Comprehensive characterization of Mycobacterium tuberculosis strains after acquisition of isoniazid resistance

Includes bibliographical references.2016 Fall.Despite the global efforts to reduce tuberculosis (TB) rates, the emergence of drug resistant TB has not allowed effective control of this disease. In the last decade, there were roughly 10 million new TB cases per year and isoniazid resistant (INHr) TB accounted for 9.5% of these cases around the world. In 2012, United States had an interruption in the supply of isoniazid (INH), which increased the likelihood of INH resistance rates. Although INH resistance in Mycobacterium tuberculosis (Mtb) is multigenic, mutations in the catalase-peroxidase (katG) gene predominate amongst INHr Mtb strains. The characterization of the Mtb proteome before and after acquiring INH resistance remains understudied. Additionally, the effect of these drug-resistance-conferring mutations on Mtb fitness and virulence is variable. The purpose of this work is to describe a complete biochemical and immunological characterization of the INHr acquisition in Mtb. In this way, a global exploration of the protein and mycolic acids differences in Mtb cultures, as well as differences in the immune response and bacterial virulence in the mouse model comparing clonal susceptible and INHr pairs of Mtb were evaluated. After this, common trends were analyzed and the findings were interpreted in the context of bacterial metabolism and host-interaction. For this work, two clonal clinical Mtb strains and one laboratory clonal pair of the H37Rv strain with different susceptibility profiles to INH were studied. The H37Rv INHr strain was isolated from a mouse that was exposed to INH in the lab and developed the same katG mutation that one of the clinical INHr strain has (V1A). In all cases, the first strain was susceptible to all tested drugs (mostly known as the INHs strain in this dissertation) while the second strain was resistant only to INH (named INHr throughout this work). The clinical pairs were confirmed as clonal pairs of the Beijing and T genotype respectively by spoligotyping and restriction fragment polymorphism analysis that uses the patterns given by the distribution of the insertion sequence (IS)-6110. Previous whole genome sequencing analysis of the clinical clonal pairs showed a katG mutation and the presence of some additional non-synonymous polymorphisms in the INHr strains. After the proteomic analysis, a katG PCR sequencing confirmed two mutations in katG for the T INHr pair (V1A and E3V) while the L101R mutation previously identified for the Beijing INHr was not confirmed. This mutation was highly unstable and the Beijing INHr might have reversed its phenotype after the absence of INH during in vitro growth. Therefore, the analysis with the Beijing clonal pair is only presented in chapter II. Protein comparison of secreted and cellular fractions (membrane, cytosol and cell wall) between clinical and lab clonal pairs of Mtb before and after acquisition of INH resistance revealed at least 25 commonly altered proteins looking at the same cellular fractions. These proteins were involved in ATP synthase machinery, lipid metabolism, regulatory events, virulence, detoxification and adaptation processes. Western blot analysis supported some of our findings, particularly the lower level of bacterial enzyme KatG in the INHr strains. Mycolic acid (MA) analysis in these clonal pairs did not reveal a common trend in these molecules for INHr strains but generated supporting information about an alternative fatty acid biosynthetic pathway in the clinical INHr strain. These analyses are further described in chapter III. Additionally, differences in bacterial growth, immune response and pathology induced by Mtb strains harboring mutations at the N-terminus of KatG were evaluated in the C57BL/6 mouse model. The results in the mouse study support the idea of the individual effect of specific located mutations in the katG gene together with the associated changes in the bacterial proteome induce differences in the Mtb virulence and pathogenicity. In addition, the in vivo results also suggest the contribution of innate immune response via TLR-2 in the clearance of the INHr-attenuated Mtb strains. Further details of this work are described in chapter IV. This work provides a better understanding of new compensatory mechanisms in Mtb after INH resistance acquisition providing novel information that could be used to address alternative combined therapies as well as the identification of new drug targets in INHr strains. The results presented here also contribute to the generation of new hypothesis regarding RNA decay in Mtb and the need to evaluate if the observed biochemical differences are also associated with the bacterial exposure to the first line drug therapy that occurred in the patient. After the results obtained in this study, a subsequent biochemical analysis of Mtb strains obtained from patients before and after drug treatment is proposed to improve the description of the evolution of the acquired drug resistant phenomena observed in TB cases that limit the global disease control and hence its eradication (chapter V)

