Coordinate control of virulence gene expression in Francisella tularensis

Francisella tularensis is a Gram-negative, intracellular pathogen and the causative agent of tularemia. Due to its low infectious dose, ability to cause potentially fatal disease, and ability to be easily aerosolized, several countries have developed F. tularensis as a potential bioweapon. Three proteins, MglA, SspA, and PigR, and the small molecule guanosine tetraphosphate (ppGpp), are transcription factors critical for the virulence of this organism. These regulators function coordinately to positively regulate the expression of genes present on the Francisella pathogenicity island, as well as many other genes that are required for the virulence of this organism. MglA and SspA form a complex that associates with RNA polymerase (RNAP); the interaction between the MglA-SspA complex and RNAP is thought to be critical for MglA and SspA to regulate gene expression. PigR, a putative DNA-binding protein, associates with the RNAP-associated MglA-SspA complex and may stabilize the binding of RNAP at regulated promoters. The interaction between the MglA-SspA complex and PigR in F. tularensis has been shown to be promoted by ppGpp. A direct interaction between the MglA-SspA complex and PigR had previously been found using a modified version of an E. coli two-hybrid assay, referred to as the bridge-hybrid assay, that permits the detection of interactions between a protein of interest and a protein complex. However, the role of this direct interaction in controlling gene expression in F. tularensis had not been investigated. Conflicting reports in the literature over the ability of PigR to interact with the MglA-SspA complex led to differing models of how PigR regulates virulence gene expression in F. tularensis. To address the importance of the interaction between the MglA-SspA complex and PigR in regulating gene expression, we used a combination of genetic approaches to identify mutants of either MglA or SspA that are specifically defective for interaction with PigR. The identified mutants of MglA and SspA were unable to functionally substitute for MglA or SspA, respectively, and were unable to promote expression of MglA- and SspA- regulated genes in F. tularensis. These results indicate that the interaction between the MglA-SspA complex and PigR is critical for expression of virulence genes in F. tularensis. Our work also identified a surface on the MglA-SspA complex that is important for the interaction with PigR and which may constitute a binding site for PigR. The small molecule ppGpp has previously been shown to promote the interaction between the MglA-SspA complex and PigR in F. tularensis. It is unknown if ppGpp directly or indirectly promotes this interaction. We determined that ppGpp is required to detect an interaction between the MglA-SspA complex and PigR in the E. coli bridge-hybrid assay, indicating that ppGpp is either directly involved in promoting this interaction or works through an indirect mechanism that is conserved between F. tularensis and E. coli. One potential conserved mechanism through which ppGpp may be influencing the interaction between the MglA-SspA complex and PigR is through regulation of the levels of the molecule polyphosphate. However, we determined that polyphosphate is not required in order for the MglA-SspA complex and PigR to detectably interact with one another in the E. coli bridge-hybrid assay. Furthermore, analysis of the role of polyphosphate in gene expression in F. tularensis revealed that polyphosphate is a negative regulator of virulence gene expression.Medical Science

Compensatory T Cell Responses in IRG-Deficient Mice Prevent Sustained Chlamydia trachomatis Infections

The obligate intracellular pathogen Chlamydia trachomatis is the most common cause of bacterial sexually transmitted diseases in the United States. In women C. trachomatis can establish persistent genital infections that lead to pelvic inflammatory disease and sterility. In contrast to natural infections in humans, experimentally induced infections with C. trachomatis in mice are rapidly cleared. The cytokine interferon-γ (IFNγ) plays a critical role in the clearance of C. trachomatis infections in mice. Because IFNγ induces an antimicrobial defense system in mice but not in humans that is composed of a large family of Immunity Related GTPases (IRGs), we questioned whether mice deficient in IRG immunity would develop persistent infections with C. trachomatis as observed in human patients. We found that IRG-deficient Irgm1/m3(-/-) mice transiently develop high bacterial burden post intrauterine infection, but subsequently clear the infection more efficiently than wildtype mice. We show that the delayed but highly effective clearance of intrauterine C. trachomatis infections in Irgm1/m3(-/-) mice is dependent on an exacerbated CD4+ T cell response. These findings indicate that the absence of the predominant murine innate effector mechanism restricting C. trachomatis growth inside epithelial cells results in a compensatory adaptive immune response, which is at least in part driven by CD4+ T cells and prevents the establishment of a persistent infection in mice

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Demonstrating actions to a robot: How na\ive users adapt to a robot’s replication of goal and manner-oriented actions

