FATTY ACID METABOLISM IN APICOMPLEXAN PARASITES

Plasmodium falciparum and Toxoplasma gondii are human parasites that belong to the phylum Apicomplexa and are the causative agents of malaria and toxoplasmosis, respectively. These parasites infect billions of people annually worldwide causing significant morbidity. We made use of biochemical and biophysical methods to better understand essential fatty acid metabolism of these pathogens, such as Fatty Acid Synthesis type II (FAS-II) and lipoate metabolism. The apicoplast, a plastid organelle, harbors the machinery for FAS-II which is essential for the survival of T. gondii and for liver stage malaria parasites. A small biocide, triclosan, is known to target the last enzyme in FAS-II with high specificity. Several modifications were made to this scaffold molecule to increase its druggability properties, while retaining specificity. We designed a method to measure the inhibition and IC50 values of triclosan analogues in 96-well plate format. Also, we modified a thermal shift assay to measure their binding affinity to the enzyme and determine their inhibition mode of action. The FAS-II produces octanoyl-ACP, which is the substrate of downstream enzymes to synthesize lipoate on pyruvate dehydrogenase (PDH). Contrary to the apicoplast, the mitochondrion relies on lipoate scavenged from the host which is essential for the survival of these parasites. In both parasites, two lipoate ligases are localized to the mitochondrion, LipL1 and LipL2. These ligases are believed to catalyze the attachment of lipoate to three lipoate-requiring substrates in the mitochondrion: the H-protein, the branch chain amino acid dehydrogenase (BCDH) and the α-ketoglutarate dehydrogenase (KDH). We show that LipL1 is the sole lipoate ligase in the mitochondrion with specificity for the H-protein. The BCDH and KDH are lipoylated through a concerted mechanism: LipL1 produces the conjugate lipoyl-AMP which is transferred to LipL2 to lipoylate the BCDH and KDH. LipL2 is unable to produce the lipoyl-AMP conjugate, but instead acts as a lipoyl-AMP:N-lysine lipoyltransferase. The two step LipL1+LipL2 lipoylation mechanism appears to be conserved in most apicomplexan parasites, since the genes encoding both enzymes are conserved. Furthermore, lipoate scavenging shows redox sensitivity for the lipoate redox state -a phenomenon that has not been previously described-. Last, we can target the mitochondrial proteins with lipoate analogues and inhibit their activities, causing cell growth inhibition. The lipoylation mechanism found in apicomplexan parasites differs from that found in metazoans, making it an attractive drug target

Crystal structure of lipoate‐bound lipoate ligase 1, LipL1, from Plasmodium falciparum

Plasmodium falciparum lipoate protein ligase 1 (PfLipL1) is an ATP‐dependent ligase that belongs to the biotin/lipoate A/B protein ligase family (PFAM PF03099). PfLipL1 is the only known canonical lipoate ligase in Pf and functions as a redox switch between two lipoylation routes in the parasite mitochondrion. Here, we report the crystal structure of a deletion construct of PfLipL1 (PfLipL1Δ243‐279) bound to lipoate, and validate the lipoylation activity of this construct in both an in vitro lipoylation assay and a cell‐based lipoylation assay. This characterization represents the first step in understanding the redox dependence of the lipoylation mechanism in malaria parasites. Proteins 2017; 85:1777–1783. © 2017 Wiley Periodicals, Inc.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138350/1/prot25324_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138350/2/prot25324-sup-0001-suppinfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138350/3/prot25324.pd

Quality of care in acute coronary syndromes: a critical path implementation

Antecedentes En los últimos años se han realizado avances importantes en el manejo del síndrome coronario agudo, lo cual se ha traducido en una disminución de la mortalidad en este grupo de pacientes. Objetivo Describir los resultados de la implementación de una ruta crítica para el manejo de los síndromes coronarios agudos en el Servicio de Urgencias del Hospital San José de Bogotá, entre el 1 de marzo de 2012 y el 28 de febrero de 2013. Métodos Se realizó un estudio observacional descriptivo prospectivo. La ruta crítica fue estructurada mediante el consenso de los servicios de Medicina Interna, Urgencias y Cardiología, para ser aplicada en las primeras 24 horas del tratamiento del paciente con síndrome coronario agudo definitivo. Resultados Se reclutaron 156 pacientes, de los cuales 25 correspondieron a síndrome coronario agudo con elevación del ST y 131 a síndrome sin elevación del ST. De los síndromes coronarios agudos con elevación del ST el 96% fue sometido a alguna estrategia de reperfusión; 2 (9,5%) pacientes fallecieron. En cuanto al síndrome coronario agudo sin elevación del ST, 33 (25,1%) pacientes presentaron infarto, 98 (74,9%) angina inestable, y 4 (3,2%) fallecieron. El uso de aspirina, betabloqueador, estatina e inhibidor de la enzima convertidora de angiotensina o antagonistas de los receptores de angiotensina II durante las primeras 24 horas fue superior al 90% en toda la muestra. Conclusiones Se alcanzó un nivel superior de cumplimiento de las medidas de desempeño de la atención de los síndromes coronarios agudos después de la implementación de una ruta crítica.Background In recent years there have been important advances in acute coronary syndrome (ACS) management, which translates into a drop in mortality in this group of patients. Objective To describe the results of the implementation of a critical path for the management of ACS, at the emergency service of the Hospital San José in Bogotá, between March 1st, 2012 and February 28th, 2013. Methods A prospective descriptive observational study was carried out. The critical pathway was structured upon consensus among the services of internal medicine, emergency, and cardiology. This pathway was structured to be applied within the first 24hours of the patient's treatment with the final ACS. Results 156 patients were selected, 25 had ST segment elevation ACS and 131 had ACS non-ST segment elevation. 96% of ST segment elevation ACS underwent some reperfusion strategy, 2 (9.5%) patients died. As far as non-ST segment elevation ACS patients are concerned, 33 (25.1%) patients exhibited infarction and 98 (74.9%) unstable angina, with a mortality of 4 (3.2%) patients. The use of aspirin, betablockers, statin, and ACEI or ARA II during the first 24hours was above 90% in the totality of the sample. Conclusions It is demonstrated that a higher level of fulfillment is achieved for the performance measures for ACS care upon a critical pathway implementation

