Since 1950 we have conducted a series of experiments on the diabetic symptoms in albino rats caused by the administration of xanthurenic acid (XA), an abnormal metabolite of tryptophan. Our studies have given conclusive evidence that XA is related to the development of human diabetes, a disease generally attributes to an inadequate food intake. Evidence also suggests that there is a close relationship between animal and human diabetes.
Experiments have shown that XA is a substance produced in the body as a result of intake of excess of the sodium salts of fatty acid (representing fat) and tryptophan (representing animal protein).
Taking into consideration the chronic nature of human diabetes, we then studied the development of chronic diabetic symptoms in rat caused by accumulative effect of XA produced in the body when vitamin B₆ deficient diet or excessive fat and tryptophan diet was administered for a long period. Then the pancreatic tissue of these rats was examined histologically. A decrease of stainability, a decrease in granules, much vacuole formation, and collapse of the protoplasm were noticeable in the β-cells of the islets of Langerhans.
We then examined fairly large amount of XA in the urine of many diabetic patients by the partition paper chromatographic method. These is an undeniable etiological relationship between free XA and human diabetes since a fairly large amount of XA in a free form present in the urine was invariably present in the urines of diabetic patients.
Murakami, one of our co-worker, recently showed that XA formed a binding complex with insulin. We have observed XA bound with insulin in human serum. XA-insulin complex showed a new fruorescence spectrum. The hormonal activity of XA-insulin complex was markedly decreased.
From these results we may suggest that experimental diabetes in the presence of XA may be induced by the following mechanism:

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The nutritional experiments have been made with the use of proteins partially hydrolyzed with protease derived from mold.
1) The rats given enzyme-treated egg protein or soy-protein showed better growth than those given untreated one.
2) The rats given the enzyme-treated casein showed rather slower growth rate than those given untreated one. This tendency was particularly obvious with enzyme-treated gluten.

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The nutritional experiments have been made with the use of partially hydrolyzed products of casein with acid or alkaline proteases.
1) The rats given acid protease-treated casein showed slower growth rate than those given untreated one. On the contrary, it showed better growth in the case of alkaline protease.
2) From the quantitative analyses on the free amino acids, it was shown that casein partially hydrolyzed with alkaline protease contained more essential amino acids such as tryptophan, lysine, arginine, methionine etc. than acid protease treated casein and amino acid composition of untreated casein.

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The effect of the fasting on their adipose tissue weights, lipid contents of adipose tissues, and the fatty acid compositions of epididymal and perirenal fat pad lipids were studied in rats. When male rats of approximately 380g body weight were subjected for fasting of one week, their body weights decreased about 65g.
The tissue weight of subcutaneous and perirenal adipose tissues decreased after one-week fasting significantly, followed by the decrease of epididymal fat pad. The decrease of mesenteric, omental, and interscapular fat tissues, however, was much less compared with this of the former three tissues. Lipid contents of six adipose tissues mentioned above were decreased significantly, especially in subcutaneous and perirenal adipose tissues, but in the epididymal adipose tissue the decrease was not remarkable in comparison to the formers. The mesenteric, omental, and interscapular adipose tissues showed only slight decreases.
In epididymal adipose tissue, the loss of the weight of tissue after one-week fasting was 1.0g in average, whereas the decrease of lipid was 1.4g. The discrepancy of the figures may reveal the increase of the other tissue components than lipid. Such tendency was not observed in the other adipose tissues.
The fatty acid composition of epididymal fat tissue was not changed by fasting, but the percentage of oleic acid increased significantly in perirenal fat tissue whose tissue weight and lipid content were decreased much more than the epididymal fat tissue.
From the data obtained in the present study it is suggested that the each adipose tissue in fasting animals has different lipid metabolism.
Adipose tissue metabolism in vitro and in vivo has been compared.

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Atomic absorption spectrophotometry was applied to the determination of iron in foods.
(1) Absorbancy at 248.3mμ was meassured to determine iron.
(2) A linear relationship between an absorbancy and a concentration was found within the range of 0-15 ppm iron.
(3) Samples were burnt to ashes in an electric muffle furnace at 550°C, and after the ashes were dissolved with 4ml. of 6 N hydrochloric acid and made up to 100ml. with water, the solution was submitted to the analysis of iron.
(4) Silicon, aluminum, phosphate, tin, zinc and chromium interfered with the determination of iron remarkably and other metals interfered only slightly, but the interferences were eliminated by adding excess amount of strontium.
(5) Recoveries of iron added were satisfactory, and the values obtained by atomic absorption spectrophotometry agreed well with those obtained by o-Phenanthroline method.
(6) The reproducibility of analytical values was satisfactory, that is, the coefficient of variation for iron was 1.63% for skipjack and 4.23% for clam.
(7) Contents of iron in marine products were about 1-20mg%, and the content of it in shrimp was the smallest of all marine products examined, and contents of it in clams were remarkably high in comparison with other fishes.
Since the determination of iron by atomic absorption spectrophotometry is convenient and rapid, and the interferences of coexistent elements can be controlled by a mere addition of strontium, it is considered that this method is the best for the determination of iron in foods.

