Recognition of a new species of Kallymenia (Gigartinales,Rhodophyta) from Croatia (Mediterranean Sea) based on morphology and DNA barcode

The Mediterranean red algal flora is diverse but current knowledge of its diversity is at best fragmentary. Here, a new species of Kallymenia from Croatia is described based on morphological and molecular data. Members of the genus Kallymenia share similar morphology making their generic identification relatively easy, whereas species level identification is notoriously difficult. In this paper an integrative systematics study using three gene markers, cox1 (COI), rbcL and nuclear LSU, allowed us to (i) confirm the identity of four existing members of this genus inhabiting the Mediterranean Sea: K. feldmannii, K. lacerata, K. patens and K. requienii; (ii) detect the presence of K. reniformis only in the Atlantic, and (iii) reveal the presence of a new member of Kallymenia from the Mediterranean Sea, K. ercegovicii Vergés & Le Gall, sp. nov., which is described based on distinctive morphological and molecular characters. Kallymenia ercegovicii is distinguished, using three molecular markers, from all Kallymenia species for which these sequences are available. Morphologically, the new species can be distinguished from other polycarpogonial Kallymenia by a set of characters including a deeply lobed thallus, large inner cortical cells, stellate but non-glanglionic medullary cells and non-ostiolate cystocarps surrounded by a filamentous net composed of elongated cells forming fascicles. An initial phylogeny of the genus Kallymenia was inferred from cox1 (COI), rbcL and nuclear LSU sequences. Kallymenia ercegovicii was resolved with full support within the same lineage as K. reniformis (the generitype), K. feldmannii and K. patens, whereas K. lacerata and K. requienii were only distantly related.     

A rearranged chamigrene derivative and its potential biogenetic precursor from a new species of the marine red algal genus Laurencia (rhodomelaceae)

The structures of a novel rearranged sesquiterpenoid and a biogenetically-related chamigrene derivative have been determined by combined spectral and chemical methods. These sesquiterpenoids were components of an undescribed Laurencia species, and each was toxic toward the damselfish Pomacentrus coeruleus.     

Recent developments in the systematics of the Gigartinaceae (Gigartinales, Rhodophyta) based on rbcL sequence analysis and morphological evidence

The phylogenetic systematics of the Gigartinaceae is discussed for seven genera and three undescribed generic lineages and 65 taxa representing 62 species based on an analysis of rbcL sequences and morphological evidence. An examination of rbcL trees resulting from analyses of these taxa identifies seven lineages: (i) ‘Gigartina’ alveata; (ii) Rhodoglossum/Gigartina; (iii) Chondracanthus; (iv) Ostiophyllum; (v) Sarcothalia; (vi) ‘Gigartina’ skottsbergii; and (vii) a large clade containing Iridaea/‘Sarcothalia’, Mazzaella and Chondrus. These lineages and Chondrus are strongly supported; however, two groups, Iridaea/‘Sarcothalia’ and Mazzaella, receive no bootstrap support. The morphology of the female reproductive system is investigated with the aid of computer-generated, color-coded tracings of photographs of cystocarps seen in cross section at different developmental stages. Seven basic cystocarp types were found which corresponded to species groups seen in rbcL trees. These were: (i) a ‘Gigartina’ alveata group in which the carposporangia-bearing filaments develop apomictically from gametophytic cells; (ii) a Rhodoglossum/Gigartina group in which gonimoblast filaments penetrate the surrounding envelope fusing progessively with envelope cells; (iii) a Chondracanthus group in which gonimoblast filaments penetrate the envelope but fuse with envelope cells only at late developmental stages; (iv) a Sarcothalia group in which the gonimoblast filaments displace an envelope composed mainly of secondary gametophytic filaments and link to envelope cells by terminal tubular gonimoblast cells; (v) an Iridaea group similar to the Sarcothalia group, but with an envelope composed of a mixture of medullary cells and secondary gametophytic filaments; (vi) a Mazzaella group that lacks a true envelope and in which gonimoblast filaments connect to modified gametophytic cells by means of terminal tubular cells; (vii) a Chondrus group in which gonimoblast filaments penetrate the medulla and link to modified medullary cells by means of conjunctor cells forming secondary pit connections. The further separation of these groups into genera is based largely on tetrasporangial characters.     

