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Rape followed by murder against children and adolescents is one of the most serious existing crimes. The autopsies of victims of violent crimes can provide fundamental findings for the investigative process and the pursuit of justice. This research conducts a descriptive analysis of the most important findings from the autopsies of 27 cases of children and adolescents who died in Chile between 1998 and 2021 as a result of rape followed by homicide (n = 27), as well as from the judiciary rulings of these cases to gather information related to the perpetrators. It was found that the victims of this crime are mostly girls with an average age of 10, while the perpetrators are primarily single men aged 29 on average, most of whom have not finished high school. A significant relationship was found between the location of the crime and the cause of death and signs of sexual contact, the marital status of the perpetrator and the cause of death, the age of the perpetrator and signs of sexual contact, and the relationship between victim and perpetrator and signs of sexual contact. [ABSTRACT FROM AUTHOR]

Androgenetic alopecia is a highly prevalent condition mainly affecting men. This complex trait is related to aging and genetics; however, multiple other factors, for example, lifestyle, are also involved. Despite its prevalence, the underlying biology of androgenetic alopecia remains elusive, and thus advances in its treatment have been hindered. Herein, we review the functional anatomy of hair follicles and the cell signaling events that play a role in follicle cycling. We also discuss the pathology of androgenetic alopecia and the known molecular mechanisms underlying this condition. Additionally, we describe studies comparing the transcriptional differences in hair follicles between balding and non-balding scalp regions. Given the genetic contribution, we also discuss the most significant risk variants found to be associated with androgenetic alopecia. A more comprehensive understanding of this pathology may be generated through using multi-omics approaches. [ABSTRACT FROM AUTHOR]

There is still a long way ahead regarding the COVID-19 pandemic, since emerging waves remain a daunting challenge to the healthcare system. For this reason, the development of new preventive tools and therapeutic strategies to deal with the disease have been necessary, among which serological assays have played a key role in the control of COVID-19 outbreaks and vaccine development. Here, we have developed and evaluated an immunoassay capable of simultaneously detecting multiple IgG antibodies against different SARS-CoV-2 antigens through the use of Bio-PlexTM technology. Additionally, we have analyzed the antibody response in COVID-19 patients with different clinical profiles in Cadiz, Spain. The multiplex immunoassay presented is a high-throughput and robust immune response monitoring tool capable of concurrently detecting anti-S1, anti-NC and anti-RBD IgG antibodies in serum with a very high sensitivity (94.34–97.96%) and specificity (91.84–100%). Therefore, the immunoassay proposed herein may be a useful monitoring tool for individual humoral immunity against SARS-CoV-2, as well as for epidemiological surveillance. In addition, we show the values of antibodies against multiple SARS-CoV-2 antigens and their correlation with the different clinical profiles of unvaccinated COVID-19 patients in Cadiz, Spain, during the first and second waves of the pandemic. [ABSTRACT FROM AUTHOR]

Since, during the Coronavirus disease 19 (COVID-19) pandemic, a large part of the human population has become infected, a rapid and simple diagnostic method has been necessary to detect its causative agent, the Severe Acute Respiratory Syndrome-related Coronavirus-2 (SARS-CoV-2), and control its spread. Thus, in the present study, we developed a colorimetric reverse transcription-loop-mediated isothermal amplification (RT-LAMP) kit that allows the detection of SARS-CoV-2 from nasopharyngeal swab samples without the need for RNA extraction. The kit utilizes three sets of LAMP primers targeting two regions of ORF1ab and one region in the E gene. The results are based on the colorimetric change of hydroxynaphthol blue, which allows visual interpretation without needing an expensive instrument. The kit demonstrated sensitivity to detect between 50 and 100 copies of the viral genome per reaction. The kit was authorized by the National Administration of Drugs, Food and Technology (ANMAT) of Argentina after validation using samples previously analyzed by the gold standard RT-qPCR. The results showed a sensitivity of 90.6% and specificity of 100%, consistent with conventional RT-qPCR. In silico analysis confirmed the recognition of SARS-CoV-2 variants of concern (B.1.1.7, B.1.351, P.1, B.1.617.2, B.1.427, and B.1.429), and lineages of the Omicron variant (B.1.1.529) with 100% homology. This rapid, simple, and sensitive RT-LAMP method paves the way for a large screening strategy to be carried out at locations lacking sophisticated instrumental and trained staff, as it particularly happens in regional hospitals and medical centers from rural areas. [ABSTRACT FROM AUTHOR]

