Volatile Cucumis melo components: Identification of additional compounds and effects of storage conditions

Additional volatile compounds were isolated from muskmelon fruit by means of a water recycling apparatus, separated by GLC, and identified principally by MS and GLC retention data. Compounds reported for the first time as melon components are: n-hexanol, 1-octen-3-ol, cis-3-nonen-1-ol, n-butyl acetate, isobutyl acetate, 2-methylbutyl acetate, n-hexyl acetate, ethyl n-butyrate, ethyl 2-methylbutyrate, benzyl acetate, β-phenethyl acetate, and γ-phenylpropyl acetate. Muskmelon fruit stored frozen prior to steam distillation-extraction yielded an essence which, when compared with that obtained from freshly harvested fruit, contained considerably larger amounts of trans-2-nonenal, n-nonanol, cis-3-nonen-1-ol, cis-6-nonen-1-ol, and the methyl and ethyl esters of linoleic and linolenic acids. Marked decreases in the relative amounts of benzyl acetate, β-phenethyl acetate, and γ-phenylpropyl acetate resulted from freezing. All 21 compounds examined were present in the essences prepared from fresh, refrigerated, and frozen fruit.     

Substrate Specificity,Mode of Action,and of Inhibition by Organic Acids of Purified Acetylesterase from Sclerotinia Fungus

Acetylesterase (AcE) of Sclerotinia libertiana was purified approximately 1170-fold, and proved homogeneous by electrophoresis, ultracentrifugation and chromatography. The purified AcE hydrolyzed various acetyl esters in the following order; vinyl acetate, tri-acetin, n-butyl acetate, p-nitrophenylacetate, diacetin, ethylene glycol diacetate, monoacetin, ethyl acetate, acetylcholine, methyl acetate. It also had apparently a slight activity on tannic acid, benzoylcholine, methyl butyrate and acetic anhydride.

The mode of AcE reaction on these substrates could be divided into two types of group by Lineweaver-Burk plot, one forms the enzyme-substrate complex, ES, and the other, SES additionally combining substrate at a high substrate concentration.

From the inhibition experiment by organic acids, it was suggested that the neighbouring carboxyl groups of the di-, or tribasic acid such as citric, cis-aconitic, succinic, and maleic acid have a significance on inhibition of the AcE. Also, choline esterase inhibitor partially inhibited the activity on acetylcholine, and bivalent metal ion increased the activity on triacetin. Thus, the AcE was supposed to have a many adjacent sites of interaction with the substrate.     

Carboxylic Acids in Cultured Broth of Sporobolomyces odorus

Carboxylic acids found in the cultured broth of Sporobolomyces odorus AHU 3246 which produces γ-lactones as principles of the aromatic flavor, were analyzed. The concentrate of methylated acids was steam-distilled and in the residue, succinic acid, nonanedioic acid (azelaic acid), undecanedioic acid and 2-hydroxy-3-phenylpropionic acid (β-phenyllactic acid) were identified as their methyl esters by GLC and spectroscopic methods. Phthalic acid and its mono-n-butyl ester were also found, but these compounds were thought to arise from di-n-butyl phthalate, one of impurities of deionized water.     

Formation of Volatile Esters in Strawberries

Aliphatic alcohols including methyl, ethyl, isopropyl, npropyl, isobutyl, nbutyl, isoamyl, namyl and hexyl alcohol were converted to their acetate, propionate, nbutyrate, isovalerate and caproate esters during the incubation with strawberry fruit tissue. Formate, isobutyrate and n-valerate esters were formed when alcohols were incubated together with these fatty acids and strawberry.

Seventy esters were formed from various combinations of alcohols and acids by means of incubation with strawberry.

No ester formation was observed when strawberry was homogenized.     

