Deletion of BmoR affects the expression of genes related to thiol/disulfide balance in Bacteroides fragilis

Bacteroides fragilis, an opportunistic pathogen and commensal bacterium in the gut, is one the most aerotolerant species among strict anaerobes. However, the mechanisms that control gene regulation in response to oxidative stress are not completely understood. In this study, we show that the MarR type regulator, BmoR, regulates the expression of genes involved in the homeostasis of intracellular redox state. Transcriptome analysis showed that absence of BmoR leads to altered expression in total of 167 genes. Sixteen of these genes had a 2-fold or greater change in their expression. Most of these genes are related to LPS biosynthesis and carbohydrates metabolism, but there was a signifcant increase in the expression of genes related to the redox balance inside the cell. A pyridine nucleotide-disulfde oxidoreductase located directly upstream of bmoR was shown to be repressed by direct binding of BmoR to the promoter region. The expression of two other genes, coding for a thiosulphate:quinoneoxidoreductase and a thioredoxin, are indirectly afected by bmoR mutation during oxygen exposure. Phenotypic assays showed that BmoR is important to maintain the thiol/disulfde balance in the cell, confrming its relevance to B. fragilis response to oxidative stress

From sparse to dense and from assortative to disassortative in online social networks

Inspired by the analysis of several empirical online social networks, we propose a simple reaction-diffusion-like coevolving model, in which individuals are activated to create links based on their states, influenced by local dynamics and their own intention. It is shown that the model can reproduce the remarkable properties observed in empirical online social networks; in particular, the assortative coefficients are neutral or negative, and the power law exponents are smaller than 2. Moreover, we demonstrate that, under appropriate conditions, the model network naturally makes transition(s) from assortative to disassortative, and from sparse to dense in their characteristics. The model is useful in understanding the formation and evolution of online social networks.Comment: 10 pages, 7 figures and 2 table

Validação brasileira do Instrumento de Qualidade de Vida/espiritualidade, religião e crenças pessoais

OBJETIVO: Analisar propriedades psicométricas do Instrumento de Qualidade de Vida da Organização Mundial da Saúde - Módulo Espiritualidade, Religiosidade e Crenças Pessoais (WHOQOL-SRPB). MÉTODOS: O WHOQOL-SRPB, a Escala de Coping Religioso/Espiritual Abreviada (CRE-Breve), o WHOQOL-Breve e o BDI foram consecutivamente aplicados em amostra de conveniência de 404 pacientes e funcionários de hospital universitário e funcionários de universidade, em Porto Alegre, RS, entre 2006 e 2009. A amostra foi estratificada por sexo, idade, estado de saúde e religião/crença. O reteste dos dois primeiros instrumentos foi realizado com 54 participantes. Análises fatoriais exploratórias do WHOQOL-SRPB pelo método dos componentes principais foram realizadas sem delimitar o número de fatores, solicitando oito fatores e em conjunto com os itens do WHOQOL-Breve. RESULTADOS: O WHOQOL-SRPB em português brasileiro (Domínio SRPB-Geral) apresentou validade de construto, com validade discriminativa entre crentes de não-crentes (t = 7,40; p = 0,0001); validade relacionada ao critério concorrente, discriminando deprimidos de não-deprimidos (t = 5,03; p = 0,0001); validade convergente com o WHOQOL-Breve (com físico r = 0,18; psicológico r = 0,46; social r = 0,35; ambiental r = 0,29; global r = 0,23; p = 0,0001) e com o Domínio SRPB do WHOQOL-100 (r = 0,78; p = 0,0001); e validade convergente/discriminante com a Escala CRE-Breve (com CREpositivo r = 0,64; p = 0,0001/CREnegativo r = -0,03; p = 0,554). Observou-se excelente fidedignidade teste-reteste (t = 0,74; p = 0,463) e consistência interna (α = 0,96; correlação intrafatorial 0,87 > r > 0,60, p = 0,0001). As análises fatoriais exploratórias realizadas corroboraram a estrutura de oito fatores do estudo multicêntrico do WHOQOL-SRPB. CONCLUSÕES: O WHOQOL-SRPB em português brasileiro apresentou boas qualidades psicométricas e uso válido e fidedigno para uso no Brasil. Sugerem-se novos estudos com populações específicas, como diferentes religiões, grupos culturais e/ou doenças.OBJETIVO: Analizar propiedades psicométricas del Instrumento de Calidad de Vida de la OMS - Módulo Espiritualidad, Religiosidad y Creencias Personales (WHOQOL-SRPB). MÉTODOS: El WHOQOL-SRPB, la Escala de Coping Religioso/Espiritual Abreviada (CRE-Breve), el WHOQOL-Breve y el BDI fueron consecutivamente aplicados en muestra de conveniencia de 404 pacientes y funcionarios de hospital universitario y funcionarios de universidad, en Porto Alegre, Sur de Brasil, entre 2006 y 2009. La muestra fue estratificada por sexo, edad, estado de salud y religión/creencia. La reevaluación de los dos primeros instrumentos fue realizada por 54 participantes. Análisis factoriales exploratorias del WHOQOL-SRPB por el método de los componentes principales fueron realizadas, sin delimitar el número de factores, solicitando ocho factores y en conjunto con los itens del WHOQOL-Breve. RESULTADOS: El WHOQOL-SRPB en portugués-brasileño (Dominio SRPB-General) presentó validez de constructo, con validez discriminativa entre creyentes de no creyentes (t=7,40; p=0,0001); validez relacionada con el criterio concurrente, discriminando deprimidos de no deprimidos (t=5,03; p=0,0001); validez convergente con el WHOQOL-Breve (con físico r=0,18; psicológico r=0,46; social r=0,35; ambiental r=0,29; global r=0,23; p=0,0001) y con el Dominio-SRPB del WHOQOL-100 (r=0,78; p=0,0001); y validez convergente/discriminante con la Escala CRE-Breve (con CRE positivo r=0,64; p=0,0001/CRE negativo r=-0,03; p=0,554). Se observó excelente fidedignidad test-retest (t=0,74; p=0,463) y consistencia interna (α=0,96; correlación intrafactorial 0,87>r>0,60, p=0,0001). Los análisis factoriales exploratorios realizados corroboran la estructura de ocho factores de estudio multicéntrico del WHOQOL-SRPB. CONCLUSIONES: El WHOQOL-SRPB en portugués-brasileño presentó buenas cualidades psicométricas, siendo válido y fidedigno para uso en Brasil. Se sugieren nuevos estudios con poblaciones específicas, como diferentes religiones, grupos culturales y/o enfermedades.OBJECTIVE: To analyze the psychometric properties of the World Health Organization's Quality of Life Instrument - Spirituality, Religion and Personal Beliefs module (WHOQOL-SRPB). METHODS: The WHOQOL-SRPB, the Brief Spiritual/Religious Coping Scale (Brief-SRCOPE Scale), the WHOQOL-BREF and the Beck Depression Inventory (BDI) were consecutively applied in a convenience sample of 404 patients and workers of a university hospital and workers of a university, in the city of Porto Alegre, Southern Brazil, between 2006 and 2009. The sample was stratified by sex, age, health status and religion/belief. The retest of the two first instruments was conducted with 54 participants. Exploratory factorial analyses of the WHOQOL-SRPB with the method of main components were performed, without limiting the number of factors, and requiring eight factors concomitantly with the WHOQOL-BREF items. RESULTS: The Brazilian Portuguese version of the WHOQOL-SRPB (General SRPB-Domain) showed construct validity, with a discriminatory validity between believers and non-believers (t = 7.40; p = 0.0001); concurrent criterion-related validity, distinguishing depressed individuals from non-depressed ones (t = 5.03; p = 0.0001); convergent validity with the WHOQOL-BREF (physical r = 0.18; psychological r = 0.46; social r = 0.35; environmental r = 0.29; global r = 0.23; p = 0.0001) and with the SRPB-Domain of the WHOQOL-100 (r = 0.78; p = 0.0001); and convergent/discriminatory validity with the brief SRCOPE Scale (with positive SRCOPE r = 0.64; p = 0.0001/negative SRCOPE r = -0.03; p = 0.554). Excellent test-retest reliability (t = 0.74; p = 0.463) and internal consistency (α = 0.96; intrafactorial correlation 0.87 > r > 0.60; p = 0.0001) were observed. The exploratory factorial analyses performed corroborated the eight-factor structure of the WHOQOL-SRPB multicenter study. CONCLUSIONS: The Brazilian Portuguese version of the WHOQOL-SRPB showed good psychometric qualities and use valid and reliable in Brazil. It is suggested that new studies be conducted with specific populations, such as different religions, cultural groups and/or diseases

Quality of life in caregivers of children and adolescents with Osteogenesis Imperfecta

