The His-Asp phosphorelay signal transduction system has been identified in most organisms, including bacteria, yeasts, fungi, and plants, except for animals. This system is important in adaptation to stress, control of cell growth, and induction of development in response to environmental changes. On the basis of genomic information, it has been found that Aspergillus nidulans, a model species of fungi, includes 15 histidine kinases (HKs), one histidine-containing phosphotransmitter protein (HPt), and four reponse regulators (RRs) as factors related to the signal transduction system. In this review, it is explain that the His-Asp phosphorelay system is important in controling cell growth (responses to fungicides, the induction of asexual and sexual development, and so on) under different growth conditions with reference to A. nidulans.

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2-Oxoadipic acid, a key metabolite of tryptophan and lysine, reacted with 1,2-diamino-4,5-methylenebenzene in an acidic solution to produce a fluorescent derivative. The reaction product was separated using a Tosoh ODS-80Ts column with 20 mmol/L of KH₂PO₄–K₂HPO₄ buffer (pH 7.0) containing 26% methanol at a flow rate 0.8 mL/min. The excitation wavelength of detection was 367 nm, and the emission wavelength was 446 nm. The limit of quantification was 1 pmol per injection, sufficiently sensitive for the determination of 2-oxoadipic acid in human and experimental animal urine.

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The Rv3377c and Rv3378c genes from Mycobacterium tuberculosis are specifically found in the virulent Mycobacterium species, but not in the avirulent species. The Rv3378c-encoded enzyme produced tuberculosinol 2 (5(6), 13(14)-halimadiene-15-ol), 13R-5a and 13S-isotuberculosinol 5b (5(6), 14(15)-halimadiene-13-ol) as its enzymatic products from tuberculosinyl diphosphate 3, indicating that the Rv3378c enzyme catalyzed the nucleophilic addition of a water molecule after the release of a diphosphate moiety. The three enzymatic products 2, 5a, and 5b were produced irrespective of the N- and C-terminal His-tagged Rv3378c enzymes, and of the maltose-binding protein fusion enzyme; the product distribution ratio was identical between the enzymes as 1:1 for 2:5, and 1:3 for 5a:5b. The successful separation of 5a and 5b by a chiral HPLC column provided the first complete assignments of ¹H- and ¹³C-NMR data for 5a and 5b. The enzymatic mechanism for producing 2, 5a, and 5b is proposed here, and the optimal catalytic conditions and kinetic parameters, in addition to the divalent metal effects, are described. Site-directed mutagenesis of Asp into Asn, targeted at the DDXXD motif, resulted in significantly decreased enzymatic activity.

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Natural terpenoids have elaborate structures and various bioactivities, making difficult their synthesis and labeling with isotopes. We report here the enzymatic total synthesis of plant hormone gibberellins (GAs) with recombinant biosynthetic enzymes from stable isotope-labeled acetate. Mevalonate (MVA) is a key intermediate for the terpenoid biosynthetic pathway. ¹³C-MVA was synthesized from ¹³C-acetate via acetyl-CoA, using four enzymes or fermentation with a MVA-secreted yeast. The diterpene hydrocarbon, ent-kaurene, was synthesized from ¹³C-acetate and ¹³C-MVA with ten and six recombinant enzymes in one test tube, respectively. Four recombinant enzymes, P450 monooxygenases and soluble dioxygenases involved in the GA₄ biosynthesis from ent-kaurene via GA₁₂ were prepared in yeast and Escherichia coli. All intermediates and the final product GA₄ were uniformly labeled with ¹³C without dilution by natural abundance when [U-¹³C₂] acetate was used. The ¹³C-NMR and MS data for [U-¹³C₂₀] ent-kaurene confirmed ¹³C-¹³C coupling, and no dilution with the ¹²C atom was observed.

