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Leishmaniasis in Africa, which has been designated as a priority neglected tropical disease by various global organizations, exerts its impact on millions of individuals, primarily concentrated within this particular region of the world. As a result of the progressively grave epidemiological data, numerous governmental sectors and civil organizations have concentrated their endeavors on this widespread outbreak with the objective of devising appropriate remedies. This comprehensive examination delves into multiple facets of this parasitic ailment, scrutinizing the associated perils, diagnostic intricacies, and deficiencies within the existing therapeutic protocols. Despite the established efficacy of current treatments, they are not immune to deleterious incidents, particularly concerning toxicity and the emergence of parasitic resistance, thus accentuating the necessity of exploring alternative avenues. Consequently, this research not only encompasses conventional therapeutic approaches, but also extends its scope to encompass complementary and alternative medicinal techniques, thereby striving to identify innovative solutions. A particularly auspicious dimension of this study lies in the exploration of natural substances and by-products derived from some brown algae of the Sargassaceae family. These resources possess the potential to assume a pivotal role in the management of leishmaniasis. [ABSTRACT FROM AUTHOR]

Sargassaceae, the most abundant family in Fucales, was recently formed through the merging of the two former families Sargassaceae and Cystoseiraceae. It is widely distributed in the world's oceans, notably in tropical coastal regions, with the exception of the coasts of Antarctica and South America. Numerous bioactivities have been discovered through investigations of the chemical diversity of the Sargassaceae family. The secondary metabolites with unique structures found in this family have been classified as terpenoids, phlorotannins, and steroids, among others. These compounds have exhibited potent pharmacological activities. This review describes the new discovered compounds from Sargassaceae species and their associated bioactivities, citing 136 references covering from March 1975 to August 2023. [ABSTRACT FROM AUTHOR]

The diversity of the brown algal genus Sargassum C.Agardh in the Philippines is the highest in the tropical western Pacific Ocean. However, most studies on Philippine Sargassum are based on morphoanatomies and the assumption that the genus is very diverse in the country has never been tested based on molecular information. Considering that many Sargassum species are highly polymorphic and the recent advance on Sargassum systematics facilitated by molecular phylogenetic studies, we believe that the species of Sargassum from the Philippines should now be reassessed with the tools of molecular taxonomy. We present here the results of our molecular-assisted taxonomic studies on the Sargassum of the northern Philippines, particularly along the coasts of four coastal provinces in northwestern Luzon (i.e., Ilocos Norte, Ilocos Sur, La Union, and Pangasinan). We recognized three distinct species lineages, namely, Sargassum aquifolium (Turner) C.Agardh, Sargassum ilicifolium (Turner) C.Agardh, and Sargassum polycystum C.Agardh based on our molecular analyses of 74 specimens from our study areas. Our morphological observations on the range of characters of these species also suggest that several common Sargassum taxa in the Philippines have been misidentified. Particularly, specimens previously attributed to S. kushimotense Yendo should be referred as S. aquifolium while the widely distributed and highly plastic S. ilicifolium is often confused and identified in the Philippines under several names including S. crassifolium J.Agardh, S. cristaefolium C.Agardh, and S. turbinarioides Grunow. Taken together, our results suggest that Sargassum biodiversity in the Philippines may have been inflated by misidentifications, and, that species diversity is actually much lower than initially thought. Étude des Sargassum (Fucales, Phaeophyceae) dans le nord-ouest de Luzon, Philippines au moyen des outils de la taxonomie moléculaire. La diversité du genre d'algues brunes Sargassum C.Agardh aux Philippines est la plus élevée de l'océan Pacifique tropical occidental. Cependant, la plupart des études sur les Sargassum des Philippines sont basées sur de la morpho-anatomie, et l'hypothèse selon laquelle le genre est très diversifié dans le pays n'a jamais été vérifiée sur la base d'informations moléculaires. Étant donné que de nombreuses espèces de Sargassum sont hautement polymorphiques et que les études phylogénétiques moléculaires ont récemment permis de faire progresser la systématique, nous pensons que les espèces de Sargassum des Philippines devraient maintenant être réévaluées au moyen d'outils de la taxonomie moléculaire. Nous présentons ici les résultats de nos études taxonomiques moléculaires sur les sargasses du nord des Philippines, en particulier le long des côtes de quatre provinces côtières du nord-ouest de Luzon (Ilocos Norte, Ilocos Sur, La Union et Pangasinan). Nous avons reconnu trois lignées d'espèces distinctes, à savoir Sargassum aquifolium (Turner) C.Agardh, Sargassum ilicifolium (Turner) C.Agardh, et Sargassum polycystum C.Agardh, sur la base d'analyses moléculaires de 74 spécimens provenant de nos zones d'étude. Nos observations morphologiques sur la gamme de caractères de ces espèces suggèrent également que plusieurs taxons communs de Sargassum aux Philippines ont été mal identifiés. En particulier, les spécimens précédemment attribués à S. kushimotense Yendo devraient être appelés S. aquifolium, tandis que S. ilicifolium, largement répandue et très plastique, est souvent confondue et identifiée aux Philippines sous plusieurs noms, dont S. crassifolium J.Agardh, S. cristaefolium C.Agardh et S. turbinarioides Grunow. Nos résultats suggèrent que la biodiversité des sargasses aux Philippines pourrait avoir été gonflée par des erreurs d'identification et que la diversité des espèces est en fait beaucoup plus faible qu'on ne le pensait initialement. [ABSTRACT FROM AUTHOR]

