Removal of Erythromycin from Water by Ibuprofen-Driven Pre-Organized Divinyl Sulfone Cross-Linked Dextrin.

Water recycling and reuse are cornerstones of water management, which can be compromised by the presence of pollutants. Among these, pharmaceuticals can overcome standard water treatments and require sophisticated approaches to remove them. Sorption is an economically viable alternative limited by the need for sorbents with a sorption coefficient (Kd) higher than 500 L/kg. The cross-linking of dextrin (Dx) with divinyl sulfone (DVS) in the presence of 1 mmol or 5 mmol of ibuprofen (IBU) yields the insoluble polymers pDx1 and pDx5 with improved affinity for IBU and high selectivity towards erythromycin (ERY) and ERY Kd higher than 4 × 103 L/kg, when tested against a cocktail of six drugs. Characterization of the polymers shows that both pDx1 and pDx5 have similar properties, fast sorption kinetics, and ERY Kd of 13.3 × 103 for pDx1 and 6.4 × 103 for pDx5, representing 26.6 and 12.0 times the 500 L/kg threshold. The fact that new affinities and improvements in Kd can be achieved by cross-linking Dx in the presence of other molecules that promote pre-organization expands the applications of DVS cross-linked polysaccharides as sustainable, scalable, and environmentally friendly sorbents with a potential application in wastewater treatment plants (WTPs).

Nitro-Oleic Acid-Mediated Nitroalkylation Modulates the Antioxidant Function of Cytosolic Peroxiredoxin Tsa1 during Heat Stress in Saccharomyces cerevisiae.

Heat stress is one of the abiotic stresses that leads to oxidative stress. To protect themselves, yeast cells activate the antioxidant response, in which cytosolic peroxiredoxin Tsa1 plays an important role in hydrogen peroxide removal. Concomitantly, the activation of the heat shock response (HSR) is also triggered. Nitro-fatty acids are signaling molecules generated by the interaction of reactive nitrogen species with unsaturated fatty acids. These molecules have been detected in animals and plants. They exert their signaling function mainly through a post-translational modification called nitroalkylation. In addition, these molecules are closely related to the induction of the HSR. In this work, the endogenous presence of nitro-oleic acid (NO2-OA) in Saccharomyces cerevisiae is identified for the first time by LC-MS/MS. Both hydrogen peroxide levels and Tsa1 activity increased after heat stress with no change in protein content. The nitroalkylation of recombinant Tsa1 with NO2-OA was also observed. It is important to point out that cysteine 47 (peroxidatic) and cysteine 171 (resolving) are the main residues responsible for protein activity. Moreover, the in vivo nitroalkylation of Tsa1 peroxidatic cysteine disappeared during heat stress as the hydrogen peroxide generated in this situation caused the rupture of the NO2-OA binding to the protein and, thus, restored Tsa1 activity. Finally, the amino acid targets susceptible to nitroalkylation and the modulatory effect of this PTM on the enzymatic activity of Tsa1 are also shown in vitro and in vivo. This mechanism of response was faster than that involving the induction of genes and the synthesis of new proteins and could be considered as a key element in the fine-tuning regulation of defence mechanisms against oxidative stress in yeast.

Poly(ethylene-imine)-Functionalized Magnetite Nanoparticles Derivatized with Folic Acid: Heating and Targeting Properties.

Magnetite nanoparticles (MNPs) coated by branched poly (ethylene-imine) (PEI) were synthesized in a one-pot. Three molecular weights of PEI were tested, namely, 1.8 kDa (sample MNP-1), 10 kDa (sample MNP-2), and 25 kDa (sample MNP-3). The MNP-1 particles were further functionalized with folic acid (FA) (sample MNP-4). The four types of particles were found to behave magnetically as superparamagnetic, with MNP-1 showing the highest magnetization saturation. The particles were evaluated as possible hyperthermia agents by subjecting them to magnetic fields of 12 kA/m strength and frequencies ranging between 115 and 175 kHz. MNP-1 released the maximum heating power, reaching 330 W/g at the highest frequency, in the high side of reported values for spherical MNPs. In vitro cell viability assays of MNP-1 and MNP-4 against three cell lines expressing different levels of FA receptors (FR), namely, HEK (low expression), and HeLa (high expression), and HepG2 (high expression), demonstrated that they are not cytotoxic. When the cells were incubated in the presence of a 175 kHz magnetic field, a significant reduction in cell viability and clone formation was obtained for the high expressing FR cells incubated with MNP-4, suggesting that MNP-4 particles are good candidates for magnetic field hyperthermia and active targeting.

