Role of PII proteins in nitrogen fixation control of Herbaspirillum seropedicae strain SmR1

<p>Abstract</p> <p>Background</p> <p>The PII protein family comprises homotrimeric proteins which act as transducers of the cellular nitrogen and carbon status in prokaryotes and plants. In <it>Herbaspirillum seropedicae</it>, two PII-like proteins (GlnB and GlnK), encoded by the genes <it>glnB </it>and <it>glnK</it>, were identified. The <it>glnB </it>gene is monocistronic and its expression is constitutive, while <it>glnK </it>is located in the <it>nlmAglnKamtB </it>operon and is expressed under nitrogen-limiting conditions.</p> <p>Results</p> <p>In order to determine the involvement of the <it>H. seropedicae glnB </it>and <it>glnK </it>gene products in nitrogen fixation, a series of mutant strains were constructed and characterized. The <it>glnK^-</it>mutants were deficient in nitrogen fixation and they were complemented by plasmids expressing the GlnK protein or an N-truncated form of NifA. The nitrogenase post-translational control by ammonium was studied and the results showed that the <it>glnK </it>mutant is partially defective in nitrogenase inactivation upon addition of ammonium while the <it>glnB </it>mutant has a wild-type phenotype.</p> <p>Conclusions</p> <p>Our results indicate that GlnK is mainly responsible for NifA activity regulation and ammonium-dependent post-translational regulation of nitrogenase in <it>H. seropedicae</it>.</p

Synthetic thiosemicarbazones as a new class of Mycobacterium tuberculosis protein tyrosine phosphatase A inhibitors.

Abstract Mycobacterium tuberculosis secretes two protein tyrosine phosphatases as virulence factors, PtpA and PtpB. Inhibition studies of these enzymes have shown significant attenuation of the M. tuberculosis growth in vivo. As PtpA mediates many effects on the regulation of host signaling ensuring the intracellular survival of the bacterium we report, for the first time, thiosemicarbazones as potential novel class of PtpA inhibitors. Several compounds were synthesized and biologically evaluated, revealing interesting results. Enzyme kinetic assays showed that compounds 5, 9 and 18 are non-competitive inhibitors of PtpA, with Ki values ranging from 1.2 to 5.6 µM. Modeling studies clarified the structure-activity relationships observed in vitro and indicated a possible allosteric binding site in PtpA structure. To the best of our knowledge, this is the first disclosure of potent non-competitive inhibitors of PtpA with great potential for future studies and development of analogues

Effects of restraint stress on the daily rhythm of hydrolysis of adenine nucleotides in rat serum

<p>Abstract</p> <p>Background</p> <p>Adenosine 5-triphosphate (ATP) and its breakdown products ADP and adenosine can act as extracellular messengers in a range of biological processes. Extracellular adenine nucleotides are metabolized by a number of enzymes including NTPDases and 5'-nucleotidase, which are considered to be the major regulators of purinergic signaling in the blood. Previous work by our group demonstrated that ATPase and ADPase activities in rat serum exhibit a 24-h temporal pattern, with higher enzyme activity during the dark (activity) phase. It was found that stress can cause disruptions in biological circadian rhythms and in the cardiovascular system. Therefore, the aim of the present study was to examine the influence of acute stress exposure upon temporal patterns of NTPDase and 5-nucleotidase enzyme activities in rat blood serum.</p> <p>Methods</p> <p>Adult male Wistar rats were divided into 4 groups: ZT0, ZT6, ZT12 and ZT18. Each group was subdivided in 4 groups: control, immediately, 6 h and 24 h after one hour of restraint stress. ATP, ADP and AMP hydrolysis were assayed in the serum.</p> <p>Results</p> <p>All stressed groups showed significant decreases in all enzyme activities at ZT 12 and ZT 18 when compared with control.</p> <p>Conclusion</p> <p>Acute stress provokes a decrease in nucleotidase activities dependent on the time that this stress occurs and this effect appears to persist for at least 24 hours. Stress can change levels of nucleotides, related to increased frequency of cardiovascular events during the activity phase. Altered levels of nucleotides in serum may be involved in cardiovascular events more frequent during the activity phase in mammals, and with their etiology linked to stress.</p