In this work, the synthesis of bimetallic Ag and Cu particles on carbon vulcan (AgCu/C) is reported, synthesized by a simple galvanic displacement method using citrate tribasic hydrate as a co-reducing agent and a commercial material based on Cu/C as a template. The materials were characterized by several physicochemical techniques, including TGA, ICP-OES, XRD, SEM, and BET. The catalysts were evaluated as cathodic catalysts for the oxygen reduction reaction (ORR) and were used for the preparation of membrane electrode assemblies for evaluation in an Anion Exchange Membrane Fuel Cell (AEMFC). The results were compared with the commercial Ag/C and Cu/C catalysts; the bimetallic catalyst obtained a higher power density, which was attributed to a synergistic effect between Ag and Cu particles. [ABSTRACT FROM AUTHOR]

To evaluate the diagnostic value of the combination of two broad‐range PCR assays targeting two different and conserved regions of the viral genome for the diagnosis of acute Hepatitis E virus (HEV) infection. Patients with acute hepatitis were prospectively recruited. In all, HEV‐IgM antibodies were tested together with evaluation of HEV viraemia by two PCR assays (ORF3 and ORF1). The number of individuals exhibiting negative IgM antibody results but carrying viral RNA was calculated by each PCR assay. Four‐hundred and seventy individuals were included, of whom 145 (30.8%) were diagnosed as having acute HEV. Of them, 122 (84.1%) exhibited HEV‐IgM antibodies, and 81 (55.8%) had detectable viral RNA for at least one PCR. Using the ORF3 molecular assay, 70 (48.3%) individuals were identified with HEV infection. When the ORF1 molecular assay was applied, 49 (33.8%) individuals were identified. The ORF3 assay detected viral RNA in 32 patients not detected by the ORF1 assay. In contrast, the ORF1 assay could amplify viral RNA in 11 patients who were not detected by the ORF3 assay. The parallel use of two broad‐range PCR assays significantly increased the performance of the molecular diagnosis of HEV. [ABSTRACT FROM AUTHOR]

Background Neglected tropical diseases (NTDs) disproportionately affect populations living in resource-limited settings. In the Amazon basin, substantial numbers of NTDs are zoonotic, transmitted by vertebrate (dogs, bats, snakes) and invertebrate species (sand flies and triatomine insects). However, no dedicated consortia exist to find commonalities in the risk factors for or mitigations against bite-associated NTDs such as rabies, snake envenoming, Chagas disease and leishmaniasis in the region. The rapid expansion of COVID-19 has further reduced resources for NTDs, exacerbated health inequality and reiterated the need to raise awareness of NTDs related to bites. Methods The nine countries that make up the Amazon basin have been considered (Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Surinam and Venezuela) in the formation of a new network. Results The Amazonian Tropical Bites Research Initiative (ATBRI) has been created, with the aim of creating transdisciplinary solutions to the problem of animal bites leading to disease in Amazonian communities. The ATBRI seeks to unify the currently disjointed approach to the control of bite-related neglected zoonoses across Latin America. Conclusions The coordination of different sectors and inclusion of all stakeholders will advance this field and generate evidence for policy-making, promoting governance and linkage across a One Health arena. [ABSTRACT FROM AUTHOR]

Background: The aim was clinical evaluation of immune response against SARS-CoV-2, analyzing serum levels of IgG antibodies against the SARS-CoV-2 protein S in infected and vaccinated patients, as well as in subjects with and without frequent comorbidities (arterial hypertension, diabetes mellitus, heart disease, and chronic respiratory disease). Methods: Patients infected by SARS-CoV-2 confirmed by RT-PCR and subjects vaccinated with vaccines based on the mRNA encoding the SARS-CoV-2 protein S were studied. SARS-CoV-2 anti-S IgG serum levels were quantified by chemiluminescent microparticle immunoassay. Results: There were 79 infected patients with a median age of 53.0 years; 35 women and 44 men; 42 patients with any comorbidities and 37 without comorbidities. The median of SARS-CoV-2 anti-S IgG serum level was 203.4 BAU/mL (11.6 - 5,620.6). The median antibody level in the infected patients with any comorbidities was higher than those without comorbidities. The group of vaccinated subjects included 96 subjects with a median age of 49.5 years; 77 women and 19 men; 31 subjects with any comorbidities and 65 without comorbidities. The median of SARS-CoV-2 anti-S IgG serum levels was 1,145.6 BAU/mL (138.3 - 4,828.1). No significant differences were found in terms of specific or global comorbidities in the vaccinated subjects. Conclusions: SARS-CoV-2 anti-S IgG serum levels were 5.6 times higher in vaccinated subjects than infected patients. The vaccination produces higher serum antibody levels than SARS-CoV-2 infection. This reinforces the indication for the vaccine in infected patients. These antibodies did not decrease significantly in patients with frequent comorbidities such as hypertension, diabetes, heart disease or chronic respiratory disease. [ABSTRACT FROM AUTHOR]

