ uptake; effect of chitosan on the strain C. albicans ATCC 10231. Uptake of 86Rb+ was ...

*  PubMed Journals Articles About 'Tight Junction Modulation Chitosan Nanoparticles Comparison With Chitosan'

Tight Junction Modulation Chitosan Nanoparticles Comparison With Chitosan PubMed Journal Articles published on BioPortfolio , ... FTIR spectra showed that the mushroom chitosan were similar to chitosan from animal sources. Chitosan films were prepared using ... In this study, three different carboxymethyl chitosans (CMCs), namely O-carboxymethyl chitosan (OC), N-carboxymethyl chitosan ( ... Chitosan-Based Multifunctional Platforms for Local Delivery of Therapeutics.. Chitosan has been widely used as a key ...

*  Lokaverkefni: "Chitosan Derivatives that mimic Antimicrobial Peptides. Synthesis, characterization and antimicrobial activity....

N-guanidyl chitosan showed good antimicrobial activity while N-acetyl-guanidyl chitosan had less activity. The syntheses of N- ... The syntheses of N,N,N-trimethyl chitosan and N-acetyl-N',N',N'-trimethyl chitosan were successful and the antimicrobial ... The syntheses of N-guanidyl chitosan and N-acetyl-guanidyl chitosan were achieved for the first time using O-TBDMS protection. ... valeroyl-N',N',N'-trimethyl chitosan and N-valeroyl-guanidyl chitosan were not successful due to the formation of lactam and/or ...

*  ADSORPTION STUDIES OF KETOCONAZOLE WITH CHITOSAN - Progress in the Chemistry and Application of Chitin and its Derivatives -...

The test results show that the antifungal agent is adsorbed onto the chitosan in the pH ranges used, and the binding ability of ... It was observed that the average sorption, depending on the variety of chitosan, was located in the limit from 94% to 100%. The ... 7. Meler J.; (2008) Influence of different change on bioavailability of medicine chitosans antiphlogistic drugs. Progress on ... the modified and modified chitosans. In: Progress on Chemistry and Application of Chitin and its Derivatives. Vol. IX (ed.: H. ...

*  Evaluation of Chitosan Coagulation as a Sustainable Method for Point of Use Drinking Water Treatment in Developing Countries| ...

Measure the ability metal ions, chitosans and chitosan nanoparticles in combination to improve microbial quality of stormwater ... Evaluate the user acceptability of chitosan and chitosan nanoparticles for treatment of collected rainwater in Thailand ... and an evaluation of chitosan and chitosan nanoparticles for improving the quality of this water. In addition, we have added a ... how metal ions and chitosan or chitosan nanoparticles can be used to achieve the necessary level of treatment. There are ...

*  Nano-sizing Chitosan for Wound Healing, Anti-aging

... investigated the antibacterial properties of chitosan for cosmetic and pharmaceutical uses. She found that the material ... Nano-sizing Chitosan. To investigate the uses for chitosan, Leonida's team first deacetylated chitin. "[Deacetylation] is not a ... including chitosan. We wanted to increase the uptake and enhance bioavailability, and nano-sized chitosan overcomes the ... Chitosan] is able to bind ions, so some speculate that it chelates metal ions inside the microbes to prevent their growth. In ...

*  Patent US6733209 - Chitosan enhanced erosion control rolls - Google Patents

Chitosan may be added to one or more device elements to assist in removing unwanted silt and contamination from passing fluid. ... A chitosan enhanced erosion control device is described. A walled elongated core member is disclosed having a first open end, a ... Chitosan is available commercially from several sources, with one example being Vanson, Inc. of Redmond, Wash. Chitosan can be ... For example, pieces of a chitosan time release gel may be distributed in several blanket locations, or powdered chitosan may be ...

*  Surface Modification Of PLGA Nanoparticles By Low Molecular Weight Chitosan To Enhance Mucoadhesion

Chitosan has been reported as a mucoadhesive polymer due to its amine groups (NH2) [3]. The current research intends to enhance ... Surface modification of PLGA nanoparticles by low molecular weight chitosan to enhance mucoadhesion. ... the mucoadhesiveness of PLGA nanoparticles by coating with low molecular weight chitosan (LMWC). These nanoparticles were ...

