Improvement in the Stability and Enzymatic Activity of Pleurotus sapidus Lipoxygenase Dissolved in Natural Deep Eutectic Solvents (NADESs)

Natural deep eutectic solvents (NADESs) can serve as solvents for enzymes, are biodegradable, and have low toxicities. Eight NADESs with different hydrogen bond acceptors and donors were tested to improve the stability and activity of a lipoxygenase from Basidiomycete Pleurotus sapidus (LOXPSA). Betaine:sorbitol:water (1:1:3, BSorbW) and betaine:ethylene glycol (1:3, BEtGly) had the best impact on the peroxidation of linoleic acid and the side reaction of piperine to the vanilla-like scented compound piperonal. The yield of piperonal in NADESs increased by 43% in BSorbW and 40% in BEtGly compared to the control. The addition of BSorbW also enhanced the enzyme's stability at various temperatures and increased its activity during incubation at 60 °C. The demonstrated improvement in lipoxygenase activity and stability indicates versatile applications in industry, expanding the potential uses of the enzyme.

Production of natural colorants by liquid fermentation with Chlorociboria aeruginascens and Laetiporus sulphureus and prospective applications

The replacement of potentially hazardous synthetic dyes with natural dyes and pigments are of great interest for a sustainable economy. In order to obtain cost-efficient, environmentally friendly and competitive products, improvements in the cultivation and extraction of pigment-producing organisms and in dyeing processes are necessary. In our study, we were able to scale up the production of xylindein by Chlorociboria aeruginascens from 3 to 70 L bioreactor cultivations. We have identified important bioprocess parameters like low shear stress (150 rpm, tip speed <0.5 m/s) for optimal pigment yield (4.8 mg/L/d). Additionally, we have demonstrated the potential of laetiporic acid production by Laetiporus sulphureus in various cultivation systems and media, achieving dried biomass concentrations of almost 10 g/L with a 7 L bioreactor cultivation after 17 days. Extractions performed at 70°C and 15 min incubation time showed optimal results. To the best of our knowledge, we have described for the first time the use of this pigment in silk dyeing, which results in a brilliant hue that cannot easily be produced by other natural pigments.

Hydrolysis of chlorogenic acid in apple juice using a p-coumaryl esterase of Rhizoctonia solani

BACKGROUND

Apple juice is rich in polyphenolic compounds, especially in chlorogenic acid. A sour and bitter taste has been attributed to the compound. Chlorogenic acid in coffee powder was quickly hydrolysed by a p-coumaryl esterase of Rhizoctonia solani (RspCAE) at its optimal pH of 6.0. It was unknown, however, if RspCAE would also degrade chlorogenic acid under the strongly acidic conditions (pH 3.3) present in apple juice.

RESULTS

Treatment of apple juice with RspCAE led to a chlorogenic acid degradation from 53.38 ± 0.94 mg L^-1 to 21.02 ± 1.47 mg L^-1 . Simultaneously, the caffeic acid content increased from 6.72 ± 0.69 mg L^-1 to 19.33 ± 1.86 mg/L^-1 . The aroma profile of the enzymatically treated sample and a control sample differed in only one volatile. Vitispirane had a higher flavour dilution factor in the treated juice. Sensory analysis showed no significant difference in the taste profile ( p < 0.05).

CONCLUSION

These results demonstrated a high stability and substrate specificity of RspCAE. An increase in caffeic acid and a concurrent decrease in chlorogenic acid concentration may exert a beneficial effect on human health. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Highly Variable Pharmacokinetics of Tyramine in Humans and Polymorphisms in OCT1, CYP2D6, and MAO-A

Tyramine, formed by the decarboxylation of tyrosine, is a natural constituent of numerous food products. As an indirect sympathomimetic, it can have potentially dangerous hypertensive effects. In vitro data indicated that the pharmacokinetics of tyramine possibly depend on the organic cation transporter OCT1 genotype and on the CYP2D6 genotype. Since tyramine is a prototypic substrate of monoamine oxidase A (MAO-A), genetic polymorphisms in MAO-A may also be relevant. The aims of this study were to identify to what extent the interindividual variation in pharmacokinetics and pharmacodynamics of tyramine is determined by genetic polymorphisms in OCT1, CYP2D6, and MAO-A. Beyond that, we wanted to evaluate tyramine as probe drug for the in vivo activity of MAO-A and OCT1. Therefore, the pharmacokinetics, pharmacodynamics, and pharmacogenetics of tyramine were studied in 88 healthy volunteers after oral administration of a 400 mg dose. We observed a strong interindividual variation in systemic tyramine exposure, with a mean AUC of 3.74 min*µg/ml and a high mean CL/F ratio of 107 l/min. On average, as much as 76.8% of the dose was recovered in urine in form of the MAO-catalysed metabolite 4-hydroxyphenylacetic acid (4-HPAA), confirming that oxidative deamination by MAO-A is the quantitatively most relevant metabolic pathway. Systemic exposure of 4-HPAA varied only up to 3-fold, indicating no strong heritable variation in peripheral MAO-A activity. Systolic blood pressure increased by more than 10 mmHg in 71% of the volunteers and correlated strongly with systemic tyramine concentration. In less than 10% of participants, individually variable blood pressure peaks by >40 mmHg above baseline were observed at tyramine concentrations of >60 µg/l. Unexpectedly, the functionally relevant polymorphisms in OCT1 and CYP2D6, including the CYP2D6 poor and ultra-rapid metaboliser genotypes, did not significantly affect tyramine pharmacokinetics or pharmacodynamics. Also, the MOA-A genotypes, which had been associated in several earlier studies with neuropsychiatric phenotypes, had no significant effects on tyramine pharmacokinetics or its metabolism to 4-HPAA. Thus, variation in tyramine pharmacokinetics and pharmacodynamics is not explained by obvious genomic variation, and human tyramine metabolism did not indicate the existence of ultra-low or -high MAO-A activity.