Carbon dots-inspired fluorescent cyclodextrins: competitive supramolecular "off-on" (bio)sensors.

Chromophore-appended cyclodextrins combine the supramolecular loading capabilities of cyclodextrins (CDs) with the optical properties of the affixed chromophores. Among fluorescent materials, carbon dots (CNDs) are attractive and the feasibility of CND-appended CDs as sensors has been demonstrated by different authors. However, CNDs are intrinsically heterogeneous materials and their ulterior functionalization yields hybrid composites that are not well defined in terms of structure and composition. Inspired by the fluorescence properties of 5-oxo-1,2,3,5-tetrahydroimidazo[1,2-a]pyridine-7-carboxylic acid (IPCA), the most paradigmatic of the molecular fluorophores detected in CNDs, herein we report two highly efficient synthetic chemical strategies for the preparation of IPCA-appended CDs that behave as CND-based CD "turn off-on" biosensors suitable for the analysis of cholesterol and ß-galactosidase activity. We have deconstructed the CND-CD systems to demonstrate that (i) the role of CNDs is limited to acting as a support for the molecular fluorophores produced during their synthesis and (ii) the molecular fluorophores suffice for the determination of the enzymatic activity based on the quenching by p-nitrophenol as a sacrificial quencher.

Cytomegalovirus disease in patients with hematopoietic stem cell transplantation, experience over 8 years

Abstract Objective Cytomegalovirus infection and disease are significant causes of morbidity and mortality among patients with hematopoietic stem cell transplantation. The aim of this study was to assess the frequency of cytomegalovirus infection and characterize the patients who developed the disease. Methods A retrospective cohort study was performed among adult patients, recipients of allogeneic HSTC between 2008 and 2015. Taking into account the institutional protocol of prophylaxis infections in hematopoietic stem cell transplantation, patients received either preemptive therapy or prophylaxis with valganciclovir. Infection was defined as a positive pp65 antigenemia assay or PCR higher than 500 copies/mL. Disease was defined as viremia with evidence of end organ damage. Results Seventy patients were included, the median age was 36 years old (IQR 17-62). A total of 93% of the recipients had a positive serology. The Cytomegalovirus infection occurred in 59% of the patients. Eleven patients developed disease (16%), the most frequent manifestation being colitis, followed by pneumonitis and a single case of retinitis. There were no differences between the preemptive therapy or prophylaxis groups. The mean time of onset of the disease was day 94 post-transplant. Three patients developed disease with a viral load lower than 1000 copies/mL. Conclusion The incidence of cytomegalovirus infection after transplantation at our institution is high. It was found that the disease can occur with any level of viral load and is associated with high mortality.

Cytomegalovirus disease in patients with hematopoietic stem cell transplantation, experience over 8 years.

OBJECTIVE: Cytomegalovirus infection and disease are significant causes of morbidity and mortality among patients with hematopoietic stem cell transplantation. The aim of this study was to assess the frequency of cytomegalovirus infection and characterize the patients who developed the disease. METHODS: A retrospective cohort study was performed among adult patients, recipients of allogeneic HSTC between 2008 and 2015. Taking into account the institutional protocol of prophylaxis infections in hematopoietic stem cell transplantation, patients received either preemptive therapy or prophylaxis with valganciclovir. Infection was defined as a positive pp65 antigenemia assay or PCR higher than 500copies/mL. Disease was defined as viremia with evidence of end organ damage. RESULTS: Seventy patients were included, the median age was 36 years old (IQR 17-62). A total of 93% of the recipients had a positive serology. The Cytomegalovirus infection occurred in 59% of the patients. Eleven patients developed disease (16%), the most frequent manifestation being colitis, followed by pneumonitis and a single case of retinitis. There were no differences between the preemptive therapy or prophylaxis groups. The mean time of onset of the disease was day 94 post-transplant. Three patients developed disease with a viral load lower than 1000copies/mL. CONCLUSION: The incidence of cytomegalovirus infection after transplantation at our institution is high. It was found that the disease can occur with any level of viral load and is associated with high mortality.

Acid anhydride coated carbon nanodots: activated platforms for engineering clicked (bio)nanoconstructs.

Activated carbon nanodots functionalized with acid anhydride groups (AA-CNDs) are prepared by one-pot water-free green thermolysis of citric acid. As a proof of concept of their capabilities as appealing and versatile platforms for accessing engineering nanoconstructs, the as-prepared AA-CNDs have been reacted to yield clickable CNDs. Their click bioconjugation with relevant recognizable complementary clickable sugars has led to multivalent CND-based glyconanoparticles that are non-toxic and biorecognizable. The accessibility and intrinsic reactivity of AA-CNDs expand the current toolbox of covalent surface grafting methodologies and provide a wide range of potential applications for engineering (bio)nanoconstructs.

Trasplante haploidéntico de progenitores hematopoyéticos en pacientes con diagnóstico de leucemia mieloide aguda / Haploidentical transplantation of hematopoietic progenitors in patients diagnosed with acute myeloid leukemia

Resumen Introducción: En pacientes con leucemia mieloide aguda (LMA) el trasplante de progenitores hematopoyético (TPH) es el único tratamientoz curativo. El objetivo de este estudio es presentar la experiencia y resultados del trasplante haploidéntico en pacientes adultos con LMA en la Fundación Valle del Lili, Cali - Colombia. Materiales y métodos: Estudio de cohorte retrospectivo de pacientes que recibieron trasplante haploidéntico entre 2013 y 2017, con acondicionamiento mieloablativo y ciclofosfamida postrasplante, en Fundación Valle del Lili, Cali (Colombia). Resultados: Se realizaron 47 trasplantes en pacientes con leucemia mieloide aguda en la fecha de estudio, se incluyeron en el análisis 21 pacientes con donante haploidéntico, a 3 años tanto la supervivencia global y libre de eventos fue del 38%. La incidencia acumulada de mortalidad relacionada al trasplante fue del 26% a 100 días y del 38,3%, a 38 meses de seguimiento. La incidencia acumulada de recaída a 38 meses fue del 19%. Con respecto a la enfermedad injerto versus huésped (EICH) se encontró que la incidencia acumulada de EICH aguda grado II-IV, grado III-IV y EICH crónico fue del 19%, 5% y 19% respectivamente. Conclusión: Los resultados de este estudio sugieren que el trasplante haploidéntico es una alternativa factible como tratamiento para pacientes con diagnóstico de LMA en nuestro medio.

Abstract Introduction: In patients with acute myeloid leukemia (AML), hematopoietic progenitor transplantation (PHT) is the only curative treatment. The objective of this study is to present the experience and results of haploidentical transplantation in adult patients with AML at the Valle del Lili Foundation, Cali - Colombia. Materials and methods: Retrospective cohort study of patients who received haploidentical transplantation between 2013 and 2017, with myeloablative conditioning and post-transplant cyclophosphamide, in Fundación Valle del Lili, Cali (Colombia). Results: 47 transplants were performed in patients with acute myeloid leukemia on the study date, 21 patients with haploidentical donors were included in the analysis, at 3 years both overall and event-free survival was 38%. The cumulative incidence of transplant-related mortality was 26% at 100 days and 38.3% at 38 months of follow-up. The cumulative incidence of relapse at 38 months was 19%. Regarding graft versus host disease (GVHD), it was found that the cumulative incidence of acute GVHD grade II-IV, grade III-IV and chronic GVHD was 19%, 5% and 19% respectively. Conclusion: The results of this study suggest that haploidentical transplantation is a feasible alternative as a treatment for patients diagnosed with AML in our environment.

Novel Promising Estrogenic Receptor Modulators: Cytotoxic and Estrogenic Activity of Benzanilides and Dithiobenzanilides.

The cytotoxicity of 27 benzanilides and dithiobenzanilides built on a stilbene scaffold and possessing various functional groups in aromatic rings previously described for their spasmolytic properties was assayed on three human cancer cell lines (A549 -lung adenocarcinoma, MCF-7 estrogen dependent breast adenocarcinoma and MDA-MB-231 estrogen independent breast adenocarcinoma) and 2 non-tumorigenic cell lines (CCD39Lu-lung fibroblasts, MCF-12A - breast epithelial). Three compounds (6, 15 and 18) showed selective antiproliferative activity against estrogen dependent MCF-7 cancer cells and their estrogenic activity was further confirmed in MCF-7 transfected with an estrogen receptor reporter plasmid and in HEK239 cells over-expressing the estrogen receptor alpha (ERα). Compound 18 is especially interesting as a potential candidate for therapy since it is highly toxic and selective towards estrogen dependent MCF7 cell lines (IC50 = 5.07 µM versus more than 100 µM for MDA-MB-231) and almost innocuous for normal breast cells (IC50 = 91.46 µM for MCF-12A). Docking studies have shown that compound 18 interacts with the receptor in the same cavity as estradiol although the extra aromatic ring is involved in additional binding interactions with residue W383. The role of W383 and the extended binding mode were confirmed by site-directed mutagenesis.

Curso clínico de pacientes de trasplante autógeno de médula ósea portadores del virus linfotrópico humano / Clinical evolution of carriers of human T-lymphotropic virus 1 after autologous hematopoietic stem cell transplantation

La infección por virus linfotrópico humano 1 es frecuente en la costa pacífica colombiana y se ha relacionado con leucemia/linfoma de células T del adulto y mielopatía en una proporción baja de los seropositivos. En pacientes con trasplante de órganos sólidos pareciera que estas patologías se desarrollan más rápidamente que en los otros escenarios pero se desconoce el curso de la infección por virus linfotrópico humano 1 en trasplante de médula ósea por lo cual describimos 3 casos de pacientes seropositivos y linfoma que fueron llevados a trasplante autógeno. Uno de ellos tuvo recaída de su patología hematológica y falleció a consecuencia de la misma, otra paciente presentó un cuadro compatible con mielopatía asociada al virus linfotrópico humano 1 y la última, una enfermedad injerto contra hospedero. En las personas seropositivas y que necesitan un trasplante de células hematopoyéticas se requiere una búsqueda activa de este virus para hacer seguimientos y evaluar su impacto real en los desenlaces y saber si el curso de la infección podría cambiar con el régimen condicionante del trasplante.

Human T-lymphotropic virus 1 infection is common in Colombia´s Pacific coast and has been linked to adult T-cell leukemia/lymphoma and human T-lymphotropic virus 1-associated myelopathy in a low percentage of cases. In patients with solid organ transplantation, these diseases occur more quickly than in other scenarios but in bone marrow transplantation the true impact is unknown. We describe 3 seropositive patients with lymphoma who underwent autologous stem cell transplantation; in one case there was relapse of the hematologic malignancy and death occurred as a result. Another patient had symptoms compatible with human T-lymphotropic virus 1-associated myelopathy and the last patient had a graft vs. host disease. In seropositive people who need hematopoietic cell transplantation, an active search for this virus is required to be able to follow and assess the virus´s impact on outcomes, as well as to assess whether the evolution could change according to the transplant conditioning regimen.

Divinyl sulfone cross-linked cyclodextrin-based polymeric materials: synthesis and applications as sorbents and encapsulating agents.

