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The cellulose-binding ability of Geotrichum sp. M111 cells was investigated by the micro-tube method which gives an indication of the binding ability of M111 cells. The optimum pH value and temperature were 3-7 and below 50 degrees C, respectively, from measurement of the aggregation height for a mixture of cellulose powder and M111 cells. The binding constant of 0.3% for M111 cells to cellulose powder was obtained in a 20 mm citrate buffer of pH 5.0 at 30 degrees C. Aggregation was inhibited by such surfactants as sodium dodecylsulfate. The binding ability of M111 cells to cellulose fiber disappeared after a treatment with Driselase or Pronase E. This suggests that the binding ability might be related to the cell surface proteins. The dehydration rate of the distilled waste of sweet potato shouchu was accelerated by the addition of M111 cells. The analysis of dehydration by a linear viscoelastic model suggests that the acceleration effect might have been due to the space increase between cellulose fibers with the cell addition.

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The taste and flavor of spray-dried powdered products are the most important quality factors. In the present study, molecular encapsulation in cyclodextrin was applied to prevent the loss of a hydrophobic flavor compound (l-menthol) during the drying of a droplet. beta-Cyclodextrin appeared to be a better encapsulant for menthol than alpha- and gamma-cyclodextrin. The retention of menthol increased with increasing concentration of both cyclodextrin and maltodextrin. A simple mathematical model is proposed for estimating the flavor retention. The theoretical results by this model estimated well the final retention of menthol encapsulated in a blend of beta-cyclodextrin and maltodextrin.

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Anhydrous sugars such as maltose and trehalose are useful for making dry powder of foods and liquids. The crystal-transformation rate of maltose and trehalose were investigated under humid conditions and by kneading. The enthalpy for solubilization was 7.0 kJ/mol for the anhydrous maltose. The crystal-transformation rate of anhydrous alpha-maltose to hydrous beta-maltose depended on the temperature at 75% humidity. However, that of anhydrous trehalose did not depend on the temperature, and transformation was very rapid. An anomeric change to maltose and no such change to trehalose might have caused this. The activation energy of crystal transformation was 79 kJ/mol for maltose and zero for trehalose. The rate of crystal transformation of anhydrous maltose while kneading depended on the purity of the anhydrous alpha-maltose and the amount of water present. This crystal transformation rate fitted the Avrami equation.

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Refolding of reduced and denatured protein in vitro has been an important issue for both basic research and applied biotechnology. Refolding at low protein concentration requires large volumes of refolding buffer. Among various refolding methods, diafiltration is very useful to control the denaturant and red/ox reagents in a refolding solution. We constructed a refolding procedure of high lysozyme concentration (0.5-10 mg/ml) based on the linear reduction of the urea concentration during diafiltration under oxygen pressure. When the urea concentration in the refolding vessel was decreased from 4 M with a rate of 0.167 M/h, the refolding yields were 85% and 63% at protein concentrations, 5 mg/ml and 10 mg/ml, respectively, after 11 h. This method gave a high productivity of 40.1,microM/h of the refolding lysozyme. The change in refolding yields during the diafiltration could be simulated using the model of Hevehan and Clark.

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The on-line control of enzyme-production processes is difficult, owing to the uncertainties typical of biological systems and to the lack of suitable on-line sensors for key process variables. For example, intelligent methods to predict the end point of fermentation could be of great economic value. Computer-assisted control based on artificial-neural-network models offers a novel solution in such situations. Well-trained feedforward-backpropagation neural networks can be used as software sensors in enzyme-process control; their performance can be affected by a number of factors.