Fatores associados a desfechos desfavoráveis após trauma craniano leve pediátrico em um centro de referência da região norte de Minas Gerais

Study Design: Prospective cohort. Objective: To describe clinical and demographic characteristics of a sample of children with HI referred for acute care in a referral center of the north region of Minas Gerais, Brazil, and assess clinical and radiological markers associated with unfavorable outcomes. Methodology: All children between the ages 0 to 14 years referred with head injury from February to September 2011 were included in this study. Socio-demographic and clinical data were collected at the moment of the initial assessment under informed consent. The patients were also reassessed via telephone calls after 7 and 91 days. Results: A total of 77 patients were included in this study. The mean age was 3.9 years with a standard deviation of 3.76 years. Falls and bicycle collisions were the main mechanisms of trauma. The most relevant clinical marker associated with unfavorable outcomes at 7 days was the parental perception of unusual behavior (Odds Ratio = 11.33; 95% confidence interval: 1.38-93.13; p = 0.02). Computer tomography scan abnormalities were associated with both unfavorable outcomes at 7 days (p=0.03) and at 91 days (p=0.02). Conclusions: The peculiar aspects of head injuries in a Brazilian population were described in this study. It was also found that unusual behavior and abnormalities on CT scan are factors that predict unfavorable outcomes in children with mild HI in this population.Modelo do Estudo: Coorte prospectivo. Objetivo do Estudo: Descrever características clínicas e demográficas de uma amostra de crianças encaminhadas por traumatismo craniano em um centro de referência na região norte de Minas Gerais e avaliar marcadores clínicos e radiológicos associados a desfechos desfavoráveis. Metodologia: Foram incluídas neste estudo todas as crianças entre 0 e 14 anos atendidas com traumatismo craniano de fevereiro a setembro de 2011. Dados sócio demográficos e clínicos foram coletados no momento da avaliação inicial sob consentimento informado. Os pacientes também foram reavaliados por telefone após 7 e 91 dias. Resultados: Um total de 77 pacientes foi incluído neste estudo. A idade média foi de 3,9 anos, com desvio padrão de 3,76 anos. Quedas e colisões de bicicleta foram os principais mecanismos de trauma. O marcador clínico mais relevante associado a desfechos desfavoráveis com 7 dias foi a percepção pelos pais de comportamento anormal (Odds Ratio = 11,3; intervalo de confiança de 95%: 1,38-93,13; p = 0,02). Alterações na Tomografia Computadorizada foram associadas tanto a desfechos desfavoráveis após 7 dias (p=0,03) como após 91 dias (p=0,02). Conclusões: Os aspectos peculiares do traumatismo craniano em uma população brasileira são descritos neste estudo. Encontrou-se, ainda, que um comportamento anormal e alterações na TC são fatores que predizem desfechos desfavoráveis em crianças com traumatismo craniano leve nessa população

Heterotopic autotransplantation of ovarian tissue in a large animal model: Effects of cooling and VEGF.

