Cells of Streptococcus laths grown at 10°C and harvested were disintegrated and lyphoilized for extraction of total lipids. The extracted lipids were separated into neutral and complex lipids by silicic acid column chromatography and recovered to determine their yields. Complex lipids were fractionated into glycolipids and phospholipids by silicic acid column chromatography and on silicic acid-impregnated papers. Total lipid contents in dried cells of the bacterium amounted to about 5%, and the proportion of neutral to complex lipids was about 20 to 80, irrespective of growth temperatures (10 and 30°C). Seven components in complex lipids were divided into three of glycolipids and four of phospholipids on the chromatogram. The variations in the yields of the components were due to the growth medium composition. It was found that glycolipid contents of bacterial cells were considerably higher. The fatty acid composition of neutral lipids and phospholipids was clearly affected by growth temperatures, and at 10°C, unsaturated acids (C¹⁼_l6 and C¹⁼₁₈) increased and lactobacillic acid (cy-C₁₃) decreased.

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Lipolytic activities of intracellular lipase obtained from Streptococcus lactis 527 cells grown at 30°C were determined using bacterial neutral lipids extracted from cells grown at 10 and 30°C. The amounts of free fatty acids liberated from lipids by lipase were in the order: 30°C neutral lipid>10°C neutral lipid>triolein>intracellular membrane fraction. Glycerides hydrolyzed partially by lipase were detected on thin-layer plates and were composed of 1, 3-and 1, 2-diglycerides, fatty acids and unhydrolyzed triglycerides. Fatty acids liberated from neutral lipids by lipase were determined by gas chromatography. It was found that the major acid was cy-C₁₉ and the minor C^l=₁₈ among the acids liberated from 10°C neutral lipid, whereas the major acid was C¹⁼₁₈ and the minors C¹⁼₁₆ and cy-C₁₉ from 30°C lipid.

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This investigation was undertaken to clarify ultrastructure of Cheddar cheese texture and morphological changes in lactic acid bacteria firmly embedded in cheese. Fine structures of Cheddar cheese ripened for 5 months, sliced into ultra-thin sections were observed with an electron microscope. Cheese bacteria were often found crowded around larger fat globules in limited regions of cheese. Shapes of living cells were short and rod-like. Cell walls, cross-wall sections and several organelles were distinctly observed in living cells. Intact cells were recognized to be clearly differentiated from dead cells by morphological changes. The occurrence of cell wall lysis characterized dead cells, and segments of cell walls were released from cells and curled nearly after lysis. Unit membranes of protoplast were also maintained without bursting. Moreover, protrusion of cell contents from protoplasts was also found in the cells from which parts of cell wall had been released.

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The effect of exogenous fatty acids on cell growth and death of the biotin-requiring yeast Saccharomyces cerevisiae BA-1 was examined with respect to the mechanism of synthetic pathway of fatty acid under biotin starvation. At a growth temperature of 30°C, exogenous unsaturated fatty acids, such as palmitoleic, oleic, linoleic, and linolenic acids which promote the cell growth and suppress death effectively, were incorporated intactly into the cellular fatty acids, whereas the saturated fatty acid, palmitic acid, which supports growth but some what inhibits death, was once incorporated, and about 60% of incorporated palmitic acid was found to be desaturated. However, at an elevated temperature of 36°C, even palmitic acid showed similar effects to unsaturated fatty acids in cell growth and death; followed by an increased desaturation of palmitic acid. Thus the data indicate that palmitic acid, as well as unsaturated fatty acids directly compensate for the deficiency of endogenously synthesized fatty acids caused by biotin starvation.

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An α-glucosidase which was homogeneous in ultracentrifugal and disc electrophoretic analyses was purified from sugar beet seed by fractionation with ammonium sulfate, chromato-graphy on CM-cellulose and gel filtrations on Bio-Gel P-150. The sedimentation coefficient (S_{20, w}) was calculated to be 5.9S. The molecular weight was estimated to be approximately 9.1×10⁴ by SDS-disc electrophoresis.
The α-glucosidase showed also the pronounced glucoamylase activity. The optimal pH was found to be in the range of 4.1 to 4.7 for both maltose and soluble starch. The enzyme exhibited higher substrate-binding affinity and hydrolytic activity toward soluble starch than toward maltose. The ratio of initial velocity of hydrolysis for maltose (Km, 6.8 mg/ml) and soluble starch (Km, 1.9 mg/ml) was calculated to be 100:120 in this order. The enzyme is an interesting type of α-glucosidase which may be regarded as glucoamylase.

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Initial stage of organic solvent-induced autolysis in yeast was studied with ¹⁴C-acetate labeled cells. In the case of toluene-induced autolysis, primary cell injury which was estimated by leakage of UV absorbing substances from cell accompanied rapid deacylation of phospholipids. Lysophospholipids did not occur during autolysis. When autolysis was induced by addition of ethyl acetate, phospholipids of yeast cells were not degraded so much. Ethyl acetate rather inhibited yeast phospholipase activity under the condition tested.

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When a solution of purified mitochondrial phenol oxidase from spinach leaves has been stored frozen, the Michaelis constant decreased with the lapse of time after thawing of the frozen enzyme solution, and reached a constant value, 4.7×10^-3M, in 2.5 hr. Immediately after thawing of the frozen enzyme solution, the oxidation of catechol catalyzed by the phenol oxidase was competitively inhibited by p-substituted phenols. The enzyme kept for 2.5 hr after thawing was allosterically inhibited by p-substituted phenols. These results suggest that the conformation of the enzyme changes with the lapse of time after thawing. However, a differential spectral study of the enzyme immediately after thawing and that 2.5 hr after thawing did not indicate any appreciable change of optical density in the range of 260_??_350nm.

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α-Amylase (EC 3.2.1.1) and β-amylase (EC 3.2.1.2) were isolated and purified, each to a state free from contaminating enzymes, from the barley malt and ungerminated barley grains, respectively. Starch granules, isolated from the same sources, served as substrates to study the mode of action of amylases on the digestion of starch granules in vitro. β-Amylase alone had a very small activity on starch granules and formed maltose as a sole digestion product. α-Amylase played a major role in the digestion of starch granules and the combined action of α- and β-amylases was more effective than the action of α-amylase alone, but was less effective, on the same enzyme activity basis, than the crude extract from barley malt, which was thought to represent in vitro the enzyme system for the digestion of starch granules in the germinating barley grains. The possible roles to be played by a debranching enzyme, α-glucosidase and/or glucosyl- or glucanotransferases are discussed.

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Isoamyl acetate was enzymatically synthesized from acetyl-CoA and isoamyl alcohol with the cell-free extract from Cladosporium cladosporioides No. 9. The acetic-ester synthesi-zing enzyme was fractionated from the cell-free extract by procedures including (NH₄)₂SO₄ fractionation, gel filtration on Sephadex G-150, and column chromatography on DEAE-Sephadex A-50. This enzyme was homogeneous on SDS gel electrophoresis and its molecular weight was approximately 22, 000. The enzyme was obtained in about 50-fold purification in specific activity over that of the cell-free extract. The enzyme was most active at pH 6.0 and 25°C, and was relatively stable between pH 6.0 and 7.5.

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The inhibitory activity of tunicamycin against Newcastle disease virus multiplication was partially reversed by lipids. Phosphatidylcholine, lauric acid and monoglyceride of lauric acid showed the most significant recovering activities among all the tested. But the recovering activity was not observed when tunicamycin was added at a concentration 12-fold greater than the minimal inhibitory concentration. The synergistic effect of phosphatidyl-choline and N-acetyl-D-glucosamine in the recovery indicates different mechanisms of recovery by the two compounds. Recovery of virus multiplication by lipids was suggested to be caused by incorporation of tunicamycin into lipid micelle and decrease of available tunica-mycin in the medium.

