C3H mice were immunized with MH134 tumors modified with two different chemicals, DEPC and TNBS, and the tumor-neutralizing activities of the spleen cells were examined after separating the cells by a Nylon-wool column, plastic dish, or treatment with specific antibodies (anti-mouse IgG and anti-mouse θ sera). The effector cells induced in mice by immunization with TNBS-treated tumors were T cells. In contrast, in the case of tumors modified with DEPC, macrophages were the major effector cells. The effects of chemical modification on the solubilization of cell surface proteins was also examined. DEPC inhibited solubilization of specific proteins from tumor cell surfaces, while TNBS did not have such an effect on the solubilization of proteins. These results indicate that the antitumor response in mice primed with DEPC-modified tumor is different from the case of TNBS-modified tumors, and that the immunological significance of chemical modification with DEPC is supposedly due to the stabilization of antigenic proteins on the tumor cell surface.

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Sweet aspartyl di- and tripeptide esters were extended toward the N-terminus in relation to the structural features of sweet peptides. The sweet peptides were designed on the basis of the receptor site model. It was found that an extension of the sweet aspartyl dipeptide esters by adding a small D-amino acid residue mostly gave sweet compounds (e.g., D-Ala-L-Asp-D-Ala-OMe), although this significantly decreased their sweetness potencies. Further extension at the N-terminus of the extended sweet tripeptide esters to yield the tetrapeptide esters resulted in a loss of the sweet taste. The N-terminal extension of sweet aspartyl tripeptide esters resulted in faintly sweet or nonsweet tetrapeptide esters. Interestingly, an analogous extension at the N-terminus of the sweet aminomalonyl dipeptide esters gave bitter compoundse.g.., D-Ala-DL-Ama-L-Phe-OMe). These results indicate that the receptor has a small space that can accomodate an additional small D-amino acid residue at the site facing the N-terminus of sweet aspartyl dipeptide esters.

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Equimolecular amounts of L-cysteine and dihydroxyacetone were heated at 110°C for 3hr in different solvent systems such as deionized water, glycerine, or triglyceride. The resulting mixtures were vacuum steam-distilled and each distillate was extracted with ethyl ether. The volatiles in the ether extracts were analyzed by gas chromatography and gas chromatography-mass spectrometry. Differences in the quality and quantity of volatiles formed in the systems were observed. Pyrazines, thiazoles, thiophenes, and some other sulfur-containing compounds were identified in the volatiles. Dimethylpyrazines were formed as major volatiles in the glycerine and triglyceride systems but were minor in the water system. 2-Acetylthiazole in the triglyceride system and 2-acetylthiophene in the glycerine system were secondary abundant products. In the water system, l-mercapto-2-propanone was found as a major volatile compound, and thiophenes as the next dominants.

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Inhibitory effects of lactic acid bacteria for dairy use on the mutagenicities of some volatile nitrosamines were investigated in vitro using a Salmonella typhimurium TA 98 streptomycin-dependent strain (SD 510) as an indicator bacterium. Among 40 strains examined, Leuconostoc paramesenteroides R-62, R-8, Streptococcus lactis subsp. diacetylactis R-63, and St. cremoris R-48 strongly inhibited the mutagenicity of N-nitroso-diethylamine (NDEA) and moderately N-nitrosodimethylamine (NDMA), but not N-nitroso-piperidine (NPIP) or N-nitroso-pyrrolidine (NPYR). In addition, the filtrates obtained from cell suspensions of the lactic acid bacteria examined inhibited the mutagenicity of NDEA.

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The SN-07 chromophore is a unique anthracycline antibiotic which is a constituent of the new macromolecular antitumor antibiotic SN-07. SN-07 chromophore prevented growth of mouse lymphoid leukemia L1210 cells and Staphylococcus aureus 209P at concentrations of 0.016 and 100ng/ml, respectively. SN-07 chromophore inhibited DNA synthesis by 50% at 0.034 μg/ml and RNA synthesis at 0.0125 μg/ml in L1210 cells, and similarly at 0.075 and 0.130 μg/ml in S. aureus, but did not inhibit protein synthesis in either cell type. These inhibition patterns indicate that SN-07 chromophore is a class I anthracycline antibiotic.
We constructed two types of SN-07 chromophore-DNA complex, SN-07 chromophore-poly(dIdC)•poly(dI-dC) complex (intercalation type) and SN-07 chromophore-poIy(dG-dC)•poly(dG-dC) complex (covalent binding type), as models of the macromolecular antibiotic SN-07. The activities were different from those of free SN-07 chromophore in vitro and in vivo. Such a modification would represent a new drug delivery system for SN-07 chromophore.