Leishmaniasis in Africa, which has been designated as a priority neglected tropical disease by various global organizations, exerts its impact on millions of individuals, primarily concentrated within this particular region of the world. As a result of the progressively grave epidemiological data, numerous governmental sectors and civil organizations have concentrated their endeavors on this widespread outbreak with the objective of devising appropriate remedies. This comprehensive examination delves into multiple facets of this parasitic ailment, scrutinizing the associated perils, diagnostic intricacies, and deficiencies within the existing therapeutic protocols. Despite the established efficacy of current treatments, they are not immune to deleterious incidents, particularly concerning toxicity and the emergence of parasitic resistance, thus accentuating the necessity of exploring alternative avenues. Consequently, this research not only encompasses conventional therapeutic approaches, but also extends its scope to encompass complementary and alternative medicinal techniques, thereby striving to identify innovative solutions. A particularly auspicious dimension of this study lies in the exploration of natural substances and by-products derived from some brown algae of the Sargassaceae family. These resources possess the potential to assume a pivotal role in the management of leishmaniasis.

Cystoseira sensu lato (s.l.) – encompassing the genera Cystoseira sensu stricto (s.s.), Ericaria and Gongolaria – is a diverse group of forest-forming brown macroalgae endemic to the warm-temperate North-east Atlantic. These algae have immense biogeographic and ecological significance and have been experiencing recent regional declines. Most Cystoseira s.l. display important morphological plasticity and can be confused with similar species. Therefore, species boundaries, geographic ranges and phylogenetic affinities remain imprecise for most. In the face of persistent taxonomic difficulties, several authors underlined the necessity for new molecular-based approaches, but studies so far lacked representativity, resolution and standardization. To fill in these gaps, in this study we sequenced a comprehensive collection of Cystoseira s.l. spanning its entire North-east Atlantic range for a ~1200 bp cox1 barcode, and sequenced selected individuals representing major genetic entities for a few additional plastid markers. Phylogeographic, phylogenetic and species delimitation methods revealed 27 Molecular Operational Taxonomic Units, including unaccounted cryptic diversity, and elucidated with unprecedented resolution species compositions and phylogenetic relationships within each genus. Some entities within the lineages Cystoseira compressa/humilis, Ericaria brachycarpa/crinita, E. selaginoides and tophulose Gongolaria, as well as among free-living algae, conflicted with a priori taxonomic assignments, and required the redefinition, reinstatement and recognition of new taxa. For some, diagnostic mutations and biogeography were more useful for species identifications than morphological characters or conventional barcoding gaps. A few species showed narrow geographic ranges and others were the sole representatives of their respective lineages. Several sister-species showed Atlantic vs Mediterranean complementary ranges. Phylogenetic signal of cox1 was nevertheless insufficient to confidently determine patterns of lineage splitting in several lineages and species complexes and did not improve significantly with additional plastid markers. We discuss novel systematics and biogeography insights considering the advantages and shortcomings of the barcoding approach employed, and how this comprehensive baseline study can be expanded to address multiple questions still left unanswered. HIGHLIGHTS Identification of major genetic entities of Cystoseira s.s., Ericaria and Gongolaria. A comprehensive reference cox1 barcode library for Cystoseira s.l. Updated systematics and biogeography of Cystoseira s.l. [ABSTRACT FROM AUTHOR]

Sargassaceae, the most abundant family in Fucales, was recently formed through the merging of the two former families Sargassaceae and Cystoseiraceae. It is widely distributed in the world’s oceans, notably in tropical coastal regions, with the exception of the coasts of Antarctica and South America. Numerous bioactivities have been discovered through investigations of the chemical diversity of the Sargassaceae family. The secondary metabolites with unique structures found in this family have been classified as terpenoids, phlorotannins, and steroids, among others. These compounds have exhibited potent pharmacological activities. This review describes the new discovered compounds from Sargassaceae species and their associated bioactivities, citing 136 references covering from March 1975 to August 2023.

Cystophora is the second largest genus of fucoids worldwide and, like many other forest‐forming macroalgae, is increasingly threatened by a range of anthropogenic impacts including ocean warming. Yet, limited ecological information is available from the warm portion of their range (SW Western Australia), where severe range contractions are predicted to occur. Here, we provide the first insights on the abundance, diversity, productivity, and stand structure of Cystophora forests in this region. Forests were ubiquitous over more than 800 km of coastline and dominated sheltered and moderately‐exposed reefs. Stand biomass and productivity were similar or greater than that of kelp forests in the temperate reef communities examined, suggesting that Cystophora spp. play a similarly important ecological role. The stand structure of Cystophora forests was, however, different than those of kelp forests, with most stands featuring an abundant bank of sub‐canopy juveniles and only a few plants forming the canopy layer. Stand productivity followed an opposite seasonal pattern than that of kelps, with maximal growth in late autumn through early winter and net biomass loss in summer. Annually, stands contributed between 2.2 and 5.7 kg · m−2 (fresh biomass) to reef productivity depending on the dominant stand species. We propose that Cystophora forests play an important and unique role in supporting subtidal temperate diversity and productivity throughout temperate Australia, and urge a better understanding of their ecology and responses to anthropogenic threats. [ABSTRACT FROM AUTHOR]

