Health Benefits and Pharmacological Effects of Porphyra Species.

Porphyra, one of the most cultured red algae has gained economic importance across the globe for its nutritional benefits. Porphyra is being cultivated, harvested, dried, processed and consumed in large quantities in south eastern countries. It contains relatively high amounts of proteins, carbohydrates, and micronutrients. Exploitation of its fundamental attributes led to the discovery of various biologically active compounds like polysaccharides, phycobiliproteins and peptides with effective pharmacological applications. In this review, a systematic account of the research accomplished in the past decade and up-to-date overview of various bioactive compounds and its pharmacological implications has been compiled. This review summarizes the bioactivities like antioxidative, immunomodulatory, antihypertensive, anticoagulant and anticancer properties of the bioactive compounds from Porphyra.

Development and characterization of twelve microsatellite markers for Porphyra linearis Greville.

The genus Porphyra (and its sister genus Pyropia) contains important red algal species that are cultivated and/or harvested for human consumption, sustaining a billion-dollar aquaculture industry. A vast amount of research has been focused on species of this genus, including studies on genetics and genomics among other areas. Twelve novel microsatellite markers were developed here for Porphyra linearis. Markers were characterized using 32 individuals collected from four natural populations of P. linearis with total heterozygosity varying from 0.098 to 0.916. The number of alleles per locus ranged from 2 to 18. All markers showed cross amplification with Porphyra umbilicalis and/or Porphyra dioica. These polymorphic microsatellite markers are useful for investigating population genetic diversity and differentiation in P. linearis and may become useful for other genetic research on the reproductive biology of this important species.

Complete mitochondrial genome of Pyropia yezoensis: reasserting the revision of genus Porphyra.

Pyropia yezoensis Ueda, belonging to the Bangiales order Rhodophyte, is economically important seaweed distributed along the coastal region of the northwest Pacific. In this study, we report the complete mitochondrial DNA sequences of P. yezoensis. The entire genome comprised 41,688 bp with circular organization, which is the longest among the red algae sequenced to date. The overall AT composition is 62.22% and the average AT content of PCG, 16S rRNA, tRNA and noncoding region are 67.51%, 65.23%, 61.23% and 72.67%, respectively The mitochondrial DNA of P. yezoensis encoded 23 proteins, 4 open reading frames, 3 ribosomal RNAs and 27 transfer RNA genes. The comparison analyses showed that obvious variation occurred on the gene content and gene structure among P. yezoensis. P. haitanensis and Porphyra purpurea. Phylogenetic analysis revealed that P. yezoensis is more closely related to P. haitanensis than to P. purpurea, and P. purpurea was phylogenetically distinct from the two species, which confirmed the reassignment of Pyropia and Porphyra in Bangiaceae.

Metabolic phenotypes associated with high-temperature tolerance of Porphyra haitanensis strains.

Colored mutants of Porphyra haitanensis have superior production and quality characteristics, with two mutants, Shengfu 1 (SF-1) and Shengfu 2 (SF-2), having good high-temperature tolerances. To understand the molecular aspects of high-temperature tolerance, this study comprehensively investigated the metabolic differences between the high-temperature tolerant strains and wild type. Nuclear magnetic resonance (NMR) methods identified 35 algal metabolites, including sugars, amino acids, carboxylic acids, aldehydes, amines, and nucleotides. The results indicated that the high-temperature tolerant strains had significantly different metabolic phenotypes from the wild type. The high-temperature tolerant mutants had significantly higher levels in a set of osmolytes consisting of betaine, taurine, laminitol, and isofloridoside than the wild type, indicating the particular importance of efficient osmoregulation for high-temperature resistance. These findings provided essential metabolic information about high-temperature adaptation for P. haitanensis and demonstrated NMR-based metabolomics as a useful tool for understanding the metabolic features related to resistance to stressors.

Heat shock protein gene family of the Porphyra seriata and enhancement of heat stress tolerance by PsHSP70 in Chlamydomonas.

Heat shock proteins and molecular chaperones are key components contributing to survival in the abiotic stress response. Porphyra seriata grows on intertidal rocks exposed to dynamic environmental changes associated with the turning tides, including desiccation and heat stress. Analysis of the ESTs of P. seriata allows us to identify the nine HSP cDNAs, which are predicted to be PsHSP90, three PsHSP70, PsHSP40 and PsHSP20, and three 5'-truncated HSP cDNAs. RT-PCR results show that most of the PsHSP transcripts were detected under normal cell growth conditions as well as heat stress, with the exception of two cDNAs. In particular, PsHSP70b and PsHSP20 transcripts were upregulated by heat stress. When the putative mitochondrial PsHSP70b was introduced and overexpressed in Chlamydomonas, transformed Chlamydomonas evidenced higher rates of survival and growth than those of the wild type under heat stress conditions. Constitutive overexpression of the PsHSP70b gene increases the transcription of the HSF1 as well as the CrHSP20 and CrHSP70 gene. These results indicate that PsHSP70b is involved in tolerance to heat stress and the effects on transcription of the CrHSP20 and CrHSP70 genes.

Two different clades of copia-like retrotransposons in the red alga, Porphyra yezoensis.

A copia-like retrotransposon referred to as PyRE1G1 was isolated from the genome of the red alga Porphyra yezoensis. PyRE1G1 is 4807 bp in length, with 204 bp long terminal repeats (LTRs) at both ends. PyRE1G1 has an open reading frame of 1401 residues encoding gag, protease, integrase, reverse transcriptase (RT), and RNase H. From the order of gene arrangement of proteins, PyRE1G1 appears to be a copia-like retrotransposon. Genomic Southern blot analysis suggests that PyRE1G1 consists of a small gene family. From the phylogenetic tree of RT sequences, PyRE1G1 is grouped in the clade of usual copia elements and distinct from the previously isolated red algal copia-like gene PyRE10G in that the latter is closely related to a new clade of aquatic animal-specific copia-like retrotransposons.