Bostrychia Scorpioides Research Articles

Isolation and Structure Elucidation of Novel Mycosporine-like Amino Acids from the Two Intertidal Red Macroalgae Bostrychia scorpioides and Catenella caespitosa.

This study presents a phytochemical survey of two common intertidal red algal species, Bostrychia scorpioides and Catenella caespitosa, regarding their MAA (mycosporine-like amino acid) composition, which are known as biogenic sunscreen compounds. Six novel MAAs from Bostrychia scorpioides named bostrychines and two novel MAAs from Catenella caespitosa named catenellines were isolated using a protocol which included silica gel column chromatography, flash chromatography on reversed phase material and semipreparative HPLC (High-Performance Liquid Chromatography). The structure of the novel MAAs was elucidated using NMR (Nuclear Magnetic Resonance) and HR-MS (High-Resolution Mass Spectrometry), and their absolute configuration was confirmed by ECD (Electronic Circular Dichroism). All isolated MAAs possess a cyclohexenimine scaffold, and the metabolites from B. scorpioides are related to the known MAAs bostrychines A-F, which contain glutamine, glutamic acid and/or threonine in their side chains. The new MAAs from C. caespitosa contain taurine, an amino sulfonic acid that is also present in another MAA isolated from this species, namely, catenelline. Previous and new data confirm that intertidal red algae are chemically rich in MAAs, which explains their high tolerance against biologically harmful ultraviolet radiation.

Analysis of the Mycosporine-Like Amino Acid (MAA) Pattern of the Salt Marsh Red Alga Bostrychia scorpioides.

This study presents the validation of a high-performance liquid chromatography diode array detector (HPLC-DAD) method for the determination of different mycosporine-like amino acids (MAAs) in the red alga Bostrychia scorpioides. The investigated MAAs, named bostrychines, have only been found in this specific species so far. The developed HPLC-DAD method was successfully applied for the quantification of the major MAAs in Bostrychia scorpioides extracts, collected from four different countries in Europe showing only minor differences between the investigated samples. In the past, several Bostrychia spp. have been reported to include cryptic species, and in some cases such as B. calliptera, B. simpliciuscula, and B. moritziana, the polyphyly was supported by differences in their MAA composition. The uniformity in the MAA composition of the investigated B. scorpioides samples is in agreement with the reported monophyly of this Bostrychia sp.

Bostrychines A–F, Six Novel Mycosporine-Like Amino-Acids and a Novel Betaine from the Red Alga Bostrychia scorpioides

Various red algae have repeatedly been reported to produce a variety of UV-absorbing mycosporine-like amino acids (MAAs), compounds that are well-known as natural sun-screens, as well as a plethora of betaines, metabolites which contribute to the osmotic balance under salt stress. Among other Rhodophyta, Bostrychia scorpioides, which is thriving as epiphyte on salt marsh plants in Europe and hence experiences extreme environmental conditions such as desiccation, UV-stress and osmotic stress, has barely been investigated for its secondary metabolites. In the present study, seven mycosporine like-amino acids and two betaines were isolated from Bostrychia scorpioides using various chromatographic techniques. Their structures were confirmed by Nuclear Magnetic Resonance (NMR) spectroscopy and High Resolution Mass Spectrometry (HRMS). Six MAAs and one betaine were chemically characterized as new natural products.

Photo-protective compounds in red macroalgae from Brittany: Considerable diversity in mycosporine-like amino acids (MAAs)

