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Choi G, Ahmad J, Navarro V, Thung S, Khan I, Avula B, Barnhart H, Stolz A. Characterisation of an outbreak of acute liver injury after ingestion of plant-based food supplement. Aliment Pharmacol Ther 2024; 60:479-483. [PMID: 38874448 PMCID: PMC11587764 DOI: 10.1111/apt.18116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/07/2024] [Accepted: 06/02/2024] [Indexed: 06/15/2024]
Abstract
BACKGROUND In April 2022, French Lentil and Leek Crumble (FLLC), a new frozen food preparation manufactured by Daily Harvest™ (containing Tara flour) was offered as a natural high-protein meal product. Soon thereafter, widespread anecdotal reports of acute gastrointestinal symptoms with liver injury were reported, leading to its voluntary withdrawal in June 2022, after shipment of 28,000 preparations. AIMS To summarise the clinical and laboratory features of 17 patients with FLLC associated liver injury from the Drug Induced Liver Injury Network (DILIN). METHODS Patients with FLLC-associated liver injury were enrolled into a prospective protocol and followed for 6 months. Cases were adjudicated by expert opinion causality assessment with summary statistics for data analysis. RESULTS Enrolled subjects had a mean age of 41 years, 82% were female with mean BMI of 24 kg/m2. All were Caucasian without underlying liver disease. In most cases, abdominal pain and nausea arose within hours of FLLC ingestion. Mean days from ingestion to identification of liver injury was 3.1 days (±2.8). On enrolment, 53% had jaundice, 47% nausea, 24% fever, 59% abdominal pain, 41% itching and 12% rash. The mean initial serum ALT was 475 U/L (±302), AST 315 U/L (±315), alkaline phosphatase 190 U/L (±76), with a total bilirubin of 2.6 mg/dL (±2). In this study, 63% presented with a hepatocellular pattern of liver injury, 6% cholestatic and 31% mixed as determined by the R value. In addition, 24% of patients were hospitalised, and there were no fatalities or liver transplants. Liver biopsy in one subject revealed acute hepatitis with mild ductular reaction, mild lymphocytic and eosinophilic portal inflammation, mild lobular inflammation, preserved bile ducts and absence of interface hepatitis, steatosis, granulomatous reaction or cholestasis. Phylogenetic analysis confirmed the presence of Tara spinosa, the source of Tara flour. CONCLUSIONS Natural food products are increasingly ubiquitous and may unexpectedly cause significant illness. All clinicians should inquire whether patients are consuming natural food products or herbal supplements and consider them as a potential cause of liver injury.
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Affiliation(s)
- Gina Choi
- David Geffen School of Medicine, University of California, Los Angeles
| | | | | | - Swan Thung
- Icahn School of Medicine, Mt. Sinai Health
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2
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Bhowal P, Roy B, Ganguli S, Igloi GL, Banerjee R. Elucidating the structure-function attributes of a trypanosomal arginyl-tRNA synthetase. Mol Biochem Parasitol 2023; 256:111597. [PMID: 37852416 DOI: 10.1016/j.molbiopara.2023.111597] [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: 08/06/2023] [Revised: 09/20/2023] [Accepted: 10/10/2023] [Indexed: 10/20/2023]
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are fundamental components of the protein translation machinery. In light of their pivotal role in protein synthesis and structural divergence among species, they have always been considered potential targets for the development of antimicrobial compounds. Arginyl-tRNA synthetase from Trypanosoma cruzi (TcArgRS), the parasite responsible for causing Chagas Disease, contains a 100-amino acid insertion that was found to be completely absent in the human counterpart of similar length, as ascertained from multiple sequence alignment results. Thus, we were prompted to perform a preliminary characterization of TcArgRS using biophysical, biochemical, and bioinformatics tools. We expressed the protein in E. coli and validated its in-vitro enzymatic activity. Additionally, analysis of DTNB kinetics, Circular dichroism (CD) spectra, and ligand-binding studies using intrinsic tryptophan fluorescence measurements aided us to understand some structural features in the absence of available crystal structures. Our study indicates that TcArgRS can discriminate between L-arginine and its analogues. Among the many tested substrates, only L-canavanine and L-thioarginine, a synthetic arginine analogue exhibited notable activation. The binding of various substrates was also determined using in silico methods. This study may provide a viable foundation for studying small compounds that can be targeted against TcArgRS.
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Affiliation(s)
- Pratyasha Bhowal
- Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700 019, India
| | - Bappaditya Roy
- Department of Microbiology, The Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Sayak Ganguli
- Post Graduate Department of Biotechnology, St. Xavier's College (Autonomous), 30, Park Street, Mullick Bazar, Kolkata 700 016, India.
| | - Gabor L Igloi
- Institute of Biology III, University of Freiburg, Schänzlestr 1, D-79104 Freiburg, Germany
| | - Rajat Banerjee
- Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700 019, India.
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3
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Antibacterial and Antibiofilm Effects of Allelopathic Compounds Identified in Medicago sativa L. Seedling Exudate against Escherichia coli. Molecules 2023; 28:molecules28062645. [PMID: 36985619 PMCID: PMC10056293 DOI: 10.3390/molecules28062645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 03/10/2023] [Accepted: 03/11/2023] [Indexed: 03/17/2023] Open
Abstract
In this study, the allelopathic properties of Medicago sativa L. (alfalfa) seedling exudates on the germination of seeds of various species were investigated. The compounds responsible for the allelopathic effects of alfalfa were identified and characterized by employing liquid chromatography ion mobility high-resolution mass spectrometry. Crude exudates inhibited the germination of seeds of all various plant species tested. Overall, nine compounds in alfalfa were identified and quantified. The most predominant compounds were a hyperoside representing a flavonoid glucoside, the non-proteinogenic amino acid canavanine, and two dipeptides, identified as H-Glu-Tyr-OH and H-Phe-Glu-OH. The latter corresponds to the first finding that dipeptides are exuded from alfalfa seedlings. In addition, the antibacterial and antibiofilm activities of alfalfa exudate and its identified compounds were elucidated. Both hyperoside and canavanine revealed the best antibacterial activity with minimum inhibitory concentration (MIC) values that ranged from 8 to 32 and 32 to 256 µg/mL, respectively. Regarding the antibiofilm action, hyperoside and canavanine caused a decline in the percentage of E. coli isolates that possessed a strong and moderate biofilm-forming potential from 68.42% to 21.05% and 31.58%, respectively. Studies on their inhibiting effects exhibit that these major substances are predominantly responsible for the allelopathic and antimicrobial effects of the crude exudates.