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The autoxidation of such n-3 polyunsaturated fatty acid (PUFA) ethyl esters as ethyl eicosapentaenoate and ethyl docosahexaenoate was investigated at various temperatures. Extensive studies of the oxidative reaction for ethyl eicosapentaenoate were carried out at different oxygen levels. At the same oxygen level and temperature, the autocatalytic reaction rate, by which oxidation progressed in the first half period, was about 1.5-2.5 times larger than the first-order reaction rate which governed the oxidation in the second half period. The reaction rate constants for ethyl eicosapentaenoate at different oxygen levels correlated well with the Langmuir-type equation of the oxygen concentration, in which the Langmuir parameter was independent of temperature.

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On the basis of an autocatalytic and a first order reaction kinetics, a nonisothermal oxidation reaction model was developed for n-3 polyunsaturated fatty acid (PUFA) under temperature-programmed linear heating conditions. With this model, the activation energy of oxidative reaction can easily be obtained with at least three linear heating conditions. The temperature-programmed oxidation experiments of ethyl eicosapentaenoate and ethyl docosahexaenoate were done under linear heating conditions of 4 to 12 K/h. The activation energies and the frequency factors obtained were in good agreement with those by the isothermal oxidation experiments reported previously.

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The interest in the applications of biocatalysis in organic syntheses has rapidly increased. In this context, lipases have recently become one of the most studied groups of enzymes. We have demonstrated that lipases can be used as biocatalyst in the production of useful biodegradable compounds. A number of examples are given. 1-Butyl oleate was produced by direct esterification of butanol and oleic acid to decrease the viscosity of biodiesel in winter use. Enzymic alcoholysis of vegetable oils without additional organic solvent has been little investigated. We have shown that a mixture of 2-ethyl-1-hexyl esters can be obtained in a good yield by enzymic transesterification from rapeseed oil fatty acids for use as a solvent. Trimethylolpropane esters were also similarly synthesized as lubricants. Finally, the discovery that lipases can also catalyze ester syntheses and transesterification reactions in organic solvent systems has opened up the possibility of enzyme catalyzed production of biodegradable polyesters. In direct polyesterification of 1,4-butanediol and sebacic acid, polyesters with a mass average molar mass of the order of 56,000 g mol-1 or higher, and a maximum molar mass of about 130,000 g mol-1 were also obtained by using lipase as biocatalyst. Finally, we have demonstrated that also aromatic polyesters can be synthesized by lipase biocatalysis, a higher than 50,000 g mol-1 mass average molar mass of poly(1,6-hexanediyl isophthalate) as an example.

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The interfacial activation of Rhizomucor miehei lipase (RmL) involves the motion of an alpha-helical region (residues 82-96) which acts as a "lid" over the active site of the enzyme, undergoing a displacement from a "closed" to an "open" conformation upon binding of substrate. Normal mode analyses performed in both low and high dielectric media reveal that low-frequency vibrational modes contribute significantly to the conformational transition between the closed and open conformations. In these modes, the lid displacement is coupled to local motions of active site loops as well as global breathing motions. Atomic fluctuations of the first hinge of the lid (residues 83-84) are substantially larger in the low dielectric medium than in the high dielectric medium. Our results also suggest that electrostatic interactions of Arg86 play an important role in terms of both the intrinsic stability of the lid and its displacement, through enhancement of hinge mobility in a high dielectric medium. Additional calculations demonstrate that the observed patterns of atomic fluctuations are an intrinsic feature of the protein structure and not dependent on the nature of specific energy minima.

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Industrial applications of enzyme technology are rapidly increasing. On-line control of enzyme production processes, however, is difficult owing to the uncertainties typical of biological systems and to the lack of suitable on-line sensors for key process variables and quality attributes. We demonstrate that well-trained feedforward backpropagation neural networks with one hidden layer can be employed to overcome such problems with no need for a priori knowledge of the relationships of the process variables involved. Neural network programs were written in Microsoft Visual C++ for Windows and implemented in a personal computer. The goodness of fit of the trained neural network to the reference data was determined by the coefficient of determination, R2. Case studies of beta-galactosidase, glucoamylase, lipase, and xylanase production processes will be used as examples.

