Search

Iron overload caused by hereditary hemochromatosis (HH) increases free reactive oxygen species that, in turn, induce lipid peroxidation. Its 4-hydroxynonenal (HNE) by-product is a well-established marker of lipid peroxidation since it reacts with accessible proteins with deleterious consequences. Indeed, elevated levels of HNE are often detected in a wide variety of human diseases related to oxidative stress. Here, we evaluated HNE-modified proteins in the membrane of erythrocytes from HH patients and in organs of Hfe−/− male and female mice, a mouse model of HH. For this purpose, we used one- and two-dimensional gel electrophoresis, immunoblotting and MALDI-TOF/TOF analysis. We identified cytoskeletal membrane proteins and membrane receptors of erythrocytes bound to HNE exclusively in HH patients. Furthermore, kidney and brain of Hfe−/− mice contained more HNE-adducted protein than healthy controls. Our results identified main HNE-modified proteins suggesting that HH favours preferred protein targets for oxidation by HNE.

The modulation of the host’s metabolism to protect tissue from damage induces tolerance to infections increasing survival. Here, we examined the role of the thyroid hormones, key metabolic regulators, in the outcome of malaria. Hypothyroidism confers protection to experimental cerebral malaria by a disease tolerance mechanism. Hypothyroid mice display increased survival after infection with Plasmodium berghei ANKA, diminishing intracranial pressure and brain damage, without altering pathogen burden, blood-brain barrier disruption, or immune cell infiltration. This protection is reversed by treatment with a Sirtuin 1 inhibitor, while treatment of euthyroid mice with a Sirtuin 1 activator induces tolerance and reduces intracranial pressure and lethality. This indicates that thyroid hormones and Sirtuin 1 are previously unknown targets for cerebral malaria treatment, a major killer of children in endemic malaria areas., This work was funded by grants SAF2017-83289-R to S.A. and A.A., SAF2017-90604REDT to A.A. supported by the The European Regional Development Fund (FEDER) and BIO2016-77430-R to J.M.B. from the Ministerio de Economía y Competitividad; B2017/BMD-3724 to S.A. and A.A. from the Comunidad de Madrid; and CIBERONC CB/16/00228 to A.A. from the Instituto de Salud Carlos III.

The authors have requested that this preprint be removed from Research Square.

After a century of constant failure to produce an in vitro culture of the most widespread human malaria parasite Plasmodium vivax, recent advances have highlighted the difficulties to provide this parasite with a healthy host cell to invade, develop, and multiply under in vitro conditions. The actual level of understanding of the heterogeneous populations of cells—framed under the name ‘reticulocytes’—and, importantly, their adequate in vitro progression from very immature reticulocytes to normocytes (mature erythrocytes) is far from complete. The volatility of its individual stability may suggest the reticulocyte as a delusory cell, particularly to be used for stable culture purposes. Yet, the recent relevance gained by a specific subset of highly immature reticulocytes has brought some hope. Very immature reticulocytes are characterized by a peculiar membrane harboring a plethora of molecules potentially involved in P. vivax invasion and by an intracellular complexity dynamically changing upon its quick maturation into normocytes. We analyze the potentialities offered by this youngest reticulocyte subsets as an ideal in vitro host cell for P. vivax.

Incomplete non-sterile immunity to malaria is attained in endemic regions after recurrent infections by a large percentage of the adult population, who carry the malaria parasite asymptomatically. Although blood-stagePlasmodium falciparumrapidly elicits IgG responses, the target antigens of partially protective and non-protective IgG antibodies as well as the basis for the acquisition of these antibodies remain largely unknown. We performed IgG-immunomics to screen forP. falciparumantigens and to identify epitopes associated with exposure and clinical disease. Sera from malaria cases identified five prevalent antigens recognized by all analyzed patients’ IgGs. For further epitope mapping, peptide microarrays designed to cover their sequences were probed with a set of 38 sera samples from adult individuals of an endemic malaria region in Ghana. Eight 20-mer peptides with the highest affinity and frequency of recognition among the population were subsequently validated with 16 sera from the same region, segregated into patients with positive or negative subclinical detection ofP. falciparum. Significant binding specificity for two immunodominant antigenic regions was uncovered within the START-related lipid transfer protein and the protein disulfide isomerase PDI8. These 20-mer peptides challenged with sera samples from children under 5 years old displayed specific IgG binding in those with detectable parasitemia, even at subclinical level. These results suggest that the humoral response against START and PDI8 antigens may be triggered even at submicroscopic parasitemia levels in children and may eventually be used to differentially diagnose subclinical malaria in children.SignificanceMalaria in Africa is a leading cause of morbidity and mortality. The reservoirs of the malaria parasite are asymptomatic patients who carry it subclinically. Identifying the parasite antigens and its fragments that trigger the most common immunity response by immunoglobulin G that partially protect people can have profound implications for both, development of a malaria vaccine and diagnosis of the subclinical parasite carriers. Antigen discovery and mapping, validated with sera from subclinical carriers, showed that immunoglobulin G responses in children against parasite’s START and PDI8 may eventually be used to differentially diagnose non-infected from subclinical cases. Furthermore, anti-START and anti-PDI8 endemic immunodominance provides association of these antigens with long-term acquired immunity and immune evasion to malaria.

