Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
See detailIR and UV spectroscopic signatures of DNA structures in the gas phase
Gabelica, Valérie ULg

Conference (2009, July 08)

Detailed reference viewed: 10 (0 ULg)
See detailIR and UV spectroscopy of DNA ions stored in a quadrupole ion trap mass spectrometer
Gabelica, Valérie ULg; Rosu, Frédéric ULg; Gregoire, Gilles et al

Conference (2008, February 15)

Electrospray mass spectrometry (ESI-MS) can be used to transfer large biomolecular complexes from the solution to the gas phase. However, a longstanding question is whether the gas-phase multiply-charged ... [more ▼]

Electrospray mass spectrometry (ESI-MS) can be used to transfer large biomolecular complexes from the solution to the gas phase. However, a longstanding question is whether the gas-phase multiply-charged ions produced by ESI-MS keep a folded conformation in the absence of solvent. Nucleic acid secondary structures are determined by hydrogen bonding interactions between nucleic bases and by stacking interactions between neighboring base pairs. In solution, infrared (IR) and ultraviolet (UV) spectroscopies provide information on hydrogen bonding and stacking interactions in nucleic acids, respectively. Here we will show how IR and UV spectra of gas-phase ions can be recorded, and what can be learned on the structure of nucleic acids (double helices and quadruple helices) in the gas phase. The IR spectroscopy experiments on DNA negative ions were carried out at the CLIO free electron laser (FEL) center using an electrospray quadrupole ion trap mass spectrometer (Esquire 3000, Bruker Daltonics, Germany) modified to inject the IR beam in the trap through the ring electrode. IRMPD spectra are recorded by monitoring the relative fragmentation efficiency of mass-selected parent ions as a function of the excitation wavenumber, in the range 1000-2000 cm-1. Data interpretation on these large biomolecule ions is made using carefully chosen control experiments. The major finding is a fingerprint of hydrogen bonding in the gas phase in the guanine C6=O6 stretching mode, that allows probing the conservation of G-quartets in the gas phase. The experiments demonstrate the conservation of G-quadruplex hydrogen bonds in the human telomeric sequence d(TTAGGG)4. The UV spectroscopy experiments were carried out using a tunable OPO laser (Continuum Lasers, Santa Clara, CA, USA) with frequency doubling. The laser is interfaced with a Finnigan LCQ ESI-QIT mass spectrometer. The UV action spectra were recorded by monitoring electron detachment from DNA multiply charged anions as a function of the wavelength between 220 and 300 nm. Preliminary results suggest that stacking interactions are preserved in duplexes containing GC base pairs, and in G-quadruplexes containing inner cations. [less ▲]

Detailed reference viewed: 36 (1 ULg)
See detailIR and UV Spectroscopy of DNA Ions Stored in Trap Instruments
Gabelica, Valérie ULg

Conference (2008, October 11)

Detailed reference viewed: 16 (0 ULg)
See detailIR photometry of ESO calibration stars (van der Bliek+ 1996)
van der Bliek, N. S.; Manfroid, Jean ULg; Bouchet, P.

Report (1996)

We describe the infrared (IR) photometric system for the single channel photometers at ESO, which have been used from 1983 until 1994. In addition to the broadband near infrared (NIR, 1-5μm) photometric ... [more ▼]

We describe the infrared (IR) photometric system for the single channel photometers at ESO, which have been used from 1983 until 1994. In addition to the broadband near infrared (NIR, 1-5μm) photometric system presented in 1991 by Bouchet et al. and Bersanelli et al., we describe a narrow-band NIR photometric system and a mid infrared (MIR, 7-20μm) photometric system. We also extend the set of NIR standard stars by Bouchet et al. towards fainter objects (K=~9). The photometric data of the standard stars in these systems were extracted from the complete IR photometric data archive of ESO, covering 10 years. The zeropoints of the NIR photometry are set by assuming that HR 3314 has a V-magnitude of 3.89, and that V-K=-0.05, J-K=-0.01, H-K=-0.01, K-L'=0.00, K-M=0.00. The zeropoints of the MIR photometry are set by assuming that the colours ofβ Hyi (HR 0098) and α CenA (HR 5459) are equal to the colours of the Sun. We adopt the absolute calibration of Megessier (1995A&A...296..771M) for the NIR and we argue that this calibration can be extrapolated to 20μm, using the MIR calibrations by Rieke et al. (1985AJ.....90..900R) and Cohen et al. (1992AJ....104.1650C). The definition of the zeropoints is consistent with the absolute calibration. We obtained accurate (Ï =~0.02mag.) NIR photometry of about 240 standard stars and MIR photometry of about 40 standard stars (Ï =~0.04mag). Comparison of our NIR photometric system with other well established systems shows that there are some small colour dependencies and zeropoint offsets which are always smaller than about 0.02mag. except for the L' band. (3 data files). [less ▲]

