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Yamazaki A, Tanaka Y, Watanabe K, Sato M, Kawazu SI, Kita K, Inoue N, van Rensburg HDJ, N'Da DD, Suganuma K. Prophylactic activity of orally administered dry-heat-sterilized Acremonium egyptiacum against Trypanosoma congolense-induced animal African trypanosomosis. Acta Trop 2024; 254:107185. [PMID: 38494059 DOI: 10.1016/j.actatropica.2024.107185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 02/08/2024] [Accepted: 03/10/2024] [Indexed: 03/19/2024]
Abstract
Animal African trypanosomosis (AAT) is an important global disease of livestock that causes economic losses of up to 4.5 billion US dollars per year. Thus, eliminating AAT in endemic countries will improve agricultural productivity and economic growth. To prevent AAT, vector control and the development of prophylactic drugs are crucial. Ascofuranone (AF) is a bioactive fungal compound with proven in vitro trypanocidal potency and in vivo treatment efficacy. However, the complex stereoselective synthesis of AF has prevented its cost-effective industrial production. Recently, a genetically modified strain of Acremonium egyptiacum fungus that produces a high yield of AF was developed. Therefore, we hypothesized that the oral administration of the AF-producing fungus itself may be effective against AAT. Hence, this study aimed to evaluate the prophylactic activity of orally administered dry-heat-sterilized A. egyptiacum against Trypanosoma congolense IL3000 infection using a mouse model. The survival rate was significantly prolonged (p = 0.009), and parasitemia was suppressed in all AF-fungus-treated groups (Group 1-9) compared with that in the untreated control group (Group 10). Hence, the trypanocidal activity of AF was retained after dry-heat-sterilization of the AF-producing fungus and that its oral administration effectively prevented AAT. Since AAT is endemic to rural areas with underdeveloped veterinary infrastructure, dry-heat-sterilized A. egyptiacum would be the most cost-effective potential treatment for AAT.
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Affiliation(s)
- Ai Yamazaki
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido, 080-8555, Japan
| | - Yusuke Tanaka
- Department of Functional Anatomy and Neuroscience, Asahikawa Medical University, Asahikawa, Hokkaido, 078-8510, Japan
| | - Kenichi Watanabe
- Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan; Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Mayu Sato
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Shin-Ichiro Kawazu
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido, 080-8555, Japan
| | - Kiyoshi Kita
- School of Tropical Medicine and Global Health, Nagasaki University, Sakamoto, Nagasaki 852-8523, Japan
| | - Noboru Inoue
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido, 080-8555, Japan
| | - Helena D Janse van Rensburg
- Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom 2520, South Africa
| | - David D N'Da
- Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom 2520, South Africa
| | - Keisuke Suganuma
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido, 080-8555, Japan; Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan.
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Gao H, Zhou L, Zhang P, Wang Y, Qian X, Liu Y, Wu G. Filamentous Fungi-Derived Orsellinic Acid-Sesquiterpene Meroterpenoids: Fungal Sources, Chemical Structures, Bioactivities, and Biosynthesis. PLANTA MEDICA 2023; 89:1110-1124. [PMID: 37225133 DOI: 10.1055/a-2099-4932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Fungi-derived polyketide-terpenoid hybrids are important meroterpenoid natural products that possess diverse structure scaffolds with a broad spectrum of bioactivities. Herein, we focus on an ever-increasing group of meroterpenoids, orsellinic acid-sesquiterpene hybrids comprised of biosynthetic start unit orsellinic acid coupling to a farnesyl group or/and its modified cyclic products. The review entails the search of China National Knowledge Infrastructure (CNKI), Web of Science, Science Direct, Google Scholar, and PubMed databases up to June 2022. The key terms include "orsellinic acid", "sesquiterpene", "ascochlorin", "ascofuranone", and "Ascochyta viciae", which are combined with the structures of "ascochlorin" and "ascofuranone" drawn by the Reaxys and Scifinder databases. In our search, these orsellinic acid-sesquiterpene hybrids are mainly produced by filamentous fungi. Ascochlorin was the first compound reported in 1968 and isolated from filamentous fungus Ascochyta viciae (synonym: Acremonium egyptiacum; Acremonium sclerotigenum); to date, 71 molecules are discovered from various filamentous fungi inhabiting in a variety of ecological niches. As typical representatives of the hybrid molecules, the biosynthetic pathway of ascofuranone and ascochlorin are discussed. The group of meroterpenoid hybrids exhibits a broad arrange of bioactivities, as highlighted by targeting hDHODH (human dihydroorotate dehydrogenase) inhibition, antitrypanosomal, and antimicrobial activities. This review summarizes the findings related to the structures, fungal sources, bioactivities, and their biosynthesis from 1968 to June 2022.
