α-Amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD) (EC 126.96.36.199) was purified to a homogeneous state from hog kidney cytosol by ammonium sulfate fractionation, Butyl-Toyopearl 650, hydroxyapatite, DEAE-Sephadex, Toyopearl HW55, Superdex 200 and TSK-gel G3000SW chromatographies. The molecular weight of the enzyme was estimated to be 58, 000 by TSK-gel G3000SW gel filtration. The optimum pH (constant concentration) was 7.5. The Km for α-amino-β-carboxymuconate-ε-semialdehyde was 1.61×10-5M. The activity of purified enzyme was inhibited by some chemical modifying reagents such as monoiodoacetic acid and p-(chloromercuri)benzoic acid. A sulfhydryl group was deduced to exist in the active site of the enzyme.
We have reported that excess cystine feeding exaggerates the defects of dietary copper deficiency in rats by a mechanism not involving oxidative stress and altered copper status. This study was conducted to examine whether this exacerbation is caused by a mecha nism involving altered iron status and to compare the influences of cystine and cysteine feeding on the defects of copper deficiency. Male Wistar rats were fed copper-adequate or copper-deficient diet with supplementation of L-cystine or L-cysteine (2%) for 10 days or 21 days. Copper-deficient diet increased heart weight, caused anemia, reduced plasma iron and elevated liver iron. These defects were exacerbated by supplemental cystine. Cysteine feeding also exacerbated the defects of dietary copper deficiency including anemia, increased heart weight, and reduced plasma iron, although cysteine feeding had no influence on liver iron concentra tion. Supplemental cysteine reduced apparent absorption of iron, while supplemental cystine did not. These results suggest that cystine feeding enhances the defects of copper deficiency by a mechanism involving impaired mobilization of iron from liver into blood, and that cysteine feeding enhances the defects of copper deficiency by a mechanism involv ing reduced intestinal absorption of iron.
In order to determine the appropriate intake of docosahexaenoic acid (22: 6n-3, DHA), the potential changes in lipid peroxidation and antioxidant defense in serum and tissue as well as the changes in serum lipid levels were examined in rats by giving them diets containing graded levels of purified DHA (0, 1.0, 3.4 and 8.7 energy % in the diets) for 2 weeks. Serum a-tocopherol concentration decreased slightly but significantly even at the 1.0 energy %. Liver lipid peroxide levels as assessed by the thiobarbituric acid (TBA) value and chemiluminescence intensity augmented at the 3.4 energy % and more, and the a-tocopherol content significantly decreased in response to the increase in lipid peroxide levels. In the kidney, a slight but significant increase in TBA value was observed even at 1.0 energy % and higher. All the serum lipid levels as analyzed by total cholesterol, HDL-cholesterol, triacylglycerol (TG) and phospholipids (PLs) decreased as the dietary DHA level increased. These experimental results suggest that the dietary intake of DHA should be less than 1 energy % to avoid promoting deleterious influences such as serum and tissue lipid peroxidation and to ameliorate serum lipid levels.
Surfactant protein A (SP-A) is a major apo-protein of pulmonary surfactant, which lines the alveolar walls, lowering the surface tension to prevent lung collapse. Pregnant rats were divided into two groups which received a diet with either 5% or 20% protein from gestational day 9. By a sensitive immunoassay, SP-A levels in the fetal lungs and the amniotic fluid showed a dramatic increase with advancing gestation after the initial appearance on gestational day 18 in both diet groups. Significantly lower levels of SP-A in pregnant rats fed 5 % protein diet than those in pregnant rats fed 20% protein diet were observed in the fetal lungs on gestational day 21 and in the amniotic fluid on gestational days 20 and 21. The profiles of increased SP-A levels in the amniotic fluid reflected those in the fetal lungs during gestation. Immunohistochemical examination with anti-rat SP-A antibody at 21 days of gestation showed that the immunoreactive staining of bronchiolar epithelial Clara cells and alveolar type II cells were weaker in the fetal lung sections from pregnant rats fed 5% protein diet than in those from pregnant rats fed 20% protein diet. It is concluded that protein malnutrition in pregnant rats affects the biosynthesis of SP-A in the fetal lungs, which may have important consequences for prematurity and decreased respiratory functions in the neonatal lungs at birth.