Factors limiting the enzymatic hydrolysis of wheat gluten

The enzymatic hydrolysis of wheat gluten for the production of seasonings using mixtures of endo- and exopeptidases results in yields typically below 40%. Possible limiting parameters, such as an increasing product inhibition, autopeptidolysis of the enzymes, and lack of cleavage sites, were studied using novel peptidases from Flammulina velutipes or the commercial Flavourzyme preparation. Seven intermittent electrodialysis steps (10 g/L gluten and 10 kaU/mL) for the in situ removal of amino acids minimized the product inhibition. During 16 h, hydrolysis progressed nearly linearly. Compared to the batch control, a 3-fold yield of amino acids released was obtained indicating that an integrated product removal alleviates the problem of product inhibition. Autopeptidolysis, as shown using sodium dodecyl sulfate polyacrylamide gel electrophoresis and enzyme activity assays, was suppressed with increasing concentrations of competing gluten substrate. Peptidases of F. velutipes showed product inhibition only, whereas a combined effect of product inhibition and lack of cleavage sites was observed for Flavourzyme.

Hydrolysis of wheat gluten by combining peptidases of Flammulina velutipes and electrodialysis

Wheat gluten hydrolysis, used to generate seasonings, was studied using peptidases from Flammulina velutipes or commercial Flavourzyme. L-amino acids were added in a range from 0.5 to 75.0 mM, and L-isoleucine, L-leucine, L-valine, and L-phenylalanine were identified as the strongest inhibitors for both enzyme mixtures. L-serine inhibited Flammulina velutipes peptidases only, while L-histidine and L-glutamine inhibited Flavourzyme peptidases only. To reduce product inhibition by released L-amino acids, electrodialysis was explored. An increase of the degree of hydrolysis of up to 60% for Flammulina velutipes peptidases and 31% for Flavourzyme compared to that for the best control batch was observed after applying an electrodialysis unit equipped with an ultrafiltration membrane for two times 1 h during the 20 h of hydrolysis. The total transfer of free L-amino acids into the concentrate reached 25-30% per hour. Peptides passed the membrane less easily, although the nominal cutoff was 4 kDa.

Antioxidants in food: mere myth or magic medicine?

The powerful action of antioxidants in preventing premature lipid oxidation in food suggests that the same compounds, when consumed with the daily diet, could unfold antioxidative/anti-aging effects in the human body. Therefore, it has been hypothesized that antioxidants are helpful in preventing various diseases. More detailed chemical and physiological examination of antioxidants shows, however, that the extrapolation of in vitro data to in vivo behavior may be misleading. Indeed, such a procedure fails to take into account the mismatch between most in vitro models (e.g., cell cultures) and in vivo systems. For example, the physiological relevance of pro-oxidative and other physiological activities of antioxidants have been largely underestimated. Actually, contrary to the antioxidant hypothesis, clinical trials testing the health benefits of dietary antioxidants have reported rather mixed or negative results. Many clinical studies have not taken into account the nutrikinetic and nutridynamic nature of antioxidants. Further, oxidative stress is not only an inevitable event in a healthy human cell, but responsible for the functioning of vital metabolic processes, such as insulin signaling and erythropoietin production. In the light of recent physiological studies it appears more advisable to maintain the delicate redox balance of the cell than to interfere with the antioxidant homeostasis by a non-physiological, excessive exogenous supply of antioxidants in healthy humans.

PsoP1, a milk-clotting aspartic peptidase from the basidiomycete fungus Piptoporus soloniensis

The first enzyme of the basidiomycete Piptoporus soloniensis, a peptidase (PsoP1), was characterized after isolation from submerged cultures, purification by fractional precipitation, and preparative native-polyarylamide gel electrophoresis (PAGE). The native molecular mass of PsoP1 was 38 kDa with an isoelectric point of 3.9. Similar to chymosin from milk calves, PsoP1 showed a maximum milk-clotting activity (MCA) at 35-40 °C and was most stable at pH 6 and below 40 °C. The complete inhibition by pepstatin A identified this enzyme as an aspartic peptidase. Electrospray ionization-tandem MS showed an amino acid partial sequence that was more homologous to mammalian milk clotting peptidases than to the chymosin substitute from a fungal species, such as the Zygomycete Mucor miehei. According to sodium dodecyl sulfate-PAGE patterns, the peptidase cleaved κ-casein in a way similar to chymosin and hydrolyzed β-casein slowly, as it would be expected from an efficient chymosin substitute.