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Affiliation(s)
- Hua Gao
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, People's Republic of China
| | - Luning Zhou
- Key Laboratory of Marine Drugs, Chinese Ministry of Education; School of Medicine and Pharmacy, Ocean University of China, Qingdao, Shandong, People's Republic of China
| | - Peng Zhang
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, United States
| | - Ying Wang
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, People's Republic of China
| | - Xuan Qian
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, People's Republic of China
| | - Yujia Liu
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, People's Republic of China
| | - Guangwei Wu
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, People's Republic of China
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Yamazaki A, Suganuma K, Tanaka Y, Watanabe K, Kawazu SI, Kita K, Inoue N. Efficacy of oral administration of ascofuranone with and without glycerol against Trypanosoma congolense. Exp Parasitol 2023; 252:108588. [PMID: 37499895 DOI: 10.1016/j.exppara.2023.108588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/28/2023] [Accepted: 07/23/2023] [Indexed: 07/29/2023]
Abstract
In many developing countries, trypanosomosis in animals results in the reduction of livestock productivity. Since trypanosomosis is endemic to rural areas where medical and veterinary infrastructure is underdeveloped, development of affordable and easy-to-maintain drugs for treatment and prophylaxis against trypanosomosis is necessary. To this end, in this study, we evaluated the efficacy of oral administration of ascofuranone (AF), with and without glycerol (GOL), against trypanosomosis, using a mouse model. We used T. congolense IL3000, the most virulent animal-infecting trypanosome, and BALB/c mice in this study. Eight mice were assigned to either of Groups 1-7: non-infected, untreated, AF 10, 20, 30, 50, and 100 mg/kg with or without GOL, respectively. In the experiment with AF administered with GOL, survival rates were 0% in Group 2 (untreated) and Group 3 (AF 10 mg/kg), 37.5% in Group 4 (AF 20 mg/kg) and Group 5 (AF 30 mg/kg), 50% in Group 6 (AF 50 mg/kg), and 100% in Group 7 (AF 100 mg/kg). In groups in which AF was administered without GOL, survival rates were 0% in Group 2 (untreated), Group 3 (AF 10 mg/kg), Group 4 (AF 20 mg/kg), Group 5 (AF 30 mg/kg), and Group 6 (AF 50 mg/kg), and 12.5% in Group 7 (AF 100 mg/kg), with one mouse surviving till the end of the observation period. The results of the analysis showed that survival rates were significantly higher in all groups (Groups 3-7) than in the untreated group (Group 2) (p < 0.05). Furthermore, a comparison of groups with or without GOL at the same AF concentration revealed that the survival rate was significantly higher in the group treated with GOL. These results suggest that the treatment efficacy of AF against animal trypanosomosis caused by T. congolense is greater when co-administered with GOL, and that oral administration of AF could be a new therapeutic strategy for animal African trypanosomosis.
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Affiliation(s)
- Ai Yamazaki
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido, 080-8555, Japan.
| | - Keisuke Suganuma
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido, 080-8555, Japan; Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido, 080-8555, Japan.
| | - Yusuke Tanaka
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido, 080-8555, Japan.
| | - Kenichi Watanabe
- Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido, 080-8555, Japan; Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido, 080-8555, Japan.
| | - Shin-Ichiro Kawazu
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido, 080-8555, Japan.
| | - Kiyoshi Kita
- School of Tropical Medicine and Global Health, Nagasaki University, Sakamoto, Nagasaki, 852-8523, Japan; Department of Host-Defense Biochemistry, Institute of Tropical Medicine, Nagasaki University, Nagasaki, 852-8523, Japan.
| | - Noboru Inoue
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido, 080-8555, Japan.
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Jiang N, Li SZ, Zhang YWQ, Habib MR, Xiong T, Xu S, Dong H, Zhao QP. The identification of alternative oxidase in intermediate host snails of Schistosoma and its potential role in protecting Oncomelania hupensis against niclosamide-induced stress. Parasit Vectors 2022; 15:97. [PMID: 35313980 PMCID: PMC8935807 DOI: 10.1186/s13071-022-05227-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 03/03/2022] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Snail intermediate hosts are mandatory for the transmission of schistosomiasis, which has to date infected more than 200 million people worldwide. Our previous studies showed that niclosamide treatment caused the inhibition of aerobic respiration and oxidative phosphorylation, and the disruption of energy supply, in one of the intermediate hosts of schistosomiasis, Oncomelania hupensis, which eventually led to the death of the snails. Meanwhile, the terminal oxidase in the mitochondrial respiratory chain, alternative oxidase (AOX), was significantly up-regulated, which was thought to counterbalance the oxidative stress and maintain metabolic homeostasis in the snails. The aims of the present study are to identify the AOXs in several species of snails and investigate the potential activation of O. hupensis AOX (OhAOX) under niclosamide-induced stress, leading to enhanced survival of the snail when exposed to this molluscicide. METHODS The complete complementary DNA was amplified from the AOXs of O. hupensis and three species of Biomphalaria; the sequence characteristics were analysed and the phylogenetics investigated. The dynamic expression and localisation of the AOX gene and protein in O. hupensis under niclosamide-induced stress were examined. In addition, the expression pattern of genes in the mitochondrial respiratory complex was determined and the production of reactive oxygen species (ROS) calculated. Finally, the molluscicidal effect of niclosamide was compared between snails with and without inhibition of AOX activity. RESULTS AOXs containing the invertebrate AOX-specific motif NP-[YF]-XPG-[KQE] were identified from four species of snail, which phylogenetically clustered together into Gastropoda AOXs and further into Mollusca AOXs. After niclosamide treatment, the levels of OhAOX messenger RNA (mRNA) and OhAOX protein in the whole snail were 14.8 and 2.6 times those in untreated snails, respectively, but varied widely among tissues. Meanwhile, the level of cytochrome C reductase mRNA showed a significant decrease in the whole snail, and ROS production showed a significant decrease in the liver plus gonad (liver-gonad) of the snails. At 24 h post-treatment, the mortality of snails treated with 0.06-0.1 mg/L niclosamide and AOX inhibitor was 56.31-76.12% higher than that of snails treated with 0.1 mg/L niclosamide alone. CONCLUSIONS AOX was found in all the snail intermediate hosts of Schistosoma examined here. AOX was significantly activated in O. hupensis under niclosamide-induced stress, which led to a reduction in oxidative stress in the snail. The inhibition of AOX activity in snails can dramatically enhance the molluscicidal effect of niclosamide. A potential target for the development of an environmentally safe snail control method, which acts by inhibiting the activity of AOX, was identified in this study.