Influence of the Ground-State Topology on the Domain-Wall Energy in the Edwards-Anderson +/- J Spin Glass Model

We study the phase stability of the Edwards-Anderson spin-glass model by analyzing the domain-wall energy. For the bimodal distribution of bonds, a topological analysis of the ground state allows us to separate the system into two regions: the backbone and its environment. We find that the distributions of domain-wall energies are very different in these two regions for the three dimensional (3D) case. Although the backbone turns out to have a very high phase stability, the combined effect of these excitations and correlations produces the low global stability displayed by the system as a whole. On the other hand, in two dimensions (2D) we find that the surface of the excitations avoids the backbone. Our results confirm that a narrow connection exists between the phase stability of the system and the internal structure of the ground-state. In addition, for both 3D and 2D we are able to obtain the fractal dimension of the domain wall by direct means.Comment: 4 pages, 3 figures. Accepted for publication in Rapid Communications of Phys. Rev.

Characterization of influenza virus sialic acid receptors in minor poultry species

It is commonly accepted that avian influenza viruses (AIVs) bind to terminal α2,3 sialic acid (SA) residues whereas human influenza viruses bind to α2,6 SA residues. By a series of amino acid changes on the HA surface protein, AIVs can switch receptor specificity and recognize α2,6 SA positive cells, including human respiratory epithelial cells. Animal species, like pigs and Japanese quail, that contain both α2,3 and α2,6 SA become ideal environments for receptor switching. Here, we describe the SA patterns and distributions in 6 common minor domestic poultry species: Peking duck, Toulouse geese, Chinese ring-neck pheasant, white midget turkey, bobwhite quail, and pearl guinea fowl. Lectins specific to α2,3 and α2,6 SA (Maakia amurensis agglutinin and Sambuca nigra agglutinin, respectively) were used to detect SA by an alkaline phosphotase-based method and a fluorescent-based method. Differences in SA moieties and their ability to bind influenza viruses were visualized by fluorescent labeling of 4 different H3N2 influenza viruses known to be specific for one receptor or the other. The geese and ducks showed α2,3 SA throughout the respiratory tract and marginal α2,6 SA only in the colon. The four other avian species showed both α2,3 and α2,6 SA in the respiratory tract and the intestines. Furthermore, the turkey respiratory tract showed a positive correlation between age and α2,6 SA levels. The fact that these birds have both avian and human flu receptors, combined with their common presence in backyard farms and live bird markets worldwide, mark them as potential mixing bowl species and necessitates improved surveillance and additional research about the role of these birds in influenza host switching

Teletrabajo en una empresa retail en tiempos de pandemia, Perú 2020

La actual investigación tuvo como objetivo general analizar el teletrabajo en una empresa retail en tiempos de pandemia, Perú 2020. Desde el aspecto metodológico, se utilizó el enfoque cualitativo, investigación de tipo básico explicativo e interpretativo, el diseño se basa al estudio de casos en relación a la fenomenología. Se emplea la técnica de la entrevista para lo cual se cogió de muestra a 6 participantes, teniendo como herramienta para el análisis el método de información Atlas ti8. De acuerdo a los resultados se evidencia que el teletrabajo va relacionado con el ámbito empresarial, llevando cuatro dimensiones, tales como la cultura corporativa que está ligada a la relación del empleador y el empleado para que genere la confianza de estar en un espacio agradable. También se considera la operatividad para su nueva forma y adaptabilidad de funciones dentro de su espacio, donde comparten con sus familiares y ahí está la distribución de sus laborales para una efectividad de tareas, con acompañamiento de la tecnología y la utilización de herramientas de conectividad para reuniones digitales. Teniendo el soporte mediante capacitaciones para el cuidado de la salud en la técnica de buenas posturas y el desarrollo adecuado de la ergonomía. De igual manera se conecta el ámbito social el cual ayudara al empleado de prevenir el contagio de la covid 19. Esta nueva forma de labores está amparada en un ámbito Jurídico, bajo una norma legal para el cumplimiento y respeto de las horas de labores en el teletrabajo

