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The marine algae Ulva spp. are commonly used as model biofouling organisms. As biofouling studies are primarily conducted using field-collected specimens, factors including species identity, seasonal availability, and physiological status can hinder the replicability of the results. To address these limitations, a protocol was developed for the on-demand laboratory culture and release of Ulva zoospores. The biofouling potential of laboratory-cultured and field-collected Ulva blades was compared using a waterjet. No significant differences were found between field and laboratory-cultured samples in either spore adhesion (before waterjet) or the proportion of spores retained after waterjet exposure. However, there was significant variability within each session type in pre- and post-waterjet exposures, indicating that spore adhesion and retention levels vary significantly among trial runs. In addition, all our laboratory cultures were Ulva Clade C (LPP complex). In contrast, our field samples contained a mix of Ulva Clade C, U. compressa clade I, and U. flexuosa Clade D. This protocol for on-demand production of Ulva spores can improve biofouling research approaches, enables comparison of results across laboratories and regions, and accelerate the development of anti-biofouling strategies. [ABSTRACT FROM AUTHOR]

This study set out to provide a preliminary assessment of nutritional profiles of five selected New Zealand macroalgae to investigate the potential of landcultivated Ulva spp. The New Zealand seaweeds species, selected from a limited range, were either collected from the wild (Pyropia plicata from Tauranga and Kaikōura), or were sourced from commercial wild harvest suppliers (Macrocystis pyrifera and Undaria pinnatifida), and were compared to land-based cultivated Ulva species (Ulva ralfsii and Ulva stenophylloides). Species were assessed for their content of crude protein, total lipids, carbohydrates, fibers, amino acids, mineral profiles, heavy metals and antioxidant capacity (Oxygen Radical Absorbance Capacity, ORAC). The two cultivated Ulva spp. had the highest crude protein content of the six seaweeds analyzed (approximately 21% dw, N×6.25), as expected with nutrient supplemented cultivation. They also had the highest total, essential and branched chain amino acid quantities (151, 70, and 29 mg/g for U. stenophylloides and 138, 62, and 27 mg/g for U. ralfsii). Though the two Ulva spp. were grown to the same cultivation specifications, they varied in carbohydrate and total fiber content (U. stenophylloides: 63% and 62%; U. ralfsii: 39% and 40%, respectively). Pyropia plicata collected in Kaikōura had the highest carbohydrate levels (65%) though not the highest total fiber. Both P. plicata had the highest trace minerals (417 mg/kg and 720 mg/kg for Kaikōura and Tauranga P. plicata respectively). All seaweeds analyzed showed no lipophilic antioxidants, though the two Phaeophyceae had the highest hydrophilic antioxidant content at 115 TE and 168 TE for Macrocystis pyrifera and Undaria pinnatifida, respectively. This paper provides a preliminary indication of the relative nutritional attributes of a range of potential New Zealand seaweed aquaculture targets benchmarked against sealettuce (Ulva spp.). [ABSTRACT FROM AUTHOR]

The present study provides information on the effects of BPA on ROS production-related phenomena in the chlorophytes Ulva rigida and U. intestinalis, and on the mechanism they establish against BPA toxicity, at environmentally relevant concentrations (0.1–3 μg L−1). Up-regulated H2O2 generation seems to be a key factor causing oxidative damage. Interspecific differences, in terms of the mechanism and the temporal response to BPA toxicity were observed. BPA effects on U. rigida were more intense and appeared earlier (on 1D at 0.1 μg L−1) compared to U. intestinalis and mostly after 7D (LOEC: 0.3 μg L−1, Terminal time, Tt: 7D). In U. rigida, on 1-5D, the 'mosaic' type effect patterns ('models' 3A/3B) with 'unaffected' and 'affected' areas (dark content, positive H2DCF-DA staining signal/H2O2 production and chlorophyll autofluorescence signal loss) indicated a time-dependent manner. After 7D, only U. rigida cells with dark content formed aggregates, showing positive H2O2 production ('model' 4) or in some cells oxidative damages triggering retrograde signaling in the neighboring 'unaffected' areas ('model' 5). H2O2 overproduction (CTCF ratio) in U. rigida, on 1D at the lowest concentration and after 7D at 0.3–1/3 μg L−1, respectively, seems to stimulate (poly)phenolic production, in a dose- and time-dependent manner. U. intestinalis did not display severe BPA impact (i.e., 'models' 4, 5) at any exposures, although at a later time indicated a lower LOEC (0.1 μg L−1, Tt: 9D) than that in U. rigida. In U. intestinalis, H2O2 production does not appear to stimulate high (poly)phenolic amounts. [ABSTRACT FROM AUTHOR]

Basket height and stocking density are crucial and related factors for successful commercial sea urchin aquaculture, but these factors have not been definitively determined for production of Tripneustes gratilla. This study investigated the effects of varying basket heights (deep 30 cm vs. shallow 15 cm) and stocking densities (4, 6 and 8 kg.m−2 or 13, 19 and 24% coverage of available basket surface area) on aquacultural production of T. gratilla. Contrary to previous suggestions, reduced consumption was identified as the cause of decreased production in deeper baskets. Consumption was significantly higher in shallow baskets than deep baskets for both the fresh seaweed, Ulva lacinulata, (W = 38, p = 0.026) and formulated feed (W = 76.5, p = 0.007). Consequently, baskets of approximately 15 cm deep are recommended to enhance production of T. gratilla and possibly other urchin species. Two subsequent trials assessed production of T. gratilla at different stocking densities. Trial 1 aimed to maximize urchin size over a three-month grow-out period using fresh U. lacinulata, while trial 2 focused on enhancing gonad production over two months using formulated feed. Although greater stocking density significantly reduced the specific growth rates of individual urchin mass in both trials (p < 0.044), there was no significant impact on mortality, net production or gonad size and quality. The variations in growth rates were attributed to spine loss resulting from negative behavioural interactions (F2, 9 = 9.551; p = 0.005). Based on the objectives of both grow-out and gonad-enhancement phases, we recommend a stocking density of approximately 20% coverage. [ABSTRACT FROM AUTHOR]

Macroalgae seaweeds such as Ulva lactuca and Gracilaria verrucosa cause problems on the northern coast of the Italian Adriatic Sea because their overabundance hinders the growth of cultivated clams, Rudatapes philippinarum. This study focused on the green synthesis of CuO nanoparticles from U. lactuca and G. verrucosa. The biosynthesized CuO NPs were successfully characterized using FTIR, XRD, HRTEM/EDX, and zeta potential. Nanoparticles from the two different algae species are essentially identical, with the same physical characteristics and almost the same antimicrobial activities. We have not investigated the cause of this identity, but it seems likely to arise from the reaction of Cu with the same algae metabolites in both species. The study demonstrates that it is possible to obtain useful products from these macroalgae through a green synthesis approach and that they should be considered as not just a cause of environmental and economic damage but also as a potential source of income. [ABSTRACT FROM AUTHOR]

This study was conducted to determine whether the macroalgae Ulva papenfussi and Ulva nematoidea could be alternatives for preventing Litopenaeus vannamei vibriosis caused by the bacterium Vibrio parahaemolyticus. Phytochemical screening was performed on methanolic extracts to qualitatively determine the main groups of bioactive compounds, previous to an in vitro antibacterial test against V. parahaemolitycus. Phenols, polyphenols, flavonoids, and the high presence of carbohydrates were found in both macroalgae. U. papenfussi showed more presence of lipids and alkaloids than U. nematoidea. Macroalgae extracts prepared (v:v) with a 1:1 methanol: dichloromethane solvent was used for the in vitro test using the disc diffusion method (MDD). Filter paper discs impregnated with 1.0, 1.5, 2.0, 3.0, and 4.0 mg of the extracts showed antibacterial activity against V. Parahaemolitycus in a dose-dependent manner in both macroalgae. The inhibition zone varied significantly (p < 0.05) from 8.33 ± 0.12 to 11.41 ± 0.73 mm for 1 to 3 mg of extract levels, respectively. In conclusion, both macroalgae have antibacterial activity in their crude extracts against this bacteria. It is suggested to evaluate it as a feed additive for L. vannamei. This study is the first report on a phytochemical screening and antibacterial activity of these macroalgae against V. parahaemolyticus. [ABSTRACT FROM AUTHOR]

