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Chemical cues from sessile hosts can attract mobile and associated organisms and they are also impotant to maintain associations and overall biodiversity, but the identity and molecular structures of these chemicals have been little explored in the marine environment. Secondary metabolites are recognized as possible chemical mediators in the association between species of Laurencia and Aplysia, but the identity of the compounds has not been established. Here, for the first time, we experimentally verify that the sesquiterpene (+)-elatol, a compound produced by the red seaweed Laurencia dendroidea, is a chemical cue attracting the associated sea hare Aplysia brasiliana. In addition to revealing the nature of the chemical mediation between these two species, we provide evidence of a chemical cue that allows young individuals of A. brasiliana to live in association with L. dendroidea. This study highlights the importance of chemical cues in Laurencia-Aplysia association. [ABSTRACT FROM AUTHOR]

As marine tropical ecosystems deteriorate and lose biodiversity, their communities are shifting to being dominated by a few species, altering ecosystem's functioning and services. Macroalgae are becoming dominant on coral reefs, and are frequently observed outcompeting corals. Turf algal assemblages are the base of energy flow in these systems and one of the most abundant types of macroalgae on coral reefs, but little is known about their biology and diversity. Through molecular and morphological analyses, we identified the turf-forming species Laurencia cervicornis, and by studying seasonal recruitment and the impact of herbivorous fishes on its abundance, we describe its survival strategy. The molecular analyses used a total of 45 rbcL gene sequences including eight current genera within the Laurencia complex and two new sequences of L. cervicornis and strongly support the new combination of Palisada cervicornis comb. nov. In addition, a detailed morphological characterization including the description of reproductive structures is provided. Palisada cervicornis was seen recruiting in all seasons but was typically in low abundance. Specimens grown on tiles in fish exclosure cages were devoured in less than 4 h when offered to fishes. Even though many species of the Laurencia complex have chemicals that deter herbivory, species within the genus Palisada lack feeding deterrents and thus are highly palatable. We suggest that P. cervicornis is a palatable species that seems to survive in the community by obtaining a size-refuge from herbivory within turf communities. [ABSTRACT FROM AUTHOR]

Six new compounds, omaezol, intricatriol, hachijojimallenes A and B, debromoaplysinal, and 11,12-dihydro-3-hydroxyretinol have been isolated from four collections of Laurencia sp. These structures were determined by MS and NMR analyses. Their antifouling activities were evaluated together with eight previously known compounds isolated from the same samples. In particular, omaezol and hachijojimallene A showed potent activities (EC50 = 0.15–0.23 µg/mL) against larvae of the barnacle Amphibalanus amphitrite. [ABSTRACT FROM AUTHOR]

Previous publications list ten species in the Laurencia complex from South Africa with all ascribed to the genus Laurencia sensu stricto. However, the diversity of the complex in South Africa has not yet been re-assessed following the numerous recent taxonomic changes. This study investigated the phylogenetic relationships and taxonomy of this group in South Africa using recent collections. Methods included molecular phylogenetic analyses of plastid rbcL gene sequences (a total of 146; including eleven outgroup taxa) using Maximum Likelihood and Bayesian Inference, and the examination of morphological and anatomical characters, including the number of corps en cerise when present. The seven genera of the Laurencia complex formed monophyletic clades with high posterior probabilities. Seventeen morphotypes were identified: 14 in the genus Laurencia sensu stricto, among which eight corresponded to Laurencia species currently recognized from South Africa and one each to species of Palisada, Chondrophycus, and Laurenciella. The six remaining morphotypes in Laurencia sensu stricto did not match any descriptions and are described here as five new species: Laurencia alfredensis sp. nov., Laurencia dichotoma sp. nov., Laurencia digitata sp. nov., Laurencia multiclavata sp. nov. and Laurencia sodwaniensis sp. nov. and a new variety: Laurencia pumila var. dehoopiensis var. nov . Laurencia stegengae nom. nov. is established to replace Laurencia peninsularis Stegenga, Bolton and Anderson nom. illeg. The diversity is likely greater, with six additional unidentified specimens found in this molecular investigation. These findings place South Africa alongside Australia in having one of the most diverse floras of this group in the world. [ABSTRACT FROM AUTHOR]

