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1.
Biochemistry (Mosc) ; 85(Suppl 1): S154-S176, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32087058

RESUMO

In this review, we present the data on the natural occurrence of chitin and its partially or fully deacetylated derivative chitosan, as well as their properties, methods of modification, and potential applications of derivatives with bactericidal, fungicidal, and antioxidant activities. The structure and physicochemical characteristics of the polymers, their functions, and features of chitin microbial synthesis and degradation, including the processes occurring in nature, are described. New data on the hydrolytic microorganisms capable of chitin degradation under extreme conditions are presented. Special attention is focused on the effect of physicochemical characteristics of chitosan, including molecular weight, degree of deacetylation, polydispersity index, and number of amino group derivatives (quaternized, succinyl, etc.) on the antimicrobial and antioxidant properties of modified polymers that can be of particular interest for biotechnology, medicine, and agriculture. Analysis of the available literature data confirms the importance of fundamental research to broaden our knowledge on the occurrence of chitin and chitosan in nature, their role in global biosphere cycles, and prospects of applied research aimed at using chitin, chitosan, and their derivatives in various aspects of human activity.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antioxidantes/farmacologia , Quitosana/análogos & derivados , Quitosana/farmacologia , Fungicidas Industriais/farmacologia , Antibacterianos/química , Antibacterianos/metabolismo , Antifúngicos/química , Antifúngicos/metabolismo , Antioxidantes/química , Antioxidantes/metabolismo , Bactérias/metabolismo , Biotecnologia , Quitosana/química , Quitosana/metabolismo , Proteção de Cultivos , Descoberta de Drogas , Fungicidas Industriais/química , Fungicidas Industriais/economia , Fungicidas Industriais/metabolismo , Humanos , Hidrólise , Peso Molecular , Polímeros
2.
J Agric Food Chem ; 68(1): 358-368, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31815446

RESUMO

Nanoscale chitosan materials exhibit size-specific properties that make them useful in agri-food and biomedical applications. Chitosan nanoparticles (Chnps) are being explored as nanocarrier platforms to increase oral bioavailability of drugs and nutraceuticals, but little is known of their fate and transformations in the gastrointestinal tract (GIT) or of their potential toxicity. Here, the GIT fate and cytotoxicity of Chnps, soluble starch-coated Chnps (SS-Chnps), and bulk chitosan powder (Chp), were assessed using a 3-phase simulated digestion and an in vitro cellular small intestinal epithelium model. Physico-chemical characterization revealed dissolution of Chp, but not of Chnps or SS-Chnps, during the gastric phase of digestion, stability of the starch coating of SS-Chnps in the oral and gastric phases, and agglomeration of all materials during the small intestinal phase. A slight but significant (10%, p < 0.01) increase in cytotoxicity (LDH release) was observed with exposure to digested Chnps but not Chp or SS-Chnps.


Assuntos
Quitosana/química , Quitosana/metabolismo , Epitélio/metabolismo , Intestino Delgado/metabolismo , Nanopartículas/química , Nanopartículas/metabolismo , Disponibilidade Biológica , Células CACO-2 , Quitosana/toxicidade , Trato Gastrointestinal/metabolismo , Humanos , Cinética , Modelos Biológicos , Nanopartículas/toxicidade , Tamanho da Partícula
3.
J Sci Food Agric ; 100(2): 794-802, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31612484

RESUMO

BACKGROUND: Low-sodium sausages were manufactured using sodium substitution and biopolymer encapsulation. A diet comprising 10% treatment sausages (six treatment groups: C (100% NaCl), T1 (55% sodium substitute + 45% saltwort salt), T2 (55% sodium substitute + 45% saltwort salt with chitosan), T3 (55% sodium substitute + 45% saltwort salt with cellulose), T4 (55% sodium substitute + 45% saltwort salt with dextrin), and T5 (55% sodium substitute + 45% saltwort salt with pectin)) was added to a 90% commercial mouse diet for 4 weeks. RESULTS: Subacute toxicity, hematology, liver function, and organ weight tests in low-sodium sausage groups showed results similar to those of the control group, and all toxicity test levels were within normal ranges. CONCLUSIONS: All low-sodium sausage types tested are suggested to be safe in terms of subacute toxicity. Moreover, low-sodium sausages can be manufactured by biopolymer encapsulation of saltwort using pectin, chitosan, cellulose, and dextrin without toxicity. © 2019 Society of Chemical Industry.


