Relation between Fatty Acid Composition of Cellular Phospholipids and the Excretion of L-Glutamic Acid by a Glycerol Auxotroph of Corynebacterium alkanolyticum

Relation between fatty acid composition of cellular phospholipids and the excretion of L-glutamic acid was investigated using Corynebacterium alkanolyticum GL–21 (a glycerol auxotroph).

When grown on n-hexadecane, the proportion of unsaturated fatty acids was higher in L-glutamic acid-accumulating cells than in L-glutamic acid-nonaccumulating cells. When grown on fructose or acetic acid, the reverse relation was observed. Moreover, cells containing no oleic acid produced L-glutamic acid from n-pentadecane.

These results suggest that the membrane permeability to L-glutamic acid is not always controlled by the cellular content of unsaturated fatty acids.     

Colorimetric Determination of 2-Chlorophenyl N-Methylcarbamate

2-Chlorophenyl N-methylcarbamate was determined colorimetrically. It was hydrolyzed with a veronal buffer solution (pH 8.0) to give corresponding 2-chlorophenol, which was coupled 4-nitrobenzenediazonium fluoroborate to produce a color having a maximum absorption at 520 mμ. The developed color was very stable. On the other hand, contaminated 2-chlorophenol was adsorbed in treated alumina before being hydrolyzed. Other contaminated impurities gave little influences. Technical materials and some formulated products were determined and good results were obtained.     

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.     

On the Modes of Action of Three Xylanases Produced by a Strain of Aspergillus niger van Tieghem

The modes of action of three xylanases (I, II and III) produced by Aspergillus niger van Tieghem on several substrates were investigated. Xylanase I possesed the strongest activity against xylooligosaccharides among the three enzymes and converted them into xylose and xylobiose. Xylanase II and III catalyzed a glycosylating reaction and produced higher polymerized xylooligosaccharides from xylotetraose or xylopentaose. Among three enzymes, xylanase II could split α1,3-arabinofuranosidic bond of arabinose-xylose mixed oligosaccharides.

In the case of hydrolysis by three xylanases on xylan and arabinoxylan, the maximum hydrolysis degree and the reaction products were compared with each other. From the results, some speculation were made concerning the modes of action of the enzymes.     

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     

Purification and Properties of Lytic Enzymes from Streptomyces globisporus 1829

Two lytic enzymes capable of lysing Streptococcus mutans have been purified to give a single band on disc-gel electrophoresis, respectively. The M–1 and M–2 enzymes were both proved to be N-acetylmuramidases. However, these enzymes were entirely different on their enzymatic properties. The molecular weights were about 20,000 and 11,000 for M–1 and M–2 enzymes, respectively, The maximal lytic activity of M–1 enzyme was obtained at ionic strength 0.05, while lytic activity of M–2 enzyme did not change within the ionic strength range of 0 to 0.05. The M–1 enzyme constituted the majority of the total lytic activity against the cell walls of Streptococcus mutans BHT of cultured filtrate. The M–2 enzyme showed less specific lytic activity on the cell walls of Streptococcus mutans BHT than M–1 enzyme.     

The Purification and the Properties of Three Kinds of Lipases from Rhizopus delemer

The study was undertaken to clarify whether three kinds of lipases (EC 3.1.1.3) secreted from Rhizopus delemar are originally different or identical with each other. First of all, the purification of those lipases was carried out and their enzymatic properties were examined. Their properties including the stability on heat and pH, precipitabilities at a certain pH, the behaviours on a SE-Sephadex C50 column and on a Sephadex G200 column and so on were compared.

From the results, A-lipase is clearly different from the other two lipases. On the other hand, it seems that B- and C-lipases are originally identical.     

l-Acylimidazoles with Broad-spectrum Fungicidal Activity

The membrane lipids of six higher plants that differ in salt tolerance were analyzed and compared. The root lipids increased in a ratio of glycolipid/phospholipid with increasing salt- tolerance. A similar increase in the ratio was observed with increasing external salinity when halophytic orach and salt-sensitive cucumber were exposed to varying salinity, although the latter plant was limited to only a little increase. Measurements of ion-transport rates with artificial lipid membranes revealed that the root lipids from a salt-resistant plant formed a more permeable membrane than those from a salt-sensitive species. It was found that the membrane permeability was related to the glycolipid/phospholipid ratio in the membrane lipids, where the glycolipids were stimulative and the phospholipids were repressive for ion-flow. These different effects of the two lipid classes may be attributed to their molecular species and head groups.     

Extracellular Accumulation of Phospholipids,UDP-N-Acetylhexosamine Derivatives and L-Glutamic Acid by Penicillin-treated Corynebacterium alkanolyticum

The addition of penicillin to cells of Corynebacterium alkanolyticum No. 314 growing on n-paraffins medium caused the simultaneous excretion of phospholipids, UDP-N-acetylhexosamine derivatives and L-glutamic acid.

Among many antibiotics which inhibit cell wall synthesis, only the inhibitors of peptideglycan transpeptidase such as penicillin G and cephaloridine were effective for inducing the excretion of phospholipids, UDP-N-acetylhexosamine derivatives and L-glutamic acid, while the others promoted only the excretion of UDP-N-acetylhexosamine derivatives.

From the close relationship between the excretion of L-glutamic acid and the excretion of phospholipids, it was suggested that the action of penicillins and cephalosporins on the cell membrane resulted in the excretion of L-glutamic acid.