87,132 research outputs found
Genetic analysis of production, immunity and behaviour in laying hens
No full textThe new regulations about the husbandry of laying hens and the so-called genomic revolution offer both opportunities and challenges for the breeding of layers. Hens are currently housed mainly in battery cages of 4 individuals each. Following recent developments of the communitarian legislation, many countries will soon adopt furnished cages or non-cage systems, which will lead to larger groups of hens. Also, beak-trimming will be prohibited in EU countries in the near future. Advancements in sequencing technology are making an always greater number of genetic markers available at increasingly cheaper prices, making genome-wide studies possible and helping geneticists to start unraveling the mystery of the genetic make-up of animals, which until a few years ago was considered a black-box. This thesis touches upon the impact of such innovations on the breeding of laying hens. Use of pooled data in the genetic evaluation of laying hens Hens are usually housed in cages and therefore pooled instead of individual egg records are often available: a pooled egg record is the total production of a cage, when the egg production of the individual hens is unknown. Current selection schemes are carried out in nucleus herds where hens are housed individually, so that egg production of individual birds can be recorded and used for genetic evaluations. Based on this information sires and dams are selected. Such a selection scheme based on individually housed hens introduces a discrepancy between the environment where hens are selected and the environment in which hens are kept for commercial egg production (group housing). Selecting animals in one environment and using them in a different environment might lead to genotype x environment interaction (Besbes and Ducroq, 2003), thereby reducing the realized response to selection. Future husbandry conditions, with larger groups of hens or hens housed in furnished cages might make this problem even worse. A method to use pooled data in the genetic evaluation of laying hens would therefore be of interest. In Chapters 2 and 3 of this thesis it is described how to use pooled records for the estimation of heritability and breeding values. In chapter 2 the use of individual and pooled observations is compared. Individual body weights of hens at different ages were available: these were then pooled by cage in order to create pooled records. Heritabilities estimated from pooled and individual data correlated well: the standard error of estimates based on pooled records was however about twice that of estimates based on individual records. The accuracy of EBVs from pooled data is lower than the accuracy of EBVs from individual data; in the case of sires with at least 10 offspring the reduction in accuracy was about 23%. This loss of precision in estimating genetic parameters and breeding values is understandable considering that pooled records are a less detailed of information. However, this lower accuracy should be interpreted in the context of direct vs indirect selection. The breeding goal is the trait under commercial conditions (group housing), and if testing is under individual housing, the genetic correlation between group and individual housing is relevant. The ratio of the selection response for direct and indirect selection is a function of the accuracies for both situations, the standard deviations of the traits and the genetic correlation between the traits (Falconer, 1989). Similarly, the ratio between accuracies based on pooled and individual data provides a threshold for the genetic correlation between individual and group housing below which pooled data would result in a greater selection response. In practical breeding also the costs of individual housing relative to the costs of group housing are relevant. Since group housing is cheaper than individual housing, more selection candidates could be tested for the same level of costs. This would in turn result in higher selection intensity and larger response to selection. In chapter 3 the method of analyzing pooled data developed in chapter 2 was compared with an approximation consisting in assigning cage means to each hen in a cage, then treating them as individual observations. Cross-validation was used to compare the two methods: the method developed in Chapter 2 performed consistently better than the approximate method in terms of predicting ability. In the general discussion, finally, it was described how to estimate genetic and phenotypic correlations from pooled data. Across-line association studies for immune response and feather pecking behaviour The great number of genetic markers available at increasingly lower prices has been fostering developments in genomic research. Association studies between genetic markers and phenotypes are typically conducted within populations (breeds, or lines): the amount of LD conserved in a population is exploited using high marker density, such as SNP chips, and markers relatively close to QTLs are expected to show significant effects in association studies. In this thesis we propose to take it one step further and perform association studies across lines. This requires higher marker density but increases the resolution. The amount of LD conserved