Background: Osteogenesis imperfecta (OI) is a group of genetic disorders of collagen biosynthesis, characterized by low bone density leading to fractures. Most patients exhibit functional impairment and require the aid of a caregiver. The aim of this study is to assess the quality of life (QoL) of caregivers of patients with OI. Methods: In this cross-sectional study, a convenience sampling strategy was used to enroll adult caregivers of children and adolescents with OI who attended a referral center in southern Brazil. The WHOQOL-BREF instrument was used to assess QoL. Results: Twenty-four caregivers of 27 patients (10 with type I, 4 with type III, and 13 with type IV OI) were included in the study. Eighteen caregivers were the patients’ mothers, two had OI, and 22 cared for only one patient. Mean WHOQOL-BREF scores were 14.59 for the physical health domain, 13.80 for the psychological domain, 15.19 for the social relationships domain, and 12.87 for the environmental domain; the mean total QoL score was 14.16. QoL scores did not differ significantly according to patients’ OI type or number of fractures. Economic status was not correlated significantly with QoL scores. Conclusions: QoL appears to be impaired in caregivers of patients with OI. Additional studies are required to confirm these findings and to ascertain which factors account for this phenomenon

Astrobiological Complexity with Probabilistic Cellular Automata

Search for extraterrestrial life and intelligence constitutes one of the major endeavors in science, but has yet been quantitatively modeled only rarely and in a cursory and superficial fashion. We argue that probabilistic cellular automata (PCA) represent the best quantitative framework for modeling astrobiological history of the Milky Way and its Galactic Habitable Zone. The relevant astrobiological parameters are to be modeled as the elements of the input probability matrix for the PCA kernel. With the underlying simplicity of the cellular automata constructs, this approach enables a quick analysis of large and ambiguous input parameters' space. We perform a simple clustering analysis of typical astrobiological histories and discuss the relevant boundary conditions of practical importance for planning and guiding actual empirical astrobiological and SETI projects. In addition to showing how the present framework is adaptable to more complex situations and updated observational databases from current and near-future space missions, we demonstrate how numerical results could offer a cautious rationale for continuation of practical SETI searches.Comment: 37 pages, 11 figures, 2 tables; added journal reference belo

Microevolution of Helicobacter pylori during prolonged infection of single hosts and within families

Our understanding of basic evolutionary processes in bacteria is still very limited. For example, multiple recent dating estimates are based on a universal inter-species molecular clock rate, but that rate was calibrated using estimates of geological dates that are no longer accepted. We therefore estimated the short-term rates of mutation and recombination in Helicobacter pylori by sequencing an average of 39,300 bp in 78 gene fragments from 97 isolates. These isolates included 34 pairs of sequential samples, which were sampled at intervals of 0.25 to 10.2 years. They also included single isolates from 29 individuals (average age: 45 years) from 10 families. The accumulation of sequence diversity increased with time of separation in a clock-like manner in the sequential isolates. We used Approximate Bayesian Computation to estimate the rates of mutation, recombination, mean length of recombination tracts, and average diversity in those tracts. The estimates indicate that the short-term mutation rate is 1.4×10−6 (serial isolates) to 4.5×10−6 (family isolates) per nucleotide per year and that three times as many substitutions are introduced by recombination as by mutation. The long-term mutation rate over millennia is 5–17-fold lower, partly due to the removal of non-synonymous mutations due to purifying selection. Comparisons with the recent literature show that short-term mutation rates vary dramatically in different bacterial species and can span a range of several orders of magnitude

IFNAR1-Signalling Obstructs ICOS-mediated Humoral Immunity during Non-lethal Blood-Stage Plasmodium Infection

Funding: This work was funded by a Career Development Fellowship (1028634) and a project grant (GRNT1028641) awarded to AHa by the Australian National Health & Medical Research Council (NHMRC). IS was supported by The University of Queensland Centennial and IPRS Scholarships. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Estratégias de coping utilizadas por familiares de indivíduos em tratamento hemodialítico

