Search Results (63)

Conventional methods for extracting bioactive compounds from microalgae rely on organic solvents that are both polluting and potentially harmful to human health. In recent years, a noticeable shift has emerged toward greener extraction alternatives that are more environmentally friendly and sustainable. This review highlights various green extraction techniques, compounds, and yields obtained from different microalgal species for a range of applications and provides a comparison between the yields of conventional and green extraction methods. Green extraction methods have shown yields that are comparable to, or even exceed, those of conventional techniques, although they are predominantly studied for the extraction of lipids and pigments. This review aims to provide an overview of the current state of green extraction applied to microalgae, and to outline future research perspectives in this emerging field. Full article

Anthozoa is a species-rich class with an innate immune system that acts as a defensive tool and shares many of its cellular pathways with mammalian immune responses. In addition to immune-related strategies (e.g., allorecognition and xenorecognition), anthozoans have evolved to use compounds or toxins for chemical communication, defense, or predation, which may exhibit biological activities useful for human health, mainly antiviral, antibacterial, anti-inflammatory, anticancer, and antitumor properties of pharmaceutical interest. These compounds/toxins can be alkaloids, amino acids, proteins, ceramides, diterpenes, and sesquiterpenes and are mainly distributed into Hexacorallia and Octocorallia. Anthozoans are enriched in defensive enzymes, which can either be found in anthozoan species or their symbionts and help them survive in hostile conditions. Studies related to genomics and transcriptomics using advanced sequencing efforts revealed the presence of genetic elements in anthozoans that help them survive against abiotic and biotic stressors in the marine environment. This review presents developments and highlights the current state of knowledge about anthozoans’ chemical weaponry that can drive further bioprospection of anthozoan species producing compounds and toxins which may be useful in biotechnological applications. Omics research in Anthozoa is still nascent, and more efforts are required to fully understand the chemical ecology, diversity, and possible biotechnological applications of cnidarian genes and their products. Full article

Cnidarian defensive strategies are commonly associated with the toxins they synthesize. Because toxins have negative, sometimes lethal, effects on humans, research has focused on them for medical and biotechnological applications. However, Cnidaria possess a variety of defensive systems complementing toxins. In recent decades, ecological and biotechnological studies have shed light on these systems, particularly in Anthozoa, while the knowledge of defensive systems different from toxins has remained limited in Medusozoa (Cubozoa, Hydrozoa, Scyphozoa and Staurozoa). In this review, we collected the scattered information available in the literature and organized it into four main topics: UV-light protection compounds, antioxidants, antimicrobial peptides, and endosymbionts. Within the topics, we found the largest amount of data refers to antimicrobial activities, which suggests this line of research as a potential exploitation of this group of organisms often appearing in large aggregates. We also found that some Medusozoa have been studied in detail as model organisms, although the close phylogenetic relationship among classes suggests that some defensive strategies may be common to other members of different classes. Indeed, an integrated understanding of defensive systems has the potential to inform not only ecological and evolutionary frameworks, but also biotechnological applications—from the identification of novel antioxidants or antimicrobial agents to the valorization of Medusozoan biomass. Full article

Highly conserved among eukaryotes, the chemical defensome protects organisms against chemical stressors and helps to reestablish the altered homeostatic state. The defensome includes genes such as transporters (e.g., adenosine triphosphate ATP-binding cassette), phase I and phase II detoxification enzymes, and antioxidant enzymes. During their life cycle, planktonic copepods, the most abundant and ubiquitous metazoans on Earth, are exposed to many environmental stressors that impair their survival and fitness. Here, using high-quality publicly available transcriptomic data, defensome genes were searched in copepods belonging to different orders and living in different environments (e.g., Antarctic, Subarctic, Mediterranean). Gene expression responses were investigated in four calanoids exposed to different stresses to identify a common and species-specific detoxification system. Our results confirm that the defensome is highly conserved among copepods but also report differences in the relative contribution of genes among species living in different habitats, suggesting a fitness adaptation to environmental pressures. The genes provided here can be used as biomarkers of chemical defense and can also be tested in other planktonic organisms to assess the “health” of marine organisms, which is useful for understanding environmental adaptations and they can be used to assess changes and make predictions at the population and community levels. Full article

