Isolation of a cell-fusion hormone from Griffithsia pacifica kylin,a red alga

Filaments of Griffithsia pacifica replace dead cells by the process of cell repair. When an intercalary cell is killed, but its cell wall remains intact holding the two halves of the plant together, the cell above it produces a repair rhizoid cell; the cell below it produces a specialized, rhizoid-like repair shoot cell. The repair rhizoid and shoot grow towards each other, meet, and fuse to form a single shoot cell. Evidence from observations of cell repair in vivo has indicated that the repair rhizoid produces a hormone or hormones which induce the production of the repair shoot, maintain the rhizoid-like morphology and growth of the repair shoot, and attract it to the repair rhizoid for fusion. This hormone has been named rhodomorphin. Using an artificial cell-fusion system we show that repair rhizoids and normal rhizoids, but no shoot cell, can induce decapitated filaments to form repair shoot cells. Decapitated filaments form repair shoot cells only when they are exposed to the hormone within 4–6 h after decapitation; after this time they lose their sensitivity to the hormone. A method has been developed for isolating, and assaying for, the cell-fusion hormone. Rhodomorphin retains its activity for several days at room temperature and for at least two years at-16° C.     

Phototropism in a red alga, Griffithsia pacifica

In the red alga, Griffithsia pacifica, shoot portions of a plantare positively phototropic and rhizoids are negatively phototropic.We have studied the phototropic response of rhizoids which elongateby tip growth. For 45 min after the beginning of unilateralillumination a rhizoid grows straight, then phototropic curvaturebegins and continues rapidly until the rhizoid is growing awayfrom the light. Curvature is 70–80% complete after 3 hr.If the unilateral stimulus is given for a short time (15 min),curvature again begins at 45 min. However, within an additional30–45 min the rhizoid stops growing away from the lightand wanders back towards its original direction of growth. Phototropismis elicited by light of wavelengths from 350 nm to 500 nm; inlight of wavelengths above 550 nm, little, if any, responseoccurs. ¹Present address: Division of Natural Sciences, University ofCalifornia, Santa Cruz, California 95064, U.S.A. (Received December 10, 1976; )     

Laurequinone,a cyclolaurane sesquiterpene from the red alga Laurencia nidifica

From the red alga Laurencia nidifica a new sesquiterpene of cyclolaurane-type was isolated, and the structure elucidated by spectral analyses and chemical means.     

Bromo-compounds of the red alga Lenormandia prolifera

Six bromo-compounds and one bromo-chloro-compound have been detected in Lenormandia prolifera (C.Ag.) J. Agardh (Amansieae; Rhodomelaceae). Hydrolysis of the red pigment floridorubin from the same alga yielded five bromo-, one bromo-chloro and one chloro-phenol. The two main phenols of floridorubin were 2,3-dibromo-4,5-dihydroxy benzyl alcohol (lanosol) and 3,5-dibromo-p-hydroxybenzyl alcohol.     

Laurebiphenyl,a dimeric sesquiterpene of the cyclolaurane-type from the red alga Laurencia nidifica

Laurebiphenyl, a new, dimeric sesquiterpene of the cyclolaurane-type, was isolated from the red alga Laurencia nidifica. Its structure was determined by spectral and chemical means.     

(−)-(S)-4-dimethylsulfonio-2-methoxybutyrate from the red alga Rytiphloea tinctoria

An unusual compound (?)-(S)-4-dimethylsulfonio-2-methoxybutyrate, was identified in aqueous—ethanolic extracts of the red alga Rytiphloea tinctoria.     

Generation of 10,154 expressed sequence tags from a leafy gametophyte of a marine red alga, Porphyra yezoensis.

A total of 10,154 5'-end expressed sequence tags (EST) were established from the normalized and size-selected cDNA libraries of a marine red alga, Porphyra yezoensis. Among the ESTs, 2140 were unique species, and the remaining 8014 were grouped into 1127 species. Database search of the 3267 non-redundant ESTs by BLAST algorithm showed that the sequences of 1080 species (33.1%) have similarity to those of registered genes from various organisms including higher plants, mammals, yeasts, and cyanobacteria, while 2187 (66.9%) are novel. Codon usage analysis in the coding regions of 101 non-redundant EST groups showing significant similarity to known genes indicated the higher GC contents at the third position of codons (79.4%) than the first (62.2%) and the second position (45.0%), suggesting that the genome has been exposed to high GC pressure during evolution. The sequence data of individual ESTs are available at the web site http://www.kazusa.or.jp/en/plant/porphyra/EST/.     