Assuntos
Biopolímeros/análise , Aditivos Alimentares/análise , Manipulação de Alimentos/métodos , Produtos da Carne/análise , Salsola/química , Sódio/análise , Animais , Biopolímeros/metabolismo , Biopolímeros/toxicidade , Celulose/análise , Celulose/metabolismo , Celulose/toxicidade , Quitosana/análise , Quitosana/metabolismo , Quitosana/toxicidade , Feminino , Aditivos Alimentares/metabolismo , Aditivos Alimentares/toxicidade , Manipulação de Alimentos/instrumentação , Masculino , Produtos da Carne/toxicidade , Camundongos , Camundongos Endogâmicos ICR , Salsola/metabolismo , Salsola/toxicidade , Sódio/metabolismo , Sódio/toxicidade , Suínos
4.
Carbohydr Polym ; 227: 115331, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590878

RESUMO

Chitosan in both native and degraded form (oligosaccharides) acts as a growth promoter and generate responses associated with both primary and secondary metabolism in plants. Chitosan and its oligosaccharides enhance photosynthesis by amplifying the activities of various enzymes of carbon and nitrogen metabolism as well as light and dark reaction of photosynthesis. They play a vital role in stimulating photosynthetic machinery by regulating primary photochemistry. They also overcome the limitations of stomata and amplify the carbon fixation efficiency in dark reactions and promote carbohydrate synthesis. Chitosan and its oligosaccharides stimulate the enzymes and content of secondary metabolites. A plausible explanation is that chitosan and its oligosaccharides acted as the suitable ligand for the induction of available receptors and thus elicit various signaling pathways viz, GPCR and PLC/PKC, MAPK, H2O2 burst, stimulation of transcription factors in the plant generating a maximum possible response. Chitosan and its oligosaccharides also exhibit antimicrobial activities and act as biopestiside, preventing proliferation of pathogens and preserve crop yield and quality.


Assuntos
Quitosana/metabolismo , Produção Agrícola , Oligossacarídeos/metabolismo , Plantas/metabolismo , Metabolismo Secundário
5.
Carbohydr Polym ; 229: 115435, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826424

RESUMO

Micelles are one of the most investigated nanocarriers for drug delivery. In this study, polymeric micelles based on chitosan were prepared to explore the delivery mechanism which was critical for enhancing tumor targeting but still remain elusive. The chitosan polymer COSA was synthesized and the polymeric micelles showed good self-assembly ability, good dispersion stability and low toxicity. After being intravenously administered, the micelles were selectively taken up by circulating monocytes in a receptor-mediated way (almost 94% uptake in Ly-6Chi monocytes, below 7% in all other circulating cells) and reach the tumor with the subsequent travel of these cells. In addition, the micelles in macrophages (differentiated from circulating monocytes) can be exocytosed and subsequently taken up by cancer cells. The delivery mechanism of COSA micelles is directional for the novel strategies to enhance tumor targeting and the micelles are promising candidates for diseases in which monocytes are directly implicated.


Assuntos
Quitosana/metabolismo , Portadores de Fármacos/metabolismo , Micelas , Monócitos/metabolismo , Animais , Antineoplásicos/farmacologia , Doxorrubicina/farmacologia , Liberação Controlada de Fármacos , Endocitose , Exocitose , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Neoplasias/metabolismo , Células RAW 264.7
6.
Carbohydr Polym ; 229: 115437, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826460

RESUMO

Chitosan nanosystems have been widely explored to deliver therapeutic into cells. The cationic nature of the polymer facilitates its entry into the cell via the negatively charged lipid bilayer. Though the interaction is feasible for successful payload delivery, very little is known about the mechanistic aspects and kinetics of interaction of chitosan nanoparticles (Chnps) with the cellular bilayer membrane. Moreover, the precise mechanism of delivery of therapeutic agents by the Chnps is unknown. The polymerbilayer membrane is anticipated to play a crucial role in deciding its ultimate intracellular fate, while delivering its therapeutic payload. Here, we have made an attempt to understand the interaction of Chnps with the cellular membrane for delivering payload, through experimental analysis and predictive mathematical modeling. We observed that the positively charged, mucoadhesive Chnps lack specificity towards a particular cell type, but are rather successful in the intracellular delivery of nucleic acids.


Assuntos
Quitosana/metabolismo , Portadores de Fármacos/metabolismo , Nanopartículas/metabolismo , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Quitosana/química , Portadores de Fármacos/química , Endocitose/fisiologia , Fluoresceína-5-Isotiocianato/química , Corantes Fluorescentes/química , Humanos , Cinética , Lisossomos/metabolismo , Fluidez de Membrana , Modelos Biológicos , Nanopartículas/química
7.
J Pharm Biomed Anal ; 177: 112852, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31499432

RESUMO

The effect of insertion of SH and S-protected groups on the binding and mucoadhesion properties of quaternary ammonium-chitosans and their nanoparticulate forms has been investigated by NMR spectroscopy. Diclofenac sodium salt has been assumed as low molecular weight probe to detect the different binding behaviour of polymeric materials; mucin from bovine submaxillary glands was selected as the model protein for differentiating their mucoadhesion. NMR proton selective relaxation rates of the probe molecule were remarkably sensitive to the presence of very low amounts of sulfurated moieties. Impact of supramolecular aggregation in nanostructured species was demonstrated as well as the relevance of S-protection.


