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- Analysis of the Use of Cylindrospermopsin and/or Microcystin-Contaminated Water in the Growth, Mineral Content, and Contamination of Spinacia oleracea and Lactuca sativaPublication . Llana-Ruiz-Cabello, Maria; Jos, Angeles; Cameán, Ana; Oliveira, Flavio; Barreiro, Aldo; Machado, Joana; Azevedo, Joana; Pinto, Edgar; Almeida, Agostinho; Campos, Alexandre; Vasconcelos, Vitor; Freitas, MarisaCyanobacteria and cyanotoxins constitute a serious environmental and human health problem. Moreover, concerns are raised with the use of contaminated water in agriculture and vegetable production as this can lead to food contamination and human exposure to toxins as well as impairment in crop development and productivity. The objective of this work was to assess the susceptibility of two green vegetables, spinach and lettuce, to the cyanotoxins microcystin (MC) and cylindrospermopsin (CYN), individually and in mixture. The study consisted of growing both vegetables in hydroponics, under controlled conditions, for 21 days in nutrient medium doped with MC or CYN at 10 μg/L and 50 μg/L, or CYN/MC mixture at 5 + 5 μg/L and 25 + 25 μg/L. Extracts from M. aeruginosa and C. ovalisporum were used as sources of toxins. The study revealed growth inhibition of the aerial part (Leaves) in both species when treated with 50µg/L of MC, CYN and CYN/MC mixture. MC showed to be more harmful to plant growth than CYN. Moreover spinach leaves growth was inhibited by both 5 + 5 and 25 + 25 µg/L CYN/MC mixtures, whereas lettuce leaves growth was inhibited only by 25 + 25 µg/L CYN/MC mixture. Overall, growth data evidence increased sensitivity of spinach to cyanotoxins in comparison to lettuce. On the other hand, plants exposed to CYN/MC mixture showed differential accumulation of CYN and MC. In addition, CYN, but not MC, was translocated from the roots to the leaves. CYN and MC affected the levels of minerals particularly in plant roots. The elements most affected were Ca, K and Mg. However, in leaves K was the mineral that was affected by exposure to cyanotoxins.
- Analysis of the use of microcystin-contaminated water in the growth and nutritional quality of the root-vegetable, Daucus carotaPublication . Machado, J.; Azevedo, J.; Freitas, Marisa; Pinto, Edgar; Almeida, A.; Vasconcelos, V.; Campos, A.Toxic cyanobacterial blooms are often observed in freshwaters and may reflect the increased eutrophication of these environments and alterations in climate. Cyanotoxins, such as microcystins (MCs), are an effective threat to many life forms, ranging from plants to humans. Despite the research conducted to date on cyanotoxins, the risks associated to the use of contaminated water in agriculture require further elucidation. To tackle this aim, a research was conducted with the root-vegetable Daucus carota. The specific aims of this work were the following: (i) to evaluate the effects of MC-LR on the plant growth and photosynthesis; (ii) to evaluate the nutritional quality of carrot roots; and (iii) to measure bioaccumulation. To this purpose, young carrots were grown in soil during 1 month in natural conditions and exposed to Mycrocystis aeruginosa aqueous extracts containing environmentally realistic concentrations of MC-LR (10 and 50 MC-LR μg/L). The results showed that MC-LR may decrease root growth after 28 days of exposure to 50 μg/L and increase photosynthetic efficiency. We also observed changes in mineral and vitamin content in carrots as a result of the exposure to contaminated water. Moreover, MC-LR was detected in carrot roots by ELISA at very low concentration 5.23 ± 0.47 ng MC eq./g FW. The soil retained 52.7 % of the toxin potentially available for plants. This result could be attributed to MC-LR adsorption by soil particles or due to microbial degradation of the toxin. We conclude that the prolonged use of MC-LR-contaminated water may affect crop growth, alter the nutritional value of vegetable products, and potentiate contamination.
