RESUMO
Microalgae are a source of a wide variety of commodities, including particularly valuable pigments. The typical pigments present in microalgae are the chlorophylls, carotenoids, and phycobiliproteins. However, other types of pigments, of the family of water-soluble polyphenols, usually encountered in terrestrial plants, have been recently reported in microalgae. Among such microalgal polyphenols, many flavonoids have a yellowish hue, and are used as natural textile dyes. Besides being used as natural colorants, for example in the food or cosmetic industry, microalgal pigments also possess many bioactive properties, making them functional as nutraceutical or pharmaceutical agents. Each type of pigment, with its own chemical structure, fulfills particular biological functions. Considering both eukaryotes and prokaryotes, some species within the four most promising microalgae groups (Cyanobacteria, Rhodophyta, Chlorophyta and Heterokontophyta) are distinguished by their high contents of specific added-value pigments. To further enhance microalgae pigment contents during autotrophic cultivation, a review is made of the main related strategies adopted during the last decade, including light adjustments (quantity and quality, and the duration of the photoperiod cycle), and regard to mineral medium characteristics (salinity, nutrients concentrations, presence of inductive chemicals). In contrast to what is usually observed for growth-related pigments, accumulation of non-photosynthetic pigments (polyphenols and secondary carotenoids) requires particularly stressful conditions. Finally, pigment enrichment is also made possible with two new cutting-edge technologies, via the application of metallic nanoparticles or magnetic fields.
Assuntos
Microalgas , Pigmentos Biológicos , Microalgas/metabolismo , Microalgas/química , Pigmentos Biológicos/química , Carotenoides/química , Carotenoides/metabolismo , Carotenoides/análise , Ficobiliproteínas/química , Ficobiliproteínas/metabolismo , Cianobactérias/metabolismo , Cianobactérias/química , Rodófitas/química , Rodófitas/metabolismo , Clorófitas/química , Clorófitas/metabolismo , Clorofila/análise , Polifenóis/análise , Polifenóis/química , Polifenóis/metabolismo , Meios de Cultura/químicaRESUMO
The mass proliferation of cyanobacteria, episodes known as blooms, is a concern worldwide. One of the most critical aspects during these blooms is the production of toxic secondary metabolites that are not limited to the four cyanotoxins recognized by the World Health Organization. These metabolites comprise a wide range of structurally diverse compounds that possess bioactive functions. Potential human and ecosystem health risks posed by these metabolites and co-produced mixtures remain largely unknown. We studied acute lethal and sublethal effects measured as impaired mobility on the freshwater microcrustaceans Thamnocephalus platyurus for metabolite mixtures from two cyanobacterial strains, a microcystin (MC) producer and a non-MC producer. Both cyanobacterial extracts, from the MC-producer and non-MC-producer, caused acute toxicity with LC50 (24 h) values of 0.50 and 2.55 mgdw_biomass/mL, respectively, and decreased locomotor activity. Evaluating the contribution of different cyanopeptides revealed that the Micropeptin-K139-dominated fraction from the MC-producer extract contributed significantly to mortality and locomotor impairment of the microcrustaceans, with potential mixture effect with other cyanopeptolins present in this fraction. In the non-MC-producer extract, compounds present in the apolar fraction contributed mainly to mortality, locomotor impairment, and morphological changes in the antennae of the microcrustacean. No lethal or sublethal effects were observed in the fractions dominated by other cyanopetides (Cyanopeptolin 959, Nostoginin BN741). Our findings contribute to the growing body of research indicating that cyanobacterial metabolites beyond traditional cyanotoxins cause detrimental effects. This underscores the importance of toxicological assessments of such compounds, also at sublethal levels.
Assuntos
Cianobactérias , Microcistinas , Poluentes Químicos da Água , Microcistinas/toxicidade , Animais , Cianobactérias/química , Poluentes Químicos da Água/toxicidade , Água Doce/química , Comportamento Animal/efeitos dos fármacos , Anostraca/efeitos dos fármacos , Dose Letal MedianaRESUMO
Jamaicamide B was isolated from the cyanobacterium Moorea producens in Jamaica and shows neurotoxicity. This unique mixed peptide-polyketide structure contains a pyrrolinone ring, a ß-methoxy enone, an (E)-olefin, an undetermined stereocenter at C9, an (E)-chloroolefin, and a terminal alkyne. We report herein the first total synthesis and structural confirmation of the marine natural product (9R)-jamaicamide B.
