Kei Arima

Microbial Transformation of Sterols: Part I. Decomposition of Cholesterol by MicroorganismsPart II. Cleavage of Sterol Side Chains by Microorganisms

Cholesterol decomposing ability of 1589 microbial strains was examined. Two hundreds and thirty six strains from actinomycetes, bacteria, molds, and yeasts were found capable of oxidizing cholesterol into cholestenone. Cholesta-1,4-dien-3-one was produced by 5 strains of Streptomyces. The complete decomposition of cholesterol molecule was observed in the genera: Arthrobacter, Bacillus, Brevibacterium, Corynebacterium, Microbacterium, Mycobacterium, Nocardia, Protaminobacter, Serratia, and Streptomyces. α,α′-Dipyridyl and arsenite inhibited decomposing enzymes giving rise to cholestenone, cholesta-1,4-dien-3-one, and an intermediate probably devoid of the sterol side chain.Selective cleavage of the side chains of various sterols at C-17, giving rise to androsta-1,4-diene-3,17-dione (ADD), occurred in the presence of α,α′-dipyridyl by microorganisms of the following genera: Arthrobacter, Bacillus, Brevibacterium, Corynebacterium, Microbacterium, Mycobacterium, Nocardia, Protaminobacter, Serratia, and Strept...

Restriction and modification in Bacillus species

SummaryHost specific restriction was detected in 13 Bacillus strains, when 63 strains of Bacillus subtilis and 15 other Bacillus strains were tested with phage Φ105C. These 13 strains were classified into 8 groups (M,H,C,N,E,F,G,P) by the type of restriction. M-type strains (B. subtilis Marburg 168, its derivatives, and two other strains) showed relatively weak restriction, restricting Φ105C from other groups of Bacillus by ratios of 10-1 to 10-3. Strains of groups H,C,N,E,F,G, and P restricted Φ105C from other groups by ratios of 10-2 to 10-8. It was confirmed with some of the strains that type-specific modification was endowed only by the last host. Furthermore, we isolated one restriction deficient mutant of B. subtilis marburg 168-YS11, which had also lost its modification phenotype.

Pectic Enzymes in the Clarification of Apple Juice: Part I. Study on the Clarification Reaction in a Simplified Model

To know the role of pectic enzymes in the clarification reaction of apple juice, a simplified model for apple juice, that is, aqueous re-suspension of ultracentrifugal precipitates of apple juice, was employed. It was found that the precipitates (i.e., suspended materials) contained 36% of protein and that the surface of the suspended materials was negatively charged at pH 3.5. Positively charged colloids at pH 3.5 such as gelatin enhanced the clarification reaction or mutually coagulated with the suspended materials. While negatively charged colloids at pH 3.5, such as sodium alginate completely inhibited the clarification reaction. The direct participation of pectic enzymes in the clarification of apple juice was shown, and a supposed mechanism of the enzymic clarification was presented.

Studies on bacterial urate:oxygen oxidoreductase I. Purification and properties of the enzyme

Abstract 1. 1.The urate oxidase (urate:oxygen oxidoreducatse, EC 1.7.3.3 of Arthrobacter pascens which was isiolated from soil was purified. 2. 2.The purified enzyme has shown to be homogeneous by ultracentrifugation and Tiselius electrophoresis, and some properties were investigated. 3. 3.Ultraviolet spectrum and MIchaelis constant ( K m ) were shown to be different from those of the urate oxidase of pork liver. 4. 4.The enzyme has a pH optimum at 9.2 and is stable at high pH. 5. 5.The enzyme showed reversible inactivation in low buffer concentration, which was considered to be parallel with the conformational change of the enzyme protein from some evidence obtained. 6. 6.Among the effects of metals and chelating agent on the activity of the enzyme, Cu 2+ showed remarkable inhibition and Fe 3+ showed slight stimulation. Strong inhibitory action of neo-cuproin (2,9-dimethyl-1,10-phenanthroline) and weak inhibitory action of o -phenanthroline and α,α′-dipyridyl were observed. These properties of A. pascens enzyme were compared with the liver enzyme.

