Project description:In fungal species, differentiation to the filamentous/hyphal cell type is critical for entry into host cells and virulence. Comparative RNA sequencing was used to explore the pathways that regulate differentiation to the filamentous cell type in yeast. This approach uncovered a role for the stress-response MAPK pathway, HOG, during the increased metabolic respiration that induces filamentous growth. In this context, the AMPK Snf1p and ER stress kinase Ire1p regulated the HOG pathway. Cross-modulation between the HOG and filamentous growth (ERK-type) MAPK pathways optimized the differentiation response. The regulatory circuit described here may extend to behaviors in metazoans. Comparison of expression patterns of wild-type and mutant yeast cells grown in salt, tunicamycin or galactose by comparative RNA sequencing analysis.
Project description:Transcriptome profiling of whole proboscis and body wall of the marine Polychaeta Glycera alba, adults, wild population (sex undiscriminated), collected from the muddy-sandy intertidal flats at W Portugal (2020). Transcriptome profiling of glandular and muscular regions of proboscis of the marine Polychaeta Hediste diversicolor, adults, wild population (sex undiscriminated), collected from the muddy-sandy intertidal flats at W Portugal (2019).
Project description:Cyanobacteria are phototrophic prokaryotes that can convert inorganic carbon as CO2 into organic carbon compounds at the expense of light energy. In addition, they need only a few inorganic nutrients and can be cultivated in high densities using non-arable land and seawater. This features qualified cyanobacteria as attractive organisms for the production of third generation biofuels as part of the development of future CO2-neutral energy production. Synechocystis sp. PCC 6803 represents one of the most widely used cyanobacterial model strains. On the basis of its available genome sequence and genetic tools, many strains of Synechocystis have been generated that produce different biotechnological products. Efficient isoprene production is an attractive goal, since this compound represents not only an energy-rich biofuel but is also used as chemical feedstock. Here, we report on our attempts to generate isoprene-producing strains of Synechocystis. The cDNA of a codon-optimized plant isoprene synthase (IspS) was cloned under the control of different Synechocystis promoters, which ensure strong constitutive or light-regulated ispS expression. The expression of the ispS gene was quantified by qPCR, whereas the amount of isoprene was quantified using GC-MS. Incubation of our strains at different salt conditions had marked impact on the isoprene production rates. Under low salt conditions, a good correlation was found between ispS expression and isoprene production rate. However, the cultivation of isoprene production strains under salt-supplemented conditions decreased isoprene production despite the fact that ispS expression was salt-stimulated. The characterization of the metabolome of isoprene producing strains indicated that isoprene production might be limited by insufficient precursor levels. Our isoprene production rates under low salt conditions were 2 - 6.5times higher compared to the previous report of Lindberg et al. (2010). These results can be used to guide future attempts establishing the isoprene production with cyanobacterial host systems.
2015-11-13 | GSE74940 | GEO
Project description:Nine biofilm-forming filamentous strains of Cyanobacteria from mangroves of Guadeloupe
Project description:Adaptation to changes in the environment is crucial for the viability of all organisms. Although the importance of calcineurin in the stress response has been highlighted in filamentous fungi, little is known about the involvement of ion-responsive genes and pathways in conferring salt tolerance without calcium signaling. In this study, high-throughput RNA-seq was used to investigate salt stress-induced genes in the parent, ΔcnaB, and ΔcnaBΔcchA strains of Aspergillus nidulans, which differ greatly in their salt adaption under salt stress. In total, 2,884 differentially expressed genes including 1,382 up- and 1,502 down-regulated genes were identified. Secondary transporters, which were up-regulated to a greater extent in ΔcnaBΔcchA than in the parent or ΔcnaB strains, are likely to play important roles in response to salt stress. Furthermore, 36 genes were exclusively up-regulated in the ΔcnaBΔcchA mutant under salt stress. Functional analysis of differentially expressed genes revealed that genes involved in transport, heat shock protein binding, and cell division processes were exclusively activated in ΔcnaBΔcchA. Overall, our findings reveal that secondary transporters and stress-responsive genes may play crucial roles in salt tolerance to bypass the requirement for the CchA-calcineurin pathway, contributing to a deeper understanding of the mechanisms that influence fungal salt stress adaption in Aspergillus.
Project description:In eubacteria, replacement of one σ factor in the RNA polymerase (RNAP) holoenzyme by another one changes the transcription pattern. Cyanobacteria are eubacteria characterized by oxygenic photosynthesis and they typically encode numerous group 2 σ factors that closely resemble the essential primary σ factor. A mutant strain of the model cyanobacterium Synechocystis sp. PCC 6803 without functional group 2 σ factors (named as ΔsigBCDE) could not acclimate to heat, high salt, or bright light stress but in standard conditions ΔsigBCDE grew only 9% slower than the control strain. One-fifth of the genes in ΔsigBCDE were differently expressed compared to the control strain in standard growth conditions and several physiological changes in photosynthesis, and pigment and lipid compositions were detected. To directly analyze the σ factor content of RNAP holoenzyme in vivo, a His-tag was added to the γ subunit of RNAP in Synechocystis and RNAPs were collected. The results revealed that all group 2 σ factors were recruited by RNAP in standard conditions, but recruitment of SigB and SigC increased in heat stress, SigD in bright light, SigE in darkness and SigB, SigC and SigE in high salt, explaining the poor acclimation of ΔsigBCDE to these stress conditions. Cells from cyanobacteria Synechocystis sp. PCC 6803 named as control strain (CS) and a mutant strain without any functional group 2 sigma factors, ΔsigBCDE, were harvested (A730=1, 40 mL) directly from standard growth conditions (continuous illumination at the PPFD of 40 µmol m-2s-1, 32°C, ambient CO2). From three to four independent experiments were performed at each conditions.