Assuntos
Diclofenaco/administração & dosagem , Portadores de Fármacos/química , Membrana Mucosa/metabolismo , Nanopartículas/química , Adesividade , Animais , Bovinos , Quitosana/química , Quitosana/metabolismo , Portadores de Fármacos/metabolismo , Peso Molecular , Mucinas/metabolismo , Nanopartículas/metabolismo , Espectroscopia de Prótons por Ressonância Magnética , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/metabolismo , Enxofre/química
8.
mBio ; 10(6)2019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-31848271

RESUMO

Cryptococcus neoformans can cause fatal meningoencephalitis in patients with AIDS or other immunocompromising conditions. Current antifungals are suboptimal to treat this disease; therefore, novel targets and new therapies are needed. Previously, we have shown that chitosan is a critical component of the cryptococcal cell wall and is required for survival in the mammalian host and that chitosan deficiency results in rapid clearance from the mammalian host. We had also identified several specific proteins that were required for chitosan biosynthesis, and we hypothesize that screening for compounds that inhibit chitosan biosynthesis would identify additional genes/proteins that influence chitosan biosynthesis. To identify these compounds, we developed a robust and novel cell-based flow cytometry screening method to identify small-molecule inhibitors of chitosan production. We screened the ICCB Known Bioactives library and identified 8 compounds that reduced chitosan in C. neoformans We used flow cytometry-based counterscreens and confirmatory screens, followed by a biochemical secondary screen to refine our primary screening hits to 2 confirmed hits. One of the confirmed hits that reduced chitosan content was the aminoalkylindole BML-190, a known inverse agonist of mammalian cannabinoid receptors. We demonstrated that BML-190 likely targets the C. neoformans G-protein-coupled receptor Gpr4 and, via the cyclic AMP (cAMP)/protein kinase A (PKA) signaling pathway, contributes to an intracellular accumulation of cAMP that results in decreased chitosan. Our discovery suggests that this approach could be used to identify additional compounds and pathways that reduce chitosan biosynthesis and could lead to potential novel therapeutics against C. neoformans IMPORTANCE Cryptococcus neoformans is a fungal pathogen that kills ∼200,000 people every year. The cell wall is an essential organelle that protects fungi from the environment. Chitosan, the deacetylated form of chitin, has been shown to be an essential component of the cryptococcal cell wall during infection of a mammalian host. In this study, we screened a set of 480 compounds, which are known to have defined biological activities, for activity that reduced chitosan production in C. neoformans Two of these compounds were confirmed using an alternative method of measuring chitosan, and one of these was demonstrated to impact the cAMP signal transduction pathway. This work demonstrates that the cAMP pathway regulates chitosan biosynthesis in C. neoformans and validates that this screening approach could be used to find potential antifungal agents.


Assuntos
Quitosana/metabolismo , Cryptococcus neoformans/efeitos dos fármacos , Cryptococcus neoformans/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , AMP Cíclico/metabolismo , Indometacina/análogos & derivados , Modelos Biológicos , Morfolinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Fenômenos Químicos , Descoberta de Drogas , Indometacina/química , Indometacina/farmacologia , Estrutura Molecular , Morfolinas/química , Receptores Acoplados a Proteínas-G/metabolismo
9.
mSphere ; 4(5)2019 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-31597720

RESUMO

Cryptococcus gattii R265 is a hypervirulent fungal strain responsible for the recent outbreak of cryptococcosis in Vancouver Island of British Columbia in Canada. It differs significantly from Cryptococcus neoformans in its natural environment, its preferred site in the mammalian host, and its pathogenesis. Our previous studies of C. neoformans have shown that the presence of chitosan, the deacetylated form of chitin, in the cell wall attenuates inflammatory responses in the host, while its absence induces robust immune responses, which in turn facilitate clearance of the fungus and induces a protective response. The results of the present investigation reveal that the cell wall of C. gattii R265 contains a two- to threefold larger amount of chitosan than that of C. neoformans The genes responsible for the biosynthesis of chitosan are highly conserved in the R265 genome; the roles of the three chitin deacetylases (CDAs) have, however, been modified. To deduce their roles, single and double CDA deletion strains and a triple CDA deletion strain were constructed in a R265 background and were subjected to mammalian infection studies. Unlike C. neoformans where Cda1 has a discernible role in fungal pathogenesis, in strain R265, Cda3 is critical for virulence. Deletion of either CDA3 alone or in combination with another CDA (cda1Δ3Δ or cda2Δ3Δ) or both (cda1Δ2Δ3Δ) rendered the fungus avirulent and cleared from the infected host. Moreover, the cda1Δ2Δ3Δ strain of R265 induced a protective response to a subsequent infection with R265. These studies begin to illuminate the regulation of chitosan biosynthesis of C. gattii and its subsequent effect on fungal virulence.IMPORTANCE The fungal cell wall is an essential organelle whose components provide the first line of defense against host-induced antifungal activity. Chitosan is one of the carbohydrate polymers in the cell wall that significantly affects the outcome of host-pathogen interaction. Chitosan-deficient strains are avirulent, implicating chitosan as a critical virulence factor. C. gattii R265 is an important fungal pathogen of concern due to its ability to cause infections in individuals with no apparent immune dysfunction and an increasing geographical distribution. Characterization of the fungal cell wall and understanding the contribution of individual molecules of the cell wall matrix to fungal pathogenesis offer new therapeutic avenues for intervention. In this report, we show that the C. gattii R265 strain has evolved alternate regulation of chitosan biosynthesis under both laboratory growth conditions and during mammalian infection compared to that of C. neoformans.