The first total synthesis of similisines A and B, a pair of unprecedented polybrominated spiro-trisindole enantiomers isolated from Laurencia similis , and their all stereoisomers had been accomplished in 6 steps from the known 5,6-dibromoindole. The described synthesis avoided any protecting-group manipulations, and the key all-carbon spirocenters were constructed via an intramolecular Friedel-Crafts cyclization. In addition, the rotamers of similisines and cytotoxic and NO production inhibitory activities of synthetic compounds were also discussed. [ABSTRACT FROM AUTHOR]

The marine red algae of the genus Laurencia have been widely studied for their structurally diverse and biologically active secondary metabolites. We report here the natural product investigation of the organic extract of a newly identified South African endemic species, Laurencia alfredensis. A sequence of column chromatography, preparative TLC and normal phase HPLC resulted in the isolation of eleven compounds comprising three labdane-type diterpenes (1-3), four polyether triterpenes (4-7), three cholestane-type ecdysteroids (8-10) and a glycolipid (11). Compounds 1-3, 5-8 and 10 have not previously been reported, while compound 9 is reported here for the first time from a natural source and the known compound 11 isolated for the first time from the genus Laurencia. The structural elucidation and the relative configuration assignments of the compounds were accomplished by extensive use of 1D- and 2D-NMR, HR-ESI-MS, UV and IR spectroscopic techniques, while the absolute configuration of compound 1 was determined by single-crystal X-ray diffraction analysis. All compounds were evaluated against the MDA-MB-231 breast and HeLa cervical cancer cell lines. Compound 2 exhibited low micromolar antiproliferative activity (IC50 = 9.3 μM) against the triple negative breast carcinoma and compound 7 was similarly active (IC50 = 8.8 μM) against the cervical cancer cell line. [ABSTRACT FROM AUTHOR]

SUMMARY Laurencia majuscula has recently been determined to be conspecific with Laurencia dendroidea. To determine the correct taxonomic placement of its only non-typical variety, L. majuscula var. elegans, mitochondrial COI-5P and chloroplast rbcL gene sequences were analyzed and its phylogenetic position was inferred. Laurencia majuscula var. elegans consistently formed a well-supported clade distinctly separate from the L. dendroidea clade. Molecular analyses revealed that L. majuscula var. elegans generally shows two distinct forms; a long-branched form, and a compact form. Often the compact form has been identified as a different species based on morphology alone. Included in these analyses were topotype sequences of two species with which L. majuscula var. elegans is most often misidentified; Laurencia nidifica and Laurencia mcdermidiae. Laurencia nidifica formed a well-supported clade separate from L. majuscula var. elegans. Laurencia mcdermidiae, however, formed a well-defined clade sister to the L. majuscula var. elegans clade. Morphological comparisons were also made. It is concluded that L. majuscula var. elegans is morphologically distinct from L. dendroidea, L. nidifica, and L. mcdermidiae. It is proposed that L. majuscula var. elegans be reinstated to species level as L. elegans. [ABSTRACT FROM AUTHOR]

Recently, the phenomenon of enantiodivergence was uncovered as a new phenomenon in the biosynthesis of natural products. In nature, chiral natural products are usually produced in optically active form, but both enantiomers sometimes arise in different genera and/or species or in a single species. Here we show through enantioselective total synthesis that the natural product isodehydrothyrsiferol shows partial enantiodivergency in that six of the nine or ten asymmetric centers are enantiomeric to those of other members of the marine squalene-derived triterpenoid thyrsiferol family. In addition, isodehydrothyrsiferol and dehydrothyrsiferol, which show partial enantiodivergency, were isolated from the same producer, the red alga Laurencia viridis. These results demonstrate that partial enantiodivergence can develop even between natural products originating from a single species. [ABSTRACT FROM AUTHOR]