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Hlongwane MM, Mohammed M, Mokgalaka NS, Dakora FD. The Potential of Rhizobacteria to Mitigate Abiotic Stress in Lessertia frutescens. PLANTS (BASEL, SWITZERLAND) 2023; 12:196. [PMID: 36616325 PMCID: PMC9824651 DOI: 10.3390/plants12010196] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 06/17/2023]
Abstract
Lessertia frutescens is a multipurpose medicinal plant indigenous to South Africa. The curative ability of the medicinal plant is attributed to its rich phytochemical composition, including amino acids, triterpenoids, and flavonoids. A literature review of some of the phytochemical compounds, particularly amino acids, in L. frutescens shows a steady decrease in concentration over the years. The reduction of the phytochemical compounds and diminishing biological activities may be attributed to drought and salt stress, which South Africa has been grappling with over the years. Canavanine, a phytochemical which is associated with the anticancer activity of L. frutescens, reduced slightly when the plant was subjected to salt stress. Like other legumes, L. frutescens forms a symbiotic relationship with plant-growth-promoting rhizobacteria, which facilitate plant growth and development. Studies employing commercial plant-growth-promoting rhizobacteria to enhance growth and biological activities in L. frutescens have been successfully carried out. Furthermore, alleviation of drought and salt stress in medicinal plants through inoculation with plant growth-promoting-rhizobacteria is well documented and effective. Therefore, this review seeks to highlight the potential of plant-growth-promoting rhizobacteria to alleviate the effect of salt and drought in Lessertia frutescens.
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Affiliation(s)
- Mokgadi M. Hlongwane
- Department of Chemistry, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa
| | - Mustapha Mohammed
- Department of Crop Science, University for Development Studies, Tamale P.O. Box TL1882, Ghana
| | - Ntebogeng S. Mokgalaka
- Department of Chemistry, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa
- Mamelodi Campus, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa
| | - Felix D. Dakora
- Department of Chemistry, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa
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5
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Characterization of canavanine-resistance of cat1 and vhc1 deletions and a dominant any1 mutation in fission yeast. PLoS One 2022; 17:e0269276. [PMID: 35639710 PMCID: PMC9154178 DOI: 10.1371/journal.pone.0269276] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 05/17/2022] [Indexed: 11/20/2022] Open
Abstract
Positive and counter-selectable markers have been successfully integrated as a part of numerous genetic assays in many model organisms. In this study, we investigate the mechanism of resistance to arginine analog canavanine and its applicability for genetic selection in Schizosaccharomyces pombe. Deletion of both the arginine permease gene cat1 and SPBC18H10.16/vhc1 (formerly mistakenly called can1) provides strong drug resistance, while the single SPBC18H10.16/vhc1 deletion does not have an impact on canavanine resistance. Surprisingly, the widely used can1-1 allele does not encode for a defective arginine permease but rather corresponds to the any1-523C>T allele. The strong canavanine-resistance conferred by this allele arises from an inability to deposit basic amino acid transporters on the cellular membrane. any1-523C>T leads to reduced post-translational modifications of Any1 regulated by the Tor2 kinase. We also demonstrate that any1-523C>T is a dominate allele. Our results uncover the mechanisms of canavanine-resistance in fission yeast and open the opportunity of using cat1, vhc1 and any1 mutant alleles in genetic assays.
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6
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Khan K, Gogonea V, Fox PL. Aminoacyl-tRNA synthetases of the multi-tRNA synthetase complex and their role in tumorigenesis. Transl Oncol 2022; 19:101392. [PMID: 35278792 PMCID: PMC8914993 DOI: 10.1016/j.tranon.2022.101392] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/27/2022] [Accepted: 02/28/2022] [Indexed: 12/16/2022] Open
Abstract
In mammalian cells, 20 aminoacyl-tRNA synthetases (AARS) catalyze the ligation of amino acids to their cognate tRNAs to generate aminoacylated-tRNAs. In higher eukaryotes, 9 of the 20 AARSs, along with 3 auxiliary proteins, join to form the cytoplasmic multi-tRNA synthetase complex (MSC). The complex is absent in prokaryotes, but evolutionary expansion of MSC constituents, primarily by addition of novel interacting domains, facilitates formation of subcomplexes that join to establish the holo-MSC. In some cases, environmental cues direct the release of constituents from the MSC which enables the execution of non-canonical, i.e., "moonlighting", functions distinct from their essential activities in protein translation. These activities are generally beneficial, but can also be deleterious to the cell. Elucidation of the non-canonical activities of several AARSs residing in the MSC suggest they are potential therapeutic targets for cancer, as well as metabolic and neurologic diseases. Here, we describe the role of MSC-resident AARSs in cancer progression, and the factors that regulate their release from the MSC. Also, we highlight recent developments in therapeutic modalities that target MSC AARSs for cancer prevention and treatment.
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Affiliation(s)
- Krishnendu Khan
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, United States of America.
| | - Valentin Gogonea
- Department of Chemistry, Cleveland State University, Cleveland, OH 44115, United States of America
| | - Paul L Fox
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, United States of America.
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Mardani-Korrani H, Nakayasu M, Yamazaki S, Aoki Y, Kaida R, Motobayashi T, Kobayashi M, Ohkama-Ohtsu N, Oikawa Y, Sugiyama A, Fujii Y. L-Canavanine, a Root Exudate From Hairy Vetch ( Vicia villosa) Drastically Affecting the Soil Microbial Community and Metabolite Pathways. Front Microbiol 2021; 12:701796. [PMID: 34646244 PMCID: PMC8503639 DOI: 10.3389/fmicb.2021.701796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 08/30/2021] [Indexed: 12/30/2022] Open
Abstract
L-Canavanine, a conditionally essential non-proteinogenic amino acid analog to L-arginine, plays important roles in cell division, wound healing, immune function, the release of hormones, and a precursor for the synthesis of nitric oxide (NO). In this report, we found that the L-canavanine is released into the soil from the roots of hairy vetch (Vicia villosa) and declines several weeks after growth, while it was absent in bulk proxy. Hairy vetch root was able to exudate L-canavanine in both pots and in vitro conditions in an agar-based medium. The content of the L-canavanine in pots and agar conditions was higher than the field condition. It was also observed that the addition of L-canavanine significantly altered the microbial community composition and diversity in soil. Firmicutes and Actinobacteria became more abundant in the soil after the application of L-canavanine. In contrast, Proteobacteria and Acidobacteria populations were decreased by higher L-canavanine concentration (500 nmol/g soil). Prediction of the soil metabolic pathways using PICRUSt2 estimated that the L-arginine degradation pathway was enriched 1.3-fold when L-canavanine was added to the soil. Results indicated that carbon metabolism-related pathways were altered and the degradation of nitrogen-rich compounds (i.e., amino acids) enriched. The findings of this research showed that secretion of the allelochemical L-canavanine from the root of hairy vetch may alter the soil microbial community and soil metabolite pathways to increase the survival chance of hairy vetch seedlings. This is the first report that L-canavanine acts as an allelochemical that affects the biodiversity of soil microbial community.