across lines is expected to be lower than within lines and the phase of the marker-phenotype association might be different in the different lines. On the other hand markers that happen to show significant effects in an across-line association study are likely to be close to the QTL. These issues in conducting marker-phenotype association studies across populations were addressed in Chapters 4 and 5 of this thesis, where it was shown how to deal with multiple populations when analyzing hens from 9 different genetic lines of White Leghorn and Rhode Island Red origin genotyped for a panel of 1536 SNP (Single Nucleotide Polymorphism) markers. The traits analysed were immunological parameters and plumage damage due to feather pecking behaviour, two classes of traits for which, given that they have relatively low heritability and are difficult and expensive to measure, genomic information may be particularly valuable. Immunological parameters might be used in selection programmes aimed at improving disease resistance of laying hens, while information on the genetic background of feather pecking behaviour can be useful in reducing problems due to this behavioural disorder of layers. Under future husbandry conditions susceptibility to infectious diseases and feather pecking are expected to become more serious problems: both aspects of layer production are in fact related to the number of individuals that interact with each other, which will increase as a result of the application of the EU directive 1999/74/EC. In addition, the ban of beak-trimming will make it more difficult to control the consequences of feather pecking (plumage damage, cannibalism, mortality). Genetic selection might represent an appealing addition to the current control measures. The association studies identified several regions of interest. The gene for interleukin 17 (IL17), on chromosome 3, was found to be associated with natural and acquired antibody titres, and with the classical and alternative pathways of complement activation. The major histocompatibility complex (MHC) genes on chromosome 16 showed significant association with natural and acquired antibody titres and classical complement activity. The interleukin 12B gene (IL12B) on chromosome 13 was associated with natural antibody titres. As for feather pecking behaviour, a role of the gene for the serotonin receptor 2C (HTR2C) on chromosome 4 was found. This supports existing evidence of a prominent involvement of the serotonergic system in the modulation of this behavioural disorder in laying hens. The genes for IL9, IL4, CCL4 and NFKB were found to be associated to plumage condition, revealing relationships between the immune system and behaviour. <br/
Innovative technologies for knee rehabilitation in subjects with anterior cruciate ligament injuries.
No full textIntroduction Recent theoretical studies indicate that during leg extension exercises
the tibiofemoral shear forces and the ACL strain-forces can be externally modulated.
These modulations can be obtained by a controlled displacement of the application
point of the resistance force along the lower-leg during the knee flexion/extension
(Biscarini, 2008), or through an external compressive force applied on the knee joint
(Fleming et al., 2007). Methods We have designed and developed two innovative
leg extension prototypes which integrate these functions. In the first prototype, the
resistance lever of a standard leg-extension equipment was replaced by a linear
guide along with the resistance pad can slide. The pad movement along the guide is
generated by an electric motor controlled by an angular encoder placed on the
rotation axis of the equipment, and a linear encoder installed along the linear guide.
A feedback control algorithm was developed to provide an accurate and fast
dynamic control of the pad positioning. In the second prototype, a foot platform
was inserted at the distal side of the resistance lever to exert a controlled axial
compression on the lower limb during the exercise. Two protocols for surface EMG
and imaging techniques measurement were designed to assess and compare the
levels of hamstring co-contraction (which is known to represent a protective factor
for the ACL) and the anterior tibial translation (which is proportional to the ACL
strain-force), during the exercise with these two new prototypes and the standard
equipment, at different levels of external resistances. Each trial was also repeated
encouraging the subjects to intentionally enhance hamstring co-activation during
the exercise. Results EMG data collected on seventeen healthy subjects indicate that
hamstring co-activation is not influenced by pad movement and axial compression.
However, the hamstring co-activation was increased from two to four times when
the subjects were encouraged to intentionally co-contract the knee flexor muscles
during the leg extension exercise. Discussion Intentional hamstring co-contraction in
leg extension exercises can be an effective strategy for ACL protection and
tibiofemoral joint stability in ACL deficient patients, and in rehabilitation programs
after cruciate ligament reconstruction. Further investigations with imaging
techniques will definitely asses the effectiveness of the two prototypes. References
Biscarini (2008). Medical Engineering & Physics 30(8), 1032-1041 Fleming et al.
