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1.
Chinese Journal of Biotechnology ; (12): 1655-1669, 2023.
Article in Chinese | WPRIM | ID: wpr-981161

ABSTRACT

Deacetylation of chitin is closely related to insect development and metamorphosis. Chitin deacetylase (CDA) is a key enzyme in the process. However, to date, the CDAs of Bombyx mori (BmCDAs), which is a model Lepidopteran insect, were not well studied. In order to better understand the role of BmCDAs in the metamorphosis and development of silkworm, the BmCDA2 which is highly expressed in epidermis was selected to study by bioinformatics methods, protein expression purification and immunofluorescence localization. The results showed that the two mRNA splicing forms of BmCDA2, namely BmCDA2a and BmCDA2b, were highly expressed in the larval and pupal epidermis, respectively. Both genes had chitin deacetylase catalytic domain, chitin binding domain and low density lipoprotein receptor domain. Western blot showed that the BmCDA2 protein was mainly expressed in the epidermis. Moreover, fluorescence immunolocalization showed that BmCDA2 protein gradually increased and accumulated with the formation of larval new epidermis, suggesting that BmCDA2 may be involved in the formation or assembly of larval new epidermis. The results increased our understandings to the biological functions of BmCDAs, and may facilitate the CDA study of other insects.


Subject(s)
Animals , Bombyx/metabolism , Metamorphosis, Biological/genetics , Larva/metabolism , Gene Expression , Insect Proteins/metabolism , Chitin
2.
Chinese Journal of Biotechnology ; (12): 912-929, 2023.
Article in Chinese | WPRIM | ID: wpr-970413

ABSTRACT

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.


Subject(s)
Chitosan/chemistry , Chitin , Glycoside Hydrolases/genetics , Protein Engineering , Oligosaccharides/chemistry , Hydrolysis
3.
Chinese Journal of Biotechnology ; (12): 4135-4149, 2023.
Article in Chinese | WPRIM | ID: wpr-1008017

ABSTRACT

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.


Subject(s)
Humans , Spirulina , Anti-Bacterial Agents/chemistry , Chitosan/pharmacology , Biofilms , Chitin/pharmacology
4.
Braz. j. biol ; 83: 1-8, 2023. ilus, graf, tab
Article in English | LILACS, VETINDEX | ID: biblio-1468881

ABSTRACT

Chitin and its derived products have immense economic value due to their vital role in various biological activities as well as biomedical and industrial application. Insects, microorganism and crustaceans are the main supply of chitin but the crustaceans shell like shrimp, krill, lobsters and crabs are the main commercial sources. Chitin content of an individual varies depending on the structures possessing the polymer and the species. In this study edible crabs’ shells (Callinectes sapidus) were demineralized and deproteinized resulting in 13.8% (dry weight) chitin recovery from chitin wastes. FTIR and XRD analyses of the experimental crude as well as purified chitins revealed that both were much comparable to the commercially purchased controls. The acid pretreatment ceded 54g of colloidal chitin that resulted in 1080% of the crude chitin. The colloidal chitin was exploited for isolation of eighty five chitinolytic bacterial isolates from different sources. Zone of clearance was displayed by the thirty five isolates (41.17%) succeeding their growth at pH 7 on colloidal chitin agar medium. Maximum chitinolytic activity i.e. 301.55 U/ml was exhibited by isolate JF70 when cultivated in extracted chitin containing both carbon and nitrogen. The study showed wastes of blue crabs can be utilized for extraction of chitin and isolation of chitinolytic bacteria that can be used to degrade chitin waste, resolve environmental pollution as well as industrial purpose.


A quitina e seus produtos derivados têm imenso valor econômico devido ao seu papel vital em várias atividades biológicas, bem como em aplicações biomédicas e industriais. Insetos, microrganismos e crustáceos são o principal suprimento de quitina, mas a casca dos crustáceos como camarão, krill, lagosta e caranguejo são as principais fontes comerciais. O conteúdo de quitina de um indivíduo varia dependendo das estruturas que possuem o polímero e da espécie. Neste estudo, as cascas de caranguejos comestíveis (Callinectes sapidus) foram desmineralizadas e desproteinizadas, resultando em 13,8% (peso seco) de recuperação de quitina a partir de resíduos de quitina. As análises de FTIR e XRD do bruto experimental, bem como das quitinas purificadas, revelaram que ambas eram muito comparáveis aos controles adquiridos comercialmente. O pré-tratamento com ácido cedeu 54 g de quitina coloidal que resultou em 1.080% da quitina bruta. A quitina coloidal foi analisada para isolamento de 85 isolados bacterianos quitinolíticos de diferentes fontes. A zona de eliminação foi exibida pelos 35 isolados (41,17%) que sucederam seu crescimento a pH 7 em meio de ágar de quitina coloidal. A atividade quitinolítica máxima, ou seja, 301,55 U / ml, foi exibida pelo isolado JF70 quando cultivado em quitina extraída contendo carbono e nitrogênio. O estudo mostrou que resíduos de caranguejos azuis podem ser utilizados para extração de quitina e isolamento de bactérias quitinolíticas que podem ser usadas para degradar resíduos de quitina, resolver a poluição ambiental e também para fins industriais.