The increase in the life expectancy of the population forces the discussion about the extension of productive years, the delay in the retirement age and puts at risk the cancellation of enjoyment and rest in old age. In poor and/or peripheral countries, with fragile social security systems, work for the older population is the only form of economic subsistence that makes it possible to maintain the material conditions of life. In this context, they are forced to take precarious forms of formal or informal salaried work that do not provide a decent standard of living. This research analyzed representations and narratives about work in old age that are constructed in the media and social networks in Chile. [ABSTRACT FROM AUTHOR]

Rapid diagnosis by using small, simple, and portable devices could represent one of the best strategies to limit the damage and contain the spread of viral, bacterial or protozoa diseases, principally when they can be transmitted by air and are highly contagious, as some respiratory viruses are. The presence of antibodies in blood or serum samples is not the best option for deciding when a person must be quarantined to stop transmission of disease, given that cured patients have antibodies, so the best diagnosis methods rely on the use of nucleic acid amplification procedures. Here we present a very simple device and detection principle, based a paper discs coupled to contactless conductivity (C4D) sensors, can provide fast and easy diagnostics that are needed when an epidemic outbreak develops. The paper device presented here solves one of the main drawbacks that nucleic acid amplification tests have when they are performed outside of central laboratories. As the device is sealed before amplification and integrally disposed in this way, amplimers release cannot occur, allowing repetitive testing in the physician's practice, ambulances, or other places that are not prepared to avoid cross-contamination of new samples. The use of very low volume samples allows efficient reagent use and the development of low cost, simple, and disposable point-of-care diagnostic systems. Author summary: In 2005, the World Health Organization (WHO) recognized Chagas Disease as a neglected tropical disease. Meanwhile the serological tests, recommended by WHO, can be performed for chronic disease diagnosis, the nucleic acid amplification tests must be performed for the detection of the acute phase of the disease. Although the existing laboratory diagnosis tests for Chagas Disease are sensitive and highly reproducible, they cannot be performed in rural, low infrastructure environments, where this disease prevails. In this sense, the use of simple and portable analytical devices may be able to offer an affordable solution to this problem, allowing fast sampling, diagnosis and treatment prescription in one simple and fast intervention, as the performed by short term medical missions. In this study we show for the first time a diagnosis test comprising low cost materials and employing a contactless and label-free conductivity detection system that is used to read the result of a nucleic acid amplification reaction. The test showed high sensitivity for Chagas Disease diagnosis showing the potential to be used in rural and low income places. [ABSTRACT FROM AUTHOR]

Cruzipain, the major cysteine protease of the pathogenic protozoa Trypanosoma cruzi, is an important virulence factor that plays a key role in the parasite nutrition, differentiation and host cell infection. Cruzipain is synthesized as a zymogen, matured, and delivered to reservosomes. These organelles that store proteins and lipids ingested by endocytosis undergo a dramatic decrease in number during the metacyclogenesis of T. cruzi. Autophagy is a process that digests the own cell components to supply energy under starvation or different stress situations. This pathway is important during cell growth, differentiation and death. Previously, we showed that the autophagy pathway of T. cruzi is induced during metacyclogenesis. This work aimed to evaluate the participation of macroautophagy/autophagy in the distribution and function of reservosomes and cruzipain during this process. We found that parasite starvation promotes the cruzipain delivery to reservosomes. Enhanced autophagy increases acidity and hydrolytic activity in these compartments resulting in cruzipain enzymatic activation and self- processing. Inhibition of autophagy similarly impairs cruzipain traffic and activity than protease inhibitors, whereas mutant parasites that exhibit increased basal autophagy, also display increased cruzipain processing under control conditions. Further experiments showed that autophagy induced cruzipain activation and self-processing promote T. cruzi differentiation and host cell infection. These findings highlight the key role of T. cruzi autophagy in these processes and reveal a potential new target for Chagas disease therapy. Abbreviations: Baf: bafilomycin A1; CTE: C-terminal extension; Cz: cruzipain; IIF: indirect immunofluorescence; K777: vinyl sulfone with specific Cz inhibitory activity; Prot Inh: broad-spectrum protease inhibitor; Spa1: spautin-1; Wort: wortmannin [ABSTRACT FROM AUTHOR]

