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MICROARCHITECTURE AND ENVELOPE DEVELOPMENT IN DYSMORPHOCOCCUS GLOBOSUS (PHACOTACEAE, CHLOROPHYCEAE) 1
Author(s) -
Porcella Russell A.,
Walne Patricia L.
Publication year - 1980
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.1980.tb03032.x
Subject(s) - biology , ultrastructure , chlorophyceae , envelope (radar) , biophysics , mucilage , botany , cell envelope , transmission electron microscopy , layer (electronics) , algae , microbiology and biotechnology , materials science , chlorophyta , biochemistry , composite material , nanotechnology , telecommunications , radar , escherichia coli , computer science , gene
The ultrastructure and development of the envelope (lorica) of Dysmorphococcus globosus Bold & Starr are described. This is the first detailed characterization of the envelope of a member of the Phacotaceae. The general ultrastructure and cellular organization of the protoplast are similar to that reported for other volvocalean algae. Transmission electron microscopy (TEM) showed the granular and fibrous components of the immature envelope, the sequential deposition of a mineralized layer, and the presence of perforations in the mineralized layer. Iron is incorporated in the mineralized envelope with 55 Fe labeling. Experiments with 59 Fe showed an 86% uptake of available iron by cells in culture, with the label localized to the envelope and envelope‐associated mucilage. Envelope formation is the result of the following phenomena: i) secretion of an immature envelope consisting of an outer fibrous layer and an inner granular layer; ii) sequential precipitation of a mineralized component in the inner layer, during which time pores are formed as part of the developmental process; iii) exudation of mucilaginous materials through those pores; iv) localized secretion and subsequent retention of the secretory product giving rise to the pebbled nature of the envelope surface. In living cells, the envelope surface is coated with mucilaginous secretory products that obscure the pores, which were previously reported to be lacking in this species. Results of acetolysis on aplanospores suggest the presence of a sporopollenin in D. globosus .