Epiphytic Red Algae Research Articles

Rheology and characterization of sulfated agarans from the edible epiphytic red alga, Vertebrata lanosa (truffle seaweed)

The effect of different cations (K+, Ca2+ and Ba2+) on the gel forming properties of sulfated polysaccharides isolated from the red epiphytic alga, Vertebrata lanosa, using a successive cold (25 °C) and hot (95 °C) alkaline extraction process is presented. The elucidation of their monomeric composition using a two-step reductive hydrolysis and structural analyses (1D and 2D NMR) revealed d-galactose (G) linked to 3,6-anhydro-l-galactose (LA) and also sulfated 3,6-anhydro-l-galactose (L6S) as the major monomers with some amounts of glucose, β-d-xylose, 6-O-methyl-d-galactose (G6M), 2-O-methyl-l-anhydrogalactose (LA2M) and l-arabinofuranose. This composition implied the presence of both diads of agaran types, funoran and porphyran in polysaccharides from Vertebrata lanosa. Similar to funorans, their gelation, was highly influenced in the presence of Ba2+ ions compared to other tested salts. 0.2 M of BaCl2 in the hot extracted fractions recorded storage modulus (Gʹ) to up to ∼80 Pa and increased complex viscosity to 16,000 mPa s compared to the <5 Pa storage modulus from pristine solutions with no added salts. Sulfate amount contained within these fractions ranged up to ∼30% with less than 1 % (gallic acid equivalent, GAE) total phenolic compounds. Some of these fraction, nonetheless, have shown good α-amylase and reactive oxygen species (ROS) inhibition activities thus suggesting a nutraceutical potential of hydrocolloids from this algal species.

Residency, home range and tidal habitat use of Green Turtles (Chelonia mydas) in Port Curtis, Australia

To understand habitat requirements of green turtles in an important foraging area subject to both anthropogenic and natural perturbations, we examined residency, home range and habitat use of juvenile, sub-adult and adult green turtles (Chelonia mydas) in Port Curtis, Australia, using passive acoustic telemetry. Acoustic tags were attached to turtles at Pelican Banks (n = 33) and Wiggins Island (n = 16). Between May 2013 and September 2014, tagged turtles were detected > 1.3 million times by 46 acoustic receivers. Data demonstrated variability in residence index and home range size between Pelican Banks and Wiggins Island that was largely attributed to larger body size at Pelican Banks and habitat differences. Tide had a significant influence of movement and habitat use. At Pelican Banks turtles moved into intertidal seagrass beds at high tide and retreated to the channel at low tide. At Wiggins Island, high tide 50% KUD area was more than double low tide area and turtles moved into the mangroves at high tide and retreated to channels at low tide. Diet reflected availability of food resources; seagrass dominated diet at Pelican Banks whereas epiphytic red algae dominated diet at Wiggins Island. There was no evidence of a diurnal shift in home range or habitat use. The use of intertidal areas by both turtles and small recreational craft during high tide at Pelican Banks resulted in increased risk of vessel strike. Unusually short residency at Pelican Banks suggested that animals had either relocated to another foraging area or a combination of recent flooding, port development and reduced seagrass coverage during the period of monitoring resulted in higher emigration rates than previously demonstrated for this species. Acoustic telemetry is a valuable tool for obtaining fine-scale, long- term data on movement and residency of green turtles.

Development and Validation of an HPLC Method for the Quantitative Analysis of Bromophenolic Compounds in the Red Alga Vertebrata lanosa.