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Affiliation(s)
| | - Masaru Nakayasu
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan
| | - Shinichi Yamazaki
- Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Yuichi Aoki
- Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Rumi Kaida
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Takashi Motobayashi
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | | | - Naoko Ohkama-Ohtsu
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Yosei Oikawa
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Akifumi Sugiyama
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan
| | - Yoshiharu Fujii
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
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8
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Jander G, Kolukisaoglu U, Stahl M, Yoon GM. Editorial: Physiological Aspects of Non-proteinogenic Amino Acids in Plants. FRONTIERS IN PLANT SCIENCE 2020; 11:519464. [PMID: 33391293 PMCID: PMC7773597 DOI: 10.3389/fpls.2020.519464] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 11/27/2020] [Indexed: 06/12/2023]
Affiliation(s)
- Georg Jander
- Boyce Thompson Institute, Ithaca, NY, United States
| | - Uener Kolukisaoglu
- Center for Plant Molecular Biology, University of Tuebingen, Tuebingen, Germany
| | - Mark Stahl
- Center for Plant Molecular Biology, University of Tuebingen, Tuebingen, Germany
| | - Gyeong Mee Yoon
- Department of Botany and Plant Pathology, Center for Plant Biology, Purdue University, West Lafayette, IN, United States
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9
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Chen O, Manig F, Lehmann L, Sorour N, Löck S, Yu Z, Dubrovska A, Baumann M, Kessler BM, Stasyk O, Kunz-Schughart LA. Dual role of ER stress in response to metabolic co-targeting and radiosensitivity in head and neck cancer cells. Cell Mol Life Sci 2020; 78:3021-3044. [PMID: 33230565 PMCID: PMC8004506 DOI: 10.1007/s00018-020-03704-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 10/19/2020] [Accepted: 11/04/2020] [Indexed: 12/12/2022]
Abstract
Arginine deprivation therapy (ADT) is a new metabolic targeting approach with high therapeutic potential for various solid cancers. Combination of ADT with low doses of the natural arginine analog canavanine effectively sensitizes malignant cells to irradiation. However, the molecular mechanisms determining the sensitivity of intrinsically non-auxotrophic cancers to arginine deficiency are still poorly understood. We here show for the first time that arginine deficiency is accompanied by global metabolic changes and protein/membrane breakdown, and results in the induction of specific, more or less pronounced (severe vs. mild) ER stress responses in head and neck squamous cell carcinoma (HNSCC) cells that differ in their intrinsic ADT sensitivity. Combination of ADT with canavanine triggered catastrophic ER stress via the eIF2α-ATF4(GADD34)-CHOP pathway, thereby inducing apoptosis; the same signaling arm was irrelevant in ADT-related radiosensitization. The particular strong supra-additive effect of ADT, canavanine and irradiation in both intrinsically more and less sensitive cancer cells supports the rational of ER stress pathways as novel target for improving multi-modal metabolic anti-cancer therapy.
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Affiliation(s)
- Oleg Chen
- OncoRay, National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstraße 74, 01307, Dresden, Germany.,Department of Cell Signaling, Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine
| | - Friederike Manig
- OncoRay, National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstraße 74, 01307, Dresden, Germany.,Chair of Food Chemistry, TU Dresden, Dresden, Germany
| | - Loreen Lehmann
- OncoRay, National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstraße 74, 01307, Dresden, Germany
| | - Nagwa Sorour
- OncoRay, National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstraße 74, 01307, Dresden, Germany
| | - Steffen Löck
- OncoRay, National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstraße 74, 01307, Dresden, Germany.,German Cancer Consortium (DKTK), Partner Site Dresden, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany.,Department of Radiation Oncology, University Hospital Carl Gustav Carus, Dresden, Germany
| | - Zhanru Yu
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Anna Dubrovska
- OncoRay, National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstraße 74, 01307, Dresden, Germany.,German Cancer Consortium (DKTK), Partner Site Dresden, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany.,Institute of Radiooncology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - Michael Baumann
- OncoRay, National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstraße 74, 01307, Dresden, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Benedikt M Kessler
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Oleh Stasyk
- Department of Cell Signaling, Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine
| | - Leoni A Kunz-Schughart
- OncoRay, National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Fetscherstraße 74, 01307, Dresden, Germany. .,National Center for Tumor Diseases (NCT), Partner Site Dresden, Germany.
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Turck D, Castenmiller J, De Henauw S, Hirsch‐Ernst KI, Kearney J, Maciuk A, Mangelsdorf I, McArdle HJ, Naska A, Pelaez C, Pentieva K, Siani A, Thies F, Tsabouri S, Vinceti M, Cubadda F, Engel KH, Frenzel T, Heinonen M, Marchelli R, Neuhäuser‐Berthold M, Poulsen M, Schlatter JR, van Loveren H, Ackerl R, Knutsen HK. Safety of a botanical extract derived from Panax notoginseng and Astragalus membranaceus (AstraGin™) as a novel food pursuant to Regulation (EU) 2015/2283. EFSA J 2020; 18:e06099. [PMID: 37649518 PMCID: PMC10464683 DOI: 10.2903/j.efsa.2020.6099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on a botanical extract derived from both Panax notoginseng and Astragalus membranaceus (AstraGin™) as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF is a combination of an ethanol extract of the roots of A. membranaceus and a hot water extract of the roots of P. notoginseng. The NF contains 1.5-5% total saponins, 0.1-0.5% ginsenoside Rb1 and 0.01-0.1% astragaloside I. Both plants that are used to produce the NF have a long history of use, especially in traditional Chinese medicine. Information on the production process and the composition of the NF is sufficient and does not raise safety concerns. The applicant proposed to use the NF as a food supplement for the general adult population, excluding pregnant women, at a maximum daily amount of 350 mg. Taking into account these conditions of use, the Panel considers that the consumption of the NF is not nutritionally disadvantageous. The provided genotoxicity studies do not raise concerns for genotoxicity of the NF. Based on the findings of a subchronic toxicity study, supported by a subacute toxicity study, the Panel identified the overall no observed adverse effect level (NOAEL) of the NF at 100 mg/kg body weight (bw) per day. By applying an uncertainty factor of 200, the Panel concludes that the NF is safe at an intake level of 0.5 mg/kg bw per day, corresponding to a maximum daily intake of 35 mg of the NF for the target population, i.e. adults excluding pregnant women.
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Wang J, Weng Q, Yin F, Hu Q. Interactions of Destruxin A with Silkworms' Arginine tRNA Synthetase and Lamin-C Proteins. Toxins (Basel) 2020; 12:toxins12020137. [PMID: 32098437 PMCID: PMC7076788 DOI: 10.3390/toxins12020137] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/18/2020] [Accepted: 02/21/2020] [Indexed: 12/21/2022] Open
Abstract
Destruxin A (DA), a cyclodepsipeptidic mycotoxin produced by entomopathogenic fungus Metarhizium anisopliae, has good insecticidal activity and potential to be a new pesticide. However, the mechanism of action is still obscure. Our previous experiments showed that DA was involved in regulation of transcription and protein synthesis and suggested that silkworms’ arginine tRNA synthetase (BmArgRS), Lamin-C Proteins (BmLamin-C) and ATP-dependent RNA helicase PRP1 (BmPRP1) were candidates of DA-binding proteins. In this study, we employed bio-layer interferometry (BLI), circular dichroism (CD), cellular thermal shift assay (CETSA), and other technologies to verify the interaction of DA with above three proteins in vitro and in vivo. The results of BLI indicated that BmArgRS and BmLamin-C were binding-protein of DA with KD value 5.53 × 10−5 and 8.64 × 10−5 M, but not BmPRP1. These interactions were also verified by CD and CETSA tests. In addition, docking model and mutants assay in vitro showed that BmArgRS interacts with DA at the pocket including Lys228, His231, Asp434 and Gln437 in its enzyme active catalysis region, while BmLamin-C binds to DA at His524 and Lys528 in the tail domain. This study might provide new insight and evidence in illustrating molecular mechanism of DA in breaking insect.
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12
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Smith ZM, Steinmetz V, Martens J, Oomens J, Poutsma JC. Infrared Multiple Photon Dissociation Spectroscopy of Cationized Canavanine: Side-Chain Substitution Influences Gas-Phase Zwitterion Formation †. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2018; 429:158-173. [PMID: 29962900 PMCID: PMC6020040 DOI: 10.1016/j.ijms.2017.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Infrared multiple photon dissociation spectroscopy was performed on protonated and cationized canavanine (Cav), a non-protein amino acid oxy-analog of arginine. Infrared spectra in the XH stretching region (3000 - 4000 cm-1) were obtained at the Centre Laser Infrarouge d'Orsay (CLIO) facility. Comparison of the experimental infrared spectra with scaled harmonic frequencies at the B3LYP/6-31+G(d,p) level of theory indicates that canavanine is in a canonical neutral form in CavH+, CavLi+, and CavNa+; therefore, these cations are charge-solvated structures. The infrared spectrum of CavK+ is consistent with a mixture of Cav in canonical and zwitterionic forms leading to both charge-solvated and salt-bridged cationic structures. The Cav moiety in CavCs+ is shown to be zwitterionic, forming a salt-bridged structure for the cation. Infrared spectra in the fingerprint region (1000 - 2000 cm-1) obtained at the FELIX Laboratory in Nijmegen, Netherlands support these assignments. These results show that that a single oxygen atom substitution in the side chain reduces the stability of the zwitterion compared to that of the protein amino acid arginine (Arg), which has been shown previously to adopt a zwitterionic structure in ArgNa+ and ArgK+. This difference can be explained in part due to the decreased basicity of Cav (PA = 1001 kJ/mol) as compared to arginine (PA = 1051 kJ/mol), but not entirely, as lysine, which has nearly the same proton affinity as Cav, (~993 kJ/mol) forms only canonical structures with Na+, K+, and Cs+. A major difference between the zwitterionic forms of ArgM+ and CavM+ is that the protonation site is on the side chain for Arg and on the N-terminus for Cav. This results in systematically weaker salt bridges in the Cav zwitterions. In addition, the presence of another hydrogen-bonding acceptor atom in the side chain contributes to the stability of the canonical structures for the smaller alkali cations.
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Affiliation(s)
- Zachary M Smith
- Department of Chemistry, The College of William and Mary, Williamsburg, VA 23187-8795
| | - Vincent Steinmetz
- Laboratoire de Chimie Physique, CNRS UMR 8000, Université Paris Sud, Université Paris Saclay, CNRS, Orsay France
| | - Jonathan Martens
- Radboud University, Institute for Molecules and Materials FELIX Laboratory, Nijmegen, The Netherlands
| | - Jos Oomens
- Radboud University, Institute for Molecules and Materials FELIX Laboratory, Nijmegen, The Netherlands
- Van't Hoff Institute for Molecular Sciences University of Amsterdam, Amsterdam, The Netherlands
| | - John C Poutsma
- Department of Chemistry, The College of William and Mary, Williamsburg, VA 23187-8795
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13
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Kurlishchuk Y, Vynnytska-Myronovska B, Grosse-Gehling P, Bobak Y, Manig F, Chen O, Merker SR, Henle T, Löck S, Stange DE, Stasyk O, Kunz LA. Co-application of canavanine and irradiation uncouples anticancer potential of arginine deprivation from citrulline availability. Oncotarget 2016; 7:73292-73308. [PMID: 27689335 PMCID: PMC5341980 DOI: 10.18632/oncotarget.12320] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 09/19/2016] [Indexed: 12/17/2022] Open
Abstract
The moderate anticancer effect of arginine deprivation in clinical trials has been linked to an induced argininosuccinate synthetase (ASS1) expression in initially ASS1-negative tumors, and ASS1-positive cancers are anticipated as non-responders. Our previous studies indicated that arginine deprivation and low doses of the natural arginine analog canavanine can enhance radioresponse. However, the efficacy of the proposed combination in the presence of extracellular citrulline, the substrate for arginine synthesis by ASS1, remains to be elucidated, in particular for malignant cells with positive and/or inducible ASS1 as in colorectal cancer (CRC). Here, the physiological citrulline concentration of 0.05 mM was insufficient to overcome cell cycle arrest and radiosensitization triggered by arginine deficiency. Hyperphysiological citrulline (0.4 mM) did not entirely compensate for the absence of arginine and significantly decelerated cell cycling. Similar levels of canavanine-induced apoptosis were detected in the absence of arginine regardless of citrulline supplementation both in 2-D and advanced 3-D assays, while normal colon epithelial cells in organoid/colonosphere culture were unaffected. Notably, canavanine tremendously enhanced radiosensitivity of arginine-starved 3-D CRC spheroids even in the presence of hyperphysiological citrulline. We conclude that the novel combinatorial targeting strategy of metabolic-chemo-radiotherapy has great potential for the treatment of malignancies with inducible ASS1 expression.
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Affiliation(s)
- Yuliya Kurlishchuk
- OncoRay–National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology, Dresden, Germany
- Department of Cell Signaling, Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine
| | - Bozhena Vynnytska-Myronovska
- OncoRay–National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology, Dresden, Germany
- Department of Cell Signaling, Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine
- Current address: Clinic of Urology and Pediatric Urology, Saarland University Medical Center, Homburg/Saar, Germany
| | - Philipp Grosse-Gehling
- OncoRay–National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology, Dresden, Germany
| | - Yaroslav Bobak
- Department of Cell Signaling, Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine
| | - Friederike Manig
- OncoRay–National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology, Dresden, Germany
- Institute of Food Chemistry, TU Dresden, Dresden, Germany
| | - Oleg Chen
- OncoRay–National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology, Dresden, Germany
- Department of Cell Signaling, Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine
| | - Sebastian R. Merker
- Department of Gastrointestinal, Thoracic and Vascular Surgery, University Hospital Carl Gustav Carus, TU Dresden, Dresden, Germany
| | - Thomas Henle
- Institute of Food Chemistry, TU Dresden, Dresden, Germany
| | - Steffen Löck
- OncoRay–National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology, Dresden, Germany
| | - Daniel E. Stange
- Department of Gastrointestinal, Thoracic and Vascular Surgery, University Hospital Carl Gustav Carus, TU Dresden, Dresden, Germany
| | - Oleh Stasyk
- Department of Cell Signaling, Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine
| | - Leoni A. Kunz
- OncoRay–National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden and Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology, Dresden, Germany
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford, UK
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14
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Worst EG, Exner MP, De Simone A, Schenkelberger M, Noireaux V, Budisa N, Ott A. Residue-specific Incorporation of Noncanonical Amino Acids into Model Proteins Using an Escherichia coli Cell-free Transcription-translation System. J Vis Exp 2016. [PMID: 27500416 PMCID: PMC5091720 DOI: 10.3791/54273] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The canonical set of amino acids leads to an exceptionally wide range of protein functionality. Nevertheless, the set of residues still imposes limitations on potential protein applications. The incorporation of noncanonical amino acids can enlarge this scope. There are two complementary approaches for the incorporation of noncanonical amino acids. For site-specific incorporation, in addition to the endogenous canonical translational machineries, an orthogonal aminoacyl-tRNA-synthetase-tRNA pair must be provided that does not interact with the canonical ones. Consequently, a codon that is not assigned to a canonical amino acid, usually a stop codon, is also required. This genetic code expansion enables the incorporation of a noncanonical amino acid at a single, given site within the protein. The here presented work describes residue-specific incorporation where the genetic code is reassigned within the endogenous translational system. The translation machinery accepts the noncanonical amino acid as a surrogate to incorporate it at canonically prescribed locations, i.e., all occurrences of a canonical amino acid in the protein are replaced by the noncanonical one. The incorporation of noncanonical amino acids can change the protein structure, causing considerably modified physical and chemical properties. Noncanonical amino acid analogs often act as cell growth inhibitors for expression hosts since they modify endogenous proteins, limiting in vivo protein production. In vivo incorporation of toxic noncanonical amino acids into proteins remains particularly challenging. Here, a cell-free approach for a complete replacement of L-arginine by the noncanonical amino acid L-canavanine is presented. It circumvents the inherent difficulties of in vivo expression. Additionally, a protocol to prepare target proteins for mass spectral analysis is included. It is shown that L-lysine can be replaced by L-hydroxy-lysine, albeit with lower efficiency. In principle, any noncanonical amino acid analog can be incorporated using the presented method as long as the endogenous in vitro translation system recognizes it.