Copyright of Ciencia e Innovación en Salud is the property of Universidad Simon Bolivar (USB) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Trypanosoma cruzi carbonic anhydrase (TcCA) has recently emerged as an interesting target for the design of new compounds to treat Chagas disease. In this study we report the results of a structure-based virtual screening campaign to identify novel and selective TcCA inhibitors. The combination of properly validated computational methodologies such as comparative modelling, molecular dynamics and docking simulations allowed us to find high potency hits, with KI values in the nanomolar range. The compounds also showed trypanocidal effects against T. cruzi epimastigotes and trypomastigotes. All the candidates are selective for inhibiting TcCA over the human isoform CA II, which is encouraging in terms of possible therapeutic safety and efficacy. [ABSTRACT FROM AUTHOR]

In this work, a sensitive and highly stable non-enzymatic glucose sensor is reported. It is based on self-assembled 3- mercaptophenylboronic acid (3MPBA) self-assembled on small Pt nanoparticles supported on a multi-wall carbon nanotubes (CNTs) surface. The materials characterization was performed by thermal analysis (TGA), scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), cyclic voltammetry (CV), and Z potential measurements. Glucose and fructose evaluation was carried out by hydrodynamic zeta potential measurements using the streaming potential, presenting high selectivity to glucose in the alkaline medium. The 3MPBA-PtNPs-CNTs electrode exhibit a linear response in the glucose concentration range of 0 to 10 mM, high sensitivity to 22.25 mV mM−1, and ultra-low detection of 4.5 μM. [ABSTRACT FROM AUTHOR]

We studied the effect of the organic solvent on the synthesis of platinum nanoparticles anchored on the surface of multi-wall carbon nanotubes (Pt NPs/MWCNT) by the reverse microemulsion method. For oil phase, three organic solvents of the same alkane chain length (six carbon atoms) were tested: hexane, cyclohexane, and 2,2,4-trimethylpentane. The total metallic content was characterized by thermogravimetric analysis (TGA), and Pt NPs were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The chemical structure of the oil phase influences the Pt loading and crystallite size. The catalyst prepared with 2,2,4-trimethylpentane showed the highest electrochemical active surface area, enhancing the mass and specific activity compared to the commercial electrocatalyst (Pt/C) in the methanol oxidation reaction (MOR). [ABSTRACT FROM AUTHOR]

Copyright of Estudios Pedagogicos (Valdivia) is the property of Estudios Pedagogicos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chagas disease is a neglected tropical disease endemic to Latin America, though migratory movements have recently spread it to other regions. Here, we have applied a cascade virtual screening campaign combining ligand- and structure-based methods. In order to find novel inhibitors of putrescine uptake in Trypanosoma cruzi, an ensemble of linear ligand-based classifiers obtained by has been applied as initial screening filter, followed by docking into a homology model of the putrescine permease TcPAT12. 1,000 individual linear classifiers were inferred from a balanced dataset. Subsequently, different schemes were tested to combine the individual classifiers: MIN operator, average ranking, average score, average voting, with MIN operator leading to the best performance. The homology model was based on the arginine/agmatine antiporter (AdiC) from Escherichia coli as template. It showed 64% coverage of the entire query sequence and it was selected based on the normalized Discrete Optimized Protein Energy parameter and the GA341 score. The modeled structure had 96% in the allowed area of Ramachandran's plot, and none of the residues located in non-allowed regions were involved in the active site of the transporter. Positivity Predictive Value surfaces were applied to optimize the score thresholds to be used in the ligand-based virtual screening step: for that purpose Positivity Predictive Value was charted as a function of putative yields of active in the range 0.001–0.010 and the Se/Sp ratio. With a focus on drug repositioning opportunities, DrugBank and Sweetlead databases were subjected to screening. Among 8 hits, cinnarizine, a drug frequently prescribed for motion sickness and balance disorder, was tested against T. cruzi epimastigotes and amastigotes, confirming its trypanocidal effects and its inhibitory effects on putrescine uptake. Furthermore, clofazimine, an antibiotic with already proven trypanocidal effects, also displayed inhibitory effects on putrescine uptake. Two other hits, meclizine and butoconazole, also displayed trypanocidal effects (in the case of meclizine, against both epimastigotes and amastigotes), without inhibiting putrescine uptake. [ABSTRACT FROM AUTHOR]

