19,860 research outputs found
Immunological profiles of Bos taurus and Bos indicus cattle infested with the cattle tick, Rhipicephalus (Boophilus) microplus
No full textThe cattle tick, Rhipicephalus (Boophilus) microplus, is a major threat to the improvement of cattle production in tropical and subtropical countries worldwide. Bos indicus cattle are naturally more resistant to infestation with the cattle tick than are Bos taurus breeds, although considerable variation in resistance occurs within and between breeds. It is not known which genes contribute to the resistant phenotype, nor have immune parameters involved in resistance to R. microplus been fully described for the bovine host. This study was undertaken to determine whether selected cellular and antibody parameters of the peripheral circulation differed between tick-resistant Bos indicus and tick-susceptible Bos taurus cattle following a period of tick infestations. This study demonstrated significant differences between the two breeds with respect to the percentage of cellular subsets comprising the peripheral blood mononuclear cell population, cytokine expression by peripheral blood leukocytes, and levels of tick-specific immunoglobulin G1 (IgG1) antibodies measured in the peripheral circulation. In addition to these parameters, the Affymetrix bovine genome microarray was used to analyze gene expression by peripheral blood leukocytes of these animals. The results demonstrate that the Bos indicus cattle developed a stabilized T-cell-mediated response to tick infestation evidenced by their cellular profile and leukocyte cytokine spectrum. The Bos taurus cattle demonstrated cellular and gene expression profiles consistent with a sustained innate, inflammatory response to infestation, although high tick-specific IgG1 titers suggest that these animals have also developed a T-cell response to infestation
Complete mitochondrial genomes of Bos taurus and Bos indicus provide new insights into intraspecies variation taxonomy and domestication
No full textThe taurine and zebuine cattle breeds comprise the majority of the world cattle population but their taxonomic status is still controversial. The two forms of cattle are currently classified as Bos taurus and Bos indicus species and are differentiated primarily by the presence or absence of a hump. However, these two species hybridize readily, producing fully fertile offspring. We have determined and analyzed complete B. taurus and B. indicus mitochondrial genome sequences to investigate the extent of sequence divergences and to study their taxonomic status by molecular dating. The sequences encompassed 16,338 and 16,339 nucleotides, respectively, and differed at 237 positions. Estimated divergence times indicated that the two cattle lineages separated 1.7-2.0 million years ago. Combined phylogenetic analyses of 18 new and 130 previously reported extant B. taurus and B. indicus control region sequences with data from 32 archaeological specimens of the extinct wild aurochs (Bos primigenius) identified four major maternal lineages. B. primigenius haplotypes were present in all but the B. indicus lineage, and one B. taurus sequence clustered with B. primigenius P haplotypes that were not previously linked with domestic cattle. The B. indicus cluster and a recently reported new B. primigenius haplotype that represents a new lineage were approximately equidistant from the B. taurus cluster. These data suggest domestications from several differentiated populations of B. primigenius and a subspecies status for taurine (B. primigenius taurus) and zebuine (B. primigenius indicus) cattle.S. Hiendleder, H. Lewalski, A. Jank
Genome sequencing of the extinct Eurasian wild aurochs, Bos primigenius, illuminates the phylogeography and evolution of cattle
No full textBackground
Domestication of the now-extinct wild aurochs, Bos primigenius, gave rise to the two major domestic extant cattle taxa, B. taurus and B. indicus. While previous genetic studies have shed some light on the evolutionary relationships between European aurochs and modern cattle, important questions remain unanswered, including the phylogenetic status of aurochs, whether gene flow from aurochs into early domestic populations occurred, and which genomic regions were subject to selection processes during and after domestication. Here, we address these questions using whole-genome sequencing data generated from an approximately 6,750-year-old British aurochs bone and genome sequence data from 81 additional cattle plus genome-wide single nucleotide polymorphism data from a diverse panel of 1,225 modern animals.
Results
Phylogenomic analyses place the aurochs as a distinct outgroup to the domestic B. taurus lineage, supporting the predominant Near Eastern origin of European cattle. Conversely, traditional British and Irish breeds share more genetic variants with this aurochs specimen than other European populations, supporting localized gene flow from aurochs into the ancestors of modern British and Irish cattle, perhaps through purposeful restocking by early herders in Britain. Finally, the functions of genes showing evidence for positive selection in B. taurus are enriched for neurobiology, growth, metabolism and immunobiology, suggesting that these biological processes have been important in the domestication of cattle.