Corn peptide (CP) was prepared from corn gluten meal by proteolysis with alkaline protease from alkalophilic Bacillus A-7. Free amino acids were not found in the CP product. Gel filtration on a Shodex OH-packed column revealed that the molecular weight distribution of the CP was less than about 2, 000, characteristic of dipeptides to decapeptides, i.e. oligopeptides. The amino acid pattern of CP was similar to that of corn gluten meal, which was rich in alanine and branched-chain amino acids, but poor in basic amino acids. The effect of the CP administration on alcohol metabolism was examined with SHR-SP, which were given ethanol orally through a gastric tube at the rate of 1.0g/kg. Prior administration of CP at 1.0g/kg resulted in fast disappearance of ethanol and its oxidative product acetaldehyde from the blood relative to the control without administration. Hence, it is suggested that CP, rather than its constituent amino acids such as alanine and proline, effectively takes part in enhancing the metabolism of ethanol as well as acetaldehyde.
Iron deficiency is the most important nutritional problem all over the world. Fluid milk is an attractive vehicle for iron fortification, since it is a food with a high nutritional value, accessible to the whole population and easy to be given to children. Fortification of this food with iron has the disadvantage of the interaction of the iron with the constitutive elements of milk, diminishing its bioavailability and changing its sensorial properties, making it unacceptable. Nowadays, this problem can be overcome by the implementation of a new technological procedure, which consists in the microencapsulation of the ferrous sulfate with lecithin, thus avoiding the interaction of iron with the food. The absorption obtained in mice for milk-ferrous sulfate was 7.9±3.2%, while for microencapsulated ferrous sulfate-milk the result was 11.6±4.5%. Comparing these data with those obtained with the ferrous ascorbate in water 13.1±4, 9% and ferrous sulfate in water 13.2±4.3%, both of them considered as reference standards, no statistically significant difference between them and the microencapsulated ferrous sulfate in milk can be observed. However, this difference becomes significant (p<0.01) when these products are compared to the non-encapsulated ferrous sulfate in milk. Rn the other hand, we demonstrated that this product is stable to heat-processing (100°C, 30min) and storage at a room temperature up to 6 months that lacteous products are usually submitted to.
Energy and nutrient requirements of younger people have been well studied, unlike that of centenarians. The average life span of the Japanese is the longest in the world, and the population of the very aged is rapidly growing. In addition, the average life span of Okinawan people is the longest in all of Japan. Their food habits also differ from other parts of Japan. To obtain basic dietary information, we surveyed 21 centenarians in Okinawa (17 women and 4 men). The dietary survey was done by one 24h recall method, as was done for centenarians living throughout Japan (3). The energy intake of the Okinawan centenarians living at home was about 1, 100 kcal/day for both sexes, which was similar to that of centenarians throughout Japan. Energy, some nutrient intakes and food consumption pattern (in terms of food groups) were different from those of the centenarians throughout Japan. We also measured their heights, weights, hematological values and activities of daily living (ADL). Comparison between the nutrient intakes and the recommended dietary allowances (RDAs) estimated for the centenarians showed that the estimated RDA of energy for the Okinawan centenarians might be less than their actual intakes.
Effects of capsaicin, a pungent principle of hot red pepper, on glycogen contents in the liver and skeletal muscle at rest and during exercise were studied in rats. The contents of glycogen in the liver and soleus muscle, and the concentrations of serum glucose, lactate, free fatty acid and glycerol were examined. Capsaicin was supplemented at 0.014% of the experimental diet. Each group of rats was fed the capsaicin-diet ad libitum for 7 days, and then both groups of rats were fed isoenergetic diets with or without capsaicin for 7 days. Rats were trained running with a treadmill for 14 days. At the final stage of the experiments, 1h running was loaded after the capsaicin diet or the control diet. The glycogen contents in the liver and soleus muscle were not significantly different between the capsaicin-diet group and the control-diet group after the meal and during exercise. The concentrations of serum glucose, lactate, free fatty acid and glycerol were not significantly different between the two dietary groups after the meal and during exercise. The results in this study suggest that the intake of capsaicin have little effect on glycogen contents in the liver and soleus muscle at rest and during exercise in rats previously fed a capsaicin-diet ad libitum for 1 week.