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Affiliation(s)
- Ni Jiang
- Department of Parasitology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei China
- Joint Inspection Center of Precision Medicine, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi China
| | - Shi-Zhu Li
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, National Center for Tropical Diseases Research, WHO Collaborating Center for Tropical Diseases, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, China
| | - Yang-Wen-Qing Zhang
- Department of Parasitology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei China
| | - Mohamed R. Habib
- Medical Malacology Department, Theodor Bilharz Research Institute, Giza, Egypt
| | - Tao Xiong
- Department of Microbiology, School of Medical Sciences, Hunan University of Chinese Medicine, Changsha, Hunan China
| | - Sha Xu
- Department of Parasitology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei China
| | - Huifen Dong
- Department of Parasitology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei China
| | - Qin-Ping Zhao
- Department of Parasitology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei China
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Barsottini MRO, Copsey A, Young L, Baroni RM, Cordeiro AT, Pereira GAG, Moore AL. Biochemical characterization and inhibition of the alternative oxidase enzyme from the fungal phytopathogen Moniliophthora perniciosa. Commun Biol 2020; 3:263. [PMID: 32451394 PMCID: PMC7248098 DOI: 10.1038/s42003-020-0981-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 04/30/2020] [Indexed: 01/27/2023] Open
Abstract
Moniliophthora perniciosa is a fungal pathogen and causal agent of the witches' broom disease of cocoa, a threat to the chocolate industry and to the economic and social security in cocoa-planting countries. The membrane-bound enzyme alternative oxidase (MpAOX) is crucial for pathogen survival; however a lack of information on the biochemical properties of MpAOX hinders the development of novel fungicides. In this study, we purified and characterised recombinant MpAOX in dose-response assays with activators and inhibitors, followed by a kinetic characterization both in an aqueous environment and in physiologically-relevant proteoliposomes. We present structure-activity relationships of AOX inhibitors such as colletochlorin B and analogues which, aided by an MpAOX structural model, indicates key residues for protein-inhibitor interaction. We also discuss the importance of the correct hydrophobic environment for MpAOX enzymatic activity. We envisage that such results will guide the future development of AOX-targeting antifungal agents against M. perniciosa, an important outcome for the chocolate industry.
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Affiliation(s)
- Mario R O Barsottini
- Genomics and bioEnergy Laboratory, Institute of Biology, University of Campinas, Campinas, Brazil.,Biochemistry & Biomedicine, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
| | - Alice Copsey
- Biochemistry & Biomedicine, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
| | - Luke Young
- Biochemistry & Biomedicine, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
| | - Renata M Baroni
- Genomics and bioEnergy Laboratory, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Artur T Cordeiro
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Gonçalo A G Pereira
- Genomics and bioEnergy Laboratory, Institute of Biology, University of Campinas, Campinas, Brazil.
| | - Anthony L Moore
- Biochemistry & Biomedicine, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK.
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Ebiloma GU, Balogun EO, Cueto-Díaz EJ, de Koning HP, Dardonville C. Alternative oxidase inhibitors: Mitochondrion-targeting as a strategy for new drugs against pathogenic parasites and fungi. Med Res Rev 2019; 39:1553-1602. [PMID: 30693533 DOI: 10.1002/med.21560] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/07/2018] [Accepted: 12/08/2018] [Indexed: 12/11/2022]
Abstract
The alternative oxidase (AOX) is a ubiquitous terminal oxidase of plants and many fungi, catalyzing the four-electron reduction of oxygen to water alongside the cytochrome-based electron transfer chain. Unlike the classical electron transfer chain, however, the activity of AOX does not generate adenosine triphosphate but has functions such as thermogenesis and stress response. As it lacks a mammalian counterpart, it has been investigated intensely in pathogenic fungi. However, it is in African trypanosomes, which lack cytochrome-based respiration in their infective stages, that trypanosome alternative oxidase (TAO) plays the central and essential role in their energy metabolism. TAO was validated as a drug target decades ago and among the first inhibitors to be identified was salicylhydroxamic acid (SHAM), which produced the expected trypanocidal effects, especially when potentiated by coadministration with glycerol to inhibit anaerobic energy metabolism as well. However, the efficacy of this combination was too low to be of practical clinical use. The antibiotic ascofuranone (AF) proved a much stronger TAO inhibitor and was able to cure Trypanosoma vivax infections in mice without glycerol and at much lower doses, providing an important proof of concept milestone. Systematic efforts to improve the SHAM and AF scaffolds, aided with the elucidation of the TAO crystal structure, provided detailed structure-activity relationship information and reinvigorated the drug discovery effort. Recently, the coupling of mitochondrion-targeting lipophilic cations to TAO inhibitors has dramatically improved drug targeting and trypanocidal activity while retaining target protein potency. These developments appear to have finally signposted the way to preclinical development of TAO inhibitors.
