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The aminoacyl-tRNA synthetases (AARSs) and their relationship to the genetic code are examined from the evolutionary perspective. Despite a loose correlation between codon assignments and AARS evolutionary relationships, the code is far too highly structured to have been ordered merely through the evolutionary wanderings of these enzymes. Nevertheless, the(More)
The phytohormone auxin controls processes such as cell elongation, root hair development and root branching. Tropisms, growth curvatures triggered by gravity, light and touch, are also auxin-mediated responses. Auxin is synthesized in the shoot apex and transported through the stem, but the molecular mechanism of auxin transport is not well understood.(More)
In this study we investigated the kinetics of the gravitropic response of the Arabidopsis mutant rgr1 (reduced root gravitropism). Although the rate of curvature in rgr1, which is allelic to axr4, was smaller than in the wild type (ecotype Wassilewskija), curvature was initiated in the same region of the root, the distal elongation zone. The time lag for(More)
5-aminolevulinic acid (ALA) is a precursor in the biosynthesis of tetrapyrroles including chlorophylls and heme. The formation of ALA involves two enzymatic steps which take place in the chloroplast in plants. The first enzyme, glutamyl-tRNA reductase, and the second enzyme, glutamate-1-semialdehyde-2,1-aminomutase, are encoded by the nuclear HEMA and GSA(More)
Post-transcriptional modifications in archaeal RNA are known to be phylogenetically distinct but relatively little is known of tRNA from the Methanococci, a lineage of methanogenic marine euryarchaea that grow over an unusually broad temperature range. Transfer RNAs from Methanococcus vannielii, Methanococcus maripaludis, the thermophile Methanococcus(More)
The nucleotide sequences of a Schizosaccharomyces pombe opal suppressor serine tRNA gene (sup9-e) and of 12 in vivo-generated mutant genes, which have lost the ability to suppress UGA mutations, have been determined. Analysis of the expression of these genes in Saccharomyces cerevisiae in vitro and in vivo systems has revealed defects in tRNA gene(More)
A wheat genomic library was screened with two synthetic oligonucleotides (24 and 25 bases in length) complementary to a partial cDNA clone encoding a glutenin gene [Thompson et al. (1983) Theor. Appl. Genet. 67, 87-96]. Glutenins are large molecular weight aggregated proteins of grain endosperm, and major determinants of bread making quality of wheat. Of(More)
The genome sequence of the genetically tractable, mesophilic, hydrogenotrophic methanogen Methanococcus maripaludis contains 1,722 protein-coding genes in a single circular chromosome of 1,661,137 bp. Of the protein-coding genes (open reading frames [ORFs]), 44% were assigned a function, 48% were conserved but had unknown or uncertain functions, and 7.5%(More)