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Banerjee S, Bright SA, Smith JA, Burgeat J, Martinez-Calvo M, Williams DC, Kelly JM, Gunnlaugsson T. Supramolecular Approach to Enantioselective DNA Recognition Using Enantiomerically Resolved Cationic 4-Amino-1,8-naphthalimide-Based Tröger’s Bases. J Org Chem 2014; 79:9272-83. [DOI: 10.1021/jo501711g] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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102
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Kleemann DO, Kelly JM, Arney LJ, Farley IL, Tilbrook AJ, Walker SK. Positive Effects of Melatonin Treatment on the Reproductive Performance of Young Border Leicester Rams Mated to Merino Ewes in Spring: Preliminary Observations. Reprod Domest Anim 2014; 49:894-8. [DOI: 10.1111/rda.12387] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 06/22/2014] [Indexed: 11/29/2022]
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103
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Kelly JM, Callum JL, Rizoli SB. 1:1:1 - Warranted or wasteful? Even where appropriate, high ratio transfusion protocols are costly: early transition to individualized care benefits patients and transfusion services. Expert Rev Hematol 2014; 6:631-3. [PMID: 24219547 DOI: 10.1586/17474086.2013.859520] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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104
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Gilbert A, Kelly JM, Budzwait M, Von Gustorf EK. The Comparative Photochemical Behaviour of Dibenzenechromium and Benzenetricarbonyl Chromium. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/znb-1976-0819] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In comparison with (C6H6)Cr(CO)3, (C6H6)2Cr is relatively light stable. The major part of the light energy absorbed by (C6H6)2Cr leads neither to its decomposition or ligand exchange, nor can it be transferred to common low energy triplet acceptors. Internal dissipation of energy, either by rapid conversion to the ground state or by rapid reversible isomerization, must be an important process.
In the case of (C6H6)Cr(CO)3, the main pathway to the previously reported lightinduced exchange of benzene involves an intermediate which is suggested to be (benzene)-dicarbonylchromium (1) and not a one-step dissociation of the excited molecule, to give Cr(CO)3 and benzene1b: 1 is also of major importance for the exchange of CO.
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Lewis MD, Fortes Francisco A, Taylor MC, Burrell-Saward H, McLatchie AP, Miles MA, Kelly JM. Bioluminescence imaging of chronic Trypanosoma cruzi infections reveals tissue-specific parasite dynamics and heart disease in the absence of locally persistent infection. Cell Microbiol 2014; 16:1285-300. [PMID: 24712539 PMCID: PMC4190689 DOI: 10.1111/cmi.12297] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 03/18/2014] [Indexed: 12/12/2022]
Abstract
Summary Chronic Trypanosoma cruzi infections lead to cardiomyopathy in 20–30% of cases. A causal link between cardiac infection and pathology has been difficult to establish because of a lack of robust methods to detect scarce, focally distributed parasites within tissues. We developed a highly sensitive bioluminescence imaging system based on T. cruzi expressing a novel luciferase that emits tissue-penetrating orange-red light. This enabled long-term serial evaluation of parasite burdens in individual mice with an in vivo limit of detection of significantly less than 1000 parasites. Parasite distributions during chronic infections were highly focal and spatiotemporally dynamic, but did not localize to the heart. End-point ex vivo bioluminescence imaging allowed tissue-specific quantification of parasite loads with minimal sampling bias. During chronic infections, the gastro-intestinal tract, specifically the colon and stomach, was the only site where T. cruzi infection was consistently observed. Quantitative PCR-inferred parasite loads correlated with ex vivo bioluminescence and confirmed the gut as the parasite reservoir. Chronically infected mice developed myocarditis and cardiac fibrosis, despite the absence of locally persistent parasites. These data identify the gut as a permissive niche for long-term T. cruzi infection and show that canonical features of Chagas disease can occur without continual myocardium-specific infection.
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Taylor MC, Kelly JM. Optimizing bioluminescence imaging to study protozoan parasite infections. Trends Parasitol 2014; 30:161-2. [PMID: 24485045 DOI: 10.1016/j.pt.2014.01.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 01/15/2014] [Accepted: 01/15/2014] [Indexed: 11/28/2022]
Abstract
Bioluminescence imaging is a non-invasive technique which can be used to monitor infections in real-time. However, its utility is restricted by difficulties in detecting pathogens in deep tissue. 'Red-shifted' luciferases, which emit light of longer wavelength than standard bioluminescence-generating proteins, greatly enhance sensitivity, and have wide applicability for studying parasite infections.
