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Abstract
The effect of acacetin isolated from Scoparia dulcis and several related flavonoids on herpes simplex virus type 1 (HSV-1) was studied in vitro by the method of plaque yield reduction. Among these compounds, acacetin was shown to be the most potent agent and caused dose-dependent inhibition of virus replication. Acacetin had a weak virucidal activity at higher concentrations. Analysis of early events following infection showed that attachment of the virus to host cells and penetration were unaffected by acacetin. Acacetin was found to exert strong inhibition of protein synthesis in virus-infected cells but not in uninfected cells. The transcription of immediate-early genes and translation of their transcripts were in particular almost stopped by acacetin even at a lower concentration. These selective effects can be attributed mainly to the antiviral activity of acacetin.
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Affiliation(s)
- K. Hayashi
- School of Medicine, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930–01, Japan
| | - T. Hayashi
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930–01, Japan
| | - M. Arisawa
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930–01, Japan
| | - N. Morita
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930–01, Japan
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2
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Arisawa M, Hayashi K, Nikaido T, Koike K, Fujita D, Nunomura N, Tanaka M, Sasaki T. Screening of Some Marine Organism Extracts for cAMP Phosphodiesterase Inhibition, Cytotoxicity, and Antiviral Activity against HSV-1. ACTA ACUST UNITED AC 2008. [DOI: 10.1076/phbi.35.1.6.13265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- M Arisawa
- Laboratory of Herbal Garden, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-01, Japan
| | - K Hayashi
- Department of Virology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-01, Japan
| | - T Nikaido
- Department of Pharmacognosy, School of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274, Japan
| | - K Koike
- Laboratory of Herbal Garden, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-01, Japan
| | - D Fujita
- Toyama Prefectural Fisheries Research Institute, 364 Takatsuka, Namerikawa, Toyama 936, Japan
| | - N Nunomura
- Toyama Science Museum, 1-8-31 Nishinakanomachi, Toyama 939, Japan
| | - M Tanaka
- Department of Experimental Therapeutics, Cancer Research Institute, Kanazawa University,13-1 Takaramachi, Kanazawa 920, Japan
| | - T Sasaki
- Laboratory of Herbal Garden, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-01, Japan
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3
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Kurosaki F, Yamashita A, Arisawa M. Determination of Ca(2+) influx across plant plasma membrane with sealed vesicles reoriented by Brij 58. Anal Biochem 2001; 299:266-8. [PMID: 11730354 DOI: 10.1006/abio.2001.5426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- F Kurosaki
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, Toyama 930-0194, Japan
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4
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Ishii R, Horie M, Saito K, Arisawa M, Kitanaka S. Inhibitory effects of phloroglucinol derivatives from Mallotus japonicus on nitric oxide production by a murine macrophage-like cell line, RAW 264.7, activated by lipopolysaccharide and interferon-gamma. Biochim Biophys Acta 2001; 1568:74-82. [PMID: 11731088 DOI: 10.1016/s0304-4165(01)00203-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
An aqueous acetone extract of the pericarps of Mallotus japonicus (MJE) inhibited nitric oxide (NO) production by a murine macrophage-like cell line, RAW 264.7, which was activated by lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). Seven phloroglucinol derivatives isolated from MJE exhibited inhibitory activity against NO production. Among these phloroglucinol derivatives, isomallotochromanol exhibited strong inhibitory activity toward NO production, exhibiting an IC(50) of 10.7 microM. MJE and the phloroglucinol derivatives significantly reduced both the induction of inducible nitric oxide synthase (iNOS) protein and iNOS mRNA expression. NO production by macrophages preactivated with LPS and IFN-gamma for 16 h was also inhibited by MJE and the phloroglucinol derivatives. Furthermore, MJE and the derivatives directly affected the conversion of L-[(14)C]arginine to L-[(14)C]citrulline by the cell extract. These results suggest that MJE and the phloroglucinol derivatives have the pharmacological ability to suppress NO production by activated macrophages. They inhibited NO production by two mechanisms: reduction of iNOS protein induction and inhibition of enzyme activity.
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Affiliation(s)
- R Ishii
- Saitama Instiute of Public Health, Japan
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5
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Nakayama H, Nakayama N, Arisawa M, Aoki Y. In vitro and in vivo effects of 14alpha-demethylase (ERG11) depletion in Candida glabrata. Antimicrob Agents Chemother 2001; 45:3037-45. [PMID: 11600353 PMCID: PMC90779 DOI: 10.1128/aac.45.11.3037-3045.2001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2000] [Accepted: 08/14/2001] [Indexed: 11/20/2022] Open
Abstract
Sterol 14alpha-demethylase (ERG11) is the target enzyme of azole antifungals that are widely used for the treatment of fungal infections. Candida glabrata is known to be less susceptible to fluconazole than most Candida albicans strains, and the incidence of C. glabrata infection has been increasing mostly in conjunction with the use of azole antifungals. Recently, it has been reported that C. glabrata can rescue the defect of ergosterol biosynthesis by incorporating cholesterol from serum. To explore the effect of inactivating Erg11p in C. glabrata, we generated mutant strains in which the ERG11 gene was placed under the control of tetracycline-regulatable promoters. In these mutants, expression of the ERG11 gene can be repressed by doxycycline (DOX). All mutants showed a growth defect in the presence of DOX. The numbers of CFU of the mutants were lowered by only 1/10 with DOX treatment. In these mutants, accumulation of 4,14-dimethylzymosterol, which differs from an accumulated abnormal sterol detected in C. albicans and Saccharomyces cerevisiae treated with fluconazole, was observed by DOX treatment. Although such phenotypes were also observed in serum-containing media by DOX treatment, they were alleviated. Furthermore, the mutant could grow in DOX-treated mice without a severe reduction in the number of cells. Thus, depleting the expression of the ERG11 gene lowered the number of CFU by only 1/10 due to the accumulation of 4,14-demethylzymosterol in vitro, and it did not result in the defective growth of fungal cells in mice. These results suggested that Erg11p is not an ideal target molecule of antifungals for C. glabrata.
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Affiliation(s)
- H Nakayama
- Department of Mycology, Nippon Roche K. K. Research Center, Kamakura, Kanagawa 247-8530, Japan.
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6
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Kurosaki F, Togashi K, Arisawa M. Regulation of catalytic activity of a multifunctional polyketide biosynthetic enzyme, 6-hydroxymellein synthase, by interaction between NADPH and phenylglyoxal-sensitive amino acid residue at the reaction center. Biochim Biophys Acta 2001; 1549:51-60. [PMID: 11566368 DOI: 10.1016/s0167-4838(01)00243-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Treatment of 6-hydroxymellein synthase, a multifunctional polyketide biosynthetic enzyme in carrot cells, with phenylglyoxal yielded a chemically modified protein in which approximately two moles of the reagent were covalently attached to each subunit of the enzyme. Only NADH- but not NADPH-associated form of native 6-hydroxymellein synthase was inhibited by cerulenin; however, the NADPH-synthase complex lost the insensitivity by the chemical modification of the enzyme protein with phenylglyoxal. Appreciable differences in K(m) values observed between the NADPH- and NADH-associated enzymes were greatly reduced by the treatment with phenylglyoxal. Although the catalytic activity of the NADPH-associated synthase was enhanced by the addition of free CoA, the compound exhibited a significant inhibitory activity to the phenylglyoxal-modified enzyme. A marked deuterium isotope effect in the catalytic reaction of the native synthase-NADPH complex was appreciably decreased in the chemically modified enzyme. These results strongly suggest that an electrostatic interaction between the phosphate group attached to the 2'-position of adenosyl moiety of NADPH and the phenylglyoxal-sensitive amino acid residue, probably arginine, at the reaction center of 6-hydroxymellein synthase regulates several biochemical properties of this multifunctional enzyme.
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Affiliation(s)
- F Kurosaki
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, Toyama 930-0194, Japan.
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7
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Asano N, Yokoyama K, Sakurai M, Ikeda K, Kizu H, Kato A, Arisawa M, Höke D, Dräger B, Watson AA, Nash RJ. Dihydroxynortropane alkaloids from calystegine-producing plants. Phytochemistry 2001; 57:721-6. [PMID: 11397439 DOI: 10.1016/s0031-9422(01)00131-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Three dihydroxynortropanes, 2alpha,7beta-dihydroxynortropane, 2alpha,3beta-dihydroxynortropane, and 3alpha,7beta-dihydroxynortropane, were isolated from calystegine-producing plants in the families Convolvulaceae and Solanaceae. 2alpha,7beta-Dihydroxynortropane was isolated from six species in the Convolvulaceae whereas only Calystegia soldanella contained it and 2alpha,3beta-dihydroxynortropane. Although neither of these were detectable in three species tested in the Solanaceae, 3alpha,7beta-dihydroxynortropane was, however, isolated from Duboisia leichhardtii.
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Affiliation(s)
- N Asano
- Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3 Kanagawa-machi, Kanazawa 920-1181, Japan.
