coli K strain, insertion of an 8-bp sequence (Makino et al., 1991). Interestingly, their activation occurs after prolonged incubation on media containing methylphosphonate as the sole source of phosphorus (Makino et al., 1991). This phenomenon suggested that E. coli might utilize a Pi export-based method for maintaining Nutlin-3a ic50 the intracellular Pi concentration in response to some environmental stimuli. Further experiments are needed to understand the mechanism of YjbB activation and its relationship with the ‘phosphate balance’ between Pi and polyP. This work was supported by a Grant-in-Aid for JSPS Fellows from the Ministry of Education, Culture, Sports, Science and
Technology, Japan. We are grateful to the National BioResource Project (National Institute of Genetics, Japan) for the E. coli strains from the KEIO collection. Table S1. DNA primers. Please note: Wiley-Blackwell is not responsible for the content or functionality of any
supporting materials supplied by the authors. Any queries (other than missing material) should be directed to the corresponding author for the article. “
“Comparative genomic studies on several thermophilic archaea and bacteria revealed that a set of coordinated changes are associated with organisms adapted to a higher temperature, among which the dinucleotide composition of genomic DNA, pattern of codon usage and amino acid composition of the proteomes reveal subtle differences between thermophilic and mesophilic organisms. In this context, we have analyzed LDK378 all tRNA sequences present in the complete genome sequences of 57 organisms belonging to psychrophiles, meophiles, thermophiles and hyperthermophiles. The presence of distinct selective constraints was revealed in the number and distribution of tRNAs and in their folding patterns, which could be correlated with the optimal growth temperature. The tRNA contents of thermophiles very were found to be significantly less compared with the two other groups, whereas the tRNA genes of thermophiles exhibit a much higher guanine plus cytosine content.
Analysis of the entire data set revealed that tRNAs from thermophiles showed greater structural stability at higher temperatures compared with the other two groups. Repeated cluster analysis applied to two sets of data from tRNA folding, the free energy of folding (dG) and the melting temperature (Tm), indicated that the thermophiles always had a tendency to cluster together. The normal growing conditions for a microorganism require an environment with adequate levels of available water, nutrients and salts, neutral pH, 1 atm air pressure and a temperature ranging from 20 to 40 °C. These are the optimum conditions for the growth of a microorganism, but there are groups of organisms that survive in extreme environments and are known as extremophiles. Microorganisms that grow above 55 °C and below 20 °C are called thermophiles and psychrophiles, respectively, the remainder being called mesophiles.