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"Pilado add Value": valorisation of non-traditional marine resources

Avelelas, Francisco Pires
Fonte: Instituto Politécnico de Leiria Publicador: Instituto Politécnico de Leiria
Tipo: Dissertação de Mestrado
Publicado em //2013 POR
Relevância na Pesquisa
27.77%
Dissertação para obtenção do Grau de Mestre em Biotecnologia dos Recursos Marinhos apresentada à ESTM - Escola Superior de Turismo e Tecnologia do Mar do Instituto Politécnico de Leiria.; In recent years, the valorisation of by-products resulted from fisheries discards has received much attention due to the awareness of economic and environmental negative impacts. However, the crustacean shellfish by-products contain several compounds that can be processed to yield chitin which has a myriad of industrial and biotechnological applications. The swimming crab, Polybius henslowii, despite being an extremely abundant marine resource, it is not presently subject to commercial use. Given the negative impact on the fishing nets fisherman´s see this marine resource as a plague and not as a potential source of economic incomes. Thereby, this work aims to be a contribution for the economic valorisation of Polybius henslowii as a raw material for polymer extraction, aiming for biotechnological purposes. Chitin and chitosan were extracted and produced from segmented body parts of Polybius henslowii: pereopods and carapace. Chitosan served then as raw material for the production of water-soluble chitosans (WSC) and chitooligosaccharides (COS)...

Direct detection of underivatized chitooligosaccharides produced through chitinase action using capillary zone electrophoresis

BLANES, Lucas; SAITO, Renata M.; GENTA, Fernando A.; DONEGA, Juliana; TERRA, Walter R.; FERREIRA, Clelia; LAGO, Claudimir Lucio do
Fonte: ACADEMIC PRESS INC ELSEVIER SCIENCE Publicador: ACADEMIC PRESS INC ELSEVIER SCIENCE
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
37.77%
Capillary electrophoresis with capacitively coupled contactless conductivity detection was successfully used to quantify N-acetylglucosamine and five N-acetyl-chitooligosaccharides (C2-C6) produced after reaction with a purified chitinase (TmChi) from Tenebrio molitor (Coleoptera). No derivatization process was necessary. The separation was developed using 10 mM NaOH with 10% (v/v) acetonitrile as background electrolyte and homemade equipment with a system that avoids the harmful effect of electrolysis. The limit of detection for all oligosaccharides was ca. 3 mu M, and the results indicated that the larger the oligosaccharide, the higher the sensitivity. Analysis of the chitooligosaccharides produced revealed that TmChi has an endolytic cleavage pattern with C5 as the best substrate (higher catalytic efficiency k(cat)/K-M) releasing C2 and C3. (c) 2007 Elsevier Inc. All rights reserved.

Inovações instrumentais em sistemas de eletroforese capilar com detecção eletroquímica e aplicações em análises de mono e oligossacarídeos, aminoácidos e proteínas; Instrumental innovations in capillary electrophoresis with electrochemical detection in the analysis of mono and oligosaccharides, amino acids and proteins

Blanes, Lucas
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 27/03/2008 PT
Relevância na Pesquisa
17.25%
A presente tese é o resultado de um complexo trabalho de instrumentação em Eletroforese Capilar (CE) com detecção condutométrica sem contato (C4D) visando à análise de biomoléculas. No que diz respeito à instrumentação, dois equipamentos de CE (H1 e B1), que possuem um sistema único de eletrólise separada (MSE), foram desenvolvidos. H1 possui apenas um capilar, e nele foi desenvolvida a maioria dos experimentos apresentados nesse trabalho. Neste equipamento, foi implementado um sistema de marcas térmicas, cuja aplicação foi demonstrada na correção de variações nos tempos de migração dos íons Na+ e K+ presentes em clara de ovos. Também realizamos a separação e detecção (10 µmol·L-1 ) de proteínas entre 12 e 66 kDa, comprovando que a detecção dessas moléculas é factível, desde que se use agentes que evitem a adsorção. Experimentos de separação e detecção de quitooligossacarídeos produzidos enzimaticamente também foram desenvolvidos em H1. Com o uso de NaOH como eletrólito de corrida acrescido de acetonitrila como agente modificador, verificamos a separação completa de seis quitooligossacarídeos (C1 a C6) com limites de detecção e quantificação inferiores a 3 µmol·L-1 e 10 µmol·L-1 ...

Innovative approach for producing injectable, biodegradable materials using chitooligosaccharides and green chemistry

Boesel, L. F.; Reis, R. L.; San Román, J.
Fonte: ACS Publications Publicador: ACS Publications
Tipo: Artigo de Revista Científica
Publicado em //2009 ENG
Relevância na Pesquisa
27.77%
Although there are a number of injectable biomaterials currently under development, they present some drawbacks such as being based on synthetic polymers, needing toxic or aggressive synthesis procedures or using raw materials with low availability and/or high production costs. Having this in mind, a novel injectable biomaterial using chitooligosaccharides as starting materials was developed. This system uses a widely available and cheap polymer from marine biomass (chitosan), which can be turned into an injectable material by water-based and ecologically friendly reactions. Chitooligosaccharides were functionalized with methacrylic groups, to allow in situ crosslinking. The degree of substitution, as determined by 1H NMR, varied between 5 and 50%. The system was characterized in terms of kinetics of gel formation, rheology, degradation behavior and in vitro cytotoxicity. The gelation time could be easily tailored between 1.5 and 60 min by changing the conditions of the methacrylation reaction, and the final gel presented rheological properties typical of strong gels, that is, shear stresses in the kPa range. The cross-linked gel was degradable and nontoxic, presenting indeed an interesting cytokinetic effect. Injectable materials based on chitooligosaccharides are...

Antioxidant activity of chitooligosaccharides upon two biological systems: Erythrocytes and bacteriophages

Fernandes, João C.; Eaton, Peter; Nascimento, Henrique; Gião, Maria S.; Ramos, Óscar S.; Belo, Luís; Santos-Silva, Alice; Pintado, Manuela E.; Malcata, F. Xavier
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2010 ENG
Relevância na Pesquisa
37.57%
Most of the reports to date on the antioxidant capacity of chitosans and chitooligosaccharides (COS) are based on strictly chemical methods. When studying antioxidants with potential in vivo applications, the method used to evaluate the antioxidant activity should be representative of the conditions in which the antioxidant might have a protective effect. In this work we evaluate the antioxidant activity of two COS mixtures and a low MW chitosan (LMWC) upon two biological oxidizable substrates – erythrocytes and phages, subjected to accelerated oxidation conditions. Our results suggest that COS/LMWC can be used as antioxidants in biological systems. All the tested compounds reduced either the hemolytic and DNA damage, by inhibiting H2O2- and AAPH-radicals. However, the results obtained for these biological assays did not reveal a dose dependence, contrary to the chemical assay, suggesting that the protective concentrations should be established, in order to prevent enhancement of the oxidative damage – i.e. a prooxidant effect.

Cytotoxicity and genotoxicity of chitooligosaccharides upon lymphocytes

Fernandes, João C.; Borges, Margarida; Nascimento, Henrique; Bronze-da-Rocha, Elsa; Ramos, Oscar S.; Pintado, Manuela E.; Malcata, F. Xavier; Santos-Silva, Alice
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2011 ENG
Relevância na Pesquisa
27.25%
Two COS mixtures and a low molecular weight chitosan (LMWC) were tested for potential cytotoxicity and genotoxicity upon human lymphocytes. Genotoxicity was evaluated in vitro by cytokinesis-blocked micronucleus and alkaline comet assays, while cytotoxicity was assessed by flow cytometry analysis. Our results suggest that COS do not exhibit any genotoxicity upon human lymphocytes, independently of MW or concentration. However, above 0.07 mg/mL COS induced strong cytotoxic effects. According to the concentration used, such cytotoxicity will induce cell death, essentially by necrosis (>0.10 mg/mL) and/or apoptosis (<0.10 mg/mL). The level of necrosis/apoptosis induced by high COS concentrations, suggests a promising use as apoptosis inducers in specific cancer situations.

Inhibition of Bladder Tumor Growth by Chitooligosaccharides in an Experimental Carcinogenesis Model

Fernandes, João C.; Sereno, José; Garrido, Patricia; Parada, Belmiro; Cunha, Maria F. X.; Reis, Flávio; Pintado, M. E.; Santos-Silva, Alice
Fonte: MDPI - Multidisciplinary Digital Publishing Institute Publicador: MDPI - Multidisciplinary Digital Publishing Institute
Tipo: Artigo de Revista Científica
Publicado em //2012 ENG
Relevância na Pesquisa
37.77%
Urinary bladder cancer is one of the most common cancers worldwide, with the highest incidence in industrialized countries. Patients with cancer commonly use unconventional and complementary therapy including nutraceuticals. In this study we evaluated the efficacy of chitooligosaccharides (in orange juice) in rat bladder cancer chemoprevention and as therapeutic agent, on a rat model of urinary bladder carcinogenesis induced with N-butyl-N-(4-hydroxybutyl) nitrosamine. Results indicate that chitooligosaccharides may have a preventive effect on bladder cancer development and a curative effect upon established bladder tumors, dependent on the concentration ingested 500 mg/kg b.w., every three days, showed capacity to inhibit and prevent the proliferation of bladder cancer; however, this was associated with secondary effects such as hypercholesterolemia and hypertriglyceridemia. The use of lower doses (50 and 250 mg/kg b.w.) showed only therapeutic effects. It is further suggested that this antitumor effect might be due to its expected anti-inflammatory action, as well as by mechanisms not directly dependent of COX-2 inhibition, such as cellular proliferation control and improvement in antioxidant profile.

Desenvolvimento e caracterização de filmes à base de proteínas do soro do leite : potencial funcionalização com quitosanos

Ferreira, Catarina de Oliveira
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
POR
Relevância na Pesquisa
17.77%
O objectivo deste projecto consistiu na preparação de filmes comestíveis à base de proteínas do soro do leite (WPI) a pH 7 na presença de quitosano, como potenciais revestimentos de queijos, pois este apresenta propriedades biológicas interessantes, nomeadamente, actividade antimicrobiana. Com a incorporação deste polissacarídeo na matriz proteica, pretendia-se verificar se a sua presença provocaria uma melhoria das propriedades mecânicas e de barreira dos filmes de WPI. No entanto, uma vez que o quitosano é um polissacarídeo catiónico, chegou-se à conclusão que a mistura destes dois polímeros em solução a pH superior ao ponto isoeléctrico do WPI (pI 5,2), conduzia à precipitação dos mesmos. Deste modo, na impossibilidade de formar filmes de WPI a pH7 na presença de quitosano de massa molecular média, procedeu-se à preparação de filmes à base de quitosano e WPI a pH 3,5 nas seguintes proporções: 1:0, 6:1, 3:1, 2:1, 1:1, 1:2 e 1:3 (quitosano:proteína), mantendo constante a quantidade total de polímero por unidade de área. Neste caso, utilizou-se um filme de quitosano como controlo porque a pH<6,5 as pontes dissulfureto não se estabelecem entre as cadeias proteicas, pelo menos em número que possibilite...

Nodule-Inducing Activity of Synthetic Sinorhizobium meliloti Nodulation Factors and Related Lipo-Chitooligosaccharides on Alfalfa. Importance of the Acyl Chain Structure1

Demont-Caulet, Nathalie; Maillet, Fabienne; Tailler, Denis; Jacquinet, Jean-Claude; Promé, Jean-Claude; Nicolaou, Kyriacos C.; Truchet, Georges; Beau, Jean-Marie; Dénarié, Jean
Fonte: American Society of Plant Physiologists Publicador: American Society of Plant Physiologists
Tipo: Artigo de Revista Científica
Publicado em /05/1999 EN
Relevância na Pesquisa
27.25%
Sinorhizobium meliloti nodulation factors (NFs) elicit a number of symbiotic responses in alfalfa (Medicago sativa) roots. Using a semiquantitative nodulation assay, we have shown that chemically synthesized NFs trigger nodule formation in the same range of concentrations (down to 10−10 m) as natural NFs. The absence of O-sulfate or O-acetate substitutions resulted in a decrease in morphogenic activity of more than 100-fold and approximately 10-fold, respectively. To address the question of the influence of the structure of the N-acyl chain, we synthesized a series of sulfated tetrameric lipo-chitooligosaccharides (LCOs) having fatty acids of different lengths and with unsaturations either conjugated to the carbonyl group (2E) or located in the middle of the chain (9Z). A nonacylated, sulfated chitin tetramer was unable to elicit nodule formation. Acylation with short (C8) chains rendered the LCO active at 10−7 m. The optimal chain length was C16, with the C16-LCO being more than 10-fold more active than the C12- and C18-LCOs. Unsaturations were important, and the diunsaturated 2E,9Z LCO was more active than the monounsaturated LCOs. We discuss different hypotheses for the role of the acyl chain in NF perception.

Production of Chitooligosaccharides and Their Potential Applications in Medicine

Aam, Berit B.; Heggset, Ellinor B.; Norberg, Anne Line; Sørlie, Morten; Vårum, Kjell M.; Eijsink, Vincent G. H.
Fonte: Molecular Diversity Preservation International Publicador: Molecular Diversity Preservation International
Tipo: Artigo de Revista Científica
Publicado em 27/04/2010 EN
Relevância na Pesquisa
27.25%
Chitooligosaccharides (CHOS) are homo- or heterooligomers of N-acetylglucosamine and D-glucosamine. CHOS can be produced using chitin or chitosan as a starting material, using enzymatic conversions, chemical methods or combinations thereof. Production of well-defined CHOS-mixtures, or even pure CHOS, is of great interest since these oligosaccharides are thought to have several interesting bioactivities. Understanding the mechanisms underlying these bioactivities is of major importance. However, so far in-depth knowledge on the mode-of-action of CHOS is scarce, one major reason being that most published studies are done with badly characterized heterogeneous mixtures of CHOS. Production of CHOS that are well-defined in terms of length, degree of N-acetylation, and sequence is not straightforward. Here we provide an overview of techniques that may be used to produce and characterize reasonably well-defined CHOS fractions. We also present possible medical applications of CHOS, including tumor growth inhibition and inhibition of TH2-induced inflammation in asthma, as well as use as a bone-strengthener in osteoporosis, a vector for gene delivery, an antibacterial agent, an antifungal agent, an anti-malaria agent, or a hemostatic agent in wound-dressings. By using well-defined CHOS-mixtures it will become possible to obtain a better understanding of the mechanisms underlying these bioactivities.

Anti-Inflammatory Activity of Chitooligosaccharides in Vivo

Fernandes, João C.; Spindola, Humberto; de Sousa, Vanessa; Santos-Silva, Alice; Pintado, Manuela E.; Malcata, Francisco Xavier; Carvalho, João E.
Fonte: Molecular Diversity Preservation International Publicador: Molecular Diversity Preservation International
Tipo: Artigo de Revista Científica
Publicado em 28/05/2010 EN
Relevância na Pesquisa
27.25%
All the reports to date on the anti-inflammatory activity of chitooligosaccharides (COS) are mostly based on in vitro methods. In this work, the anti-inflammatory activity of two COS mixtures is characterized in vivo (using balb/c mice), following the carrageenan-induced paw edema method. This is a widely accepted animal model of acute inflammation to evaluate the anti-inflammatory effect of drugs. Our data suggest that COS possess anti-inflammatory activity, which is dependent on dose and, at higher doses, also on the molecular weight. A single dose of 500 mg/kg b.w. weight may be suitable to treat acute inflammation cases; however, further studies are needed to ascertain the effect upon longer inflammation periods as well as studies upon the bioavailability of these compounds.

Synthesis of Long-Chain Chitooligosaccharides by a Hypertransglycosylating Processive Endochitinase of Serratia proteamaculans 568

Purushotham, Pallinti; Podile, Appa Rao
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /08/2012 EN
Relevância na Pesquisa
27.25%
We describe the heterologous expression and characterization of a 407-residue single-domain glycosyl hydrolase family 18 chitinase (SpChiD) from Gram-negative Serratia proteamaculans 568 that has unprecedented catalytic properties. SpChiD was optimally active at pH 6.0 and 40°C, where it showed a Km of 83 mg ml−1, a kcat of 3.9 × 102 h−1, and a kcat/Km of 4.7 h mg−1 ml−1 on colloidal chitin. On chitobiose, the Km, kcat, and kcat/Km were 203 μM, 1.3 × 102 h−1, and 0.62 h−1 μM−1, respectively. Hydrolytic activity on chitooligosaccharides (CHOS) and colloidal chitin indicated that SpChiD was an endo-acting processive enzyme, with the unique ability to convert released chitobiose to N-acetylglucosamine, the major end product. SpChiD showed hyper transglycosylation (TG) with trimer-hexamer CHOS substrates, generating considerable amounts of long-chain CHOS. The TG activity of SpChiD was dependent on both the length and concentration of the oligomeric substrate and also on the enzyme concentration. The length and amount of accumulated TG products increased with increases in the length of the substrate and its concentration and decreased with increases in the enzyme concentration. The SpChiD bound to insoluble and soluble chitin substrates despite the absence of accessory domains. Sequence alignments and structural modeling indicated that SpChiD would have a deep substrate-binding groove lined with aromatic residues...

Inhibition of Bladder Tumor Growth by Chitooligosaccharides in an Experimental Carcinogenesis Model

Fernandes, João C.; Sereno, José; Garrido, Patricia; Parada, Belmiro; Cunha, Maria F. X.; Reis, Flávio; Pintado, Manuela E.; Santos-Silva, Alice
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 26/11/2012 EN
Relevância na Pesquisa
27.57%
Urinary bladder cancer is one of the most common cancers worldwide, with the highest incidence in industrialized countries. Patients with cancer commonly use unconventional and complementary therapy including nutraceuticals. In this study we evaluated the efficacy of chitooligosaccharides (in orange juice) in rat bladder cancer chemoprevention and as therapeutic agent, on a rat model of urinary bladder carcinogenesis induced with N-butyl-N-(4-hydroxybutyl) nitrosamine. Results indicate that chitooligosaccharides may have a preventive effect on bladder cancer development and a curative effect upon established bladder tumors, dependent on the concentration ingested 500 mg/kg b.w., every three days, showed capacity to inhibit and prevent the proliferation of bladder cancer; however, this was associated with secondary effects such as hypercholesterolemia and hypertriglyceridemia. The use of lower doses (50 and 250 mg/kg b.w.) showed only therapeutic effects. It is further suggested that this antitumor effect might be due to its expected anti-inflammatory action, as well as by mechanisms not directly dependent of COX-2 inhibition, such as cellular proliferation control and improvement in antioxidant profile.

Biocompatibility and Alkaline Phosphatase Activity of Phosphorylated Chitooligosaccharides on the Osteosarcoma MG63 Cell Line

Venkatesan, Jayachandran; Pangestuti, Ratih; Qian, Zhong-Ji; Ryu, BoMi; Kim, Se-Kwon
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 22/10/2010 EN
Relevância na Pesquisa
27.25%
Phosphorylated chitooligosaccharides (P-COS) were prepared using a H3PO4, P2O5, Et3PO4 and hexanol solvent system. The P-COS were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Thermo gravimetric-Differential Thermal Analyzer (TG-DTA), 13C NMR, 31P NMR, X-ray diffraction analysis, solubility studies, biocompatibility and Alkaline Phosphatase Activity (ALP). The results reveal that phosphorylation occurred at the C3 and C6 position of OH groups and the C2 position of NH2 group. FT-IR confirmed no decomposition in pyranose ring in P-COS even with heating and treatment in acidic conditions. The amorphous nature of P-COS was confirmed by X-ray diffraction analysis. Further, the biocompatibility and alkaline phosphatase activity of P-COS were checked against the osteosarcoma MG63 cell line at different concentrations and no cytotoxicity was observed. After 12 h and 24 h of incubation, the ALP activity of P-COS was higher compared with the control group. These results suggest that P-COS is a biocompatible material and in future P-COS could open up a number of promising pharmaceutical and clinical applications to mankind.

Antidiabetic effects of chitooligosaccharides on pancreatic islet cells in streptozotocin-induced diabetic rats

Liu, Bing; Liu, Wan-Shun; Han, Bao-Qin; Sun, Yu-Ying
Fonte: Baishideng Publishing Group Co., Limited Publicador: Baishideng Publishing Group Co., Limited
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.25%
AIM: To investigate the effect of chitooligosaccharides on proliferation of pancreatic islet cells, release of insulin and 2 h plasma glucose in streptozotocin-induced diabetic rats.

Characterization of an Acidic Chitinase from Seeds of Black Soybean (Glycine max (L) Merr Tainan No. 3)

Chang, Ya-Min; Chen, Li-Chun; Wang, Hsin-Yi; Chiang, Chui-Liang; Chang, Chen-Tien; Chung, Yun-Chin
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 01/12/2014 EN
Relevância na Pesquisa
17.57%
Using 4-methylumbelliferyl-β-D-N,N′,N″-triacetylchitotrioside (4-MU-GlcNAc3) as a substrate, an acidic chitinase was purified from seeds of black soybean (Glycine max Tainan no. 3) by ammonium sulfate fractionation and three successive steps of column chromatography. The purified chitinase was a monomeric enzyme with molecular mass of 20.1 kDa and isoelectric point of 4.34. The enzyme catalyzed the hydrolysis of synthetic substrates p-nitrophenyl N-acetyl chitooligosaccharides with chain length from 3 to 5 (GlcNAcn, n = 3-5), and pNp-GlcNAc4 was the most degradable substrate. Using pNp-GlcNAc4 as a substrate, the optimal pH for the enzyme reaction was 4.0; kinetic parameters Km and kcat were 245 µM and 10.31 min−1, respectively. This enzyme also showed activity toward CM-chitin-RBV, a polymer form of chitin, and N-acetyl chitooligosaccharides, an oligomer form of chitin. The smallest oligomer substrate was an N-acetylglucosamine tetramer. These results suggested that this enzyme was an endo-splitting chitinase with short substrate cleavage activity and useful for biotechnological applications, in particular for the production of N-acetyl chitooligosaccharides.

Produção de enzimas quitosanolíticas utilizando Paenibacillus ehimensis e Paenibacillus chitinolyticus para obtenção de quitoologossacarídeos