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Affiliation(s)
| | | | | | | | | | | | - Albrecht Ott
- Department of Experimental Physics, Saarland University;
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15
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Effects of the combined arginase and canavanine treatment on leukemic cells in vitro and in vivo. UKRAINIAN BIOCHEMICAL JOURNAL 2016; 88:45-55. [DOI: 10.15407/ubj88.02.045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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16
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Nurcahyanti ADR, Wink M. Cytotoxic potentiation of vinblastine and paclitaxel by L-canavanine in human cervical cancer and hepatocellular carcinoma cells. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2015; 22:1232-1237. [PMID: 26655405 DOI: 10.1016/j.phymed.2015.10.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/15/2015] [Accepted: 10/20/2015] [Indexed: 06/05/2023]
Abstract
BACKGROUND The non-protein amino acid L-canavanine (L-CAV), found in several plants of the family Fabaceae is an antimetabolite which shows anticancer activity due to its ability to be incorporated into protein in the place of its analogue, L-arginine (L-ARG), leading to the alteration of the 3D conformation of newly synthesised proteins and usually a loss of their function. PURPOSE In this study, the ability of L-CAV to potentiate the cytotoxicity of microtubule- targeting drugs used in the chemotherapy of cancer, vinblastine (VIN) and paclitaxel (PTX) was evaluated. MATERIAL AND METHODS The following cancer cells grown in arginine-rich and arginine-free media were employed: HeLa, Hep G2 and SK-HEP-1. Drug combination experiment used a method based on the median-effect principle and mass-action law. RESULTS We observed that L-CAV, which is hardly toxic alone, potentiated the cytotoxicity of VIN and PTX in HeLa and hepatocellular carcinoma cells. CONCLUSION This is the first study showing the cytotoxic potentiation of microtubule-targeting drugs by L-CAV. The mechanism of synergy and animal studies need to be investigated further to see whether L-CAV might become an adjuvant in cancer treatment.
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Affiliation(s)
- Agustina D R Nurcahyanti
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany.
| | - Michael Wink
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany.
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17
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Worst EG, Exner MP, De Simone A, Schenkelberger M, Noireaux V, Budisa N, Ott A. Cell-free expression with the toxic amino acid canavanine. Bioorg Med Chem Lett 2015; 25:3658-60. [DOI: 10.1016/j.bmcl.2015.06.045] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 06/12/2015] [Accepted: 06/13/2015] [Indexed: 01/29/2023]
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18
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Function of MsiR on canavanine-mediated repression in Mesorhizobium tianshanense. Arch Microbiol 2015; 197:729-35. [PMID: 25854984 DOI: 10.1007/s00203-015-1106-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 09/16/2014] [Accepted: 03/16/2015] [Indexed: 10/23/2022]
Abstract
Mesorhizobium tianshanense employs MsiA as canavanine exporter, which is upregulated by MsiR, to successfully form a symbiosis with the legume Glycyrrhiza uralensis. In this research, through gel-shift and bacterial two-hybrid examination, MsiR was found to spontaneously form dimers and bind to msiA promoter without additional canavanine. Six truncated forms of MsiR were constructed, and the conserved helix-turn-helix (HTH), substrate-binding, and surface-loop domains were found essential for MsiR functions. Random mutagenesis was used to study the functional sites of MsiR. Seven point mutants were selected, in which three mutants constitutively induced msiA expression without additional canavanine, two mutants partially changed substrate specificity, and the other two were almost null mutants. Results from the site mutation show that the functional subunits (HTH domain, dimerization interface domains, and C-terminal) are important in the conformation and induction ability of MsiR.
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19
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Barón-Sola Á, Sanz-Alférez S, Del Campo FF. First evidence of accumulation in cyanobacteria of guanidinoacetate, a precursor of the toxin cylindrospermopsin. CHEMOSPHERE 2015; 119:1099-1104. [PMID: 25460748 DOI: 10.1016/j.chemosphere.2014.08.046] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 07/17/2014] [Accepted: 08/19/2014] [Indexed: 06/04/2023]
Abstract
Guanidinoacetate (GAA) is one of the most extensively studied toxic guanidine compounds. Changes in GAA can affect the nervous system and induce hyperhomocysteinemia, representing a risk factor for cardiovascular diseases. In cyanobacteria, GAA is thought to be an intermediate in the synthesis of the toxin cylindrospermopsin (CYN), one of the most common known cyanotoxins that affects multiple organs and functions in animals and plants. In spite of the evidence supporting GAA toxicity and its role in CYN synthesis, no data have been reported on the accumulation of GAA in any cyanobacterium. We have analyzed and compared the content of GAA in cultures of diverse cyanobacteria types, both cylindrospermopsin producing (CYN(+)) and not producing (CYN(-)). The results obtained show that GAA accumulates in the majority of the strains tested, although the highest content was found in one of the CYN(+) strain, Aphanizomenon ovalisporum UAM-MAO. In this strain, both GAA and CYN can be located within and out the cells. In conclusion, GAA appears to be a general cyanobacterial metabolite that due to its proven toxic should be considered when studying and managing cyanobacteria toxicity.