An ethyl acetate (EtOAc) extract of Laurencia nidifica was found to have toxic effect against brine shrimp larvae (Artemia salina). Bioassay-guided fractionation of the EtOAc extract resulted in the isolation of four known halogenated sesquiterpenes, laurinterol (1), isolaurinterol (2), aplysin (3), and α-bromocuparene (4). Their structures were established on the basis of spectral analysis and comparison with literature data. Among isolated compounds, only laurinterol showed strong toxicity against A. salina. Further experiments revealed that laurinterol also exhibited repellent activity against the maize weevil Sitophilus zeamais, insecticidal activity against the termite Reticulitermes speratus, and acetylcholinesterase (AChE) inhibitory effect. This is the first report of insecticidal and repellent activities of laurinterol. [ABSTRACT FROM AUTHOR]

Currently, sustainability is one of the most critical issues confronting society today. The growing of macroalgae in ocean farms appears more sustainable than agriculture on land due to it does not require any fresh water, chemical fertiliser, or soil. Macroalgae have been shown to be a sustainable marine source of amino acids, novel bioactive phenolic and aroma compounds that can be exploitation in food, cosmetic, nutraceuticals, pharmacological applications. Despite starting the huge cultivation of macroalgae in world, bioactive compounds in the edible macroalgae have not been well characterized. Ultrasound assisted extraction (UAE) and conventional extraction (CE) techniques were compared and red macroalgae, L. papillosa extracts were characterized. The highest amount of amino acid was glutamic acid (GLU) and composed of 35% was essential amino acids. UAE at 10% amplitude for 15 min showed significantly highest (p < 0.05) phenolic (212.03±3.03 mg gallic acid equivalent/100 g) as well as antioxidant activity determined by DPPH (105.69±3.02 µmol Trolox/100 g), ABTS (238.69±2.23 µmol Trolox/100 g) radical assay and FRAP value (72.47±3.13 µmol Trolox/100 g) when in comparison with CE. Furthermore, bioactive compounds in extracts were indicated as phlorotannins, flavonoids, phenolic acids and other polyphenols using liquid chromatography coupled to diode array detection and electrospray ionisation tandem mass spectrometry (LC-DAD-ESI-MS/MS). This result confirmed higher antioxidant capacity detected with the UAE. A total of 46 volatile organic compounds were identified and quantified by GC-FID/MS with HS-SPME system. This study emerges as first report to novel extraction method used and deeply characterization of L papillosa. The results seem that significant potential application in the functional food, active packaging and nutraceuticals industry., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

A new irieane-type diterpene, 12-hydroxypinnaterpene C (1), and 21 known compounds, angasiol acetate (2), angasiol (3), 11-deacetylpinnaterpene C (4), palisadin A (5), 12-acetoxypalisadin B (6), 12-hydroxypalisadin B (7), aplysistatin (8), luzodiol (9), 5-acetoxy-2-bromo-3-chloro-chamigra-7(14),9-dien-8-one (10), neoirietriol (11), neoirietetraol (12), (3Z)-laurenyne (13), cupalaurenol (14), cupalaurenol acetate (15), (3Z)-venustinene (16), 10-hydroxykahukuene B (17), aplysiol B (18), (3Z)-13-epipinnatifidenyne (19), 3Z,6R,7R,12S,13S-obtusenyne (20), (3Z,9Z)-7-chloro-6-hydroxy-12-oxo-pentadeca-3,9-dien-1-yne (21), and cholest-7-en-3,5,7-triol (22) were isolated from the digestive diverticula of Aplysia argus from the Ikei Island in Okinawa, Japan. The structures of these compounds were determined using spectroscopic methods such as NMR and HR-ESI-MS. These compounds were tested for their antibacterial activity against the phytopathogen Ralstonia solanacearum. Compounds 11 and 21 exhibited antibacterial activity at 30 μg/disc. In this study, we also discuss the types of red algae that A. argus feeds on in the shallow waters of Okinawa Prefecture., (© 2023 Wiley-VHCA AG, Zurich, Switzerland.)

