Glaucophyta

Abstract: The endosymbiosis event resulting in the plastid of photosynthetic eukaryotes was accompanied by the appearance of a novel form of storage polysaccharide in Rhodophyceae, Glaucophyta, and Chloroplastida. Previous analyses indicated that starch synthesis resulted from the merging of the cyanobacterial and the eukaryotic storage polysaccharide metabolism pathways. We performed a comparative bioinformatic analysis of six algal genome sequences to investigate this merger. Specifically, we analyzed two Chlorophyceae, Chlamydomonas reinhardtii and Volvox carterii, and four Prasinophytae, two Ostreococcus strains and two Micromonas pusilla strains. Our analyses revealed a complex metabolic pathway whose intricacies and function seem conserved throughout the green lineage. Comparison of this pathway to that recently proposed for the Rhodophyceae suggests that the complexity that we observed is unique to the green lineage and was generated when the latter diverged from the red algae. This finding corresponds well with the plastidial location of starch metabolism in Chloroplastidae. In contrast, Rhodophyceae and Glaucophyta produce and store starch in the cytoplasm and have a lower complexity pathway. Cytoplasmic starch synthesis is currently hypothesized to represent the ancestral state of storage polysaccharide metabolism in Archaeplastida. The retargeting of components of the cytoplasmic pathway to plastids likely required a complex stepwise process involving several rounds of gene duplications. We propose that this relocation of glucan synthesis to the plastid facilitated evolution of chlorophyll-containing light-harvesting complex antennae by playing a protective role within the chloroplast.

Abstract: Phycocyanin is an important light-harvesting pigment antenna protein in cyanobacteria, rhodophyta, cryptophyta, and glaucophyta, with a variety of bioactivities The introduction of purification and bioactivities of phycocyanin contributes to a significant improvement in developing it into final processed products In fact, the knowledge of phycocyanin has experienced a rapid increase in the past 20 years, and has promoted the relevant technological revolution with a decisive contribution to final application The purpose of this review is to critically introduce the present knowledge of purification and bioactivities of phycocyanin, and to illustrate main problems and prospects

Abstract: Oxygenic photosynthesis, the chemical process whereby light energy powers the conversion of carbon dioxide into organic compounds and oxygen is released as a waste product, evolved in the anoxygenic ancestors of Cyanobacteria. Although there is still uncertainty about when precisely and how this came about, the gradual oxygenation of the Proterozoic oceans and atmosphere opened the path for aerobic organisms and ultimately eukaryotic cells to evolve. There is a general consensus that photosynthesis was acquired by eukaryotes through endosymbiosis, resulting in the enslavement of a cyanobacterium to become a plastid. Here, we give an update of the current understanding of the primary endosymbiotic event that gave rise to the Archaeplastida. In addition, we provide an overview of the diversity in the Rhodophyta, Glaucophyta and the Viridiplantae (excluding the Embryophyta) and highlight how genomic data are enabling us to understand the relationships and characteristics of algae emerging from this primary endosymbiotic event.