To cope with the biotic and abiotic stresses experienced within their environment, marine macroalgae have developed certain defence mechanisms including the synthesis of photo-protective molecules against light and particularly harmful UV radiation. The aim of this study was to screen selected red algae, a highly diverse phylogenetic group, for the production of photo-protective molecules. The pigment content and composition (i.e. chlorophyll-a, phycobiliproteins and carotenoids) and the composition of mycosporine-like amino acids (MAAs) were studied in 40 species of red macroalgae collected in Brittany (France), at two distinct periods (i.e. February and July 2017). A high inter-specific variability was demonstrated in terms of pigment content and MAA composition. Twenty-three potential MAAs were detected by HPLC, and six were identified by LC-MS (i.e. shinorine, palythine, asterina-330, porphyra-334, usurijene and palythene). This is the first study to report on the composition of pigments and MAAs in a diverse group of red seaweeds from Brittany, including some species for which the MAA composition has never been studied before. Nevertheless, the results suggested that some species of red algae are more likely to cope with high levels of light radiation since those species such as Bostrychia scorpioides, Porphyra dioica, Gracilaria vermiculophylla and Vertebrata lanosa are living in environments exposed to higher levels of irradiation, and had various MAAs in addition to their photo-protective pigments.

Understanding the intertidal zonation of two estuarine red macroalgae from ex situ photoacclimative responses

This study investigated the influence of light on the distributional limits of Bostrychia scorpioides and Catenella caespitosa within a low amplitude intertidal zonation in the Palmones estuary, Spain. Changes in photosynthesis- and growth-irradiance curves and pigment content were examined ex situ at irradiances found in their natural habitat (10–230 µmol photons m−2 s−1). The highest maximum photosynthesis rate (Pm) and photosynthetic efficiency (α) were found between 20–40 µmol photons m−2 s−1 in both species. Bostrychia scorpioides, the uppermost intertidal species, had a higher Pm, α, dark respiration rate and light compensation point (Ec) than C. caespitosa at all acclimation irradiances. Net photosynthetic rates measured at their respective acclimation irradiances showed photosynthetic responses of B. scorpioides to be maximized at high irradiances, while in C. caespitosa they did not change. Higher growth rates were obtained in C. caespitosa than in B. scorpioides, which may be related to its lower thallus specific carbon content. When irradiance decreased, the chlorophyll a content of B. scorpioides increased whereas in C. caespitosa R-phycoerythrin increased. Ec for growth of B. scorpioides coincided with the irradiance at its lower distributional limit in the estuary, below which this species showed losses in biomass. However, in C. caespitosa the sustained growth ex situ at saturating irradiances contrasts with its absence from the upper intertidal zone, where similar light regimes occur. We demonstrated that while light clearly restricts the growth of B. scorpioides to the uppermost intertidal zone, this environmental factor would not prevent C. caespitosa from growing at higher levels.

Mechanisms of inorganic carbon acquisition in two estuarine Rhodophyceans: Bostrychia scorpioides (Hudson) ex Kützing Montagne and Catenella caespitosa (Withering) L. M. Irvine.

Marine macroalgae possess a range of mechanisms to increase the availability of CO2 for fixation by ribulose-1,5-bisphosphate carboxylase/oxygenase. Of these, possession of a periplasmic or external carbonic anhydrase and the ability to use bicarbonate ions is widely distributed. The mechanisms of carbon acquisition were studied in two estuarine red macroalgae Bostrychia scorpioides and Catenella caespitosa using a range of techniques. pH-drift and CO2-depletion experiments at constant pH suggested that CO2 is the main source of inorganic carbon in both species. Inhibitors indicated that internal and external carbonic anhydrase were present in both species. Inhibitors also suggested that uptake of bicarbonate is unlikely to be present (P<0.05).

Differential nutrient uptake by two segregated red algae in an estuarine intertidal zone

