Inhibition of glutamine synthetase by phosphinothricin leads to transcriptome reprograming in root nodules of Medicago truncatula

Glutamine synthetase (GS) is a vital enzyme for the assimilation of ammonia into amino acids in higher plants. In legumes, GS plays a crucial role in the assimilation of the ammonium released by nitrogen-fixing bacteria in root nodules, constituting an important metabolic knob controlling the nitrogen (N) assimilatory pathways. To identify new regulators of nodule metabolism, we profiled the transcriptome of Medicago truncatula nodules impaired in N assimilation by specifically inhibiting GS activity using phosphinothricin (PPT). Global transcript expression of nodules collected before and after PPT addition (4, 8, and 24 h) was assessed using Affymetrix M. truncatula GeneChip arrays. Hundreds of genes were regulated at the three time points, illustrating the dramatic alterations in cell metabolism that are imposed on the nodules upon GS inhibition. The data indicate that GS inhibition triggers a fast plant defense response, induces premature nodule senescence, and promotes loss of root nodule identity. Consecutive metabolic changes were identified at the three time points analyzed. The results point to a fast repression of asparagine synthesis and of the glycolytic pathway and to the synthesis of glutamate via reactions alternative to the GS/GOGAT cycle. Several genes potentially involved in the molecular surveillance for internal organic N availability are identified and a number of transporters potentially important for nodule functioning are pinpointed. The data provided by this study contributes to the mapping of regulatory and metabolic networks involved in root nodule functioning and highlight candidate modulators for functional analysis.

Bacterial translocation in rats nonfunctioning diverted distal colon

To investigate whether the alterations of the diverted colon segment mucosa, evidenced in fecal colitis, would be able to alter Bacterial Translocation (BT). Methods: Sixty-two Wistar male rats ranging from 220 to 320 grams of weight, were divided in two groups: A (Colostomy) and B (Control), with 31 animals each one. In group A, all animals underwent end colostomy, one stoma, in ascending colon; and in the 70th POD was injected in five rats, by rectal route – diverted segment - 2ml of a 0.9% saline solution in animals (A1 subgroup); in eight it was inoculated, by rectal route, 2ml of a solution containing Escherichia coli ATCC 25922 (American Type Culture Collection), in a concentration of 108 Colony Forming Unit for milliliters (CFU/ml) - A2 Subgroup; in ten animals the same solution of E. coli was inoculated, in a concentration of 1011 CFU/ml (A3 Subgroup); and in eight it was collected part of the mucus found in the diverted distal colonic segment for neutral sugars and total proteins dosage (A4 subgroup). The animals from the group B underwent the same procedures of group A, but with differences in the colostomy confection. In rats from subgroups A1, A2, A3, B1, B2, and B3 2ml of blood were aspirated from the heart, and fragments from mesenteric lymphatic nodule, liver, spleen, lung and kidney taken for microbiological analysis, after their death. This analysis consisted of evidencing the presence of E. coli ATCC 25922 CFU. Mann-Whitney and ANOVA Tests were applied as analytic techniques for association of variables. Results: The occurrence of BT was evidenced only in those animals in which inoculated concentration of E. coli ATCC 25922, reached levels of 1011CFU/ml, i.e. in Subgroups A3 and B3, although, being significantly greater (80%) in those animals without colostomy (subgroup B3) when compared to the ones with colostomy (20%) from the subgroup A3 (P <0.05). Lung, liver and mesenteric lymphatic nodules were the tissues with larger percentile of bacterial recovery, so much in subgroup A3, as in B3. Blood culture was considered positive in 60% of the animals from subgroup B3 and in 10% of those from subgroup A3 (p <0.05). There was greater concentration of neutral sugars, in subgroup A4 - mean 27.3mg/ml -, than in subgroup B4 - mean 8.4mg/ml - (P <0.05). Conclusion: The modifications in the architecture of intestinal mucosa in colitis following fecal diversion can cause alterations in the intestinal barrier, but it does not necessarily lead to an increased frequency of BT

Postoperative Treatment in a Patient After Hemithyroidectomy: the Therapeutic Challenges of a Hidden Thyrotropinoma

Objectives: We report the unusual case of a patient with a thyrotropinoma, discovered after a hemithyroidectomy for a suspicious thyroid nodule, and its therapeutic challenges. Materials and methods: In a patient who underwent hemithyroidectomy for cold thyroid nodule, hyperthyroid symptoms persisted, despite stopping levothyroxine treatment. Further investigation was carried out through the following laboratory tests: thyroid-stimulating hormone (TSH) test; free thyroxine (fT4) test; and the thyrotropin releasing hormone (TRH) test. A pituitary magnetic resonance imaging (MRI) scan and genetic analysis was also carried out. The test results confirmed the diagnosis of a thyrotropinoma. Results: Treatment with long-acting somatostatin analogues normalised thyroid hormones and symptoms of hyperthyroidism. Conclusion: The diagnostic approach to the thyroid nodule should include a detailed clinical and biochemical examination. Initial biochemical evaluation by TSH alone does not allow detecting inappropriate TSH secretion that may increase the risk of thyroid malignancy. In case of a thyrotropinoma, the ideal treatment consists of combined care of central and peripheral thyroid disease.