Within the pathophysiology of epilepsy, as a chronic brain disorder, the involvement of neuroinflammation has been extensively implied. Recurrent seizures of epilepsy have been associated with elevated levels of immune mediators that seem to play a pivotal role in triggering them. Neurons, glia, and endothelial cells of the blood-brain barrier (BBB) take part in such inflammatory processes by expressing receptors of associated mediators through autocrine and paracrine stimulation of intracellular signaling pathways. In this milieu, elevated cytokine levels in serum and brain tissue have been reported in patients with an epileptic profile. Noteworthy, interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α) are the proinflammatory cytokines mostly associated, in literature, with the pathogenesis of epilepsies. In this review, we examine the function of these cytokines in connection with transforming growth factor-beta (TGF-β), IL-8, IL-12, IL-18, and macrophage inflammatory protein (MIP) as potential proinflammatory mediators in the neuropathology of epilepsy.

The T helper 17 (Th17) cells contain a dynamic subset of CD4+ T-cells that are able to develop into other different lineage subsets, including the Th1-like Th17 cells. These cells co-express retinoic acid-related orphan receptor gamma t (RORγt) and transcription factor T-box-expressed-in-T-cells (T-bet) and produce both interleukin (IL)-17 and interferon (IFN)-γ. Recent reports have shown that Th1-like Th17 cells play crucial roles in the pathogenesis of autoimmune diseases such as inflammatory bowel disease, multiple sclerosis and rheumatoid arthritis, as well as, some primary immunodeficiency with autoimmune features. Here, the actual mechanisms for Th17 cells plasticity to Th1-like Th17 cells are discussed and reviewed in association to the role that Th1-like Th17 cells have on inflammatory and autoimmune disorders.

A family of dipeptidyl enoates has been prepared and tested against the parasitic cysteine proteases rhodesain, cruzain and falcipain-2 related to sleeping sickness, Chagas disease and malaria, respectively. They have also been tested against human cathepsins B and L1 for selectivity. Dipeptidyl enoates resulted to be irreversible inhibitors of these enzymes. Some of the members of the family are very potent inhibitors of parasitic cysteine proteases displaying k2nd (M−1s−1) values of seven orders of magnitude. In vivo antiprotozoal testing was also performed. Inhibitors exhibited IC50 values in the micromolar range against Plasmodium falciparum, Trypanosoma brucei, Trypanosoma cruzi and even more promising lower values against Leishmania donovanii.

In Plasmodium falciparum the bifunctional enzyme glucose-6-phosphate dehydrogenase‒6-phosphogluconolactonase (PfG6PD‒6PGL) is involved in the catalysis of the first reaction of the pentose phosphate pathway. Since this enzyme has a key role in parasite development, its unique structure represents a potential target for the discovery of antimalarial drugs. Here we describe the first 3D structural model of the G6PD domain of PfG6PD‒6PGL. Compared to the human enzyme (hG6PD), the 3D model has enabled the identification of a key difference in the substrate-binding site, which involves the replacement of Arg365 in hG6PD by Asp750 in PfG6PD. In a prospective validation of the model, this critical change has been exploited to rationally design a novel family of substrate analog-based inhibitors that can display the necessary selectivity towards PfG6PD. A series of glucose derivatives featuring an α-methoxy group at the anomeric position and different side chains at position 6 bearing distinct basic functionalities has been synthesized, and their PfG6PD and hG6PD inhibitory activities and their toxicity against parasite and mammalian cells have been assessed. Several compounds displayed micromolar affinity (Ki up to 23 μM), favorable selectivity (up to > 26-fold), and low cytotoxicity. Phenotypic assays with P. falciparum cultures revealed high micromolar IC50 values, likely as a result of poor internalization of the compounds in the parasite cell. Overall, these results endorse confidence to the 3D model of PfG6PD, paving the way for the use of target-based drug design approaches in antimalarial drug discovery studies around this promising target.

