Laurencia Complex Research Articles

CE–MS fingerprinting of Laurencia complex algae (Rhodophyta)

The use of CE-ESI-MS has been considered as a new chemical strategy for the possible discernment of genera and species of the Laurencia complex. After the selection of the CE-MS and the extraction conditions, a total of 28 specimens of the complex, including different species of four genera (Laurencia, Laurenciella, Palisada, and Osmundea) collected from five intertidal locations on the Island of Tenerife (Canary Islands, Spain) were analyzed. CE-MS fingerprints revealed that CE-MS can be used as a useful tool for these studies in order to assess similarities and differences between them and that it constitutes an important starting point for further studies in the field.

Mycosporine-like amino acids (MAAs): qualitative analysis of photoprotective compounds in Laurencia complex seaweed species (Ceramiales, Rhodophyta) from Espírito Santo State, Brazil

Mycosporine-like amino acids (MAAs): qualitative analysis of photoprotective compounds in Laurencia complex seaweed species (Ceramiales, Rhodophyta) from Espírito Santo State, Brazil

Molecular support for the establishment of the new genus Laurenciella within the Laurencia complex (Ceramiales, Rhodophyta)

Abstract Currently, five genera are assigned to red seaweeds of the Laurencia complex worldwide: Chondrophycus, Laurencia s.s., Osmundea, Palisada and Yuzurua. The genera are segregated on the basis of morphological characters, especially the reproductive traits, and molecular sequences of the plastid-encoded gene rbcL. Four of the genera have been resolved as monophyletic, but not Laurencia s.s. In this study based on an rbcL gene phylogeny we show the presence of a sixth lineage within the Laurencia complex, viz., Laurencia marilzae plus two unidentified species of Laurencia from Brazil. The phylogenetic position of this group, combined with the high genetic divergence from Laurencia s.s. (8.2–11%), strongly support the establishment of a sixth genus for the complex, proposed here as Laurenciella gen. nov. This new taxon differs from Laurencia s.s. and from the other genera of the complex by molecular sequence data, but is indistinguishable from Laurencia s.s. by the usual morphological features.

Comparative analysis of the corps en cerise in several species of Laurencia (Ceramiales, Rhodophyta) from the Atlantic Ocean

Different species of Laurencia have proven to be a rich source of natural products yielding interesting bioactive halogenated secondary metabolites, such as terpenoids and acetogenins. It is shown that such compounds are accumulated in the spherical, reniform to claviform refractive inclusions called corps en cerise (CC), which are intensively osmiophilic and located mainly in the cortical cells of the thalli and also in trichoblast cells. Up to now, it was believed that CC were present only in these two kinds of cells. Recently, however, a species of Laurencia, L. marilzae, with CC in all cells of the thallus, i.e., cortical, medullary, including the pericentral and axial cells, as well as in the trichoblasts, was described from the Canary Islands, and subsequently also reported to Brazil and Mexico. Within the Laurencia complex, only Laurencia species produce CC. Since the species of Laurencia are targets of interest for the prospection of bioactive substances due to their potential antibacterial, antifungal, anticholinesterasic, antileishmanial, cytotoxic, and antioxidant activities, the present paper carries out a comparative analysis of the corps en cerise in several species of Laurencia from the Atlantic Ocean to obtain basic information that can support natural product bioprospection projects. Our results show that the number and size of the CC are constant within a species, independent of the geographical distribution, corroborating their use for taxonomical purposes to differentiate groups of species that present a lower number from those that have a higher number. In this regard, there was a tendency for the number of CC to be higher in some species of Laurencia from the Canary Islands. The presence of CC can also be used to distinguish species in which these organelles are present in all cells of the thallus from those in which CC are restricted to the cortical cells. Among the species analyzed, L. viridis displayed the most varied secondary metabolites composition, such as sesquiterpenes, diterpenes, triterpenes, all of which showed potent antiviral, cytotoxic, and antitumoral activities, including protein phosphatase type 2A (PP2A) inhibitory effects.

