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Search Results: 1 - 10 of 1473 matches for " Christiane Schnee "
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Assessment of a novel multiplex real-time PCR assay for the detection of the CBPP agent Mycoplasma mycoides subsp. mycoides SC through experimental infection in cattle
Christiane Schnee, Martin Heller, J?rg Jores, Herbert Tomaso, Heinrich Neubauer
BMC Veterinary Research , 2011, DOI: 10.1186/1746-6148-7-47
Abstract: The assays detected 49 MmmSC strains from diverse temporal and geographical origin, but did not amplify DNA from 82 isolates of 20 non-target species confirming a specificity of 100%. The detection limit was determined to be 10 fg DNA per reaction for the MSC_0136 assay and 100 fg per reaction for the MSC_1046 assay corresponding to 8 and 80 genome equivalents, respectively. The diagnostic performance of the assay was evaluated with clinical samples from 19 experimentally infected cattle and from 20 cattle without CBPP and compared to those of cultivation and a conventional PCR protocol. The two rt-PCR tests proved to be the most sensitive methods and identified all 19 infected animals. The different sample types used were not equally suitable for MmmSC detection. While 94.7% of lung samples from the infected cohort were positively tested in the MSC_0136 assay, only 81% of pulmonal lymph nodes, 31% of mediastinal lymph nodes and 25% of pleural fluid samples gave a positive result.The developed multiplex rt-PCR assay is recommended as an efficient tool for rapid confirmation of a presumptive CBPP diagnosis in a well-equipped laboratory environment.Contagious bovine pleuropneumonia (CBPP) caused by Mycoplasma mycoides subsp. mycoides SC (MmmSC) is a disease of cattle affecting the respiratory tract of animals. It is manifested by fever, anorexia, cough, and dyspnoea. Macropathological examinations show gross lesions in the lung including marbling, thickened interlobular septa and sequestra. However, clinical and pathological signs are not always evident, and chronically infected animals might act as carriers and source of infections. Today the disease is mainly confined to sub-Saharan Africa where it causes severe economic losses. As a result of rigid control measures and a consequent stamping out policy, Europe has been CBPP free since the late 1990s. Even so, the risk of re-introducing CBPP remains high. In case of a CBPP outbreak in non-endemic regions caused by an
Localization of sesquiterpene formation and emission in maize leaves after herbivore damage
Tobias G K?llner, Claudia Lenk, Christiane Schnee, Sabrina K?pke, Peter Lindemann, Jonathan Gershenzon, J?rg Degenhardt
BMC Plant Biology , 2013, DOI: 10.1186/1471-2229-13-15
Abstract: In this study, we restricted herbivore feeding to small sections of the maize leaf with the aim of determining the patterns of volatile sesquiterpene emission throughout the damaged leaf and in neighboring leaves. Sesquiterpene volatiles were released at high rates from damaged leaves, but at much lower rates from neighboring leaves. Release was restricted to the site of damage or to leaf sections located apical to the damage, but was not seen in sections basal to the damage or on the other side of the midrib. The emission pattern correlated well with the transcript pattern of the respective sesquiterpene synthase genes, tps10 and tps23, implying that biosynthesis likely occurs at the site of emission. The concentrations of jasmonic acid and its leucine derivative were also elevated in terpene-emitting tissues suggesting a role for jasmonates in propagating the damage signal.In contrast to other defense reactions which often occur systemically throughout the whole plant, herbivore-induced sesquiterpene production in maize is restricted to the wounding site and distal leaf parts. Since the signal mediating this reaction is directed to the leaf tip and cannot propagate parallel to the leaf axis, it is likely connected to the xylem. The increasing gradient of volatiles from the tip of the leaf towards the damage site might aid herbivore enemies in host or prey finding.The emission of volatiles by plants allows them to interact with other organisms at a distance. For example, many plant species emit floral volatiles which have diverse functions in pollinator attraction and repulsion [1]. Volatiles are also released from vegetative plant organs, especially after herbivore damage. Vegetative volatiles can function as attractants for enemies of herbivores [2] and have been suggested to serve as direct defenses against herbivores [2], as defenses against pathogens [3], as protectants against abiotic stress, and as signals in intra- and inter-plant communication [4]. However
The Origin of the ‘Mycoplasma mycoides Cluster’ Coincides with Domestication of Ruminants
Anne Fischer, Beth Shapiro, Cecilia Muriuki, Martin Heller, Christiane Schnee, Erik Bongcam-Rudloff, Edy M. Vilei, Joachim Frey, Joerg Jores
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0036150
Abstract: The ‘Mycoplasma mycoides cluster’ comprises the ruminant pathogens Mycoplasma mycoides subsp. mycoides the causative agent of contagious bovine pleuropneumonia (CBPP), Mycoplasma capricolum subsp. capripneumoniae the agent of contagious caprine pleuropneumonia (CCPP), Mycoplasma capricolum subsp. capricolum, Mycoplasma leachii and Mycoplasma mycoides subsp. capri. CBPP and CCPP are major livestock diseases and impact the agricultural sector especially in developing countries through reduced food-supply and international trade restrictions. In addition, these diseases are a threat to disease-free countries. We used a multilocus sequence typing (MLST) approach to gain insights into the demographic history of and phylogenetic relationships among the members of the ‘M. mycoides cluster’. We collected partial sequences from seven housekeeping genes representing a total of 3,816 base pairs from 118 strains within this cluster, and five strains isolated from wild Caprinae. Strikingly, the origin of the ‘M. mycoides cluster’ dates to about 10,000 years ago, suggesting that the establishment and spread of the cluster coincided with livestock domestication. In addition, we show that hybridization and recombination may be important factors in the evolutionary history of the cluster.
A Novel Rapid DNA Microarray Assay Enables Identification of 37 Mycoplasma Species and Highlights Multiple Mycoplasma Infections
Christiane Schnee, Samuel Schulsse, Helmut Hotzel, Roger D. Ayling, Robin A. J. Nicholas, Evelyn Schubert, Martin Heller, Ralf Ehricht, Konrad Sachse
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0033237
Abstract: Mycoplasmas comprise a conglomerate of pathogens and commensals occurring in humans and animals. The genus Mycoplasma alone contains more than 120 species at present, and new members are continuously being discovered. Therefore, it seems promising to use a single highly parallel detection assay rather than develop separate tests for each individual species. In this study, we have designed a DNA microarray carrying 70 oligonucleotide probes derived from the 23S rRNA gene and 86 probes from the tuf gene target regions. Following a PCR amplification and biotinylation step, hybridization on the array was shown to specifically identify 31 Mycoplasma spp., as well as 3 Acholeplasma spp. and 3 Ureaplasma spp. Members of the Mycoplasma mycoides cluster can be recognized at subgroup level. This procedure enables parallel detection of Mollicutes spp. occurring in humans, animals or cell culture, from mono- and multiple infections, in a single run. The main advantages of the microarray assay include ease of operation, rapidity, high information content, and affordability. The new test's analytical sensitivity is equivalent to that of real-time PCR and allows examination of field samples without the need for culture. When 60 field samples from ruminants and birds previously analyzed by denaturing-gradient gel electrophoresis (DGGE) were tested by the microarray assay both tests identified the same agent in 98.3% of the cases. Notably, microarray testing revealed an unexpectedly high proportion (35%) of multiple mycoplasma infections, i.e., substantially more than DGGE (15%). Two of the samples were found to contain four different Mycoplasma spp. This phenomenon deserves more attention, particularly its implications for epidemiology and treatment.
Testing the Evolutionary Sequence of High Mass Protostars with CARMA
S. Schnee,J. Carpenter
Physics , 2009, DOI: 10.1088/0004-637X/698/2/1456
Abstract: We present 1" resolution CARMA observations of the 3mm continuum and 95 GHz methanol masers toward 14 candidate high mass protostellar objects (HMPOs). Dust continuum emission is detected toward seven HMPOs, and methanol masers toward 5 sources. The 3mm continuum sources have diameters < 2x10^4 AU, masses between 21 and 1200 M_sun, and volume densities > 10^8 cm^-3. Most of the 3mm continuum sources are spatially coincident with compact HII regions and/or water masers, and are presumed to be formation sites of massive stars. A strong correlation exists between the presence of 3mm continuum emission, 22 GHz water masers, and 95 GHz methanol masers. However, no 3mm continuum emission is detected toward ultracompact HII regions lacking maser emission. These results are consistent with the hypothesis that 22 GHz water masers and methanol masers are signposts of an early phase in the evolution of an HMPO before an expanding HII region destroys the accretion disk.
Introduction to dark matter experiments
R. W. Schnee
Physics , 2011,
Abstract: This is a set of four lectures presented at the Theoretical Advanced Study Institute (TASI-09) in June 2009. I provide an introduction to experiments designed to detect WIMP dark matter directly, focusing on building intuitive understanding of the characteristics of potential WIMP signals and the experimental techniques. After deriving the characteristics of potential signals in direct-detection experiments for standard WIMP models, I summarize the general experimental methods shared by most direct-detection experiments and review the advantages, challenges, and status of such searches (as of late 2009). Experiments are already probing SUSY models, with best limits on the spin-independent coupling below 10^-7 pb.