Sterols of some red algae

The sterol composition of 17 red algae has been determined. Only C-27 sterols have been found in substantial amounts; details of the structural elucidation of liagosterol (cholesta-5,23-diene-3β,25-diol) are given. The possible taxonomic significance of the sterol distribution is briefly discussed.     

Two New Species of the Genus Batrachospermum (Rhodophyta) in China

This paper describes two new species of freshwater red algae, Batrachospermum Roth. They belong to the section Contorta on the basis of their morphological characters. B. curvatum, collected from Hubei Province, is similar to B. tortuosum Kumano, but differs from the latter in shape of whorls, terminal hairs and trichogyne. B. torsivum, collected from Jiangxi Province, resembles B. hirosei Ratnasabapathy et Kumano, but differs from the latter in shape and size of whorls, axial cells, cells of the nodal and internodal filaments, carpogonial branches and trichogyne.     

Green epi-endophytes in Hymenena falklandica (Rhodophyta) from the Patagonian coasts of Argentina: Preliminary observations

The occurrence of epi-endophyte algae in Hymenena falklandica J. G. Ag. Ex Kylin (Rhodophyta) is reported in Argentina. Epicladia heterotricha (Yarish) Nielsen (Chlorophyceae) revealed a 100% prevalence of occurrence, particularly in the basal region of the host. Low (14%), moderate (28%) and high (58%) severity degrees of infection were also registered for E. heterotricha. Pseudendoclonium submarinum Wille (Chlorophyceae) exhibited a lower frequency of occurrence, close to 3%. The developmental morphology and dynamics of E. heterotricha and P. submarinum were investigated under unialgal as well as bialgal culture conditions. The experimental infection of H. falklandica by E. heterotricha demonstrated that E.  heterotricha initially behaves as epiphytic but with endophytic filaments growing into the cortex of the host during late infection. P. submarinum was found to be exclusively epiphytic, with no development of endophytic filamentous systems. The present study reports the first lines of evidence of an epidemiological study conducted with the purpose of comparing both the prevalence and effects of algal epi-endophytic organisms in H. falklandica in the southern coasts of Argentina.     

Carotenogenesis diversification in phylogenetic lineages of Rhodophyta

Carotenoid composition is very diverse in Rhodophyta. In this study, we investigated whether this variation is related to the phylogeny of this group. Rhodophyta consists of seven classes, and they can be divided into two groups on the basis of their morphology. The unicellular group (Cyanidiophyceae, Porphyridiophyceae, Rhodellophyceae, and Stylonematophyceae) contained only β‐carotene and zeaxanthin, “ZEA‐type carotenoids.” In contrast, within the macrophytic group (Bangiophyceae, Compsopogonophyceae, and Florideophyceae), Compsopogonophyceae contained antheraxanthin in addition to ZEA‐type carotenoids, “ANT‐type carotenoids,” whereas Bangiophyceae contained α‐carotene and lutein along with ZEA‐type carotenoids, “LUT‐type carotenoids.” Florideophyceae is divided into five subclasses. Ahnfeltiophycidae, Hildenbrandiophycidae, and Nemaliophycidae contained LUT‐type carotenoids. In Corallinophycidae, Hapalidiales and Lithophylloideae in Corallinales contained LUT‐type carotenoids, whereas Corallinoideae in Corallinales contained ANT‐type carotenoids. In Rhodymeniophycidae, most orders contained LUT‐type carotenoids; however, only Gracilariales contained ANT‐type carotenoids. There is a clear relationship between carotenoid composition and phylogenetics in Rhodophyta. Furthermore, we searched open genome databases of several red algae for references to the synthetic enzymes of the carotenoid types detected in this study. β‐Carotene and zeaxanthin might be synthesized from lycopene, as in land plants. Antheraxanthin might require zeaxanthin epoxydase, whereas α‐carotene and lutein might require two additional enzymes, as in land plants. Furthermore, Glaucophyta contained ZEA‐type carotenoids, and Cryptophyta contained β‐carotene, α‐carotene, and alloxanthin, whose acetylenic group might be synthesized from zeaxanthin by an unknown enzyme. Therefore, we conclude that the presence or absence of the four enzymes is related to diversification of carotenoid composition in these three phyla.     