*  Chitosan | TriStar Health

Chitosan is the deacetylated form.) Uses Principal Proposed Uses None Other... ... Learn more about Chitosan at TriStar Health Related Terms Chitin ( ... Chitosan can deplete the body of certain minerals (see Safety Issues below). For this reason, when using chitosan, it may be ... Chitosan is a form of fiber chemically processed from crustacean shells. Like other forms of fiber, such as oat bran, chitosan ...

*  About Chitosan - Biophrame Technologies

Chitosan Chitosan is a biopolymer derived from chitin (a naturally occurring polysaccharide widely distributed in nature, ... Chemically, Chitosan is a copolymer composed by β-(1→4)-2-acetamido-D-glucose and β-(1→4)-2-amino-D-glucose units (see figure ... reactive hydroxyl and amino groups that help Chitosan display excellent biocompatibility, biodegradability, non-toxicity, ...

*  More Chitosan information

What is Chitosan? Functions of Chitosan History of Chitosan Fat Binding and Weight Loss The Fat Fighting Fiber of the Future. ... Chitosan: The Nutrient that Binds Fat WHAT EXACTLY IS CHITOSAN? Chitosan is a natural product derived from chitin, a ... Not only is chitosan a super fat fighting fiber, it additionally provides all of the above benefits. top of page Chitosan Fiber ... Chitosan Fiber Loves Fat and Other Stuff The Body Can Turn Into Fat Chitosan has a powerful natural magnetic attraction for ...

*  Chitosan from shrimp shells, practical grade | Sigma-Aldrich

Chitosan for your research needs. Find product specific information including CAS, MSDS, protocols and references. ... Chitosan, Chitosan and Chitin, Chitosans (Animal Origin), Materials Science, Natural Polymers and Biopolymers, Polymer Science ... What is the solubility of Chitosan, Product 417963? Product No. 417963 is tested for solubility using 50 mg of chitosan in 5 mL ... What are some uses for Chitosan, Product 417963? Chitosan has recently found many applications in the field of biomaterials. It ...

*  Chitosan Market - Size, Share, Report, 2024 | Fractovia

Chitosan Market size was valued over USD 1.52 billion in 2015 and is forecast to experience gains exceeding 16% CAGR between ... U.S. Chitosan Market size, by application, 2013-2024 (USD million). Chitosan market revenue in food & beverages sector is ... Chitosan industry size is expected to grow at a rate of 16% over the period of 2016-2024, owing to its wide applications in ... Asia Pacific chitosan market is expected to record significant gains of 18% over 2016-2024, owing to its growing use as bio- ...

*  Removal of lead from aqueous solutions by complexation ultrafiltration with chitosan on Environmental XPRT

The removal of lead from aqueous dilute solutions by complexation-ultrafiltration with chitosan was studied. Experiments were ... Article Removal of lead from aqueous solutions by complexation ultrafiltration with chitosan. ... No comments were found for Removal of lead from aqueous solutions by complexation ultrafiltration with chitosan. Be the first ... Removal of lead from aqueous solutions by complexation ultrafiltration with chitosan. 0 ...

*  Benefits of Chitosan Oligosaccharides / Dalwoo-chitoSan

Illegal Copy of Namo WebEditor] Remarkable feature of chitosan oligosaccharides produced by an enzymatic method using ... Chitosan Oligosaccharide is a non-toxic functional amino sugar of low molecular weight. Chitosan Oligosaccharide is a mixture ... While chitosan works only from the stomach and intestines as it is not absorbed into the system, Chitosan Oligosaccharide can ... Chitosan Oligosaccharide is obtained by an enzymatic hydrolysis of chitosan using chitosanase. ...

*  IJMS | Free Full-Text | Effect of the Characters of Chitosans Used and Regeneration Conditions on the Yield and Physicochemical...

Different concentrations of acetic acid were used to dissolve chitosans of 61.7% and 94.9% degree of deacetylation (DD), and ... The DD and structure of chitosan was changed insignificantly after the regeneration process. ... The objective of this study was to explore the effect of the character of chitosans used, and the regeneration conditions ... Hsu, C.H.; Chen, S.K.; Chen, W.Y.; Tsai, M.L.; Chen, R.H. Effect of the Characters of Chitosans Used and Regeneration ...