Host Molecular Responses in Chickens Infected with an Avian Influenza Virus

Avian influenza virus has a segmented RNA genome that allows the virus to evolve continuously and generate new strains. Wild birds serve as natural reservoirs of avian influenza virus and provide a potential source for emergence of new viruses, which traverse host barriers and infect new avian or mammalian species. The mechanisms involved in this process are not completely understood. Our main goal is to understand host-pathogen interactions involved in avian influenza pathogenicity. As part of our approach we studied the effect of pre-exposure of chickens to IBDV (infectious bursal disease virus) on host susceptibility to infection, disease progression, and host molecular responses to infection with a mallard H5N2 low pathogenic avian influenza (LPAI) virus. We found that prior exposure of chickens to IBDV led to increased susceptibility to infection with the mallard H5N2 LPAI virus compared to normal chickens. This increased susceptibility allowed us to further adapt the virus to chickens. After 22 passages (P22) in IBDV-pre-exposed chickens, the LPAI virus replicated substantially better than the wild-type (WT) mallard virus in both IBDV-exposed and normal chickens. Interestingly, the P22 virus showed similar levels of replication in the respiratory and intestinal tracts of both groups, although it caused exacerbated signs of disease and severe lesions in the IBDV-pre-exposed group. We suggest that prior IBDV exposure provides a port of entry for avian influenza in an otherwise resistant chicken population. Furthermore, adaptation of avian influenza (AI) in IBDV-exposed chickens may allow for the selection of AI virus strains with expanded tissue tropism. We also studied the effects of host response to H5N2 AI in normal and IBDV-infected birds using high-throughput gene expression analysis. We demonstrated that IBDV-exposed chickens showed less than optimal humoral responses to LPAI infection as well as alterations in local molecular pathways that eventually led to exacerbated disease and death. At the molecular level we found amino acid substitutions in the surface glycoprotein hemagglutinin (HA). Those changes suggest selection for a virus that binds to and replicates more efficiently in chickens. Taken together our results suggest that IBDV-pre-exposure may play a role in exacerbating AI-induced pathogenicity

Clima organizacional y su relación con la satisfacción laboral del área de cajas de Hipermercados Tottus Jockey Plaza, Lima, 2018

La presente Tesis tuvo como objetivo general determinar la relación que existe entre el Clima Organizacional y la satisfacción laboral del área de cajas de Hipermercados Tottus Jockey Plaza. Para el respectivo análisis se usó el diseño descriptivo correlacional, con una muestra de 70 colaboradores del área de cajas a quienes se aplicó como instrumento una encuesta tipo Likert y estuvo compuesta por 40 preguntas que fueron validas por juicio de expertos y que sirvieron para medir las dimensiones del Clima Organizacional y la Satisfacción Laboral. Después de aplicar el instrumento y recolectar los datos, se consiguió los resultados siguientes a través del programa SPSS, llegando a las siguientes conclusiones: existe correlación positiva moderada, entre el Clima Organizacional y la Satisfacción Laboral, así como el Clima Organizacional con la Satisfacción Laboral

Clima organizacional y su relación con la satisfacción laboral del área de cajas de Hipermercados Tottus Jockey Plaza, Lima, 2018

La presente Tesis tuvo como objetivo general determinar la relación que existe entre el Clima Organizacional y la satisfacción laboral del área de cajas de Hipermercados Tottus Jockey Plaza. Para el respectivo análisis se usó el diseño descriptivo correlacional, con una muestra de 70 colaboradores del área de cajas a quienes se aplicó como instrumento una encuesta tipo Likert y estuvo compuesta por 40 preguntas que fueron validas por juicio de expertos y que sirvieron para medir las dimensiones del Clima Organizacional y la Satisfacción Laboral. Después de aplicar el instrumento y recolectar los datos, se consiguió los resultados siguientes a través del programa SPSS, llegando a las siguientes conclusiones: existe correlación positiva moderada, entre el Clima Organizacional y la Satisfacción Laboral, así como el Clima Organizacional con la Satisfacción Laboral

Percolation on patchwise heterogeneous surfaces under equilibrium conditions

The site percolation problem on square lattices whose sites are grouped in two types of energetically different patches is studied. Several lattices formed by collections of either randomly or orderly localized and no overlapped patches of different sizes are generated. The system is characterized by two parameters, namely, the size of each patch, l, and the energy difference between the two kind of sites, E. Particles are adsorbed at equilibrium on the lattice. The critical coverage is determined by means of Monte Carlo simulations and finite-size scaling analysis. The percolative behavior of the system as a function of the parameters characterizing the heterogeneity of the energetic surface topography is presented and discussed.Fil: Gimenez, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Ramirez Pastor, Antonio Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Nieto Quintas, Felix Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentin