Brown Alga Laminaria Saccharina Research Articles

The effects of the excretory-secretory products of fouling organisms on settlement of larvae of the sponge Halichondria panicea (Pallas, 1766) (Porifera: Demospongiae)

The effects of the excretory-secretory products (ESPs) of several fouling organisms on the larvae of the sponge Halichondria panicea were assessed in laboratory experiments. The ESPs of the brown alga Laminaria saccharina significantly stimulated larval settlement and metamorphosis, while the metabolites excreted by conspecific adult colonies were harmful to H. panicea larvae. The ESPs of the ascidians Styela rustica and Molgula citrina and the blue mussel Mytilus edulis impeded both the settlement and metamorphosis of the sponge larvae to varying degrees. The chemical cues of the bivalve Hiatella arctica had no significant effect on the number of settled larvae of H. panicea but retarded their metamorphosis.

Biocatalytic formation of synthetic melanin: The role of vanadium haloperoxidases, L-DOPA and iodide

The vanadium haloperoxidase (V-HPO) enzyme, extracted from the brown alga Laminaria saccharina, is able to catalyze the formation of a black precipitate, using as precursor the amino acid l-dopa in the presence of hydrogen peroxide and iodide, in one-pot synthesis. The l-dopa oxidation is a multistep reaction with a crucial role played by the iodide in the enzyme catalyzed peroxidative production of dopachrome, a well known intermediate in the synthesis of melanin. Dopachrome is then converted to a synthetic form of melanin through a polymerization reaction. Factors, such as buffer composition and pH, influence significantly the reaction first steps, but further steps of melanin production are hardly influenced. The biosynthetic melanin produced through the combination V-HPO/I/H 2O 2, was characterized by several spectroscopic techniques (UV–vis and FT-IR) as well as XRD. Moreover, this biopolymer is light sensitive, decomposing into oligo- and monomeric units. Scanning electron microscopy (SEM) imaging showed different morphologies when compared with commercial available melanin. The biosynthetic production of melanin can have a wide range of applications from photosensitive cells to biomedicine with the advantage of being produced under eco-friendly and mild conditions.

The Path of Carbon in Photosynthesis. XXV. Plant and Algal Growth Responses to Glycopyranosides

ABSTRACT Substituted glycopyranosides were applied to various plant species as foliar and root treatments, with and without nutrient supplements, and growth was compared to untreated or nutrient controls. When formulated with specific fertilizers, particularly available nitrogen, methyl and ethyl glycopyranosides significantly enhanced the overall growth of vascular plants compared to controls provided with the same nutrients. In contrast, vascular plants treated with alkylglycopyranosides without nutrients showed growth equivalent to that of untreated controls. Nitrogen-supplemented alkylglycopyranosides provided as foliar applications of 100 mM, or as root treatments between 35 and 50 mM, consistently enhanced root and shoot productivity. In addition to the vascular plant species tested, the brown alga Laminaria saccharina exhibited significant growth enhancement over nutrient controls when treated with alkylglycopyranosides supplemented with nutrients, especially under low irradiance. Overall, these results indicate that growth of photosynthetic organisms is enhanced by exogenous alkylglycopyranosides supplemented with nitrogen and micronutrients, but not by alkylglycopyranosides alone.

137Cs content and concentration factors in benthic organisms in the dump sites for solid radioactive waste in the Kara Sea

Radioactive contamination was studied in macrobenthic invertebrates and algae of the Abrosimov, Stepovoy and Tsivolky Bays of the Novaya Zemlya Archipelago and the adjacent regions of the Kara Sea during the cruises 73d and 81st on board R/V Professor Shtokman in the years 2005-2006. Maximum concentration 137 Cs in sediment in studied area has been detected in the layer 10-12cm in the Abrosimov Bay (150Bq/kg) and in the layer 4-6cm in the Stepovoy Bay (100Bq/kg). Concentration of 137 Cs in benthos was up to 3.19Bq/kg of wet weight. The highest concentration has been found in benthos of the Abrosimov and Stepovoy Bays: the holothurian Myriotrochus rinkii, the isopod Saduria sabini, ophiuroids Ophiocten sericeum and Stegophiura nodosa. Myriotrochus rinkii, Saduria sabini and the brown alga Laminaria saccharina were characterized by the highest 137 Cs concentration factor - 994, 599 and 425 respectively. Caesium-137 contamination occurs locally in the studied area closed to the radioactive waste disposal and does not affect on qualitative structure of the macrobenthic communities.

Diversity of antibiotic-active bacteria associated with the brown alga Laminaria saccharina from the Baltic Sea.

Bacteria associated with the marine macroalga Laminaria saccharina, collected from the Kiel Fjord (Baltic Sea, Germany), were isolated and tested for antimicrobial activity. From a total of 210 isolates, 103 strains inhibited the growth of at least one microorganism from the test panel including Gram-negative and Gram-positive bacteria as well as a yeast. Most common profiles were the inhibition of Bacillus subtilis only (30%), B. subtilis and Staphylococcus lentus (25%), and B. subtilis, S. lentus, and Candida albicans (11%). In summary, the antibiotic-active isolates covered 15 different activity patterns suggesting various modes of action. On the basis of 16S rRNA gene sequence similarities >99%, 45 phylotypes were defined, which were classified into 21 genera belonging to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. Phylogenetic analysis of 16S rRNA gene sequences revealed that four isolates possibly represent novel species or even genera. In conclusion, L. saccharina represents a promising source for the isolation of new bacterial taxa and antimicrobially active bacteria.

Phylogenetic analysis of bacteria associated with Laminaria saccharina.

Bacterial communities associated with the brown alga Laminaria saccharina from the Baltic Sea and from the North Sea were investigated using denaturing gradient gel electrophoresis and 16S rRNA gene clone libraries. The rhizoid, cauloid, meristem and phyloid revealed different 16S rRNA gene denaturing gradient gel electrophoresis banding patterns indicating a specific association of bacterial communities with different parts of the alga. Associations with cauloid and meristem were more specific, while less specific associations were obtained from the old phyloid. In addition, seasonal and geographical differences in the associated communities were observed. Results from 16S rRNA gene libraries supported these findings. Bacterial phylotypes associated with the alga were affiliated with the Alphaproteobacteria (nine phylotypes), Gammaproteobacteria (nine phylotypes) and the Bacteroidetes group (four phylotypes). A number of bacteria associated with other algae and other marine macroorganisms were among the closest relatives of phylotypes associated with L. saccharina.

Effect of variation in the protein value of the red macroalga Palmaria palmata on the feeding, growth and gonad composition of the sea urchins Psammechinus miliaris and Paracentrotus lividus (Echinodermata)

The sea urchins Psammechinus miliaris and Paracentrotus lividus were fed three macroalgal diets with varying protein content over a 90-day period. These diets were the red alga Palmaria palmata, which had been grown in seawater enriched with two levels of ammonia-N and contained a protein content of either 41% (High-N) or 32% (Low-N) and the brown alga Laminaria saccharina (23% protein). A significantly different response to the macroalgal diets by the two sea urchin species was found in terms of food consumption rate, food conversion efficiency, gonadal growth and gonad nutritional composition. P. miliaris was able to efficiently utilise the High-N P. palmata, whereas P. lividus exhibited a higher food conversion efficiency (FCE) and specific growth rate (SGR) when fed the Low-N compared with the High-N P. palmata. P. miliaris had a significantly higher food consumption rate and higher gonad index (GI) compared with P. lividus, irrespective of diet type. The lowest FCE, SGR and GI were shown by both species fed L. saccharina. No interspecific difference in gonadal nitrogen content was observed, although a positive relationship was shown between dietary and gonadal nitrogen content for both species. All three macroalgal diets produced bright orange or yellow orange gonad colour in P. lividus. High-N and Low-N P. palmata improved gonad colouration in P. miliaris compared with L. saccharina. The results suggest that P. miliaris can efficiently assimilate high protein plant-based diet, whereas P. lividus is less capable of benefiting from high dietary protein levels and this should be taken into consideration when culturing this species either in land-based or sea-based polyculture systems.

Breaking seasonal limitation: year-round sporogenesis in the brown alga Laminaria saccharina by blocking the transport of putative sporulation inhibitors

Year-round induction of sporogenesis of Laminaria saccharina was performed by mechanically blocking the transport of the putative sporulation inhibitors produced by the blade meristem and culturing the plants in constant short days. Sporogenesis was successfully induced by removal of the blade meristem, either by cultivating distal blade fragments or by performing a transverse cut in the frond. The earliest sorus formation after artificial induction was 10 days. The age of the sporophytes used for induction was 6–11 months or 2 years in tank-grown or field-collected sporophytes, respectively. Zoospores were successfully released in all cases. Thus, by year-round artificial induction of sporogenesis, (1) sporeling production of L. saccharina and thereafter sporophyte cultivation could be achieved without seasonal limitation, and (2) the life cycle of L. saccharina (from spore to spore) could be completed within 8 months under controlled conditions.