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Affiliation(s)
- Ángel Barón-Sola
- Departamento de Biología, C/Darwin 2, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Soledad Sanz-Alférez
- Departamento de Biología, C/Darwin 2, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Francisca F Del Campo
- Departamento de Biología, C/Darwin 2, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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20
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Kim HS, Cha SY, Jo CH, Han A, Hwang KY. The crystal structure of arginyl-tRNA synthetase fromHomo sapiens. FEBS Lett 2014; 588:2328-34. [DOI: 10.1016/j.febslet.2014.05.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 05/12/2014] [Accepted: 05/12/2014] [Indexed: 10/25/2022]
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21
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Danchin A, Sekowska A. The logic of metabolism and its fuzzy consequences. Environ Microbiol 2013; 16:19-28. [PMID: 24387040 DOI: 10.1111/1462-2920.12270] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 08/02/2013] [Accepted: 08/26/2013] [Indexed: 12/26/2022]
Abstract
Intermediary metabolism molecules are orchestrated into logical pathways stemming from history (L-amino acids, D-sugars) and dynamic constraints (hydrolysis of pyrophosphate or amide groups is the driving force of anabolism). Beside essential metabolites, numerous variants derive from programmed or accidental changes. Broken down, variants enter standard pathways, producing further variants. Macromolecule modification alters enzyme reactions specificity. Metabolism conform thermodynamic laws, precluding strict accuracy. Hence, for each regular pathway, a wealth of variants inputs and produces metabolites that are similar to but not the exact replicas of core metabolites. As corollary, a shadow, paralogous metabolism, is associated to standard metabolism. We focus on a logic of paralogous metabolism based on diversion of the core metabolic mimics into pathways where they are modified to minimize their input in the core pathways where they create havoc. We propose that a significant proportion of paralogues of well-characterized enzymes have evolved as the natural way to cope with paralogous metabolites. A second type of denouement uses a process where protecting/deprotecting unwanted metabolites - conceptually similar to the procedure used in the laboratory of an organic chemist - is used to enter a completely new catabolic pathway.
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Affiliation(s)
- Antoine Danchin
- Building G1, AMAbiotics SAS, 2 rue Gaston Crémieux, Evry, 91000, France
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22
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Wheeler HE, Gamazon ER, Stark AL, O'Donnell PH, Gorsic LK, Huang RS, Cox NJ, Dolan ME. Genome-wide meta-analysis identifies variants associated with platinating agent susceptibility across populations. THE PHARMACOGENOMICS JOURNAL 2011; 13:35-43. [PMID: 21844884 PMCID: PMC3370147 DOI: 10.1038/tpj.2011.38] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Platinating agents are used in the treatment of many cancers, yet they can induce toxicities and resistance that limit their utility. Using previously published and additional world population panels of diverse ancestry totaling 608 lymphoblastoid cell lines (LCLs), we performed meta-analyses of over 3 million SNPs for both carboplatin- and cisplatin-induced cytotoxicity. The most significant SNP in the carboplatin meta-analysis is located in an intron of NBAS (p = 5.1 × 10−7). The most significant SNP in the cisplatin meta-analysis is upstream of KRT16P2 (p = 5.8 × 10−7). We also show that cisplatin-susceptibility SNPs are enriched for carboplatin-susceptibility SNPs. Most of the variants that associate with platinum-induced cytotoxicity are polymorphic across multiple world populations; therefore, they could be tested in follow-up studies in diverse clinical populations. Seven genes previously implicated in platinating agent response, including BCL2, GSTM1, GSTT1, ERCC2, and ERCC6 were also implicated in our meta-analyses.
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Affiliation(s)
- H E Wheeler
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
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23
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Vynnytska-Myronovska B, Bobak Y, Garbe Y, Dittfeld C, Stasyk O, Kunz-Schughart LA. Single amino acid arginine starvation efficiently sensitizes cancer cells to canavanine treatment and irradiation. Int J Cancer 2011; 130:2164-75. [PMID: 21647872 DOI: 10.1002/ijc.26221] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 05/24/2011] [Indexed: 01/25/2023]
Abstract
Single amino acid arginine deprivation is a promising strategy in modern metabolic anticancer therapy. Its potency to inhibit tumor growth warrants the search for rational chemo- and radio-therapeutic approaches to be co-applied. In this report, we evaluated, for the first time, the efficacy of arginine deprivation as anticancer therapy in three-dimensional (3D) cultures of human tumor cells, and propose a new combinatorial metabolic-chemo-radio-treatment regime based on arginine starvation, low doses of arginine natural analog canavanine and irradiation. A sophisticated experimental setup was designed to evaluate the impact of arginine starvation on four human epithelial cancer cell lines in 2D monolayer and 3D spheroid culture. Radioresponse was assessed in colony formation assays and by monitoring spheroid regrowth probability following single dose irradiation using a standardized spheroid-based test platform. Surviving fraction at 2 Gy (SF(2Gy)) and spheroid control dose(50) (SCD(50) ) were calculated as analytical endpoints. Cancer cells in spheroids are much more resistant to arginine starvation than in 2D culture. Spheroid volume stagnated during arginine deprivation, but even after 10 days of starvation, 100% of the spheroids regrew. Combination treatment, however, was remarkably efficient. In particular, pretreatment of cancer cells with the arginine-degrading enzyme arginase combined with or without low concentration of canavanine substantially enhanced cell radioresponse reflected by a loss in spheroid regrowth probability and SCD(50) values reduced by a factor of 1.5-3. Our data strongly suggest that arginine withdrawal alone or in combination with canavanine is a promising antitumor strategy with potential to enhance cancer cure by irradiation.
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24
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McPhail KL, Armstrong DJ, Azevedo MD, Banowetz GM, Mills DI. 4-Formylaminooxyvinylglycine, an herbicidal germination-arrest factor from Pseudomonas rhizosphere bacteria. JOURNAL OF NATURAL PRODUCTS 2010; 73:1853-7. [PMID: 20979386 PMCID: PMC3049220 DOI: 10.1021/np1004856] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
A new oxyvinylglycine has been identified as a naturally occurring herbicide that irreversibly arrests germination of the seeds of grassy weeds, such as annual bluegrass (Poa annua), without significantly affecting the growth of established grass seedlings and mature plants or germination of the seeds of broadleaf plant species (dicots). Previously, Pseudomonas fluorescens WH6 and over 20 other rhizosphere bacteria were isolated and selected for their ability to arrest germination of P. annua seeds. The germination-arrest factor (GAF, 1) responsible for this developmentally specific herbicidal action has now been isolated from the culture filtrate of P. fluorescens WH6. Purification of this highly polar, low molecular weight natural product allowed its structure to be assigned as 4-formylaminooxy-l-vinylglycine on the basis of NMR spectroscopic and mass spectrometric data, in combination with D/L-amino acid oxidase reactions to establish the absolute configuration. Assay results for P. annua inhibition by related compounds known to regulate plant growth are presented, and a cellular target for 1 is proposed. Furthermore, using bioassays, TLC, and capillary NMR spectroscopy, it has been shown that GAF (1) is secreted by all other herbicidally active rhizosphere bacteria in our collection.
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Affiliation(s)
- Kerry L McPhail
- College of Pharmacy, 203 Pharmacy Building, Oregon State University, Corvallis, Oregon 97331, United States.