Neorogioltriol is a tricyclic brominated diterpenoid isolated from the organic extract of the red algae Laurencia glandulifera. In the present study, the anti-inflammatory effects of neorogioltriol were evaluated both in vivo using carrageenan-induced paw edema and in vitro on lipopolysaccharide (LPS)-treated Raw264.7 macrophages. The in vivo study demonstrated that the administration of 1 mg/kg of neorogioltriol resulted in the significant reduction of carregeenan-induced rat edema. In vitro, our results show that neorogioltriol treatment decreased the luciferase activity in LPS-stimulated Raw264.7 cells, stably transfected with the NF-κB-dependent luciferase reporter. This effect on NF-κB activation is not mediated through MAPK pathways. The inhibition of NF-κB activity correlates with decreased levels of LPS-induced tumor necrosis factor-alpha (TNFα) present in neorogioltriol treated supernatant cell culture. Further analyses indicated that this product also significantly inhibited the release of nitric oxide and the expression of cyclooxygenase-2 (COX-2) in LPS-stimulated Raw264.7 cells. These latter effects could only be observed for neorogioltriol concentrations below 62.5 µM. To our knowledge, this is the first report describing a molecule derived from Laurencia glandulifera with anti-inflammatory activity both in vivo and in vitro. The effect demonstrated in vitro may be explained by the inhibition of the LPS-induced NF-κB activation and TNFα production. NO release and COX-2 expression may reinforce this effect.

Abstract: Since the conception of the genus Laurencia by Lamouroux in 1813, several red macroalgal species have been included in it. In recent decades, the development of modern molecular tools has resulted in multiple taxonomic modifications, and presently, eight related genera are recognized in the so-called Laurencia complex. In the Macaronesian Region (Central East Atlantic Ocean), species from the Laurencia complex are keystone elements of the benthic communities, especially in the intertidal zone. In this review, we consolidate the existing knowledge about the Laurencia complex within the Macaronesian archipelagos and nearby areas. Morphological descriptions and phylogeographic remarks of the 16 currently accepted species—whose records were molecular or morphologically confirmed—are included together with an identification key for the Macaronesian Region. The phylogeographic data allowed us to re-visit the role of the Macaronesian archipelagos as a bridge area for the marine flora of the Mediterranean and Caribbean Seas (remnants of the former Thetyan Sea) or contemplate their marine flora as the result of successive processes of recolonization after the Quaternary glaciations from those donor areas. Finally, some comments about the frontiers of the research in the Laurencia complex in the Macaronesian Region and nearby coastal areas are included.

The molecular systematics of Laurencia, Osmundea and Palisada (Rhodomelaceae, Ceramiales) species from the Canary Islands has been determined by analysis sequences of the ribulose,1-5, bisphosphate carboxylase (RUBISCO) spacer from the plastid genome and the internal transcribed spacers (ITS1 and ITS2) and the rDNA 5.8S coding region from the nuclear genome. Comparison of sequence data showed an identity of 72-83 % between the species. Three taxonomic group were identified that correspond to established phylogenetic taxons. Phylogenetic trees using both parsimony and maximum-likelihood methods were derived from the sequence data; the trees indicate that O. pinnatifida appears to be the most distantly related species from the Laurencia and Palisada species. The exact phylogenetic position of Laurencia sp. A (“amarilla”) need additional studies.

The red seaweed Laurencia dendroidea belongs to the Rhodophyta, a phylum of eukaryotic algae that is widely distributed across the oceans and that constitute an important source of bioactive specialized metabolites. Laurencia species have been studied since 1950 and were found to contain a plethora of specialized metabolites, mainly halogenated sesquiterpenes, diterpenes and triterpenes that possess a broad spectrum of pharmacological and ecological activities. The first committed step in the biosynthesis of triterpenes is the cyclization of 2,3-oxidosqualene, an enzymatic reaction carried out by oxidosqualene cyclases (OSCs), giving rise to a broad range of different compounds, such as the sterol precursors cycloartenol and lanosterol, or triterpene precursors such as cucurbitadienol and β-amyrin. Here, we cloned and characterized the first OSC from a red seaweed. The OSC gene was identified through mining of a L. dendroidea transcriptome dataset and subsequently cloned and heterologously expressed in yeast for functional characterization, which indicated that the corresponding enzyme cyclizes 2,3-oxidosqualene to the sterol precursor cycloartenol. Accordingly, the gene was named L. dendroidea cycloartenol synthase (LdCAS). A phylogenetic analysis using OSCs genes from plants, fungi and algae revealed that LdCAS grouped together with OSCs from other red algae, suggesting that cycloartenol could be the common product of the OSC in red seaweeds. Furthermore, profiling of L. dendroidea revealed cholesterol as the major sterol accumulating in this species, implicating red seaweeds contain a ‘hybrid’ sterol synthesis pathway in which the phytosterol precursor cycloartenol is converted into the major animal sterol cholesterol. [ABSTRACT FROM AUTHOR]

