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Structural and Functional Diversity of Acidic Polysaccharides from Various Species of Coocolithophorid Algae)
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... Three CAPs are involved in the complex regulation of coccolithogenesis in Pleurochrysis carterae 9 as opposed to one in Emiliania huxleyi 6 . Their biochemical composition has also been shown to vary across species 10 and morphologically distinct strains of E. huxleyi 6,11 . In fact, this property was successfully exploited for antisera production that have been used for classifying E. huxleyi morphotypes A and B 12 . ...
... Since the migration pattern of the CAPs is identical during PAGE and SDS-PAGE analysis (Supplementary Fig. 2) we can conclude that the observed migration pattern of CAPs during PAGE-analysis is not affected by their charged (sulfonic and uronic acid) residues. Therefore, there is a true difference in the size of our isolated CAPs, which concurs with previous reports 6, 10 . CAPs from cultured and fossil samples were also subjected to reverse-phase high-performance liquid chromatography (RP-HPLC) to confirm their identity as acidic polysaccharides ( Supplementary Fig. 3a). ...
Unicellular phytoplanktonic algae (coccolithophores) are among the most prolific producers of calcium carbonate on the planet, with a production of B10 26 coccoliths per year. During their lith formation, coccolithophores mainly employ coccolith-associated polysaccharides (CAPs) for the regulation of crystal nucleation and growth. These macromolecules interact with the intracellular calcifying compartment (coccolith vesicle) through the charged carboxyl groups of their uronic acid residues. Here we report the isolation of CAPs from modern day coccolithophores and their prehistoric predecessors and we demonstrate that their uronic acid content (UAC) offers a species-specific signature. We also show that there is a correlation between the UAC of CAPs and the internal saturation state of the coccolith vesicle that, for most geologically abundant species, is inextricably linked to carbon availability. These findings suggest that the UAC of CAPs reports on the adaptation of coccolithogenesis to environmental changes and can be used for the estimation of past CO 2 concentrations.
... It has been proved that polysaccharides, such as chitin, hyaluronic acid, and keratan sulfate, play an important role in the processes of biopolymerization. It has been shown that polysaccharides, mainly consisting of residues of galacturonic, glucuronic, and mannuronic acids [115,116], are strong inhibitors of CaCO 3 deposition [117], and participate in the formation of crystal morphology [118]. Alginates, linear polysaccharides consisting of monomeric units of mannuronate and guluronate [118], can form complexes with the Ca 2+ ion and participate in the formation of hydrogels and in the subsequent formation of calcium carbonate deposits on the cell walls of brown algae. ...
In this paper, we consider natural and modified polysaccharides for use as active ingredients in scale deposition inhibitors to prevent the formation of scale in oil production equipment, heat exchange equipment, and water supply systems. Modified and functionalized polysaccharides with a strong ability to inhibit the formation of deposits of typical scale, such as carbonates and sulfates of alkaline earth elements found in technological processes, are described. This review discusses the mechanisms of the inhibition of crystallization using polysaccharides, and the various methodological aspects of evaluating their effectiveness are considered. This review also provides information on the technological application of scale deposition inhibitors based on polysaccharides. Special attention is paid to the environmental aspect of the use of polysaccharides in industry as scale deposition inhibitors.
... Such unstable phase of vaterite may be a main factor to form the petallike patterns. It was reported that aragonite was dissolved by the local pH decrease, and vaterite was deposed in the presence of a large quantity of saccharide [37]. The solubility of aragonite or vaterite in the water is different. ...
Iron and steel slag (ISS) is a byproduct of iron refining processes. The lack of iron in seawater can cause barren grounds where algae cannot grow. To improve the barren grounds of the sea, a supply of iron to the seawater is necessary. This study focused on bacteria interacting with ISS and promoting iron elution in seawater. Sulfitobacter sp. (TO1A) and Pseudomonas sp. (TO1B) were isolated from Tokyo Bay and Sagami Bay. The co-culture of both bacteria promoted more iron elution than individual cultures. After the incubation of both bacteria with ISS, quartz and vaterite appeared on the surface of the ISS. To maintain continuous iron elution from the ISS in the seawater, we also isolated Pseudoalteromonas sp. (TO7) that formed a yellow biofilm on the ISS. Iron was eluted by TO1A and TO1B, and biofilm was synthesized by TO7 continuously in the seawater. The present research is expected to contribute to the improvement of ISS usage as a material for the construction of seaweed forests.
