G. Genovese

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.

The Mediterranean red alga Asparagopsis taxiformis has antifungal activity against Aspergillus species

The red algae Asparagopsis taxiformis collected from the Straits of Messina (Italy) were screened for antifungal activity against Aspergillus species. EUCAST methodology was applied and extracts showed antifungal activity against A. fumigatus, A. terreus and A. flavus. The lowest minimum inhibitory concentrations observed were <0.15 mg ml−1 and the highest were >5 mg ml−1 for Aspergillus spp. tested. Agar diffusion assays confirmed antifungal activity of A. taxiformis extracts in Aspergillus species.

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.

Preliminary Study on the In vitro and In vivo Effects of Asparagopsis taxiformis Bioactive Phycoderivates on Teleosts

Several compounds from marine organisms have been studied for their potential use in aquaculture. Among the red algae, Asparagopsis taxiformis is considered one of the most promising species for the production of bioactive metabolites with numerous proposed applications. Here, the in vitro antibacterial activity, the easy handling and the absence of adverse effects on marine fish species are reported. Depending on the seasonal period of sampling, ethanol extracts of A. taxiformis exhibited significantly different inhibitory activity against fish pathogenic bacteria. The extract obtained in late spring showed strong antibacterial activity against Aeromonas salmonicida subsp. salmonicida, Vibrio alginolyticus, and V. vulnificus, and moderate activity against Photobacterium damselae subsp. damselae, P. damselae subsp. piscicida, V. harveyi and V. parahaemolyticus. Sea bass and gilthead sea bream were fed with pellets supplied with the alga and algal extracts. The absence of undesired effects on fish was demonstrated. Hematological and biochemical investigations allowed to confirm that the whole alga and its extracts could be proposed for a future application in aquaculture.

Effectiveness of red alga Asparagopsis taxiformis extracts against Leishmania infantum

Abstract Leishmaniasis is a disease with a worldwide distribution affecting both humans and animals. There is a need to identify and develop new drugs for the treatment of leishmaniasis. This study showed that crude ethanolic extracts of the red alga Asparagopsis taxiformis have a powerful effect against L. infantum, the prevalent species of the genus Leishmania in the Mediterranean basin. L. infantum demonstrated decreased vitality with increasing concentration of the algal extracts. At a concentration of 40 μg/mL, the extracts achieved 100% mortality of the parasite and the LD50 value was 25 μg/mL for promastigotes and 9 μg/mL for amastigotes. Algal extracts caused morphological alterations and apoptosis in Leishmania cells. The potential cytotoxic action of crude extracts was investigated by a MTT viability assay on DH82 and Vero cell lines but there was no cytotoxic effect. The potential of red alga A. taxiformis metabolites as anti-leishmanial agents merits further pharmacological investigation.

A DNA Barcoding Survey of Ulva (Chlorophyta) in Tunisia and Italy Reveals the Presence of the Overlooked Alien U. ohnoi

Abstract The cosmopolitan genus Ulva Linnaeus includes species of green macroalgae found in marine, brackish and some freshwater environments. Although there is a wide literature for the determination of Ulva taxa in Europe, they are among the most problematic algae to accurately identify, because they have few distinctive features, as well as a high intraspecific variation. At present, the knowledge of both diversity and distribution of the genus Ulva in the Mediterranean Sea is almost entirely based on morphological studies and there is only a few published papers dealing with molecular data. Tunisia has a key position in the Mediterranean and constitutes a transition area with a rich habitat diversity between eastern and western basins. The latest inventory of marine macrophytes dates back to 1987, updated in 1995. The aim of the present paper is to provide a molecular-assisted alpha taxonomy survey of Ulva spp. along Tunisian coasts, in comparison with a few Italian sites, using the tufA marker. Nine genetic species groups were resolved, including the non indigenous species Ulva ohnoi, newly reported for Tunisia. The actual picture of the taxonomy of Ulva spp. in the Mediterranean as a whole is far to be clarified and the present data on Tunisian collections aim to be a step towards its clarification. This paper is the first DNA barcoding study on green macroalgae in Tunisia and it contributes to add records to the Barcode Of Life Data Systems which are publically available.