Vollmer A-L, Mühlig M, Rohlfing K, Wrede B, Cangelosi A. Demonstrating actions to a robot: How na\ive users adapt to a robot’s replication of goal and manner-oriented actions. In: Fernández R, Isard A, eds. SEMDIAL 2013 DialDam. Proceedings of the 17th Workshop on the Semantics and Pragmatics of Dialogue : Amsterdam, 16-18 December 2013. Proceedings SemDial. Amsterdam: Univ. of Amsterdam; 2013: 240-242

Screening for Diabetes in an Outpatient Clinic Population

BACKGROUND: Opportunistic disease screening is the routine, asymptomatic disease screening of patients at the time of a physician encounter for other reasons. While the prevalence of unrecognized diabetes in community populations is well known, the prevalence in clinical populations is unknown. OBJECTIVE: To describe the prevalence, predictors, and clinical severity of unrecognized diabetes among outpatients at a major medical center. DESIGN AND SETTING: A cross-sectional observational study at the Durham Veterans Affairs Medical Center. SUBJECTS: Outpatients without recognized diabetes (N = 1,253). METHODS: We screened patients for diabetes by using an initial random Hemoglobin A1c (HbA1c) measurement, and then obtaining follow-up fasting plasma glucose (FPG) for all subjects with HbA1c ≥6.0%. A case of unrecognized diabetes was defined as either HbA1c ≥7.0% or FPG ≥7 mmol/L (126 mg/dL). Height and weight were obtained for all subjects. We also obtained resting blood pressure, fasting lipids, and urine protein in subjects with HbA1c ≥6.0%. RESULTS: The prevalence of unrecognized diabetes was 4.5% (95% confidence interval [CI], 3.4 to 5.7). Factors associated with unrecognized diabetes were the diagnosis of hypertension (adjusted odds ratio [OR], 2.5; P = .004), weight >120% of ideal (adjusted OR, 2.2; P = .02), and history of a parent or sibling with diabetes (adjusted OR, 1.7; P = .06). Having a primary care provider did not raise or lower the risk for unrecognized diabetes (P = .73). Based on the new diagnosis, most patients (61%) found to have diabetes required a change in treatment either of their blood sugar or comorbid hypertension or hyperlipidemia in order to achieve targets recommended in published treatment guidelines. Patients reporting a primary care provider were no less likely to require a change in treatment (P = .20). CONCLUSIONS: If diabetes screening is an effective intervention, opportunistic screening for diabetes may be the preferred method for screening, because there is substantial potential for case-finding in a medical center outpatient setting. A majority of patients with diabetes diagnosed at opportunistic screening will require a change in treatment of blood sugar, blood pressure, or lipids to receive optimal care

Carcinomes canalaires in situ du sein (influence de l'âge sur les critères diagnostiques, thérapeutiques et pronostiques)

Introduction : Les patientes de moins de 40 ans au diagnostic d'un carcinome canalaire in situ semblent avoir un pronostic plus sombre que les patientes plus âgées. Cependant l'impact de l'âge sur le devenir reste controversé. Matériel et méthodes : A partir d'une série rétrospective de 912 patientes traitées à l'Institut Bergonié entre 1971 et 2001, nous avons étudié l'influence de l'âge sur les critères diagnostiques, histologiques, thérapeutiques et pronostiques des carcinomes canalaires in situ. Résultats : Les CCIS ont plus fréquemment une expression clinique chez les femmes de moins de 40 ans que chez les patientes plus âgées. Parallèlement, chez les femmes jeunes, les lésions semblent être de meilleur pronostic d'un point de vue histologique sans que la différence soit significative. Les facteurs pronostiques retrouvés dans notre étude, en analyse uni comme multivariée, sont l'âge de moins de 40 ans, le type de traitement et l'état des berges d'exérèse. Le jeune âge (RR =1,82 IC [1,025 - 3,24] p = 0,041) et le traitement conservateur (RR = 6,057 IC [2,68 - 13,64] p < 10 puis -3 pour les marges non saines) sont les seuls de risque de récidive dans notre série. Conclusion : L'âge de moins de 40 ans apparaît comme un facteur de risque de récidive indépendamment des caractéristiques cliniques et hostologiques. L'autre facteur pronostique retrouvé dans notre étude est le traitement chirurgical initial, surtout un cas de berges envahies. Une chirurgie initiale optimale avec des marges de résection particulièrement larges, apparaît indispensable chez les femmes jeunes qui ont un risque de récidive augmenté.FORT-DE-FRANCE-CHRU-BU (972332102) / SudocBORDEAUX2-BU Santé (330632101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF