Isomaltooligosaccharides (IMO), a mixture of α-1, 6-glucosides, are produced enzymatically from starch for use as a new sweetener. They are a growth factor for human intestinal bifidobacteria. The effects of ingestion of IMO for 35 days on growth, organ weight, serum lipids, and saccharidase activities of rat jejunal mucosa were investigated. The digestibility of IMO was measured in models of the digestion system containing artificial gastric acid, rat intestinal mucosa, or human salivaric or hog pancreatic α-amylase. The ratios of body weight gain/food intake of the test chows suggested that the energy available to rats in IMO was about 80% that of maltose and sucrose. The serum levels of triacylglycerol and nonesterified fatty acids were significantly lower in rats fed 20% IMO. These results were similar to those obtained in rats fed chow containing fructooligosaccharide, which is nondigestible in the upper intestine and fermentable in the lower. The long-term ingestion of IMO did not induce isomaltase activity in the rat jejunal mucosa. IMO was not hydrolyzed by the in vitro digestion system except in the model containing rat intestinal mucosa. The hydrolysis ratio of IMO by rat intestinal mucosa was much lower than that of maltose or isomaltose. The results suggested that IMO is partly hydrolyzed by the enzyme of intestinal mucosa, but that the residual undigested part passes down to the lower intestine.
The effect of the Ascochlorin derivative AS-6, a new hypoglycemic agent, on calcium metabolism was studied in genetically obese diabetic mice, C57Bl/ksj-db/db (db/db). Sixteen male db/db mice and seven lean littermates were used. The db/db mice were allocated to two groups (n=8), one of which was fed a commercial chow (Nihon CLEA, CE-2) as was the lean group. The other db/db group was fed CE-2 chow containing 0.1% AS-6 for 10 days. Serum glucose levels in thed b/db controls showed significant (p<0.01) increases of 3.4 times as compared with the lean controls mice. When AS-6 was given, serum glucose was reduced by 23% as compared with the db/db controls mice. Urinary Ca excretion in db/db controls (30.9 ± 8.2 μg/day) was significantly (p<0.01) higher than in the lean controls (6.8 ± 0.6). AS-6 reduced urinary Ca levels by 61%. Urine Ca levels were correlated to serum glucose (r=0.727) and to urine glucose (r=0.910). Serum Ca levels in db/db controls were significantly (p<0.01) higher than in the lean controls (12.63 ± 0.22 vs. 11.63 ± 0.25 mg/dl). AS-6 significantly (p<0.01) reduced serum Ca levels by 9% as compared with the db/db controls. Serum insulin and calcitonin levels in db/db controls were 15.6 times and 6.6 times, respectively, the levels in the lean controls. AS-6 decreased calcitonin levels by 56% as compared with the db/db controls. There was a correlation between serum calcium and insulin in db/db treated with AS-6 or not (r=0.666). The results showed that db/db mice required much insulin release for blood glucose to decrease, that hyperinsulinemia may contribute to increased serum calcium levels, and that potentiation of insulin action by AS-6 lessens hyperglycemia and hypercalcemia in db/db mice.
Staphylokinase is a plasminogen-activating protein derived from Staphylococcus aureus. It converts plasminogen into plasmin efficiently, especially in the presence of fibrin. I studied the relationship between the structure and the fibrinolytic activity of staphylokinase produced in Escherichia coli. The amino acid sequence of the carboxyl terminus was found to be lysyl-lysine, the same as that predicted from the nucleotide sequence. The removal of two amino acid residues from the C-terminus or 10 amino acid residues from the N-terminus had no effect on the fibrinolytic activity. The removal of 26 amino acid residues from the N-terminus resulted in the complete loss of fibrinolytic activity, although the truncated peptide still bound with plasminogen.
Rice dietary fiber was prepared from defatted rice bran by treatment with protease, and its physical and chemical properties were investigated. Its water adsorption capacity, oil adsorption capacity, and settling volume in water was 10.89g, 8.21g, and 13.0ml, respectively, per gram of fiber. The fibers adsorbed agricultural chemicals, malathion and fenitrothion. In these properties, rice fiber was superior to cellulose and fibers from corn bran and wheat bran. Characteristics of the binding of minerals to neutral detergent fibers (NDF) from the three cereals investigated were studied. Calcium bound to each kind of NDF at about 2mg per gram of NDF, but more iron (6.03mg per gram of NDF) bound to the NDF of rice bran than to the other two NDFs tested. The iron bound to the NDF of rice bran was not readily released by conditions normally used in cooking, but it was released under simulated gastrointestinal conditions. The iron bound to rice fiber had no effect on the properties such as the water adsorption capacity of the fiber.
The effect of koji prepared with Aspergillus oryzae and beni-koji prepared with Monascus pilosus on blood pressure of spontaneously hypertensive rats (SHR) was studied. Male adult SHR were fed semi-purified chow containing 1% NaCl with 5_??_10% koji or 3_??_10% beni-koji for 3 weeks. The blood pressure of the animals fed one of the kojis was 7.15% lower than that of the control group. Beni-koji had a stronger hypotensive effect than koji. Koji and beni-koji did not affect blood glucose, plasma cholesterol, plasma triglycerides, or mineral metabolism. These results suggested that koji and beni-koji suppress rises in blood pressure. The mechanism of the effect did not involve Na/K ion-exchange in the gastrointestinal tract, which would inhibit Na absorption.