Project description:Pseudomonas extremaustralis an Antarctic bacterium was grown at low oxygen conditions and exposed to oxidative stress during 1 hour. Experimental and control samples were analyzed by RNA-seq experiments.
Project description:Pseudomonas extremaustralis, an Antarctic bacterium, was grown at low oxygen conditions for 24h and then exposed to S-Nitrosoglutathione (GSNO)100 µM for 1 h. RNA from treated and control samples was isolated using the Trizol method. RNA quality was analyzed on the Agilent Bioanalyzer and rRNA depletion was performed using the RiboZERO kit (Illumina). Samples were validated using an Agilent 2100 Bioanalyzer (Agilent Technologies). Libraries were prepared with TruSeq RNA Library Prep Kit v2 (Illumina) and sequenced with the Illumina NextSeq 550 platform with a single-end protocol.
Project description:sRNA40 (a novel sRNA) was pulse-expressed and its effects studied by transcriptomic profiling in P. extremaustralis, an Antarctic bacterium. For this approach we built a plasmid-based system, where sRNA40 was cloned under the control of the heterologous araBp promoter, inducible by arabinose (pBAD18-sRNA40). P. extremaustralis carrying the empty plasmid pBAD (pBAD18) was used as a control. Both strains were grown at low oxygen conditions for 24 hours. Cells were harvested after 10 min of induction with 0.1% arabinose. RNA was isolated using the Trizol method. RNA quality was analyzed on the Agilent Bioanalyzer and rRNA depletion was performed using the RiboZERO (Illumina). Samples were validated using an Agilent 2100 Bioanalyzer (Agilent Technologies). Libraries were prepared with TruSeq RNA Library Prep Kit v2 (Illumina) and sequenced with the Illumina NextSeq 550 platform with a single-end protocol.
Project description:In this work we analyzed the whole transcriptome of early exponential cultures growing at 8 degree C and 30 degree C by RNA deep-sequencing technology.
Project description:Because of severe abiotic limitations, Antarctic soils represent simplified ecosystems, where microorganisms are the principle drivers of nutrient cycling. This relative simplicity makes these ecosystems particularly vulnerable to perturbations, like global warming, and the Antarctic Peninsula is among the most rapidly warming regions on the planet. However, the consequences of the ongoing warming of Antarctica on microorganisms and the processes they mediate are unknown. Here, using 16S rRNA gene pyrosequencing and qPCR, we report a number of highly consistent changes in microbial community structure and abundance across very disparate sub-Antarctic and Antarctic environments following three years of experimental field warming (+ 0.5-2°C). Specifically, we found significant increases in the abundance of fungi and bacteria and in the Alphaproteobacteria-to-Acidobacteria ratio. These alterations were linked to a significant increase in soil respiration. Furthermore, the shifts toward generalist or opportunistic bacterial communities following warming weakened the linkage between bacterial diversity and functional diversity. Warming also increased the abundance of some organisms related to the N-cycle, detected as an increase in the relative abundance of nitrogenase genes via GeoChip microarray analyses. Our results demonstrate that soil microorganisms across a range of sub-Antarctic and Antarctic environments can respond consistently and rapidly to increasing temperatures, thereby potentially disrupting soil functioning.
Project description:The ability of the Antarctic microarthropod, Cryptopygus antarcticus (Collembola, Isotomidae), to survive low temperatures has been well studied at the physiological level. These investigations have indicated the importance of the moulting process in conferring this ability. This study investigated gene expression in groups of C. antarcticus that have distinct differences in their ability to survive low temperatures. A microarray containing 5,400 C. antarcticus expressed sequence tags was used to investigate gene expression differences between groups of animals with different supercooling points (SCP), and to low temperatures close to their SCP. By demonstrating the involvement of moulting genes in the differential survival of two groups of C. antarcticus with distinct SCPs, the results of this investigation add support to the role moulting plays in conferring cold tolerance in C. antarcticus.