SOME CHEMOSYSTEMATIC ASPECTS OF THE AUDOUINELLA (ACROCHAETIUM‐RHODOCHORTON) COMPLEX

The total soluble protein, biliproteins, and esterase patterns from polyacrylamide discontinuous pH gel electrophoresis for three clones of Rhodochortoni purpureum and three identified species of Acrochaetium are described. Absorption spectra of biliproteins are presented. Interand intraspecific genetic affinities represented by electrophoretic protein patterns within the A udouinella (A crochaetium-Rhodochorton) complex are discussed. Problems of speciation within the complex are considered and the authors support the suggestions of Drew that a single genus be designated to represent the complex and the suggestion by Woelkerling that the genus Audouinella represent the sexually reproducing members of the complex. THE ACROHAETIUM-RHODOCHORTON complex of the Rhodophyta has been problematical to phycologists since the publication by Hamel (1928) of his monograph on the genera. Drew (1928, 1935) suggested that a single genus, Rhodochorton, represent the complex because of the lack of definitive characters in this group. Papenfuss (1945, 1947) supported the segregation of Acrochaetium from Rhodochorton on the basis of chloroplast morphology. While much work has been done on the comparative morphological expression of species in the complex (Knaggs, 1966, 1967; West, 1968, 1969, 1970; Woelkerling, 1971), no biochemical systematics have been attempted. Biochemical systematics have been applied to animals (Dessauer and Fox, 1964; Wilson et al., 1964), higher plants (Fox, Thurman, and Boulter, 1964; Boulter, Thurman, and Derbyshire, 1967; Thurman et al., 1967; Smith and Smith, 1970), mosses (Taylor, Schofield, and Elliott, 1970), and fungi (Clare, Flentje, and Ratkinson, 1968; Sorenson, Larsh, and Hamp, 1971) . Little application of this approach utilizing algae has been made (Derbyshire and Whitton, 1968; Young, 1970; Mallery and Richardson, 1971, 1972). This work was initiated on the 'Received for publication 16 April 1973. Sincere appreciation is offered to Dr. John A. West, Department of Botany. University of California, Berkeley, for cultures of Acrochaetium rhizoideum, A. pectinaturn, Rhodochorton concrescens and the three clones of R. purpureum. Dr. Michael J. Wynne, Department of Botany, University of Texas, Austin, provided an unidentified culture of Acrochaetium (W-1) isolated from the vicinity of Friday Harbor, Washington. This work was supported by NIH training grant HDO0187 to the Laboratory for Quantitative Biology, University of Miami. 2 Present address: Department of Environmental, Population and Organismic Biology, University of Colorado, Boulder 80302. premise that electrophoretic protein characters could provide systematic information on the affinities of the Acrochaetium-Rhodochorton complex. The purpose of the present study was to determine (1) if the segregation of Acrochaetium from Rhodochorton is valid from the standpoint of comparative protein biochemistry and (2) if the total soluble protein patterns are applicable to interspecific, intergeneric, or both categories of comparison. MATERIALS AND METHODS-Cultures used in the study were the following designates: A-5 = Acrochaetium rhizoideum; A-1 = A. pectinatum; R-2 = Rhodochorton purpureum (isolate from Alaska); R-3 = R. purpureum (isolate from Washington); R-6 = R. purpureum (isolate from Chile); 1413 = Acrochaetium sagraenum (Indiana University Culture Collection); and W-1 1 an unidentified species of Acrochaetium from Washington that is cytologically similar to A. pectinatum. Cultures A-5, A-1, R-2, R-3 and R-6 were kindly loaned for study by Dr. John A. West, Department of Botany, University of California, Berkeley. Culture W-1 was provided by Dr. Michael J. Wynne, Department of Botany, University of Texas, Austin. Cultures were grown in Millipore-filtered sea water enriched per liter with 0.5 ml of 10 % NaNO3, 0.5 ml of 2 % NaH2PO4 H20, 1 ml of a l-)ug/100 ml solution of Vitamin B12, 1 ml of 4.1 X 10-8 M biotin and 1 ml of Provasoli's PII trace metal mix (Provasoli, 1964). Cultures were maintained at 20 C under a photoregime of 12-12 with irradiation of 1.6 x 103 ergs/cm2/sec from cool white fluorescent tubes. Culture samples were collected by suction filtration and 0.1 g ground in 0.8 ml cold 0.025 Tris-HCl containing 2 mM cysteine-HCl at pH 8.0 in a Ten-Broeck grinder, This homogenate