Academic literature on the topic 'Agarases'
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Journal articles on the topic "Agarases"
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Han, Wenjun, Yuanyuan Cheng, Dandan Wang, Shumin Wang, Huihui Liu, Jingyan Gu, Zhihong Wu, and Fuchuan Li. "Biochemical Characteristics and Substrate Degradation Pattern of a Novel Exo-Type β-Agarase from the Polysaccharide-Degrading Marine Bacterium Flammeovirga sp. Strain MY04." Applied and Environmental Microbiology 82, no. 16 (June 3, 2016): 4944–54. http://dx.doi.org/10.1128/aem.00393-16.
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ABSTRACTExo-type agarases release disaccharide units (3,6-anhydro-l-galactopyranose-α-1,3-d-galactose) from the agarose chain and, in combination with endo-type agarases, play important roles in the processive degradation of agarose. Several exo-agarases have been identified. However, their substrate-degrading patterns and corresponding mechanisms are still unclear because of a lack of proper technologies for sugar chain analysis. Herein, we report the novel properties of AgaO, a disaccharide-producing agarase identified from the genusFlammeovirga. AgaO is a 705-amino-acid protein that is unique to strain MY04. It shares sequence identities of less than 40% with reported GH50 β-agarases. Recombinant AgaO (rAgaO) yields disaccharides as the sole final product when degrading agarose and associated oligosaccharides. Its smallest substrate is a neoagarotetraose, and its disaccharide/agarose conversion ratio is 0.5. Using fluorescence labeling and two-stage mass spectrometry analysis, we demonstrate that the disaccharide products are neoagarobiose products instead of agarobiose products, as verified by13C nuclear magnetic resonance spectrum analysis. Therefore, we provide a useful oligosaccharide sequencing method to determine the patterns of enzyme cleavage of glycosidic bonds. Moreover, AgaO produces neoagarobiose products by gradually cleaving the units from the nonreducing end of fluorescently labeled sugar chains, and so our method represents a novel biochemical visualization of the exolytic pattern of an agarase. Various truncated AgaO proteins lost their disaccharide-producing capabilities, indicating a strict structure-function relationship for the whole enzyme. This study provides insights into the novel catalytic mechanism and enzymatic properties of an exo-type β-agarase for the benefit of potential future applications.IMPORTANCEExo-type agarases can degrade agarose to yield disaccharides almost exclusively, and therefore, they are important tools for disaccharide preparation. However, their enzymatic mechanisms and agarose degradation patterns are still unclear due to the lack of proper technologies for sugar chain analysis. In this study, AgaO was identified as an exo-type agarase of agarose-degradingFlammeovirgabacteria, representing a novel branch of glycoside hydrolase family 50. Using fluorescence labeling, high-performance liquid chromatography, and mass spectrum analysis technologies, we provide a useful oligosaccharide sequencing method to determine the patterns of enzyme cleavage of glycosidic bonds. We also demonstrate that AgaO produces neoagarobiose by gradually cleaving disaccharides from the nonreducing end of fluorescently labeled sugars. This study will benefit future enzyme applications and oligosaccharide studies.
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Flament, Didier, Tristan Barbeyron, Murielle Jam, Philippe Potin, Mirjam Czjzek, Bernard Kloareg, and Gurvan Michel. "Alpha-Agarases Define a New Family of Glycoside Hydrolases, Distinct from Beta-Agarase Families." Applied and Environmental Microbiology 73, no. 14 (May 18, 2007): 4691–94. http://dx.doi.org/10.1128/aem.00496-07.
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ABSTRACT The gene encoding the α-agarase from “Alteromonas agarilytica” (proposed name) has been cloned and sequenced. The gene product (154 kDa) is unrelated to β-agarases and instead belongs to a new family of glycoside hydrolases (GH96). The α-agarase also displays a complex modularity, with the presence of five thrombospondin type 3 repeats and three carbohydrate-binding modules.
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Liao, Li, Xue-Wei Xu, Xia-Wei Jiang, Yi Cao, Na Yi, Ying-Yi Huo, Yue-Hong Wu, Xu-Fen Zhu, Xin-qi Zhang, and Min Wu. "Cloning, Expression, and Characterization of a New β-Agarase fromVibriosp. Strain CN41." Applied and Environmental Microbiology 77, no. 19 (August 5, 2011): 7077–79. http://dx.doi.org/10.1128/aem.05364-11.
