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At least 19 recordsLinked to original sources
PubMed1994

A gene phylogeny of the red algae (Rhodophyta) based on plastid rbcL.

A phylogeny for the Rhodophyta has been inferred by parsimony analysis of plastid rbcL sequences representing 81 species, 68 genera, 38 families, and 17 orders of red algae; rbcL encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Levels of sequence divergence among species, genera, and families are high in red algae, typically much greater than those reported for flowering plants. The Rhodophyta traditionally consists of one class, Rhodophyceae, and two subclasses, Bangiophycidae and Florideophycidae. The Bangiophycidae with three orders (Porphyridiales, Compsopogonales, and Bangiales) appears to be polyphyletic, and the Florideophycidae with 17 orders is monophyletic in this study. The current classification of the Florideophycidae based on ultrastructure of pit connections is supported. With the exception of the Rhodogorgonales, which appears to be misplaced, orders with one or two pit-plug cap layers (Hildenbrandiales, Corallinales, Acrochaetiales, Palmanales, Batrachospermales, and Nemaliales) terminate long branches of basal position within Florideophycidae in the most parsimonious rbcL tree. Orders that lack typical cap layers but possess a cap membrane are resolved as a monophyletic clade sister to the Ahnfeltiales. The large order Gigartinales, which is distributed among five rbcL clades, is polyphyletic. Families that possess typical carrageenan in their cell walls are resolved as a terminal clade containing two family complexes centered around the Solieriaceae and Gigartinaceae.

Molecular Sequence Data↗
PubMed1990

Rubisco genes indicate a close phylogenetic relation between the plastids of Chromophyta and Rhodophyta.

The genes for both subunits of Rubisco (rbcL, rbcS) are located on the plastome of the brown alga Ectocarpus siliculosus (Chromophyta, Phaeophyceae). The organization of these genes in the form of an operon was similar to that found in rhodoplasts, cyanobacteria and the plastids of Cryptomonas phi. Sequence analysis of the complete operon revealed a high degree of homology and great structural similarities to corresponding genes from two red algae. In contrast, sequence homology to Rubisco genes from chloroplasts and cyanobacteria was much lower. This clearly indicated a close phylogenetic relationship between the plastids of Rhodophyta and Chromophyta which seem to have evolved independently from the chloroplasts (polyphyletic origin). Our data suggest that the plastids of Chromophyta and Cryptophyta have originated from endosymbiotic unicellular red algae. Surprisingly, red and brown algal Rubiscos show a significantly higher degree of homology to that from a hydrogen bacterium than to those from cyanobacteria.

Amino Acid Sequence↗
PubMed1993

psbD sequences of Bumilleriopsis filiformis (Heterokontophyta, Xanthophyceae) and Porphyridium purpureum (Rhodophyta, Bangiophycidae): evidence for polyphyletic origins of plastids.

The nucleotide sequences of the plastidal psbD genes of Bumilleriopsis filiformis and Porphyridium purpureum (encoding the D2 protein of photosystem II) are reported in this paper. The Bumilleriopsis sequence clusters together with Porphyridium when a most parsimonious protein tree of D2 sequences is constructed. A composite D1/D2 protein-similarity network reveals that neither the three red algal sequences nor the two heterokontophyte sequences (Bumilleriopsis, xanthophytes and Ectocarpus, phaeophytes) group together. Therefore, the Heterokontophyta and Rhodophyta may be heterogeneous groups. Instead, it emerges that the D1/D2 proteins of Porphyridium and Bumilleriopsis clearly form a tight cluster. D1 and D2 proteins apparently do not provide a reliable molecular clock. These results fit into hypotheses proposing a polyphyletic origin for complex plastids, even among the supposedly "natural" group of heterokontophytes.

Base Sequence↗
PubMed2005

Visualization of DNA-containing structures in various species of Chlorophyta, Rhodophyta and Cyanophyta using SYBR Green I dye.

