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
Full Text
Peer Reviewed
See detailHigh-throughput method for comparative analysis of denaturing gradient gel electrophoresis profiles from human fecal samples reveals significant increases in two bifidobacterial species after inulin-type prebiotic intake.
Joossens, Marie; Huys, Geert; Van Steen, Kristel ULg et al

in FEMS Microbiology Ecology (2011), 75(2), 343-9

Denaturing gradient gel electrophoresis (DGGE) is one of the most commonly used molecular tools to study complex microbial communities. Despite its widespread use, meaningful interpretative analysis ... [more ▼]

Denaturing gradient gel electrophoresis (DGGE) is one of the most commonly used molecular tools to study complex microbial communities. Despite its widespread use, meaningful interpretative analysis remains a major drawback of this method. We evaluated the combination of computer-assisted band-matching with nonparametric statistics for comparative analysis of DGGE banding patterns. Fecal samples from 17 healthy volunteers who consumed 20 g of the prebiotic compound oligofructose-enriched inulin (OF-IN) for 4 weeks were analyzed before and after treatment. DGGE fingerprinting profiles were analyzed using bionumerics software version 4.6., which resulted in a data matrix that was used for statistical analysis. When comparing DGGE profiles before and after OF-IN intake with a Wilcoxon nonparametric test for paired data, two band-classes increased significantly after OF-IN intake (P<0.003 and <0.02). These two band-classes could be assigned to the species Bifidobacterium longum and Bifidobacterium adolescentis by band-sequencing analysis, and their significant increase was quantitatively confirmed with real-time PCR using species-specific primers (respectively P<0.012 and <0.010). Therefore, the nonparametric analysis of a data matrix obtained by computer-assisted band-matching of complex profiles facilitated the interpretative analysis of these profiles and provided an objective and high-throughput method for the detection of significant taxonomic differences in larger numbers of complex profiles. [less ▲]

Detailed reference viewed: 213 (10 ULg)
Full Text
See detailHigh-throughput methodology applied to screening of carbohydrate-based surfactant interfacial properties for colloidal system formulations
Razafindralambo, Hary ULg; Blecker, Christophe ULg; Deroanne et al

Poster (2009)

Carbohydrate-based surfactants (CBS) constitute an attractive class of amphiphilic molecules owing to their structural diversity generating a wide range of properties which could be developed in food and ... [more ▼]

Carbohydrate-based surfactants (CBS) constitute an attractive class of amphiphilic molecules owing to their structural diversity generating a wide range of properties which could be developed in food and non-food applications. Based on many functional groups of the carbohydrate part, it is possible to design multiple amphiphilic structures of CBS varying in the hydrophilic head groups (mono-, oligo-, or polysaccharides), hydrophobic tail (mono-, di-, tricatenar) but also in the linker/spacer between them. The main structures of CBS include mono- and bicatenar glycolipids, bolaforms, and gemini. Moreover, CBS compounds can be produced from the most abundant renewable materials allowing large product concept possibilities. Among general properties of surfactants, interfacial properties molecules occupy a fundamental key role for colloidal system formulations since they control most of technological aptitudes required for forming and stabilizing food, cosmetic, agrochemical, detergent, and pharmaceutical products. High-throughput methodology applied to screening of CBS interfacial properties appears crucial for achieving optimum formulations of colloidal systems like foams and emulsions for which small amounts of single or mix surface-active agents are often needed and numerous physical and chemical parameters are involved. This general approach may be applied to any amphiphilic molecules produced from other renewable resources of surface-active compounds like micro-organisms and by direct extraction from vegetable materials. One of the key factors for the development of this methodology is the use of automated instrument systems in laboratory scale which are still lacking in this field compared to those existing in the analytical chemistry and biochemistry areas. [less ▲]

