Effect of riboflavin and riboflavin 2', 3', 4', 5'-tetrabutyrate on microsomal lipid peroxidation in vitro was studied. Riboflavin-tetrabutyrate decreased the lipid peroxide formation measured by thiobarbituric acid reaction and oxygen uptake, and prevented enzyme inactivation at the same time. Riboflavin showed a similar effect, but the effect was less than that of riboflavin-tetrabutyrate. The antioxidative and enzymeprotective effects of flavins were discussed in connection with lipid metabolism in vivo.
Methylenetetrahydrofolate dehydrogenase (EC 188.8.131.52) which is responsible for the enzymatic convertion of 5, 10-methylene-H4FA to 5, 10-methenyl-H4FA was found in various plant tissues. The enzyme was partially purified from pea seedlings and some of its properties were investigated. The enzyme was purified about 40-fold by fractionation with ammonium sulfate and gel-filtration. The optimum pH was 7.8. 5, 10-Methylene-H4FA and NADP were specifically required in the enzymatic reaction. Their Km values were 3.5×10-4M and 5.1×10-5M, respectively. Intracellular distribution of some folate-linked enzymes, i.e., methylenetetrahydrofolate dehydrogenase, formyltetrahydrofolate synthetase, methenyltetrahydrofolate cyclohydrolase, and phosphoribosylaminoimidazolecarboxamide formyltransferase, in pea seedlings were investigated. Major portions of these enzymes were located in the soluble fraction, while some activities of these enzymes were significantly detected in mitochondrial or microsomal fraction. A possible pathway for the synthesis and metabolism of folate coenzymes in plants is discussed.
Young weanling albino rats were pair fed with control and thiamine deficient diets for five weeks. The analyses of skins and granulomas showed that, compared with the control, the thiamine deficient group had a decrease in the neutral salt soluble, insoluble, and total collagen contents. The incorporation of glycine-1-14C into the skin collagen and the free glycine content of skins were also decreased. There was no change in the RNA and DNA contents of skins and granulomas. The urinary excretion of hydroxyproline or plasma hydroxyproline was not affected. The results suggest that there is a reduction of collagen synthesis in thiamine deficiency.
Studies were carried out on the formation of biodegradative L-threonine deaminase (EC 184.108.40.206) in resting cells of Escherichia coli. The results obtained are as follows: (1) The enzyme level was increased by adding L-threonine together with yeast extract to the cell suspension. (2) In the course of the enzyme formation, the addition of chloramphenicol or glucose to the medium resulted in instantaneous cessation of the enzyme synthesis. (3) Yeast extract could be partially replaced by casamino acids. A mixture of amino acids whose composition is similar to that of milk casein was also effective. (4) Omission of L-serine from the mixture caused an almost complete loss of the activity, indicating that L-serine as well as L-threonine was essentially required for the enzyme formation. (5) Other amino acids were also needed for the enzyme synthesis, although individual omission of them had a slight influence compared with that of L-serine.
Susceptibility to TSC1 (an antagonist of vitamin B6) was compared in seven animal species together with the protective effect of B61 on the induction of convulsions. Susceptibility to TSC occurred generally with the phylogenetic development of the brain of vertebrates as well as invertebrates. Abnormal behavior analogous to running fit in rat or mouse, which was thought to be a characteristic and activated form of locomotion, was also induced in every animal except the silkworm. In this experiment B6 was capable of arresting the induction of convulsions and abnormal behavior in guinea pig and gold-fish.