Ulva rigida green macroalgae contain a variety of polysaccharides. A recent study investigated the optimum concentration and yield of polysaccharide extraction from oven-dried U. rigida biomass using a water-soluble polysaccharide extraction method that adhered to safety standards. This study utilised complete factorial experiments to examine the effects of varying factors on polysaccharide extraction. Results showed a positive correlation between increased levels of all factors and higher polysaccharide extraction yield. This study also found that the main factors and their interaction had a significant impact on the extracted polysaccharides from U. rigida. The highest polysaccharide content and yield were 9.5 mg/mL and 189 mg/g, respectively. Water-soluble polysaccharides demonstrated the presence of reducing sugar (8 mg/g), phenolics (0.69 mg/g) and flavonoids (1.42 mg/g) and exhibited antioxidant properties. Results revealed that freeze-dried polysaccharide powders were primarily composed of the monosaccharide rhamnose. Preliminary results on the effect of these powders on probiotics demonstrated that supplementation of polysaccharides from U. rigida promoted viable Lactobacillus rhamnosus ATCC 53103 growth during cultivation. This discovery has the potential to revolutionise the human food industry and promote the development of functional ingredients for novel and future food products, with numerous applications in the nutraceutical and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

The bacterial communities related to seaweed can vary considerably across different locations, and these variations influence the seaweed's nutrition, growth, and development. To study this further, we evaluated the bacteria found on the green marine seaweed Ulva prolifera from Garorim Bay and Muan Bay, two key locations on Republic of Korea's west coast. Our analysis found notable differences in the bacterial communities between the two locations. Garorim Bay hosted a more diverse bacterial population, with the highest number of ASVs (871) compared to Muan Bay's 156 ASVs. In Muan Bay, more than 50% of the bacterial community was dominated by Pseudomonadota. On the other hand, Garorim Bay had a more balanced distribution between Bacteroidota and Pseudomonadota (37% and 35.5%, respectively). Additionally, Cyanobacteria, particularly Cyanothece aeruginosa, were found in significant numbers in Garorim Bay, making up 8% of the community. Mineral analysis indicated that Garorim Bay had higher levels of S, Na, Mg, Ca, and Fe. Function-wise, both locations exhibited bacterial enrichment in amino acid production, nucleosides, and nucleotide pathways. In conclusion, this study broadens our understanding of the bacterial communities associated with Ulva prolifera in Korean waters and provides a foundation for future research on the relationships between U. prolifera and its bacteria. [ABSTRACT FROM AUTHOR]

Macroalgae are considered healthy food ingredients due to their content in numerous bioactive compounds, and the traditional use of whole macroalgae in Asian cuisine suggests a contribution to longevity. Although much information is available about the bioactivity of pure algal compounds, such as different polyphenols and polysaccharides, documentation of potential effects of whole macroalgae as part of Western diets is limited. Lifestyle- and age-related diseases, which have a high impact on population health, are closely connected to underlying chronic inflammation. Therefore, we have studied crude extracts of green (Ulva fenestrata) and brown (Saccharina latissima) macroalgae, as two of the most promising food macroalgae in the Nordic countries for their effect on inflammation in vitro. Human macrophage-like reporter THP-1 cells were treated with macroalgae extracts and stimulated with lipopolysaccharide (LPS) to induce inflammatory signalling. Effects of the macroalgae extracts were assessed on transcription factor activity of NF-κB and IRF as well as secretion and/or expression of the cytokines TNF-α and IFN-β and chemokines IL-8 and CXCL10. The crude macroalgae extracts were further separated into polyphenol-enriched and polysaccharide-enriched fractions, which were also tested for their effect on transcription factor activity. Interestingly, we observed a selective activation of NF-κB, when cells were treated with macroalgae extracts. On the other hand, pretreatment with macroalgae extracts selectively repressed IRF activation when inflammatory signaling was subsequently induced by LPS. This effect was consistent for both tested species as well as for polyphenol- and polysaccharide-enriched fractions, of which the latter had more pronounced effects. Overall, this is the first indication of how macroalgae could modulate inflammatory signaling by selective activation and subsequent repression of different pathways. Further in vitro and in vivo studies of this mechanism would be needed to understand how macroalgae consumption could influence the prevention of noncommunicable, lifestyle- and age-related diseases that are highly related to unbalanced inflammatory processes. [ABSTRACT FROM AUTHOR]

In 2022, Yellow Sea green tide caused by Ulva prolifera reached a historic minimum and the coastal areas of Shandong Peninsula were less affected. However, the largest amount of seaweed biomass has been washed ashore on Lianyungang and Rizhao coasts since 2015. We studied the development pattern of Yellow Sea green tide in 2022, and analyzed the key environmental factors on the growth and drifting, then discussed the possible reasons that resulted in the massive stranding of green tide biomass in Lianyungang and Rizhao. Results show under the combined influence of the east to southeast winds and currents with shoreward anomalies, green tide drifted to the coastal waters between Shandong and Jiangsu provinces and the distribution areas located westward compared with previous years (2008–2021). Floating U. prolifera rafts from the coastal waters of Binhai and Sheyang drifted continuously into the coastal waters of Lianyungang and Rizhao, providing important supplements for Yellow Sea green tide. Because green tide in 2022 distributed close to the coastal waters, the abundant nutrients might support their continuous high growth rate. In addition, the amount of rainfall around Shandong Peninsula from late June to early July were significantly higher than in previous years, which might promote the development of green tide to some extent. [ABSTRACT FROM AUTHOR]

Benefits of integrated shrimp/seaweed culture systems have been investigated; nevertheless, knowledge of the importance of microorganisms in the systems is limited. In the present study, we evaluated shrimp Litopenaeus vannamei under four experimental conditions: fed pelleted diet in the presence of Ulva lactuca with (UPE) and without water exchange (UPN) and fed only a pelleted diet with (PE) and without water exchange (PN). Bacterial communities present in shrimp, seaweed, and water were analyzed after 4 weeks of an experimental trial. Our results showed significantly lower shrimp final weight, weight gain, specific growth rate (SGR), and higher feed conversion ratio (FCR) with PN treatment compared to the rest of the treatments (P < 0.05). Seaweed resulted in lower relative abundance of Vibrio in the presence of shrimp (UPE and UPN) compared to monoculture (Ulv). Shrimp intestine presented lower Vibrio and significantly increased Sagittula and Lutimonas in treatments without water exchange. In the case of shrimp fed only pellet with water exchange (PE), a significantly higher relative abundance of Lucibacterium and Planctomicrobium genera was found compared to PN, UPE, and UPN treatments. The results suggest that the seaweed in a system with no water exchange is advantageous to promote water bacterial diversity, and that reduces the relative abundance of Vibrio in shrimp gut. Additionally, PERMANOVA analyses revealed that both seaweed presence and water exchange are significant factors in structuring the culture system microbiota (P < 0.001). The present study contributes to understanding the importance of microbial communities in shrimp/seaweed integrated aquaculture systems. [ABSTRACT FROM AUTHOR]

This document is a summary of a special issue of the journal Botanica Marina focused on the green seaweed Ulva. The collection of articles explores various aspects of Ulva, including its ecology, phylogeny, and practical applications in aquaculture. The articles cover topics such as taxonomy, cross-kingdom interactions with bacteria and fungi, and the cultivation of Ulva for sustainable alternatives to essential fatty acids. The special issue aims to advance our understanding of Ulva and its potential in sustainable aquaculture and ecological contexts. The collection is dedicated to the late Prof. Dr. Klaus Lüning, a renowned marine botanist who made significant contributions to the study of Ulva. The special issue is also supported by the EU-funded COST Action SeaWheat, which aims to integrate Ulva into various industries and daily life. [Extracted from the article]