Bromophenols are a class of compounds occurring in red algae that are thought to play a role in chemical protection; however, their exact function is still not fully known. In order to investigate their occurrence, pure standards of seven bromophenols were isolated from a methanolic extract of the epiphytic red alga Vertebrata lanosa collected in Brittany, France. The structures of all compounds were determined by NMR and MS. Among the isolated substances, one new natural product, namely, 2-amino-5-(3-(2,3-dibromo-4,5-dihydroxybenzyl)ureido)pentanoic acid was identified. An HPLC method for the separation of all isolated substances was developed using a Phenomenex C8(2) Luna column and a mobile phase comprising 0.05% trifluoroacetic acid in water and acetonitrile. Method validation showed that the applied procedure is selective, linear (R2 ≥ 0.999), precise (intra-day ≤ 6.28%, inter-day ≤ 5.21%), and accurate (with maximum displacement values of 4.93% for the high spikes, 4.80% for the medium spikes, and 4.30% for the low spikes). For all standards limits of detection (LOD) were lower than 0.04 μg/mL and limits of quantification (LOQ) lower than 0.12 μg/mL. Subsequently, the method was applied to determine the bromophenol content in Vertebrata lanosa samples from varying sampling sites and collection years showing values between 0.678 and 0.005 mg/g dry weight for different bromophenols with significant variations between the sampling years. Bioactivity of seven isolated bromophenols was tested in agar diffusion tests against Staphylococcus aureus and Escherichia coli bacteria. Three compounds showed a small zone of inhibition against both test organisms at a concentration of 100 µg/mL.

Screening for osteogenic activity in extracts from Irish marine organisms: The potential of Ceramium pallidum.

Extracts and compounds derived from marine organisms have reportedly shown some osteogenic potential. As such, these bioactives may aid in the treatment of musculoskeletal conditions such as osteoporosis; helping to address inefficacies with current treatment options. In this study, 72 fractions were tested for their in vitro osteogenic activity using a human foetal osteoblast (hFOB) cell line and bone marrow derived mesenchymal stem cells (MSCs), focusing on their cytotoxic, proliferative and differentiation effects. Extracts dissolved in dimethyl sulfoxide and ethanol showed no significant osteogenic potential. However, two extracts derived from powder residues (left over from original organic extractions) caused a significant promotion of MSC differentiation. Bioactivity from powder residues derived from the epiphytic red algae Ceramium pallidum is described in detail to highlight its treatment potential. In vitro, C. pallidum was shown to promote MSC differentiation and extracellular matrix mineralisation. In vivo, this extract caused a significant increase in opercular bone growth of zebrafish larvae and a significant increase in bone density of regenerated adult caudal fins. Our findings therefore show the importance of continued screening efforts, particularly of novel extract sources, and the presence of bioactive compounds in C. pallidum extract.

Defense mechanisms of sargassacean species against the epiphytic red alga Neosiphonia harveyi.

Flora diversity and abundance of epiphytes are specific to their basiphyte species and may relate to variations in the defensive abilities of basiphytes. Thus, investigating the interactions between epiphytes and basiphytes is useful for a better understanding of the biological impact of epiphytism and the survival strategies of basiphytes. We examined the epiphyte density on five sargassacean species at six locations between two study sites, which showed that the epiphytic red alga Neosiphonia harveyi was remarkably less abundant on Sargassum siliquastrum at all locations. To assess its defense mechanism against N.harveyi, we performed bioassays of phlorotannins, which are considered effective in deterring fouling, by culturing sargassacean blades with N.harveyi carpospores and observed the process by which sargassacean blades remove epiphytes. When the carpospores were incubated with various concentrations of dissolved phlorotannins, settlement and germination were inhibited only at the highest concentrations (>0.1g·L(-1) ), and this effect did not significantly differ among the five sargassacean species. When the carpospores were combined with blades from the five species, many of the spores attached and germinated on every blade. Because N.harveyi penetrated rhizoids into basiphyte tissues, cuticle peeling observed in all five sargassacean species could not remove this epiphyte after germination. However, in S.siliquastrum, the blade tissues around the germlings became swollen and disintegrative, and were removed together with the germlings. The spores normally grew on the dead blades, suggesting that the tissue degradation of S.siliquastrum is triggered by the infection of N.harveyi.