Heterotopic and orthotopic ovarian tissue autotransplantation techniques, currently used in humans, will become promising alternative methods for fertility preservation in domestic and wild animals. Thus, this study describes for the first time the efficiency of a heterotopic ovarian tissue autotransplantation technique in a large livestock species (i.e., horses) after ovarian fragments were exposed or not to a cooling process (4°C/24 h) and/or VEGF before grafting. Ovarian fragments were collected in vivo via an ultrasound-guided biopsy pick-up method and surgically autografted in a subcutaneous site in both sides of the neck in each mare. The blood flow perfusion at the transplantation site was monitored at days 2, 4, 6, and 7 post-grafting using color-Doppler ultrasonography. Ovarian grafts were recovered 7 days post-transplantation and subjected to histological analyses. The exposure of the ovarian fragments to VEGF before grafting was not beneficial to the quality of the tissue; however, the cooling process of the fragments reduced the acute hyperemia post-grafting. Cooled grafts compared with non-cooled grafts contained similar values for normal and developing preantral follicles, vessel density, and stromal cell apoptosis; lower collagen type III fibers and follicular density; and higher stromal cell density, AgNOR, and collagen type I fibers. In conclusion, VEGF exposure before autotransplantation did not improve the quality of grafted tissues. However, cooling ovarian tissue for at least 24 h before grafting can be beneficial because satisfactory rates of follicle survival and development, stromal cell survival and proliferation, as well as vessel density, were obtained

Estudo de acessibilidade em habitação econômica na cidade de João Pessoa/PB / Study of accessibility in economic housing in the city of João Pessoa/PB

Este artigo apesenta uma possível abordagem sobre a acessibilidade na arquitetura, análise e avaliação, como desdobramento do projeto de extensão: “Readequação Habitacional à Pessoas com Deficiência na Cidade de João Pessoa-PB”. O projeto, que vem sendo desenvolvido no Centro Universitário de João Pessoa- UNIPÊ, avalia os limites e possibilidades do espaço construído no que se refere à adaptação de uma habitação a um usuário específico que adquiriu deficiência motora. Os procedimentos metodológicos aplicados no desenvolvimento do trabalho consistem em selecionar o paciente que tenha adquirido deficiência e que utilize os recursos terapêuticos oferecidos pela Clínica Escola de Fisioterapia do UNIPÊ, buscando compreender as limitações desses pacientes, aplicando as normas técnicas específicas ao caso e fornecendo ajuda técnica para uma possível adequação do ambiente residencial. O trabalho desenvolvido foi auxiliado pelos levantamentos espaciais e fotográficos, e da observação entre os dados antropométricos e sua relação com a habitação. Ao final, ressaltamos as dificuldades em tratar de ambientes construídos tão limitados – espaços diminutos de habitação econômica – além da importância de um diagnóstico de interação espaço e usuário

Histomorphometric and immunohistochemical analysis of infectious agents, T-cell subpopulations and inflammatory adhesion molecules in placentas from HIV-seropositive pregnant women

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to compare histomorphometric changes and the results of immunohistochemical tests for VCAM, ICAM-1, CD4 and CD8 in normal placentas from HIV-seropositive pregnant women.</p> <p>Methods</p> <p>Samples of normal placentas were divided into 2 groups: healthy HIV-seronegative pregnant women (control group = C = 60) and HIV-seropositive women (experimental group = E = 57). Conventional histological sections were submitted to morphometric analysis and evaluated in terms of the immunohistochemical expression of ICAM-1, VCAM, CD4 and CD8.</p> <p>Results</p> <p>The villi in group E were smaller than those in group C. The median for the CD8+ T cell count was higher in group E than in group C (p = 0.03). Immunohistochemical expression of ICAM-1 was observed in 57% of the cases in group E, compared with 21% of those in group C (p = 0.001). There was no difference in VCAM expression or CD4+ cell counts between groups and no correlation between the data for antiretroviral therapy and morphometric or immunohistochemical data.</p> <p>Conclusions</p> <p>The morphometric data showed that placentas of HIV-seropositive pregnant women tend to have smaller villi than those of seronegative women. In addition, immunohistochemical testing for infectious agents helped to identify cases that were positive for microorganisms (6/112) that routine pathological examination had failed to detect. The anti-p24 antibody had a limited ability to detect HIV viral protein in this study (2/57). Correlation of immunohistochemical expression of CD8+ T cells and ICAM-1 with the presence of HIV in the placenta revealed that those expressions can act as biomarkers of inflammatory changes. There was no correlation between the data for antiretroviral therapy and morphometric or immunohistochemical data.</p