Bosons in Disc-Shaped Traps: From 3D to 2D
K. Schnee,J. Yngvason
Mathematics , 2005,
Abstract: We present a mathematically rigorous analysis of the ground state of a dilute, interacting Bose gas in a three-dimensional trap that is strongly confining in one direction so that the system becomes effectively two-dimensional. The parameters involved are the particle number, $N\gg 1$, the two-dimensional extension, $\bar L$, of the gas cloud in the trap, the thickness, $h\ll \bar L$ of the trap, and the scattering length $a$ of the interaction potential. Our analysis starts from the full many-body Hamiltonian with an interaction potential that is assumed to be repulsive, radially symmetric and of short range, but otherwise arbitrary. In particular, hard cores are allowed. Under the premisses that the confining energy, $\sim 1/h^2$, is much larger than the internal energy per particle, and $a/h\to 0$, we prove that the system can be treated as a gas of two-dimensional bosons with scattering length $a_{\rm 2D}= h\exp(-(\hbox{\rm const.)}h/a)$. In the parameter region where $a/h\ll |\ln(\bar\rho h^2)|^{-1}$, with $\bar\rho\sim N/\bar L^2$ the mean density, the system is described by a two-dimensional Gross-Pitaevskii density functional with coupling parameter $\sim Na/h$. If $|\ln(\bar\rho h^2)|^{-1}\lesssim a/h$ the coupling parameter is $\sim N |\ln(\bar\rho h^2)|^{-1}$ and thus independent of $a$. In both cases Bose-Einstein condensation in the ground state holds, provided the coupling parameter stays bounded.
Calculating a confidence interval on the sum of binned leakage
Ian Ruchlin,Richard W. Schnee
Physics , 2011, DOI: 10.1016/j.nima.2011.11.031
Abstract: Calculating the expected number of misclassified outcomes is a standard problem of particular interest for rare-event searches. The Clopper-Pearson method allows calculation of classical confidence intervals on the amount of misclassification if data are all drawn from the same binomial probability distribution. However, data is often better described by breaking it up into several bins, each represented by a different binomial distribution. We describe and provide an algorithm for calculating a classical confidence interval on the expected total number of misclassified events from several bins, based on calibration data with the same probability of misclassification on a bin-by-bin basis. Our method avoids a computationally intensive multidimensional search by introducing a Lagrange multiplier and performing standard root finding. This method has only quadratic time complexity as the number of bins, and produces confidence intervals that are only slightly conservative.
Alzheimer's Disease and the Amyloid Cascade Hypothesis: A Critical Review
Christiane Reitz
International Journal of Alzheimer's Disease , 2012, DOI: 10.1155/2012/369808
Abstract: Since 1992, the amyloid cascade hypothesis has played the prominent role in explaining the etiology and pathogenesis of Alzheimer's disease (AD). It proposes that the deposition of β-amyloid (Aβ) is the initial pathological event in AD leading to the formation of senile plaques (SPs) and then to neurofibrillary tangles (NFTs), neuronal cell death, and ultimately dementia. While there is substantial evidence supporting the hypothesis, there are also limitations: (1) SP and NFT may develop independently, and (2) SPs and NFTs may be the products rather than the causes of neurodegeneration in AD. In addition, randomized clinical trials that tested drugs or antibodies targeting components of the amyloid pathway have been inconclusive. This paper provides a critical overview of the evidence for and against the amyloid cascade hypothesis in AD and provides suggestions for future directions. 1. Introduction Alzheimer’s disease (AD), which is characterized by progressive deterioration in cognition, function, and behavior, places a considerable burden on western societies. It is the sixth leading cause of all deaths and the fifth leading cause of death in persons aged ≥65 years. To date, an estimated 5.4 million Americans have AD, but due to the baby boom generation, the incidence in 2050 is expected to reach a million persons per year, resulting in a total estimated prevalence of 11 to 16 million affected persons. Since the first description of presenile dementia by Alois Alzheimer in 1907 [1], senile plaques (SPs) and neurofibrillary tangles (NFTs) are considered the key pathological hallmarks of AD [2]. The identification of β-amyloid (Aβ) in SPs [3] and genetic studies that identified mutations in the amyloid precursor protein (APP) [4], presenilin 1 (PSEN1), and presenilin 2 (PSEN2) genes [5, 6] leading to the accumulation of Aβ and early-onset familial dementia [4, 5, 7], resulted in the formulation of the “Amyloid Cascade Hypothesis” (ACH; Figure 1) [8, 9]. According to the ACH, the deposition of Aβ is the initial pathological trigger in the disease, which subsequently leads to the formation of NFTs, neuronal cell death and dementia. While there is considerable evidence supporting this hypothesis, there are observations that seem to be inconsistent. This paper summarizes the current evidence for and against the amyloid cascade in AD. Figure 1: Amyloid cascade hypothesis. 2. Amyloid Cascade Hypothesis As described above, two key observations resulted in the original formulation of the ACH (Figure 1). First, the detection of Aβ as a main constituent of the
Glandular areas associated with the male genitalia in Triatoma rubrofasciata (Triatominae, Reduviidae, Hemiptera) and other Reduviidae
Weirauch, Christiane;
Memórias do Instituto Oswaldo Cruz , 2003, DOI: 10.1590/S0074-02762003000600011
Abstract: in this paper, glandular areas associated with the phallus in triatoma rubrofasciata are described and illustrated for the first time. the glandular areas lie in the membrane surrounding the articulatory apparatus. in order to unambiguously define the locality of the respective glandular areas, some features of the pygophore-phallus connection are redescribed. a possible functional context of the gland secretions is discussed. a preliminary study of several other reduviidae implies that the described glandular areas occur in a wider range of taxa in this group.
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