Assuntos
Amidoidrolases/genética , Quitosana/metabolismo , Cryptococcus gattii/metabolismo , Cryptococcus gattii/patogenicidade , Proteínas Fúngicas/genética , Amidoidrolases/metabolismo , Animais , Parede Celular/química , Parede Celular/imunologia , Criptococose/microbiologia , Cryptococcus gattii/genética , Feminino , Proteínas Fúngicas/metabolismo , Deleção de Genes , Regulação Fúngica da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Virulência , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
10.
AAPS PharmSciTech ; 20(7): 299, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31482286

RESUMO

The integrity of the nasal epithelium plays a crucial role in the airway defence mechanism. The nasal epithelium may be injured as a result of a large number of factors leading to nose bleeds, also known as epistaxis. However, local measures commonly used to treat epistaxis and improve wound healing present several side effects and patient discomfort. Hence, this study aims to address some of these drawbacks by developing a new formulation for nasal epithelial wound healing. Chitosan, a biodegradable and biocompatible polymer, was used to develop a thermosensitive nasal formulation for the delivery of tranexamic acid (TXA), one of the most effective pharmacological options to control bleeding with cost and tolerability advantages. The in situ gelation properties of the formulation upon administration in the nasal cavity were investigated in terms of gelation time and temperature. It was found that the developed formulation can undergo rapid liquid-to-gel phase change within approximately 5 min at 32°C, which is well within the human nasal cavity temperature range. The spray pattern, deposition and droplet size generated by the nasal spray was also characterised and were found to be suitable for nasal drug delivery. It was also observed that the in situ gelation of the formulation prevent nasal runoff, while the majority of drug deposited mainly in the anterior part of the nose with no lung deposition. The developed formulation was shown to be safe on human nasal epithelium and demonstrated six times faster wound closure compared to the control TXA solution.


Assuntos
Quitosana/administração & dosagem , Modelos Biológicos , Sprays Nasais , Ácido Tranexâmico/administração & dosagem , Cicatrização/efeitos dos fármacos , Administração Intranasal , Quitosana/química , Quitosana/metabolismo , Sistemas de Liberação de Medicamentos/métodos , Géis , Humanos , Mucosa Nasal/efeitos dos fármacos , Mucosa Nasal/patologia , Temperatura , Ácido Tranexâmico/química , Ácido Tranexâmico/metabolismo , Cicatrização/fisiologia
11.
Carbohydr Polym ; 223: 115094, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31426998

RESUMO

This research attempted to inspect the contribution of lactic acid bacteria (LAB) with nanoparticle application in antimicrobial enhancement. Seven lactic acid cultures-free supernatants (CFSs) in both free and nanoparticles-loaded states were examined against seven foodborne microorganisms. Lactobacillus helveticus followed by Lactobacillus Plantarum possessed considerable antimicrobial activity. Headspace GC-MS characterization of Lactobacillus helveticus CFS identified a mixture of antimicrobial and health-promoting compounds. Minimal inhibitory concentration (MIC) values for tested Gram-positive bacteria represented 50% of that for Gram-negative bacteria, 20% and 7.35% of those for fungus and yeast respectively. Nanoparticles were prepared through chitosan-tripolyphosphate nanoparticle formation giving nanospheres from in the range from 5 to 10 nm, and narrow size distribution. CFS-loaded chitosan nanoparticles (CS-NPs) significantly enhanced the overall inhibition zone diameter, as well as, the decline in MIC values for Salmonella enterica (50%) and Penicillium chrysogenum (12.5%) was observed. Lactobacillus helveticus CFS, however, displayed lower antimicrobial activity vs. nisin and natamycin, it has both antibacterial and antifungal promising activities.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Queijo/microbiologia , Quitosana/análogos & derivados , Contaminação de Alimentos/prevenção & controle , Nanopartículas/metabolismo , Antibacterianos/química , Antibacterianos/metabolismo , Antifúngicos/química , Antifúngicos/metabolismo , Quitosana/química , Quitosana/metabolismo , Quitosana/farmacologia , Relação Dose-Resposta a Droga , Egito , Fermentação , Lactobacillus helveticus/efeitos dos fármacos , Lactobacillus helveticus/metabolismo , Lactobacillus plantarum/efeitos dos fármacos , Lactobacillus plantarum/metabolismo , Testes de Sensibilidade Microbiana , Nanopartículas/química , Natamicina/química , Natamicina/metabolismo , Natamicina/farmacologia , Nisina/química , Nisina/metabolismo , Nisina/farmacologia
12.
DNA Cell Biol ; 38(10): 1048-1055, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31433200

