636 research outputs found

    Charakterisierung der Resistenz deutscher Weizensorten gegenüber Weizenflugbrand (Ustilago tritici)

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    Die Resistenzzüchtung gegenüber Weizenflugbrand (Ustilago tritici) hat in den letzten Jahren aufgrund der Ausdehnung des ökologischen Landbaus, der eine Bekämpfung mittels chemischer Saatgutbeizung nicht zulässt, zunehmend an Bedeutung gewonnen. Ziel eines im Rahmen des „Bundesprogramm Ökologischer Landbau“ geförderten Projektes war es daher, Resistenzen im deutschen Weizensortiment, als Basis für eine direkte Nutzung dieser Sorten im ökologischen Anbau bzw. als Ausgangspunkt für eine gezielte Resistenzzüchtung, zu identifizieren

    C. elegans mutant identification with a one-step whole-genome-sequencing and SNP mapping strategy.

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    Whole-genome sequencing (WGS) is becoming a fast and cost-effective method to pinpoint molecular lesions in mutagenized genetic model systems, such as Caenorhabditis elegans. As mutagenized strains contain a significant mutational load, it is often still necessary to map mutations to a chromosomal interval to elucidate which of the WGS-identified sequence variants is the phenotype-causing one. We describe here our experience in setting up and testing a simple strategy that incorporates a rapid SNP-based mapping step into the WGS procedure. In this strategy, a mutant retrieved from a genetic screen is crossed with a polymorphic C. elegans strain, individual F2 progeny from this cross is selected for the mutant phenotype, the progeny of these F2 animals are pooled and then whole-genome-sequenced. The density of polymorphic SNP markers is decreased in the region of the phenotype-causing sequence variant and therefore enables its identification in the WGS data. As a proof of principle, we use this strategy to identify the molecular lesion in a mutant strain that produces an excess of dopaminergic neurons. We find that the molecular lesion resides in the Pax-6/Eyeless ortholog vab-3. The strategy described here will further reduce the time between mutant isolation and identification of the molecular lesion

    Appendix to "Approximating perpetuities"

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    An algorithm for perfect simulation from the unique solution of the distributional fixed point equation Y=dUY+U(1U)Y=_d UY + U(1-U) is constructed, where YY and UU are independent and UU is uniformly distributed on [0,1][0,1]. This distribution comes up as a limit distribution in the probabilistic analysis of the Quickselect algorithm. Our simulation algorithm is based on coupling from the past with a multigamma coupler. It has four lines of code

    The effects of orange Citrus reticulata extracts towards vertigoand dizziness of EEGAFI Students

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    Dizziness and imbalance are common conditions affecting people of all ages in different walks of life, particularly the students. This study was performed to describe and determine the potential effect of orange peel on dizziness or vertigo towards the students in EEGAFI. The researchers will require a field to conduct a sort of semi- experiment but not performed in clinical sphere of producing the finished extract of Citrus reticulata. The researchers have chosen the students of ECT Excellencia Global Academy Foundation, Inc. (EEGAFI) in a targeted sample of the population. Since the location where this survey was held provided “hybrid blended learning,” the research team also used notes and questionnaires via Google Forms, and some respondents found it convenient to respond in their own homes, making it simple for them to assume responsibility as respondents in this research study. In total, 11 students from various strands of the EEGAFI in grades 11 and 12 who had previously experienced vertigo or dizziness participated in this study. There were 11 STEM a (bravery), 11 STEM B (perseverance), and 12 UNITY (Graph 1). The result of the study found out that Citrus reticulata had a statistically significant effect on the study participants’ dizziness and vertigo experiences. It is imperative to maintain the physical fitness of EEGAFI students. The results suggest that dizziness and vertigo have a real impact on a student’s ability to develop and improve their activities and academic performance. Students who experience the pain and distractions of dizziness will likely experience negative emotions, burdens, and tension that cause terrible results in class. Due to their inability to properly comprehend their ideas and original works, they will probably also get a lesser grade

    Neural development features: Spatio-temporal development of the Caenorhabditis elegans neuronal network

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    The nematode Caenorhabditis elegans, with information on neural connectivity, three-dimensional position and cell linage provides a unique system for understanding the development of neural networks. Although C. elegans has been widely studied in the past, we present the first statistical study from a developmental perspective, with findings that raise interesting suggestions on the establishment of long-distance connections and network hubs. Here, we analyze the neuro-development for temporal and spatial features, using birth times of neurons and their three-dimensional positions. Comparisons of growth in C. elegans with random spatial network growth highlight two findings relevant to neural network development. First, most neurons which are linked by long-distance connections are born around the same time and early on, suggesting the possibility of early contact or interaction between connected neurons during development. Second, early-born neurons are more highly connected (tendency to form hubs) than later born neurons. This indicates that the longer time frame available to them might underlie high connectivity. Both outcomes are not observed for random connection formation. The study finds that around one-third of electrically coupled long-range connections are late forming, raising the question of what mechanisms are involved in ensuring their accuracy, particularly in light of the extremely invariant connectivity observed in C. elegans. In conclusion, the sequence of neural network development highlights the possibility of early contact or interaction in securing long-distance and high-degree connectivity

