Effect of handling in pre-weaning rabbits

[EN] The aim of this study was to investigate the effects of regular daily handling on weight gain and on the fear reaction towards a new environment and human beings in domestic kits (Tonic Immobility test: TI, Emergence test: ET). Two groups in the same environment and fed the same diet were analysed: handled group and control (17 litters, 9 kits/litter per group). No differences in weight gain were recorded. During ET at 33 days of age, handled kits took less time to enter the arena than control group kits. TI duration was shorter in handled kits, which required more inductions than the control group. It was found that minimal human contact imposed before nursing reduced the fear of humans in rabbit kits. Our handling method requires minimal contact and can be used to reduce fear and improve welfare in rabbits. Moreover, the short length of the handling procedure allows stockpersons to produce tamer rabbits, reducing stress levels.This research was funded by PRIN 2005 (MUR - Roma). We would like to thank the farm “Erminia Vezzoli” located in Covo (Bergamo, Italy).Zucca, D.; Redaelli, V.; Marelli, S.; Bonazza, V.; Heinzl, E.; Verga, M.; Luzi, F. (2012). Effect of handling in pre-weaning rabbits. World Rabbit Science. 20(2):97-101. doi:10.4995/wrs.2012.1083SWORD9710120

Probing ligand and cation binding sites in G-quadruplex nucleic acids by mass spectrometry and electron photodetachment dissociation sequencing

International audienceMass spectrometry provides exquisite detail on ligand and cation binding stoichiometries with a DNA target. The next important step is to develop reliable methods to determine the cation and ligand binding sites in each complex separated by the mass spectrometer. To circumvent the caveat of ligand derivatization for cross-linking, which may alter the ligand binding mode, we explored a tandem mass spectrometry (MS/MS) method that does not require ligand derivatization, and is therefore also applicable to localize metal cations. By obtaining more negative charge states for the complexes using supercharging agents, and by creating radical ions by electron photodetachment, oligonucleotide bonds become weaker than the DNA-cation or DNA-ligand noncovalent bonds upon collision-induced dissociation of the radicals. This electron photodetachment (EPD) method allows to locate the binding regions of cations and ligands by top-down sequencing of the oligonucleotide target. The very potent G-quadruplex ligands 360A and PhenDC3 were found to replace a potassium cation and bind close to the central loop of 4-repeat human telomeric sequences

Effect of environmental enrichment and group size on behaviour and live weight in growing rabbits

[EN] The aim of this research was to study the effects of group size and environmental enrichment on behaviour and growth of 108 hybrid growing rabbits (Oryctolagus cuniculus). We compared the behaviour (time budget and reactions to specific behavioural tests: "tonic immobility" and "emergence test") and live weight of growing rabbits housed in cages with a different number of rabbits per cage (2, 3 and 4; same density:14 rabbits/m2). Half of the cages were enriched with a wooden stick (Robinia Pseudoacacia, length: 20 cm ¿ diameter: 6 cm, cylindrical) hanging from the ceiling of the cage. The stick and number of animals per cage had no effect on weight gain or on behavioural tests responses. Interaction with the stick was significantly higher at the beginning of the growing period. Principal component analysis performed on the data for the whole period showed significant differences according to the treatments: increasing the number of rabbits per cage and introducing a wooden stick seemed to affect locomotor activity frequency and social interactions. Rabbits housed 3 and 4 per cage showed less lying behaviour and higher locomotor activity and sitting. The larger functional space allowance enabled rabbits to perform more natural behaviours compared to smaller cages (2 rabbits/cage). Environmental enrichment seems to be related to higher allogrooming behaviour frequency, which could indicate a social behaviour related to pheromonal olfactory stimulation and mutual recognition.Zucca, D.; Marelli, S.; Redaelli, V.; Heinzl, E.; Cardile, H.; Ricci, C.; Verga, M.... (2012). Effect of environmental enrichment and group size on behaviour and live weight in growing rabbits. World Rabbit Science. 20(2):89-95. doi:10.4995/wrs.2012.1082SWORD899520

Molecular phylogeny and diversification history of Prosopis (Fabaceae: Mimosoideae)