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The molecular inclusion powder of d-limonene in ß-cyclodextrin was prepared by using a twin-screw kneader at a low water content. The influence of water and alcohol content on the formation of the inclusion complex was studied in comparison with the inclusion complex obtained by the micro-aqueous method. The inclusion fraction of d-limonene in the complex powder in ß-cyclodextrin was much higher than that made by the micro-aqueous method. The marked differences in the inclusion fraction were observed particularly at the molar water ratio to ß-cyclodextrin of less than 10. The inclusion fraction increased sharply with the increase in the kneading torque. This means that the energy of kneading increased the inclusion of d-limonene. A mathematical model for estimating the inclusion fraction was derived by combining the effects of water and the kneading energy on the formation of the inclusion complex.

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Complex formation of poorly water soluble organic compounds with cyclodextrin (CD) is quite difficult in an aqueous cyclodextrin system. Formation of the inclusion complex of d-limonene, phenyl ethanol, acetophenone, or menthol was investigated in a slurry form of α-, ß-, or γ-CD in organic solvents or alcohol under anhydrous conditions. Ethanol and methanol were found to be good solvents for this method. The use of ethanol as the solvent was investigated in greater detail. There existed an optimal amount of ethanol for the maximum inclusion of d-limonene as the guest compound. However, an excess of ethanol inhibited the inclusion. An adsorption model of alcohol on CD, analogous to the substrate inhibition model of enzyme kinetics, could correlate the inclusion ratio with the amount of alcohol added to CD.

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OBJECTIVES: The aim of this study was to find out the amount, type, and localisation of acute orienteering injuries in the 1995 Finnish Jukola (men's) and Venla (women's) relay competitions with 9724 participants. METHODS: Patient data were collected on a preplanned form at the first aid station. RESULTS: There were 244 acute competition injuries. The overall injury incidence was 2.5% (95% confidence interval (CI) 2.2 to 2.8), 2.3% in the men's relay and 3.2% in the women's relay, and the difference between incidences among men and women was statistically significant (odds ratio (OR) 1.4; 95% CI 1.1 to 1.9). The injury rates were also calculated per 1000 competition hours and per 1000 km and were 15.4 and 2.6 respectively. Most of the injuries could be treated at the first aid station. Female orienteers had more blisters (OR 4.4; 95% CI 2.5 to 7.9) and fewer wounds (OR 0.5; 95% CI 0.2 to 1.0) than male orienteers. Injuries occurred mostly in the lower extremities (70%), and ankle sprains accounted for 25% of all injuries. Injuries were more common during the first leg of both relays. CONCLUSIONS: This study shows the heavy workload in a first aid station of a big orienteering relay competition. It indicates a difference in injuries between the sexes and in the different stages of the relay, which should be further investigated in order to prevent orienteering competition injuries.

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Human P450 2C19 is selective for 4'-hydroxylation of S-mephenytoin and 5-hydroxylation of omeprazole, while the structurally homologous P450 2C9 has low activity toward these substrates. To identify the critical amino acids that determine the specificity of human amino acids that determine the specificity of human P450 2C19, we constructed chimeras of p450 2C9 replacing various proposed substrate binding sites (SRS) with those of P450 2C19 and then replaced individual residues of P450 2C19 and then replaced individual residues of P450 2C9 by site-directed mutagenesis. The 339 NH2-terminal amino acid residues (SRS-1-SRS-4) and amino acids 160-383 (SRS-2-SRS-5) of P450 2C19 conferred omeprazole 5-hydroxylase activity to P450 2C9. In contract, the COOH terminus of P450 2C19 (residues 340-490 including SRS-5 and SRS-6), residues 228-339 (SRS-3 and SRS-4) and residues 292-383 (part of SRS-4 and SRS-5) conferred only modest increases in activity. A single mutation Ile99 --> His increased omeprazole 5-hydroxylase to approximately 51% of that of P450 2C19. A chimera spanning residues 160-227 of P450 2C19 also exhibited omeprazole 5-hydroxylase activity which was dramatically enhanced by the mutation Ile99 --> His. A combination of two mutations, Ile99 --> His and Ser200 --> Pro, converted P450 2C9 to an enzyme with a turnover number of omeprazole 5-hyrdroxylation, which resembled that of P450 /c19. Mutation of Pro221 --> Thr enhanced this activity. Residue 99 is within SRS-1, but amino acids 220 and 221 are in the F-G loop and outside any known SRS. Mutation of these three amino acids did not confer significant S-mephenytoin 4'-hydroxylase activity to P450 2C9, although chimeras containing SRS-1-SRS-4 and SRS-2-SRS-5 of P450 2C19 exhibited activity toward this substrate. Our results thus indicate that amino acids 99, 220, and 221 are key residues that determine the specificity of P450 2C19 for omeprazole.

