While many people may find 50°C (roughly 120°F) to be quite past their comfort zone, many thermophiles thrive between 45 and 122°C, with the toleration for the higher end (< 75°C) being hyperthermophiles. Thermophiles are organisms that can withstand – and sometimes even require – high temperatures to survive, hence their meaning “heat-loving.”

 Thermophiles are both prokaryotic and eukaryotic, though the microorganisms growing in the most extreme environments are archaea. Hot springs and deep-sea thermal vents can be found throughout the world, but a number of the studied thermophiles are concentrated in Yellowstone National Park, USA.

 What makes thermophiles so interesting is their ability to survive under high temperatures without denaturing their proteins. Thermophiles have special enzymes called extremozymes that are more tightly bound than enzymes at normal temperatures. Additionally, thermophile enzymes tend to have less glycine. Since glycine is the smallest and simplest amino acid, it typically allows proteins to be more flexible. Having less glycine in their structures would allow extremozymes to be more rigid and more resistant against extreme temperatures.

 Since extremozymes are able to function under extreme conditions, these enzymes have become well incorporated in biotechnological applications, such as PCR.

 Photo credit: harrell-enb150.blogspot.com

Primary transcriptome map of the hyperthermophilic archaeon Thermococcus kodakarensis

Prokaryotes have relatively small genomes, densely-packed with protein-encoding sequences. RNA sequencing has, however, revealed surprisingly complex transcriptomes and here we report the transcripts present in the model hyperthermophilic Archaeon, Thermococcus kodakarensis, under different…
Source:Primary transcriptome map of the hyperthermophilic archaeon Thermococcus kodakarensis

Primary transcriptome map of the hyperthermophilic archaeon Thermococcus kodakarensis

Background: Prokaryotes have relatively small genomes, densely-packed with protein-encoding sequences. #RNA sequencing has, however, revealed surprisingly complex transcriptomes and here we report the transcripts present in the model hyperthermophilic Archaeon, Thermococcus kodakarensis, under different physiological conditions. Results: Sequencing cDNA libraries, generated from #RNA isolated from cells under different growth and metabolic conditions has identified >2,700 sites of transcription initiation, established a genome-wide map of transcripts, and consensus sequences for transcription initiation and post-transcription regulatory elements. The primary transcription start sites (TSS) upstream of 1,254 annotated genes, plus 644 primary TSS and their promoters within genes, are identified. Most #mRNAs have a 5’-untranslated region (5’-UTR) 10 to 50 nt long (median = 16 nt), but ~20% have 5’-UTRs from 50 to 300 nt long and ~14% are leaderless. Approximately 50% of #mRNAs contain a consensus ribosome binding sequence. The results identify TSS for 1,018 antisense transcripts, most with sequences complementary to either the 5’- or 3’-region of a sense #mRNA, and confirm the presence of transcripts from all three CRISPR loci, the RNase P and 7S #RNAs, all t#RNAs and #rRNAs and 69 predicted sno#RNAs. Two putative riboswitch #RNAs were present in growing but not in stationary phase cells. The procedure used is designed to identify TSS but, assuming that the number of cDNA reads correlates with transcript abundance, the results also provide a semi-quantitative documentation of the differences in T. kodakarensis genome expression under different growth conditions and confirm previous observations of substrate-dependent specific gene expression. Many previously unanticipated small #RNAs have been identified, some with relative low GC contents (2,700 TSS, including almost all of the primary sites of transcription initiation upstream of annotated genes, plus many secondary sites, sites within genes and sites resulting in antisense transcripts. The T. kodakarensis genome is small (~2.1 Mbp) and tightly packed with protein-encoding genes, but the transcriptomes established also contain many non-coding #RNAs and predict extensive #RNA-based regulation in this model Archaeon. http://bit.ly/1t5HWl5 #BMC

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