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ABSTRACTA new agarase, AgaACN41, cloned fromVibriosp. strain CN41, consists of 990 amino acids, with only 49% amino acid sequence identity with known β-agarases. AgaACN41belongs to the GH50 (glycoside hydrolase 50) family but yields neoagarotetraose as the end product. AgaACN41was expressed and characterized.
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Achudhan, Arunmozhi Bharathi, and Mahalakshmi Velrajan. "MOLECULAR CHARACTERIZATION OF β-AGARASE PRODUCED BY SPHINGOMONAS PAUCIMOBILIS, A MARINE BACTERIUM." Bacterial Empire 4, no. 2 (April 2, 2021): e159. http://dx.doi.org/10.36547/be.159.
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Agarases are enzymes that catalyze the hydrolysis of agar. The present study was carried out to isolate the agar degrading microorganisms from marine source. The characterization of agar degrading organism was done by VITEK 2.0 automated instrument, which confirmed the sample as Spinghomonas paucimobilis by a set of 64 biochemical tests. Production of agarase, an extracellular enzyme was done in mineral salt broth with agar and the enzyme was purified by ammonium sulphate precipitation and dialysis. The molecular weight of the enzyme was determined by SDS-PAGE method. Fourier transform infrared spectroscopy analysis was done to authenticate the degree of degradation of agar. The presence of agarase gene was targeted using the required primers and amplified by Polymerase chain reaction. Also the study addresses the problem of solid waste generation of agar waste by any microbiological laboratories and industries.
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Kawaroe, Mujizat, Dwi Setyaningsih, Bertoka Fajar SP Negara, and Dina Augustine. "Potential Marine Fungi Hypocreaceae sp. as Agarase Enzyme to Hydrolyze Macroalgae Gelidium latifolium (Potensi Jamur Hypocreaceae sp. sebagai Enzim Agarase untuk menghidrolisis Makroalga Gelidium latifolium)." ILMU KELAUTAN: Indonesian Journal of Marine Sciences 20, no. 1 (March 3, 2015): 45. http://dx.doi.org/10.14710/ik.ijms.20.1.45-51.
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Agarase dapat mendegradasi agar ke oligosakarida dan memiliki banyak manfaat untuk makanan, kosmetik, dan lain-lain. Banyak spesies pendegradasi agar adalah organismelaut. Beberapa agarase telah diisolasi dari genera yang berbeda dari mikroorganisme yang ditemukan di air dan sedimen laut. Hypocreaceae sp. diisolasi dari air laut Pulau Pari, Kepulauan Seribu, Jakarta, Indonesia. Berdasarkan hasil identifikasi gen 16S rDNA dari 500 basis pasangan, isolat A10 memiliki 99% kesamaan dengan Hypocreaceae sp. Enzim agarase ekstraseluler dari Hypocreaceae sp. memiliki pH dan suhu optimum pada 8 TrisHCl (0,148 μ.mL-1) dan 50°C (0,182 μ.mL-1), masing-masing. Enzim Agarase dari Hypocreaceae sp. mencapai kondisi optimum pada aktivitas enzim tertinggi selama inkubasi dalam 24 jam (0,323 μ.mL-1). SDS page mengungkapkan bahwa ada dua band dari protein yang dihasilkan oleh agarase dari Hypocreaceae sp. yang berada di berat molekul 39 kDa dan 44 kDa dan hidrolisis Gelidium latifolium diperoleh 0,88% etanol. Kata kunci: enzim agarase, Hypocreaceae sp., hidrolisis, fungi, rDNA. Agarase can degradedagarto oligosaccharide and has a lot of benefits for food, cosmetics, and others. Many species of agar- degrader are marine-organism. Several agarases have been isolated from different genera of microorganisms found in seawater and marine sediments. Hypocreaceae sp. was isolated from sea water of Pari Islands, Seribu Islands, Jakarta, Indonesia. Based on the results of the 16S rDNA gene identification of 500 base pairs, A10 isolates had 99 % similarity toHypocreaceae sp. The extracellular agarase enzyme from Hypocreaceae sp. have optimum pH and temperature at 8 TrisHCl (0.148 µ.mL-1) and 50 °C (0.182 µ.mL-1), respectively. Agarase enzyme of Hypocreaceae sp. reach an optimum condition at the highest enzyme activity during incubation in 24 hours (0.323 µ.mL-1). SDS Page revealed that there are two bands of protein produced by agarase of Hypocreaceae sp. which are at molecular weight of 39 kDa and 44 kDa and hydrolisis of Gelidium latifolium obtained 0,88% ethanol. Key words: agarase enzym, Hypocreaceae sp., hydrolysis, marine fungi, rDNA
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Raut, Avinash A., and Shyam S. Bajekal. "An agar degrading diazotrophic actinobacteria from hyperalkaline meteoric lonar crater lake - a primary study." Microbiology Research 2, no. 1 (September 15, 2011): 10. http://dx.doi.org/10.4081/mr.2011.e10.