*  "Chitosan Decontamination with Non-Thermal Nitrogen Plasma to Enable In" by Andrew R. Crofton

All plasma-sterilized chitosan+IL-12 (n=11) and 92% of unsterile chitosan+IL-12 (n=13) treated mice rejected tumors upon re- ... Potential medical applications for chitosan are extensive and many have shown impressive results. However, chitosan is ... of C57Bl/6 mice treated with unsterile chitosan+IL-12 and plasma-sterilized chitosan+IL-12, respectively, but only 8% (n=12) ... NtNP treatment of the resultant chitosan powder produced a sterile chitosan with endotoxin levels ,2.50 EU/g, but further ...

*  China Water Solution Chitosan, Water Solution Chitosan Manufacturers, Suppliers | Made-in-China.com

Select 2017 high quality Water Solution Chitosan products in best price from certified Chinese Product Solution manufacturers, ... Chitosan CAS: 222-311-2 Food Additiv Food Grade Chitosan FOB Price: US $1 / kg Min. Order: 10 kg ... Chitosan Food Additive Food Grade Chitosan FOB Price: US $1 / kg Min. Order: 1 kg ... Chitosan Natural Polymer Chitosan FOB Price: $200 - $500 / KG Min. Order: 500 KG ...

*  Highly Immunogenic Trimethyl Chitosan-based Delivery System for Intranasal Lipopeptide Vaccines against Group A Streptococcus |...

Results: Trimethyl chitosan (TMC)-coated liposomes that bore a B-cell epitope derived from GAS Mprotein, stimulated potent ... Results: Trimethyl chitosan (TMC)-coated liposomes that bore a B-cell epitope derived from GAS Mprotein, stimulated potent ... Highly Immunogenic Trimethyl Chitosan-based Delivery System for Intranasal Lipopeptide Vaccines against Group A Streptococcus. ... Highly Immunogenic Trimethyl Chitosan-based Delivery System for Intranasal Lipopeptide Vaccines against Group A Streptococcus. ...

*  JoF | Free Full-Text | Omics for Investigating Chitosan as an Antifungal and Gene Modulator

Genome sequencing of P. chlamydosporia reveals a wide gene machinery to degrade and assimilate chitosan. Chitosan increases P. ... The use of chitosan in clinical medicine to control infections by fungal pathogens such as Candida spp. is one of its most ... Omics studies allow understanding the mode of action of chitosan and help its development as an antifungal and gene modulator. ... Chitosan increases intracellular oxidative stress, then permeabilizes the plasma membrane of sensitive filamentous fungus ...

ChitosanChitinCharged Aerosol Release Experiment: The Charged Aerosol Release Experiment also known as CARE, is a project run by NASA which will use a rocket to release dust in the upper atmosphere to form a dusty plasma in space. NASA plans to trigger cloud formation around the rocket's exhaust particles.Nanoparticle: Nanoparticles are particles between 1 and 100 nanometers in size. In nanotechnology, a particle is defined as a small object that behaves as a whole unit with respect to its transport and properties.Coulter counter: 150px|thumb|right|The tip of the Coulter counter in a buffer solution, counting cells in solution.Surface modification of biomaterials with proteins: Biomaterials are materials that are used in contact with biological systems. Biocompatibility and applicability of surface modification with current uses of metallic, polymeric and ceramic biomaterials allow alteration of properties to enhance performance in a biological environment while retaining bulk properties of the desired device.ACS Medicinal Chemistry Letters: ACS Medicinal Chemistry Letters is a peer-reviewed academic journal in the field of medicinal chemistry. Founded in 2009, this online journal is published monthly by the American Chemical Society.Immobilized enzyme: An immobilized enzyme is an enzyme that is attached to an inert, insoluble material such as calcium alginate (produced by reacting a mixture of sodium alginate solution and enzyme solution with calcium chloride). This can provide increased resistance to changes in conditions such as pH or temperature.Holmium(III) oxideDiffuse reflectance infrared fourier transform: Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS)C.-P.Neural drug delivery systems: Neural drug delivery is the next step beyond the basic addition of growth factors to nerve guidance conduits. Drug delivery systems allow the rate of growth factor release to be regulated over time, which is critical for creating an environment more closely representative of in vivo development environments.Sustained release dosage forms: Sustained release dosage forms are designed to release a drug at a predetermined rate in order to maintain a constant drug concentration for a specific period of time with minimum side effects. This can be achieved through a variety of formulations, including liposomes and drug-polymer conjugates (an example being hydrogels).Microsphere: Microspheres are small spherical particles, with diameters in the micrometer range (typically 1 μm to 1000 μm (1 mm)). Microspheres are sometimes referred to as microparticles.