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Dipsaci Radix is the dried root of Dipsacus asper Wall. It has been used in Korean herbal medicine to treat bone fractures. In this study, we examined the effect of the dichloromethane fraction of Dipsaci Radix (DR_DM) on the osteoblastic differentiation of human alveolar bone marrow-derived MSCs (ABM-MSCs). The ABM-MSCs were isolated from healthy subjects and cultured in vitro, followed by phenotypic characterization. They showed a fibroblast-like morphology and expressed CD29, CD44, CD73, and CD105, but not CD34. Calcified nodules were generated in response to both dexamethasone (DEX) and DR_DM. There was a significant increase in the alkaline phosphatase (ALP) activity and protein expression of bone sialoprotein (BSP) and osteocalcin (OC) in response to DEX and DR_DM as compared to control. These results provide evidence for the osteogenic potential of cultured ABM-MSCs in response to DR_DM. Also, an active single compound was additionally isolated from DR_DM. The single compound (hederagenin 3-O-(2-O-acetyl)-α-L-arabinopyranoside) also significantly increased ALP activity and the level of protein expression of BSP and OC. These results highlight the possible clinical applications of DR_DM and hederagenin 3-O-(2-O-acetyl)-α-L-arabinopyranoside in bone regeneration.

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To understand better the host defense mechanisms of mollusks against pathogens, we examined the anti-microbial activity of mucus from the giant African snail Achatina fulica. Hemagglutination activity of the mucus secreted by the integument of snails inoculated with Escherichia coli was observed to increase and to cause hemagglutination of rabbit red blood cells. Purification of the snail mucus lectin by sequential column chromatography revealed that the relative molecular mass of the lectin was 350 kDa. The hemagglutination activity of the lectin was Ca²⁺-dependent and was inhibited by galactose. Growth arrest tests showed that the lectin did not inhibit bacterial growth, but did induce agglutination of gram-positive and gram-negative bacteria. Tissue distribution analyses using a polyclonal antibody revealed that the lectin was expressed in the tissues of the mantle collar. The lectin isolated from the mucus of the snail appeared to contribute to its innate immunity.

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Rhodococcus jostii RHA1 is a polychlorinated biphenyl degrader. Multi-component biphenyl 2,3-dioxygenase (BphA) genes of RHA1 encode large and small subunits of oxygenase component and ferredoxin and reductase components. They did not express enzyme activity in Escherichia coli. To obtain BphA activity in E. coli, hybrid BphA gene derivatives were constructed by replacing ferredoxin and/or reductase component genes of RHA1 with those of Pseudomonas pseudoalcaligenes KF707. The results obtained indicate a lack of catalytic activity of the RHA1 ferredoxin component gene, bphAc in E. coli. To determine the cause of inability of RHA1 bphAc to express in E. coli, the bphAc gene was introduced into Rosetta (DE3) pLacI, which has extra tRNA genes for rare codons in E. coli. The resulting strain abundantly produced the bphAc product, and showed activity. These results suggest that codon usage bias is involved in inability of RHA1 bphAc to express its catalytic activity in E. coli.

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A cytidine 5′-monophospho-N-acetylneuraminic acid (CMP-Neu5Ac) synthetase was found in a crude extract prepared from Photobacterium leiognathi JT-SHIZ-145, a marine bacterium that also produces a β-galactoside α2,6-sialyltransferase. The CMP-Neu5Ac synthetase was purified from the crude extract of the cells by a combination of anion-exchange and gel filtration column chromatography. The purified enzyme migrated as a single band (60 kDa) on sodium dodecylsulfate–polyacrylamide gel electrophoresis. The activity of the enzyme was maximal at 35 °C at pH 9.0, and the synthetase required Mg²⁺ for activity. Although these properties are similar to those of other CMP-Neu5Ac synthetases isolated from bacteria, this synthetase produced not only CMP-Neu5Ac from cytidine triphosphate and Neu5Ac, but also CMP-N-glycolylneuraminic acid from cytidine triphosphate and N-glycolylneuraminic acid, unlike CMP-Neu5Ac synthetase purified from Escherichia coli.

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MicroRNAs (miRNAs) are small non-coding RNAs that play important roles in a variety of biological processes. Studies of miRNAs in mammals suggest that many are involved in lipid metabolism and adipocyte differentiation, but little is known about miRNA expression profiles during chicken adipogenesis. In this study, the Solexa sequencing approach was used to sequence a small RNA library prepared from Arbor Acres broiler pre-adipocytes, and more than 10⁶ short sequence reads were obtained. From these, 159 known chicken miRNAs and 63 novel miRNAs were identified using a bioinformatics approach. Fifty-nine of these miRNA genes were further organized into 27 compact miRNA genomic clusters, and 34 new chicken mirtrons were also discovered, among which there were 27 mirtron candidates. These findings should serve as a foundation for future research on the functional roles of miRNAs in chicken adipocyte differentiation.

