Genetic Control of the Rate of α-Amylase Synthesis in Bacillus subtilis

Abstract

MATERIALS AND METHODS Bacterial strains. Strains of B. subtilis used in this study were derivatives of strain 168 of Burkholder and xiles (2). Strains 6160 (metB5 purB6 trp-160 amyEm+ amyRl) and 1-131 (met his aro-116 amyEm+ amyRl) were donated from Y. Ikeda and S. Yuki, respectively. Strain NA64 (metB5 purB6 410

Extracellular enzyme synthesis in the genus Bacillus.

“…The genotypes would be: amyEm amyRI; amyEm amyR2; amyEn amyRI; amyEn amyR2. Yamaguchi et al (341) have prepared four such strains and studied them in detail. It was found that the a-amylase of isogenic strains carrying amyRI or amyR2 were serologically and biochemically identical regardless of the types of enzyme.…”

“…Therefore, the amyR locus could not be part of the amyE gene possibly affecting the specific activity of the enzyme but must, in fact, be a control element dictating the rate of synthesis of the enzyme. Furthermore, amyR was shown to have no effect on the production of either extracellular protease or RNase but was specific for a-amylase (341). The relative location of amyR to amyE has been determined by genetic crosses between amyE mutants with amyRI or amyR2 strains.…”

Increased secretion of α-amylase from Bacillus subtilis caused by multiple copies of α-amylase gene from B. amyloliquefaciens is not further increased by genes enhancing the basic level of secretion

“…amylosacchariticus [1 ], and the a-amylase produced by it is of a different enzymatic type [18,19]. Another possibility is that amyR-n and arnyR-sc, which are closely linked to the structural gene of a-amylase [2,3], are cis-acting controlling regions and while in the chromosome cannot affect the a-amylase gene in the plasmid. On the other hand the high level of transcription and translation of the plasmid-borne c~-amylase gene may already be rate-limiting.…”

“…amylosacchariticus. Thus amyR-s, arnyR-n and amyR-sc replace amyR 1, amyR 2 and amyR 3 used previously [2,4]. direction of the construction of the next strain, tf, transformation; NNNG, mutagenization with N-methyl-N-nitroso-N'-nitroguanidine as in [17] and screening for his.…”

“…amylosacchariticus. In all of these species amyR is closely linked to the structural gene of a-amylase (amyE) whereas amyS is not [1][2][3][4]. The effect of amyR and amyS genes is synergistic [4].…”