Availability of Energy in Esters of Aliphatic Acids and Alcohols by Growing Chicks

Biological availability of 106 esters of alcohols and aliphatic mono-, di- and tri-carboxylic acids and diethylene glycol succinate was compared by the mini-test with chicks. Chicks can utilize methyl esters of saturated fatty acids of carbon chain from 10 to 14, ethyl esters of those from 9 to 12, propyl caprate, n-butyl esters of those from 8 to 12, n-amyl esters of those from 6 to 12, n-hexyl n-butyrate and i-vaterate, and n-octyl and n-decyl acetates. Only 3 dicarboxylates, i.e. di-octyl and di-lauryl succinates and di-methyl cis-cyclopropane-l,2-dicarboxylate, were available among the dicarboxylates tested. Availability of ethyl esters of succinic, fumaric and citric, acid was unexpectedly low.     

Studies on Leaf Oils of Citrus Species

Leaf oil samples of four Japanese citrus species were analysed by gas chromatography to determine the detailed composition of each leaf oil. The following components were identified: α-pinene, α-thujene, camphene, β-pinene, sabinene, β-myrcene, α-terpinene, limonene, β-phellandrene, trans-2-hexen-1-al, γ-terpinene, p-cymene, terpinolene, cis-2-penten-1-ol, n-hexyl alcohol, cis-3-hexen-1-ol, trans-2-hexen-1-ol, p-α-dimethylstyrene linalool, linalyl acetate, β-elemene, terpinen-4-ol, caryophyllene, humulene, α-terpineol, neryl acetate, geranyl acetate, β-selinene, geraniol and thymol. Most components were contained in common in leaf oils of the four citrus species, but relative contents of some of the components; such as γ-terpinene, linalyl acetate, and thymol differed from species to species. For example, γ-terpinene was the major component (33.8%) of Hassaku, whereas it was only a minor component in Daidai. Daidai is characterized by a very high content of linalyl acetate (35%) which is only a trace in the other three species. Kishu-mikan is characterized by a high content of thymol (15%).     

Efficient bioreduction of ethyl 4-chloro-3-oxobutanoate to (S)-4-chloro-3-hydrobutanoate by whole cells ofCandida magnoliae in water/n-butyl acetate two-phase system

The asymmetric biosynthesis of ethyl (S)-4-chloro-3-hydrobutanoate from ethyl 4-chloro-3-oxobutanoate was investigated by using whole cells ofCandida magnoliae JX120-3 without the addition of glucose dehydrogenase or NADP⁺/NADPH. In a one-phase system, the bioconversion yield was seriously affected on the addition of 12.1 g/L ethyl 4-chloro-3-oxobutanoate. In order to reduce this substrate inhibition, a water/n-butyl acetate two-phase system was developed, and the bioreduction conditions optimized with regard to the yield and product enantiometric excess value. The optimal conditions were as following: water ton-butyl acetate volume ratio of 1∶1, 4.0 g DCW/L active cells, 50 g/L glucose and 35°C. By adopting a dropwise substrate feeding strategy, high concentration of ethyl 4-chloro-3-oxobutanoate (60 g/L) could be asymmetrically reduced to ethyl (S)-4-chloro-3-hydrobutanoate with high yield (93.8%) and high enantiometric excess value (92.7%).     

The Odor and the Infrared Spectra of Furfuryl Sulfides

By using furfuryl mercaptan as the starting material, the following sulfides have been prepared: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-amyl, isoamyl, n-hexyl, n-octyl, n-decyl, allyl, prenyl (3-methyl-2-butenyl), benzyl, propargyl, β-hydroxyethyl furfuryl sulfides.

Most of these compounds showed grassy or spicy odor which is distinguishable from the roasted-coffee aroma of furfuryl mercaptan. The infrared spectra of furfuryl alcohol, furfuryl mercaptan and the furfuryl sulfides in carbon tetrachloride have also been compared to find the characteristic absorptions for furfuryl sulfides and a medium band has been detected at 1130 cm^?1, which could be useful in identifying furfuryl sulfide group.     

Synthesis and Biological Activity of Analogs of the Cecropia Juvenile Hormone with Different Alkyl Substituents at C-7 and C-11

Sixteen new Cecropia juvenile hormone (JH) analogs with different alkyl substituents at C–7 and C–11 were synthesized as stereoisomeric mixtures. The epoxides with n-propyl or n-butyl and methyl groups at C-11 and methyl or ethyl group at C-7 showed high JH activity on Bombyx mori L. Structure-activity relationship of the JH analogs was discussed.     

