Synthesis of Floridean Starch in the Red Alga Gracilaria Gracilis Occurs Via ADP-Glucose

Thin sections of the red alga, Lomentaria baileyana, a tubular member of the Rhodymeniales, were examined after permanganate fixation and Araldite embedding. Many of the cellular structures in Lomentaria were found to be similar to analogous structures in animals and higher plants. However, in the walls between cells are modified areas generally known as pits which are unique to the higher orders of red algae (Florideae). In this study the pits were found to consist of a plug-like structure surrounded by an uninterrupted membrane apparently continuous with the plasma membrane. Examination of the chromatophore revealed a characteristic limiting membrane, a relatively sparse distribution of plates, no grana, and a single disc apparently oriented parallel to the limiting membrane. In addition to their origin from non-lamellate proplastids, chromatophores were found capable of division by simple constriction. Floridean starch grains were observed outside the chromatophore and the possibility of an association of the first formed grains with portions of the endoplasmic reticulum is considered. Gland cells seem to have a high proportion of Golgi components (dictyosomes), and are believed to have some kind of secretory function. Many of the Golgi vesicles seem to open on the wall and presumably discharge their contents.

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Physiological Studies on Floridean Starch, Floridoside and Trehalose in a Red Alga, Serraticardia maxima

Shokubutsugaku Zasshi ◽

10.15281/jplantres1887.82.462 ◽

1969 ◽

Vol 82 (978) ◽

pp. 462-473 ◽

Cited By ~ 19

Author(s):

Hideyuki NAGASHIMA ◽

Hachiro OZAKI ◽

Saheye NAKAMURA ◽

Kazutosi NISIZAWA

Keyword(s):

Red Alga ◽

Floridean Starch ◽

Physiological Studies

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Cloning and characterization of a nuclear gene encoding a starch-branching enzyme from the marine red alga Gracilaria gracilis

Current Genetics ◽

10.1007/s002940050373 ◽

1998 ◽

Vol 34 (2) ◽

pp. 105-111 ◽

Cited By ~ 13

Author(s):

A. O. Lluisma ◽

M. A. Ragan

Keyword(s):

Nuclear Gene ◽

Red Alga ◽

Branching Enzyme ◽

Starch Branching Enzyme ◽

Gene Encoding ◽

Gracilaria Gracilis

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Observations on Cellular Structures of Porphyridium cruentum

The Journal of Cell Biology ◽

10.1083/jcb.5.2.289 ◽

1959 ◽

Vol 5 (2) ◽

pp. 289-294 ◽

Cited By ~ 55

Author(s):

Marcia Brody ◽

Albert E. Vatter

Keyword(s):

Electron Microscope ◽

Cellular Structure ◽

Red Alga ◽

Porphyridium Cruentum ◽

Cellular Structures ◽

Reserve Material ◽

Green Plants ◽

Cell Structures ◽

Floridean Starch ◽

Parallel Arrangement

The cellular structure of Porphyridium cruentum was studied with both light and electron microscope. The photosynthetic plastid in this red alga was found to be structurally similar to that in the Chlorophyceae and higher green plants. The phycobilins, as well as the chlorophyll, seem to be associated with the lamellae of the plastid. The pyrenoid, a region of low lamellar density, contains no tubules, and does not appear to function in synthesis or storage of reserve material. Grains of floridean starch are located in the cytoplasm, outside the plastid. Typical mitochondrial organelles were not observed. The nucleus is eccentric, and contains a nucleolus located on the inner face of the nucleus, nearest the plastid. The schedule for staining the nucleus is given in detail. Other cell structures (sheath, dictyosomes, etc.) are described. Growing cells in light of intensity leads to disruption of the parallel arrangement of the lamellar characteristic of cells grown in moderate light.

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