Taxonomy of the southwestern Atlantic endemic kelp: Laminaria abyssalis and Laminaria brasiliensis (Phaeophyceae,Laminariales) are not different species

Two endemic species of Laminaria, Laminaria abyssalis Joly & Oliveira Filho and L. brasiliensis Joly & Oliveira Filho, from the tropical southwestern Atlantic coast have been described. The aim of this work was to determine the conspecificity of these species based on morphological and molecular analyses (ribulose 1,5‐bisphosphate carboxylase/oxgenase, large subunit (rbcL), internal transcribed spacer (ITS) and cytochrome c oxidase subunit I (coxI)). We found an overlap between the morphological characters that are considered taxonomically important for distinguishing these two species; these characters included a differing pattern of blade splitting. In the three molecular analyses, the Brazilian Laminaria specimens were grouped into one clade with maximum support. These data support the hypothesis that the individuals analyzed represent only one species, L. abyssalis. The molecular analysis also showed L. abyssalis to be sister group to L. digitata.     

Spectral Profiles on the Protease Activities in Laminaria,Undaria and Porphyra

G-PAGE was used to investigate the protease patterns and activities in 11 species of Laminaria Lamx., Undaria Suringar and Porphyra C. Ag. It was shown that (1) the patterns and activities of the protease were pH dependent and the optimum pH for protease activities was 8.0; (2) the more closer the inter-species relationship, the more similarities were observed among the patterns and activities of the proteases; (3) two protease patterns (19 kD, 18 kD) in the eight species of Laminaria were regarded as the genetic indicator of Laminaria; (4) the results suggested that the G-PAGE analysis of proteases could be valuable in the systematic taxonomic study of algae.     

Guluronate content of alginate in Laminaria japonica and Laminaria angustata fronds in laboratory culture

The guluronate (G) content of alginate in the fronds of Laminaria japonica and Laminaria angustata, cultured in the laboratory from zoospore via gametophyte using PESI medium, was determined by the ¹H‐nuclear magnetic resonance spectroscopic method. The G content of alginates in young fronds cultured in various conditions were shown to exceed 55%. These values were remarkably higher than those in field kelp. The G content increased with extending culture period and at low temperature.     

Chlorierte phlorethole aus Laminaria ochroleuca

After acetylation of the phenolic fraction, monochlorodiphlorethol acetate was detected by MS and a monochlorotriphlorethol C heptaacetate was identified in this alga. Halogenation of triphlorethol C acetate did not yield the natural compound, but instead an isomeric monochloro- and a symmetrical dichloroderivative. The high MW phlorotannins are also halogenated.     

Phlorotannins of phaeophycea Laminaria ochroleuca

From the mixture of acetylated phenols of Laminaria ochroleuca several fractions consisting of one or more components were isolated and analysed. Several substances, new or known from other seaweeds were identified: tetraphlorethol-A-nonacetate, fucophlorethol-B-octacetate, fucodiphlorethol-C-decacetate, pentafuhaloltridecacetate, and heptafuhaloloctadecacetate. A structure for an isomer of tetraphlorethol-A-nonacetate named tetraphlorethol-B-nonacetate was suggested. Additional phlorotannins were shown to be present, for which only partial structures could be proven.     

Improved RNA isolation from Laminaria japonica Aresch (Laminariaceae, Phaeophyta)

RNA isolation is difficult in some plants and algae because phenolics, polysaccharides, or other compounds can bind or co-precipitate with RNA, and because the success of RNA isolation can be strain-specific and species-specific. To create an improved RNA isolation protocol for Laminaria japonica Aresch (Laminariaceae, Phaeophyta), four methods for extracting RNA were tested. A cetyltrimethylammonium bromide (CTAB)-based RNA extraction protocol was developed that clearly showed 28S and 18S ribosomal RNA bands and produced RNA with high yield (68 μg g⁻¹ fresh weight) and high quality (A _260/280 ratio 1.96 ± 0.05). The isolated RNA was intact, and RT-PCR analysis confirmed that further molecular application is feasible.     