Biomass, photosynthesis and growth of Laminaria saccharina in a high-arctic fjord, NE Greenland

Biomass, photosynthesis and growth of the large, perennial brown alga Laminaria saccharina (L.) Lamour. were examined along a depth gradient in a high-arctic fjord, Young Sound, NE Greenland (74°18′N; 20°14′W), in order to evaluate how well the species is adapted to the extreme climatic conditions. The area is covered by up to 1.6-m-thick ice during 10 months of the year, and bottom water temperature is 4 m long and older than 4 years. In contrast to temperate stands of L. saccharina, old leaf blades (2–3 years old) remained attached to the new blades. The old tissues maintained their photosynthetic capacity thereby contributing importantly to algal carbon balance. The photosynthetic characteristics of new tissues reflected a high capacity for adaptation to different light regimes. At low light under ice, or in deep water, the chlorophyll a content and photosynthetic efficiency (α) were high, while light compensation (E c) and saturation (E k) points were low. An E c of 2.0 µmol photons m–2 s–1 under ice allowed photosynthesis to almost balance, and sometimes exceed, respiratory costs during the period with thick ice cover but high surface irradiance, from April through July. Rates of respiration were lower than usually found for macroalgae. Annual elongation rates of leaf blades (70–90 cm) were only slightly lower than for temperate L. saccharina, but specific growth rates (0.48–0.58 year–1) were substantially lower, because the old blades remained attached. L. saccharina comprised between 5% and 10% of total macroalgal biomass in the area, and the annual contribution to primary production was only between 0.1 and 1.6 g C m–2 year–1.

The light-harvesting antenna of brown algae: highly homologous proteins encoded by a multigene family.

Accessory light-harvesting complexes (LHCFs) were isolated from the brown alga Laminaria saccharina. Complexes specifically associated with photosystem I or II are identical with each other with respect to molecular mass, isoelectric point and behavior on anion-exchange chromatography or non-denaturing isoelectric focusing. The purified complexes also have similar pigment composition and spectroscopic properties. It is concluded that LHC antennae associated with photosystem I or II cannot be distinguished biochemically. After screening of genomic and cDNA libraries produced from L. saccharina sporophytes, six lhcf genes were isolated. Sequence analysis of these lhcf genes showed a high level of homology between the encoded polypeptides. Comparisons with coding sequences of lhcf genes from Macrocystis pyrifera and expressed sequence tags from Laminaria digitata (two other Laminariales) indicated that these proteins are probably very similar in all brown algae. Another feature common to the lhcf genes characterized was the presence of an intron in the coding region corresponding to the plastid-targeting presequence. The sequence similarity extended to the 5' and 3' UTRs of several genes. In spite of the common origin of the chloroplasts, no light-regulating elements involved in the expression of the genes encoding the higher-plant light-harvesting proteins has been found in the UTRs.

Resonance Raman spectroscopy of a light-harvesting protein from the brown alga Laminaria saccharina.

Resonance Raman spectroscopy of an antenna protein from the brown alga Laminaria saccharina has been used to investigate the molecular structure of this light-harvesting complex (LHC) at the level of its bound pigments, chlorophylls (chl) a and c and the xanthophyll fucoxanthin. Evidence has been obtained for the conservation of pigment structure during the isolation procedure used. Six chl a and two chl c molecules are indicated from the positions and relative contributions of stretching modes of their keto-carbonyl groups. Of special interest is the presence of a population of chls a having a protein-binding conformation highly similar to that seen in antenna proteins from higher plants, possibly indicating a common structural motif within this extended gene family. The eight fucoxanthin molecules evidenced are all in the all-trans conformation; however, one or two have a highly twisted configuration. The results are discussed in terms of common and varying structural features of LHCs in higher plants and algae.

Dynamics and seasonal growth strategies of the brown alga Laminaria saccharina in the Barents Sea

Dynamics and seasonal growth strategies of the brown alga Laminaria saccharina in the Barents Sea

The role of larval settling behaviour in determination of the specific habitat of the hydrozoan Dynamena pumila (L.) larval settlement in Dynamena pumila (L.)