There are still several viral infections affecting a considerable number of the world’s population, causing thousands of deaths each year. There are no drugs available for most viral infections and for many not even a vaccine. The marine kingdom is characterized by a huge chemical diversity; however, there is currently on the market only one drug derived from the sea with antiviral properties, called Ara-A. In the current study, we used a solid phase extraction method (SPE) to obtain pre-purified fractions from Diacronema lutheri raw extracts. We tested both raw extracts and fractions against enveloped and non-enveloped viruses. Results showed an antiviral activity of fraction C of D. lutheri against the herpes simplex virus type 1 (HSV-1 strain SC16). Liquid chromatography coupled with untargeted high-resolution tandem mass spectrometry (LC-HRMS²) were employed to chart the metabolite distribution in all SPE fractions and pinpoint molecular families unique (or almost unique) to the bioactive fraction. Sulfoquinovosyl di- and monoacylglycerols (SQDGs and SQMGs) and di- and monogalactosyl monoacylglycerols (DGMGs and MGMGs) represent the largest groups of compounds in fraction C and they are likely responsible for the antiviral properties of this fraction. Full article

Climate changes may include variations in salinity concentrations at sea by changing ocean dynamics. These variations may be especially challenging for marine photosynthetic organisms, affecting their growth and distribution. Chlamydomonas spp. are ubiquitous and are often found in extreme salinity conditions. For this reason, they are considered good model species to study salinity adaptation strategies. In the current study, we used an integrated approach to study the Chlamydomonas sp. CCMP225 response to salinities of 20‰ and 70‰, by combining physiological, morphological, and transcriptomic analyses, and comparing differentially expressed genes in the exponential and stationary growth phases under the two salinity conditions. The results showed that the strain is able to grow under all tested salinity conditions and maintains a surprisingly high photosynthetic efficiency even under high salinities. However, at the highest salinity condition, the cells lose their flagella. The transcriptomic analysis highlighted the up- or down-regulation of specific gene categories, helping to identify key genes responding to salinity stress. Overall, the findings may be of interest to the marine biology, ecology, and biotechnology communities, to better understand species adaptation mechanisms under possible global change scenarios and the potential activation of enzymes involved in the synthesis of bioactive molecules. Full article

Epitranscriptomics is considered as a new regulatory step in eukaryotes for developmental processes and stress responses. The aim of this study was, for the first time, to identify RNA methyltransferase (writers) and demethylase (erasers) in four investigated species, i.e., the dinoflagellates Alexandrium tamutum and Amphidinium carterae, the diatom Cylindrotheca closterium, and the green alga Tetraselmis suecica. As query sequences for the enzymatic classes of interest, we selected those ones that were previously detected in marine plants, evaluating their expression upon nutrient starvation stress exposure. The hypothesis was that upon stress exposure, the activation/deactivation of specific writers and erasers may occur. In microalgae, we found almost all plant writers and erasers (ALKBH9B, ALKBH10B, MTB, and FIP37), except for three writers (MTA, VIRILIZER, and HAKAI). A sequence similarity search by scanning the corresponding genomes confirmed their presence. Thus, we concluded that the three writer sequences were lacking from the studied transcriptomes probably because they were not expressed in those experimental conditions, rather than a real lack of these genes from their genomes. This study showed that some of them were expressed only in specific culturing conditions. We also investigated their expression in other culturing conditions (i.e., nitrogen depletion, phosphate depletion, and Zinc addition at two different concentrations) in A. carterae, giving new insights into their possible roles in regulating gene expression upon stress. Full article

Heart disease is one of the leading causes of death worldwide, and it is estimated that 17.9 million people die of it each year. The risk factors for cardiovascular diseases are attributable to an unhealthy and sedentary lifestyle, poor nutrition, stress, genetic predisposition, diabetes, obesity, and aging. Marine microalgae have been the subject of numerous studies for their potential activity against several human diseases. They produce a plethora of primary and secondary metabolites such as essential nutrients, vitamins, pigments, and omega-3 fatty acid. Many of these molecules have antioxidant properties and have been shown to play a role in the prevention of heart diseases. The aim of this review is to summarize recent studies on the discovery of marine microalgal compounds and bioactivities for cardiovascular diseases, including in vitro and in vivo studies, showing and discussing recent discoveries and trends. The most promising results were found for microalgal polysaccharides, peptides and carotenoids. In conclusion, the overall data summarized here show that microalgae-based supplementation has the potential to improve age-related cardiovascular diseases and we expect more clinical studies in the future. Full article