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Campos MCO, Leon LL, Taylor MC, Kelly JM. Benznidazole-resistance in Trypanosoma cruzi: evidence that distinct mechanisms can act in concert. Mol Biochem Parasitol 2014; 193:17-9. [PMID: 24462750 PMCID: PMC3988956 DOI: 10.1016/j.molbiopara.2014.01.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 01/10/2014] [Accepted: 01/13/2014] [Indexed: 11/27/2022]
Abstract
Drug-resistance in T. cruzi can arise independently within a single population. Distinct mechanisms can contribute to benznidazole-resistance in T. cruzi. Stop-codon generating mutations in the TcNTR gene linked to benznidazole-resistance.
Benznidazole is the main drug used to treat Trypanosoma cruzi infections. However, frequent instances of treatment failure have been reported. To better understand potential resistance mechanisms, we analysed three clones isolated from a single parasite population that had undergone benznidazole-selection. These clones exhibited differing levels of benznidazole-resistance (varying between 9 and 26-fold), and displayed cross-resistance to nifurtimox (2 to 4-fold). Each clone had acquired a stop-codon-generating mutation in the gene which encodes the nitroreductase (TcNTR) that is responsible for activating nitroheterocyclic pro-drugs. In addition, one clone had lost a copy of the chromosome containing TcNTR. However, these processes alone are insufficient to account for the extent and diversity of benznidazole-resistance. It is implicit from our results that additional mechanisms must also operate and that T. cruzi has an intrinsic ability to develop drug-resistance by independent sequential steps, even within a single population. This has important implications for drug development strategies.
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108
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Zhang Y, Charles DE, Ledwith DM, Aherne D, Cunningham S, Voisin M, Blau WJ, Gun'ko YK, Kelly JM, Brennan-Fournet ME. Wash-free highly sensitive detection of C-reactive protein using gold derivatised triangular silver nanoplates. RSC Adv 2014. [DOI: 10.1039/c4ra04958f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Rapid, wash-free highly sensitive detection of C-reactive protein is reported using nanoplate biosensor sols.
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109
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Devereux SJ, Keane PM, Vasudevan S, Sazanovich IV, Towrie M, Cao Q, Sun XZ, George MW, Cardin CJ, Kane-Maguire NAP, Kelly JM, Quinn SJ. Study of picosecond processes of an intercalated dipyridophenazine Cr(iii) complex bound to defined sequence DNAs using transient absorption and time-resolved infrared methods. Dalton Trans 2014; 43:17606-9. [DOI: 10.1039/c4dt01989j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Excited-state quenching of DNA intercalated [Cr(phen)2(dppz)]3+ by guanine proceeds by rapid forward and back electron transfer of <3 ps.
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Keane PM, Wojdyla M, Doorley GW, Kelly JM, Parker AW, Clark IP, Greetham GM, Towrie M, Magno LM, Quinn SJ. Long-lived excited states in i-motif DNA studied by picosecond time-resolved IR spectroscopy. Chem Commun (Camb) 2014; 50:2990-2. [DOI: 10.1039/c3cc46594b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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111
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McLatchie AP, Burrell-Saward H, Myburgh E, Lewis MD, Ward TH, Mottram JC, Croft SL, Kelly JM, Taylor MC. Highly sensitive in vivo imaging of Trypanosoma brucei expressing "red-shifted" luciferase. PLoS Negl Trop Dis 2013; 7:e2571. [PMID: 24278497 PMCID: PMC3836995 DOI: 10.1371/journal.pntd.0002571] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 10/21/2013] [Indexed: 11/30/2022] Open
Abstract