Dynamena pumila (L.) lives on the brown alga Laminaria saccharina and Fucus serratus, in areas exposed to waves and currents. An experimental study of settling behaviour and metamorphosis of the planulae was conducted. Reconstruction of larval settlement showed that the colonies of D. pumila developed and fed in high flow environments, due not only to various adaptations of their morphology, but in great extent, due to the specific behaviour of larvae at, and prior to settlement and metamorphosis. Positive phototaxis by newly liberated planulae of D. pumila leads to colonization of illuminated zones on fucoid thalli and laminarian stipes and blades, where they metamorphosed in response to microbial films covering the algal surface. Crawling planulae of D. pumila were far more resistant to rapid water flows than the planulae of other hydroids, what allows this hydroid to establish its colonies in places with strong water movements, where the other species could not develop. Temporary exposure to air facilitated attachment and metamorphosis of the planulae, which probably settle and undergo metamorphosis during the periods of low-tidal emersion.

Photolithotrophic cultivation of Laminaria saccharina gametophyte cells in a bubble-column bioreactor

The photolithotrophic cultivation of a novel cell suspension culture derived from the microscopic, filamentous gametophyte life phase of the complex brown alga Laminaria saccharina was feasible in an illuminated bubble-column bioreactor at 13°C using CO 2 in air as the sole carbon source for growth. Maximum cell densities exceeding 1,000 mg dry cell weight (dcw) l −1 and specific growth rates of 0.15 day −1 were attained within a 20-day cultivation period. Initial cell density had a significant effect on the final biomass density of the clumped cell suspension, but no significant effect on the specific growth rate. Although the optimum aeration rate for culture growth was 1.0 l air min −1 l −1 culture (vvm), the culture was not CO 2-transport limited at 0.17–2.0 vvm. Initial nitrate concentrations at or above 63.5 mg NaNO 3 l −1 in the GP2 artificial seawater medium had no significant effect on the specific growth rate or final biomass density. Both specific growth rate and final biomass density data were correlated to incident light intensity over the range of 1–91.2 μE m −2 s −1 using an exponential model for light-saturated growth where light-saturated growth was achieved within a low-incident light intensity of 20 μE m −2 s −1.

Dietary accumulation of UV-absorbing mycosporine-like amino acids (MAAs) by the green sea urchin (Strongylocentrotus droebachiensis)

The bioaccumulation of ultraviolet radiation-absorbing mycosporine-like amino acids (MAAs) by Strongylocentrotus droebachiensis (Muller) was determined in specimens maintained on MAA-rich and MAA-deficient diets. Individuals were fed either the red alga Mastocarpus stellatus (Stackhouse), which has a high concentration of the MAA shinorine (6.98 nmolmg−1 dry wt), and trace amounts of the MAAs porphyra-334, asterina-330 and palythine, or the brown alga Laminaria saccharina (Lamouroux), which contains no detectable MAAs. Reproductively spent urchins were fed ad libitum during a 9 mo period in 1992 to 1993 until they were once again gravid. To monitor accumulation, samples of urchin tissues and ingested food were taken throughout the 9 mo period from males and females maintained on each diet, and the concentrations of MAAs determined using high performance liquid chromatography. Urchins maintained on a diet of M. stellatus showed an ovarian shinorine concentration (8.33 nmol mg−1 dry wt) 25 times higher than those fed L. saccharina. There was no change in MAA content of testes or somatic tissues in either feeding group. More than 99% of the MAAs present in an experimental meal of M. stellatus were removed during passage through the gut. Previous studies have inferred dietary accumulation of MAAs by comparing MAAs present in animal tissues with the consumer's potential diet in the field. This is the first study to have monitored MAA accumulation in animal tissues in conjunction with a controlled diet having a known MAA composition. Concentrating MAAs in the ovaries may provide eggs released into the water column with protection from damaging solar ultraviolet radiation.

Bioreactor seaweed cell culture for production of bioactive oxylipins

Liquid cell suspension cultures derived from marine plants have the potential to biosynthesize novel biomedicinal compounds in a controlled environment. Of particular interest are the eicosanoids and related oxylipins emanating from the 15-lipoxygenase manifold of the arachidonic acid cascade, which is active in the brown algaLaminaria saccharina. Filamentous cell clumps ofL. saccharina isolated from female gametophytes were cultured in an illuminated bubble-column bioreactor in GP2 artificial seawater nutrient medium at 13 °C and air flow rate of 0.35 L air min−1 L−1 culture (vvm). Growth kinetics and biomass productivity data were obtained as a function of incident light intensity (2.4 to 98μmol photon m−2 s−1) and initial cell density (27 to 149 mg DCW L−1). Maximum cell densities exceeded 1200 mg DCW L−1 after a 20 day cultivation time at optimal conditions of 98μmol photon m−2 s−1 and 118 mg DCW L−1 initial cell density. Qualitative analysis of chloroform/methanol extracts of the cell culture biomass by GC-MS confirmed the presence of the hydroxy fatty acids 13-HODTA and 13-HOTE, the likely products of 15-lipoxygenase catalyzed oxidation of linoleic or linolenic acids.

