Isolation and Identification of a Novel β-Carboline Derivative in Salted Radish Roots,Raphanus sativus L.

The methanol extract of salted radish roots contains several precursors of yellow pigment. The main compound was isolated by the use of Toyopearl HW-40S column chromatography, and its structure was determined to be 1-(2′-pyrrolidinethion-3′-yl)-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid on the basis of an elemental analysis, and IR, UV, FAB-MS and NMR spectroscopy. This compound is presumed to have been the condensation product from the degradation of 4-methylthio-3-butenyl isothiocyanate and l-tryptophan. This carboline compound is considered to play an important role in the formation of the yellow pigment in salted radish roots.     

Purification and Properties of meso-α,∊-Diaminopimelate Decarboxylase from Bacillus sphaericus

Soybean 7S and 11S globulins were stored at relative humidities (RHs) of 11% and 96% at 50°C. The redispersibility of the proteins at RH 96% decreased in a short time. However, it did not decrease, when stored for 45 days at RH 11%. Gel filtration showed that the proteins polymerized during storage. The effects of urea, sodium dodecyl sulfate (SDS) and 2-mercaptoethanol (2-ME) on the redispersibilities of the proteins at RH 96% showed that the hydrogen, hydrophobic and disulfide bonds participate in the polymerization of 7S globulin, and that the disulfide bond is strongly related to the polymerization of 11S globulin. Redispersibility was restored with 2-ME in both the 7S and 11S globulins and some of the proteins in the supernatant redispersed with 2-ME were observed to be similar to the native ones with respect to the gel filtration, electrophoretic behavior and circular dichroism spectrum.     

Some Properties of an Invertase-liberating Enzyme Isolated from Zymolyase

An enzyme which released invertase from cell ghosts of Candida utilis was isolated in an electrophoretically pure state from “Zymolyase.” The molecular weight of the purified enzyme was estimated to be 5.8 × 10⁴, and its isoelectric point was pH 6.9. The enzyme was stable in a pH range from 6.0 to 9.0, and the optimal pH for liberation of invertase from cell ghosts was around 6.0. The activity of the enzyme was competitively inhibited by glucose, mannose, and sucrose. Unlike the starting enzyme preparation, “Zymolyase,” the purified enzyme released invertase without making holes on the surface of the cell ghosts. Various tests were applied, but the specificity of the enzyme was not defined.     

Excretion of 5′-Nucleotides from Bacterial Cells

Incubating the dried cells of Brevibacterium sojae No. 425-40 in alkaline buffer, the excretion of 5′-nucleotides accompanying with the decrease of intracellular RNA was observed. Then the determination of the optimum condition of the excretion and the investigation on the enzyme responsible for the degradation of endogenous RNA were carried out.

In the experiments using sonicate and disrupted cells, it appeared that orthophos-phate and Mg⁺⁺ might be accelerative or essential for the degradation of endogenous RNA and, in addition to four 5′-nucleotides (AMP, GMP, UMP and CMP), each nucleoside 5′-diphosphate was also contained in its degraded products. Nucleoside 2′- or 3′-monophos-phates were not detected. Although it was not clear whether phosphodiesterase concerned with the degradation of intracellular RNA or not, it was suggested that polynucleotide phos-phorylase acted mainly on the degradation.

The maximal excretion of 5′-nucleotides from dried cells was obtained by suspending 1 to 2% of dried cells in 0.05 M carbonate-bicarbonate buffer (pH 10) and incubating it at 60°C for two to three hours. Orthophosphate and Mg⁺⁺ were not required for the excretion.     

Structure of Trigalactosyldiglyceride Isolated from Alfalfa Leaves

Theoretical and experimental investigations were conducted on growth kinetics and substrate consumption of hydrogen bacterium Alcaligenes hydrogenophilus. The kinetic models proposed were evaluated by continuous cultures of A. hydrogenophilus under various conditions. The kinetic models closely simulated continuous cultures of A. hydrogenophilus.     