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An antibiotic, hygromycin (homomycin), was studied by proton and carbon magnetic resonances as well as chiroptical techniques to determine the absolute configuration since some aspects have been remained uncertain. The location of a methylene substituent is concluded on C-4 and C-5 position of neoinosamine-2 by the cuprammonium method and the exciton chirality rule. The proton NOE experiment suggests a trans-configuration of the 2-methyl-caffeic acid moiety. A rather unusual glycosidic stereochemistry of cis β-D-arabino-hexofu-ranoside configuration is determined by recently advanced CMR techniques and the absolute structure of the antibiotic has been assigned as I.

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The structure of S-1358, a potent fungicide toward powdery mildew, has been established by X-ray crystallography as the syn configuration regarding the 3-pyridyl and the S-p-tert-butylbenzyl groups about the N=C bond. On the other hand it instantly gave rise to an equilibrium mixture of the anti and the syn isomers in a number of different solvents (even under deep freezing conditions). The NMR signal due to the benzylic methylene protons could be resolved into two ringlets below -14°C. The isomer (topomer) ratio was dependent linearly on 1/T, and it was also affected by the bulkiness of the S-alkyl group in a series of the analogs. Fungicidal activities of S-1358 and its analogs are discussed in connection with the topomer ratios.

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Influence of buffer action on the acetic acid concentration in culture liquid was investigated. In the fermentation where pH was controlled at a constant level by the addition and consumption of acetic acid, acetic acid concentration in culture liquid changed greatly by the shift of pH value to be controlled. This change was mainly brought about by the action of buffer, i.e. greater the buffer value of culture liquid, bigger the change in acetic acid concentration at the same pH shift. In the range of pH beyond 7.5, buffer effect due to carbon dioxide-bicarbonate buffer was predominant over the one due to cellular protein or medium components.
This knowledge was useful for the control of acetic acid concentration in culture liquid.

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Twenty amines were examined as catalysts for the phosphorylation of ribonucleoside by MTBO.
Primary n-alkyl and alicyclic amines were good catalysts giving the product in high yields. Branched-chain alkylamines were less effective than straight-chain alkylamines. While secondary amines were less effective than primary amines, the yields of the product were nearly equal to those with primary amines. Cyclic imines, except for morpholine, had high catalytic activities though the yields of the product were low. Tertiary amines were the least effective catalysts.

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This paper presents evidence for the occurrence of a trypsin inhibitor in buckwheat grain. Trypsin inhibitor activity distributed uniformly in the whole buckwheat grain. The inhibitor, prepared from aqueous extracts of buckwheat grain by the combined procedures of heat treatment, salting-out and gel filtration, appeared to be a protein-like substance. The inhibitor exhibited significant inhibitory capacity against trypsin and α-chymotrypsin, but less against pepsin, papain, ficin and Nagarse. The inhibitor was relatively thermostable, and highly resistant to acid; susceptibility to pepsin action was so limited to such an extent as to lose about half of its original inhibitory activity. The trypsin inhibitor in buckwheat grain disappeared substantially during germination.

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Two hydrolases hydrolyzing separate synthetic substrates, N-α-benzoyl-n, L-arginine p-nitroanilide (BAPA) and leucine p-nitroanilide (LPA), were purified 230-fold from dry pea seeds by ammonium sulfate fractionation, heat treatment, DEAE-cellulose and Sephadex G-100 column chromatographies, and isoelectric focusing; one of them (BAPAase) hydrolyzed BAPA, and the other (LPAase), LPA. BAPAase and LPAase were separated from each other by DEAE-cellulose column chromatography. Both enzymes were none of metallo-, serine- and thiol-type enzymes, and BAPAase, but not LPAase, was activated by divalent cations. Both enzymes had no ability to hydrolyze globulins prepared from the seeds. Neither BAPAase nor LPAase activity in the cotyledons changed during 5 days of germination. The levels of both hydrolases were not influenced by the removal of embryo at 4-hr imbibition stage, or by supply of cycloheximide to the seeds. It is concluded that neither BAPAase nor LPAase participates in the initial breakdown of reserve proteins.

