Production of Carbohydrate by the Marine Diatom Chaetoceros affinis var. Willei (Gran) Hustedt. III. Structural Studies of the Extracellular Polysaccharide.

THE COMPLEX POLYSACCHARIDES OF THE RAPHID DIATOM PINNULARIA VIRIDIS (BACILLARIOPHYCEAE)1

“…The quantity of polysaccharide recovered from the culture medium of log phase P. viridis was relatively low (approximately 0.6 mg·L −1 ). The amounts of polysaccharide recovered from diatom culture media can vary substantially depending on culture conditions (Allan et al 1972, Haug and Myklestad 1976) but are significantly higher from stationary phase cultures than from log phase cultures and can often exceed 20 mg·L −1 (Smestad et al 1974, Smith and Underwood 2000, de Brouwer and Stal 2002). The sugar composition of the polysaccharides solubilized in diatom culture media is highly variable for different species, making generalizations difficult.…”

“…The 6‐deoxysugars, Rha and/or Fuc, were major constituents (20–60% w/w) of polysaccharides recovered from the culture media of numerous pennate and centric diatoms, including Thalassiosira pseudonana (Hustedt) Hasle et Heimdal (as Cyclotella nana Hustedt), Navicula incerta Grunow, Asterionella socialis Lewin et Norris, Coscinodiscus wailesii Gran et Angst (as C. nobilis Grunow), and four Chaetoceros species (Allan et al 1972, Smestad et al 1974, 1975, Haug and Myklestad 1976, Percival et al 1980). Galactose and/or Xyl were also recovered in significant amounts from the culture media of several diatoms (Smestad et al 1974, 1975, Staats et al 1999, de Brouwer and Stal 2002). Xylose was the major sugar (46.1 mol%) of the polysaccharides solubilized in the culture medium of the pennate diatom, Cylindrotheca closterium (Ehrenberg) Reimann et Lewin (Staats et al 1999).…”

“…By contrast, the observation that the terminal, 3‐, and 3,6‐linked Gal p linkages were relatively enriched in the SCM only suggested that these Gal residues formed a separate polymer, possibly a partially 6‐substituted 3‐linked galactan. The media‐soluble sulfated polysaccharides of two species of the centric genus Chaetoceros were studied in detail because their yields were exceptionally high at stationary growth phase (16–40 mg·L −1 ) (Smestad et al 1974). Fucose, Rha, and Gal were essentially the only sugars in this fraction from Chaetoceros affinis var.…”

“…Fucose, Rha, and Gal were essentially the only sugars in this fraction from Chaetoceros affinis var. willei and C. curvisetus Cleve and occurred in approximate molar ratios of 7:8:5 and 10:1:3, respectively (Smestad et al 1974, 1975). Some 3‐linked Rha p was reported for the polysaccharide from C. affinis but was detected only at low levels, and Rha occurred predominantly as terminal and 2‐linked Rha p (Smestad et al 1974).…”

Cellular and extracellular production of carbohydrates and amino acids by the marine diatom Skeletonema costatum: diel variations and effects of N depletion

“…Extracellular polysaccharides are generally complex heteroglycans (Smestad et al 1974, 1975, Percival et al 1980, and often form viscous or gelatinous mucilages. The next largest extracellular fraction may be proteins and amino acids, and other important substances are organic acids, sugar alcohols, lipids and fatty acids, vitamins and toxins.…”