Project description:Background: Salinity is an important abiotic stress that influences the physiological and metabolic activity, reproduction, growth and development of marine fish. It has been suggested that half-smooth tongue sole (Cynoglossus semilaevis), a euryhaline fish species, use a large amount of energy to maintain osmotic pressure balance when exposed to fluctuations in salinity. To delineate the molecular response of C. semilaevis to different levels of salinity, we performed RNA-seq analysis of the liver to identify the genes and molecular and biological processes involved in responding to salinity change. Results: The present study yielded 330.4 million clean reads, of which 83.9% were successfully mapped to the reference genome of C. semilaevis. One hundred twenty-eight differentially expressed genes (DEGs), including 43 up-regulated genes and 85 down-regulated genes, were identified. These DEGs were highly represented in metabolic pathways, steroid biosynthesis, terpenoid backbone biosynthesis, butanoate metabolism, glycerolipid metabolism and the 2-oxocarboxylic acid metabolism pathway. In addition, genes involved in metabolism, osmoregulation and ion transport, signal transduction, immune response and stress response, cytoskeleton remodeling, and apoptosis were affected during acclimation to low salinity. Genes acat2, fdps, hmgcr, hmgcs1, mvk, pmvk, ebp, lss, dhcr7, and dhcr24 were up-regulated and abat, ddc, acy1 were down-regulated in metabolic pathways. Genes aqp10 and slc6a6 were down-regulated in osmoregulation and ion transport. Genes abat, fdps, hmgcs1, mvk, pmvk and dhcr7 were first reported to be associated with salinity adaptation in teleosts. Conclusions: Our results revealed that metabolic pathways, especially lipid metabolism were important for salinity adaptation. The candidate genes identified from this study provide a basis for further studies to investigate the molecular mechanism of salinity adaptation and transcriptional plasticity in marine fish.
Project description:Prochlorococcus is an obligate marine microorganism which are dominant autotroph in tropical and subtropical central oceans. However, what is the low salinity boundary and how Prochlorococcus would response to low salinity exposure is still unknown. In this study, we first tested the growing salinity range of two Prochlorococcus strains, NATL1A and MED4, and then compared the global transcriptome of their low salinity acclimated cells and cells growing in normal seawater salinity. We found that MED4 could be acclimated in the lowest salinity of 25% and NATL1A could be acclimated in the lowest salinity of 28%. Measurement of the effective quantum yield of PSII photochemistry (Fv/Fm) indicated that both strains were stressed when growing in salinity lower than 34%. The transcriptomic response of NATL1A and MED4 were approximately different, with much more genes having changed transcript abundance in NATL1A than in MED4. To cope with low salinity, NATL1A downregulated the transcript of most genes involved in translation, ribosomal structure and biogenesis, while MED4 upregulated those genes. Moreover, low salinity acclimated NATL1A cells suppressed ATP-producing genes and induced the expression of photosynthesis related genes, while low salinity acclimated MED4 upregulated ATP-producing genes and downregulated photosynthesis related genes. These results indicate that the response to low salinity stress of different Prochlorococcus strains could be distinct. The study provided the first glimpse into the growing salinity range of Prochlorococcus cells and their global gene expression changes due to low salinity stress.
Project description:Model legume Lotus japonicus was subjected to non-lethal long-term salinity and profiled at the transcriptomic level. Three independent experiments were performed, testing two experimental designs: a traditional gradual acclimation following a step-wise increase of salt concentration and an initial acclimation approach (ia).
Project description:Anaerobic microbial communities play a critical role in biogeochemical cycles through complex networks of interactions that influence community structure, stability, and functionality. This study investigates the metabolic interactions within synthetic communities composed of a cellulolytic bacterium (Ruminiclostridium cellulolyticum), a hydrogenotrophic methanogen (Methanospirillum hungatei), an acetoclastic methanogen (Methanosaeta concilii), and a sulfate-reducing bacterium (Desulfovibrio vulgaris). Through proteogenomic analysis and metabolic modeling, we quantified the metabolic interaction potential and metabolic resource overlap across bi-, tri-, and quad-cultures.