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A new galectin was characterized in the Amethyst deceiver mushroom Laccaria amethystina. The complete amino acid (AA) sequence of the lectin, which exhibited β-galactoside specificity, was deduced from its peptide sequences. The AA sequence of L. amethystina galectin (LAG) showed high homology with those of the same genus, at 75.6% identity to Laccaria bicolor, and 35.5–65.0% to galectins of Agrocybe spp. and Coprinopsis cinerea. The AA sequence of LAG contained all but one conserved residue known to be involved in β-galactoside binding, with His at the position 57 residue replaced by Thr in LAG. Analysis of binding specificity by hemagglutination inhibition assay and enzyme-linked lectin-sorbent assay revealed high specificity of LAG towards O-glycoproteins.

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Humic acids (HAs) have positive effects on plant physiology, but the molecular mechanisms underlying these events are only partially understood. The induction of root growth and emission of lateral roots (LRs) promoted by exogenous auxin is a natural phenomenon. Exogenous auxins are also associated with HA. Gas nitric oxide (NO) is a secondary messenger produced endogenously in plants. It is associated with metabolic events dependent on auxin. With the application of auxin, NO production is significantly increased, resulting in positive effects on plant physiology. Thus it is possible to evaluate the beneficial effects of the application of HA as an effect of auxin. To investigate the effects of HA the parameters of root growth, Zea mays was studied by evaluating the application of 3 mM C L⁻¹ of HA extracted from Oxisol and 100 μM SNP (sodium nitroprusside) and the NO donor, subject to two N–NO₃⁻, high dose (5.0 mM N–NO₃⁻) and low dose (5.0 mM N–NO₃⁻). Treatments with HA and NO were positively increased, regardless of the N–NO₃⁻ taken, as assessed by fresh weight and dry root, issue of LRs. The effects were more pronounced in the treatment with a lower dose of N–NO₃⁻. Detection of reactive oxygen species (ROS) in vivo and catalase activity were evaluated; these tests were associated with root growth. Under application of the bioactive substances tested, detection of ROS and catalase activity increased, especially in treatments with lower doses of N–NO₃⁻. The results of this experiment indicate that the effects of HA are dependent on ROS generation, which act as a messenger that induces root growth and the emission of LRs.

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Membrane proteins in the Golgi apparatus play important roles in biological functions, predominantly as catalysts related to post-translational modification of protein oligosaccharides. We succeeded in extracting the characteristics of Golgi type II membrane proteins computationally by comparison with those of Golgi no retention proteins, which are mainly localized in the plasma membrane. Golgi type II membrane proteins were detected by combining hydropathy alignment and a position-specific score matrix of the amino acid propensities around the transmembrane region. We achieved 96.2% sensitivity, 93.5% specificity, and a 0.949 success rate in a self-consistency test. In a 5-fold cross-validation test, 88.0% sensitivity, 85.5% specificity, and a 0.867 success rate were achieved.

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The role of amino acid residues in the enzymatic activity of carboxylesterase from Arthrobacter globiformis was analyzed by diisopropyl fluorophosphate (DFP) labeling and site-directed mutagenesis. The electrospray ionization mass spectrometric (ESI-MS) analysis of the esterase, covalently labeled by DFP, showed stoichiometric incorporation of the inhibitor into the enzyme. The further comparison of endopeptidase-digested fragments between native and DFP-labeled esterase by fast atom bombardment mass spectrometric (FAB-MS) analysis as well as site-directed mutagenesis indicated that Ser59 in the consensus sequence Ser-X-X-Lys, which is conserved exclusively in penicillin-binding proteins and some esterases, served as a catalytic nucleophile. In addition, the results obtained from analysis of the mutants at position 62 suggested the importance of the basic amino acid side chain at this position, and suggested the significance of this residue acting directly as a general base rather than its involvement in the maintenance of the optimum hydrogen-bonding network at the active site.

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Carapichea ipecacuanha produces various emetine-type alkaloids, known as ipecac alkaloids, which have long been used as expectorants, emetics, and amebicides. In this study, we isolated an O-methyltransferase cDNA from this medicinal plant. The encoded protein (CiOMT1) showed 98% sequence identity to IpeOMT2, which catalyzes the 7′-O-methylation of 7′-O-demethylcephaeline to form cephaeline at the penultimate step of emetine biosynthesis (Nomura and Kutchan, J. Biol. Chem., 285, 7722–7738 (2010)). Recombinant CiOMT1 showed both 7′-O-methylation and 6′-O-methylation activities at the last two steps of emetine biosynthesis. This indicates that small differences in amino acid residues are responsible for distinct regional methylation specificities between IpeOMT2 and CiOMT1, and that CiOMT1 might contribute to two sequential O-methylation steps from 7′-O-demethylcephaeline to emetine.

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Rapid growth of the submerged shoots of deepwater rice is essential for survival during the rainy season. We investigated changes in the expression of vacuolar H⁺-ATPase (V-ATPase), H⁺-pyrophosphatase (V-PPase), and aquaporins under submerged conditions. The amounts of vacuolar proton pumps, which support the active transport of ions into the vacuoles, were maintained on a membrane protein basis in the developing vacuoles. Among the six isogenes of V-PPase, OsVHP1;3 was markedly enhanced by submersion. The gene expression of efficient water channels, OsTIP1;1, OsTIP2;2, OsPIP1;1, OsPIP2;1, and OsPIP2;2, was markedly enhanced by submersion. The increase in aquaporin expression might support quick elongation of internodes. The mRNA levels of OsNIP2;2 and OsNIP3;1, which transport silicic and boric acids respectively, clearly decreased. The present study indicates that internodes of deepwater rice upregulate vacuolar proton pumps and water channel aquaporins and downregulate aquaporins that allow permeation of the substrates that suppress internode growth.

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Since certain missense mutations in the N-terminal part of filamin A (FLNA) cause inherited skeletal malformation, we screened for proteins that bind to this part of FLNA. We identified two nuclear proteins that are specifically associated with the N-terminal region of FLNA. This suggests more extensive nuclear function of filamin than expected.

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We cloned the genes encoding the two distinct extracellular halotolerant proteases of Bacillus subtilis FP-133 Expro-I and Expro-II, which were classified as alkaline serine and neutral proteases respectively. Three-dimensional modeling suggested that acidic and polar amino acid residues located on the surface stabilize protein structure in the presence of relatively high NaCl concentrations.

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In this study, we analyzed structural features of the N-glycans linked to glycoproteins expressed in various edible beans to identify excellent sources of useful N-glycans and N-glycopeptides. Structural analysis of N-glycans of the glycopeptides prepared from the pepsin digests of bean powder that the useful high-mannose type N-glycans occur predominantly in Phaseolus and Vigna beans; tora bean for Man₉GlcNAc₂-Asn, dainagon bean for Man₈GlcNAc₂-Asn, and azuki bean for Man₇GlcNAc₂-Asn.

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Cysteinyl dipeptidase from Aspergillus oryzae (CdpA) was produced in Escherichia coli and purified. The enzyme showed activity specific toward cysteine-containing dipeptides, but its substrate specificity was distinct from those of other cysteinyl dipeptidases of the M20 family. It was optimally active at pH 7–8 and stable at pH 6–9 and at up to 40 °C.

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We isolated temperature-sensitive mutants of the Escherichia coli bamD gene, which is essential for the assembly of β-barrel outer membrane proteins. As their multicopy suppressor, we identified a novel yiaD gene encoding a putative lipoprotein, YiaD. Mutations of its OmpA domain, which is required for interaction with peptidoglycan, affected suppression, suggesting that interaction with peptidoglycan is important to YiaD function.

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The cytoplasmic domain of the medicinal mushroom Cordyceps militaris β-1,3-glucan synthase catalytic subunit Fks1 was expressed as a fusion protein with an N-terminal hexahistidine tag and glutathione S-transferase in an Escherichia coli cell-free translation system, and was assayed for binding specificity. The recombinant cytoplasmic domain bound specifically to UDP-agarose and lichenan (β-glucan), but not to ADP-agarose, GDP-agarose, or other carbohydrates.

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In this study, we cloned the gene encoding 5-aminolevulinic acid synthase (ALAS) from the hyper-lignin-degrading fungus Phanerochaete sordida YK-624. The deduced amino acid sequence showed highest identity (93.0%) to ALAS of P. chrysosporium. Expression of the gene encoding ALAS, which we named aas, corresponded temporally with the expression and activity of manganese peroxidase.