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Affiliation(s)
- Godwin U Ebiloma
- Department of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto, Japan.,Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Emmanuel O Balogun
- Department of Biochemistry, Ahmadu Bello University, Zaria, Nigeria.,Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | | | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Ebiloma GU, Ayuga TD, Balogun EO, Gil LA, Donachie A, Kaiser M, Herraiz T, Inaoka DK, Shiba T, Harada S, Kita K, de Koning HP, Dardonville C. Inhibition of trypanosome alternative oxidase without its N-terminal mitochondrial targeting signal (ΔMTS-TAO) by cationic and non-cationic 4-hydroxybenzoate and 4-alkoxybenzaldehyde derivatives active against T. brucei and T. congolense. Eur J Med Chem 2018; 150:385-402. [PMID: 29544150 DOI: 10.1016/j.ejmech.2018.02.075] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/22/2018] [Accepted: 02/23/2018] [Indexed: 11/28/2022]
Abstract
African trypanosomiasis is a neglected parasitic disease that is still of great public health relevance, and a severe impediment to agriculture in endemic areas. The pathogens possess certain unique metabolic features that can be exploited for the development of new drugs. Notably, they rely on an essential, mitochondrially-localized enzyme, Trypanosome Alternative Oxidase (TAO) for their energy metabolism, which is absent in the mammalian hosts and therefore an attractive target for the design of safe drugs. In this study, we cloned, expressed and purified the physiologically relevant form of TAO, which lacks the N-terminal 25 amino acid mitochondrial targeting sequence (ΔMTS-TAO). A new class of 32 cationic and non-cationic 4-hydroxybenzoate and 4-alkoxybenzaldehyde inhibitors was designed and synthesized, enabling the first structure-activity relationship studies on ΔMTS-TAO. Remarkably, we obtained compounds with enzyme inhibition values (IC50) as low as 2 nM, which were efficacious against wild type and multidrug-resistant strains of T. brucei and T. congolense. The inhibitors 13, 15, 16, 19, and 30, designed with a mitochondrion-targeting lipophilic cation tail, displayed trypanocidal potencies comparable to the reference drugs pentamidine and diminazene, and showed no cross-resistance with the critical diamidine and melaminophenyl arsenical classes of trypanocides. The cationic inhibitors 15, 16, 19, 20, and 30 were also much more selective (900 - 344,000) over human cells than the non-targeted neutral derivatives (selectivity >8-fold). A preliminary in vivo study showed that modest doses of 15 and 16 reduced parasitaemia of mice infected with T. b. rhodesiense (STIB900). These compounds represent a promising new class of potent and selective hits against African trypanosomes.
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Affiliation(s)
- Godwin U Ebiloma
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; Department of Biochemistry, Kogi State University, Anyigba, Nigeria
| | - Teresa Díaz Ayuga
- Instituto de Química Médica, IQM-CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
| | - Emmanuel O Balogun
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Japan; Department of Biochemistry, Ahmadu Bello University, Zaria 2222, Nigeria
| | - Lucía Abad Gil
- Instituto de Química Médica, IQM-CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
| | - Anne Donachie
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Marcel Kaiser
- Swiss Tropical and Public Health Institute, Socinstrasse, 57, CH-4002 Basel, Switzerland
| | - Tomás Herraiz
- Instituto de Ciencia y Tecnología de Alimentos y Nutrición, ICTAN-CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
| | - Daniel K Inaoka
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Japan; School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, 852-8523, Japan
| | - Tomoo Shiba
- Department of Applied Biology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Shigeharu Harada
- Department of Applied Biology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Kiyoshi Kita
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Japan; School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, 852-8523, Japan
| | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
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Abstract
SUMMARYNew drugs against Trypanosoma brucei, the causative agent of Human African Trypanosomiasis, are urgently needed to replace the highly toxic and largely ineffective therapies currently used. The trypanosome alternative oxidase (TAO) is an essential and unique mitochondrial protein in these parasites and is absent from mammalian mitochondria, making it an attractive drug target. The structure and function of the protein are now well characterized, with several inhibitors reported in the literature, which show potential as clinical drug candidates. In this review, we provide an update on the functional activity and structural aspects of TAO. We then discuss TAO inhibitors reported to date, problems encountered with in vivo testing of these compounds, and discuss the future of TAO as a therapeutic target.