(2003). Am J Sports Med 31(5), 701-70
Digital PCR as New Approach to SNP Genotyping in Sugar Beet
No full textReal-time PCR (qPCR) allelic discrimination and high-resolution melting (HRM) methods are widely adopted for the detection of single nucleotide polymor- phisms (SNP). Digital PCR (dPCR) is a new method recently proposed for the detection of low-frequency and/ or rare SNP. The molecular marker SNP_BvBTC1 is used in sugar beet to distinguish between annual and biennial flowering plants. The CC genotype at this SNP locus is associated with biennial beets, while the CA and AA genotypes are typically found in annual beets. In this study, we compared the sensitivity of qPCR, HRM and dPCR in detecting the allele A from two pools of bulk beet DNA composed of 90 biennial ? 10 annual plants (B1) and 99 biennial ? 1 annual plant (B2), respectively. All annual plants were found to have the AA genotype. qPCR could not detect allele A in either the B1 or B2 pool and HRM detected allele A only at moderate frequencies (10 %), in the B1 pool. dPCR, on the contrary, was able to detect allele A in both pools. We therefore concluded that dPCR is a suitable method for the quantitation of SNP_BvBTC1 within bulked DNA samples of sugar beet
Electric Field Effects on Short Fibrils of A beta Amyloid Peptides
No full textAmyloid fibrils are highly ordered protein aggregates, which are associated with many neurodegenerative diseases. The assembling dynamics of monomeric beta-amyloid peptides, A beta, into small aggregates (and then into long fibrils) is still debated and has become a hot topic. In this study, we conducted molecular dynamics simulations in explicit water of small A beta protofibrils (from monomer to pentamer) under the perturbation of an externally applied electric field with the aim of investigating the fundamental molecular interactions involved in the aggregation mechanism. Dynamics of small adducts of A beta(16-42) in the presence of an electric field, which was shown before to accelerate the conformational change of a single molecule, indicate that the structural resilience increases with the number of molecules in the aggregate. In particular, for 50 ns, the pentamer shows an enhanced stability in secondary structure, number of hydrogen bonds, and number of salt bridges, even in the presence of the field perturbation. The resilience to the field perturbation is linked to the variation of the induced dipole moment of the aggregates that tends to level off very rapidly with the growing number of molecules, thereby reducing the energy available per molecule to produce structural changes. The results also show that in the presence of the field the stability of the hydrophobic second beta-sheet (32, residues 31-42) is higher than that of the first one (beta 1, residues 18-26). In particular, we identify Gly33, Gly37, and Met35 as the most important residues that stabilize the intermolecular packing and may act as nucleation sites for fibrillization. Furthermore, dynamics of the full-length A beta(1-42) pentameric aggregate, which include the highly charged random coil residues 1-15, confirmed the key role of the second hydrophobic core in the protofibril structure
Generalized parametric prediction model of the mean radiative temperature for microwave slant paths in all-weather condition
No full textThe mean radiative temperature (Tmr) is a key function controlling the sky noise temperature in microwave receiving systems. A generalized parametric prediction (GPP) model of Tmr for microwave slant paths in all-weather conditions is formulated and presented. The proposed GPP model is aimed at being multifrequency and surface-temperature scaled, valid for elevation angles from 5° to 90° and for frequencies ranging from 5 to 95 GHz within the three transmission windows delimited by the water vapor and the oxygen absorption peaks. The core of the GPP model is a parametrization driven by a physically based radiative transfer approach taking into account extinction, emission, and multiple scattering. The expression of Tmr is normalized to the surface temperature of the considered site. The GPP model is verified with measurements available from the multiinstrument Italian Satellite (ITALSAT) campaign in Spino d'Adda, Milan, Italy, in 1994-1997, obtaining a fractional mean error ranging from 0.045 to 0.068. A comparison of the GPP model with the current ITU-R model shows a reduction in the root mean square error up to about 20 and 30 K, depending on the considered frequency
"A theoretical framework for the interpretation of STM images of adsorbates"
No full textA theoretical formalism for the interpretation of STM images of adsorbates is developed by approaching the calculation of the observed current as a transport problem in quantum statistical mechanics. The STM configuration is treated as a system of three groups of states - the substrate, the adsorbate and the tip - in contact with a thermal reservoir, with which it exchanges energy. A new definition of current is introduced, and shown to be related to that given in the traditional transfer Hamiltonian approach. The transport instrument used for the description is the stochastic Liouville equation, known to have the advantage of allowing the incorporation of thermal effects as well as arbitrary degree of coherence in the quantum transport. Some preliminary calculations of STM images of simple adsorbate models are presented