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Positive fast atom bombardment tandem mass spectrometry (FAB-MS/MS) was applied for peptide sequencing, particularly for determining the gamma glutamyl linkage involved in metal-binding peptides such as Cadystin (γEC)₃G = Cadystin A and Cadystin (γEC)₂G = Cadystin B (MW 771 and 539, respectively). The fragmentation patterns between the natural gamma glutamyl peptide and the synthetic alpha glutamyl one were clearly distinguishable. FAB-MS/MS was proved to be a good method for determining these peptides, since it needed no chemical degradation and only a small amount of the peptide was needed for determination.

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The translational elongation activity in hepatic protein synthesis was compared analytically between starved and refed young rats using an efficient liver slice system. The average ribosome transit time and chain completion time as an estimate of the elongation activity of peptide synthesis were measured. The results were as follows:
1) the average ribosome transit time of liver slices from refed rats was 2.8 min and that from starved rats was 3.6 min; and
2) the average chain completion time of starved rats was estimated at 3.4 min and that of refed rats at 2.7 min.
These results indicate-that refceding a complete diet to a starved rat significantly shortens the ribosome transit time or peptide chain completion time by about 0.7 to 0.8 min. This stimulation of elongation activity contributes in part to the rapid enhancement of liver protein synthesis induced by refeeding in starved rats. The possible mechanism for this induction should be proposed as posttranscriptional control since the amount and size distribution of hepatic polyA(+)mRNA was conserved after refeeding to the starved rats.

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Interspecific protoplast fusion between Aspergillus oryzae and Aspergillus sojae and subsequent haploidization of the fusants were done to search for a further possibility in breeding of new koji-molds for soy sauce fermentation. Fusion between the yellow-spored, met^- mutant of A. oryzae and the white-spored, bio^- mutant of A. sojae produced green-spored-fusants on the minimal medium with a frequency of 5 × 10^-5 per protoplast pairs. The fusants, which were thought to be heterokaryons for their frequent segregation of the parental marker strains, could be stabilized through repeated subcultures. The resulted green-spored-diploids were haploidized with benomyl, and a variety of phenotypes including recombinants were obtained. The haploidized recombinants were obtained with a frequency of 0.97-1.25 × 10^-1. Behaviors of some phenotypic properties in the fusants and the haploidized segregants were investigated. Although markers of conidial color and auxotrophies were complemented in the fused diploids, the morphology of conidial walls of only A. oryzae-type (rough) or A. sojae-type (echinulate) was observed in the diploids and no intermediate type appeared. Gel electrophoresis of the extracellular alkaline proteinases from the diploids and the haploidized recombinants showed that they produced one of the A. oryzae type or A. sojae type but not both.

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In the yeast Saccharomyces cerevisiae, the gene FL01 and the gene FL05 are dominant flocculation genes. In diploid cells heterozygous for MAT, however, expression of the FL01 gene was greatly diminished as far as we examined, as seen in the FL08 gene. On the other hand, expression of the FL05 gene was not affected by the mating-type locus. Several brewer's and wine flocculent yeast cells showed the flocculence phenotype defined as the FL05 type. These results suggested the usefulness of the FL05 gene in improvement of the flocculation properties of industrial strains.

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The effect of a dietary supplementation of corn hemicellulose (10g/day for 10 days) extracted from corn hull on fecal weight, moisture, pH, microflora, ammonia content, and on the activities of β-glucuronidase, β-glucosidase and nitroreductase were studied in nine healthy volunteers. Corn hemicellulose increased the fecal weight, lowered the fecal pH, decreased the fecal ammonia content, and decreased the β-glucuronidase and nitroreductase activities (per gram of wet feces and daily output) significantly (p<0.05). β-Glucosidase activity per gram of wet feces was decreased, but its daily output did not change. No remarkable changes in the fecal flora were observed at the bacterial group level. The results demonstrate that corn hemicellulose significantly influenced the fecal bulk and harmful bacterial products.