Assuntos
Cianobactérias , Cianobactérias/química , Produtos Biológicos/síntese química , Produtos Biológicos/química , Estereoisomerismo , Estrutura MolecularRESUMO
Cyanobacterial blooms affect aquatic ecosystems across the globe and one major concern relates to their toxins such as microcystins (MC). Yet, the ecotoxicological risks, particularly non-lethal effects, associated with other co-produced secondary metabolites remain mostly unknown. Here, we assessed survival, morphological alterations, swimming behaviour and cardiovascular functions of zebrafish (Danio rerio) upon exposure to cyanobacterial extracts of two Brazilian Microcystis strains. We verified that only MIRS-04 produced MCs and identified other co-produced cyanopeptides also for the MC non-producer NPCD-01 by LC-HRMS/MS analysis. Both cyanobacterial extracts, from the MC-producer and non-producer, caused acute toxicity in zebrafish with LC50 values of 0.49 and 0.98 mgdw_biomass/mL, respectively. After exposure to MC-producer extract, additional decreased locomotor activity was observed. The cyanopeptolin (micropeptin K139) contributed 52% of the overall mortality and caused oedemas of the pericardial region. Oedemas of the pericardial area and prevented hatching were also observed upon exposure to the fraction with high abundance of a microginin (Nostoginin BN741) in the extract of the MC non-producer. Our results further add to the yet sparse understanding of lethal and sublethal effects caused by cyanobacterial metabolites other than MCs and the need to better understand the underlying mechanisms of the toxicity. We emphasize the importance of considering mixture toxicity of co-produced metabolites in the ecotoxicological risk assessment of cyanobacterial bloom events, given the importance for predicting adverse outcomes in fish and other organisms.
Assuntos
Cianobactérias , Microcystis , Poluentes Químicos da Água , Animais , Microcistinas/toxicidade , Microcistinas/metabolismo , Peixe-Zebra , Ecossistema , Larva , Poluentes Químicos da Água/toxicidade , Cianobactérias/química , Microcystis/metabolismoRESUMO
Cyanobacteria are a rich source of secondary metabolites, and they have received a great deal of attention due to their applicability in different industrial sectors. Some of these substances are known for their notorious ability to inhibit fungal growth. Such metabolites are very chemically and biologically diverse. They can belong to different chemical classes, including peptides, fatty acids, alkaloids, polyketides, and macrolides. Moreover, they can also target different cell components. Filamentous cyanobacteria have been the main source of these compounds. This review aims to identify the key features of these antifungal agents, as well as the sources from which they are obtained, their major targets, and the environmental factors involved when they are being produced. For the preparation of this work, a total of 642 documents dating from 1980 to 2022 were consulted, including patents, original research, review articles, and theses.
Assuntos
Antifúngicos , Cianobactérias , Antifúngicos/química , Cianobactérias/química , Antibacterianos/farmacologia , Macrolídeos/metabolismoRESUMO
BACKGROUND: Cyanobacteria are prokaryotic organisms with wide morphological and metabolic diversity. By means of photosynthesis, they convert inorganic compounds into biomolecules, which may have commercial interest. In this work, we evaluated 20 cyanobacterial strains regarding their physiological aspects such as growth, photosynthesis and biochemical composition, some of which are revealed here for the first time. The organisms were cultivated in cylindrical photobioreactors (CPBR) for 144 h and the biomass was obtained. The light inside cultures was constant throughout experimental time and maintained at the saturation irradiance (Ik) of each species. Culture pH was maintained within 7.8 and 8.4 by automatic CO2 bubbling. Growth rate, dry biomass, chlorophyll a, carotenoids, phycocyanin, proteins, carbohydrates, lipids, polyhydroxyalkanoate (PHA) and antioxidant activity were determined. RESULTS: The proportionality of the biochemical composition varied among species, as well as the growth rates. Leptolyngbya sp. and Nostoc sp. (CCIBt3249) showed growth rates in the range of 0.7-0.8 d-1, followed by Rhabdorderma sp. (~ 0.6 d-1), and Phormidium sp. (~ 0.5 d-1). High carotenoid content was obtained in Rhabdoderma sp. (4.0 µg mL-1) and phycocyanin in Leptolyngbya sp. (60 µg mL-1). Higher total proteins were found in the genus Geitlerinema (75% DW), carbohydrates in Microcystis navacekii (30% DW) and lipids in Phormidium sp. (15% DW). Furthermore, Aphanocapsa holsatica showed the highest antioxidant activity (65%) and Sphaerocavum brasiliense, Microcystis aeruginosa, Nostoc sp. (CCIBt3249) and A. holsatica higher levels of PHA (~ 2% DW). CONCLUSIONS: This study reports on the biochemical composition of cyanobacteria that can impact the biotechnology of their production, highlighting potential strains with high productivity of specific biomolecules.
Assuntos
Antioxidantes , Cianobactérias , Fotobiorreatores , Antioxidantes/metabolismo , Biomassa , Carboidratos , Carotenoides/metabolismo , Clorofila A , Lipídeos , Nostoc/metabolismo , Ficocianina , Cianobactérias/química , Cianobactérias/crescimento & desenvolvimento , Cianobactérias/metabolismoRESUMO
The marine environment is highly diverse, each living creature fighting to establish and proliferate. Among marine organisms, cyanobacteria are astounding secondary metabolite producers representing a wonderful source of biologically active molecules aimed to communicate, defend from predators, or compete. Studies on these molecules' origins and activities have been systematic, although much is still to be discovered. Their broad chemical diversity results from integrating peptide and polyketide synthetases and synthases, along with cascades of biosynthetic transformations resulting in new chemical structures. Cyanobacteria are glycolipid, macrolide, peptide, and polyketide producers, and to date, hundreds of these molecules have been isolated and tested. Many of these compounds have demonstrated important bioactivities such as cytotoxicity, antineoplastic, and antiproliferative activity with potential pharmacological uses. Some are currently under clinical investigation. Additionally, conventional chemotherapeutic treatments include drugs with a well-known range of side effects, making anticancer drug research from new sources, such as marine cyanobacteria, necessary. This review is focused on the anticancer bioactivities of metabolites produced by marine cyanobacteria, emphasizing the identification of each variant of the metabolite family, their chemical structures, and the mechanisms of action underlying their biological and pharmacological activities.
Assuntos
Antineoplásicos , Produtos Biológicos , Cianobactérias , Antineoplásicos/química , Organismos Aquáticos/química , Produtos Biológicos/química , Cianobactérias/química , Chumbo/metabolismo , Macrolídeos/metabolismo , Peptídeos/químicaRESUMO
Anthropogenic pollution and global climate change have resulted in favorable environmental conditions for increased frequency and duration of cyanobacterial blooms in aquatic systems. Cyanobacteria can produce toxic metabolites called cyanotoxins, which have become a worldwide concern as they threaten human and animal health. The presence of cyanobacteria and four cyanotoxins were evaluated in a Colombian reservoir. The reservoir was monitored for a year, with sampling campaigns every 3 months in seven stations. To identify and quantify cyanotoxins, the ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-QqQ-MS/MS) technique was used, and the quantification of cyanobacteria was done by quantitative real-time PCR (qPCR) assay using a cyanobacterial-specific 16S rRNA gene fragment as a target. Cyanobacteria concentration was between 4.02 (± 0.11) × 104 and 2.72 (± 0.28) × 107 copies of Cyan 16S/µL, the minimum value corresponds to the station located in the central zone and the maximum to the station at the entrance of one of the tributary rivers. The presence of MC-RR, MC-LR, MC-YR, and NOD was detected in at least six of the seven sampling stations at different times of the year. In all cases, the concentration of the toxins detected was below 0.05 µg/L, so the guideline value established by the WHO for MC-LR was not exceeded.
Assuntos
Cianobactérias , Microcistinas , Animais , Colômbia , Cianobactérias/química , Toxinas de Cianobactérias , Humanos , Microcistinas/análise , RNA Ribossômico 16S , Espectrometria de Massas em Tandem/métodosRESUMO
Three new compounds, portobelamides A and B (1 and 2), 3-amino-2-methyl-7-octynoic acid (AMOYA) and hydroxyisovaleric acid (Hiva) containing cyclic depsipeptides, and one long chain lipopeptide caciqueamide (3), were isolated from a field-collection of a Caldora sp. marine cyanobacterium obtained from Panama as part of the Panama International Cooperative Biodiversity Group Program. Their planar structures were elucidated through analysis of 2D NMR and MS data, especially high resolution (HR) MS2/MS3 fragmentation methods. The absolute configurations of compounds 1 and 2 were deduced by traditional hydrolysis, derivative formation, and chromatographic analyses compared with standards. Portobelamide A (1) showed good cytotoxicity against H-460 human lung cancer cells (33% survival at 0.9 µM).
Assuntos
Antineoplásicos/farmacologia , Cianobactérias/química , Depsipeptídeos/química , Antineoplásicos/química , Organismos Aquáticos/química , Produtos Biológicos/química , Produtos Biológicos/farmacologia , Linhagem Celular Tumoral , Depsipeptídeos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , PanamáRESUMO
Cyanobacteria are a rich source of secondary metabolites with a vast biotechnological potential. These compounds have intrigued the scientific community due their uniqueness and diversity, which is guaranteed by a rich enzymatic apparatus. The ribosomally synthesized and post-translationally modified peptides (RiPPs) are among the most promising metabolite groups derived from cyanobacteria. They are interested in numerous biological and ecological processes, many of which are entirely unknown. Microviridins are among the most recognized class of ribosomal peptides formed by cyanobacteria. These oligopeptides are potent inhibitors of protease; thus, they can be used for drug development and the control of mosquitoes. They also play a key ecological role in the defense of cyanobacteria against microcrustaceans. The purpose of this review is to systematically identify the key characteristics of microviridins, including its chemical structure and biosynthesis, as well as its biotechnological and ecological significance.