Conclusions
This work provides important new information regarding the origins and functional evolution of modern cattle, revealing that the interface between early European domestic populations and wild aurochs was significantly more complex than previously thought
Dual origins of dairy cattle farming--evidence from a comprehensive survey of European Y-chromosomal variation
No full textBACKGROUND: Diversity patterns of livestock species are informative to the history of agriculture and indicate uniqueness of breeds as relevant for conservation. So far, most studies on cattle have focused on mitochondrial and autosomal DNA variation. Previous studies of Y-chromosomal variation, with limited breed panels, identified two Bos taurus (taurine) haplogroups (Y1 and Y2; both composed of several haplotypes) and one Bos indicus (indicine/zebu) haplogroup (Y3), as well as a strong phylogeographic structuring of paternal lineages. METHODOLOGY AND PRINCIPAL FINDINGS: Haplogroup data were collected for 2087 animals from 138 breeds. For 111 breeds, these were resolved further by genotyping microsatellites INRA189 (10 alleles) and BM861 (2 alleles). European cattle carry exclusively taurine haplotypes, with the zebu Y-chromosomes having appreciable frequencies in Southwest Asian populations. Y1 is predominant in northern and north-western Europe, but is also observed in several Iberian breeds, as well as in Southwest Asia. A single Y1 haplotype is predominant in north-central Europe and a single Y2 haplotype in central Europe. In contrast, we found both Y1 and Y2 haplotypes in Britain, the Nordic region and Russia, with the highest Y-chromosomal diversity seen in the Iberian Peninsula. CONCLUSIONS: We propose that the homogeneous Y1 and Y2 regions reflect founder effects associated with the development and expansion of two groups of dairy cattle, the pied or red breeds from the North Sea and Baltic coasts and the spotted, yellow or brown breeds from Switzerland, respectively. The present Y1-Y2 contrast in central Europe coincides with historic, linguistic, religious and cultural boundaries.
Recycled Glass Mixtures as Cast Glass Components for Structural Applications, Towards Sustainability
No full textThe problem of sustainability represents one of the most important issues that the world has to face nowadays, not only in terms of energy consumption and of the consequent CO2 emissions, but also in terms of material waste streams that end in landfill. 38 million tons of glass waste are produced every year in the European Union and new targets have been set for 2020 towards a more sustainable management of such wastes. Nowadays, only the container glass industry has reached a considerable recycling rate, while for all the other sectors we are still witnessing downgrading processes. Looking at the world of construction, glass has been more and more employed as a structural material thanks to its high transparency and compression strength. Although the use of glass can be attractive under multiple aspects and its production is continuously increasing, once employed as a construction element, it is rarely reused or recycled due to the high-quality requirement demanded to the industry of production. Nevertheless, besides its main applications as a 2-dimensional element, the new technology of cast glass has been recognised as a potential mean of glass recycling. Here, glass is designed and used under the form of repetitive 3-dimensional units assembled in a whole geometrical shape. In fact, thanks to its higher load-bearing capacity under monolithic shapes, this glass can admit less restrictions and potentially incorporate different types of waste. For this reason, the aim of this experimental work is to find a possible combination between glass families, specifically soda-lime, borosilicate and lead-crystal glass, to be recycled as cast glass components. Each type of glass was powdered or grinded under the form of cullet and different mixtures were prepared to be melted at temperatures of 970°C, 1120°C and 1200°C through the kiln-cast tecnique. Finally, an experimental splitting test was performed to define a force trend and a fracture behaviour for each sample. Some preliminary results have been achieved drawing the guidelines for a further investigation. Soda-lime-silica glass and lead-crystal glass mixture revealed to be the most compliant glass recipe with the required physical and mechanical properties, when reheated at 1120°C. The decrease in the melting temperature of the compound and the higher transparency given by the addition of lead glass revealed the potential benefit, in terms of sustainability, for future projects
Modeling the Austenite Ferrite Transformation by Cellular Automaton: Improving Interface Stability
No full textA three-dimensional mixed-mode cellular automaton model [C. Bos, M. G. Mecozzi, and J. Sietsma. Computational Materials Science 48.3 (2010): 692-699] for the austenite to ferrite transformation in low-carbon steel has been analyzed and improved. A comparison between the new and conventional model has been made and the improvements found are significant. Interface velocity is based on diffusion of carbon atoms and determined by the local density of carbon. A higher grain boundary carbon diffusion coefficient is applied. The conventional model has been revised and stabilized. Real dilatometry tests have been used to mirror the transformation behaviour of the model with reality. For a one-dimensional model it has been shown that the space-discretizing cellular automaton model converges to the space-continuous method of Murray-Landis.Applied MathematicsNumerical AnalysisElectrical Engineering, Mathematics and Computer Scienc