Peroxidase from the red alga Cystoclonium purpureum

A particulate peroxidase has been extracted from the marine red alga Cystoclonium parpureum. Solubilisation was achieved by the use of either digit     

Two new polyhalogenated monoterpenes from the red alga Plocamium cartilagineum

The structures and absolute configurations of two new halogenated alicyclic monoterpenes isolated from the ether extract of the red alga Plocamium cartilagineum (Linn) Dixon were determined as: 1R,2S,4S,5R-5-chloro-2-E-chlorovinyl-1,4-dibromo-1,5-dimethylcyclohexane and 1S,2S,4R,5S-2-bromo-1-E-bromovinyl-4,5-dichloro-1,5-dimethylcyclohexane, respectively.     

Fatty acid composition of the cold-water-inhabiting freshwater red alga Sirodotia Kylin

Four samples of freshwater alga Sirodotia (class Rhodophyceae) collected from two distinct streams in the Mahabaleshwar, Satara district (1,732 m a.s.l.) of the Western Ghats of Maharashtra (India) were analysed for their fatty acid content. The presence of 32 fatty acids was revealed, of which 13 were saturated (SFA), 8 were monounsaturated (MUFA) and 11 were polyunsaturated (PUFA) fatty acids. The major finding was the presence of three pharmaceutically and neutraceutically important PUFAs: arachidonic acid (AA), eicosapentanoeic acid (EPA), and docosahexanoiec acid (DHA). The major fatty acids identified were palmitic (16:0), cis-11,14 icodienoic (20:2), behenic (22:0), cis-8,11,14 eicosatrienoic(20:3n6), cis-4,7,10,13,16,19 docosahexanoeic (22:6n3), cis-13,16 docosadienoic (22:2), erucic (22:1n9), -5,8,11,14,17 eicosapentaenoic (20:5n3), trichosonoic (23:0), nervonic (24:0), arachidonic (20:4n6), cis-10 pentadecanoic (15:1), cis-11,14,17 eicosatrienoic (20:3n3), and myristic acid (14:0). The total PUFA contents ranged from 31.45 to 40.37%. The fatty acids were characterised by the relatively high abundance of PUFAs, while C20 unsaturated acids were appreciably more abundant than C18 unsaturated acids. This is the first report on fatty acid profiles of the genus Sirodotia.     

Chloroplast genome characterization in the red alga Griffithsia pacifica

Summary It has been suggested that cyanobacteria served as the ancestors for rhodophytic algae whose chloroplasts contain chlorophyll a and phycobilins, and that a rhodophyte served as the plastid source for chromophytic plants that contain chlorophylls a and c. Although organellar DNA has been used to assess phylogenetic relatedness among terrestrial plants and green algae whose chloroplasts contain chlorophylls a and b, few data are presently available on the molecular profile of plastid DNA in chromophytes or rhodophytes.In this study the chloroplast genome of the rhodophytic, filamentous alga Griffithsia pacifica has been characterized. DNA was purified from isolated chloroplasts using protease k treatment and sodium dodecyl sulfate lysis followed by density centrifugation in Hoescht-33258 dye-CsCl gradients. Single and double restriction enzyme digests demonstrate that the DNA prepared from purified chloroplasts has a genome size of about 178 kilobase pairs (kb). A restriction map of this chloroplast genome demonstrates that it is circular and, unlike the chloroplast DNA (cpDNA) in most other plants, contains only a single ribosomal DNA operon. DNA was also purified from the mitochondria that co-isolated with chloroplasts. Mitochondrial DNA consists of molecules that range in size from 27 to 350 kb based on restriction endonuclease digestion and electron microscopic analysis.     

Halogenated acetic and acrylic acids from the red alga Asparagopsis taxiformis

Nine halogenated acetic acids and nine halogenated acrylic acids have been identified in the aqueous extract of Hawaiian Asparagopsis taxiformis.     