Studies on Abscisic Acid

Oxidation of methvl 2-trans-β-ionylideneacetate with X-bromosuccinimide afforded methyl 2-cis and trans-3′-hydroxy-β-ionylideneacetates. NaBH₄ reduction of methyl 2-cis-3′-keto-β-ionylideneacetate and ethyl 4′-keto-α-ionylideneacetate gave methyl 2-cis-3′-hydroxy-β-ionylideneacetate and ethyl 4′-hydroxy-α-ionyiideneacetate respectively. Further, methyl 4′-methoxy-epoxy-α-ionylideneacetate was prepared by epoxidation of methyl 4′-methoxy-α-ionylideneacetate. And then methyl 4′-hydroxy-l′, 2′-dihydro-β-ionylideneacetate was synthesized from ethyl 4-keto-α-cyclogeranate. Growth inhibitory activities of the above compounds on rich seedlings were examined.     

Biofiltration of paint solvent mixtures in two reactor types: overloading by hydrophobic components

Steady-state performance characteristics of a trickle bed reactor (TBR) and a biofilter (BF) in loading experiments with increasing toluene/xylenes inlet concentrations while maintaining a constant loading rate of hydrophilic components (methyl ethyl and methyl isobutyl ketones, acetone, and n-butyl acetate) of 4 g m⁻³ h⁻¹ were evaluated and compared, along with the systems’ dynamic responses. At the same combined substrate loading of 55 g m⁻³ h⁻¹ for both reactors, the TBR achieved more than 1.5 times higher overall removal efficiency (RE_W) than the BF. Increasing the loading rate of aromatics resulted in a gradual decrease of their REs. The degradation rates of acetone and n-butyl acetate were also inhibited at higher loads of aromatics, thus revealing a competition in cell catabolism. A step-drop in loading of aromatics resulted in an immediate increase of RE_W with variations in the TBR, while the new steady-state value in the BF took 6–7 h to achieve. The TBR consistently showed a greater performance than BF in removing toluene and xylenes. Increasing the loading rate of aromatics resulted in a gradual decrease of their REs. The degradation rates of acetone and n-butyl acetate were also lower at higher OL_AROM, revealing a competition in the cell catabolism. The results obtained are consistent with the proposed hypothesis of greater toxic effects under low water content, i.e., in the biofilter, caused by aromatic hydrocarbons in the presence of polar ketones and esters, which may improve the hydrocarbon partitioning into the aqueous phase.     

New Rapid Methods for Tissue Diagnosis

Two new methods applicable to the staining of fixed and fresh frozen tissue sections are presented herein. In addition certain improvements are suggested for the technic reported by Geschickter, Walker, Hjort and Moulton (1931). In brief the procedures are as follows:

The thionin eosinate method of Geschickter et al (1931). This procedure has been modified as follows:

A mixture of diethylene glycol, 40 parts, ethylene glycol, 40 parts, and grain alcohol, 20 parts is superior to ethylene glycol, 80 parts, and ethyl alcohol, 20 parts, as a solvent for the compound stain in that the staining is intensified.

Ethylene glycol monobutyl ether supplants diethylene glycol monobutyl ether because of its lower viscosity.

Ethyl phthalate replaces butyl phthalate on account of a more satisfactory viscosity.

The methyl green eosinate procedure is the same as the modified thionin eosinate method except for the following variations:

The staining time is increased to one minute.

Decolorization and washing are reduced to about 15 seconds.