Polynomial Interpolation of Holomorphic Functions in C and C^N
No full textThis is a survey of this subject up to 1991
TIRF and its application to protein adsorption : electrostatics and orientation
No full textThe aim of the study in this thesis was to develop a method for determining the orientation of adsorbed protein molecules and to study the influence of the electrical potential of the interface on the interfacial properties of proteins, including their orientation.In the adsorption of proteins on solid surfaces many factors play a role. The most important are electrostatic and hydrophobic interactions between the protein molecules and the sorbent surface, and structural rearrangements in the protein molecules. From earlier studies it was concluded that proteins with regard to their adsorption behaviour can be roughly divided into "hard" and "soft" proteins. For the "hard" proteins structural changes upon adsorption are negligible and these proteins do not adsorb on hydrophilic surfaces unless there is electrostatic attraction. "Soft" proteins have a tendency to unfold partially upon adsorption and they adsorb on all kind of surfaces, irrespective of any electrostatic repulsion, partly caused by a gain of conformational entropy during adsorption.The orientation of adsorbed protein molecules plays an important role in the effectivity and the development of immunoassays and diagnostic tests. One can imagine that if the orientation of an antibody (or enzyme) is not the right one, no recognition of the antigen (or substrate) occurs. Therefore, either much research is done to develop methods to adsorb antibodies and enzymes in the proper orientation or in ways to steer the adsorption process. In the development of biosensors knowledge of and insight into the adsorption process and the orientation of the adsorbed proteins molecules (used as the selector molecules) on inorganic materials also play essential roles.In this study two optical techniques have been used: Total Internal Reflection Fluorescence (TIRF) and reflectometry. With both techniques it is possible to monitor quantitatively and qualitatively the adsorption process of proteins in situ.TIRF has been used over the past 20 years for the measurement of protein adsorption kinetics and adsorbed amounts, and to study the exchange of proteins between sorbent surface and solution. A relatively new research topic for which TIRF is used is to obtain information on the orientation of adsorbed (protein) molecules. The principle of TIRF is as follows: A light beam is totally reflected at an interface between two media I and 2 with the refractive index of medium I higher than that of medium 2, and the angle of incidence exceeding its critical angle value. Due to interference between the incident and the reflected light beam an evanescent wave penetrates into medium 2. The amplitude of this electromagnetic wave decays exponentially with distance normal to the interface. The penetration depth of this wave depends on the wavelength of the light used, and the refractive indices of the media. For visible light striking a quartz/water interface it is in the order of 100 nm. If medium 2 consists of a solution with fluorescent molecules, the evanescent wave will excite the molecules that are close enough to the interface; the emitted fluorescence is detected. In the case of adsorption and not too high bulk concentrations, the fluorescence signal is almost completely stemming from molecules in the adsorption layer.With the optical technique reflectometry the adsorption of molecules on an (optically flat) solid surface can be monitored. A linearly polarized light beam is reflected from the adsorbing surface, and the reflected beam is split into its parallelly and perpendicularly polarized components. The intensity ratio between these two components is measured continuously. This ratio changes upon adsorption, and after calibration the adsorbed amount (mass/area) is obtained.In this work TIRF has been used for the determination of the orientation distribution of adsorbed molecules. Therefore, the existing theory had to be extended (chapter 2). Cytochrome c has been chosen as a model protein to test and illustrate the method, because of its welldocumented crystallographic structure and its well-characterized physicalchemical properties. Furthermore, cytochrome c has a chromophoric group which can be made fluorescent by removing the Fe-atom. The protein without the Fe-atom is called porphyrin cytochrome c. From various literature data it is inferred that the native cytochrome c molecule is rather structure-stable. Another interesting feature of the protein is its relatively large electric dipole moment (325 Debye at pH 7), which might offer a possibility to influence the orientation in the adsorbed state by variation of the surface charge.The method for determination of the orientation of adsorbed molecules is based on the principle that by changing the polarization of the incident light beam the direction of the electric