A GDPase/UDPase bifunctional enzyme from Candida albicans: purification and biochemical characterization.

The most frequently isolated human fungal pathogen is Candida albicans which is responsible for about 50% of all Candida infections. In healthy individuals, this organism resides as a part of the normal microbiota in equilibrium with the host. However, under certain conditions, particularly in immunocompromised patients, this opportunistic pathogen adheres to host cells causing serious systemic infections. Thus, much effort has been dedicated to the study of its physiology with emphasis on factors associated to pathogenicity. A representative analysis deals with the mechanisms of glycoprotein assembly as many cell surface antigens and other macromolecules that modulate the immune system fall within this chemical category. In this regard, studies of the terminal protein glycosylation stage which occurs in Golgi vesicles has led to the identification of nucleotidases that convert glycosyltransferase-generated dinucleotides into the corresponding mononucleotides, thus playing a double function: their activity prevent inhibition of further glycosyl transfer by the accumulation of dinucleotides and the resulting mononucleotides are exchanged by specific membrane transporters for equimolecular amounts of sugar donors from the cytosol. Here, using a simple protocol for protein separation we isolated a bifunctional nucleotidase from C. albicans active on GDP and UDP that was characterized in terms of its molecular mass, response to bivalent ions and other factors, substrate specificity and affinity. Results are discussed in terms of the similarities and differences of this nucleotidase with similar counterparts from other organisms thus contributing to the knowledge of a bifunctional diphosphatase not described before in C. albicans.

Structural relaxation, dynamical arrest, and aging in soft-sphere liquids.

We investigate the structural relaxation of a soft-sphere liquid quenched isochorically (ϕ = 0.7) and instantaneously to different temperatures Tf above and below the glass transition. For this, we combine extensive Brownian dynamics simulations and theoretical calculations based on the non-equilibrium self-consistent generalized Langevin equation (NE-SCGLE) theory. The response of the liquid to a quench generally consists of a sub-linear increase of the α-relaxation time with system's age. Approaching the ideal glass-transition temperature from above (Tf > Ta), sub-aging appears as a transient process describing a broad equilibration crossover for quenches to nearly arrested states. This allows us to empirically determine an equilibration timescale teq(Tf) that becomes increasingly longer as Tf approaches Ta. For quenches inside the glass (Tf ≤ Ta), the growth rate of the structural relaxation time becomes progressively larger as Tf decreases and, unlike the equilibration scenario, τα remains evolving within the whole observation time-window. These features are consistently found in theory and simulations with remarkable semi-quantitative agreement and coincide with those revealed in a previous and complementary study [P. Mendoza-Méndez et al., Phys. Rev. 96, 022608 (2017)] that considered a sequence of quenches with fixed final temperature Tf = 0 but increasing ϕ toward the hard-sphere dynamical arrest volume fraction ϕHS a=0.582. The NE-SCGLE analysis, however, unveils various fundamental aspects of the glass transition, involving the abrupt passage from the ordinary equilibration scenario to the persistent aging effects that are characteristic of glass-forming liquids. The theory also explains that, within the time window of any experimental observation, this can only be observed as a continuous crossover.

Magnetic viscoelastic behavior in a colloidal ferrofluid.

Based on the stochastic Langevin equation, we derived the total friction experienced by a tracer particle diffusing in thermally equilibrated colloidal magnetic fluids. This transport property leads to new expressions for its long-time diffusion coefficients, which satisfy an Einstein relation with the frictions of its translational and rotational Brownian motion. Further use of the nano-rheology theory allowed us to derive also the viscoelastic modulus of the colloid from such a property. The temporal relaxation of the viscoelasticity and transport coefficient turns out to be governed by the intermediate scattering function of the colloid. We derived an explicit formula for this evolution function within a hydrodynamic theory to include rotational degrees of freedom of the particles. In the limit of short frequencies, the viscous moduli render a new expression for the static viscosity. We found that its comparison with known experiments, at low and high concentration of ferroparticles in magnetite ferrofluids, is fair. However, comparing the predicted viscoelastic moduli with computer simulations as a function of frequency yields poor agreement.

Electrohysterogram for ANN-Based Prediction of Imminent Labor in Women with Threatened Preterm Labor Undergoing Tocolytic Therapy.

Threatened preterm labor (TPL) is the most common cause of hospitalization in the second half of pregnancy and entails high costs for health systems. Currently, no reliable labor proximity prediction techniques are available for clinical use. Regular checks by uterine electrohysterogram (EHG) for predicting preterm labor have been widely studied. The aim of the present study was to assess the feasibility of predicting labor with a 7- and 14-day time horizon in TPL women, who may be under tocolytic treatment, using EHG and/or obstetric data. Based on 140 EHG recordings, artificial neural networks were used to develop prediction models. Non-linear EHG parameters were found to be more reliable than linear for differentiating labor in under and over 7/14 days. Using EHG and obstetric data, the <7- and <14-day labor prediction models achieved an AUC in the test group of 87.1 ± 4.3% and 76.2 ± 5.8%, respectively. These results suggest that EHG can be reliable for predicting imminent labor in TPL women, regardless of the tocolytic therapy stage. This paves the way for the development of diagnostic tools to help obstetricians make better decisions on treatments, hospital stays and admitting TPL women, and can therefore reduce costs and improve maternal and fetal wellbeing.