This descriptive, qualitative study aims to identify the coping strategies used most by the family members of patients with chronic kidney disease receiving hemodialysis. The data were collected through interviews, with the Coping Strategies Inventory questionnaire administered to ten family members, and were submitted to descriptive statistics and to thematic content analysis. The strategy used most was escape-avoidance, demonstrating that the family members prefer not to face the situation. The second most-used strategy was social support, ratified by the fact that they stated that they talk with other persons and professionals, seeking information about the problem, and because they accept the support received positively. The third was problem resolution, represented by the attitude of accepting responsibility for the care, either through strong affective bonds or through a feeling of responsibility established prior to the disease. The families use coping strategies of different intensities, while, nevertheless, indicating involvement and major participation in the care for the patient.Estudio cualitativo, que trató de identificar las estrategias de afrontamiento empleadas por las familias de los pacientes con insuficiencia renal crónica en hemodiálisis. Se aplicó el Inventario de Estrategias de Afrontamiento y una questión abierta con diez familiares. Los datos cuantitativos fueron sometidos a procedimientos estatísticos y análisis de contenido cualitativo. La estrategia de mayor utilización fue el escape y evitación (oito), lo que demuestra que los miembros de las familisa preferían no tener que enfrentar esta situación. La siguiente estrategia fue utilizada más apoyo social, ya hablé con otras personas y profesionales que buscan información sobre el problema, y aceptar el apoyo positivo recibido. A terceira foi resolução de problemas, representada pela atitude em assumir o cuidado, seja pelo forte vínculo afetivo ou pelo sentimento de responsabilidade já estabelecido antes da doença. Familias de las estrategias de afrontamiento empleadas con diferentes intensidades, pero mostrando una gran implicación y la participación en el cuidado del paciente crónico.Estudo descritivo, de natureza quali-quantitativa, que objetivou identificar as estratégias de enfrentamento mais utilizadas por familiares de pacientes com doença renal crônica em hemodiálise. Os dados foram coletados por meio de entrevista, com aplicação do Inventário de Estratégias de Coping a dez familiares, e submetidos à estatística descritiva e à análise de conteúdo temática. A estratégia mais utilizada foi fuga e esquiva, demonstrando que os familiares preferiam não enfrentar a situação. A segunda estratégia mais usada foi suporte social, ratificada ao afirmarem que conversaram com outras pessoas e profissionais buscando informações sobre o problema, e por aceitarem positivamente o apoio recebido. A terceira foi resolução de problemas, representada pela atitude em assumir o cuidado, seja pelo forte vínculo afetivo ou pelo sentimento de responsabilidade já estabelecido antes da doença. As famílias empregaram estratégias de enfrentamento com intensidades diferentes, porém indicando envolvimento e grande participação no cuidado ao doente.Universidade Federal de São Paulo (UNIFESP)aff2Universidade Estadual de MaringáUEMUNIFESPSciEL

A model for describing and maximising Security Knowledge Sharing to enhance security awareness

Employees play a crucial role in enhancing information security in the workplace, and this requires everyone having the requisite security knowledge and know-how. To maximise knowledge levels, organisations should encourage and facilitate Security Knowledge Sharing (SKS) between employees. To maximise sharing, we need first to understand the mechanisms whereby such sharing takes place and then to encourage and engender such sharing. A study was carried out to test the applicability of Transactive Memory Systems Theory in describing knowledge sharing in this context, which confirmed its applicability in this domain. To encourage security knowledge sharing, the harnessing of Self-Determination Theory was proposed— satisfying employee autonomy, relatedness and competence needs to maximise sharing. Such sharing is required to improve and enhance employee security awareness across organisations. We propose a model to describe the mechanisms for such sharing as well as the means by which it can be encouraged

Zinc/copper imbalance reflects immune dysfunction in human leishmaniasis: an ex vivo and in vitro study

BACKGROUND: The process of elimination of intracellular pathogens, such as Leishmania, requires a Th1 type immune response, whereas a dominant Th2 response leads to exacerbated disease. Experimental human zinc deficiency decreases Th1 but not Th2 immune response. We investigated if zinc and copper levels differ in different clinical forms of leishmaniasis, and if these trace metals might be involved in the immune response towards the parasite. METHODS: Blood was collected from 31 patients with either localized cutaneous (LCL), mucosal (ML) or visceral (VL) leishmaniasis, as well as from 25 controls from endemic and non-endemic areas. Anti-Leishmania humoral and cellular immune response were evaluated by quantifying specific plasma IgG, lymphoproliferation and cytokine production, respectively. Plasma levels of Cu and Zn were quantified by atomic absorption spectrophotometry. RESULTS: A significant decrease in plasma Zn was observed in all three patient groups (p < 0.01 for LCL and ML, p < 0.001 for VL), as compared to controls, but only VL (7/10) and ML (1/7) patients displayed overt Zn deficiency. Plasma Cu was increased in LCL and VL (p < 0.001) but not in ML, and was strongly correlated to anti-Leishmania IgG (Spearman r = 0.65, p = 0.0028). Cu/Zn ratios were highest in patients with deficient cellular (VL<<LCL<ML) and exacerbated humoral (VL>LCL>ML) immune response. Ex vivo production of parasite-induced IFN-γ was negatively correlated to plasma Cu levels in LCL (r = -0.57, p = 0.01). In vitro, increased Cu levels inhibited IFN-γ production. CONCLUSIONS: 1. Zn deficiency in VL and ML indicate possible therapeutic administration of Zn in these severe forms of leishmaniasis. 2. Plasma Cu positively correlates to humoral immune response across patient groups. 3. Environmentally or genetically determined increases in Cu levels might augment susceptibility to infection with intracellular pathogens, by causing a decrease in IFN-γ production