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Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The authors have previously proposed a novel refractive index two-dimensional sensing technique named "parallel scan spectral surface plasmon resonance imaging". In the technique, with a line-shaped light illumination, an image acquired with CCD detector could provide both SPR wavelength information and one-dimensional spatial distribution, and then provide one-dimensional distribution of refractive index with further calculation. Thus, two-dimensional distribution of refractive index of the entire sensing area can be obtained with one-dimensional optical line parallel scan. The technique offers advantages of both high sensitivity and high throughput, and could have potential applications in microarray analysis. In the present paper, the authors improve the data processing methods of the technique. The authors use the refractive index of air as a reference to get over the problem of precision of the incident angle. The authors also sense a manually dotted Legionella pneumophila mip DNA probe array with this technique and prove the feasibility of sensing microarrays by this highly sensitive and label-free technique. The relation between the equivalent refractive indices and the concentrations of the dotted Legionella pneumophila mip DNA probes is obtained, which has important reference value for further study.
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PMID:[A novel spectral surface plasmon resonance 2-D sensing technique and its applications in DNA microarrays]. 2030 4

Significant research efforts are continually being directed towards the development of sensitive and accurate surface plasmon resonance biosensors for sequence specific DNA detection. These sensors hold great potential for applications in healthcare and diagnostics. However, the performance of these sensors in practical usage scenarios is often limited due to interference from the sample matrix. This work shows how the co-immobilization of glycol(PEG) diluents or 'back filling' of the DNA sensing layer can successfully address these problems. A novel SPR based melting assay is used for the analysis of a synthetic oligomer target as well as PCR amplified genomic DNA extracted from Legionella pneumophila. The benefits of sensing layer back filling on the assay performance are first demonstrated through melting analysis of the oligomer target and it is shown how back filling enables accurate discrimination of Legionella pneumophila serogroups directly from the PCR reaction product with complete suppression of sensor fouling.
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PMID:Enabling fiber optic serotyping of pathogenic bacteria through improved anti-fouling functional surfaces. 2260 31

A home-built fiber optic surface plasmon resonance platform (FO-SPR) was applied to directly screen PCR amplified DNA for mutations. The FO-SPR sensor was used for real-time monitoring of DNA duplex melting during high resolution temperature cycling. The signal of the DNA melting was enhanced by means of gold nanoparticle labels. This FO-SPR genetic assay allowed for detection of single-point mutations (SNP) in less than 20 min. The concept was demonstrated for the analysis of 9 different serogroups of the bacterium Legionella pneumophila, a common human pathogen responsible for atypical pneumonia. FO-SPR allowed us to detect genetic mutations inhibiting PCR, which could lead to amplification bias when molecular diagnostics are applied for L. pneumophila detection. All serogroups were found to display unique melting temperatures, indicating that mutations have accumulated in the target sequence. In a next step, clinical samples of L. pneumophila were analyzed using the FO-SPR sensor. This technology was proven to be reliable for the detection of mutations for those samples that previously displayed ambiguous qPCR quantification results. When these results were benchmarked, FO-SPR results were found to be consistent with Sanger sequencing but not with fluorescence based DNA melting. The presented results convincingly advocate the advantages of FO-SPR as a high resolution and fast genetic screening tool that can compete with the current standard techniques for SNP detection.
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PMID:Spherical nucleic acid enhanced FO-SPR DNA melting for detection of mutations in Legionella pneumophila. 2328 39

Due to its well-characterized and highly conserved structure, as well as its relative abundance in metabolically active cells, bacterial 16S rRNA sequence plays an important role in microbial identification. In this work, a biosensing strategy has been developed for simultaneous detection of 16S rRNA analytes of three pathogenic bacterial strains: Legionella pneumophila, Pseudomonas aeruginosa, and Salmonella typhimurium. Surface plasmon resonance imaging (SPRi) was used as a detection technique coupled with DNA probe sandwich assemblies and gold nanoparticles (GNPs) for signal amplification. The targets 16S rRNA were selectively captured at the interface of the biosensor by surface-bound DNA probes through a hybridization process. GNP-grafted DNA detection probes were then introduced and were hybridized with a defined 16S rRNA region on the long DNA-RNA sandwich assemblies, resulting in a significant increase of the SPR signal. The results demonstrated the successful implementation of this strategy for detecting 16S rRNA sequences in total RNA mixed samples extracted from the three pathogenic strains at a concentration down to 10 pg mL-1 with a large dynamic range of 0.01-100 ng mL-1 and high selectivity. Since no particular optimization of the probe design was applied, this method should be relatively easy to adapt for quantification of a wide range of bacteria in various liquids.
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PMID:Selective and High Dynamic Range Assay Format for Multiplex Detection of Pathogenic Pseudomonas aeruginosa, Salmonella typhimurium, and Legionella pneumophila RNAs Using Surface Plasmon Resonance Imaging. 2868 93