Detailed reference viewed: 42 (10 ULg)
Full Text
Peer Reviewed
See detailHigh-throughput quantification of the mechanical competence of murine femora - A highly automated approach for large-scale genetic studies
Ruffoni, Davide ULg; Kohler, T.; Voide, R. et al

in BONE (2013), 55(1), 216-221

Animal models are widely used to gain insight into the role of genetics on bone structure and function. One of the main strategies to map the genes regulating specific traits is called quantitative trait ... [more ▼]

Animal models are widely used to gain insight into the role of genetics on bone structure and function. One of the main strategies to map the genes regulating specific traits is called quantitative trait loci (QTL) analysis, which generally requires a very large number of animals (often more than 1000) to reach statistical significance. QTL analysis for mechanical traits has been mainly based on experimental mechanical testing, which, in view of the large number of animals, is time consuming. Hence, the goal of the present work was to introduce an automated method for large-scale high-throughput quantification of the mechanical properties of murine femora. Specifically, our aims were, first, to develop and validate an automated method to quantify murine femoral bone stiffness. Second, to test its high-throughput capabilities on murine femora from a large genetic study, more specifically, femora from two growth hormone (GH) deficient inbred strains of mice (B6-lit/lit and C3.B6-lit/lit) and their first (F1) and second (F2) filial offsprings. Automated routines were developed to convert micro-computed tomography (micro-CT) images of femora into micro-finite element (micro-FE) models. The method was experimentally validated on femora from C57BL/6J and C3H/HeJ mice: for both inbred strains the micro-FE models closely matched the experimentally measured bone stiffness when using a single tissue modulus of 13.06 GPa. The mechanical analysis of the entire dataset (n = 1990) took approximately 44 CPU hours on a supercomputer. In conclusion, our approach, in combination with QTL analysis could help to locate genes directly involved in controlling bone mechanical competence. (C) 2013 Elsevier Inc. All rights reserved. [less ▲]

Detailed reference viewed: 22 (2 ULg)
Full Text
Peer Reviewed
See detailHigh-throughput sequencing analysis reveals the genetic diversity of different regions of the murine norovirus genome during in vitro replication
Mauroy, Axel ULg; Taminiau, Bernard ULg; Nezer, Carine et al

in Archives of Virology (2017), 16(4), 1019-1023

In this study, we report the genetic diversity and nucleotide mutation rates of five representative regions of the murine norovirus genome during in vitro passages. The mutation rates were similar in ... [more ▼]

In this study, we report the genetic diversity and nucleotide mutation rates of five representative regions of the murine norovirus genome during in vitro passages. The mutation rates were similar in genomic regions encompassing partial coding sequences for non-structural (NS) 1-2, NS5, NS6, NS7 proteins within open reading frame (ORF) 1. In a region encoding a portion of the major capsid protein (VP1) within ORF2 (also including the ORF4 region) and a portion of the minor structural protein (VP2), the mutation rates were estimated to be at least one order of magnitude higher. The VP2 coding region was found to have the highest mutation rate. [less ▲]

Detailed reference viewed: 32 (9 ULg)
Full Text
Peer Reviewed
See detailHigh-throughput sequencing of toxins with pharmacological interest: proof of concept and first applications
Echterbille, Julien ULg; Degueldre, Michel ULg; Boulanger, Madeleine ULg et al

Conference (2015, September 28)

Animal venoms are complex chemical cocktails, comprising wide ranges of biologically active reticulated peptides that target with high selectivity and efficacy varieties of membrane receptors. Assuming ... [more ▼]

