Phosphorylation of two isozymes of (Na+ + K+)-ATPase by inorganic phosphate

The phosphorylation of two isozymes (alpha(+) and alpha) of (Na+ + K+)-ATPase by 32Pi was studied under equilibrium conditions in various enzyme preparations from rat medulla oblongata, rat cerebral cortex, rat cerebellum, rat kidney, guinea pig kidney, and rabbit kidney. In ouabain-sensitive (Na+ + K+)-ATPases such as the brain, guinea pig kidney, and rabbit kidney enzymes, ouabain stimulated the Mg2+-dependent phosphorylation at lower concentrations, while a higher concentration was required for the stimulation of rat kidney (Na+ + K+)-ATPase, an ouabain-insensitive enzyme. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that two isozymes of the brain (Na+ + K+)-ATPase were also phosphorylated by 32Pi in the presence of ouabain. The properties of the phosphorylation were compared between the medullar oblongata (referred to as alpha(+] and the kidney (referred to as alpha) (Na+ + K+)-ATPases. The steady-state level of phosphorylation was achieved faster in the kidney enzymes than in the medulla oblongata enzyme. Phosphorylation without ouabain was greater in the kidney enzymes than in the brain enzymes. Furthermore, the former enzymes were inhibited by K+ much more than the latter. These findings suggest that the two isozymes of (Na+ + K+)-ATPase differ in their conformational changes during enzyme turnover.     

Potentiation of pressor response to angiotensin II at the preoptic area in spontaneously hypertensive rat

Cardiovascular responses to angiotensin II(AII) at the preoptic area (POA) were compared between normotensive Wistar Kyoto rat (WKY) and spontaneously hypertensive rat(SHR) by measuring blood pressure and heart rate under unrestrained, conscious state via a catheter implanted chronically into the abdominal aorta and by injection of drugs into POA through a chronic guide cannula. AII injected into POA at doses of 0.3 ng and 1 ng produced a dose-dependent pressor response, accompanied with a slight decrease of heart rate, in both WKY and SHR. However, in SHR, the pressor response to AII was more than 2 times greater than that in WKY and was quick in onset and lasted about 30 min. When AII in combination with [Sar1, Ile8]-angiotensin II (0.5 microgram), an AII receptor antagonist, were simultaneously administered to POA, the pressor response to AII was strongly inhibited in both WKY and SHR. The results suggest that the pressor response to AII due to its receptor stimulation at POA is markedly potentiated in SHR.     

Metabolomics for metabolically manipulated plants: effects of tryptophan overproduction

Advances in molecular breeding technologies have enabled manipulation of the concentrations of specific plant components by modifying the genes that play a key role in their production. This has provided new opportunities to enhance the nutritional quality of major crops. However, given that metabolic pathways form a highly integrated network, any alteration in a given biosynthetic pathway is most likely to effect secondary and unpredicted changes in the metabolite profile of other pathways. Metabolomics technologies can contribute to the efficient detection of such unexpected effects caused by genetic modification. This has relevance not only from the perspective of safety evaluations of newly developed crops, but to basic science focused on uncovering hitherto unknown regulatory mechanisms associated with the biosynthesis and catabolism of primary and secondary metabolites in plants. In this review, recent advances in plant metabolic engineering for the overproduction of tryptophan (Trp), one of the essential amino acids, are described. In particular, the efficacy of a transgene OASA1D that encodes a mutant anthranilate synthase (AS) α subunit of rice in specifically elevating levels of Trp without marked secondary effects on the metabolite profile of rice is demonstrated. Related topics, such as regulation of Trp biosynthesis, possible interactions between the biosyntheses of Trp and other aromatic amino acids, and translocation of Trp in are discussed based on findings derived from metabolomic analyses of Trp-overproducing transgenic plants.     

Salinity Decreases Nitrite Reductase Gene Diversity in Denitrifying Bacteria of Wastewater Treatment Systems

Investigation of the diversity of nirK and nirS in denitrifying bacteria revealed that salinity decreased the diversity in a nitrate-containing saline wastewater treatment system. The predominant nirS clone was related to nirS derived from marine bacteria, and the predominant nirK clone was related to nirK of the genus Alcaligenes.     

Familial occurrence of a syndrome with mental retardation,nasal hypoplasia,peripheral dysostosis,and blue eyes in Japanese siblings

Summary Two Japanese siblings, a 2-year-old girl and a 7-month-old boy, had a syndrome of mental retardation, severe nasal hypoplasia, peripheral dysostosis, and blue eyes. The mother showed nasal hypoplasia of lesser degree and a mild form of peripheral dysostosis. This disorder bears a striking similarity to acrodysostosis, but in view of certain novel features its relationship to the disease is uncertain. The mode of inheritance could be either dominant with variable expressivity or autosomal recessive.     

Cloning of cDNA for human T-cell replacing factor (interleukin-5) and comparison with the murine homologue.

We have cloned cDNA for T-cell replacing factor (interleukin-5), which replaces T-cell helper function for normal B cells which secrete immunoglobulin, from human T cell leukemia line, ATL-2, using mouse interleukin-5 cDNA as probe. Total nucleotide sequence of the cDNA (816 base pairs) was determined and compared with that of mouse interleukin-5 cDNA. The cloned cDNA encoded the interleukin-5 precursor of 134 amino acids containing an N-terminal signal sequence. Although the human interleukin-5 precursor is one amino acid longer than the murine homologue, the sizes of the mature proteins appear similar. The nucleotide and amino acid sequence homologies of the coding regions of human and murine interleukin-5 are 77% and 70%, respectively. Human interleukin-5 synthesized by the direction of the cloned cDNA induced immunoglobulin synthesis in human B cells stimulated by Staphylococcus aureus mitogen.