Ira A. Levine

Analysis of Porphyra Membrane Transporters Demonstrates Gene Transfer among Photosynthetic Eukaryotes and Numerous Sodium-Coupled Transport Systems

Membrane transporters play a central role in many cellular processes that rely on the movement of ions and organic molecules between the environment and the cell, and between cellular compartments. Transporters have been well characterized in plants and green algae, but little is known about transporters or their evolutionary histories in the red algae. Here we examined 482 expressed sequence tag contigs that encode putative membrane transporters in the economically important red seaweed Porphyra (Bangiophyceae, Rhodophyta). These contigs are part of a comprehensive transcriptome dataset from Porphyra umbilicalis and Porphyra purpurea. Using phylogenomics, we identified 30 trees that support the expected monophyly of red and green algae/plants (i.e. the Plantae hypothesis) and 19 expressed sequence tag contigs that show evidence of endosymbiotic/horizontal gene transfer involving stramenopiles. The majority (77%) of analyzed contigs encode transporters with unresolved phylogenies, demonstrating the difficulty in resolving the evolutionary history of genes. We observed molecular features of many sodium-coupled transport systems in marine algae, and the potential for coregulation of Porphyra transporter genes that are associated with fatty acid biosynthesis and intracellular lipid trafficking. Although both the tissue-specific and subcellular locations of the encoded proteins require further investigation, our study provides red algal gene candidates associated with transport functions and novel insights into the biology and evolution of these transporters.

Porphyra: Complex Life Histories in a Harsh Environment: P. umbilicalis, an Intertidal Red Alga for Genomic Analysis

Porphyra encompasses a large group of multicellular red algae that have a prominent gametophytic phase. The complex, heteromorphic life history of species in this genus, their remarkable resilience to high light and desiccation, ancient fossil records, and value as human food (e.g., laver, nori), make Porphyra a compelling model for genome sequencing. Sequencing of the nuclear genome of Porphyra umbilicalis from the northwestern Atlantic is currently in process. The ∼270 Mb genome of this alga is much larger than that of the unicellular acidophilic Cyanidioschyzon merolae (16.5 Mb), the only rhodophyte for which there is a fully sequenced genome, and is approximately twice as large as the Arabidopsis genome. Future analyses of the P. umbilicalis genome should provide opportunities for researchers to (1) develop an increased understanding of the ways in which these algae have adapted to severe physiological stresses, (2) elucidate the molecular features of development through the complex life history, and (3) define key components required for the transition of growth from a single cell to a multicellular organism.

Molecular features of a defined genetic marker for the determination of the Porphyra tenera lineage.

Nucleotide sequences of the nuclear SSU rDNA and ITS1 are presented as a defined genetic marker for Porphyra tenera as a species. Exon nucleotide sequences were identical within all the P. tenera specimens. Intron nucleotide sequences varied between populations. The introns and ITS1 variations are presented as defined genetic markers to establish the Porphyra tenera strains. Wild-collected thalli identified by morphological systematics, from five populations of Porphyra tenera throughout Japan, were discriminated by comparing sequences of the various regions utilizing the results of this and previous studies.

Biology of Seaweeds

Abstract Seaweeds or macroalgae are generally grouped into three taxa: green, brown, and red algae. (A more comprehensive review of seaweed systematics can be found in chapter: Macroalgae Systematics .) They are important bioresources of the oceans and play a major role in the maintenance of its ecosystem. These marine algae are utilized for food, fodder, polysaccharide extraction, biofertilizers, cosmetics, papermaking, and biobased fuels. In this chapter, numerous topics on seaweed biology are covered including: the role in maintenance of ocean ecology, herbivory and predation defense mechanisms, life history of important seaweeds, and their commercial applications.

Algae as a Source of Biofuel

Discovering the next source of transportation fuels remains one of the greatest challenges in the twenty-first century for governments and scientists. Bio-based fuels, currently the source of less than 1 % of the transportation fuel supply chain, represent a potential renewable feedstock. Presently, arable land-based biofuel feedstock production has resulted in an increase in food values and environmental degradation. Contrasting traditional agrarian-based feedstocks, algae represent a carbon neutral alternative. The resurgence in micro and macroalgal-based biofuels has resulted in numerous studies on the production of biodiesel, bioethanol, and biogas. The fundamental economic modeling of algal-based biofuels does not support the direct utilization of algae as a feedstock as the various algal bioproducts are far more valuable. As a result, algal-based biofuel production will be economically viable when fully integrated into complete bioproducts/biofuel processing strategy which will be covered in this paper.

Antiallergic and Allergic Properties

Abstract Some microalgae or cyanobacteria have been described as new candidates for the development of antiallergic agents. Microalgae belonging to the species Porphyridium cruentum or Dunaliella salina can inhibit the hyaluronidase enzyme, which is known to be involved in the inflammatory reactions. In the same context, Chlorella sp. extracts seem to possess a beneficial role against allergic inflammation. Regarding cyanobacteria, a major inhibitory role in allergic reactions has been reported for Arthrospira sp. by mitigating anaphylactic shock and decreasing of histamine release. The substances involved in these anti-inflammatory or antiallergic properties are mainly polysaccharides, peptides, pigments, or lipids such as sulfolipids. Paradoxically, microalgae or cyanobacteria can be also described for their allergic activities. Sometimes, they are the same species (Chlorella, Arthrospira) that were described for their antiallergic activities. However, the environmental context seems to be the main cause of this apparent paradox. This chapter is an overview of species or compounds extracted from microalgae or cyanobacteria possessing a role in the inhibition of inflammatory phenomenon. It also includes a description of the special forms or conditions for which the microalgae or cyanobacteria produce allergic reactions.

The Algae Foundation® and algal-based education initiatives

The Algae Foundation®, an American non-profit organization formed in February 2013, is developing a rich portfolio of algal-based Science, Technology, Engineering and Math (STEM) initiatives. The Algae Foundation’s efforts include the following: (1) formation of the Algae Technology Educational Consortium (ATEC); (2) development of two community college degrees: (i) Algal Biology and Cultivation and (ii) Algal Biotechnology; (3) development of the Algae Cultivation Extension Short-courses (ACES); (4) kindergarten to 12th grade (K–12) algal-based STEM curriculum initiatives; (5) student scholarships; and (6) funding of the revision of the Industrial Algae Measurements publication. The Algae Foundation® has been supported by more than 50 volunteers dedicating their time and intellectual capital to achieving its stated goals. The ATEC effort has initiated its first degree program in Algal Biology and Cultivation at Santa Fe Community College (SFCC), New Mexico, USA, in the Fall 2016 semester. The Algal Biotechnology degree program is scheduled to start in the Fall 2017 semester at Austin Community College (ACC), Texas, USA. A K–12 algal-based STEM initiative completed its pilot debut at the Aviara Oaks Middle School, Carlsbad, California, USA, in Spring 2016. The expansion of the algal curriculum K–12 program will reach 50 schools in 2017 to be followed by a national rollout in 2018.