Red Alga Porphyra Research Articles

Novel species of the oomycete Olpidiopsis potentially threaten European red algal cultivation

The rapid growth of marine macroalgal cultivation amplifies the potential impacts of seaweed diseases. Here, we combine microscopy and molecular analysis to describe two novel European species, Olpidiopsis palmariae and O. muelleri spp. nov., that infect the commercially important red algae Palmaria and Porphyra, respectively. A Scottish variety of Olpidiopsis porphyrae, a devastating pathogen of Pyropia previously thought to be restricted to Japanese seaweed farms, is also described as O. porphyrae var. scotiae. In the light of their destructiveness in Asian farms, together with the global expansion of algal cultivation and pertaining seed trade, Olpidiopsis pathogens should be treated as a serious threat to the sustainability of red algal aquaculture. Our findings call for the documentation of seaweed pathogens and the creation of an international biosecurity framework to limit their spread.

A pilot study of genetic structure of Porphyra umbilicalis K\xfctzing in the Gulf of Maine using SNP markers from RNA-Seq

The red alga Porphyra umbilicalis Kützing has a broad distribution within the North Atlantic. In the Northeast Atlantic, P. umbilicalis is dioecious and reproduces both sexually and asexually, while in the Northwest Atlantic, only asexual reproduction has been observed. In this study, transcriptomes were mined to identify putative single nucleotide polymorphisms (SNP) markers. A computational pipeline was developed that accounts for the specific characteristics of transcriptome dataset, filtered against the available red alga Chondrus genome and P. umbilicalis EST library to eliminate microbial contamination. Five hundred forty-nine putative SNPs were detected within a single population (Schoodic Point, ME, USA). Five of the validated SNP markers were applied in a pilot study of genetic diversity and population structure of seven P. umbilicalis populations within the Gulf of Maine. Results of this study revealed the genetic diversity and structure of P. umbilicalis populations in the Gulf of Maine. Novel genotypes were found in the open coastal populations at Reid State Park, Schoodic Point, and the estuarine tidal rapid population at Wiscasset. Our study represents the first attempt to develop suitable bioinformatic pipeline for RNA-seq to detect SNP markers for red alga Porphyra umbilicalis and successfully used these SNP markers for population study.

Analytical pyrolysis reaction characteristics of Porphyra tenera

The non-isothermal pyrolysis of red algae (Porphyra tenera) was studied via thermogravimetric (TG) analysis in combination with two types of analytical pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS) techniques, namely, evolved gas analysis (EGA)-MS and multi-shot Py-GC/MS. The TG and model-free kinetic analyses revealed that the pyrolysis of P. tenera proceeded via the independent decomposition of carbohydrates, proteins, and lipids. Differential TG and EGA-MS indicated the existence of three decomposition temperature regions. In the first temperature region (<300 °C), carbohydrates were mainly decomposed. Large amounts of pyrolyzates of proteins and lipids such as toluene, phenols, aromatic amino acids, and hexadecanoic acid were produced in the second temperature region (301–380 °C). In the third region (>380 °C), large amounts of aromatic hydrocarbons and alkanes were obtained by the secondary cracking of the pyrolyzates of proteins and lipids.

The PII signaling protein from red algae represents an evolutionary link between cyanobacterial and Chloroplastida PII proteins

PII superfamily consists of widespread signal transduction proteins found in all domains of life. Whereas they are well-studied in Archaea, Bacteria and Chloroplastida, no PII homolog has been analyzed in Rhodophyta (red algae), where PII is encoded by a chloroplast localized glnB gene. Here, we characterized relevant sensory properties of PII from the red alga Porphyra purpurea (PpPII) in comparison to PII proteins from different phyla of oxygenic phototrophs (cyanobacteria, Chlamydomonas and Physcomitrella) to assess evolutionary conservation versus adaptive properties. Like its cyanobacterial counterparts, PpPII binds ATP/ADP and 2-oxoglutarate in synergy with ATP. However, green algae and land plant PII proteins lost the ability to bind ADP. In contrast to PII proteins from green algae and land plants, PpPII enhances the activity of N-acetyl-L-glutamate kinase (NAGK) and relieves it from feedback inhibition by arginine in a glutamine-independent manner. Like PII from Chloroplastida, PpPII is not able to interact with the cyanobacterial transcriptional co-activator PipX. These data emphasize the conserved role of NAGK as a major PII-interactor throughout the evolution of oxygenic phototrophs, and confirms the specific role of PipX for cyanobacteria. Our results highlight the PII signaling system in red algae as an evolutionary intermediate between Cyanobacteria and Chlorophyta.