Folate, also known as vitamin B9, plays a crucial role in the one-carbon (1C) metabolism, a conserved pathway from microbes to humans. The 1C metabolism, consisting of the folate and methionine cycles, is essential in many biological processes such as nucleotide and protein biosynthesis, cell proliferation, and embryonic development. Despite its functional role, little is known about the 1C metabolism in crustaceans. As part of an ongoing effort to characterize important pathways in Calanus finmarchicus, the biomass-dominant zooplankton in much of the North Atlantic Ocean, we identified transcripts encoding the 1C metabolism enzymes. Using an in silico workflow consisting of a transcriptome mining, reciprocal blasts, and structural analyses of the deduced proteins, we identified the entire set of enzymes in both cycles. The majority encoded for full-length proteins and clustered with homologs from other species. Stage-specific expression was reported, with several transcripts showing high expression in the naupliar stage (e.g., 10-FTHFD, SHMT2) while some methyltransferases (e.g., BHMT, SHMT, DNMT) were more expressed in adults. Overall, this study provides a set of genes which can be used as potential biomarkers of development and reproduction and can be tested in other zooplankters to assess ocean health status monitoring. Full article

Microalgae have been reported to be excellent producers of bioactive molecules. Lutein is a pigment reported to have various beneficial effects for humans, and especially for eye well-being. In the current review, we summarize various methods that have been developed to optimize its extraction and bioactivities reported for human health. Several protective effects have been reported for lutein, including antioxidant, anticancer, anti-inflammatory, and cardioprotective activity. This review also reports attempts to increase lutein production by microalgae by changing culturing parameters or by using pilot-scale systems. Genetic engineering lutein production is also discussed. Considering the increasing aging of the worldwide population will create an increased need for lutein, a viable economic and eco-sustainable method to produce lutein is needed to face this market demand. Full article

Many dinoflagellates of the genus Alexandrium are well known for being responsible for harmful algal blooms (HABs), producing potent toxins that cause damages to other marine organisms, aquaculture, fishery, tourism, as well as induce human intoxications and even death after consumption of contaminated shellfish or fish. In this review, we summarize potential bioprospecting associated to the genus Alexandrium, including which Alexandrium spp. produce metabolites with anticancer, antimicrobial, antiviral, as well as anti-Alzheimer applications. When available, we report their mechanisms of action and targets. We also discuss recent progress on the identification of secondary metabolites with biological properties favorable to human health and aquaculture. Altogether, this information highlights the importance of studying which culturing conditions induce the activation of enzymatic pathways responsible for the synthesis of bioactive metabolites. It also suggests considering and comparing clones collected in different locations for toxin monitoring and marine bioprospecting. This review can be of interest not only for the scientific community, but also for the entire population and industries. Full article

Marine organisms have developed a series of defense and adaptation strategies, permitting them to live and survive in peculiar environments, ranging from temperate to tropical and polar regions, high to low salinity areas and different light conditions, as well as are constantly exposed to variations induced by climate change and human activities. These defense strategies include the production of molecules and enzymes which may have applications for humans as well. In this review, we summarized the studies on bacterial and microalgal polyunsaturated fatty acids, antioxidants, and antifreeze proteins, which can find applications in different market sectors, such as feed and cosmetic fields. For all the aforementioned compounds, the compound annual growth rate is expected to increase by 5.35–36.3% in the near future, as the market interest toward these products is on the rise. Both industries and researchers are focused on developing mechanisms to reduce production time and costs, improve yields, and discover new proteins. Full article

Chemical interactions have been shown to regulate several marine life processes, including selection of food sources, defense, behavior, predation, and mate recognition. These chemical communication signals have effects not only at the individual scale, but also at population and community levels. This review focuses on chemical interactions between marine fungi and microalgae, summarizing studies on compounds synthetized when they are cultured together. In the current study, we also highlight possible biotechnological outcomes of the synthetized metabolites, mainly for human health applications. In addition, we discuss applications for bio-flocculation and bioremediation. Finally, we point out the necessity of further investigating microalgae-fungi chemical interactions because it is a field still less explored compared to microalga–bacteria communication and, considering the promising results obtained until now, it is worthy of further research for scientific advancement in both ecology and biotechnology fields. Full article

Cold environments include deep ocean, alpine, and polar areas. Even if the cold conditions are harsh and extreme for certain habitats, various species have been adapted to survive in them. Microalgae are among the most abundant microbial communities which have adapted to live in low light, low temperature, and ice coverage conditions typical of cold environments by activating different stress-responsive strategies. These species have been shown to have bioactivities with possible exploitation capabilities for human applications. Even if they are less explored compared to species living in more accessible sites, various activities have been highlighted, such as antioxidant and anticancer activities. This review is focused on summarizing these bioactivities and discussing the possible exploitation of cold-adapted microalgae. Thanks to the possibility of mass cultivating algae in controlled photobioreactors, eco-sustainable exploitation is in fact possible by sampling a few microalgal cells without impacting the environment. Full article