212 research outputs found

    Study of Distribution and Asymmetry of Solar Active Prominences During Solar Cycle 23

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    In this paper we present the results of a study of the spatial distribution and asymmetry of solar active prominences (SAP) for the period 1996-2007 (solar cycle 23). For more meaningful statistical analysis we have analysed the distribution and asymmetry of SAP in two subdivisions viz. Group1 (ADF, APR, DSF, CRN, CAP) and Group2 (AFS, ASR, BSD, BSL, DSD, SPY, LPS). The north-south (N-S) latitudinal distribution shows that the SAP events are most prolific in the 21-30degree slice in the northern and southern hemispheres and east-west (E-W) longitudinal distribution study shows that the SAP events are most prolific (best visible) in the 81-90degree slice in the eastern and western hemispheres. It has been found that the SAP activity during this cycle is low compared to previous solar cycles. The present study indicates that during the rising phase of the cycle the number of SAP events were roughly equal on the north and south hemispheres. However, activity on the southern hemisphere has been dominant since 1999. Our statistical study shows that the N-S asymmetry is more significant then the E-W asymmetry.Comment: 21 pages 5 figures; Published online; 02 October, 2009; Solar Physics Journa

    Photospheric Magnetic Field: Relationship Between North-South Asymmetry and Flux Imbalance

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    Photospheric magnetic fields were studied using the Kitt Peak synoptic maps for 1976-2003. Only strong magnetic fields (B>100 G) of the equatorial region were taken into account. The north-south asymmetry of the magnetic fluxes was considered as well as the imbalance between positive and negative fluxes. The north-south asymmetry displays a regular alternation of the dominant hemisphere during the solar cycle: the northern hemisphere dominated in the ascending phase, the southern one in the descending phase during Solar Cycles 21-23. The sign of the imbalance did not change during the 11 years from one polar-field reversal to the next and always coincided with the sign of the Sun's polar magnetic field in the northern hemisphere. The dominant sign of leading sunspots in one of the hemispheres determines the sign of the magnetic-flux imbalance. The sign of the north-south asymmetry of the magnetic fluxes and the sign of the imbalance of the positive and the negative fluxes are related to the quarter of the 22-year magnetic cycle where the magnetic configuration of the Sun remains constant (from the minimum where the sunspot sign changes according to Hale's law to the magnetic-field reversal and from the reversal to the minimum). The sign of the north-south asymmetry for the time interval considered was determined by the phase of the 11-year cycle (before or after the reversal); the sign of the imbalance of the positive and the negative fluxes depends on both the phase of the 11-year cycle and on the parity of the solar cycle. The results obtained demonstrate the connection of the magnetic fields in active regions with the Sun's polar magnetic field in the northern hemisphere.Comment: 24 pages, 12 figures, 2 table

    North-South Distribution of Solar Flares during Cycle 23

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    In this paper, we investigate the spatial distribution of solar flares in the northern and southern hemisphere of the Sun that occurred during the period 1996 to 2003. This period of investigation includes the ascending phase, the maximum and part of descending phase of solar cycle 23. It is revealed that the flare activity during this cycle is low compared to previous solar cycle, indicating the violation of Gnevyshev-Ohl rule. The distribution of flares with respect to heliographic latitudes shows a significant asymmetry between northern and southern hemisphere which is maximum during the minimum phase of the solar cycle. The present study indicates that the activity dominates the northern hemisphere in general during the rising phase of the cycle (1997-2000). The dominance of northern hemisphere is shifted towards the southern hemisphere after the solar maximum in 2000 and remained there in the successive years. Although the annual variations in the asymmetry time series during cycle 23 are quite different from cycle 22, they are comparable to cycle 21.Comment: 6 pages, 2 figures, 1 table; Accepted for the publication in the proceedings of international solar workshop held at ARIES, Nainital, India on "Transient Phenomena on the Sun and Interplanetary Medium" in a special issue of "Journal of Astrophysics and Astronomy (JAA)

    pEPito: a significantly improved non-viral episomal expression vector for mammalian cells