Isolation and characterization of microsatellite markers for the red alga Porphyra umbilicalis

AbstractThe red algal genus Porphyra is sister to the genus Pyropia, the single most valuable marine crop in the Orient. We developed microsatellite loci for the red alga Porphyra umbilicalis, a widespread species in the Northern Atlantic. Enriched DNA libraries were constructed and 68 loci were screened for amplification and polymorphism. Seven polymorphic microsatellite markers were isolated using 44 individuals collected from four natural populations. The number of alleles per locus ranged from two to 12. Null alleles were detected in three loci. Among the markers reported, we tested also cross-amplification with two other Porphyra spp. These polymorphic microsatellite markers should be useful for investigating population genetic structure of P. umbilicalis in the North East Atlantic.

Effect of sulfated galactan from Porphyra haitanensis on H2O2-induced premature senescence in WI-38 cells

Porphyran sulfated galactan extracted from red algae Porphyra haitanensis is a sulfated polysaccharide, which possesses excellent activities. In the present study, WI-38 cells were treated with H2O2 to induce premature senescence and then the protection of porphyran against aging in vitro and associated molecular mechanisms were investigated. The protection occurred in a dose-dependent manner, offering an optimal efficacy starting at 10μg/mL. The proportion of SA-β-gal positive cells in porphyran group decreases from 53% to 23% in the cultures at 30 PDs. Porphyran has been detected specifically reducing SAHF-like foci formation in senescent cells. In addition, porphyran significantly affected the p53-p21 pathways in H2O2-treated WI-38 cells. Our data suggest the promising role of porphyran as an attractive and bio-safe agent with the potential to retard senescence and attenuate senescence-related diseases.

In vivo antihyperlipidemic and antioxidant activity of porphyran in hyperlipidemic mice

The hypolipidemic and antioxidant effects of porphyran from the red algae Porphyra haitanensis as a dietary supplement were evaluated in mice. The levels of serum TC, TG and LDL-C in MP group increased significantly (p<0.05 or p<0.01) by 28.5%, 29.4% and 33.5% compared with the model group. These significant rises were accompanied by significant declines of plasma HDL-C by 21.6% compared with the model group. In addition, the liver content of malondialdehyde significantly decreased, while the superoxide dismutase, catalase, glutathione peroxidase activities significantly increased. The levels of serum SOD and GSH-Px in MP group increased significantly by 51.2% and 99.6% compared with the model group. The results suggested that porphyran could be used as functional foods and natural drugs in preventing the hyperlipidemia and this activity might be attributed to its antioxidant potential.

Immunomodulatory Effects of the Mycosporine-Like Amino Acids Shinorine and Porphyra-334.