Chromosome Number of Laminaria digitata Lamour

An investigation of the chromosome number of Laminaria digitataLamour has revealed the diploid complement to be 16. Endomitoticchromosome multiplication has been observed. A similar investigationby Magne has shown the diploid number of chromosomes to be 26in Laminaria flexicaulis Le Jolis and raises the taxonomicalquestion whether these two names can be regarded as synonymsas at present used or covering distant species.     

Effect of the Meristem on Sporification of Laminaria cichorioides

Isolated disks from vegetative thalli of Laminaria cichorioides Miyabe collected in April in Amursky Bay, Sea of Japan, cultivated separately from meristematic sites, developed sporangial sori after 4–6 weeks of cultivation, i.e., 4 months earlier than in natural conditions. The development of reproductive organs in intact plants, on meristematic sites, and also on vegetative disks, cultivated together with meristematic sites, was not observed. The effect of the meristem on L. cichorioides reproduction is supposed to be conditioned by inhibitors of sporification produced by this tissue. We offer a mechanism of sporification regulation for laminarian algae in natural conditions.     

Mariculture of Laminaria japonica (Laminariales, Phaeophyceae) using protoplast regeneration

The conditions for culture of viable protoplasts from Laminaria japonica were investigated and the regenerative processes were observed in detail. As a result of culturing at four water temperatures (5, 10, 15, and 18°C), we found that low water temperature was better for survival, division and rhizoidal formation of protoplast‐derived cells. Only epidermis‐derived protoplasts developed into normal sporophytes through a direct developmental process. Protoplast‐derived cells divided after 5 days and 2–10 celled germlings formed the first rhizoids after 15 days. Only initial sporophytes with the first rhizoids grew to normal sporophytes with multilayered blades, stipes and holdfasts. When these young sporophytes were transplanted into the sea, they grew to normal fertile sporophytes.     

Laminaria digitata: A checkered career

The history of the use of Laminaria digitata is presented. Economically, laminaria has primarily been used as a source of algin. During the 19th century, laminaria were used as an aid in cervical dilatation. Their use persisted in France, Germany, and Japan, but in England, problems of infection associated with laminaria led English physicians to adopt steel dilating instruments. Recently, the liberalization of abortion laws has revived interest in laminaria tents for second trimester aboriton. The primary advantages of laminaria tents for cervical dilatation are that they save time, are efficient, and improve patient comfort.     

Fucans, but not fucomannoglucuronans, determine the biological activities of sulfated polysaccharides from Laminaria saccharina brown seaweed

Sulfated polysaccharides from Laminaria saccharina (new name: Saccharina latissima) brown seaweed show promising activity for the treatment of inflammation, thrombosis, and cancer; yet the molecular mechanisms underlying these properties remain poorly understood. The aim of this work was to characterize, using in vitro and in vivo strategies, the anti-inflammatory, anti-coagulant, anti-angiogenic, and anti-tumor activities of two main sulfated polysaccharide fractions obtained from L. saccharina: a) L.s.-1.0 fraction mainly consisting of O-sulfated mannoglucuronofucans and b) L.s.-1.25 fraction mainly composed of sulfated fucans. Both fractions inhibited leukocyte recruitment in a model of inflammation in rats, although L.s.-1.25 appeared to be more active than L.s.-1.0. Also, these fractions inhibited neutrophil adhesion to platelets under flow. Only fraction L.s.-1.25, but not L.s.-1.0, displayed anticoagulant activity as measured by the activated partial thromboplastin time. Investigation of these fractions in angiogenesis settings revealed that only L.s.-1.25 strongly inhibited fetal bovine serum (FBS) induced in vitro tubulogenesis. This effect correlated with a reduction in plasminogen activator inhibitor-1 (PAI-1) levels in L.s.-1.25-treated endothelial cells. Furthermore, only parent sulfated polysaccharides from L. saccharina (L.s.-P) and its fraction L.s.-1.25 were powerful inhibitors of basic fibroblast growth factor (bFGF) induced pathways. Consistently, the L.s.-1.25 fraction as well as L.s.-P successfully interfered with fibroblast binding to human bFGF. The incorporation of L.s.-P or L.s.-1.25, but not L.s.-1.0 into Matrigel plugs containing melanoma cells induced a significant reduction in hemoglobin content as well in the frequency of tumor-associated blood vessels. Moreover, i.p. administrations of L.s.-1.25, as well as L.s.-P, but not L.s.-1.0, resulted in a significant reduction of tumor growth when inoculated into syngeneic mice. Finally, L.s.-1.25 markedly inhibited breast cancer cell adhesion to human platelet-coated surfaces. Thus, sulfated fucans are mainly responsible for the anti-inflammatory, anticoagulant, antiangiogenic, and antitumor activities of sulfated polysaccharides from L. saccharina brown seaweed.     

