The platelets of vitamin E-deficient rats show a remarkable structural destruction of the mitochondria, mainly in the membrane, and a considerable decrease in the number of mitochondria. In addition, signi-ficant decreases are manifested in the numbers of microtubules, α-granulomers, dense bodies and glycogen particles, accompanied by re-markable vacuole formation. The longer the vitamin E-deficient period, the more remarkable the changes are. Rats deficient in vitamin E for 58 weeks showed the highest degenerative changes in the platelets.
Rats were fed either a thiamine-deficient diet or diets con-taining pyrithiamine or oxythiamine. When symptoms of thiamine deficiency appeared, the animals were injected intraperitoneally with [2-14C] pyruvate six to twelve minutes prior to sacrifice. Free glutamic and aspartic acids were isolated from liver and brain and degraded. The results indicate that, in thiamine-deficient or oxythiamine-treated rats, pyruvate metabolism in liver and brain is similar to that in normal animals. In contrast, pyrithiamine drastically decreases the oxidative decarboxyla-tion of pyruvate by rat liver.
A complex intermediate of the copper(II) ion with the ascorbate anion was detected by using a rapid scanning spectrophoto-meter with a stopped-flow apparatus. The intermediate was confirmed to be a copper(II) complex ion by electron paramagnetic resonance measure-ments. The dependence of the absorbance of the complex on the con-centrations of reactants and on the pH of the reaction solutions indicates that the complex is Cu(II)Ha+ where Ha is the ascorbate anion ligand. The absorption maximum, the molar absorption coefficient, and the formation constant of the complex are 410nm, 33±1 M-1 cm-1 at 420nm, and 42±6M-1, respectively. The values are comparable to those in the other metal complexes of the ascorbate anion.
The possibility whether guanine ribonucleotidyl-(3'-5')-adenosine (GpA) is accumulated or not was studied with the use of micro-organisms such as E. ashbyii (a non-flavinogenic strain), E. coil, S. cerevisiae and N. crassa, which produce riboflavin in a trace amount. (1) In a flavinogenic strain of E. ashbyii, riboflavin formation was stimulated fivefold in the presence of glucose (1%) compared with that in the control experiment without glucose. The presence of caffeine notice-ably restricted riboflavin formation during incubation of non-growing cells with or without glucose. Moreover, the addition of caffeine to the glucose-free medium brought about marked accumulation of GpA in the cells. (2) In a non-flavinogenic strain of E. ashbyii, riboflavin formation was remarkably slight under normal conditions. The effect of glucose and caf-feine on flavinogenesis in the same strain was much smaller than that in the flavinogenic strain except for the case of the glucose-free medium supple-mented with caffeine. However, compound (GpA) never accumulated in the strain, even under conditions permitting a large amount accumulation of GpA in a flavinogenic strain. (3) The other organisms, E. coil, S. cerevisiae and N. crassa, did not accu-mulate GpA in the cells under the same conditions as those with a high flavinogenic strain of E. ashbyii. (4) The results obtained indicated that a dinucleotide, GpA, is a com-pound closely related to the biosynthesis of riboflavin.
The addition of dimeric diacetyl to Eremothecium ashbyii caused simultaneous accumulation of two green fluorescent compounds with the inhibition of riboflavin formation in non-growing cells. One compound, referred to as Compound G1, was identified as 6, 7-dimethyl-8-ribityllumazine as reported previously and the other is referred to as Compound G2. The latter compound was considered to be 6-methyl-7-(2-hydroxy-2-methyl-3-oxobutyl)-8-ribityllumazine because a violet fluo-rescent compound, 6-methyl-7-hydroxy-8-ribityllumazine was derived from Compound G2 in the presence of p-quinone and because the known action mechanism of dimeric diacetyl as a trapping agent of possible intermediates in the biosynthetic pathway. The results indicate that an immediate intermediate to 6, 7-dimethyl-8-ribityllumazine in the biosynthetic pathway of riboflavin is 4-ribitylamino-5-amino-2, 6-dihydroxypyrimidine, whose pyrimidine portion is derived by the elimination of a dimeric diacetyl fragment from the molecule of the isolated lumazine.