Chemical structure of the complex pyruvylated and sulfated agaran from the red seaweed Palisada flagellifera (Ceramiales, Rhodophyta)

A homogeneous agaran fraction from Palisada flagellifera ( Laurencia complex, Rhodomelaceae, Ceramiales) was obtained by aqueous room-temperature extraction, followed by ion-exchange chromatography. This galactan presents a highly complex structure with at least 18 different types of derivatives. The A units were found mostly pyruvylated, 2-sulfated (∼34%), and 6-methylated (∼34%), with the latter partially 2- and 2,4-sulfated. Minor amounts of β- d-galactopyranosyl units 2-, 6- and 2,6-sulfated, 6-glycosylated, and non-substituted are also present. The B-units are l-sugars composed predominantly of their cyclized derivatives, 3,6-anhydrogalactose and 3,6-anhydro-2- O-methylgalactose (∼56%). The former are linked to β- d-galactosyl (6-methyl) (6-glycosylated) units, as well as to 4,6- O-(1-carboxyethylidene)-β- d-galactose 2-sulfate in the proportion of 3:1.8, respectively. A significant amount (∼18%) of the α- l-galactopyranosyl units are linked to pyruvylated β- d-galactose 2-sulfate residues. An important part of the B-units (20%) is represented by α- l-galactose 6-sulfate substituted on C-3 by xylosyl, galactosyl and/or 2,3-di- O-methylgalactose units or sulfate groups that preclude their cyclization to 3,6-anhydrogalactosyl derivative. The precursor units are present in relatively low percentages. Kinetic studies suggest that in P. flagellifera agaran the cyclizable units are linked to 6- O-methyl-β- d-galactosyl and/or β- d-galactosyl units (6-glycosylated). The structural complexity of this polysaccharide is increased by the presence of 2- and 3,6-sulfated α- l-galactoses, with the latter additionally 2-O-methylated. Therefore, the major subfraction obtained from the cold extract contains structurally complex sulfated, methylated, and pyruvylated agaran.

Overview of the taxonomy and of the major secondary metabolites and their biological activities related to human health of the Laurencia complex (Ceramiales, Rhodophyta) from Brazil

In Brazil, the Laurencia complex is represented by twenty taxa: Laurencia s.s. with twelve species, Palisada with four species (including Chondrophycus furcatus now that the proposal of its transference to Palisada is in process), and Osmundea and Yuzurua with two species each. The majority of the Brazilian species of the Laurencia complex have been phylogenetically analyzed by 54 rbcL sequences, including five other Rhodomelacean species as outgroups. The analysis showed that the Laurencia complex is monophyletic with high posterior probability value. The complex was separated into five clades, corresponding to the genera: Chondrophycus, Laurencia, Osmundea, Palisada, and Yuzurua. A bibliographical survey of the terpenoids produced by Brazilian species showed that only six species of Laurencia and five of Palisada (including C. furcatcus) have been submitted to chemical analysis with 48 terpenoids (47 sesquiterpenes and one triterpene) isolated. No diterpenes were found. Of the total, 23 sesquiterpenes belong to the bisabolane class and eighteen to the chamigrene type, whose biochemical precursor is bisabolane, two are derived from lauranes and four are triquinols. Despite the considerable number of known terpenes and their ecological and pharmacological importance, few experimental biological studies have been performed. In this review, only bioactivities related to human health were considered.

Search for cytotoxic agents in multiple Laurencia complex seaweed species (Ceramiales, Rhodophyta) harvested from the Atlantic Ocean with emphasis on the Brazilian State of Espírito Santo

