Study on the oligosaccharides composition of the water-soluble fraction of marine mucilage by electrospray tandem mass spectrometry (original) (raw)
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Characterization of carbohydrates in mucilage samples from the northern Adriatic Sea
Analytical and Bioanalytical Chemistry, 2003
Carbohydrate contents in seawater, mucilage, and mucilage interstitial waters were analyzed during episodes of mucilage formation in the summers of 2000 and 2001 in the northern Adriatic Sea off Pesaro and in the Gulf of Trieste using 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH) and 2,4,6-tripyridyl-s-triazine (TPTZ) assays. The significant presence of polysaccharides in seawater in the presence of mucilage has an important impact on the agglomeration processes forming gelatinous material (macrogels). Characterization of oligosaccharides in the water-soluble fraction of mucilage using HPLC/RI revealed maltose and pentaose as the main components.
Chemosphere, 2001
The appearance of gelatinous aggregates called mucilages causes serious damages to tourism and ®shery industries of the Adriatic Sea. So, many studies have been planned and some of them are still in progress to clarify the origin and causes of the phenomenon. The scienti®c research has showed that mucilages are produced by several marine organisms when peculiar climatic and trophic conditions occur. Moreover, as far as the mucilage composition is concerned, although it is well known that polysaccharides give a high contribution, knowledge of the structural characteristics of mucilages and their relationship with the natural organic matter of the marine environment has not been clari®ed yet. In this paper a study on the characterization of the marine mucilage samples collected in the Adriatic and Tyrrhenian Seas is described. The study was performed by spectroscopic (infrared and colorimetric) techniques, and elemental analysis. The results showed that mucilage samples have chemical and structural similarities with the insoluble fraction of the marine humic substance (humin). According to experimental evidences it is possible to establish the relationship between mucilages and the dissolved organic matter (DOM) in the marine environment in order to identify the most likely pathways of mucilage formation.
Marine Chemistry, 2008
Benthic mucilaginous aggregates are frequently formed in various parts of the Mediterranean basin, as in the Tyrrhenian and Adriatic Seas. Notwithstanding their wide spatial distribution, the role played by these aggregates in the biogeochemical cycling of organic matter is still largely unknown.The characteristics of the benthic aggregates examined in the present study showed that they are different from other mucilaginous aggregates, such as the “pelagic” ones that can form in the same areas in the water column and subsequently sediment to the seafloor. The aggregates are usually formed of structures of the filamentous macroalgae Acinetospora crinita, Chrysonephos lewisii and Nematochrysopsis marina. The elemental composition of the aggregates showed a marine macrophyte origin on the basis of the bulk organic matter content of the aggregates. Carbohydrates and proteins account for 26.6 to 55.9% of the organic carbon in the mucilage, respectively. Monosaccharide composition of exopolysaccharides in the mucilage aggregates revealed a characteristic pattern, with galactose, xylose or mannose and fucose as the major components. The relatively high content of deoxysugars is another distinctive feature. The abundant sulphate and uronic groups present in the polysaccharides in addition to their macromolecular dimensions and elongation contribute to inter-chain aggregation. Electron microscopic observations suggest that the polysaccharide fraction is the main macromolecular component in the formation of the persistent gel network in the aggregates.
Composition and function of mucilage macroaggregates in the northern Adriatic
Aquatic Microbial Ecology, 2010
The episodic hyperproduction of mucilage macroaggregates in the northern Adriatic Sea creates an important site for the accumulation, transformation, and degradation of organic matter. In this review, the structure and function of macroaggregate components in relation to their macrogel and colloidal fractions are discussed. High resolution electron microscopy showed a very complex structure, a honeycomb-like structure of the mucus macroagregates that might grow to macroscopic sizes. The process of the formation and microbial interaction with the physicochemical diversity of the organic matter pool is poorly understood. Whether the in situ bacteria react to the carbohydrate-rich mucus as an imbalance in its C:N:P ratio or whether the mucus is in fact largely a bacterial construct in relation to high dissolved organic carbon levels is unknown. The majority of carbohydrate and protein macroaggregate pools are potentially degradable, while the great majority of lipids can be preserved in the water column and exported away or finally deposited on the seabed. Our present knowledge indicates that different macroaggregate fractions and components are subjected to compositional selective reactivity, with important implications for macroaggregate persistence. Future work should reconcile the discrepancies between bacterial ectoenzyme potential activities and biogeochemical degradation sequences based on actual measurements. The determination of biofilm architecture, particularly the spatial arrangement of microcolonies, has profound implications for the function of these complex communities. We need to improve our understanding of the dynamic relationship among bacteria, other microorganisms, and a variety of organic matter forms.