The first asymmetric total synthesis and subsequent structure revision of (-)-bisezakyne A, a Laurencia C15 acetogenin from Alpysia oculifera, has been accomplished. Our substrate-controlled synthesis of this oxolane natural product features a highly stereoselective "protecting-group-dependent" intramolecular amide enolate alkylation strategy for the synthesis of the key 9,10-trans-9,12-cis-10-hydroxytetrahydrofuran intermediate through "nonchelate" control. In addition, our synthesis determined the absolute configuration of the halogenated marine natural product. [ABSTRACT FROM AUTHOR]

Four new minor brominated indole related alkaloids (one indoles, 1 , one 1,3-dihydro-indole-2-one, 2 , one carbazole, 3 , and one 2-carbonylamino-benzoate, 4 ) were isolated and identified from Laurencia similis by extensive chromatographic and spectrometric methods. Among them, 1 and 2 were the first example of naturally occurring indole with 3-benzyl group and 1,3-dihydro-indole-2-one with 2-isopropylidene group, respectively, whereas 3 and 4 were the first carbazole alkaloids and 2-carbonylamino-benzoate, respectively, isolated from the genus Laurencia. Moreover, 1 showed the most potent antibacterial activity against seven bacterial strains with MIC values ranging from 2 to 8 μg/mL. [ABSTRACT FROM AUTHOR]

Response surface methodology was used to investigate the effect of ultrasound-assisted extraction conditions including solvent:seaweed ratio (10:1–30:1), extraction temperature (30–50°C), and extraction time (30–60 min) on the total phenolic compounds and antioxidant activity of red seaweed (Laurencia obtuse) extracts. The optimum extraction parameters for maximum phenolic content were as follows: solvent:seaweed ratio, 30:1; extraction temperature, 50°C; and extraction time, 42.8 min. The experiment results showed that the solvent:seaweed ratio was the most significant parameter for the extraction. The optimum extraction conditions for maximum antioxidant activity were as follows: solvent:seaweed ratio, 24.3:1; extraction temperature, 45.3°C; and extraction time, 58 min. Under the above-mentioned conditions, the experimental total phenolic content and antioxidant activity value were 26.23 ± 0.75 mg GAE/g seaweed and 120.89 ± 0.81 TEAC, respectively, of seaweed tested, which are well compatible with the predicted contents. [ABSTRACT FROM AUTHOR]

Background: Red algae of the genus Laurencia J. V. Lamouroux are a rich source of secondary metabolites with important pharmacological activities such as anti-tumoral, anti-inflammatory, anti-fungal, anti-viral, anti-leishmanial, anti-helminthic, anti-malarial, anti-trypanosomal, anti-microbial as well as anti-bacterial against Mycobacterium tuberculosis. Objective: In the present study, we evaluated the inhibition of nitric oxide (NO) and tumor necrosis factor-α production and the anti-mycobacterial activity of crude extracts from the red Alga Laurencia dendroidea (from the South-Eastern coast of Brazil). Halogenated sesquiterpenes elatol (1), obtusol (2) and cartilagineol (3), previously isolated from this Alga by our group, were also studied. Materials and Methods: The lipopolysaccharide-activated macrophage cells (RAW 264.7) were used as inflammation model. Cytotoxic effect was determined using a commercial lactate dehydrogenase (LDH) kit and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The growing Mycobacterium inhibition was verified against Mycobacterium bovis Bacillus Calmette–Guérin and M. tuberculosis H37Rv strains. Results: The crude extract from Alga collected at Angra dos Reis, RJ, Brazil, was the most active inhibitor of both mycobacterial growth (half maximal inhibitory concentration [IC50] 8.7 ± 1.4 μg/mL) and NO production by activated macrophages (IC50 5.3 ± 1.3 μg/mL). The assays with isolated compounds revealed the anti-mycobacterial activity of obtusol (2), whereas (-)-elatol (1) inhibited the release of inflammatory mediators, especially NO. To our knowledge, this is the first report describing an anti-mycobacterial effect of L. dendroidea extract and demonstrating the association of this activity with obtusol (2). Conclusion: The described effects of active compounds from L. dendroidea are promising for the control of inflammation in infectious diseases and specifically, against mycobacterial infections associated with exacerbated inflammation. [ABSTRACT FROM AUTHOR]

