30 research outputs found
Structural Diversity in Galactans From Red Seaweeds and Its Influence on Rheological Properties
No full textGalactans are important components of many plant cell walls. Besides, they are the major polysaccharides in extracellular matrixes from different seaweeds, and other marine organisms, which have an acidic character due to the presence of sulfate groups in their structures. In particular, most of the red seaweeds biosynthesize sulfated galactans with very special linear backbones, constituted by alternating (1→3)-β-d-galactopyranose units (A-unit) and (1→4)-α-galactopyranose residues (B-unit). In the industrially significant seaweeds as source of hydrocolloids, B-units belong either to the d-series and they produce carrageenans (as in the order Gigartinales), or to the l-series, and they are sources of agarose and/or structurally related polymers (i.e., Gelidiales, Gracilariales). In both cases, the latter units appear as cyclized 3,6-anhydro-α-galactose in certain amounts, which can be increased by alkaline cyclization of α-galactose 6-sulfate units. Besides, it has been clearly shown that some red algae produce different amounts of both galactan structures, known as d/l-hybrids. It is not yet clear if they comprise both diasteromeric types of units in the same molecule, or if they are mixtures of carrageenans and agarans that are very difficult to separate. It has been reported that the biosynthesis of these galactans, showing that the nucleotide transport for d-galactopyranose units is UDP-d-Gal, while for l-galactose, it is GDP-l-Gal, so, there is a different pathway in the biosynthesis of agarans. However, at least in those seaweeds that produce carrageenans as major galactans, but also agarans, both synthetic pathways should coexist. Another interesting characteristic of these galactans is the important variation in the sulfation patterns, which modulate their physical behavior in aqueous solutions. Although the most common carrageenans are of the κ/ι- and λ-types (with A-units sulfated at the 4- and 2-positions, respectively) and usually in agarans, when sulfated, is at the 6-position, many other sulfate arrangements have been reported, greatly influencing the functional properties of the corresponding galactans. Other substituents can modify their structures, as methyl ethers, pyruvic acid ketals, acetates, and single stubs of xylose or other monosaccharides. It has been shown that structural heterogeneity at some extent is essential for the proper functional performance of red algal galactans.Fil: Ciancia, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Matulewicz, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Tuvikene, Rando. Tallinn University; Estoni
Complex sulfated galactans from hot water extracts of red seaweed Asparagopsis taxiformis comprise carrageenan and agaran structures
No full textHot water extraction from the red seaweed Asparagopsis taxiformis yielded three extracts which showed sulfated galactans with a D:L-galactose ratio non consistent with carrageenan or agaran backbones. The major extract was fractionated by cetrimide precipitation and redissolution with increasing sodium chloride concentrations due to their low solubility. Seven fractions were obtained, and studied by methylation analysis, desulfation-methylation, and NMR spectroscopy of the partially hydrolyzed and the native samples. Fractions with the highest yield were those obtained at high concentrations of NaCl. They comprised both agaran and crageenan structures in considerable amounts. The main agaran structures were β-D-galactose 4-sulfate and β-D-galactose 2-sulfate units linked to α-L-galactose 2,3-disulfate residues, and β-D-galactose linked to α-L-galactose 3-sulfate or 6-sulfate, or substituted with single stubs of β-D-xylose on C3, while the carrageenan structures comprised β-D-galactose (2-sulfate) linked to α-D-galactose 3-sulfate or 2,3-disulfate, and β-D-galactose 2,4-disulfate linked to α-D-galactose 2,3-disulfate. Between the less sulfated fractions, the one obtained by solubilization in 0.5 M NaCl was mainly constituted by agarans, which included 3,6-anhydro-α-L-galactose units. Anticoagulant activity was assayed by general coagulation tests (aPTT and TT), showing a moderate action compared with heparin. This is the first detailed study of the sulfated galactans from the order Bonnemaisoniales.Fil: Rodríguez Sánchez, Rodrigo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Saluri, Kadri. Tallin University; EstoniaFil: Tuvikene, Rando. Tallin University; EstoniaFil: Matulewicz, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Ciancia, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentin
Potential Antiviral Properties of Industrially Important Marine Algal Polysaccharides and Their Significance in Fighting a Future Viral Pandemic
No full textOver the decades, the world has witnessed diverse virus associated pandemics. The significant inhibitory effects of marine sulfated polysaccharides against SARS-CoV-2 shows its therapeutic potential in future biomedical applications and drug development. Algal polysaccharides exhibited significant role in antimicrobial, antitumor, antioxidative, antiviral, anticoagulant, antihepatotoxic and immunomodulating activities. Owing to their health benefits, the sulfated polysaccharides from marine algae are a great deal of interest globally. Algal polysaccharides such as agar, alginate, carrageenans, porphyran, fucoidan, laminaran and ulvans are investigated for their nutraceutical potential at different stages of infection processes, structural diversity, complexity and mechanism of action. In this review, we focus on the recent antiviral studies of the marine algae-based polysaccharides and their potential towards antiviral medicines