Sterols of Mediterranean Florideophyceae

The distribution of sterols in 31 Mediterranean Florideophyceae has been investigated. Cholesterol is present in the greatest majority of the species examined, while the occurrence of other C-27 sterols (desmosterol, 22-dehydrocholesterol, liagosterol and cholest-7-en-3β-ol) is much more restricted. Two species (Rytiphloea tinctoria and Vidalia volubilis) contain, in addition to C-27 sterols, large amounts of C-28 and C-29 compounds.     

Simple brominated phenols in red algae

By using TLC and GLC-MS techniques, 23 species of red algae, representing nine orders, were analyzed for the presence of simple bromophenols. Ten bromophenols were detected, five of which might be artefacts. Furthermore, lanosol was identified in sea water from the Polysiphonia Brodiaei—zone. Bromophenols were detected in species from the families Ceramiaceae, Delesseriaceae, Bonnemaisoniaceae, Rhodophyllaceae, Corallinaceae and Rhodomelaceae.     

Rocky shore turfs dominated by Corallina (Corallinales,Rhodophyta) in northern Japan†

Three intertidal sites dominated by Corallina turfs were investigated in Hokkaido, Japan. The sites (A, B and C) differed in slope, wave exposure and length of time exposed to air during tidal cycles. Monthly samples were analyzed for frond morphology and other features. Site A, the most wave-exposed site, was dominated by Corallina sp. X, an unknown species, and sites B and C by Corallina pilulifera Postels et Ruprecht. At the different sites the populations differed in conceptacle abundance, coverage by epiphytic Titanoderma corallinae (P. Crouan et H. Crouan) Woelkerling, Chamberlain et Silva, amount of contained sediment, numbers of axes per quadrat, numbers of branch fusions, branch entanglement, frond dryweight, frond length, amount of adventitious branching, numbers of epiphytes (exclusive of T. corallinae), and numbers of animal species. Ninety-one animal species were recorded from the turfs. Corallina is affected morphologically by conditions inherent in its microhabitat, including desiccation, epiphyte loading and the abundance of herbivores.     

Partial structure and properties of the ferredoxin from Rhodymenia palmata

A ferredoxin of MW 11 000 was isolated from the marine alga Rhodymenia palmata (Palmaria palmata). In its oxidised form the ferredoxin had absorption maxima at 276, sh 281, 328, 423 and 465 nm, and contained a single [2Fe-2S] cluster. The midpoint potential of the ferredoxin was ?400 mV and it effectively mediated electron transport in NADP⁺-photoreduction by higher plant chloroplasts, and pyruvate decarboxylation by the phosphoroclastic system of an anacrobic bacterium. The amino acid composition was Lys₃, His₁, Arg₁, Asx₁₂, Thr₉, Ser₈, Glx₁₃, Pro₄, Gly₈, Ala₇, Cys₅, Val₈, Ile₄, Leu₉, Tyr₄, Phe₂; tryptophan and methionine were absent from the molecule. The N-terminal amino acid region consisting of ca half the total amino acid sequence was determined using an automatic sequencer.     