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There are very few reports on agarases being produced by actinobacteria, Streptomyces coelicolor being the only one known since decades for its agar degrading property. Here we report an agar degrading diazotrophic actinobacterium other than Streptomyces coelicolor, isolated from the littoral soil of Lonar Lake situated in Buldhana district of Maharashtra, India, a lake characterised by high alkalinity, carbonates, bicarbonates, and algal blooms. The lake has a mean diameter of 1800 meters. The Gram-positive filamentous rod grew in a simple medium of pH 10.5 containing agar as a sole source of carbon. The agar degrading property was detected by the appearance of depressions around each colony after 48 h of growth. The enzyme responsible for this degradation, agarase was also detected and estimated. The isolate also grew on Ashby’s Nitrogen free Mannitol Medium aerobically and fixed nitrogen. Morphological, physiological and biochemical characteristics of the isolate are presented in this paper.
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Wang, Wenxin, Jianxin Wang, Ruihua Yan, Runying Zeng, Yaqiang Zuo, Dingquan Wang, and Wu Qu. "Expression and Characterization of a Novel Cold-Adapted and Stable β-Agarase Gene agaW1540 from the Deep-Sea Bacterium Shewanella sp. WPAGA9." Marine Drugs 19, no. 8 (July 29, 2021): 431. http://dx.doi.org/10.3390/md19080431.
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The neoagaro-oligosaccharides, degraded from agarose by agarases, are important natural substances with many bioactivities. In this study, a novel agarase gene, agaW1540, from the genome of a deep-sea bacterium Shewanella sp. WPAGA9, was expressed, and the recombinant AgaW1540 (rAgaW1540) displayed the maximum activity under the optimal pH and temperature of 7.0 and 35 °C, respectively. rAgaW1540 retained 85.4% of its maximum activity at 0 °C and retained more than 92% of its maximum activity at the temperature range of 20–40 °C and the pH range of 4.0–9.0, respectively, indicating its extensive working temperature and pH values. The activity of rAgaW1540 was dramatically suppressed by Cu2+ and Zn2+, whereas Fe2+ displayed an intensification of enzymatic activity. The Km and Vmax of rAgaW1540 for agarose degradation were 15.7 mg/mL and 23.4 U/mg, respectively. rAgaW1540 retained 94.7%, 97.9%, and 42.4% of its maximum activity after incubation at 20 °C, 25 °C, and 30 °C for 60 min, respectively. Thin-layer chromatography and ion chromatography analyses verified that rAgaW1540 is an endo-acting β-agarase that degrades agarose into neoagarotetraose and neoagarohexaose as the main products. The wide variety of working conditions and stable activity at room temperatures make rAgaW1540an appropriate bio-tool for further industrial production of neoagaro-oligosaccharides.
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Xie, Zhangzhang, Weitie Lin, and Jianfei Luo. "Comparative Phenotype and Genome Analysis ofCellvibriosp. PR1, a Xylanolytic and Agarolytic Bacterium from the Pearl River." BioMed Research International 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/6304248.