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8
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Kurosaki F, Yamashita A, Arisawa M. Involvement of GTP-binding protein in the induction of phytoalexin biosynthesis in cultured carrot cells. Plant Sci 2001; 161:273-278. [PMID: 11448758 DOI: 10.1016/s0168-9452(01)00407-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Biosynthetic activity of carrot phytoalexin 6-methoxymellen was induced in cell suspension culture by the treatment with oligogalacturonide elicitor; however, the elicitor-induced activity appreciably reduced in the presence of suramin, a potent inhibitor of GTP-binding proteins. In contrast, addition of G-protein activators, such as mastoparan or GTP-gamma-S, to carrot cell culture triggered 6-methoxymellein production even in the absence of uronide elicitor. An appreciable GTPase activity was found in purified plasma membrane of cultured carrot cells, and the hydrolytic activity was significantly increased by the addition of elicitor. Carrot plasma membrane was capable of associating with GTP-gamma-S, and the binding ability was markedly increased in the presence of elicitor. However, the binding activity markedly decreased when the membrane preparation was pre-incubated with GTP but not with ATP. These observations strongly suggest that a certain GTP-binding protein located at plasma membrane of cultured carrot cells plays an important role in the oligogalacturonide elicitor-induced 6-methoxymellein production.
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Affiliation(s)
- F Kurosaki
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, 930-0194, Toyama, Japan
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9
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Iwata Y, Arisawa M, Hamada R, Kita Y, Mizutani MY, Tomioka N, Itai A, Miyamoto S. Discovery of Novel Aldose Reductase Inhibitors Using a Protein Structure-Based Approach: 3D-Database Search Followed by Design and Synthesis. J Med Chem 2001; 44:1718-28. [PMID: 11356107 DOI: 10.1021/jm000483h] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aldose reductase (AR) has been implicated in the etiology of diabetic complications. Due to the limited number of currently available drugs for the treatment of diabetic complications, we have carried out structure-based drug design and synthesis in an attempt to find new types of AR inhibitors. With the ADAM&EVE program, a three-dimensional database (ACD3D) was searched using the ligand binding site of the AR crystal structure. Out of 179 compounds selected through this search followed by visual inspection, 36 compounds were purchased and subjected to a biological assay. Ten compounds showed more than 40% inhibition of AR at a 15 microg/mL concentration. In a subsequent lead optimization, a series of analogues of the most active compound were synthesized based on the docking mode derived by ADAM&EVE. Many of these congeners exhibited higher activities compared to the mother compound. Indeed, the most potent, synthesized compound showed an approximately 20-fold increase in inhibitory activity (IC(50) = 0.21 vs 4.3 microM). Furthermore, a hydrophobic subsite was newly inferred, which would be useful for the design of inhibitors with improved affinity for AR.
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Affiliation(s)
- Y Iwata
- Exploratory Chemistry Research Laboratories, Sankyo Co., Ltd., 1-2-58, Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan
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10
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Maebashi K, Niimi M, Kudoh M, Fischer FJ, Makimura K, Niimi K, Piper RJ, Uchida K, Arisawa M, Cannon RD, Yamaguchi H. Mechanisms of fluconazole resistance in Candida albicans isolates from Japanese AIDS patients. J Antimicrob Chemother 2001; 47:527-36. [PMID: 11328762 DOI: 10.1093/jac/47.5.527] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Four Candida albicans isolates, TIMM 3163, TIMM 3164, TIMM 3165 and TIMM 3166, with reduced fluconazole susceptibility were obtained from three AIDS patients in Japan, and the mechanisms of their drug resistance were studied. All isolates showed lower levels of intracellular accumulation of fluconazole than ATCC 10231, a susceptible control strain of C. albicans. Increased amounts of CDR1 and CDR2 mRNA encoding putative ATP binding cassette (ABC) transporters were associated with the azole resistance of all TIMM isolates, apart from TIMM 3164. In addition, increased Cdr1p levels were immunodetected in the cell membrane fractions of all the TIMM strains except for TIMM 3164. Gene amplification was not responsible for CDR1 overexpression and there were no significant differences in the mRNA levels of CDR3 or CDR4 (ABC transporters) in the azole-susceptible and -resistant cells. CaMDR1 (a major facilitator superfamily) gene expression was not observed in any of the resistant isolates or the control strain. These results suggest that energy-dependent drug efflux associated with increased expression of CDR1 and CDR2 is involved in the fluconazole resistance mechanisms in two of the four isolates, TIMM 3165 and TIMM 3166. TIMM 3164 demonstrated energy-dependent drug efflux without overexpression of CDR1-4 or CaMDR1, indicating that some other pump may be operating. Despite showing low levels of drug efflux and overexpression of CDR1 and CDR2, efflux in TIMM 3163 was not energy dependent, suggesting that the expressed Cdr1p non-functional Cdr1p and that other resistance mechanisms may operate in this strain.
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Affiliation(s)
- K Maebashi
- Teikyo University Institute of Medical Mycology, 359 Otsuka, Hachioji, Tokyo 192-0395, Japan.
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11
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Arisawa M, Akamatsu K, Yamaguchi M. GaCl3-promoted ethenylation of silylated beta-dicarbonyl compound with silylethyne. Synthesis of ethenylmalonate. Org Lett 2001; 3:789-90. [PMID: 11259063 DOI: 10.1021/ol015583b] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text]. In the presence of GaCl3, silyl enol ethers derived from alpha-substituted beta-ketoesters or malonates are ethenylated at the alpha-carbon atom with trimethylsilylethyne in high yields. Ethenylmalonates can also be synthesized by this method.
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Affiliation(s)
- M Arisawa
- Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan
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12
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Arisawa M, Yamaguchi M. Addition reaction of dialkyl disulfides to terminal alkynes catalyzed by a rhodium complex and trifluoromethanesulfonic acid. Org Lett 2001; 3:763-4. [PMID: 11259056 DOI: 10.1021/ol015521l] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text]. Addition of dialkyl disulfides to terminal alkynes is catalyzed by a rhodium-phosphine complex and trifluoromethanesulfonic acid giving (Z)-bis(alkylthio)olefins stereoselectively.
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Affiliation(s)
- M Arisawa
- Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan
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13
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Abstract
[figure: see text] Beckmann rearrangement of oxime is catalyzed by [RhCl(cod)]2, trifluoromethanesulfonic acid, and tris(p-tolyl)phosphine in refluxing dichloroethane, giving the corresponding amide in good yield. Product/acid ratios of 10:20 can be attained in the reaction of benzophenone oximes.
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Affiliation(s)
- M Arisawa
- Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan
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14
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Arisawa M, Ramesh NG, Nakajima M, Tohma H, Kita Y. Hypervalent iodine(III)-induced intramolecular cyclization of alpha-(aryl)alkyl-beta-dicarbonyl compounds: a convenient synthesis of benzannulated and spirobenzannulated compounds. J Org Chem 2001; 66:59-65. [PMID: 11429930 DOI: 10.1021/jo000953f] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel hypervalent iodine(III)-induced direct intramolecular cyclization of alpha-(aryl)alkyl-beta-dicarbonyl compounds has been described. Both meta- and para-substituted phenol ether derivatives containing acyclic or cyclic 1,3-dicarbonyl moieties at the side chain undergo this reaction in a facile manner. The reactions afford benzannulated and spirobenzannulated compounds that are of biological importance. The reaction is found to be general, mild, and high yielding. The mechanism of the reaction has been shown to involve a cation radical intermediate.
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Affiliation(s)
- M Arisawa
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan
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15
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Kurosaki F, Togashi K, Arisawa M. Role of reducing co-factors in catalytic reactions of 6-hydroxymellein synthase, a multifunctional polyketide biosynthetic enzyme in carrot cells. Plant Sci 2000; 160:113-120. [PMID: 11164583 DOI: 10.1016/s0168-9452(00)00368-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
6-Hydroxymellein (6HM) synthase, a multifunctional polyketide biosynthetic enzyme in carrot cells, is capable of catalyzing the acyl-CoA condensation and the ketoreduction in the presence of the nucleotide reducing co-factors. Although free CoA at high concentrations functioned as the activator of the NADPH-dependent 6HM formation, the compound exhibited an appreciable inhibitory activity toward the reaction mediated by NADH. CoA showed a potent inhibitory activity against substrate entry into the reaction center of the NADH-associated enzyme while, in the presence of NADPH, the compound slightly inhibited the formation of the acylated enzyme. The catalytic rate of the synthase was appreciably decreased when NADPH was replaced by the deuterium-labeled compound, however, the kH/kD value was markedly reduced if NADH and [D]NADH were employed as the reducing co-factors. These results suggest that the phosphate group attached to 2'-position of the adenosyl moiety of NADPH associated with the ketoreducing domain of 6HM synthase plays an important role in the regulation of the enzyme activity.
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Affiliation(s)
- F Kurosaki
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, 930-0194, Toyama, Japan
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16
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Nakayama H, Mio T, Nagahashi S, Kokado M, Arisawa M, Aoki Y. Tetracycline-regulatable system to tightly control gene expression in the pathogenic fungus Candida albicans. Infect Immun 2000; 68:6712-9. [PMID: 11083786 PMCID: PMC97771 DOI: 10.1128/iai.68.12.6712-6719.2000] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Conventional tools for elucidating gene function are relatively scarce in Candida albicans, the most prevalent human fungal pathogen. To this end, we developed a convenient system to control gene expression in C. albicans by the tetracycline-regulatable (TR) promoters. When the sea pansy Renilla reniformis luciferase gene (RLUC1) was placed under the control of this system, doxycycline (DOX) inhibited the luciferase activity almost completely. In the absence of DOX, the RLUC1 gene was induced to express luciferase at a level 400- to 1,000-fold higher than that in the presence of DOX. The same results were obtained in hypha-forming cells. The replacement of N-myristoyltransferase or translation elongation factor 3 promoters with TR promoters conferred a DOX-dependent growth defect in culture media. Furthermore, all the mice infected with these mutants, which are still virulent, survived following DOX administration. Consistently, we observed that the number of these mutant cells recovered from the mouse kidneys was significantly reduced following DOX administration. Thus, this system is useful for investigating gene functions, since this system is able to function in both in vitro and in vivo settings.