The aim of this study was to evaluate the crosslinking abilities of divinyl sulfone (DVS) for the preparation of novel water-insoluble cyclodextrin-based polymers (CDPs) capable of forming inclusion complexes with different guest molecules. Reaction of DVS with native α-cyclodextrin (α-CD), ß-cyclodextrin (ß-CD) and/or starch generates a variety of homo- and hetero-CDPs with different degrees of crosslinking as a function of the reactants' stoichiometric ratio. The novel materials were characterized by powder X-ray diffraction, electron microscopy and for their sorption of phenol and 4-nitrophenol. They were further evaluated as sorbents with phenolic pollutants (bisphenol A and ß-naphthol) and bioactive compounds (the hormone progesterone and curcumin). Data obtained from the inclusion experiments show that the degree of cross-linking has a minor influence on the yield of inclusion complex formation and highlight the important role of the CDs, supporting a sorption process based on the formation of inclusion complexes. In general, the inclusion processes are better described by a Freundlich isotherm although an important number of them can also be fitted to the Langmuir isotherm with R2 ≥ 0.9, suggesting a sorption onto a monolayer of homogeneous sites.

In vitro and in vivo evaluation of novel cross-linked saccharide based polymers as bile acid sequestrants.

Bile acid sequestrants (BAS) represent a therapeutic approach for the management of hypercholesterolemia that relies on the cationic polymeric nature of BAS to selectively bind negatively charged bile acids. We hypothesized that the cross-linking of ß-cyclodextrin (ß-CD) and saccharides such as starch or dextrin with divinyl sulfone (DVS) yields homo- and hetero-polymeric materials with the ability to trap sterols. Our hypothesis was put to test by synthesizing a library of 22 polymers that were screened to evaluate their capability to sequester both cholesterol (CHOL) and cholic and deoxycholic acids (CA and DCA). Three polymers synthesized in high yield were identified as promising. Two were neutral hetero-polymers of ß-CD and starch or dextrin and the third was a weakly cationic homo-polymer of starch, highlighting the importance of the cavity effect. They were tested in hypercholesterolemic male Wistar rats and their ability to regulate hypercholesterolemia was similar to that for the reference BAS cholestyramine, but with two additional advantages: (i) they normalized the TG level and (ii) they did not increase the creatinine level. Neither hepatotoxicity nor kidney injury was detected, further supporting them as therapeutical candidates to manage hypercholesterolemia.

Masked thiol sugars: chemical behavior and synthetic applications of S-glycopyranosyl-N-monoalkyl dithiocarbamates.

The chemical behavior of S-glycopyranosyl-N-monoalkyl dithiocarbamates (DTCs) as masked 1-glycosyl thiols, easily prepared by the nucleophilic displacement of 1-halo sugars with dithiocarbamate salts of primary amines, has been studied and synthetically exploited. This behavior relies on the abstraction of the proton of the carbamate functionality that allows controlled access to thiolate sugar intermediates. The basic character of the DTC salts used as reagents leads to thiolates that evolve in situ to symmetrical diglycosyldisulfides (DGDSs) when long reaction times are allowed. Alternatively, controlled unmasking of the thiolate function can be efficiently attained by treatment with an external base of isolated anomeric glycosyl DTCs, the formation of which is prevalent when using short reaction times. In this manner, a second methodology for the preparation of symmetrical DGDSs and a chemical protocol for the S-glycosylation of any electrophilic substrate are established. The applications of this last strategy for the preparation of thioglycosyl vinyl sulfones, thiodisaccharides, and S-linked homo- and heterodivalent neoglycoconjugates are described as a proof-of-concept of the great potential of the sugar DTCs in any chemical scenario in which the covalent attachment of a thiol sugar is required. The evaluation of the biological functionality of some divalent sulfurated sugar systems is also described.

Vinyl sulfone functionalization: a feasible approach for the study of the lectin-carbohydrate interactions.