Autophagy is a cellular process required for the removal of aged organelles and cytosolic components through lysosomal degradation. All types of eukaryotic cells from yeasts to mammalian cells have the machinery to activate autophagy as a result of many physiological and pathological situations. The most frequent stimulus of autophagy is starvation and the result, in this case, is the fast generation of utilizable food (e.g. amino acids and basic nutrients) to maintain the vital biological processes. In some organisms, starvation also triggers other associated processes such as differentiation. The protozoan parasite Trypanosoma cruzi undergoes a series of differentiation processes throughout its complex life cycle. Although not all autophagic genes have been identified in the T. cruzi genome, previous works have demonstrated the presence of essential autophagic-related proteins. Under starvation conditions, TcAtg8, which is the parasite homolog of Atg8/LC3 in other organisms, is located in autophagosome-like vesicles. In this work, we have characterized the autophagic pathway during T. cruzi differentiation from the epimastigote to metacyclic trypomastigote form, a process called metacyclogenesis. We demonstrated that autophagy is stimulated during metacyclogenesis and that the induction of autophagy promotes this process. Moreover, with exception of bafilomycin, other classical autophagy modulators have similar effects on T. cruzi autophagy. We also showed that spermidine and related polyamines can positively regulate parasite autophagy and differentiation. We concluded that both polyamine metabolism and autophagy are key processes during T. cruzi metacyclogenesis that could be exploited as drug targets to avoid the parasite cycle progression. [ABSTRACT FROM AUTHOR]

Background: Trypanosomatid parasites represent a major health issue affecting hundreds of million people worldwide, with clinical treatments that are partially effective and/or very toxic. They are responsible for serious human and plant diseases including Trypanosoma cruzi (Chagas disease), Trypanosoma brucei (Sleeping sickness), Leishmania spp. (Leishmaniasis), and Phytomonas spp. (phytoparasites). Both, animals and trypanosomatids lack the biosynthetic riboflavin (vitamin B2) pathway, the vital precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) cofactors. While metazoans obtain riboflavin from the diet through RFVT/SLC52 transporters, the riboflavin transport mechanisms in trypanosomatids still remain unknown. Methodology/Principal findings: Here, we show that riboflavin is imported with high affinity in Trypanosoma cruzi, Trypanosoma brucei, Leishmania (Leishmania) mexicana, Crithidia fasciculata and Phytomonas Jma using radiolabeled riboflavin transport assays. The vitamin is incorporated through a saturable carrier-mediated process. Effective competitive uptake occurs with riboflavin analogs roseoflavin, lumiflavin and lumichrome, and co-factor derivatives FMN and FAD. Moreover, important biological processes evaluated in T. cruzi (i.e. proliferation, metacyclogenesis and amastigote replication) are dependent on riboflavin availability. In addition, the riboflavin competitive analogs were found to interfere with parasite physiology on riboflavin-dependent processes. By means of bioinformatics analyses we identified a novel family of riboflavin transporters (RibJ) in trypanosomatids. Two RibJ members, TcRibJ and TbRibJ from T. cruzi and T. brucei respectively, were functionally characterized using homologous and/or heterologous expression systems. Conclusions/Significance: The RibJ family represents the first riboflavin transporters found in protists and the third eukaryotic family known to date. The essentiality of riboflavin for trypanosomatids, and the structural/biochemical differences that RFVT/SLC52 and RibJ present, make the riboflavin transporter -and its downstream metabolism- a potential trypanocidal drug target. [ABSTRACT FROM AUTHOR]