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Levansucrase of Bacillus subtilis var. saccharolyticus was purified from the supernatant of an aerobically incubated suspension of the grown cells in a dilute sucrose solution by chromatography on a column of DEAE-cellulose.
The synthesis of levan by the purified enzyme resulted in most effectively at low temperatures at around 0°C, and the levan synthesized was isolated by passing the enzyme-reaction mixture through a DEAE-cellulose column followed by ethanol precipitation. The levan was isolated in the pure state ([a]²⁰_D-47] and its molecular weight was determined to be 2×10⁴ by the gel filtration method.

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The structure of two new nor-isoprenoids, diastereomers of 1, 4-epoxy-2, 10-dihydroxy-7-isopropyl-4-methyl-5E-undecene, isolated from Japanese domestic SUIFU tobacco, has been determined mainly by ¹³C-NMR, ¹H-NMR and high resolution MS. The carbon skeleton of the new compounds indicates that they are derived from thunbergane precursors.

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Production of extracellular polysaccharidases by Irpex lacteus Fr. was studied in different culture conditions.
The presence of fatty acids such as linolic, linolenic, erucic, palmitic acids etc. caused remarkably to increase the production of cellulase (filter paper disintegrating activity, FD), laminarinase and xylanase. On the contrary, fatty acids had not any special effect on the production of cellulolytic enzymes such as Avicelase and CMCase and of plant tissue macerat-ing enzymes (MA).
When two kinds of carbon sources, e. g., cellulose powder and potato pulp were mixed together and used as an inducer, polysaccharidase production investigated, with the exception of CMCase, increased higher than when the two substances were used separately.

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The filter paper disintegrating activity (FD) and the plant tissue macerating activity (MA) in the enzyme preparation (Driselase, DRS) produced by Irpex lacteus Fr. (KY2902) were studied.
Optimum pH value of FD was 3.5_??_5.0 and that of MA was 4.0_??_6.0. Optimum temperature of FD was 45°C and that of MA was 40_??_45°C. Both FD and MA were stable in a wide pH range investigated and they were thermostable up to 45°C. FD was remarkably inhibited by Ag¹⁺ Hg²⁺ and Sn²⁺; on the other hand, MA was not affected by any of metal ions tested.
DRS exhibited high cellulase, hemicellulase and pectinase activities, but its excellent points were characterized by multiple enzyme systems that were able to be represented by e, g. MA and soybean meal disintegrating activity (SD).
Using various grains, it was examined with a microscope how tissues were macerated and cell walls were disintegrated with DRS.

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The effects of supplementation of enzyme preparation (Driselase, DRS) produced by Irpex lacteus Fr. (KY 2902) on feeding animals were studied.
When 0.01_??_0.03% of DRS were supplemented to broiler diets which contained about 60% corn, body weight gain and feed conversion were significantly improved at 10% and 5% level, respectively. When 0.01_??_0.03%. of DRS were supplemented to broiler diets which contained about 60% of barley, body weight gain and feed coversion were also improved significantly at 1% level each. DRS supplementation improved feed efficiency of barley to the level of corn.
In case of piglets when 0.01% of DRS was supplemented to artificial milk, body weight gain increased significantly at 5% level. Feed conversion was improved about 9%. The digestibility of crude protein, fat and fibre in the ration increased by about 2.4%, 1.7% and 6.3%, respectively.

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The structure of an arabinoxyloglucan, separated from the hemicellulosic polysaccharides of the midrib of the leaves of Nicotiana tabacum, was investigated by methylation analyses before and after mild acid hydrolysis, acetolysis and cellulase-degradation.
The arabinoxyloglucan consists of L-arabinose, D-xylose and D-glucose in a molar ratio of 13:33:54, and has a backbone of β-(1→4)-linked D-glucopyranosyl residues. Some of the glucopyranosyl residues are attached at the 6 position by single α-D-xylopyranosyl and α-L-arabinofuranosyl-(1→2)-α-D-xylopyranosyl side chains.