Subject(s)
Chitin/analysis , Chitin/economics , Chitin/isolation & purification , Chitinases
5.
Arq. Ciênc. Vet. Zool. UNIPAR (Online) ; 25(2): e6378, jul-dez. 2022.
Article in Portuguese | LILACS, VETINDEX | ID: biblio-1399609

ABSTRACT

Os resíduos provenientes da aquicultura são derivados da ração e da excreção dos peixes e podem estar sedimentados, suspensos ou dissolvidos, ocasionando elevados valores de DBO, DQO, nitrogênio e fósforo. A produção de camarões no Brasil tem gerado elevadas quantidades de resíduos sólidos, tendo em vista que os exoesqueletos dos camarões correspondem a cerca de 40% do seu peso total, resultando num forte impacto ambiental. Diversas pesquisas envolvendo a quitina estão sendo desenvolvidas na área de tratamento de água, devido principalmente a sua capacidade de formar filme, sendo utilizada em sistemas filtrantes. Este polissacarídeo também pode ser utilizado como agente floculante no tratamento de efluentes, como adsorvente na clarificação de óleos, e principalmente na produção de quitosana. Atualmente a quitosana possui aplicações multidimensionais, desde áreas como a nutrição humana, biotecnologia, ciência dos materiais, indústria farmacêutica, agricultura, terapia genética e proteção ambiental. A quitosana é muito eficiente na remoção de poluentes em diferentes concentrações. Apresenta alta capacidade e grande velocidade de adsorção, boa eficiência e seletividade tanto em soluções que possuem altas ou baixas concentrações. O uso da biotecnologia, através do processo de adsorção utilizando adsorventes naturais e baratos, como a quitina e quitosana, minimiza os impactos ambientais da aquicultura tanto em relação aos provocados pelo lançamento de efluentes no meio ambiente quanto aos causados pelo descarte inadequado dos resíduos do processamento de camarões.(AU)


Aquaculture residues are derived from fish feed and excretion and may be sedimented, suspended or dissolved, resulting in high BOD, COD, nitrogen and phosphorus values. Shrimp production in Brazil has generated high amounts of solid waste, since shrimp exoskeletons account for about 40% of their total weight, resulting in a strong environmental impact. Several researches involving chitin are being developed in the area of water treatment, mainly due to its ability to form film, being used in filter systems. This polysaccharide can also be used as a flocculating agent in the treatment of effluents, as an adsorbent in the clarification of oils, and especially in the production of chitosan. Currently, chitosan has multidimensional applications, from areas such as human nutrition, biotechnology, materials science, pharmaceutical industry, agriculture, gene therapy and environmental protection. Chitosan is very efficient in the removal of pollutants at different concentrations. It presents high capacity and high adsorption velocity, good efficiency and selectivity both in solutions that have high or low concentrations. The use of biotechnology, through the adsorption process using natural and cheap adsorbents such as chitin and chitosan, minimizes the environmental impacts of aquaculture both in relation to those caused by the release of effluents into the environment and those caused by the inappropriate disposal of processing residues of shrimps.(AU)


Los residuos procedentes de la acuicultura se derivan de la ración y de la excreción de los peces y pueden estar sedimentados, suspendidos o disueltos, ocasionando elevados valores de DBO, DQO, nitrógeno y fósforo. La producción de camarones en Brasil ha generado grandes cantidades de residuos sólidos, teniendo en cuenta que los exoesqueletos de los camarones corresponden a cerca del 40% de su peso total, resultando en un fuerte impacto ambiental. Varias investigaciones involucrando la quitina se están desarrollando en el área de tratamiento de agua, debido principalmente a su capacidad de formar película, siendo utilizada en sistemas filtrantes. Este polisacárido también puede ser utilizado como agente floculante en el tratamiento de efluentes, como adsorbente en la clarificación de aceites, y principalmente en la producción de quitosana. Actualmente la quitosana posee aplicaciones multidimensionales, desde áreas como la nutrición humana, biotecnología, ciencia de los materiales, industria farmacéutica, agricultura, terapia genética y protección ambiental. La quitosana es muy eficiente en la eliminación de contaminantes en diferentes concentraciones. Presenta alta capacidad y gran velocidad de adsorción, buena eficiencia y selectividad tanto en soluciones que poseen altas o bajas concentraciones. El uso de la biotecnología, a través del proceso de adsorción utilizando adsorbentes naturales y baratos, como la quitina y quitosana, minimiza los impactos ambientales de la acuicultura tanto en relación a los provocados por el lanzamiento de efluentes en el medio ambiente en cuanto a los causados por el descarte inadecuado de los residuos del procesamiento de camarones.(AU)