RESUMEN Este estudio presenta la aplicación de las técnicas del Big Data en procesos de enseñanza-aprendizaje musical, mediados por plataformas telemáticas. Se basa en la aplicación de los principios del aprendizaje virtual, la educación personalizada, el uso de Internet y la aplicación de las técnicas del Big Data a partir de la información recogida en sistemas de gestión del conocimiento. En concreto, se plantea la aplicación de dichas técnicas a los test de evaluación inicial, que el alumnado realiza a principio de curso, para medir su nivel de conocimientos previos en la materia. El análisis de la información se efectúa a partir de los datos recogidos en una herramienta para la elaboración de cursos online, Moodle. A partir de dichos datos, se halla un modelo, denominado Bietápico, que permite clasificar los diferentes niveles de conocimientos musicales. Esta técnica posibilita la división de la información en clusters o conglomerados, a través de procesos de análisis programados y automatizados. En definitiva, el modelo bietápico ofrece una manera válida y fiable de gestionar datos masivos en línea en procesos de aprendizaje musical, clasificar la información recogida en las bases de datos y establecer perfiles de alumnado facilitando su monitorización y seguimiento educativos. ABSTRACT This study presents the application of the techniques of Big Data in music teaching and learning processes, using telematic platforms. It is based on the application of the principles of virtual learning, personalized education, Internet using and application of the techniques of Big Data from the information in knowledge management systems. Specifically, the application of such techniques to test initial assessment arises, the students performed in the early going, to measure their level of prior knowledge on the subject. The data analysis is carried out from data collected in a tool for making online courses, Moodle. From these data, a model, called Bietapic model, which classifies the different levels of musical knowledge. This technique allows the division of the information in clusters or conglomerates, through processes programmed and automated analysis. In short, the Bietapic model provides a valid and reliable way to manage massive data online in music learning processes, classify the information collected in databases and profiling of students by facilitating their educational monitoring.

The neurotrophin b-nerve growth factor (NGF) has been described as an important mediator of seminal plasma-induced ovulation in reflexive ovulators like camelids, but this action has not been evidenced in rabbits. In this study, the mRNA expression of NGF was analysed in rabbit male organs by PCR and in a purified basic fraction of seminal plasma by liquid chromatography mass spectrometry. Besides, the ovulatory response [ovulation rate (OR), corpora lutea number, LH peak and progesterone profile] of 27 rabbit does was recorded after injection with murine NGF, gonadoreline (GnRH) or saline solution (SS). An empty catheter was introduced through the vagina (n ¼ 4 animals per group) to simulate the nervous/mechanical stimulus of coitus. Molecular studies confirmed the expression of b-NGF mRNA in the prostate, seminal gland and testicles of male adult rabbits, and the presence of the protein in seminal plasma. For the in vivo experiment, all GnRH-group does exhibited a significantly higher OR (100%) compared to females treated with NGF (30%) and SS (25%), who showed significantly lower LH and progesterone concentrations at 120 min. However, in the non-vaginally stimulated animals, only the gonadoreline group ovulated properly, since no ovulation was recorded in the SS group, and only 17% of the NGF does ovulated; this was associated to a tendency to a higher rate of anovulatory haemorrhagic follicles. mRNA expression of NGF and its presence in seminal plasma evidence a role in rabbit reproduction. Nevertheless, murine NGF triggered some stimulatory effect in the females but not enough to elicit a significant ovulatory response.

Título, resumen y palabras clave en español e inglés Resumen basado en el de la publicación Se aborda cómo la investigación educativa contribuye a cambiar la perspectiva de la enseñanza-aprendizaje. Para ello, se estudia el proceso de adquisición de conocimientos, destrezas y actitudes realizando una aproximación epistemológica al modo en que las personas aprenden y cómo deben adaptarse en función de ello los métodos, los procedimientos y las técnicas didácticas. Se realiza una conceptualización de la inteligencia a tenor de las investigaciones realizadas así como de nuevas formas de enseñanza, aprendizaje basado en el modelo STEM (Science, Technology, Engineering and Mathematics) como forma de integrar estas áreas de aprendizaje de un modo eminentemente práctico centrado en la experiencia de docentes y discentes, desplazando la mera adquisición de conocimientos. Todo ello se enmarca dentro de un proceso de aprendizaje metacognitivo cuya finalidad es que el alumno aprenda a aprender, integrando aspectos como el aprendizaje significativo, la metamemoria, la metacomprensión, la metalectura y la metaescritura. El tipo de aprendizaje y competencias necesarias para el futuro es desconocido por lo que se hace necesaria una reflexividad continua sobre los contenidos y las metodologías de aprendizaje, aspecto que pasa por un cambio curricular y metodológico que tenga presente distintos contextos y modelos de aprendizaje. ESP

