Marina Morabito

The Mediterranean Red Alga Asparagopsis: A Source of Compounds against Leishmania

Crude extracts and column fractions from the red algae Asparagopsis taxiformis and A. armata from the Strait of Messina (Italy) were screened for the production of antimicrobial compounds. Extracts from both species revealed remarkable antiprotozoal activity against Leishmania, revealing such algae as a great source of natural antiprotozoal products.

Brown seaweed pigment as a dye source for photoelectrochemical solar cells

Chlorophylls based-dyes obtained from seaweeds represent attractive alternatives to the expensive and polluting pyridil based Ru complexes because of their abundance in nature. Another important characteristic is that the algae do not subtract either cropland or agricultural water, therefore do not conflict with agro-food sector. This pigment shows a typical intense absorption in the UV/blue (Soret band) and a less intense band in the red/near IR (Q band) spectral regions and for these reasons appear very promising as sensitizer dyes for DSSC. In the present study, we utilized chlorophylls from samples of the brown alga Undaria pinnatifida as sensitizer in DSSCs. The dye, extracted by frozen seaweeds and used without any chemical purification, showed a very good fill factor (0.69). Even the photelectrochemical parameters if compared with the existent literature are very interesting.

Potential Use of Polysaccharides from the Brown Alga Undaria pinnatifida as Anticoagulants

Undaria pinnatifida (U. pinnatifida) is a highly invasive species and has caused concern all over the world because it has invaded coastal environments, has the potential to displace native species, significantly alters habitat for associated fauna, and disturbs navigation. Any attempt to eradicate it would be futile, owing to the elusive, microscopic gametophyte, and because the alga thrives in sites rich in anthropic activities. Venice Lagoon is the largest Mediterranean transitional environment and the spot of the highest introduction of non-indigenous species, including U. pinnatifida, which is removed as a waste. We demonstrated that polysaccharide extracts from U. pinnatifida have an anticoagulant effect on human blood in vitro and are not cytotoxic. The results obtained by PT (normal values 70-120%) and APTT (normal values 28-40s) assays were significantly prolonged by the polysaccharide extracts of U. pinnatifida, therefore algal extracts are ideal candidates as antithrombotic agents.

Evaluation of anticoagulant activity of two algal polysaccharides

Abstract Marine algae are important sources of phycocolloids like agar, carrageenans and alginates used in industrial applications. Algal polysaccharides have emerged as an important class of bioactive products showing interesting properties. The aim of our study was to evaluate the potential uses as anticoagulant drugs of algal sulphate polysaccharides extracted from Ulva fasciata (Chlorophyta) and Agardhiella subulata (Rhodophyta) collected in Ganzirri Lake (Cape Peloro Lagoon, north-eastern Sicily, Italy). Toxicity of algal extracts through trypan blue test and anticoagulant action measured by activated partial thromboplastin time (APTT), prothrombin time (PT) test has been evaluated. Algal extracts showed to prolong the PT and APTT during the coagulation cascade and to avoid the blood coagulation of samples. Furthermore, the algal extracts lack toxic effects towards cellular metabolism and their productions are relatively at low cost. This permits to consider the algae as the biological source of the future.

Molecular systematics and phylogenetics of Gracilariacean species from the Mediterranean Sea

Mediterranean reports of Gracilariaceae species, in particular those assigned to the G. verrucosa complex, were re-examined with the use of molecular tools, in order to verify their systematic position and better understand their distribution. Within this complex, we recognized four distinct taxa: Gracilariopsis longissima, Gracilaria gracilis, Gracilaria longa and a possible new species. The rbcL gene sequences, together with those of other terete Mediterranean entities, were included in a broad molecular phylogeny of the family. The reproductive characters of the studied taxa do not fit completely with published hypothesis on the generic and intrageneric relationships, suggesting that the anatomy of some subgroups should be better characterized.

A Re-Assessment of Reproductive Anatomy and Postfertilization Development in the Systematics of Grateloupia (Halymeniales, Rhodophyta)