The genus Prosopis is an important member of arid and semiarid environments around the world. To study Prosopis diversification and evolution, a combined approach including molecular phylogeny, molecular dating, and character optimization analysis was applied. Phylogenetic relationships were inferred from five different molecular markers (matK-trnK, trnL-trnF, trnS-psbC, G3pdh, NIA). Taxon sampling involved a total of 30 Prosopis species that represented all Sections and Series and the complete geographical range of the genus. The results suggest that Prosopis is not a natural group. Molecular dating analysis indicates that the divergence between Section Strombocarpa and Section Algarobia plus Section Monilicarpa occurred in the Oligocene, contrasting with a much recent diversification (Late Miocene) within each of these groups. The diversification of the group formed by species of Series Chilenses, Pallidae, and Ruscifoliae is inferred to have started in the Pliocene, showing a high diversification rate. The moment of diversification within the major lineages of American species of Prosopis is coincident with the spreading of arid areas in the Americas, suggesting a climatic control for diversification of the group. Optimization of habitat parameters suggests an ancient occupation of arid environments by Prosopis species.Fil: Catalano, Santiago Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Vilardi, Juan Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Tosto, Daniela Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas; ArgentinaFil: Saidman, Beatriz Ofelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

Sequence selective naked-eye detection of DNA harnessing extension of oligonucleotide-modified nucleotides

DNA polymerases can efficiently and sequence selectively incorporate oligonucleotide (ODN)-modified nucleotides and the incorporated oligonucleotide strand can be employed as primer in rolling circle amplification (RCA). The effective amplification of the DNA primer by Φ29 DNA polymerase allows the sequence-selective hybridisation of the amplified strand with a G-quadruplex DNA sequence that has horse radish peroxidase-like activity. Based on these findings we develop a system that allows DNA detection with single-base resolution by naked eye.publishe

G-quadruplexes Sequester Free Heme in Living Cells

International audienc

Iso-FRET: an isothermal competition assay to analyze quadruplex formation in vitro

International audienceAlgorithms have been widely used to predict G-quadruplexes (G4s)-prone sequences. However, an experimental validation of these predictions is generally required. We previously reported a high-throughput technique to evidence G4 formation in vitro called FRET-MC. This method, while convenient and reproducible, has one known weakness: its inability to pin point G4 motifs of low thermal stability. As such quadruplexes may still be biologically relevant if formed at physiological temperature, we wanted to develop an independent assay to overcome this limitation. To this aim, we introduced an isothermal version of the competition assay, called iso-FRET, based on a duplex-quadruplex competition and a well-characterized bis-quinolinium G4 ligand, PhenDC3. G4-forming competitors act as decoys for PhenDC3, lowering its ability to stabilize the G4-forming motif reporter oligonucleotide conjugated to a fluorescence quencher (37Q). The decrease in available G4 ligand concentration restores the ability of 37Q to hybridize to its FAM-labeled short complementary C-rich strand (F22), leading to a decrease in fluorescence signal. In contrast, when no G4-forming competitor is present, PhenDC3 remains available to stabilize the 37Q quadruplex, preventing the formation of the F22 + 37Q complex. Iso-FRET was first applied to a reference panel of 70 sequences, and then used to investigate 23 different viral sequences

Polyheteroaryl Oxazole/Pyridine-Based Compounds Selected in Vitro as G-Quadruplex Ligands Inhibit Rock Kinase and Exhibit Antiproliferative Activity

International audienceHeptaheteroaryl compounds comprised of oxazole and pyridine units (TOxaPy) are quadruplex DNA (G4)-interactive compounds. Herein, we report on the synthesis of parent compounds bearing either amino side chains (TOxaPy-1− 5) or featuring an isomeric oxazole-pyridine central connectivity (iso-TOxapy, iso-TOxapy 1−3) or a bipyridine core (iso-TOxabiPy). The new isomeric series showed significant G4-binding activity in vitro, and remarkably, three compounds (iso-TOxaPy, iso-TOxaPy-1, and iso-TOxabiPy) exhibited high antiproliferative activity toward a tumor panel of cancer cell lines. However, these compounds do not behave as typical G-quadruplex (G4) binders, and the kinase profiling assay revealed that the best antiproliferative molecule iso-TOxaPy selectively inhibited Rock-2. The targeting of Rock kinase was confirmed in cells by the dephosphorylation of Rock-2 substrates, the decrease of stress fibers, and peripheral focal adhesions, as well as the induction of long neurite-like extensions. Remarkably, two of these molecules were able to inhibit the growth of cells organized as spheroids

DNA polymerase-catalyzed incorporation of nucleotides modified with a G-quadruplex-derived DNAzyme

We show that nucleotides which are modified with a G-quadruplex-derived DNAzyme are substrates for DNA polymerases. Based on this finding we developed a naked-eye detection system that allows the detection of single nucleotide variations in DNA