Animal venoms are complex chemical cocktails, comprising wide ranges of biologically active reticulated peptides that target with high selectivity and efficacy varieties of membrane receptors. Assuming the fact that each of the 170,000 venomous species reported can produce more than 250 bioactive toxins, at least 40,000,000 bioactive peptides and proteins may be discovered. Among the four described species of mambas, Eastern Jameson’s mamba (Dendroaspis jamesonii kaimosae) venom is the less characterized since only 9 peptides are referenced in database. This work aims at developing a new strategy devoted to the deep analysis of animal venoms. Our approach consists in a first separation of the venom using cation exchange chromatography. Each primary fraction is then purified a second time by classical RP-HPLC. A total of 328 fractions, containing amongst 1 and 4 toxins, are finally collected. MALDI-MS analysis of each fraction is done in order (1) to obtain information about masses and (2) to obtain sequences of toxins thanks to MALDI-In Source Decay (ISD) dissociation coupled with on MALDI target plate reduction of the peptides. ISD has already been demonstrated efficient for toxin sequencing1, and especially when using 1,5-DAN as reducing matrix2. ISD yields to sequences that cover more than 50% of peptide sequences by series of singly charged c-type ions. Thanks to this methodology, we were able to obtain 85% of satisfactory results i.e. spectra giving quite long tags of amino acids (up to 20 residues). As a way to validate our method, a tag coming from ISD spectrum interpretation has found a match in database for an Eastern Jameson’s mamba toxin. The global sequence has then been obtained by extrapolation on the ISD spectrum. Since ISD spectra are simpler than classical MS/MS spectra, automation of spectra interpretation, difficult with other fragmentation techniques (CID, ETD…), is implementable. In the near future, sequences obtained with this approach will be used to direct tests of biological activity through sequence homologies with already known ligands for different kinds of membrane receptors. [less ▲]

Detailed reference viewed: 38 (13 ULg)
Full Text
Peer Reviewed
See detailHigh-throughput strategies for the discovery and engineering of enzymes for biocatalysis
Jacques, Philippe ULg; Béchet, M.; Bigan, M. et al

in Bioprocess and Biosystems Engineering (2017), 40(2),

Detailed reference viewed: 17 (3 ULg)
Full Text
See detailHigh-throughput synthesis of functional oxide films
Dhanapal, Pravarthana ULg

Doctoral thesis (2014)

Epitaxy of metal oxides is of great interest since it provides a way to obtain desired novel properties for the applications such as electronics and energy. However, earlier epitaxy research's have been ... [more ▼]

Epitaxy of metal oxides is of great interest since it provides a way to obtain desired novel properties for the applications such as electronics and energy. However, earlier epitaxy research's have been restricted because of the limited range of compositions and low-index of commercially available single crystal substrates. Consequently, novel epitaxy synthesis methods need to be developed in order to go beyond the present demands of of single crystal substrates in terms of phase, composition, size, orientation and symmetry. In this research work, we have developed a high-throughput synthesis process, called combinatorial substrate epitaxy (CSE), where an oxide film is grown epitaxially on a polycrystalline substrate. As a proof-of-concept, we firstly fabricated Ca3Co4O9 films on Al2O3 ceramics. Films have a good local epitaxial registry, and the Seebeck coefficient is about 170 µV/K at 300 K. High quality BiFeO3/La0.7Sr0.3MnO3 thin film heterostructures were secondly deposited on dense LaAlO3 ceramics prepared by spark plasma sintering. Piezoforce microscopy was used to confirm the local ferroelectric properties. Thirdly, we investigate the growth of of metastable monoclinic Dy2Ti2O7 epitaxial films on polycrystalline La2Ti2O7 substrates. We conclude that CSE approach opens the way towards unexpected electronic properties in oxide films. [less ▲]

Detailed reference viewed: 166 (14 ULg)
Full Text
Peer Reviewed
See detailHigh-throughput synthesis of thermoelectric Ca3Co 4O9 films
Dhanapal, Pravarthana ULg; Lebedev, O. I.; Hebert, S. et al

in Applied Physics Letters (2013), 103

Properties of complex oxide thin films can be tuned over a range of values as a function of mismatch, composition, orientation, and structure. Here, we report a strategy for growing structured epitaxial ... [more ▼]

Properties of complex oxide thin films can be tuned over a range of values as a function of mismatch, composition, orientation, and structure. Here, we report a strategy for growing structured epitaxial thermoelectric thin films leading to improved Seebeck coefficient. Instead of using single-crystal sapphire substrates to support epitaxial growth, Ca3Co 4O9 films are deposited, using the Pulsed Laser Deposition technique, onto Al2O3 polycrystalline substrates textured by spark plasma sintering. The structural quality of the 2000 Å thin film was investigated by transmission electron microscopy, while the crystallographic orientation of the grains and the epitaxial relationships were determined by electron backscatter diffraction. The use of a polycrystalline ceramic template leads to structured films that are in good local epitaxial registry. The Seebeck coefficient is about 170 μV/K at 300 K, a typical value of misfit material with low carrier density. This high-throughput process, called combinatorial substrate epitaxy, appears to facilitate the rational tuning of functional oxide films, opening a route to the epitaxial synthesis of high quality complex oxides. © 2013 AIP Publishing LLC. [less ▲]

Detailed reference viewed: 76 (1 ULg)
Full Text
Peer Reviewed
See detailHigh-urgency kidney transplantation in the Eurotransplant Kidney Allocation System: success or waste of organs? The Eurotransplant 15-year all-centre survey.
Assfalg, Volker; Huser, Norbert; van Meel, Marieke et al

in Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association (2016)

BACKGROUND: In the Eurotransplant Kidney Allocation System (ETKAS), transplant candidates can be considered for high-urgency (HU) status in case of life-threatening inability to undergo renal replacement ... [more ▼]

BACKGROUND: In the Eurotransplant Kidney Allocation System (ETKAS), transplant candidates can be considered for high-urgency (HU) status in case of life-threatening inability to undergo renal replacement therapy. Data on the outcomes of HU transplantation are sparse and the benefit is controversial. METHODS: We systematically analysed data from 898 ET HU kidney transplant recipients from 61 transplant centres between 1996 and 2010 and investigated the 5-year patient and graft outcomes and differences between relevant subgroups. RESULTS: Kidney recipients with an HU status were younger (median 43 versus 55 years) and spent less time on the waiting list compared with non-HU recipients (34 versus 54 months). They received grafts with significantly more mismatches (mean 3.79 versus 2.42; P < 0.001) and the percentage of retransplantations was remarkably higher (37.5 versus 16.7%). Patient survival (P = 0.0053) and death with a functioning graft (DwFG; P < 0.0001) after HU transplantation were significantly worse than in non-HU recipients, whereas graft outcome was comparable (P = 0.094). Analysis according to the different HU indications revealed that recipients listed HU because of an imminent lack of access for dialysis had a significantly worse patient survival (P = 0.0053) and DwFG (P = 0.0462) compared with recipients with psychological problems and suicidality because of dialysis. In addition, retransplantation had a negative impact on patient and graft outcome. CONCLUSIONS: Facing organ shortages, increasing wait times and considerable mortality on dialysis, we question the current policy of HU allocation and propose more restrictive criteria with regard to individuals with vascular complications or repeated retransplantations in order to support patients on the non-HU waiting list with a much better long-term prognosis. [less ▲]

Detailed reference viewed: 37 (3 ULg)
Full Text
Peer Reviewed
See detailHigh-volume versus standard-volume haemofiltration for septic shock patients with acute kidney injury (IVOIRE study): a multicentre randomized controlled trial
JOANNES-BOYAU, Olivier; HONORE, Patrick; PEREZ, Paul et al

in Intensive Care Medicine (2013), 39(9), 1535-1546

PURPOSE : Septic shock is a leading cause of death among critically ill patients, in particular when complicated by acute kidney injury (AKI). Small experimental and human clinical studies have suggested ... [more ▼]