Abstract The red algal family Halymeniaceae has been recently the subject of taxonomic revisions based strictly on molecular data. As a result, the number of genera ascribed to it has been decreasing and many generic definitions changed profoundly owing to inconsistencies in diacritical vegetative and particularly reproductive characters in standard literature. Reproductive uniformity within this family has been claimed since the late 19th century and is generally supported by recent authors. In this study we report on consistent significant differences in the architecture of carpogonial and auxiliary cell ampullae, as well as in early postfertilization events, among Mediterranean species currently assigned to the genus Grateloupia C. Agardh and provide new interpretations of these features. We recognize several distinct types of ampullae and postfertilization events that distinguish groups of species, these groups proving to be strongly supported by rbcL phylogenies. As a result we conclude that the genus Grateloupia as presently circumscribed should be segregated into multiple genera. In addition to Grateloupia sensu stricto, we resurrect Dermocorynus P.L. Crouan et H.M. Crouan, Pachymeniopsis Y. Yamada ex S. Kawabata, Phyllymenia J. Agardh and Prionitis J. Agardh, all of which have been subsumed in Grateloupia by previous authors. New genera based on our anatomical and rbcL results for G. doryphora (Montagne) M. Howe, G. subpectinata Holmes and G. proteus Kützing will be described in subsequent papers.

Taxonomic Considerations of a Foliose Grateloupia Species from the Straits of Messina

Grateloupia turuturu Yamada is the currently accepted name for the invasive red alga that is present on coasts of the North Atlantic. Previously considered as G. doryphora (Montagne) M.A. Howe, populations of this invasive species were examined and their taxonomic position revised using molecular and morphological techniques. It was also thought that similar invasive populations in the Mediterranean should be identified as G. turuturu. This investigation used rbcL based molecular analyses to clarify the taxonomic position of Grateloupia “doryphora’ from the Straits of Messina. Our results indicate that this population is neither G. doryphora nor G. turuturu. It was placed separately in all analyses and grouped consistently with other Grateloupia species from the Pacific. On the basis of molecular data from this and previous investigations, it is evident that the status of the foliose Atlantic and Mediterranean entities is still unclear and a re-evaluation of the old names connected to them should be undertaken.

Sexual and asexual reproduction in a freshwater population of Bangia atropurpurea (Bangiales, Rhodophyta) from eastern Sicily (Italy)

Abstract The life history of Bangia atropurpurea (Bangiales, Rhodophyta) from the Alcantara River (Sicily, Italy) was studied in the field and laboratory. An alternation between a macroscopic phase and a microscopic filamentous conchocelis phase was found, and spermatia and carpogonia are described for the first time in a freshwater population of the species. Endosporangia have also been discovered on gametophytic plants in culture. In addition, the conchocelis phase produced either conchosporangia or monosporangia, and reproduction by fragmentation was common. Sexuality was indicated by chromosome counts of n = 3 and 2n =6 in gametophytes and sporophytes, respectively; resting cells were observed in both.

Two novel species of Yonagunia (Halymeniales, Rhodophyta) were uncovered in the South of Madagascar during the Atimo-Vatae Expedition

Abstract Yonagunia, a genus of the red algal order Halymeniales, has never been recorded in the Western Indian Ocean. In this study, we used molecular assisted alpha taxonomy to assess the diversity of the marine algal flora of southern Madagascar. A combination of COI-5P and rbcL sequences, used as a DNA-barcode and phylogenetic marker respectively, revealed two species of Yonagunia from the Toliara region in the South of Madagascar. One species, is described a species new to science, Yonagunia atimo-vatae sp. nov. Sequences of the other species, matched of Polyopes ligulata, but it was resolved within the genus Yonagunia rather than Polyopes. Hence, a new combination Yonagunia ligulata comb. nov. is established.

The Mediterranean Endemic New genus Felicinia (Halymeniales, Rhodophyta) Recognized by a Morphological and Phylogenetic Integrative Approach

Abstract Recently, DNA phylogenies resulted in the transfer of some species of the halymeniacean genus Aeodes, namely A. orbitosa and A. ulvoidea, to the genus Pachymenia leaving the former supposedly as a monotypic genus based on the type species, A. nitidissima. Nevertheless, that work overlooked the presence of A. marginata, a red foliaceus alga endemic to the Mediterranean Sea with a convoluted nomenclatural history. In the present study, we provided a thorough description of A. marginata based on both anatomical and molecular data and inferred its phylogenetic relationships among halymeniacean genera using both chloroplastic (rbcL) and nuclear genes (LSU). Based on our data, A. marginata allied with Halymenia, Cryptonemia, and associated genera rather than with the generitype A. nitidissima, and presented a unique set of characters deserving the status of genus within the Halymeniaceae. Therefore, we proposed the new genus Felicinia based on Felicinia marginata comb. nov. A description of the multiaxial vegetative of F. marginata construct was provided, highlighting a unique characteristic among red algae: the presence, in the medulla, of peculiar oblique multicellular filaments connecting periclinal filaments. These filaments are produced secondarily as branches from axial filaments and are possibly homologous to the anticlinal filaments observed in the medulla of Halymenia.