Background Human African trypanosomiasis is caused by infection with parasites of the Trypanosoma brucei species complex, and threatens over 70 million people in sub-Saharan Africa. Development of new drugs is hampered by the limitations of current rodent models, particularly for stage II infections, which occur once parasites have accessed the CNS. Bioluminescence imaging of pathogens expressing firefly luciferase (emission maximum 562 nm) has been adopted in a number of in vivo models of disease to monitor dissemination, drug-treatment and the role of immune responses. However, lack of sensitivity in detecting deep tissue bioluminescence at wavelengths below 600 nm has restricted the wide-spread use of in vivo imaging to investigate infections with T. brucei and other trypanosomatids. Methodology/Principal findings Here, we report a system that allows the detection of fewer than 100 bioluminescent T. brucei parasites in a murine model. As a reporter, we used a codon-optimised red-shifted Photinus pyralis luciferase (PpyRE9H) with a peak emission of 617 nm. Maximal expression was obtained following targeted integration of the gene, flanked by an upstream 5′-variant surface glycoprotein untranslated region (UTR) and a downstream 3′-tubulin UTR, into a T. brucei ribosomal DNA locus. Expression was stable in the absence of selective drug for at least 3 months and was not associated with detectable phenotypic changes. Parasite dissemination and drug efficacy could be monitored in real time, and brain infections were readily detectable. The level of sensitivity in vivo was significantly greater than achievable with a yellow firefly luciferase reporter. Conclusions/Significance The optimised bioluminescent reporter line described here will significantly enhance the application of in vivo imaging to study stage II African trypanosomiasis in murine models. The greatly increased sensitivity provides a new framework for investigating host-parasite relationships, particularly in the context of CNS infections. It should be ideally suited to drug evaluation programmes. Parasites of the Trypanosoma brucei species complex are the causative agents of human African trypanosomiasis. There is an urgent need for new drugs to treat this debilitating and potentially fatal infection, especially in its late stage, when parasites have entered the central nervous system. Factors which hamper drug development include the limitations of the current murine models for stage II disease. In vivo bioluminescence imaging is a non-invasive technique that can be used to monitor infections in real time and is a powerful new approach for studying drug effectiveness. However, application of this imaging technology to trypanosome infections has been restricted because of lack of sensitivity. In this paper, we have taken a major step to resolve this problem. The enhanced sensitivity in infected mice is based on the high level expression in trypanosomes of a “red-shifted” luciferase variant that greatly improves bioluminescence detection in deep tissue. The system which we have developed should be a widely applicable tool for providing new insights into the infection biology of T. brucei.
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Cardin CJ, Hall JP, Kelly JM, Poynton F, Gunnlaugsson T, Quinn SJ. Towards biophotocrystallography with photooxidisable ruthenium polypyridyl complexes. Acta Crystallogr A 2013. [DOI: 10.1107/s0108767313094841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
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113
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Hall JP, O'Sullivan K, Niyazi H, Winter G, Sorensen T, Cardin D, Kelly JM, Cardin CJ. Ruthenium complexes bind to DNA with sequence specificity and directional preference. Acta Crystallogr A 2013. [DOI: 10.1107/s0108767313097109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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114
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Hall JP, Cook D, Morte SR, McIntyre P, Buchner K, Beer H, Cardin DJ, Brazier JA, Winter G, Kelly JM, Cardin CJ. X-ray crystal structure of rac-[Ru(phen)2dppz]2+ with d(ATGCAT)2 shows enantiomer orientations and water ordering. J Am Chem Soc 2013; 135:12652-9. [PMID: 23875832 DOI: 10.1021/ja403590e] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We report an atomic resolution X-ray crystal structure containing both enantiomers of rac-[Ru(phen)2dppz](2+) with the d(ATGCAT)2 DNA duplex (phen = phenanthroline; dppz = dipyridophenazine). The first example of any enantiomeric pair crystallized with a DNA duplex shows different orientations of the Λ and Δ binding sites, separated by a clearly defined structured water monolayer. Job plots show that the same species is present in solution. Each enantiomer is bound at a TG/CA step and shows intercalation from the minor groove. One water molecule is directly located on one phenazine N atom in the Δ-enantiomer only.
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Taylor MC, McLatchie AP, Kelly JM. Evidence that transport of iron from the lysosome to the cytosol in African trypanosomes is mediated by a mucolipin orthologue. Mol Microbiol 2013; 89:420-32. [PMID: 23750752 PMCID: PMC3828870 DOI: 10.1111/mmi.12285] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2013] [Indexed: 11/28/2022]
Abstract
Bloodstream-form Trypanosoma brucei acquire iron by receptor-mediated endocytosis of host transferrin. However, the mechanism(s) by which iron is then transferred from the lysosome to the cytosol are unresolved. Here, we provide evidence for the involvement of a protein (TbMLP) orthologous to the mammalian endolysosomal cation channel Mucolipin 1. In T. brucei, we show that this protein is localized to the single parasite lysosome. TbMLP null mutants could only be generated in the presence of an expressed ectopic copy, suggesting that the protein is essential. RNAi-mediated ablation resulted in a growth defect in vitro and led to a sevenfold increase in susceptibility to the iron-chelators deferoxamine and salicylhydroxamic acid. Conditional null mutants remained viable when the ectopic copy was repressed, but were hypersensitive to deferoxamine and displayed a growth defect similar to that observed following RNAi. The conditional nulls also retained virulence in vivo in the absence of the doxycycline inducer. These data provide strong evidence that TbMLP has a role in import of iron into the cytosol of African trypanosomes. They also indicate that even when expression is greatly reduced, there is sufficient protein, or an alternative mechanism, to provide the parasite with an adequate supply of cytosolic iron.
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Gallagher SA, Comby S, Wojdyla M, Gunnlaugsson T, Kelly JM, Gun’ko YK, Clark IP, Greetham GM, Towrie M, Quinn SJ. Efficient Quenching of TGA-Capped CdTe Quantum Dot Emission by a Surface-Coordinated Europium(III) Cyclen Complex. Inorg Chem 2013; 52:4133-5. [DOI: 10.1021/ic3027623] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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117
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Banerjee S, Veale EB, Phelan CM, Murphy SA, Tocci GM, Gillespie LJ, Frimannsson DO, Kelly JM, Gunnlaugsson T. Recent advances in the development of 1,8-naphthalimide based DNA targeting binders, anticancer and fluorescent cellular imaging agents. Chem Soc Rev 2013; 42:1601-18. [DOI: 10.1039/c2cs35467e] [Citation(s) in RCA: 492] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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118
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Banerjee S, Kitchen JA, Gunnlaugsson T, Kelly JM. The effect of the 4-amino functionality on the photophysical and DNA binding properties of alkyl-pyridinium derived 1,8-naphthalimides. Org Biomol Chem 2013; 11:5642-55. [DOI: 10.1039/c3ob40370j] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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119
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Koperniku A, Papanastasiou I, Foscolos GB, Tsotinis A, Taylor MC, Kelly JM. Synthesis and trypanocidal action of new adamantane substituted imidazolines. MEDCHEMCOMM 2013. [DOI: 10.1039/c3md00081h] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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120
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Banerjee S, Kitchen JA, Bright SA, O'Brien JE, Williams DC, Kelly JM, Gunnlaugsson T. Synthesis, spectroscopic and biological studies of a fluorescent Pt(ii) (terpy) based 1,8-naphthalimide conjugate as a DNA targeting agent. Chem Commun (Camb) 2013; 49:8522-4. [DOI: 10.1039/c3cc44962a] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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121
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Niyazi H, Hall JP, O'Sullivan K, Winter G, Sorensen T, Kelly JM, Cardin CJ. Crystal structures of Λ-[Ru(phen)₂dppz]²⁺ with oligonucleotides containing TA/TA and AT/AT steps show two intercalation modes. Nat Chem 2012; 4:621-8. [PMID: 22824893 DOI: 10.1038/nchem.1397] [Citation(s) in RCA: 168] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 05/30/2012] [Indexed: 12/22/2022]
Abstract
The ruthenium complex [Ru(phen)(2)(dppz)](2+) (where phen is phenanthroline and dppz dipyridophenazine is known as a 'light switch' complex because its luminescence in solution is significantly enhanced in the presence of DNA. This property is poised to serve in diagnostic and therapeutic applications, but its binding mode with DNA needs to be elucidated further. Here, we describe the crystal structures of the Λ enantiomer bound to two oligonucleotide duplexes. The dppz ligand intercalates symmetrically and perpendicularly from the minor groove of the d(CCGGTACCGG)(2) duplex at the central TA/TA step, but not at the central AT/AT step of d(CCGGATCCGG)(2). In both structures, however, a second ruthenium complex links the duplexes through the combination of a shallower angled intercalation into the C(1)C(2)/G(9)G(10) step at the end of the duplex, and semi-intercalation into the G(3)G(4) step of an adjacent duplex. The TA/TA specificity of the perpendicular intercalation arises from the packing of phenanthroline ligands against the adenosine residue.