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In the course of systematic studies of cellulose cigarette smoke, carbonyl compounds extracted with aqueous sodium bisulfite solution were examined and 63 compounds-15 furans, 13 cyclic ketones, 8 lactones, 7 benzene derivatives, and 20 aliphatic ketones, aldehydes and other compounds-were either positively or tentatively identified. Of these 63 compounds, 45 were identified for the first time in this study in cellulose pyrolyzate. Semi-quantitative estimation of some of these compounds revealed that 2-hydroxy-3-methyl-2-cyclopenten-1-one (cyclotene) was the most abundant, followed by 1-hydroxy-2-propanone (acetol), 2-furaldehyde, 1-hydroxy-2-butanone, cyclopentan-l, 2-dione, etc., in decreasing order. Compo-unds possessing pleasant caramel-like odor were found to be relatively abundant both in number and quantity.

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The dough prepared with “Kansui, ” a mixture of alkali carbonates, was observed to show characteristic rheological properties in various extensographic tests. The characteristic properties of the dough were retained even after the dough was neutralized. However, previous addition of SH reagents such as PCMB to flour for making “Kansui” dough, resulted in no such theological properties, and the results are discussed.

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To clarify the mechanism of the γ-L-glutamylpeptide formation in the L-glutamic acid fermentation with Corynebacterium glutamicum, γ-glutamylpeptide synthetic activity of the intact cells and the cell extracts of the bacteria was studied. γ-L-Glu-L-Glu and other various γ-glutamylpeptides were formed by these crude preparations under high substrate amino acid concentrations without direct or indirect biological energy supplying systems. It was re-vealed that these enzyme preparations possessed strong hydrolytic activity to γ-glutamyl-peptides, and that notable amounts of these peptides could be formed by the reverse reaction of the hydrolysis. These reactions were found to be catalyzed by an enzyme. To give the evidence, the equilibrium constants of the hydrolysis of γ-L-glutamylpeptides, the substrate specificity and the distribution of the enzyme among various strains of the bacteria were studied. The partial purification of the enzyme gave sufficient proof to the idea. The mecha-nism was thought to contribute to the γ-L-GIu-L-Glu formation in the fermentation.

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The enzyme of Corynebacterium glutainicum that catalyzes the formation of various γ-L(D)-glutamylpeptides by the reversal of hydrolysis was found to be γ-glutamyltranspepti-dase. The enzyme catalyzed γ-L(D)-glutamyl transfer reaction from various γ-L(D)-glutamyl-peptides including glutathione. The susceptibility of D-isomers was 17% of that of L-isomers. Many kinds of α-L-amino acids and peptides such as γ-L-Glu-L-Glu could be γ-glutamyl ac-ceptors. These findings offered full explanation on the formation of γ-L-glutamylpeptides in the L-glutamic acid fermentation. In the supposed mechanism, γ-L-GIu-L-Glu is formed mainly by the reversal of hydrolysis from L-glutamic acid being richly produced by the bacteria. The other four minor peptides are formed by the γ-glutamyltranspeptidation from γ-L-Glu-L-Glu to some α-L-amino acids and to γ-L-GIu-L-Glu itself in the broths. The enzyme was found to be widely distributed among bacteria, especially in some strains of Corynebacteriun, Bacillus, Erwinea, Serratia, Pseudomonas, Achromobacter, and Alcaligenes.

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The chemical components of ribonuclease L (RNase L) from Aspergillus sp. were tested in order to clarify the structure of the enzyme. The molecular weight and the number of the total amino acid residues of the enzyme were about 4.5×10⁴ and 393, respectively. The amino- and carboxyl-terminal amino acids of the enzyme were determined to be glycine and threonine, respectively. RNase L contained about 6% of neutral sugars and an glycopeptide was obtained by digestion with pronase. The isoelectric point of the enzyme was 3.47.