PURPOSE : Septic shock is a leading cause of death among critically ill patients, in particular when complicated by acute kidney injury (AKI). Small experimental and human clinical studies have suggested that high-volume haemofiltration (HVHF) may improve haemodynamic profile and mortality. We sought to determine the impact of HVHF on 28-day mortality in critically ill patients with septic shock and AKI. METHODS: This was a prospective, randomized, open, multicentre clinical trial conducted at 18 intensive care units in France, Belgium and the Netherlands. A total of 140 critically ill patients with septic shock and AKI for less than 24 h were enrolled from October 2005 through March 2010. Patients were randomized to either HVHF at 70 mL/kg/h or standard-volume haemofiltration (SVHF) at 35 mL/kg/h, for a 96-h period. RESULTS: Primary endpoint was 28-day mortality. The trial was stopped prematurely after enrolment of 140 patients because of slow patient accrual and resources no longer being available. A total of 137 patients were analysed (two withdrew consent, one was excluded); 66 patients in the HVHF group and 71 in the SVHF group. Mortality at 28 days was lower than expected but not different between groups (HVHF 37.9 % vs. SVHF 40.8 %, log-rank test p = 0.94). There were no statistically significant differences in any of the secondary endpoints between treatment groups. CONCLUSIONS: In the IVOIRE trial, there was no evidence that HVHF at 70 mL/kg/h, when compared with contemporary SVHF at 35 mL/kg/h, leads to a reduction of 28-day mortality or contributes to early improvements in haemodynamic profile or organ function. HVHF, as applied in this trial, cannot be recommended for treatment of septic shock complicated by AKI. [less ▲]

Detailed reference viewed: 60 (0 ULg)
Full Text
Peer Reviewed
See detailHigh-yield radiosynthesis and preliminary in vivo evaluation of p-[18F]MPPF, a fluoro analog of WAY-100635.
Le Bars, Didier; Lemaire, Christian ULg; Ginovart, N. et al

in Nuclear Medicine & Biology (1998), 25(4), 343-50

No-carrier-added 4-[18F]fluoro-N-[2-[1-(2-methoxyphenyl)-1 piperazinyl]ethyl-N-2-pyridinyl-benzamide (p-[18F]MPPF) was synthesized by nucleophilic substitution of the corresponding nitro compound in the ... [more ▼]

No-carrier-added 4-[18F]fluoro-N-[2-[1-(2-methoxyphenyl)-1 piperazinyl]ethyl-N-2-pyridinyl-benzamide (p-[18F]MPPF) was synthesized by nucleophilic substitution of the corresponding nitro compound in the presence of Kryptofix 222 and K2CO3 by microwave heating (3 min, 500 W) using a remotely controlled radiosynthesis. Baseline separation of p-[18F]MPPF from the nitro derivative was performed on a semipreparative HPLC C18 column. After Sep-Pak formulation, the radiopharmaceutical was obtained with a radiochemical yield of 25% (EOS) in about 70 min. Specific radioactivity averaged between 1-5 Ci/micromol EOS. Labelling of the ortho and meta derivatives was also attempted. Brain uptake of p-[18F]MPPF was studied with PET on fluothane-anesthetized cats. Following intravenous injection of p-[18F]MPPF, high accumulation of radioactivity was observed in the hippocampus and cerebral cortex. Low levels of radioactivity were observed in cerebellum. At 30 min, the mean hippocampus/cerebellum and cortex/cerebellum ratios were 5 and 3.8, respectively. The accumulation of the tracer was blocked by prior administration of reference WAY-100635, demonstrating the specificity of the ligand. [less ▲]

Detailed reference viewed: 47 (8 ULg)
Peer Reviewed
See detailHigh-Yield Synthesis of a (3H)Ethylenediamine Ditetrodotoxin Derivative
Bontemps, José; Cantineau, Robert; Grandfils, Christian ULg et al

in Analytical Biochemistry (1984), 139

Detailed reference viewed: 14 (3 ULg)
Full Text
Peer Reviewed
See detailHigh-Yield Synthesis Of The Bovine Leukemia-Virus (Blv) P24 Major Internal Protein In Saccharomyces-Cerevisiae
Dumont, Jacques; Legrain, M.; Portetelle, Daniel ULg et al

in Gene (1989), 79(2),

Bovine leukemia virus (BLV) p24 gene was expressed in Saccharomyces cerevisiae under the control of the PHO5 (encoding repressible acid phosphatase, rAPase) promoter. Yeast cells were transformed by a ... [more ▼]