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Heterologous expression of the Crassostrea gigas (Pacific oyster) alternative oxidase in the yeast Saccharomyces cerevisiae. J Bioenerg Biomembr 2016; 48:509-520. [PMID: 27816999 DOI: 10.1007/s10863-016-9685-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 10/25/2016] [Indexed: 12/17/2022]
Abstract
Alternative oxidase (AOX) is a terminal oxidase within the inner mitochondrial membrane (IMM) present in many organisms where it functions in the electron transport system (ETS). AOX directly accepts electrons from ubiquinol and is therefore capable of bypassing ETS Complexes III and IV. The human genome does not contain a gene coding for AOX, so AOX expression has been suggested as a gene therapy for a range of human mitochondrial diseases caused by genetic mutations that render Complex III and/or IV dysfunctional. An effective means of screening mutations amenable to AOX treatment remains to be devised. We have generated such a tool by heterologously expressing AOX from the Pacific oyster (Crassostrea gigas) in the yeast Saccharomyces cerevisiae under the control of a galactose promoter. Our results show that this animal AOX is monomeric and is correctly targeted to yeast mitochondria. Moreover, when expressed in yeast, Pacific oyster AOX is a functional quinol oxidase, conferring cyanide-resistant growth and myxothiazol-resistant oxygen consumption to yeast cells and isolated mitochondria. This system represents a high-throughput screening tool for determining which Complex III and IV genetic mutations in yeast will be amenable to AOX gene therapy. As many human genes are orthologous to those found in yeast, our invention represents an efficient and cost-effective way to evaluate viable research avenues. In addition, this system provides the opportunity to learn more about the localization, structure, and regulation of AOXs from animals that are not easily reared or manipulated in the lab.
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10
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Torrentino-Madamet M, Almeras L, Travaillé C, Sinou V, Pophillat M, Belghazi M, Fourquet P, Jammes Y, Parzy D. Proteomic analysis revealed alterations of the Plasmodium falciparum metabolism following salicylhydroxamic acid exposure. Res Rep Trop Med 2011; 2:109-119. [PMID: 30881184 DOI: 10.2147/rrtm.s23127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVES Although human respiratory metabolism is characterized by the mitochondrial electron transport chain, some organisms present a "branched respiratory chain." This branched pathway includes both a classical and an alternative respiratory chain. The latter involves an alternative oxidase. Though the Plasmodium falciparum alternative oxidase is not yet identified, a specific inhibitor of this enzyme, salicylhydroxamic acid (SHAM), showed a drug effect on P. falciparum respiratory function using oxygen consumption measurements. The present study aimed to highlight the metabolic pathways that are affected in P. falciparum following SHAM exposure. DESIGN A proteomic approach was used to analyze the P. falciparum proteome and determine the metabolic pathways altered following SHAM treatment. To evaluate the SHAM effect on parasite growth, the phenotypic alterations of P. falciparum after SHAM or/and hyperoxia exposure were observed. RESULTS After SHAM exposure, 26 proteins were significantly deregulated using a fluorescent two dimensional-differential gel electrophoresis. Among these deregulated proteins, some were particularly involved in energetic metabolism. And the combinatory effect of SHAM/hyperoxia seems deleterious for the growth of P. falciparum. CONCLUSION Our results indicated that SHAM appears to activate glycolysis and decrease stress defense systems. These data provide a better understanding of parasite biology.
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Affiliation(s)
| | - Lionel Almeras
- Unité de Recherche en Biologie et Epidémiologie Parasitaires, Antenne IRBA de Marseille (IMTSSA, Le Pharo)
| | - Christelle Travaillé
- UMR-MD3, Université de la Méditerranée, Antenne IRBA de Marseille (IMTSSA, Le Pharo),
| | - Véronique Sinou
- UMR-MD3, Université de la Méditerranée, Antenne IRBA de Marseille (IMTSSA, Le Pharo),
| | - Matthieu Pophillat
- Centre d'Immunologie de Marseille Luminy, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de la Méditerranée
| | - Maya Belghazi
- Centre d'Analyse Protéomique de Marseille, Institut Fédératif de Recherche Jean Roche, Faculté de Médecine Nord
| | - Patrick Fourquet
- Centre d'Immunologie de Marseille Luminy, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de la Méditerranée
| | - Yves Jammes
- UMR-MD2, Physiologie et Physiopathologie en Conditions d'Oxygénations Extrêmes, Institut Fédératif de Recherche Jean Roche, Faculté de Médecine Nord, Marseille, France
| | - Daniel Parzy
- UMR-MD3, Université de la Méditerranée, Antenne IRBA de Marseille (IMTSSA, Le Pharo),
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11
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OHASHI-SUZUKI M, YABU Y, OHSHIMA S, NAKAMURA K, KIDO Y, SAKAMOTO K, KITA K, OHTA N, SUZUKI T. Differential Kinetic Activities of Glycerol Kinase among African Trypanosome Species: Phylogenetic and Therapeutic Implications. J Vet Med Sci 2011; 73:615-21. [DOI: 10.1292/jvms.10-0481] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Mitsuko OHASHI-SUZUKI
- Department of International Health Development, Division of Public Health, Graduate School of Tokyo Medical and Dental University
| | | | - Shigeru OHSHIMA
- Department of Core Laboratory, Nagoya City University Graduate School of Medical Sciences
| | - Kosuke NAKAMURA
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo
| | - Yasutoshi KIDO
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo
| | - Kimitoshi SAKAMOTO
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo
| | - Kiyoshi KITA
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo
| | - Nobuo OHTA
- Department of International Health Development, Division of Public Health, Graduate School of Tokyo Medical and Dental University
| | - Takashi SUZUKI
- Department of International Health Development, Division of Public Health, Graduate School of Tokyo Medical and Dental University
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12