Detailed reference viewed: 12 (2 ULg)
See detailIR spectroscopy of DNA structures
Gabelica, Valérie ULg

Conference (2009, June 11)

Detailed reference viewed: 11 (0 ULg)
Full Text
Peer Reviewed
See detailIr-LBP, an ixodes ricinus tick salivary LTB4-binding lipocalin, interferes with host neutrophil function.
Beaufays, Jérôme ULg; Adam, Benoit; Menten-Dedoyart, Catherine ULg et al

in PLoS ONE (2008), 3(12), 3987

BACKGROUND: During their blood meal, ticks secrete a wide variety of proteins that can interfere with their host's defense mechanisms. Among these proteins, lipocalins play a major role in the modulation ... [more ▼]

BACKGROUND: During their blood meal, ticks secrete a wide variety of proteins that can interfere with their host's defense mechanisms. Among these proteins, lipocalins play a major role in the modulation of the inflammatory response. METHODOLOGY/PRINCIPAL FINDINGS: We previously identified 14 new lipocalin genes in the tick Ixodes ricinus. One of them codes for a protein that specifically binds leukotriene B4 with a very high affinity (Kd: +/-1 nM), similar to that of the neutrophil transmembrane receptor BLT1. By in silico approaches, we modeled the 3D structure of the protein and the binding of LTB4 into the ligand pocket. This protein, called Ir-LBP, inhibits neutrophil chemotaxis in vitro and delays LTB4-induced apoptosis. Ir-LBP also inhibits the host inflammatory response in vivo by decreasing the number and activation of neutrophils located at the tick bite site. Thus, Ir-LBP participates in the tick's ability to interfere with proper neutrophil function in inflammation. CONCLUSIONS/SIGNIFICANCE: These elements suggest that Ir-LBP is a "scavenger" of LTB4, which, in combination with other factors, such as histamine-binding proteins or proteins inhibiting the classical or alternative complement pathways, permits the tick to properly manage its blood meal. Moreover, with regard to its properties, Ir-LBP could possibly be used as a therapeutic tool for illnesses associated with an increased LTB4 production. [less ▲]

Detailed reference viewed: 83 (22 ULg)
Full Text
Peer Reviewed
See detailIR-visible sum-frequency vibrational spectroscopy of Biphenyl-3 methylene thiol monolayer on gold and silver: effect of the visible wavelength on the SFG spectrum
Humbert, Christophe; Dreesen, Laurent ULg; Mani, A. A. et al

in Surface Science (2002), 502-503

We measured IR-visible sum-frequency generation spectra of CH3-(C6H4)2-(CH2)3-S-H (Biphenyl-3) self-assembled monolayers on a silver and a gold substrate. For the latter substrate, we observed different ... [more ▼]

We measured IR-visible sum-frequency generation spectra of CH3-(C6H4)2-(CH2)3-S-H (Biphenyl-3) self-assembled monolayers on a silver and a gold substrate. For the latter substrate, we observed different interference patterns between the resonant signal of the CH vibration and the non-resonant contribution of the substrate as a function of the visible beam wavelength. The non-linear response of the gold substrate is enhanced around 480 nm corresponding to the s-d interband transition. Such effect is not observed for the silver substrate the interband transition of which is located out of the investigated visible spectral range of 450-700 nm. [less ▲]

Detailed reference viewed: 35 (0 ULg)
Full Text
See detailIRC +10216: a peanut nebula!
Le Bertre, Thibault; Magain, Pierre ULg; Remy, Marc

in The Messenger (1989), 55

Not Available

Detailed reference viewed: 11 (1 ULg)
Peer Reviewed
See detailIRF-3 dependent activation of inflammatory dendritic cells by extracellular host DNA mediates the adjuvant activity of alum on Th2 responses
Marichal, Thomas ULg; Ohata, Keichii; Bedoret, Denis et al

in Proceedings of the 25th annual meeting of the European Macrophage and Dendritic Cell Society (2011)

Detailed reference viewed: 11 (3 ULg)
See detailIRF3 is essential for house dust mite-induced airway allergy in mice
Marichal, Thomas ULg; Bedoret, Denis; Mesnil, Claire ULg et al

in Proceedings GIGA-Day 2011 (2011, May)

