Extracellular Matrix Assembly in Diatoms (Bacillariophyceae) (I. A Model of Adhesives Based on Chemical Characterization and Localization of Polysaccharides from the Marine Diatom Achnanthes longipes and Other Diatoms)

Abstract

Extracellular adhesives from the diatoms Achnanthes longipes, Amphora coffeaeformis, Cymbella cisfula, and Cymbella mexicana were characterized by monosaccharide and methylation analysis, lectin-fluorescein isothiocyanate localization, and cytochemical staining. Polysaccharide was the major component of adhesives formed during cell motility, synthesis of a basal pad, and/or production of a highly organized shaft. Hot water-insoluble/hot 0.5 M NaHC0,-soluble anionic polysaccharides from A. longipes and A. coffeaeformis adhesives were primarily composed of galactosyl (64-70%) and fucosyl (32-42%) residues. I n A. longipes polymers, 2,3-, f-, 3-, and 4-linked/substituted galactosyl, f-, 3-, 4-, and 2-linked fucosyl, and t-and 2-linked glucuronic acid residues predominated. Adhesive polysaccharides from C. cistula were EDTAsoluble, sulfated, consisted of 83% galactosyl (4-, 4,6-, and 3,4-linked/substituted) and 13% xylosyl (t-, 4,/5,-, and 3,-linked/ substituted) residues, and contained no uronosyl residues. Ulex europaeus agglutinin uniformly localized cu(l,2)-~-fucose units in C. cistula and Achnanthes adhesives formed during motility and in the pads of A. longipes. D-Calactose residues were localized throughout the shafts of C. cisfula and capsules of A. coffeaeformis. D-Mannose and/or o-glucose, D-galactose, and a(t)-i-fucose residues were uniformly localized in the outer layers of A. longipes shafts by Cancavalia ensiformis, Abrus precatorim, and Lotus tefragonolobus agglutinin, respectively. A model for diatom cell adhesive structure was developed from chemical characterization, localization, and microscopic observation of extracellular adhesive components formed during the diatom cell-attachment process.Achnanthes longipes, Cymbella cistula, Cymbella mexicana, and Amphora cofeaeformis are relatively large, fast-growing, unicellular organisms specialized in cell motility and attachment via distinct extracellular structures. These adhesive structures can be easily manipulated, observed, and isolated for the study of synthesis, transport, modification, and assembly of extracellular polymers. Modeling such systems can provide a better understanding of how plant cells adhere to surfaces and interact with their surrounding environments. Furthermore, these diatoms are a major component of marine and freshwater biofilms (Round et al., 1990) and thus cause a variety of biofouling problems (Alberte et al., 1992). Understanding how these cells adhere to surfaces will also aid in the development of new antibiofouling surfaces and of adhesives for use in marine and freshwater environments.Most diatoms attach to surfaces via polymers excreted from a slit (raphe) or apical pore field in the siliceous cell wall (frustule) (Hoagland et al., 1993). Exuded polymers are assembled into a variety of structures, such as trails (material left behind during motility), sheaths (organic matrices tightly associated with the cell wall), capsules (organic matrices loosely associated with the cell walls), and stalks (permanent attachment s...

The glucans extracted with warm water from diatoms are mainly derived from intracellular chrysolaminaran and not extracellular polysaccharides

“…Cell disruption was often assisted by lyophilization of the diatoms or, in the study of chrysolaminaran from P. tricornutum, by pulverizing frozen cells (Ford & Percival, 1965). Compositional and structural analyses confirmed that chrysolaminaran was the dominant component extracted by these methods (Ford & Percival, 1965;Handa, 1969;Handa & Tominaga, 1969;Handa & Yanagi, 1969;Myklestad & Haug, 1972;Smestad Paulsen & Myklestad, 1978;Wustman et al, 1997).…”

“…willei), Chaetoceros sp., Skeletonema costatum and Stauroneis amphioxys (Ford & Percival, 1965;Handa & Yanagi, 1969;Myklestad & Haug, 1972;Smestad Paulsen & Myklestad, 1978;McConville et al, 1986). More recently, linkage analyses of water extracts obtained during sequential extraction of Achnanthes longipes (Wustman et al, 1997) and Pinnularia viridis (Chiovitti et al, 2003) yielded 1,3-linked glucopyranose (Glcp) as the dominant component.…”

“…The methods used to extract diatom chrysolaminaran generally involved cell disruption by treatment with dilute H 2 SO 4 (Myklestad & Haug, 1972;Va˚rum & Myklestad, 1984;Va˚rum et al, 1986;Granum & Myklestad, 1999 or extensive extraction with water at or near boiling temperature (Handa, 1969;Handa & Tominaga, 1969;Handa & Yanagi, 1969;Hama & Handa, 1992;Wustman et al, 1997). Cell disruption was often assisted by lyophilization of the diatoms or, in the study of chrysolaminaran from P. tricornutum, by pulverizing frozen cells (Ford & Percival, 1965).…”

“…Although diatom extracellular polysaccharides are unique compared with those of other algae and land plants, their structures are poorly understood and generalizations are difficult. They are usually heterogeneous, comprising hexoses, pentoses, 6-deoxyhexoses, Nacetylaminosugars, and/or O-methylated sugars, and acidic, with uronic acids and/or sulphate esters (for review see Hoagland et al, 1993;Wustman et al, 1997Wustman et al, , 1998McConville et al, 1999;Chiovitti et al, 2003).…”

Progress of marine biofouling and antifouling technologies

“…As with bacteria, EPS produced by different types of diatoms are diverse [49,50], and include various protein fractions and complex anionic polysaccharides with heterogeneous combinations of monosaccharide [45]. In addition, at least two types of mucilage can be detected for the same species of diatom [51,52].…”