The development of new anti-cancer drugs of algal origin represents one of the least explored frontiers in medicinal chemistry. In this regard, the diversity of micro- and macroalgae found in Brazilian coastal waters can be viewed as a largely untapped natural resource. In this report, we describe a comparative study on the cytotoxic properties of extracts obtained from the Laurencia complex: Laurencia aldingensis, L. catarinensis, L. dendroidea, L. intricata, L. translucida, L. sp, and Palisada flagellifera. All of these species were collected in the coastal waters of the State of Espirito Santo, Brazil. Four out of the twelve samples initially investigated were found to show significant levels of toxicity towards a model tumor cell line (human uterine sarcoma, MES-SA). The highest levels of cytotoxicity were typically associated with non-polar (hexane) algal extracts, while the lowest levels of cytotoxicity were found with the corresponding polar (methanol) extracts. In this report, we also describe a biological model currently in development that will not only facilitate the search for new anti-cancer drug candidates of algal origin, but also permit the identification of compounds capable of inducing the destruction of multi-drug resistant tumors with greater efficiency than the pharmaceuticals currently in clinical use.

Tissue culture of three species of Laurencia complex

To establish a micropropagation system of three Laurencia complex species (Laurencia okamurai, Laurencia tristicha, and Chondrophycus undulatus) by tissue culture techniques, we studied the regeneration characteristics and optimal culture conditions of axenic algal fragments cultured on solid medium and in liquid medium. Regeneration structures were observed and counted regularly under a reverse microscope to investigate the regeneration process, polarity and optimal illumination, and temperature and salinity levels. The results show that in most cultures of the three species, we obtained bud regeneration on solidified medium with 0.5% agar and in liquid medium. Rhizoid-like regeneration was filamentous and developed from the lower cut surface of fragments in L. okamurai, but was discoid and developed from the apical back side of bud regeneration in L. tristicha and C. undulatus. Regeneration polarity was localized to the apical part of algal fronds in all three species, and on fragments cut from the basal part of algae buds could develop from both the upper and the lower cut surfaces. Buds could develop from both the medullary and the cortical portions in L. okamurai and C. undulatus, while in L. tristicha, buds only emerged from the cortex. The optimal culture conditions for L. okamurai were 4 500 lx, 20°C and 35 (salinity); for C. undulatus, 4 500 lx, 20°C and 30; and for L. tristicha, 4 500 lx, 25°C and 30.

Phylogenetic analyses of the Laurencia complex (Rhodomelaceae, Ceramiales) support recognition of five genera: Chondrophycus, Laurencia, Osmundea, Palisada and Yuzurua stat. nov.

Molecular phylogenies inferred from rbcL sequences including 39 representative members of the Laurencia complex confirm the four genera currently recognised within the complex: Laurencia sensu stricto, Osmundea, Chondrophycus and the recently described genus Palisada. Furthermore, Palisada poiteaui was resolved as a fifth independent lineage suggesting that the complex is actually composed of five rather than four genera. Palisada poiteaui is the type species of the subgenus Yuzurua, and elevation of this subgenus to generic rank is proposed. This new genus allied strongly with Laurencia s.s. However, the other intergeneric relationships were not well supported, suggesting that rbcL sequences may not have sufficient signal to clarify infrageneric relationships fully within the Laurencia complex.

LAURENCIA MARILZAE SP. NOV. (CERAMIALES, RHODOPHYTA) FROM THE CANARY ISLANDS, SPAIN, BASED ON MORPHOLOGICAL AND MOLECULAR EVIDENCE(1).

Laurencia marilzae Gil-Rodríguez, Sentíes et M.T. Fujii sp. nov. is described based on specimens that have been collected from the Canary Islands. This new species is characterized by distinctive yellow-orange as its natural habitat color, a terete thallus, four pericentral cells per vegetative axial segment, presence of secondary pit-connections between adjacent cortical cells, markedly projecting cortical cells, and also by the presence of corps en cerise (one per cell) present in all cells of the thallus (cortical, medullary, including pericentral and axial cells, and trichoblasts). It also has a procarp-bearing segment with five pericentral cells and tetrasporangia that are produced from the third and fourth pericentral cells, which are arranged in a parallel manner in relation to fertile branchlets. The phylogenetic position of this taxon was inferred based on chloroplast-encoded rbcL gene sequence analyses. Within the Laurencia assemblage, L.marilzae formed a distinctive lineage sister to all other Laurencia species analyzed. Previously, a large number of unique diterpenes dactylomelane derivatives were isolated and identified from this taxon. L.marilzae is morphologically, genetically, and chemically distinct from all other related species of the Laurencia complex described.