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Cellvibriosp. PR1 is a xylanolytic and agarolytic bacterium isolated from the Pearl River. Strain PR1 is closely related toCellvibrio fibrivoransandC. ostraviensis(identity > 98%). The xylanase and agarase contents of strain PR1 reach up to 15.4 and 25.9 U/mL, respectively. The major cellular fatty acids consisted of C16:0 (36.7%), C18:0 (8.8%), C20:0 (6.8%), C15:0iso 2-OH or/and C16:1ω7c (17.4%), and C18:1ω7c or/and C18:1ω6c (6.7%). A total of 251 CAZyme modules (63 CBMs, 20 CEs, 128 GHs, 38 GTs, and 2 PLs) were identified from 3,730 predicted proteins. Genomic analysis suggested that strain PR1 has a complete xylan-hydrolyzing (5β-xylanases, 16β-xylosidases, 17α-arabinofuranosidases, 9 acetyl xylan esterases, 4α-glucuronidases, and 2 ferulic acid esterases) and agar-hydrolyzing enzyme system (2β-agarases and 2α-neoagarooligosaccharide hydrolases). In addition, the main metabolic pathways of xylose, arabinose, and galactose are established in the genome-wide analysis. This study shows that strain PR1 contains a large number of glycoside hydrolases.
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Ekborg, Nathan A., Larry E. Taylor, Atkinson G. Longmire, Bernard Henrissat, Ronald M. Weiner, and Steven W. Hutcheson. "Genomic and Proteomic Analyses of the Agarolytic System Expressed by Saccharophagus degradans 2-40." Applied and Environmental Microbiology 72, no. 5 (May 2006): 3396–405. http://dx.doi.org/10.1128/aem.72.5.3396-3405.2006.
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ABSTRACT Saccharophagus degradans 2-40 (formerly Microbulbifer degradans 2-40) is a marine gamma-subgroup proteobacterium capable of degrading many complex polysaccharides, such as agar. While several agarolytic systems have been characterized biochemically, the genetics of agarolytic systems have been only partially determined. By use of genomic, proteomic, and genetic approaches, the components of the S. degradans 2-40 agarolytic system were identified. Five agarases were identified in the S. degradans 2-40 genome. Aga50A and Aga50D include GH50 domains. Aga86C and Aga86E contain GH86 domains, whereas Aga16B carries a GH16 domain. Novel family 6 carbohydrate binding modules (CBM6) were identified in Aga16B and Aga86E. Aga86C has an amino-terminal acylation site, suggesting that it is surface associated. Aga16B, Aga86C, and Aga86E were detected by mass spectrometry in agarolytic fractions obtained from culture filtrates of agar-grown cells. Deletion analysis revealed that aga50A and aga86E were essential for the metabolism of agarose. Aga16B was shown to endolytically degrade agarose to release neoagarotetraose, similarly to a β-agarase I, whereas Aga86E was demonstrated to exolytically degrade agarose to form neoagarobiose. The agarolytic system of S. degradans 2-40 is thus predicted to be composed of a secreted endo-acting GH16-dependent depolymerase, a surface-associated GH50-dependent depolymerase, an exo-acting GH86-dependent agarase, and an α-neoagarobiose hydrolase to release galactose from agarose.
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Allouch, Julie, Murielle Jam, William Helbert, Tristan Barbeyron, Bernard Kloareg, Bernard Henrissat, and Mirjam Czjzek. "The Three-dimensional Structures of Two β-Agarases." Journal of Biological Chemistry 278, no. 47 (September 11, 2003): 47171–80. http://dx.doi.org/10.1074/jbc.m308313200.
Full textDissertations / Theses on the topic "Agarases"
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Allouch, Julie [Liberté Lumière]. "Etude structurale et fonctionnelle de deux béta-agarases de la famille 16 des glycoside hydrolases." Aix-Marseille 2, 2003. http://www.theses.fr/2003AIX22066.
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Hehemann, Jan-Hendrik. "Structural and functional organisation of the agarolytic enzyme system of the marine flavobacterium Zobellia galactanivorans." Paris 6, 2009. http://hal.upmc.fr/tel-01110381v1.