... In the crayfish gastrolith, proteoglycans such as dermatan-, chondroitin-and keratin-sulfate glycosaminoglycans closely associate with the inorganic calcium carbonate phase (Fernandez et al., 2012).Chitin and chitosan, two naturally abundant biopolymers, regulate the assembly of mineral frameworks in crustacean shells, carapaces, and mollusk shells(Arias and Fernandez, 2008). In coccolithophorids, polysaccharides consisting of galacturonic, glucuronic and mannuronic acid residues(Kayano & Shiraiwa, 2009;Ozaki et al., 2007) are strong inhibitors of CaCO 3 precipitation(Marsh & Dickinson, 1997;Marsh et al., 1992;Ozaki N., 2004) and modulate the morphology of corresponding crystals(Borman et al., 1982;Dejong et al., 1976;Young et al., 1999). Precipitation of calcium carbonate on the cell wall surface of brown algae appears to be directed by alginates, linear polysaccharides composed of mannuronate and guluronate monomer units(Kloareg & Quatrano, 1988). ...
... 32 Vaterite was formed in the presence of acidic polysaccharides extracted from P. carterae in an in vitro precipitation experiment. 33 Whether the presence of vaterite is a consequence of this specific strain of P. carterae or the growth conditions cannot be definitively answered. ...
We have measured infrared spectra from several types of calcite: chalk, freshly cultured coccoliths produced by three species of algae, natural calcite (Iceland Spar) and two types of synthetic calcite. The most intense infrared band, the asymmetric carbonate stretch vibration, is clearly asymmetric for the coccoliths and the synthetic calcite prepared using the carbonation method. It can be very well fitted by two peaks: a narrow Lorenzian at lower frequency and a broader Gaussian at higher frequency. These two samples both have a high specific surface area. Density functional theory for bulk calcite and several calcite surface systems allow for assignment of the infrared bands. The two peaks that make up the asymmetric carbonate stretch band come from the bulk (narrow Lorenzian) and from a combination of two effects (broad Gaussian): the surface or near surface of calcite and line broadening from macroscopic dielectric effects. We detect water adsorbed on the high surface area synthetic calcite, which opens up for observing the chemistry of thin liquid films on calcite using transmission infrared spectroscopy. The combination of infrared spectroscopy and density functional theory also allowed us to quantify the amount of polysaccharides associated with the coccoliths. The amount of polysaccharides left in chalk, demonstrated to be present in other work, is below the IR detection limit, which is 0.5% by mass.
... Chitin and chitosan, two naturally abundant biopolymers, seem to regulate the assembly of mineral frameworks in crustacean shells, carapaces, and mollusk shells (Arias & Fernandez, 2008). Polysaccharides from coccolithophorids, mainly consisting of galacturonic, glucuronic and mannuronic acid residues (Ozaki et al., 2007;Kayano & Shiraiwa, 2009), were shown to be strong inhibitors of CaCO 3 precipitation (Marsh et al., 1992;Marsh & Dickinson, 1997;Ozaki et al., 2004) and modulate the morphology of corresponding crystals (Dejong et al., 1976;Borman et al., 1982;Young et al., 1999). Precipitation of calcium carbonate on the cell wall surface of brown algae appears to be directed by alginates, linear polysaccharides composed of mannuronate and guluronate monomer units (Kloareg & Quatrano, 1988), which can strongly interact with divalent cations such as Ca 2þ by a so-called 'egg-box' binding motif (leading to stable hydrogels at sufficiently high Biomineralization and biomimetic materials concentrations) (Fang et al., 2007). ...
: The present study aims to elucidate the effects of different carbohydrates on the early stages of calcium carbonate mineralization by following a systematic potentiometric titration-based approach. Distinct mono-, oligo- and polysaccharides were evaluated with respect to their influence
on the formation of solute pre-nucleation clusters, the nucleation process itself, and the solubility of the initially precipitated phase. By assaying 29 carbohydrates, we show that sugar stereochemistry, polarity, presence of Ca2+ binding sites, as well as the nature of glycosidic
linkages can play an important role in the interactions between the additives and the mineral species occurring in the course of CaCO3 crystallization from solution.
