SUMMARY: Polyamines are widely distributed in nature and known to have many roles in living organisms. We investigated the concentrations of polyamines together with inorganic nutrients during a summer bloom period in the Seto Inland Sea of Japan. Putrescine and spermidine were the major polyamines in the coastal seawater. The concentrations at 1 m depth varied widely during the sampling period and ranged from 2.0 to 32.6 nM and 1.0 to 14.1 nM. Spermine concentrations were much lower than putrescine and spermidine. In addition, other polyamines (diaminopropane, cadaverine, norspermidine, homospermidine, norspermine) were also detected. Putrescine and spermidine seemed to be significant compounds in dissolved organic nitrogen in coastal seawater.

No abstract

A glutaminase from Aspergillus oryzae was purified and its molecular weight was determined to be 82,091 by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Purified glutaminase catalysed the hydrolysis not only of L-glutamine but also of D-glutamine. Both the molecular weight and the substrate specificity of this glutaminase were different from those reported previously [Yano et al. (1998) J Ferment Technol 66: 137-143]. On the basis of its internal amino acid sequences, we have isolated and characterized the glutaminase gene (gtaA) from A. oryzae. The gtaA gene had an open reading frame coding for 690 amino acid residues, including a signal peptide of 20 amino acid residues and a mature protein of 670 amino acid residues. In the 5'-flanking region of the gene, there were three putative CreAp binding sequences and one putative AreAp binding sequence. The gtaA structural gene was introduced into A. oryzae NS4 and a marked increase in activity was detected in comparison with the control strain. The gtaA gene was also isolated from Aspergillus nidulans on the basis of the determined nucleotide sequence of the gtaA gene from A. oryzae.