Fucales are an order within the Phaeophyceae that include most of the common littoral seaweeds in temperate and subtropical coastal regions. Many species of this order have long been a part of human culture with applications as food, feedand remedies in folk medicine. Apart from their high nutritional value, these seaweeds are also a well-known reservoir of multiple bioactive compounds with great industrial interest. Among them, phlorotannins, a unique and diverse class of brown algae-exclusive phenolics, have gathered much attention during the last few years due to their numerous potential health benefits. However, due to their complex structural features, combined with the scarcity of standards, it poses a great challenge to the identification and characterization of these compounds, at least with the technology currently available. Nevertheless, much effort has been taken towards the elucidation of the structural features of phlorotannins, which have resulted in relevant insights into the chemistry of these compounds. In this context, this review addresses the major contributions and technological advances in the field of phlorotannins extraction and characterization, with a particular focus on Fucales. [ABSTRACT FROM AUTHOR]

Chemical analysis of the organic extract from intertidal brown seaweed Sargassum ilicifolium (family Sargassaceae) characterised an undescribed xenicane-type diterpenoid sargilicixenicane, elucidated as 3-(17-hydroxy-14-methylhept-13-en-10-yl)-6-methylhexahydro-1H-cyclonona[c]furan-4,19-diyl diacetate (compound 1). The studied compound exhibited prospective free radical quenching potential (IC50 1.2-1.4 mM) in comparison with commercial antioxidant (α-tocopherol, IC50 > 1.40 mM). Attenuation property of sargilicixenicane against pro-inflammatory enzyme, 5-lipoxygenase (IC50 4.70 mM) was comparable with that displayed by the non-steroidal anti-inflammatory agent ibuprofen (IC50 4.51 mM). Greater selectivity index displayed by the studied xenicane-type diterpenoid (1.42) than that exhibited by ibuprofen (0.44) recognised the selective attenuation potential of the former against the inducible cyclooxygenase-2 and 5-lipoxygenase enzymes. Higher electronic parameters (topological polar surface area, 82.06) and balanced hydrophobic-hydrophilic property (octanol-water partition coefficient 2.94) coupled with docking score (-11.17 kcal mol−1) and lower binding energy (-9.61 kcal mol−1) with the active site of 5-lipoxygenase supported the significant anti-inflammatory properties of the studied xenicane-type diterpenoid. [ABSTRACT FROM AUTHOR]

The Genus Turbinaria is still chemically and pharmacologically underexplored. These brown algae belong to the family Sargassaceae. Therapeutic potentials of pure compounds isolated from the Genus Turbinaria are extraordinarily promising as antiproliferative, antipyretic, anti-inflammatory immunostimulatory, anti-diabetic, anti-obesity, antiviral, antimicrobial, cardioprotective, hepatoprotective and hypolipidemic. Those activities are represented by diverse classes of compounds including sterols, amino acids, fatty acids, alcohols, halocarbons, hydrocarbons, carbohydrates, esters and cyclic tetrapyrrole compounds. This review focuses on the Genus Turbinaria during the period 1972 to 2019. [ABSTRACT FROM AUTHOR]

Sargassum is one of the most important genera of the family Sargassaceae in brown algae and is used to produce carrageenan, mannitol, iodine, and other economic substances. Here, seven complete plastid genomes of Sargassum ilicifolium var. conduplicatum, S. graminifolium, S. phyllocystum, S. muticum, S. feldmannii, S. mcclurei , and S. henslowianum were assembled using next-generation sequencing. The sizes of the seven circular genomes ranged from 124,258 to 124,563 bp, with two inverted regions and the same set of plastid genes, including 139 protein-coding genes (PCGs), 28 transfer (t)RNAs, and 6 ribosomal (r)RNAs. Compared with the other five available plastid genomes of Fucales, 136 PCGs were conserved, with two common ones shared with Coccophora langsdorfii , and one with S. fusiforme and S. horneri. The co-linear analysis identified two inversions of trnC(gca) and trnN(gtt) in ten Sargassum species, against S. horneri and C. langsdorfii. The phylogenetic analysis based on the plastid genomes of 55 brown algae (Phaeophyceae) showed four clades, whose ancient ancestor lived around 201.42 million years ago (Mya), and the internal evolutionary branches in Fucales started to be formed 92.52 Mya, while Sargassum species were divided into two subclades 14.33 Mya. Our novel plastid genomes provided evidence for the speciation of brown algae and plastid genomic evolution events. [ABSTRACT FROM AUTHOR]

