Insights into N-calls of mitochondrial DNA sequencing using MitoChip v2.0

Developments in DNA resequencing microarrays include mitochondrial DNA (mtDNA) sequencing and mutation detection. Failure by the microarray to identify a base, compared to the reference sequence, is designated an 'N-call.' This study re-examined the N-call distribution of mtDNA samples sequenced by the Affymetrix MitoChip v.2.0, based on the hypothesis that N-calls may represent insertions or deletions (indels) in mtDNA.We analysed 16 patient mtDNA samples using MitoChip. N-calls by the proprietary GSEQ software were significantly reduced when either of the freeware on-line algorithms ResqMi or sPROFILER was utilized. With sPROFILER, this decrease in N-calls had no effect on the homoplasmic or heteroplasmic mutation levels compared to GSEQ software, but ResqMi produced a significant change in mutation load, as well as producing longer N-cell stretches. For these reasons, further analysis using ResqMi was not attempted. Conventional DNA sequencing of the longer N-calls stretches from sPROFILER revealed 7 insertions and 12 point mutations. Moreover, analysis of single-base N-calls of one mtDNA sample found 3 other point mutations.Our study is the first to analyse N-calls produced from GSEQ software for the MitoChipv2.0. By narrowing the focus to longer stretches of N-calls revealed by sPROFILER, conventional sequencing was able to identify unique insertions and point mutations. Shorter N-calls also harboured point mutations, but the absence of deletions among N-calls suggests that probe confirmation affects binding and thus N-calling. This study supports the contention that the GSEQ is more capable of assigning bases when used in conjunction with sPROFILER

Nanosize Titanium Dioxide Stimulates Reactive Oxygen Species in Brain Microglia and Damages Neurons in Vitro

BackgroundTitanium dioxide is a widely used nanomaterial whose photo-reactivity suggests that it could damage biological targets (e.g., brain) through oxidative stress (OS).ObjectivesBrain cultures of immortalized mouse microglia (BV2), rat dopaminergic (DA) neurons (N27), and primary cultures of embryonic rat striatum, were exposed to Degussa P25, a commercially available TiO2 nanomaterial. Physical properties of P25 were measured under conditions that paralleled biological measures.FindingsP25 rapidly aggregated in physiological buffer (800–1,900 nm; 25°C) and exposure media (~ 330 nm; 37°C), and maintained a negative zeta potential in both buffer (–12.2 ± 1.6 mV) and media (–9.1 ± 1.2 mV). BV2 microglia exposed to P25 (2.5–120 ppm) responded with an immediate and prolonged release of reactive oxygen species (ROS). Hoechst nuclear stain was reduced after 24-hr (≥100 ppm) and 48-hr (≥2.5 ppm) exposure. Microarray analysis on P25-exposed BV2 microglia indicated up-regulation of inflammatory, apoptotic, and cell cycling pathways and down-regulation of energy metabolism. P25 (2.5–120 ppm) stimulated increases of intracellular ATP and caspase 3/7 activity in isolated N27 neurons (24–48 hr) but did not produce cytotoxicity after 72-hr exposure. Primary cultures of rat striatum exposed to P25 (5 ppm) showed a reduction of immunohistochemically stained neurons and microscopic evidence of neuronal apoptosis after 6-hr exposure. These findings indicate that P25 stimulates ROS in BV2 microglia and is nontoxic to isolated N27 neurons. However, P25 rapidly damages neurons at low concentrations in complex brain cultures, plausibly though microglial generated ROS

Structural arrangement of the transmission interface in the antigen ABC transport complex TAP

The transporter associated with antigen processing (TAP) represents a focal point in the immune recognition of virally or malignantly transformed cells by translocating proteasomal degradation products into the endoplasmic reticulum–lumen for loading of MHC class I molecules. Based on a number of experimental data and the homology to the bacterial ABC exporter Sav1866, we constructed a 3D structural model of the core TAP complex and used it to examine the interface between the transmembrane and nucleotide-binding domains (NBD) by cysteine-scanning and cross-linking approaches. Herein, we demonstrate the functional importance of the newly identified X-loop in the NBD in coupling substrate binding to downstream events in the transport cycle. We further verified domain swapping in a heterodimeric ABC half-transporter complex by cysteine cross-linking. Strikingly, either substrate binding or translocation can be blocked by cross-linking the X-loop to coupling helix 2 or 1, respectively. These results resolve the structural arrangement of the transmission interface and point to different functions of the cytosolic loops and coupling helices in substrate binding, signaling, and transport