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    <p>Abstract</p> <p>Background</p> <p>The episomal replication of the prototype vector pEPI-1 depends on a transcription unit starting from the constitutively expressed <it>Cytomegalovirus </it>immediate early promoter (CMV-IEP) and directed into a 2000 bp long <it>matrix attachment region sequence </it>(MARS) derived from the human β-interferon gene. The original pEPI-1 vector contains two mammalian transcription units and a total of 305 CpG islands, which are located predominantly within the vector elements necessary for bacterial propagation and known to be counterproductive for persistent long-term transgene expression.</p> <p>Results</p> <p>Here, we report the development of a novel vector pEPito, which is derived from the pEPI-1 plasmid replicon but has considerably improved efficacy both <it>in vitro </it>and <it>in vivo</it>. The pEPito vector is significantly reduced in size, contains only one transcription unit and 60% less CpG motives in comparison to pEPI-1. It exhibits major advantages compared to the original pEPI-1 plasmid, including higher transgene expression levels and increased colony-forming efficiencies <it>in vitro</it>, as well as more persistent transgene expression profiles <it>in vivo</it>. The performance of pEPito-based vectors was further improved by replacing the CMV-IEP with the <it>human CMV enhancer/human elongation factor 1 alpha promoter </it>(hCMV/EF1P) element that is known to be less affected by epigenetic silencing events.</p> <p>Conclusions</p> <p>The novel vector pEPito can be considered suitable as an improved vector for biotechnological applications <it>in vitro </it>and for non-viral gene delivery <it>in vivo</it>.</p

    Varicella Zoster Virus ORF25 Gene Product: An Essential Hub Protein Linking Encapsidation Proteins and the Nuclear Egress Complex

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    Varicella zoster virus (VZV) ORF25 is a 156 amino acid protein belonging to the approximately 40 core proteins that are conserved throughout the Herpesviridae. By analogy to its functional orthologue UL33 in Herpes simplex virus 1 (HSV-1), ORF25 is thought to be a component of the terminase complex. To investigate how cleavage and encapsidation of viral DNA links to the nuclear egress of mature capsids in VZV, we tested 10 VZV proteins that are predicted to be involved in either of the two processes for protein interactions against each other using three independent protein-protein interaction (PPI) detection systems: the yeast-two-hybrid (Y2H) system, a luminescence based MBP pull-down interaction screening assay (LuMPIS), and a bioluminescence resonance energy transfer (BRET) assay. A set of 20 interactions was consistently detected by at least 2 methods and resulted in a dense interaction network between proteins associated in encapsidation and nuclear egress. The results indicate that the terminase complex in VZV consists of ORF25, ORF30, and ORF45/42 and support a model in which both processes are closely linked to each other. Consistent with its role as a central hub for protein interactions, ORF25 is shown to be essential for VZV replication.Fil: Vizoso Pinto, María Guadalupe. Ludwig Maximilians Universitat. Max Von Pettenkofer Institute. Cátedra Virology; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Pothineni, Venkata R.. Ludwig Maximilians Universitat. Max Von Pettenkofer Institute. Cátedra Virology; AlemaniaFil: Haase, Rudolf. Ludwig Maximilians Universitat. Max Von Pettenkofer Institute. Cátedra Virology; AlemaniaFil: Woidy, Mathias. Ludwig Maximilians Universitat; AlemaniaFil: Lotz Havla, Amelie. Ludwig Maximilians Universitat; AlemaniaFil: Gersting, Soren W.. Ludwig Maximilians Universitat; AlemaniaFil: Muntau, Ania C.. Ludwig Maximilians Universitat; AlemaniaFil: Haas, Jurgen. Ludwig Maximilians Universitat. Max Von Pettenkofer Institute. Cátedra Virology; AlemaniaFil: Sommer, Marvin. University of Stanford; Estados UnidosFil: Arvin, Ann M.. University of Stanford; Estados UnidosFil: Baiker, Armin. Bavarian Health and Food Safety Authority; Alemani

    Immunobiotic lactobacilli improve resistance of respiratory epithelial cells to sars-cov-2 infection