Genetic dissection of scent metabolic profiles in diploid rose populations

The scent of flowers is a very important trait in ornamental roses in terms of both quantity and quality. In cut roses, scented varieties are a rare exception. Although metabolic profiling has identified more than 500 scent volatiles from rose flowers so far, nothing is known about the inheritance of scent in roses. Therefore, we analysed scent volatiles and molecular markers in diploid segregating populations. We resolved the patterns of inheritance of three volatiles (nerol, neryl acetate and geranyl acetate) into single Mendelian traits, and we mapped these as single or oligogenic traits in the rose genome. Three other volatiles (geraniol, beta-citronellol and 2-phenylethanol) displayed quantitative variation in the progeny, and we mapped a total of six QTLs influencing the amounts of these volatiles onto the rose marker map. Because we included known scent related genes and newly generated ESTs for scent volatiles as markers, we were able to link scent related QTLs with putative candidate genes. Our results serve as a starting point for both more detailed analyses of complex scent biosynthetic pathways and the development of markers for marker-assisted breeding of scented rose varieties.

Improved monoterpene biotransformation with Penicillium sp. by use of a closed gas loop bioreactor

A closed gas loop bioprocess was developed to improve fungal biotransformation of monoterpenes. By circulating monoterpene-saturated process gas, the evaporative loss of the volatile precursor from the medium during the biotransformation was avoided. Penicillium solitum, isolated from kiwi, turned out to be highly tolerant towards monoterpenes and to convert alpha-pinene to a range of products including verbenone, a valuable aroma compound. The gas loop was mandatory to reproduce the production of 35 mg L(-1) verbenone obtained in shake flasks and also in the bioreactor. Penicillium digitatum DSM 62840 regioselectively converted (+)-limonene to the aroma compound alpha-terpineol, but shake flask cultures revealed a pronounced growth inhibition when initial concentrations exceeded 1.9 mM. In the bioreactor, toxic effects on P. digitatum during biotransformation were alleviated by starting a sequential feeding of non-toxic limonene portions after a preceding growth phase. Closing the precursor-saturated gas loop during the biotransformation allowed for an additional replenishment of limonene via the gas phase. The gas loop system led to a maximum alpha-terpineol concentration of 1,009 mg L(-1) and an average productivity of 8-9 mg L(-1) h(-1) which represents a doubling of the respective values previously reported. Furthermore, a molar conversion yield of up to 63% was achieved.

Enzyme immunoassay of testosterone, 17beta-estradiol, and progesterone in perspiration and urine of preadolescents and young adults: exceptional levels in men's axillary perspiration

Enzyme immunoassays for testosterone, 17beta-estradiol, and progesterone were validated for human facial and axillary perspiration and compared to levels in urine. In study 1, these assays were applied to samples from preadolescent girls and boys and young women and men. Men's axillary perspiration contained substantially higher levels of steroids than seen in other substrates from men or in any sample from women, boys, and girls. Male axillary steroid levels were very variable across individuals, and on average they exceeded levels in facial perspiration by 90-fold for testosterone and 45-fold for estradiol. Men's urinary testosterone also exceeded urinary levels of the other subjects. In study 2, axillary perspiration, urine, and saliva were collected from young men. Substantial axillary levels of testosterone and estradiol were again observed. Correlations of the same hormone among the different substrates were generally very low, except for a small correlation between estradiol levels measured in axillary perspiration and urine in study 2. High unconjugated steroid content in men's axillary excretions could, if absorbed by women during intimacy, be implicated in pheromonal activity.

Degradation of α-pinene oxide and [2H7]-2,5,6-trimethyl-hept-(2E)-enoic acid by Pseudomonas fluorescens NCIMB 11761

When submerged cultured Pseudomonas fluorescens NCIMB 11761 was fed-batch supplemented with alpha-pinene oxide, a rapid formation of 2,6-dimethyl-5-methylene-hept-(2Z)-enal (I) (isonovalal) was observed. Biotransformation and isomerisation of (I) to the (2E)-isomer (II) (novalal) were enhanced by Lewatit OC 1064, a macroporous polystyrene adsorbent. Accelerated isomerisation in the presence of an amino donor (glycine) at pH 7.3 pointed to a merely chemical mechanism. A maximum yield of 48 g of aldehydesl(-1) was achieved, but quantitative analysis of the volatile fraction showed that the molar conversion of the pinene oxide substrate reached no more than 67%. To fill this gap of the mass balance, the acidic fraction was isolated. It contained several compounds which suggested a beta-oxidation-like catabolism starting from 2,6-dimethyl-5-methylene-hept-(2E)-enoic acid (III) (novalic acid). Using [2H7]-2,5,6-dimethyl-hept-(2E)-enoic acid as a conversion substrate and gas chromatography coupled to atomic emission detection and mass spectrometry a degradation pathway via labelled 3,4-dimethylpentenoic and methylpropanoic acids was evidenced. This pathway may play a predominant role in isoprenoid degradation by soil bacteria.

GC/MS analysis of some bioactive constituents from Carthamus lanatus L

Sterols, triterpenes, volatiles, polar and other constituents in aerial parts of Carthamus lanatus were analyzed by gas chromatography-mass spectrometry. Over 90 compounds were identified most of them new for the species. Sitosterol and stigmasterol were the most abundant of 10 sterols identified in the sterol fraction. Taraxasterol, alpha- and beta-amyrine prevailed in the triterpene fraction. Volatiles, sterols and a fraction of the dichloromethane extract showed strong cytotoxicity (Artemia salina assay).

Cleavage of beta,beta-carotene to flavor compounds by fungi

More than 50 filamentous fungi and yeasts, known for de novo synthesis or biotransformation of mono-, sesqui-, tri-, or tetraterpenes, were screened for their ability to cleave beta,beta-carotene to flavor compounds. Ten strains discolored a beta,beta-carotene-containing growth agar, indicating efficient degradation of beta,beta-carotene. Dihydroactinidiolide was formed as the sole conversion product of beta,beta-carotene in submerged cultures of Ganoderma applanatum, Hypomyces odoratus, Kuehneromyces mutabilis, and Trametes suaveolens. When mycelium-free culture supernatants from five species were applied for the conversions, nearly complete degradation of beta,beta-carotene was observed after 12 h. Carotenoid-derived volatile products were detected in the media of Ischnoderma benzoinum, Marasmius scorodonius, and Trametes versicolor. beta-Ionone proved to be the main metabolite in each case, whereas beta-cyclocitral, dihydroactinidiolide, and 2-hydroxy-2,6,6-trimethylcyclohexanone were formed in minor quantities. Using a photometric bleaching test, the beta,beta-carotene cleaving enzyme activities of M. scorodonius were partially characterized.

Chemoenzymatic synthesis of aroma active 5,6-dihydro- and tetrahydropyrazines from aliphatic acyloins produced by baker's yeast

Twenty-five acyloins were generated by biotransformation of aliphatic aldehydes and 2-ketocarboxylic acids using whole cells of baker's yeast as catalyst. Six of these acyloins were synthesized and tentatively characterized for the first time. Subsequent chemical reaction with 1,2-propanediamine under mild conditions resulted in the formation of thirteen 5,6-dihydropyrazines and six tetrahydropyrazines. Their odor qualities were evaluated, and their odor thresholds were estimated. Among these pyrazine derivatives, 2-ethyl-3,5-dimethyl-5,6-dihydropyrazine (roasted, nutty, 0.002 ng/L air), 2,3-diethyl-5-methyl-5,6-dihydropyrazine (roasted, 0.004 ng/L air), and 2-ethyl-3,5-dimethyltetrahydropyrazine (bread crustlike, 1.9 ng/L air) were the most intensive-smelling aroma active compounds.

A labeling study to elucidate the biosynthesis of 4-(4-hydroxyphenyl)-butan-2-one (raspberry ketone) by Nidula niveo-tomentosa

Submerged cells of the basidiomycete Nidula niveo-tomentosa, a microbial producer of 4-(4-hydroxyphenyl)-butan-2-one, were supplemented with (13)C-labeled L-phenylalanines and with [1-(13)C]glucose. Labeled transformation products were detected by a novel method of analyzing stable isotope-labeled metabolites, gas chromatography (GC) coupled to an atomic emission detector, and by GC-mass spectrometry. A benzoate moiety was side chain elongated according to the poly-beta-keto scheme. The presence of an acetyl coenzyme A-carboxylase inhibitor shifted the spectrum of products to benzyl compounds. Hence, the fungal pathway differs from the one established for plant tissues.

Raspberry ketone from submerged cultured cells of the basidiomycete Nidula niveo-tomentosa

The basidiomycete Nidula niveo-tomentosa produced 4-(4-hydroxyphenyl)-butan-2-one (raspberry ketone), one of the character impact components of raspberry flavor, and its corresponding alcohol. A systematic attempt was made to improve the productivity of this fungus. Variation of nutrient medium composition, precursor amount, time of supplementation, and cultivation period yielded a 50-fold increase in metabolite concentrations. Raspberry ketone and alcohol were easily isolated from the culture medium by solvent extraction. Glycosidically bound forms or accumulation of raspberry compounds in fungal cells were not detected. This microbial process offers an alternative for the production of natural raspberry flavor.

Phenyl propenoic side chain degradation of ferulic acid by Pycnoporus cinnabarinus - elucidation of metabolic pathways using [5-2H]-ferulic acid

The white-rot fungus Pycnoporous cinnabarinus (DMS-1184) was submerged cultured for 22 days under controlled conditions in a bioreactor. After 6, 9, and 15 days of culture the growth medium was supplemented with [5-2H]-labelled ferulic acid (I). The major phenolic compounds identified labelled were four lignans, the methyl esters of ferulic (I) and vanillic acid (VIII), (E)-coniferyl aldehyde (II), (E)-coniferyl alcohol (III), vanillic acid (VIII), vanillin (IX) and vanillyl alcohol (X). The detection of considerable amounts of labelled 4-hydroxy-3-methoxyacetophenone (VII) in the late growth phase suggested the increasing formation and decarboxylation of free 4-hydroxy-3-methoxybenzoylacetic acid (VI) and, thus, a beta-oxidation-like degradation of ferulic acid (I) or its methyl ester to vanillic acid (VIII). 4-Hydroxy-3-methoxybenzoylacetic acid methyl ester (VI) and 3-hydroxy-(4-hydroxy-3-methoxyphenyl)-propanoic acid methyl ester (V) were synthesised and then identified as metabolites in the culture medium. The fungal degradation of the phenyl propenoic side chain of ferulic acid (I), a principal key step of lignin decomposition, appeared to proceed analogous to fatty acids.

