Publications by authors named "Bruijn F"

Biomedical imaging is unequivocally dependent on the ability to reconstruct interpretable and high-quality images from acquired sensor data. This reconstruction process is pivotal across many applications, spanning from magnetic resonance imaging to ultrasound imaging. While advanced data-adaptive reconstruction methods can recover much higher image quality than traditional approaches, their implementation often poses a high computational burden.

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The Rhizobiaceae are a bacterial family of enormous agricultural importance due to the ability of its members to fix atmospheric nitrogen in an intimate relationship with plants. Their survival as naturally occurring soil bacteria in agricultural soils as well as popular seed inocula is affected directly by drought and salinity. Survival after desiccation in the presence of NaCl is enabled by underlying genetic mechanisms in the model organism Sinorhizobium meliloti 1021.

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This paper describes a stand-alone sensor package and algorithms for aiding the assessment by an occupational therapist whether a person has the capacity to safely and effectively operate a powered mobility device such as a walking aid or a wheelchair. The sensor package employed consists of a laser range finder, an RGB camera and an inertial measurement unit that can be attached to any mobility device with minimal modifications. Algorithms for capturing the data received by the sensor package and for generating the map of the environment as well as the trajectory of the mobility device have been developed.

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Sinorhizobium meliloti is a microorganism commercially used in the production of e.g. Medicago sativa seed inocula.

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The temperature increase of bulk acoustic wave filters at high RF power levels has been investigated. Self-heating due to power dissipation in the filter leads to a nonuniform frequency shift of the insertion loss. At the right filter skirt, self-heating is amplified by the negative temperature coefficient of frequency.

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ABSTRACT The genomic DNA fingerprinting technique known as repetitive-sequence-based polymerase chain reaction (rep-PCR) was evaluated as a tool to differentiate subspecies of Clavibacter michiganensis, with special emphasis on C. michiganensis subsp. michiganensis, the pathogen responsible for bacterial canker of tomato.

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ABSTRACT Four hundred thirty-three xanthomonad strains isolated from tomato or pepper plants from 32 different fields in four Caribbean and Central American countries were screened for the ability to hydrolyze starch and sodium polypectate and for resistance to copper and streptomycin. Of these, 95 representative strains were further characterized by various phnetic tests, and 63 of these strains were then analyzed by genomic fingerprinting. Most of the strains (>90%) were tolerant to copper.

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ABSTRACT In order to confirm and refine the current classification scheme of Xanthomonas translucens and to identify novel strains from ornamental asparagus, a collection of field and reference strains was analyzed. Rep-polymerase chain reaction (PCR) genomic fingerprint profiles were generated from 33 isolates pathogenic to asparagus as well as 61 X. trans-lucens reference strains pathogenic to cereals and grasses.

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ABSTRACT A comprehensive classification framework was developed that refines the current Xanthomonas classification scheme and provides a detailed assessment of Xanthomonas diversity at the species, subspecies, pathovar, and subpathovar levels. Polymerase chain reaction (PCR) using primers targeting the conserved repetitive sequences BOX, enterobacterial repetitive intergenic consensus (ERIC), and repetitive extragenic palindromic (REP) (rep-PCR) was used to generate genomic fingerprints of 339 Xanthomonas strains comprising 80 pathovars, 20 DNA homology groups, and a Stenotrophomonas maltophilia reference strain. Computer-assisted pattern analysis of the rep-PCR profiles permitted the clustering of strains into distinct groups, which correspond directly to the 20 DNA-DNA homology groups(genospecies) previously identified.

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Falling is a common problem among elderly people and has many negative consequences. In the Netherlands, there is a need for effective fall prevention interventions aimed at elderly persons with an increased risk of falling. For this reason, we adapted a successful British fall prevention program comprising a medical occupational therapy assessment to the Dutch health care setting.

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Whole-genome transcriptional profiling was used to identify genes in Sinorhizobium meliloti 1021 that are differentially expressed during exposure to elevated concentrations of cadmium and zinc. Mutant strains with insertions in metal-regulated genes and in genes encoding putative metal efflux pumps were analyzed for their metal sensitivities, revealing a crucial role for the SMc04128-encoded P-type ATPase in the defense of S. meliloti against cadmium and zinc stress.

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A previously generated collection of 11 Tn5-luxAB insertion mutants of Sinorhizobium meliloti harbouring lux reporter gene fusions induced under microaerobic (1% O2) conditions was further characterized and mapped on the sequenced S. meliloti genome. One highly induced gene fusion from this collection (loe-7) was found to be located in the intergenic region between sma1292, encoding a putative protease/collagenase, and a gene of unknown function (sma1294).

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Aims: To identify physical and physiological conditions that affect the survival of Sinorhizobium meliloti USDA 1021 during desiccation.

