Hidemasa Hidaka

Molecular cloning of the gene for indolepyruvate decarboxylase from Enterobacter cloacae.

SummaryAlthough indole-3-acetic acid (IAA) is a well-known plant hormone, the main IAA biosynthetic pathway from l-tryptophan (Trp) via indole-3-pyruvic acid (IPyA) has yet to be elucidated. Previous studies have suggested that IAA is produced by Enterobacter cloacae isolated from the rhizosphere of cucumbers and its biosynthetic pathway may possibly be the same as that in plants. To elucidate this pathway, the IAA biosynthetic gene was isolated from a genomic library of E. cloacae by assaying for the ability to convert Trp to IAA. DNA sequence analysis showed that this gene codes for only one enzyme and its predicted protein sequence has extensive homology with pyruvate decarboxylase in yeast and Zymomonas mobilis. Cell-free extracts prepared from Escherichia coli harboring this gene could convert IPyA to indole-3-acetaldehyde (IAAld). These results clearly show that this pathway is mediated only by indolepyruvate decarboxylase, which catalyzes the conversion of IPyA to IAAld.

Review Article: Fructooligosaccharides Enzymatic Preparation and Biofunctions

I. INTRODUCTION Recently the study of oligosaccharides has been extensively pursued in Japan after the findings of the remarkable biofunctions and usefulness of fructooligosac-charides for human health, improving the intestinal microflora and importance in livestock nutrition.

The effects of undigestible fructooligosaccharides on intestinal microflora and various physiological functions on human health

Fructooligosaccharides , containing 1-kestose (GF2), nystose (GF3) and fructofuranosylnystose (GF4), are found undigestible and to be selectively utilized by beneficial intestinal bacteria, particularly by Bifidobacteria. An increased population of beneficial intestinal bacteria would help to improve constipation to reduce the production of putrefactive substances .

Phosphopeptides in Rat Intestinal Digests after Ingesting Casein Phosphopeptides

Phosphopeptides in Rat Intestinal Digests after Ingesting Casein Phosphopeptides Masao Hirayama, Kyoko Toyota, Hidemasa Hidaka & Hiroshi Naito To cite this article: Masao Hirayama, Kyoko Toyota, Hidemasa Hidaka & Hiroshi Naito (1992) Phosphopeptides in Rat Intestinal Digests after Ingesting Casein Phosphopeptides, Bioscience, Biotechnology, and Biochemistry, 56:7, 1128-1129, DOI: 10.1271/bbb.56.1128 To link to this article: http://dx.doi.org/10.1271/bbb.56.1128

Production and Characteristics of Fructo-Oligosaccharides

Fructo-oligosaccharides are short-chain fructans with a terminal or in-chain glucose moiety and are found in many plant species, such as onion, edible burdock, asparagus and others. A mixture of fructo-oligosaccharides, namely 1-kestose (GF2), nystose (GF3), and 1-fructofuranosylnystose (GF4), is commercially produced from sucrose through the transfructosylating action of an enzyme from Aspergillus niger. Fructo-oligosaccharides possess useful physical and physiological properties and good sensory qualities which make them widely applicable in food- and feedstuffs. They are stable at neutral pH and at temperatures up to 140 °C, and have a sweetness of good quality. Because fructo-oligosaccharides are non-digestible, after ingestion they pass through the small intestine without being metabolized, and thus reach the large intestine unaltered, where they are selectively utilized by bifidobacteria of the intestinal microflora. Many studies have shown that fructo-oligosaccharides relieve constipation, improve the blood lipid composition in hyperlipidaemia, and suppress the production of intestinal putrefactive substances in both animals and humans. These results indicate the usefulness of fructo-oligosaccharides as a new sweetener, and as a healthy ingredient of foods and feeds.

Submerged Citric Acid Fermentation of Blackstrap Molasses: Part I. Isolation of a Producing Stratin Utilizing Blackstrap Molasses and the Effects of Incubation Temperature

Isolation and screening tests were carried out in order to find microorganisms which were able to produce citric acid directly from blackstrap molasses. Some strains were obtained which accumulate considerable quantities of citric acid. Certain temperature changes during the course of incubation were found to increase the yield of citric acid.The present investigation was undertaken to see if a simple method could be found to improve the yield of citric acid from blackstrap molasses, and we could obtain the yield of more than 70% from the untreated molasses using a newly isolated strain of Asp. niger.