Search Results (19)

Background/Objectives: Seagrasses are marine angiosperms capable of completing their life cycle in water; they have been used as food source and biomass for producing fertilizer, but their potential nutritional and health-promoting properties have been largely overlooked. Cymodocea nodosa (Ucria) Ascherson (family Cymodoceaceae) is emerging as one of the most interesting seagrass species due to its content in health promoting substances. Methods: In this review article, a revision of the literature on phytochemical constituents and the main potential therapeutic uses of C. nodosa was carried out. Results: Despite the growing interest in C. nodosa for its key ecological role and for being a potential source of bioactive compounds, comprehensive chemical studies about its composition are still limited. Compounds reported as C. nodosa constituents include fatty acids, phytosterols, polysaccharides, phenolic acids, hydroxycinnamic acids, flavonoid glycosides, terpenoids, and diarylheptanoids. As concerns potential therapeutic uses, C. nodosa extract, both polyphenolic and polysaccharidic, might be useful for the management of metabolic disorders, which is currently the most documented in addition to the antioxidant action. Conclusions: Cymodocea nodosa emerges as one of the most promising seagrass species as a source of bioactive compounds and for its potential in maintaining health status. Full article

The diffusive availability of CO₂ for photosynthesis is orders of magnitude lower in water than in air. This, and the low affinity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) for CO₂, implies that most marine photoautotrophs (cyanobacteria, microalgae, macroalgae and marine angiosperms or seagrasses) would be severely restricted were they to rely only on dissolved CO₂ for their photosynthetic performance. On the other hand, the ~120 times higher concentration of bicarbonate (HCO₃⁻) makes this inorganic carbon (Ci) form more available for utilisation by marine photosynthesisers. The most common way in marine macrophytes to utilise HCO₃⁻ is to convert it to CO₂ within acidic micro-zones of diffusion boundary layers (DBLs), including the cell walls, as catalysed by an outwardly acting carbonic anhydrase (CA). This would then generate an intra-chloroplastic (or for cyanobacteria intra-carboxysomal) CO₂-concentrating mechanism (CCM). Some algae (e.g., the common macroalgae Ulva spp.) and most cyanobacteria and microalgae feature direct HCO₃⁻ uptake as the most efficient CCM, while others (e.g., some red algae growing under low-light conditions) may rely on CO₂ diffusion only. We will in this contribution summarise our current understanding of photosynthetic carbon assimilation of submerged marine photoautotrophs, and in particular how their ‘biophysical’ CCMs differ from the ‘biochemical’ CCMs of terrestrial C₄ and Crassulacean Acid Metabolism (CAM) plants (for which there is very limited evidence in cyanobacteria, algae and seagrasses). Full article

The shedding of leaves by Posidonia oceanica (P. oceanica) in autumn results in the accumulation of shoreline debris, contributing to significant economic, social, and environmental problems. Due to the lack of alternative solutions, this waste biomass is disposed of in landfills, incurring an economic cost for the disposal process. In the context of the circular economy, anaerobic digestion (AD) can serve as a highly efficient biological alternative for treating and valorizing wastes with a high organic load. The aim of this research was to comparatively evaluate the performance and kinetics of the AD of ashore P. oceanica biomass and its anaerobic co-digestion (co-AD) with different nitrogen-rich co-substrates. To evaluate the effect of the nitrogen source in the co-AD system, peptone, casein, synthetic casein, urea, and the microalgae Raphidocelis subcapitata were used as co-substrates in biomethanization tests at a mesophilic temperature (35 ± 2 °C). The lowest methane yield was achieved for the sole AD of P. oceanica (79 ± 3 NL CH₄ kg⁻¹ VS), while the highest yields were found for the three co-ADs of P. oceanica with proteins (i.e., peptone, casein, and synthetic casein), showing no significant differences among them (380 ± 30 − 420 ± 30 NL CH₄ kg⁻¹ VS). Additionally, the first-order kinetics and the transference function model were proven and allowed for adequately fitting the experimental results of methane production with time. Full article