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When taro tubers (Colocasia antiquorum Schott) were inoculated by a taro strain (compatible or pathogenic) or a sweet potato strain (incompatible or non-pathogenic) of Ceratocystis fimbriata, lipid peroxidation, which was measured by the thiobarubituric acid reaction, took place to a similar magnitude and with a similar course in both kinds of tubers. Throughout the incubation period, no generation of superoxide anions (O₂^-) due to inoculation by either strain was detected in the tubers. The activities of phospholipase A₂ and lipoxygenase changed in a manner accounting for the production of lipid peroxides observed in taro tubers inoculated by both strains. The sweet potato and taro strains had similar sensitivity to the toxicity of peroxides of linolenic acid and lipid peroxides from inoculated taro tubers. These results suggested that lipid peroxide produced by the host plant was involved in the early host-parasite interaction in this system.

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The enzymatic transglucosylation to synthesize a chemically stable form of I -ascorbic acid (AA) was further investigated by using commercially available enzymes. Among various glycosidases examined, only rice seed α-glucosidase could produce a nonreducing and stable glucoside of AA, which was identified as 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G). The enzyme showed the same regioselective transglucosylase activity as rat intestinal α-glucosidase that had been demonstrated by us to be effective in this reaction, although these two enzymes had different pH optima for maltose hydrolysis. The substrate specificity of rice α-glucosidase for AA-2G formation was considerably different from that of rat α-glucosidase. However, both α-glucosidases had high specificity for the α-1, 4-glucosidic linkage but not α-1, 6, suggesting that they can catalyze a preferential transglucosylation to the 2-position but not to the 6-position of AA. Thus, these results allows us to produce a sufficient amount of AA-2G with rice seed α-glucosidase for its application to medicinal and other uses.

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Dialdehyde derivatives of cellulose (GE) and α-cyclodextrin (α-CD) were prepared by the periodate oxidation method. Linkage formation between cellulose dialdehyde (dial-CE) and bovine serum albumin (BSA) proceeded rapidly at pH 9.0 and gave a maximum yield at about 30 hr. Among the various amino compounds tested, ethylenediamine, hexylamine, hexamethylenediamine and BSA were bound effectively to the dial-CE in this order. As compared with the case of dial-CE, reactions between α-CD dialdehyde (dial-CD) and amino compounds proceeded rather slowly. Separation of dial-CD isomers linked with glycine by a DEAE-Sephacel column resulted in several peaks. However, the components of each fraction were not homogeneous. Reactions of dialdehyde derivatives with amino compounds were thought to produce a 4-oxa-azepine-type of complex.

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A simple and sensitive assay method for glucanase activity was established using fluorescent polysaccharide substrates. Periodate oxidized α-glucans having dialdehyde were covalently attached to the fluorescent reagent via Schiff base formation followed by NaBH₄ reduction. Ethylenediaminonaphthalene (EDAN) was effective to produce a stable and highly fluorescent polysaccharide. ED AN derivatives of glycogen and dextran dialdehyde were useful substrates for Taka-amylase A and endodextranase, respectively. Two cellulases were shown to release water-soluble fluorescent products from the EDAN derivative of cellulose powder. Moreover, the action of the exo type of enzyme such as glucoamylase was readily distinguished from that of the endo type of enzyme because the attached EDAN prevented the attack of exo-enzyme.

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A series of 4-alkylthio-1, 2-dithiolanes were synthesized from S, S'-(2-alkylthiotrimethylene) di(benzenethiosulfonates), and their biological activities were tested on Culex pipience molestus, Laodelphax striatellm and Tetranychm urticae. These compounds showed potent activity against both insect species, the strongest being displayed by 4-ethylthio-1, 2-dithiolane and 4-isopropylthio-1, 2-dithiolane.

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A series of 5-alkylthio-1, 3-dithianes were synthesized from S, S'-(2-alkylthiotrimethylene) di(benzenethiosulfonates). These compounds showed biological activity against Culex pipience molestus, Laodelphax striatellus and Tetranychus urticae. Potent activity was displayed by 2-cyano-2-(lpyrrolidino)carbonyl-5-isopropylthio-1, 3-dithiane.

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The occurrence of free O-phosphoserine and O-phosphothreonine in porcine liver is demonstrated. These amino acids were separated from the tissue extracts by anion- and cation-exchange chromatography and thin-layer chromatography, and were identified by gas chromatography with flame photometric detection and gas chromatography-mass spectrometry. The contents of O-phosphoserine and O-phosphothreonine in the liver were estimated to be 377±13ng/g and 115±2ng/g, respectively.

