Bromophenols from red algae.

3,5-Dibromo-p-hydroxybenzyl alcohol is reported as a natural constituent of Odonthalia dentata and Rhodomela confervoides. The amounts isolated, based on the fresh weight of the tissue, were 0.024 and 0.003 percent, respectively. A major phenolic compound in both algae was 2,3-dibromo-4,5-dihydroxybenzyl alcohol.

Sulfohydrolase Activity and Carrageenan Biosynthesis in Chondrus crispus (Rhodophyceae).

An enzyme catalyzing the conversion of mu- to kappa-carrageenan has been demonstrated in both haploid and diploid plants of Chondrus crispus. It acts at the polymer level producing 3,6-anhydro-d-galactose with the stoichiometric release of sulfate. Two-thirds of the recoverable enzyme was associated with the 15,000g pellet most of which could be solubilized by passage through a Ribi Cell Fractionator. The enzyme precipitated between 2.65 and 4.24 m (NH(4))(2)SO(4) and was partly purified on DEAE-cellulose columns. This sulfohydrolase has a pH optimum near 6.5 and is inhibited by molybdate, phosphate, sulfate, tungstate, cysteine, ATP, GTP, UDP, and by lambda-carrageenan. No activator was found. The enzyme showed a similar affinity for several preparations of mu-carrageenan and for the kappa-carrageenase-resistant fraction from kappa-carrageenan thus confirming that the latter is a biosynthetically unfinished molecule.A comparable extract from Gigartina stellata gave a higher specific activity for the sulfohydrolase, but was otherwise quite similar to the Chondrus enzyme.

Physodes and the phenolic compounds of brown algae. Isolation and characterization of phloroglucinol polymers from Fucus vesiculosus (L.)

A series of vanillin-reactive compounds has been isolated from extracts of the brown alga Fucus vesiculosus. The first three members of this series have been examined by mass spectrometry, nuclear magnetic resonance spectrometry, and chemical methods, and were shown to be phloroglucinol, its phenyl-linked dimer, and a timer also composed of phloroglucinol units. Evidence is presented for the presence of tetrameric, pentameric, and hexameric phloroglucinol derivatives. Polymeric vanillin-reactive compounds were isolated and separated into two fractions. Oxidative hydrolysis of the major one produced phloroglucinol and related oligomers in low yields. The classical vanillin reactivity of physodes may thus be attributed to phloroglucinol-containing derivatives, as originally proposed by Crato (Crato, E.: Ber. Dtsch. Bot, Ges. 10, 295-302 (1892)).

The occurrence and seasonal variation of gigartinine and L-citrullinyl-L-arginine in Chondrus crispus Stackh.

Gigartinine, 5-(3-amidinoureido)-2-aminovaleric acid, and L-citrullinyl-L-arginine were islated from aqueous extracts of Chondrus crispus (Rhodophyceae). Their identifications were confirmed by chemical procedures, and 1H and 13C nuclear magnetic resonance and infrared spectroscopic methods. Citrullinylarginine, gigartinine, taurine, citrulline, and glutamic acid were the predominant free amino compounds. Citrullinylarginine showed the most pronounced change in concentration. This occurred during the winter months when it reached a maximum (in March) of 58 mumol/g fresh weight, a value 10 times greater than that of any of the free amino acids and equal to 50% of the total organic nitrogen in the plant; All of these compounds were depleted to a minimum of about 1 mumol/g fresh weight in October. Both gigartinine and citrullinylarginine were detected in Ahnfeltia plicata, Gracilaria sp. Petrocelis middendorfii, Polyides rotundus, Polysiphonia lanosa, and Rhodomela confervoides.

Evaluation of evidence for the presence of indole-3-acetic acid in marine algae.

Using a two-dimensional thin layer chromatography system (TLC) we have been unable to detect endogenous indole-3-acetic acid (IAA) (as an Ehrlichpositive spot on TLC plates) in the acidic, ether-soluble fraction of alkaline hydrolysates of 10 species of marine algae. Exogenously added IAA, admixed with algal extracts, was completely separated on chromatograms from other Ehrlich-positive compounds which were present in the extracts. Several regions of auxin-like activity were located on chromatograms of Fucus extracts. From experiments on the recovery of exogenously added IAA from algal extracts, we calculate that if IAA is present in algae, the levels are below 0.1 µg IAA/g fresh weight. The claim by previous workers that IAA is present in marine algae is critically discussed.

STUDIES ON THE ALGAL CUTICLE(1).

A chemically resistant cuticle fraction was isolated from 5 phaeophycean, 1 rhodophycean, and 11 chlorophycean marine algae using acid treatment alone, or acid treatment followed by leaching in cupra-ammonium. In Cladophora rupestris and Chaetomorpha melagonium this fraction consists of several alternate microfibrillar and amorphous layers similar in appearance to those seen in innermost carbohydrate-rich regions and amount to about 1/10 or more of the cell wall thickness. In Porphyra umbilicalis and Padina vickersiae it is a single layer less than I µ thick, accounting for 1/50-1/100 of the cell wall in Porphyra, and 1/5-1/10 of the cell wall in Padina. The cuticle fractions of all 4 algae contain surprisingly large amounts of protein (about 70% in Cladophora and 80% in Porphyra). Similarities in the behavior of cuticles obtained from the other 12 species studied suggest that they may have a similar protein-rich composition.

ANTIALGAL ACTIVITY OF SOME SIMPLE PHENOLS(1).

The antialgal activity of a number of simple phenols was examined for their effect on the growth of 7 species of unicellular marine algae. The 3 knoiun algal phenols, 5-bromo-3,4-dihydroxybenzaldehyde; 2,3-dibromo-4,5-dihydroxybenzylalcohol, and 3,4-dihy-droxyphenylethylamine, were highly toxic as were other ortho dihydroxy compounds. Monohydroxy compounds were notably less toxic. Skeletonema costatum and Olisthodiscus sp. were the most sensitive organisms examined and Dunaliella tertiolecta was the most resistant. Possible ecological implications of these results are discussed.

Carrageenans in the gametophytic and sporophytic stages of Chondrus crispus.

The morphologically similar sporophytic and gametophytic plants of Chondrus crispus Stackhouse were examined and it was shown that the former contain λ-carrageenan. The gametophytes contain Ï°- and two additional carrageenans which are KCl-soluble and may comprise up to 25% of the total carrageenan. After alkaline modification, these KCl-soluble components were separated into a gel and a soluble carrageenan. The gel was indistinguishable from Ï°-carrageenan and presumably was derived from µ-carrageenan while the KCl-soluble fraction possessed a unique infrared spectrum easily distinguished from alkali-modified λ-carrageenan. This appears to represent a third carrageenan in the gametophytes.Our observations suggest that the biologically separate plants of C. crispus exhibit distinctive patterns of sulfation of their galactans. The sporophytes add SO4 (2-) at C2 of the precursor, whereas the gametophytes appear to add it principally at the available C4 positions. Both types of plant are capable of sulfating at C6 of the 4-linked galactose unit.

ALARM GRANDIFOLIA J. AGARDH FROM NOVA SCOTIA(1).

Alaria grandifolia is recorded from Nova Scotia for the first time and is briefly compared with A. esculenta from this area.