Bovine leukemia virus (BLV) p24 gene was expressed in Saccharomyces cerevisiae under the control of the PHO5 (encoding repressible acid phosphatase, rAPase) promoter. Yeast cells were transformed by a yeast-E. coli shuttle vector carrying the PHO5 promoter, the p24 gene and the CYC1 transcription terminator. After low inorganic phosphate (Pi) induction of the PHO5 promoter, p24 accumulated in the producing cells up to a concentration representing 10% of total soluble proteins. The expression level of p24 gene was not increased by insertion of the positive regulatory gene PHO4 on the p24 expression vector. The p24 produced in this system and incubated in crude yeast extract showed a remarkably high resistance to proteolytic degradation, a feature that presumably correlates with the compact globular conformation of the protein combined to the stabilizing effect of the N-terminal residue. [less ▲]

Detailed reference viewed: 10 (0 ULg)
Full Text
Peer Reviewed
See detailHigher frontal EEG synchronization in young women with major depression: a marker for increased homeostatic sleep pressure?
Birchler-Pedross, Angelina; Frey, Sylvia; Chellappa, Sarah Laxhmi ULg et al

in Sleep (2011), 34(12), 1699-706

STUDY OBJECTIVES: Major depressive disorder (MDD) is often associated with disturbances in circadian and/or sleep-wake dependent processes, which both regulate daytime energy and sleepiness levels. DESIGN ... [more ▼]

STUDY OBJECTIVES: Major depressive disorder (MDD) is often associated with disturbances in circadian and/or sleep-wake dependent processes, which both regulate daytime energy and sleepiness levels. DESIGN: Analysis of continuous electroencephalographic (EEG) recordings during 40 h of extended wakefulness under constant routine conditions. Artifact-free EEG samples derived from 12 locations were subjected to spectral analysis. Additionally, half-hourly ratings of subjective tension and sleepiness levels and salivary melatonin measurements were collected. SETTING: Centre for Chronobiology, Psychiatric Hospitals of the University of Basel, Switzerland. PARTICIPANTS: Eight young healthy women and 8 young untreated women with MDD. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: MDD women exhibited higher frontal low-frequency (FLA) EEG activity (0.5-5.0 Hz) during extended wakefulness than controls, particularly during the night. Enhanced FLA was paralleled by higher levels of subjective sleepiness and tension. In MDD women, overall FLA levels correlated positively with depression scores. The timing of melatonin onset did not significantly differ between the two groups, but the nocturnal secretion of salivary melatonin was significantly attenuated in MDD women. CONCLUSIONS: Our data imply that young women with MDD live on a higher homeostatic sleep pressure level, as indexed by enhanced FLA during wakefulness. Its positive correlation with depression scores indicates a possible functional relationship. High FLA could reflect a use-dependent phenomenon in depression (enhanced cognitive rumination or tension) and/or an attenuated circadian arousal signal. [less ▲]

Detailed reference viewed: 25 (0 ULg)
Full Text
Peer Reviewed
See detailHigher long-lasting ethanol sensitization after adolescent ethanol exposure in mice
Quoilin, Caroline; Didone, Vincent ULg; Tirelli, Ezio ULg et al

in Psychopharmacology (2014), 231

Rationale. Due to their maturing brain, adolescents are suggested to be more vulnerable to the long-term consequences of chronic alcohol use. Increased sensitization to the stimulant effects of ethanol is ... [more ▼]

Rationale. Due to their maturing brain, adolescents are suggested to be more vulnerable to the long-term consequences of chronic alcohol use. Increased sensitization to the stimulant effects of ethanol is a possible consequence of ethanol exposure during adolescence. Objectives. The aim of this study was to characterize the long-term alterations in the stimulant effects of ethanol and in the rate of ethanol sensitization in mice pre-exposed to ethanol during adolescence in comparison to mice pre-exposed to ethanol in adulthood. Methods. Adolescent and adult female SWISS mice were injected with saline or ethanol (2.5 or 4 g/kg) during 14 consecutive days. After a three weeks period of ethanol abstinence, mice were tested as adults before and after a second exposure to daily repeated ethanol injections. Results. All mice pre-exposed to ethanol as adults or adolescents showed higher stimulant effects when re-exposed to ethanol three weeks later. However, this enhanced sensitivity to the stimulant effects of ethanol was of significantly higher magnitude in mice repeatedly injected with high ethanol doses (4g/kg) during adolescence. Furthermore, the increased expression of ethanol stimulant effects in these mice was maintained even after a second procedure of ethanol sensitization. Conclusions. Adolescence is a critical period for the development of a sensitization to ethanol stimulant properties providing that high intermittent ethanol doses are administered. These results might contribute to explain the relationship between age at first alcohol use and risks of later alcohol problems and highlight the dangers of repeated consumption of high alcohol amounts in young adolescents. [less ▲]

Detailed reference viewed: 63 (24 ULg)
Full Text
See detailHigher male than female recombination rate in cattle is controlled by genetic variants effective in both sexes
Kadri, Naveen Kumar ULg; Harland, Chad ULg; Coppieters, Wouter ULg et al

Poster (2015, May 05)

We herein study genetic recombination in three dairy cattle populations from France, New-Zealand and the Netherlands. We apply a new phasing algorithm extracting familial information suited for large half ... [more ▼]

We herein study genetic recombination in three dairy cattle populations from France, New-Zealand and the Netherlands. We apply a new phasing algorithm extracting familial information suited for large half-sib families to reconstruct haplotypes and detect cross-overs (CO). The software is robust to genotyping and map errors. We identify more than 2,000,000 CO events in sperm cells transmitted by 3008 sires to 94,603 offspring, and more than 500,000 CO events in oocytes transmitted by 11,497 cows to 25,390 offspring. When measured in identical family structures, the average number of CO in males (24.0) was found to be larger than in females (21.8). In males, recombination rates were higher closer to telomeres whereas in females, recombination rates dropped at both centromeres and telomeres (probably as a result of lower informativity). The heritability of the global recombination rate (GRR) was close to 0.20 in males and to 0.08 in females. Genetic correlation ranged from 0.38 to 0.69 depending on the population, indicating that shared variants are influencing GRR in both genders. Haplotype-based genome-wide association studies revealed four genome-wide significant QTL, including two previously identified ones (involving REC8 and RNF212). For all QTLs, there was a positive correlation between haplotype effects across sexes, ranging from 0.35 to 0.68. We selected two reference panels of respectively 122 and 215 bulls sequenced at cover > 15x to impute variants in the New-Zealand and French populations. All variants identified by next-generating sequencing in 5 Mb windows encompassing the QTL peaks were imputed with Beagle in order to perform a sequence-based association study. For three QTLs, we identified missense mutations in genes known to be involved in meiosis among the most significantly associated variants. These variants were perfectly associated with the haplotypes underlying the QTL effects. The variant identified in RNF212 had already been reported, whereas missense mutations in MLH3 (N408S) and HFM1 (S1189L) are new findings. Surprisingly, variants previously identified in REC8 did not capture the QTL effect whereas variants in RNF212B, PPP1R3E, BCL2L2, HOMEZ and PABPN1 had much stronger association with the phenotype. The three missense mutations were significant in both genders with two of them accounting for approximately 10% of the genetic variance in males (the allelic substitution effect being approximately equal to one additional CO per genome). Our results are very different from reports of recombination in other species. For instance, in human, recombination rate is higher in females, distinct variants affect recombination rate in males and females and the genetic correlation is close to 0 whereas in cattle, we observed a higher recombination rate in males controlled by shared variants effective in both sexes. [less ▲]