Variability in the production of secondary metabolites by seaweeds is commonly measured under natural conditions and is usually considered a response to environmental factors. However, it is not well known if levels of secondary metabolites can vary due to internal regulation of physiological processes. We measured the diel levels of elatol - the major defensive compound of Laurencia dendroidea - in correlation with the activity of photosystem II (Φ PSII ) in clones of this seaweed cultivated under constant conditions of temperature, salinity, nutrient availability and irradiance. Our results showed temporal variation in amounts of elatol, which peaked at the beginning of the light and dark periods. The Φ PSII during the light phase, as measured by chlorophyll fluorescence imaging, was higher when the elatol concentration was lower. We conclude that under constant conditions, i.e. without the influence of natural habitat and genetic variability, there is diel variation in elatol production that is inversely correlated with Φ PSII . We suggest that both metabolic activity of secondary metabolite production and photosynthetic activity are under an endogenous control in this red seaweed. We discuss the possible adaptive responses of this phenomenon to environmental pressures. [ABSTRACT FROM AUTHOR]

Chemical investigation of the marine red alga Laurencia pinnata collected from Nanji Island of China resulted in the isolation and identification of three new eudesmane (selinane) sesquiterpenes, 1β-bromoselin-11-en-4α-ol ( 1 ), 1β-bromo-4α,5α-epoxyselinane ( 2 ), and 1β-bromoselin-3,11-diene ( 3 ), and one new 6,8-cycloeudesmane sesquiterpene, 1β-bromo-6,8-cycloselin-4(15)-ene ( 4 ), together with one known eudesmane sesquiterpene, 1β-bromoselin-4(15),11-diene ( 5 ), two known chamigrane sesquiterpenes, 2,10-dibromo-3-chlorochamigr-7-ene ( 6 ) and 2,10-dibromo-3-chlorochamigr-7-en-9-ol ( 7 ), one kahukuane diterpene, kahukuene B ( 8 ), and one parguerane diterpene, 15-bromoparguer-9(11)-en-16-ol ( 9 ). These halogenated isolates were found in L . pinnata for the first time, and they support the taxonomic position of this species under the genus Laurencia . Eudesmane derivatives ( 1 – 5 ) are predominant and rarely reported from this genus, and they may be taken as chemotaxonomic markers for L. pinnata in the future. [ABSTRACT FROM AUTHOR]

A new Bis-sesquiterpene, Nanji A ( 1 ), has been isolated together with 7 known compounds, debromolaurinterol ( 2 ), laurinterol ( 3 ), laurinterol acetate ( 4 ), isolaurinterol ( 5 ), 3α-hydroperoxy-3-epiaplysin ( 6 ), 3β-hydroperoxyaplysin ( 7) , Laurokomurenene A ( 8 ), from the Nanji red alga Laurencia okamurai . The structure of 1 was elucidated on the basis of extensive spectroscopic analysis of its EIMS, 1D and 2D NMR data. Furthermore, the chemotaxonomic significance of these compounds was also summarized. [ABSTRACT FROM AUTHOR]

Red algae of Laurencia continue to provide wide structural diversity and complexity of halogenated C15 acetogenin medium-ring ethers. Here, we described the isolation of three new C15 acetogenins (3–5), and one truncated derivative (6) from Laurencia viridis collected on the Canary Islands. These compounds are interesting variations on the pinnatifidenyne structure that included the first examples of ethynyl oxirane derivatives (3–4). The structures were elucidated by extensive study of NMR (Nuclear Magnetic Resonance) data, J-based configuration analysis and DFT (Density Functional Theory) calculations. Their antiproliferative activity against six human solid tumor cell lines was evaluated.