Several studies have shown that endophytic fungal metabolites possess vital biological activities; nevertheless, there is a lack of knowledge regarding the medicinally important marine endophytic fungi associated with the seaweeds mainly found in the Bay of Bengal, Bangladesh. In this study, six endophytic fungi, belonging to five genera and four classes, were isolated from the well-known chlorophyte, Ulva sp. and were most closely related to Chaetomium globosum, Nigrospora magnoliae, Curvularia sp., Curvularia moringae, Aspergillus terreus and Collariella sp. This is the first report of these fungi as endophytes associated with Ulva sp. from the Bay of Bengal, Bangladesh. A preliminary biological evaluation of the ethyl acetate extract of each endophytic fungal crude extract was the prime objective of this research, e.g., antimicrobial assay, 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity and brine shrimp lethality bioassay. Evaluation of test results revealed that each fungal crude extract possessed one or more relevant biological activities. Preliminary chemical screening using TLC and NMR spectroscopic analysis revealed the presence of several secondary metabolites in the crude fungal extracts. These findings suggest that the marine endophytic fungus may be a valuable source for investigating potentially bioactive chemicals or leads for novel drug candidates. [ABSTRACT FROM AUTHOR]

When emersed, intertidal seaweeds experience rapid changes in environmental conditions. On warm sunny days, seaweeds can desiccate soon after emersion. On rainy days or in areas with freshwater inputs, they may experience rapid drops in salinity. To determine whether one low tide's exposure to environmental stress alters seaweed growth, palatability to herbivores, and dimethylsulfoniopropionate (DMSP) concentrations, we exposed Ulva fenestrata to desiccation and hyposaline conditions for 3 h in summer and winter. Two days later, summer desiccation decreased growth, consumption by Lacuna vincta, and DMSP by 71%, 83%, and 67%, relative to controls. Winter desiccation reduced DMSP by 19% and did not affect growth or L. vincta feeding. Summer hyposaline conditions increased growth by 75% but did not affect L. vincta grazing or DMSP, whereas winter hyposaline conditions reduced growth by 37%. After 2 days of exposure to L. vincta, seaweeds were allowed to recover for 7 days, then DMSP was measured. U. fenestrata desiccated in the summer did not survive. Average DMSP concentrations were 127% higher in grazed than ungrazed seaweed in the summer salinity experiment, providing evidence that grazing induces DMSP. No DMSP induction occurred in winter, possibly because grazing rates were much lower. In a follow-up summer desiccation experiment, maximum quantum yields (MQYs) and DMSP decreased to 12% and 14% of controls within an hour. After 7 days, MQY and DMSP concentrations recovered, but growth was 81–97% lower in seaweeds desiccated for 30–60 min, relative to controls. These results provide the first evidence for grazer-induced DMSP increases. [ABSTRACT FROM AUTHOR]

Edible green algal species are the most widely distributed and diverse macroalgae in the world and are considered as an important source of bioactive molecules which serve as multi-product sources for nutritional and pharmaceutical applications. The present investigations were carried out concerning biochemical constituents from three species of green marine algae Ulva conglobata, Caulerpa racemosa, and Bryopsis plumosa collected from the coast of Veraval Chowpati, Gujarat India. The biochemical composition was analysed using uv-spectrophotometer to evaluate its food value and find out variations in composition during the investigation period. The reducing sugar, proline, and starch contents were high in Bryopsis plumosa followed by Caule rpa racemosa and Ulva conglobata. Proline content is higher than the total amino acids in three algal species. The protein contents following by Lowry method Caulerpa racemosa have a high amount with 1667.32 ± 18.42 (µgg-1 dry wt.) followed by Bryopsis plumosa 1394.98 ± 18.78 (µgg-1 dry wt.) and Ulva conglobata 292.72 ± 17.85 (µgg-1 dry wt.). The protein content was recorded maximum in Bryopsis plusmosa and Caulerpa racemosa than in the Ulva conglobata. All the assays carried out in the present work showed that all selected green algae are good sources of biochemical. According to the biochemical composition values of the studied algae, they have the potential to be a source of constituents with high nutritional value and use in the food, dietary, and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Background: Solar radiation is primarily composed of ultraviolet radiation (UVR, 200 − 400 nm) and photosynthetically active radiation (PAR, 400 − 700 nm). Ultraviolet-B (UVB) radiation accounts for only a small proportion of sunlight, and it is the primary cause of plant photodamage. The use of chlorofluorocarbons (CFCs) as refrigerants caused serious ozone depletion in the 1980s, and this had led to an increase in UVB. Although CFC emissions have significantly decreased in recent years, UVB radiation still remains at a high intensity. UVB radiation increase is an important factor that influences plant physiological processes. Ulva prolifera, a type of macroalga found in the intertidal zone, is intermittently exposed to UVB. Alternative oxidase (AOX) plays an important role in plants under stresses. This research examines the changes in AOX activity and the relationships among AOX, photosynthesis, and reactive oxygen species (ROS) homeostasis in U. prolifera under changes in UVB and photosynthetically active radiation (PAR). Results: UVB was the main component of solar radiation impacting the typical intertidal green macroalgae U. prolifera. AOX was found to be important during the process of photosynthesis optimization of U. prolifera due to a synergistic effect with non-photochemical quenching (NPQ) under UVB radiation. AOX and glycolate oxidase (GO) worked together to achieve NADPH homeostasis to achieve photosynthesis optimization under changes in PAR + UVB. The synergism of AOX with superoxide dismutase (SOD) and catalase (CAT) was important during the process of ROS homeostasis under PAR + UVB. Conclusions: AOX plays an important role in the process of photosynthesis optimization and ROS homeostasis in U. prolifera under UVB radiation. This study provides further insights into the response of intertidal macroalgae to solar light changes. [ABSTRACT FROM AUTHOR]

Ulee Lheue Beach in Banda Aceh was developed for tourism. The macroalgae and seaweed species found in this area have been widespread but never exploited. Among these species is the green seaweed, Ulva lactuca, commonly known as sea lettuce. The physiological variations and genetic features of the seaweed can be attributed to the variations in the coastal environment. This study aims to describe the molecular identity of the genetic diversity of U. lactuca from the intertidal zone at Ulee Lheue Beach. The development of molecular biotechnology has enabled identification the gene expression through genomic DNA to PCR amplification. Genetic distance was determined using UPGMA. The results from 600-bp fragments were analyze the genetic diversity. A total of 15 (31%) expression identified as polymorphic (>0.500). Heterozygosity (He) and allelic differential (Na) diversity were found of 1.500-3.000. The highest PIC was observed in the rbcL1, with a correlation between subpopulations of 0.459. PCR amplification using the degenerate primer rbcL1 produced fragments ranging from 300 to 460 bp, whereas the expression of UL2 was detected at 448 and 500 bp using the rbcL2 primer. The phylogenetic identify are shown two (2) clusters. The populations of UL1, UL3, and UL4 were found a close relationship. Furthermore, the UL1 and UL2 populations were further divided into distinct clusters but related to the main branch of UL3. Based on this research, the concern of U. lactuca species for industrial and biotechnology destinations, we can describe a suitable method for obtaining he genetic distances between species. [ABSTRACT FROM AUTHOR]

