Chemical Structure of Piericidin A

Molecular formula C₂₅H_37–39NO₄ was assigned to Piericidin A. Through the examination of the ultraviolet, infrared and n.m.r. spectra and of chemical evidences, it was shown that Piericidin A contains one secondary alcohol, one acidic hydroxyl group, two methoxyl groups, tri- and tetra-substituted conjugated dienes and one polysubstituted heteroaromatic ring.     

The Structure of Destruxin B,a Toxic Metabolite of Oospora destructor

The viability of freeze-dried Lactobacillus bulgaricus B-1 was affected by rehydration temperature, and maximum recovery of the viable cells was obtained when they were rehydrated at 20 to 25°C. Cellular ribonucleotides leaked out from the freeze-dried cells during rehydration, but there was no correlation between the viability of cells and the amount of leaked substances. Rehydration of the freeze-dried cells in the presence of RNase caused marked loss of viability. These results suggest that the cell surface was damaged by freeze-drying and its selective permeability was lost to some extent.     

Structure of a Peptidal Antibiotic P168 Produced by Paecilomyces lilacinus (Thom) Samson

( + )-α-Kainic acid (1) was synthesized by starting from a building block, N-Boc-3-acetoxyallylglycine ethyl ester (2). The key intermediate, a methyl 4-[(tert-butoxycarbonyl)prenylamino]-5-hydroxy-2-pentenoate derivative (9), was prepared from 2 in eight synthetic steps. After converting 10 into a methyl ester (11), intramolecular ene-carbocyclization of 11 gave a pyrrolidine derivative (12), which was converted to 1 in a moderate yield.     

Herbicidal Activity of Some Pyridazine Derivatives

Herbicidal activity of some 50 pyridazyl ethers was evaluated. Among them, 3-chloro-6-(2-phenylphenoxy)-, 3-chloro-6-(2,6-dichlorophenoxy)-, 3-chloro-6-(3-methoxyphenoxy)- and 3-chloro-6-(4-methoxyphenoxy)-pyridazines showed conspicuous effectiveness on radish and millet in pre-emergence test, whereas postemergent activity of the compounds tested was not so remarkable in general. Relationships between herbicidal activity and chemical structure are discussed.     

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.     

Studies on the Metabolic Products of Oospora sp. (Oospora astringenes)

The chemical structure of oospolactone which is the metabolic product of Oospora astringenes was confirmed by the synthetical approach.     

Synthesis of Pyridazine Derivatives as Herbicides

Series of 3-chloro-6-phenoxy- and 3,6-bisphenoxypyridazines were prepared from 3,6-dichloropyridazine to be evaluated as herbicides. Certain thioethers were also prepared.     

Chemical Studies on “Clover Sickness”

Two new isoflavonoids were isolated from red clover as germination inhibitors for the same plant and their structures were determined as a glucoside of biochanin A (7-d-β-glucosyl-5,7-dihydroxy-4′-methoxyisoflavone) (II) and its 5-malonate (I), respectively. Besides these compounds the following substances were also isolated as inhibitors: trifolirhizin (III), ononin (IV), daidzein (V) and its 7-glucoside (VI), formononetin (VII), genistein (VIII) and biochanin A (IX).     

Induction of Catalase Activity by Hydrocarbons in Candida tropicalis рK 233

1. The catalase activity of Candida tropicalis pK 233 was induced by hydrocarbons but not by glucose, galactose, ethanol, acetate or lauryl alcohol.

2. The induction of the catalase activity depending upon hydrocarbons was sensitive to cycloheximide but not to chloramphenicol.

3. Glucose repressed strongly the induction of the catalase activity by hydrocarbons but galactose did not affect seriously.

4. When C. tropicalis was incubated with hydrocarbons, the appearance of microbodies was observed electronmicroscopicaliy.

     

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.