Mycosporine-like amino acids (MAAs) are secondary metabolites, produced by a large variety of microorganisms including algae, cyanobacteria, lichen and fungi. MAAs act as UV-absorbers and photo-protectants. MAAs are suggested to exert pharmaceutical relevant bioactivities in the human system. We particularly focused on their effect on defence and regulatory pathways that are active in inflamed environments. The MAAs shinorine and porphyra-334 were isolated and purified from the red algae Porphyra sp. using chromatographic methods. The effect of MAAs on central signaling cascades, such as transcription factor nuclear factor kappa b (NF-κB) activation, as well as tryptophan metabolism, was investigated in human myelomonocytic THP-1 and THP-1-Blue cells. Cells were exposed to the MAAs in the presence or absence of lipopolysaccharide (LPS). NF-κB activity and the activity of tryptophan degrading enzyme indoleamine 2,3-dioxygenase (IDO-1) were used as readout. Compounds were tested in the concentration range from 12.5 to 200 µg/mL. Both MAAs were able to induce NF-κB activity in unstimulated THP-1-Blue cells, whereby the increase was dose-dependent and more pronounced with shinorine treatment. While shinorine also slightly superinduced NF-κB in LPS-stimulated cells, porphyra-334 reduced NF-κB activity in this inflammatory background. Modulation of tryptophan metabolism was moderate, suppressive in stimulated cells with the lower treatment concentration of both MAAs and with the unstimulated cells upon porphyra-334 treatment. Inflammatory pathways are affected by MAAs, but despite the structural similarity, diverse effects were observed.

Increased algal fouling on mussels with barnacle epibionts: a fouling cascade

If the external surfaces of epibionts are more suitable to other fouling species than those of their basibionts, a ‘fouling cascade’ might occur where epibionts facilitate secondary colonization by other epibionts. Here we evaluate whether the presence of epibiotic barnalces (Balanus glandula) influences the probability of mussel (Brachidontes rodriguezii) fouling by ephemeral red algae (Porphyra sp.) in a Southwestern Atlantic rocky shore. Mussels with barnacle epibionts showed a higher prevalence of Porphyra sp. fouling (32–40% depending on sampling date) than mussels without them (3–7%). Two lines of evidence indicate that barnacles facilitate Porphyra sp. fouling. First, most Porphyra sp. thalli in mussels with barnacle epibionts were attached to barnacle shells (75–92% of cases). Secondly, Porphyra sp. associated with mussels with barnacle epibionts in a proportion that significantly exceeded that expected under random co-occurrence. These results suggest the occurrence of a fouling cascade where barnacle epibiosis on mussels facilitates subsequent algal fouling. Recognizing the occurrence of such fouling cascades is important because they might explain the non-random aggregation of multiple epibiotic species onto a proportionally few individuals of the host species.

Genetic variation within and among asexual populations of Porphyra umbilicalis Kützing (Bangiales, Rhodophyta) in the Gulf of Maine, USA

Abstract The intertidal marine red alga Porphyra umbilicalis reproduces asexually in the Northwest Atlantic. We looked for population substructure among typical open-coastal and atypical estuarine habitats in seven asexual populations of P. umbilicalis from Maine to New Hampshire using eight expressed sequence tag-simple sequence repeats (EST-SSR) or microsatellite loci. Six genotypes were identified, four of which may represent recombinant genotypes from a recombination event that took place locally, or that took place prior to introduction to the Northwest Atlantic. Genotypic diversity was lowest in a population from Wiscasset, Maine, which inhabits an atypical habitat high in the intertidal zone of a bridge piling in an estuarine tidal rapid. Genotypic diversity was highest in the southernmost populations from New Hampshire; we identified two genotypes that were unique to the southernmost populations, and probably represent the most derived genotypes. We looked at genetic distances among populations in similar habitats, and found that populations were more closely related to their closest neighboring population than to a population in a similar habitat. We show that genotypic diversity within P. umbilicalis populations in the Gulf of Maine is relatively high and thus fits a model of high steady-state variation within asexual populations.

The Edible Red Alga Porphyra yezoensis Promotes Neuronal Survival and Cytoarchitecture in Primary Hippocampal Neurons.