Proposals for Palisada poiteaui var. gemmifera comb. nov. and Palisada corallopsis comb. nov. (Rhodomelaceae, Rhodophyta)

Abstract Since Chondrophycus poiteaui var. gemmiferus and C. corallopsis fall within the new recently validated segregate genus Palisada K.W. Nam, two new nomenclatural combinations are proposed: Palisada poiteaui var. gemmifera and P. corallopsis.

Molecular evidence for Chondrophycus poiteaui var. gemmiferus comb. et stat. nov. (Ceramiales, Rhodophyta) from the Mexican Caribbean Sea: implications for the taxonomy of the Laurencia complex

Abstract Molecular studies were carried out on Chondrophycus gemmiferus and C. poiteaui (Rhodomelaceae) from the Mexican Caribbean Sea. These species are morphologically related, but differ mainly in the presence of the apiculate projection of epidermal cells near the apices of branches. Both species belong to Chondrophycus, as indicated by the presence of two periaxial cells per axial segment and a 90° arrangement of tetrasporangia, but share characteristics with Laurencia species (e.g., presence of secondary pit connections between adjacent epidermal cells). The phylogenetic position of these species was inferred by an analysis of chloroplast-encoded rbcL gene sequences of 21 taxa, using two members of the Rhodomelaceae and two of the Ceramiaceae as outgroups. The results corroborate the taxonomy of the Laurencia complex, which comprises the genera Laurencia, Chondrophycus and Osmundea, and indicate that rbcL provides an adequate phylogenetic signal to study the intergeneric and interspecific relationships within the complex. In spite of this, relationships within the clade formed by C. gemmiferus and C. poiteaui were not resolved by any analysis because of the low level of genetic variation between their rbcL sequences (0.01–0.02%). On the basis of both molecular data and morphological similarities, we concluded that C. gemmiferus should be considered as a variety of C. poiteaui and the following new combination is proposed: Chondrophycus poiteaui var. gemmiferus (Harvey) comb. et stat. nov.

Validation of the Generic Name Palisada (Rhodomelaceae, Rhodophyta)

The name Palisada, which recently was proposed but not validly published for a new genus in the Laurencia complex,is validated by the provision of a Latin diagnosis. Relevant omenclatural changes for several species of Chondrophycus are included.

The species of Chondrophycus and Laurencia (Rhodomelaceae, Ceramiales) occurring in Dhofar, the Sultanate of Oman

M.J. Wynne, D. Serio, M. Cormaci, and G. Furnari. 2005. The species of Chondrophycus and Laurencia (Rhodomelaceae, Ceramiales) occurring in Dhofar, the Sultanate of Oman. Phycologia 44: 497–509.Fieldwork carried out in the Dhofar region of the Sultanate of Oman has resulted in many collections of marine algae assignable to the related genera Chondrophycus and Laurencia. Observations are made on the following five species of Chondrophycus, all representing first reports for Oman: Chondrophycus ceylanicus (J. Agardh) M.J. Wynne, Serio, Cormaci & G. Furnari comb. nov., C. cruciatus, C. dotyi, C. palisadus, and C. succisus. A first record of Laurencia nidifica is made for Oman, and new collections are documented for the previously reported species L. heteroclada and L. majuscula. A key to the Sultanate of Oman species of the Laurencia complex is given.

The Laurencia complex (Rhodophyta, Rhodomelaceae) in the Mediterranean Sea: an overview

Abstract Recent taxonomic studies of the genus Laurencia sensu lato (Ceramiales, Rhodomelaceae) have resulted in the recognition of three genera within the ‘Laurencia complex’: Laurencia sensu stricto, Chondrophycus and Osmundea. A critical examination of all Mediterranean records of taxa referred to Laurencia has shown that three species of Chondrophycus, six species of Osmundea and nine species of Laurencia are present. These taxa are described and illustrated. Laurencia caduciramulosa and L. intricata are reported for the first time from the Mediterranean Sea and from Italy, respectively. A key to the Mediterranean species of the Laurencia complex is given.