Optimized germinated soybean/cornstarch extrudate and its in vitro fermentation with human inoculum.

The aim of this work was to optimise a soybean/cornstarch extrudate by adjusting a central composite design and to maximise a product with a high protein and resistant starch (RS) content by evaluating the indigestible fractions through in vitro colonic fermentation and production of short-chain fatty acids (SCFAs) with potential health benefits. According to the response surface analysis and RS maximisation results, an optimisation of the independent variables was obtained as follows: 32.5% feed moisture, 144 °C extrusion temperature and a proportion of 44% germinated soybean flour and 56% cornstarch. A product with a 2.11% expansion index, 6.25 N hardness, a glycaemic index of 49 and 12% resistant starch was obtained. The optimised extrudate showed a 36% indigestible fraction and high fermentability with respect to that of the lactulose control. Furthermore, the decrease in pH was inversely proportional to the production of SCFAs and the volume of gas generated. Acetic, propionic, and butyric acids were produced at a molar ratio of 62:27:11, while the highest SCFA concentrations were found 48 h after incubation. The RS of the optimised extruder was a viable substrate for in vitro colonic fermentation, suggesting that it is a good food source to produce SCFAs, which could exert an effect on the regulation of lipid and glucose metabolism.

Regulation of lactate dehydrogenase in response to WSSV infection in the shrimp Litopenaeus vannamei.

Lactate dehydrogenase (LDH) is key for anaerobic glycolysis. LDH is induced by the hypoxia inducible factor -1 (HIF-1). HIF-1 induces genes involved in glucose metabolism and regulates cellular oxygen homeostasis. HIF-1 is formed by a regulatory α-subunit (HIF-1α) and a constitutive ß-subunit (HIF-1ß). The white spot syndrome virus (WSSV) induces anaerobic glycolysis in shrimp hemocytes, associated with lactate accumulation. Although infection and lactate production are associated, the LDH role in WSSV-infected shrimp has not been examined. In this work, the effects of HIF-1 silencing on the expression of two LDH subunits (LDHvan-1 and LDHvan-2) in shrimp infected with the WSSV were studied. HIF-1α transcripts increased in gills, hepatopancreas, and muscle after WSSV infection, while HIF-1ß remained constitutively expressed. The expression for both LDH subunits increased in each tissue evaluated during the WSSV infection, translating into increased enzyme activity. Glucose concentration increased in each tissue evaluated, while lactate increased in gills and hepatopancreas, but not in muscle. Silencing of HIF-1α blocked the increase of LDH expression and enzyme activity, along with glucose (all tissues) and lactate (gills and hepatopancreas) concentrations produced by WSSV infection. These results demonstrate that HIF-1 up regulates the expression of LDH subunits during WSSV infection, and that this induction contributes to substrate metabolism in energetically active tissues of infected shrimp.

Simvastatin exerts antiproliferative and differentiating effects on MG63 osteoblast-like cells: Morphological and immunocytochemical study.

BACKGROUND AND OBJECTIVE: Current evidence suggests that statins exert an anabolic effect on bone and may therefore impact on osteogenic differentiation and proliferation. These effects can be useful for their use in guided bone regeneration. The objective of this study was to determine the in vitro effects of simvastatin on the differentiation and proliferation of MG63 human osteoblast tumor cells. MATERIAL AND METHODS: MG63 human osteosarcoma cells were cultured in the presence of simvastatin or solvent alone for 72 hours, and their proliferation was assessed by MTT assay. Cells from the culture were prepared for light, transmission and scanning electron microscopy studies. immunocytochemical was used to analyze the differentiation and proliferation markers Musashi-1, Ki-67, CD56 and CD44. RESULTS: Cultured MG63 control cells showed spheroid morphology with numerous secretion vesicles accumulated on the surface, observing no cytoplasmic projections with intercellular connections. However, cells cultured with simvastatin had a polygonal and spindle-shaped morphology, with cytoplasmic projections that interconnected cells. There were numerous microvilli-like filamentous projections on the surface with no defined pattern. At 72 hours of culture, CD56, Ki-67 and Musashi-1 expression was significantly reduced (P < .001) in simvastatin-treated cells. CD44 expression was intense in both groups and was not affected by simvastatin treatment. CONCLUSION: MG63 cells cultured with simvastatin for 72 hours undergo morphological and surface changes. Simvastatin treatment exerts antiproliferative and differentiating effects on these cells as well as promoting recovery of cellular homeostasis.

Characterization of Leaf Rust and Stripe Rust Resistance in Spring Wheat 'Chilero'.