The advancement of reverse osmosis (RO) technology in water treatment has brought about significant purification benefits. However, the presence of scales poses obstacles to the long-term effectiveness and reliability of RO systems, therefore, the use of antiscalants has emerged as an effective solution. This comprehensive review explores various aspects of scale formations, including their characteristics and prevalence. It delves into detailed understanding of crystal nucleation inhibition, dispersion of crystal growth, threshold inhibition, and inhibition mechanisms, shedding light on the intricate processes involved in successful scale prevention. In addition, this review also explores the realm of antiscalants, uncovering their exceptional potential, mechanisms of action, and game-changing value in RO systems. It takes a thorough evaluation approach to different antiscalant substances, ranging from traditional inhibitors like phosphonates and synthetic polymers to more sustainable and greener inhibitors including biopolymers as promising candidates. The review assesses their efficacy, optimal dosage requirements, and compatibility with varying water pH levels. Moreover, the review highlights the utility of fluorescent-labeled antiscalants to elucidate the mechanisms underlying scale formation and inhibition, revealing the role of “nanodust” particles as primary heterogeneous nucleation centers, and the antiscalants’ role in disrupting the scale formation process. Limitations of current antiscalants and practical challenges, such as antiscalant-induced membrane biofouling, are also highlighted. Furthermore, the review explores options for removing antiscalants from the resulting concentrates. By setting the stage for future antiscalant research, this review offers innovative solutions to overcome existing challenges and achieve higher efficiency in RO systems, emphasizing the important role of synthetic and green polymers as antiscalants.
The coccolithophorids are unicellular marine algae belonging to the Haptophytawhich have calcified scales, coccoliths, on their surface. These algae play an importantrole in maintaining the global carbon pool of the marine ecosystem, not only as a primaryproducer in the food chain, but also as a producer of CaCO3. Being different from otherbiomineralization systems, their biomineralization system has the unique characteristic ofbeing intracellular. The mechanisms involved have been investigated mainly in thegenera Emiliania and Pleurochrysis, which are included in the two separate phylogeneticlineages of the coccolithophorids. Acidic polysaccharides, which are present in thecoccoliths, are considered to be involved in the coccolith formation. The structures andlocalization of acidic polysaccharides have been analysed in the two genera. However,the molecular mechanisms underlying the coccolith formation by coccolithophoridsremain unclear. Recently, analyses of EST and genome sequences, and involving cDNAarrays have been started in E. huxleyi and P. haptonemofera. The morphological,biochemical, and molecular biological studies on the calcification of thecoccolithophorids are reviewed, focusing on Pleurochrysis and Emiliania.
Our results demonstrate that in addition to being used for controlling morphology during calcite growth, polysaccharide (PS) that has been designed for biomineralization is also extremely robust, influencing calcite reactions even after millions of years. We investigated calcite (CaCO3) behavior in solutions with very small concentrations of PS that was produced similar to 70 Ma ago by coccolithophorids. We used atomic force microscopy (AFM) and the constant composition method to monitor calcite growth in the presence of this ancient PS. The ancient PS is still very active and has a high affinity for calcite step edges. Adsorption, even at extremely low concentrations (0.5 mu g/mL), results in decreased growth rate and dramatic morphology changes during growth and dissolution. The experimental results are complemented with surface complexation modeling for adsorption of components of polysaccharide from a modern coccolithophorid, Emiliania huxleyi. We generated surface complexation constants for the branch components: malonate: 14.25 +/- 0.17, succinate: 11.91 +/- 0.06, tricarballylate: 14.86 +/- 0.04, and citrate: 15.25 +/- 0.04. The implication is that complex PS could hold promise for smart material engineering and for preventing scaling.
COCCOLITHS, the calcite plates formed by unicellular phyto-planktonic
algae (coccolithophores, phylum Prymnesiophyta)1, are
produced in enormous quantities and probably constitute the largest
single carbonate sink in oceanic biogeochemical cycles. They are major
sediment formers, are of great value to geologists as biostratigraphic
indicators and have been extensively studied as models for
biomineralization2,3. We have applied the understanding of
coccolith biomineralization to the fossil record4 and present
evidence from electron and optical microscopy that there has been a
conserved mechanism of crystal nucleation throughout the 230 million
year history of coccolithophores. This fundamental feature of coccolith
growth, which we term the V/R model, involves the assembly of a ring of
single crystals with alternating orientations, radial (R) and vertical
(V), and provides a powerful tool for tracing phylogenies, identifying
homologous structures and rationalizing the higher taxonomy of the
group. The living cocco-lithophorid, Emiliania huxleyi, seemed anomalous
because only R crystals had been observed; transmission electron
microscopy of proto-coccolith rings, however, revealed relict V crystals
which are overgrown by preferential development of R units in complete
coccoliths. A speculative model based on a plicated macromolecular
template is presented as a possible explanation for the conserved
nucleation process.