Subject(s)
Chitin/administration & dosage , Adsorption/drug effects , Chitosan/administration & dosage , Wastewater/chemistry , Biopolymers/analysis , Aquaculture , Eutrophication/physiology , Ammonia/chemistry
6.
Chinese Journal of Biotechnology ; (12): 218-227, 2021.
Article in Chinese | WPRIM | ID: wpr-878556

ABSTRACT

β-N-acetylglucosaminidases (NAGases) can convert natural substrates such as chitin or chitosan to N-acetyl-β-D glucosamine (GlcNAc) monomer that is wildly used in medicine and agriculture. In this study, the BcNagZ gene from Bacillus coagulans DMS1 was cloned and expressed in Escherichia coli. The recombinant protein was secreted into the fermentation supernatant and the expression amount reached 0.76 mg/mL. The molecular mass of purified enzyme was 61.3 kDa, and the specific activity was 5.918 U/mg. The optimal temperature and pH of the BcNagZ were 75 °C and 5.5, respectively, and remained more than 85% residual activity after 30 min at 65 °C. The Mie constant Km was 0.23 mmol/L and the Vmax was 0.043 1 mmol/(L·min). The recombinant BcNagZ could hydrolyze colloidal chitin to obtain trace amounts of GlcNAc, and hydrolyze disaccharides to monosaccharide. Combining with the reported exochitinase AMcase, BcNagZ could produce GlcNAc from hydrolysis of colloidal chitin with a yield over 86.93%.


Subject(s)
Acetylglucosamine , Acetylglucosaminidase , Bacillus coagulans , Chitin , Chitinases , Hydrogen-Ion Concentration , Recombinant Proteins/genetics
7.
Journal of Zhejiang University. Science. B ; (12): 611-627, 2020.
Article in English | WPRIM | ID: wpr-1010541

ABSTRACT

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.


Subject(s)
Alginic Acid/chemistry , Chitin/chemistry , Chitosan , Delayed-Action Preparations , Digestion , Drug Compounding , Drug Liberation , Gastrointestinal Tract/metabolism , Immunoglobulins/metabolism , Oligosaccharides
8.
São Paulo; s.n; s.n; 2019. 105 p. tab, graf.
Thesis in Portuguese | LILACS | ID: biblio-996861

ABSTRACT

Quitosana é um biopolímero encontrado principalmente na parede celular de crustáceos e é obtida pela desacetilação da quitina. Como biopolímero a quitosana é utilizada como excipiente para medicamentos e composição de alimentos. No entanto a quitosana devidamente purificada para uso farmacêutico ou alimentício tem custo financeiro elevado. Outro fator que contribui para o uso limitado é a falta de procedimento padronizado para desacetilação, o que resulta em materiais com diferentes graus de qualidade, dificultando suas aplicações e controle de qualidade de matéria prima e produto. Este trabalho tem como principal objetivo estabelecer procedimento reprodutível para a extração da quitina e da quitosana, por meio da aplicação dos conceitos de Quality by Design e planejamento de experimentos. A quitosana foi obtida pela desacetilação da quitina de crustáceos pelas etapas de desmineralização, desproteinização e despigmentação. O procedimento técnico para purificação da quitosana foi definido a partir de planejamento fatorial com ponto central para as etapas otimizadas, por meio da aplicação dos conceitos de Quality by Design e planejamento de experimentos. O projeto definiu um procedimento padronizado para purificação da quitosana que pode ser empregado em escala industrial, e financeiramente vantajoso para produção de medicamentos ou alimentos


Chitosan is a biopolymer found mainly in the cell wall of crustaceans and is obtained by the deacetylation of chitin. As biopolymer chitosan is used as excipient for medicaments and food composition. However, chitosan duly purified for pharmaceutical or food use has a high financial cost. Another factor that contributes to the limited use is the lack of standardized procedure for deacetylation, which results in materials with different grades of quality, hindering their applications and quality control of raw material and product. This work has as main objective to establish a reproducible procedure for the extraction of chitin and chitosan, through the application of the concepts of Quality by Design and planning of experiments. Chitosan was obtained by the deacetylation of chitin from crustaceans through the demineralization, deproteinization and depigmentation stages. The technical procedure for purification of chitosan was defined from a factorial planning with a central point for the optimized steps, through the application of the concepts of Quality by Design and planning of experiments. The project defined a standard procedure for the purification of chitosan that can be used on industrial scale and financially advantageous for the production of medicines or foods


Subject(s)
Pharmaceutical Preparations/classification , Chitosan/isolation & purification , Chitosan/analysis , Process Optimization , Food/classification , Chitin/isolation & purification
9.
Chinese Journal of Biotechnology ; (12): 1214-1221, 2019.
Article in Chinese | WPRIM | ID: wpr-771807

ABSTRACT

Yeast cell wall plays an important role in the establishment and maintenance of cell morphology upon the cell wall stress. The cell wall of yeast consists of β-glucans, mannoproteins and chitin. The composition and structure remodel due to cell wall stress. Brewer's yeast cell wall exhibits stress response during long-term acclimation in order to adapt to environmental changes. This paper reviews the composition and structure of yeast cell wall and the molecular mechanisms of cell wall remodeling and signal pathway regulation.