SÁnchez de Pedro R., Niell F.X. and Carmona R. 2013. Differential nutrient uptake by two segregated red algae in an estuarine intertidal zone. Phycologia 52: 461–471. DOI: 10.2216/13-147.1Bostrychia scorpioides (Rhodophyta: Ceramiales) and Catenella caespitosa (Rhodophyta: Gigartinales) were segregated but slightly overlapping in the narrow intertidal of the Palmones River Estuary (Southern Spain). This study investigated whether there were interspecific differences in nutrient uptake capabilities and how meaningful these were to zonation. Uptake kinetics of ammonium, nitrate, and phosphate were measured over successive time intervals across a range of environmentally realistic concentrations. The interactions between ammonium and nitrate in mixed N source uptake were also tested. Using internal N and P content, turnover rates were calculated for each species for periods of emersion and submersion. Nutrient uptake kinetics were saturable for almost all nutrients except for ammonium in B. scorpioides, which showed surge uptake responses through linear kinetics. Vmax and affinity progressively decreased over 3 h for all nutrients in C. caespitosa and only for phosphate in B. scorpioides. At high dissolved inorganic nitrogen concentrations both species exhibited greater uptake rates for ammonium than nitrate; although, similar N uptake rates were obtained at the low ones. Ammonium contributed to the total N uptake in B. scorpioides to a greater extent; whereas, in C. caespitosa, this only occurred at high N concentrations. In mixed N source uptake experiments, ammonium and nitrate uptake rates by B. scorpioides decreased when the other N source was equimolarly supplied, while in C. caespitosa these interactions were absent. Catenella caespitosa showed a Vmax and affinity for phosphate fourfold higher than for B. scorpioides, with greater interspecific differences than those found for N uptake. Catenella caespitosa renewed internal nutrients faster and was more dependent on the external nutrient supply than B. scorpioides, which can withstand longer periods without nutrient supply due to its slower nutrient turnover rate. Different capabilities for nutrient acquisition in the two species suggested an adaptation to the nutrient availability at each intertidal position.

The marine algal (seaweed) flora of the Azores: additions and amendments

Thirteen species of benthic marine algae are reported new for the isolated mid-Atlantic Azores archipelago and five older records are confirmed. Seven (Bangia atropurpurea, Codium fragile spp. tomentosoides, Ectocarpus fasciculatus, E. siliculosus, Porphyrostromium ciliare, Ulothrix flacca and Ulvaria oxysperma) are widespread amphi-Atlantic species some of which extend in distributional range south to the Canary Islands. Cryptonemia seminervis, Ctenosiphonia hypnoides and Phyllophora sicula are known from the northeastern Atlantic Ocean only and also occur in the Canary Islands. The Azores archipelago is the western limit of distribution of Codium fragile ssp. atlanticum, Bostrychia scorpioides, Bryopsis cupressina, Erythroglossum laciniatum, Haliptilon squamatum and Phyllophora sicula, and the southern limit of C. fragile ssp. atlanticum and E. laciniatum. The tropical species Phyllodictyon anastomosans, Valonia macrophysa and Wurdemannia miniata reach their northern limit of distribution there. Asparagopsis taxiformis is now less common possibly due to competition with the non-native A. armata; subspecies of the non-native C. fragile now occur widely in the Azores. The status of Fucus vesiculosus, Ulva (Enteromorpha) clathrata and Rhizoclonium tortuosum is clarified and other species have been removed from the flora. The continuing addition of new species records for the Azores shows the archipelago to be floristically richer than other Atlantic islands except for the Canary Islands.

Carbon dioxide uptake by Bostrychia scorpioides (Rhodophyceae) under emersed conditions

Inorganic carbon acquisition under emerged conditions was studied in the red macroalga Bostrychia scorpioides by investigating the effects of changes in the pH of the water film surrounding the thalli when emerged and of inhibitors of carbonic anhydrase (CA; EC 4.2.1.1). The CO2 uptake rate increased by approximately 150% when the pH of the water film was changed from 8.1 to 10.5. Acetazolamide (AZ), an inhibitor of the external CA, inhibited CO2 uptake by 50% at pH values higher than 8.7. The effect of ethoxyzolamide (EZ), an inhibitor of both external and internal CA, was more pronounced than that of AZ, inhibiting the CO2 uptake rates by 80% at all the pH values assayed. At pH 10.5, CO2 flux into the cells exceeded by several orders of magnitude the flux supported by the spontaneous dehydration of HCO3 − to CO2 in the water film. From these results it was concluded that the main source of inorganic carbon was atmospheric CO2. The driving force for the flux of atmospheric CO2 into the cell must be the CO2 concentration gradient. Therefore, low internal CO2 concentration might be necessary to account for the CO2 fluxes measured. The function of the internal CA could be to speed up the transformation of CO2 into HCO3 − inside the cell. The function of the external CA could not be fully described from the experiments although it was demonstrated that the external enzyme enhanced the CO2 flux from air to cell surface.