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Dry seeds of soybean [Glycine max (L.) Merr. cv. Bay] were irradiated with X-rays (21.4kR) and the M₂ progeny was evaluated for linolenic acid (18:3) content in the oil. A significant amount of genetic variability was observed for linolenic acid content in the oil of Bay cultivar after X-ray irradiation compared with the control. Out of 3, 000 M₂ plants, a mutant was identified, M923, in which the linolenic acid content accounted for 4.4 percent, about half the amount of the original variety. An inverse relationship between linoleic acid and linolenic acid contents was observed. The mutant M923 always had lower linolenic acid content in different environmental conditions in the M₃ generation.

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This experiment was performed to investigate the possibility that N'-methylnicotinamide (N'-methyl-3-pyridinecarboxamide) and nicotinamide N-oxide have niacin activity or not in animals. When 20 mg N'-methylnicotinamide per mouse was administered, urinary excretion of nicotinamide, N¹-methylnicotinamide (MNA), N¹-methyl-2-pyridone-5-carboxamide (2-Py), and N¹-methyMpyridone-3-carboxamide (4-Py) increased 24-, 3-, 3-, and 3-fold, respectively, compared with the control values. The increased ratios of MNA, 2-Py, and 4-Py were almost the same as those when 20 mg nicotinamide was administered. Therefore, the relative activity of N'-methylnicotinamide to nicotinamide as niacin was considered to be about 1. When 20 mg nicotinamide N-oxide per mouse was administered, urinary excretion of nicotinamide, MNA, 2-Py, and 4-Py increased 6.4-, 1.8-, 1.6-, and 1.7-fold, respectively, compared with the control values. The increased ratios of MNA, 2-Py, and 4-Py were about 1/2 of those when 20 mg nicotinamide was administered, so the relative activity of nicotinamide N-oxide to nicotinamide as niacin is considered to be about 1/2. In conclusion, it was found the possibility that the reactions N'-methylnicotinamide→nicotinamide and nicotinamide N-oxide→nicotinamide occur, at least in mice, and that therefore N'-methylnicotinamide and nicotinamide N-oxide have niacin activity.

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Seven pigments including four new anthocyanins, caffeylmalonylcyanin, malonyl-cis-shisonin, caffeylcyanin and cis-shisonin, were isolated from Perilla leaves. The complete structures of these new anthocyanins were elucidated to be cyanidin 3-(6-O-trans-caffeylglucoside)-5-(6-O-malonylglucoside), 3-(6-O-cis-p-coumarylglucoside)-5-(6-O-malonylglucoside), 3-(6-O-trans-caffeylglucoside)-5-glucoside and 3-(6-O-cis-p-coumarylgIucoside)-5-glucoside, respectively. The cis-trans isomerization and stability of these pigments are also described.

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Stereochemically pure pheromone components of the pine sawfly, acetates of (2S, 3S, 7S)- and (2S, 3R, 7R)-3, 7-dimethylpentadecan-2-ol, were prepared by an improved synthetic procedure. Mixtures of the newly prepared compounds were tested in the field (red pine forests in Hyogo and Nagano, Japan) for their attraction of Neodiprion sertifer. The maximum response was observed in mixtures of the ratio (2S, 3R, 7R)/(2S, 3S, 7R)-10^-3:1 to 10^-4:1. When the results are compared with those in Michigan, U.S.A., N. sertifer in Japan responded less specifically to certain blending ratios of diastereomers than in America.

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Two alkyl glycosides cetyl-β-glucoside (C₁₆-Glu) and cetyl-β-galactoside (C₁₆-Gal), were synthesized and the thermal properties of their water systems were examined using differential scanning calorimetry (DSC). These compounds form bilayer structures. The C₁₆-Glu-H₂O system shows five endothermic peaks due to the phase transition from gel to a liquid crystalline state at 86, 73, 68, 57, and 47°C, depending on the amount of added water, i.e., the degree of hydration. In the samples containing enough water, which means that free water coexists with hydrated water, the lowest two peaks at 47 and 57°C were observed and their intensity ratio changed in each run depending on the thermal history of the sample. It was explained by the presence of two kinds of hydrated states. An ESR study of the TEMPO parameter showed that these transitions come partly or wholly from the melting of the alkyl chains. The C₁₆-Gal-H₂O system showed three peaks, but did not show any hysteresis. The difference between C₁₆-Glu and C₁₆-Gal systems was discussed from the viewpoint of intermolecular force between headgroups.