Subject(s)
Cell Wall , Chitin , Saccharomyces cerevisiae
10.
Chinese Journal of Biotechnology ; (12): 1787-1796, 2019.
Article in Chinese | WPRIM | ID: wpr-771753

ABSTRACT

Chitinase has a wide industrial application prospect. For example, it can degrade shrimp shells, crab shells and other crustacean waste into high value-added chitooligosaccharides. However, the low catalytic efficiency of chitinase greatly limits the production of chitooligosaccharides. In previous study, the we expressed a chitinase Chisb with high catalytic efficiency and studied its enzymatic properties. In order to further improve the catalytic efficiency of Chisb, with R13NprB-C-SP-H as the parent, here error-prone PCR was used to construct random mutant library to conduct directed evolution of chitinase Chisb. Two mutants C43D and E336R were obtained with 96-well plate primary screening and shaker-screening, and their enzymatic properties were also studied. The optimum temperature of C43D and E336R was 55 °C, and the optimum pH of C43D was 5.0, while that of E336R was 9.0. The catalytic efficiency of C43D and E336R was 1.35 times and 1.57 times higher than that of control. The chitooligosaccharide concentration of E336R and C43D was 2.53 g/L and 2.06 g/L, improved by 2.84 times and 2.31 times compared with the control (0.89 g/L), respectively. In addition, the substrate conversion rate of mutants E336R and C43D was 84.3% and 68.7%, improved by 54.6% and 39% compared with the control (29.7%), respectively. In summary, the study indicates that random mutation introduced by error-prone PCR can effectively improve the catalytic efficiency of chitinase Chisb. The positive mutants with higher catalytic efficiency obtained in the above study and their enzymatic property analysis have important research significance and application value for the biosynthesis of chitooligosaccharides.


Subject(s)
Biocatalysis , Chitin , Chitinases , Hydrogen-Ion Concentration , Polymerase Chain Reaction
11.
Arq. Inst. Biol ; 86: e0982018, 2019. tab
Article in English | LILACS, VETINDEX | ID: biblio-1024594

ABSTRACT

In this study, chitin and chitosan were extracted from Litopenaeus vannamei waste using chemical and microwave methods. Shrimp waste was cleaned, dried and ground sieved to 16, 32 and 60 mesh, and the samples were depigmented, demineralized, and deproteinized. Then, the chitin was submitted to a deacetylation process by 45% NaOH solution under microwave irradiation at 600w, for intermittent 15 min or using 5 pulses of 5 minutes. The study showed that the effectiveness of the particle size of 32 mesh and 6 pulses of 5 min to deacetylation with 92% of degree and chitosan yield (52.2%). The polymer chitosan showed higher antimicrobial activity against to Staphylococcus aureus, Escherichia coli, Salmonella enterica and the yeast Candida sp., respectively. The results indicated the feasibility of the microwave radiation as an attractive method to recover chitin and chitosan from shrimp wastes.(AU)


Neste estudo, a quitina e a quitosana foram extraídas de resíduos de Litopenaeus vannamei utilizando métodos químicos e do micro-ondas. Os resíduos de camarão foram limpos, secos e peneirados a 16, 32 e 60 mesh, e as amostras foram despigmentadas, desmineralizadas e desproteinizadas. Posteriormente, a quitina foi submetida a processo de desacetilação por solução de NaOH a 45% sob irradiação de micro-ondas a 600w, durante 15 min intermitentes ou utilizando 6 pulsos de 5 min. O estudo mostrou eficácia nas partículas com tamanho de 32 mesh e 6 pulsos de 5 minutos, com 92% grau de desacetilação e rendimento de quitosana (52,2%). A atividade antimicrobiana foi para Staphylococcus aureus, Escherichia coli e Salmonella enterica contra a levedura Candida sp., respectivamente. Os resultados indicaram a viabilidade da radiação de micro-ondas como um método atraente para recuperação de quitina e quitosana a partir de resíduos de camarão.(AU)


Subject(s)
Chitin , Penaeidae , Chitosan , Anti-Bacterial Agents , Staphylococcus aureus , Salmonella enterica , Escherichia coli , Antifungal Agents
12.
The Korean Journal of Parasitology ; : 199-203, 2018.
Article in English | WPRIM | ID: wpr-742231