Turbinaria ornata is a species of marine brown seaweed and in the family sargassaceae. They were freshly collected from Mandapam Coastal Area, Rameswaram Tamilnadu, India and rinsed in seawater and packed in sterile bags for further proceedings to laboratory. Seaweeds are possible renewable resources in the marine environment. It has been used as antioxidant and antimutagen. Ethanol extract was prepared for further analysis. GCMS analysis of ethanol extract of Turbinaria ornata was performed using a Shimadzu 2010 plus comprising an AOC-20i auto sampler and gas chromatograph interfaced to a mass spectrometer. The GCMS analysis reveals that many bioactive compounds such as 6- octadecenoic acid, 9,12-octadecadienoic acid, Bis (2-ethylhexyl) phthalate, oleic acid presents in the extract of Turbinaria ornata. The above bioactive compounds were taken for molecular docking studies to improve the reliability, accuracy of biological test and show the possible interactions between molecules and their target receptors. So, in this present study in silico molecules docking was carried out to analyze the binding properties of 6-octadecenoic acid, 9,12-octadecadienoic acid, Bis (2-ethylhexyl) phthalate, oleic acid against standard liver cancer drug such as Doxorubicin to target protein βcatenin (1JPW). The results show the better binding interactions and suppression activity of bioactive compounds. [ABSTRACT FROM AUTHOR]

In this paper, a new species of the Cystoseira complex from Porto Palo di Capo Passero (Sicily, Italy) is described. The species, which shows the same characters as Cystoseira hyblaea Giaccone as described by Giaccone (1986) and Bouafif et al. (2016), from its morpho-anatomical characters, is assigned to the genus Ericaria Stackhouse. Because of "Cystoseira hyblaea" was not validly published name, Ericaria giacconei sp. nov. is here described. The main characteristics of the species are: 1) a caespitose habit; 2) large axes rugged with apices smooth, not prominent; 3) vegetative branches without spinose appendages; 4) primary branches with a cupressoid outline, especially when they are fertile; and 5) receptacles terminal, compact, cylindrical-oval, verrucose, with deciduous spinose appendages. Ericaria giacconei sp. nov. is related to both E. crinita (Duby) Molinari & Guiry and E. barbatula (Kützing) Molinari & Guiry, but it differs from them mainly in the basal system consisting of a robust and compact basal disc and in apex of cauloids smooth and not prominent, never surrounded by spiniform appendages. A critical re-examination of herbarium specimens from Isola delle Correnti (eastern Sicily, Italy) attributed to E. crinita (as C. crinita) demonstrated that they actually belong to our new species. [ABSTRACT FROM AUTHOR]

Sargassum is one of the most important genera of the family Sargassaceae in brown algae and is used to produce carrageenan, mannitol, iodine, and other economic substances. Here, seven complete plastid genomes of Sargassum ilicifolium var. conduplicatum, S. graminifolium, S. phyllocystum, S. muticum, S. feldmannii, S. mcclurei, and S. henslowianum were assembled using next-generation sequencing. The sizes of the seven circular genomes ranged from 124,258 to 124,563 bp, with two inverted regions and the same set of plastid genes, including 139 protein-coding genes (PCGs), 28 transfer (t)RNAs, and 6 ribosomal (r)RNAs. Compared with the other five available plastid genomes of Fucales, 136 PCGs were conserved, with two common ones shared with Coccophora langsdorfii, and one with S. fusiforme and S. horneri. The co-linear analysis identified two inversions of trnC(gca) and trnN(gtt) in ten Sargassum species, against S. horneri and C. langsdorfii. The phylogenetic analysis based on the plastid genomes of 55 brown algae (Phaeophyceae) showed four clades, whose ancient ancestor lived around 201.42 million years ago (Mya), and the internal evolutionary branches in Fucales started to be formed 92.52 Mya, while Sargassum species were divided into two subclades 14.33 Mya. Our novel plastid genomes provided evidence for the speciation of brown algae and plastid genomic evolution events.

Fucales are an order within the Phaeophyceae that include most of the common littoral seaweeds in temperate and subtropical coastal regions. Many species of this order have long been a part of human culture with applications as food, feedand remedies in folk medicine. Apart from their high nutritional value, these seaweeds are also a well-known reservoir of multiple bioactive compounds with great industrial interest. Among them, phlorotannins, a unique and diverse class of brown algae-exclusive phenolics, have gathered much attention during the last few years due to their numerous potential health benefits. However, due to their complex structural features, combined with the scarcity of standards, it poses a great challenge to the identification and characterization of these compounds, at least with the technology currently available. Nevertheless, much effort has been taken towards the elucidation of the structural features of phlorotannins, which have resulted in relevant insights into the chemistry of these compounds. In this context, this review addresses the major contributions and technological advances in the field of phlorotannins extraction and characterization, with a particular focus on Fucales.