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The present paper deals with the activity of succinic dehydrogenase of various fishes.
The activity of succinic dehydrogenase of various fishes was estimated by the colorimetric method using 2, 3, 5-riphenyltetrazolium chloride.
The results obtained were as follows:
(1) The reaction rate of succinic dehydrogenase of Venerupis japonica “Asari” and Anadara broughtonii “Akagai” was slower than that of other fishes.
(2) The activity of succinic dehydrogenase of Venerupis japonica “Asari” and Anadara broughtonii “Akagai” was almost similar to that of other fishes with the exception of Hexagrammos otakii “Ainame” Ammodytes personatus “Ikanago”, Penaeus japonicus “Kurumaebi”, Sepia esculenta “Kouika” and Octopus fangsiao “Iidako”.
(3) This activity of Penaeus japonicus “Kurumaebi” was the highest among various fishes examined, being about 10 times as high as that of clams.
(4) This activity of Octopus fangsiao “Iidako”, Sepia esculenta “Kouika” and Hexagrammos otakii “Ainame” was about 3-4 times as high as that of clams.

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The present investigation was undertaken to see changes of free sugar contents in sarcocarp and seed during the ripening period of pumpkin, balsam apple, sweet pepper and trifoliata orange. Free sugar contents in sarcocarp and seed of various ripening stages were determined by the use of the cutting method of paper chromatograms and micro-BERTRAND method and, more over, the fractional quantitative analysis of these free sugars were studied. During the ripening period of these seeds, glucose and sucrose still continued to exist, while raffinose and stachyose appeared in the later stage of ripening period. The contents of glucose in sarcocarp and seed were in the highest degree of all the sugars throughout the all ripening process. The contents of glucose in sarcocarp of pumpkin, sweet pepper and trifoliata orange gave minimum values at the unripe stage of sarcocarp and gave maximum value at the later stage of ripeness.

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Aseptic rearing has been receiving much attention in recent years. Since silkworm larvae grow very fast and uniformly, they are suitable for aseptic rearing. The authors have attempted nutritional and pathological studies using aseptic rearing silkworm. The present paper deals with an artificial food of silkworm larvae for this purpose.
The artificial food prepared was composed of fat-free rice bran, powdered mulberry leaves, potato starch, sucrose, agar-agar, vitamins and some feeding stimulants.
Silkworm larvae ate little fat-free rice bran, but ate it when it had been treated with 1.5% sulfuric acid or methanol. Silkworm larvae were well grown from eggs to moths with the artificial food, and the results of these rearing showed that fat-free rice bran can be used as an artificial food of the silkworm larvne.

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Protein score (FAO score, FAO 1955) was compared with chemical score (egg score and human milk score, FAO/WHO 1963) and E/T ratio in hospital diet for children.
1) Diet protein value judged from “common sence” was better correlated with FAO score than egg score or human milk score.
2) It is not so easy to evaluate protein using chemical score and E/T ratio as mono-dimentional value. As a simple method for protein evaluation, it may be convenient to use mono-dimentional scoring system.
3) To evaluate diet for infants and young children which contain milk and its products, use of the human milk score may be more suitable than the egg score.
4) The limiting amino acid of the egg score is tryptophan and that of the human milk score is usually S-containing amino acid. It may be more rational to use an intermediate pattern as a reference protein.

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Having verified the presence of trypsin inhibiting substances in purple laver, the study was made on their properties and thd following results were obtained.
1. The extracted volume of inhibitors increased in proportion to the concentration of sodium chloride. Extraction was optimal near the neutrality. 2. The substances showed no inhibiting effect on pepsin but contrarily they were digested by pepsin and their inhibiting effect was reduced by about 50%. They were mostly precipitated at 0.8 saturation of ammonium sulphate and of aceton. 3. The inhibiting substances were separated into two patterns by means of DEAE-cellulose column chromatography. 4. Stability in heat resistance was quite high in some substances but not so high in some others.

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In a study of the physical and chemical properties of rice, the effects of the various temperatures on the pH values, reducing sugar content, water-soluble dry matter content, enzymatic activities of brown rice and respiration rate of unhulled rice were determined during continuous drying of fresh unhulled rice.
The higher the temperature of drying, the smaller were the pH values, and the amounts of watersoluble dry matter content of brown rice. Another practical significance was the gradual loss in reducing sugar, which affects taste, at high temperatures such as 50°C, 60°C and 70°C. The maximum content of reducing sugar of rice was recognized at 30°C or 40°C. These were accompanied by changes in alpha- and beta- amylase activities.
Residual catalase and peroxidase activities were also decreased at high temperatures. Respiration rate of unhulled rice was high at 60°C.
From the data now obtained, it was assumed that optimum temperatures of drying rice would be 30°-40°C in practice.

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Effects of the length of the drying time of unhulled rice on physical and chemical properties of brown rice were investigated. The longer the drying time of unhulled rice, the smaller were the pH values, the amounts of water-soluble dry matter, residual catalase and peroxidase activities. The amounts of reducing sugar also decreased with the duration of beating.
In addition, it appeared that intermittent heating process for dehydration of unhulled rice was a a better method to prevent the thermal deterioration of the physical and chemical qualities of rice than continuous drying.

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Decrease of electric conductivity of brown rice was noted when fresh unhulled rice was dried to 14% of moisture at high temperatures (70°C, 60°C, 50°C). In contrast, brown rice prepared by unartificial drying showed high figures of electric conductivity. In addition, the longer the time of drying of unhulled rice, the lower was the electric conductivity of brown rice.
It was apparent from the evidence at hand that this decrease of electric conductivity by heating of unhulled rice was due to the decrease of solubility of potassium in rice.

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