(1/1030) Mode of action of chitin deacetylase from Mucor rouxii on N-acetylchitooligosaccharides.

The mode of action of chitin deacetylase from the fungus Mucor rouxii on N-acetylchitooligosaccharides with a degree of polymerization 1-7 has been elucidated. Identification of the sequence of chitin oligomers following enzymatic deacetylation was verified by the alternative use of two specific exo-glycosidases in conjunction with HPLC. The results were further verified by 1H-NMR spectroscopy. It was observed that the length of the oligomer is important for enzyme action. The enzyme cannot effectively deacetylate chitin oligomers with a degree of polymerization lower than three. Tetra-N-acetylchitotetraose and penta-N-acetylchitopentaose are fully deacetylated by the enzyme, while in the case of tri-N-acetylchitotriose, hexa-N-acetylchitohexaose and hepta-N-acetylchitoheptaose the reducing-end residue always remains intact. Furthermore, the enzyme initially removes an acetyl group from the nonreducing-end residue of all chitin oligomers with a degree of polymerization higher than 2, and further catalyses the hydrolysis of the following acetamido groups in a processive fashion. The results are in agreement with the mode of action that the same enzyme exhibits on partially deacetylated water soluble chitosan polymers.  (+info)

(2/1030) Chs7p, a new protein involved in the control of protein export from the endoplasmic reticulum that is specifically engaged in the regulation of chitin synthesis in Saccharomyces cerevisiae.

The Saccharomyces cerevisiae CHS7 gene encodes an integral membrane protein located in the ER which is directly involved in chitin synthesis through the regulation of chitin synthase III (CSIII) activity. In the absence of CHS7 product, Chs3p, but not other secreted proteins, is retained in the ER, leading to a severe defect in CSIII activity and consequently, to a reduced rate of chitin synthesis. In addition, chs7 null mutants show the yeast phenotypes associated with a lack of chitin: reduced mating efficiency and lack of the chitosan ascospore layer, clear indications of Chs7p function throughout the S. cerevisiae biological cycle. CHS3 overexpression does not lead to increased levels of CSIII because the Chs3p excess is retained in the ER. However, joint overexpression of CHS3 and CHS7 increases the export of Chs3p from the ER and this is accompanied by a concomitant increase in CSIII activity, indicating that the amount of Chs7p is a limiting factor for CSIII activity. Accordingly, CHS7 transcription is increased when elevated amounts of chitin synthesis are detected. These results show that Chs7p forms part of a new mechanism specifically involved in Chs3p export from the ER and consequently, in the regulation of CSIII activity.  (+info)

(3/1030) Modification of chitosan to improve its hypocholesterolemic capacity.

Cholestyramine is the most widely used bile acid sequestrant in the treatment of hypercholesterolemia. However, cholestyramine has unpleasant side effects as a consequence of its hydrophobic backbone. Therefore, high-capacity bile acid sequestering biopolymers with cationic chitosan derivatives were developed, because electrostatic interactions are important for binding with bile acid anions. Dialkylaminoalkylation and reductive amination of chitosan were done to add dialkylaminoalkyl and an additional free amino group at a hydroxyl site in the chitosan backbone respectively and the amino-derivatized chitosan derivatives were quaternized with methyl iodide to produce a cationic polyelectrolyte. The in vitro bile acid binding capacity of the chitosan derivatives in aqueous NaCl was measured by reversed-phase HPLC. The binding capacities of sodium glycocholate (a major bile acid) to chitosan, DEAE-chitosan, quaternized DEAE-chitosan, and cholestyramine were 1.42, 3.12, 4.06, and 2.78 mmol/g resin, respectively. With quaternized DEAE-chitosan, the bile acid binding capacity increased approximately 50% over that of cholestyramine. The bile acid binding capacity of dialkylaminoalkyl chitosan derivatives increased with the number of carbons in the alkyl groups, indicating that hydrophobic interaction is a secondary factor for the sequestration of bile acids.  (+info)

(4/1030) Development of bacterial contamination during production of yeast extracts.