Chemical investigation of Phaeophytan marine macroalga Turbinaria ornata (family Sargassaceae) resulted in the characterization of three 2-furanone analogues, which were characterized as 6, 7-dihydroxy-8-methyl-3-(5′-methyloct-4′-en-1′-yl)-hexahydrocyclooct-1-en-[1, 2-c]furan-11-one (turbinafuranone A), 4-hydroxy-3-isopropyl-7, 8-dimethyl-6-(pentan-2′-acetate)-hexahydrocycloocta-1-en-[1, 2-c]furan-11-one (turbinafuranone B), and 6-acetoxy-8-ethyl-5-methoxy-3-(2′-methylhex-4′-en-1′-yl)-pentahydrocycloocta-1, 7-dien-[1, 2-c]furan-11-one (turbinafuranone C). Inhibitory property of turbinafuranone B against tyrosine phosphatase-1B was significantly greater (IC50 2.42 mM) than standard agent sodium metavanadate (IC50 2.52 mM). Greater electronic properties along with molecular docking experiments corroborated the attenuation property of turbinafuranone B against protein tyrosine phosphatase-1B, by exhibiting minimum binding energy of −11.80 kcal/mol compared to other studied analogues. The results demonstrated that the undescribed turbinafuranone B might be used as prospective natural anti-hyperglycemic lead to alleviate the likelihood of higher postprandial blood glucose levels. [ABSTRACT FROM AUTHOR]

Cystoseira sensu lato (Class Phaeophyceae, Order Fucales, Family Sargassaceae) forests play a central role in marine Mediterranean ecosystems. Over the last decades, Cystoseira s.l. suffered from a severe loss as a result of multiple anthropogenic stressors. In particular, Gongolaria barbata has faced multiple human-induced threats, and, despite its ecological importance in structuring rocky communities and hosting a large number of species, the natural recovery of G. barbata depleted populations is uncertain. Here, we used nine microsatellite loci specifically developed for G. barbata to assess the genetic diversity of this species and its genetic connectivity among fifteen sites located in the Ionian, the Adriatic and the Black Seas. In line with strong and significant heterozygosity deficiencies across loci, likely explained by Wahlund effect, high genetic structure was observed among the three seas (ENA corrected FST = 0.355, IC = [0.283, 0.440]), with an estimated dispersal distance per generation smaller than 600 m, both in the Adriatic and Black Sea. This strong genetic structure likely results from restricted gene flow driven by geographic distances and limited dispersal abilities, along with genetic drift within isolated populations. The presence of genetically disconnected populations at small spatial scales (< 10 km) has important implications for the identification of relevant conservation and management measures for G. barbata: each population should be considered as separated evolutionary units with dedicated conservation efforts. [ABSTRACT FROM AUTHOR]

The brown alga, Sargassum natans, forms groups of pelagic thalli, and is also found in the macroalgae barrages that eventually occur in the Caribbean region. In this work, a new species for the phycological flora of Venezuela is reported, with contributions to the description of some vegetative structures of a population of S. natans found in the sector La Caracola of Moreno Beach, Margarita Island, during the month of April 2018. Three specimens were collected and preserved in 4% formaldehyde. The analysis of the vegetative structures by means of a stereoscopic microscope, revealed the presence of densely divided lateral branches with abundant pneumatophores that presented acicular appendages or a phyllodes-like projection, and the absence of lateral wings on their pedicels, the phylloids with toothed edges and few or no cryptostomes on the sheets, which allowed the identification of the specie as Sargassum natans (Linnaeus) Gaillon, belonging to the family Sargassaceae Kutzing. This species had not been recorded in the marinecoastal zone of Venezuela, so its distribution is expanded in the Caribbean Sea. [ABSTRACT FROM AUTHOR]

SUMMARY We investigated the monthly variations of estimated in‐situ uptake and growth‐related demand for phosphorus in Sargassum macrocarpum during a growth period from December 2017 to April 2018, a maturation period from May to August 2018, and the second‐growth period from September 2018 to January 2019. Phosphate uptake was relatively low during maturation and high during growth, and coincided with changes in external phosphate levels. The demand for phosphorus was at its highest in March 2018, which corresponded with the highest growth rate and tissue phosphorus levels. Thereafter, the demand was relatively constant between April 2018 and January 2019. Consequently, the uptake rate exceeded demand from December 2017 to February 2018 and December 2018 to January 2019, suggesting that phosphorus accumulated in tissues. Additionally, the uptake rates between March 2018 and November 2018 were 0.1–0.8 times lower than the demand, probably resulting in the effective use of stored phosphorus to sustain growth during this phosphate‐depleted period. The variations between estimated uptake and demands for P found in S. macrocarpum indicate that P dynamics vary with life stage and are implicitly linked to the season. [ABSTRACT FROM AUTHOR]

SUMMARY: The effects of irradiance, temperature, thermal‐ and chilling‐light sensitivities on the photosynthesis of a temperate alga, Sargassum macrocarpum (Fucales) were determined by a pulse amplitude modulation (PAM)‐chlorophyll fluorometer and dissolved oxygen sensors. Oxygenic photosynthesis–irradiance curves at 8, 20, and 28°C revealed that the maximum net photosynthetic rates (NPmax) and saturation irradiance were highest at 28°C, and lowest at 8°C. Gross photosynthesis and dark respiration determined over a range of temperatures (8–36°C) at 300 μmol photons m−2 s−1 revealed that the maximum gross photosynthetic rate (GPmax) occurred at 27.8°C, which is consistent with the highest seawater temperature in the southern distributional limit of this species in Japan. Additionally, the maximum quantum yields of photosystem II (Fv/Fm) during the 72‐h temperature exposures were stable at 8–28°C, but suddenly dropped to zero at higher temperatures, indicative of PSII deactivation. Continuous exposure (12 h) to irradiance of 200 (low) and 1000 (high) μmol photons m−2 s−1 at 8, 20, and 28°C revealed greater declines in their effective quantum yields (ΦPSII) under high irradiance. While ΦPSII under low irradiance were very similar with the initial Fv/Fm under 20 and 28°C, values rapidly decreased with exposure duration at 8°C. At this temperature, Fv/Fm did not recover to initial values even after 12 h of dark acclimation. Final Fv/Fm of alga at 28°C under high irradiance treatment also did not recover, suggesting its sensitivity to photoinhibition at both low and high temperatures. These photosynthetic characteristics reflect both the adaptation of the species to the general environmental conditions, and its ability to acclimate to seasonal changes in seawater temperature within their geographical range of distribution. [ABSTRACT FROM AUTHOR]