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Ohshima S, Ohashi-Suzuki M, Miura Y, Yabu Y, Okada N, Ohta N, Suzuki T. TbUNC119 and its binding protein complex are essential for propagation, motility, and morphogenesis of Trypanosoma brucei procyclic form cells. PLoS One 2010; 5:e15577. [PMID: 21203515 PMCID: PMC3008729 DOI: 10.1371/journal.pone.0015577] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 11/15/2010] [Indexed: 01/13/2023] Open
Abstract
Flagellum-mediated motility of Trypanosoma brucei is considered to be essential for the parasite to complete stage development in the tsetse fly vector, while the mechanism by which flagellum-mediated motility is controlled are not fully understood. We thus compared T. brucei whole gene products (amino acid sequence) with Caenorhabditis elegans UNC (uncoordinated) proteins, in order to find uncharacterized motility-related T. brucei genes. Through in silico analysis, we found 88 gene products which were highly similar to C. elegans UNC proteins and categorized them as TbCEUN (T. brucei gene products which have high similarity to C. elegansUNC proteins). Approximately two thirds of the 88 TbCEUN gene products were kinesin-related molecules. A gene product highly similar to C. elegans UNC119 protein was designated as TbUNC119. RNAi-mediated depletion of TbUNC119 showed no apparent phenotype. However, knock-down analysis of both TbUNC119 and its binding protein (TbUNC119BP) which was found by yeast two-hybrid analysis showed characteristic phenotypes, including reduced motility, morphological change (extended cell shape), and cellular apoptosis. Based on the observed phenotypes, possible function of the TbUNC119 and TbUNC119BP is discussed.
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Affiliation(s)
- Shigeru Ohshima
- Department of Core Laboratory, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Department of Molecular Parasitology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Department of Immunology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Mitsuko Ohashi-Suzuki
- Department of Molecular Parasitology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Department of Immunology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Division of Public Health, Department of International Health Development, Graduate School of Tokyo Medical and Dental University, Tokyo, Japan
| | - Yutaka Miura
- Department of Molecular Neurology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Yoshisada Yabu
- Department of Immunology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Noriko Okada
- Department of Immunology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Nobuo Ohta
- Department of Molecular Parasitology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Division of Public Health, Department of International Health Development, Graduate School of Tokyo Medical and Dental University, Tokyo, Japan
| | - Takashi Suzuki
- Department of Molecular Parasitology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Department of Immunology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Division of Public Health, Department of International Health Development, Graduate School of Tokyo Medical and Dental University, Tokyo, Japan
- * E-mail:
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13
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Albury MS, Elliott C, Moore AL. Towards a structural elucidation of the alternative oxidase in plants. PHYSIOLOGIA PLANTARUM 2009; 137:316-27. [PMID: 19719482 DOI: 10.1111/j.1399-3054.2009.01270.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In addition to the conventional cytochrome c oxidase, mitochondria of all plants studied to date contain a second cyanide-resistant terminal oxidase or alternative oxidase (AOX). The AOX is located in the inner mitochondrial membrane and branches from the cytochrome pathway at the level of the quinone pool. It is non-protonmotive and couples the oxidation of ubiquinone to the reduction of oxygen to water. For many years, the AOX was considered to be confined to plants, fungi and a small number of protists. Recently, it has become apparent that the AOX occurs in wide range of organisms including prokaryotes and a moderate number of animal species. In this paper, we provide an overview of general features and current knowledge available about the AOX with emphasis on structure, the active site and quinone-binding site. Characterisation of the AOX has advanced considerably over recent years with information emerging about the role of the protein, regulatory regions and functional sites. The large number of sequences available is now enabling us to obtain a clearer picture of evolutionary origins and diversity.
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Affiliation(s)
- Mary S Albury
- Division of Biochemistry and Biomedical Sciences, School of Life Sciences, University of Sussex, Falmer, Brighton BN19QG, UK
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14
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McDonald AE, Vanlerberghe GC, Staples JF. Alternative oxidase in animals: unique characteristics and taxonomic distribution. ACTA ACUST UNITED AC 2009; 212:2627-34. [PMID: 19648408 DOI: 10.1242/jeb.032151] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Alternative oxidase (AOX), a ubiquinol oxidase, introduces a branch point into the respiratory electron transport chain, bypassing complexes III and IV and resulting in cyanide-resistant respiration. Previously, AOX was thought to be limited to plants and some fungi and protists but recent work has demonstrated the presence of AOX in most kingdoms of life, including animals. In the present study we identified AOX in 28 animal species representing nine phyla. This expands the known taxonomic distribution of AOX in animals by 10 species and two phyla. Using bioinformatics we found AOX gene sequences in members of the animal phyla Porifera, Placozoa, Cnidaria, Mollusca, Annelida, Nematoda, Echinodermata, Hemichordata and Chordata. Using reverse-transcriptase polymerase chain reaction (RT-PCR) with degenerate primers designed to recognize conserved regions of animal AOX, we demonstrated that AOX genes are transcribed in several animals from different phyla. An analysis of full-length AOX sequences revealed an amino acid motif in the C-terminal region of the protein that is unique to animal AOXs. Animal AOX also lacks an N-terminal cysteine residue that is known to be important for AOX enzyme regulation in plants. We conclude that the presence of AOX is the ancestral state in animals and hypothesize that its absence in some lineages, including vertebrates, is due to gene loss events.