The new species Neosiphonia thailandica sp. nov. (Rhodomelaceae, Rhodophyta) from the Gulf of Thailand

Abstract We describe a new epiphytic red alga Neosiphonia thailandica sp. nov. based on a sample collected from Sri Rasha Harbor in the eastern upper Gulf of Thailand. This species grows epiphytically on Gracilaria fisheri, and it is distinguished from other members of the genus by a combination of morphological features: large and slender thalli with narrow axes (up to 15 cm height and 0.5 mm wide), ecortication, well-developed erect habit, few trichoblasts, and abundant adventitious endogenous branchlets occurring in various positions on the thalli. The morphological distinction of N. thailandica is supported by molecular phylogenetic analyses using partial rbcL sequences. Neosiphonia thailandica is positioned within a major clade of the genus Neosiphonia and clustered with Neosiphonia sphaerocarpa and Polysiphonia forfex.

Does the amphipod fauna associated with epiphytes on kelp (Laminaria hyperborea) change with depth?

The present study showed a differential composition of amphipod fauna on red algae with different morphology. The stipes of Laminaria hyperborea are covered with epiphytes, of which red algae constitute a main group. A rich invertebrate fauna dominated by gastropods and amphipods is associated with the epiphytes. The algae may function as a habitat providing refuge against wave action and predation, or as food. The study was carried out on the southwest coast of Norway. Common epiphytic red algae of different morphology with associated amphipods were sampled at three different depths at three localities with kelp forest (L. hyperborea). Although the total amphipod densities increased with habitat size, the distribution of amphipods on the selected epiphytes differed. Ptilota gunneri is repeatedly feather-branched with a complex branching pattern and has high densities of small amphipods, dominated by Jassa falcata and species from the familiy Stenothoidae. The filamentous epiphyte Polysiphonia elongata had low densities with dominance of Caprellidea species. Densities of amphipods associated with P. elongata increased with depth. The amphipod distribution was patchy on Delesseria sanguinea and P. gunneri in relation to station and depth.

A preliminary annotated checklist of the marine algae and seagrasses of the Wallis Islands (French Overseas Territory of Wallis and Futuna), South Pacific

A total of 194 species of marine algae (14 Cyanobacteria, 41 Chlorophyta, 11 Heterokontophyta and 128 Rhodophyta), as well as three species of seagrasses, represent the first published records for the isolated island of Wallis, South Pacific. The flora has its strongest affinities with Fiji and Rotuma, followed by Samoa and French Polynesia. The lack of diverse habitats and its geographical location are invoked to explain the relatively low species richness compared with localities such as Fiji and Samoa. The flora has a typically tropical component dominated by encrusting coralline red algae, the calcified green algal genera Halimeda, and assemblages of Cyanobacteria. Normally ubiquitous species such as Halimeda discoidea, and the brown algal genera Hydroclathrus, Colpomenia, Rosenvingea, Asteronema, and Chnoospora are notably absent from the island, perhaps due to seasonality and the lack of suitable habitats. The minute epiphytic red alga Acrochaetium kurogii is reported for the first time outside of its type locality in Japan, while two as yet unidentified species of red algae (Gracilaria sp. and Sebdenia sp.) could represent new taxa if further useful material is found.

Use of red algae as hosts by kelp-associated amphipods

To what extent densities of amphipods associated with red algae are related to food value or habitat form and architecture were investigated. Four epiphytic red algae common on kelp stipes (Laminaria hyperborea) were sampled, and the densities of three species of associated amphipods were analysed. The algae were chosen to represent different structures and levels of architectural complexity. Palmaria palmata and Delesseria sanguinea are leaf-shaped, and Ptilota gunneri and Polysiphonia elongata are branched. The algae were later fed to the common epiphyte-associated amphipods Ampithoe rubricata, Jassa falcata and Caprella septentrionalis in no-choice laboratory experiments. Survival and growth were measured. J. falcata was found at the highest densities on P. gunneri and D. sanguinea, C. septentrionalis was found in highest densities on P. elongata, and P. gunneri and A. rubricata were found at the highest densities on P. gunneri. The survival and growth were highest on P. palmata for all amphipods. This indicates that the form and function of the algal host is more important for the distributions of amphipods than the food value. Interspecific distribution differences between amphipods may have been related to differences in their body form and size, as well as to crypsis.