La investigación es una pieza importante del funcionamiento de las universidades. La naturaleza de las universidades ha estado unida a la necesidad y la capacidad de investigar desde su nacimiento. Este artículo tiene el objetivo de poner de manifiesto cómo en el contexto actual se plantea la necesidad de investigar en y desde la universidad, aspecto esencial de su liderazgo, en un marco de permanentes contradicciones. Para ello se ha llevado a cabo una revisión documental selectiva y acotada, tras escuchar a informantes clave, acerca de una serie de unidades de significado o categorías: debate sobre la ciencia e investigación científica, modelo por competencias, rol del investigador universitario. Los resultados permiten poner de manifiesto la existencia de un debate sobre los nuevos significados de la ciencia, en un momento de hegemonía del modelo de enseñanza-aprendizaje basado en competencias, donde la función del docente investigador se problematiza., Research is an important part of the functioning of universities. The nature of universities has been linked to the need and capacity for research since their inception. This article aims to show how, in the current context, the need for research in and from the university, an essential aspect of its leadership, is posed in a framework of permanent contradictions. To this end, a selective and limited documentary review has been carried out, after listening to key informants, on a series of units of meaning or categories: debate on science and scientific research, model by competencies, role of the university researcher. The results allow us to highlight the existence of a debate on the new meanings of science, at a time of hegemony of the competence-based teaching-learning model, where the role of the lecturer-researcher is problematized. Keywords: University; research; science; competencies.

This study presents the use of automated data analysis procedures in the teaching-learning process, mediated by telematics platforms. It is based on the application of the principles of virtual learning, the use of the Internet and the automation of data analysis of information collected in Moodle. The application of analysis procedures for the assessment of music competences is proposed based on the data collected in an exam administered at the end of the course. The sample of the study consists of 1327 students (n = 1327) in the first year of Compulsory Secondary Education in Spain and measures the level of acquisition of the key competences denominated “cultural and artistic”. The results are subjected to the K-means classification technique. This technique is used to obtain homogeneously distributed conglomerates which allow for an objective evaluation of the levels of acquisition of the key musical competences.

Control of oxidative stress in the bone marrow (BM) is key for maintaining the interplay between self-renewal, proliferation, and differentiation of hematopoietic cells. Breakdown of this regulation can lead to diseases characterized by BM failure such as the myelodysplastic syndromes (MDS). To better understand the role of oxidative stress in MDS development, we compared protein carbonylation as an indicator of oxidative stress in the BM of patients with MDS and control subjects, and also patients with MDS under treatment with the iron chelator deferasirox (DFX). As expected, differences in the pattern of protein carbonylation were observed in BM samples between MDS patients and controls, with an increase in protein carbonylation in the former. Strikingly, patients under DFX treatment had lower levels of protein carbonylation in BM with respect to untreated patients. Proteomic analysis identified four proteins with high carbonylation levels in MDS BM cells. Finally, as oxidative stress-related signaling pathways can modulate the cell cycle through p53, we analyzed the expression of the p53 target gene p21 in BM cells, finding that it was significantly upregulated in patients with MDS and was significantly downregulated after DFX treatment. Overall, our results suggest that the fine-tuning of oxidative stress levels in the BM of patients with MDS might control malignant progression.

Background:Recent advances in antiviral therapy show potential for a cure and/or control of most human infections caused by hepatitis viruses and retroviruses. However, medical success is largely dependent on the identification of the large number of people unaware of these infections, especially in developing countries. Dried blood spots (DBS) have been demonstrated to be a good tool for collecting, storing and transporting clinical specimens from rural areas and limited-resource settings to laboratory facilities, where viral infections can be more reliably diagnosed.Methods:The seroprevalence and virological characterization of hepatitis B virus (HBV) and hepatitis C virus (HCV), as well as human retroviruses (HIV-1, HIV-2, human T-cell leukaemia virus type 1 [HTLV-1] and human T-cell leukaemia virus type 2 [HTLV-2]), were investigated in clinical specimens collected from DBS in Ghana.Results:A total of 305 consecutive DBS were collected. A high prevalence of chronic HBV (8.5%) and occult hepatitis B (14.2%) was found, whereas rates were lower for HIV-1, HTLV-1 and HCV (3.2%, 1.3% and 0.6%, respectively). HIV-2 and HTLV-2 were absent. CRF02_AG was the predominant HIV-1 subtype, whereas genotype E was the most frequent HBV variant.Conclusions:DBS are helpful in the diagnosis and virological characterization of hepatitis and retrovirus infections in resource-limited settings. The high rate of hepatitis B in Ghana, either overt or occult, is noteworthy and confirms recent findings from other sub-Saharan countries. This should encourage close clinical follow up and antiviral treatment assessment in this population, as well as universal HBV vaccine campaigns.