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The reactive oxygen species generated by an aqueous extract of the particulate phase of cigarette smoke were evaluated by an electron spin resonance (ESR) analysis, using spin-trapping agents, and by comparing with model reaction systems. The ESR signals of DMPO-OH were detected from the extract by using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). These signals were eliminated by adding superoxide dismutase, but hardly by catalase. These responses of the ESR signals to the scavengers were similar to those of a hypoxanthine-xanthine oxidase system. The results indicate that the signals of DMPO-OH from the extract were derived from a reaction product of DMPO with superoxide anion radicals and clarify the mechanism by which the extract generated superoxide anion radicals.

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The water-soluble fraction of kale (Brassica oleracea L. var. acephala DC.) had immunoglobulin (Ig) production stimulating activity in human hybridoma HB4C5 cells and human peripheral blood lymphocytes. The biochemical and physical properties of the main active substance in kale were found to be a heat-stable protein with a molecular weight higher than 50 kDa. The Ig production-stimulating factors were assumed to act on the translational and/or secreting processes of Igs. This Ig production-stimulating effect was also observed in lymphocytes from the mesenteric lymph node and Peyer’s patches of mice that had been administered with the kale extract for 14 d. The partially purified kale extract was analyzed by LC-ESI-MS/MS, the result indicating ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) as an active substance. Rubisco from spinach indeed exhibited Ig production-stimulating activity in HB4C5 cells. These findings provide another beneficial aspect of kale as a health-promoting foodstuff.

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Enhancing energy expenditure and reducing energy intake are both crucial for weight control. Capsinoids, which are non-pungent capsaicin analogs, are known to suppress body fat accumulation and reduce body weight by enhancing energy expenditure in both mice and humans. However, it is poorly understood whether the suppression of body fat accumulation by capsinoids has an advantage over dietary restriction. This study shows that the oxygen consumption was increased in mice administered with capsinoids but not in dietary-restricted mice, although there was a similar suppression of body fat accumulation in both groups. The weight rebound was more notable in the dietary-restricted mice than in the mice administered with capsinoids. These results indicate that suppressing body fat accumulation by capsinoids was more beneficial than a restricted diet for maintaining body weight.

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Human serum albumin (HSA) contributes to the stabilization of (−)-epigallocatechin gallate (EGCg) in serum. We characterize in the present study the mechanisms for preventing EGCg oxidation by HSA. EGCg was stable in human serum or buffers with HSA, but (−)-epigallocatechin (EGC) was unstable. We show by comparing EGCg and EGC in a neutral buffer that EGCg had a higher binding affinity than EGC. This indicates that the galloyl moiety participated in the interaction of EGCg with HSA and that this interaction was of critical importance in preventing EGCg oxidation. The binding affinity of EGCg for HSA and protein carbonyl formation in HSA were enhanced in an alkaline buffer. These results suggest the reversible covalent modification of EGCg via Schiff-base formation, and that the immobilization of EGCg to HSA, through the formation of a stable complex, prevented the polymerization and decomposition of EGCg in human serum.

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A new biological activity of 6-(methylsulfinyl)hexyl isothiocyanate derived from Wasabia japonica was discovered as an inhibitor of glycogen synthase kinase-3β. The most potent isothiocyanate, 9-(methylsulfinyl)hexyl isothiocyanate, inhibited glycogen synthase kinase-3β at a K_i value of 10.5 μM and showed ATP competitive inhibition. The structure-activity relationship revealed an inhibitory potency of methylsulfinyl isothiocyanate dependent on the alkyl chain length and the sulfoxide, sulfone, and/or the isothiocyanate moiety.

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We tested the effect of oral administration of fermented sake lees with lactic acid bacteria (FESLAB) on a murine model of allergic rhinitis upon immunization and nasal sensitization with ovalbumin (OVA). We used Lactobacillus paracasei NPSRIk-4 (isolated from sake lees), and L. brevis NPSRIv-8 (from fermented milk) as starter strains to produce the FESLAB. Oral FESLAB administration resulted in the development of significantly fewer sneezing symptoms than those seen in sham control animals given sterile water. We also found that FESLAB suppressed the allergen-induced degranulation of RBL2H3 rat basophilic leukemia cells.

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We attempted to improve the bioavailability of green tea catechins by using food ingredients. The catechin bioavailability of a green tea extract administered to mice was significantly (p<0.05) increased by supplementing with steamed rice. This enhanced bioavailability was due to the increased concentration of plasma non-gallated catechins, especially epigallocatechin (EGC).