The hematoxylin-eosin method. After cutting, the tissue sections are carried thru the following steps:

Unfold in water; transfer to formalin (4 to 40%) for at least 30 seconds; stain in hematoxylin (Harris) for 30 to 60 seconds; wash in water, 5 seconds; decolorize in 0.1% HC1 or saturated aqueous picric acid, 5 seconds; wash in water, S seconds; float in 0.5% ammonia, 5 to 10 seconds; wash in water, 5 seconds; stain in 5% aqueous eosin, 15 seconds¹; wash in water, 5 to 10 seconds; dehydrate in a mixture of diethylene glycol, 30 parts, and ethyl alcohol, 70 parts, 5 to 10 seconds; dehydrate in ethylene glycol monobutyl ether, 5 to 10 seconds; clear in ethyl phthalate, 5 to 10 seconds; float on a glass slide, blot with photographic lintless blotter, place a drop of neutral gum damar on the section, and cover with glass cover slip.     

Substrate Specificity of Regiospecific Desaturation of Aliphatic Compounds by a Mutant Rhodococcus Strain

Substrate specificity of cis-desaturation of alipahtic compounds by resting cells of a mutant, Rhodococcus sp. strain KSM-MT66, was examined. Among substrates tested, the rhodococcal cells were able to convert n-alkanes (C13-C19), 1-chloroalkanes (C16 and C18), ethyl fatty acids (C14-C17) and alkyl (C1-C4) esters of palmitic acid to their corresponding unsaturated products of cis configuration. The products from n-alkanes and 1-chloroalkanes had a double bond mainly at the 9th carbon from their terminal methyl groups, and the products from acyl fatty acids had a double bond mainly at the 6th carbon from their carbonyl carbons.     

The synthesis of isomeric 4-prolinylamines and 4,4′-diprolinylamines

Starting from the previously describedtert-butyl esters of 4-epimericN-benzyloxycarbonyl-4-hydroxyprolines andN-benzyloxycarbonyl-4-trans- and 4-cis-trifluoroacetaminoprolinetert-butyl esters, the corresponding uprotected 4-aminoprolines and a number of their partially protected derivatives were synthesized via the intermediate 4-O-mesyl and 4-azide derivatives. The reductive amination ofN-benzyloxycarbonyl-4-oxoprolinetert-butyl ester with ammonium acetate led toN-benzyloxycarbonyl-4-cis-4′-cis- and 4-cis-4′-trans-diprolinylamines. The¹H NMR and CD spectra of the synthesized compounds are described.     

Effects <Emphasis Type="Italic">per se</Emphasis> of Organic Solvents in the Cerebral Acetylcholinesterase of Rats

Acetylcholinesterase (AChE) was studied in different rat brain regions (cerebellum, hypothalamus, striatum, hippocampus and cortex) in the presence of different organic solvents normally used in the in vitro assay. The organic solvents used were acetone (C₃H₆O), acetonitrile (C₂H₃N), ethyl alcohol (C₂H₆O), isopropyl alcohol (C₃H₈O), methyl alcohol (CH₄O), tert-butyl alcohol (C₄H₁₀O) and dimethyl sulfoxide (DMSO, C₂H₆OS) ranging from 0.6 to 10%. Ethyl and methyl alcohol presented no effect on AChE activity at any of the concentrations and brain structures tested. In the hippocampus, isopropyl alcohol did not demonstrate a significant inhibitory effect, even at high concentrations. Tert-butyl alcohol presented an interesting result, increased AChE activity (P < .05) in the hypothalamus (1.8%), cortex (1.8 and 2.5) and striatum (1.2, 1.8 and 2.5%) and decreased activity at a concentration of 10% in the cortex (P < .05) and striatum (P < .01). Acetone and acetonitrile presented similar results, both significantly inhibiting AChE in all structures (5%, P < .05 and 10%, P < .01). DMSO exhibited a highly inhibitory effect at practically all concentrations tested (P < .01). In conclusion, for testing new compounds on AChE activity in vitro, methyl and ethyl alcohol may be the best organic solvent choice.     