RESUMO

DNA condensed agents can improve the transfection efficiency of the cationic liposome delivery system. However, various condensed agents have distinct transfection efficiency and cellular cytotoxicity. The object of this study was to screen the optimal agents with the high transfection efficiency and low cytotoxicity from four polymer compressive materials, polyethylenimine (PEI), chitosan, poly-l-lysine (PLL), and spermidine. DNA was precompressed with these four agents and then combined to cationic liposomes. Subsequently, the entrapment and transfection efficiency of the obtained complexes were investigated. Finally, the particle sizes, cytotoxicity, and endocytosis fashion of these copolymers (Lipo-PEI, Lipo-chitosan, Lipo-PLL, and Lipo-spermidine) were examined. It was found that these four copolymers had significantly lower cytotoxicity and higher transfection efficiency (45.5%, 42.4%, 36.8%, and 47.4%, respectively) than those in the control groups. The transfection efficiency of Lipo-PEI and Lipo-spermidine copolymers were better than the other two copolymers. In 293T cells, nystatin significantly inhibited the transfection efficiency of Lipo-PEI-DNA and Lipo-spermidine-DNA (51.88% and 46.05%, respectively), which suggest that the endocytosis pathway of Lipo-spermidine and Lipo-PEI copolymers was probably caveolin dependent. Our study indicated that these dual-degradable copolymers especially liposome-spermidine copolymer could be used as the potential biocompatible gene delivery carriers.


Assuntos
Quitosana/química , Lipossomos/química , Polietilenoimina/química , Polilisina/química , Espermidina/química , Transfecção/métodos , Cátions , Caveolina 1/genética , Caveolina 1/metabolismo , Quitosana/metabolismo , Colesterol/química , Colesterol/metabolismo , Endocitose/efeitos dos fármacos , Endocitose/genética , Ácidos Graxos Monoinsaturados/química , Ácidos Graxos Monoinsaturados/metabolismo , Células HEK293 , Humanos , Lipossomos/metabolismo , Nistatina/farmacologia , Tamanho da Partícula , Plasmídeos/química , Plasmídeos/metabolismo , Polietilenoimina/metabolismo , Polilisina/metabolismo , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/metabolismo , Espermidina/metabolismo
13.
Int J Nanomedicine ; 14: 4573-4587, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31296987

RESUMO

Introduction: Engineered nanoparticles (ENPs) are one of the most widely used types of nanomaterials. Recently, ENPs have been shown to cause cellular damage by inducing ROS (reactive oxygen species) both directly and indirectly, leading to the changes in DNA methylation levels, which is an important epigenetic mechanism. In this study, we investigated the effect of ENP-induced ROS on DNA methylation. Materials and methods: Human embryonic kidney and human keratinocyte (HaCaT) cells were exposed to three different types of ENPs: gold nanoparticles, silicon nanoparticles (SiNPs), and chitosan nanoparticles (CSNPs). We then evaluated the cytotoxicity of the ENPs by measuring cell viability, morphology, cell apoptosis, cell proliferation, cell cycle distribution and ROS levels. Global DNA methylation levels was measured using 5-methylcytosine immunocytochemical staining and HPLC analysis. DNA methylation levels of the transposable elements, long interspersed element-1 (LINE-1) and Alu, were also measured using combined bisulfite restriction analysis technique. DNA methylation levels of the TEs LINE-1 and Alu were also measured using combined bisulfite restriction analysis technique. Results: We found that HaCaT cells that were exposed to SiNPs exhibited increased ROS levels, whereas HaCaT cells that were exposed to SiNPs and CSNPs experienced global and Alu hypomethylation, with no change in LINE-1 being observed in either cell line. The demethylation of Alu in HaCaT cells following exposure to SiNPs and CSNPs was prevented when the cells were pretreated with an antioxidant. Conclusion: The global DNA methylation that is observed in cells exposed to ENPs is associated with methylation of the Alu elements. However, the change in DNA methylation levels following ENP exposure is specific to particular ENP and cell types and independent of ROS, being induced indirectly through disruption of the oxidative defense process.