This study investigates the potential utility of Ulva fasciata biomass for biohydrogen production and its disintegration under ultrasonic disintegration (UD), and ultrasonic combined surfactant disintegration (UCSD). SCOD release and specific energy consumption were evaluated for UD and UCSD. In UCSD, optimal surfactant addition was 10 μl, 160 W sonication power, and 30-min sonication time resulted in a maximum release of SCOD of 1030 mg/L and a maximum solubilization of 21.2% to compare the performance of UD and UCSD, biopolymer release was analyzed. The maximum protein and carbohydrate release was 680 mg/L and 224.2 mg/L the disintegrated substrate was evaluated for its biohydrogen production under anaerobic conditions with both UD and UCSD. As compared to UD (90.4 mL), and control (17.3 mL), UCSD (121.6 mL) produced more biohydrogen. According to its energy analysis, UCSD had a positive net energy of 0.012 kW h/kg and an energy ratio of 1.375. This study also reveals that macroalgae U. fasciata could be a sustainable renewable energy source for biohydrogen production. • Biohydrogen production from Ulva fasciata, a macroalgal source. • A higher biomass liquefaction of 21.2% was found in combined pretreatment. • Surfactant-mediated pretreatment significantly improves biohydrogen production. • Net energy of combined pretreatment is higher than ultrasonic alone. [ABSTRACT FROM AUTHOR]

In a closed, or zero water exchange, greenhouse aquaculture system, this study examined the interaction between the aggregation flocs in the mono- and co-cultivation of Pasific white shrimp, Litopenaeus vannamei (300 individuals/m3) with macroalgae, Ulva lactuca f. fasciata at different densities of Ulva (1, 2 and 3 g/l). The investigation was conducted under zero water exchange conditions. The accumulated flocs were compared between the various treatment groups: without Ulva (Treatment Control Group), Ulva at 1 g/l density (T1: Treatment 1), Ulva at 2 g/l (T2: Treatment 2), and Ulva at 3 g/l (T3: Treatment 3). Ultimately, it was determined that Ulva cultivation using the Biofloc system actually helped to ensure the water quality in the zero water exchange culture system during the 35-day experimental period with reduced cyanophyte densities, that can cause toxic algal blooms in aquaculture systems. This was interpreted to result from the fact that Ulva is a naturally occurring bioremediation agent. [ABSTRACT FROM AUTHOR]

The concept of floating algae index (FAI), a measure of the red-edge reflectance of floating vegetation, has been used to map floating macroalgae in global oceans. However, when the algae mats are submerged in water due to winds and other factors, the reduced reflectance (and thus reduced FAI value) is interpreted as being caused by reduced areal density (or biomass density) of algae, leading to underestimated algae amount. Here, a depth invariant FAI is proposed to overcome this difficulty. The depth invariant FAI is formulated using three spectral bands whose selective water attenuations can compensate for the reduced reflectance, resulting in FAI values that are nearly independent of the submerged depth of up to 30 cm with underestimates of the algae amount reduced from >50% to a few percent. In this study, the concept of depth invariant FAI is demonstrated through simulations only. With the new Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission and other hyperspectral satellite missions in the near future, such a concept is expected to be tested and evaluated with satellite data, from which the optimal bands can be selected to reduce uncertainties in mapping floating macroalgae. [ABSTRACT FROM AUTHOR]

Seaweed, or macroalgae, is a diverse group of marine plants found in various aquatic environments. Seaweed has gained attention due to its potential uses in various industries, including food, agriculture, pharmaceuticals, etc. Its proximate composition refers to the essential nutritional components that make up seaweed. The present study aimed to conduct proximate composition analysis on three different seaweeds, Valonia utricularis, Ulva reticulata and Kappaphycus alvarezii, collected from the Mandapam region coast, Rameshwaram, Tamil Nadu, India. A result of three seaweeds Valonia utricularis, Ulva reticulata and Kappaphycus alvarezii was followed ash (23.42% DW), (22.19%) and (19.7%DW). Protein was (11.5% DW), (10.11%) and (15.91%DW); lipid content was (4.24% DW), (5.27%) and (2.75%DW); crude fibre was (12.72% DW), (16.20%) and (23.51%DW); carbohydrate (31.33% DW), (27.05%) and (26.19 %DW), Total Dietary Fiber was (2.7% DW), (3.03%) and (6.76% DW). [ABSTRACT FROM AUTHOR]

Marine based organisms and their bioactive compounds are very attractive in terms of biomedical area. Due to marine ecosystem have harsh environment conditions; marine algae synthesize various bioactive compounds to survive. Genus Ulva (green macro algae) or sea lettuce species are the most abundant representatives abound in coastal waters and have various bioactive compounds. Therefore, Ulva sp. is extensively researched in especially cancer treatment. In this study, the ethanol extract of Ulva rigida C. Agardh collected from Izmir Bay was investigated by MTT, LDH, TAC, TOS and HET-CAM assays to determine its anticancer potential. The extract of U. rigida showed significant cytotoxic effect on human cervix adenocarcinoma (HeLa) cells (IC50 value is 21 ± 4.84 mg/L). The extract had a moderate anti-angiogenic activity (Score value is 0.98 ± 0.3 at 50 μM concentration). Our results showed that U. rigida has a good potential cervical cancer therapy agent. [ABSTRACT FROM AUTHOR]

Unialgal stock cultures for seeding the tank water can be used for the mass cultivation of seaweeds in artificial seawater, as in microalgal mass cultivation. High costs for artificial sea salt mixtures and distilled water would be required, however, to use artificial seawater in big tanks for commercial purposes, but frequent medium changes may not be required, since the major ions contained in artificial seawater, such as sodium, will barely be utilised by the cultured algae during long periods of time, even over years. Similar growth rates were obtained at the start and end of an experiment conducted with Ulva pseudocurvata cultivated unialgally for two years without water change, at a low algal density and with weekly addition of Provasoli Enrichment. Growth in this experiment was increasingly impeded due to gamete swarming events causing dark greenish water every few weeks. The experimental water had then to be boiled in order to kill the gametes. In a second experiment, this time performed at a high algal density, maximum yield values were 20–30 g fresh weight m−2 d−1, both for 2-year-old and newly prepared artificial seawater. These results verified the hypothesis that long-term Ulva cultivation in artificial seawater is possible without frequent medium changes. [ABSTRACT FROM AUTHOR]

Ulva prolifera and Sargassum are two common floating macroalgae in China's coastal algal bloom events. Ulva prolifera frequently emerges concomitantly with Sargassum outbreaks, thereby presenting challenges to the monitoring of algal blooms, thereby presenting challenges to the monitoring of algae. To tackle the challenge of differentiating between Ulva prolifera and Sargassum, this study employs Sentinel-2 MSI data for spectral analysis. Notably, significant disparities in the Remote Top of Atmosphere Reflectance (Rtoa) between Ulva prolifera and Sargassum are observed. This study proposes a random forest-based algorithm for discriminating between Ulva prolifera and Sargassum in the regions of the Yellow Sea and East China Sea. The algorithm introduced in this study attains remarkable accuracy in distinguishing Ulva prolifera and Sargassum within Sentinel-2 MSI data, achieving identical F1 scores of 99.1% for both. Moreover, when tested with GF-1 WFV data, the algorithm showcases outstanding performance; this demonstrates the algorithm's robustness and its ability to mitigate the uncertainty linked to threshold selection. Simultaneously, a comparative analysis of algae distribution was conducted for both 2017 and the period from January to May 2023. Experimental results indicate that the algorithm exhibits high accuracy in distinguishing between Ulva prolifera and Sargassum. This capability will significantly enhance the monitoring of large algae in maritime regions; this holds crucial theoretical significance and offers substantial practical value in the realm of marine ecological conservation. [ABSTRACT FROM AUTHOR]

