2013 REU Poster: Purification and Characterization of a Ferredoxin from Mycobacterium tuberculosis

Poster presentation at REU Summer's End Research Symposium, 2013, by REU participant Jonas A, de Oliveira, MassBay Community College - Sean Elliott group, Evan Judd lab mentorM. tuberculosis possesses a sulfite reductase (MtsirA) that is over-expressed when the bacteria is in its dormant stage of infection. MtSirA catalyzes the six-electron reduction of sulfite to sulfide. Previous kinetic studies of MtsirA have used methyl viologen (MV), a chemical reductant, as an electron donor. The goal of this work is to purify and characterize a ferredoxin from M. tuberculosis (MtFd) and determine if MtFd can act as an electron donor to mtSirA, with the ultimate goal of using it as a more physiologically relevant electron donor in kinetic studies of mtSirA. We have found that that MtFd purifies without a cluster and must be chemically reconstituted. MtFd likely contains a [4Fe-4S] cluster, and may be able to donate electrons to mtSirA.NSF-RE

Transmission coefficient and two-fold degenerate discrete spectrum of spin-1 bosons in a double-step potential

The scattering of spin-1 bosons in a nonminimal vector double-step potential is described in terms of eigenstates of the helicity operator and it is shown that the transmission coefficient is insensitive to the choice of the polarization of the incident beam. Poles of the transmission amplitude reveal the existence of a two-fold degenerate spectrum. The results are interpreted in terms of solutions of two coupled effective Schr\"{o}dinger equations for a finite square well with additional $\delta$-functions situated at the borders.Comment: arXiv admin note: substantial text overlap with arXiv:1203.119

Lactobacillus crispatus as the etiological agent in cytolytic vaginosis

Introduction: Lactobacillus spp. dominate the vaginal niche but can also be involved in other vaginal dysbiosis, such as cytolytic vaginosis (CV), which remains poorly studied. It is characterized by a cryptic symptomatology, that often confounds the clinic. Goals: The aim of this work was to search for the etiological agent of CV, by studying the vaginal microbiome and metabolomics of women afflicted with this disease and compare it with women with other clinical diagnostic. Methods: Twenty-one vaginal washes have been collected from women attending a gynaecology consultation of a private clinic. The samples were categorized according with clinical diagnosis at the time of sampling (CV, 11; vulvovaginal candidosis, 8; Healthy, 2). The distribution of bacterial species, and their prevalence was assessed by next-generation sequencing of the 16S V4 region. In addition, total lactate D-lactic acid and L-lactic acid was quantified in all washes by a commercial kit, as well as lactate dehydrogenase (LDH) activity. Results: L. crispatus was dominant (>70%) in all CV samples. Lactate was increased in CV in comparison with other cases. The presence of D-lactic acid isomer was associated with presence of L. crispatus. LDH activity was increased in vaginal washes that tested positive for the presence of L. crispatus, however no direct association was found with CV cases. Discussion/Conclusions: The microbiome of women afflicted with CV was dominated in all cases by L. crispatus, contrarily with the results obtained for women diagnosed with other clinical symptomatology. In addition, the finding that an increase in D-lactic acid is associated with CV patients can be related to the role of L. crispatus in CV. The determination of LDH activity did not correlate exclusively with CV cases. On the other hand, D-lactic acid and total lactate quantification could be used as a valuable biomarker to diagnose this cryptic vaginal infection.info:eu-repo/semantics/publishedVersio

Interplay between structure and density anomaly for an isotropic core-softened ramp-like potential

Using molecular dynamics simulations and integral equations we investigate the structure, the thermodynamics and the dynamics of a system of particles interacting through a continuous core- softened ramp-like interparticle potential. We found density, dynamic and structural anomalies similar to that found in water. Analysis of the radial distribution function for several temperatures at fixed densities show a pattern that may be related to the origin of density anomaly.Comment: 7 pages, 3 figure

Learning roadmaps for Higher Education

An integrated platform for the support of teaching activities as been developed and deployed at the Aveiro Norte Polytechnic School of the University of Aveiro. In this paper we present an approach to Learning Roadmaps for Higher Education based on this platform. The aprend.e platform – Electronic Integrated System for Learning and Training - has at its core a Learning Management System with a number of plugins. It represents a new challenge for the University of Aveiro for higher education and is already being at its core is the concept of learning roadmaps that act upon two fundamental axes: education and learning. For the teachers, it aims at becoming a self-supporting tool that stimulates the organization and management of the course materials (lectures, presentations, multimedia content, and evaluation materials, amongst others). For the students, the learning roadmap aims at promoting self-study and supervised study, endowing the pupil with the capabilities to find the relevant information and to capture the concepts in the study materials. The outcome will be a stimulating learning process together with an organized management of those materials