Male and Female albino rats (wistar strain) were pair fed with laboratory stock diet and their hepatic and urinary ascorbic acid, dehydroascorbic acid and diketogulonic acid were determined and total ascorbic acid was determined in blood. Activities of ascorbic acid degrading enzymes such as dehydroascorbatase and 2, 3-diketoaldonate decarboxylase were studied in liver and kidney of male and female rats. In male rats there was significantly higher ascorbic acid with no significant alterations in the dehydroascorbic acid and diketogulonic acid contents of liver when compared to those of female rats. The content of ascorbic acid in urine of male rats was more, but there was no significant changes in the dehydroascorbic acid and diketogulonic acid contents in males. Total blood ascorbic acid content of male rats was found to be significantly higher than that of female rats. The activities of dehydroascorbatase and 2, 3-diketoaldonate decarboxylase in liver of male rats was also found to be higher. The renal 2, 3-diketoaldonate decarboxylase activity was also found to be comparatively higher in males. However there was no sex difference in the activity of renal dehydroascorbatase. Probable reasons for sex variation in ascorbic acid metabolism have been discussed.
In studies concerning the socio-economic development of the people in two villages in a resettlement area in Northeast Thailand, anthropometric methods, being used to study the nutritional status of preschool children, indicated that growth are below optimal by comparison with British standards. In comparison with local standards, growth rate was similar to that of healthy Thai children as determined in 1959 but below that of Bangkok kindergarten children (1969). The latter had growth rates similar to British standard whereas rural Thai children had growth rates similar to British children only in the first 10 to 12 months of life. Results from the anthropometric studies in determining nutritional status are compared with biochemical results. It was concluded that anthropometric measurements are easier to perform and yield information that agrees qualitatively with the general picture concerning nutritional status obtainable by biochemical methods.
Effects of protein deprivation and excessive administration of L-histidine on the accumulation of L-histidine in rat small intestine in vitro were investigated using tissue strips and rings. Compared with a 20% casein diet, a non-protein diet and a 5% casein + 5% L-histidine diet significantly enhanced the accumulation of L-histidine per unit wet weight of the tissue strips. The amount of endogenous L-histidine in the intestine of the animals fed on the excess L-histidine diet was extremely larger than that of animals fed on 20% casein and non-protein diets. Net accumulation per unit wet weight of the strips, calculated by taking into account the endogenous levels of L-histidine, was still significantly higher for rats fed on non-protein and excess L-histidine diets. However, the accumulations expressed in terms of the whole animal were identical irrespective of the dietary regimens. Also, with the intestinal rings no such significant difference as with the intestinal strips was observed among rats with different dietary regimens. It is speculated that dietary conditions affect intestinal absorption by modifying intestinal thickness rather than by influencing the mucosal function to accumulate amino acid.
The effect of protein-free diet on cellular growth of the liver and muscle, in terms of cell size (protein/DNA) and cell number (total DNA), in pregnant and nonpregnant rats was investigated. Slight but significant decreases in the size and number of liver and muscle cells were observed in both groups of rats when fed a protein-free diet ad libitum for three weeks. When rats received only 5 g of the proteinfree diet a day for three weeks, the total DNA in their liver and muscles decreased greatly. When these depleted animals were refed, the size and number of liver and muscle cells increased to normal levels within 10 to 14 days. Similar changes in cellular response to the nutritional impacts were observed in pregnant and nonpregnant animals.
General properties of the protease inhibitors in wheat and their distribution in germ, endosperm and bran were investigated. It was found that each part of wheat, germ, endosperm and bran, contains inhibitory activities against trypsin, α-chymotrypsin and pepsin. Gel electrophoresis of the germ extract revealed the presence of four trypsin inhibitors, three of which also had inhibitory activities against α-chymotrypsin. The endosperm portion was similarly shown to have three trypsin inhibitors, two of them having activities against α-chymotrypsin. One of the two trypsin inhibitors in bran also exhibited α-chymotrypsin-inhibitory activity. It was not, however, possible to identify pepsin inhibitors on the electrophotogram. The trypsin inhibitors are moderately heat stable, retaining 90% of original activity after heating at 80°C for 2 hr. The α-chymotrypsin inhibitors, on the other hand, were found to be rather heat sensitive, losing 50% of its original activity upon heating at 80°C for 30min. This is contrasted by pepsin inhibitor which fully retains its original activity after heating in boiling water for 2 hr. Finally, molecular weights of the inhibitors were estimated by SDS-gel electrophoresis.