Ulvan is a sulfated polysaccharide extracted from green macroalgae with unique structural and compositional properties. Due to its biocompatibility, biodegradability, and film-forming properties, as well as high stability, ulvan has shown promising potential as an ingredient of biopolymer films such as sustainable and readily biodegradable biomaterials that could replace petroleum-based plastics in diverse applications such as packaging. This work investigates the potential of Ulva fenestrata as a source of ulvan. Enzyme-assisted extraction with commercial cellulases (Viscozyme L and Cellulysin) and proteases (Neutrase 0.8L and Flavourzyme) was used for cell wall disruption, and the effect of the extraction time (3, 6, 17, and 20 h) on the ulvan yield and its main characteristics (molecular weight, functional groups, purity, and antioxidant capacity) were investigated. Furthermore, a combined process based on enzymatic and ultrasound extraction was performed. Results showed that higher extraction times led to higher ulvan yields, reaching a maximum of 14.1% dw with Cellulysin after 20 h. The combination of enzymatic and ultrasound-assisted extraction resulted in the highest ulvan extraction (17.9% dw). The relatively high protein content in U. fenestrata (19.8% dw) makes the residual biomass, after ulvan extraction, a potential protein source in food and feed applications. [ABSTRACT FROM AUTHOR]

Many algae respond to the CO2 limitation in seawater by inducing a CO2 concentrating mechanism (CCM) to obtain sufficient inorganic carbon to meet their photosynthetic needs, and Ulva sp. is a model population suitable for studying the ecological adaptability of macroalgae. As the dominant species of green tide disaster, Ulva sp. often faces strong inorganic carbon restriction due to its rapid growth and high population density and must have evolved a variety of carbon acquisition strategies, such as CCM, to overcome these limitations. This paper briefly summarizes the position and function of the important components of CCM (inorganic carbon transporters, carbonic anhydrase, Rubisco, and pyrenoid) and introduces several indexes suitable for evaluating the relative function of CCMs in macroalgae from the aspects of affinity between photosynthesis and Rubisco for CO2, and carbonic anhydrase inhibitor. The methods of judging the carbon sequestration pathway of Ulva sp., the CCM responses of diversity under different carbon sources, and the related genes that may be involved in the operation of CCMs were summarized. This work could provide a reference for revealing the CCMs of macroalgae and lay a foundation for further research on the inorganic carbon utilization strategy of the Ulva sp. [ABSTRACT FROM AUTHOR]

Ulva is one of the main green algae causing green tide disasters. Ulvan is the primarily component polysaccharide of the cell wall of Ulva and its complex structure and monosaccharide composition resulted in various biological activities. However, the high-value and effective utilization of extracted ulvan have been obstructed by limitations ranging from large molecular weight and low solubility to poor bioavailability. Ulva oligosaccharide obtained by degrading ulvan can not only ideally retain the various biological activities of ulvan very well but also effectively solve the problems of low solubility and poor bioavailability. The preparation and biological activity studies of ulvan and Ulva oligosaccharides have become a hot spot in the field of marine biological resources development research. At present, the comprehensive reviews of ulvan and Ulva oligosaccharides are still scarce. What are overviewed in this paper are the chemical composition, structure, extraction, and purification of ulvan and Ulva oligosaccharides, where research progress on the biological activities of ulvan and Ulva oligosaccharides is summarized and prospected. A theoretical and practical basis has been provided for further research on ulvan and Ulva oligosaccharides, as well as the high-value development and effective utilization of marine algae resources. [ABSTRACT FROM AUTHOR]

Bacterial pathogens cause pain and death, add significantly to the expense of healthcare globally, and pose a serious concern in many aspects of daily life. Additionally, they raise significant issues in other industries, including pharmaceuticals, clothing, and food packaging. Due to their unique properties, a great deal of attention has been given to biogenic metal nanoparticles, nanocomposites, and their applications against pathogenic bacteria. This study is focused on biogenic silver and copper nanoparticles and their composites (UL/Ag2 O-NPS, Ul/CuO-NPs, and Ul/Ag/Cu-NCMs) produced by the marine green alga Ulva lactuca. The characterization of biogenic nanoparticles UL/Ag2 O-NPS and Ul/CuO-NPs and their composites Ul/Ag/Cu-NCMs has been accomplished by FT-IR, SEM, TEM, EDS, XRD, and the zeta potential. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) experiments were conducted to prove antibacterial activity against both Gram-positive and Gram-negative bacteria and anti-biofilm. The FTIR spectroscopy results indicate the exiting band at 1633 cm−1, which represents N–H stretching in nanocomposites, with a small shift in both copper and silver nanoparticles, which is responsible for the bio-reduction of nanoparticles. The TEM image reveals that the Ul/Ag/Cu-NCMs were hexagonal, and the size distribution ranged from 10 to 35 nm. Meanwhile, Ul/CuO-NPs are rod-shaped, whereas UL/Ag2 O-NPS are spherical. The EDX analysis shows that Cu metal was present in a high weight percentage over Ag in the case of bio-Ag/Cu-NCMs. The X-ray diffraction denotes that Ul/Ag/Cu-NCMs, UL/CuO-NPs, and UL/Ag2 O-NPS were crystalline. The results predicted by the zeta potential demonstrate that Ul/Ag/Cu-NCMs were more stable than Ul/CuO-NPs. The antibacterial activity of UL/Ag2 O-NPS, Ul/Ag/Cu-NCMs, and UL/CuO-NPs was studied against eleven Gram-negative and Gram-positive multidrug-resistant bacterial species. The maximum inhibition zones were obtained with UL/Ag2 O-NPS, followed by Ul/Ag/Cu-NCMs and Ul/CuO-NPs in all the tested bacteria. The maximum anti-biofilm percentage formed by E. coli KY856933 was obtained with UL/Ag2 O-NPS. These findings suggest that the synthesized nanoparticles might be a great alternative for use as an antibacterial agent against different multidrug-resistant bacterial strains. [ABSTRACT FROM AUTHOR]

Diabetes mellitus, a metabolic autoimmune disease caused by the consequences of expanding urbanization on lifestyle, is the third leading cause of death worldwide. However, unpleasant side effects and insufficient glucose control are drawbacks of contemporary diabetic treatment. Due to the undesirable side effects of the currently available antidiabetic drugs, the investigation for an effective natural-based antidiabetic therapy is essential to combating diabetes and its adverse effects. Algae are currently gaining popularity in the pharmaceutical and cosmetic sectors due to their ability to produce a wide range of bioactive compounds. Seaweed extracts have been shown to have promising bioactive molecules with anti-inflammatory, antioxidant, and hypoglycemic effects, making them suitable for the treatment of diabetes. The study aimed to provide valuable insights into the potential therapeutic benefits of marine green algae extracts in the management of diabetes in Alloxan-induced diabetic albino rats. The induction of diabetes in rats occurred intravenously administrated via a single dose of Alloxan at 150 mg/kg b. w. Then, rats were divided into four different groups: negative control group; diabetic control group; diabetic treated group receiving green algae crude extract and diabetic treated group receiving red algae crude extract. Data analysis of the biochemical investigations was performed using appropriate statistical methods to determine the significance of algae extract on diabetic animal models after 6 weeks of treatment. Preliminary results showed that the administration of seaweed (Green and Red Algae) extracts significantly reduced the hyperglycemic, hypercholesterolemia, and hyperlipidemia levels in diabetic-treated rats as compared to the diabetic untreated rats. Based on the above findings, the current research provided antidiabetic activity of marine algae against diabetes and its complications. [ABSTRACT FROM AUTHOR]

The green algal genus Ulva is one of the most widely distributed macroalgal genera. The taxonomy of Ulva is problematic due to its simple morphology. The study of the diversity of this genus has undergone great advances using molecular data, leading to changes in the taxonomic status of species, and the recognition of species complexes and cryptic species. Here we reassessed Ulva species from southeastern Brazil using molecular data. We recognized 10 taxa, among which only three previously reported species were confirmed by molecular data: U. compressa, U. lactuca and U. ohnoi, the latter recently recorded from insular waters in Fernando de Noronha Archipelago, northeastern Brazil. Our phylogenetic analyses and species delimitation methods strongly supported the establishment of Ulva kanagawae sp. nov. The species traditionally cited for southeastern Brazil, U. flexuosa, U. linza, U. rigida and U. paradoxa, proved to be misapplied names of U. tepida, U. aragoënsis, U. ohnoi/U. lactuca and U. torta, respectively. One taxon, Ulva sp., remains unnamed and needs further studies. Ulva chaugulei and U. tanneri, both considered here as cryptogenic species, are new occurrences for Brazil expanding their geographic distribution to the Atlantic Ocean and western Atlantic Ocean, respectively. In addition, our analysis of sequences from type materials revealed that U. pseudo-ohnoi is a heterotypic synonym of U. conglobata. This first systematic molecular study of Ulva species in Brazil points out that more extensive sampling is needed to reveal the true diversity of the genus in Brazilian waters. [ABSTRACT FROM AUTHOR]