The Lake Faro brackish basin (Sicily, Italy) was established as a Global Geosite as a key locality of tectonic coastal lakes, but little research has been devoted to this rare geological and ecological framework. To fill this gap, the main stratigraphical, sedimentological, ecological, morpho-bathymetric, and structural features were reported, linking geodiversity with biodiversity. In Lake Faro, a shallow platform develops alongside a deep funnel-shaped basin, reaching a maximum depth of 29 m. A NNW-SSE trending steep cliff, representing the abrupt transition from the platform to the basin, was interpreted as a dextral transtensional fault (Lake Faro Fault), presumably active since the middle-late(?) Pleistocene. The switches of the steep cliff NW-wards, acquiring an E-W trend, was interpreted as being due to the occurrence of the normal Mortelle Fault, cut by the Faro Lake Fault. Bottom terrigenous deposits consisted of coarse- to fine-grained quartzo-lithic rich sediments deriving from high-grade metamorphic and igneous rocks, whereas bioclasts mainly derived from clam farming actives for several centuries up until today. The Quaternary shallow platform, from top to base, includes the following: (i) soft cover composed of coarse terrigenous and prevalent bioclastic deposits; (ii) hard conglomerates cemented by carbonates; and (iii) siliciclastic coarse deposits of the Messina Fm. In the deep basin, siliciclastic silty loams with minor amounts of bioclastic deposits prevailed in the soft cover. Substrate heterogeneity coupled with brackish-marine gradients are the main factors responsible for an articulate patchiness of different lagoon habitats and related benthic associations, which, according to the Barcelona Convention classification, can be summarized as follows: (i) MB1.541 (marine angiosperms or other halophytes), (ii) MB1.542 (Fucales), (iii) MB5.543 (photophilic algae, except Fucales), (iv) MB5.544 (Facies with Polychaeta), and (v) MB5.545 (Facies with Bivalvia). Typical marine associations, such as rhodolite beds, also occur. Finally, the lake, which has been exploited since the prehistoric age because of its high biodiversity and productivity, maintains some evidence of millennial relationships with the resident human cultures, attracted there by the favorable geomorphological and ecological peculiarities. Full article

Seagrass meadows consist of angiosperms that thrive fully submerged in marine environments and form distinct ecosystems. They provide essential support for many organisms, acting as nursery grounds for species of economic importance. Beyond their ecological roles, seagrasses and their associated microbiomes are rich sources of bioactive compounds with the potential to address numerous human healthcare challenges. Seagrasses produce bioactive molecules responding to physical, chemical, and biological environmental changes. These activities can treat microbe-borne diseases, skin diseases, diabetes, muscle pain, helminthic diseases, and wounds. Seagrasses also offer potential secondary metabolites that can be used for societal benefits. Despite numerous results on their presence and bioactive derivatives, only a few studies have explored the functional and therapeutic properties of secondary metabolites from seagrass. With the increasing spread of epidemics and pandemics worldwide, the demand for alternative drug sources and drug discovery has become an indispensable area of research. Seagrasses present a reliable natural source, making this an opportune moment for further exploration of their pharmacological activities with minimal side effects. This review provides a comprehensive overview of the biochemical, phytochemical, and biomedical applications of seagrasses globally over the last two decades, highlighting the prospective areas of future research for identifying biomedical applications. Full article

Marine ecosystems are important in discovering novel fungi with interesting metabolites that have shown great potential in pharmaceutical and biotechnological industries. Seagrasses, the sole submerged marine angiosperm, host diverse fungal taxa with mostly unknown metabolic capabilities. They are considered to be one of the least studied marine fungal habitats in the world. This review gathers and analyzes data from studies related to seagrasses-associated fungi, including taxonomy and biogeography, and highlights existing research gaps. The significance of the seagrass–fungal associations remains largely unknown, and current understanding of fungal diversity is limited to specific geographical regions such as the Tropical Atlantic, Mediterranean, and Indo-Pacific. Our survey yielded 29 culture-dependent studies on seagrass-associated endophytic and epiphytic fungi, and 13 miscellaneous studies, as well as 11 meta-studies, with no pathogenic true fungi described. There is a significant opportunity to expand existing studies and conduct multidisciplinary research into novel species and their potential applications, especially from understudied geographical locations. Future research should prioritize high-throughput sequencing and mycobiome studies, utilizing both culture-dependent and -independent approaches to effectively identify novel seagrass-associated fungal taxa. Full article

Seagrasses are marine angiosperms that inhabit tropical and subtropical regions around the world. They play a vital role in marine biodiversity and the ecosystem by providing habitats and food for several marine organisms, stabilizing sediments, and improving water quality. Halodule uninervis from the family Cymodoceaceae has been used in traditional folk medicine for the treatment of many ailments. Additionally, several identified bioactive metabolites have been shown to contribute to its pharmacological activities, including anticancer, anti-inflammatory, and antioxidant. As such, H. uninervis could contribute to the development of novel drugs for various diseases. This review aims to compile the phytochemical composition and pharmacological activities of H. uninervis. Furthermore, details about its botanical characteristics and ecological significance are also discussed. By providing valuable insights into the role of H. uninervis in both the marine ecosystem and biomedicine, this review helps to highlight its potential as a therapeutic agent for future drug discovery and development. Full article