Carbonic anhydrase activity and use of HCO3 − in Bostrychia scorpioides (Ceramiales, Rhodophyceae)

The affinity for HCO3 − and carbonic anhydrase activity (CA; EC 4.2.1.1) were determined in the red macroalga Bostrychia scorpioides. The affinity for HCO3 − was assessed by using three independent methods: the effect of a high pH on photosynthetic rates, photosynthetic conductance for CO2 estimated from the initial slope of photosynthesis rate versus inorganic carbon concentration curves, and the CO2 compensation point. The results obtained from the three methods were consistent in demonstrating that B. scorpioides has a very low affinity for HCO3 −, although a certain capacity for its use must not be ruled out. High activities of both external and internal CA were found. Internal CA activity was 10-fold higher than external. External and internal CA were necessary for photosynthesis at pH values higher than 7·0 because O2 evolution was inhibited after adding acetazolamide and ethoxyzolamide (inhibitors of CA). The effect of changing O2 concentration on photosynthesis was also examined. Bostrychia scorpioides exhibited a high sensitivity to O2′ demonstrating a C3-like photosynthetic gas exchange physiology. Therefore, the high level of CA activity in B. scorpioides was not enough to support a high affinity for HCO3 − and to prevent photorespiration.

Carbonic anhydrase activity and use of HCO3 − in Bostrychia scorpioides (Ceramiales, Rhodophyceae)

The affinity for HCO3 − and carbonic anhydrase activity (CA; EC 4.2.1.1) were determined in the red macroalga Bostrychia scorpioides. The affinity for HCO3 − was assessed by using three independent methods: the effect of a high pH on photosynthetic rates, photosynthetic conductance for CO2 estimated from the initial slope of photosynthesis rate versus inorganic carbon concentration curves, and the CO2 compensation point. The results obtained from the three methods were consistent in demonstrating that B. scorpioides has a very low affinity for HCO3 −, although a certain capacity for its use must not be ruled out. High activities of both external and internal CA were found. Internal CA activity was 10-fold higher than external. External and internal CA were necessary for photosynthesis at pH values higher than 7·0 because O2 evolution was inhibited after adding acetazolamide and ethoxyzolamide (inhibitors of CA). The effect of changing O2 concentration on photosynthesis was also examined. Bostrychia scorpioides exhibited a high sensitivity to O2′ demonstrating a C3-like photosynthetic gas exchange physiology. Therefore, the high level of CA activity in B. scorpioides was not enough to support a high affinity for HCO3 − and to prevent photorespiration.

Incomplete turgor pressure regulation in the “terrestial” red alga, Bostrychia scorpioides (Huds.) Mont.

The red alga, Bostrychia scorpioides, was subjeced to osmotic stresses ranging from hypoosmotic (535 mOsm kg −1) to hyperosmotic conditions (1440 mOsm kg −1). The ionic concentrations of Na +, K +, and Cl − as well as the hexitols d-sorbitol and d-dulcitol increased with increasing salinity. Other ions (Mg 2+, Ca 2+, sulphate and phosphate) did not change in their concentrations with salinity. Turgor pressure, however, was not regained and decreased with increasing salinity. The alga is able to tolerate incomplete turgor regulation, which may be a prerequisite to survive long term dessiccation, a stress condition occurring frequently in the upper supralittoral zone, the natural habitat of this alga.

