Transformation of Terpenoids in Grape Must by Botrytis cinerea

Experiments were done to investigate the volatile components in botrytized grape must and transformation of terpenoids in terpene-supplemented grape must by Botrytis cinerea. Twenty-eight compounds were identified in the volatile concentrate of botrytized must with a combined gas chromatograph-mass spectrometer. No terpenoids were detected in the concentrate. Linalool or terpinen-4-ol decreased a lot when Botrytis cinerea was cultured in the must with these terpenes for 15 days. In linalool-supplemented botrytized must 9 identified and 3 unidentified terpenes were found, while only geranial was detected in terpinen-4-ol-supplemented botrytized must. Botrytis cinerea did not produce terpenoid in grape must without terpenes, but transformed linalool added to grape must into some other monoterpenes.     

Isolation of Intact Chloroplasts from Spinach Leaf by Centrifugation in Gradients of the Modified Silica “Percoll”

The isolation of the photosynthetically competent chloroplast preparations was undertaken by means of the density gradient centrifugation on the modified silica sol “Percoll.” A clear separation of the intact chloroplast sustaining the high photosynthetic activities (light dependent CO₂ fixation ca. 130μmol/mg Chl·hr) was established. The contamination of mitochondria and peroxisomes was estimated to be less than 3% by measuring the activities of their marker enzymes. The chloroplasts were proved to be free from endoplasmic reticulum and cytosol. The photosynthetic CO₂ fixation of the isolated chloroplast preparations was saturated by illumination of the light intensity of 20,000 Lux (12 mW/cm², 400~750 nm).     

Role of O-Methyltransferase in the Lignification of Bamboo

Characterization of S-adenosylmethionine: catechol O-methyltransferase (EC. 2. 1. 1.6) isolated from bamboo shoot was carried out. Ferulic and sinapic acids which are believed to be lignin precursors are formed by the mediation of the enzyme, and the enzyme activity increased progressively during the lignification of bamboo shoots. Evidences suggest that this enzyme may contribute to the synthesis of lignin precursors.     

A Diphosphopyridine Nucleotide Oxidase in Mung Bean Seedlings

Although the electrolytically obtained DPNH was not completely oxidized by usual dehydrogenases or diaphorases, one of the authors noticed that its absorption band at 340 mμ disappeared completely when it was incubated with the extract of mung been seedlings. The reaction was found to be stimulated by the addition of methylene blue, and the product was identified as DPN. Thus, the reaction resembled that of diaphorase, although it was less specific to the configuration of DPNH. But unlike usual diaphorase, it required a cofactor, which was neither flavins nor metallic ion, but an unidentified acidic substance. General properties of the enzyme and the cofactor are reported in this article.     

Preparation of Mutants Resistant to Catabolite Repression of Trichoderma reesei

The development of agar plate screening techniques has allowed the isolation of mutants of Trichoderma reesei capable of synthesizing cellulase under the conditions of a high concentration of glucose. Mutants resistant to catabolite repression by glycerol or glucose were isolated on Walseth’s cellulose (WC) agar plates containing 5% glycerol or 5% glucose, respectively. Mutants resistant to catabolite repression by glycerol were not derepressed enough for the production of cellulase on WC agar plates containing 5% glucose or in flask cultures with a mixture of 1% Avicel and 3% glucose. On the contrary, two mutant strains resistant to catabolite repression by glucose (KDD-10 and DGD-16) produced large clearing zones on WC agar plates containing 5% glucose. Both strains could begin to produce CMCase even in the presence of residual glucose and finally produced 1.5 times the CMCase activity, in flask cultures on 1% Avicel and 3% glucose, than that with 1% Avicel alone. These results suggest that KDD-10 and DGD-16 are comparatively derepressed by glucose for cellulase production.     

Purification and Properties of Penicillin Acylase from Kluyvera citrophila

Penicillin acylase (EC 3.5.1.11) of Kluyvera citrophila KY7844 was purified approximately 120-fold by DEAE-cellulose chromatography, hydroxyapatite chromatography and isoelectro-focusing fractionation. The purified enzyme, with an approximate molecular weight of 63,000, appeared to be homogeneous in disc electrophoretic analysis, and showed isoelectric point (Ip) 8.12 and 13.0 units/mg of specific activity for cephalexin hydrolysis. The Michaelis constant (Km) for cephalexin and for 7-[1-(1H)-tetrazolylacetamido]-desacetoxycephalosporanic acid ((1H) T-7ADCA) was 1.4 mM and 3.6 mM, respectively. This enzyme was capable of producing (1H) T-7ADCA in 80% yield from 1-(1H)-tetrazolylacetate methylester and 7-aminodesacetoxycephalosporanic acid.     

Fermentation of C14-Labeled Cellobiose by Cellulomonas fimi

Crude cell-free extracts from Cellulomonas fimi contain cellobiose phosphorylase which cleaves cellobiose into glucose and glucose-1-phosphate in the presence of inorganic phosphate. With the aid of this enzyme, two samples of C¹⁴-cellobiose labeled in reducing or non-reducing glucosyl moiety were prepared from uniformly labeled C¹⁴-glucose or C¹⁴-glucose-1-phosphate as substrate, respectively. The labeled preparations have been shown to be radiochemically pure. Analyses of the anaerobic fermentation products from C¹⁴-cellobiose by resting cell suspensions showed that both glucose moieties were fermented almost equivalently. However, relatively small differences in specific activities of the products revealed that significantly larger amounts of formic acid and smaller amounts of acetic acid were produced from the reducing glucose moiety than from the other half of the molecule. Succinic and lactic acids appeared to be produced almost equally from both moieties.     

Development of preparative and analytical methods of the hop bitter acid oxide fraction and chemical properties of its components

The bitter acids in hops (Humulus lupulus L.) and beer, such as α-, β-, and iso-α-acids, are known to affect beer quality and display various physiological effects. However, these compounds readily oxidize, and the effect of the oxides on the properties of beer or their potential health benefits are not well understood. In this study, we developed a simple preparative method for the bitter acid oxide fraction derived from hops and designated the constituents as matured hop bitter acids (MHBA). HPLC-PDA-ESI/HRMS and MS² revealed that MHBA are primarily composed of α-acid-derived oxides, which possess a common β-tricarbonyl moiety in their structures similar to α-, β-, and iso-α-acids. We also developed a quantitative analytical method of whole MHBA by HPLC, which showed high precision and reproducibility. Using our newly developed method, the concentration of whole MHBA in several commercial beers was evaluated. Our results will promote the study of bitter acid oxides.     

Re-evaluation of physical interaction between plant peroxisomes and other organelles using live-cell imaging techniques

The dynamic behavior of organelles is essential for plant survival under various environmental conditions. Plant organelles, with various functions,migrate along actin filaments and contact other types of organelles, leading to physical interactions at a specific site called the membrane contact site. Recent studies have revealed the importance of physical interactions in maintaining efficient metabolite flow between organelles.In this review, we first summarize peroxisome function under different environmental conditions and growth stages to understand organelle interactions. We then discuss current knowledge regarding the interactions between peroxisome and other organelles, i.e., the oil bodies, chloroplast, and mitochondria from the perspective of metabolic and physiological regulation, with reference to various organelle interactions and techniques for estimating organelle interactions occurring in plant cells.