Red Alga Peyssonnelia Research Articles

Peyssonnosides A-B, Unusual Diterpene Glycosides with a Sterically Encumbered Cyclopropane Motif: Structure Elucidation Using an Integrated Spectroscopic and Computational Workflow.

Two sulfated diterpene glycosides featuring a highly substituted and sterically encumbered cyclopropane ring have been isolated from the marine red alga Peyssonnelia sp. Combination of a wide array of 2D NMR spectroscopic experiments, in a systematic structure elucidation workflow, revealed that peyssonnosides A–B (1–2) represent a new class of diterpene glycosides with a tetracyclo [7.5.0.01,10.05,9] tetradecane architecture. A salient feature of this workflow is the unique application of quantitative interproton distances obtained from the rotating frame Overhauser effect spectroscopy (ROESY) NMR experiment, wherein the β-d-glucose moiety of 1 was used as an internal probe to unequivocally determine the absolute configuration, which was also supported by optical rotatory dispersion (ORD). Peyssonnoside A (1) exhibited promising activity against liver stage Plasmodium berghei and moderate antimethicillin-resistant Staphylococcus aureus (MRSA) activity, with no cytotoxicity against human keratinocytes. Additionally, 1 showed strong growth inhibition of the marine fungus Dendryphiella salina indicating an antifungal ecological role in its natural environment. The high natural abundance and novel carbon skeleton of 1 suggests a rare terpene cyclase machinery, exemplifying the chemical diversity in this phylogenetically distinct marine red alga.

Physiological Responses of the Mediterranean Subtidal Alga Peyssonnelia squamaria to Elevated CO2

The ecological consequences of ocean acidification are unclear due to varying physiological properties of macroalgae and species-specific responses. Therefore, in the present study, we used a laboratory culture experiment to analyse the eco-physiological responses of the Mediterranean subtidal red alga Peyssonnelia squamaria to CO2-induced lower pH. Our results showed an increase in the photosynthetic performance and growth rate of P. squamaria, despite the reduction in CaCO3 content in the low pH treatment. According to our results, we believe that samples exposed to elevated CO2 could be regulated own nitrogen metabolism to support increased growth rate and it may be down-regulated nitrate uptake. As a result, we hypothesize that P. squamaria may benefit from ocean acidification.

Structure and biological evaluation of novel cytotoxic sterol glycosides from the marine red alga Peyssonnelia sp.

Bioactivity-guided fractionation of the extract from a Fijian red alga Peyssonnelia sp. led to the isolation of two novel sterol glycosides 19- O-β- d-glucopyranosyl-19-hydroxy-cholest-4-en-3-one ( 1) and 19- O-β- d- N-acetyl-2-aminoglucopyranosyl-19-hydroxy-cholest-4-en-3-one ( 2), and two known alkaloids indole-3-carboxaldehyde ( 3) and 3-(hydroxyacetyl)indole ( 4). Their structures were characterized by 1D and 2D NMR and mass spectral analysis. The sterol glycosides inhibited cancer cell growth with mean IC 50 values (for 11 human cancer cell lines) of 1.63 and 1.41 μM for 1 and 2, respectively. The most sensitive cancer cell lines were MDA-MB-468 (breast) and A549 (lung), with IC 50’s in of 0.71–0.97 μM for 1 and 2. Modification of the sterol glycoside structures revealed that the α,β-unsaturated ketone at C-3 and oxygenation at C-19 of 1 and 2 are crucial for anticancer activity, whereas the glucosidic group was not essential but contributed to enhanced activity against the most sensitive cell lines.

Ecological leads for natural product discovery: novel sesquiterpene hydroquinones from the red macroalga Peyssonnelia sp.

Pharmacologically-motivated marine natural product investigations have yielded a large variety of structurally unique compounds with interesting biomedical properties, but the natural roles of these molecules often remain unknown. While secondary metabolites may function as antimicrobial chemical defenses, few studies have examined this hypothesis. In the present investigation, chromatographic fractions from 69 collections of Fijian red macroalgae representing at least 43 species were evaluated for growth inhibition of three microbial pathogens and saprophytes of marine macrophytes. At least one microbe was suppressed by fraction(s) of all evaluated algae, suggesting that antimicrobial defenses are common among tropical seaweeds. From these leads, peyssonoic acids A–B ( 1– 2), novel sesquiterpene hydroquinones, were isolated from the crustose red alga Peyssonnelia sp. At ecologically realistic concentrations, both compounds inhibited growth of Pseudoalteromonas bacteriolytica, a bacterial pathogen of marine algae, and Lindra thalassiae, a fungal pathogen of marine algae, and exhibited modest antineoplastic activity against ovarian cancer cells. The peyssonoic acids included one novel carbon skeleton and illustrated the utility of ecological studies in natural product discovery.