ABSTRACT

The cutaneous myiasis has been rarely reported in the Republic of Korea. We intended to describe here a case of furuncular cutaneous myiasis caused by Cordylobia anthropophaga larvae in a Korean traveler returned from Central Africa. A patient, 55-year-old man, had traveled to Equatorial Guinea, in Central Africa for a month and just returned to Korea. Physical examinations showed 2 tender erythematous nodules with small central ulceration on the left buttock and thigh. During skin biopsy, 2 larvae came out from the lesion. C. anthropophaga was identified by paired mouth hooks (toothed, spade-like, oral hooklets) and 2 posterior spiracles, which lack a distinct chitinous rim. Although rarely described in Korea until now, cutaneous myiasis may be encountered more frequently with increasing international travel and exchange workers to tropical areas.


Subject(s)
Humans , Middle Aged , Africa, Central , Biopsy , Buttocks , Chitin , Equatorial Guinea , Korea , Larva , Mouth , Myiasis , Physical Examination , Republic of Korea , Skin , Thigh , Ulcer
13.
Mycobiology ; : 129-137, 2018.
Article in English | WPRIM | ID: wpr-729787

ABSTRACT

Black rot disease in orchids is caused by the water mold Phytophthora palmivora. To gain better biocontrol performance, several factors affecting growth and antifungal substance production by Pseudomonas aeruginosa RS1 were verified. These factors include type and pH of media, temperature, and time for antifungal production. The results showed that the best conditions for P. aeruginosa RS1 to produce the active compounds was cultivating the bacteria in Luria-Bertani medium at pH 7.0 for 21 h at 37 °C. The culture filtrate was subjected to stepwise ammonium sulfate precipitation. The precipitated proteins from the 40% to 80% fraction showed antifungal activity and were further purified by column chromatography. The eluted proteins from fractions 9–10 and 33–34 had the highest antifungal activity at about 75% and 82% inhibition, respectively. SDS-PAGE revealed that the 9–10 fraction contained mixed proteins with molecular weights of 54 kDa, 32 kDa, and 20 kDa, while the 33–34 fraction contained mixed proteins with molecular weights of 40 kDa, 32 kDa, and 29 kDa. Each band of the proteins was analyzed by LC/MS to identify the protein. The result from Spectrum Modeler indicated that these proteins were closed similarly to three groups of the following proteins; catalase, chitin binding protein, and protease. Morphological study under scanning electron microscopy demonstrated that the partially purified proteins from P. aeruginosa RS1 caused abnormal growth and hypha elongation in P. palmivora. The bacteria and/or these proteins may be useful for controlling black rot disease caused by P. palmivora in orchid orchards.


Subject(s)
Ammonium Sulfate , Bacteria , Carrier Proteins , Catalase , Chitin , Chromatography , Electrophoresis, Polyacrylamide Gel , Fungi , Hydrogen-Ion Concentration , Hyphae , Microscopy, Electron, Scanning , Molecular Weight , Phytophthora , Pseudomonas aeruginosa , Pseudomonas , Water
14.
Arq. bras. med. vet. zootec. (Online) ; 69(4): 896-900, jul.-ago. 2017. ilus, tab
Article in Portuguese | LILACS, VETINDEX | ID: biblio-876681

ABSTRACT

A resistência à tração e o diâmetro são características de grande importância na avaliação da qualidade de fios de sutura, estando relacionados à capacidade destes de suportar o estresse promovido pelas forças atuantes em determinados tecidos. Desta forma, objetivou-se com este estudo avaliar as propriedades mecânica e dimensional de fios de sutura à base de quitosana, comparando-as com as preconizadas pela norma NBR 13904/2003. Tais propriedades foram avaliadas usando-se uma máquina de ensaio universal e um micrômetro digital. Os parâmetros mecânico e dimensional analisados foram a resistência quanto à tração, a deformação, bem como o diâmetro, respectivamente. O valor médio do diâmetro dos fios de quitosana apresentou variação e observou-se resistência à tração ligeiramente abaixo da norma preconizada, com rápida deformação. O fio de quitosana, na forma em que foi produzido, apresentou variabilidade dimensional e baixa resistência à tração, havendo a necessidade de melhorias no método de fabricação dele.(AU)


Tensile strength and diameter are very important characteristics in assessing the quality of suture, being related to their ability to withstand the stress caused by forces acting in certain tissues. Thus, the aim of this study was to evaluate the mechanical and dimensional properties of chitosan-based suture, comparing them with those recommended by the NBR 13904/2003. These properties were evaluated by using a universal testing machine and a digital micrometer. The mechanical and dimensional parameters analyzed were resistance to traction, deformation and diameter, respectively. The average diameter of the chitosan showed variation and yarn tensile strength was observed slightly below the recommended standard, with rapid deformation. The chitosan yarn in the form in which it was produced, presented dimensional variability and low tensile strength, there is a need for improvements in the method of manufacturing the same.(AU)