Pyrophyllon and Chlidophyllon (Erythropeltidales, Rhodophyta): two new genera for obligate epiphytic species previously placed in Porphyra, and a discussion of the orders Erythropeltidales and Bangiales

Two new genera, Pyrophyllon and Chlidophyllon, are described to accommodate three species of obligately epiphytic red algae endemic to the New Zealand region, which were previously placed in the genus Porphyra. Although these species all possess rhizoidal holdfasts and packets of spores, and two of the three species produce archeosporangia (characters consistent with the morphological concept of the genus Porphyra), molecular sequence analyses (nuclear small-subunit ribosomal DNA gene) and polysaccharide chemistry data confirm that these epiphytes are more closely related to members of the Erythropeltidales than to the Bangiales. The criteria used to distinguish members of these orders are discussed.

Ultraviolet sunscreen compounds in epiphytic red algae from mangroves

Epiphytic red algae of the order Ceramiales from mangroves and salt marshes (nine species from Bostrychia, three from Stictosiphonia and four from Caloglossa) produce varying levels of the UV-absorbing compounds mycosporine-glycine, shinorine, porphyra-334, palythine, asterina-330 and palythinol, a suite of substances chemically assigned as mycosporine-like amino acids (MAAs). Mean MAA levels varied from 0.02 to 12.8 mg g−1 DW in field-collected and laboratory cultured specimens. While in field samples of Bostrychia montagneiHarvey, Bostrychia radicans (Montagne) Montagne and Caloglossa apomeiotica J.West et G.Zuccarello MAA concentrations were generally higher compared to cultured plants of the same taxa, Bostrychia tenella(Lamouroux) J.Agardh did not show such a difference. Catenella caespitosa (Withering) L.Irvine, Catenella impudica (Montagne) J.Agardh and Catenella nipae Zanardini (Gigartinales, Caulacanthaceae) produce two novel UV-absorbing compounds: MAA-1 (1.4–4.3 mg g −1 DW) and MAA-2 (0.1–1.0 mg g−1 DW), which absorb at 334 nm and 320 nm, respectively. In laboratory culture of Bostrychia moritziana when photosynthetically active radiation (PAR) was increased from 20 to 40 μmol photons m−2 s−1, the total level of palythinol increased by 85% (from 2.0 to 3.7 mg g−1 DW). In a culture of Caloglossa leprieurii when PAR was increased from 40 to 80 μmol m−2 s−1the porphyra-334 content increased by 77% (from 3.1 to 5.5 mg g−1 DW). Extremely high MAA contents of >30 mg g−1 DW were detected in mature tetrasporangial sori prepared from two isolates of laboratory-cultured reproductive Caloglossa apomeiotica compared to vegetative plants (about 10 mg MAAs g−1 DW) indicating tetraspores loaded up with UV-sunscreens. All data demonstrate that mangrove red algae contain high MAA concentrations, particularly the reproductive structures, and hence these compounds may act as biochemical photoprotectants against exposure to UV-radiation.

Mannitol metabolism of the epiphytic mangrove red alga Caloglossa leprieurii (Ceramiales): A long‐term field study