Since 1984, the 'Chilero' spring wheat line developed by CIMMYT has proven to be highly resistant to leaf rust and stripe rust. Amid efforts to understand the basis of resistance of this line, a recombinant inbred line (RIL) population derived from a cross between Avocet and Chilero was studied. The parents and RILs were characterized in field trials for leaf rust and stripe rust in three locations in Mexico between 2012 and 2015 and genotyped with DArT-array, DArT-GBS, and SSR markers. A total of 6,168 polymorphic markers were used to construct genetic linkage maps. Inclusive composite interval mapping detected four colocated resistance loci to both rust diseases and two stripe rust resistant loci in the Avocet × Chilero population. Among these, the quantitative trait locus (QTL) on chromosome 1BL was identified as a pleotropic adult plant resistance gene Lr46/Yr29, whereas QLr.cim-5DS/QYr.cim-5DS was a newly discovered colocated resistance locus to both rust diseases in Chilero. Additionally, one new stripe rust resistance locus on chromosome 7BL was mapped in the current population. Avocet also contributed two minor colocated resistance QTLs situated on chromosomes 1DL and 4BS. The flanking SNP markers can be converted to breeder friendly Kompetitive Allele Specific PCR (KASP) markers for wheat breeding programs.

[Long-term results of the early endoscopic treatment of acquired tracheal-subglottic stenosis: 10 years of experience]. / Resultados a largo plazo del tratamiento endoscópico precoz de las estenosis subglóticas y traqueales adquiridas: 10 años de experiencia.

INTRODUCTION: Acquired stenosis of the airway is a common complication after endotracheal intubation. Endoscopic dilation has been accepted as the treatment of choice in cases detected precociously. Our goal is to know the current status of the patients treated in our hospital with endoscopic dilation in the last 10 years. MATERIAL AND METHODS: Retrospective cohort study of patients with subglottic and tracheal acquired stenosis (STAS) early treated endoscopically with balloon dilation at our center in the last 10 years. Bronchoscopy control at 2 weeks, a month, 3 and 6 months post-dilation were performed and later on depending on the symptoms. RESULTS: 32 patient were treated in the period considered. The median age was 4.5 (3-120) months. There were necessary 2.5 (1-5) dilations per patient. All cases were extubated in the operating room or in the following 24 hours. There were no complications during the procedure. Follow-up time was 6 (1-10) years. Only 1 of the 32 patients have had recurrence of stenosis 2 years after, it was secondary to reintubations due to new surgical interventions; which it was dilated successfully. CONCLUSIONS: Early endoscopic dilation in the acquired airway stenosis is a safe and effective long-term procedure. The results support the use of this technique as a treatment of choice in these patients.

INTRODUCCION: La estenosis adquirida de la vía aérea es una complicación frecuente tras la intubación endotraqueal. La dilatación endoscópica ha sido aceptada como tratamiento de elección en los casos detectados de forma precoz. Nuestro objetivo es conocer el estado actual de los pacientes tratados en nuestro centro mediante dilatación endoscópica en los últimos 10 años. MATERIAL Y METODOS: Estudio de cohorte retrospectivo de pacientes con estenosis subglóticas y traqueales adquiridas (ESTA) tratadas endoscópicamente mediante dilatación con balón en nuestro centro en los últimos 10 años. Se realizaron broncoscopias de control a las 2 semanas, al mes, a los 3 y 6 meses postdilatación y posteriormente en función de la clínica. RESULTADOS: Se trataron 32 pacientes de ESTA de reciente aparición en dicho periodo. La mediana de edad fue de 4,5 (3-120) meses. Fueron necesarias 2,5 (1-5) dilataciones por paciente. Todos los pacientes fueron extubados en quirófano o en las 24 horas siguientes al procedimiento. No hubo complicaciones durante los procedimientos ni durante el postoperatorio. El tiempo de seguimiento fue de 6 (1-10) años. Solo 1 de los 32 pacientes presentó recidiva de la estenosis 2 años después que fue secundaria a reintubaciones por nuevas intervenciones quirúrgicas; la cual se dilató nuevamente. CONCLUSIONES: La dilatación endoscópica precoz en las estenosis adquiridas de la vía aérea es un procedimiento seguro y eficaz a largo plazo. Los resultados avalan el uso de esta técnica como tratamiento de elección en estos pacientes.

Molecular aggregation of naphthalimide organic semiconductors assisted by amphiphilic and lipophilic interactions: a joint theoretical and experimental study.

Amphiphilic and lipophilic donor-acceptor naphthalimide-oligothiophene assemblies exhibiting almost identical intramolecular properties, but differing in their intermolecular interactions, have been synthesized. Here we analyze the effect of replacing the normally used lipophilic alkyl chains with hydrophilic ones in directing molecular aggregation from an antiparallel to a parallel stacking. This different molecular packing of the amphiphilic, NIP-3TAmphi, and lipophilic, NIP-3TLipo, systems is assessed by electronic spectroscopies, scanning electronic microscopy and DFT quantum-chemical calculations. Theoretical calculations indicate that the presence of amphiphilic interactions promotes a face-to-face parallel arrangement of neighbor molecules, which induces improved electronic coupling and therefore enhances the charge transport ability and photoconducting properties of this type of materials. Time of flight and photoconducting measurements are used to determine the impact of the amphiphilic and lipophilic interactions on their possible performance in optoelectronic devices.