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A real-time fuzzy-knowledge-based system for fault diagnosis and control of bioprocesses was constructed using the object-oriented programming environment Small-talk/V Mac. The basic system was implemented in a Macintosh Quadra 900 computer and built to function connected on line to the process computer. Fuzzy logic was employed in handling uncertainties both in the knowledge and in measurements. The fuzzy sets defined for the process variables could be changed on-line according to process dynamics. Process knowledge was implemented in a graphical two-level hierachical knowledge base. In on-line process control the system first recognizes the current process phase on the basis of top-level rules in the knowledge-base. Then, according to the results of process diagnosis based on measurement data, the appropriate control strategy is subsequently inferred making use of the lower level rules describing the process during the phase in question. (c) 1995 John Wiley & Sons, Inc.

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Immunoblot analysis of human livers using a monospecific antibody to rat CYP1A2 section demonstrated that the expression of CYP1A2 protein is highly variable in human liver. Quantitative PCR analysis was then employed to examine the interindividual variability of both CYP1A1 and CYP1A2 mRNAs in human liver. Hepatic content of CYP1A2 mRNA correlated significantly with levels of CYP1A2 protein as analysed by immunoblot analysis (r = 0.58; p < 0.01). CYP1A2 mRNA content varied > 40-fold among individuals while CYP1A1 content varied > 20-fold. CYP1A2 mRNA was higher than CYP1A1 mRNA (approximately two to 30-fold) in livers of different individuals. The individual with the highest CYP1A1 and CYP1A2 mRNA amounts was a current smoker, but mRNA expression in two other smokers was within the range observed among nonsmokers. The expression of the two CYP1A mRNAs correlated highly (r = 0.72; p < 0.0005) when smokers were included, but the correlation was less significant (r = 0.62; p < 0.05) in nonsmokers. We amplified a full-length CYP1A2 cDNA clone by PCR from a liver which expressed extremely low amounts of CYP1A2 protein. Sequence analysis indicated that exon 4 was missing in this clone, but no other sequence changes were found. PCR analysis demonstrated that both the normally spliced mRNA and abnormally spliced mRNA could be detected in all human livers examined, but the normally spliced mRNA was more abundant than the splice variant. Therefore, sequence changes in the coding region of CYP1A2 did not account for the poor expression of CYP1A2 in this individual.

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An object-oriented fuzzy expert system to support on-line control of an automated fermentation plant is described. The major elements of the system consist of a fuzzy inference engine, a database, a knowledge base, and an expression evaluater. The expression evaluater calculates specific rates for growth, and substrate and product formation at different physiological states during the cultivation from the measured data. The specific rates are then compared with the standard target rates stored in the database. If differences outside the set tolerances were observed, the inference engine analyses the reasons for the faults on the basis of the knowledge represented in the form of a knowledge network and fuzzy membership functions of the process variables. The fuzzy expert system was developed on the basis of a shell constructed by using the object oriented Smalltalk/V Mac programming environment, with Lac-tobacillus casei lactic acid fermentation as the example of process application.

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