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The gene encoding an extracellular Rhizopus niveus aspartic proteinase I (RNAP-I) was introduced into Saccharomyces cerevisiae. The yeast Cell carrying a plasmid containing the intact RNAP-I gene under the control of the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene promoter of S. cerevisiae did not synthesize RNAP-I at all. On the other hand, when the intron of the RNAP-I gene had been removed from the gene in the plasmid, the cell secreted RNAP-I with high efficiency. Processing of the pro-sequence occurred at the same region of the pro-enzyme during cultivation as observed in the culture of R. niveus. Moreover, the promoter and the terminator of the original RNAP-I gene were found to be weakly functional in the yeast cell with respect to expression of the intronless RNAP-I gene, although the initiation and termination sites were heterogeneous. The effects of vector-types on the extracellular production of RNAP-I were also investigated.

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(±)-Tricarbonyl(η⁵-1-formyl-2-methylcyclopentadienyl)manganese (1) was optically resolved with horse liver alcohol dehydrogenase (HLADH) and two species of yeasts, Saccharomyces sp. H-1 and Rhodotomla rubra IFO 889. Usually, (1R)-1 was preferentially reduced to give (-)-alcohol 2 of ≤ 97% e.e. -84% e.e. Ketone analogue (±)-tricarbonyl(η⁵-1-acetyl-2-methylcyclopentadienyl)manganese (4) was reduced by the yeasts. The major product by S. sp. H-1 was the (1S, 2R, 1'S-(+)-alcohol (5) (≥98% e.e.) and the minor product, the (1R, 2S, 1'S)-(-)-alcohol (6) (86% e.e.). R. rubra gave only the latter alcohol (≥ 99 % e.e.). The stereodifferentiation mechanism for these bioreductions is discussed in terms of the Prelog rule. The mechanism for HLADH reduction was examined with computer graphics.

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A new restriction endonuclease, designated as ApaLI, was purified from cell-free extracts of Acetobacter pasteunanus IFO 13753 by streptomycin treatment, ammonium sulfate fractionation, combined column chromatographies on heparin-Sepharose CL-6B and DEAE-Sepharose CL-6B and Fast Protein Liquid Chromatography on Mono Q HR 5/5. The purified enzyme was homogeneous on polyacrv lamide gel disc electrophoresis. The molecular weight of the purified enzyme was calculated as 26, 000 daltons by gel filtration using Sephadex G-200, and the isoelectric point of the purified enzyme was 4.8 by ampholine sucrose-density gradient isoelectric focusing. The purified enzyme cleaved λ, Ad2, SV40, M13mp18 RF I, φX174 RF I and pBR322 DNAs at 4, 7, 0, 0, 1 and 3 sites, respectively. The purified enzyme worked best at 37°C and pH 8.0 in a reaction mixture (50 μl) containing 1.0 μg λDNA, 10mM Tris-HC1, 7 mM 2-mercaptoethanol, 7mM MgCl₂ and 25 mM NaCl. However, the purified enzyme did not require NaCl necessarily for the enzyme reaction. The purified enzyme recognized the palindromic hexanucleotide DNA sequence, 5'-GTGCAC-3' and cut between G and T, producing a 5'-cohesive tetranucleotide extension.

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A new restriction endonuclease, designated as AgeI, was purified from cell-free extracts of a marine bacterium, "Agrobacterium gelatinovorum" IAM 12617 by streptomycin treatment, ammonium sulfate fractionation, combined column chromatographies on heparin-Sepharose CL-6B and DEAE-Sepharose CL-6B and FPLC on Mono Q (HR 5/5) and Superose 12 (HR 10/30). The purified enzyme was homogeneous on SDS-polyacrylamide gel disc electrophoresis and free from other phosphatase and exonuclease activities on ligation-recutting test. The relative molecular mass of the enzyme was 24, 000 daltons by SDS-polyacrylamide gel disc electrophoresis. The gel filtration using Superose 12 (HR 10/30) gave the same calculation (23, 000 daltons). These data indicated that the enzyme is a monomer. The isoelectric point of the enzyme was 6.5. The purified enzyme cleaved λ and Ad2 DNAs at 10 or more and 5 sites, respectively. However, the purified enzyme did not cleave SV40, φX174 RF I, M13mp18 RF I or pBR322 DNAs. pBR328 DNA was cleaved at 1 site by the purified enzyme. The purified enzyme worked best at 37°C and pH 7.5 in a reaction mixture (50 μl) containing 1.0μg λDNA, 10mM Tris-HC1, 7mM 2-mercaptoethanol, 7mM MgCl₂ and 50mM NaCl. The purified enzyme did not require monovalent cations necessarily for the enzyme reaction. The enzyme recognized the palindromic hexanucleotide DNA sequence 5'-ACCGGT-3' and cut between A and C, producing a 5A-cohesive tetranucleotide extension.