Development of a triclosan scaffold which allows for adaptations on both the A- and B-ring for transport peptides

The enoyl acyl-carrier protein reductase (ENR) enzyme is harbored within the apicoplast of apicomplexan parasites providing a significant challenge for drug delivery, which may be overcome through the addition of transductive peptides, which facilitates crossing the apicoplast membranes. The binding site of triclosan, a potent ENR inhibitor, is occluded from the solvent making the attachment of these linkers challenging. Herein, we have produced 3 new triclosan analogs with bulky A- and B-ring motifs, which protrude into the solvent allowing for the future attachment of molecular transporters for delivery

Cover Image, Volume 85, Issue 9

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138339/1/prot25363.pd

Calidad de la atención de los síndromes coronarios agudos: implementación de una ruta crítica

Antecedentes: En los últimos años se han realizado avances importantes en el manejo del síndrome coronario agudo, lo cual se ha traducido en una disminución de la mortalidad en este grupo de pacientes. Objetivo: Describir los resultados de la implementación de una ruta crítica para el manejo de los síndromes coronarios agudos en el Servicio de Urgencias del Hospital San José de Bogotá, entre el 1 de marzo de 2012 y el 28 de febrero de 2013. Métodos: Se realizó un estudio observacional descriptivo prospectivo. La ruta crítica fue estructurada mediante el consenso de los servicios de Medicina Interna, Urgencias y Cardiología, para ser aplicada en las primeras 24 horas del tratamiento del paciente con síndrome coronario agudo definitivo. Resultados: Se reclutaron 156 pacientes, de los cuales 25 correspondieron a síndrome coronario agudo con elevación del ST y 131 a síndrome sin elevación del ST. De los síndromes coronarios agudos con elevación del ST el 96% fue sometido a alguna estrategia de reperfusión; 2 (9,5%) pacientes fallecieron. En cuanto al síndrome coronario agudo sin elevación del ST, 33 (25,1%) pacientes presentaron infarto, 98 (74,9%) angina inestable, y 4 (3,2%) fallecieron. El uso de aspirina, betabloqueador, estatina e inhibidor de la enzima convertidora de angiotensina o antagonistas de los receptores de angiotensina II durante las primeras 24 horas fue superior al 90% en toda la muestra. Conclusiones: Se alcanzó un nivel superior de cumplimiento de las medidas de desempeño de la atención de los síndromes coronarios agudos después de la implementación de una ruta crítica

Novel N-Benzoyl-2-hydroxybenzamide disrupts unique parasite secretory pathway

Toxoplasma gondii is a protozoan parasite that can damage the human brain and eyes. There are no curative medicines. Herein, we describe our discovery of N-benzoyl-2-hydroxybenzamides as a class of compounds effective in low nanomolar range against T. gondii in vitro and in vivo. Our lead compound QQ-437 displays robust activity against the parasite, useful as a new scaffold for development of novel and improved inhibitors of T. gondii. Our genome-wide investigations reveal a specific mechanism of resistance to N-benzoyl-2-hydroxybenzamides mediated by Adaptin-3β, a large protein from the secretory protein complex. N-benzoyl-2-hydroxybenzamide -resistant clones have alterations of their secretory pathway which traffics proteins to micronemes, rhoptries, dense granules and acidocalcisome/Plant-Like Vacuole (PLV). N-benzoyl-2-hydroxybenzamide treatment also alters micronemes, rhoptries, the contents of dense granules and most markedly acidocalcisomes/PLV. Furthermore, QQ-437 is active against chloroquine-resistant Plasmodium falciparum. Our studies reveal a novel class of compounds that disrupts a unique secretory pathway of T. gondii, with potential to be used as scaffolds to discover improved compounds to treat the devastating diseases caused by apicomplexan parasites

