Intermediate Energy Metabolism of Leptospira

Metabolic studies were performed on three representative serotypes of Leptospira: a water isolate designated B(16) and two pathogenic serotypes, pomona and schueffneri. Examination of whole cells of B(16) for their ability to oxidize various substrates revealed that oleate significantly stimulated oxygen uptake. The respiratory quotient of 0.7 implied that oleate was degraded to carbon dioxide and water. Other substrates, such as carbohydrates, alcohols, intermediates of the citric acid cycle, and short-chain acids, including selected amino acids, did not stimulate endogenous respiration of whole cells. No oxygen uptake could be measured when cell-free extracts were tested with the substrates used with whole cells. Enzymatic analyses of cell-free extracts of the three strains demonstrated enzymes of the citric acid cycle, enzymes of the glycolytic and pentose pathways, and the general acyl coenzyme A dehydrogenase required for beta-oxidation of fatty acids. Strain B(16) and the two pathogenic serotypes appeared to possess similar metabolic capabilities. Enzymatic data might also explain the apparent inability of B(16) to oxidize other substrates; kinases necessary for activation of common nonphosphorylated compounds were not detected in leptospiral extracts. These findings emphasized the dependence of leptospiral growth upon long-chain fatty acids.     

Studies on the Metabolism of Aspergillii

Endogenous respiration of Aspergillus sojae K.S. was studied in terms of biochemical analysis. It was found that the different kind of substrates was utilized for the endogenous respiratoin according to C:N ratio of the agar medium on which the mold was grown. In the mycelial mats grown on the medium of low C:N value, pool amino acids, protein, and nucleic acids were mainly utilized from the beginning while carbohydrate or lipid displayed a minor role. The corresponding amount of ammonia was formed. On the other hand, in the mycelial mats grown on the medium of rather high C:N value, carbohydrate or lipid was the major substrate of endogenous respiration in the early stages of incubation. The utilization of the nitrogenous materials and the accompanying formation of ammonia got to start only after the lapse of several hours of incubation.     

Studies on the Metabolism of Aspergilli

It was found that either γ-glutamic hydrazide or hydrazine at an appropriate concentration stimulated the formation of glutamic dehydrogenase as well as transaminases. Addition of l-glutamine partially reduced the stimulating effects of analogues.     

Studies on the Metabolism of Aspergilli

Studies were made on the endogenous respiration of Aspergillus sojae K.S. Observing the changes of Kjeldahl-nitrogen in each fraction of the mycelial components, the author concluded that pool amino acids, bound amino acids, protein, nucleic acids and nucleotides covered whole of the nitrogenous reserves available for endogenous respiration in the mycelia. A study was carried out on the effect of preincubation with glucose or amino acids on endogenous respiration. Stimulation of either oxygen uptake, protein breakdown or ammonia formation was observed during respiration of the mycelia incubated with a suitable concentration of azide, 2,4-dinitrophenol, potossium fluoride, monoiodoacetic acid or ethylenediaminetetraacetic acid. Ammonia formation accompanied with endogenous respiration seemed to proceed inversely by the influence of energy yielding reaction.     

Studies on the Metabolism of Aspergilli

Studies were made on the effect of water level of culture medium on the mycelial compositions and enzyme production in Aspergillus sojae K. S. The mold was grown on the media of various water levels made of powder of defatted soybean and wheat granule. The mycelia grown on the medium of low water level produced more protease and α-amylase, consumed more oxygen, formed less ammonia, and were richer in 2 n H₂SO₄-soluble glycogen, 60% H₂SO₄-soluble carbohydrates, protein and RNA per mg dry weight than the mycelia grown on the medium of high water level. Chromatographic analyses were carried out for nucleotides, sugar phosphates and free carbohydrates in cold TCA-soluble fraction of the mycelia.     

Studies on the Metabolism of Aspergilli

This report is concerned with the time course of changes of several enzymes during endogenous respiration. It was observed that enzymes such as deaminases, amidases and transaminases found in the mycelia increased in activity more or less during endogenous respiration. It was assumed that enzyme formation occurred as the result of glucose starvation or depression of carbohydrate metabolism during endogenous respiration of the mold mycelia on buffer solution.     

钩端螺旋体内毒素的研究：Ⅴ,乙二胺四乙酸二钠对钩端螺旋体...

The yield of leptospiral LPS was able to increase 1-2 times when the cells were treated with EDTA-Na before extracting with hot phenal-water method. The colours and solubility of L-LPS were improved. When the leptospiral cells were stored for a long period of time, and treated by EDTA-Na, the phase distribution of the LPS changed, i.e. they returned from water phase into phenol phase. Such change was related to the quantity of both the saccharide and lipid.     