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Peptides with affinity for opioid receptors were found in an artificially methyl-esterified peptic digest of human lactoferrin. Three active peptides were purified by two steps of reverse-phase high-performance liquid chromatography. Their structures were Tyr-Leu-GIy-Ser-Gly-Tyr-OCH₃, Arg-Tyr-Tyr-Gly-Tyr-OCH₂, and Lys-Tyr-Leu-Gly-Pro-Gln-Tyr-OCH₃, which respectively correspond to the methyl esters of residues 318-323, 536-540, and 673-679 of human lactoferrin.
The IC₅₀ values of these peptides were 15, 10 and 23 μM, respectively, in a radioreceptor assay in the presence of 1 nM [³H]naloxone. In the myenteric plexus preparation of the longitudinal muscle of guinea pig ileum, the individual peptides had no opioid agonist activities, but they antagonized [Met⁵]enkephalin and morphiceptin when they were at a concentration of 10^-610^-5 M, suggesting that these were the opioid antagonist peptides. These three opioid antagonist peptides were named lactoferroxin A, B and C, after casoxin, the opioid antagonist peptide derived from bovine k-casein.
Concerning the antagonist activities of lactoferroxins for opioid receptor sub-types, lactoferroxin A showed preference for μ-receptors, while lactoferroxin B and C had somewhat higher degrees of preference for k-receptors than for μ-receptors.
A study of the structure-activity relationship of the three lactoferroxins and their synthetic analogues showed that these opioid antagonist peptides derived from food protein could be expressed by the general formula X_A-Tyr-X_B-Tyr-OCH₃. An amino acid in position X_A may affect the specificity of the antagonist peptide for opioid receptor sub-types.

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δ-Acetyl-L-ornithyl-β-alanine methyl ester is an un-sweet peptide as a salt-free compound with AH and X units among the sweetness-causing trifunctional units, AH, B, and X. However, it had sweetness when an acid component (i.e. HC1) as a B unit was added. We called peptide sweeteners, of which trifunctional units were located on more than one molecule, "Intermolecule type sweetener." In this investigation, we found that we could design sweeteners more easily by using the idea of intermolecule type sweetener system.

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A novel method for producing optically active 1, 2-diols by microbial Stereoinversion was developed. It was found that some microorganisms could convert only (R)-1, 2-pentanediol in the racemate to the (S)-enantiomer. Candida parapsilosis produced 27.9 g/l of (S)-1, 2-pentanediol from 30g/l of the racemate in 24 hr of reaction (molar yield 93%, enantiomeric excess 100%). This Stereoinversion proceeded via oxidation of (R)-1, 2-pentanediol to 1-hydroxy-2-pentanone by an NAD⁺-linked (R)-specific alcohol dehydrogenase and reduction of 1-hydroxy-2-pentanone to (S)1, 2-pentanediol by an NADPH-linked (S)-specific 2-keto-1-alcohol reductase. This microbial stereoinversion was applicable to ten 1, 2-diols. Optically active 1, 2-diols prepared by the reaction had the same configuration at the chiral center.

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Two cell-associated yeast enzyme systems have been shown to be influenced by the addition of biochemically inert colloidal particles to the growth medium. Titers of the alcohol oxidase enzyme system of Pichia pastoris and the β-glucosidase system of Candida wickerhamn were amplified up to 3-fold through the addition of small (5-10 g/1) amounts of commercial aluminum oxide particles. This discovery is of importance from an applied perspective as a means of increasing biocatalytic efficiency. As well, it provides a means of studying the physiological changes associated with cell sorption, independent of confounding influences such as diffusional limitations that are normally associated with film growth.

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