Development and characterization of twelve microsatellite markers for Porphyra linearis Greville

Immunomodulatory and Antitumoral Activity of Gold Nanoparticles Synthesized by Red Algae Aqueous Extracts

This study reports on the green and cost-efficient synthesis of gold nanoparticles from three different red algae extracts. The nanoparticles synthesized were fully characterized by UV-Vis spectroscopy, HRTEM, and Z-potential. Relevant components occurring in the extracts, such as polysaccharides or phenolic content, were assessed by analytical techniques such as spectrophotometric assays and liquid chromatography. Finally, the antioxidant, antitumoral, and anti-inflammatory potential of both the extracts and the gold nanoparticles synthesized were analyzed in order to determine a possible synergistic effect on the nanoparticles. The results obtained confirmed the obtainment of gold nanoparticles with significant potential as immunotherapeutic agents. The therapeutic potential of these nanoparticles could be higher than that of inert gold nanoparticles loaded with bioactive molecules since the former would allow for higher accumulation into the targeted tissue.

Biogeographic Population Structure of Chimeric Blades of Porphyra in the Northeast Atlantic Reveals Southern Rich Gene Pools, Introgression and Cryptic Plasticity

The genus Porphyra sensu lato (Bangiaceae, Rhodophyta), an important seaweed grown in aquaculture, is the most genetically diverse group of the Class Bangiophyceae, but has poorly understood genetic variability linked to complex evolutionary processes. Genetic studies in the last decades have largely focused on resolving gene phylogenies; however, there is little information on historical population biogeography, structure and gene flow in the Bangiaceae, probably due to their cryptic nature, chimerism and polyploidy, which render analyses challenging. This study aims to understand biogeographic population structure in the two abundant Porphyra species in the Northeast Atlantic: Porphyra dioica (a dioecious annual) and Porphyra linearis (protandrous hermaphroditic winter annual), occupying distinct niches (seasonality and position on the shore). Here, we present a large-scale biogeographic genetic analysis across their distribution in the Northeast Atlantic, using 10 microsatellites and cpDNA as genetic markers and integrating chimerism and polyploidy, including simulations considering alleles derived from different ploidy levels and/or from different genotypes within the chimeric blade. For P. linearis, both markers revealed strong genetic differentiation of north-central eastern Atlantic populations (from Iceland to the Basque region of Northeast Iberia) vs. southern populations (Galicia in Northwest Iberia, and Portugal), with higher genetic diversity in the south vs. a northern homogenous low diversity. For. P. dioica, microsatellite analyses also revealed two genetic regions, but with weaker differentiation, and cpDNA revealed little structure with all the haplotypes mixed across its distribution. The southern cluster in P. linearis also included introgressed individuals with cpDNA from P. dioica and a winter form of P. dioica occurred spatially intermixed with P. linearis. This third entity had a similar morphology and seasonality as P. linearis but genomes (either nuclear or chloroplast) from P. dioica. We hypothesize a northward colonization from southern Europe (where the ancestral populations reside and host most of the gene pool of these species). In P. linearis recently established populations colonized the north resulting in homogeneous low diversity, whereas for P. dioica the signature of this colonization is not as obvious due to hypothetical higher gene flow among populations, possibly linked to its reproductive biology and annual life history.

Gamma-irradiation degraded sulfated polysaccharide from a new red algal strain Pyropia yezoensis Sookwawon 104 with in vitro antiproliferative activity

Pyropia yezoensis Sookwawon 104 is a newly cultivated strain of red marine algae. The present study aimed to investigate the in vitro antiproliferative activity of sulfated polysaccharide extracted from P. yezoensis Sookwawon 104 (PYSP), as well as that of its low molecular weight (Mw) derivatives. PYSP is a heterogeneous sulfated polysaccharide mainly composed of galactose, glucose and fucose. PYSP was degraded by gamma-irradiation at doses of 20 and 100 kGy to produce two derivatives, named as PYSP-20 and PYSP-100, respectively. Comparison of PYSP, PYSP-20 and PYSP-100 revealed clear differences in their molecular weight (Mw) distributions, and distinct in vitro antiproliferative activities against Hep3B, MDA-MB-231 and HeLa cancer cell lines. PYSP-20 and PYSP-100 exhibited stronger antiproliferative effects than PYSP, suggesting that the reduction in Mw may have increased the in vitro antiproliferative activity. Furthermore, the mRNA expression levels of the antitumor gene P53 and cell cycle-associated genes P21, Cyclin B1 and cyclin dependent kinase 1 (Cdk1) were further analyzed by reverse transcription-quantitative PCR in PYSP-20 and PYSP-100-treated cancer cells. PYSP and its derivatives were shown to inhibit the proliferation of tumor cells by regulating the expression of P53, P21, Cyclin B1 and Cdk1. In conclusion, low-Mw polysaccharide derivatives prepared from P. yezoensis Sookwawon 104 by gamma-irradiation exhibit significant inhibition effects on cancer cell proliferation in vitro and may be a novel source of potential anticancer therapeutic agents.

Polyploid lineages in the genus Porphyra

Whole genome duplication is now accepted as an important evolutionary force, but the genetic factors and the life history implications affecting the existence and abundance of polyploid lineages within species are still poorly known. Polyploidy has been mainly studied in plant model species in which the sporophyte is the dominant phase in their life history. In this study, we address such questions in a novel system (Porphyra, red algae) where the gametophyte is the dominant phase in the life history. Three Porphyra species (P. dioica, P. umbilicalis, and P. linearis) were used in comparisons of ploidy levels, genome sizes and genetic differentiation using flow cytometry and 11 microsatellite markers among putative polyploid lineages. Multiple ploidy levels and genome sizes were found in Porphyra species, representing different cell lines and comprising several cytotype combinations among the same and different individuals. In P. linearis, genetic differentiation was found among three polyploid lineages: triploid, tetraploid and mixoploids, representing different evolutionary units. We conclude that the gametophytic phase (n) in Porphyra species is not haploid, contradicting previous theories. New hypotheses for the life histories of Porphyra species are discussed.