The aim of the present study was to investigate the use of Posidonia oceanica for making products beneficial for human health. Firstly, we demonstrated that the antioxidant defense (i.e., SOD and APX activity) of P. oceanica’s living leaves (LP) has low efficacy, as they partly neutralize the produced H₂O₂. However, high H₂O₂ levels led LP to produce, as a response to oxidative stress, high phenolic content, including chicoric acid, p-coumaric acid, caftaric acid, trans-cinnamic and rutin hydrate, as shown by UHPLC-DAD analysis. In addition, LP extracts inhibited intestinal cancer cell proliferation. Moreover, P. oceanica’s beach casts consisting of either Wet ‘Necromass’ (WNP) or Dry ‘Necromass’ (DNP) were used for preparing extracts. Both DNP and WNP exhibited antioxidant and antiproliferative activities, although lower as compared to those of LP extracts. Although both P. oceanica’s meadows and beach casts are considered priority habitats in the Mediterranean Sea due to their high ecological value, legislation framework for beach casts forbidding their removal is still missing. Our results suggested that both LP and DNP could be utilized for the production of high-added value products promoting human health, provided that a sustainability management strategy would be applied for P. oceanica’s meadows and beach casts. Full article

Inflammation is a defense mechanism of the body in response to harmful stimuli such as pathogens, damaged cells, toxic compounds or radiation. However, chronic inflammation plays an important role in the pathogenesis of a variety of diseases. Multiple anti-inflammatory drugs are currently available for the treatment of inflammation, but all exhibit less efficacy. This drives the search for new anti-inflammatory compounds focusing on natural resources. Marine organisms produce a broad spectrum of bioactive compounds with anti-inflammatory activities. Several are considered as lead compounds for development into drugs. Anti-inflammatory compounds have been extracted from algae, corals, seaweeds and other marine organisms. We previously reviewed anti-inflammatory compounds, as well as crude extracts isolated from echinoderms such as sea cucumbers, sea urchins and starfish. In the present review, we evaluate the anti-inflammatory effects of compounds from other marine organisms, including macroalgae (seaweeds), marine angiosperms (seagrasses), medusozoa (jellyfish), bryozoans (moss animals), mollusks (shellfish) and peanut worms. We also present a review of the molecular mechanisms of the anti-inflammatory activity of these compounds. Our objective in this review is to provide an overview of the current state of research on anti-inflammatory compounds from marine sources and the prospects for their translation into novel anti-inflammatory drugs. Full article

Plant species usually have either annual or perennial life cycles, but facultative annual species have annual or perennial populations depending on their environment. In terrestrial angiosperms, facultative annual species are rare, with wild rice being one of the few examples. Our review shows that in marine angiosperms (seagrasses) facultative annual species are more common: six (of 63) seagrass species are facultative annual. It concerns Zostera marina, Z. japonica, Halophila decipiens, H. beccarii, Ruppia maritima, and R. spiralis. The annual populations generally produce five times more seeds than their conspecific perennial populations. Facultative annual seagrass species occur worldwide. Populations of seagrasses are commonly perennial, but the facultative annual species had annual populations when exposed to desiccation, anoxia-related factors, shading, or heat stress. A system-wide ‘experiment’ (closure of two out of three connected estuaries for large-scale coastal protection works) showed that the initial annual Z. marina population could shift to a perennial life cycle within 5 years, depending on environmental circumstances. We discuss potential mechanisms and implications for plant culture. Further exploration of flexible life histories in plant species, and seagrasses in particular, may aid in answering questions about trade-offs between vegetative and sexual reproduction, and preprogrammed senescence. Full article

The water lily (Nymphaea tetragona) is an ancient angiosperm that belongs to the Nymphaeaceae family. As a rooted floating-leaf plant, water lilies are generally cultivated in fresh water, therefore, little is known about their survival strategies under salt stress. Long-term salt stress causes morphological changes, such as the rapid regeneration of floating leaves and a significant decrease in leaf number and surface area. We demonstrate that salt stress induces toxicity soon after treatment, but plants can adapt by regenerating floating leaves that are photosynthetically active. Transcriptome profiling revealed that ion binding was one of the most-enriched GO terms in leaf-petiole systems under salt stress. Sodium-transporter-related genes were downregulated, whereas K⁺ transporter genes were both up- and downregulated. These results suggest that restricting intracellular Na⁺ importing while maintaining balanced K⁺ homeostasis is an adaptive strategy for tolerating long-term salt stress. ICP-MS analysis identified the petioles and leaves as Na-hyperaccumulators, with a maximum content of over 80 g kg⁻¹ DW under salt stress. Mapping of the Na-hyperaccumulation trait onto the phylogenetic relationships revealed that water lily plants might have a long evolutionary history from ancient marine plants, or may have undergone historical ecological events from salt to fresh water. Ammonium transporter genes involved in nitrogen metabolism were downregulated, whereas NO₃⁻-related transporters were upregulated in both the leaves and petioles, suggesting a selective bias toward NO₃⁻ uptake under salt stress. The morphological changes we observed may be due to the reduced expression of genes related to auxin signal transduction. In conclusion, the floating leaves and submerged petioles of the water lily use a series of adaptive strategies to survive salt stress. These include the absorption and transport of ions and nutrients from the surrounding environments, and the ability to hyperaccumulate Na⁺. These adaptations may serve as the physiological basis for salt tolerance in water lily plants. Full article