We developed an alternative method of staining cell nuclei and chloroplast nucleoids of algal cells using SYBR Green I (the fluorescent dye used commonly for detecting dsDNA in agarose and polyacrylamide gels as an alternative to highly mutagenic ethidium bromide and for DNA staining of viruses and bacteria followed by flow cytometry, digital image analysis or real-time PCR), which enabled routine staining in vivo. Cells do not need to be fixed or treated chemically or physically before staining, thus the shape, size and position of DNA-containing structures are not affected. The fluorescence signal is sharp and reproducible. Examples of application of the method are shown in color microphotographs for representatives of eukaryotic algae from the taxa Chlorophyta, Rhodophyta and the prokaryotic Cyanophyta. The method is also useful for studying progress of the cell cycle in algal cells dividing by multiple fission, as shown by observation of changes in nuclear number during the cell cycle of the green alga Chlamydomonas reinhardtii and Scenedesmus quadricauda. Staining with SYBR Green I can be recommended as a fast, safe and efficient method for the detection of DNA-containing structures in vivo.

Benzothiazoles↗
PubMed2026

Phylogenomics and female reproductive morphology reframe the classification of the Halymeniales (Rhodophyta).

The red algal order Halymeniales (Rhodophyta) exhibits remarkable morphological and taxonomic diversity but its higher-level relationships remain poorly resolved. Here, we present a comprehensive phylogenomic analysis based on newly generated plastid (170 protein-coding genes), mitochondrial (23 genes), and complete nuclear ribosomal cistron sequences from 56 taxa, complemented with an expanded rbcL dataset encompassing 334 sequences. Our results provide a robust phylogenomic framework for the Halymeniales, offering a taxonomic backbone for future systematic studies. The analyses consistently recover six early-diverging lineages (Acrodiscus, Isabbottia, Norrissia, Pachymenia, Zymurgia, and Tsengia) and two strongly supported larger clades (Halymenia s.l. and Grateloupia s.l.). While most small and recently described genera are monophyletic, several traditional genera (e.g., Halymenia, Cryptonemia, Grateloupia) are poly- or paraphyletic, requiring considerable taxonomic revision. At the family level, the data indicate that reinstatement of the Grateloupiaceae sensu Kim et al. (2021) would entail a revised circumscription of the Halymeniaceae and the recognition of at least five small families to accommodate the early-diverging lineages. Although such a revised classification would result in monophyletic families, it is not supported by morpho-anatomical characters. Instead, we propose a more stable two-family system, recognizing a broadly circumscribed Halymeniaceae that is sister to the Tsengiaceae. Female reproductive characters, particularly the structure of carpogonial and auxiliary cell ampullae, support this two-family system and further characterize many genus-level clades, although substantial convergence across lineages exists.

Phylogeny↗
PubMed1994

A molecular phylogeny of the marine red algae (Rhodophyta) based on the nuclear small-subunit rRNA gene.

A phylogeny of marine Rhodophyta has been inferred by a number of methods from nucleotide sequences of nuclear genes encoding small subunit rRNA from 39 species in 15 orders. Sequence divergences are relatively large, especially among bangiophytes and even among congeners in this group. Subclass Bangiophycidae appears polyphyletic, encompassing at least three lineages, with Porphyridiales distributed between two of these. Subclass Florideophycidae is monophyletic, with Hildenbrandiales, Corallinales, Ahnfeltiales, and a close association of Nemaliales, Acrochaetiales, and Palmariales forming the four deepest branches. Cermiales may represent a convergence of vegetative and reproductive morphologies, as family Ceramiaceae is at best weakly related to the rest of the order, and one of its members appears to be allied to Gelidiales. Except for Gigartinales, for which more data are required, the other florideophyte orders appear distinct and taxonomically justified. A good correlation was observed with taxonomy based on pit-plug ultrastructure. Tests under maximum-likelihood and parsimony of alternative phylogenies based on structure and chemistry refuted suggestions that Acrochaetiales is the most primitive florideophyte order and that Gelidiales and Hildenbrandiales are sister groups.