The edible red alga Porphyra yezoensis is among the most popular marine algae and is of economic and medicinal importance. In the present study, the neurotrophic and neuroprotective activities of the ethanol extract of P. yezoensis (PYE) were investigated in primary cultures of hippocampal neurons. Results revealed that PYE significantly increased neurite outgrowth at an optimal concentration of 15µg/mL. PYE dose-dependently increased viable cells, significantly accelerated the rate of neuronal differentiation in cultures, promoted axodendritic arborization, and eventually induced synaptogenesis. In addition to morphological development, PYE also promoted functional maturation as indicated by the staining of live cultures with FM 1-43. Moreover, PYE increased neuronal survivability, which was attributed to reduced apoptosis and its ROS scavenging activity. Taurine, a major organic acid in PYE (2.584/100mg of dry PYE) promoted neurite outgrowth in a dose-dependent manner, and this promotion was suppressed by the taurine antagonist isethionic acid. The study indicates that PYE and its active component, taurine, facilitate neuronal development and maturation and have a neuroprotective effect.

Inhibition of Collagenase by Mycosporine-like Amino Acids from Marine Sources.

Matrix metalloproteinases play an important role in extracellular matrix remodeling. Excessive activity of these enzymes can be induced by UV light and leads to skin damage, a process known as photoaging. In this study, we investigated the collagenase inhibition potential of mycosporine-like amino acids, compounds that have been isolated from marine organisms and are known photoprotectants against UV-A and UV-B. For this purpose, the commonly used collagenase assay was optimized and for the first time validated in terms of relationships between enzyme-substrate concentrations, temperature, incubation time, and enzyme stability. Three compounds were isolated from the marine red algae Porphyra sp. and Palmaria palmata, and evaluated for their inhibitory properties against Chlostridium histolyticum collagenase. A dose-dependent, but very moderate, inhibition was observed for all substances and IC50 values of 104.0 µM for shinorine, 105.9 µM for porphyra, and 158.9 µM for palythine were determined. Additionally, computer-aided docking models suggested that the mycosporine-like amino acids binding to the active site of the enzyme is a competitive inhibition.

Ultrasound-assisted extraction and purification of taurine from the red algae Porphyra yezoensis

The present study reports on the development of a method using ultrasound-assisted extraction (UAE) during the purification of taurine from Porphyra yezoensis. The Box–Behnken design, which is a widely used form of response surface methodology, was used to investigate the effects of parameters on the UAE process. Three independent variables of taurine purification using UAE were studied including: extraction time, temperature, and ultrasonic power. The results showed that the highest taurine yield of 13.0mg/g was obtained with an extraction time of 38.3min, the use of 300.0W ultrasonic power, and an extraction temperature of 40.5°C. A comparative study of taurine extraction was also conducted using either ultrasonication or mechanical agitation. The results indicated that the ultrasonic process required 9 times less time at 40°C to obtain taurine with a similar yield as compared to the conventional extraction method. Therefore, UAE can used as an alternative to the conventional extraction method used during the recovery of taurine from P. yezoensis. The UAE method has several advantages, including that it uses lower extraction temperatures and has a shorter extraction time. The taurine present in the extract supernatant was efficiently separated and purified using a combination of 732 cation exchange chromatography and crystallization. The yield of purified taurine using this process was 1.1%. The structure of the purified taurine was confirmed by FTIR, MS, and NMR. Our findings suggest that P. yezoensis can be used as a taurine-rich food or food material.

Metabolite changes during the life history of Porphyra haitanensis.

Plant metabolomics is essentially the comprehensive analysis of complex metabolites of plant extracts. Metabolic fingerprinting is an important part of plant metabolomics research. In this study, metabolic fingerprinting of different stages of the life history of the red alga Porphyra haitanensis was performed. The stages included conchocelis filaments, sporangial branchlets, conchosporangia, discharged conchospores and conchosporangial branchlets after conchospore discharge. Metabolite extracts were analysed with ultra-performance liquid chromatography coupled with electrospray ionisation quadrupole-time of flight mass spectrometry. Analyses profiles were subjected to principal components analysis and orthogonal projection to latent structures discriminant analysis using the SIMCA-P software for biomarker selection and identification. Based on the MS/MS spectra and data from the literature, potential biomarkers, mainly of phosphatidylcholine and lysophosphatidylcholine, were identified. Identification of these biomarkers suggested that plasma membrane phospholipids underwent major changes during the life history of P.haitanensis. The levels of phosphatidylcholine and lysophosphatidylcholine increased in sporangial branchlets and decreased in discharged conchospores. Moreover, levels of sphingaine (d18:0) decreased in sporangial branchlets and increased in discharged conchospores, which indicates that membrane lipids were increasingly synthesised as energy storage in sporangial branchlets, while energy was consumed in sporangial branchlets to discharged conchospores. A metabolomic study of different growth phases of P.haitanensis will enhance our understanding of its physiology and ecology.