Baker's yeast suspensions having bacterial populations of 10(6) and 10(8) CFU/ml were subjected to autolysis processes designed to obtain yeast extracts (YE). The bacterial contaminants added to the yeast cell suspensions were produced with spent broths obtained from a commercial yeast production plant and contained 59% cocci (Leuconostoc, Aerococcus, Lactococcus) as well as 41% bacilli (Bacillus). Autolyses were conducted at four different pH levels (4.0, 5.5, 7.0, and 8.5) and with two autolysis-promoting agents (ethyl acetate and chitosan). Processing parameters were more important than the initial bacterial population in the development of contaminating bacteria during manufacture of YE. Drops in the viable bacterial population after a 24-h autolysis were observed when pH was adjusted to 4.0 or when ethyl acetate was added. A significant interaction was found between the effects of pH and autolysis promoters on the bacterial population in YE, indicating that the activity of ethyl acetate, as opposed to that of chitosan, was not influenced by pH.  (+info)

(5/1030) Oligogalacturonic acid and chitosan reduce stomatal aperture by inducing the evolution of reactive oxygen species from guard cells of tomato and Commelina communis.

Stomatal opening provides access to inner leaf tissues for many plant pathogens, so narrowing stomatal apertures may be advantageous for plant defense. We investigated how guard cells respond to elicitors that can be generated from cell walls of plants or pathogens during pathogen infection. The effect of oligogalacturonic acid (OGA), a degradation product of the plant cell wall, and chitosan (beta-1,4-linked glucosamine), a component of the fungal cell wall, on stomatal movements were examined in leaf epidermis of tomato (Lycopersicon esculentum L.) and Commelina communis L. These elicitors reduced the size of the stomatal aperture. OGA not only inhibited light-induced stomatal opening, but also accelerated stomatal closing in both species; chitosan inhibited light-induced stomatal opening in tomato epidermis. The effects of OGA and chitosan were suppressed when EGTA, catalase, or ascorbic acid was present in the medium, suggesting that Ca(2+) and H(2)O(2) mediate the elicitor-induced decrease of stomatal apertures. We show that the H(2)O(2) that is involved in this process is produced by guard cells in response to elicitors. Our results suggest that guard cells infected by pathogens may close their stomata via a pathway involving H(2)O(2) production, thus interfering with the continuous invasion of pathogens through the stomatal pores.  (+info)

(6/1030) Maintenance of CD34 expression during proliferation of CD34+ cord blood cells on glycosaminoglycan surfaces.

Recent studies have indicated that glycosaminoglycan (GAG) interactions with hematopoietic progenitors play a significant role in the regulation of hematopoiesis. However, the details of these interactions are not clear. In this study, we examined the role of soluble and immobilized GAGs in the proliferation of CD34+ cells. Chitosan, a cationic polysaccharide, was used to immobilize GAGs in ionic complex membranes. The GAGs studied were heparin, hyaluronate, and chondroitin sulfates A, B, and C. CD34-enriched umbilical cord blood cells were seeded onto tissue culture plates coated with the GAG-chitosan complex membranes. Cultures were maintained in medium supplemented with stem cell factor and interleukin 3 for up to six weeks, during which total and CD34+ cell numbers were determined by flow cytometry. Total cell number expansion ranged from 25-fold to 40-fold after six weeks. However, only heparin and chondroitin sulfate B (CSB) surfaces retained a significant CD34+ fraction. All other surfaces exhibited declines in CD34 expression, with negligible CD34+ percentages remaining after four weeks. In contrast, heparin and CSB surfaces exhibited CD34+ fractions as high as 90% after four weeks. GAG desorption studies indicated that the observed effects were partly mediated by desorbed GAGs in a concentration dependent manner. Subsequent studies showed that sustained high (160 microg/ml) heparin levels had toxic effects, while the same concentration of CSB exhibited more rapid early proliferation of CD34+ cells. In conclusion, this culture system has demonstrated the ability to produce simultaneous proliferation and CD34+ cell enrichment of a partially purified cord blood population by controlling the nature and levels of GAG moieties to which the cells are exposed. The results indicate that specific GAGs can significantly influence the growth and differentiation characteristics of cultured CD34+ cells.  (+info)