field component of the evanescent wave is modified. As a result the interaction between the transition dipole moment of the adsorbed molecules and the evanescent wave alters, which in turn, gives rise to a change in the fluorescence intensity. To obtain order parameters from which the orientation distribution can be reconstructed, one has to measure not only the intensity but also the polarization of the fluorescence as a function of the polarization of the incident light beam. The theory has been elaborated especially for orientation measurements on porphyrins and cytochrome c. In the porphyrin ring two transition dipole moments are lying perpendicularly to one another. For this system it is possible to study the orientation distribution in one orientation angle from the restricted information: the angle 0 between the plane of the porphyrin ring and the interface. The orientation distribution in θcan be reconstructed using the Maximum Entropy Method. With regard to the mobility of the adsorbed molecules, which might interfere with the orientation measurements, it is shown that rotational mobility much faster than the fluorescence lifetime would result in the disappearance of the fluorescence polarization.Firstly, some experiments with a simple porphyrin (tetramethyl-pyridiniurn porphyrin, H 2 TMPyP) have been performed (chapter 4). Prior to the orientation measurements, its adsorption behaviour was studied by reflectometry. For adsorption on silica from pure water, from 0.01 M phosphate buffer pH 7 and from 0.1 M KNO 3 solution different adsorbed amounts have been found. From the TIRF orientation measurements satisfying results were obtained, although the reproducibility leaves still something to desire. The orientation distribution of adsorbed H 2 TMPyP molecules on silica depends on the concentration of porphyrin in the solution from which adsorption takes place. At low concentration, the H 2 TMPyP molecules are more or less randomly oriented, while at high concentrations a broad distribution around an angle of 46° between the porphyrin plane and surface was observed. The fact that the fluorescence is polarized and the results of measurements with different solution viscosities show that the mobility of the adsorbed porphyrin molecules is on a much larger time scale than the fluorescence life time (5 ns).To study the influence of the electrical potential (charge) of the sorbent surface on the adsorption behaviour of proteins, a semi-conducting indium tin oxide (ITO) surface was used. This material was deposited in a thin layer (120- 140 run) on glass or silicium plates. The ITO surfaces have been characterized by streaming potential measurements, scanning electron microscopy, atomic force microscopy and resistance measurements. The results have been described in chapter 3.The adsorption behaviour of various proteins (serum albumin, lysozyme, ribonuclease A, superoxide dismutase, myoglobin and α-lactalbumin) as a function of an externally imposed interfacial potential has been studied using reflectometry (chapter 5). The sorbent surface was again a semi-conducting ITO layer deposited on a silicium wafer. The results obtained at the equilibrium potential as a function of pH suggest that electrostatic interactions play a decisive role in the adsorption of structurestable proteins on hydrophilic surfaces. On the other hand, protein adsorption is found to be hardly affected by externally imposed interfacial potentials, irrespective of the structure-stability of the protein. The cause for the apparent contradiction in these results must be that in both experimental approaches, but in different ways, together with the electrostatic interactions other properties of the system are also varied. (For example, on changing the pH, the net charge of the protein molecules changes, but also their structure-stability; together with increasing surface potentials, the surface becomes more hydrophilic; and, in the case a constant potential is externally applied, the adsorbing protein molecules may largely adapt their properties.) Therefore it is difficult to assess the importance of the contribution of electrostatic interactions in the process of protein adsorption. Presumably, in the past protein adsorption as a function of the pH has been interpreted in a too simplified manner, overestimating the role of electrostatic interactions.In chapter 6 the adsorption behaviour of native and porphyrin cytochrome c was the subject of study. Special attention is given to the adsorbed amounts, the adsorption kinetics and the influence of externally applied potentials for both forms of cytochrome c and the orientation of adsorbed porphyrin cytochrome c molecules. It was shown that the adsorption behaviour of native cytochrome c resembles that of structurestable proteins such as lysozyme and ribonuclease. In many aspects porphyrin cytochrome c behaves the same as the native form. However the adsorbed amounts at pH 7 and 10 are much higher. The adsorbed amounts and adsorption kinetics of both forms of cytochrome c are found to be hardly affected by externally imposed potentials. With regard to the orientation measurements it was not possible to interpret the data in terms of orientation distribution functions because of the scatter in the results.This spread is mainly caused by the low signal to noise ratio. Improvement of this