Characterization of the crustose red alga Peyssonnelia japonica (Rhodophyta, Gigartinales) and its taxonomic relationship with Peyssonnelia boudouresquei based on morphological and molecular data

SUMMARYThe vegetative and reproductive morphology of the crustose red alga Peyssonnelia japonica (Segawa) Yoneshigue was re‐examined based on the holotype specimen and recent collections from various localities in Japan, including the type locality, and Hawaii. This species is characterized by the following features: thallus with appressed margins, perithallial filaments arising from the entire upper surface of each hypothallial cell (the Peyssonnelia rubra‐type), easily separable perithallial filaments in a gelatinous matrix, hypothallial filaments arranged in parallel rows, unicellular rhizoids, hypobasal calcification, gonimoblasts derived mainly from connecting filaments, and spermatangia produced in a series of whorls comprised of one to four paired spermatangia surrounding each central cell (the Peyssonnelia dubyi‐type). In addition to these features, the dimensions of the vegetative and reproductive structures of Peyssonnelia boudouresquei Yoneshigue described from Brazil were consistent with those of P. japonica. Molecular phylogenetic analyses using partial 26S rDNA, rbcL, and cox2‐3 spacer DNA sequences also supported the monophyly of P. japonica (from 16 localities in Japan and one locality in Hawaii) and P. boudouresquei (from two localities in Brazil). Therefore, P. boudouresquei may be a taxonomic synonym of P. japonica. However, considering the relatively high sequence divergences between the two taxa (2.1–2.5% in partial 26S rDNA, 5.9–6.7% in rbcL, and 5.8–6.7% in cox2‐3 spacer), and the relatively limited geographic sampling ranges, we reserve the taxonomic conclusion until further morphological and genetic data of the specimens from other geographic areas connecting Japan and Brazil become available.

Associational resistance mediates predator--prey interactions in a marine subtidal system

There is a growing awareness of the role that indirect interactions play in influencing food webs and ecosystem structure. In this study, the hypothesis that crustose algal epibionts provide gastropods associational resistance from predation was investigated through field surveys and laboratory feeding assays. In rocky low intertidal ⁄shallow subtidal systems in the northeast Pacific, several species of crustose algae (the red alga Peyssonnelia meridionalis and crustose corallines) can colonize the shells of living Tegula brunnea snails. The growth patterns of these epibiontic crustose algae allow them to cover their host’s surface completely, which may, in turn, protect their hosts from predation. A multi-site field survey of T. brunnea revealed that >60% of snails were at least 75% covered with one or more species of crustose algae, with 35% fully covered, indicating that this is common in the field. Laboratory feeding assays revealed that sea stars, a primary predator of T. brunnea, distinguished among snails with different shell coverings; Pisaster consumed nearly three times as many bare (i.e. no crustose algae) snails as those covered with Peyssonnelia, while Pycnopodia consumed four times as many bare snails as those covered with crustose corallines. These results suggest that epibiont crustose algae can benefit their hosts via associational resistance; this finding may have implications for the role of associational resistance in trophic interactions.

Verosphacela silvae sp. nov. (Onslowiaceae, Phaeophyceae) from the Mediterranean Sea

SUMMARYWe describe Verosphacela silvae sp. nov., from the Mediterranean Sea. It consists of horizontal filaments living on the lower face of the red alga Peyssonnelia rubra (Greville) J. Agardh, from which erect filaments up to 1.5 mm high rise and grow upright after passing through the thallus of the supporting species. There are both horizontal and erect filaments growing by apical cells. In the subapical cells, 1–2 longitudinal divisions occur (more frequently in the erect filaments) but no secondary transverse divisions occur. Erect filaments bear lateral propagules on a stalk of one to three (rarely more) cells. Propagules, with neither apical cells nor arms, consist of seven cells. Zoidangia are borne at the apex of erect laterals. The new species differs from V. ebrachia Henry mainly in habit, propagules and zoidangia. In addition, distinct from V. ebrachia, filaments of V. silvae never penetrate between the cuticle and the cell wall of the supporting alga. Moreover, propagules of V. silvae consist of seven cells, whereas those of V. ebrachia consist of 9–13 cells, and zoidangia are terminal on laterals in V. silvae, whereas in V. ebrachia they are sessile on both axes and laterals.

A new crustose red alga Peyssonnelia rumoiana (Rhodophyta, Gigartinales) from Japan

SUMMARY The marine red alga Peyssonnelia rumoiana Kato et Masuda, sp. nov. (Peyssonneliaceae, Gigartinales) is described from warm- and cold-temperate regions in Japan. It is principally characterized by having hypo-thallial filaments comprising a polyflabelate layer, proximal perithallial cells arising from the whole upper surface of each hypothallial cell (Peyssonnelia rubra-type anatomy) and closely packed in a firm matrix, the production of two filaments from the proximal perithallial cell, unicellular rhizoids, appressed crust margins and hypobasal calcification. The alga is distinguished from related species by: (i) its conspicuously elevated cystocarpic (100–150 μm high) and tetrasporangial (80–110 μm high) nemathecia; (ii) tetrasporangia with or without a unicellular pedicel; and (iii) large (25–45 μm in diameter by 70–115 μm in length) tetrasporangia and (iv) the production of double chains of spermatangia (Peyssonnelia harveyana-type spermatangial development).