This paper presents an analysis of the use of an interactive digital whiteboard (IDW) and a computer application called Action Manager (AM), with a sample of 158 sixth-grade students in primary education. Subsequently, a study was carried out with the main goal of testing the didactic functioning of AM and examining the validity of this application, in terms of motivation and the retention of both short and long-term memory when teaching foreign languages in primary education. In order to fulfil these objectives, we performed a positivist exploratory study based on a quantitative methodology combining qualitative aspects (qualitative evaluation) and quantitative aspects (questionnaires) as well as a descriptive method with a survey design. The data collection was performed using instruments, specifically the Extrinsic vs. Intrinsic Orientation Scale, to ascertain the motivational impressions of the students and two memory tests, the Test of Memory and Learning (TOMAL) and the Children&rsquo, s Memory Scale (CMS). Forty-five days later, the two memory tests were repeated to compare the results with the previous ones. After this experience, the results allowed us to conclude that the students demonstrated optimal memorization from a conceptual point of view, in addition to having improved their motivational impressions.

Malaria is a parasitic disease caused by Plasmodium spp., being one of the major causes of death worldwide with two-hundred million new infections and hundreds of thousands of deaths in 2015. Despite the important advances in its prevention and treatment, its resistance to current drug therapies is still a serious risk in its eradication. There is urgency in finding novel targets and drugs operating by novel mechanisms, avoiding cross-resistance to classical antimalarials. In this context, the bifunctional enzyme Glucose-6- phosphate dehydrogenase 6-phosphogluconolactonase appears to be a promising therapeutic target due to its crucial role in regulating the PPP pathway (pentose phosphate pathway), which is the major source of redox potential in Plasmodium falciparum. In the last few years, our group detected a specific mutation between the human and the Plasmodium falciparum form in the binding site of Glucose-6-phosphate (G6P), the endogenous ligand of Glucose-6-phosphate dehydrogenase (G6PD). This mutation involves the substitution of an Arginine (human) by an Aspartate (parasite), which allowed us to create a validated in-house homology model of PfG6PD. Based on this result, the group has focused their efforts, through different molecular modelling techniques, in the discovery of selective scaffolds against PfG6PD. Current efforts address the development of a complete structural model of the bifunctional enzyme, which may offer novel opportunities to develop molecules capable of inhibiting this relevant enzyme.

In some induced-ovulating species, beta nerve growth factor (β-NGF) has important roles in ovulation, though data for rabbits are still inconclusive. In this study we first synthesized functional recombinant β-NGF from rabbit tissue (rrβ-NGF) to address the following objectives: 1) to compare rabbit β-NGF amino acid sequence with those of other induced- or spontaneous-ovulating species; 2) to assess the effects of rrβ-NGF on rabbit sperm viability and motility, and 3) to examine the in vivo ovulation inducing effect of rrβ-NGF added to the seminal dose in rabbit does. The NGF gene in rabbit prostate tissue was sequenced by Rapid Amplification of cDNA Ends and annotated in GenBank (KX528686). Recombinant rβ-NGF was produced in CHO cells and purified by affinity chromatography. Once confirmed by Western blotting and mass spectrometry (MALDI-TOF) that the amino acid sequence of the recombinant protein corresponded to β-NGF, its functionality was validated in PC12 cells in a successful dose-response study over 8 days. The amino acid sequence of prostate rabbit NGF differed to that of other species mainly in its receptor binding sites. In all the spontaneous ovulating species examined, compared with rabbit, alanine and proline residues, which interact with the high-affinity receptor, were replaced by a serine. In rabbits, asparagine and methionine were substituted by lysine at the low-affinity receptor binding site. In time- and dose-response experiments, the in vitro addition of rrβ-NGF to the ejaculate did not affect sperm viability whereas sperm motility parameters were enhanced by the addition of 1 μg/mL of the neuropeptide. Addition of this same concentration of rrβ-NGF to the seminal dose administered via the intravaginal route in does induced ovulation with a delayed LH peak, leading to a plasma progesterone increase, gestation and delivery. Our findings suggest that rrβ-NGF could be a useful option for biotechnological and reproduction assisted techniques in rabbits but further studies are needed.