Subject(s)
Biomechanical Phenomena , Chitin , Polymers , Sutures , Tensile Strength
15.
Semina cienc. biol. saude ; 38(1): 25-34, jan./jun 2017. Tabelas
Article in Portuguese | LILACS | ID: biblio-905103

ABSTRACT

O estudo objetivou avaliar a produção de biomassa de nove isolados de Cunninghamella sp. e da cepa referência de Cunninghamella elegans (CBMAI 0843) e estabelecer a capacidade de produção de quitina e quitosana por estas cepas. Assim como, caracterizar a quitosana fúngica obtida por parâmetros como massa molar, grau de desacetilação e distribuição dos grupos funcionais ao longo da cadeia polimérica. Para a maioria das cepas avaliadas, o período de maior crescimento foi em 48 horas de cultivo, sendo que, neste período, o isolado UFT Ce08 apresentou a maior quantidade de biomassa, 20,17 g L-1. Os rendimentos de quitina ficaram entre 15,64 a 30,33% e os rendimentos de quitosana entre 0,94 a 7,43%. A cepa UFT Ce11 apresentou o melhor quantitativo de quitina e a cepa UFT Ce09, mesmo apresentando o segundo menor quantitativo de biomassa, 9,34 g L-1, teve o melhor rendimento de quitosana. Sete cepas isoladas no presente estudo apresentaram maior rendimento de quitosana comparada à cepa referência. O grau médio de desacetilação foi de 83,7% para quitosana obtida do isolado UFT Ce09 e 80,5% para quitosana obtida da cepa referência. As massas molares para a quitosana do isolado UFT Ce09 e da cepa referência foram de 43,031 e 19,215 g mol-1, respetivamente. A espectrometria de infravermelho apresentou bandas com comprimentos de onda e grupos funcionais coincidentes com a literatura e com a quitosana comercial. A quitosana fúngica deste estudo apresentou propriedades que atestam sua qualidade e características de interesse biotecnológico e comercial (AU).


The aim of this study was to evaluate the biomass production of nine Cunninghamella sp. isolates as well as by the reference strain Cunninghamella elegans (CBMAI 0843) and establish the chitin and chitosan production capacity by these strains. For most of the tested strains, the highest growth period was within 48 hours of cultivation, although the UFT Ce08 isolate showed the highest amount of biomass, with 20.17 g L-1. Chitin yields were between 15.64 to 30.33% and chitosan yields were between 0.94 to 7.43%. The UFT Ce11 strain presented the best chitin quantity and UFT Ce09 strain, even with the second smallest biomass quantity, had the best chitosan yield. This means that seven isolated strains in this study showed higher chitosan yield compared to the reference strain. The degree of deacetylation was 83.7% for the chitosan obtained from the UFT Ce09 isolate and 80.5% for the chitosan obtained from the reference strain. The chitosan molecular weight for the UFT Ce09 isolate and the reference strain were 43.031 g mol-1 and 19.215 g mol-1, respectively. The infrared spectroscopy presented bands with wavelengths and functional groups coincident to the literature and to the commercial chitosan. The fungal chitosan of this study showed properties that confirm its quality and characteristics of biotechnological and commercial interest (AU).


Subject(s)
Biomass , Biopolymers , Chitin , Chitosan , Cunninghamella
16.
Bauru; s.n; 2017. 103 p. ilus, tab, graf.
Thesis in Portuguese | LILACS, BBO | ID: biblio-880031

ABSTRACT

O desenvolvimento de biomateriais com aplicações na área da saúde mostram-se cada vez mais importantes e a procura por novos polímeros com propriedades bioativas, biodegradabilidade, atoxicidade são o foco das principais pesquisas em diferentes aplicações médicas e odontológicas. Os materiais capeadores pulpares evoluíram rapidamente na ultima década, sendo que são disponibilizadas atualmente diversas alternativas para uso clínico odontológico. Este trabalho teve como objetivo o desenvolvimento de um novo produto bioestimulador e capeador dentino/pulpar que poderá ser base para o desenvolvimento e recobrimento de scaffolds para reparo das diferentes estruturas dentárias. O desenvolvimento das bandagens BBio e os resultados obtidos nos testes das propriedades físico-químicas (absorção de água, perda de massa e pH), bem como as análises biológicas da morfologia celular e viabilidade celular com MTT a BBio apresentaram dados favoráveis e desejáveis para sua aplicação clínica. A propriedade de liberação de cálcio foi bastante promissora, sendo esta uma condição que dará a diferenciação positiva da BBio como um produto bioestimulador pulpar. Com esses dados pode-se concluir que a mesma se encontra dentro dos parâmetros desejados para o produto final e com propriedades semelhantes aos produtos existentes no mercado, de qualidade e aprovados pelas agências reguladoras.(AU)