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Improvements were found in the inosine productivity of Brevibacterium ammoniagenes KY 13714, which is an adenine leaky and 6-mercaptoguanine resistant mutant. A highly productive mutant, KY 13761, was selected after the addition of 6-methylthiopurine resistance and guanine requiring character to KY 13714 and after repeating single colony isolation.
Culture conditions for the practical production of inosine were investigated using KY 13761. It was found that the concentrations of phosphate, magnesium, and adenine were important. Carbon sources and natural nutrients also showed profound effects on inosine accumulation. Especially, effective was the feeding of inverted molasses and urea for pro-duction of inosine. Under optimal conditions, 31 mg of inosine per ml was accumulated after 42 hr cultivation in a 5 liter jar fermenter at 32°C. A growth-associated type of accumu-lation was confirmed in inosine production with KY 13761.

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Direct gas chromatographic determination of tobacco smoke was developed. Tobacco smoke condensate was collected on a glass fiber filter and the components were converted into their trimethylsilyl derivatives and then subjected to glass capillary column gas chromatography. By this method, all tobacco smoke components, including unstable phenolic substances and water-soluble polyhydroxy compounds, were simultaneously determined. Compositional differences between lamina and midrib smoke of flue-cured tobacco leaves were also clarified by the method. The results indicate that there are quantitative differences in nicotine, phenols, levoglucosan, quinic acid γ-lactone and the other major components between lamina and midrib smoke.

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Among examined microorganisms which have ability to decompose cholesterol, Nocardia corallina IFO 3338 converted cholesterol to 3-oxobisnorchola-1, 4-dien-22-oic acid (BDA) at the conversion rate of 63%. The conversion product was identified as BDA by ¹H-NMR, ¹³C-NMR, UV, IR, MS and elemental analysis.
The presence of chelating agents or some metal ions was necessary for the accumulation of BDA. The most effective agents for the accumulation were α, α'-dipyridyl and o-phenan-throline.
For the production of BDA, cholestanol, β-sitosterol, soy sterol (mixture), cholest-4-en-3-one and lithocholic acid could also be used as substrates other than cholesterol,

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Two kinds of β-D-glucans and an acidic heteropolysaccharide were isolated from the fruit body of Auricularia auricula-judae, and their structural features were elucidated. A water soluble glucan ([α]D -10°) consists of a backbone chain of β-(1→3)-linked D-glucose residues, two out of three glucose residues being substituted at the C-6 positions with single glucose units. The other glucan, which was obtained as the hot alkali insoluble residue, is also β-(1→3)-glucan with single branches at C-6 positions, but it has an extremely highly branched struc-ture; a small proportion of (1→6)-internal linkages may be situated in the side chains.
An acidic heteropolysaccharide ([α]D -20°), isolated from the hot water extract through insoluble complex formation with cetylpyridinium chloride, contains D-xylose, D-mannose, D-glucose and D-glucuronic acid (molar ratio, 1.0:4.1:1.3:1.3). Methylation followed by acid hydrolysis of the polysaccharide yielded 2, 3, 4, 6-tetra-O-methyl-D-mannose(glucose), 2, 3, 4-tri-O-methyl-D-xylose, 2, 4, 6-tri-, 4, 6-di-, and 2, 4-di-O-methyl-D-mannose, 2, 4-di-O-methyl-D-glucose, together with 2, 3, 4-tri-O-methyl-D-glucuronic acid, suggesting that it consists of a backbone chain of (1→3)-linked mannose residues, which are attached with D-xylose, D-mannose and D-glucuronic acid residues at the C-2 or C-6 positions.
On the basis of these findings, the constitution of the A. auricula judae was compared with that of Tremella fuciformis.