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Zobellia galactanivorans est une Flavobacterie marine capable de dégrader des polysaccharides complexes tels que l’agar qui est largement utilisé en biotechnologie et agroalimentaire. Dans l’écosystème marin les organismes photosynthétiques tels que les algues et les cyanobactéries sont les principaux producteurs de carbone organique. Cette source de carbone est utilisée par les bactéries marines qui sécrètent des glycosides hydrolases afin d’attaquer les algues ou d’hydrolyser la paroi des algues en décomposition. Pour comprendre les mécanismes de recyclage du carbone à partir de ces zones de nutrition préférentielles nous avons décidé d’analyser le système agarolytique de Z. Galactanivorans. Le génome bactérien complet a mis en évidence la présence de neuf agarases de la famille GH 16, confirmant que Z. Galactanivorans possède un système agarolytique complexe pour dégrader cette ressource naturel qu’est l’agar. Sept séquences originales ont été surexprimées grâce à une stratégie de clonage à moyen débit. Une nouvelle ß-agarase (AgaD) a été purifiée à l’homogénéité, puis cristallisée et les données de diffraction ont été collectées à une résolution de 1. 5 Å. La structure a été résolue par remplacement moléculaire et la caractérisation biochimique a été réalisée. De plus, les deux premières ?-porphyranases PorA et PorB ont été identifiées, cristallisées et caractérisées biochimiquement. La diversité d’enzymes agarolytiques reflète les adaptations biologiques dont ont fait preuve certaines bactéries pour s’accommoder à la grande variabilité de l’agarose de la paroi des algues rouges.
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Ekborg, Nathan Alexander. "The agarase system of saccharophagus degradans strain 2-40 analysis of the agarase system and protein localization /." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3188.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Cell Biology & Molecular Genetics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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BERNARD, ISABELLE. "Production de l'alpha-agarase par alteromonas agarlyticus." Compiègne, 1996. http://www.theses.fr/1995COMP872S.
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Les enzymes qui hydrolysene l'agarose, un polysaccharide compose d'une alternance de molecules de d-galactose et de 3,6-anhydro-l-galactose reliees entre elles par des liaisons beta1-4 et alpha1-3, sont appelees les beta-agarases et les alpha-agarases suivant la liaison hydrolysee. Seule l'agarase produite par alteromonas agarlyticus, une bacterie marine, a ete clairement definie comme etant une alpha-agarase. Notre etude a concerne l'analyse de sa production afin de pouvoir l'optimiser. L'activite enzymatique a ainsi ete multipliee par 3,6 (un maximum de production de 7,7 u. E par ml lors d'essais en fermenteur), ceci grace a une hydrolyse partielle de l'agar avant son utilisation. Une hydrolyse menagee a l'acide et a chaud produit une degradation partielle de l'agar au niveau des liaisons alpha liberant ainsi des agaro-oligosides, inducteurs de la production de l'alpha-agarase. L'existence d'une repression catabolique a aussi ete demontree. Cette derniere s'effectue vraisemblablement par l'intermediaire d'un produit libere par l'action de l'alpha-agarase sur l'agarose: l'agarotetraose. La production de cette enzyme est donc soumise au mecanisme d'induction-repression. Durant des essais de cultures en volume plus importants (20 et 100 litres) ayant donne lieu a une optimisation partielle des parametres de fermentation, des problemes (en microfiltration et ultrafiltration) lors de la recolte du surnageant ont ete mis en evidence. Des mutations aleatoires (par u. V. ) pour obtenir une synthese de l'agarase constitutive ont ete entreprises ; car une synthese constitutive de cette derniere pourrait permettre d'utiliser un milieu de culture depourvu d'agar, une perspective particulierement interessante economiquement et pratiquement. C'est pourquoi outre la poursuite de l'etude de la production en fermenteur de l'alpha-agarase (culture en continu par exemple), un remaniement genetique de cette enzyme peut aussi etre une perspective au travail deja realise
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ALISTE, ANTONIO J. "Efeito da radiacao na viscosidade de carragenanas, agaranas e alginatos utilizados na industria alimenticia." reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9281.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Schroeder, Declan Cosmo. "Isolation and characterization of a β(1-4) agarase of an epiphytic bacterial pathogen, Pseudoalteromonas gracilis B9, of the red alga, Gracilaria gracilis." Doctoral thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/4328.
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Aliste, Antonio João. "Uso de substâncias antioxidantes na resposta à radiação dos hidrocolóides carragenanas, agaranas e alginatos utilizados na indústria alimentícia." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-15052012-111215/.
