Trait‐based analysis of subpolar North Atlantic phytoplankton and plastidic ciliate communities using automated flow cytometer

Plankton are an extremely diverse and polyphyletic group, exhibiting a large range in morphological and physiological traits. Here, we apply automated optical techniques, provided by the pulse‐shape recording automated flow cytometer—CytoSense—to investigate trait variability of phytoplankton and plastidic ciliates in Arctic and Atlantic waters of the subpolar North Atlantic. We used the bio‐optical descriptors derived from the CytoSense (light scattering [forward and sideward] and fluorescence [red, yellow/green and orange from chlorophyll a, degraded pigments, and phycobiliproteins, respectively]) and translated them into functional traits to demonstrate ecological trait variability along an environmental gradient. Cell size was the master trait varying in this study, with large photosynthetic microplankton (> 20 μm in cell diameter), including diatoms as single cells and chains, as well as plastidic ciliates found in Arctic waters, while small‐sized phytoplankton groups, such as the picoeukaryotes (< 4 μm) and the cyanobacteria Synechococcus were dominant in Atlantic waters. Morphological traits, such as chain/colony formation and structural complexity (i.e., cellular processes, setae, and internal vacuoles), appear to favor buoyancy in highly illuminated and stratified Arctic waters. In Atlantic waters, small cell size and spherical cell shape, in addition to photo‐physiological traits, such as high internal pigmentation, offer chromatic adaptation for survival in the low nutrient and dynamic mixing waters of the Atlantic Ocean. The use of automated techniques that quantify ecological traits holds exciting new opportunities to unravel linkages between the structure and function of plankton communities and marine ecosystems

The anti-NgR1 antibody, 1D9, rescues rat retinal ganglion cells after optic nerve transection and ocular hypertension-induced glaucoma

The neuronal leucine rich repeat protein, Nogo66 receptor [NgR1], interacts with at least three CNS myelin proteins [Nogo, MAG and OMgp] and mediates the inhibition of neurite growth. Here we report a monoclonal anti-NgR1 antibody, 1D9, that in addition to inhibiting these interactions in vitro, exhibits neuroprotective properties in vitro and in vivo. Structural analyses performed on the co-crystal complex of the 1D9 Fab and a soluble fragment of NgR1 (sNgR310) indicate that this antibody binds near the junction of the N-terminus cap and leucine rich repeat domain on NgR1. Treatment with 1D9 protected primary neuronal cultures from insults derived from serum withdrawal. Direct intravitreal administration of 1D9 Fab, but not the full 1D9 mAb, consistently promoted the survival of retinal ganglion cells in an optic nerve transection model and an ocular hypertension induced glaucoma model in rat. The lack of activity of the full 1D9 mAb may be partially attributed to NgR1 activation via receptor cross-linking as demonstrated by rhoA activation assay. These results suggest that 1D9 Fab may confer neuroprotection to specific subsets of neurons. Equal contribution: B Hu, A Jirik, and Q Fu Corresponding authors: KF So and DHS Le

Harvesting of Microalgae for Biomass Production

Microalgae have a great commercial potential as a source of several compounds of interest to the food, pharmaceutical, and chemical industries. The market was estimated to be around US$1.25 billion per year with more than 20 different commercial products and the genera commercially produced are mainly Chlorella, Arthrospira (Spirulina), Dunaliella, and Haematococcus, with a produc- tion of 5.000 tons of dry matter in 2004, increasing to 9.000 tons in 2010. However, despite extensive research carried out to date, harvesting is still one of the most costly processes in microalgae production. Consequently, the microalgae that are currently produced commercially are mainly indented for high value products (>$10,000 ton-1). The aim of this chapter is to give an overview of the major constraints and technologies available for harvesting microalgae