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    Previously, we reported that immunomodulatory lactobacilli, nasally administered, benefi-cially regulated the lung antiviral innate immune response induced by Toll-like receptor 3 (TLR3) activation and improved protection against the respiratory pathogens, influenza virus and respiratory syncytial virus in mice. Here, we assessed the immunomodulatory effects of viable and non-viable Lactiplantibacillus plantarum strains in human respiratory epithelial cells (Calu-3 cells) and the capacity of these immunobiotic lactobacilli to reduce their susceptibility to the acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Immunobiotic L. plantarum MPL16 and CRL1506 differentially modulated IFN-β, IL-6, CXCL8, CCL5 and CXCL10 production and IFNAR2, DDX58, Mx1 and OAS1 expression in Calu-3 cells stimulated with the TLR3 agonist poly(I:C). Furthermore, the MPL16 and CRL1506 strains increased the resistance of Calu-3 cells to the challenge with SARS-CoV-2. L. plantarum MPL16 induced these beneficial effects more efficiently than the CRL1506 strain. Of note, neither non-viable MPL16 and CRL1506 strains nor the non-immunomodulatory strains L. plantarum CRL1905 and MPL18 could modify the resistance of Calu-3 cells to SARS-CoV-2 infection or the immune response to poly(I:C) challenge. To date, the potential beneficial effects of immunomodulatory probiotics on SARS-CoV-2 infection and COVID-19 outcome have been extrapolated from studies carried out in the context of other viral pathogens. To the best of our knowledge, this is the first demonstration of the ability of immunomodulatory lactobacilli to positively influence the replication of the new coronavirus. Further mechanistic studies and in vivo experiments in animal models of SARS-CoV-2 infection are necessary to identify specific strains of beneficial immunobiotic lactobacilli like L. plantarum MPL16 or CRL1506 for the prevention or treatment of the COVID-19.Fil: Islam, Md Aminul. Tohoku University; JapónFil: Albarracín, Leonardo Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Tomokiyo, Mikado. Tohoku University; JapónFil: Valdéz, Juan Carlos. Universidad Nacional de Tucumán; ArgentinaFil: Sacur, Jacinto Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Vizoso Pinto, María Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Andrade, Bruno G. N.. No especifíca;Fil: Cuadrat, Rafael R. C.. No especifíca;Fil: Kitazawa, Haruki. Tohoku University; JapónFil: Villena, Julio Cesar. Tohoku University; Japón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin

    A systematic approach for the identification of novel, serologically reactive recombinant Varicella-Zoster Virus (VZV) antigens

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    <p>Abstract</p> <p>Background</p> <p>Varicella-Zoster virus causes chickenpox upon primary infection and shingles after reactivation. Currently available serological tests to detect VZV-specific antibodies are exclusively based on antigens derived from VZV-infected cells.</p> <p>Results</p> <p>We present a systematic approach for the identification of novel, serologically reactive VZV antigens. Therefore, all VZV open reading frames were cloned into a bacterial expression vector and checked for small scale recombinant protein expression. Serum profiling experiments using purified VZV proteins and clinically defined sera in a microarray revealed 5 putative antigens (ORFs 1, 4, 14, 49, and 68). These were rearranged in line format and validated with pre-characterized sera.</p> <p>Conclusions</p> <p>The line assay confirmed the seroreactivity of the identified antigens and revealed its suitability for VZV serodiagnostics comparable to commercially available VZV-ELISA. Recombinant ORF68 (gE) proved to be an antigen for high-confidence determination of VZV serostatus. Furthermore, our data suggest that a serological differentiation between chickenpox and herpes zoster may be possible by analysis of the IgM-portfolio against individual viral antigens.</p

    The Genotype Specific Competitive Ability Does Not Correlate with Infection in Natural Daphnia magna Populations

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    Different evolutionary hypotheses predict a correlation between the fitness of a genotype in the absence of infection and the likelihood to become infected. The cost of resistance hypothesis predicts that resistant genotypes pay a cost of being resistant and are less fit in the absence of parasites. The inbreeding-infection hypothesis predicts that the susceptible individuals are less fit due to inbreeding depression.Here we tested if a host's natural infection status was associated with its fitness. First, we experimentally confirmed that cured but formerly infected Daphnia magna are genetically more susceptible to reinfections with Octosporea bayeri than naturally uninfected D. magna. We then collected from each of 22 populations both uninfected and infected D. magna genotypes. All were treated against parasites and kept in their asexual phase. We estimated their relative fitness in an experiment against a tester genotype and in another experiment in direct competition. Consistently, we found no difference in competitive abilities between uninfected and cured but formerly infected genotypes. This was the case both in the presence as well as in the absence of sympatric parasites during the competition trials.Our data do not support the inbreeding-infection hypothesis. They also do not support a cost of resistance, however ignoring other parasite strains or parasite species. We suggest as a possible explanation for our results that resistance genes might segregate largely independently of other fitness associated genes in this system