Araujo, Nathalia Kelly de
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Bioquímica; Bioquímica; Biologia Molecular Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Bioquímica; Bioquímica; Biologia Molecular
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
27.25%
The acquisition of oligosaccharides from chitosan has been the subject of several studies in the pharmaceutical, biochemical, food and medical due to functional properties of these compounds. This study aimed to boost its production of chitooligosaccharides (COS) through the optimization of production and characterization of chitosanolytic enzymes secreted by microorganisms Paenibacillus chitinolyticus and Paenibacillus ehimensis, and evaluating the antioxidant potential of the products obtained. In the process of optimizing the production of chitosanase were employed strategies Fractional Factorial Experimental Design and Central Composite Rotatable Design. The results identified the chitosan, peptone and yeast extract as the components that influenced the production of chitosanase by these microorganisms. With the optimization of the culture media was possible to obtain an increase of approximately 8.1 times (from 0.043 to 0.35 U.mL U.mL-1) and 7.6 times (from 0.08 U.mL-1 to 0.61 U.mL-1) in the enzymatic activity of chitosanase produced by P. chitinolyticus and P. ehimensis respectively. Enzyme complexes showed high stability in temperature ranges between 30º and 55º C and pH between 5.0 and 9.0. Has seen the share of organic solvents...

Développement de méthodes de séparation des chitooligosaccharides obtenus par déacétylation enzymatique

Tang, Marie-Christine
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
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27.25%
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Maize growth promotion by inoculation with Azospirillum brasilense and metabolites of Rhizobium tropici enriched on lipo-chitooligosaccharides (LCOs)

Marks, Bettina Berquó; Megías, Manuel; Ollero, Francisco Javier; Nogueira, Marco Antonio; Araujo, Ricardo Silva; Hungria, Mariangela
Fonte: Springer Berlin Heidelberg Publicador: Springer Berlin Heidelberg
Tipo: Artigo de Revista Científica
Publicado em 14/11/2015 EN
Relevância na Pesquisa
27.25%
There is an increasing interest in the development and use of inoculants carrying plant growth-promoting bacteria (PGPB) in crops of agronomic interest. The great majority of the inoculants commercialized worldwide contain rhizobia for legume crops, but the use of PGPB as Azospirillum spp. for non-legume is expanding, as well as of inoculants combining microorganisms and microbial metabolites. In this study we evaluated the effects of inoculants containing Azospirillum brasilense with or without metabolites of Rhizobium tropici strain CIAT 899 highly enriched in lipo-chitooligosaccharides (LCOs) in six field experiments performed for three summer crop seasons in Brazil with maize (Zea mays L.). Inoculants and metabolites were applied either at sowing by seed inoculation, or by leaf spray at the V3 stage of plant growth. Improvement in shoot dry weight (SDW) and total N accumulated in shoots (TNS) by single, but especially by dual inoculation was observed in some of the experiments. Statistically significant increases in grain yield in relation to the non-inoculated control were observed in five out of six experiments when maize was inoculated with Azospirillum supplied with enriched metabolites of R. tropici applied by seed or leaf spray inoculation. The results give strength to the development of a new generation of inoculants carrying microorganisms and microbial molecules.

Edible films and coatings for cheese; Filmes e revestimentos comestíveis para queijos

Orosa, Maria Inês Franco
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
27.25%
Over the last years there has been an increasing interest to replace synthetic materials by biodegradable ones, due to the ecological problems. Edible and biodegradable films can be produced using polysaccharides, lipids, proteins and composites, and act as a package without damaging the environment. By choosing a suitable coating composition it is possible to preserve several desired properties of a certain food product. Important properties should be considered, such as mechanical, functional and barrier properties. The main goal of this study was to evaluate edible films and coatings from plant proteins (pea, soy), with incorporated natural antimicrobial and antioxidant agents, to potentially protect cheese from physico-chemical and microbial deterioration and to preserve the organoleptic characteristics, especially of sliced cheeses. The work performed focused mainly on the preparation and characterization of pea protein films, with added chitooligosaccharides (COs) (0.5%, 1% and 2%) and two types of essential oils at 1%, bay and thyme oils. Films with 0.5% of COs showed the highest values of Young’s modulus, tensile strength and elongation. Regarding the barrier properties, the film with 1% of COs showed the lower permeability value. Addition of small amounts of COs may be advantageous to improve the mechanical properties of the PPI films...