Sargassum vachellianum is an ecologically important brown alga. It is China-specific and mainly inhabits in rocky intertidal zones in southeast coastal waters of China. In this study, we sequenced its circular complete chloroplast genome (cpDNA) and compared it with cpDNAs from S. vachellianum, S. horneri and S. thunbergii. The complete S. vachellianum cpDNA was 124,582 bp in length and consisted of a pair of inverted repeats (IRs) of 5435 bp, a large single copy (LSC) region of 73,721 bp and a small single copy (SSC) region of 39,991 bp. Totally 160 genes were predicted, including 132 protein-coding genes, four ribosomal RNA genes and 24 tRNA genes, and the coding sequences contributed 77.48% of the whole genome. In addition, 25 SSR loci and 28 highly variable regions were identified from the S. vachellianum cpDNA, which might be used as candidates for developing DNA barcode markers of Sargassum species. The phylogenetic tree based on datasets of all the plastid-encoded proteins demonstrated that species of S. subgenus Bactrophycus were firstly combined and then clustered with S. vachellianum, which belongs to S. subgen. Sargassum. The results indicate that the chloroplast genomes are good resources for developing new DNA markers for taxonomy, and also as tools for evolutionary research of closely related species in future studies.

The mitochondrial genome of Sargassum patens was completely sequenced. This mitogenome is a circular molecule of 34,844 bp in length and had an overall GC content of 36.20%. The mitogenome contains 37 protein-coding, three rRNA, 25 tRNA genes and two conserved open reading frames (ORFs). The Maximum-likelihood (ML) tree showed that S. patens has a closer relationship with S. aquifolium.

The complete S. siliquastrum mitogenome length was 34,765 bp. The mitogenome contains 67 genes, including 37 protein-coding, three rRNA, 25 tRNA genes, and two conserved open reading frames (ORFs). The overall GC content of the genome is 36.59%. The complete mitogenome sequence provided herein would help understand Sargassum evolution.

We describe the complete mitochondrial genome sequence of Sargassum fusiforme. This mitogenome is a circular molecule of 34,695 bp in length and had an overall GC content of 37.54%%. Gene annotation showed that 35 protein-coding genes, 2 open reading frames, 25 transfer RNA genes, and 3 ribosomal RNA genes. The phylogenetic tree based on Bayesian shows that S. fusiforme belongs to genus Sargassum, support current taxonomic systems.

Canopy-forming macroalgae are the main component in some of the most diverse and productive coastal habitats around the world. However, canopy-forming macroalgae are very sensitive to anthropogenic disturbances. In coastal urban areas, intertidal organisms are exposed to the interactive effect of several anthropogenic disturbances that can modify the community’s structure and diversity. Along the North-East Atlantic shores, many studies explored the effect of anthropogenic disturbances on canopy-forming macroalgae, but mainly focused on kelps and fucoids. However, along the intertidal rocky shores of the Atlantic coast of the Iberian Peninsula, the most abundant and frequent canopy-forming macroalgae belong to the family Sargassaceae. To explore the effect of urbanization on these intertidal canopy-forming species the diversity and assemblage structure of canopy species were compared between four urban and four non-urban shores in the north of Portugal. Intertidal canopy assemblages on urban shores were dominated by the non-indigenous Sargassum muticum that was the only canopy-forming species on three of the four studied urban shores. Canopy assemblages on all non-urban shores were more diverse. Moreover, stands of canopy-forming species on urban shores were always monospecific, while at non-urban shores multi-specific stands were common. Therefore, results suggest that urbanization reduces canopy´s biodiversity.

Abstract Four previously undescribed antioxidative O -heterocyclic analogues, characterized as 3″-isopropyl-3c-{3b-[(2-oxo-3,4-dihydro-2 H -chromen-3-yl) methyl] butyl}-2″-butenyl-3′-hydroxy-2′-(2′b-methoxy-2′-oxoethyl)-3′, 4′-dihydro-2 H -pyran-4′-carboxylate (1), 2c-methylbutyl-6-[6c-(benzoyloxy)propyl]-6-methyl-tetrahydro-2 H -pyran-2-carboxylate (2), 6-{6b-[3′-(5′a-methyl propyl)-3′, 4′-dihydro-2 H -pyran-6′-yl] ethyl}-tetrahydro-2 H -pyran-2-one (3) and 7-(7c-methylpentyl)-hexahydro-2 H -chromen-2-one (4) were isolated from the ethylacetate:methanol fraction of the brown seaweed Sargassum wightii. Nuclear magnetic resonance and mass spectroscopic experiments unambiguously attributed their structural identities. Antihypertensive activities of the studied compounds were determined in terms of their angiotensin converting enzyme (ACE) inhibitory potential. The 2 H -pyranylcarboxylate derivative (1) displayed comparable activity (IC 50 0.08 mg/mL) with standard antihypertensive agent captopril (IC 50 0.07 mg/mL). The O -heterocyclic derivatives bearing 2 H -pyran-4′-carboxylate (1) and 2 H -pyran-2-carboxylate (2) frameworks showed significantly greater (p < 0.05) 1, 1-diphenyl-2-picryl-hydrazil radical quenching potential {IC 50 (1) 0.34 and IC 50 (2) 0.45 mg/mL} compared to the standard antioxidant α-tocopherol (IC 50 0.63 mg/mL). Structure-activity relationship analyses demonstrated that the electronic and lipophilic descriptors might significantly contribute towards the target bioactivities of 2 H -pyranylcarboxylates (1 and 2). Molecular docking simulations were carried out for ACE inhibition, and the binding energy obtained for the compounds (~7.04–8.48 kcal/mol) demonstrated their potential enzyme-ligand interactions. The potential of hitherto undescribed O -heterocyclic derivatives as natural antioxidant and antihypertensive functional food supplements and their utilization as therapeutic leads in the antihypertensive management were described in the present study. Graphical abstract Unlabelled Image Highlights • Four new O -heterocyclic analogues were isolated from seaweed Sargassum wightii. • 2 H -pyranylcarboxylates (1 – 2) display greater antioxidant activities than reference. • 2 H -pyran-4′-carboxylate (1) displayed an IC 50 of 0.08 mg/mL against ACE in vitro. • Electronic and lipophilic structural descriptors contributed towards bioactivities. • Molecular docking simulation showed ACE-ligand interactions in hypertension model. [ABSTRACT FROM AUTHOR]

Sargassum in the Caribbean region has affected the livelihood of several coastal communities due to the influx of large quantities of the seaweed in recent times. This article seeks to explore how waste Sargassum natans can be utilized to produce sodium alginate. The novelty in this research lies in the optimization process, whereby multistage extraction and precipitation were investigated over commonly used single stage processing, in an effort to maximize both yield and purity. The results showed that a maximum yield of 19% was observed after 1 stage, while the purity was 74% after 4 stages. In addition, optimization of the multistage precipitation process using the Global Optimization Toolbox in MATLAB R2017b provided a novel model which indicated that a compromise between the maximum purity and yield can be obtained at 3 stages; 71–74% and 12–16% respectively. Furthermore, characterization was done using FTIR and NMR, with results comparable to a commercial sodium alginate brand, giving absorption bands at 1610 cm −1 and 1395 cm -1 and an M/G ratio of 0.51 respectively. [ABSTRACT FROM AUTHOR]

Many brown macroalgal species are difficult to identify because of limited morphological differentiation and/ or high levels of plasticity. Molecular methods for distinguishing species coupled with morphological examination have been useful in clarifying species status in many groups. Cystophora is a species-rich, morphologically complex brown algal genus that has been carefully monographed, and it is ideal for testing the utility of molecular markers for genetic species delimitation. We evaluated the utility of the cytochrome oxidase subunit 1 (COI) DNA-barcode marker, alone and in combination with nuclear-encoded internal transcribed spacer (ITS) rDNA, in delimiting species. We also used several methods to delimit putative genetic species. Our results showed that for consistent species delimitation and species delimitation that approximates morphological species, both markers in combination are necessary. Most species in the genus are morphologically recognizable and genetically distinct but neither COI nor combined COI-ITS data separate Cystophora congesta from Cystophora retroflexa or Cystophora distenta from Cystophora scalaris. We showed that morphological characters used to separate these two species pairs are highly variable among samples, with many intermediates. Thus, we concluded that these are not independent species and synonymize these species. Our data showed that this genus, while widespread, mostly conforms to a morphospecies concept. [ABSTRACT FROM AUTHOR]

The combined effects of photosynthetically active radiation (PAR) and temperature on the photosynthesis of a temperate Japanese brown alga, Sargassum patens (Fucales), were determined by field and laboratory measurements. Underwater measurements of the natural population of this alga in Kagoshima, Japan, revealed that the effective quantum yield (ΦPSII) declined with increasing incident PAR, with minimum ΦPSII occurring during noon to early afternoon. ΦPSII recovered in the evening, indicating dynamic photoinhibition. In laboratory experiments, ΦPSII was also negatively correlated with PAR, which decreased after 12 h of continuous exposure to 200 (low) and 1000 (high) μmol photons m−2 s−1 at 8, 20, and 28 °C. Maximum quantum yield (Fv/Fm) at 8 °C with low PAR failed to recover after 12 h of dark acclimation, suggesting the influence of low temperature in chronic photoinhibition. Photosynthesis-irradiance (P-E) curves likewise revealed lower net photosynthetic rates and photoinhibition at 8 °C. Gross photosynthesis and dark respiration experiments determined over a range of temperatures (8-40 °C) revealed that the maximum gross photosynthetic rate (GPmax) occurred at 26.9 °C. Fv/Fm after 72 h of temperature exposures was stable at 8-32 °C; but it was deactivated at 36 and 40 °C. This species is well-adapted to the current range of temperature in the temperate region of Japan (7-28 °C). However, the combined effects of low temperature and PAR may influence algal photosynthetic efficiency and so may be limiting at the marginal region of northern distribution of this temperate species. [ABSTRACT FROM AUTHOR]