Caracterización genética del patosistema Phytophthora infestans Solanum tuberosum y su relación con polimorfismos moleculares (fase II)

IP 1118-12-154-99v.1. Informe tecnico final -- v.2. Late blight: managing the global threat/ Lizarraga Charlotte.de la resistencia al tizon tardio y compatibilidad al patogenoPhytophthora infestans de gentoios de la;coleccion central colombiana de papa. / J.L. Zapata, Ofelia Trillos. -- En: Congreso Ascolfi. (21 : 2000,;ago.30-sep.1 : Palmira) -- [s.l.] : Ascolfi, 2000 -- p. 46--Razas Fisiologicas y tipo de apareamiento de;Phytophthora infestans (Mont.) de Barry en diferentes pisos termicos y hospedantes, en el oriente antioqueño.;/ S. Jaramillo, J. Zapata. -- En: Congreso Ascolfi. (21 :2000,ago.30-sep.1 : Palmira) -- s.l : Ascolfi, 2000;cm.;PONENCIA(S) EN CONGRESO: Caracterizacion del hongo Phytophthorainfestansen Colombia / Sonia Jaramillo V.;on Phytophthora infestans in Colombia: Host-Pathogen Coevolutionin the Andean Mountains / J.G. Morales ...;[et al.] -- En: Late blight: managing the global threat. Proceedings of the Global Initiative on Late Blight;Conference, 11-13 July 2002, Hamburg, Germany / Gilb'02 Conference Late Blight Managing the Global Threat ;editor Charlotte Lizarraga (2002 Jul. 11-13 : Hamburg, Germany).'-- Hamburg : 181-- p. ; 28 cm. -- Evaluacion;... [et al.] -- p. 46-47. -- En: La Biotecnologia en el desarrollo del pais / Congreso colombiano de;Biotecnologia (1 : 2002 jun. 26-28 : Bogotá) -- Bogotá : Universidad Nacional de Colombia, 2002. ; 28 cm. --;Caracterizacion de aislamientos de Phytophthora infestansportecnicas basadas en pcr y por resistencia a;fungicidas en Colombia / Jaramillo S. ... [et al.] -- En:Memorias ALAP /Congreso de la asociacion;latinoamericana de la papa. (19 : 2000 feb. 28 - mar. 3 :Ciudadde la Habana) -- Ciudad de la Habana, Cuba,;2000. -- p. ; 28 cm. -- Evaluacion de aislamientos colombianosde Phytophthora infestans por tipo de;apareamiento / Jaramillo S., Gilchrist, E., Afanador, L. -'- p.48. -- En:Nuevas tendencias en Fitopatologia /;Congreso ASCOLFI (23 : 2002 jul. : Bogotá). -- Bogotá : Universidad Nacional de Colombia, 2002. -- p. ; 28 cm.;'-- evaluacion de La diversidad genetica y patogenica de Las poblaciones del hongo Phytophthora infestans;(Mont.) de Bary en Antioquia / Gilchrist, E. ... [et al.]'-- en:Salud publica para los vegetales / Congreso;de la asociacion colombiana de fitopatologia y ciencias afines.(22 : 2001jul. 11-13 : Medellin). -- Medellin;: Universidad Nacional de Colombia, 2001. -- p. ; 28 cm. -'- Razas fisiologicas y tipo de apareamiento de;Phytophthora infestans (Mont.) de Bary en diferentes pisostermicos y hospedantes en el oriente antioqueño /;Marin M. ... [et al.] -- En: Patologia de la postcosecha en flores, frutales, hortalizas, semillas, raices y;tuberculos / Congreso de la asociacion colombiana de fitopatologia y ciencias afines. (21 : 2000 ago. 30 -;sep. 1 : Palmira) -- Palmira : Centro internacional de agricultura tropical, 2000. -- p. ; 28 cm. -- Researc

The benzimidazole based drugs show good activity against T. gondii but poor activity against its proposed enoyl reductase enzyme target

The enoyl acyl-carrier protein reductase (ENR) enzyme of the apicomplexan parasite family has been intensely studied for antiparasitic drug design for over a decade, with the most potent inhibitors targeting the NAD(+) bound form of the enzyme. However, the higher affinity for the NADH co-factor over NAD(+) and its availability in the natural environment makes the NADH complex form of ENR an attractive target. Herein, we have examined a benzimidazole family of inhibitors which target the NADH form of Francisella ENR, but despite good efficacy against Toxoplasma gondii, the IC50 for T. gondii ENR is poor, with no inhibitory activity at 1μM. Moreover similar benzimidazole scaffolds are potent against fungi which lack the ENR enzyme and as such we believe that there may be significant off target effects for this family of inhibitors