Proteomics and transcriptomics findings on lipids accumulation in Nannochloropsis
Confocal microscopy image of Nannochloropsis cell grown in nitrogen deprivation. Lipid droplets are in yellow and chloroplast is in red. From “Going ultra deep to unravel the secret recipe of biofuel” by Elisa Corteggiani Carpinelli
What is the mechanism by which Nannochloropsis cells synthesise and accumulate lipids in certain culturing conditions? And moreover is there a key control that we can manipulate to improve lipid yields and overcome the tradeoff between lipid production and growth? This is probably the “holy grail” of Nannochloropsis research. The general feeling is that we do not have an answer yet, but at least we have some clues to start our quest.
FTP area updated
We updated our FTP area, now including datasets from other Nannochloropsis species and strains and the list of families of orthologous proteins obtained from the comparison of N. gaditana and N. oceeanica predicted proteins.
Families of orthologous proteins: file type
N.gaditanaB-31|Naga_100019g47.1 N.gaditanaCCMP526|Nga20827 nudix hydrolase;
Even though the differences and the imprecisions of the various gene predictions probably play a major role in the determination of the differences among the two species, a close look at the lists of proteins that are putatively assigned as characteristic of each species my reserve interesting surprises!
References
- Corteggiani Carpinelli, E. et al. “Chromosome scale genome assembly and transcriptome profiling of Nannochloropsis gaditana in nitrogen depletion.” Molecular Plant (2014) 7 (2): 323-335.doi: 10.1093/mp/sst120
We’re looking for new authors and contributors
Are you an expert about Nannochloropsis? Is your research focused on this organism?
Consider becoming a new author of this blog and contributing to the scientific discussion!
Why don’t you start with advertising your recent publication or commenting on the posts of this blog?
Is there any hot topic that you would like to discuss or any suggestion that you would like to ask to this scientific community?
Fill this form and we will be happy to consider you application as new author
Proteomics and transcriptomics findings on Nitrogen stress respons in Nannochloropsis
Nannochloropsis cultivated in normal growth condition and deprived of a nitrogen source continues growing for at least 4–5 days.
Analyses of the gene expression and of the protein abundance in nitrogen scarcity, reveal that Nannochloropsis activates mechanisms for nitrogen assimilation and redistribution to allow survival through a partial reorganisation of the cellular metabolism.
This figure reports the model of the response to nitrogen deprivation elaborated by Corteggiani Carpinelli et al. (2013).
DEGRADATIVE PROCESSES
Various genes involved in controlled degradation of proteins are over-expressed in the cells grown in nitrogen deprivation, including: cullin (Naga_100070g1), which is responsible for protein ubiquitination; ubiquitin-specific protease (Naga_100587g2); proteases (Naga_100611g3, Naga_100098g23, Naga_100015g80.1); endopeptidase Naga_101780g1); aminopeptidase (Naga_100024g51) and two autophagy-related proteins (Naga_101823g1 and Naga_100732g4), which are likely involved in the formation of cytosolic sequestering vesicles used for degradation and recycling of cellular components.
The proteomic study shows that the relative abundance of one subunit of the protein degrading complex (Proteasome subunit alpha) increases in nitrogen starvation supporting the evidence that processes of protein degradation are activated in response to nitrogen starvation. The analysis of protein abundance also suggests that in nitrogen starvation autophagy is induced. Indeed the abundance of a receptor-mediated endocytosis protein slightly increases and also that of two vacuolar proton pump subunits. These data, together with morfological observations, support the hypothesis that upon nitrogen deprivation the organelles are degraded in the vacuoles through a process of controlled autophagy.
Recent Comments