Background: Biosynthesized nanoparticles are gaining popularity due to their distinctive biological applications as well as bioactive secondary metabolites from natural products that contribute in green synthesis., Methodology: This study reports a facile, ecofriendly, reliable, and cost-effective synthesis of silver nanoparticles (AgNPs), copper oxide nanoparticles (CuONPs), and polymeric PVP-silver-copper oxide nanocomposite using ethanol extract of seaweed Laurencia dendroidea and were evaluated for antiprotozoal, anticancer and photocatalytic potential. The nanostructures of the AgNPs, CuONPs, and polymeric PVP-Ag-CuO nanocomposite were confirmed by different spectroscopic and microscopic procedures., Results: The UV-vis spectrum displayed distinct absorption peaks at 440, 350, and 470 nm for AgNPs, CuONPs, and polymeric Ag-CuO nanocomposite, respectively. The average particles size of the formed AgNPs, CuONPs, and Ag-CuO nanocomposite was 25, 28, and 30 nm, respectively with zeta potential values -31.7 ± 0.6 mV, -17.6 ± 4.2 mV, and -22.9 ± 4.45 mV. The microscopic investigation of biosynthesized nanomaterials revealed a spherical morphological shape with average crystallite sizes of 17.56 nm (AgNPs), 18.21 nm (CuONPs), and 25.46 nm (PVP-Ag-CuO nanocomposite). The antiprotozoal potential of green synthesized nanomaterials was examined against Leishmania amazonensis and Trypanosoma cruzi parasites. The polymeric PVP-Ag-CuO nanocomposite exerted the highest antiprotozoal effect with IC 50 values of 17.32 ± 1.5 and 17.48 ± 4.2 µM, in contrast to AgNPs and CuONPs. The anticancer potential of AgNPs, CuONPs, and polymeric PVP-Ag-CuO nanocomposite against HepG2 cancer cell lines revealed that all the nanomaterials were effective and the highest anticancer potential was displayed by PVP-Ag-CuO nanocomposite with IC 50 values 91.34 µg mL -1 at 200 µg mL -1 concentration. Additionally, PVP-Ag-CuO nanocomposite showed strong photocatalytic effect., Conclusion: Overall, this study suggested that the biogenic synthesized nanomaterials AgNPs, CuONPs, and polymeric PVP-Ag-CuO nanocomposite using ethanol extract of seaweed L. dendroidea possesses promising antiprotozoal anticancer and photocatalytic effect and could be further exploited for the development of antiprotozoal and anticancer therapeutics agents., Competing Interests: The authors declare there are no competing interests., (©2023 Amina et al.)

The present study described with different microscopy approaches chloroplasts lobes in Laurencia sensu latu (Rhodophyta) species and found inter-specific differences among them. Chloroplasts were investigated using confocal laser scanning microscopy (LSM), transmission electron microscopy (TEM) and high resolution scanning electron microscopy (HRSEM). Using and TEM and HRSEM images we distinguished chloroplasts with lobes than chloroplasts without lobes in Yuzurua poiteaui var. gemmifera (Harvey) M. J. Wynne and Laurencia dendroidea J. Agardh cortical cells. The LSM images showed chloroplasts lobes (CLs) with different morphologies, varying from thicker and longer undulated projections in Y. poiteaui var. and L. dendroidea to very small and thin tubules as in Laurencia translucida Fujii & Cordeiro-Marino. The diameter and length of CLs from Y. poiteaui var. and L. dendroidea were significantly higher than L. translucida CLs (p < 0.01). Based on LSM observations, we suggest that lobes morphology has a taxonomic validity only to characterize L. translucida species. [ABSTRACT FROM AUTHOR]

