ABSTRACT
Proteins containing WD40 domains play important roles in the formation of multiprotein complexes. Little is known about WD40 proteins in the malaria parasite. This report contains the initial description of a WD40 protein that is unique to the genus Plasmodium and possibly closely related genera. The N-terminal portion of this protein consists of seven WD40 repeats that are highly conserved in all Plasmodium species. Following the N-terminal region is a central region that is conserved within the major Plasmodium clades, such as parasites of great apes, monkeys, rodents, and birds, but partially conserved across all Plasmodium species. This central region contains extensive low-complexity sequence and is predicted to have a disordered structure. Proteins with disordered structure generally function in molecular interactions. The C-terminal region is semi-conserved across all Plasmodium species and has no notable features. This WD40 repeat protein likely functions in some aspect of parasite biology that is unique to Plasmodium and this uniqueness makes the protein a possible target for therapeutic intervention.
Subject(s)
Plasmodium/genetics , Protozoan Proteins/isolation & purification , WD40 Repeats , Amino Acid Sequence , Animals , Birds , Cloning, Molecular , Epitopes/chemistry , Gene Expression Regulation , Models, Chemical , Parasites/metabolism , Peptide Hydrolases/chemistry , Plasmodium/classification , Proteins , Protozoan Proteins/chemistry , Protozoan Proteins/genetics , Protozoan Proteins/physiology , Two-Hybrid System TechniquesABSTRACT
The malarial parasite remodels the host erythrocyte following invasion. Well-known examples are adhesive proteins inserted into the host erythrocyte membrane, which function as virulence factors. The modification of the host erythrocyte may be mediated by a specialized domain of the endoplasmic reticulum, or Plasmodium export compartment (PEC). Previously, monoclonal antibodies recognizing the PEC were generated and one of these monoclonal antibodies recognize a 68 kDa parasite protein. In this study, the 68 kDa protein was affinity purified and analyzed by peptide mapping using mass spectrometry. The results demonstrate that the 68 kDa protein is the P. falciparum homolog of the endoplasmic reticulum resident HSP70 called PfHSP70-2. This finding is consistent with the PEC being a domain of the endoplasmic reticulum and suggests a role for PfHSP70-2 in the export of Plasmodium proteins into the host erythrocyte.
ABSTRACT
INTRODUCTION: The quantitation of glucose consumption in animal cell cultures is mainly based on the use of radiolabeled or fluorescent analogues, resulting in expensive and tedious procedures, requiring special equipment and, sometimes, with potential health and environmental risks. OBJECTIVES: The objective of this work was to evaluate the application of a blood plasma colorimetric assay to quantify glucose consumption in in vitro cultures of adipose cells. METHODS: We worked with 3T3-L1 adipose cells differentiated by 7-8 days, which were exposed to different initial glucose concentrations (5.5, 2.8 and 1.4 mM) for variable times, either in the absence or the presence of 100 nM insulin. Using a commercial colorimetric glucose assay, extracellular glucose was determined, and glucose uptake was calculated as the difference between the initial and final glucose concentration. RESULTS: The colorimetric assay allowed us to quantify glucose uptake in our cell model, observing a linear response over time (r 2 ≥0.9303) to the different glucose concentrations, both in the basal and insulin-induced condition. The insulin-stimulated glucose consumption was higher than basal consumption at all glucose concentrations evaluated, but significant differences were observed at 120-, 360- and 480-min in glucose 5.5 mM (p ≤ 0.01, n = 5), and 240 min in glucose 1.4 mM (p ≤ 0.01, n = 5). A V max of 4.1 and 5.9 nmol/ml/min (basal and insulin-induced, respectively) and a K m of 1.1 mM (same in basal vs insulin-stimulated) were calculated. The bioassay was also useful in a pharmacological context: in glucose 1.4 mM, glucose consumption showed an effect that depended on insulin concentration, with a calculated EC50 of 18.4 ± 1.1 nM. CONCLUSIONS: A simple and low-cost bioassay is proposed to quantify glucose consumption in 3T3-L1 adipose cells.
