This study was undertaken to examine the effects of oxygen exposure on vitamin E deficiency in mice. After 20 hr of exposure to pure oxygen, 5 of 7 mice in the vitamin E deficient group died, but only 1 of 7 in the vitamin E supplemented group died. Pulmonary atelectasis and hemor-rhages were the common features in the mice that died. Of the surviving mice, those in the vitamin E deficient group had partial hemorrhages, but those in the control group had no significant pathological changes. A reduction in phospholipid and sulfhydryl groups was observed in the supernatant fractions of the lungs of vitamin E deficient mice. After oxygen exposure further reductions occurred in both groups of mice, but more predominantly in the vitamin E deficient group. In the sediment fraction of the lungs, similar changes were found in the phospholipids in the vitamin E deficient group before and after exposure to oxygen. The sulfhydryl groups in the sediment fractions were decreased signi-ficantly in the vitamin E deficient group after oxygen exposure, but they remained unchanged in the control group.

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A novel ultramicro microbioassay, amplified cultivation, was developed. The principle of the method holds true in microbioassays of all the sub-stances essentially required by microorganisms. Application of the method to analyses of PaA, biotin, and NiA with L. plantarum ATCC 8014 by the pulp disc method revealed an increase in sensitivity by a factor of 10 to 100 compared with the conventional methods.

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Male albino rats were fed thyroid powder (1%) and ascorbic acid, dehydroascorbic acid, and diketogulonic acid were determined in liver, kidney, and urine, while only total ascorbic acid was determined in blood, after 14 days. Activities of ascorbic acid-synthesizing enzymes D-glucurono-δ-lactone hydrolase, L-gulono-γ-lactone hydrolase, L-gulono-γ-lactone oxidase were estimated in liver. The activities of degrading enzymes dehydroascorbatase and 2, 3-diketoaldonate decarboxylase were studied in liver and kidney. In hyperthyroid rats there was a significant decrease in the ascorbic acid level and dehydroascorbic acid content of liver, and urine. On the other hand there was marked in-crease in the diketogulonic acid of liver and kidney. The content of ascorbic acid and dehydroascorbic acid in urine of hyperthyroid rats decreased significantly, while there was an increase in diketogulonic acid content. There was a slight decrease in the total ascorbic acid in blood. A significant decrease was found only in activities of L-gulono-γ-lactone oxidase, while no change in the activities of D-glucurono-δ-lactone hydrolase and L-gulono-γ-lactone hydrolase occurred. An appreciable increase in the activity of dehydroascorbatase, with unchanged activity of 2, 3-diketoaldonate decarboxylase, was observed in liver and kidney.

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In the irradiation of ergosterol, the effect of wavelength on the forma-tion of potential vitamin D₂ (the sum of pre-D₂ and vitamin D₂) was investigated. Monochromatic UV rays obtained from a spectroirradiator were used for the irradiations and the yield of potential vitamin D₂ was estimated by the GLC method as described previously (1). When an ergosterol solution in ethanol (1.0 mg/ml) was irradiated by mono-chromatic UV ray in the range 230-400mμ with the quantum of 4.0×10⁸ erg/cm², the figure of the relationship between yield of potential vitamin D₂ and wavelengths of irradiating UV rays showed a mountain shape with a maximum at 295mμ. Ultraviolet rays in the range 285-310mμ were more effective than the other rays for the formation of potential vitamin D₂ (yield: higher than 22%), whereas those either below 230mμ or above 330mμ were less effective (yield: lower than 3.5%). The gas chromatograms of TMS ethers of all the irradiated solutions showed the presence of peaks due to gyro- and isopyro-D₂ (thermal cyclized products of pre-D₂ and vitamin D₂), lumisterol₂, ergosterol and tachy-sterol₂, although their peak area ratios were very different. The irradiations by various monochromatic UV rays with different quanta of energy were also examined, and the ray of 295mμ with quanta of 2.1-6.4×10⁸ erg/cm² was found to give the best yields of potential vitamin D₂, between 31.5 and 33%. Further irradiations beyond the maxima effected a decrease in the yield.