- Antimicrobial and cytotoxic assessment of marine cyanobacteria - synechocystis and synechococcusPublication . Martins, Rosario; Ramos, Miguel; Herfindal, Lars; Sousa, José; Skærven, Kaja; Vasconcelos, VítorAqueous extracts and organic solvent extracts of isolated marine cyanobacteria strains were tested for antimicrobial activity against a fungus, Gram-positive and Gram-negative bacteria and for cytotoxic activity against primary rat hepatocytes and HL-60 cells. Antimicrobial activity was based on the agar diffusion assay. Cytotoxic activity was measured by apoptotic cell death scored by cell surface evaluation and nuclear morphology. A high percentage of apoptotic cells were observed for HL-60 cells when treated with cyanobacterial organic extracts. Slight apoptotic effects were observed in primary rat hepatocytes when exposed to aqueous cyanobacterial extracts. Nine cyanobacteria strains were found to have antibiotic activity against two Gram-positive bacteria, Clavibacter michiganensis subsp. insidiosum and Cellulomonas uda. No inhibitory effects were found against the fungus Candida albicans and Gram-negative bacteria. Marine Synechocystis and Synechococcus extracts induce apoptosis in eukaryotic cells and cause inhibition of Gram-positive bacteria. The different activity in different extracts suggests different compounds with different polarities.
- Antitumor activity of hierridin B, a cyanobacterial secondary metabolite found in both filamentous and unicellular marine strainsPublication . Leão, Pedro N.; Costa, Margarida; Ramos, Vitor; Pereira, Alban R.; Fernandes, Virgínia C.; Domingues, Valentina F.; Gerwick, William H.; Vasconcelos, Vítor; Martins, RosárioCyanobacteria are widely recognized as a valuable source of bioactive metabolites. The majority of such compounds have been isolated from so-called complex cyanobacteria, such as filamentous or colonial forms, which usually display a larger number of biosynthetic gene clusters in their genomes, when compared to free-living unicellular forms. Nevertheless, picocyanobacteria are also known to have potential to produce bioactive natural products. Here, we report the isolation of hierridin B from the marine picocyanobacterium Cyanobium sp. LEGE 06113. This compound had previously been isolated from the filamentous epiphytic cyanobacterium Phormidium ectocarpi SAG 60.90, and had been shown to possess antiplasmodial activity. A phylogenetic analysis of the 16S rRNA gene from both strains confirmed that these cyanobacteria derive from different evolutionary lineages. We further investigated the biological activity of hierridin B, and tested its cytotoxicity towards a panel of human cancer cell lines; it showed selective cytotoxicity towards HT-29 colon adenocarcinoma cells.
- Are known cyanotoxins involved in the toxicity of picoplanktonic and filamentous north atlantic marine cyanobacteria?Publication . Frazão, Bárbara; Martins, Rosario; Vasconcelos, VítorEight marine cyanobacteria strains of the genera Cyanobium, Leptolyngbya, Oscillatoria, Phormidium, and Synechococcus were isolated from rocky beaches along the Atlantic Portuguese central coast and tested for ecotoxicity. Strains were identified by morphological characteristics and by the amplification and sequentiation of the 16S rDNA. Bioactivity of dichloromethane, methanol and aqueous extracts was assessed by the Artemia salina bioassay. Peptide toxin production was screened by matrix assisted laser desorption/ionization time of flight mass spectrometry. Molecular analysis of the genes involved in the production of known cyanotoxins such as microcystins, nodularins and cylindrospermopsin was also performed. Strains were toxic to the brine shrimp A. salina nauplii with aqueous extracts being more toxic than the organic ones. Although mass spectrometry analysis did not reveal the production of microcystins or other known toxic peptides, a positive result for the presence of mcyE gene was found in one Leptolyngbya strain and one Oscillatoria strain. The extensive brine shrimp mortality points to the involvement of other unknown toxins, and the presence of a fragment of genes involved in the cyanotoxin production highlight the potential risk of cyanobacteria occurrence on the Atlantic coast.