A morphological study of Peyssonnelia meridionalis (Gigartinales, Rhodophyta), with discussion of spermatangial types within the genus

Vegetative and reproductive features of the red alga Peyssonnelia meridionalis (Peyssonneliaceae, Gigartinales) are reported on the basis of material collected in Hokkaido, Japan. It is characterized vegetatively by tightly appressed margins, the basal layer (hypothallus) consisting of little-branched filaments which are arranged in parallel, the erect perithallial filaments arising from the whole upper surface of each hypothallial cell, and unicellular rhizoids. Gametophytes are monoecious and produce female and male reproductive structures in separate nemathecia that are distinctly (but slightly) elevated. Gonimoblasts issue from the connecting filament that develops from the suprabasal cell of carpogonial branches, which contacts with a fertilized carpogonium by a connecting cell. Spermatangial nemathecia consist entirely of spermatangial filaments, which bear a series of one to four paired spennatangia that form a whorl surrounding each central cell. Tetrasporangia with a one-celled pedicel are terminal on a perithallial filament of distinctly (but slightly) elevated nemathecia and are associated with simple paraphyses.

Sexually reproducing populations of Peyssonnelia rosenvingii (Gigartinales, Rhodophyta) in the North Pacific

Sexually reproducing populations of the marine red alga Peyssonnelia rosenvingii Schmitz (Peyssonneliaceae, Gigartinales), for which only spermatangia and monosporangia, borne on the same thalli, have previously been known, are reported from the cold-temperate region of Japan. Plants are reproductive in late autumn and early winter. Each carpogonial branch consists of four or five cells, and the suprabasal cell of three- to five-celled auxiliary cell branches functions as an auxiliary cell. The absence of spermatangia and the presence of large, non-reproductive plants during the fertile season suggest that the spermatangial sori are ephemeral. After presumed fertilization a connecting filament develops from the hypogynous cell and runs in the horizontal plane. It branches irregularly and fuses with several auxiliary cells, forming several gonimoblasts along its length. Each gonimoblast produces five to eight carposporangial chains in conspicuously elevated nemathecia up to 350 µm high. Tetrasporangia are also formed in similar nemathecia up to 300 µm high and have three- to eight-celled pedicels.

Temperate Carbonates on a Modern, Low-Energy, Isolated Ramp: The Balearic Platform, Spain

ABSTRACT This paper presents a depositional model for a temperate, low-energy carbonate ramp based on descriptive studies of five areas around the Balearic Islands of Mallorca and Menorca. This low-energy ramp differs significantly from other present-day temperate carbonate platforms that are primarily high-energy open shelves. It is characterized by the following lithofacies (from shore to basin): (1) lagoon, (2) barrier island, (3) shallow subtidal, (4) inner ramp, (5) middle ramp, and (6) distal ramp. Subaqueous carbonate dunes are present near slope breaks off Menorca and Cabrera, but they are not representative of the entire ramp. Balearic ramp sediments differ in composition, texture, biology, and degree of cementation from those on modern low-energy, tropical ramps. Balearic ramp carbon tes lack ooids and peloids, hermatypic coral buildups, and calcareous green algae (except in one restricted bay where Halimeda is relatively common). Red algal sands and gravels extend to depths of up to 90 m, and are coarser than their strandplain-equivalent lime sands. Skeletal allochems consist of the bryomol-rhodalgal association, marine cementation is rare, and the carbonate fraction of deep-water muds is mainly Mg-calcitic and calcitic in composition. Aragonite is rare. Except for the red alga Peyssonnelia, which is composed of aragonite, it is neither a dominant skeletal constituent nor common as a cement. The Mediterranean Sea off Mallorca and Menorca is a low-energy, temperate, oligotrophic, clear-water environment. The depositional model for the region is an isolated platform configured as a homoclinal ramp. Ancient counterparts of the Balearic ramp are present in the Neogene of the Mediterranean Tethys and the Paratethys, and though the constituents of fossil assemblages vary with time, the biota of the Balearic ramp, such as bryozoans, red algae, echinoderms, and mollusks, ranges from the Paleozoic Era to the present. Echinodermal bryomols passing to basinal muds on carbonate ramps are particularly characteristic of the Early Carboniferous in North America and Europe. This suggests that the Balearic Islands temperate ramp may be more representative of some ancient carbonate sequenc s than either temperate, high-energy, open shelves or tropical ramps in the present oceans.