Carbohydrate-mediated molecular recognition is involved in many biological aspects such as cellular adhesion, immune response, blood coagulation, inflammation, and infection. Considering the crucial importance of such biological events in which proteins are normally involved, synthetic saccharide-based systems have emerged as powerful tools for the understanding of protein-carbohydrate interactions. As a new approach to create saccharide-based systems, a set of representative monosaccharides (D-mannose, D-glucose, N-acetyl-D-glucosamine, and L-fucose) and disaccharides (lactose, maltose, and melibiose) were derivatized at their anomeric carbon with a vinyl sulfone group spanned by an ethylthio linker. This vinyl sulfone functionalization is demonstrated to be a general strategy for the covalent linkage of a saccharide in mild conditions via Michael-type additions with the amine and thiol groups from functionalized supports and those naturally present in biomolecules. The introduction of the ethylthio linker between the biorecognizable element (i.e., saccharide) and the reactive group (i.e., vinyl sulfone) was found to preserve the functionality of the former. The capability of the vinyl sulfone saccharides for the study of lectin-carbohydrate interactions was demonstrated by (i) immobilizing them on both amine-functionalized supports (glass slides and microwell plates) and polylysine-coated glass slides to create sugar arrays that selectively bind lectins (ii) coupling to model proteins to yield neoglycoproteins that are recognized by lectins and (iii) using vinyl sulfone saccharides as tags to allow the detection of the labeled biomolecule by HRP-lectins. The above results were further put tothe test with a real case: detection of carbohydrate binding proteins present in rice ( Oryza sativa ).

Vinyl sulfone bifunctional tag reagents for single-point modification of proteins.

The introduction of multiple labels onto biomolecules is a challenge. We report herein the synthesis of vinyl sulfone derivatized bifunctional tag single-attachment-point reagents (BTSAP) bearing biotin and a fluorescent tag and their applications in proteins for the introduction of multiple labels by means of the Michael-type addition of the electrophilic vinyl sulfone group. These BTSAP reagents were easily synthesized by a two-step chemical strategy involving the preparation of alkyne vinyl sulfone derivatized tags (AVST) and subsequent click CuAAC attachment of a second azide functionalized tag. The direct coupling of BTSAP reagents with the low reactive protein horseradish peroxidase (HRP) turned it into a dual reporter group (i.e., fluorescence and peroxidase activity) that may be coupled to any recognition system via biotin-avidin affinity. The AVST compounds are not mere synthetic intermediates for the preparation of BTSAP reagents but valuable clickable self-reporting compounds that allow the simultaneous introduction in proteins of an alkyne function and labeling when conjugated via the vinyl sulfone group. The implementation of these clickable AVST compounds in a CuAAC-based sequential approach also allows attainment of the dual labeling of HRP. This approach yields equivalent results in terms of fluorescent labeling, specific activity, and functionality of the biotin tag when compared with the direct bifunctional labeling by the BTSAP reagent. However, for life science this direct approach is more convenient since it avoids the use of copper catalysis, overcoming the toxicity drawback of this metal in biological systems.

Characterization of plant sulfiredoxin and role of sulphinic form of 2-Cys peroxiredoxin.

The antioxidant function of 2-Cys peroxiredoxin (Prx) involves the oxidation of its conserved peroxidatic cysteine to sulphenic acid that is recycled by a reductor agent. In conditions of oxidative stress, the peroxidatic cysteine can be overoxidized to sulphinic acid inactivating the Prx. An enzyme recently discovered, named sulfiredoxin (Srx), reduces the sulphinic 2-Cys Prx (Prx-SO(2)H). To explore the physiological functions of Srx in plants we have cloned, expressed and purified to homogeneity a Srx from Arabidopsis thaliana (AtSrx), as well as five variants by site-directed mutagenesis on amino acids involved in its activity. The activity of sulfiredoxin, determined by a new method, is dependent on the concentration of the sulphinic form of Prx and the conserved Srx is capable of regenerating the functionality of both pea and Arabidopsis Prx-SO(2)H. Molecular modelling of AtSrx and the facts that the R28Q variant shows a partial inactivation, that the activity of the E76A variant is equivalent to that of the native enzyme and that the double mutation R28Q/E76A abolishes the enzymatic activity suggests that the pair His100-Glu76 may be involved in the activation of C72 in the absence of R28. The knock-out mutant plants without Srx or 2-Cys Prx exhibited phenotypical differences under growth conditions of 16 h light, probably due to the signalling role of the sulphinic form of Prx. These mutants showed more susceptibility to oxidative stress than wild-type plants. This work presents the first systematic biochemical characterization of the Srx/Prx system from plants and contributes to a better understanding of its physiological function.