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Affiliation(s)
- H Nakayama
- Department of Mycology, Nippon Roche K. K. Research Center, 200 Kajiwara, Kamakura, Kanagawa 247-8530, Japan.
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17
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Sudoh M, Yamazaki T, Masubuchi K, Taniguchi M, Shimma N, Arisawa M, Yamada-Okabe H. Identification of a novel inhibitor specific to the fungal chitin synthase. Inhibition of chitin synthase 1 arrests the cell growth, but inhibition of chitin synthase 1 and 2 is lethal in the pathogenic fungus Candida albicans. J Biol Chem 2000; 275:32901-5. [PMID: 10930406 DOI: 10.1074/jbc.m003634200] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
As in Saccharomyces cerevisiae, the pathogenic fungus Candida albicans harbors three chitin synthases called CaChs1p, CaChs2p, and CaChs3p, which are structurally and functionally analogous to the S. cerevisiae ScChs2p, ScChs1p, and ScChs3p, respectively. In S. cerevisiae, ScCHS1, ScCHS2, and ScCHS3 are all non-essential genes; only the simultaneous disruption of ScCHS2 and ScCHS3 is lethal. The fact that a null mutation of the CaCHS1 is impossible, however, implies that CaCHS1 is required for the viability of C. albicans. To gain more insight into the physiological importance of CaCHS1, we identified and characterized a novel inhibitor that was highly specific to CaChs1p. RO-09-3143 inhibited CaChs1p with a K(i) value of 0.55 nm in a manner that was non-competitive to the substrate UDP-N-acetylglucosamine. RO-09-3143 also hampered the growth of the C. albicans cells with an MIC(50) value of 0.27 microm. In the presence of RO-09-3143, the C. albicans cells failed to form septa and displayed an aberrant morphology, confirming the involvement of the C. albicans Chs1p in septum formation. Although the effect of RO-09-3143 on the wild-type C. albicans was fungistatic, it caused cell death in the cachs2Delta null mutants but not in the cachs3Delta null mutants. Thus, it appears that in C. albicans, inhibition of CaChs1p causes cell growth arrest, but simultaneous inhibition of CaChs1p and CaChs2p is lethal.
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Affiliation(s)
- M Sudoh
- Department of Mycology and Oncology and the Department of Chemistry, Nippon Roche Research Center, Kanagawa 247-8530, Japan
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18
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Arisawa M, Tohma H, Kita Y. [Development of intramolecular oxidative phenolic coupling reactions using hypervalent iodine (III) reagents and their application to the synthesis of Amaryllidaceae alkaloids]. YAKUGAKU ZASSHI 2000; 120:1061-73. [PMID: 11082716 DOI: 10.1248/yakushi1947.120.10_1061] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypervalent iodine (III) reagents nowadays are used extensively in the field of organic chemistry. Especially, phenyliodine (III) diacetate (PIDA) or phenyliodine (III) bis(trifluoroacetate) (PIFA) have received much attention because of their reactivities similar to heavy metal reagents or anodic oxidation, low toxicity, ready availability and easy handling. In the continuous study of our oxidative phenolic coupling reactions using a hypervalent iodine (III) reagents, a versatile synthetic procedure for the galanthamine-type Amaryllidaceae alkaloids was accomplished. The first total synthesis of (+/-)-sanguinine and the total syntheses of (+/-)-galanthamine, (+/-)-narwedine, (+/-)-lycoramine, and (+/-)-norgalanthamine were also successfully carried out.
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Affiliation(s)
- M Arisawa
- Graduate School of Pharmaceutical Sciences, Osaka University, Japan
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19
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Arisawa M, Takahashi M, Takezawa E, Yamaguchi T, Torisawa Y, Nishida A, Nakagawa M. Construction of chiral 1,2-cycloalkanopyrrolidines from L-proline using ring closing metathesis (RCM). Chem Pharm Bull (Tokyo) 2000; 48:1593-6. [PMID: 11045475 DOI: 10.1248/cpb.48.1593] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An efficient synthetic method for the preparation of optically active pyrroloazocine, pyrroloazepine, quinolizidine, indolizidine using ring closing olefin metathesis (RCM) is described.
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Affiliation(s)
- M Arisawa
- Faculty of Pharmaceutical Sciences, Chiba University, Japan
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20
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Terashima H, Yabuki N, Arisawa M, Hamada K, Kitada K. Up-regulation of genes encoding glycosylphosphatidylinositol (GPI)-attached proteins in response to cell wall damage caused by disruption of FKS1 in Saccharomyces cerevisiae. Mol Gen Genet 2000; 264:64-74. [PMID: 11016834 DOI: 10.1007/s004380000285] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
FKS1 and FKS2 encode alternative catalytic subunits of the glucan synthases that are responsible for synthesis of beta-1,3-glucan in the Saccharomyces cerevisiae cell wall. Disruption of FKS1 reduces the glucan content of the cell wall, increases chitin content and activates the expression of CWP1, which encodes a glycosylphosphatidylinositol (GPI)-dependent cell wall protein. These cellular responses have been regarded as compensating for cell wall damage in order to maintain cell wall integrity. Here, we report the identification, by genome-wide screening, of 22 genes that are transcriptionally up-regulated in fks1delta cells. Among them, five genes were found to encode GPI-attached proteins, three of which are covalently associated with the cell wall. Deletion and replacement analysis of the promoter regions identified Rlm1-binding sequences as being responsible for the up-regulation following disruption of FKS1. Using the rlm1delta tetOp-FKS1 strain, in which the expression of FKS1 can be repressed by doxycycline, we examined the requirement for Rlm1 for the transcriptional up-regulation of these five genes. Three of the five genes were not up-regulated by doxycycline, indicating that Rlm1 mediates their up-regulation when FKS1 is inactivated. The remaining two genes were up-regulated by doxycycline, suggesting that a transcription factor other than Rlm1 is involved in their response to disruption of FKS1.
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Affiliation(s)
- H Terashima
- Department of Mycology, Nippon Roche Research Center, Kamakura, Kanagawa, Japan
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21
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Nakayama H, Izuta M, Nakayama N, Arisawa M, Aoki Y. Depletion of the squalene synthase (ERG9) gene does not impair growth of Candida glabrata in mice. Antimicrob Agents Chemother 2000; 44:2411-8. [PMID: 10952588 PMCID: PMC90078 DOI: 10.1128/aac.44.9.2411-2418.2000] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Squalene synthase (farnesyl-diphosphate farnesyltransferase, EC 2.5. 1.21) is the first committed enzyme of the sterol biosynthesis pathway. Inhibitors of this enzyme have been intensively studied as potential antifungal agents. To assess the effect of deactivating squalene synthase on the growth of fungi in mice, we isolated the squalene synthase (ERG9) gene from the pathogenic fungus Candida glabrata and generated strains in which the CgERG9 gene was under the control of the tetracycline-regulatable promoter. Depletion of the ERG9 gene by doxycycline (DOX), a derivative of tetracycline, decreased the cell viability in laboratory media, whereas it did not affect cell growth in mice at all. The growth defect caused by DOX in laboratory media was suppressed by the addition of serum. Analyses of the sterol composition of the restored cells in serum-containing media suggest that the defect of ergosterol biosynthesis can be complemented by the incorporation of exogenous cholesterol into the cells. Thus, deactivation of squalene synthase did not affect fungal growth in mice, presumably because the cells were able to incorporate cholesterol from the serum. These results showed that squalene synthase could not be a suitable target of antifungals for the treatment of C. glabrata infection.
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Affiliation(s)
- H Nakayama
- Department of Mycology, Nippon Roche K. K. Research Center, Kanagawa, Japan.
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22
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Kurosaki F, Togashi K, Arisawa M. Unusual arrangement of catalytic domains in head-to-tail associated homodimer of 6-hydroxymellein synthase, a multifunctional polyketide biosynthetic enzyme. Plant Sci 2000; 157:217-223. [PMID: 10960735 DOI: 10.1016/s0168-9452(00)00286-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
6-Hydroxymellein synthase, a multifunctional polyketide synthetic enzyme in carrot, is organized as a homodimer, and the activity of the synthase was appreciably inhibited upon the specific alkylation of cysteine- and cysteamine-SHs at the reaction center with iodoacetoamide and chloroacetyl-CoA, respectively. Dissociation and stoichiometric recombination of the unmodified and the SH-modified enzyme subunits yielded a combination of unmodified-unmodified, unmodified-modified and modified-modified hybrid dimers that together exhibit 50% activity. In contrast, hybrid dimers obtained by reconstruction of the two modified enzymes showed essentially no catalytic activity. These results suggest that the two subunits of 6-hydroxymellein synthase are aligned in head-to-tail orientation to organize two reaction centers which are comprised of a cysteine and a complementary cysteamine SH group, belonging to and contributed from the same subunit in the homodimer structure.