Identification and Efficient Utilization of Antibiotics for the Development of a Stable Transformation System in Porphyra yezoensis (Bangiales,Rhodophyta)

Despite the development of transient gene expression in red algae Porphyra species, a stable transformation system has not been stablished in these algae yet. One reason for the difficulty in the transformation is the lack of a way to select transformed cells from the algae. Thus, to identify antibiotics suitable for the selection of stably transformed cells, we tested the gametophyte for sensitivity to 6 antibiotics, ampicillin (Am), kanamycin (Km), hygromycin (Hm), geneticin (G418), chloramphenicol (Cm) and paromomycin (Pm), which are frequently employed as selection agents in the transformation of land plants and microalgae. Sensitivity tests, which were carried out with different concentrations (0-10 mg mL-1) of antibiotics, showed that Hm, G418, Cm and Pm exhibited a lethal effect at more than 1.0 mg mL-1, suggesting the suitability of these four antibiotics for the selection of genetically transformed cells from P. yezoensis gametophytes, while P. yezoensis gametophytes were highly resistant to Am and Km. We also succeeded in reducing the antibiotic concentrations by lowering the pH value and salt concentration using an artificial synthetic medium. Increasing the sensitivity of gametophytic cells to Hm, G418, Cm and Pm in the modified synthetic medium will contribute to establishing a genetic transformation system in P. yezoensis.

Massive difference in synonymous substitution rates among mitochondrial, plastid, and nuclear genes of Phaeocystis algae

We are just beginning to understand how mutation rates differ among mitochondrial, plastid, and nuclear genomes. In most seed plants the mitochondrial mutation rate is estimated to be lower than those of the plastid and nucleus, whereas in the red alga Porphyra the opposite is true, and in certain green algae all three genomes appear to have similar rates of mutation. Relative rate statistics of organelle vs nuclear genes, however, are lacking for lineages that acquired their plastids through secondary endosymbiosis, but recent organelle DNA analyses suggest that they may differ drastically from what is observed in lineages with primary plastids, such as green plants and red algae. Here, by measuring synonymous nucleotide substitutions, we approximate the relative mutation rates within the haptophyte genus Phaeocystis, which has a red-algal-derived, secondary plastid. Synonymous-site divergence data indicate that for Phaeocystis antarctica and P. globosa the mitochondrial mutation rate is 10 and 3 times that of the plastid and nucleus, respectively. This differs drastically from relative rate estimates for primary-plastid-bearing lineages and presents a much more dynamic view of organelle vs nuclear mutation rates across the eukaryotic domain.

Oxidative stress and antioxidant indices of the marine red alga Porphyra vietnamensis

Abstract -Oxidative stress and antioxidant defence systems were assessed in a marine red alga Porphyra vietnamensis Tanaka et Pham-Hoang Ho, from India. Lipid peroxidation (LPX) and hydrogen peroxide (H2O2) were measured as oxidative stress markers. Antioxidant defences were measured as catalase (CAT), glutathione S-transferase (GST) and ascorbic acid (AsA), in order to understand their dissimilarity with respect to environmental conditions (pollution levels) from selective locations along the central west coast of India. Levels of LPX, H2O2, CAT and GST were significantly higher in samples collected from Dona Paula than in samples from Malvan and Kunkeshwar, while a lower concentration of AsA was found in samples from Dona Paula. Heavy metals such as Cd, Pb and Hg in higher concentrations in these areas than in other sites were also observed. Variation of oxidative stress indices in response to the accumulation of heavy metals within P. vietnamensis could be used as molecular biomarkers for the assessment and monitoring of environmental quality in ecologically sensitive marine habitats.

