Nagayo Ota

X-Ray crystal structure of the copper (II) complex of mugineic acid, a naturally occurring metal chelator of graminaceous plants

The X-ray crystal structure of the copper complex of mugineic acid shows that the ligant molecule co-ordinates with the copper ion in a hexadentate fashion, forming a distorted octahedral geometry.

Determination of germanium in different media by atomic absorption spectrometry with electrothermal atomization

Abstract Effectsof acids, alkalis or salts on the atomic absorption spectrometry (electrothermal atomization) of germanium are described. Most of the species tested interfere with the absorption. The mechanisms of the interferences were investigated by using tantalum-coated and standard graphite tubes. The results showed that positive interferences are due to inhibition of the reaction of germanium dioxide with carbon to form volatile GeO 3 and that suppressive interferences are due to physical occlusion effects. The addition of sodium hydroxide to the sample solution provides a very sensitive analysis (0.004 ppm for 1% absorption) for germanium without matrix interferences. This is probably due to the formation of stable Na 2 GeO 3 during the ashing step in the presence of sodium hydroxide.

Protein chemotaxonomy of genus Datura: Identical amino acid sequence of ferredoxin from two varieties of Datura stramonium

The complete amino acid sequence of the respective [2Fe-2S] ferredoxins from two varieties of Datura stramonium, D. stramonium var. stramonium and D. stramonium var. tatula, have been determined by automated Edman degradation of the entire Cm-protein and of the peptides obtained by tryptic digestion and CNBr treatment. The ferredoxins from the two plants exhibited identical amino acid sequences, suggesting a very close taxonomic relationship between the two. This result supports the proposal by Blakeslee and others that these plants, at first named by Linnaeus as two distinct species, i.e. D. stramonium L. and D. tatula L., should be considered two varieties of a single species.