This paper describes the characteristics of microalgal strains that originated out of an 31 isolation and screening project included within the National Alliance for Advanced 32 Biofuels and Bioproducts (NAABB). The project's goal was to identify new potential 33 platform strains with high growth rates and/or lipid productivities. To classify the best 34 performing strains, we conducted a combined microscopic and phylogenetic analysis. 35Among the best performing strains were many coccoid green algae. Several strains 36 belong to the species Acutodesmus (Scenedesmus) obliquus and to the species Chlorella 37 sorokiniana, thus expanding on existing germplasm. Identified at the genus level were 38 some Desmodesmus strains and one Ankistrodesmus strain. Several strains were classified 39 as belonging to the genus Coelastrella, a taxon reported for the first time for North 40 America. Multiple additional strains had ambiguous identities, with some strains possibly 41 representing novel species. Reporting on the above strains, some of which have been 42tested successfully in outdoor ponds and most of which are deposited at the University of 43 Texas Culture Collection of Algae, is a step forward in expanding the biological 44 resources available for algae biofuel production.

Candida albicans adhesins have amyloid-forming sequences. In Als5p, these amyloid sequences cluster cell surface adhesins to create high avidity surface adhesion nanodomains. Such nanodomains form after force is applied to the cell surface by atomic force microscopy or laminar flow. Here we report centrifuging and resuspending S. cerevisiae cells expressing Als5p led to 1.7-fold increase in initial rate of adhesion to ligand coated beads. Furthermore, mechanical stress from vortex-mixing of Als5p cells or C. albicans cells also induced additional formation of amyloid nanodomains and consequent activation of adhesion. Vortex-mixing for 60 seconds increased the initial rate of adhesion 1.6-fold. The effects of vortex-mixing were replicated in heat-killed cells as well. Activation was accompanied by increases in thioflavin T cell surface fluorescence measured by flow cytometry or by confocal microscopy. There was no adhesion activation in cells expressing amyloid-impaired Als5pV326N or in cells incubated with inhibitory concentrations of anti-amyloid dyes. Together these results demonstrated the activation of cell surface amyloid nanodomains in yeast expressing Als adhesins, and further delineate the forces that can activate adhesion in vivo. Consequently there is quantitative support for the hypothesis that amyloid forming adhesins act as both force sensors and effectors.

The exact mechanisms underlying the distribution of fixed carbon within photoautotrophic cells, also referred to as carbon partitioning, and the subcellular localization of many enzymes involved in carbon metabolism are still unknown. In contrast to the majority of investigated green algae, higher plants have multiple isoforms of the glycolytic enolase enzyme, which are differentially regulated in higher plants. Here we report on the number of gene copies coding for the enolase in several genomes of species spanning the major classes of green algae. Our genomic analysis of several green algae revealed the presence of only one gene coding for a glycolytic enolase [EC 4.2.1.11]. Our predicted cytosolic localization would require export of organic carbon from the plastid to provide substrate for the enolase and subsequent re-import of organic carbon back into the plastids. Further, our comparative sequence study of the enolase and its 3D-structure prediction may suggest that the N-terminal extension found in green algal enolases could be involved in regulation of the enolase activity. In summary, we propose that the enolase represents one of the crucial regulatory bottlenecks in carbon partitioning in green algae.