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Affiliation(s)
- Allison E McDonald
- Department of Biology, The University of Western Ontario, London, Ontario, Canada N6A 5B7.
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15
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Antibiotics LL-Z1272 identified as novel inhibitors discriminating bacterial and mitochondrial quinol oxidases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:129-33. [DOI: 10.1016/j.bbabio.2008.11.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Revised: 11/21/2008] [Accepted: 11/26/2008] [Indexed: 11/19/2022]
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16
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Further insights into the structure of the alternative oxidase: from plants to parasites. Biochem Soc Trans 2008; 36:1022-6. [PMID: 18793182 DOI: 10.1042/bst0361022] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The AOX (alternative oxidase) is a non-protonmotive ubiquinol-oxygen oxidoreductase that couples the oxidation of ubiquinol with the complete reduction of water. Although it has long been recognized that it is ubiquitous among the plant kingdom, it has only recently become apparent that it is also widely found in other organisms including some human parasites. In this paper, we review experimental studies that have contributed to our current understanding of its structure, with particular reference to the catalytic site. Furthermore, we propose a model for the ubiquinol-binding site which identifies a hydrophobic pocket, between helices II and III, leading from a proposed membrane-binding domain to the catalytic domain.
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17
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Chaudhuri M, Ott RD, Hill GC. Trypanosome alternative oxidase: from molecule to function. Trends Parasitol 2006; 22:484-91. [PMID: 16920028 DOI: 10.1016/j.pt.2006.08.007] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Revised: 07/06/2006] [Accepted: 08/04/2006] [Indexed: 10/24/2022]
Abstract
Trypanosome alternative oxidase (TAO) is the cytochrome-independent terminal oxidase of the mitochondrial electron transport chain. TAO is a diiron protein that transfers electrons from ubiquinol to oxygen, reducing the oxygen to water. The mammalian bloodstream forms of Trypanosoma brucei depend solely on TAO for respiration. The inhibition of TAO by salicylhydroxamic acid (SHAM) or ascofuranone is trypanocidal. TAO is present at a reduced level in the procyclic form of T. brucei, where it is engaged in respiration and is also needed for developmental processes. Alternative oxidases similar to TAO have been found in a wide variety of organisms but not in mammals, thus rendering TAO an important chemotherapeutic target for African trypanosomiasis.
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Affiliation(s)
- Minu Chaudhuri
- Division of Microbial Pathogenesis and Immune Response, Department of Biomedical Sciences, Meharry Medical College, Nashville, TN 37208, USA.
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18
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Yabu Y, Suzuki T, Nihei CI, Minagawa N, Hosokawa T, Nagai K, Kita K, Ohta N. Chemotherapeutic efficacy of ascofuranone in Trypanosoma vivax-infected mice without glycerol. Parasitol Int 2005; 55:39-43. [PMID: 16288933 DOI: 10.1016/j.parint.2005.09.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2005] [Accepted: 09/09/2005] [Indexed: 10/25/2022]
Abstract
Ascofuranone, an antibiotic isolated from Ascochyta visiae, showed trypanocidal activity in Trypanosoma vivax-infected mice. A single dose of 50 mg/kg ascofuranone effectively cured the mice without the help of glycerol. Repeated administrations of this drug further enhanced its chemotherapeutic effect. After two, three, and four consecutive days treatment, the doses needed to cure the infection decreased to 25, 12, and 6 mg/kg, so that the total doses administered were 50, 36 and 24 mg/kg, respectively. Ascofuranone (50 mg/kg) also had a prophylactic effect against T. vivax infection within the first two days after administration. This prophylactic activity diminished to 80% by day 3 and completely disappeared four days after administration. Of particular interest in this study was that ascofuranone had trypanocidal activity in T. vivax-infected mice in the absence of glycerol, whereas co-administration of glycerol or repeated administrations of this drug are needed for Trypanosoma brucei brucei infection. Our present results strongly suggest that ascofuranone is also an effective tool in chemotherapy against African trypanosomiasis in domestic animals.
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Affiliation(s)
- Yoshisada Yabu
- Department of Molecular Parasitology, Nagoya City University, Graduate School of Medical Sciences, Nagoya 467-8601, Japan.