WILLIAMS et al. (1) investigated the changes in amounts of total mitochondrial protein and cytochromes in the liver of rats fed a protein-free diet for a long period, and found that there was a marked similarity between changes in amount of total mitochondrial protein and that of cytochromes. Present experiments were performed to clarify whe-ther under a more mild protein-deficient state the relationships found by Williams are applicable or not by investigating the changes in contents of cytochromes per unit amount of mitochondrial protein when rats were fed a low casein diet. A 4% casein diet was used as a low casein diet, and a 25% casein diet was used as a control diet. Rats were fed the test diets for 70 to 90 days. The results show that the contents of all cytochromes a, b, and c1+c assayed and expressed as nmoles per mg of mitochondrial protein were significantly higher in rats fed a low casein diet than those in rats fed a control diet. These results suggest that relationships found by Williams in a severe protein-deficient state would not be applicable in a more mild protein-deficient state.
A study on how EFA deficiency affects lipid metabolism of rat skin, especially lipid on skin surface, was made. The total amount of lipid on skin surface of rat increased due to EFA deficiency, but not signi-ficantly. The sterol ester in skin surface lipid was maintained at a normal level in a EFA deficient rat, but the free sterol level was higher than that of the control rat. The glycerides decreased markedly due to EFA defi-ciency. It was recognized that branched fatty acids increased in each lipid fraction on skin surface. It was considered that such changes in skin surface lipid were charac-teristic to skin. It was not predictable whether these changes resulted directly from EFA deficiency or secondary from the occurrence of dermal symptoms.
A study was made on whether or not the lability of protein generally correlates with its metabolic turnover rate. Two fractions of soluble protein were prepared from rat liver. Using the double isotope method, it was revealed that the fraction precipitated with half saturated ammonium sulfate had a larger turnover rate than the supernatant one. Both dietary protein depletion and starvation, though they significantly decreased total protein content, did not affect the ratio of the amount of protein in the precipitate to that of the supernatant fraction. These results suggested that both fractions, though they had a different turnover rates, were equally influenced by dietary protein depletion or fasting. In consequence, the results imply that the lability of protein does not neces-sarily in parallel with the metabolic turnover rate.
Folic acid and folate binding protein (FABP) concentrations were determined in 208 pregnant women as well as in 50 non-pregnant women. Serum folate levels in pregnant women were significantly lower than those of the non-pregnant group. Anaemic pregnant women also had lower serum folate concentrations than those of the non-anaemic pregnant women. Ninetyeight of 208 (47.1%) pregnant women had serum folate levels of less than 4ng/ml. No significant difference in red cell folate concentration between the pregnant and non-pregnant groups was demonstrated, and only 5 of 206 (2.4%) of pregnant women had red cell folate levels of less than 200ng/ml. Serum FABP levels in preg-nant women were also found to be significantly higher (p<0.001) than those of the non-pregnant women. These levels were also found to be higher in the anaemic pregnant group and in pregnant women with serum folate concentration less than 4ng/ml than those of the non-anaemic pregnant women and pregnant women with serum folate concentration higher than 4ng/ml, respectively. There was a direct relationship between the serum FABP levels and the gestation period. As the period of pregnancy advanced higher serum FABP levels were demonstrated. No correlation between the gravida and the serum FABP levels was found in this study.
The nutritive values of proteins in relation to their intake levels were evaluated by feeding adult male rats weighing 250g diets containing 0%, 0.39%, 0.78%, 1.56%, 2.34%, 3.90%, 7.79% and 15.58% lactalbumin or wheat gluten for three weeks. The biological values (BV) of both proteins were high at low levels of protein intake but decreased with increase in protein intake. The BY of wheat gluten was estimated to be about 100 at a level of intake of 1.56% but only 25 at a level of 15.58%. Similarly, the BV of lactalbumin decreased with increase in the protein level, being 67 at a level of 7.79%. The BVs of both proteins at low levels of dietary protein (below 2.34% of lactalbumin or 0.78% of wheat gluten) were apparently more than 100 because urinary N excretion was less than endogenous N. The BVs also decreased with time during the three-week test period. It is concluded that the BV of a protein is not a fixed value but varies with the experimental conditions especially with changes in the amount of intake, and that differences in the qualities of various proteins cannot be compared quantitatively at a single level of protein. The results were briefly discussed in relation to protein require-ments.