Sialadenoma Papilliferum with Inverted Pattern in a Young Patient: A Case Report

BACKGROUND: Sialadenoma papilliferum (SP) is a rare, benign neoplasm of salivary gland origin which manifests as an exophytic papillary excrescence of the mucosa. Indeed, SP is both an exophytic proliferation of papillary stratified squamous epithelium above the mucosal surface and an endophytic salivary ductal proliferation beneath the mucosa. It arises predominantly in minor salivary glands and usually affects patients in the age range of 32-87 years, with reports in young patients being exceedingly rare.

Threatened by mining, polymetallic nodules are required to preserve abyssal epifauna

Polymetallic nodule mining at abyssal depths in the Clarion Clipperton Fracture Zone (Eastern Central Pacific) will impact one of the most remote and least known environments on Earth. Since vast areas are being targeted by concession holders for future mining, large-scale effects of these activities are expected. Hence, insight into the fauna associated with nodules is crucial to support effective environmental management. In this study video surveys were used to compare the epifauna from sites with contrasting nodule coverage in four license areas. Results showed that epifaunal densities are more than two times higher at dense nodule coverage (>25 versus ≤10 individuals per 100 m2), and that taxa such as alcyonacean and antipatharian corals are virtually absent from nodule-free areas. Furthermore, surveys conducted along tracks from trawling or experimental mining simulations up to 37 years old, suggest that the removal of epifauna is almost complete and that its full recovery is slow. By highlighting the importance of nodules for the epifaunal biodiversity of this abyssal area, we urge for cautious consideration of the criteria for determining future preservation zones.

ESR/ERS white paper on lung cancer screening

Lung cancer is the most frequently fatal cancer, with poor survival once the disease is advanced. Annual low-dose computed tomography has shown a survival benefit in screening individuals at high risk for lung cancer. Based on the available evidence, the European Society of Radiology and the European Respiratory Society recommend lung cancer screening in comprehensive, quality-assured, longitudinal programmes within a clinical trial or in routine clinical practice at certified multidisciplinary medical centres. Minimum requirements include: standardised operating procedures for low-dose image acquisition, computer-assisted nodule evaluation, and positive screening results and their management; inclusion/exclusion criteria; expectation management; and smoking cessation programmes. Further refinements are recommended to increase quality, outcome and cost-effectiveness of lung cancer screening: inclusion of risk models, reduction of effective radiation dose, computer-assisted volumetric measurements and assessment of comorbidities (chronic obstructive pulmonary disease and vascular calcification). All these requirements should be adjusted to the regional infrastructure and healthcare system, in order to exactly define eligibility using a risk model, nodule management and a quality assurance plan. The establishment of a central registry, including a biobank and an image bank, and preferably on a European level, is strongly encouraged. Key points: • Lung cancer screening using low dose computed tomography reduces mortality. • Leading US medical societies recommend large scale screening for high-risk individuals. • There are no lung cancer screening recommendations or reimbursed screening programmes in Europe as of yet. • The European Society of Radiology and the European Respiratory Society recommend lung cancer screening within a clinical trial or in routine clinical practice at certified multidisciplinary medical centres. • High risk, eligible individuals should be enrolled in comprehensive, quality-controlled longitudinal programmes.

Development of hydroxyapatite-based nanomaterials to enhance biological response of osteoblast cells for clinical application

