Role of Some Hormones in Protein Sparing Action of Dietary Fat

Feeding rats with a fat meal caused marked reduction in the level of plasma urea and urinary output of urea and total nitrogen. Experiments were carried out to examine the possible intervention of some hormones in these phenomena. Protein sparing action of fat was exerted even in the alloxan-diabetic, adrenalectomized, hypophysectomized and thyroidectomized rats. Feeding rats with a fat meal caused no appreciable change in the level of cyclic AMP in liver and gastrocnemius muscle. The overall results obtained here are through! to suggest that the action of fat may be exerted independently of any hormones examined; insulin, glucocorticoids, cyclic AMP and other hormones excreted from adrenal, hypophysis and thyroid gland.     

Epiderstatin and Its Related Glutarimide Antibiotics Inhibit the Cell Growth Induced by Mitogen Stimulation

To investigate the immunosuppressive effects of glutarimide antibiotics including a new antibiotic named epiderstatin, we tested these antibiotics for inhibition of the blastogenesis of mouse spleen cells induced by mitogen stimulation (concanavalin A or lipopolysaccharide). The inhibitory activity was measured by colorimetric MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. Among the glutarimide antibiotics tested, epiderstatin and acetoxycycloheximide especially strongly inhibited the blastogenesis of mouse spleen cells induced by concanavalin A and lipopolysaccharide, however, selectivity between T and B lymphocytes was not observed.     

Studies on l-Threonine Fermentation

Fifteen strains of bacteria were treated with ultraviolet light or N-methyl-N′-nitro-N-nitrosoguanidine to derive auxotrophic mutants, which were screened for their ability to produce l-threonine. A number of auxotrophs were derived from each strain. Among them, those which produced a large amount of l-threonine were found in Aerobacter aerogenes, Serratia marcescens and Escherichia coli, the members of the family Enterobacteriaceae. Nutritional requirements of these threonine producers were proved to be methionine, lysine, or α, ε-diaminopimelic acid (DAP).

In A. aerogenes and E. coli, double and triple auxotrophs were derived with futher mutational treatment. As a, rule, imposition of additional block led to the increase of l-threonine production. In E. coli, many triple auxotrophs (DAP^?, Met^?, He^?) and their isoleucine revertants were screened for their ability to produce l-threonine. Enhancement of l-threonine production was achieved with these mutants.

One of the isoleucine revertants, KY8280, was used to investigate some cultural conditions. As a result, l-threonine accumulation reached to a level of 13.8 mg/ml with the medium containing 7.5% fructose.     

Fatty Acids as Inhibitors of Microbial Cell Wall Synthesis

The Maillard reaction of DNA with ketoses was investigated. Several days of incubation of d-fructose 6-phosphate with deoxyribonucleotides or with polymer DNA in an aqueous buffer resulted in the formation of chromophores and fluorophores. Aminoguanidine and sodium cvanoborohydride inhibited the formation of fluorophores. Transition metal ions such as Cu²⁺, Fe³⁺, Fe²⁺, or Mn^{2 +} promoted the formation of chromophores and fluorophores. Metal-chelating agents such as DETAPAC, citrate, and Desferal inhibited the formation of fluorophores. Superoxide dismutase and catalase also inhibited the formation of fluorophores. The transition metal ion-catalyzed autoxidation of d-fructose 6-phosphate or of the Heyns rearrangement products were to be partially involved in the glycation of DNA and subsequent formation of chromophores and of fluorophores.     

Antitumor Lipopolysaccharide from Heptoseless Mutant of Proteus mirabilis

Studies on lipopolysaccharide (LPS) from the cells of Proteus mirabilis RMS-203 were focused upon reduction of lethal toxicity and of pyrogenicity by biological and chemical modification. A heptoseless mutant, strain N-434, was isolated by the use of phage resistancy as a tool. LPS from that heptoseless mutant was completely deficient in neutral sugars and mainly composed of 2-keto-deoxy-octonic acid (KDO), glucosamine and fatty acids. It revealed almost the same antitumor activity as LPS of the wild type but it was less toxic and less pyrogenic.

Hydroxylaminolysis and reduction with LiAlH₄ resulted in removal of fatty acids from LPS accompanied with decrease in lethal toxicity and antitumor acitivity but not in pyrogenicity.

Lipid A fractions showed almost the same antitumor activity as intact LPS but less lethality and less pyrogenicity.     

Accumulation of Xanthine Derivatives in the Culture Broths of Bacteria Incubated with Decoyinine

The present report describes the successful isolation procedure and some physico-chemical properties of an unknown blue-violet fluorescent substance existing in spinach leaves. Through the isolation steps of water extraction of leaves (200 kg), active carbon adsorption, extraction by organic solvents, and column chromatographies with various adsorbents and ion exchange resins, a purified compound was obtained in colorless planeary crystal of long parallelogram (40 mg; mp. 195°C; C₁₃H₁₇O₉N₁). The UV-, IR- and NMR-spectra, the results of organic tests, and behaviors on chromatographies and electrophoreses are presented.     

Studies on Polyoxins,Antifungal Antibiotics

Seven additional components, polyoxins C, D, E, F, G, H and I were isolated from polyoxin complex. They have molecular formulae corresponding to C₁₁H₁₅N₃O₈, C₁₇H₂₃N₅O₁₄, C₁₇H₂₃N₅O₁₃, C₂₃H₃₀N₆O₁₅, C₁₇H₂₅N₅O₁₂, C₂₃H₃₂N₆O₁₃ and C₁₉H₂₄N₄O₁₂, respectively. These polyoxins except inactive polyoxins C and I were highly active against various kinds of phytopathogenic fungi. The close structural similarity among them including polyoxins A and B is also discussed.