Intelligent use of NSAIDs--where do we stand?

Non-steroidal anti-inflammatory drugs (NSAIDs) are drugs commonly prescribed for a variety of medical conditions. They are potent pharmacological agents efficacious for inflammatory conditions, but have significant gastrointestinal (GI), renal and haematological toxicity that must not be taken lightly. The newer, more cyclooxygenase-(COX)-2-selective NSAIDs, have no effects on platelet function and little GI toxicity, but do have renal physiological effects. The superiority of one NSAID over another has not been clinically demonstrated in musculoskeletal conditions, nor has the efficacy of NSAIDs in non-inflammatory rheumatic conditions been shown to be better than that of simple analgesics. NSAIDs are indicated for primary therapy of inflammatory rheumatic diseases and the more selective COX-2 agents should be employed as first choice when economically feasible. NSAIDs should not be used indiscriminately for non-inflammatory osteoarthritis or musculoskeletal injuries, particularly in the elderly patient, in whom alternative, less toxic therapy should be sought.

Generation of odorous acyloins by yeast pyruvate decarboxylases and their occurrence in sherry and soy sauce

Volatile acyloins (alpha-hydroxy ketones) were obtained by condensing either aldehydes with pyruvate or 2-keto acids with acetaldehyde in a reaction catalyzed by yeast pyruvate decarboxylases (EC 4.1.1.1). Odor qualities and threshold values of 34 acyloins were evaluated, and 23 of them possessed distinct flavor properties. Sherry and soy sauce flavors were analyzed: 2-hydroxy-3-pentanone and 3-hydroxy-2-pentanone were identified in soy sauce for the first time; these and 2-hydroxy-5-methyl-3-hexanone and 3-hydroxy-1-phenyl-2-butanone were isolated from sherry for the first time. The biocatalytic efficiencies of crude pyruvate decarboxylase preparations from Zygosaccharomyces bisporus, Saccharomyces cerevisiae, Kluyveromyces lactis, and Kluyveromyces marxianus were compared. Product yields comparable to those of conversions with purified pyruvate decarboxylase demonstrated the suitability of crude enzyme extracts as cost-effective biocatalysts in acyloin formation. Conversion rates of >50% showed that the potential of this type of enzyme to catalyze the formation of aliphatic acyloins has been underestimated before.

A comparative study on the disintegration of filamentous fungi

Different methods for cell disintegration were tested for their efficacy on filamentous fungi, including percussion grinding, homogenization using an Ultra-Turrax, chemical treatment and lyophylization. The release of protein from Ganoderma applanatum and Pycnoporus cinnabarinus and the activity of cytoplasmatic glucose-6-phosphate dehydrogenase in the crude extracts were monitored to determine the efficiency of each disintegration technique used. Fungal cells proved to be particularly resistant towards some disintegration methods commonly used for yeasts and bacteria. Best results were obtained using a percussion grinder, if necessary, in combination with an Ultra-Turrax pretreatment.

Purification, characterisation and cDNA sequencing of pyruvate decarboxylase from Zygosaccharomyces bisporus

Cells of the wild-type yeast strain Zygosaccharomyces bisporus CBS 702 form alpha-hydroxy ketones from aromatic amino acid precursors during fermentation. Pyruvate decarboxylase (PDC, E.C. 4.1.1.1), the key enzyme of this biotransformation catalysing the non-oxidative decarboxylation of pyruvate and other 2-oxo-acids, was purified and characterised. The active enzyme is homotetrameric (alpha4) with a molecular mass of about 244 kDa. Activation of PDC by its substrate pyruvate results in a sigmoidal dependence of the reaction rate from substrate concentration (apparent Km value 1.73 mM; Hill coefficient 2.10). A cDNA library was screened using a PCR-based procedure, and a 1856 bp cDNA of PDC was identified and sequenced. The cDNA encodes a polypeptide of 563 amino acid residues (monomeric unit). Sequence alignments demonstrate high homologies (> 80%) to PDC genes from Saccharomyces cerevisiae, Kluyveromyces lactis and Kluyveromyces marxianus.

Effects of R-(+)-limonene on submerged cultures of the terpene transforming basidiomycete Pleurotus sapidus

The biotransformation of limonene by the basidiomycete Pleurotus sapidus yielded cis/trans-carveol and carvone as the main products. The transformation period was extended from 4 days after direct addition to 12 days by gas phase addition of the substrate. After 2 days of transformation, 97% of the substrate had accumulated in the mycelium, while only 3% were present in the culture medium. Substrate toxicity led to a decrease of dry matter. Adaptation of the precultures with small amounts of substrate doubled the concentration of carveol and increased the concentration of carvone by a factor of 3-4. Total product concentrations of > 100 mg l-1 were reached.

