Structure of Carbohydrate Moiety of Asterosaponin A

Partial acid hydrolysis of asterosaponin A, a steroidal saponin, afforded two new disaccharides in addition to O-(6-deoxy-α-d-glucopyranosyl)-(l→4)-6-deoxy-d-glucose which has been characterized in the preceding paper. The formers were demonstrated as O-(6-deoxy-α-d-galactopyranosyl)-(1→4)-6-deoxy-d-glucose and O-(6-deoxy-α-d-galactopyranosyl)-(l→4)-6-deoxy-d-galactose, respectively.

Accordingly, the structure of carbohydrate moiety being composed of two moles each of 6-deoxy-d-galactose and 6-deoxy-d-glucose, was established as O-(6-deoxy-α-d-galactopyranosyl)-(l→4)-O-(6-deoxy-α-d-galactopyranosyl)-(l→4)-O-(6-deoxy-α-d-glucopyranosyl)-(l→4)-6-deoxy-d-glucose, which is attached to the steroidal aglycone through an O-acetal glycosidic linkage.     

Studies on Oxygen Transfer in Submerged Fermentations

The unsteady-state gas analysis method for the determination of oxygen transfer rate in shaken cultures was applied to the glutamic acid fermentation. This method was essentially based on the measurement of oxygen tension of gas phase in flasks. Major intentions of this application were to clarify the problems of oxygen transfer, to establish the measure of aeration effectiveness and to design the best aeration condition in the glutamic acid fermentation. Correlations of the fermentation to the level of dissolved oxygen, the rate of oxygen transfer, overall oxygen transfer coefficient and oxygen demand of cells were examined. As a measure of aeration effectiveness, the rate of oxygen transfer actually occurring in the fermentation seemed to be preferable, and was found to be above 7 × 10^?7 mol/ml-min for attaining the maximum productivity. Extremely high or low oxygen supply resulted in less productivity.     

Isolation and Identification of Endogenous Cytokinins from Alfalfa (Medicago sativa L)

Endogenous cytokinins in alfalfa were isolated, and identified by mass spectrometry, trans- Ribosylzeatin (RZ) and ribosyldihydrozeatin (DHRZ) were identified from the root, and the combined content (benzyladenine equivalent) was estimated to be approximately 0.5/μg/100 g of fresh weight, eis- and trans-KL were identified from the stems and leaves. The relative content of the m-isomer was approximately five times greater than that of the trans-isomer.     

Properties of Nucleoside Phosphorylase from Enterobacter aerogenes

The properties of uridine Phosphorylase (UPase) and purine nucleoside Phosphorylase (PNPase) at high temperature were investigated. Both enzymes were found to be distributed in a wide range of bacteria and were partially purified from Enterobacter aerogenes AJ 11125 by heat treatment, ammonium sulfate fractionation and column chromatographies onDEAE-cellulose and Sephadex G-150. The UPase was purified 109-fold, and it showed an optimum pH of 8.5 and optimum temperature of 65°C, and activity toward uridine, 2′-deoxyuridine, thymidine and uracil arabinoside but not cytidine. The Km values of UPase for uridine were 0.7 mm at 40°C and 1.8 mm at 60°C. The PNPase was purified 83-fold, and it showed an optimum pH of 6.8 and optimum temperature of 60°C, and significant activity toward purine arabinosides as well as purine ribosides. The Km values of PNPase for inosine were 0.8 mm at 40°C and 2.2 mm at 60°C.     

Studies on the Monoterpene Fraction of “Geranium Oil” from Pelargonium roseum Bourbon

Investigation has been carried out on the constituents of the monoterpene fraction of geranium oil from Pelargonium roseum Bourbon and, besides well-known components of the oil, some new components such as epoxylinalool, methyl heptenone, myrcene, limonene, p-cymene, citral and 2,2,6-trimethyl-6-vinyl-tetrahydropyran which was confirmed by deriving to cinenic acid, have been identified.     

Basic Aspects of Electrode Potential Change in Submerged Fermentation

The platinum electrode potentials relative to the standard half cell depended on a pH value, dissolved oxygen concentration, equilibrium constant and oxidation reduction potentials of the liquid The overall potential change in submerged fermentation gave no independent information on these individual factors A thermostatic and pH-static apparatus excluded influences of temperatures and pH values on the electrode pontentials If the determination was completed for short time duration, potentials were governed by the dissolved oxygen tension. While the oxygen concentration was maintained at a same level, redox potential changes became a dominant. This measurement of redox potential, which gave the concentration of extremely low dissolved oxygen that could not be detected by the membrane-coated oxygen electrode, was practically useful for the control of aerobic fermentation     

Conversions of Microbial Products in Relation to Oxygen Supply in Inosine Fermentation

On the basis of the ratio (cell’s respiration rate/maximum oxygen demand of cells, r_{a b}/K_rM) as a new criterion of oxygen supply, symptoms of oxygen deficiency was described in inosine fermentation. Conversions of the products were observed to occur in relation to the extent of oxygen deficiency. When oxygen demand of the cells was satisfied (r_{a b}/K_rM = 1.0), the cells accumulated exclusively inosine. Under limited oxygen supply at the value of r_{a b}/K_rM 0.5~0.9, on the other hand, inosine formation was inhibited and acetoin was the predominant product. When oxygen supply was limited more strictly at the value of r_{a b}/K_rM smaller than 0.3, the cells excreted 2,3-butyleneglycol as the main product.