Nannochloropsis’ whole cells were recently analysed using 13C-SS-NMR spectroscopy (reference n 1). Cells were grown autotrophically in a sodium [13C] bicarbonate environment and harvested during the exponential phase.
Quantitative spectra of 13C labelled cells of Nannochloropsis oculata were analysed for resonance picks which are characteristic of carbohydrates and lipids, thus providing, among other interesting observations, useful insights on the cell wall composition of the microalga.
We have already discussed in a previous post two possible models of cellular metabolism that can account for oil accumulation and that are in agreement with the profile of transcript and protein abundance in Nannochloropsis‘ cultures that accumulate lipids. New experimental data became recently available for the scientific community concerning this issue. Jing Li and coworkers performed a time course experiment, tracking simultaneously transcript abundance and lipid content of Nannochloropsis cultures grown in N sufficient (+N) and N depleted (-N) media. The data and their analysis were published on Plant Cell (doi: http://dx.doi.org/10.1105/tpc.113.121418). Full reference is reported at the end of this post (reference n 1).
Thanks to the sequencing of the genomes of two strains of Nannochloropsis gaditana  and two strains of Nannochloropsis oceanica  we now have the reference sequences to design molecular biology experiments on this microorganism. Moreover we have learnt a great deal of information, opened up new interrogatives .. and more will come analysing the data available though this portal and through the other web resources: N. gaditana CCMP526 genome and N. oceanica CCMP1779 genome.
Nannochloropsis genome is small, about 28-29 Mega bases, and very compact: there is on average 1 gene each 2.7 kilo bases in N. gaditana B-31, the genes are long on average 1.2 kilo bases and they contain very few introns.
The proteins predicted in the two species are in large part similar, about 80% of the proteins of each species are found in clusters of homologous proteins, ~60% of which accomodate proteins common to the two species. Further studies will help ruling out the limits and the inaccuracies of the gene predictions allowing to focus on the actual differences between the two species.
The pathways leading to the synthesis of cellulose and sulfated fucans and to the remodelling of cellulose in the cell wall have been identified both in N. gaditana and in N. oceanica, casting a light on the molecular composition of the cell wall and suggesting possible targets of genetic modification.