A New Amino Acid Antibiotic KT–151, Produced by Streptomyces luteogriseus,Strain No. KT–151

From the results of taxonomic studies, Streptomyces sp. strain No. KT–151 isolated from a soil sample collected in Kumamoto City, was identified as a strain belonging to Streptomyces luteogriseus Schmitz, Deak, Crook and Hooper 1964. A new antibiotic, produced by this strain, was isolated as a leaflet crystal by ion-exchange chromatography and found to be an amino acid with the molecular formula, C₅H₁₂N₂O₂, and named antibiotic KT–151 (refered to as KT–151 hereinafter). The antibiotic showed antimicrobial activity against various Gram-positive and Gram-negative bacteria in a chemically defined medium but it was antagonized by several amino acids such as valine, leucine, isoleucine and threonine.     

An Exopolygalacturonase from a Strain of Acrocylindrium

An exopolygalacturonase was partially purified from mycelial extracts of a strain of Acrocylindrium. The enzyme was most active at pH 4.5 and showed a higher affinity for polygalac turo nic acid than for oligogalacturonic acids. The enzyme was found to hydrolyze glycosidic linkages at the non-reducing end of polygalacturonic acid molecules, giving only monogalacturonic acid as the reaction product.     

Isolation,Structure and Physiological Activities of Piericidin B,Natural Insecticide Produced by a Streptomyces

Piericidin B was isolated from mycellia of Streptomyces mobaraensis besides piericidin A. On the basis of IR, NMR and mass spectral studies together with chemical evidences, its structure was assigned as Id. Its physiological activities are also deescribd.     

Landslide-facilitated species diversity in a beech-dominant forest

To evaluate the extent to which landslides affect community dynamics and consequent species diversity in a beech-dominated forest, differences in the composition and size structure of tree species were compared between landslide and adjacent stable (control) stands. Demography and changes in size were compared between the two stands over a 5-year period about 60 years after a landslide. In the control stand, replacement occurred even amongst late-successional species, with beech (Fagus crenata)—the most dominant species—increasing in relative abundance. In the landslide stand, very few large individuals of late-successional species occurred, whereas large individuals of early-successional species occurred only in the landslide stand. The traits indicate that the landslide strongly facilitated species diversity, not only by reducing the dominance of late-successional species, but also by promoting recruitment of early-successional species. However, new recruitment of early-successional species was inhibited in the landslide stand, although we observed succeeding regeneration and subsequent population growth of late-successional species there. As a result, the relative dominance of late-successional species increased with succession after the landslide, thus decreasing future species diversity. In beech-dominant forest landscapes in Japan that include communities with different developmental stages, the mosaic of serial stages may facilitate species diversity after a landslide.     

Tryptophan Metabolism of Rats Fed on an Amino Acid Diet Devoid of One Branched Chain Amino Acid

In an attempt to study on metabolic changes in rats fed on an amino acid diet devoid of one branched chain amino acid and of niacin, rats were force-fed a leucine-free, isoleucine-free, valine-free or complete amino acid diet for 3 or 4 days and killed 3 hr after the feeding on day 4 or 5 to observe the body weight changes, the urinary nitrogen and N¹-methylnicotinamide (MNA), and liver tryptophanpyrrolase (TPase) and tyrosine-α-keto-glutarate transaminase (TKase) activities.

The excretion of the urinary nitrogen and MNA, TPase and TKase activities, and fat content of livers of rats force-fed these amino acid deficient diets were higher than those fed the complete amino acid diet. It was further confirmed in the present study that changes in TPase activity of rats given diets devoid of one essential amino acid were in the same direction with changes in urinary MNA which was observed in the previous studies on rats given threonine-free, tryptophan-free, methionine-free, lysine-free and complete amino acid diets. However, such metabolic changes in rats fed the leucine-free diet were not so remarkable, compared with those of rats fed the other amino acid deficient diets.     