Assuntos
Acetilcisteína/farmacologia , Metilação de DNA/efeitos dos fármacos , Nanopartículas/química , Nanopartículas/toxicidade , Elementos Alu/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Quitosana/metabolismo , Epigênese Genética , Ouro/metabolismo , Humanos , Queratinócitos/efeitos dos fármacos , Elementos Nucleotídeos Longos e Dispersos/efeitos dos fármacos , Coroa de Proteína , Espécies Reativas de Oxigênio/metabolismo , Silício/química
14.
Plant Physiol Biochem ; 142: 202-210, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31302409

RESUMO

Activation of induced plant resistance to control pests and diseases is regaining attention in the current climate where chemical pesticides are being progressively banned. Formulations of chitosan oligomers (COS) and pectin-derived oligogalacturonides (OGA), COS-OGA, have previously been described to induce resistance against fungal diseases in different crop plants. Here, we investigated their potential and mode-of-action as preventive measures to control root-knot nematode Meloidogyne graminicola infection in rice. The results show a significant reduction in root-galling and nematode development in rice plants that were treated through foliar application with the COS-OGA formulations FytoSol® and FytoSave® 24 h before nematode inoculation. Hormone measurements, gene expression analyses, corroborated by treatments on salicylic acid (SA) and jasmonic acid (JA)-mutants indicated that the systemic COS-OGA induced defense mechanism against nematodes is not based on SA or JA activation. However, phenylalanine ammonia lyase (PAL) gene expression in roots as well as enzymatic PAL activity in the shoots were significantly induced 24 h after foliar COS-OGA spraying in comparison with untreated plants. COS-OGA-induced systemic defense was abolished in the rice OsPAL4-mutant, demonstrating that COS-OGA-induced defense is dependent on OsPAL4 activation in rice plants.


Assuntos
Antinematódeos/farmacologia , Quitosana/metabolismo , Oryza/parasitologia , Doenças das Plantas/parasitologia , Raízes de Plantas/parasitologia , Tumores de Planta/parasitologia , Tylenchoidea , Animais , Oryza/metabolismo , Fenóis/metabolismo , Doenças das Plantas/prevenção & controle , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/metabolismo , Propanóis/metabolismo
15.
Carbohydr Polym ; 216: 332-342, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31047074

RESUMO

Chitosan has received a lot of attention as a carrier for small interfering RNA (siRNA), due to its capacity for complexation and intracellular release of these molecules. However, one of its limitations is its insolubility at neutral pH and the tendency towards aggregation of its nanoparticles in isotonic ionic strength. In this study, a series of amphipathic chitosans were synthesized by varying the degree of acetylation (DA) from ˜2 to ˜30 mol% and the degree of substitution (DS) from 5 to 25%. by tertiary amino groups (DEAE) The results showed that the adjustment of these parameters decreases the interparticle interactions mediated by hydrogen bonding to obtain nanoparticles with improved colloidal stability. siRNA-containing nanoparticles of 100 to 150 nm with low polydispersities (0.15-0.2) and slightly positive zeta potentials (˜+ 5 mV) were resistant to aggregation at pH 7.4 and ionic strength of 150 mM. This resistance to aggregation is provided by changes on the nanoparticle surface and highlights the importance of more organized self-assembly in providing colloidal stability at physiological conditions. Additionally, the PEGylation of the most promising vectors conferred favorable physicochemical properties to nanoparticles. The chitosans and their nanoparticles exhibited low toxicity and an efficient cell uptake, as probed by confocal microscopy of rhodamine labeled vectors. The results provide a new approach to overcome the limited stability of chitosan nanoparticles at physiological conditions and show the potential of these amphipathic chitosans as siRNA carriers.


Assuntos
Quitosana/análogos & derivados , Portadores de Fármacos/química , Nanopartículas/química , RNA Interferente Pequeno/administração & dosagem , Tensoativos/química , Anidridos Acéticos/química , Acetilação , Animais , Quitosana/síntese química , Quitosana/metabolismo , Quitosana/toxicidade , Dietilaminas/química , Portadores de Fármacos/síntese química , Portadores de Fármacos/metabolismo , Portadores de Fármacos/toxicidade , Fluorescência , Corantes Fluorescentes/química , Concentração de Íons de Hidrogênio , Camundongos , Nanopartículas/metabolismo , Nanopartículas/toxicidade , Tamanho da Partícula , Polietilenoglicóis/síntese química , Polietilenoglicóis/química , Polietilenoglicóis/metabolismo , Polietilenoglicóis/toxicidade , Células RAW 264.7 , RNA Interferente Pequeno/química , Rodaminas/química , Tensoativos/síntese química , Tensoativos/metabolismo , Tensoativos/toxicidade
16.
J Orthop Surg Res ; 14(1): 162, 2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-31142377