Proceedings of EADPH Pre -Congress Workshop held on Wednesday, 11 September 2019 at Het Pand, University of Ghent, Belgium. Best practices in dental curricula development – a follow-up to the 2018 EADPH Pre-Congress Workshop

This document reports the proceedings of a workshop held in Ghent on 11 September 2019, the day before the annual congress of the European Association of Dental Public Health. It is taken directly from the transcription of an audio recording. The workshop consisted of eight short presentations which described curriculum changes and examples of inter-professional education and practice involving dental public health in European countries. The presentations were followed by discussions in four small working groups and reports from each group which highlighted achievements, barriers and challenge

The alpha-galactosidase A p.Arg118Cys variant does not cause a Fabry disease phenotype: data from individual patients and family studies

Acessível em: www.ncbi.nlm.nih.gov/pmc/articles/PMC4423738/Lysosomal α-galactosidase A (α-Gal) is the enzyme deficient in Fabry disease (FD), an X-linked glycosphingolipidosis caused by pathogenic mutations affecting the GLA gene. The early-onset, multi-systemic FD classical phenotype is associated with absent or severe enzyme deficiency, as measured by in vitro assays, but patients with higher levels of residual α-Gal activity may have later-onset, more organ-restricted clinical presentations. A change in the codon 118 of the wild-type α-Gal sequence, replacing basic arginine by a potentially sulfhydryl-binding cysteine residue - GLA p.(Arg118Cys) -, has been recurrently described in large FD screening studies of high-risk patients. Although the Cys118 allele is associated with high residual α-Gal activity in vitro, it has been classified as a pathogenic mutation, mainly on the basis of theoretical arguments about the chemistry of the cysteine residue. However its pathogenicity has never been convincingly demonstrated by pathology criteria. We reviewed the clinical, biochemical and histopathology data obtained from 22 individuals of Portuguese and Spanish ancestry carrying the Cys118 allele, including 3 homozygous females. Cases were identified either on the differential diagnosis of possible FD manifestations and on case-finding studies (n=11; 4 males), or on unbiased cascade screening of probands' close relatives (n=11; 3 males). Overall, those data strongly suggest that the GLA p.(Arg118Cys) variant does not segregate with FD clinical phenotypes in a Mendelian fashion, but might be a modulator of the multifactorial risk of cerebrovascular disease. The Cys118 allelic frequency in healthy Portuguese adults (n=696) has been estimated as 0.001, therefore not qualifying for "rare" condition

Systematic reconstruction of TRANSPATH data into Cell System Markup Language

<p>Abstract</p> <p>Background</p> <p>Many biological repositories store information based on experimental study of the biological processes within a cell, such as protein-protein interactions, metabolic pathways, signal transduction pathways, or regulations of transcription factors and miRNA. Unfortunately, it is difficult to directly use such information when generating simulation-based models. Thus, modeling rules for encoding biological knowledge into system-dynamics-oriented standardized formats would be very useful for fully understanding cellular dynamics at the system level.</p> <p>Results</p> <p>We selected the TRANSPATH database, a manually curated high-quality pathway database, which provides a plentiful source of cellular events in humans, mice, and rats, collected from over 31,500 publications. In this work, we have developed 16 modeling rules based on hybrid functional Petri net with extension (HFPNe), which is suitable for graphical representing and simulating biological processes. In the modeling rules, each Petri net element is incorporated with Cell System Ontology to enable semantic interoperability of models. As a formal ontology for biological pathway modeling with dynamics, CSO also defines biological terminology and corresponding icons. By combining HFPNe with the CSO features, it is possible to make TRANSPATH data to simulation-based and semantically valid models. The results are encoded into a biological pathway format, Cell System Markup Language (CSML), which eases the exchange and integration of biological data and models.</p> <p>Conclusion</p> <p>By using the 16 modeling rules, 97% of the reactions in TRANSPATH are converted into simulation-based models represented in CSML. This reconstruction demonstrates that it is possible to use our rules to generate quantitative models from static pathway descriptions.</p