Purpose: To develop a novel chitosan/gelatin-hydroxyapatite (CGHaP) microspheres for evaluating the biological response of pre-osteoblast cells. Methods: The microsphere was prepared by water-in-oil emulsion method. Cell proliferation was studied using AlamarBlue colorimetric assay and DAPI staining while alkaline phosphatase assay was carried out by colorimetric assay method. Chitosan microspheres as well as chitosan-hydroxyapatite microspheres was prepared and tested for biological response from MC3T3-E1 cell line. Results: The results showed that CGHaP promotes MC3T3-E1 cell proliferation and spread on the surface of microspheres. The cells were clustered with more actin filaments and well-linked with neighbouring cells or adjacent cells when cultured in CGHaP microspheres whereas fewer cells were spread on chitosan (CH) microspheres. CGHaP microspheres significantly (p < 0.05) promoted cell attachment, proliferation and extracellular matrix mineralization. CGHaP microspheres presented significantly (p < 0.02) higher calcium deposition (0.5 ng) than CH microspheres (0.28 ng). Specifically, CGHaP microspheres exhibited high ALP activity (8 units; 2-fold) compared to CH with 3 units, after 7 days of incubation. The results suggest that CGHaP possesses a great ability to facilitate bone ingrowth formation and possibility of good osteointegration in vivo. Conclusion: The nanomaterial enhances the proliferation of pre-osteoblast cells in tissue engineering microspheres. The outcome of this study may have a major impact on the development of novel nanomaterials for bone tissue engineering.

Uso de espectrometria de massa por ionização e dessorção a laser assistida por matriz : tempo de voo (MALDI-TOF MS) para formação de bibliotecas e caracterização da ocupação nodular em soja por estirpes de Bradyrhizobium

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Biologia Microbiana, 2016.

The Sinorhizobium meliloti EmrR Regulator Is Required for Efficient Colonization of Medicago sativa Root Nodules

The nitrogen-fixing bacterium Sinorhizobium meliloti must adapt to diverse conditions encountered during its symbiosis with leguminous plants. We characterized a new symbiotically relevant gene, emrR (SMc03169), whose product belongs to the TetR family of repressors and is divergently transcribed from emrAB genes encoding a putative major facilitator superfamily-type efflux pump. An emrR deletion mutant produced more succinoglycan, displayed increased cell-wall permeability, and exhibited higher tolerance to heat shock. It also showed lower tolerance to acidic conditions, a reduced production of siderophores, and lower motility and biofilm formation. The simultaneous deletion of emrA and emrR genes restored the mentioned traits to the wild-type phenotype, except for survival under heat shock, which was lower than that displayed by the wild-type strain. Furthermore, the ΔemrR mutant as well as the double ΔemrAR mutant was impaired in symbiosis with Medicago sativa; it formed fewer nodules and competed poorly with the wild-type strain for nodule colonization. Expression profiling of the ΔemrR mutant showed decreased expression of genes involved in Nod-factor and rhizobactin biosynthesis and in stress responses. Expression of genes directing the biosynthesis of succinoglycan and other polysaccharides were increased. EmrR may therefore be involved in a regulatory network targeting membrane and cell wall modifications in preparation for colonization of root hairs during symbiosis.

The Influence of Healed Intrablock Rockmass Structure on the Behaviour of Deep Excavations in Complex Rockmasses

Conventional rockmass characterization and analysis methods for geotechnical assessment in mining, civil tunnelling, and other excavations consider only the intact rock properties and the discrete fractures that are present and form blocks within rockmasses. Field logging and classification protocols are based on historically useful but highly simplified design techniques, including direct empirical design and empirical strength assessment for simplified ground reaction and support analysis. As modern underground excavations go deeper and enter into more high stress environments with complex excavation geometries and associated stress paths, healed structures within initially intact rock blocks such as sedimentary nodule boundaries and hydrothermal veins, veinlets and stockwork (termed intrablock structure) are having an increasing influence on rockmass behaviour and should be included in modern geotechnical design. Due to the reliance on geotechnical classification methods which predate computer aided analysis, these complexities are ignored in conventional design. Given the comparatively complex, sophisticated and powerful numerical simulation and analysis techniques now practically available to the geotechnical engineer, this research is driven by the need for enhanced characterization of intrablock structure for application to numerical methods. Intrablock structure governs stress-driven behaviour at depth, gravity driven disintegration for large shallow spans, and controls ultimate fragmentation. This research addresses the characterization of intrablock structure and the understanding of its behaviour at laboratory testing and excavation scales, and presents new methodologies and tools to incorporate intrablock structure into geotechnical design practice. A new field characterization tool, the Composite Geological Strength Index, is used for outcrop or excavation face evaluation and provides direct input to continuum numerical models with implicit rockmass structure. A brittle overbreak estimation tool for complex rockmasses is developed using field observations. New methods to evaluate geometrical and mechanical properties of intrablock structure are developed. Finally, laboratory direct shear testing protocols for interblock structure are critically evaluated and extended to intrablock structure for the purpose of determining input parameters for numerical models with explicit structure.

Nódulo pulmonar solitario con calcificaciones en ‘‘palomitas de maíz’’

SIN FINANCIACIÓN