Biotransformation of citronellol by the basidiomycete Cystoderma carcharias in an aerated-membrane bioreactor

The basidiomycete Cystoderma carcharias transformed citronellol into 3,7-dimethyl-1,6,7-octanetriol as the main product. 3,7-Dimethyl-6,7-epoxy-1-octanol was identified as important intermediary product of the biotransformation, and the allylic diols 2,6-dimethyl-2-octene-1,8-diol, 3,7-dimethyl-5-octene-1,7-diol and 3,7-dimethyl-7-octene-1,6-diol were found to be minor products. Microbial formation of rose oxide, a flavour-impact component, was observed for the first time. The formation of the main products was inhibited by 70% after addition of 0.1 mmol l-1 cytochrome monooxygenase inhibitors. Formation of 3,7-dimethyl-1,6,7-octanetriol was effective in a bioreactor with aeration over a coil of a hydrophobic microporous polypropene capillary membrane. Production rates of up to 150 mg l-1 day-1 were reached and led to a product concentration of 866 mg l-1 (conversion rate: 52%). The total loss of the added volatile substrate via the exhaust air was 4.5% when this aeration method was used.

Biotechnological production of flavours and fragrances

The biotechnological generation of natural aroma compounds is rapidly expanding. Aroma chemicals, such as vanillin, benzaldehyde (bitter almond, cherry) and 4-(R)-decanolide (fruity-fatty) are marketed on a scale of several thousand tons per year. Their possible production by single-step biotransformations, bioconversions and de novo synthesis using microorganisms, plant cells or isolated enzymes is shown. The perspectives of bioprocesses for the oxifunctionalisation of lower terpenes by genetically modified organisms and economic aspects are discussed.

Analysis of oxylipins by high-performance liquid chromatography with evaporative light-scattering detection and particle beam-mass spectrometry

The metabolism of 13S-hydroperoxy-9Z,11E,15Z-octadecatrienoic acid was investigated in a crude enzyme extract from mung bean seedlings (Phaseolus radiatus L.). Hydroperoxide-metabolizing activity was mainly due to a hydroperoxide lyase and, to a lesser extent, to an allene oxide synthase and a peroxygenase. Oxylipins originating from hydrolysis and cyclization of the allene oxide synthase product 12,13-epoxy-9Z,11,15Z-octadecatrienoic acid and from peroxygenase catalysis were identified by high-performance liquid chromatography (HPLC) particle beam-mass spectrometry (PB-MS) and quantified by normal-phase HPLC with an evaporative light-scattering detector (ELSD). An advantage of this methodology was the possibility to avoid extensive derivatization procedures commonly used for the gas chromatographic analysis of oxylipins. Owing to a comparable sample inlet system, the ELSD served an important analytical pilot function for the PB-MS: Qualitatively identical chromatographic patterns were obtained with both detection systems. The HPLC system enabled the separation of methyl 12-oxo-phytodienoate, methyl 11-hydroxy-12-oxo-9Z,15Z-octadecadienoate, methyl 12-oxo-13-hydroxy-9Z,15Z-octadecadienoate, methyl 9-hydroxy-12-oxo-10E,15Z-octadecadienoate, methyl 13-hydroxy-9Z,11E,15Z-octadecatrienoate, methyl 15,16-epoxy-13-hydroxy-9Z,11E-octadecadienoate, and methyl 13-hydroperoxy-9Z,11E,15Z-octadecatrienoate on a Lichrospher DIOL column within 33 min. Compared with a diode array detector, the ELSD proved to be more sensitive, in the case of methyl 12-oxo-13-hydroxy-9Z, 15Z-octadecadienoate by a factor of about 15. In addition, volatile metabolites were analyzed by capillary gas chromatography. The yield of the hydroperoxide lyase product 2E-hexenal was 49%, whereas the sum of oxylipins reached about 15%.

Geosmin and Related Volatiles in Bioreactor-Cultured Streptomyces citreus CBS 109.60

Streptomyces citreus CBS 109.60 produced geosmin and a complex pattern of other volatile compounds during cultivation in a 2.5-liter laboratory bioreactor. Volatiles were isolated from disrupted cells, from the culture medium, and from the waste air of the bioreactor by adsorption on Lewatit OC 1064MD. Quantitative and qualitative analyses were carried out using capillary gas chromatography and coupled gas chromatography-mass spectroscopy. S. citreus produced 56 volatile compounds, which were mainly terpenoids but also included aliphatic ketones, alcohols, esters, pyrazines, furan(on)es, and aromatic types during the growth phase. The major components were geosmin and a germacradienol. A biosynthetic pathway for geosmin including eudesmanolides is proposed.