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Carragenanas, agaranas e alginatos são hidrocolóides largamente utilizados em todo tipo de produtos alimentícios como aditivos espessantes. Eles não são absorvidos pelo organismo e, portanto não introduzem calorias extras na dieta. A irradiação se apresenta com grande potencial como um método alternativo na preservação de alimentos pois não induz aumento da temperatura, e é, portanto, de grande eficácia na descontaminação de ingredientes alimentícios sensíveis ao calor. Neste trabalho, soluções dos hidrocolóides agararana, carragenana e aiginato de sódio, foram irradiadas com diferentes doses (0-10 kGy) de radiação gama de Co-60 na presença de antioxidantes também utilizados na indústria alimentícia: ácido ascórbico, extrato vegetal de rosela (Híbiscus sabdariffa L.) e isofiavona de soja. As soluções dos polissacarídeos comestíveis agarana, carragenana e alginato de sódio mostraram ser bons sistemas para avaliar o efeito da radiação ionizante por apresentarem radiossensibilidade característica medida pelas mudanças na viscosidade. Os resultados obtidos mostram que esses antioxidantes apresentam, no geral, ação radioprotetora o que pode ser de grande valia nas aplicações futuras da irradiação de alimentos em escala comercial.Carrageenan, agaran e alginates are hydrocolloids largely employed in every kind of food products as stabilizing agent and viscosity builder. The human body does not absorb them, so they do not introduce extra calories in the diet. Irradiation is presented as an important alternative method in food preservation because do not induce temperature increase being of good efficiency in cold food ingredients decontamination. In this work aqueous solutions of carrageenan, agar e sodium alginate were gamma irradiated (0-10 kGy) in presence of ascorbic acid, roselle {Hibiscus sabdariffa L.) extract and soy isoflavone. Edible polysaccharide solutions showed to be suitable systems for the evaluation of ionizing radiation effects as they presented a singular radiosensitivity through viscosity changes. The results obtained showed that in general the antioxidants employed had a radioprotective action that can be of importance in the future commercial applications of food irradiation.
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ALISTE, ANTONIO J. "Uso de substancias antioxidantes na resposta a radiacao dos hidrocoloides carragenanas, agaranas e alginatos utilizados na industria alimenticia." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11386.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Vidal, Gabarró Marcel·la. "Estudi de l'expressió i secreció de proteïnes recombinants (agarasa i lacasa) en una soca SipY- de Streptomyces lividans." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/285079.
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La producció de proteïnes homòlogues i heteròlogues a escala industrial requereix sistemes
d’expressió variats i eficients. Els bacteris grampositius, com Streptomyces, poden ser una
alternativa per a la producció de proteïnes recombinants ja que aquestes són produïdes i
secretades al medi. La seqüenciació del genoma d’algunes espècies de Streptomyces i el seu
anàlisi post-genòmic ha permès determinar i caracteritzar la seva maquinària de secreció. Així,
se sap que els precursors de les proteïnes que s’han de secretar són exportats majoritàriament
per una via principal de secreció (via Sec) o bé per una via secundària (via Tat). Aquests
precursors contenen un pèptid senyal de tipus I que permet la seva correcta translocació a través
de la membrana plasmàtica, la seqüència del qual determina per quina de les dues vies es
dirigeix. Un cop translocades, les peptidases senyal de tipus I (SPases) processen la majoria
d’aquestes proteïnes secretades i les alliberen al medi extracel·lular en la seva forma madura.
Estudis previs en la maquinària de secreció han determinat que Streptomyces lividans té
quatre peptidases senyal Sip (SipW, SipX, SipY i SipZ) de les quals, SipY és la que desenvolupa el
paper majoritari. La soca deficient en aquesta proteïna SipY té la capacitat de secreció
notablement afectada però, paradoxalment, és un bon hoste per a la sobreproducció de
proteïnes secretades, ja que presenta una activitat proteàsica considerablement disminuïda.
