It is well known that cellulose is assembled by specialized enzyme complexes (known as terminal complexes = TCs) located on or within the plasma membrane.At least three types of TCs have been described: a single linear row of particles observed in the brown alga Pelvetia; linear multiple rows in Oocystis and in some green algae; and, hexagonally arranged particle “rosettes” in some algae and solitary rosettes in all land plants. A new linear type of TC has been found in a freshwater xanthophycean alga Vaucheria hamata. Fine structure of the TC has been analyzed by high resolution analytical techniques for freeze-replication. Further examination for its characteristics was carried out by the treatment with inhibitors for cellulose formation(2,6-dichlorobenzonitrile, DCB) and its crystallization (Tinopal LPW).v. hamata was cultured under appropriate light conditions and single cells were cut into small pieces and recultured for two days. They were plasmolyzed in 0.2M NaCl, washed with fresh medium, and then recultured with or without inhibitors for 4-10 h. The cells were placed on Balzers double replica supports and quickly frozen in liquid propane. The supports were inserted in a Balzers double replica holder cooled by liquid nitrogen and placed in the chamber of a Balzers BA 360. Cells were fractured at 2x10-4 Pa and etched for 1 min. Most of the specimens were rotary shadowed (1 rps) with Pt-C at an angle of 30° and coated with carbon. Replicas were cleaned with 50% sulfuric acid containing 5% sodium dichromate and distilled water, and observed at 80Kv on a Philips EM 420.
Evidence for an intramembrane component associated with a cellulose microfibril-synthesizing complex in higher plants.