Base Sequence↗
PubMed2000

Infectious diseases in Mazzaella laminarioides (Rhodophyta): estimating the effect of infections on host reproductive potential.

Very little is known about the potential effects of endophytic infections on the host in algae, especially in terms of fitness. In this study, we report a first attempt at quantifying the effects of the endophytes Endophyton ramosum (Chlorophyta) and Pleurocapsa sp. (Cyanophyta) on the reproductive potential of their host Mazzaella laminarioides (Rhodophyta). Density of reproductive structures and spore germination rates was compared between infected and non-infected fronds. It was found that differences in density of reproductive structures between infected and non-infected fronds were not significant, which suggests that the level of maturity of the host is unaltered by the endophytes. On the other hand, carpospore germination rates significantly decreased when produced by fronds infected by the cyanobacterium Pleurocapsa sp. Thus, in the general context of host fitness, we discuss the fact that only some of the components of the reproductive output of M. laminarioides are negatively affected by the endophytes.

Chlorophyta↗
PubMed2000

Phylogeny of the Bangiophycidae (Rhodophyta) and the secondary endosymbiotic origin of algal plastids.

The Rhodophyta (red algae) are composed of the subclasses Bangiophycidae and Florideophycidae. Two evolutionarily interesting features of the Bangiophycidae are: (1) they are the ancestral pool from which the more morphologically complex taxa in the Florideophycidae have arisen and (2) they are the sources of the plastids, through secondary endosymbioses, for the Cryptophyta, Haptophyta, and the Heterokonta. To understand Bangiophycidae phylogeny and to gain further insights into red algal secondary endosymbioses, we sequenced the plastid-encoded small subunit ribosomal DNA (rDNA) coding region from nine members of this subclass and from two members of the Florideophycidae. These sequences were included in phylogenetic analyses with all available red algal plus chlorophyll a + c algal plastid rDNA coding regions. Our results are consistent with a monophyletic origin of the Florideophycidae with these taxa forming a sister group of the Bangiales. The Bangiophycidae is of a paraphyletic origin with orders such as the Porphyridiales polyphyletic and distributed over three independent red algal lineages. The plastids of the heterokonts are most closely related to members of the Cyanidium-Galdieria group of Porphyridiales and are not directly related to cryptophyte and haptophyte plastids. The phylogenies provide strong evidence for the independent origins of these "complex" algal plastids from different members of the Bangiophycidae.

Journal Article↗
PubMed1993

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

The genes encoding the alpha and beta 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 alpha and beta subunits for each phycobiliprotein are contiguous. The beta subunit gene is 5' for both the phycocyanin and phycoerythrin operons, while the alpha 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.

Amino Acid Sequence↗
PubMed1995

Structural features and phylogeny of the actin gene of Chondrus crispus (Gigartinales, Rhodophyta).

We have characterized the cDNA and genomic sequences that encode actin from the multicellular red alga Chondrus crispus. Southern-blot analysis indicates that the C. crispus actin gene (ChAc) is present as a single copy. Northern analysis shows that, like the GapA gene, the actin gene is well expressed in gametophytes but weakly in protoplasts. Compared to actin genes of animals, fungi, green plants and oomycetes, that of C. crispus displays a higher evolutionary rate and does not show any of the amino-acid signatures characteristic of the other lineages. As previously described for GapA, ChAc is interrupted by a single intron at the beginning of the coding region. The site of initiation of transcription was characterized by RNAse protection. The promoter region displays a CAAT box but lacks a canonical TATA motif. Other noticeable features, such as a high content of pyrimidines as well as a 14-nt motif found in both the 5'-untranslated region and the intron, were observed.

Actins↗
PubMed1976

Unusual cell structures in tumor-like formations of Gracilaria (Rhodophyta).