The development of biomaterials with applications in the health area are increasingly important and the search for new polymers with bioactive properties, biodegradability and toxicity are the focus of the main researches in different medical and dental applications. The pulp capping materials evolved rapidly in the last decade, and several alternatives are now available for clinical dental use. This project aimed to develop a new biostimulating and dentin / pulp capping product that could be the basis for the development and recoating of "scaffolds" for repair of different dental structures. The development of the BBio bandages and the results obtained in the physical-chemical properties tests (water absorption, loss of mass and pH), as well as the biological analyzes of the cellular morphology and cell viability with MTT to BBio presented favorable and desirable data for its clinical application. The calcium release property was quite promising, and this is a condition that will give BBio a positive differentiation as a pulp biostimulator product. With this data it can be concluded that it is within the parameters desired for the final product and with properties similar to the products on the market, of quality and approved by the regulatory agencies.(AU)


Subject(s)
Humans , Biocompatible Materials/chemistry , Dental Pulp/drug effects , Dentin/drug effects , Pulp Capping and Pulpectomy Agents/chemistry , Analysis of Variance , Biocompatible Materials/pharmacology , Biocompatible Materials/standards , Cell Survival , Chitin/chemistry , Chitosan/chemistry , Fibroblasts/drug effects , Materials Testing , Microscopy, Electrochemical, Scanning , Pulp Capping and Pulpectomy Agents/pharmacology , Pulp Capping and Pulpectomy Agents/standards , Reproducibility of Results , Time Factors
17.
Braz. j. med. biol. res ; 50(1): e5658, 2017. tab, graf
Article in English | LILACS | ID: biblio-839234

ABSTRACT

Chitinases are hydrolases that degrade chitin, a polymer of N-acetylglucosamine linked β(1-4) present in the exoskeleton of crustaceans, insects, nematodes and fungal cell walls. A metagenome fosmid library from a wastewater-contaminated soil was functionally screened for chitinase activity leading to the isolation and identification of a chitinase gene named metachi18A. The metachi18A gene was subcloned and overexpressed in Escherichia coli BL21 and the MetaChi18A chitinase was purified by affinity chromatography as a 6xHis-tagged fusion protein. The MetaChi18A enzyme is a 92-kDa protein with a conserved active site domain of glycosyl hydrolases family 18. It hydrolyses colloidal chitin with an optimum pH of 5 and temperature of 50°C. Moreover, the enzyme retained at least 80% of its activity in the pH range from 4 to 9 and 98% at 600 mM NaCl. Thin layer chromatography analyses identified chitobiose as the main product of MetaChi18A on chitin polymers as substrate. Kinetic analysis showed inhibition of MetaChi18A activity at high concentrations of colloidal chitin and 4-methylumbelliferyl N,N′-diacetylchitobiose and sigmoid kinetics at low concentrations of colloidal chitin, indicating a possible conformational change to lead the chitin chain from the chitin-binding to the catalytic domain. The observed stability and activity of MetaChi18A over a wide range of conditions suggest that this chitinase, now characterized, may be suitable for application in the industrial processing of chitin.


Subject(s)
Chitinases/genetics , Chitin/genetics , Metagenome/genetics , Chitinases/chemistry , Chitin/chemistry , Chromatography, High Pressure Liquid , Escherichia coli , Gene Expression/genetics , Gene Library , Genetic Vectors , Hydrogen-Ion Concentration , Substrate Specificity
18.
Braz. j. microbiol ; 47(1): 25-32, Jan.-Mar. 2016. tab, graf
Article in English | LILACS | ID: lil-775113

ABSTRACT

Abstract Twelve isolates of Trichoderma spp. isolated from tobacco rhizosphere were evaluated for their ability to produce chitinase and β-1,3-glucanase extracellular hydrolytic enzymes. Isolates ThJt1 and TvHt2, out of 12 isolates, produced maximum activities of chitinase and β-1,3-glucanase, respectively. In vitro production of chitinase and β-1,3-glucanase by isolates ThJt1 and TvHt2 was tested under different cultural conditions. The enzyme activities were significantly influenced by acidic pH and the optimum temperature was 30 °C. The chitin and cell walls of Sclerotium rolfsii, as carbon sources, supported the maximum and significantly higher chitinase activity by both isolates. The chitinase activity of isolate ThJt1 was suppressed significantly by fructose (80.28%), followed by glucose (77.42%), whereas the β-1,3-glucanase activity of ThJt1 and both enzymes of isolate TvHt2 were significantly suppressed by fructose, followed by sucrose. Ammonium nitrate as nitrogen source supported the maximum activity of chitinase in both isolates, whereas urea was a poor nitrogen source. Production of both enzymes by the isolates was significantly influenced by the cultural conditions. Thus, the isolates ThJt1 and TvHt2 showed higher levels of chitinase and β-1,3-glucanase activities and were capable of hydrolyzing the mycelium of S. rolfsii infecting tobacco. These organisms can be used therefore for assessment of their synergism in biomass production and biocontrol efficacy and for their field biocontrol ability against S. rolfsii and Pythium aphanidermatum infecting tobacco.