Detailed reference viewed: 116 (12 ULg)
See detailHIGHER MALE THAN FEMALE RECOMBINATION RATE LARGELY CONTROLLED BY MISSENSE VARIANTS IN RNF212, MLH3, HFM1, MSH5 AND MSH4 IN CATTLE
Kadri, Naveen Kumar ULg; Harland, Chad ULg; Faux, Pierre ULg et al

Poster (2016, May 11)

We herein study genetic recombination in three dairy cattle populations from France, New-Zealand and the Netherlands. We identify 2,395,177 crossover (CO) events in sperm cells transmitted by 2,940 sires ... [more ▼]

We herein study genetic recombination in three dairy cattle populations from France, New-Zealand and the Netherlands. We identify 2,395,177 crossover (CO) events in sperm cells transmitted by 2,940 sires to 94,516 offspring, and 579,996 CO events in oocytes transmitted by 11,461 cows to 25,332 offspring. When measured in identical family structures, the average number of CO in males (23.3) was found to be larger than in females (21.4). The heritability of global recombination rate (GRR) was estimated at 0.13 in males and 0.08 in females. The genetic correlation was equal to 0.66, indicating that shared variants are influencing GRR in both genders. Haplotype-based genome-wide association studies revealed seven genome-wide significant QTL. Variants identified by next-generating sequencing in 5 Mb windows encompassing the QTL peaks were imputed in order to perform a sequence-based association analysis. For four QTLs, we identified missense mutations in genes known to be involved in meiotic recombination among the most significantly associated variants. The P259S variant identified in RNF212 had already been reported, whereas missense mutations in MLH3 (N408S), HFM1 (S1189L), MSH5 (R631Q), MSH4 (C342Y) and a second in RNF212 (A77T) are new. Surprisingly, variants previously identified in REC8 were not associated with a QTL detected on BTA10 whereas variants in RNF212B, a paralog of RNF212, showed much stronger association with the phenotype in this region. This suggests that RNF212B might be involved in the recombination process. Most of the identified mutations had significant effects in both genders with three of them accounting each for approximately 10% of the genetic variance in males (the allelic substitution effect being approximately equal to one additional CO per genome). Thus, a large fraction of the genetic variance is associated with missense mutations in genes known to be involved in meiotic recombination. Our results are very different from reports of recombination in other species. For instance, in human, recombination rate is higher in females, distinct variants affect recombination rate in males and females, and the genetic correlation is close to 0, whereas in cattle, we observed a higher recombination rate in males controlled by shared variants effective in both sexes. [less ▲]

Detailed reference viewed: 37 (2 ULg)
See detailHigher Needs for Enacted Knowledge. The case of Belgian Prison Governors
Dubois, Christophe ULg

Scientific conference (2017, April 27)

Considering that Belgian prison policy has been characterized by an increase of managerial and legal regulations in the last fifteen years, this rise of “inscribed knowledge” (Freeman & Sturdy, 2015 ... [more ▼]

Considering that Belgian prison policy has been characterized by an increase of managerial and legal regulations in the last fifteen years, this rise of “inscribed knowledge” (Freeman & Sturdy, 2015) leads to a sharper need of prison managers for “practical wisdom” (Chia and Holt, 2009). Two statements enlighten this paradoxical irony. Firstly, law and policy don't apply automatically, but must always be interpreted by human actors in relation to the situation. Secondly, the increase in legal and managerial demands reinforces prison governors’ more general inclinations to “satisficing” decisions (Simon, 1956). Drawing on two years of qualitative research with 30 Belgian prison governors, Christophe aims at analysing how prison governors are “enacting” prison policy and organisations (Weick, 1988), rather than being simply determined by it. [less ▲]

Detailed reference viewed: 15 (1 ULg)