Inhibitory effect of sucrose ester of lauric acid on the growth of Escherichia coli.

Abstract Effect of fatty acids and their derivatives on the growth of E. coli was studied. Lauric acid showed the strongest inhibition among the fatty acids tested. Most of the derivatives of lauric acid were less effective than lauric acid but its sucrose ester inhibited the bacterial growth to the greater extent than lauric acid itself. Addition of sucrose ester immediately stopped the bacterial growth independent of the time of addition.

A novel protoplast-bursting factor (surfactin) obtained from Bacillus subtilis IAM 1213: I. The effects of surfactin on Bacillus megaterium KM

Abstract 1. 1. Surfactin burst more than 90% of protoplasts prepared from Bacillus megaterium KM at a concentration of 14 μg/ml. 2. 2. Surfactin released intracellular ultraviolet-absorbing substances from intact cells without any decrease of their turbidity. 3. 3. Surfactin inhibited glucose oxidation of cells grown in low Pi medium. 4. 4. Surfactin inhibited the synthesis of alkaline phosphatase (orthophosphoric monoester phosphohydrolase, EC 3.1.3.1).

A novel protoplast-bursting factor (surfactin) obtained from bacillus subtilis IAM 1213. II. The interaction of surfactin with bacterial membranes and lipids.

Abstract 1. 1. The protoplast-bursting activity of surfactin was neutralized by membrane fractions which had been solubilized in dilute alkali solution. 2. 2. After digestion of the membranes by trypsin, the residual fraction, containing high contents of lipids, still retained neutralizing activity against surfactin. 3. 3. Phospholipids such as phosphatidylethanolamine and phosphatidylcholine neutralized the activity of surfactin.

Milk Clotting Enzyme from Microorganisms

Out of some 800 strains of microorganisms, a potent fungus for milk clotting enzyme was isolated from soil during the course of screening tests and was identified as one of strains of Mucor pusillus Lindt. Satisfactory results were obtained in cheese making experiments with this enzyme which could be produced effectively by solid culture on wheat bran at 30°C for about 70 hrs.The balance between milk clotting activity and proteolytic activity of this enzyme resembled very much to that of rennet.Microbial rennet from Mucor pusillus F-27 was obtained with high productivity by solid culture followed by water extraction. The enzyme could be precipitated by salting out with ammonium sulfate and also by mixing with various water-miscible organic solvents such as ethanol, methanol or acetone.This enzyme is one of acid proteases having its optimal pH for milk casein digestion around 3.5. The ratio of milk clotting activity to proteolytic activity of this enzyme resembled that of calf rennet than those of other pr...

Purification of Prorennin mRNA and Its Translation in Vitro

Prorennin-specific messenger ribonucleic acid (mRNA) has been purified by a combination of sizing techniques, including Sepharose 2B chromatography and sucrose density gradient centrifugation, and affinity chromatography with poly (U)-Sepharose, from total nucleic acid extracted from dry ice-pulverized, fourth stomach of a calf. This mRNA bound to poly (U)-Sepharose, indicating that it contained a poly (A) sequence. The total translation product in the mRNA-dependent wheat germ system, upon addition of this mRNA, was identified as authentic prorennin by gel electrophoresis. The molecular weight of this mRNA was about 3.5 × 105 as determined by gel electrophoresis. These results indicate that the synthesis of prorennin is directed by this mRNA 1,020 nucleotides in length and requires the full coding capacity of the molecule.

Wetting of fibrin plate and apparent promotion of fibrinolysis by surfactin, a new bacterial peptidelipid surfactant

Aus Kulturen vonBacillus subtilis wurde Surfactin, eine neue Substanz, isoliert und aufgeklärt. Es handelt sich um ein Peptidlipid, welches netzende Eigenschaften besitzt und dadurch die Fibrinolyse beschleunigt.