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25
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Cai T, Cai W, Zhang J, Zheng H, Tsou AM, Xiao L, Zhong Z, Zhu J. Host legume-exuded antimetabolites optimize the symbiotic rhizosphere. Mol Microbiol 2009; 73:507-17. [PMID: 19602148 DOI: 10.1111/j.1365-2958.2009.06790.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Rhizobia form symbiotic nodules on host legumes and fix nitrogen for their hosts in exchange for nutrients. In order to establish this mutually beneficial relationship, rhizobia must compete with other soil bacteria in the host legume rhizosphere to colonize plant roots efficiently. A promoter-trap transposon screen in Mesorhizobium tianshanense, a Rhizobium that forms nodules on licorice (Glycyrrhiza uralensis) plants revealed that the expression of msiA, which encodes a putative exporter protein belonging to the LysE family of translocators, is activated by both legume exudates and MsiR, a LysR family transcriptional regulator. Chemical analysis suggests that the msiA-inducing signal in exudates is canavanine, an anti-metabolite present in the seeds and exudates of a variety of legume plants. We show that MsiA serves as a canavanine exporter that is indispensable for canavanine resistance in M. tianshanense. We also show that the expression of MsiA homologues in other rhizobial species is induced by canavanine and is critical for canavanine resistance. Furthermore, rhizobial canavanine resistance is important for root hair adherence as well as for survival in a canavanine-producing legume rhizosphere. Together, these data suggest that host legumes may exude specific antimetabolites into their surroundings to optimize the bacterial population in order to have successful symbiotic events with rhizobia.
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Affiliation(s)
- Tao Cai
- Department of Microbiology, MOA Key Laboratory of Microbiological Engineering of Agricultural Environment, Nanjing Agricultural University, Nanjing, China
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26
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Stander A, Marais S, Stivaktas V, Vorster C, Albrecht C, Lottering ML, Joubert AM. In vitro effects of Sutherlandia frutescens water extracts on cell numbers, morphology, cell cycle progression and cell death in a tumorigenic and a non-tumorigenic epithelial breast cell line. JOURNAL OF ETHNOPHARMACOLOGY 2009; 124:45-60. [PMID: 19527821 DOI: 10.1016/j.jep.2009.04.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Revised: 04/01/2009] [Accepted: 04/03/2009] [Indexed: 05/27/2023]
Abstract
Sutherlandia frutescens is a South African herb traditionally used for internal cancers, diabetes, a variety of inflammatory conditions and recently to improve the overall health in cancer and HIV/AIDS patients. The in vitro effects of S. frutescens extracts were evaluated on cell numbers, morphology, cell cycle progression and cell death. Dose-dependent studies (2-10 mg/ml) revealed a decrease in malignant cell numbers when compared to their controls. S. frutescens extracts (10 mg/ml) decreased cell growth in a statistically significantly manner to 26% and 49% (P<0.001) in human breast adenocarcinoma (MCF-7) and human non-tumorigenic epithelial mammary gland cells (MCF-12A) respectively after 72 h of exposure. Cell density was significantly compromised and hypercondensed chromatin, cytoplasmic shrinking, membrane blebbing and apoptotic bodies were more pronounced in the MCF-7 cell line. Both S. frutescens-treated cell lines exhibited and increased tendency for acridine orange staining, suggesting increased lysosomal and/or autophagy activity. Flow cytometry showed an increase in the sub G(1) apoptotic fraction and an S phase arrest in both the 5 mg/ml and 10 mg/ml S. frutescens-treated cells. S. frutescens induced an increase in apoptosis in both cell lines as detected by Annexin V and propidium iodide flow cytometric measurement. At 10 mg/ml, late stages of apoptosis were more prominent in MCF-7 S. frutescens-treated cells when compared to the MCF-12A cells. Transmission electron microscopy revealed hallmarks of increased vacuolarization and hypercondensed chromatin, suggesting autophagic and apoptotic processes. The preliminary study demonstrates that S. frutescens water extracts exert a differential action mechanism in non-tumorigenic MCF-12A cells when compared to tumorigenic MCF-7 cells, warranting future studies on this multi-purpose medicinal plant in southern Africa.
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Affiliation(s)
- Andre Stander
- Department of Physiology, PO Box 2034, University of Pretoria, Pretoria 0001, South Africa.
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27
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Fatumo S, Plaimas K, Mallm JP, Schramm G, Adebiyi E, Oswald M, Eils R, König R. Estimating novel potential drug targets of Plasmodium falciparum by analysing the metabolic network of knock-out strains in silico. INFECTION GENETICS AND EVOLUTION 2008; 9:351-8. [PMID: 18313365 DOI: 10.1016/j.meegid.2008.01.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Revised: 12/21/2007] [Accepted: 01/17/2008] [Indexed: 10/22/2022]
Abstract
Malaria is one of the world's most common and serious diseases causing death of about 3 million people each year. Its most severe occurrence is caused by the protozoan Plasmodium falciparum. Biomedical research could enable treating the disease by effectively and specifically targeting essential enzymes of this parasite. However, the parasite has developed resistance to existing drugs making it indispensable to discover new drugs. We have established a simple computational tool which analyses the topology of the metabolic network of P. falciparum to identify essential enzymes as possible drug targets. We investigated the essentiality of a reaction in the metabolic network by deleting (knocking-out) such a reaction in silico. The algorithm selected neighbouring compounds of the investigated reaction that had to be produced by alternative biochemical pathways. Using breadth first searches, we tested qualitatively if these products could be generated by reactions that serve as potential deviations of the metabolic flux. With this we identified 70 essential reactions. Our results were compared with a comprehensive list of 38 targets of approved malaria drugs. When combining our approach with an in silico analysis performed recently [Yeh, I., Hanekamp, T., Tsoka, S., Karp, P.D., Altman, R.B., 2004. Computational analysis of Plasmodium falciparum metabolism: organizing genomic information to facilitate drug discovery. Genome Res. 14, 917-924] we could improve the precision of the prediction results. Finally we present a refined list of 22 new potential candidate targets for P. falciparum, half of which have reasonable evidence to be valid targets against micro-organisms and cancer.
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Affiliation(s)
- Segun Fatumo
- Computer and Information Sciences Department, Covenant University, Ota, Nigeria
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Bell EA, Watson AA, Nash RJ. Non-Protein Amino Acids: A Review of the Biosynthesis and Taxonomic Significance. Nat Prod Commun 2008. [DOI: 10.1177/1934578x0800300117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The non-protein amino acids, with which we are concerned here, are not incorporated into the proteins of the organisms that synthesize them nor are their residues formed by the post-translational modification of protein amino acid residues. Non-protein amino acids are of value in the study of relationships between species and higher taxa of organisms because most of them are of restricted distribution. If a particular non-protein amino acid is only known to occur in a limited group of species which are related in other respects then it is probable that these species have all arisen from a common ancestral form in which the biosynthetic pathway to that particular non-protein amino acid already existed.