Ulva rigida green seaweed is an abundant biomass consisting of polysaccharides and protein mixtures and a potential bioresource for bioplastic food packaging. This research prepared and characterized novel biodegradable films from Ulva rigida extracts. The water-soluble fraction of Ulva rigida was extracted and prepared into bioplastic films. 1H nuclear magnetic resonance indicated the presence of rhamnose, glucuronic and sulfate polysaccharides, while major amino acid components determined via high-performance liquid chromatography (HPLC) were aspartic acid, glutamic acid, alanine and glycine. Seaweed extracts were formulated with glycerol and triethyl citrate (20% and 30%) and prepared into films. Ulva rigida films showed non-homogeneous microstructures, as determined via scanning electron microscopy, due to immiscible crystalline component mixtures. X-ray diffraction also indicated modified crystalline morphology due to different plasticizers, while infrared spectra suggested interaction between plasticizers and Ulva rigida polymers via hydrogen bonding. The addition of glycerol decreased the glass transition temperature of the films from −36 °C for control films to −62 °C for films with 30% glycerol, indicating better plasticization. Water vapor and oxygen permeability were retained at up to 20% plasticizer content, and further addition of plasticizers increased the water permeability up to 6.5 g·mm/m2·day·KPa, while oxygen permeability decreased below 20 mL·mm/m2·day·atm when blending plasticizers at 30%. Adding glycerol efficiently improved tensile stress and strain by up to 4- and 3-fold, respectively. Glycerol-plasticized Ulva rigida extract films were produced as novel bio-based materials that supported sustainable food packaging. [ABSTRACT FROM AUTHOR]

Intensive agricultural practices and poor management of organic waste have adverse effects on aquatic ecosystems, where excessive macroalgal proliferation can occur to form 'green tides', with negative environmental, ecological and socioeconomic impacts. One novel method for converting a problematic material into a valuable resource is to use excess algal biomass as a feedstock for biochar production. With a high elemental composition, such a resource might be suitable to redress soil deficiencies and to ameliorate soil fertility. Green macroalgae from the Ulva genus, in bladed (predominantly U. rigida), tubular (predominantly U. prolifera) and mixed morphological (U. rigida and U. prolifera) phenotypes, were used to produce biochars. A pot trial within a controlled-environment chamber was carried out to determine the effects of amending high- and low-fertilizer compost with algal biochars (applied at 0, 0.5, 1, 2 and 5% w/w) on the growth rate of Arabidopsis thaliana. A commercial wood-based biochar was used under similar treatments as a control. Weekly imaging and final harvest weights provided additional growth data; composition data including ultimate and proximate analyses, pH, Brunauer–Emmett–Teller (BET) surface area and hydropyrolysis of the dried macroalgae and algal biochars were also conducted. Significant enhanced growth in seedlings grown with biochar amendment were not observed in high- or low-fertilizer compost, and the addition of algal biochars at 5% w/w to high-fertilizer soil significantly reduced plant growth. Elemental analysis revealed that the algal biochars contained high quantities of alkaline elements including sodium. It was hypothesised that salinity was the primary factor affecting plant growth at higher biochar application rates, despite the algae being sourced from an estuarine environment. Biochar provenance and composition is highly significant: using the catch-all term 'biochar' ignores both the range of materials and composition that could be used to create it and its subsequent impact within the soil. HIGHLIGHTS First plant trial using biochar predominantly from Ulva species. Negative impact seen with 5% algal biochar on plant growth. High sodium concentrations putatively identified as reduced plant growth cause. [ABSTRACT FROM AUTHOR]

A bioaccumulation study in red (Palmaria palmata) and green (Ulva sp.) seaweed has been carried out after exposure to different concentrations of citrate-coated titanium dioxide nanoparticles (5 and 25 nm) for 28 days. The concentration of total titanium and the number and size of accumulated nanoparticles in the seaweeds has been determined throughout the study by inductively coupled plasma mass spectrometry (ICP-MS) and single particle-ICP-MS (SP-ICP-MS), respectively. Ammonia was used as a reaction gas to minimize the effect of the interferences in the 48Ti determination by ICP-MS. Titanium concentrations measured in Ulva sp. were higher than those found in Palmaria palmata for the same exposure conditions. The maximum concentration of titanium (61.96 ± 15.49 μg g−1) was found in Ulva sp. after 28 days of exposure to 1.0 mg L−1 of 5 nm TiO2NPs. The concentration and sizes of TiO2NPs determined by SP-ICP-MS in alkaline seaweed extracts were similar for both seaweeds exposed to 5 and 25 nm TiO2NPs, which indicates that probably the element is accumulated in Ulva sp. mainly as ionic titanium or nanoparticles smaller than the limit of detection in size (27 nm). The implementation of TiO2NPs in Ulva sp. was confirmed by electron microscopy (TEM/STEM) in combination with energy dispersive X-Ray analysis (EDX). [ABSTRACT FROM AUTHOR]

Ulva rigida C. Agardh (sea lettuce) is a marine green alga. It grows naturally near shorelines in areas with freshwater influence. It can also be cultivated easily on farms and can be developed into many healthy food products, which bring in revenue for Thailand. It is important to develop an effective way to cultivate the alga. In this research, the molecular biology of sea lettuce using the tufA gene for the identification of Ulva genus and morphological characters at different culturing periods of U. rigida thallus were investigated using a light microscope (LM), a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The results revealed that the U. rigida alga consisted of various cell shapes including elliptic, irregular triangle, irregular quadrilateral, pentagonal and polygonal. The cell size increased with increasing periods of culture. However, when the alga was cultured for 28 days, the cell sizes were smaller than the original cells due to cell division during aging, resulting in an increase in cell numbers. U. rigida had grown rapidly in 14 days which was a relatively short period of cultivation. The results of this study indicate that U. rigida has a potential to be scaled up in pilot and commercial scales. [ABSTRACT FROM AUTHOR]

A sustainable biorefining and bioprocessing strategy was developed to produce edible-ulvan films and non-edible polyhydroxybutyrate films. The preparation of edible-ulvan films by crosslinking and plasticisation of ulvan with citric acid and xylitol was investigated using Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) analysis. The edible ulvan film was tested for its gut-friendliness using Lactobacillus and Bifidobacterium spp. (yoghurt) and was shown to improve these gut-friendly microbiome's growth and simultaneously retarding the activity of pathogens like Escherchia coli and Staphylococcus aureus. Green macroalgal biomass refused after the extraction of ulvan was biologically processed by dark fermentation to produce a maximum of 3.48 (± 0.14) g/L of volatile fatty acids (VFAs). Aerobic processing of these VFAs using Cupriavidus necator cells produced 1.59 (± 0.12) g/L of biomass with 18.2 wt% polyhydroxybutyrate. The present study demonstrated the possibility of producing edible and non-edible packaging films using green macroalgal biomass as the sustainable feedstock. Highlights: Novel bioprocess to produce edible and non-edible films from Ulva sp. was developed. Edible (ulvan) film was formed by citric acid crosslinking and xylitol plasticisation. Edible film boosted the growth of gut-friendly microbes and retarded pathogen growth. Dark fermentation was applied to produce volatile fatty acids using residual biomass. Polyhydroxyalkanoates were produced by Cupriavidus necator using volatile fatty acids. [ABSTRACT FROM AUTHOR]