Methods And Results: An assay was developed to study desiccation response of S. meliloti USDA 1021 over a range of environmental conditions.

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Sinorhizobium meliloti is an alpha-proteobacterium that alternates between a free-living phase in bulk soil or in the rhizosphere of plants and a symbiotic phase within the host plant cells, where the bacteria ultimately differentiate into nitrogen-fixing organelle-like cells, called bacteroids. As a step toward understanding the physiology of S. meliloti in its free-living and symbiotic forms and the transition between the two, gene expression profiles were determined under two sets of biological conditions: growth under oxic versus microoxic conditions, and in free-living versus symbiotic state.

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In order to prepare for whole-genome expression analysis in Sinorhizobium meliloti, pilot DNA macroarrays were designed for 34 genes of known regulation. The experimental parameters assessed were the length of the PCR products, the influence of a tag at the 5' end of the primers, and the method of RNA labeling. Variance and principal-component analysis showed that the most important nonbiological parameter was the labeling method.

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In legumes, root nodule organogenesis is activated in response to morphogenic lipochitin oligosaccharides that are synthesized by bacteria, commonly known as rhizobia. Successful symbiotic interaction results in the formation of highly specialized organs called root nodules, which provide a unique environment for symbiotic nitrogen fixation. In wild-type plants the number of nodules is regulated by a signalling mechanism integrating environmental and developmental cues to arrest most rhizobial infections within the susceptible zone of the root.

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The Mesorhizobium loti strain R7A symbiosis island is a 502-kb chromosomally integrated element which transfers to nonsymbiotic mesorhizobia in the environment, converting them to Lotus symbionts. It integrates into a phenylalanine tRNA gene in a process mediated by a P4-type integrase encoded at the left end of the element. We have determined the nucleotide sequence of the island and compared its deduced genetic complement with that reported for the 611-kb putative symbiosis island of M.

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An 8551-bp plasmid, pFQ11, from Frankia alni strain CpI1 was sequenced. Its sequence was found to be very similar to that presented for pFQ31 from strain ArI3. Six potential protein-encoding open reading frames (ORFs) were identified, and transcriptional activity was shown within four of those regions of the plasmid by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis.

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The advent of molecular biology in general and the polymerase chain reaction in particular have greatly facilitated genomic analyses of microorganisms, provide enhanced capability to characterize and classify strains, and facilitate research to assess the genetic diversity of populations. The diversity of large populations can be assessed in a relatively efficient manner using rep-PCR-, AFLP-, and AP-PCR/RAPD-based genomic fingerprinting methods, especially when combined with computer-assisted pattern analysis. Genetic diversity maps provide a framework to understand the taxonomy, population structure, and dynamics of phytobacteria and provide a high-resolution framework to devise sensitive, specific, and rapid methods for pathogen detection, plant disease diagnosis, as well as management of disease risk.

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Eleven Sinorhizobium meliloti 1021 loci whose expression was induced under low oxygen concentrations were identified in a collection of 5,000 strains carrying Tn5-1063 (luxAB) transcriptional reporter gene fusions. The 11 Tn5-1063-tagged loci were cloned and characterized. The dependence of the expression of the tagged loci on the FixL/FixJ oxygen-sensing two-component regulatory system was examined.

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Phosphatidylinositol transfer proteins (PITPs) modulate signal transduction pathways and membrane-trafficking functions in eukaryotes. Here, we describe the characterization of a gene family from Lotus japonicus that encodes a novel class of plant PITP-like proteins (LjPLPs) and that is regulated in an unusual nodule-specific manner. Members of this gene family were identified based on their nucleotide sequence homology with a previously described cDNA, LjNOD16, which encodes the L.

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The regulation of the nutrient-deprivation-induced Sinorhizobium meliloti homogentisate dioxygenase (hmgA) gene, involved in tyrosine degradation, was examined. hmgA expression was found to be independent of the canonical nitrogen regulation (ntr) system. To identify regulators of hmgA, secondary mutagenesis of an S.

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A nutrient deprivation-induced locus in Sinorhizobium meliloti strain 1021 was identified by use of a Tn5-luxAB reporter gene transposon. The tagged locus is comprised of two open reading frames (ORFs) designated ndiA and ndiB for nutrient deprivation-induced genes A and B. Comparison of the deduced amino acid sequences of both ndiA and ndiB to the protein databases failed to reveal similarity to any known genes.

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Rhizobium tropici strain CIAT899 displays a high intrinsic thermal tolerance, and had been used in this work to study the molecular basis of bacterial responses to high temperature. We generated a collection of R. tropici CIAT899 mutants affected in thermal tolerance using TnS-luxAB mutagenesis and described the characterization of a mutant strain, CIAT899-10T, that fails to grow under conditions of high temperature.

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