A critical review on modelling formalisms and simulation tools in computational biosystems

Integration of different kinds of biological processes is an ultimate goal for whole-cell modelling. We briefly review modelling formalisms that have been used in Systems Biology and identify the criteria that must be addressed by an integrating framework capable of modelling, analysing and simulating different biological networks. Aware that no formalism can fit all purposes we realize Petri nets as a suitable model for Metabolic Engineering and take a deeper perspective on the role of this formalism as an integrating framework for regulatory and metabolic networks.Research supported by PhD grant SFRH/BD/35215/2007 from the Fundacao para a Ciencia e a Tecnologia (FCT) and the MIT-Portugal program

Near-Membrane Dynamics and Capture of TRPM8 Channels within Transient Confinement Domains

The cold and menthol receptor, TRPM8, is a non-selective cation channel expressed in a subset of peripheral neurons that is responsible for neuronal detection of environmental cold stimuli. It was previously shown that members of the transient receptor potential (TRP) family of ion channels are translocated toward the plasma membrane (PM) in response to agonist stimulation. Because the spatial and temporal dynamics of cold receptor cell-surface residence may determine neuronal activity, we hypothesized that the movement of TRPM8 to and from the PM might be a regulated process. Single particle tracking (SPT) is a useful tool for probing the organization and dynamics of protein constituents in the plasma membrane.We used SPT to study the receptor dynamics and describe membrane/near-membrane behavior of particles containing TRPM8-EGFP in transfected HEK-293T and F-11 cells. Cells were imaged using total internal reflection fluorescence (TIRF) microscopy and the 2D and 3D trajectories of TRPM8 molecules were calculated by analyzing mean-square particle displacement against time. Four characteristic types of motion were observed: stationary mode, simple Brownian diffusion, directed motion, and confined diffusion. In the absence of cold or menthol to activate the channel, most TRPM8 particles move in network covering the PM, periodically lingering for 2–8 s in confined microdomains of about 800 nm radius. Removing cholesterol with methyl-beta-cyclodextrin (MβCD) stabilizes TRPM8 motion in the PM and is correlated with larger TRPM8 current amplitude that results from an increase in the number of available channels without a change in open probability.These results reveal a novel mechanism for regulating TRPM8 channel activity, and suggest that PM dynamics may play an important role in controlling electrical activity in cold-sensitive neurons

Degradation of keratin substrates by keratinolytic fungi

Background: The hydrolysis of keratin wastes by microorganisms is considered a biotechnological alternative for recycling and valorization through keratinolytic microorganisms. Despite their resistant structure, keratin wastes can be efficiently degraded by various microorganisms through the secretion of keratinases,which are promising enzymes for several applications, including detergents, fertilizers, and leather and textile industry. In an attempt to isolate keratinolytic microorganisms that can reach commercial exploitation as keratinase producers, the current work assesses the dynamics of keratin biodegradation by several keratinolytic fungal strains isolated from soil. The activity of fungal strains to degrade keratin substrates was evaluated by SEM, FTRIR-ATR spectra and TGA analysis. Results: SEM observations offered relevant information on interactions between microorganism and structural elements of hair strands. FTIR spectra of the bands at 1035\u20131075 cm-1 assigned to sulfoxide bond appeared because of S\u2013S bond breaking, which demonstrated the initiation of keratin biodegradation. According to TGA, in the second zone of thermal denaturation, where keratin degradation occurs, the highest weight loss of 71.10% was obtained for sample incubated with Fusarium sp. 1A. Conclusions: Among the tested strains, Fusarium sp. 1A was the most active organism in the degradation process with the strongest denaturation of polypeptide chains. Because keratinolytic microorganisms and their enzymes keratinases represent a subject of scientific and economic interest because of their capability to hydrolyze keratin, Fusarium sp. 1A was selected for further studies