Isolation of humic acid from the brown algaeAscophyllum nodosum,Fucus vesiculosus,Laminaria saccharina and the marine angiospermZostera marina

Recent discovery of humic acid (HA) in the free-living, brown algaPilayella littoralis has prompted a search for HA in other live plants. Marine algaeCodium fragile andMonostoma oxyspermum (greens),Chondrus crispus,Palmaria palmata andPolysiphonia lanosa (reds),Ascophyllum nodosum, Fucus vesiculosus andLaminaria saccharina (browns) andZostera marina (marine angiosperm) were investigated for their HA content. Only the brown algae and the marine angiosperm contained HA, which was extracted by a standard procedure augmented with necessary removal of alginic acid (where applicable). The isolated products were identified as HA by comparison of their analytical data, uv-visible, FTIR,¹H NMR spectra and morphologies with those of authentic HA isolated from municipal compost.Authors for correspondence     

Effect of Heavy Metals (Cd, Cu) on the Gametophytes of Laminaria japonica Aresch

Effects of various concentrations of two heavy metals, namely Cd and Cu, on gametophytes of Laminariajaponica Aresch were determined by recording morphological changes of gametophytes, determining pH values and the heavy metal content of the culture solution, calculating the germination rate of sporophytes, and observing heavy metal (Cd) distribution using a fluorescence microscope. The results showed that heavy metals damaged the gametophytes, and were even lethal, and that the higher the concentration of heavy metal ions, the greater the injury to gametophytes. Gametophytes could not survive in culture solutions containing more than 100 mg/L Cd and 50 mg/L Cu and were only able to survive in culture solution containing a mixture of Cd and Cu up to a concentration of 10 mg/L, which indicates that gametophytes have a higher tolerance to Cd than Cu and that multiple heavy metal ions in solution markedly aggravate the damage to gametophytes compared with individual heavy metal ions. With increases in the concentration of the heavy metal, the burgeoning rate of sporophytes decreased acutely, and solutions containing multiple heavy metal ions caused even more marked harm to sporophytes than solutions containing a single heavy metal ion, because most sporophytes died in mixed solutions. The pH value of the culture medium dropped immediately at the beginning (the first day) of treatment, increased over the following days, and then decreased again. The pH of culture media containing multiple heavy metal ions showed greater variation than media containing a single heavy metal ion, with the extent of the decrease in pH of culture media containing multiple ions being greatest during the last period of the experiment. With increases in the concentration of heavy metals, the capacity of gametophytes to accumulate these ions increased. The blue fluorescent light emitted by the Cd- and Cd-binding protein complex existing in gametophytes in media containing different concentrations of Cd showed clearly the distribution of the ion in gametophytes and the results obtained were consistent with distribution determined using other methods.All results of the present study showed that gametophytes of L. japonica play a remarkable role as heavy metal decontaminators, especially with regard to Cd.