Morphological and taxonomic studies on some little-known species of Gracilaria (Gracilariales: Rhodophyta) from Venezuela. 1. G. damaecornis

The morphology, anatomy and reproduction (tetrasporic, male and female) of a poorly known species of Gracilaria i.e. G. damaecornis J. Agardh was studied, using material collected in eastern Venezuela. Spermatangia are produced in well-defined and deeply immersed multicavitied conceptacles (m type). Nutritive filaments are present both at the floor and top (outer pericarp) of the cystocarp. The lectotype of G. damaecornis is illustrated for the first time. Hydropuntia albornozii (Rodríguez) Wynne (Polycavernosa albornozzi) is shown to be a synonym of G. damaecornis. In agreement with recent research, it is concluded that generic attributes of Hydropuntia ( = Polycavernosa) based on mainly on sexual reproductive structures are of doubtful taxonomic value.     

Stucture and reproduction of Cordylecladia guiryi sp. nov. (Rhodophyta,Rhodymeniales) from the Mediterranean Sea

Abstract

Cordylecladia guiryi sp. nov. is described from the Mediterranean Sea, after a comparison of habit, morphology and reproduction with C. erecta, the only species of the genus. The species is characterized by the small dimension of its axes which arise single from the basal crust and by its habitat, growing epiphytically on Posidonia oceanica Delile leaves. Tetrasporangial and gametangial plants as well as the development of the carposporophyte have been studied in detail. The carpogonial branch is 4-celled and it is formed on a supporting cell that also bears a 3-celled auxiliary branch. Tetrasporangia are cruciately divided. The reproductive details confirm Sparling's view about the great variation existing in the organization of the procarp in members of this order.     

Genes encoding phycobilisome linker polypeptides on the plastid genome of Aglaothamnion neglectum (Rhodophyta)

The genes encoding the phycobilisome anchor protein (apcE) and rod-core linker (cpcG) are on the plastid genome of the red alga Aglaothamnion neglectum. The apcE gene product is 5 to and in the same operon as the and subunit genes of allophycocyanin. This arrangement is identical to the arrangement observed in many cyanobacteria. The cpcG gene product is 5 to the operon encoding the and subunits of phycoerythrin, but is transcribed from the opposite DNA strand. This gene arrangement is different from that observed in cyanobacteria.The amino acid sequences of the A. neglectum anchor protein and rod-core linker polypeptide, as deduced from the nucleotide sequences of the genes, are approximately 50% identical to analogous polypeptides from cyanobacteria and another eukaryotic alga Cyanophora paradoxa. The conserved nature of these proteins suggests that the structure of the core and the rod-core interface are very similar in phycobilisomes of cyanobacteria and eukaryotic red algae.     

Gracilaria corallicola and G. multipartita (Gracilariales,Rhodophyta), two related flattened European species

Two European species of Gracilaria possess flattened blades borne on cylindrical axes, namely, G. multipartita, known primarily from the Atlantic coast, and G. corallicola from the Mediterranean Sea. They are sister species that cluster with G. armata, G. bursa-pastoris and G. longa in rbcL analyses with strong bootstrap support. Blades of G. multipartita taper towards the tips, whereas those of G. corallicolla have broadly rounded tips. Spermatangia of G. corallicola are borne in shallow conceptacles (textorii-type) and data from the literature indicate that the same is true of G. multipartita. Cystocarp morphology is similar, with the gonimoblast filaments initially elongated, narrow and densely filled with cytoplasm, and with tubular nutritive cells issuing initially from lower gonimoblast cells and fusing with cells in the lowermost regions of the outer pericarp. Tetrasporangia are initiated terminally and displaced laterally with the production of side branches from the subterminal cell. The diagnostic characters of the Gracilariaceae are reviewed from a developmental perspective.     

Ultrastructure of the differentiating zygotospores of Porphyra leucosticta (Rhodophyta)