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Affiliation(s)
- F Kurosaki
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, 930-0194, Toyama, Japan
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23
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Ohta A, Chibana H, Arisawa M, Sudoh M. The VIG9 gene products from the human pathogenic fungi Candida albicans and Candida glabrata encode GDP-mannose pyrophosphorylase. Biochim Biophys Acta 2000; 1475:265-72. [PMID: 10913825 DOI: 10.1016/s0304-4165(00)00075-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have identified two genomic DNA fragments from the human pathogenic fungi, Candida albicans (CaVIG9) and Candida glabrata (CgVIG9) that encode GDP-mannose pyrophosphorylase, a key enzyme for protein glycosylation. The VIG9 homologues of CaVIG9 and CgVIG9 complement an identified protein glycosylation-defective mutation, vig9, of Saccharomyces cerevisiae. The nucleotide sequences of the ORFs, which are 83 and 90% identical to that of the ScVIG9 protein, respectively, showed a predicted gene product homologous to S. cerevisiae GDP-mannose pyrophosphorylase. We examined the enzyme activity of a glutathione S-transferase fusion of each VIG9 gene to synthesize GDP mannose in the cell extracts of a heterologous Escherichia coli expression system. We also developed a method for detecting the enzyme activity using a non-radioactive substrate that would be applicable to high throughput screening.
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Affiliation(s)
- A Ohta
- Department of Mycology, Nippon Roche Research Center, Kamakura, Kanagawa, Japan
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24
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Mio T, Yamada-Okabe T, Arisawa M, Yamada-Okabe H. Functional cloning and mutational analysis of the human cDNA for phosphoacetylglucosamine mutase: identification of the amino acid residues essential for the catalysis. Biochim Biophys Acta 2000; 1492:369-76. [PMID: 11004509 DOI: 10.1016/s0167-4781(00)00120-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In Saccharomyces cerevisiae, phosphoacetylglucosamine mutase is encoded by an essential gene called AGM1. The human AGM1 cDNA (HsAGM1) and the Candida albicans AGM1 gene (CaAGM1) were functionally cloned and characterized by using an S. cerevisiae strain in which the endogenous phosphoacetylglucosamine mutase was depleted. When expressed in Escherichia coli as fusion proteins with glutathione S-transferase, both HsAgm1 and CaAgm1 proteins displayed phosphoacetylglucosamine mutase activities, demonstrating that they indeed specify phosphoacetylglucosamine mutase. Sequence comparison of HsAgm1p with several hexose-phosphate mutases yielded three domains that are highly conserved among phosphoacetylglucosamine mutases and phosphoglucomutases of divergent organisms. Mutations of the conserved amino acids found in these domains, which were designated region I, II, and III, respectively, demonstrated that alanine substitutions for Ser(64) and His(65) in region I, and for Asp(276), Asp(278), and Arg(281) in region II of HsAgm1p severely diminished the enzyme activity and the ability to rescue the S. cerevisiae agm1Delta null mutant. Conservative mutations of His(65) and Asp(276) restored detectable activities, whereas those of Ser(64), Asp(278), and Arg(281) did not. These results indicate that Ser(64), Asp(278), and Arg(281) of HsAgm1p are residues essential for the catalysis. Because Ser(64) corresponds to the phosphorylating serine in the E. coli phosphoglucosamine mutase, it is likely that the activation of HsAgm1p also requires phosphorylation on Ser(64). Furthermore, alanine substitution for Arg(496) in region III significantly increased the K(m) value for N-acetylglucosamine-6-phosphate, demonstrating that Arg(496) serves as a binding site for N-acetylglucosamine-6-phosphate.
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Affiliation(s)
- T Mio
- Department of Mycology, Nippon Roche Research Center, Kamakura, Kanagawa, Japan
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25
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Thomson LM, Bates S, Yamazaki S, Arisawa M, Aoki Y, Gow NA. Functional characterization of the Candida albicans MNT1 mannosyltransferase expressed heterologously in Pichia pastoris. J Biol Chem 2000; 275:18933-8. [PMID: 10766761 DOI: 10.1074/jbc.m909699199] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The alpha1,2-mannosyltransferase gene MNT1 of the human fungal pathogen Candida albicans has been shown to be important for its adherence to various human surfaces and for virulence (Buurman, E. T. , Westwater, C., Hube, B., Brown, A. P. J., Odds, F. C., and Gow, N. A. R. (1998) Proc. Natl. Acad. Sci. U. S. A. 95, 7670-7675). The CaMnt1p is a type II membrane protein, which is part of a family of proteins that are important for both O- and N-linked mannosylation in fungi and which represent a distinct subclass of glycosyltransferase enzymes. Here we use heterologous expression of CaMNT1 in the methylotrophic yeast Pichia pastoris to characterize the properties of the CaMnt1p enzyme as an example of this family of enzymes and to identify key amino acid residues required for coordination of the metal co-factor and for the retaining nucleophilic mechanism of the transferase reaction. We show that the enzyme can use both Mn(2+) and Zn(2+) as metal ion co-factors and that the reaction catalyzed is specific for alpha-methyl mannoside and alpha1,2-mannobiose acceptors. The N-terminal cytoplasmic tail, transmembrane domains, and stem regions were shown to be dispensable for activity, whereas truncations to the C-terminal catalytic domain destroyed activity without markedly affecting transcription of the truncated gene.
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Affiliation(s)
- L M Thomson
- Department of Molecular and Cell Biology, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom
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26
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Morioka K, Nojima H, Kurosaki E, Arisawa M, Kuraishi Y, Momose Y. Hypotensive action of Nangapiry, a Paraguayan natural medicine, in rodents. Phytomedicine 2000; 7:99-103. [PMID: 10839211 DOI: 10.1016/s0944-7113(00)80080-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Hypotensive action mechanism of a cation exchange resin adsorbate (IR-120A) separated from a Paraguayan Natural Medicine, Nangapiry, was investigated. Blood pressures of normal and pithed rats and contractions of isolated thoracic aorta and atria of mice were measured. The blood pressure on normal rats was reduced by an intravenous injection of IR-120A (5 mg/kg). The hypotensive effect on the pithed rat appeared more lasting than that on normal rats by IR-120A. The IR-120A (100 microg-3 mg/ml) concentration-dependently depressed prostaglandin (PG) F2alpha (10 microM)- or KCl (40 mM)-induced aortic contractions and electrically-evoked contraction of left atria, and at a lesser extent spontaneous beating rate of right atria. The 50% inhibitory concentrations (IC50) for the PGF2alpha- and KCl-induced aortic contractions were 713 and 828 microg/ml, respectively, and the IC50 values for the muscle contraction and the beating rate were 1.04 and >3 mg/ml, respectively. These results suggest that the hypotensive action of IR-120A are peripherally elicited by the dilatation of artery and the depression of heart contraction, but not the reduction of heart rate.
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MESH Headings
- Animals
- Aorta, Thoracic/physiology
- Blood Pressure/drug effects
- Chromatography, Ion Exchange
- Heart Atria
- In Vitro Techniques
- Ion Exchange Resins
- Male
- Medicine, Traditional
- Mice
- Mice, Inbred Strains
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Myocardial Contraction/drug effects
- Paraguay
- Plant Extracts/pharmacology
- Plant Leaves
- Plants, Medicinal
- Rats
- Rats, Sprague-Dawley
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Affiliation(s)
- K Morioka
- Laboratory of Herbal Garden, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan
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27
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Kurosaki F, Arisawa M, Shudo K, Okamoto T, Isogai Y. Nitric oxide form of a pyridylphenylurea is a potent inducer of shoot formation in plant tissue cultures. Anal Biochem 2000; 278:81-3. [PMID: 10640357 DOI: 10.1006/abio.1999.4419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- F Kurosaki
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, Toyama, 930-0194, Japan
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28
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Ikeda K, Takahashi M, Nishida M, Miyauchi M, Kizu H, Kameda Y, Arisawa M, Watson AA, Nash RJ, Fleet GW, Asano N. Homonojirimycin analogues and their glucosides from Lobelia sessilifolia and Adenophora spp. (Campanulaceae). Carbohydr Res 2000; 323:73-80. [PMID: 10782288 DOI: 10.1016/s0008-6215(99)00246-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
2,6-Dideoxy-7-O-(beta-D-glucopyranosyl) 2,6-imino-D-glycero-L-gulo- heptitol (7-O-beta-D-glucopyranosyl-alpha-homonojirimycin, 1) was isolated from the 50% methanol extract of the whole plant of Lobelia sessilifolia (Campanulaceae), which was found to potently inhibit rice alpha-glucosidase. Adenophorae radix, roots of Adenophora spp. (Campanulaceae), yielded new homonojirimycin derivatives, adenophorine (2), 1-deoxyadenophorine (3), 5-deoxyadenophorine (4), 1-C-(5-amino-5-deoxy-beta-D-galactopyranosyl)butane (beta-1-C-butyl-deoxygalactonojirimycin, 5), and the 1-O-beta-D-glucosides of 2 (6) and 4 (7), in addition to the recently discovered alpha-1-C-ethylfagomine (8) and the known 1-deoxymannojirimycin (9) and 2R,5R-bis(hydroxymethyl)-3R,4R- dihydroxypyrrolidine (DMDP, 10). Compound 4 is a potent inhibitor of coffee bean alpha-galactosidase (IC50 = 6.4 microM) and a reasonably good inhibitor of bovine liver beta-galactosidase (IC50 = 34 microM). Compound 5 is a very specific and potent inhibitor of coffee bean alpha-galactosidase (IC50 = 0.71 microM). The glucosides 1 and 7 were potent inhibitors of various alpha-glucosidases, with IC50 values ranging from 1 to 0.1 microM. Furthermore, 1 potently inhibited porcine kidney trehalase (IC50 = 0.013 microM) but failed to inhibit alpha-galactosidase, whereas 7 was a potent inhibitor of alpha-galactosidase (IC50 = 1.7 microM) without trehalase inhibitory activity.
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Affiliation(s)
- K Ikeda
- Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa, Japan
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29
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Matsumura T, Kasai M, Hayashi T, Arisawa M, Momose Y, Arai I, Amagaya S, Komatsu Y. a-glucosidase Inhibitors From Paraguayan Natural Medicine, Ñangapiry, The Leaves Of Eugenia Uniflora. Pharm Biol 2000; 38:302-307. [PMID: 21214481 DOI: 10.1076/1388-0209(200009)3841-aft302] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The water-soluble extract from a Paraguayan natural medicine, Nangapiry, the leaves of Eugenia uniflora L. (Myrtaceae), which has been used as an antidiabetic agent, was found to show inhibitory activities on the increase of plasma glucose level in the sucrose tolerance test (STT) conducted with mice. The portion adsorbed on a cation exchange resin was also found to inhibit a-glucosidases. From the active portion, two new active compounds named uniflorines A ( 1 ) and B ( 2 ) and known (+)-(3a, 4a, 5ß)-1-methylpiperidine-3, 4, 5-triol ( 3 ) were isolated. The structures of uniflorines A and B were determined as (-)-(1S, 2R, 6S, 7R, 8R, 8aR)-1,2,6,7,8-pentahydroxyindolizidine and (+)-(1S, 2R, 5R, 7R, 8S, 8aS)-1,2,5,7,8-pentahydroxyindolizidine by spectral means, respectively.
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30
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Abstract
One of the essential protein substrates of geranylgeranyl transferase type I in the budding yeast Saccharomyces cerevisiae is a rho-type GTPase, Rho1p, which is a regulatory subunit of 1, 3-beta-glucan synthase. Previous studies have indicated that modification of Rho1p is significantly reduced in a mutant of the beta subunit of geranylgeranyl transferase type I called cal1-1. Here we present genetic and biochemical evidence showing that modification of Rho1p is required for activity of 1,3-beta-glucan synthase. The 1,3-beta-glucan synthase activity of the cal1-1 membrane was significantly reduced compared with that of the wild-type membrane. The impaired activity was partly due to the reduced amount of Fks1p, a putative catalytic subunit of 1, 3-beta-glucan synthase, but also partly due to reduced affinity between unmodified Rho1p and Fks1p. Glutathione S-transferase (GST)-Rho1 proteins with or without the C-terminal motif required for the modification were purified and used to analyze the interaction. The modified form of GST-Rho1p was specifically able to restore the 1,3-beta-glucan synthase of the rho1-3 membrane. Gel overlay analysis indicated that an unmodified form of GST-Rho1p fails to interact with Fks1p. These results indicated that the geranylgeranylation of Rho1p is a prerequisite to the assembly and activation of 1,3-beta-glucan synthase in vitro. Increased cytoplasmic levels of divalent cations such as Ca(2+) restored both Rho1p modification and the 1,3-beta-glucan synthase activity of cal1-1, suggesting that cytoplasmic levels of the divalent cations affect geranylgeranyl transferase type I activity in vivo.
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Affiliation(s)
- S B Inoue
- Department of Mycology, Nippon Roche Research Center, 200 Kajiwara, Kamakura, Kanagawa 247-8530, Japan
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31
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Arai I, Amagaya S, Komatsu Y, Okada M, Hayashi T, Kasai M, Arisawa M, Momose Y. Improving effects of the extracts from Eugenia uniflora on hyperglycemia and hypertriglyceridemia in mice. J Ethnopharmacol 1999; 68:307-314. [PMID: 10624893 DOI: 10.1016/s0378-8741(99)00066-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
EtOH (70%) extracts from the leaves of Eugenia uniflora were separated into six fractions with different polarity and molecular size, i.e. NP-1-NP-6. In an oral glucose tolerance test, NP-1 and 4 inhibited the increase in plasma glucose level. However, in an intraperitoneal glucose tolerance test, such an inhibitory effect was not seen. Thus, the effects of NP-1 and 4 were apparently due to the inhibition of glucose absorption from the intestine. In a sucrose tolerance test, all fractions inhibited the increase in plasma glucose level. In an oral corn oil tolerance test, NP-3 and 4 showed an inhibitory effect on the increase in plasma triglycerides level. On the other hand, NP-3, 4, 5 and 6 inhibited maltase and sucrase activities and all fractions except for NP-1 showed an inhibitory effect on lipase activity dose-dependently. The inhibition of the increase in plasma glucose level by NP-3, 4, 5 and 6 in the oral sucrose tolerance test and the inhibition of the increase in plasma triglycerides by NP-3 and 4 in the oral corn oil tolerance test were apparently due to the inhibition of the decomposition of carbohydrates and fats in the intestine, respectively.
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Affiliation(s)
- I Arai
- Central Research Laboratories, Tsumura & Company, Ibaraki, Japan.
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32
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Yamada-Okabe T, Mio T, Ono N, Kashima Y, Matsui M, Arisawa M, Yamada-Okabe H. Roles of three histidine kinase genes in hyphal development and virulence of the pathogenic fungus Candida albicans. J Bacteriol 1999; 181:7243-7. [PMID: 10572127 PMCID: PMC103686 DOI: 10.1128/jb.181.23.7243-7247.1999] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pathogenic fungus Candida albicans harbors three histidine kinase genes called CaSLN1, CaNIK1, and CaHK1. The disruption of any one of these three genes impaired the hyphal formation and attenuated the virulence of C. albicans in a mouse systemic candidiasis model. The effects of the disruption on hyphal formation and virulence were most severe in the cahk1Delta null mutants. Although the double disruption of CaSLN1 and CaNIK1 was impossible, further deletion of CaSLN1 or CaNIK1 in the cahk1Delta null mutants partially restored the serum-induced hypha-forming ability and virulence. When incubated with radiolabelled ATP, the recombinant CaSln1 and CaNik1 proteins, which contained their own kinase and response regulator domains, were autophosphorylated, whereas CaHk1p was not. These results imply that in C. albicans, CaSLN1 and CaNIK1 function upstream of CaHK1 but are in distinct signal transmission pathways.
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Affiliation(s)
- T Yamada-Okabe
- Department of Hygiene, School of Medicine, Yokohama City University, 3-9, Fukuura, Kanazawa, Yokohama 236-0004, Japan
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33
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Hamada K, Terashima H, Arisawa M, Yabuki N, Kitada K. Amino acid residues in the omega-minus region participate in cellular localization of yeast glycosylphosphatidylinositol-attached proteins. J Bacteriol 1999; 181:3886-9. [PMID: 10383953 PMCID: PMC93875 DOI: 10.1128/jb.181.13.3886-3889.1999] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The final destination of glycosylphosphatidylinositol (GPI)-attached proteins in Saccharomyces cerevisiae is the plasma membrane or the cell wall. Two kinds of signals have been proposed for their cellular localization: (i) the specific amino acid residues V, I, or L at the site 4 or 5 amino acids upstream of the GPI attachment site (the omega site) and Y or N at the site 2 amino acids upstream of the omega site for cell wall localization and (ii) dibasic residues in the region upstream of the omega site (the omega-minus region) for plasma membrane localization. The relationships between these amino acid residues and efficiencies of cell wall incorporation were examined by constructing fusion reporter proteins from open reading frames encoding putative GPI-attached proteins. The levels of incorporation were high in the constructs containing the specific amino acid residues and quite low in those containing two basic amino acid residues in the omega-minus region. With constructs that contained neither specific residues nor two basic residues, levels of incorporation were moderate. These correlations clearly suggest that GPI-attached proteins have two different signals which act positively or negatively in cell wall incorporation for their cellular localization.
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Affiliation(s)
- K Hamada
- Department of Mycology, Nippon Roche Research Center, Kamakura, Kanagawa 247-8530, Japan
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34
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Yamazaki T, Kume H, Murase S, Yamashita E, Arisawa M. Epidemiology of visceral mycoses: analysis of data in annual of the pathological autopsy cases in Japan. J Clin Microbiol 1999; 37:1732-8. [PMID: 10325316 PMCID: PMC84937 DOI: 10.1128/jcm.37.6.1732-1738.1999] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The data on visceral mycoses that had been reported in the Annual of the Pathological Autopsy Cases in Japan from 1969 to 1994 by the Japanese Society of Pathology were analyzed epidemiologically. The frequency of visceral mycoses among the annual total number of pathological autopsy cases increased noticeably from 1.60% in 1969 to a peak of 4.66% in 1990. Among them, the incidences of candidiasis and aspergillosis increased the most. After 1990, however, the frequency of visceral mycoses decreased gradually. Until 1989, the predominant causative agent was Candida, followed in order by Aspergillus and Cryptococcus. Although the rate of candidiasis decreased by degrees from 1990, the rate of aspergillosis increased up to and then surpassed that of candidiasis in 1991. Leukemia was the major disease underlying the visceral mycoses, followed by solid cancers and other blood and hematopoietic system diseases. Severe mycotic infection has increased over the reported 25-year period, from 6.6% of the total visceral mycosis cases in 1969 to 71% in 1994. The reasons for this decrease of candidiasis combined with an increase of aspergillosis or of severe mycotic infection might be that (i) nonsevere (not disseminated) infections were excluded from the case totals, since they have become controllable by antifungal drugs such as fluconazole, but (ii) the available antifungal drugs were not efficacious against severe infections such as pulmonary aspergillosis, and (iii) the number of patients living longer in an immunocompromised state had increased because of developments in chemotherapy and progress in medical care.
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Affiliation(s)
- T Yamazaki
- Nippon Roche Research Center, Kamakura, Kanagawa 247-8530, University Hospital, School of Medicine, Kitasato University, Kanagawa 228-8550, Japan.
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Shiratori A, Shibata T, Arisawa M, Hanaoka F, Murakami Y, Eki T. Systematic identification, classification, and characterization of the open reading frames which encode novel helicase-related proteins in Saccharomyces cerevisiae by gene disruption and Northern analysis. Yeast 1999; 15:219-53. [PMID: 10077188 DOI: 10.1002/(sici)1097-0061(199902)15:3<219::aid-yea349>3.0.co;2-3] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Helicase-related proteins play important roles in various cellular processes incuding DNA replication, DNA repair, RNA processing and so on. It has been well known that the amino acid sequences of these proteins contain several conserved motifs, and that the open reading frames (ORFs) which encode helicase-related proteins make up several gene families. In this study, we have identified 134 ORFs that encode helicase-like proteins in the Saccharomyces genome, based on similarity with the ORFs of authentic helicase and helicase-related proteins. Multiple alignment of the ORF sequences resulted in the 134 ORFs being classified to 11 clusters. Seven out of 21 previously uncharacterized ORFs (YDL031w, YDL070w, YDL084w, YGL150c, YKL078w, YLR276c, and YMR128w) were identified by systematic gene disruption, to be essential for vegetative growth. Three (YDR332w, YGL064c, and YOL095c) out of the remaining 14 dispensable ORFs exhibited the slow-growth phenotype at 30 degrees C and 37 degrees C. Furthermore, the expression profiles of transcripts from 43 ORFs were examined under seven different growth conditions by Northern analysis and reverse transcription-polymerase chain reaction, indicating that all of the 43 tested ORFs were transcribed. Interestingly, we found that the level of transcript from 34 helicase-like genes was markedly increased by heat shock. This suggests that helicase-like genes may be involved in the biosynthesis of nucleic acids and proteins, and that the genes can be transcriptionally activated by heat shock to compensate for the repressed synthesis of mRNA and protein.
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Affiliation(s)
- A Shiratori
- Cellular Physiology Laboratory, Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKEN), Ibaraki, Japan
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36
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Mio T, Yamada-Okabe T, Arisawa M, Yamada-Okabe H. Saccharomyces cerevisiae GNA1, an essential gene encoding a novel acetyltransferase involved in UDP-N-acetylglucosamine synthesis. J Biol Chem 1999; 274:424-9. [PMID: 9867860 DOI: 10.1074/jbc.274.1.424] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Saccharomyces cerevisiae gene, YFL017C, for a putative acetyltransferase was characterized. Disruption of YFL017C was lethal, leading to a morphology similar to those caused by the depletion of AGM1 or UAP1, the genes encoding phospho-N-acetylglucosamine mutase and UDP-N-acetylglucosamine pyrophosphorylase, respectively. This implies the involvement of YFL017C in UDP-N-acetylglucosamine synthesis. The recombinant protein for YFL017C displayed phosphoglucosamine acetyltransferase activities in vitro and utilized glucosamine 6-phosphate as the substrate. When incubated with Agm1p and Uap1p, the Yfl017c protein produced UDP-N-acetylglucosamine from glucosamine 6-phosphate. These results indicate that YFL017C specifies glucosamine-6-phosphate acetyltransferase; therefore, the gene was designated GNA1 (glucosamine-6-phosphate acetyltransferase). In addition, whereas bacterial phosphoglucosamine acetyltransferase and UDP-N-acetylglucosamine pyrophosphorylase activities are intrinsic in a single polypeptide, they are encoded by distinct essential genes in yeast. When the sequence of ScGna1p was compared with those of other acetyltransferases, Ile97, Glu98, Val102, Gly112, Leu115, Ile116, Phe142, Tyr143, and Gly147 were found to be highly conserved. When alanine was substituted for these amino acids, the enzyme activity for the substituted Phe142 or Tyr143 enzymes was severely diminished. Although the activity of Y143A was too low to perform kinetics, F142A displayed a significantly increased Km value for acetyl-CoA, suggesting that the Phe142 and Tyr143 residues are essential for the catalysis.
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Affiliation(s)
- T Mio
- Department of Mycology, Nippon Roche Research Center, 200 Kajiwara, Kamakura, Kanagawa 247-8530, Japan
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37
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Matsumura Y, Uchida S, Kondo Y, Miyazaki H, Ko SB, Hayama A, Morimoto T, Liu W, Arisawa M, Sasaki S, Marumo F. Overt nephrogenic diabetes insipidus in mice lacking the CLC-K1 chloride channel. Nat Genet 1999; 21:95-8. [PMID: 9916798 DOI: 10.1038/5036] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CLC-K1 is a kidney-specific chloride channel that mediates transepithelial chloride transport in the thin ascending limb of Henle's loop (tAL) in the inner medulla. Transport of NaCl in the tAL is thought to be a component of urinary concentration in a passive model of the countercurrent multiplication system, but there has been no direct evidence that CLC-K1 is involved in urine concentration. To analyse the physiological function of CLC-K1 in vivo, we generated mice lacking CLC-K1 by targeted gene disruption. Clcnk1-/- mice were physically normal appearance, but produced approximately five times more urine than Clcnk1+/- and Clcnk1+/+ mice. After 24 hours of water deprivation, Clcnk1-/- mice were severely dehydrated and lethargic, with a decrease of approximately 27% in body weight. Intraperitoneal injection of the V2 agonist 1-deamino-8-D-arginine vasopressin (dDAVP) induced a threefold increase in urine osmolarity in Clcnk1+/- and Clcnk1+/+ mice, whereas only a minimal increase was seen in Clcnk1-/- mice, indicating nephrogenic diabetes insipidus. After in vitro perfusion of the tAL, the lumen-to-bath chloride gradient did not produce a diffusion potential in Clcnk1-/- mice in contrast to Clcnk1+/+ and Clcnk1+/- mice. These results establish that CLC-K1 has a role in urine concentration, and that the countercurrent system in the inner medulla is involved in the generation and maintenance of hypertonic medullary interstitium.
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Affiliation(s)
- Y Matsumura
- Second Department of Internal Medicine, Tokyo Medical and Dental University, School of Medicine, Japan
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38
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Yabe T, Yamada-Okabe T, Nakajima T, Sudoh M, Arisawa M, Yamada-Okabe H. Mutational analysis of chitin synthase 2 of Saccharomyces cerevisiae. Identification of additional amino acid residues involved in its catalytic activity. Eur J Biochem 1998; 258:941-7. [PMID: 9990311 DOI: 10.1046/j.1432-1327.1998.2580941.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Saccharomyces cerevisiae harbors three chitin synthases termed Chs1p, Chs2p and Chs3p. Previously, we demonstrated that con1, a region that is highly conserved among all chitin synthases, contains amino acids essential for the catalytic activity of the enzyme and that Asp562, Gln601, Arg604, and Trp605 found in con1 together with Asp441 were probable catalytic sites of the enzyme. Here we report that another region, con2, in the C-terminal half of Chs2p is also conserved exclusively in chitin synthases that resemble S. cerevisiae Chs1p and Chs2p. Alanine substitutions for the conserved amino acids in con2 identified five amino acids, Asn797, His799, Asp800, Trp803, and Thr805, the mutation of which severely diminished enzymatic activity and the enzyme's ability to rescue the yeast chs2 delta chs3 delta null mutant strain. Although the activities of some of the mutant enzymes were too low to measure enzyme kinetics, most of the alanine mutations in con2 affected the kcat values rather than the K(m) values. Whereas a conservative mutation of Asn797 restored the activity, those of His799, Asp800, Trp803, and Thr805 did not. A fine alignment of the amino acid sequences of con2 and Chs3p revealed that Asp800, Trp803 and Thr805 are completely conserved near the C-terminal ends of Chs3p and its homologs in other fungi. On the basis of these findings, we propose that Asp800, Trp803, and Thr805 in con2 are additional residues involved in catalysis, and hypothesise that Asp800 together with the previously identified Asp441 and Asp562 serve as polar residues necessary for the acid-based catalytic reaction of chitin synthase.
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Affiliation(s)
- T Yabe
- Department of Mycology, Nippon Roche Research Center, Kanagawa, Japan
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39
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Kurosaki F, Togashi K, Arisawa M. Role of reducing co-factor in cerulenin-insensitivity of 6-hydroxymellein synthase in carrot cell extract. Biochem Mol Biol Int 1998; 46:1219-25. [PMID: 9891855 DOI: 10.1080/15216549800204782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The activity of 6-hydroxymellein synthase, a multifunctional polyketide biosynthetic enzyme of carrot, was not inhibited by cerulenin in the presence of NADPH. However, cerulenin showed a marked inhibitory activity to the synthase if the reducing co-factor was omitted from the assay mixture. The synthase was also sensitive to the antibiotic even in the presence of NADPH when the acyl condensation site and the reducing domain at the reaction center of the enzyme were dissociated under the high ionic strength condition. In addition, the synthase activity was appreciably inhibited when NADH was employed instead of NADPH. These observations strongly suggest that a phosphate group attached to 2'-position of adenosyl moiety of NADPH molecule plays an important role in the apparent insensitivity of 6-hydroxymellein synthase toward cerulenin.
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Affiliation(s)
- F Kurosaki
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, Japan
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40
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Hamada K, Terashima H, Arisawa M, Kitada K. Amino acid sequence requirement for efficient incorporation of glycosylphosphatidylinositol-associated proteins into the cell wall of Saccharomyces cerevisiae. J Biol Chem 1998; 273:26946-53. [PMID: 9756943 DOI: 10.1074/jbc.273.41.26946] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During cell wall biogenesis in Saccharomyces cerevisiae, some glycosylphosphatidylinositol (GPI)-attached proteins are detached from GPI moieties and bound to beta-1,6-glucan of the cell wall. The amino acid sequence requirement for the incorporation of GPI-attached proteins into the cell wall was studied by using reporter fusion proteins. Only the short omega-minus region composed of five amino acids, which is located upstream of the omega site for GPI attachment, determined the cellular localization of the GPI-associated proteins. Within the omega-minus region, amino acid residues at the omega-4 or -5 and omega-2 sites were important for the cell wall incorporation. Yap3p, a well characterized GPI-anchored plasma membrane aspartic protease, was localized in the cell wall when the omega-minus region was mutated to sequences containing Val or Ile at the omega-4 or -5 site and Val or Tyr at the omega-2 site.
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Affiliation(s)
- K Hamada
- Department of Mycology, Nippon Roche Research Center, Kamakura, Kanagawa 247, Japan
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41
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Kurisaka M, Arisawa M, Mori T, Sakamoto T, Seike M, Mori K, Okada T, Wakiguchi H, Kurashige T. Combination chemotherapy (cisplatin, vinblastin) and low-dose irradiation in the treatment of pineal parenchymal cell tumors. Childs Nerv Syst 1998; 14:564-9. [PMID: 9840380 DOI: 10.1007/s003810050273] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Pineal parenchymal cell tumors (PPCTs) with or without metastasis into the lumbar region by way of the cerebrospinal fluid were treated successfully with combination chemotherapy using cisplatin, vinblastin, and bleomycin (PVB) or cisplatin and vinblastin (PV) and low-dose irradiation (25 approximately 30 Gy). Our series included a case of pineoblastoma, two cases of mixed pinocytoma/pineoblastoma, and a case of pineocytoma, compared to which the data held by the All Japan Brain Tumor Registry (AJBTR) included information on 47 cases pineocytoma and 20 of pineoblastoma. All our patients have survived, with scores of 90% or over on Karnofsky's performance scale, for 2-12 years of follow-up so far; however, the 5-year survival rates of the patients recorded by AJBTR were 83% for pineocytoma treated with radiation and 43% without radiation; and 42% for pineoblastoma treated with radiation and 50% without radiation. Incomplete or varied chemotherapeutic regimens used in different medical centers to treat PPCTs precluded an evaluation such as was made by AJBTR. Our results suggested that combination chemotherapy with low-dose back-up radiotherapy may be the treatment of choice for primary or recurrent disease with or without dissemination in PPCTs.
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Affiliation(s)
- M Kurisaka
- Department of Neurosurgery, Kochi Medical School, Nankoku City, Japan.
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42
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Yamada-Okabe T, Mio T, Matsui M, Kashima Y, Arisawa M, Yamada-Okabe H. Isolation and characterization of the Candida albicans gene for mRNA 5'-triphosphatase: association of mRNA 5'-triphosphatase and mRNA 5'-guanylyltransferase activities is essential for the function of mRNA 5'-capping enzyme in vivo. FEBS Lett 1998; 435:49-54. [PMID: 9755857 DOI: 10.1016/s0014-5793(98)01037-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The amino acid sequence of the Saccharomyces cerevisiae mRNA 5'-triphosphatase (TPase) diverges from those of higher eukaryotes. In order to confirm the sequence divergence of TPases in lower and higher eukaryotes, the Candida albicans gene for TPase was identified and characterized. This gene designated CaCET1 (C. albicans mRNA 5'-capping enzyme triphosphatase 1) has an open reading frame of 1.5 kb, which can encode a 59-kDa protein. Although the N-terminal one-fifth of S. cerevisiae TPase (ScCet1p) is missing in CaCet1p, CaCet1p shares significant sequence similarity with ScCet1p over the entire region of the protein; the recombinant CaCet1p, which was expressed as a fusion protein with glutathione S-transferase (GST), displayed TPase activity in vitro. CaCET1 rescued CET1-deficient S. cerevisiae cells when expressed under the control of the ADH1 promoter, whereas the human capping enzyme derivatives that are active for TPase activity but defective in mRNA 5'-guanylyltransferase (GTase) activity did not. Yeast two-hybrid analysis revealed that C. albicans Cet1p can bind to the S. cerevisiae GTase in addition to its own partner, the C. albicans GTase. In contrast, neither the full-length human capping enzyme nor its TPase domain interacted with the yeast GTase. These results indicate that the failure of the human TPase activity to complement an S. cerevisiae cet1delta null mutation is attributable, at least in part, to the inability of the human capping enzyme to associate with the yeast GTase, and that the physical association of GTase and TPase is essential for the function of the capping enzyme in vivo.
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43
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Mio T, Yabe T, Arisawa M, Yamada-Okabe H. The eukaryotic UDP-N-acetylglucosamine pyrophosphorylases. Gene cloning, protein expression, and catalytic mechanism. J Biol Chem 1998; 273:14392-7. [PMID: 9603950 DOI: 10.1074/jbc.273.23.14392] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A search of the yeast data base for a protein homologous to Escherichia coli UDP-N-acetylglucosamine pyrophosphorylase yielded UAP1 (UDP-N-acetylglucosamine pyrophosphorylase), the Saccharomyces cerevisiae gene for UDP-N-acetylglucosamine pyrophosphorylase. The Candida albicans and human homologs were also cloned by screening a C. albicans genomic library and a human testis cDNA library, respectively. Sequence analysis revealed that the human UAP1 cDNA was identical to previously reported AGX1. A null mutation of the S. cerevisiae UAP1 (ScUAP1) gene was lethal, and when expressed under the control of ScUAP1 promoter, both C. albicans and Homo sapiens UAP1 (CaUAP1 and HsUAP1) rescued the ScUAP1-deficient S. cerevisiae cells. All the recombinant ScUap1p, CaUap1p, and HsUap1p possessed UDP-N-acetylglucosamine pyrophosphorylase activities in vitro. The yeast Uap1p utilized N-acetylglucosamine-1-phosphate as the substrate, and together with Agm1p, it produced UDP-N-acetylglucosamine from N-acetylglucosamine-6-phosphate. These results demonstrate that the UAP1 genes indeed specify eukaryotic UDP-GlcNAc pyrophosphorylase and that phosphomutase reaction precedes uridyltransfer. Sequence comparison with other UDP-sugar pyrophosphorylases revealed that amino acid residues, Gly112, Gly114, Thr115, Arg116, Pro122, and Lys123 of ScUap1p are highly conserved in UDP-sugar pyrophosphorylases reported to date. Among these amino acids, alanine substitution for Gly112, Arg116, or Lys123 severely diminished the activity, suggesting that Gly112, Arg116, or Lys123 are possible catalytic residues of the enzyme.
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Affiliation(s)
- T Mio
- Department of Mycology, Nippon Roche Research Center, 200 Kajiwara, Kamakura, Kanagawa 247-8530, Japan
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44
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Abstract
Multiple drug resistance is becoming a major problem in the treatment of AIDS patients with oropharyngeal candidosis. Candida albicans strains isolated from candidosis patients who do not respond to fluconazole therapy often show azole drug resistance which usually correlates with the expression of C. albicans CDR1, CDR2 or BENr genes, encoding potential drug efflux pumps. The objective of this study was to develop a yeast secretory vesicle transport assay and use this system to study the pumping function of Cdr1 and Benr. The C. albicans CDR1 and BEN r genes were cloned separately into plasmid pVT101-U, to form plasmids pKY1011 and pKN5001 respectively. Plasmids pVT101-U, pKY1011 and pKN5001 were transformed into Saccharomyces cerevisiae SY1, a sec6-4 mutant with a temperature-sensitive mutation in the secretory pathway. SY1 cells transformed with pKY1011 or pKN5001, were more resistant to fluconazole (MICs in both cases 64 microg/ml) than SY1 cells (MIC 32 microg/ml). In addition, cells transformed with pKY1011 were more resistant to cycloheximide (MIC 16 microg/ml) than SY1 cells (MIC 2 microg/ml). Intact secretory vesicles were isolated from SY1 cells expressing Cdr1 and these vesicles accumulated fluconazole in a time dependent manner. These experiments demonstrated that S. cerevisiae secretory vesicles can be used to examine the mechanism of fluconazole transport by putative C. albicans membrane pumps.