Kinetic behavior of the network structure changes in funoran gelation studied by rheological and NMR measurements
No full textFunoran is a promising food polysaccharide with unique gelling properties but understanding its gelation behaviors remains inadequate. This study aimed to investigate the influence of cooling and heating rates on funoran gelation properties and study its gelation mechanism by dynamic rheology and NMR studies. With constant heating rates, the melting point was unaffected by changing cooling rates, whereas higher cooling and heating rates enhance the gel strength and thermal hysteresis. The gelation kinetics mechanism of the funoran solution was elucidated at different quenching temperatures. The rheological measurement results indicated that the funoran solution quenched to lower temperatures resulted in higher G` in the gel state, and faster gelation rate compared with the solution quenched at higher temperatures. 1H NMR results revealed a slow decay in funoran signal intensity at higher temperatures (20 °C) and a fast signal decay at 2 °C. A theoretical model involving second and first-order reactions was proposed to describe the gelation kinetic process of funoran at different quenching temperatures. It was shown longer helix lengths were required for stable intermolecular association and gel formation at higher temperatures than at lower temperatures. These results offer valuable insights for optimizing the funoran gelation properties for various food applications
Fermentation optimization, purification and biochemical characterization of ι-carrageenase from marine bacterium Cellulophaga baltica
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Violating the confidentiality of corespodence, information in form of transmissions over a telecommunications netwoerk and other information
No full textAttīstoties komunikāciju tehnoloģijām un palielinoties informācijas aprites apjomiem, aizvien nozīmīgāka kļūst pārraidāmās informācijas aizsardzība.
Krimināllikuma 144.pantā noteikta atbildība par korespondences, pa telekomunikāciju tīkliem pārraidāmās informācijas un citas informācijas noslēpuma pārkāpšanu. Autore, analizējot Krimināllikuma 144.pantā ietvertā noziedzīgā nodarījuma attīstību Latvijas teritorijā, secina, ka atšķirībā no pašreizējās izpratnes par informācijas noslēpumu, sākotnēji netika aizsargāta jebkura pārraidāmā informācija, kā arī tika noteikta tikai pilsoņa korespondences aizsardzība. Izpētot Krimināllikuma 144.pantā ietvertā noziedzīgā nodarījuma sastāvu, autore skaidro jēdzienu informācija, korespondence, „pa telekomunikāciju tīkliem pārraidāmā informācija” un „cita informācija” saturu, kā arī sniedz to definīcijas.
Atslēgvārdi: informācija; korespondence; noslēpums; noziedzīgā nodarījuma sastāvs.Article 144 of the Criminal Law stipulates liability for violating confidentiality provision when information is given over by correspondence, transmitted over telecommunications networks or for violating confidentiality of other information. The author, when analyzing application of offense contained in Article 144 of the Criminal Law in Latvia over the years concludes that interpretation of the information confidentiality concept has changed and initially not all transmitted information was protected and protection was extended only to personal correspondence. Having examined the content of criminal offense included in Article 144 of the Criminal Law the author explains the term “information”, “correspondence”, “information transmitted over telecommunications networks” and “other information” as well as provides their definitions.
Keywords: information; correspondence; confidentiality;criminal offence
Optimizing the Processing of Shellfish (Mytilus edulis and M. trossulus Hybrid) Biomass Cultivated in the Low Salinity Region of the Baltic Sea for the Extraction of Meat and Proteins
No full textMussel farming is a novel and growing aquaculture field in the Baltic Sea. Nevertheless, there is very little published evidence on the processing of shellfish biomass in the region. The aim of this study is to develop a methodology for the extraction of organic-rich fractions from small-sized blue mussels of the Baltic Sea region that is applicable and economically viable for the feed and food industry. The efficiency of mussel meat separation was evaluated using different processing, drying, and filtration techniques. The laboratory experiments have succeeded in finding a method that is operationally feasible and does not require overly complex and expensive laboratory settings. These trials also showed that the separation of meat from fresh or frozen mussels can be achieved by simple crushing and sedimentation methods and the extraction yielded a significant amount of mussel meat (7.6%) with a high protein content (3.2%, i.e., half of the total protein found in the used mussel-mass). It also appeared that the use of filtration is not practical because the protein loss was extremely high. In addition, filtration makes the process of dry-matter separation more complex, and costs are unlikely to be compensated by the energy saved in drying
The contribution of microbial biotechnology to sustainable development in agriculture and allied sectors
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