Fucoxanthin-chlorophyll a/c light-harvesting complexes of Laminaria saccharina: partial amino acid sequences and arrangement in thylakoid membranes.

The N-terminus of the major polypeptide component of the light-harvesting complex (LHC) from the brown alga Laminaria saccharina is blocked. Two partial sequences, one near the N-terminus and the other near the C-terminus, have been obtained by chemical cleavage with acetic acid and N-chlorosuccinimide. Four peptides were separated after trypsin digestion of the thylakoid membranes. One fragment is not phosphorylated, is not blocked, and has been sequenced. Purification on a reversed-phase column showed two forms of the LHC protein: the more hydrophobic form appears to be bound to photosystem I. These results are compared with LHC from other Chromophytes and the CAB family of green plants.

Carbohydrate degradation and methane production during fermentation ofLaminaria saccharina (Laminariales, Phaeophyceae)

Anaerobic digestion of the brown algaLaminaria saccharina (L.) Lamour. harvested in spring and autumn was carried out at controlled laboratory conditions in stirred fermentor systems. Due to the normal seasonal variations, the autumn material had a much higher content of carbohydrates such as mannitol and laminaran. Both batch and semi-continuous feeding conditions were investigated for periods up to 800 h, with inoculum provided from previous kelp fermentations. In batch cultures, the methane yield from the autumn material was doubled compared to that of the spring material. Semi-continuous conditions gave more similar methane yields for both raw materials, 0.22 and 0.27 l CH4 per g VS for spring and autumn material, respectively. In all experiments, mannitol and laminaran were reduced to less than 5‰ of the initial values within 24–48 hours after inoculation, whereas 30‰ of the alginate content was detectable even after 30 days. Viscometry revealed that this material was severely depolymerized, and alginate lyase activity was found to develop rapidly in all cultures. Although mannitol and laminaran were fermented much faster than alginate, the total accumulated methane yields seemed to be determined by the total carbohydrate content of the raw material during extended semi-continuous feeding.

Temperature acclimation of respiration and photosynthesis in the brown algaLaminaria saccharina

Sporophytes of the brown algaLaminaria saccharina (L.) Lamour grown at 15°C contained significantly more chlorophylla (chla) than did similar plants grown at 5°C. The increase in chla in 15°C plants was due to increased numbers of photosystem II reaction centes, and possibly to increased photosynthetic unit size, compared with 5°C plants. These changes were associated with increasedα values (photosynthetic efficiencies) in 15°C-grownL. saccharina relative to 5°C-grown plants. The changes inα together with reduced respiration rates allowed 15°C-grownL. saccharina to achieve net photosynthesis and light-saturated photosynthesis at a lower photon fluence rate (PFR) than 5°C plants when both groups were assayed at the same temperature (15°C). The photon fluence rates necessary to reach the compensation point and achieve light-saturated photosynthesis (I c andI k , respectively) increased with increasing incubation temperature inL. saccharina grown at both 5 and 15°C. However, acclimation responses to growth temperature compensated for the short-term effect of temperature onI c andI k . Consequently, plants grown at 5 and 15°C were able to achieve similar rates of light-limited photosynthesis, and similarI c andI k values at their respective growth temperatures. These responses are undoubtedly important for perennial seaweeds such asL. saccharina, which frequently grow in light-limited habitats and experience pronounced seasonal changes in water temperature.

Laboratory culture of gametophytic stages of the marine macroalgae champia parvula (rhodophyta) and laminaria saccharina (phaeophyta)

AbstractMethods to help characterize the toxicity of effluent discharges within the National Pollutant Discharge Elimination System have been developed for the marine red alga Champia parvula and are currently being developed for the brown alga Laminaria saccharina. These methods require maintaining male and female gametophytes in laboratory cultures. Aseptic techniques are recommended even though the cultures are not intended to be axenic; the purpose is to guard against microalgal contamination. C. parvula can be grown at room temperature, but L. saccharina requires a controlled temperature chamber (12–15°C). Both species can be cultured successfully in either natural or artificial seawater.