Detailed reference viewed: 20 (9 ULg)
Peer Reviewed
See detailIRF3 is required for induction of allergic airway inflammation by dendritic cells
Marichal, Thomas ULg; Bedoret, Denis; Goriely, M. et al

Conference (2009)

Detailed reference viewed: 46 (11 ULg)
Peer Reviewed
See detailIRF3 is required for induction of allergic airway inflammation by dendritic cells
Marichal, Thomas ULg; Bedoret, Denis; Goriely, S et al

Poster (2009)

Detailed reference viewed: 10 (0 ULg)
Full Text
Peer Reviewed
See detailIRF3 is required for the induction of allergic airway inflammation by lung dendritic cells in a mouse model of house dust mite-induced atopic asthma
Marichal, Thomas ULg; Bedoret, Denis; Goriely, M. et al

in Abstracts of the 17th Annual European Respiratory Society Congress, Vienna, Austria (2009)

Detailed reference viewed: 43 (14 ULg)
Full Text
Peer Reviewed
See detailIRF6 Screening of Syndromic and a priori Non-Syndromic Cleft Lip and Palate Patients: Identification of a New Type of Minor VWS Sign.
Desmyter, L.; Ghassibe, M.; Revencu, N. et al

in Molecular Syndromology (2010), 1(2), 67-74

Van der Woude syndrome (VWS), caused by dominant IRF6 mutation, is the most common cleft syndrome. In 15% of the patients, lip pits are absent and the phenotype mimics isolated clefts. Therefore, we ... [more ▼]

Van der Woude syndrome (VWS), caused by dominant IRF6 mutation, is the most common cleft syndrome. In 15% of the patients, lip pits are absent and the phenotype mimics isolated clefts. Therefore, we hypothesized that some of the families classified as having non-syndromic inherited cleft lip and palate could have an IRF6 mutation. We screened in total 170 patients with cleft lip with or without cleft palate (CL/P): 75 were syndromic and 95 were a priori part of multiplex non-syndromic families. A mutation was identified in 62.7 and 3.3% of the patients, respectively. In one of the 95 a priori non-syndromic families with an autosomal dominant inheritance (family B), new insights into the family history revealed the presence, at birth, of lower lip pits in two members and the diagnosis was revised as VWS. A novel lower lip sign was observed in one individual in this family. Interestingly, a similar lower lip sign was also observed in one individual from a 2nd family (family A). This consists of 2 nodules below the lower lip on the external side. In a 3rd multiplex family (family C), a de novo mutation was identified in an a priori non-syndromic CL/P patient. Re-examination after mutation screening revealed the presence of a tiny pit-looking lesion on the inner side of the lower lip leading to a revised diagnosis of VWS. On the basis of this data, we conclude that IRF6 should be screened when any doubt rises about the normality of the lower lip and also if a non-syndromic cleft lip patient (with or without cleft palate) has a family history suggestive of autosomal dominant inheritance. [less ▲]

Detailed reference viewed: 15 (1 ULg)
Full Text
See detailIRGA GAS SAMPLING SYSTEM DIMENSIONING: LABORATORY AND FIELD EXPERIMENTS
De Ligne, Anne ULg; Joly, Lilian; Cousin, Julien et al

Poster (2014, September 23)

The gas sampling system (GSS), which carries air from the sampling point to the IRGA, is an essential component of the eddy covariance system. It has to meet several constraints, among which minimizing ... [more ▼]

The gas sampling system (GSS), which carries air from the sampling point to the IRGA, is an essential component of the eddy covariance system. It has to meet several constraints, among which minimizing high frequency attenuation of concentration measurement and keeping pressure drop in the measurement cell in an acceptable range. Rain cup, filters, tubes and pumps are key elements of this system and need proper dimensioning. The elaboration of the ICOS protocol for IRGA required such dimensioning and optimization. Laboratory and field measurements were carried out with this aim. In the laboratory, a dynamic calibration bench was developed to investigate experimentally the pressure drop and the concentration fluctuation attenuation caused by different filters. In the field, three LI-7200 equipped with different GSS were installed and run at the Dorinne Terrestrial Observatory (ICOS-Belgium). Main experiment conclusions were that: • The shape and size of the rain cup has a critical impact on cut off frequencies • The filter porosity and size has a critical impact on pressure drop • Filter heating is necessary in order to avoid condensation and filter blocking These experiments led to the definition of the GSS functioning range that is finally proposed in the ICOS IRGA protocol. [less ▲]

Detailed reference viewed: 5 (0 ULg)