En aquest treball s’ha estudiat la producció d’agarasa i de lacasa en la soca SipY- (S. lividans
ΔsipY) a escala de bioreactor per avaluar si aquesta soca pot ser considerada com a possible
hoste per a la producció de proteïnes recombinants per la indústria. Aquestes dues proteïnes se
secreten majoritàriament per la via Tat. En el cas de l’enzim agarasa, el gen expressat prové de
S. coelicolor A3(2) i s’ha produït l’enzim en discontinu amb la soca salvatge (S. lividans
TK21pAGAs5) i la soca mutada (S. lividans ΔsipYpAGAs5). La soca S. lividans ΔsipYpAGAs5 ha
presentat una millor producció i s’ha seleccionat el medi més adequat per tal de produir aquesta
proteïna estudiant el seu comportament operant en continu. També s’han estudiat diferents
estratègies en discontinu alimentat, entre les quals la major producció s’ha obtingut amb una
addició de mannitol i evitant que aquesta font de carboni s’esgoti en el medi.
En el cas de la lacasa, s’han construït tres soques en les quals el gen de la pròpia lacasa de S.
lividans és regulat per tres promotors diferents: el promotor propi de la lacasa, el promotor del
gen de resistència a eritromicina i el promotor del gen agarasa de S. coelicolor. La soca en el qual
el gen és regulat pel promotor del gen agarasa (S. lividans ΔsipYpFD-DagA-laccase) ha estat
seleccionada i s’ha estudiat la producció de l’enzim utilitzant mannitol o glucosa com a font de
carboni en discontinu i discontinu alimentat. En l’operació en discontinu alimentat van ser
necessàries dues addicions de glucosa per assolir els mateixos nivells de producció que amb una
addició de mannitol.Recombinant protein production on industrial scale requires varied and efficient expression systems. Gram-positive bacteria such as Streptomyces, may be an alternative since proteins are secreted through the medium. The sequence of the genome of several Streptomyces species and their post-genomic analysis has allowed to determine and characterize the secretion machinery. Two secretion pathways are mainly use in Streptomyces: Sec pathway and Tat pathway. Protein precursors contain type I signal peptide that allows a proper translocation though membrane and whose sequence determines which pathway must be used in order to export each protein. During its translocation, type I signal peptidases (SPases) cleave the signal peptide leading the secretion of the mature protein through the medium. Previous studies on the secretory machinery have described four signal peptidases in Streptomyces lividans (SipW, SipX, SipY and Sip Z) and they have postulate SipY as the one which develops the main role in protein secretion. SipY deficient strain has a secretion ability significantly affected but, paradoxically, it is a good host for the protein overproduction since it has a considerably reduced protease activity. In this work, we have studied the production of agarase and laccase in SipY- strain (S. lividans ΔsipY) in a bioreactor scale to assess whether this strain can be considered as a host for the production of recombinant proteins in the industry. These two proteins are mainly secreted by Tat pathway. Firstly, agarase from S. coelicolor A3(2) was cloned in a multicopy plasmid in S. lividans wild type strain and SipY- mutant strain (S. lividans TK21pAGAs5 and S. lividans ΔsipYpAGAs5). Batch cultures have been carried out and S. lividans ΔsipYpAGAs5 of which has presented better agarase production and it has been selected. Appropriated medium has been also selected operating in continuous. Secondly, focusing on laccase production, three strains have been constructed in which the homologous gene of S. lividans is regulated by three different promoters: its own promoter, the promoter of erythromycin resistance gene and the S. coelicolor agarase promoter. The strain in which the laccase gene is regulated by agarase promoter (S. lividans ΔsipYpFD-DagAplaccase) has been selected and studied in batch and fed-batch mode using mannitol or glucoses as carbon source. In fed-batch cultures, two glucose addition have been necessary to achieve the same production as unic mannitol addition.
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Gildenhuys, Carin. "Investigation of the role of the extracellular β-agarase, produced by the bacterial epiphyte Pseudoalteromonas sp. LS2i, in the virulence response towards the agarophyte Gracilaria gracilis." Doctoral thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/4266.