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β-Lactoglobulin (BLG), a major allergen of cow’s milk, was conjugated with the N-hydroxysuccinimide ester of the amylose-glycylglycine adduct (AG-ONSu) to reduce its immunogenicity, and the biochemical and immunological properties of the resulting conjugate (AG-BLG) were studied. The conjugate was prepared by modifying BLG with AG-ONSu, and was purified in a Sephadex G-100 column. The analytical data for AG-BLG indicated that 10.5 moles of AG-ONSu, with a mean molecular weight of 2,800, was covalently attached to the amino groups of the BLG molecule. Conjugation with AG-ONSu greatly decreased the reactivity of BLG with anti-BLG polyclonal antibodies owing to its shielding action for epitopes on the protein’s surface. These findings suggest that AG-ONSu can be used advantageously to suppress the hypersensitivity mediated by IgG antibodies in milk allergy.

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The uptake activity ratio for AMP, ADP, and ATP in mutant (T-1) cells of Escherichia coli W, deficient in de novo purine biosynthesis at a point between IMP and 5-aminoimidazole-4-carboxiamide-1-β-D-ribofuranoside (AICAR), was 1:0.43:0.19. This ratio was approximately equal to the 5′-nucleotidase activity ratio in E. coli W cells. The order of inhibitory effect on [2-³H]ADP uptake by T-1 cells was adenine > adenosine > AMP > ATP. About 2-fold more radioactive purine bases than purine nucleosides were detected in the cytoplasm after 5 min in an experiment with [8-¹⁴C]AMP and T-1 cells. Uptake of [2-³H]adenosine in T-1 cells was inhibited by inosine, but not in mutant (Ad-3) cells of E. coli W, which lacked adenosine deaminase and adenylosuccinate lyase. These experiments suggest that AMP, ADP, and ATP are converted mainly to adenine and hypoxanthine via adenosine and inosine before uptake into the cytoplasm by E. coli W cells.

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Rhodococcus erythropolis N9T-4 shows extremely oligotrophic growth requiring atmospheric CO₂ without any additional carbon or energy source. We performed a gene expression analysis of the oxidoreductases, which are involved in methanol metabolism, under various growth and induction conditions in N9T-4. A real-time PCR analysis revealed that the genes encoding NAD-dependent formaldehyde dehydrogenase (nFADH) and N,N′-dimethyl-4-nitrosoaniline-dependent methanol dehydrogenase (MDH) were strongly expressed under the oligotrophic conditions at levels of 20–100 fold those under heterotrophic conditions, in which n-tetradecane was used as the sole carbon source, while glucose did not affect the gene expression pattern in a minimum medium. The genes encoding mycothiol-dependent formaldehyde dehydrogenase (mFADH) and formate dehydrogenase were not induced under oligotrophic conditions, although mFADH expression was observed when formaldehyde was added to the induction medium. These results suggest that N9T-4 had three distinct formaldehyde oxidation systems, and that MDH and nFADH were the key enzymes in its oligotrophic growth.

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The cDNA encoding a putative xylose reductase (xyrA) from Aspergillus oryzae was cloned and coexpressed in the yeast Saccharomyces cerevisiae with A. oryzae xylitol dehydrogenase cDNA (xdhA). XyrA exhibited NADPH-dependent xylose reductase activity. The S. cerevisiae strain, overexpressing the xyrA, xdhA, endogenous XKS1, and TAL1 genes, grew on xylose as sole carbon source, and produced ethanol.

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We investigated the effects of hypergravity on gene expression in Escherichia coli. Analysis of gene expression using green fluorescence protein reporter showed downregulation at 50,000g, as found for OmpW, which was one of the gravity-induced proteins. Real time-PCR analysis showed normal transcription even at 50,000g. These results suggest that hypergravity inhibited the translation process in gene expression.

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Five carboxin-resistant mutants from Aspergillus oryzae were characterized by the sensitivities of their mycelial growth and succinate dehydrogenase (SDH) activity to carboxin and three related fungicides. Despite a significant resistance to carboxin, exhibited by all the mutants, their patterns of sensitivity to the other fungicides was distinct. This provides clues to the molecular interaction between SDH and these fungicides.

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