Seaweed extracts are considered as marine biostimulants and have been successfully used in agriculture to improve the growth and tolerance to different environmental stress conditions of many crops. Therefore, the present study was carried out for the first time and aimed to determine the effects of a seaweed liquid extract on growth and photosynthetic performance as well as the water status of hydroponically-grown peppermint and purple basil plants. For this purpose, the experiment was conducted under greenhouse conditions and plants were cultivated in hydroponic systems according to the nutrient film technique. A seaweed liquid extract at 10% was prepared from the green marine macroalgae Ulva intestinalis and then added to the nutrient solution of the hydroponic system. Based on our experimental data, the main results have proven that Ulva intestinalis seaweed liquid extract could be successfully used as a biostimulant in the hydroponic cultivation of peppermint for its enhancing effect on some plant growth and photosynthetic as well as water status parameters. However, it is not recommended to add the seaweed liquid extract of Ulva intestinalis to the hydroponic culture of purple basil since most of the parameters analyzed were shown to be negatively affected by the seaweed liquid extract treatment. Furthermore, the results of this study could be practical for enhancing the production of medicinal and aromatic plants by adding the Ulva intestinalis seaweed liquid extract to the nutrient solution of the hydroponic system. [Display omitted] • A seaweed liquid extract was applied to hydroponically-grown peppermint and purple basil. • Plant growth is enhanced by adding the seaweed liquid extract in the nutrient solution. • Seaweed liquid extract could be successfully used as biostimulant in the hydroponic cultivation of peppermint. [ABSTRACT FROM AUTHOR]

In recent years, two types of macroalgae, namely, Ulva prolifera and Sargassumhorneri, have appeared occasionally together in the Yellow Sea and the East China Sea. Remote sensing enables timely and cost-effective observation of macroalgae across large areas. In the available studies, the recognition and classification of the two macroalgae are primarily based on spectral difference analysis. In this study, the spectral features, indices and textural feature parameters of the macroalgae targets were extracted and a preliminary multi-feature dataset was constructed based on Sentinel-2 images. Feature selection was performed using SHAP-based importance analysis and Bhattacharyya distance. From this, a multi-feature dataset was created and used as an input to a deep semantic segmentation network of improved ResUnet. The experiments of intelligent recognition and classification of U. prolifera and S. horneri were carried out using the proposed multi-feature-based ResUnet algorithm, with specific F1-scores of 96.7% and 96.8%, respectively. The proposed multi-feature-based ResUnet algorithm can obtain efficient and high-accuracy results for the recognition and classification of marine floating macroalgae. It achieves accurate remote sensing monitoring of the two types of marine floating macroalgae and has significant theoretical research significance and practical application value. [ABSTRACT FROM AUTHOR]

The increasing clinical and microbiological resistance of Candida species towards several commonly prescribed antifungal agents has stimulated the search for new active antifungal compounds from natural resources. The most important virulence factors of pathogenic Candida species are biofilm formation and hyphal development, making treatment very challenging due to the spread of resistant Candida isolates. This study was designed to explore the potential of different types of Ulva lactuca extracts on the growth of Candida spp., and evaluate the morphological alterations and time-kill as well. Methanol was the best solvent for extracting bioactive components from the examined algae Ulva lactuca (Chlorophyta) exhibiting the highest antifungal effect, followed by ethanol and chloroform. The minimum inhibition concentration (MIC) of U. lactuca methanol extract (ULME) was 62.5mg/ml, and the minimum fungicidal concentration (MFC) was 125mg/ml against all the tested oral Candida spp. Different concentrations of ULME (1xMIC, 2xMIC and 4xMIC) influenced the micromorphology of the tested oral Candida spp. and had an impact on biofilm formation. In the time-kill curves, ULME showed a concentration-dependent fungicidal effect. The cytotoxicity results showed that ULME has no significant toxic effects against normal human lung fibroblast cells (MRC-5 cell line). Moreover, the major phytochemical compounds were fatty acids, identified and quantified by using Gas Chromatography-Mass Spectrometry (GC/MS). In conclusion, ULME may be an alternative to conventional antifungal drugs for the treatment of oral candidiasis. [ABSTRACT FROM AUTHOR]

Introduction: Studies have shown that the macroalga Ulva lactuca is the largest CO2 receptor. In Cuba, the possibility of installing a plant for its intensive cultivation is being evaluated, which contributes to mitigate CO2 and allows obtaining algal biomass in a sustainable way. For design calculations, equipment selection and operating conditions, it is necessary to know the maximum biomass yieldand its photosynthetic equation. Objective: To estimate quantitatively the CO2 fixation mechanism of the macroalga Ulva lactuca, using different alternatives of the photosynthesis equation based on the calculation of stoichiometric coefficients. Materials and Methods: To calculate the yield and the amounts of substrate and nutrients that the biomass is able to assimilate, mass balances are carried out to optimize the production of algal biomass, applying the method of stoichiometric coefficients in the photosynthesis reaction. Results and Discussion: The maximum cell yield of Ulva lactuca is 63.5 %. Of the photosynthesis equations proposed, alternative four has values closer to photosynthetic reality, since there is a great correspondence between the stoichiometry of microalgae growth and product formation, together with the availability of nitrogen and phosphorus sources. Both results allow us to deduce the production of microalgal biomass to implement an economically and environmentally profitable technology. Conclusions: The maximum biomass yield and the photosynthetic equation allow for design calculations, equipment selection and operating conditions to scale up the technological process. [ABSTRACT FROM AUTHOR]

Green seaweeds exhibit a wide range of morphologies and occupy various ecological niches, spanning from freshwater to marine and terrestrial habitats. These organisms, which predominantly belong to the class Ulvophyceae, showcase a remarkable instance of parallel evolution toward complex multicellularity and macroscopic thalli in the Viridiplantae lineage. Within the green seaweeds, several Ulva species ("sea lettuce") are model organisms for studying carbon assimilation, interactions with bacteria, life cycle progression, and morphogenesis. Ulva species are also notorious for their fast growth and capacity to dominate nutrient‐rich, anthropogenically disturbed coastal ecosystems during "green tide" blooms. From an economic perspective, Ulva has garnered increasing attention as a promising feedstock for the production of food, feed, and biobased products, also as a means of removing excess nutrients from the environment. We propose that Ulva is poised to further develop as a model in green seaweed research. In this perspective, we focus explicitly on Ulva mutabilis/compressa as a model species and highlight the molecular data and tools that are currently available or in development. We discuss several areas that will benefit from future research or where exciting new developments have been reported in other Ulva species. [ABSTRACT FROM AUTHOR]

Background: Macroalgal epiphytic microbial communities constitute a rich resource for novel enzymes and compounds, but studies so far largely focused on tag-based microbial diversity analyses or limited metagenome sequencing of single macroalgal species. Results: We sampled epiphytic bacteria from specimens of Ulva sp. (green algae), Saccharina sp. (brown algae), Grateloupia sp. and Gelidium sp. (both red algae) together with seawater and sediment controls from a coastal reef in Weihai, China, during all seasons. Using 16S rRNA amplicon sequencing, we identified 14 core genera (consistently present on all macroalgae), and 14 dominant genera (consistently present on three of the macroalgae). Core genera represented ~ 0.7% of all genera, yet accounted for on average 51.1% of the bacterial abundances. Plate cultivation from all samples yielded 5,527 strains (macroalgae: 4,426) representing 1,235 species (685 potentially novel). Sequencing of selected strains yielded 820 non-redundant draft genomes (506 potentially novel), and sequencing of 23 sampled metagenomes yielded 1,619 metagenome-assembled genomes (MAGs), representing further 1,183 non-redundant genomes. 230 isolates and 153 genomes were obtained from the 28 core/dominant genera. We analyzed the genomic potential of phycosphere bacteria to degrade algal polysaccharides and to produce bioactive secondary metabolites. We predicted 4,451 polysaccharide utilization loci (PULs) and 8,810 biosynthetic gene clusters (BGCs). These were particularly prevalent in core/dominant genera. Conclusions: Our metabolic annotations and analyses of MAGs and genomes provide new insights into novel species of phycosphere bacteria and their ecological niches for an improved understanding of the macroalgal phycosphere microbiome. DnRc39z963CYrL7RdN5UNd Video Abstract [ABSTRACT FROM AUTHOR]