Synthesis of symmetric and asymmetric diamides of citric acid and amino acids

Summary A convenient method for the synthesis of symmetric and asymmetric diamides of amino acids including DOPA and citric acid from 2-tert-butyl-1,3-di(N-hydroxysuccinimidyl)citrate and 1-tert-butyl-2,3-di(N-hydroxysuccinimidyl)citrate is described.Abbreviations AcOtBu tert-butyl acetate - i-Bu iso-butyl - tBu tert-butyl - Bzl benzyl - p-OH-Bzl p-hydroxybenzyl - m,p-(OH)₂-Bzl m,p-dihydroxybenzyl - DCCI dicyclohexylcarbodiimide - Et ethyl - Me methyl - Su succinimidyl - SuOH N-hydroxysuccinimide - Ph phenyl     

Catalytic Properties of Carbonyl Reductase from Rabbit Kidney for Acetohexamide and Its Analogs

Analogs submitted by ethyl, n-propyl, n-butyl, and isopropyl groups instead of methyl group adjacent to a ketone group of acetohexamide were synthesized and the structural requirements of carbonyl reductase from rabbit kidney for these analogs were kinetically examined. The hydrophobicities in straight-chain alkyl groups of acetohexamide analogs were found to play an important role in the catalytic activity and substrate-binding capacity of the enzyme. We propose the possibility that a hydrophobic pocket is located in the substrate-binding domain of the enzyme.     

Effects of environmental settings on MTBE removal for a mixed culture and its monoculture isolation

A mixed culture was utilized to evaluate methyl tert-butyl ether (MTBE) removal under various conditions and to isolate a MTBE-degrading pure culture. The results showed that high MTBE removal efficiencies can be reached even in the presence of other substrates. The biodegradation sequence of the target compounds by the mixed culture, in order of removal rate, was toluene, ethyl benzene, p-xylene, benzene, MTBE, ethyl ether, tert-amyl methyl ether, and ethyl tert-butyl ether. In addition, preincubation of the mixed cultures with benzene and toluene showed no negative effect on MTBE removal; on the contrary, it could even increase the degradation rate of MTBE. The kinetic behavior showed that the maximum specific growth rate and the saturation constant of the mixed culture degrading MTBE are 0.000778 h⁻¹ and 0.029 mg l⁻¹, respectively. However, a high MTBE concentration (60 mg l⁻¹) was slightly inhibiting to the growth of the mixed culture. The pure culture isolated from the enrichments in the bubble-air bioreactor showed better efficiency in MTBE removal than the mixed culture; whereas, tert-butyl alcohol was formed as a metabolic intermediate during the breakdown of MTBE.     

Synthesis of 3′-C-Phosphono Nucleosides from α,β-Unsaturated Lactone

Abstract

The reaction of 5-protected α,β-unsaturated γ-lactone 4 with trialkylphosphite gave 3′-C-dialkylphosphono-erythro lactone 5 in high yields. The lactone 5 was reduced with DIBAL to the corresponding lactol, which was converted to the acetate 6 by treatment with acetic anhydride in pyridine. The acetate 6 was coupled with silylated thymine in the presence of TMS-triflate and the resulting anomeric mixture of nucleotides could be separated chromatographically and after desilylation using TBAF in THF the 3′-C-dialkylphosphono nucleosides 7 and 8 were obtained.     

cis-trans Isomerization Products from S-(cis-1-Propenyl)-l-cysteine and Its Sulfoxide Irradiated in Aqueous Solutions

In connection with food-flavor deterioration accompanied by irradiation, the formation mechanism of the degradation products from S-(cis-1-propenyl)-l-cysteine (PeCS) and its sulfoxide (PeCSO) (isomers of the naturally-occurring lachrymatory precursors of onion) irradiated by γ-ray in oxygen-free aqueous solutions was investigated.

From the comparisons of mass-spectral fragmentations, gas-chromatographic retention time and IR spectra with reference compounds, the major volatile products from γ-irradiated PeCS were identified as n-propyl cis-1-propenyl sulfide, n-propyl trans-1-propenyl sulfide, cis, cis-di-1-propenyl sulfide and cis, trans-di-1-propenyl sulfide and those from γ -irradiated PeCSO were identified as di-1-propenyl sulfides (cis-cis and cis-trans). A new cis-trans isomerization mechanism of the 1-propenyl thiyl radicals was suggested and it was elucidated to give a mixture of about 33% cis- and 67% trans-1-propenyl thiyl radicals.