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19
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Suzuki T, Hashimoto T, Yabu Y, Majiwa PAO, Ohshima S, Suzuki M, Lu S, Hato M, Kido Y, Sakamoto K, Nakamura K, Kita K, Ohta N. Alternative oxidase (AOX) genes of African trypanosomes: phylogeny and evolution of AOX and plastid terminal oxidase families. J Eukaryot Microbiol 2005; 52:374-81. [PMID: 16014016 DOI: 10.1111/j.1550-7408.2005.00050.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To clarify evolution and phylogenetic relationships of trypanosome alternative oxidase (AOX) molecules, AOX genes (cDNAs) of the African trypanosomes, Trypanosoma congolense and Trypanosoma evansi, were cloned by PCR. Both AOXs possess conserved consensus motifs (-E-, -EXXH-). The putative amino acid sequence of the AOX of T. evansi was exactly the same as that of T. brucei. A protein phylogeny of trypanosome AOXs revealed that three genetically and pathogenically distinct strains of T. congolense are closely related to each other. When all known AOX sequences collected from current databases were analyzed, the common ancestor of these three Trypanosoma species shared a sister-group position to T. brucei/T. evansi. Monophyly of Trypanosoma spp. was clearly supported (100% bootstrap value) with Trypanosoma vivax placed at the most basal position of the Trypanosoma clade. Monophyly of other eukaryotic lineages, terrestrial plants + red algae, Metazoa, diatoms, Alveolata, oomycetes, green algae, and Fungi, was reconstructed in the best AOX tree obtained from maximum likelihood analysis, although some of these clades were not strongly supported. The terrestrial plants + red algae clade showed the closest affinity with an alpha-proteobacterium, Novosphingobium aromaticivorans, and the common ancestor of these lineages, was separated from other eukaryotes. Although the root of the AOX subtree was not clearly determined, subsequent phylogenetic analysis of the composite tree for AOX and plastid terminal oxidase (PTOX) demonstrated that PTOX and related cyanobacterial sequences are of a monophyletic origin and their common ancestor is linked to AOX sequences.
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Affiliation(s)
- Takashi Suzuki
- Department of Molecular Parasitology, Nagoya City University, Graduate School of Medical Sciences, Kawasumi, Mizuho 467-8601 Nagoya, Japan.
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20
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Ali Shah ST, Merkel P, Ragge H, Duszenko M, Rademann J, Voelter W. Stereospecific Synthesis of Chiral 2,3-Dihydro-1,4-benzodithiine and Methyl-2,3-dihydro-1,4-benzodithiine Derivatives and their Toxic Effects on Trypanosoma brucei. Chembiochem 2005; 6:1438-41. [PMID: 16052614 DOI: 10.1002/cbic.200400375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Preparation of chiral 2,3-dihydro-1,4-benzodithiine and methyl-2,3-dihydro-1,4-benzodithiine derivatives with known absolute configurations from the easily accessible chiral synthons benzyl 4-O-trifloxy-2,3-anhydro-beta-L-ribopyranoside and benzyl 4-O-trifloxy-2,3-anhydro-alpha-D-ribopyranoside is described. These compounds showed significant in vitro toxicity of the bloodstream form of Trypanosoma brucei with an IC50 of 11 microM. The parasites' energy metabolism and consumption of oxygen were found to be affected during incubation.
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Affiliation(s)
- Syed Tasadaque Ali Shah
- Physiologisch-chemisches Institut der Universität Tübingen, Hoppe-Seyler Strasse 4, 72076 Tübingen, Germany
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21
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Nakamura K, Sakamoto K, Kido Y, Fujimoto Y, Suzuki T, Suzuki M, Yabu Y, Ohta N, Tsuda A, Onuma M, Kita K. Mutational analysis of the Trypanosoma vivax alternative oxidase: The E(X)6Y motif is conserved in both mitochondrial alternative oxidase and plastid terminal oxidase and is indispensable for enzyme activity. Biochem Biophys Res Commun 2005; 334:593-600. [PMID: 16009344 DOI: 10.1016/j.bbrc.2005.06.131] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Accepted: 06/23/2005] [Indexed: 11/16/2022]
Abstract
Based on amino acid sequence similarity and the ability to catalyze the four-electron reduction of oxygen to water using a quinol substrate, mitochondrial alternative oxidase (AOX) and plastid terminal oxidase (PTOX) appear to be two closely related members of the membrane-bound diiron carboxylate group of proteins. In the current studies, we took advantage of the high activity of Trypanosoma vivax AOX (TvAOX) to examine the importance of the conserved Glu and the Tyr residues around the predicted third helix region of AOXs and PTOXs. We first compared the amino acid sequences of TvAOX with AOXs and PTOXs from various taxa and then performed alanine-scanning mutagenesis of TvAOX between amino acids Y(199) and Y(247). We found that the ubiquinol oxidase activity of TvAOX is completely lost in the E214A mutant, whereas mutants E215A and E216A retained more than 30% of the wild-type activity. Among the Tyr mutants, a complete loss of activity was also observed for the Y221A mutant, whereas the activities were equivalent to wild-type for the Y199A, Y212A, and Y247A mutants. Finally, residues Glu(214) and Tyr(221) were found to be strictly conserved among AOXs and PTOXs. Based on these findings, it appears that AOXs and PTOXs are a novel subclass of diiron carboxylate proteins that require the conserved motif E(X)(6)Y for enzyme activity.
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Affiliation(s)
- Kosuke Nakamura
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
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