Full textAbstract:
Includes abstractIncludes bibliographical references
Gracilaria gracilis that grows naturally at Saldanha Bay, South Africa is economically important as a source of agar. The Gracilaria yields from natural beds at Saldanha Bay are however unreliable, and consequently the South African Gracilaria industry has experienced a number of setbacks over the years. The only way a consistent supply can be assured is by mariculture to supplement the natural harvests. In 1993 the Seaweed Research Institute (SRU) found that mariculture of G. gracilis in Saldanha Bay is feasible but that there is potential to improve yields by technical research and development (Anderson et al.1996a). Jaffray and Coyne (1996) developed a pathogenicity assay that demonstrated that agarolytic bacteria isolated from Saldanha Bay Gracilaria induced disease symptoms such as thallus bleaching, while non-agarolytic isolates did not. It is thought that unfavorable environmental conditions such as elevated water temperature and nutrient depletion, which occur during the summer months in the surface layers of the water column in Saldanha Bay, induce the onset of agarase production or result in changes in the bacterial community structure in which agarase-producers become more dominant. By using the pathogenicity assay, Jaffray and Coyne (1996) identified the highly agarolytic Gracilaria gracilis pathogen, Pseudoalteromonas sp. LS2i. The aim of this study was to characterize the bacterial pathogen, Pseudoalteromonas sp. LS2i to further our understanding of virulence regulation and specifically, the role of the agarase enzymes in the process of seaweed-pathogen interaction. Two agarolytic clones, pEB1 and pJB1, were obtained after constructing and screening a Pseudoalteromonas sp. LS2i genomic library in Esherichia coli. Restriction enzyme mapping suggested that both clones contain the same agarase gene. Southern hybridization studies confirmed the origin of the cloned DNA and sequencing studies revealed the 1062 bp ORF, putative promoter region, putative ribosome binding site and putative transcriptional start point of the cloned agarase gene. The ORF showed sequence identity to several other β-agarases and was identified as a member of the GH-16 family of glycoside hydrolases. The agarase was purified from the E. coli JM109 (pEB3) transformant. The molecular weight was estimated to be 39 kDa by SDS-PAGE. Zymogram analysis confirmed that the purified protein is agarolytic and TLC analysis revealed that the predominant end-products of agar hydrolysis are neoagarohexaose and neoagarobiose, which indicates the same mode of action as that observed for the agarase produced extracellularly by Pseudoalteromonas sp. LS2i.
Books on the topic "Agarases"
Book chapters on the topic "Agarases"
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Schomburg, Dietmar, and Margit Salzmann. "Agarase." In Enzyme Handbook 4, 435–38. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-84437-9_70.
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Macchiavello, Juan, Rosa Saito, Gracinda Garófalo, and Eurico C. Oliveira. "A comparative analysis of agarans from commercial species of Gracilaria (Gracilariales, Rhodophyta) grown in vitro." In Sixteenth International Seaweed Symposium, 397–400. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4449-0_47.
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"α-Agarase." In Class 3 Hydrolases, 170–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-85703-7_28.
Full textConference papers on the topic "Agarases"
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MUIZNIECE, Inga, and Daina KAIRISA. "FATTENING AND SLAUGHTER RESULTS ANALYSIS OF HEREFORD BREED BULLS BORN IN DIFFERENT SEASONS." In RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.198.
Full textAbstract:
The aim of this study was to explain the birth season effect on Hereford bulls fattening results. The research was made within the project ‘Baltic Grassland Beef’ framework in years 2015 and 2016. Data about 41 Herford purebred bull was used in the research, grown in different farms of Latvia. Bulls were slaughtered in certified slaughterhouse ‘Agaras’ (Lithuania). The average birth weight of the Hereford breed bulls was in border from 42.9 – 45.0 kg. The lowest birth weight was on spring season born bulls – 42.9 kg, but the highest on winter season born bulls - 45.0. Average realization age of bull’s, in the research groups, was on range from 567 days to 661 days. Bulls born on autumn and winter before slaughtering were significantly older, respectively 661 and 655 days with live weight of 519.9 kg un 542.1 kg. On spring born bulls with age 600 days reached the biggest live weight – 542.0 kg, respectively these group bulls average daily weight gain from birth to slaughter per day was the biggest among all the groups – 831.9 g. The highest slaughter weight showed on autumn and winter seasons born bulls, respectively 275.5 kg and 274.8 kg. In the research groups on different seasons born bulls conformation score was from points 2.4 to 2.6. All the bull’s carcass in the research groups were evaluated as 2nd and 3rd fat class. between the age before slaughter and average daily weight gain from birth to slaughter there is an important negative correlation (from r = -0.858 to = -0.977, p<0.05), except on spring season born bulls.