Production of Lysine by Pyruvate Dehydrogenase Mutants of Brevibacterium flavum

Mutants with low pyruvate dehydrogenase (PD) activities were derived from a pyruvate kinase-deficient lysine-producing mutant of Brevibacterium flavum, No. 22. They were selected as prototrophic revertants of the acetate auxotrophs of strain No. 22. Among them strain KD-11 produced 55g/liter of lysine as its HCI salt when cultured for 72 hr in a medium containing lOOg/liter of glucose, soybean-meal hydrolysate and methionine. The lysine yield of strain KD-11 was the highest ever reported (55%). The mutant required a higher concentration of methionine for maximum production and gave a smaller amount of cell mass in cultivation than its parent. PD activity of strain No. 22 was stimulated by cysteine, stabilized by glycerol, and gave apparent Kms of 89, 22, 380, 83 μM for pyruvate, coenzyme A, 3-acetylpyridine adenine dinucleotide, and NAD, respectively, under standard conditions. The apparent Km for NAD of PD from strain KD-11 was 10-times higher than that from No. 22. When the concentration of NAD was low, the cell extracts of strain KD-11 showed low PD activity. The specific activity of phosphoenolpyruvate carboxylase of strain KD-11 was slightly higher than that of strain No. 22, while the inhibition by aspartate of the former enzyme was weaker than that of the latter.     

Isolation of Cerebroside from Pea Seeds

Cerebroside was isolated from pea (Pisum sativum L.) seeds by solvent extraction, mild alkaline hydrolysis and silicic acid column chromatography. The purified material was identified as cerebroside by thin-layer chromatography and infrared spectrometry. Hydrolysates of the cerebroside were divided into fatty acid, sphingosine base and sugar fractions, and analysed, mainly by gas-liquid chromatography. The major fatty acid components were hydroxytricosanoic, hydroxydocosanoic and hydroxytetracosanoic acids. Dihydrosphingosine was the predominant sphingosine base. Only glucose was detected in the sugar fraction. Based on these results, one of the major species of pea cerebroside is suggested to be N-hydroxytricosanoyl-glucopyranosyl-dihydrosphingosine.     

Enzymatic Formation of Hexadecenoic Acid from Palmitic Acid

Desaturation of palmitic acid was investigated in an enzyme system prepared from rat liver. 2-trans-Hexadecenoic acid as well as 9-cis-hexadecenoic acid (palmitoleic acid) were found to be formed as monoenoic acid in this system.     

Ceramide in Rice Grain

A rice lamina inclination test that is simple and specific for brassinosteroids was used as a micro-quantitative bioassay for brassinolide 1 and its 6-keto congener, castasterone 2, in the concentration range of 5 x 10^–5 /ig/ml to 5 x 10^–3μg/ml, when uniform seedlings of the rice cultivars Arborio J-l and Nihonbare were selected. A phytohormone, indole-3-acetic acid (IAA), showed similar activity in this bioassay. Its lowest effective concentration, however, was 50 /ig/μl, about five orders of magnitude greater than that of brassinolide. Other phytohormones, abscisic acid (ABA) and the cytokinins kinetin and A⁶-benzyladenine, inhibited the lamina inclination of rice seedlings. The addition of a cytokinin reduced the promoting effect of brassinolide. Thus, the rice lamina inclination test can be used both as a micro-quantitative bioassay for brassinosteroids and as a method for detecting antibrassinolide compouds.     

Absorption,Translocation and Metabolism of O,O-Diisopropyl S-Benzyl Phosphorothiolate (Kitazin P®) in Rice Plant

Behavior and metabolism of O,O-diisopropyl S-benzyl phosphorothiolate (Kitazin P©) in rice plant were examined using ³²P, ³⁵S-double labeled compound. Uptake of Kitazin P by the plant was different with the growth stages of the plant, and the rate of uptake was rapid in early growth stage. Kitazin P penetrated into plant tissues was gradually hydrolyzed to produce O,O-diisopropyl hydrogen phosphorothioate which was converted to diisopropyl hydrogen phosphate, isopropyl dihydrogen phosphate and phosphoric acid. As toluene soluble metabolites, eight spots were detected by thin-layer chromatography, but their percentages in toluene soluble fraction were extremely low as compared with that of Kitazin P. Only two metabolites, dibenzyl disulfide and O,O-diisopropyl O-benzyl phosphorothionate were identified by a gas-liquid chromatography with a flame thermionic detector or a flame photometric detector. Diisopropyl hydrogen phosphorothioate was detected as a persistent metabolite even in rice grains.