Ulva sp. is green macroalgae with a high potential for nutrient-dense food production. This species is found on a coastline in the intertidal zone of Indonesia's waters. There has been research on this species starting from post-harvest handling, nutrition, probiotics, and its ulvaran, however, information on the effect of temperature storage on Ulva lactuca freshness is still lacking. This study was undergone to evaluate the freshness quality of U. lactuca by sensory changes in different temperatures short-term storage. In order to evaluate the effect of the different storage circumstances, the fresh U. lactuca was collected from its natural habitat (intertidal zone of Sepanjang Coast, Yogyakarta Indonesia). It was rinsed from debris and epiphyte, stored in a transparent polyethylene bag, and stored at 4 °C, 15-20 °C, and room temperature for five days. Color, pH, ash, moisture, crude protein, chlorophyll, Total Plate Count, and sensory analysis was undergone during the storage period. The sensory evaluation score of U. lactuca in 4 °C was more than 6, and better than other storages. The crude protein (U. lactuca stored in 4 °C) decreased significantly on day 4 by 5.53%, it was lower than others. The TPC of all samples varied from 147x103in 0 days of storage to 2,462.5x103 CFU/ml on the last day of storage. In summary, the sensory scores of U. lactuca are more consistent and higher at 4 °C than in other storage conditions, despite a slight decline in nutrient content. [ABSTRACT FROM AUTHOR]

To understand the evolutionary driving forces of chloroplast (or plastid) genomes (plastomes) in the green macroalgal genus Ulva (Ulvophyceae, Chlorophyta), in this study, we sequenced and constructed seven complete chloroplast genomes from five Ulva species, and conducted comparative genomic analysis of Ulva plastomes in Ulvophyceae. Ulva plastome evolution reflects the strong selection pressure driving the compactness of genome organization and the decrease of overall GC composition. The overall plastome sequences including canonical genes, introns, derived foreign sequences and non-coding regions show a synergetic decrease in GC content at varying degrees. Fast degeneration of plastome sequences including non-core genes (minD and trnR3), derived foreign sequences, and noncoding spacer regions was accompanied by the marked decrease of their GC composition. Plastome introns preferentially resided in conserved housekeeping genes with high GC content and long length, as might be related to high GC content of target site sequences recognized by intronencoded proteins (IEPs), and to more target sites contained by long GC-rich genes. Many foreign DNA sequences integrated into different intergenic regions contain some homologous specific orfs with high similarity, indicating that they could have been derived from the same origin. The invasion of foreign sequences seems to be an important driving force for plastome rearrangement in these IRlacking Ulva cpDNAs. Gene partitioning pattern has changed and distribution range of gene clusters has expanded after the loss of IR, indicating that genome rearrangement was more extensive and more frequent in Ulva plastomes, which was markedly different from that in IR-containing ulvophycean plastomes. These new insights greatly enhance our understanding of plastome evolution in ecologically important Ulva seaweeds. [ABSTRACT FROM AUTHOR]

Marine algae are considered a source of different bioactive constituents including protein, oil, fiber, vitamins, pigments and dietary minerals. To evaluate the fine chemical and biochemical properties of the marine microalga Nannochloropsis oculata and macroalga Ulva lactuca, the present study was carried out. The cultivated N. oculate and the collected U. lactuca were washed, oven-dried, ground and subjected to analysis of moisture, protein, fats, carbohydrates and ash. In addition, macro and micro-nutrients, amino acids profile, fatty acids methyl ester and pigments were assessed. The moisture content of U. lactuca was higher (13.25 %) than N. oculata (3.5 %). Protein, oil and fiber contents were significantly higher (P<0.05) in N. oculata than in U. lactuca and ranged between 32.19 % and 20.44 %, 10.29 % and 0.65 %, 11.91 % and 8.61 %, respectively, based on dry weight. Total phytochemical chlorophyll in U. lactuca (5.97µg/ml) was more than in N. oculata (1.18µg/ml). The dominant dietary element in N. oculata was P (24000 mg/kg), while Ca (48300 mg/kg) was dominant in U. lactuca. The trace dietary minerals (Fe, Mn and Cu) were significantly higher in U. lactuca than in N. oculata. Both algae proteins had 17 (N. oculata) and 16 (U. lactuca) amino acids, seven of them being non-essential amino acids, which accounted for 40.01 and 48.75 g/100g, respectively. Saturated and unsaturated fatty acids represented 45.13 and 54.87%; 68.95 and 31.05% of the fat of N. oculata and U. lactuca, respectively. Polyunsaturated fatty acids were more evident in N. oculata (31.36%) than in U. lactuca (3.81%). [ABSTRACT FROM AUTHOR]

Detecting non-native species can be challenging, particularly in the case of taxa such as seaweeds, which can be difficult to distinguish based on morphology and often require molecular-assisted taxonomy for reliable identification. The sub-Antarctic island of South Georgia supports unique and important marine biodiversity, including a rich seaweed flora, but despite its isolation, its inshore ecosystems are susceptible to the introduction of potentially invasive non-native species. Here, we provide the first report of a non-native seaweed in South Georgia, Ulva fenestrata Postels & Ruprecht (Ulvophyceae, Chlorophyta), and confirm its widespread presence in the Falkland Islands via molecular-assisted taxonomy. Phylogenetic analyses of tufA and rbcL-3P genetic markers enabled the identification of a specimen collected from Grytviken, South Georgia in November 2021 as U. fenestrata. In terms of tufA sequence, this sample was identical to specimens collected from four sites spanning West and East Falkland in 2013 and 2018. This study represents the second Southern Hemisphere record of U. fenestrata, which is generally regarded as a Northern Hemisphere species. Our findings provide a foundation for monitoring this potentially invasive species in South Georgia, and for determining its likely source and mode of arrival, while emphasising the importance of robust biosecurity measures. [ABSTRACT FROM AUTHOR]

SUMMARY: The subtidal brown algal species Sporochnus dotyi Brostoff (Sporochnales, Phaeophyceae), which has been regarded as a Hawaiian endemic, is reported from Kushimoto, Kii Peninsula, Pacific coast of central Honshu, Japan, for the first time outside Hawai'i. The species grew on subtidal rocks ca. 5–20 m deep attached by a small conical holdfast. The erect thalli were 5–30 cm high, terete, robust and alternately branched in 1–2 orders. When mature, pedicellate receptacles developed on the branches, and formed elliptical sori 1 mm long with a pedicel 3–5 mm long. The apical parts of the thalli and the receptacles were terminated with a tuft of simple assimilatory filaments of up to 4 mm long and showed prominent green to yellow underwater iridescence. Reproductive filaments (paraphyses) were densely packed, simple, up to 200 μm long and bore 4–6 mostly unilateral unilocular zoidangia 20–22 μm long and 5–6 m in diameter. In the genetic analyses, the Sporochnus alga from Kushimoto had partial rbcL sequence identical to S. dotyi from Hawai'i. The cox3 phylogeny revealed that this alga formed a fully supported clade with S. dotyi. Therefore, we identified the alga from Kushimoto as S. dotyi. This finding of S. dotyi from Japan, together with the recent reports of the mesophotic macroalgae Ryuguphycus kuaweuweu (=Umbraulva kuaweuweu), Ulva iliohaha and Newhousia imbricata from various localities in the Pacific Ocean including Japan, suggest closer biogeographical connections of subtidal/mesophotic macroalgae in the Pacific than previously recognized. [ABSTRACT FROM AUTHOR]