The ultrastructure of zygotosporogenesis is described for the red alga Porphyra leucosticta Thuret. Packets of eight zygotosporangia, each packet derived from a single carpogonium are interspersed among vegetative cells. Zygotospore differentiation in Porphyra can be separated into three developmental stages. (i) Young zygotospores exhibit a nucleus and a large centrally located, lobed plastid with pyrenoid. Mucilage is produced within concentric membrane structures during their dilation, thus resulting in the formation of mucilage sacs. Subsequently, these sacs release their contents, initiating the zygotospore wall formation. Straight‐profiled dictyosomes produce vesicles that also provide wall material. During the later stages of young zygotospores, starch polymerization commences, (ii) Medium‐aged zygotospores are characterized by the presence of fibrous vacuoles. These are formed from the ‘fibrous vacuole associated organelles’. The fibrous vacuoles finally discharge their contents. (iii) Mature zygotospores are recognized by the presence of numerous cored vesicles produced by dictyosomes. Cored vesicles either discharge their contents or are incorporated into the fibrous vacuoles. There is a gradual reduction of starch granules during zygotospore differentiation. Mature zygotospores are surrounded by a fibrous wall, have a large chloroplast with pyrenoid and well‐depicted phycobilisomes but are devoid of starch granules.     

GABA-mimetic molecules from Porphyra (Rhodophyta) induce metamorphosis of Hafotis (Gastropods) larvae

Tropical littoral Cladocera with special reference to Alona incredibilis sp. nov. and Alonella brasiliensis Bergamin, 1935 from the Amazon basin, are commented upon.     

The cell wall chemistry of Bangia atropurpurea (Bangiales, Rhodophyta) and Bostrychia moritziana (Ceramiales, Rhodophyta) from marine and freshwater environments

The cell wall polysaccharides of two species of red algae, which are adapted to both freshwater and marine environments, were analysed to determine the effect of these widely different environments on their commercially important agarocolloids and to investigate the possible role of the cell wall in environmental adaptation. Cell wall polymers of freshwater isolates of Bangia atropurpurea (Roth) C. Agardh and cultured freshwater and marine Bostrychia moritziana (Sonder ex Kützing) J. Agardh were isolated and the polysaccharides chemically fractionated and characterized. Wall polysaccharides of freshwater B. atropurpurea were similar to those previously reported for marine isolates with repeating disac-charide units of agarose and porphyran predominant in the hot water extracts. In the insoluble residues, 3-iinked galactosyl and 4-linked mannosyl residues were predominant. Bostrychia moritziana wall polysaccharides included agarocolloids with various patterns of methyl ether substitution similar to those previously described for other Ceramiales. Differences in the position of methyl ether substituents were detected in the hot water extracts of the freshwater and marine specimens. Polymers of freshwater ß. moritziana cultures were composed of a complex mixture of repeating disaccharide units including 2′-O-methyl agarose, 6-O-methyI agarose and 2′-O-methyl porphyran. Polymers of marine isolates of ß. moritziana differ in that they contain only trace amounts of 2-O-methyl saccharides and increased amounts of 6-O-amethyl saccharides. The hot water insoluble residues of both freshwater and marine isolates of ß. moritziana contain a mixture of 3-linked galactosyl and 4-linked glucosyl residues. These results indicate that the adaptive response of B. moritziana to changing osmotic and ionic conditions may include changes in cell wall chemistry: notably, the pattern of methyl ether substitution.     

Characterization and transcript analysis of the major phycobiliprotein subunit genes from Aglaothamnion neglectum (Rhodophyta)

The genes encoding the and subunits of allophycocyanin, phycocyanin and phycoerythrin from the red alga Aglaothamnion neglectum were isolated and characterized. While the operons containing the different phycobiliprotein genes are dispersed on the plastid genome, the genes encoding the and subunits for each phycobiliprotein are contiguous. The subunit gene is 5 for both the phycocyanin and phycoerythrin operons, while the subunit gene is 5 for the allophycocyanin operon. The amino acid sequences of A. neglectum phycobiliproteins, as deduced from the nucleotide sequences of the genes, are 65–85% identical to analogous proteins from other red algae and cyanobacteria. The conserved nature of the plastid-encoded red algal and cyanobacterial phycobiliprotein genes supports the proposed origin of red algal plastids from cyanobacterial endosymbionts.Many environmental factors effect phycobilisome biosynthesis. The effect of both nutrient availability and light quantity on the level of A. neglectum phycobiliprotein subunits and the mRNA species encoding those subunits is described.