Células T reguladoras, infección y autoinmunidad: implicaciones en terapéutica / Regulatory T cells, Infection and Autoimmunity. Therapeutic implications

El entendimiento del equilibrio del sistema inmune es, además de una pregunta aún no resuelta, una esperanza para el principio de la terapéutica en enfermedades que le siguen ganando la batalla al ejercicio médico. La respuesta inmune innata permite la diferenciación de lo propio y lo extraño mediante receptores de reconocimiento de patrones moleculares asociados a patógenos que activan las células presentadoras de antígeno cuando se unen con moléculas estructural y químicamente conservadas entre los patógenos. Sin embargo, el sistema inmune se torna tan complejo que estos controles iniciales no son suficientes para un funcionamiento perfecto. La presencia de enfermedades autoinmunes continúa sin una explicación absoluta y la señal de cuándo apagar una respuesta inmune no está completamente entendida hasta ahora. El redescubrimiento de las células T reguladoras satisface no sólo explicaciones del equilibrio inmune sino que también se convierte en un blanco terapéutico muy seductor para el anhelado control de la respuesta inflamatoria, fenómenos infecciosos y autoinmunes. Consecuente con esto, la célula T reguladora explicaría cómo las infecciones que estimulan su proliferación puedan ser protectoras de autoinmunidad independiente de la carga genética o medio ambiente en que se desarrolle el individuo. Las infecciones que, por el contrario, eliminen o inactiven las células T reguladoras, favorecen la presencia de autoinmunidad. Se consultaron únicamente artículos en inglés o español en la bases de datos PubMed hasta la fecha de envío del artículo.

The mechanisms underlying the control of the immune system are still incompletely solved. The treatment of many human diseases is still a medical challenge. The innate immune system recognizes the difference between self and non-self antigens through the binding of pathogen associated molecular patterns to pattern recognition receptors present on the antigen presenting cells. The recent rediscovered regulatory T cells participate in the immune system homeostasis. On the other hand, regulatory T cells may be incriminated in the pathology of both inflammatory and infectious diseases. Thus, these cells would be a suitable target for the treatment of diseases in which they are involved. The participation of regulatory T cells in some infectious diseases could explain why there is an opposite association between some infectious diseases such as tuberculosis and autoimmune diseases. As a corollary, depletion or inactivation of regulatory T cells could facilitate the development of autoimmune phenomena.

Cloning, overexpression, purification and preliminary crystallographic studies of a mitochondrial type II peroxiredoxin from Pisum sativum.

A cDNA encoding an open reading frame of 199 amino acids corresponding to a type II peroxiredoxin from Pisum sativum with its transit peptide was isolated by RT-PCR. The 171-amino-acid mature protein (estimated molecular weight 18.6 kDa) was cloned into the pET3d vector and overexpressed in Escherichia coli. The recombinant protein was purified and crystallized by the hanging-drop vapour-diffusion technique. A full data set (98.2% completeness) was collected using a rotating-anode generator to a resolution of 2.8 angstroms from a single crystal flash-cooled at 100 K. X-ray data revealed that the protein crystallizes in space group P1, with unit-cell parameters a = 61.88, b = 66.40, c = 77.23 angstroms, alpha = 102.90, beta = 104.40, gamma = 99.07 degrees, and molecular replacement using a theoretical model predicted from the primary structure as a search model confirmed the presence of six molecules in the unit cell as expected from the Matthews coefficient. Refinement of the structure is in progress.