This paper deals with electron microscopic observations on cultivated plants of the marine red alga Gracilaria verrucosa which developed simple galla; also sea collected material, without galls, had been studied. The galls showed unusual but characteristic cell structured, caterpillar-like bodies, containing rows of fusiform bodies. These were found mostly in the cytoplasm near the plastids, in one case connected with the endoplasmic reticulum, occasionally even inside the nucleus, and are described here, as far as we know, for the first time. It does not seem probably that the caterpillar-like bodies represent mitochondria or bacteria, but the hypothesis that fusiform bodies are related to virus-like structures is discussed. The normal tissues as well as the gall tissue of the laboratory plants contained, besides plastids typical for the red algae, another type of plastids characterized by tubular thylakoids.

Cytoplasmic Granules↗
PubMed2001

Potassium drives daily reversible thallus enlargement in the marine red alga Porphyra leucosticta (Rhodophyta).

Growth rate in terms of area expansion per 30 min was measured in the marine red algae Porphyra leucosticta under light/dark cycles of 6:6 h. Thalli grown in artificial seawater (ASW), under controlled ionic concentrations, showed a rapid thallus expansion just after light-on (morning-peak). Dark phase began with a significant thallus contraction (dark-peak) but no growth was observed until the next light phase. The removal of K+ from the medium inhibited the reversible growth peak that this species shows after light-on. On the other hand, the removal of Na+ did not have an apparent effect on growth pattern. Addition of Rb+ to K+-free ASW restored the morning-peak to 60% of its value in ASW, but addition of Li+ failed to restore the morning-peak. Intracellular ion analyses revealed that after light-on, the internal K+ content of the cells of this species increased 4-fold in 90 min, reaching an intracellular concentration of up to 300 micromol K+ per gram fresh weight, and that this value remained fairly constant over the light phase. Addition of 100 mM of tetraethylammonium, a specific K+-channel blocker, inhibited the morning-peak by 40%. The Na+ and Cl- contents in the cells increased rapidly in the first 45 min of the light phase, but then the internal concentrations of both ions decreased to their minimum values in the light phase. The carbonic anhydrase inhibitors acetazolamide and 6-ethoxyzolamide did not affect thallus expansion during the light phase. In contrast, thallus expansion in the light phase was completely inhibited by diethylstilbestrol, an inhibitor of the putative primary pump, and by 3-(3',4'-dichlorophenyl)-1,1-dimethylurea (DCMU), an inhibitor of photosynthesis, but not by sodium vanadate, a specific inhibitor of the plasma-membrane H+-ATPase. We suggest that the periodic oscillation of the short-term growth rate of P. leucosticta occurs in response to potassium fluxes, which control the osmotic pressure and eventually the relative cell volume. The possible effects of the loosening of the cell wall and the internal K+ concentration on the growth of this species are also discussed.

Acetazolamide↗
PubMedDate not supplied

UV-absorbing substance in the red alga Porphyra yezoensis (Bangiales, Rhodophyta) block thymine photodimer production.

The effect of the water-soluble UV-absorbing substance (UVAS) extracted from the marine red alga Porphyra yezoensis Ueda on UV-dependent thymine photodimer production was investigated. The T<>T pyrimidine-pyrimidone 6-4 dimer and the cyclobutane cis-syn T<>T 5-6 dimer produced by UV irradiation with a xenon lamp were analyzed by reverse-phase high-performance liquid chromatography. Although the dimer production was reduced when the irradiation was filtered through a UVAS solution, it decreased more when thymine was mixed with UVAS. Furthermore, UVAS inhibited the degradation of UV-irradiated thymine. The inhibitory effect of UVAS was significantly greater than that of exogenously added adenine or guanine, which forms complementary base pairs with thymine. These data suggest that in addition to its filtering effect against UV radiation, UVAS also protects thymine by a direct molecule-to-molecule energy transfer process. The protective function of UVAS against UV irradiation is advantageous for this alga under strong UV irradiation.

Absorption↗
PubMed2004

Speciation and biogeography of the Caloglossa leprieurii complex (Delesseriaceae, Rhodophyta).