ABSTRACT
Objetivo: el objetivo de este estudio fue analizar el genotipo y susceptibilidad antimicrobiana de Pseudomonas aeruginosa de pacientes con fibrosis quística y otras patologías. Materiales y métodos: se analizaron 20 aislados de pacientes con fibrosis quística y 20 de pacientes con otras enfermedades por medio de la prueba de susceptibilidad antimicrobiana por microdilución en caldo y técnica del ADN polimorfo amplificado aleatorio. Resultados: se observó que los aislados de pacientes con fibrosis quística presentaron mayor resistencia (56 %) en comparación con aislados de pacientes sin fibrosis quística (25 %). Los antimicrobianos más efectivos en ambos grupos fueron cefepima, ceftriaxona y meropenem. Desde el punto de vista genotípico, se observa heterogeneidad entre las cepas de pacientes con fibrosis quística y dos grupos con cepas idénticas de origen hospitalario, lo que sugiere una posible transmisión cruzada. Conclusión: Concluimos que los porcentajes de resistencia de Pseudomonas aeruginosa en este estudio son altas, y este hallazgo se acentúa en el caso de pacientes con fibrosis quística, lo cual deja muy pocas opciones de tratamiento. La tipificación por técnica del ADN polimórfico amplificado aleatorio permitió conocer la variabilidad de genotipos para tener control sobre la transmisión de cepas, lo cual constituye un tópico de importancia en el sistema de salud y el mejoramiento de la calidad de vida de los pacientes.
Objective: Our aim was to analyze genotype and antimicrobial susceptibility of Pseudo-monas aeruginosa from cystic fibrosis patients and other diseases. Materials and methods: We analyzed 20 isolates from cystic fibrosis patients and 20 from patients with other diseases by dilution antimicrobial susceptibility test and random amplified polymorphic DNA technique. Results: We found that isolates from cystic fibrosis patients had higher resistance (56 %) than isolates from patients without cystic fibrosis (26 %). The most effective antimicrobi-als in both groups were cefepime, ceftriaxone and meropenem. With regard to the geno-type, we observed heterogeneity between strains from cystic fibrosis patients and two clus-ters with identical strains from hospital origin, suggesting a possible cross transmission. Conclusion: We concluded that the resistance rate of Pseudomonas aeruginosa in this study was high and this finding is accentuated in patients with cystic fibrosis, leaving few treatment options. Typification by random amplified polymorphic DNA technique allowed us to know the variability of genotypes to control strain transmission; this is an important topic to optimize health services and the quality of life of our patients.
ABSTRACT
Las infecciones nosocomiales constituyen un importante problema de salud, cuyos factores de riesgo son hospitalizaciones prolongadas, procedimientos invasivos y tratamientos antimicrobianos de amplio espectro. Pseudomonas aeruginosa y Candida albicans son microorganismos frecuentemente aislados del tracto respiratorio de pacientes gravemente enfermos. Se ha demostrado que estos patógenos pueden tener una interacción de gran significancia en donde las características morfológicas y de virulencia de cada microorganismo se modulan mutuamente aumentando significativamente el riesgo y la severidad de las infecciones urinarias y respiratorias produciendo una alta morbimortalidad. El objetivo de este trabajo fue ilustrar las características microbiológicas y clínicas que son resultado de la presencia conjunta de P. aeruginosa y C. albicans en pacientes gravemente enfermos en hospitales de Cartagena de Indias (Colombia). En todos los casos se destaca un proceso bacteriano inicial, en este caso causado por P. aeruginosa, que fue tratado de acuerdo a la susceptibilidad antimicrobiana encontrada y al disminuir el agente bacteriano responsable se dio lugar al crecimiento de C. albicans y al desarrollo de una nueva infección que empeoró la condición clínica de estos pacientes. Las infecciones conjuntas entre P. aeruginosa y C. albicans siempre se deben sospechar en un paciente hospitalizado, especialmente en unidades de cuidados intensivos y cuando hagan uso de sondas, catéteres y otros materiales para estudios invasivos, pues estos microorganismos son de naturaleza oportunista y claramente pueden empeorar el pronóstico y llevar a complicaciones a pacientes que han sido hospitalizado por causas diferentes o enfermedades de baja complejidad, prolongando el tiempo de hospitalización y aumentando costos.