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An unknown polyacetylene was isolated from the subterranean stems of Solidago altissima L. in which the two polyacetylenes, dehydromatricaria ester (I) and methyl 10-[(Z)-2-methyl-2-butenoyloxy]-(2Z, 8Z)-2, 8-decadiene-4, 6-diynoate (II) had already been found, and its structure was identified as (4Z)-2, 4-decadiene-6, 8-diyn-4-olide (dehydromatricaria lactone) (III). The lactone (III), as well as I, strongly inhibited the growth of the seedlings of barnyard millet (Panicum crus-galli L. var. frumentaceum TRIN.).
The seasonal variations in the polyacetylene contents of the subterranean stems were closely investigated, with the results that III occurred only in the fall of the year while I and II hardly varied throughout the year. II was a major polyacetylene component and the content was 0.9_??_1.0 μmol/g fresh wt.

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The essential oil of Mentha candicans Miller, obtained by solvent extraction, was found to contain predominantly (+)-trans-sabinene hydrate, accompanied by a small amount of (+)-cis-sabinene hydrate; the latter compound was for the first time isolated as a naturally occurring monoterpene. When the oil was obtained by the usual steam distillation, transsabinene hydrate was isomerized to terpinen-4-ol, the content of which increased markedly with prolonged distillation. The other components of this oil were α-pinene, β-pinene, sabi-nene, 1, 8-cineole, γ-terpinene, p-cymene, 3-octanol, menthol and α-terpineol. These findings indicate that Mentha candicans is a new chemical strain of Section Spicatae.

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Growth characteristics and cell composition of Alcaligenes eutrophus under limitation of gaseous substrates were evaluated in a chemostatically controlled continuous culture. Yield coefficients, especially Y_H2, and cell composition varied conspicuously with the change of growth limiting gas from hydrogen to oxygen. In O₂-limitation, Y_H2 was 1.5 times higher than that in H₂-limitation but the content of protein in cell decreased. With feeding the gas-mixture containing H₂:O₂:CO₂=3:1:0.4, simultaneous limitation of three gases was suspected to occur. With this feeding ratio of gases, highest productivity of cell mass and efficient utilization of gaseous substrates were obtained.

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(+)-Cyanofenphos was at least more than 25-fold as toxic to rice stem borer larvae as the (-)-isomer. In addition, (+)-cyanofenphos-oxon was 36-fold more potent inhibitor than the (-)-oxon toward rice stem borer larva acetylcholinesterase. The (+)-, (-)- and racemic forms of cyanofenphos were metabolized in rice stem borer larvae at almost equal rates. However, (+)-cyanofenphos produced 4- to 9-fold larger amounts of cyanofenphos-oxon in the insect body than the (-)-isomer. On the other hand, (-)-cyanofenphos-oxon was meta-bolized to 4-cyanophenol and its conjugate at a faster rate compared to the (+)-oxon. The difference in toxicity to rice stem borer larvae exhibited by the optical isomers of cyanofenphos is attributable to the difference in the amount and persistence of cyanofenphos-oxon isomers formed in the insect body as well as in anti-acetylcholinesterase activity of the oxon isomers.

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Phenylthioacetone (1), (±)-phenylsulfinylacetone (5) and phenylsulfonylacetone (3) were reduced by fermenting bakers' yeast to produce the corresponding alcohols of (S)-configura-tion. Sulfone 3 was reduced most readily. Reduction of (±)-5 gave a mixture of (S)-5 and (S)_c-(R)_s-2-hydroxypropyl phenyl sulfoxide (6), showing that (R)-5 is reduced more easily than (S)-5. The order of reducibility of four sulfur analogs is shown as 3>(R)-5>1>(S)-5.

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A new alkaloid named stemospironine (I) was isolated together with stemofoline (II) as the main insecticidal constituents of leaves and stems of Stemona japonica Miq. The absolute stereostructure of I has been determined by X-ray crystallographic analysis. Stemofoline (II) showed a much stronger activity than I against silkworm larvae (Bombyx moni L.) by oral administration.

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