Studies on the morphology, reproductive compatibility, life cycle and molecular phylogeny of the euryhaline red alga Caloglossa provide insights into the speciation events and biogeographic patterns. The C. leprieurii complex is separated into three morphotypes based on the number of cell rows at nodes and the blade width. The three morphotypes are reproductively incompatible with each other, and furthermore many mating groups are recognized within the morphotypes. Incomplete reproductive isolation is occasionally seen between geographically distant mating groups, whereas no sexual compatibility occurs between sympatrically or parapatrically distributed mating groups. In the molecular phylogenetic analyses, the C. leprieurii complex is resolved as two clusters that phenotypically correspond to the single and multiple cell row types, respectively. The strains belonging to the same mating group are closely related to each other, without exception, while the mating groups showing incomplete reproductive reactions do not always make a clade. The genetic distance is generally not correlative to the geographic distance, and this is also suggested by the morphological data and crossability. These results indicate that allopatric speciation has frequently occurred in this species complex, although there is some evidence of long-distance dispersal.

Brazil↗
PubMed2005

Comparative study of carrageenans from reproductive and sterile forms of Tichocarpus crinitus (Gmel.) Rupr (Rhodophyta, Tichocarpaceae).

A comparative study of the structure and properties of the sulfated polysaccharides (carrageenans) isolated from the vegetative and reproductive forms of the red alga Tichocarpus crinitus was performed. The polysaccharides were separated into the gelling (KCl-insoluble) and non-gelling (KCl-soluble) fractions by precipitation with 4% KCl. The total content of polysaccharides extracted from the reproductive form of the alga was 1.8-fold more than that extracted from the vegetative form, and in the first case, the gelling polysaccharides mostly accumulated. The gelling polysaccharides from the vegetative form have the highest molecular weight (354 kD). According to the results of FT-IR and 13C-NMR spectroscopy, the gelling polysaccharide fractions from both forms are kappa/beta carrageenans. The differences concern the content of the kappa- and beta-disaccharide units and the presence of a small content of the sulfated disaccharide segments (precursors of the kappa-carrageenans) in the polysaccharide from the reproductive form of the alga. The non-gelling polysaccharide fractions from both forms of the plant are mixtures of sulfated galactans with a low content of 3,6-anhydrogalactose.

Carrageenan↗
PubMed1994

Carrageenan from the tetrasporic stage of Gigartina decipiens (Gigartinaceae, Rhodophyta).

The structure of the polysaccharide isolated from tetrasporophytic plants of the New Zealand red alga Gigartina decipiens has been determined by chemical and spectroscopic techniques. It is a linear polymer composed primarily of alternating 3-linked beta-D-galactopyranosyl 2-sulphate and 4-linked alpha-D-galactopyranosyl 2,6-disulphate residues. About 15% of the 3-linked residues have an additional sulphate ester group at the 6-position. Aside from this small extra sulphate substitution, the structure is that of the idealised lambda-carrageenan. Good quality solution-state 13C NMR spectra were recorded and interpreted for this carrageenan and for the carrageenans produced from it by solvolytic desulphation and alkali modification.

Carbohydrate Sequence↗
PubMed1990

Cyanobacteria or rhodophyta? Interpretation of a precambrian microfossil.

Discovery and interpretation of a filamentous microfossil from the late Proterozoic Narssârssuk Formation in northwest Greenland approximately 770 Ma is reported here. This microfossil is preserved as a single occurrence in a silicified carbonate sequence containing stromatolitic laminae. Based on the absence of other occurrences and its microstratigraphic association with planktonic microfossils, the microfossil is interpreted as allochthonous. The microfossil is similar to two extant taxa representing different kingdoms: one prokaryote, Johannesbaptistia pellucida (cyanobacteria) and one eukaryote, Bangia sp. (rhodophytes). Definitive identification, due to the lack of distinctive morphology, could not be made.

Cyanobacteria↗