Platinum nanoparticles (PtNPs) on multi-wall carbon nanotubes (MWCNT) were functionalized with 4-mercaptophenylboronic acid (4MPB) for electrochemical detection of fructose. The composite nanomaterial was characterized by physicochemical techniques such as TGA and TEM, and electrochemically using the [Fe(CN)6]3-/4- as channel ion. Experimental values indicate that this sensor presents high sensitivity and selectivity for electrochemical detection of fructose with the sensitivity of 2.794 x 10-5 A mM-1 in a range of 2.5 to 10 mM using cyclic voltammetry and sensitivity 8.65 Ω mM-1 in range of 0.5 to 10 mM using electrochemical impedance spectroscopy. [ABSTRACT FROM AUTHOR]

We reported the synthesis of platinum particles anchored on the surface of multiwall carbon nanotubes (MWCNTs). The synthesis of platinum particles was carried out by microemulsion method using hexadecyltrimethylammonium bromide (CTAB) as surfactant to enhance the dispersion of platinum particles in hexane (C6), heptane (C7), and octane (C8) solutions. The effects of the microemulsion dispersion medium on the synthesis of platinum particles on MWCNTs (MWCNT/Pt) hybrid materials and their catalytic activities of the oxygen reduction reaction (ORR) in HClO4 were investigated. The anchored platinum particles showed good dispersion on carbon nanotubes surface with the average particle sizes of 2.65±0.60, 2.89±0.68, and 0.97±0.29 nm for the dispersion medium of C6, C7, and C8, respectively. The experimental results of ORR experiments indicated a relationship between the size and the dispersion media of the platinum particles; also the catalytic activity of the anchored platinum on MWCNT particles strongly depends on the dispersion medium employed in the microemulsion process. [ABSTRACT FROM AUTHOR]

Introduction One of the most researched theories of personality is the Five Factor Model, frequently evaluated through the Big Five Inventory. Even though there is a Spanish version, its psychometrical properties in Mexican population are yet unknown. Methods We evaluated 472 adults (217 male/255 female) from an open population from Mexico City. Results We obtained a total scale reliability score of É‘=0.72. Principal Component Analysis using Velicer's Minimun Average Partial validated a 5 factor structure. We also found differences between subjects that had been diagnosed with a psychiatric or neurological disorder by a health professional in agreeableness, responsability and neuroticism. Conclusions Our results suggest that the Big Five Inventory is useful to evaluate the personality in Mexican population. However, a review of the Agreeableness scale may be needed because its low reliability and poor item loadings. [ABSTRACT FROM AUTHOR]

Chitosan has been studied for use in particle delivery systems for therapeutic purposes, since one of its most important applications is as a non-viral vector in gene therapy. Due to its positive charge, it is capable of forming DNA complexes (polyplexes) obtained through several methods and with the property of protecting nucleic acids. Two methods for obtaining the nanoparticles of chitosan-nucleic acids are reported in this study: simple complexation (of depolymerized chitosan or of different chitosan salts with plasmid) and ionic gelation (by adsorption of plasmid in the nanoparticles or by encapsulation of plasmid into nanoparticles). The determination of the loading efficiency of chitosan nanoparticles with the plasmid is carried out by electrophoretic mobility of the samples on agarose gel. Furthermore, the nanoparticles have been characterized according to their morphology, size and surface charge using AFM, TEM, laser diffraction and dynamic light scattering techniques. The polyplexes obtained have been found to be spherical and nanometric in size (between 100–230 nm) with a zeta potential between 37 and 48 mV. Positive results have been obtained by agarose gel electrophoresis for all studied cases: a concentration of between 20 and 30 μg/mL of chitosan salts is required while for the remaining chitosan samples studied, 100% loading efficiency does not occur until a concentration equal to 100 μg/mL (regardless of previous depolymerisation and the method performed). Chitosan–plasmid nanocapsules have been obtained at the polymer concentrations worked with (between 0.025 and 0.2%). [ABSTRACT FROM AUTHOR]

Abstract: Phytomonas are trypanosomatid plant parasites closely related to parasites that cause several human diseases. Little is known about the biology of these organisms including aspects of their metabolism. Arginine kinase (E.C. 2.7.3.3) is a phosphotransferase which catalyzes the interconversion between the phosphagen phosphoarginine and ATP. This enzyme is present in some invertebrates and is a homolog of another widely distributed phosphosphagen kinase, creatine kinase. In this work, a single canonical arginine kinase isoform was detected in Phytomonas Jma by enzymatic activity assays, PCR, and Western Blot. This arginine kinase is very similar to the canonical isoforms found in T. cruzi and T. brucei, presenting about 70% of amino acid sequence identity and a very similar molecular weight (40kDa). The Phytomonas phosphagen system seems to be very similar to T. cruzi, which has only one isoform, or T. brucei (three isoforms); establishing a difference with other trypanosomatids, such as Leishmania, which completely lacks phosphagen kinases, probably by the presence of the arginine-consuming enzyme, arginase. Finally, phylogenetic analysis suggests that Kinetoplastids'' arginine kinase was acquired, during evolution, from the arthropod vectors by horizontal gene transfer. [Copyright &y& Elsevier]

Polyamines are essential for Trypanosoma cruzi, the causative agent of Chagas disease. As T. cruzi behaves as a natural auxotrophic organism, it relies on host polyamines biosynthesis. In this paper we obtained a double-transfected T. cruzi parasite that expresses the green fluorescent protein (GFP) and a heterologous ornithine decarboxylase (ODC), used itself as a novel selectable marker. These autotrophic and fluorescent parasites were characterized; the ODC presented an apparent Km for ornithine of 0.51 ± 0.16mM and an estimated Vmax value of 476.2 nmoles/h/mg of protein. These expressing ODC parasites showed higher metacyclogenesis capacity than the auxotrophic counterpart, supporting the idea that polyamines are engaged in this process. This double-transfected T. cruzi parasite results in a powerful tool—easy to follow by its fluorescence—to study the role of polyamines in Chagas disease pathology and in related processes such as parasite survival, invasion, proliferation,metacyclogenesis, and tissue spreading. [ABSTRACT FROM AUTHOR]

Trypanosoma cruzi, the aetiological agent of Chagas' disease, is exposed to extremely different environment conditions during its life cycle, and transporters are key molecules for its adaptive regulation. Amino acids, and particularly arginine, are essential components in T. cruzi metabolism. In this work, a novel T. cruzi arginine permease was identified by screening different members of the AAAP family (amino acid/auxin permeases) in yeast complementation assays using a toxic arginine analogue. One gene candidate, TcAAAP411, was characterized as a very specific, high-affinity,l-arginine permease. This work is the first identification of the molecular components involved specifically in amino acid transport in T. cruzi and provides new insights for further validation of the TcAAAP family as functional permeases. [ABSTRACT FROM AUTHOR]

Abstract: Trypanosoma cruzi, the etiologic agent of Chagas'' disease, is a polyamine auxotroph organism because its genome contains neither ornithine decarboxylase (ODC) nor arginine decarboxylase (ADC) genes, presumably lost during evolution. After transformation with a recombinant plasmid bearing the complete coding region of Crithidia fasciculata ODC gene, the transgenic parasites were able to synthesize putrescine and simultaneously became susceptible to α-difluoromethylornithine (DFMO), an irreversible inhibitor of ODC. We have studied the emergence of DFMO-resistant T. cruzi after one-step selection of ODC-transformed parasites cultivated in the presence of high levels of the drug (5 mM). Our results have indicated a duplication of the ODC gene copy number in the drug-resistant cell line. The ODC transcripts and the corresponding translation products showed very significant increases (about 7- and 25-fold, respectively) in DFMO-resistant parasites, while the ODC enzymatic activity was 5 times higher than in drug-sensitive T. cruzi. The unequal increases of ODC protein and enzymatic activity in DFMO-resistant protozoa strongly suggest that in addition to gene amplification and enhanced transcription and translation, the assembly of ODC polypeptide chains into dimeric active enzyme molecules might also contribute to regulate the development of DFMO resistance. [Copyright &y& Elsevier]

Abstract: Phytomonas cells (Phytomonas Jma) isolated from the latex of Jatropha macrantha were assayed for amino acid, hexose and polyamine transport. Results showed high transport rates for glucose and fructose (193 and 128pmolmin−1 10−7 cells, respectively) and lower, but significant rates, for proline, arginine, cysteine and glutamate (between 1.7 and 5.8pmolmin−1 10−7 cells). Minor transport activities were observed for serine, glycine and aspartate (<1pmolmin−1 10−7 cells). Amino acid transport processes do not seem to be regulated by starvation or during the growth phases. Polyamine transport was also evaluated showing a clear preference for spermidine over putrescine (3.4 and 0.4 pmolmin−1 10−7 cells, respectively). This work represents the first report on metabolite transport in phytomonads. [Copyright &y& Elsevier]