Preparation of UDP-N-Acetylgalactos-amine from UDP-N-Acetylglucos- amine by Bacterial Enzymes

An E. coli strain, SH209, harboring pLC9–12 exhibited 5- to 6-fold higher γ-glutamyltranspeptidase activity than the wild-type strain, at each growth temperature tested. Maximum activity was observed at 20 ~ 25°C, as was observed with the wild type. A homogeneous enzyme preparation was obtained from the periplasmic fraction of the strain by a simple three-step method. The conditions for γ-glutamyl-DOPA synthesis from l-glutamine and l-DOPA were investigated using the enzyme preparation. Under the best conditions, the maximal yield of 79%, equivalent to 158 mm (51.5 g/l) of γ-glutamyl-DOPA as to both substrates, was obtained. γ-Glutamyl-DOPA was isolated from the reaction mixture and identified using an amino acid analyzer after hydrolysis with HCl or γ-glutamyltranspeptidase.     

Continuous ATP Regeneration Using Immobilized Yeast Cells

Arthrobacter simplex was screened as an α-keto-δ-guanidinovalerate (ketoarginine) assimilating organism. A characteristic feature was its growth on ketoarginine as a carbon source; it began to grow after an extremely long lag. Its growth was stimulated by addition of 0.02% yeast extract to the medium.

The results indicated the transamination of arginine-α-ketoglutarate (α-KGA) and the hydrolyzing reaction of ketoarginine into α-keto-δ-aminovalerate and urea. Two intermediates, ketoarginine and α-keto-δ-aminovalerate, were isolated and identified by various procedures. Coupling of the two reactions was demonstrated in cell-free extracts of arginine-grown cells; ketoarginine formed from arginine by transamination with α-KGA was hydrolyzed directly to α-keto-δ-aminovalerate and urea. The metabolic routes of arginine in microorganisms were discussed.     

Isolation and Restriction Mapping of a Pseudomonas Plasmid

The effects of the injection of a large amount of N¹ -methylnicotinamide (MNA) (500 mg per kg body weight) on the ratio of N¹ -methyl-4-pyridone-3-carboxamide (4-py) to N¹ -methyl-2-pyridone-5- carboxamide (2-py) excretion, and the activities of 2-py and 4-py forming MNA oxidases were investigated in rats. The injected MN A was excreted very rapidly into the urine; 46 % of the dose was excreted from 0~3hr post-injection, 15% from 3~6hr, 6% from 6~9hr and 1.5% from 9~ 12hr. The ratio of 4-py to 2-py also decreased rapidly; the ratio being about 0.6, 0.4, 0.4 and 0.6 from 0~3hr, 3~6hr, 6~9hr and 9~ 12hr post-injection, respectively. This ratio then recovered rapidly; being about 2, 5.5, 8.5 and 9.7 from 12~24 hr, 24 ~48 hr, 48~72 hr and 72 ~96 hr post-injection, respectively. The normal range of 4-py to 2-py excretion ratio is 8~14. So, this ratio returned to a normal level by day 3 post-injection. The rats were killed 5 hr after the MNA injection. At this time (the lowest ratio was observed around this time), the activities of 2-py and 4-py forming MNA oxidases in the injected group were 59 % and 11 % of the normal levels, respectively. Therefore, it was found that the decreased ratio of 4-py to 2-py excretion with the MNA injection was mainly due to the higher inhibition of the 4-py forming MNA oxidase than of the 2-py forming MNA oxidase by the MNA injection.     

Structure–activity relationships of 6-(aminomethylphenoxy)-benzoxaborole derivatives as anti-inflammatory agent

A series of novel 6-(aminomethylphenoxy)benzoxaborole analogs was synthesized for the investigation of the structure–activity relationship of the inhibition of TNF-alpha, IL-1beta, and IL-6, from lipopolysaccharide stimulated peripheral blood mononuclear cells. Compounds 9d and 9e showed potent activity against all three cytokines with IC₅₀ values between 33 and 83 nM. Chloro substituted analog 9e (AN3485) is considered to be a promising lead for novel anti-inflammatory agent with a favorable pharmacokinetic profile.