The catch per unit effort (CPUE), population structure, sex ratio, and reproductive aspects of the invasive blue crab Callinectes sapidus Rathbun were studied in Monolimni Lagoon and the adjacent coastal waters in the estuarine area of the Evros River (Northeast Aegean Sea, Eastern Mediterranean). The CPUE varied both seasonally and spatially; higher values were recorded in summer and fall in the lagoonal stations characterized by shallow depth (<0.5 m) and a dense meadow of the angiosperm Ruppia maritima, whereas significantly lower CPUE was recorded in the adjacent coastal area. The bottom temperature was positively correlated with CPUE. Μodal progression analysis estimated a three-modal size–frequency distribution for both sexes corresponding to the 0⁺, 1⁺, and 2⁺ age classes. Females attained a significantly larger size (carapace width (CW)) than males. Crab size decreased from the marine area to the lagoonal stations. The sex ratio was estimated at 2.45:1 (♂/♀). Males dominated in all months, except for October, when an equal sex ratio was observed. The mean size at maturity (L₅₀) of females was estimated at 124 mm CW. Females with mature ovaries were found from February to October. Ovigerous females were observed from May to October in the coastal area, where a spawning peak occurred in September. In the Evros River estuary, the American blue crab exhibits a life cycle that seems to conform to the general complex life-cycle pattern of the species along the mid-Atlantic coast. Full article

Seagrasses are marine angiosperms, and seagrass beds maintain the species diversity of tropical and subtropical coastal ecosystems. For proper understanding, management and conservation of coastal ecosystems, it is essential to understand seagrass population dynamics. Population genetic studies can cover large geographic scales and contribute to a comprehensive understanding of reproductive dynamics and potential dispersal among locations. The clonal and genetic diversity and genetic connectivity of Thalassia hemprichii in the Philippines were estimated by a population genetics approach. The geographic scale of this study has a direct distance of approximately 1600 km. Although high clonal diversity was found in some sites (R = 0.07–1.00), both sexual and asexual reproduction generally maintains separate populations. Genetic diversity is not definitely correlated with latitude, and genetic differentiation is significant in all pairs of sites (F_ST = 0.026–0.744). Complex genetic structure was found in some regions, even at a fine geographic scale. The migration of fruits and seedlings was elucidated as an infrequent and stochastic event. These results suggest the necessity for the conservation of this species due to a deficiency in migrants from external regions. Full article

Marine angiosperms produce a wide variety of secondary metabolites with unique structural features that have the potential to be developed as effective and potent drugs for various diseases. Recently, research trends in secondary metabolites have led to drug discovery with an emphasis on their pharmacological activity. Among marine angiosperms, seagrasses have been utilized for a variety of remedial purposes, such as treating fevers, mental disorders, wounds, skin diseases, muscle pain, and stomach problems. Hence, it is essential to study their bioactive metabolites, medical properties, and underlying mechanisms when considering their pharmacological activity. However, there is a scarcity of studies on the compilation of existing work on their pharmacological uses, pharmacological pathways, and bioactive compounds. This review aims to compile the pharmacological activities of numerous seagrass species, their secondary metabolites, pharmacological properties, and mechanism of action. In conclusion, this review highlights the potency of seagrasses as a promising source of natural therapeutical products for preventing or inhibiting human diseases. Full article

The effects of environmentally relevant bisphenol A (BPA) concentrations (0.3, 1 and 3 μg L⁻¹) were tested at 2, 4, 6 and 8 days, on intermediate leaves, of the seagrass Cymodocea nodosa. Hydrogen peroxide (H₂O₂) production, lipid peroxidation, protein, phenolic content and antioxidant enzyme activities were investigated. Increased H₂O₂ formation was detected even at the lowest BPA treatments from the beginning of the experiment and both the enzymatic and non-enzymatic antioxidant defense mechanisms were activated upon application of BPA. Elevated H₂O₂ levels that were detected as a response to increasing BPA concentrations and incubation time, led to the decrease of protein content on the 4th day even at the two lower BPA concentrations, and to the increase of the lipid peroxidation at the highest concentration. However, on the 6th day of BPA exposure, protein content did not differ from the control, indicating the ability of both the enzymatic and non-enzymatic mechanisms (such as superoxide dismutase (SOD) and phenolics) to counteract the BPA-derived oxidative stress. The early response of the protein content determined that the Low Effect Concentration (LOEC) of BPA is 0.3 μg L⁻¹ and that the protein content meets the requirements to be considered as a possible early warning “biomarker” for C. nodosa against BPA toxicity. Full article