SUMMARYThe concentrations of mannitol and floridean starch were determined in a 1–year field study of the epiphytic red alga Caloglossa leprieurii (Montagne) J. Agardh from warm temperate waters of eastern Australia. Seasonal environmental data for air and water temperature, day length and rainfall were recorded. The mannitol content and the floridean starch content varied significantly between collections but no seasonal responses were observed, nor were the contents correlated with any of the abiotic factors. A possible function of the starch pool as a supply for respiratory substrates under emergent conditions is discussed. All data indicate that productivity and biomass of C. leprieurii are affected by short‐term abiotic and/or biotic conditions rather than controlled directly by seasonally fluctuating environmental factors. In addition, the activity of three highly specific enzymes (mannitol‐1–phosphate dehydroge‐nase, mannitol‐1–phosphatase, mannitol‐dehydroge‐nase) and one non‐specific enzyme (hexokinase), all of which are involved in the mannitol cycle, were measured in cell‐free extracts every 2 weeks. All enzymes showed marked changes in activity over the year, but again no clear patterns emerged, neither with season nor in relationship to one another. On the basis of the results here, C. leprieurii is considered to be a 'season responded rather than a ‘season anticipator’.

The Red Algal Epiphytes Microcladia coulteri Harv. and M. californica Farl. (Rhodophyceae, Ceramiaceae). III. The Effect of Light on Growth, Reproduction and Morphology

Germlings of the epiphytic red algae Microcladia coulteri and M. californica were cultured at three different light intensities in order to observe the effect of irradiance on germination, growth, development of reproductive structures and overall thallus morphology. A light intensity of 25 μE m −2 s −1 was optimal for germination, germling growth and reproduction of both epiphytes. An intensity of 15 μE m −2 s −1 was as effective as 25 μE m −2 s −1 for M. californica but not for M. coulteri, in which the growth rate was significantly slower. At the highest light (50 μE m −2 s −1 ), germlings of both species generally grew as fast as at 25 μE m −2 s −1 but their thalli were covered with short adventitious branches

Interactions between herbivorous fishes and macro-algae on a temperate rocky reef

In a survey of the herbivorous fishes at a number of rocky reef locations in Victoria, Australia, the densities, of the damselfish Parma victoriae (Gunther) and a guild of herbivorous leatherjackets (Monacanthidae) were negatively correlated with the cover of large brown macro-algae. Within sites, these fishes occurred predominantly below a continuous zone of the kelp Ecklonia radiata (J.Ag.), where they fed on a variety of red and green turfing algae. Some damselfish were found on small patches of turf where there were gaps in the kelp canopy. The only herbivorous fishes associated with the kelp were Odax cyanomelas (Richardson), which feeds directly on Ecklonia radiata, and the leatherjacket Penicipelta vittiger (Castelnau), which consumes epiphytic red algae. Direct observations of quadrats at various depths indicated that by far the greatest amount of herbivorous fish feeding occurred below the kelp zone. Experimental kelp clearances in shallow water resulted in a major increase in the feeding by leatherjackets and damselfish, the latter establishing territories on cleared patches. This corresponded with an increase in the abundance of turfing algae following canopy removal. A fine-scale examination of the feeding activity of Parma victoriae and leatherjackets below the kelp line suggested that the damselfish controlled the local use of space by the more wide-ranging leatherjackets. Experimental removal of P. victoriae resulted in a substantial increase in leatherjacket feeding. There was no difference between P. victoriae territories and adjacent areas in terms of the distribution and abundance of algae, suggesting that neither group has a major impact on the benthic flora. The results suggest that large brown macro-algae are key organisms affecting the distribution of herbivorous fishes at a number of spatial scales. Aggressive behaviour by the damselfish also affects local patterns in the dispersion of non-territorial species.

Diet in odacid and aplodactylid fishes from Australia and New Zealand

Diets of a number of temperate-water reef fishes considered to be herbivores were examined by stomach content analysis. Two species of the genus Odax (family Odacidae), O. pullus and O. acroptilus, were investigated. Stomach contents of samples of O. pullus from two times and two localities on the New Zealand coast were dominated by fucoid and laminarian algae. There was evidence of selection of reproductive structures of fucoid algae as an important food source. O. acroptilus collected from the central NSW coast of Australia proved to be a carnivore on small benthic invertebrates. In addition, the stomach contents of a taxon unique to Southern Hemisphere waters, Aplodactylus arctidens (family Aplodactylidae), and of one member of a widespread taxon, Girella tricuspidata (family Girellidae), were examined as a comparison with Odax. Collections of each species were made in northern New Zealand. A. arctidens and G. tricuspidata were facultative herbivores with diets dominated by under storey and epiphytic red algae. These results emphasize the unusual feeding patterns of herbivorous odacids and their importance in the development of general models of piscine herbivory.