Survey of freshwater red algae (Rhodophyta) of south-eastern Australia

A survey of rivers and other freshwater habitats in south-eastern Australia has resulted in the description and illustration of 14 species and two forms of red algae. With the exception of the two species of Nothocladus, all the taxa appear to be widespread in warm to cool temperate regions of the world. Three of the species [Chroodactylon ornatum (C.Ag.) Basson, Caloglossa leprieurii (Mont.) J.Ag. and Bostrychia scorpioides (Gmel.) Montagne] occur in brackish and marine habitats, as well as in fresh water. Two species [Hildenbrandia rivularis (Liebm.) J.Ag. and Audouinella hermannii Roth] are members of fundamentally marine genera that have one or a few distinct freshwater representatives. The remaining taxa belong to the genus Compsopogon (Compsopogonaceae, Erythropeltidales) and the family Batrachospermaceae (Nemaliales), which have no marine representatives and probably evolved in fresh water. This latter group consists of Compsopogon coeruleus (Balb.) Montagne, Batrachosperrnum atrum (Huds.) Harvey, B. ectocarpum Sirodot, B. Helminthoideum (Sirod.) Mori (two forms), B. keratophytum Bory, B. virgato-decaisneanum Sirodot, Sirodotia suecica Kylin (two forms), Nothocladus nodosus Skuja and N. lindaueri Skuja. The survey has added six new records to the Australian freshwater red algal flora. Nothocladus nodosus Skuja and N. tasmanicus Skuja are synonymized; N. lindaueri Skuja, previously recorded only from New Zealand, was found to be widely distributed in Victoria. Taxonomic characters in the genus Batrachospermum from Australia, the largest and most difficult group of species encountered, are reviewed.

14C-Assimilate pattern and kinetics of photosynthetic 14CO2-assimilation of the marine red alga Bostrychia scorpioides

Occurrence and metabolism of dulcitol and sorbitol in the marine red alga Bostrychia scorpioides (Huds.) Mont. (Ceramiales: Rhodomelaceae) were investigated. Both hexitols are rapidly (14)C-labelled during photosynthesis in a H(14)CO3-seawater medium and are accumulated at comparable rates. The absolute quantity amounts to about 3.2% on a dry weight basis; the percentage of (14)C-labelling after 60 min is 30% for dulcitol and 40% for sorbitol. Additionally small amounts of free [(14)C] glucose were found. Pulse labelling experiments and changes in specific activity provide evidence that both hexitols are rapidly available respiratory substrates, which, however, are probably not interconvertible with polymeric compounds. Some chemotaxonomic aspects are discussed.

The New Zealand Species of Bostrychia Related to Bostrychia scorpioides Mont.

The New Zealand Species of Bostrychia Related to Bostrychia scorpioides Mont.

Chemistry of the Red and Brown Algæ

IN view of the fact that a study of the literature on the red and brown algae revealed considerable uncertainty as to whether true cellulose occurs in these plants, the following seaweeds were examined for cellulose by the usually accepted methods:—among the red algae, Corallina officinalis, Bostrychia scorpioides, Chondrus crispus, Rhodymenia palmata ; among the brown algae, Laminaria saccharina, L. digitata, Fucus serratus, F. vesiculosus, Ascophyllum nodosum, Pelvetia canaliculata and P. canaliculata, forma libera.

Occurrence of Dulcitol in a Red Seaweed

THE occurrence of mannitol has long been recorded in seaweeds, but, so far as the literature reveals, its distribution is confined to the brown algae, and hitherto it has been the only representative of the sugar alcohols known to occur in the algae. We have recently had occasion to examine extracts of the red seaweed Bostrychia scorpioides, which grows on the salt marsh at Blakeney Point; from this material we were able to isolate, in crystalline form, the isomeric alcohol dulcitol. As this is the first recorded observation of this substance in algae, we are proposing to examine a number of other red algae, with the view of determining whether they also contain dulcitol, or whether we were dealing with an exceptional case. A fuller account of the experimental work will, it is hoped, appear before long in the Biochemical Journal.