Algimonas ampicilliniresistens sp. nov., isolated from the red alga Porphyra yezoensis, and emended description of the genus Algimonas

Three strains (14A-2-7(T), 14A-3-1 and 14A-3) of Gram-stain-negative, prosthecate, motile bacteria were isolated from an algal medium supplemented with 10 mg ampicillin l(-1) (w/v), in which the red alga Porphyra yezoensis had been cultured. Based on the 16S rRNA gene sequence analysis, the three isolates formed a cluster with the genus Algimonas of the family Hyphomonadaceae. The sequences of the three isolates had high similarity with those of Algimonas porphyrae 0C-2-2(T) (97.6 % similarity) and Litorimonas taeanensis G5(T) (95.6 % similarity). The DNA G+C contents of the three isolates ranged from 54.3 to 55.0 mol%, which were more similar to that of A. porphyrae 0C-2-2(T) (58.5 mol%) than to that of L. taeanensis G5(T) (47.1 mol%). The DNA-DNA relatedness showed that the three isolates were representatives of the same species (88.1-94.0 % relatedness) and that strain 14A-2-7(T) was a representative of a different species from A. porphyrae 0C-2-2(T) and L. taeanensis G5(T) (1.2-8.6 % relatedness). The phenotypic characteristics of strain 14A-2-7(T) differed by 20 results and 30 results from A. porphyrae 0C-2-2(T) and L. taeanensis G5(T), respectively. The three isolates contained ubiquinone-10 as the predominant quinone and C18 : 1ω7c as the major fatty acid. Based on the polyphasic taxonomic analysis, the three isolates represent a novel species of the genus Algimonas, for which the name Algimonas ampicilliniresistens sp. nov. is proposed. The type strain is 14A-2-7(T) ( = LMG 26421(T) = NBRC 108219(T)). An emended description of the genus Algimonas is also proposed.

Variation of Expression Levels of Seven Housekeeping Genes at Different Life-History Stages in Porphyra yezoensis

In order to identify the optimal internal control for relative real-time PCR when studying target gene expression in the red alga Porphyra yezoensis, we quantified the expression of seven housekeeping genes (18S ribosomal RNA, 30S ribosomal protein S8, Polyubiquitin-2, Glyceraldehyde-3-phosphate dehydrogenase, Elongation factor 1-alpha, Beta-tubulin and Actin 3) at different life-history stages. Absolute quantification was done by normalization to total RNA quantity and by normalization to genomic DNA quantity. We used these two normalization approaches, comparing the differences of expression levels of all candidate housekeeping genes between any two generations and across three life-history stages (filamentous sporophytes, leafy gametophytes and conchospores). We found GAPDH had the best stability in all cases and we recommend that GAPDH be considered as a potential internal control for gene expression studies at different life-history stages in P. yezoensis.

Chemical composition and moisture-absorption/retention ability of polysaccharides extracted from five algae

In this study, we prepared seven polysaccharides extracted from five algae including one brown alga Saccharina japonica, one red alga Porphyra haitanensis and three green algae Codium fragile, Enteromorpha linza and Bryopsis plumose. The chemical composition and capability of moisture-absorption and moisture-retention were investigated in comparison with those of hyaluronic acid (HA). The low molecular weight polysaccharides extracted from brown seaweed exhibited the highest moisture-absorption and moisture-retention abilities of all of the polysaccharides studied and performed better than HA. The relationships between chemical composition (including sulfated groups, monosaccharide, and molecular weight) and the functions of polysaccharides were also studied. We found the sulfated group was a main active site for moisture-absorption and moisture-retention abilities. These abilities were also related to molecular weight; with the exception of the low molecular weight polysaccharide extracted from red seaweed, lower molecular weight improved moisture-absorption and moisture-retention abilities.