A newly discovered host of the sea-grass epiphyte Smithora naiadum (Bangiophyceae, Rhodophyta)

The epiphytic red alga, Smithora naiadum, once thought to occur exclusively on natural (or synthetic) sea-grass blades, has been found to grow on Plocamium cartilagineum, a red alga common in the understory of Phyllospadix scouleri.

Ein Standort der epiphytischen Süßwasser-Rotalge Balbiania investiens(Lenormand) Sirodot 1876 in Mitteleuropa

Summary The rare epiphytic freshwater redalga Balbiania investiens (Lenormand) Sirodot , hitherto known only from Western Europe, was found on Batrachospermum growing in a brooklet of the Harz mountains. The new station enlarges the area of distribution about 11 degrees in eastern direction.

THE DISTRIBUTION OF PHOTOSYNTHATE IN ASCOPHYLLUM NODOSUM AS IT RELATES TO EPIPHYTIC POLYSIPHONIA LANOSA12

SUMMARYThe brown alga Ascophyllum nodosum is not a major source of organic carbon for its epiphytic red alga Polysiphonia lanosa. Plants pulse‐labeled for 24–25 hr with NaH14CO3 were examined for exudation and translocation. The maximum amount of radioactive carbon compounds lost from A. nodosum during this experimental period was less than 0.3% of the total 14C fixed by the alga, and of this amount, only 5% could, have moved through the frond. The remaining fraction of the 14C lost from the thallus was released into the water.The total exudate from A. nodosum was collected for 1 week in a series of flasks of filtered seawater changed at 12‐hr intervals corresponding with the beginning of the light and dark periods, respectively. During 7 days at 15 C only 1.5% of the total 14C originally fixed had been released as radioactive organic carbon, whereas at 5 C, 0.6% of the total 14C fixed was found in the medium. No significant difference in the rate of exudation of organic 14C was observed in light or darkness. After fractionation of the exudate it was found that only 10% of the radioactivity in these exudates was composed of organic acids or amino acids. P. lanosa, on the other hand, is perfectly capable of fixing its own carbon. The photosynthetic rates measured by H14CO3 uptake confirm the observations of Bidwell: 3.96 mg CO2/g/hr (0.09 m mole/g/hr).

Observations on Kylinia Rosulata From S.W. England

A description is given of the minute epiphytic red alga Kylinia rosulata Rosenv. from collections made in the Plymouth area, and from old herbarium material. The diagnostic characters of this and related species are discussed.The minute epiphytic red alga Kylinia rosulata (order Nemalionales, sub class Florideophycidae) was first described by Rosenvinge (1909) from dried specimens of Sporochnus pedunculatus (Huds.) Ag., collected from the Northern Kattegat. Kylinia was observed on the terminal assimilatory filaments of the supporting plant. Since the original description, this small plant has had a somewhat confused history from both the taxonomic and nomenclatural points of view. Feldmann(1963) has recently summarized the available data, and has verified the validity of the genus and species as originally described by Rosenvinge (see also Feldmann, 1958). K. rosulata is characterized by the possession of short prostrate filaments arising from a single attaching cell, each cell containing a parietal chromatophore, and with male plants bearing a hyaline hair-like body—called the ‘androphore’ by Rosenvinge (1909) and ‘spermatocystophore’ by Feldmann (1958).

Occurrence of Falkenbergia on the English Coast

ON April 17, 1949, during the course of a survey of the shore known as the Gates at the southern tip of Lundy, a piece of a Floridean alga, too small to identify with certainty, was collected in order that its population of epiphytic red algae might be examined. It occurred in a pool very near extreme low water springs, the spring tides at this period being some of the biggest of the year.