Bromoperoxidase activity in microplantlet suspension cultures of the macrophytic red alga Ochtodes secundiramea.

Bromoperoxidase is an enzyme found in marine macroalgae that catalyzes the bromination of organic substrates. Photosynthetic microplantlet suspension cultures derived from the macrophytic red alga Ochtodes secundiramea were shown to possess bromoperoxidase. The optimum pH for O. secundiramea bromoperoxidase activity in cell-free extracts was 6.0, and the half-saturation constant for bromination of the exogeneous substrate monochlorodimedone (MCD) was 18 microM. O. secundiramea microplantlets were cultivated in a bubble-column photobioreactor at an incident light intensity of 38 microE x m(-2) x s(-1) (71% of light-saturated photosynthesis, 10:14 light:dark photoperiod), and the kinetics of cell growth and bromoperoxidase production were followed. At these conditions, the specific growth rate was 0.052 x day(-1). The lowest specific bromoperoxidase activity of 0.3 micromol MCD x g(-1) cell x min(-1) occurred during the midexponential phase of growth, and then increased steeply to 1.9 micromol MCD x g(-1) cell x min(-1) during the late stationary phase, suggesting that bromoperoxidase production was part of secondary metabolism. The estimated bromoperoxidase content in the cell mass at late stationary phase was 67 microg x g(-1) dry cell mass, demonstrating that bioreactor production of marine bromoperoxidase is feasible.     

A c-15 non-terpenoid from the red alga Laurencia okamurai

The structure of a new C-15 bromoallene from the red alga Laurencia okamurai was deduced by spectral methods.     

Morphogenesis in the red alga,Griffithsia pacifica: Regeneration from single cells

Summary The regeneration of plants of the red alga Griffithsia pacifica from single, isolated cells is described. Regeneration can start from any cell and is triggered by the removal of an abutting cell. An isolated, single shoot cell forms a shoot and a rhizoidal cell within one day. The shoot then adds new cells by apical division at the rate of 1–2 cells/day; branches are formed at predictable but not fixed locations by budding of subapical cells. Each shoot cell enlarges for 6–8 days. The resulting plant consists of uniseriate, pseudodichotomously-branched shoot filaments with multicellular rhizoidal filaments at their base. The predictability and rapidity of this development combined with the large size of these cells (1.0×0.2 mm) facilitate developmental studies on this organism.     

Terpenoids from marine red alga Laurencia pinnatifida

A new halogenated chamigrene named pinnatifenol, a rearranged chamigrene derivative a diterpenoid have been isolated from the ethyl acetate fraction of marine red alga Laurencia pinnatifida. Their structures were elucidated by spectroscopic means.     

Analysis of expressed sequence tags from the red alga Griffithsia okiensis

Red algae are distributed globally, and the group contains several commercially important species. Griffithsia okiensis is one of the most extensively studied red algal species. In this study, we conducted expressed sequence tag (ESTs) analysis and synonymous codon usage analysis using cultured G. okiensis samples. A total of 1,104 cDNA clones were sequenced using a cDNA library made from samples collected from Dolsan Island, on the southern coast of Korea. The clustering analysis of these sequences allowed for the identification of 1,048 unigene clusters consisting of 36 consensus and 1,012 singleton sequences. BLASTX searches generated 532 significant hits (E-value <10(-4)) and via further Gene Ontology analysis, we constructed a functional classification of 434 unigenes. Our codon usage analysis showed that unigene clusters with more than three ESTs had higher GC contents (76.5%) at the third position of the codons than the singletons. Also, the majority of the optimal codons of G. okiensis and Chondrus crispus belonging to Bangiophycidae were C-ending, whereas those of Porphyra yezoensis belonging to Florideophycidae were G-ending. An orthologous gene search for the P. yezoensis EST database resulted in the identification of 39 unigenes commonly expressed in two rhodophytes, which have putative functions for structural proteins, protein degradation, signal transduction, stress response, and physiological processes. Although experiments have been conducted on a limited scale, this study provides a material basis for the development of microarrays useful for gene expression studies, as well as useful information for the comparative genomic analysis of red algae.