Separation and characterisation of bovine histone H1 subtypes by combined ion-exchange and reversed-phase chromatography and mass spectrometry

In order to separate and identify histone H1 subtypes from calf thymus we used both electrospray mass spectrometry (ES-MS) and matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) after a three-step chromatographic procedure consisting of reversed-phase high-performance liquid chromatography (RP-HPLC), size-exclusion chromatography (SEC) and ion-exchange chromatography (IEC). Under the RP-HPLC conditions described, we obtained two baseline-separated H1-fractions which were characterised by MALDI-TOF-MS. The determined masses ranged from 22,850 to 22,590 for the first fraction and from 22,070 to 21,250 for the second fraction. Further, it was shown that the first fraction contained at least four and the second one at least five subtypes of the histone class H1. Four homogeneous pure H1 subtypes were obtained by a combination of IEC followed by SEC and RP-HPLC. The molecular masses of these four subtypes determined by ES-MS were 22,606, 22,761, 21,347 and 21,263. We obtained six additional molecular masses of histone H1 subtypes from three heterogeneous fractions, namely 22,066, 21,802, 20,586 and 19,817 by ES-MS and 22,800 and 22,675 by MALDI-TOF-MS. The retention times of these fractions and the molecular masses were in agreement with the data obtained from RP-HPLC fractions by MALDI-TOF-MS.

Multimedia medical case authorship and simulator program

For the last several years, third and fourth year medical students rotating on the rheumatology/immunology service at the University of North Carolina School of Medicine have been using a laptop computer as a teaching adjunct to their formal training in rheumatology. The laptop contains diagnostic programs, reference management and clinical note generation facilities, remote medline access, and most recently, multimedia case simulations. These simulations have been created by the use of a case authoring and simulation system which is presented in this demonstration. The program is divided into simulator and designer modules and uses graphics and sound to portray such data as physical examination findings, blood smears, radiographs, heart sounds, etc. The simulator module includes diagnostic sections with feedback to the student as well as robust patient management trees with an occasional circuitous route for patient outcome. The student receives a numerical score based on deviations from the correct path and optimal cost as designated by the case designer. The system simulates complete management of a patient from the first encounter until treatment is complete. During each encounter, a student obtains the patient's history, physical examination findings, orders tests and reviews their results, makes a differential diagnosis, and treats the patient. The patient's progress and further treatment options at any time are dependent on the treatment option selected by the student at an earlier stage. Students are given the costs of ancillary tests and hospitalization before they order them. Words or phrases can be marked as hypertext and the student can get more information about the marked words by a mouse click. The designer interface of the program creates the clinical case by prompts and requests for information from the designer who needs no programming skills. The designer is almost always an expert faculty member who bases the simulated case on a real patient. Default and normal values for clinical findings and tests facilitate the case design. Graphics and sound files are easily incorporated into any historical, physical examination or test window. Management trees are automatically generated during the case design and the author is able to rapidly change to a new management scene for editing with a mouse click. Optimal critical path to correct cost effective diagnoses and treatment is designated and used as the standard to which the students' choices are compared. The software runs on PC's with 386 or better processors and is based in either Windows or OS/2 operating environments. The display can be VGA or SVGA, color or monochrome. Sound is played from 8 or 16 bit sound files. It can be readily extrapolated to any clinical medical specialty in the medical school or postgraduate curricula. The capabilities of this system to create unlimited, branched management and multiple clinical scenarios combined with the ease of authorship make this program unique and an excellent teaching tool.

Chemical phosphorylation of the peptides GGXA (X = S, T, Y): an evaluation of different chemical approaches

An evaluation was made of the two methods most commonly used for phosphorylation of hydroxyamino acids in peptides, i.e. the tetrazole-catalysed phosphitylation by di-tert-butyl-N,N-diethylphosphoramidite followed by oxidation and the phosphorylation by dibenzylphosphochloridate. As model system the sequence GGXA (X = S, T, Y) was used which represents a random-coil sequence avoiding the influence on the reaction kinetics of secondary structure formation. In the case of serine- and threonine-containing peptides, both synthetic methods gave comparable yields of the desired phosphopeptides. The phosphorylation of tyrosine was achieved more favorably via the phosphoramidite method. However, phosphotyrosine peptides are most easily obtained by peptide synthesis using Fmoc-Tyr(PO3Me2)OH as building block. The dibenzylphosphochloridate method yields the expected phosphopeptides as the only peptide derivative and in addition, a great number of unidentified by-products which can be removed by ion-exchange chromatography. The phosphoramidite method consistently resulted in three peptide derivatives, i.e. the desired phosphopeptide, the phosphitylated peptide and a bridged derivative with two GGXA fragments linked through a phosphodiester bridge. The derivatives were characterised by RP and ion-exchange chromatography, 31P- and 1H-NMR spectroscopy, and ion-spray and electrospray mass spectrometry. Interestingly, even these mild ionisation techniques resulted in partial fragmentation. The observed fragmentation pathways seem to be a diagnostic tool for the identification of phosphorylation sites in peptides. Both the phosphorylated serine and threonine peptide lost phosphoric acid (98 mass units), the tyrosine peptide lost phenyl phosphate (174 mass units).(ABSTRACT TRUNCATED AT 250 WORDS)

Report on the clinical workstation and clinical data repository utilization at UNC Hospitals

On December 1, 1993, we implemented version 2.1 of the Clinical Workstation-Clinical Data Repository application in the Ambulatory Care Center. This version of the workstation allowed access of laboratory data from the clinical data repository that had been populated by a real-time HL7 interface between the Clinical Data Repository and the Laboratory Information System. This implementation completed a major part of the Clinical Workstation project. Also in December, we implemented a security system that records the date and time, user logon code, clinical workstation functions used, and the patient medical record number on whom data were displayed. In addition to the security function, this system has proven to be a valuable tool in evaluating the utilization of the clinical workstation and is the source of the data presented in this paper.