RESUMO

BACKGROUND: Polymethylmethacrylate bone cement has a variety of applications in orthopedic surgery, but it also has some shortcomings such as high heat generation during polymerization and poor integration with bone tissue. In this study, a bio-composite bone cement composed of tri-calcium phosphate and chitosan as additives to acrylic bone cement was developed. Our hypothesis is that this new bio-composite bone cement has a better osteo-integration than pure polymethyl methacrylate cement. METHODS: Physiological composition, i.e., 65 wt% inorganic and 35 wt% organic components, of tri-calcium phosphate and chitosan contents was selected as degradable additives to replace acrylic bone cement. A series of properties such as exothermic temperature changes, setting time, bio-mechanical characteristics, degradation behaviors, and in vitro cytotoxicity were examined. Preliminary in vivo animal study was also performed. RESULTS: The results showed that the bio-composite bone cement exhibited lower curing temperature, longer setting time, higher weight loss and porosity after degradation, lower compressive Young's modulus, and ultimate compressive strength as compared with those of pure polymethyl methacrylate cement. Cell proliferation tests demonstrated that the bio-composite bone cement was non-cytotoxic, and the in vivo tests revealed that was more osteo-conductive. CONCLUSIONS: The results indicated that the modified chitosan/tri-calcium phosphate/polymethyl methacrylate bio-composites bone cement could be degraded gradually and create rougher surfaces that would be beneficial to cell adherence and growth. This new bio-composite bone cement has potential in clinical application. Our future studies will focus on long-term implantation to investigate the stability of the bio-composite bone cement in long-term implantation.


Assuntos
Materiais Biocompatíveis/administração & dosagem , Cimentos para Ossos/farmacologia , Osso e Ossos/efeitos dos fármacos , Fosfatos de Cálcio/administração & dosagem , Quitosana/administração & dosagem , Animais , Materiais Biocompatíveis/metabolismo , Cimentos para Ossos/metabolismo , Osso e Ossos/metabolismo , Fosfatos de Cálcio/metabolismo , Linhagem Celular , Quitosana/metabolismo , Força Compressiva/efeitos dos fármacos , Força Compressiva/fisiologia , Teste de Materiais/métodos , Camundongos , Ratos , Ratos Sprague-Dawley
17.
Mar Drugs ; 17(4)2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30974812

RESUMO

Chitosanase has attracted great attention due to its potential applications in medicine, agriculture, and nutraceuticals. In this study, P. mucilaginosus TKU032, a bacterial strain isolated from Taiwanese soil, exhibited the highest chitosanase activity (0.53 U/mL) on medium containing shrimp heads as the sole carbon and nitrogen (C/N) source. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, a chitosanase isolated from P. mucilaginosus TKU032 cultured on shrimp head medium was determined at approximately 59 kDa. The characterized chitosanase showed interesting properties with optimal temperature and thermal stability up to 70 °C. Three chitosan oligosaccharide (COS) fractions were isolated from hydrolyzed colloidal chitosan that was catalyzed by TKU032 chitosanase. Of these, fraction I showed the highest α-glucosidase inhibitor (aGI) activity (65.86% at 20 mg/mL); its inhibitory mechanism followed the mixed noncompetitive inhibition model. Fractions II and III exhibited strong 2,2-diphenyl1-picrylhydrazyl (DPPH) radical scavenging activity (79.00% at 12 mg/mL and 73.29% at 16 mg/mL, respectively). In summary, the COS fractions obtained by hydrolyzing colloidal chitosan with TKU032 chitosanase may have potential use in medical or nutraceutical fields due to their aGI and antioxidant activities.


Assuntos
Proteínas de Bactérias/isolamento & purificação , Fatores Biológicos/biossíntese , Glicosídeo Hidrolases/isolamento & purificação , Oligossacarídeos/biossíntese , Paenibacillus/metabolismo , Animais , Proteínas de Bactérias/metabolismo , Biocatálise , Fatores Biológicos/farmacologia , Quitosana/metabolismo , Crustáceos/química , Ensaios Enzimáticos/métodos , Depuradores de Radicais Livres/metabolismo , Depuradores de Radicais Livres/farmacologia , Proteínas Fúngicas/metabolismo , Inibidores de Glicosídeo Hidrolases/metabolismo , Inibidores de Glicosídeo Hidrolases/farmacologia , Glicosídeo Hidrolases/metabolismo , Temperatura Alta , Oligossacarídeos/farmacologia , Paenibacillus/isolamento & purificação , Estabilidade Proteica , Microbiologia do Solo , Especificidade por Substrato , alfa-Glucosidases/metabolismo
18.
Int J Biol Macromol ; 132: 1262-1273, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30980874