    Nemo: a computational tool for analyzing nematode locomotion

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    The nematode Caenorhabditis elegans responds to an impressive range of chemical, mechanical and thermal stimuli and is extensively used to investigate the molecular mechanisms that mediate chemosensation, mechanotransduction and thermosensation. The main behavioral output of these responses is manifested as alterations in animal locomotion. Monitoring and examination of such alterations requires tools to capture and quantify features of nematode movement. In this paper, we introduce Nemo (nematode movement), a computationally efficient and robust two-dimensional object tracking algorithm for automated detection and analysis of C. elegans locomotion. This algorithm enables precise measurement and feature extraction of nematode movement components. In addition, we develop a Graphical User Interface designed to facilitate processing and interpretation of movement data. While, in this study, we focus on the simple sinusoidal locomotion of C. elegans, our approach can be readily adapted to handle complicated locomotory behaviour patterns by including additional movement characteristics and parameters subject to quantification. Our software tool offers the capacity to extract, analyze and measure nematode locomotion features by processing simple video files. By allowing precise and quantitative assessment of behavioral traits, this tool will assist the genetic dissection and elucidation of the molecular mechanisms underlying specific behavioral responses.Comment: 12 pages, 2 figures. accepted by BMC Neuroscience 2007, 8:8

    Contribution of the cyclic nucleotide gated channel subunit, CNG-3, to olfactory plasticity in Caenorhabditis elegans.

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    In Caenorhabditis elegans, the AWC neurons are thought to deploy a cGMP signaling cascade in the detection of and response to AWC sensed odors. Prolonged exposure to an AWC sensed odor in the absence of food leads to reversible decreases in the animal's attraction to that odor. This adaptation exhibits two stages referred to as short-term and long-term adaptation. Previously, the protein kinase G (PKG), EGL-4/PKG-1, was shown necessary for both stages of adaptation and phosphorylation of its target, the beta-type cyclic nucleotide gated (CNG) channel subunit, TAX-2, was implicated in the short term stage. Here we uncover a novel role for the CNG channel subunit, CNG-3, in short term adaptation. We demonstrate that CNG-3 is required in the AWC for adaptation to short (thirty minute) exposures of odor, and contains a candidate PKG phosphorylation site required to tune odor sensitivity. We also provide in vivo data suggesting that CNG-3 forms a complex with both TAX-2 and TAX-4 CNG channel subunits in AWC. Finally, we examine the physiology of different CNG channel subunit combinations

    A Toolkit and Robust Pipeline for the Generation of Fosmid-Based Reporter Genes in C. elegans

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    Engineering fluorescent proteins into large genomic clones, contained within BACs or fosmid vectors, is a tool to visualize and study spatiotemporal gene expression patterns in transgenic animals. Because these reporters cover large genomic regions, they most likely capture all cis-regulatory information and can therefore be expected to recapitulate all aspects of endogenous gene expression. Inserting tags at the target gene locus contained within genomic clones by homologous recombination (“recombineering”) represents the most straightforward method to generate these reporters. In this methodology paper, we describe a simple and robust pipeline for recombineering of fosmids, which we apply to generate reporter constructs in the nematode C. elegans, whose genome is almost entirely covered in an available fosmid library. We have generated a toolkit that allows for insertion of fluorescent proteins (GFP, YFP, CFP, VENUS, mCherry) and affinity tags at specific target sites within fosmid clones in a virtually seamless manner. Our new pipeline is less complex and, in our hands, works more robustly than previously described recombineering strategies to generate reporter fusions for C. elegans expression studies. Furthermore, our toolkit provides a novel recombineering cassette which inserts a SL2-spliced intercistronic region between the gene of interest and the fluorescent protein, thus creating a reporter controlled by all 5′ and 3′ cis-acting regulatory elements of the examined gene without the direct translational fusion between the two. With this configuration, the onset of expression and tissue specificity of secreted, sub-cellular compartmentalized or short-lived gene products can be easily detected. We describe other applications of fosmid recombineering as well. The simplicity, speed and robustness of the recombineering pipeline described here should prompt the routine use of this strategy for expression studies in C. elegans
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