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Affiliation(s)
- E. Arthur Bell
- Formerly at the Department of Biochemistry, King's College, University of London, The Strand, London, UK
| | - Alison A. Watson
- Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion, SY23 3EB, UK
| | - Robert J. Nash
- Summit (Wales) Limited, Plas Gogerddan, Aberystwyth, Ceredigion SY 23 3EB, UK
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Abstract
Quorum sensing is widely recognized as an efficient mechanism to regulate expression of specific genes responsible for communal behavior in bacteria. Several bacterial phenotypes essential for the successful establishment of symbiotic, pathogenic, or commensal relationships with eukaryotic hosts, including motility, exopolysaccharide production, biofilm formation, and toxin production, are often regulated by quorum sensing. Interestingly, eukaryotes produce quorum-sensing-interfering (QSI) compounds that have a positive or negative influence on the bacterial signaling network. This eukaryotic interference could result in further fine-tuning of bacterial quorum sensing. Furthermore, recent work involving the synthesis of structural homologs to the various quorum-sensing signal molecules has resulted in the development of additional QSI compounds that could be used to control pathogenic bacteria. The creation of transgenic plants that express bacterial quorum-sensing genes is yet another strategy to interfere with bacterial behavior. Further investigation on the manipulation of quorum-sensing systems could provide us with powerful tools against harmful bacteria.
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Affiliation(s)
- Juan E González
- Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, TX 75083-0688, USA.
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Andriole EJ, Colyer KE, Cornell E, Poutsma JC. Proton Affinity of Canavanine and Canaline, Oxyanalogues of Arginine and Ornithine, from the Extended Kinetic Method. J Phys Chem A 2006; 110:11501-8. [PMID: 17020263 DOI: 10.1021/jp063081f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The absolute proton affinities of the nonprotein amino acids canavanine and canaline have been determined using the extended kinetic method in an electrospray ionization quadrupole ion trap instrument. Canavanine results from the substitution of an oxygen atom for the delta-CH2 group in the side chain of the protein amino acid arginine, whereas canaline results from a similar substitution at the delta-CH2 group in the side chain of ornithine. Absolute proton affinities of 1001+/-9 and 950+/-7 kJ/mol are obtained for canavanine and canaline, respectively. For canaline, this proton affinity is in excellent agreement with theoretical predictions obtained using the hybrid density functional theory method B3LYP/6-311++G**//B3LYP/6-31+G*. For canavanine, theory predicts a somewhat larger proton affinity of 1015 kJ/mol. Oxygen atom substitution in these nonprotein amino acids results in a decrease in their proton affinities of 40-50 kJ/mol compared to arginine and ornithine.
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Affiliation(s)
- Erica J Andriole
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
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Conn KJ, Gao W, McKee A, Lan MS, Ullman MD, Eisenhauer PB, Fine RE, Wells JM. Identification of the protein disulfide isomerase family member PDIp in experimental Parkinson's disease and Lewy body pathology. Brain Res 2006; 1022:164-72. [PMID: 15353226 DOI: 10.1016/j.brainres.2004.07.026] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2004] [Indexed: 11/15/2022]
Abstract
Parkinson's disease (PD) is a slowly progressing neurodegenerative disorder with no clear etiology. Pathological hallmarks of the disease include the loss of dopaminergic neurons from the substantia nigra (SN) and the presence of Lewy bodies (LBs) (alpha-synuclein and ubiquitin-positive, eosinophilic, cytoplasmic inclusions) in many of the surviving neurons. Experimental modeling of PD neurodegeneration using the neurotoxins 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 1-methyl-4-phenyl-pyridinium (MPP(+)) has identified changes in gene expression of different endoplasmic reticulum (ER) stress proteins associated with MPTP- and PD-related neurodegeneration. We show that the protein disulfide isomerase (PDI) family member pancreatic protein disulfide isomerase (PDIp), previously considered exclusively expressed in pancreatic tissue, is uniquely upregulated among PDI family members within 24 h following exposure of retinoic acid (RA)-differentiated SH-SY5Y human neuroblastoma cells to either 1 mM MPP(+) or 10 microM of the highly specific proteasome inhibitor lactacystin. RT-PCR confirms PDIp expression in brain of post-mortem human PD subjects and immunohistochemical studies demonstrate PDIp immunoreactivity in LBs. Collectively, these findings suggest that increased PDIp expression in dopaminergic (DA) neurons might contribute to LB formation and neurodegeneration, and that this increased PDIp expression may be the result of proteasome impairment.
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Affiliation(s)
- Kelly J Conn
- Department of Veterans Affairs, VA Medical Center, 200 Springs Road, Building 17, Bedford, MA 01730, USA.
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Keshavan ND, Chowdhary PK, Haines DC, González JE. L-Canavanine made by Medicago sativa interferes with quorum sensing in Sinorhizobium meliloti. J Bacteriol 2006; 187:8427-36. [PMID: 16321947 PMCID: PMC1317012 DOI: 10.1128/jb.187.24.8427-8436.2005] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sinorhizobium meliloti is a gram-negative soil bacterium, capable of establishing a nitrogen-fixing symbiosis with its legume host, alfalfa (Medicago sativa). Quorum sensing plays a crucial role in this symbiosis, where it influences the nodulation process and the synthesis of the symbiotically important exopolysaccharide II (EPS II). S. meliloti has three quorum-sensing systems (Sin, Tra, and Mel) that use N-acyl homoserine lactones as their quorum-sensing signal molecule. Increasing evidence indicates that certain eukaryotic hosts involved in symbiotic or pathogenic relationships with gram-negative bacteria produce quorum-sensing-interfering (QSI) compounds that can cross-communicate with the bacterial quorum-sensing system. Our studies of alfalfa seed exudates suggested the presence of multiple signal molecules capable of interfering with quorum-sensing-regulated gene expression in different bacterial strains. In this work, we choose one of these QSI molecules (SWI) for further characterization. SWI inhibited violacein production, a phenotype that is regulated by quorum sensing in Chromobacterium violaceum. In addition, this signal molecule also inhibits the expression of the S. meliloti exp genes, responsible for the production of EPS II, a quorum-sensing-regulated phenotype. We identified this molecule as l-canavanine, an arginine analog, produced in large quantities by alfalfa and other legumes.
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Affiliation(s)
- Neela D Keshavan
- Department of Molecular and Cell Biology, University of Texas at Dallas, FO 3.1, Richardson, TX 75083-0688, USA
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Olalde Rangel JA, Magarici M, Amendola F, del Castillo O. The Systemic Theory of Living Systems. Part IV: Systemic Medicine--The Praxis. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2005; 2:429-39. [PMID: 16322799 PMCID: PMC1297512 DOI: 10.1093/ecam/neh139] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Accepted: 10/03/2005] [Indexed: 12/31/2022]
Abstract
This fourth lecture illustrates the praxis and results of Systemic Medicine (SM) in various therapeutic applications. SM's success has made it popular throughout Venezuela and Puerto Rico. The treatment of over 300,000 patients by 150 orthodox MD's, trained and qualified in SM, in 35 medical establishments with above average results corroborate its effectiveness as an eCAM in chronic degenerative diseases. Herein we provide a synopsis of results obtained in four such pathologies-the journal's necessary space restrictions somewhat limiting content-as well as clinical and photographic evidence. The validity of any medical theory is substantiated by its degree of effectivity and success. The workability of evidence-based SM corroborates Systemic Theory's transcendence.
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Affiliation(s)
- José A Olalde Rangel
- Adaptogenic Medical Centers, Calle del Arenal c/c Luis de Camoes, La Trinidad, Caracas 1080, Venezuela.
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