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Limited Resolution (limited + resolution)
Selected AbstractsEstimating the spatiotemporal pattern of volumetric growth rate from fate maps in chick limb developmentDEVELOPMENTAL DYNAMICS, Issue 2 2009Yoshihiro Morishita Abstract Morphogenesis is achieved through volumetric growth of tissue at a rate varying over space and time. The volumetric growth rate of each piece of tissue reflects the behaviors of constituent cells such as cell proliferation and death. Hence, clarifying its spatiotemporal pattern accurately is a key to bridge between cell behaviors and organ morphogenesis. We here propose a new method to estimate the spatiotemporal pattern of volumetric growth rate from fate map data with limited resolution on space and time by using a mathematical model. We apply the method to chick wing data along the proximodistal axis, and find that the volumetric growth pattern is biphasic: it is spatially uniform in earlier stages (until stage 23), but in later stages the volumetric growth occurs approximately 4.5 times as fast as in the distal region (within approximately 100 ,m from the limb tip) than in the proximal region. Developmental Dynamics 238:415,422, 2009. © 2009 Wiley-Liss, Inc. [source] Restriction analysis of PCR amplified nrDNA regions revealed intraspecific variation within populations of Fusarium culmorumFEMS MICROBIOLOGY LETTERS, Issue 2 2002Prashant K Mishra Abstract Seventy-five isolates of Fusarium culmorum with diverse geographical origin and host were analyzed using restriction digestion of polymerase chain reaction amplified nuclear ribosomal DNA intergenic spacer (IGS) and 28S gene regions. The 28S gene was conserved and has produced identical restriction patterns, however, the IGS region was substantially variable. The isolates were divided into 29 unique IGS haplotypes. There was limited resolution between clustering of isolates and their origin and/or host. The variability was distributed largely equally at both macro- and micro-geographical scale. The phylogeographic distribution pattern suggests a seed-borne dispersal of F. culmorum. [source] Microbeam small-angle scattering experiments and their combination with microdiffractionJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3-1 2000C. Riekel The brilliance of undulator X-ray sources can be used to develop microfocusing optics for wide-angle (WAXS) and small-angle (SAXS) X-ray scattering. At the ESRF microfocus beamline, a beam size of 10 ,m is obtained by a pinhole collimating system coupled to a double focusing mirror. This allows resolving the first order of collagen (67 nm). Glass capillary optics provides a beam size close to one micron, however, with a more limited resolution. A high-resolution CCD detector allows combined SAXS/WAXS experiments for one detector setting. [source] How the CO in myoglobin acquired its bend: lessons in interpretation of crystallographic dataACTA CRYSTALLOGRAPHICA SECTION D, Issue 5 2001Boguslaw Stec Contrary to the expectation of chemists, the first X-ray structures of carbon monoxide bound to myoglobin (Mb) showed a highly distorted Fe,C,O bond system. These results appeared to support the idea of a largely steric mechanism for discrimination by the protein against CO binding, a lethal act for the protein in terms of its physiological function. The most recent independently determined high-resolution structures of Mb,CO have allowed the 25,year old controversy concerning the mode of CO binding to be resolved. The CO is now seen to bind in a roughly linear fashion without substantial bending, consistent with chemical expectations and spectroscopic measurements. Access to deposited diffraction data prompted a reevaluation of the sources of the original misinterpretation. A series of careful refinements of models against the data at high (1.1,Å) and modest resolutions (1.5,Å) have been performed in anisotropic versus isotropic modes. The results suggest that the original artifact was a result of lower quality crystals combined with anisotropic motion and limited resolution of the diffraction data sets. This retrospective analysis should serve as a caution for all researchers using structural tools to draw far-reaching biochemical conclusions. [source] Morphological and Molecular Evidence of Arbuscular Mycorrhizal Fungal Associations in Costa Rican Epiphytic Bromeliads,BIOTROPICA, Issue 2 2005Annette R. Rowe ABSTRACT Arbuscular mycorrhizal fungi influence the growth, morphology, and fitness of a variety of plant species, but little is known of the arbuscular mycorrhizal (AM) fungal associations of plant species in forest canopies. Plant species' associations with AM fungi are most often elucidated by examining the roots for fungal structures; however, morphological data may provide a limited resolution on a plant's mycorrhizal status. We combined a traditional staining technique with a molecular marker (the 18S ribosomal gene) to determine whether or not a variety of epiphytic bromeliads form arbuscular mycorrhizal fungal associations. Using these methods we show that the epiphytic bromeliad Vriesea werkleana forms arbuscular mycorrhizal fungal associations with members of the genus Glomus. AM fungal sequences of this plant species formed three distinct clades nested within a larger Glomus clade; two of the clades did not group with any previously sequenced lineage of Glomus. Novel clades may represent novel species. Although Vriesea werkleana is associated with multiple AM fungal species, each individual plant is colonized by a single lineage. The combination of morphological and molecular methods provides a practical approach to the characterization of the mycorrhizal status of epiphytic bromeliads, and perhaps other tropical epiphytes. [source] Comparative genomic hybridization (CGH)-arrays pave the way for identification of novel cancer-related genesCANCER SCIENCE, Issue 7 2004Johji Inazawa Comparative genomic hybridization (CGH) has already made a significant impact on cancer Cytogenetics. However, CGH to metaphase chromosomes can provide only limited resolution at the 5,10 Mb level. To circumvent this limitation, array-based CGH has been devised. Since spotted DMAs in a CGH-array contain sequence information directly connected with the genome database, we can easily note particular biological aspects of genes that lie within regions involved in copy-number aberrations. High-density, sub-megabase arrays can reveal nonrandom chromosome copy-number aberrations responsible for neoplastic transformation that have been masked under complex karyotypes in epithelial solid tumors. High-density CGH-array therefore paves the way for identification of disease-related genetic aberrations that have not yet been detected by existing technologies, and array-based CGH technology should soon be practical for diagnosis of cancer or genetic diseases in the clinical setting. [source] Alterations of intraretinal layers in acute central serous chorioretinopathyACTA OPHTHALMOLOGICA, Issue 5 2009Christian Ahlers Abstract. Purpose:, Optical coherence tomography (OCT) is restricted by its low scanning speed and limited resolution. High-definition raster-scanning OCT (HD-OCT) was used to evaluate changes in retinal microstructure in patients with acute central serous chorioretinopathy (CSCR) and to find new morphological features. Methods:, Eighteen patients with subretinal fluid accumulation caused by acute CSCR were imaged in a cross-sectional study design. High-speed frequency-domain HD-OCT was used to image an area of 6 × 6 mm in the macular retina. Three-dimensional analyses were performed using en-face imaging and section analysis of single HD-OCT scans. Results:, Detailed information about fluid accumulation can be obtained in all compartments. Discrete changes in reflectivity are visualized within the outer nuclear or plexiform layers in > 90% of patients. Subretinal fluid appears as a dome-shaped pool of fluid and is not associated with a loss of photoreceptor layer integrity. Deposits are demarcated beneath the outer cone segments. Multiple small pigment epithelial detachments are present in > 60% of patients. Conclusions:, High-definition OCT provides extensive information regarding precise topographic and layer-specific localization of discrete morphological changes. Along with well-known changes in the retinal microstructure, hyper-reflectivity can be imaged in the outer nuclear or plexiform layers and may represent intraretinal changes indicating the presence of subretinal pathologies or retinal maladjustment caused by the underlying pathology. [source] | ||||||||||||||||