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Chemical Composition and Biochemistry of Sea Ice Microalgae
Published in Rita A. Horner, Sea Ice Biota, 1985
The major reserve carbohydrates characteristically synthesized by different ice taxa are shown in Table 3. The principal reserve polysaccharide in diatoms is chrysolaminarin, which has been extracted and characterized from a number of diatom species. It is also an important polysaccharide in three sea ice diatoms that have been examined, Navicula glaciei, Stauroneis amphioxys, and Nitzschia sp.31 Structural investigations show that chrysolaminarin contains only glucose which is (1→3)-β-d-linked, with some branching through C(0)6.96,98 Chrysolaminarin extracted from Skeletonema costatum contained, in addition, branching at C(0)2 which has not been previously observed in algal reserve polysaccharides.98 Chrysolaminarin differs from laminarin produced by brown algae (Phaeophyceae) in lacking terminal mannitol groups and having a shorter average chain length.96 It is readily extracted from cultured diatoms or natural populations with dilute acid and constitutes from 4 to 80% of the organic dry matter.21 Chrysolaminarin is also the main storage reserve carbohydrate in the Chrysophyceae99 and has been tentatively identified in the Prymnesiophyceae on the basis of cytochemical reactions.100
Microalgae I: Origin, Distribution and Morphology
Published in Arun Kumar, Jay Shankar Singh, Microalgae in Waste Water Remediation, 2021
Chromophyta are a highly diverse group, which includes golden, golden brown, brown or yellow-green colored algae rather than the grass-green, blue-green or red coloration typical of other major algal divisions. This division also includes diatoms, coccolithophorids and silicoflagellates, which are quite distinct microalgal classes in an ecological and morphological manner (Van den Hoek et al. 1994). They have some characteristic features: (a) the presence of a common storage product chrysolaminarin (a β-linked glucan); (b) preponderance of carotenes over chlorophylls. Some chromophytes and prymnesiophytes also store fats and oils to synthesize paramylon, which is quite often present in euglenoids.
Nuisance mucilage produced by Lindavia intermedia (Bacillariophyceae) in New Zealand lakes
Published in Inland Waters, 2022
Phil M. Novis, Tracey J. Bell, Putri Fraser, Cara A. Luiten, Simon F. R. Hinkley, Hugo Borges, Marc Schallenberg
We observed variation in the visual and cohesive properties of lake snow from different lakes, depths, and seasons. In particular, lake snow varied greatly in its adherence to the fishing line following snow tows, suggesting that the material varies in its adhesiveness, although no statistically significant difference in relative yield from tows compared to the pump method at different times was detected (Fig. 3a). Adhesiveness of particles is a quantity known as ɑ, a well-studied parameter that should relate to the adhesiveness of lake snow particles to the tow line. Chitin, which is neither sticky nor soluble (Kumar 2000), is unlikely to affect this property. Laboratory methods to measure ɑ have been developed (Jackson 1990, Kiørboe et al. 1990, Kiørboe 1997, 2001) but would be difficult to implement in our study, especially when cell populations occur at relatively low densities and the material changes quickly after collection. Understanding the adhesiveness of lake snow is important because it is an aspect of the nuisance factor of lake snow. The adhesive factor of lake snow is not known but may be due to polysaccharides other than chitin, perhaps containing uronic acids and sugars with sulphate groups, both of which are thought to confer adhesive properties (e.g., Staats et al. 1999). The monosaccharide composition (including the acidic uronic acids) of the EPS has been investigated in numerous diatoms and varies considerably among species (Hoagland et al. 1993). Our investigation of the water recovered from washing 2 samples of lake snow from the mesh from pump collections in winter indicated the presence of sugars other than glucosamine (from chitin), including glucuronic acid. The diversity of the monosaccharides detected suggests more than one type of polysaccharide and cannot solely comprise chrysolaminarin (a glucose polysaccharide) released by cell lysis. Interestingly, the capsule of L. intermedia, which surely contains hydrated polysaccharides with different qualities from the rigid, crystalline, chitin fibrils (Gügi et al. 2015), has been observed to increase at the start and decrease at the end of a summer season (M. Joubert, Seattle Public Utilities, pers. comm., 2017). Thus, although the origin of the non-chitinous polysaccharide found in the wash water from our samples could not be confirmed, at least some is likely of extracellular origin. The chitin fibrils may become coated with stickier, hydrated polysaccharide as a result of greater capsule synthesis in summer, and/or the coating polysaccharides may be reduced by decomposition as the particles age, generating the observed variation in properties.