Within the Laurencia complex (Rhodophyta, Rhodomelaceae), six genera have been recognized based on both molecular analyses and morphology: Laurencia, Osmundea, Chondrophycus, Palisada, Yuzurua, and Laurenciella. Recently, new material from Australia has been collected and included in the current molecular phylogeny, resulting in a new clade. This study examined the generic delineations using a combination of morphological comparisons and phylogenetic analysis of chloroplast ( rbcL) nucleotide sequence. The molecular phylogeny recovered eight (rather than six) clades; Yuzurua, Laurenciella, Palisada, and Chondrophycus showed as monophyletic clades each with strong support. However, the genera Osmundea and Laurencia were polyphyletic. Consequently, the new genus Coronaphycus is proposed, resulting in the new combination Coronaphycus elatus and a description of the new species C. novus. [ABSTRACT FROM AUTHOR]

The sterol content of Laurencia obtusa var. pyramidata (Hudson) J. V. Bory ex. J. Agardh collected from Igneada, in the western part of the Black Sea coast of Turkey, was analyzed. They were cholest-5-en-3-ol (cholesterol), β-sitosterol, ergosta-5,7,22-trien-3- ol (ergosterol), 24-norcholesta-5,22(E)-dien-3β-ol, cholest-5,22(E)-dien-3β-ol, ergosta- 5,24(28)-dien-3β-ol, 27-norergosta-5,22(E)-dien-3β-ol, ergosta-5, 22(E)-dien-3-ol, 23(S)- methylcholesterol, 23(S)-ethylcholesterol. The latter four were found in Laurencia species for the first time. [ABSTRACT FROM AUTHOR]

Sierra Los Tanques is located in NW Sonora, Mexico, and represents one of the main outcrops of Permo-Triassic granitic rocks reported in the region. U-Pb zircon geochronology conducted in two groups of granitoids from various locations in NW Sonora provide a range of ages between 284 - 221 Ma. Rock types are dominated by granodiorite, followed by quartzmonzodiorites, and monzogranites. There are two main granitic suites-leucocratic and melanocratic granitoids. Field relationships between the two types suggests that the melanocratic granitoids are older as they are clearly intruded by the leucocratic suite. This field evidence is supported, in most cases, by the U-Pb zircon ages obtained in samples of both granitic suites. Most of the zircons from these Permo-Triassic granitoids have high U concentrations (~ 47 - 9508 ppm), suggesting significant Pb loss in their crystal structure. The Permo-Triassic zircons show highly variable Th/U ratios (0.01 - 0.73). These zircons have an igneous origin not only because of their prismatic morphologies, but also due to their oscillatory zoning characteristic of magmatic growth as observed in cathodoluminescence studies. The presence of inherited cores, as shown in cathodoluminescence images, can be associated with the ages of meta-igneous Proterozoic basement present in Sierra Los Tanques (~ 1.7 - 1.6 Ga, ~ 1.4 Ga and ~ 1.1 Ga) that could have been incorporated during magma-genesis in Permo-Triassic time. These granitoids associated with subduction give evidence for the beginning of cordilleran arc magmatism in SW North America (Laurentia) established along the western margin of Pangea immediately following the latest stages of the collision between Laurentia and Gondwana. This Permo-Triassic magmatism is important for understanding the tectonic evolution of NW Mexico. Tentatively, the occurrence of this magmatism is associated with a zone of crustal weakness spatially associated with the Mexican Yavapai basement province in NW Sonora. Understanding this magmatic pulse is also of particular importance as it represents a regional source of detrital Permo-Triassic zircons previously unrecognized for Mesozoic and Cenozoic sedimentary basins in Sonora and southern Arizona. Lastly, this Permo-Triassic subduction-related magmatic pulse present in NW Sonora is part of a larger magmatic arc event along the American Cordillera that extends from western-southwestern United States, passing through northern, central, and southern Mexico and reaching northern South America. [ABSTRACT FROM AUTHOR]