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Sinking rates of several marine diatoms and flagellates from growing cultures, and from older cultures no longer growing, have been measured using a fluorometer to detect chlorophyll fluorescence of cells as they settled. Sinking rates were related to cell diameter, with cells from nongrowing cultures sinking about four times faster than cells from growing cultures. In Thalassiosira fluviatilis sinking rate was increased by the formation of cell aggregates, probably due to chitin fibers produced by the cells. Calculations of cell density were carried out using a modified Stokes equation that included effects of cell shape and orientation during sinking. The calculated density difference between cells from growing and non-growing cultures exceeded the differences expected if a breakdown of cell ionic regulation took place when growth ceased and may represent formation of aggregates. Composition of the culture media influenced sinking rate. In von Stosch's medium and, we suspect, in nature, a fraction of the cells are neutrally buoyant.The fluorometer method for measuring sinking rate appears to be suitable for use on board ship, but the high cell concentration required would restrict its use to phytoplankton blooms.
Coccoliths are delicate calcified structures produced by marine unicellular algae. In the species Emiliania huxleyi the calcium carbonate (mostly calcite) is closely associated with a complex, acidic polysaccharide which binds calcium ions specifically, interferes with the in vitro crystallization of calcium carbonate, and appears to be bound to a positively charged protein before the crystallization process is finished. Ultra-high resolution electron microscopy of the coccoliths reveals that the crystallographic structure differs in different parts of the constituent calcite elements. The synthesis of the coccoliths takes place intracellularly, and when this process is ended the coccoliths are extruded and incorporated into the so-called coccosphere surrounding the cell. Transmission electron microscope studies reveal the localization of polysaccharides in the calcifying organelle by means of cytochemical staining technique. The results are combined in a putative scheme describing coccolithogenesis.
Many mineralizing organisms selectively form either calcite or aragonite, two polymorphs of calcium carbonate with very similar
crystalline structures. Understanding how these organisms achieve this control has represented a major challenge in the field
of biomineralization. Macromolecules extracted from the aragonitic shell layers of some mollusks induced aragonite formation
in vitro when preadsorbed on a substrate of β-chitin and silk fibroin. Macromolecules from calcitic shell layers induced mainly
calcite formation under the same conditions. The results suggest that these macromolecules are responsible for the precipitation
of either aragonite or calcite in vivo.
In May-July 1955 a remarkable discoloration of the fjord and coastal waters in western Norway occurred. The phenomenon is attributed to an enormous concentration of the calcareous flagellate Coccolithus huxleyi, which was recorded in numbers up to 115 million cells per litre. Hydrographical and meteorological data from the areas concerned are presented and the possible causes of the irregular bloom of C. huxleyi are discussed. It would appear that a great influx of Atlantic water into the fjords caused a renewal and refertilization of the surface layers. This situation was favourable for an extraordinary plankton bloom, and the tentative conclusion is drawn that intensive illumination acted selectively on the species composition.
Soluble proteins in the scallop (Patinopecten yessoensis) foliated calcite shell layer were characterized using biochemical
and molecular biological techniques. SDS PAGE of these molecules revealed three major protein bands, 97 kD, 72 kD, and 49
kD in molecular weight, when stained with Coomassie Brilliant Blue. Periodic Acid Schiff staining and Stains-All staining
indicated that these proteins are slightly glycosylated and may have cation-binding potential. N-terminal sequencing of the
three proteins revealed that all three share the same amino acid sequence at least for the first 20 residues. A partial amino
acid sequence of 436 amino acids of one of these proteins (MSP-1) was deduced by characterization of the complementary DNA
encoding the protein. The deduced sequence is composed of a high proportion of Ser (31%), Gly (25%), and Asp (20%), typifying
an acidic glycoprotein of mineralized tissues. The protein has a basic domain near the N-terminus and two highly conserved
Asp-rich domains interspersed in three Ser and Gly-rich regions. In contrast with prevalent expectations, (Asp-Gly)n-, (Asp-Ser)n-,
and (Asp-Gly-X-Gly-X-Gly)n-type sequence motifs do not exist in the Asp-rich domains, demanding revision of previous theories
of protein-mineral interactions.