- Bibliometric analysis towards industrial-scale use of Marine Algae and Lichens as soil amendments and plant biofertilizers for sustainable agriculturePublication . Ouala, Oumaima; Essadki, Yasser; Oudra, Brahim; Khalloufi, Fatima El; Martins, Rosário; Martins, RosarioThe nutrient-rich composition of seaweeds and lichens makes them well-suited for agricultural applications. Their use as alternatives to synthetic fertilizers contributes to sustainable agricultural production, enabling farmers to adopt ecological practices while maintaining or increasing crop productivity. This review aims to highlight the status and trends of research, along with a literature analysis on the application of these biomasses in sustainable agriculture. A bibliometric analysis was performed based on two databases (Scopus and Web of Science) to overview the main research topics regarding the use of biomasses studied in agriculture, thus providing useful information for future research. The biochemical composition and agricultural applications of these biomasses have been highlighted. The analysis shows that these biomasses are rich of nutrient compounds, revealing their roles and mechanisms of action on the chemical, nutritional properties, and soil microbial activities and their effect on plant growth, using various extraction and application methods. It also highlighted the potential of seaweeds for protection against biotic and abiotic stresses. In light of all the data presented in this review, it is possible to stimulate farmers’ interest in using seaweeds and lichens as natural fertilizers, with a focus on sustainable and ecological agriculture mainly in developing countries.
- Bridging cyanobacteria to neurodegenerative diseases: a new potential source of bioactive compounds against Alzheimer’s diseasePublication . Castaneda, Andrea; Ferraz, Ricardo; Vieira, Mónica; Cardoso, Isabel; Vasconcelos, Vítor; Martins, RosárioNeurodegenerative diseases (NDs) represent a drawback in society given the ageing population. Dementias are the most prevalent NDs, with Alzheimer’s disease (AD) representing around 70% of all cases. The current pharmaceuticals for AD are symptomatic and with no effects on the progression of the disease. Thus, research on molecules with therapeutic relevance has become a major focus for the scientific community. Cyanobacteria are a group of photosynthetic prokaryotes rich in biomolecules with confirmed activity in pathologies such as cancer, and with feasible potential in NDs such as AD. In this review, we aimed to compile the research works focused in the anti-AD potential of cyanobacteria, namely regarding the inhibition of the enzyme β-secretase (BACE1) as a fundamental enzyme in the generation of β-amyloid (Aβ), the inhibition of the enzyme acetylcholinesterase (AChE) lead to an increase in the availability of the neurotransmitter acetylcholine in the synaptic cleft and the antioxidant and anti-inflammatory effects, as phenomena associated with neurodegeneration mechanisms.
- Carotenoids from cyanobacteria modulate iNOS and inhibit the production of inflammatory mediators: Promising agents for the treatment of inflammatory conditionsPublication . Morone, Janaína; Vasconcelos, Vitor; Hentschke, Guilherme; Rosário Martins, Maria; Pinto, Eugénia; Lopes, GracilianaCyanobacteria are green multiproduct refineries of increasing interest for different industrial prospects. In this work, eleven cyanobacteria strains isolated from the Cape Verde archipelago were explored for their biotechnological applications in the field of inflammation. A biorefinery approach was employed to produce carotenoidtargeted extracts, further profiled by HPLC-PDA and explored for their ability to i) scavenge important physiological free radicals of oxygen (superoxide anion radical, O 2 •) and nitrogen (nitric oxide, • NO) involved in the inflammatory process ii) slow-down post-inflammatory hyperpigmentation and iii) modulate the activity of inf lammatory cytokine-producing enzymes, in enzymatic and cell systems comprising RAW 264.7 cells. The studied strains turned out to be important carotenoid producers (70.47–186.71 μ g mg 1 dry extract), mainly represented by β-carotene and zeaxanthin. The targeted-extracts stood-out for their potential to slow-down the inflammatory process through a multitarget approach: scavenging • NOandO 2 •, reducing inflammatory cytokines production through lipoxygenase inhibition, and modulating the inducible nitric oxide synthase in LPSstimulated RAW 264.7 cells, with strains of the order Nodosilineales revealing to be worth of further biotechnological exploitation.