The neurotrophin β-Nerve Growth Factor (β-NGF) is flourishing as a protein with important roles in the ovulation induction process in induced-ovulation species but data in rabbits are still inconclusive, probably due to the species-specificity effect of the neurotrophin to trigger the ovulation. Moreover, β-NGF seems to have a role in sperm function. To clarify these functionalities we aimed, in the present research: 1) to newly synthesize a functional recombinant β-NGF from rabbit (rrβ-NGF), 2) to reveal differences in the amino acid sequence of rabbit β-NGF compared to other sequences of induced and spontaneous ovulator species, and 3) to assess the effects of rrβ-NGF on sperm viability and motility. The nucleotide sequence of NGF from rabbit prostate was sequenced by Rapid Amplification of cDNA Ends (RACE) and annotated in GenBank (KX528686). Then, rrβ-NGF was produced in CHO cells and purified by affinity chromatography. Western blot and MALDI-TOF analyses confirmed the correct identity of the recombinant protein. rrβ-NGF functionality was validated in PC12 cells through a successful dose-response effect along 8 days. The comparison of the amino acid sequences of NGF between rabbit and other species suggested some relevant substitutions at its binding site to both the high-(TrkA) and the low-(p75) affinity receptors. The addition of rrβ-NGF in rabbit sperm, in a time- and dose-response study, did not affect its viability but slightly changed some of its motility parameters at the highest concentration used (100 ng/ml). Thus, it can be considered that this new recombinant protein may be used for biotechnological and reproduction assisted techniques in ovulation-induced species.

This study reports the gene expression and immunolocalization of the low-affinity neurotrophin receptor, p75, in accessory glands (prostate and bulbourethral glands) and epididymis (caput and cauda) of male rabbits during sexual maturation. We showed that p75 was expressed in all tissues studied with similar mRNA levels during this period. However, it was differentially immunolocalized in bulbourethral glands and stereocilia of epididymis. These findings may be related with some remodeling processes in the accessory glands during sexual maturation, which could be associated with sperm maturation. The interaction of p75 with neurotrophins in rabbit male reproductive tract suggests the possible implication of this system in sexual maturation in rabbits.

β-Nerve Growth Factor (β-NGF) is a neurotrophin which acts through its receptors TrkA and p75, performing important actions in male reproductive physiology and its presence in seminal plasma (SP) has been related to male fertility. The aim of the present study was to evaluate the gene expression profile and the immunolocalization of β-NGF and its high-affinity receptor TrkA in sex organs in rabbits during sexual maturation period. β-NGF concentration for both SP and blood plasma (BP) and BP testosterone levels were determined as well as the seminal parameters during such period. Ten New Zealand White x California young rabbits were trained to semen collection since 20 weeks of age and routinely done once a week with two ejaculations per session. At 22 and 37 weeks of age, semen collection was carried out three times a week and seminal parameters were evaluated. Four males were randomly assigned and slaughtered in each age (n = 8); sex organs (prostate, bulbourethral glands and epididymis) were dissected and collected to determine β-NGF and TrkA gene expression and immunolocalization. SP and BP were also taken at each semen collection session to evaluate β-NGF concentration, and testosterone levels were also assessed in BP. The highest β-NGF mRNA expression was observed in prostate compared to bulbourethral glands and epididymis. These two last tissues showed residual β-NGF mRNA expression and limited localization of the neurotrophin. The prostate epithelial cells and lumen were strongly stained with regard to the other sex organs indicating that immunolocalization of β-NGF rely mainly in the prostate. TrkA gene expression was lower but constant and differentially immunolocalized in the sex organ tissues. Finally, β-NGF concentration in SP and BP remained unchanged in accordance to age, while some seminal characteristics such as sperm concentration, percentage of live sperm and mass and progressive motility were enhanced as endowed by BP testosterone variation. β-NGF and its cognate TrkA receptor are expressed and immunolocalized in the male reproductive tract in the two ages studied, independently of the circulating levels of testosterone and β-NGF.

Quinones are a family of bioactive compounds with known antibacterial, antiviral and antiparasitic activity. The capacity of quinoid compounds to accept electrons, due to electron-attracting (or donating) substituents at the quinone moiety, modulates their redox activity upon interaction with biological systems. Nine quinone derivate including three 2 - hydroxyl - 1, 4 - naphthoquinone; three 4,5 - and three 4,9 - naphthoquinone scaffolds, were synthesized and evaluated against 3D7 and Dd2 Plasmodium falciparum strains and evaluated the oxidative stress. Cell viability was determined MTT-related colorimetric assay (EZ4u; Biomedical, Austria). Selectivity of these compounds was evaluated by comparing in vitro, of cytotoxicity in human fibroblast and antimalarial activity in Plasmodium falciparum. Peripheral blood mononuclear cells and hemoglobin release from human erythrocytes were evaluated too. Antiplasmodial activity was evaluated by fluorometry methods. In addition, oxidized membrane protein in the malaria parasite was evaluated in vitro by derivatization, after treatment at IC50 values on P. falciparum Dd2 strain. Quinones showed IC50 values in the micromole range, selectivity indexes for quinones was variable, compounds 2 and 3 showed excellent selectivity. In vitro antiplasmodial activity was showed; this result is an incentive to continue synthesis and studying the quinoid compounds. Key words: Malaria, Quinones, Plasmodium falciparum.

There currently exists a dire need for safe and inexpensive new antimalarial drugs, which are effective against multiple life cycle stages of Plasmodium falciparum, and act through mechanisms that differ from those of the available drugs to prevent drug resistance. [...]

The co-endemicity of malnutrition, erythrocytopathies, transmissible diseases and iron-deficiency contribute to the prevalence of chronic anaemia in many populations of the developing world. Although iron dietary supplementation is applied or recommended in at risk populations, its use is controversial due to undesirable outcomes, particularly regarding the response to infections, including highly prevalent malaria. We hypothesized that a boosted oxidative stress due to iron supplementation have a similar impact on malaria to that of hereditary anaemias, enhancing innate response and conditioning tissues to prevent damage during infection. Thus, we have analysed antioxidant and innate responses against lethal Plasmodium yoelii during the first five days of infection in an iron-supplemented mouse. This murine model showed high iron concentration in plasma with upregulated expression of hemoxygenase-1. The sustained homeostasis after this extrinsic iron conditioning, delayed parasitemia growth that, once installed, developed without anaemia. This protection was not conferred by the intrinsic iron overload of hereditary hemochromatosis. Upon iron-supplementation, a large increase of the macrophages/dendritic cells ratio and the antigen presenting cells was observed in the mouse spleen, independently of malaria infection. Complementary, malaria promoted the splenic B and T CD4 cells activation. Our results show that the iron supplementation in mice prepares host tissues for oxidative-stress and induces unspecific cellular immune responses, which could be seen as an advantage to promote early defences against malaria infection.

Proteomics is improving malaria research by providing global information on relevant protein sets from the parasite and the host in connection with its cellular structures and specific functions. In the last decade, reports have described biologically significant elements in the proteome of Plasmodium, which are selectively targeted and quantified, allowing for sensitive and high-throughput comparisons. The identification of molecules by which the parasite and the host react during the malaria infection is crucial to the understanding of the underlying pathogenic mechanisms. Hence, proteomics is playing a major role by defining the elements within the pathogenic space between both organisms that change across the parasite life cycle in association with the host transformation and response. Proteomics has identified post-translational modifications in the parasite and the host that are discussed in terms of functional interactions in malaria parasitism. Furthermore, the contribution of proteomics to the investigation of immunogens for potential vaccine candidates is summarized. The malaria-specific technological advances in proteomics are particularly suited now for identifying host-parasite interactions that could lead to promising targets for therapy, diagnosis or prevention. In this review, we examine the knowledge gained on the biology, pathogenesis, immunity and diagnosis of Plasmodium infection from recent proteomic studies. This article is part of a Special Issue entitled: Trends in Microbial Proteomics.

Oxidative stress has been attributed both a key pathogenic and rescuing role in cerebral malaria (CM). In a Plasmodium berghei ANKA murine model of CM, host redox signaling and functioning were examined during the course of neurological damage. Host antioxidant defenses were early altered at the transcriptional level indicated by the gradually diminished expression of superoxide dismutase-1 (sod-1), sod-2, sod-3 and catalase genes. During severe disease, this led to the dysfunctional activity of superoxide dismutase and catalase enzymes in damaged brain regions. Vitagene associated markers (heat shock protein 70 and thioredoxin-1) also showed a decaying expression pattern that paralleled reduced expression of the transcription factors Parkinson disease 7, Forkhead box O 3 and X-box binding protein 1 with a role in preserving brain redox status. However, the oxidative stress markers reactive oxygen/nitrogen species were not accumulated in the brains of CM mice and redox proteomics and immunohistochemistry failed to detect quantitative or qualitative differences in protein carbonylation. Thus, the loss of antioxidant capacity was compensated for in all cerebral regions by progressive upregulation of heme oxygenase-1, and in specific regions by early glutathione peroxidase-1 induction. This study shows for the first time a scenario of cooperative glutathione peroxidase and heme oxygenase-1 upregulation to suppress superoxide dismutase, catalase, heat shock protein-70 and thioredoxin-1 downregulation effects in experimental CM, counteracting oxidative damage and maintaining redox equilibrium. Our findings reconcile the apparent inconsistency between the lack of oxidative metabolite build up and reported protective effect of antioxidant therapy against CM.

The many uses of methylene blue Methylene blue (methylthioninium chloride) is a ‘jack of all trades’ with a litany of clinical uses. In vivo, it is indicated for use as a therapy for drug-induced methemoglobinemia [1-3], can be used for the treatment of infections, pathologies, or poisoning, and as a dye for diagnostics. It is also commonly used as a dye in vitro – for example, as a component in staining of cells, tissues, DNA, parasites, and bacteria [4-6]. In the 1890s, Ehrlich demonstrated its use to target the malarial parasite, and more recently it has been reinvestigated for inclusion in antimalarial regimens in the wake of parasite drug resistance [7-9]. Further examples of its clinical use include treatment of ifosfamide-induced neurotoxicity (although treatment has been reported ineffective), an antidote for cyanide poisoning, visualization of fallopian tubes or ruptured membranes, a marker of tumors, and even as a potential therapy for septic shock and ischemic brain injury [5,8,10-18]. In phase II clinical trials, a modified version of methylene blue is reported to slow cognitive decline in mild–moderate Alzheimer’s disease patients compared to placebo, and phase III trials are planned, although these results remain unpublished [19]. The mechanism of action is unclear – possibly by preventing tau protein aggregation or increasing amyloid-β clearance by enhancing proteasome activities [19,20]. As a photodynamic therapy, methylene blue could be used to treat psoriasis, West Nile virus infection, AIDS-related Kaposi’s sarcoma, antibiotic-resistant bacterial strains and decontaminate blood before transfusion [5,21-25]. Methylene blue has also contributed to drug development, forming the structural chemical basis of other therapeutic drugs, including the antimalarial drug, chloroquine; the antihistamine, promethazine; and the antipsychotic, chlorpromazine [5]. Acknowledging the many uses of methylene blue, this article focuses on the pharmacodynamics of methylene blue in the context of methemoglobinemia treatment and the pathways surrounding this, due to known pharmacogenetic associations that relate to these pathways.

Background and Purpose Blood-stage Plasmodium parasites cause morbidity and mortality from malaria. Parasite resistance to drugs makes development of new chemotherapies an urgency. Aminoacyl-tRNA synthetases have been validated as antimalarial drug targets. We explored long-term effects of borrelidin and mupirocin in lethal P. yoelii murine malaria. Experimental Approach Long-term (up to 340 days) immunological responses to borrelidin or mupirocin were measured after an initial 4 day suppressive test. Prophylaxis and cure were evaluated and the inhibitory effect on the parasites analysed. Key Results Borrelidin protected against lethal malaria at 0.25 mg·kg−1·day−1. Antimalarial activity of borrelidin correlated with accumulation of trophozoites in peripheral blood. All infected mice treated with borrelidin survived and subsequently developed immunity protecting them from re-infection on further challenges, 75 and 340 days after the initial infection. This long-term immunity in borrelidin-treated mice resulted in negligible parasitaemia after re-infections and marked increases in total serum levels of antiparasite IgGs with augmented avidity. Long-term memory IgGs mainly reacted against high and low molecular weight parasite antigens. Immunofluorescence microscopy showed that circulating IgGs bound predominantly to late intracellular stage parasites, mainly schizonts. Conclusions and Implications Low borrelidin doses protected mice from lethal malaria infections and induced protective immune responses after treatment. Development of combination therapies with borrelidin and selective modifications of the borrelidin molecule to specifically inhibit plasmodial threonyl tRNA synthetase should improve therapeutic strategies for malaria.