ratio is difficult because of photo-deterioration of the adsorbed protein molecules. However, the total fluorescence as a function of the polarization angle of the incident light beam points to orientation distributions which do not depend on the surface coverage and cannot be influenced by imposing an electrical potential on the sorbent surface.In summary, in this work it is shown that TIRF is a suitable technique to determine orientation distributions of adsorbed fluorescent molecules. Further-more, it was found that it is not (or hardly) possible to influence the adsorption behaviour of proteins, irrespective of their structural stability, by externally imposing an electrical potential to the sorbent surface.PerspectivesIn this work we have developed a method to obtain the orientation distributions of adsorbed chromophores by making use of the optical technique TIRF. The results obtained with a simple porphyrin show that the method works. So far, application of this method to adsorbed proteins is limited, since the protein should be structure-stable upon adsorption and carry a fluorescent group. It was not possible to reconstruct the orientation distribution of cytochrome c molecules because of the scatter in the order parameters obtained. In order to obtain the orientation distribution it is necessary to improve the signal to noise ratio of the fluorescence measurements. This could be done by measuring the fluorescence over a longer time. In the case of cytochrome c this fails because the adsorbed molecule appears to undergo structural rearrangements in the presence of light.For other structure-stable proteins, it might be possible to determine the orientation distribution in the adsorbed state. If the molecules do not have a fluorescent group, one might consider to label them; prerequisite is that the fluorescent label is fixed in the molecule with a known orientation to the rest of the molecule. However, a caveat is that introducing a fluorescent label might lead to structural changes within the molecule and hence influence the adsorption behaviour of the protein. Another possibility to obtain orientation distributions of adsorbed proteins with TIRF is to make use of the fluorescence of the aromatic amino acids tryptophan and tyrosine. These amino acids have a fixed place in the structure and their excitation wavelength is in the UV. This sets higher demands to the optical parts in the experimental set-up. Furthermore, the presence of more than one of these amino acids can cause energy transfer from one amino acid to the other. As a result it is not known where the fluorescence is stemming from and the information about the orientation is lost. Another disadvantage is that protein molecules might be damaged by the UV light.Meanwhile, the TIRF method for determining the orientation of adsorbed chromophores is already used in a study concerning the development of "organic" solar energy cells, conducted in the Department of Molecular Physics of the Wageningen Agricultural University. In this study porphyrin molecules are used as sensitizers to generate charge carriers in a semiconducting surface. The adsorption of porphyrins on this surface, especially their orientation, is a prominent factor determining the efficiency of the system. The more parallel the molecules lie on the surface, the higher the energy transfer is. The results obtained here with H 2 TMPyP and presented in chapter 4 were promising enough to use the method for studying the orientation of several derivatives of H 2 TMPyP.In our own department the method is now also used to investigate the order in Langmuir-Blodgett (LB) layers of phospholipids, which stand model for biological membranes. In the near future the structure and permeability of such phospholipid layers will be studied as a function of the electrical potential of the substrate. To that end, the LB layers will be deposited onto optically transparent conducting ITO films on quartz slides. With different fluorescent probes it is hoped that information on the rotational mobility and/or reorientation is obtained.Integration of TIRF with time-resolved fluorescence measurements can provide more detailed information on the structure and orientation of adsorbed molecules and on dynamic processes taking place on the time scale of fluorescence, e.g. rotation of the whole molecule or parts of it.In conclusion, the potentials of TIRF to study orientations are not exhausted
Organizing the unfinalizable. A critical inquiry into the ‘responsible organization’ of a forensic assertive community treatment practice
No full textContains fulltext :
208079.pdf (Publisher’s version ) (Open Access)Radboud University, 01 november 2019Promotor : Bos, R. ten Co-promotor : Groß, C
Marketing Digital Products at Witteveen+Bos
No full textThis graduation thesis for the master Strategic Product Design at the Delft University of Technology is written as a research and advice report for the civil engineering and advice agency Witteveen+Bos. More specifically for the Digital Acceleration product-market combination (PMC). The report answers the following question: “Is Witteveen+Bos as an organization structurally fit for developing, maintaining and marketing digital products?”...https://youtu.be/PAFp5PyltcA Link to video showcaseStrategic Product Desig
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