Investigation into the role of an extracellular loop in mediating proton-evoked inhibition of voltage-gated sodium channels

Proton-evoked activation of sensory neurons is counteracted by inhibition of voltage-gated Na+ channels, and the low acid-sensitivity of sensory neuron of the African naked mole-rat (ANMr) was reported to be due to a strong proton-evoked block of ANMrNav1.7. Here we aimed to reevaluate the role of the suggested negatively-charged motif in the ANMrNav1.7 domain IV P-loop for inhibition by protons. Patch clamp recordings were performed on the recombinant α-subunits Nav1.2–1.8. The insertion of the negatively charged motif (EKE) of ANMrNav1.7 into human Nav1.7 results in an increased proton-evoked tonic inhibition, but also in a reduced channel function. While the voltage-dependency of fast inactivation is changed in hNav1.7-EKE, pH 6.4 fails to induce a significant shift in both constructs. Proton-evoked inhibition of other channel α-subunits reveals a discrete differential inhibition among α-subunits with hNav1.7 displaying the lowest proton-sensitivity. The mutant hNav1.7-EKE displays a similar proton-sensitivity as Nav1.2, Nav1.3, Nav1.6 and Nav1.8. Overall, a correlation between proton-evoked inhibition and motif charge was not evident. Accordingly, a homology model of hNav1.7 shows that the EKE motif residues do not contribute to the pore lumen. Our data confirms that a negative charge of a postulated proton-motif encodes for a high proton-sensitivity when inserted into hNav1.7. However, a negatively charged motif is not a reliable predictor for a high proton-sensitivity in other α-subunits. Given the distance of the proton-motif from the pore mouth it seems unlikely that a blocking mechanism involving direct obstruction of the pore underlies the observed proton-evoked channel inhibition

A CURE on the Evolution of Antibiotic Resistance in <i>Escherichia coli</i> Improves Student Conceptual Understanding

We developed labs on the evolution of antibiotic resistance to assess the costs and benefits of replacing traditional laboratory exercises in an introductory biology course for majors with a course-based undergraduate research experience (CURE). To assess whether participating in the CURE imposed a cost in terms of exam performance, we implemented a quasi-experiment in which four lab sections in the same term of the same course did the CURE labs, while all other students did traditional labs. To assess whether participating in the CURE impacted other aspects of student learning, we implemented a second quasi-experiment in which all students either did traditional labs over a two-quarter sequence or did CURE labs over a two-quarter sequence. Data from the first experiment showed minimal impact on CURE students' exam scores, while data from the second experiment showed that CURE students demonstrated a better understanding of the culture of scientific research and a more expert-like understanding of evolution by natural selection. We did not find disproportionate costs or benefits for CURE students from groups that are minoritized in science, technology, engineering, and mathematics

Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli

Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.  Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins.  Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets

Genetic Association and Altered Gene Expression of Mir-155 in Multiple Sclerosis Patients

Multiple sclerosis (MS) is a complex autoimmune disease of the central nervous system characterized by chronic inflammation, demyelination, and axonal damage. As microRNA (miRNA)-dependent alterations in gene expression in hematopoietic cells are critical for mounting an appropriate immune response, miRNA deregulation may result in defects in immune tolerance. In this frame, we sought to explore the possible involvement of miRNAs in MS pathogenesis by monitoring the differential expression of 22 immunity-related miRNAs in peripheral blood mononuclear cells of MS patients and healthy controls, by using a microbead-based technology. Three miRNAs resulted >2 folds up-regulated in MS vs controls, whereas none resulted down-regulated. Interestingly, the most up-regulated miRNA (mir-155; fold change = 3.30; P = 0.013) was previously reported to be up-regulated also in MS brain lesions. Mir-155 up-regulation was confirmed by qPCR experiments. The role of mir-155 in MS susceptibility was also investigated by genotyping four single nucleotide polymorphisms (SNPs) mapping in the mir-155 genomic region. A haplotype of three SNPs, corresponding to a 12-kb region encompassing the last exon of BIC (the B-cell Integration Cluster non-coding RNA, from which mir-155 is processed), resulted associated with the disease status (P = 0.035; OR = 1.36, 95% CI = 1.05–1.77), suggesting that this locus strongly deserves further investigations

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Detection and kinetics of persistent neutralizing anti-interferon-beta antibodies in patients with multiple sclerosis. Results from the ABIRISK prospective cohort study

Two validated assays, a bridging ELISA and a luciferase-based bioassay, were compared for detection of anti-drug antibodies (ADA) against interferon-beta (IFN-beta) in patients with multiple sclerosis. Serum samples were tested from patients enrolled in a prospective study of 18 months. In contrast to the ELISA, when IFN-beta-specific rabbit polyclonal and human monoclonal antibodies were tested, the bioassay was the more sensitive to detect IFN-beta ADA in patients' sera. For clinical samples, selection of method of ELISA should be evaluated prior to the use of a multi-tiered approach. A titer threshold value is reported that may be used as a predictor for persistently positive neutralizing ADA