RESUMO

Cosmetics, personal care and biomedical products obtained by bio-based polymers and natural bioactive compounds are a new growing market. The ecological awareness is changing consumers' demands, causing consumers to look for more sustainable options, with a reduced environmental impact. The innovation of this work was to develop a natural polymer matrix (chitosan) entrapping antioxidant actives compounds such as annatto (Bixa Orellana L.) and vitamin C with potential application as sustainable anti-aging skin mask treatment. Films of chitosan (Ch) and reacetylated chitosan (RCh), exhibiting different degrees of acetylation (DA = 13.3 and 33.9%, respectively), were produced. The formulations of active films of chitosan (BCh) and reacetylated chitosan (BRCh) were 1% (w/w) of chitosan, 1% (w/w) of annatto powder, 5% (w/w) of vitamin C and 1% (w/w) of glycerol (as plasticizer). Reacetylated chitosan films (DA = 33.9%) presented higher water affinity than chitosan films (DA = 13.3%). The elongation of RCh and BRCh increased and the resistance decreased, as compared to Ch and BCh. The antioxidants compounds (annatto and vitamin C) of BRCh films released faster than BCh films. Thus, the BRCh films showed potential application as an anti-aging skin mask.


Assuntos
Envelhecimento/efeitos dos fármacos , Antioxidantes/química , Antioxidantes/farmacologia , Quitosana/química , Cosméticos/química , Portadores de Fármacos/química , Pele/efeitos dos fármacos , Ácido Ascórbico/química , Ácido Ascórbico/farmacologia , Bixaceae/química , Carotenoides/química , Carotenoides/farmacologia , Linhagem Celular , Quitosana/metabolismo , Cor , Portadores de Fármacos/metabolismo , Humanos , Fenômenos Mecânicos , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Solubilidade , Vapor
19.
Molecules ; 24(7)2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30939857

RESUMO

Herein, the degradation of low molecular weight chitosan (CS), with 92% degree of deacetylation (DD), and its nanoparticles (NP) has been investigated in 0.2 mg/mL lysozyme solution at 37 °C. The CS nanoparticles were prepared using glutaraldehyde crosslinking of chitosan in a water-in-oil emulsion system. The morphological characterization of CS particles was carried out using scanning electron microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques. Using attenuated total reflectance Fourier transform infrared (ATR-FTIR) and UV-VIS spectroscopy, the structural integrity of CS and its NPs in lysozyme solution were monitored. The CS powder showed characteristic FTIR bands around 1150 cm-1 associated with the glycosidic bridges (C-O-C bonds) before and after lysozyme treatment for 10 weeks, which indicated no CS degradation. The glutaraldehyde crosslinked CS NPs showed very weak bands associated with the glycosidic bonds in lysozyme solution. Interestingly, the UV-VIS spectroscopic data showed some degradation of CS NPs in lysozyme solution. The results of this study indicate that CS with a high DD and its NPs crosslinked with glutaraldehyde were not degradable in lysozyme solution and thus unsuitable for pulmonary drug delivery. Further studies are warranted to understand the complete degradation of CS and its NPs to ensure their application in pulmonary drug delivery.


Assuntos
Quitosana/química , Reagentes para Ligações Cruzadas/química , Sistemas de Liberação de Medicamentos , Glutaral/química , Pulmão/efeitos dos fármacos , Muramidase/metabolismo , Nanopartículas/química , Quitosana/metabolismo , Reagentes para Ligações Cruzadas/metabolismo , Glutaral/metabolismo , Humanos , Técnicas In Vitro , Nanopartículas/administração & dosagem
20.
Environ Sci Pollut Res Int ; 26(28): 28510-28523, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30929177

RESUMO

In this work, three polymer suspensions were used for coating glass beads (GB), porcelain beads (PB), and polyethylene pellets (PP) in spouted bed. Subsequently, the continuous adsorption assays of the food dye Brilliant Blue FCF in a fixed bed column were performed, which was packed with the covered particles. Also, the static adsorption assays were carried out. The adsorption equilibrium isotherms were fitted by Freundlich, Langmuir, and Temkin models, being that the Temkin model was the most suitable to represent the equilibrium data. The particle coating in the spouted bed showed promising results due to the high efficiency of the process. The PB, GB, and PP obtained coating efficiency values in the range to 92-96% when using the suspension of chitosan and hydroxyethyl cellulose. However, only the polyethylene particles coated with the chitosan suspension maintained its coating efficiency (95%). The maximum adsorption capacities at equilibrium of the coated particles of PP and GB were achieved with the chitosan suspension, being the values of around 800 mg g-1. Thus, the chitosan-coated polyethylene particles showed to be a promising adsorbent for fixed bed column. Graphical abstract.


Assuntos
Quitosana/metabolismo , Corantes/química , Polímeros/química , Adsorção , Quitosana/química , Cinética
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