Morphology of Chondrophycus undulata and C. parvipapillata and its implications for the taxonomy of the Laurencia (Ceramiales, Rhodophyta) complex

Laurencia Lamouroux subgenus Chondrophycus Tokida et Saito was recently raised to generic status as Chondrophycus (Tokida et Saito) Garbary et Harper (Ceramiales, Rhodophyta). The previously unknown morphology and anatomy of two Chondrophycus species, C. undulata (Yamada) Garbary et Harper and C. parvipapillata (C.K. Tseng) Garbary et Harper, were studied in specimens from Korea, Japan and Hawaii. These species share some features, such as a strongly compressed thallus, vegetative axes with two pericentral cells, tetrasporangial production from pericentral cells and spermatangial development of the trichoblast type. However, they differ from each other in the position of the first pericentral cell relative to the trichoblast in axial segments and in the position of the tetrasporangial pericentral cell. In C. undulata, the first pericentral cell is always produced at one side of the basal cell of a trichoblast, whereas in C. parvipapillata it is formed underneath this cell. While tetrasporangia in C. undulata are produced only from three (occasionally four) additional pericentral cells, in C. parvipapillata they are formed by the existing second pericentral cell and two (occasionally three) additional pericentral cells, so the resulting tetrasporangial axial segment has only one sterile pericentral cell rather than two as in C. undulata. C. undulata produces spermatangial branches from two laterals on the suprabasal cell of trichoblasts but one of the two remains partly sterile, whereas in C. parvipapillata a spermatangial branch develops from only one of the two laterals. These two species also differ distinctly from each other in some vegetative features, such as presence or absence of (1) secondary pit connections between epidermal cells, (2) a palisade structure of epidermal cells with conical projections and (3) corps en cerise. The taxonomic implications of these vegetative and reproductive features of Chondrophycus and those of other genera of the Laurencia complex necessitate changes to the generic delineations of Osmundea Stackhouse, Laurencia and Chondrophycus. The required new combinations in Chondrophycus are made, mainly for species from the western Pacific. An infrageneric classification scheme is also proposed for Chondrophycus including Kangjaewonia subgen. nov., Palisada (Yamada) subgen. stat. nov., Yuzurua subgen. nov. and Parvipapillatae sect. nov.

Morphology of Chondrophycus undulata and C. parvipapillata and its implications for the taxonomy of the Laurencia (Ceramiales, Rhodophyta) complex

Morphology of Chondrophycus undulata and C. parvipapillata and its implications for the taxonomy of the Laurencia (Ceramiales, Rhodophyta) complex

Morphological and molecular evidences within Osmundea (Ceramiales, Rhodophyta) from the Canary Islands, eastern Atlantic Ocean

The genus Osmundea is a strongly supported monophyletic group within the Laurencia complex and shows a disjunct distribution occurring in the North-East and South-West Pacific, the Indian and Atlantic oceans and the Mediterranean Sea. Its phenotypic plasticity on the Canary Islands may be the result of the high ecological variability partially due to the particular oceanographic characteristics in this region. The combination of molecular analyses based on the comparison of the chloroplast-encoded rbcL sequences and morphological data allowed us to delimit three distinct taxa from the coasts of the Canarian Archipelago: Osmundea pinnatifida, Osmundea truncata and an unidentified species, Osmundea sp. Moreover, the high value of genetic divergence between Osmundea sp. and the rest of the Osmundea species suggests that this taxon should be assigned to a new species within the Osmundea genus. Occurrence of O. hybrida and O. oederi (synonym: O. ramosissima) has not been confirmed. Our results also suggest a possibly questionable record of the taxa O. hybrida and O. oederi on the Canary Islands.