3D Hierarchical Porous TiO2 Films from Colloidal Composite Fluidic Deposition
No full textWe use a "structure director" colloidal composite to fabricate porous titanium oxide films having a hierarchical pore architecture consisting of mesopores regularly distributed in the macropore shell. The colloidal composite consists of polystyrene beads coated with (ammonium lactate)titanium dihydroxide deposited by means of a fluidic technique. The pore properties and interconnections are controlled at different length scales: a macroscale, which is imposed by the polystyrene beads; a mesoscale, which is controlled by the composition and by the thermal history of the composite; a nanometer-scale, controlled by the nanocrystal sintering in air. Our approach can be extended to a wide class of water-soluble metal oxide precursors; therefore, it opens interesting perspectives for "bottom-up" nanotechnology of functional arrays and devices
Double layer capacitance measured by organic field effect transistor operated in water
No full textPentacene ultra thin film transistors were exposed to water and operated with a conventional silicon/silicon oxide bottom gate and an electrolyte top gate controlled by a working electrode. The transistors are highly sensible (mu V) to the electrochemical potential of the aqueous electrolyte. We show that dual gate operation permits the measurement of the double layer capacitance, C-DL = 14.6 mu F/cm(2). The device exhibits a fast (4.6 ms) and stable response, without bias stress as opposed to conventional bottom gate operations, when controlled with the electrolyte gate. These features make the device a promising candidate for potentiometric transducers required for non-invasive electrophysiology
Insights into genetic diversity, runs of homozygosity and heterozygosity-rich regions in maremmana semi-feral cattle using pedigree and genomic data
No full textSemi-feral local livestock populations, like Maremmana cattle, are the object of renewed interest for the conservation of biological diversity and the preservation and exploitation of unique and potentially relevant genetic material. The aim of this study was to estimate genetic diversity parameters in semi-feral Maremmana cattle using both pedigree-and genomic-based approaches (FIS and FROH), and to detect regions of homozygosity (ROH) and heterozygosity (ROHet) in the genome. The average heterozygosity estimates were in the range reported for other cattle breeds (HE = 0.261, HO = 0.274). Pedigree-based average inbreeding (F) was estimated at 4.9%. The correlation was low between F and genomic-based approaches (r = 0.03 with FIS, r = 0.21 with FROH), while it was higher between FIS and FROH (r = 0.78). The low correlation between F and FROH coefficients may be the result of the limited pedigree depth available for the animals involved in this study. The ROH islands identified in Maremmana cattle included candidate genes associated with climate adaptation, carcass traits or the regulation of body weight, fat and energy metabolism. The ROHet islands contained candidate genes associated with nematode resistance and reproduction traits in livestock. The results of this study confirm that genome-based measures like FROH may be useful estimators of individual autozygosity, and may provide insights on pedigree-based inbreeding estimates in cases when animals’ pedigree data are unavailable, thus providing a more detailed picture of the genetic diversity
Organic Bioelectronics for Regenerative Medicine
No full textElectronic transducers of neuronal cellular activity are important devices in neuroscience and neurology. Organic field-effect transistors (OFETs) offer tailored surface chemistry, mechanical flexibility, and high sensitivity to electrostatic potential changes at device interfaces. These properties make them attractive for interfacing electronics to neural cells and performing extracellular recordings and stimulation of neuronal network activity.
Here I want to present an emerging area of interest where the OFET is used as a gauge to supply a variety of electrical, chemical and electrochemical stimuli to neuronal cells, in an effort to stimulate their plasticity else to differentiate neuronal stem cells into neurons. I will overview the progresses of an ongoing EU project, “Implantable Organic Nanoelectronics” (I-ONE-FP7) which is aimed to the use of organic electronics in implantable devices for the treatment of the spinal cord injury (SCI). The project is presently at midterm, and I will highlight the advances to date and discuss the direction of further development towards in-vivo experiments on animal model of the SCI.
This work involves collaboration of several partners, that I would like to acknowledge through the principal investigators: S. Pluchino (Univ. of Cambridge), M. Berggren and D. Simon (Univ. Linkoeping), F. Zerbetto and S. Rapino (Univ. of Bologna), P. Greco (Scriba Nanotecnologie Srl Bologna), L. Occhipinti (ST Microelectronics Catania), D. Vuillaume (CNRS, Lille), R. Garcia (CSIC Madrid), H. Gomes (Univ. do Algarve), R. Frycek (Amires Sarl, Neuchatel), E. Cerna and V. Velebny (Contipro Dolni Dobrouc), T. Cramer, S. Casalini, F. Valle (CNR-ISMN Bologna), G. Foschi, C. A. Bortolotti, N. Dorigo (UNIMORE).
This work is supported by EU NMP Project I-ONE Grant Agreement n. 280772
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