Enzymatic variability among Brazilian Pythium insidiosum isolates

BackgroundPythium insidiosum is an oomycete classified in the kingdom Stramenopila. P. insidiosum hyphae are not able to initiate infection without the secretion of hydrolytic enzymes, which are considered an important factor in microbial virulence.AimsTo evaluate the extracellular enzymatic activity of 14 Brazilian P. insidiosum isolates and a standard strain (ATCC 58637) by the API-ZYM System screening method.MethodsZoospores were grown in RPMI 1640 broth, and 65 μL of the liquid phase were inoculated in each cupule of the API-ZYM strips.ResultsDifferences in the enzymatic activities were observed among the isolates, although phosphohydrolases and ester hydrolases were conspicuous among all isolates. β-glucosidase was also present in most of the isolates. Enzymatic activities of α-glucosidase and chymotrypsin were not observed, differing from a previous study involving Australian isolates and intracellular enzymes.ConclusionsThe discrepancy in the enzymatic profile observed among Brazilian P. insidiosum isolates reflects the phenotypic variations found in susceptibility tests.     

The immunogenicity to the first anti-TNF therapy determines the outcome of switching to a second anti-TNF therapy in spondyloarthritis patients

Introduction

Anti-TNF drugs have proven to be effective against spondyloarthritis (SpA), although 30% of patients fail to respond or experience adverse events leading to treatment discontinuation. In rheumatoid arthritis, the presence of anti-drug antibodies (ADA) against the first TNF inhibitor influences the outcome after switching. Our aim was to assess whether the response to a second anti-TNF drug is related to the previous development of ADA to the first anti-TNF drug SpA patients.

Methods

Forty-two SpA patients began a second anti-TNF drug after failing to respond to the first anti-TNF therapy. Clinical activity was assessed by the Ankylosing Spondylitis Disease Activity Score (ASDAS) at baseline (at the beginning of the first and second anti-TNF therapy) and at 6 months after switching. The drug and ADA levels were measured by ELISA before each administration.

Results

All patients were treated with anti-TNF drugs and mainly due to inefficacy were switched to a second anti-TNF drug. Eleven of 42 (26.2%) developed ADA during the first biologic treatment. At baseline, no differences in ASDAS were found in patients with or without ADA to the first anti-TNF drug (3.52 ± 1.03 without ADA vs. 3.14 ± 0.95 with ADA, p = 0.399) and to the second anti-TNF drug (3.36 ± 0.94 without ADA vs. 3.09 ± 0.91 with ADA, p = 0.466). At 6 months after switching, patients with previous ADA had lower disease activity (1.62 ± 0.93 with ADA vs. 2.79 ± 1.01 without ADA, p = 0.002) and most patients without ADA had high disease activity state by the ASDAS (25 out of 31 (80.6%) without ADA vs. 3 out of 11 (27.3%) with ADA, p = 0.002).

Conclusions

In SpA the failure to respond to the first anti-TNF drug due to the presence of ADA predicts a better clinical response to a second anti-TNF drug.     

Eco-Bio-Social Determinants for House Infestation by Non-domiciliated Triatoma dimidiata in the Yucatan Peninsula,Mexico

Background

Chagas disease is a vector-borne disease of major importance in the Americas. Disease prevention is mostly limited to vector control. Integrated interventions targeting ecological, biological and social determinants of vector-borne diseases are increasingly used for improved control.

Methodology/principal findings

We investigated key factors associated with transient house infestation by T. dimidiata in rural villages in Yucatan, Mexico, using a mixed modeling approach based on initial null-hypothesis testing followed by multimodel inference and averaging on data from 308 houses from three villages. We found that the presence of dogs, chickens and potential refuges, such as rock piles, in the peridomicile as well as the proximity of houses to vegetation at the periphery of the village and to public light sources are major risk factors for infestation. These factors explain most of the intra-village variations in infestation.

Conclusions/significance

These results underline a process of infestation distinct from that of domiciliated triatomines and may be used for risk stratification of houses for both vector surveillance and control. Combined integrated vector interventions, informed by an Ecohealth perspective, should aim at targeting several of these factors to effectively reduce infestation and provide sustainable vector control.     

C2ORF40 suppresses breast cancer cell proliferation and invasion through modulating expression of M phase cell cycle genes

Recently, it has been suggested that C2ORF40 is a candidate tumor suppressor gene in breast cancer. However, the mechanism for reduced expression of C2ORF40 and its functional role in breast cancers remain unclear. Here we show that C2ORF40 is frequently silenced in human primary breast cancers and cell lines through promoter hypermethylation. C2ORF40 mRNA level is significantly associated with patient disease-free survival and distant cancer metastasis. Overexpression of C2ORF40 inhibits breast cancer cell proliferation, migration and invasion. By contrast, silencing C2ORF40 expression promotes these biological phenotypes. Bioinformatics and FACS analysis reveal C2ORF40 functions at G2/M phase by downregulation of mitotic genes expression, including UBE2C. Our results suggest that C2ORF40 acts as a tumor suppressor gene in breast cancer pathogenesis and progression and is a candidate prognostic marker for this disease.     