Subject(s)
Chitinases , Soil Microbiology , Trichoderma/enzymology , Trichoderma/growth & development , Basidiomycota/metabolism , Carbon/metabolism , Cell Wall/metabolism , Chitin/metabolism , Culture Media/chemistry , Hydrogen-Ion Concentration , Nitrogen/metabolism , Rhizosphere , Temperature , Nicotiana , Trichoderma/isolation & purification
19.
Acta cir. bras ; 31(2): 119-125, Feb. 2016. graf
Article in English | LILACS | ID: lil-775562

ABSTRACT

PURPOSE: To detect whether chitin and sepia ink sponge (CS) can promote wound healing and elevate impact of CS on phagocytosis ability of macrophages. METHODS: Forty-eight rats were assigned to four groups: Normal group (Normal), negative control group (Con), chitin and sepia ink sponge group (CS) and positive control Surgicel Gauze(r) group (SG). Deep second-degree burn model was created in rats. Wound area was recorded by digital imaging and determined using Image J software. Samples were collected and kept at -80oC on 3d, 7d, 14d and 21d for cytokines detecting. Transforming growth factor (TGF)-β1, interleukin (IL)-6, matrix metalloproteinase (MMP)-1, hydroxyproline (Hyp) and macrophage activity reflected by tumor necrosis factor (TNF)-α were determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: Comparing to Con and SG, scabs in CS group fell off and basically healed on 21 day. TGF-β1, IL-6, MMP-1 and Hyp were significantly increased by CS and SG comparing to Con (p < 0.05), CS had more apparently adjustment on TGF-β1 and MMP-1 compared to SG; results in vitro indicated CS significantly promoted phagocytosis ability of macrophages reflected in TNF-α (p < 0.05). CONCLUSION: CS improved wound healing through exerting significant influences on secretion of kinds of cytokines and activating macrophages.


Subject(s)
Animals , Male , Wound Healing/drug effects , Burns, Chemical/drug therapy , Chitin/pharmacology , Sepia , Macrophages/drug effects , Phagocytosis/drug effects , Random Allocation , Chitin/therapeutic use , Cytokines/drug effects , Cytokines/metabolism , Rats, Wistar , Matrix Metalloproteinase 1/drug effects , Disease Models, Animal , Hydroxyproline/metabolism , Ink , Macrophages/metabolism
20.
Allergy, Asthma & Immunology Research ; : 362-374, 2016.
Article in English | WPRIM | ID: wpr-39535

ABSTRACT

PURPOSE: Chitin is a potent adjuvant in the development of immune response to inhaled allergens in the airways. According to other studies, chitin is known as multi-faced adjuvants which can induce Th2 responses. Recently, we found that TNF-α is a key mediator in the development of Th2 cell response to inhaled allergens. Here, we evaluated the immunologic mechanisms in the development of airway hypersensitivity to inhaled allergens, enhanced by house dust mite (HDM)-derived chitin. METHODS: The role of TNF-α and TLRs was evaluated in an airway hypersensitivity mouse model induced by a sensitization with an allergen (ovalbumin, OVA) and HDM-derived chitin using mice with the null mutation of target genes. RESULTS: The present study showed that airway sensitization with HDM-derived chitin plus OVA enhanced OVA-induced airway inflammation v. OVA alone. This phenotype was associated with the increased expression of Th1, Th2, and Th17 cytokines and also with the enhanced production of OVA-specific IgE, IgG1, and IgG2a. As for T cell responses, OVA-specific Th2 cell response, enhanced by chitin, was abolished by the treatment of chitinase, whereas Th1 and Th17 cell responses enhanced by this treatment. Moreover, the null mutation of the TNF-α gene revealed similar effects as the chitinase treatment. In contrast, all the OVA-specific T cell responses, enhanced by chitin, were blocked by the absence of TLR2, but not of TLR1, TLR4, or TLR6. CONCLUSIONS: In conclusion, these data suggest that HDM-derived chitin may enhance airway hypersensitivity to inhaled allergens, via the TLR2-dependent pathway, and that chitin-induced TNF-α can be a key mediator in the development of Th2 cell response to inhaled allergens.


Subject(s)
Animals , Mice , Allergens , Chitin , Chitinases , Cytokines , Dust , Hypersensitivity , Immunoglobulin E , Immunoglobulin G , Inflammation , Ovum , Phenotype , Pyroglyphidae , Th17 Cells , Th2 Cells
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