Abstract: Disturbances to ecosystems are often considered in terms of their potential to disrupt the feedbacks maintaining a particular ecosystem regime. The likelihood of doing so, however, will be dependent on the nature of the regime and its resilience to disturbance. Within coral reef ecosystems, shifts from coral‐ to macroalgal dominance are becoming increasingly common and, once established, are difficult to reverse. Most studies to date have focused on the biological removal of macroalgae by herbivores, however, none have considered the resilience of macroalgal beds to physical removal by storms. We simulated the physical removal of macroalgal biomass from Sargassum beds on an inshore coral reef on Australia's Great Barrier Reef, and monitored recovery for 11 months. Trimming Sargassum biomass but leaving the holdfast intact had no detectable effect on the density, height or biomass of Sargassum compared to adjacent intact, or control, areas after 5 months. In areas where holdfasts were also removed, Sargassum biomass recovered to 50% of control biomass after 11 months. Given the importance of holdfasts to the resilience of Sargassum beds, we also investigated the ability of herbivores to remove and/or damage holdfasts. Exposing pieces of dead coral with attached Sargassum holdfasts to local herbivore assemblages resulted in a 70% decline in the number of holdfasts over 4 months compared to those protected from herbivores. Synthesis. Beds of Sargassum are extremely resilient to the physical removal of algal biomass, and as such, storms alone are unlikely to lead to permanent reductions in Sargassum abundance. Persistent reductions in the abundance of macroalgae on degraded coral reefs will not only require the physical or biological removal of algal biomass, but critically, sufficient densities of herbivores capable of removing holdfasts. [ABSTRACT FROM AUTHOR]

The presence ofd-aspartate (d-Asp), a biologically rare amino acid, was evaluated in 38 species of marine macroalgae (seaweeds). Despite the ubiquitous presence of freel-Asp, freed-Asp was detected in only 5 species belonging to the Sargassaceae family of class Phaeophyceae (brown algae) but not in any species of the phyla Chlorophyta (green algae) and Rhodophyta (red algae). All other members of Phaeophyceae, including 3 species classified into the sectionTeretiaof Sargassaceae did not containd-Asp. These results indicate that the presence of freed-Asp in marine macroalgae is restricted only to the Sargassaceae family, excluding the species in the sectionTeretia. Presence of d-Aspartate in macroalgae is restricted to the Sargassaceae family exceptTeretiasection [ABSTRACT FROM PUBLISHER]

Skin aging is a major aesthetic concern for people, and it is produced mainly by reactive oxygen species (ROS) and proteases such as elastase, that degrade elastin. The use of natural molecules is becoming more and more common. Sargassum horridum is a brown seaweed with the potential to prevent skin aging and be a source of bioactive to develop green cosmetics. The objective of this research was to evaluate the radical scavenging activity by the 2,2-diphenyl-1-picryl-hydracyl inhibition (DPPH) and anti-elastase activity of extracts of S. horridum , as well as to describe their early phenolics and saponins profiling by dereplication. Phenolic compounds were extracted by conventional (CONV-SH) and ultrasound-assisted methods (UAE-SH), while saponins were obtained by conventional maceration and semi-purification with n -butanol (F-BuOH). Total phenolic content and phlorotannin content were quantified by the Folin Ciocalteu method. Antioxidant and anti-elastase activity were determined in three extracts by in vitro evaluation. CONV-SH was used to dereplicate phenolic compounds by HPLC-MS, while F-BuOH was used to dereplicate saponins by HPLC. The main results showed that the conventional method of extraction increases the yield of total phenolic, and phlorotannin contents. Antioxidant activity observed in three extracts was between 15 and 45 % of DPPH inhibition, and anti-elastase activity was between 15 and 30 % of inhibition. Diosgenin, a steroidal saponin, and four phenolic compounds belonging to flavonols, tyrosol, and hydroxycinnamic acid classes were identified and reported for the first time in S. horridum. These metabolites are related to anti-aging properties. The present study is the first to evaluate the potential green cosmetic applications of S. horridum from Baja California Sur. This research revealed that S. horridum is an important marine resource in Baja California Sur, Mexico, that can be used as a raw material of metabolites with antiaging properties, because it may prevent the loss of skin elasticity and photo-aging caused by ROS. • Sargassum horridum extracts have anti-aging properties for green cosmetics development. • Bioactive ingredients from S. horridum have antioxidant and anti-elastase activities. • Diosgenin is an important saponin precursor first discovered in S. horridum. • The phenolic compounds of S. horridum are linked to their anti-aging properties. [ABSTRACT FROM AUTHOR]

The mitochondrial genome of Sargassum yezoense (Yamada) Yoshida & T. Konno from Uljin, Korea was completely sequenced. This mitochondrial genome has 34,787 bp in length and consists of 65 genes including 37 protein-coding, three rRNA, and 25 tRNA genes. The overall GC content of the genome is 36.5%.