    Androgen receptor expresion in breast cancer: Relationship with clinicopathological characteristics of the tumors, prognosis, and expression of metalloproteases and their inhibitors

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    <p>Abstract</p> <p>Background</p> <p>In the present study we analyze, in patients with breast cancer, the tumor expression of androgen receptors (AR), its relationship with clinicopathological characteristics and with the expression of several matrix metalloproteases (MMPs) and their inhibitors (TIMPs), as well as with prognosis.</p> <p>Methods</p> <p>An immunohistochemical study was performed using tissue microarrays and specific antibodies against AR, MMPs -1, -2, -7, -9, -11, -13, -14, and TIMPs -1, -2 and -3. More than 2,800 determinations on tumor specimens from 111 patients with primary invasive ductal carcinoma of the breast (52 with axillary lymph node metastases and 59 without them) and controls were performed. Staining results were categorized using a score based on the intensity of the staining and a specific software program calculated the percentage of immunostained cells automatically.</p> <p>Results</p> <p>A total of 83 cases (74.8%) showed a positive immunostaining for AR, but with a wide variation in the staining score values. There were no significant associations between the total immunostaining scores for AR and any clinicopathological parameters. However, score values for MMP-1, -7 and -13, were significantly higher in AR-positive tumors than in AR-negative tumors. Likewise, when we considered the cellular type expressing each factor, we found that AR-positive tumors had a higher percentage of cases positive for MMP-1, -7, -11, and TIMP-2 in their malignant cells, as well as for MMP-1 in intratumoral fibroblasts. On the other hand, multivariate analysis demonstrated that patients with AR-positive tumors have a significant longer overall survival than those with AR-negative breast carcinomas (<it>p </it>= 0.03).</p> <p>Conclusion</p> <p>Our results confirm that AR are commonly expressed in breast cancer, and are correlated with the expression of some MMPs and TIMP-2. Although we found a specific value of AR expression to be a prognostic indicator in breast cancer, the functional role of AR in these neoplasms is still unclear and further data are needed in order to clarify their biological signification in breast cancer.</p

    A prognostic DNA methylation signature for stage I non-small-cell lung cancer

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    Purpose Non-small-cell lung cancer (NSCLC) is a tumor in which only small improvements in clinical outcome have been achieved. The issue is critical for stage I patients for whom there are no available biomarkers that indicate which high-risk patients should receive adjuvant chemotherapy. We aimed to find DNA methylation markers that could be helpful in this regard. Patients and Methods A DNA methylation microarray that analyzes 450,000 CpG sites was used to study tumoral DNA obtained from 444 patients with NSCLC that included 237 stage I tumors. The prognostic DNA methylation markers were validated by a single-methylation pyrosequencing assay in an independent cohort of 143 patients with stage I NSCLC. Results Unsupervised clustering of the 10,000 most variable DNA methylation sites in the discovery cohort identified patients with high-risk stage I NSCLC who had shorter relapse-free survival (RFS; hazard ratio [HR], 2.35; 95% CI, 1.29 to 4.28; P = .004). The study in the validation cohort of the significant methylated sites from the discovery cohort found that hypermethylation of five genes was significantly associated with shorter RFS in stage I NSCLC: HIST1H4F, PCDHGB6, NPBWR1, ALX1, and HOXA9. A signature based on the number of hypermethylated events distinguished patients with high-and low-risk stage I NSCLC (HR, 3.24; 95% CI, 1.61 to 6.54; P = .001). Conclusion The DNA methylation signature of NSCLC affects the outcome of stage I patients, and it can be practically determined by user-friendly polymerase chain reaction assays. The analysis of the best DNA methylation biomarkers improved prognostic accuracy beyond standard staging. (C) 2013 by American Society of Clinical Oncology
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