Fine Mapping and Functional Analysis of the Multiple Sclerosis Risk Gene CD6

CD6 has recently been identified and validated as risk gene for multiple sclerosis (MS), based on the association of a single nucleotide polymorphism (SNP), rs17824933, located in intron 1. CD6 is a cell surface scavenger receptor involved in T-cell activation and proliferation, as well as in thymocyte differentiation. In this study, we performed a haptag SNP screen of the CD6 gene locus using a total of thirteen tagging SNPs, of which three were non-synonymous SNPs, and replicated the recently reported GWAS SNP rs650258 in a Spanish-Basque collection of 814 controls and 823 cases. Validation of the six most strongly associated SNPs was performed in an independent collection of 2265 MS patients and 2600 healthy controls. We identified association of haplotypes composed of two non-synonymous SNPs [rs11230563 (R225W) and rs2074225 (A257V)] in the 2^nd SRCR domain with susceptibility to MS (P _{max(T) permutation} = 1×10⁻⁴). The effect of these haplotypes on CD6 surface expression and cytokine secretion was also tested. The analysis showed significantly different CD6 expression patterns in the distinct cell subsets, i.e. – CD4⁺ naïve cells, P = 0.0001; CD8⁺ naïve cells, P<0.0001; CD4⁺ and CD8⁺ central memory cells, P = 0.01 and 0.05, respectively; and natural killer T (NKT) cells, P = 0.02; with the protective haplotype (RA) showing higher expression of CD6. However, no significant changes were observed in natural killer (NK) cells, effector memory and terminally differentiated effector memory T cells. Our findings reveal that this new MS-associated CD6 risk haplotype significantly modifies expression of CD6 on CD4⁺ and CD8⁺ T cells.     

Adaptation of Mycobacteria to Growth Conditions: A Theoretical Analysis of Changes in Gene Expression Revealed by Microarrays

Background

Microarray analysis is a powerful technique for investigating changes in gene expression. Currently, results (r-values) are interpreted empirically as either unchanged or up- or down-regulated. We now present a mathematical framework, which relates r-values to the macromolecular properties of population-average cells. The theory is illustrated by the analysis of published data for two species; namely, Mycobacterium bovis BCG Pasteur and Mycobacterium smegmatis mc² 155. Each species was grown in a chemostat at two different growth rates. Application of the theory reveals the growth rate dependent changes in the mycobacterial proteomes.

Principal Findings

The r-value r _(i) of any ORF (ORF_(i)) encoding protein p _(i) was shown to be equal to the ratio of the concentrations of p _(i) and so directly proportional to the ratio of the numbers of copies of p _(i) per population-average cells of the two cultures. The proportionality constant can be obtained from the ratios DNA: RNA: protein. Several subgroups of ORFs were identified because they shared a particular r-value. Histograms of the number of ORFs versus the expression ratio were simulated by combining the particular r-values of several subgroups of ORFs. The largest subgroup was ORF_(j) (r _(j)  = 1.00± SD) which was estimated to comprise respectively 59% and 49% of ORFs of M. bovis BCG Pasteur and M. smegmatis mc² 155. The standard deviations reflect the properties of the cDNA preparations investigated.

Significance

The analysis provided a quantitative view of growth rate dependent changes in the proteomes of the mycobacteria studied. The majority of the ORFs were found to be constitutively expressed. In contrast, the protein compositions of the outer permeability barriers and cytoplasmic membranes were found to be dependent on growth rate; thus illustrating the response of bacteria to their environment. The theoretical approach applies to any cultivatable bacterium under a wide range of growth conditions.     

White Matter Deficits in Psychopathic Offenders and Correlation with Factor Structure

Psychopathic offenders show a persistent pattern of emotional unresponsivity to the often horrendous crimes they perpetrate. Recent studies have related psychopathy to alterations in white matter. Therefore, diffusion tensor imaging followed by tract-based spatial statistics (TBSS) analysis in 11 psychopathic offenders matched to 11 healthy controls was completed. Fractional anisotropy was calculated within each voxel and comparisons were made between groups using a permutation test. Any clusters of white matter voxels different between groups were submitted to probabilistic tractography. Significant differences in fractional anisotropy were found between psychopathic offenders and healthy controls in three main white matter clusters. These three clusters represented two major networks: an amygdalo-prefrontal network, and a striato-thalamo-frontal network. The interpersonal/affective component of the PCL-R correlated with white matter deficits in the orbitofrontal cortex and frontal pole whereas the antisocial component correlated with deficits in the striato-thalamo-frontal network. In addition to replicating earlier work concerning disruption of an amygdala-prefrontal network, we show for the first time that white matter integrity in a striato-thalamo-frontal network is disrupted in psychopathic offenders. The novelty of our findings lies in the two dissociable white matter networks that map directly onto the two major factors of psychopathy.     

Water deficit modulates growth,morphology, and the essential oil profile in Lippia alba L. (Verbenaceae) grown in vitro

Lippia alba (Miller) N.E. Brown is an aromatic plant species of great economic importance due to the medicinal properties of its essential oils, which provide stress relief, respiratory and gastrointestinal disease control, and anti-inflammatory and natural sedative effects. The plant is also effective in biological control against various pathogens and in food preservation. Water deficit is the most critical abiotic factor limiting plant growth and morpho-physiological development, as well as production of secondary metabolism compounds. The objective of this work was to evaluate the effect of water deficit on growth, photosynthesis, essential oil profile, and the expression of genes related to the biosynthesis of these compounds in L. alba grown in vitro. Nodal segments were cultured on medium supplemented with 0, 1, 2, and 3% (w/v) polyethylene glycol for 45 days. Water stress had a negative effect on primary metabolism indicators, such as growth, leaf area, and photosynthetic rate; but a positive effect on amino acid and total protein content. Similarly, secondary metabolism exhibited an increase in linalool but a reduction in germacrene levels under water deficit. These findings provide a deeper understanding of how water deficit affects primary and secondary metabolism in L. alba, showing the potential of this medicinal species to adapt to soils with low water availability, while still being able to grow and synthesize essential oils.