In the last two decades the presence and distribution of large aggregates in the Mediterranean Sea have encouraged to study the macromolecular features of dissolved organic matter and the implication of molecular characteristics of biopolymers on the aggregation processes. Monthly monitoring of marine carbohydrates in a coastal station of the Northern Adriatic sea during years 2001-2003 at 0.5, 10 and 15 m depth showed different pattern for dissolved and total carbohydrates in concurrence of the massive formation of aggregates. Since March to June 2004 marine water was collected for the partition experiment. The polysaccharide component was isolated by ultrafiltration. The monosaccharide compositions were very similar to those obtained from Adriatic pelagic mucilage. In June a significant reduction of the concentration of the low molecular weight polysaccharidic fraction was observed, in conjunction with the rapid increase of the high-molecular weight polysaccharides (HMW). In addition, the concentrations of deoxysugar (rhamnose and fucose) in the particulate matter decreased, and the fucose disappeared in June. These two monosaccharides and galactose may be considered bioindicators of the different degradation steps of marine polysaccharidic matter. This enrichment suggested that galactose-rich polysaccharides are able to undergo aggregate formation. Scanning electron microscopy and AFM imaging on extracted fractions showed the presence of fibrillar structures forming a highly branched tri-dimensional network similar to those found in Adriatic pelagic aggregates.
Analytical and Bioanalytical Chemistry, 2011
A simple and sensitive method was developed using hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry for determination of monosaccharides liberated from marine polysaccharides by acidic hydrolysis. Optimal separation of diastereomeric monosaccharides including hexoses, pentoses, and deoxyhexoses was achieved using an aminopropyl bonded column with mobile phase containing ternary solvents (acetonitrile/methanol/water) in conjunction with MS/MS in SRM mode. Mechanisms for fragmentation of deprotonated monosaccharides with regard to cross-ring cleavage were proposed. Matrix effects from coeluting interferences were observed and isotopic-labeled internal standard was used to compensate for the signal suppression. The method demonstrated excellent instrumental limits of detection (LOD), ranging from 0.7 to 4.2 pg. Method LODs range from 0.9 to 5.1 nM. The proposed method was applied to the analysis of polysaccharides in seawater collected from the open leads of the central Arctic Ocean in the summer of 2008.
Journal of Chromatography A, 1997
A method has been developed for determination of non-derivatised oligosaccharides by LC-MS at low concentration levels and in complex matrices of seawater and sediment pore water. Two ionisation techniques, dynamic fast atom bombardment (FAB) / liquid secondary ion (LSI) MS and electrospray ionization (ESI), were investigated and evaluated. The 1 electrospray using Li ions as adducts proved to be superior to the FAB / LSI-MS for the determination of non-derivatised oligosaccharides. The LC separation was accomplished by the use of a C column and the elution either by a gradient of 18 methanol-acetonitrile-water or pure water, in which latter case the column was held at an elevated temperature. We also report results from measurements of oligosaccharides in pore waters of marine sediment cores. Oligosaccharides of a range from 2 to 6 sugar units were found in a concentration range of 2-100 nM, the smaller sugars being more abundant. The depth profiles in the sediment cores indicate a production in the redox boundary layer and from there, diffusion in both directions to the overlaying water and further down into the sediment.
Marine Ecology Progress Series, 1997
During the massive mucllage event in the northern Adriatic Sea in July 1991 samples of macroaggregate were fixed in different ways: with formaldehyde, deep frozen and freeze-dried. Conventional microscopy (light and epifluorescence) revealed different autotrophic species embedded in gelatinous matl-ix. Cyanobacteria and heterotrophic bacteria were also identified. Scanning confocal laser microscopy (SCLMI and fluorescent m o l e c~~l a r probes (the lectins concanavalin A and UEA-I) showed wall-free cytoplasm and particulate polysacchar~des leaklng from the envelopes of broken cells in the matrix. The extensive cell lysis was supported by the observation of cytoplasn1-free cytoskeletons, stained by the molecular probe phalloidin High concentrations of triglycerides (30Y0 of total lipids) and free fatty aclds (22'2%) along with very low concentrations of phospholipids ( 2 % ) also indicated massive cell degradation in freeze-dried material. The mucllage observations were compared with those of a natural plankton community grown under hlgh nutrlent conditions using the same techniques. Free polysaccharides were observed as globular flocs (marine snow) during in situ enrichment experiments and inti-acellular polysaccharides as carbon storage materials In autotrophic organisms. No strings, filaments, layers, cell lysis or lipid classes indicating strong cell biodeterioration were observed in a 1 mo controlled experiment during a n algal bloom.
Applications of Mass Spectrometry to Structural Analysis of Marine Oligosaccharides
Marine Drugs, 2014
Marine oligosaccharides have attracted increasing attention recently in developing potential drugs and biomaterials for their particular physical and chemical properties. However, the composition and sequence analysis of marine oligosaccharides are very challenging for their structural complexity and heterogeneity. Mass spectrometry (MS) has become an important technique for carbohydrate analysis by providing more detailed structural information, including molecular mass, sugar constituent, sequence, inter-residue linkage position and substitution pattern. This paper provides an overview of the structural analysis based on MS approaches in marine oligosaccharides, which are derived from some biologically important marine polysaccharides, including agaran, carrageenan, alginate, sulfated fucan, chitosan, glycosaminoglycan (GAG) and GAG-like polysaccharides. Applications of electrospray ionization mass spectrometry (ESI-MS) are mainly presented and the general applications of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) are also outlined. Some technical challenges in the structural analysis of marine oligosaccharides by MS have also been pointed out.