- Colouring applications of microalgae and cyanobacteria photosynthetic pigments: Challenges for industrial and market acceptancePublication . Reimão, Mariana; Almeida, Liliana; Ramos, Cristiana; Eusébio, Nádia; Martins, Rosário; Silva, Manuela Vieira da; Vasconcelos, Vítor; Freitas, Marisa; Freitas, Marisa; Vieira da Silva, Manuela; Martins, Rosario; REIMÃO BORGES LOPES DA SILVA, MARIANAMicroalgae and cyanobacterial photosynthetic pigments possess immense potential for sustainable colouring applications in industries such as food, feed, cosmetics and textiles, primarily because of their vibrant colours, safety and eco-friendliness. These photosynthetic pigments align with the growing demand for eco-conscious products. However, substantial challenges persist at the industrial level, particularly in scaling up production and achieving acceptance in niche markets. This review highlights the critical roles of abiotic factors such as light quality, temperature, pH, nutrient availability and salinity in enhancing pigment production using conventional production methods. Additionally, issues related to the cost, purity and stability of the pigments must be addressed to facilitate broader acceptance. Looking forward, the focus must be on developing innovative cultivation techniques that optimise and define the abiotic conditions most favourable for maximum pigment production or even incorporate genetic engineering tools. Additionally, exploring untapped species from inhospitable environmental sources and integrating the residual biomass through biorefinery processes represent effective approaches for enhancing the sustainability of microalgae and cyanobacterial pigment production on an industrial scale. Overcoming these barriers utilising targeted research and industry collaboration as well as fostering market acceptance is essential for fully harnessing the potential of these natural pigments and driving the transition towards more sustainable industrial colouring practices.
- Cosmetic application of cyanobacteria extracts with a sustainable vision to skincare: role in the antioxidant and antiaging processPublication . Morone, Janaína; Lopes, Graciliana; Morais, João; Neves, Jorge; Vasconcelos, Vítor; Martins, RosárioNature-based and sustainably sourced cosmetics have been dominating the area of skincare products worldwide. Due to their antioxidant and antiaging properties, compounds from cyanobacteria, such as carotenoids and phycobiliproteins, may replace synthetic ingredients in cosmetic formulations and may be used in products such as sunscreens, skincare creams, and makeup. In this study, we evaluated the potential of acetonic and aqueous extracts from cyanobacteria strains of the genera Cyanobium and Leptothoe and from strains within Synechococcales and Oscillatori ales orders, for use in cosmetics. Extractions were sequentially performed with acetone and water. Extracts were firstly analyzed for their toxicity to keratinocytes, fibroblasts, and endothelial cells (HaCAT, 3T3L1 and hCMEC/D3, respectively). The non-cytotoxic extracts were characterized in terms of total proteins, carotenoids, chlorophyll, phenols, phycobiliproteins, and analyzed for their antioxidant potential against the superoxide anion radical (O2 •−), and for their ability to inhibit key enzymes associated with the skin aging process. Aqueous extracts were richer in total proteins and phycobiliproteins. The aqueous extracts of Synechococcales cyanobacterium LEGE 181157 and Synechococcales cyanobacterium LEGE 181150 showed the highest value for total proteins (760.81 and 695.25 µg BSA mL−1 dry extract, respectively) and the best values regarding O2 •− scavenging (IC50 = 63.24 and 112.18 µg mL−1 dry extract, respectively) with a significant negative correlation ob served (p < 0.01). Moreover, aqueous extracts of Synechococcales cyanobacterium LEGE 181150 and Synechococcales cyanobacterium LEGE 181157 inhibited hyaluronidase, (IC50 of 483.86 and 645.06 µg mL−1 dry extract, respectively), with a significant negative correlation with total proteins (p < 0.05), pointing out the contribution of these compounds to the biological activities observed. Acetonic extracts were richer in carotenoids and phenols. Zeaxanthin and β-carotene were pre dominant among all strains, being present in higher amount in Cyanobium sp. LEGE 07175 (53.08 µg mg−1 ) and Leptothoe sp. LEGE 181156 (47.89 µg mg−1 ), respectively. The same strains also showed the highest values for collagenase inhibition at 750 µg mL−1 dry extract (32.88 and 36.61%, respectively). Furthermore, Leptothoe sp. LEGE 181156 exhibited the lowest IC50 value for tyrosinase inhibition (465.92 µg mL−1 dry extract) and Synechococcales cyanobacterium LEGE 181157 presented the best values for elastase inhibition (IC50 of 380.50 and IC25 of 51.43 µg mL−1 dry extract). In general, cyanobacteria extracts demonstrated potential for being used for antiaging purposes, with aqueous extracts being more efficient at free radicals scavenging and acetonic ones at avoiding degradation of dermal matrix components.
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