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Affiliation(s)
- R D Cannon
- Department of Oral Sciences and Orthodontics, University of Otago, Dunedin, New Zealand
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45
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Aoki Y, Ishii N, Watanabe M, Yoshihara F, Arisawa M. [Rbf1 (RPG-box binding factor), a transcription factor involved in yeast-hyphal transition of Candida albicans]. Nihon Ishinkin Gakkai Zasshi 1998; 39:67-71. [PMID: 9580030 DOI: 10.3314/jjmm.39.67] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The major fungal pathogen for fungal diseases which have become a major medical problem in the last few years is Candida albicans, which can grow both in yeast and hyphae forms. This ability of C. albicans is thought to contribute to its colonization and dissemination within host tissues. In a recent few years, accompanying the introduction of molecular biological tools into C. albicans organism, several factors involved in the signal transduction pathway for yeast-hyphal transition have been identified. One MAP kinase pathway in C. albicans, similar to that leading to STE12 activation in Saccharomyces cerevisiae, has been reported. C. albicans strains mutant in these genes show retarded filamentous growth on a solid media but no impairment of filamentous growth in mice. These results suggest two scenarios that a kinase signaling cascade plays a part in stimulating the morphological transition in C. albicans, and that there would be another signaling pathway effective in animals. In this latter true hyphal pathway, although some candidate proteins, such as Efg1 (transcription factor), Int1 (integrin-like membrane protein), or Phr1 (pH-regulated membrane protein), have been identified, it is still too early to say that we understand the whole picture of that cascade. We have cloned a C. albicans gene encoding a novel DNA binding protein, Rbf1, that predominantly localizes in the nucleus, and shows transcriptional activation capability. Disruption of the functional RBF1 genes of C. albicans induced the filamentous growth on all solid and liquid media tested, suggesting that Rbf1 might be another candidate for the true hyphal pathway. Relationships with other factors described above, and the target (regulated) genes of Rbf1 is under investigation.
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Affiliation(s)
- Y Aoki
- Mycology Department, Nippon Roche Research Center, 200, Kajiwara, Kamakura, Kanagawa 247-0063, Japan
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46
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Hamada K, Fukuchi S, Arisawa M, Baba M, Kitada K. Screening for glycosylphosphatidylinositol (GPI)-dependent cell wall proteins in Saccharomyces cerevisiae. Mol Gen Genet 1998; 258:53-9. [PMID: 9613572 DOI: 10.1007/s004380050706] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Open reading frames in the genome of Saccharomyces cerevisiae were screened for potential glycosylphosphatidylinositol (GPI)-attached proteins. The identification of putative GPI-attached proteins was based on three criteria: the presence of a GPI-attachment signal sequence, a signal sequence for secretion and a serine- or threonine-rich sequence. In all, 53 ORFs met these three criteria and 38 were further analyzed as follows. The sequence encoding the 40 C-terminal amino acids of each was fused with the structural gene for a reporter protein consisting of a secretion signal, alpha-galactosidase and a hemagglutinin (HA) epitope, and examined for the ability to become incorporated into the cell wall. On this basis, 14 of fusion proteins were classified as GPI-dependent cell wall proteins because cells expressing these fusion proteins: (i) had high levels of alpha-galactosidase activity on their surface; (ii) released significant amounts of the fusion proteins from the membrane on treatment with phosphatidylinositol-specific phospholipase C (PI-PLC); and (iii) released fusion proteins from the cell wall following treatment with laminarinase. Of the 14 identified putative GPI-dependent cell wall proteins, 12 had novel ORFs adjacent to their GPI-attachment signal sequence. Amino acid sequence alignment of the C-terminal sequences of the 12 ORFs, together with those of known cell wall proteins, reveals some sequence similarities among them.
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Affiliation(s)
- K Hamada
- Department of Mycology, Nippon Roche Research Center, Kanagawa, Japan
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47
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Abstract
The human mRNA 5'-capping enzyme cDNA was identified. Three highly related cDNAs, HCE1 (human mRNAcappingenzyme1), HCE1A and HCE1B , were isolated from a HeLa cDNA library. The HCE1 cDNA has the longest ORF, which can encode a 69 kDa protein. A short region of 69 bp in the 3'-half of the HCE1 ORF was missing in HCE1A and HCE1B , and, additionally, HCE1B has an early translation termination signal, which suggests that the latter two cDNAs represent alternatively spliced product. When expressed in Escherichia coli as a fusion protein with glutathione S -transferase, Hce1p displayed both mRNA 5'-triphosphatase (TPase) and mRNA 5'-guanylyltransferase (GTase) activities, and it formed a cap structure at the 5'-triphosphate end of RNA, demonstrating that it indeed specifies an active mRNA 5'-capping enzyme. The recombinant proteins derived from HCE1A and HCE1B possessed only TPase activity. When expressed from ADH1 promoter, HCE1 but not HCE1A and HCE1B complemented Saccharomyces cerevisiae CEG1 and CET1 , the genes for GTase and TPase, respectively. These results demonstrate that the N-terminal part of Hce1p is responsible for TPase activity and the C-terminal part is essential for GTase activity. In addition, the human TPase domain cannot functionally substitute for the yeast enzyme in vivo.
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Affiliation(s)
- T Yamada-Okabe
- Department of Hygiene, School of Medicine, Yokohama City University, 3-9, Fukuura, Kanazawa, Yokohama 236, Japan
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48
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Abstract
The Saccharomyces cerevisiae RHO1 gene encodes a low-molecular-weight GTPase. One of its recently identified functions is the regulation of beta-1,3-glucan synthase, which synthesizes the main component of the fungal cell wall (J. Drgonova et al., Science 272:277-279, 1996; T. Mazur and W. Baginsky, J. Biol. Chem. 271:14604-14609, 1996; and H. Qadota et al., Science 272:279-281, 1996). From the opportunistic pathogenic fungus Candida albicans, we cloned the RHO1 gene by the PCR and cross-hybridization methods. Sequence analysis revealed that the Candida RHO1 gene has a 597-nucleotide region which encodes a putative 22.0-kDa peptide. The deduced amino acid sequence predicts that Candida albicans Rho1p is 82.9% identical to Saccharomyces Rho1p and contains all the domains conserved among Rho-type GTPases from other organisms. The Candida albicans RHO1 gene could rescue a S. cerevisiae strain containing a rho1 deletion. Furthermore, recombinant Candida albicans Rho1p could reactivate the beta-1,3-glucan synthesis activities of both C. albicans and S. cerevisiae membranes in which endogenous Rho1p had been depleted by Tergitol NP-40-NaCl treatment. Candida albicans Rho1p was copurified with the beta-1,3-glucan synthase putative catalytic subunit, Candida albicans Gsc1p, by product entrapment. Candida albicans Rho1p was shown to interact directly with Candida albicans Gsc1p in a ligand overlay assay and a cross-linking study. These results indicate that Candida albicans Rho1p acts in the same manner as Saccharomyces cerevisiae Rho1p to regulate beta-1,3-glucan synthesis.
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Affiliation(s)
- O Kondoh
- Department of Mycology, Nippon Roche Research Center, Kamakura, Kanagawa, Japan.
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49
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Abstract
A method is described for selecting monoclonal antibodies (mAb) against DNA-binding protein. The protocol involves a non-radioactive solid-phase DNA binding assay using a 96-well plate. Because the solid-phase assay is highly specific and sensitive, partially purified antigen is sufficient for the immunization, and mAb screening can be performed with crude cell extract as the antigen. MAbs obtained by this method could supershift the DNA-protein complex in the electromobility shift assay, and were sufficient for immunoscreening of a cDNA expression library.
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Affiliation(s)
- N Ishii
- Department of Mycology, Nippon Roche Research Center (NRRC), Kajiwara 200, Kamakura 247, Japan.
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50
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Mio T, Adachi-Shimizu M, Tachibana Y, Tabuchi H, Inoue SB, Yabe T, Yamada-Okabe T, Arisawa M, Watanabe T, Yamada-Okabe H. Cloning of the Candida albicans homolog of Saccharomyces cerevisiae GSC1/FKS1 and its involvement in beta-1,3-glucan synthesis. J Bacteriol 1997; 179:4096-105. [PMID: 9209021 PMCID: PMC179227 DOI: 10.1128/jb.179.13.4096-4105.1997] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Saccharomyces cerevisiae GSC1 (also called FKS1) and GSC2 (also called FKS2) have been identified as the genes for putative catalytic subunits of beta-1,3-glucan synthase. We have cloned three Candida albicans genes, GSC1, GSL1, and GSL2, that have significant sequence homologies with S. cerevisiae GSC1/FKS1, GSC2/FKS2, and the recently identified FKSA of Aspergillus nidulans at both nucleotide and amino acid levels. Like S. cerevisiae Gsc/Fks proteins, none of the predicted products of C. albicans GSC1, GSL1, or GSL2 displayed obvious signal sequences at their N-terminal ends, but each product possessed 10 to 16 potential transmembrane helices with a relatively long cytoplasmic domain in the middle of the protein. Northern blotting demonstrated that C. albicans GSC1 and GSL1 but not GSL2 mRNAs were expressed in the growing yeast-phase cells. Three copies of GSC1 were found in the diploid genome of C. albicans CAI4. Although we could not establish the null mutation of C. albicans GSC1, disruption of two of the three GSC1 alleles decreased both GSC1 mRNA and cell wall beta-glucan levels by about 50%. The purified C. albicans beta-1,3-glucan synthase was a 210-kDa protein as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and all sequences determined with peptides obtained by lysyl endopeptidase digestion of the 210-kDa protein were found in the deduced amino acid sequence of C. albicans Gsc1p. Furthermore, the monoclonal antibody raised against the purified beta-1,3-glucan synthase specifically reacted with the 210-kDa protein and could immunoprecipitate beta-1,3-glucan synthase activity. These results demonstrate that C. albicans GSC1 is the gene for a subunit of beta-1,3-glucan synthase.
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Affiliation(s)
- T Mio
- Department of Mycology, Nippon Roche Research Center, Kamakura, Kanagawa, Japan.
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