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In order to obtain accurate information about the function of the ring-nitrogen of B₆ in the enzymatic reactions dependent on the vitamin, the reaction rate leading to α-proton elimination from amino acid substrate was compared between native enzyme and holoenzyme species, recon-stituted with pyridoxal phosphate N-oxide (PLP N-oxide), using a stopped flow method. In tryptophanase, the formation rate of the deprotonated Schiff's base (A_502nm complex) of the PLP N-oxide enzyme with L-alanine was about one-fifth of that of the native enzyme, being substan-tially consistent with the marked low catalytic activity of PL N-oxide in the corresponding nonenzymatic model reaction and of the PLP N-oxide enzyme in overall tryptophan degradation. This result stronglyy suggests that the electronegativity of the pyridinium-nitrogen plays a predominant role in the a-proton elimination from the substrate, one of the most important steps in overall reaction.
On the other hand, in aspartate aminotransferase (GOT) reaction, such a significant difference was not observed between the formation rate of deprotonated Schiff's base of native GOT with erythro-β-hydroxy-aspartate (A_492nm, complex) and that of the artificial GOT activated with PLP N-oxide. However, the reaction of PMP N-oxide form of GOT with α-keto acid proceeded at an extremely slow rate as compared with that of PMP form of GOT. These phenomena indicate that the lower V_max of overall GOT reaction catalyzed by the PLP N-oxide-bound holoenzyme would be accounted for by the marked smaller, reactivity of PMP N-oxide form with α-keto acid. These results strongly suggest that, in GOT, the α-proton elimination from substrate is mainly mediated by a nucleophilic attack of basic amino acid residue located at an ap-propriate position of enzyme protein and that the introduction of an oxygen atom into the pyridine-nitrogen of PLP results in a conforma-tional change of coenzyme analog-bound GOT which renders the interac-tion between PMP-form GOT with α-keto acid very difficult.

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A new derivative of 4-pyridoxic acid was produced when 4-pyridoxic acid was incubated with homogenates of rat liver. The successful isolation procedures of the compound from the incubation mixture consisted of charcoal treatment and column chromatography on DEAE- and P-cellulose. The compound was obtained in colorless planeary crystals: mp, 253-255°C (decomp.). It was identified as 5'-O-(α-D-glucopy-ranosyl)-4-pyridoxic acid based on spectral data and acid hydrolysis results. The structure of the compound was verified by enzymic analysis using α- and β-glucosidases.

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Prolonged incubation of maltose and pyridoxic acid with enzyme pre-paration from rat liver gave a new compound together with 5'-O-(α-D-glucopyranosyl)-4-pyridoxic acid. The purified compound was obtained as a colorless powder from the incubation mixture by isolation procedures consisting of charcoal treatment and column chromatography on DEAE-cellulose and Sephadex G-10. The compound, which was identified as 5'-O-(α-D-maltosyl)-4-pyridoxic acid, was produced through successive transfers of glucosyl groups from maltose to pyridoxic acid, (l→4) bond being formed.

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This investigation confirmed that undernourished infants and children who were in a state of mild-moderate protein-calorie malnutrition showed significant cognitive growth when their diet was supplemened with lysine-threonine tablets for more than 3 years. In children over 3 years of age a rise in D. Q. might be less pronounced as compared with the cases of children under 3 years of age. Thus it is suggested that nutritional improvement of children in undernourished areas may somehow influence mental development, while it is certain that social, and environmental factors have a very important influence on brain function.

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Addition of hydrocortisone to medium with a well-balanced amino acid composition, such as Eagle's Minimum Essential Medium, inhibited the growth of HeLa cells. However, hydrocortisone had various effects when added to cells cultured in media in which only one amino acid was reduced. Its effect depended on the deficient amino acid: in media of low isoleucine, methionine or phenylalanine content it pro-moted cell growth, while in media of low lysine or histidine content it had no effect.
In medium containing a low level of methionine (Low Met Med), the free methionine content in the cells increased on addition of hydrocortisone. The incorporation of ³⁵S-methionine into the acid-soluble fraction of these cells also increased on addition of hydrocortisone. Thus the growth promoting effect of hydrocortisone on cells cultured in Low Met Med may be dependent on increased absorption of limiting amino acid into cells.

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Pure linoleic acid hydroperoxides and their secondary degraded products have been used as radical and non-radical products of oxidized lipids to determine the mechanism of polymerization of proteins by oxidized lipids. The radical reaction effecting polymerization of proteins was found to be specific with proteins and the mechanism of polymerization involves the initiation of protein radical formation by hydroperoxides which in turn interacts to form polymers. The polymerization of proteins by the non-radical products may be attributed to the intermolecular carbonyl-amine cross-linking reaction.

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The effect of vitamin D on the metabolism of Ca and P has been studied in-tensively for many years, and is still under active investigation (1). There is the possibility, however, that it may affect, directly or indirectly, aspects of metabolism other than mineral. For example, since ergocalciferol is known to influence citrate metabolism (2) it may affect the metabolism of other substances such as fatty acids. It has been shown recently (3-5) in fact, that the administration of ergocalciferol to rachitic rats increases the uptake of ³²P-orthophosphate by the phospholipids of the intestinal mucosa, liver, and kidney, and that it increases the triglyceride content of bone (6). Although toxic doses of vitamin D do not influence the proportions of the various fatty acids in the livers of rachitic rats (7), it would be of interest to know whether nontoxic levels of vitamin D would influence fatty acid distribution in the triglycerides significantly, and thus perhaps indirectly influence the structure of the cell membranes in areas critical for Ca absorption (8).

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