Progress report on the clinical workstation and clinical data repository at UNC Hospitals

In 1991, we demonstrated a prototype version of the Clinical Workstation at SCAMC. At the present time 48 workstations have been implemented in the ambulatory care areas of the Hospital. We describe the present functionality of the workstation and the work done to date on the clinical data repository.

Comparison of azathioprine, methotrexate, and the combination of both in the treatment of rheumatoid arthritis. A controlled clinical trial

OBJECTIVE

To compare the relative safety and efficacy of azathioprine (AZA), methotrexate (MTX), and the combination of both in the treatment of active rheumatoid arthritis (RA).

METHODS

Two hundred twelve patients with active RA were entered into a 24-week prospective, controlled, double-blind, multicenter trial and were randomly assigned to 1 of 3 treatment groups.

RESULTS

One hundred fifty-eight patients finished 24 weeks of the study. There were no remissions seen but response rates were greater than 30% for all outcome measures. Combination therapy was not statistically superior to MTX therapy alone, but both combination therapy and MTX alone were superior to AZA alone when patients were analyzed by intent-to-treat and with withdrawals treated as therapy failures. If only patients who continued taking the therapy were analyzed, the mean improvement was greater for AZA therapy than for MTX, while the combination remained the most active. Adverse effects on the gastrointestinal tract and elevations of liver enzyme levels were the most frequent causes for discontinuations.

CONCLUSION

Both combination therapy and MTX alone were superior to therapy with AZA alone for active RA but were not statistically different in their effect on outcome assessment.

Making the transition from information systems of the 1970s to medical information systems of the 1990s: the role of the physician's workstation

Many hospitals today have implemented widely disparate information systems on mainframe and mini-computer hardware. The advent of network technology in hospitals has made it possible to access information in these systems. Unfortunately, the user interfaces to applications on these systems are unique and difficult to learn, which makes them unsuitable for use by clinical services. In this paper we describe the development of a Physician's Workstation which integrates information from multiple existing information systems and discuss how the workstation makes it possible to move from the departmental systems of the present to the computer-based medical record system of the future.

Observations on the effect of chimeric anti-CD4 monoclonal antibody in patients with mycosis fungoides

Chimeric (murine/human) anti-CD4 monoclonal antibody was infused into seven patients with mycosis fungoides. Successive patients received doses of 10, 20, 40, and 80 mg of antibody twice a week for 3 consecutive weeks. All patients had some clinical improvement, but responses were of relatively short duration. Serum levels of chimeric antibody varied as a function of dose. At the 80-mg dose level, antibody was readily observed in biopsied skin lesions. Although there was coating by antibody of most CD4 positive cells in the blood, there was no significant depletion of CD4 positive cells. Low-level antibody responses against the mouse Ig variable region and human Ig allotypic constant region determinants were observed in several patients, but none were of clinical significance. All but two patients made primary antibody and T-cell proliferative responses to a simultaneously administered foreign protein test antigen. However, there was marked suppression of the mixed lymphocyte reaction. We conclude that at the dose levels studied, a chimeric anti-CD4 monoclonal antibody (1) had some clinical efficacy against mycosis fungoides; (2) was well tolerated; (3) had a low level of immunogenicity; (4) had immediate immunosuppressive effects; and (5) did not induce tolerance to a co-injected antigen.

The Physician's Workstation: an example of end user integration of information systems

Many hospitals today have implemented widely disparate information systems on mainframe and mini-computer hardware. The advent of network technology in hospitals has made it possible to access information in these systems. Unfortunately, the user interfaces to applications on these system are unique and difficult to learn, which makes them unsuitable for use by clinical services. In this paper we describe the development using rapid prototyping object-oriented programming tools of a Physician's Workstation which integrates information from five different applications running on three separate computer systems.

Catabolism of geraniol by cell suspension cultures of Citrus limon

The addition of geraniol to cell suspension cultures of Citrus limon resulted in the rapid formation of nerol, citronellol, geranic acid and citronellic acid. Concurrently, a transient accumulation of bound forms of branched chain fatty acids, and, with a few hours delay, of regular chain C2 to C12 fatty acids was elicited. A concerted action of combined alpha/beta-oxidation enzymes on the terpenic acids, followed by an enlarged acetyl CoA pool is suggested. Terpene catabolism in plants and in vitro plant cells is discussed.

Immediate "steroid flare" from intraarticular triamcinolone hexacetonide injection: case report and review of the literature

We describe a patient who had an immediate, intense, localized synovitis due to intraarticular triamcinolone hexacetonide injection. The reaction was secondary to rapid intracellular ingestion of the steroid microcrystals as demonstrated by compensated polarized microscopy. We report the unique nature of this patient's response, and we review previous literature regarding "steroid flare" after intraarticular injection.

Febrile presentation of calcium pyrophosphate dihydrate deposition disease

Three patients were found to have calcium pyrophosphate dihydrate deposition disease (CPPD) as the cause of prolonged fever and elevated sedimentation rate. All responded to treatment. CPPD should be considered in evaluating patients with fever and high sedimentation rate.