(7/1030) Purification, characterization, and gene analysis of a chitosanase (ChoA) from Matsuebacter chitosanotabidus 3001.

The extracellular chitosanase (34,000 M(r)) produced by a novel gram-negative bacterium Matsuebacter chitosanotabidus 3001 was purified. The optimal pH of this chitosanase was 4.0, and the optimal temperature was between 30 and 40 degrees C. The purified chitosanase was most active on 90% deacetylated colloidal chitosan and glycol chitosan, both of which were hydrolyzed in an endosplitting manner, but this did not hydrolyze chitin, cellulose, or their derivatives. Among potential inhibitors, the purified chitosanase was only inhibited by Ag(+). Internal amino acid sequences of the purified chitosanase were obtained. A PCR fragment corresponding to one of these amino acid sequences was then used to screen a genomic library for the entire choA gene encoding chitosanase. Sequencing of the choA gene revealed an open reading frame encoding a 391-amino-acid protein. The N-terminal amino acid sequence had an excretion signal, but the sequence did not show any significant homology to other proteins, including known chitosanases. The 80-amino-acid excretion signal of ChoA fused to green fluorescent protein was functional in Escherichia coli. Taken together, these results suggest that we have identified a novel, previously unreported chitosanase.  (+info)

(8/1030) Characterization of a novel, antifungal, chitin-binding protein from Streptomyces tendae Tu901 that interferes with growth polarity.

The afp1 gene, which encodes the antifungal protein AFP1, was cloned from nikkomycin-producing Streptomyces tendae Tu901, using a nikkomycin-negative mutant as a host and screening transformants for antifungal activity against Paecilomyces variotii in agar diffusion assays. The 384-bp afp1 gene has a low G+C content (63%) and a transcription termination structure with a poly(T) region, unusual attributes for Streptomyces genes. AFP1 was purified from culture filtrate of S. tendae carrying the afp1 gene on the multicopy plasmid pIJ699. The purified protein had a molecular mass of 9,862 Da and lacked a 42-residue N-terminal peptide deduced from the nucleotide sequence. AFP1 was stable at extreme pH values and high temperatures and toward commercial proteinases. AFP1 had limited similarity to cellulose-binding domains of microbial plant cell wall hydrolases and bound to crab shell chitin, chitosan, and cell walls of P. variotii but showed no enzyme activity. The biological activity of AFP1, which represents the first chitin-binding protein from bacteria exhibiting antifungal activity, was directed against specific ascomycetes, and synergistic interaction with the chitin synthetase inhibitor nikkomycin inhibited growth of Aspergillus species. Microscopy studies revealed that fluorescein-labeled AFP1 strongly bound to the surface of germinated conidia and to tips of growing hyphae, causing severe alterations in cell morphogenesis that gave rise to large spherical conidia and/or swollen hyphae and to atypical branching.  (+info)



cationic

  • Chitosan is a naturally occurring cationic polysaccharide and has attracted much attention in the past decade as an important ophthalmic biomaterial. (mdpi.com)
  • Chitosan, a naturally occurring cationic polysaccharide, is obtained by the deacetylation of chitin. (mdpi.com)

Activity

  • The aim of this study was to synthesize six different chitosan derivatives that mimic the polycationic structure of antimicrobial peptides and test their antimicrobial activity on two gram positive and two gram negative bacterial species. (skemman.is)
  • The syntheses of N,N,N-trimethyl chitosan and N-acetyl-N',N',N'-trimethyl chitosan were successful and the antimicrobial activity was comparable to what had previously been published. (skemman.is)
  • N-guanidyl chitosan showed good antimicrobial activity while N-acetyl-guanidyl chitosan had less activity. (skemman.is)