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Mejia AM, Hall BS, Taylor MC, Gómez-Palacio A, Wilkinson SR, Triana-Chávez O, Kelly JM. Benznidazole-resistance in Trypanosoma cruzi is a readily acquired trait that can arise independently in a single population. J Infect Dis 2012; 206:220-8. [PMID: 22551809 PMCID: PMC3379838 DOI: 10.1093/infdis/jis331] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Benznidazole is the frontline drug used against Trypanosoma cruzi, the causative agent of Chagas disease. However, treatment failures are often reported. Here, we demonstrate that independently acquired mutations in the gene encoding a mitochondrial nitroreductase (TcNTR) can give rise to distinct drug-resistant clones within a single population. Following selection of benznidazole-resistant parasites, all clones examined had lost one of the chromosomes containing the TcNTR gene. Sequence analysis of the remaining TcNTR allele revealed 3 distinct mutant genes in different resistant clones. Expression studies showed that these mutant proteins were unable to activate benznidazole. This correlated with loss of flavin mononucleotide binding. The drug-resistant phenotype could be reversed by transfection with wild-type TcNTR. These results identify TcNTR as a central player in acquired resistance to benznidazole. They also demonstrate that T. cruzi has a propensity to undergo genetic changes that can lead to drug resistance, a finding that has implications for future therapeutic strategies.
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123
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Banerjee S, Kitchen JA, Gunnlaugsson T, Kelly JM. Synthesis and photophysical evaluation of a pyridinium 4-amino-1,8-naphthalimide derivative that upon intercalation displays preference for AT-rich double-stranded DNA. Org Biomol Chem 2012; 10:3033-43. [PMID: 22395853 DOI: 10.1039/c2ob06898b] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis, characterisation and solid state crystal structure of a cationic 4-amino-1,8-naphthalimide derivative (1) are described. The photophysical properties of 1 are shown to vary with the solvent polarity and H-bonding ability. The fluorescence of 1 is enhanced and blue-shifted in its 1:1 complex with 5'-adenosine-monophosphate while it is partially quenched and red-shifted in its complex with 5'-guanosine-monophosphate. Linear and circular dichroism measurements show that 1 binds to double-stranded DNA by intercalation. Comparative UV-visible and fluorescence studies with double stranded synthetic polynucleotides poly(dA-dT)(2) and poly(dG-dC)(2) show that 1 binds much more strongly to the AT polymer; 1 also has a strong preference for A-T rich sequences in natural DNA. Thermal denaturation measurements also reveal a much greater stabilisation of the double-stranded poly(dA-dT)(2) than of natural DNA.
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Kelly JM, Taylor MC, Horn D, Loza E, Kalvinsh I, Björkling F. Inhibitors of human histone deacetylase with potent activity against the African trypanosome Trypanosoma brucei. Bioorg Med Chem Lett 2012; 22:1886-90. [PMID: 22326398 PMCID: PMC3314994 DOI: 10.1016/j.bmcl.2012.01.072] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 01/17/2012] [Accepted: 01/20/2012] [Indexed: 11/21/2022]
Abstract
A number of hydroxamic acid derivatives which inhibit human histone deacetylases were investigated for efficacy against cultured bloodstream form Trypanosoma brucei. Three out of the four classes tested displayed significant activity. The majority of compounds blocked parasite growth in the submicromolar range. The most potent was a member of the sulphonepiperazine series with an IC(50) of 34nM. These results identify lead compounds with potential for the development of a novel class of trypanocidal agent.
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Keane PM, Wojdyla M, Doorley GW, Kelly JM, Clark IP, Parker AW, Greetham GM, Towrie M, Magno LM, Quinn SJ. Ultrafast IR spectroscopy of polymeric cytosine nucleic acids reveal the long-lived species is due to a localised state. Phys Chem Chem Phys 2012; 14:6307-11. [PMID: 22358255 DOI: 10.1039/c2cp23774a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The decay pathways of UV-excited cytosine polymers are investigated using picosecond time-resolved infrared spectroscopy. Similar yields of a non-emissive (1)nπ* state are found in the single-stranded dC(30) polymer as in the dCMP monomer, but with a longer lifetime in the polymer (80 ps vs. 39 ps). A longer lifetime is also found in the d(CpC) dinucleotide. No evidence of excimer states is observed, suggesting that localised (1)nπ* excited states are the most significant intermediates present on the picosecond timescale.
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