Studies on the Nitrogen Metabolism in Ectomycorrhizae

Concentrations of free and bound amino acids were determined in 1) the mycorrhizal fungus Boletus variegatus Fr. 2) nonmycorrhizal root systems of aseptically grown Pinus sylvestris L. seedlings, and 3) mycorrhizal root systems of seedlings developed aseptically using the two symbionts. Arginine (total) was the major amino acid constituent in the mycelium of B. variegatus (18%–22%) during the exponential phase of growth. While 59%–86% of the available arginine was bound during the acceleration phase of growth, in the logarithmic phase 63%–75% was in the free pool. There were differences in the proportions between the individual amino acids in the bound fraction at different stages of growth suggesting production of diverse proteins. Twenty per cent of the amino acid content of uninfected P. sylvestris root systems was arginine. Infection of the root systems by the fungal symbiont did not result in an increase but a slight decrease in the free arginine content of the composite structure. Almost all other amino acids in the free pool were found in higher concentrations in the mycorrhizal root system. It is suggested that arginine synthesis in B. variegatus is repressed by the arginine available in the host. The mycorrhizal fungus possibly metabolizes the host arginine pool ultimately resulting in more efficient protein synthesis in both the partners.     

Studies on the Nitrogen Metabolism in Ectomycorrhizae

Free and bound amino acids in the mycorrhizal and nonmycorrhizal root systems of Pinus nigra Arnold and Corylus avellna L. grown under semi-natural conditions were analyzed through automatic amino acid analyzers. Tuber brumale Vitt. and T. melanosporum Vitt. were the respective fungal symbionts. Arginine and citrulline were found to accumulate in large quantities in the free pool of the uninoculated P. nigra and C. avellana root systems respectively. In the mycorrhizal root systems these substances decreased in their levels with a parallel increase in the concentrations of glutamine and asparagine. Implications of these changes are discussed with reference to ectomycorrhizae. In general the majority of the identified free amino acids were found in larger concentrations in both the types of mycorrhizal root systems. Results obtained suggested that this may not be due to proteolysis but due to increased biosynthesis. Possible interrelationships in ectomycorrhizal root systems with reference to nitrogen metabolism are presented in the form of a scheme.     

Experimental Studies on Plant Metabolism

Treatment of Ricinus communis seeds with GA accelerated the production of reducing sugars and increased the total carbohydrate content. The effect increased progressively with increasing concentration of GA. — GA treatment also induced an earlier appearance of starch which was shown to be completely absent at the early stages of germination. Furthermore, GA accelerated the conversion of oils into carbohydrates. — Analysis of germinating seeds for their nitrogen content showed that whenever an increase in soluble-N due to GA treatment was detected, there was a decrease in protein-N. Breakdown of protein and formation of soluble-N increased progressively with increase in GA concentration. — GA induced variable changes in the length of the radicles and the hypocotyls, the dry weight and the water content of germinating seeds.     

Studies on the Metabolism of Azuki Seed Protein

In order to investigate the role of a protease in protein metabolism during the germination of azuki seeds, the purification of the portease was carried out by employing fractionation with ammonium sulfate, dialysis against distilled water, and elution chromatography on a column of DEAE-cellulose. The enzyme preparation thus obtained was homogeneous in ultracentrifugal patterns.     

Studies on the Metabolism of D-amino acid in Microorganisms

Several strains of bacteria belonging to genus Aerobacter were found to oxidize D-glutamate rapidly, while tbey show feeble oxidative activity toward the L-form even when they were grown in the medium containing DL-glutamate.

The isolation of L-glutamate, a natural amino acid, from its DL-form was achieved by the degradation of D-glutamic acid using one of these strains.

This may be the first observation on a natural amino acid obtained from the racemic one by the metabolic action of the organism.

A new enzyme, D-glutamic acid oxidase, which is responsible for D-glutamate degradation in this organism and differs from Krebs’ D-amino acid oxidase, has been postulated.     

Studies on the Metabolism of d-Amino Acid in Microorganisms

In the previous paper it was reported that a mold enzyme preparation from Aspergillus ustus strain f., which was found to oxidize d-glutamic acid specifically, was always accompanied by the oxidation of d-aspartic acid. The present study has been carried out to investigate whether or not d-glutamic and d-aspartic acids are oxidized by the same enzyme.

A highly purified enzyme preparation which still shows both activities has been obtained. Several evidences which support the assumption that the both reactions might be catalyzed by a single enzyme, which may be called d-monoamino-dicarboxylic acid oxidase, are also presented.     

Studies on the Metabolism of Gallic Acid by Microorganisms

The intermediary metabolism of gallic acid by Aspergillus niger under the influence of some added inhibitors has been studied. The decomposition of gallic acid by lyophilized cells under fluoroacetate inhibition allowed cis-aconitic acid, α-ketoglutaric acid and citric acid to accumulate. A mechanism of gallic acid decomposition via cis-aconitic acid has been inferred.     

Studies on the Metabolism of d-Amino Acid in Microorganisms

It is confirmed by a new method for the determination of d-glutamic acid, that Aerobacter strain A rapidly metabolizes d-glutamic acid, while it only shows feeble metabolic activity towards l-glutamic acid when it is grown on a dl-glutamate-K₂HPO₄ medium. A specific d-glutamic oxidase is demonstrated in the cell-free extracts of Aerobacter strain A. This enzyme seems to be different from d-glutamic-aspartic oxidase obtained from Aspergillus ustus by the authors, since the former has no activity towards d-aspartic acid.