Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

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

To determine the infection source of a sporadic Legionella pneumonia case associated with a hot spring bath, we used five molecular methods, including repetitive element polymerase chain reaction (rep-PCR), arbitrarily primed PCR (AP-PCR), ribotyping, restriction endonuclease analysis (REA), and macrorestriction endonuclease analysis (MREA) by pulsed-field gel electrophoresis. L. pneumophila serogroup (SG) 3 strain EY 3702, isolated from an intratracheal specimen of a 71-year-old Japanese female who developed pneumonia after nearly drowning in a hot spring spa bath, produced rep-PCR and AP-PCR fingerprints identical to those of L. pneumophila SG 3 strains EY 3768 and EY 3769 isolated from the bath water. Four epidemiologically unrelated L. pneumophila SG 3 strains showed different rep-PCR or AP-PCR fingerprints from those of the three EY strains (EY 3702, 3768, and 3769). The three EY strains were also genotypically indistinguishable by ribotyping with EcoRI and PstI, by REA with EcoRI or HindIII, and by MREA with NotI. Based on these results, we identified the bath water of the hot spring spa as the source of infection of this patient, even though the viable number of the organisms in the bath water was low (3 CFU/100 ml) when determined 27 days after her nearly drowning.
...
PMID:Molecular determination of infection source of a sporadic Legionella pneumonia case associated with a hot spring bath. 913 Feb 30

Amphizoic small amoebic protozoa are capable of existing both in 'free-living' and in 'parasitic' form depending on the actual conditions. Two genera (Naegleria and Acanthamoeba) have become recognised as opportunist human parasites. Since the first description in 1965 of a lethal case of primary amoebic meningoencephalitis (PAM) caused by Naegleria, many more (mostly lethal) cases have been reported, while granulomatous amoebic encephalitis (GAE), as well as eye (keratinitis, conjunctivitis, etc.), ear, nose, skin and internal organ infections caused by Acanthamoeba have also occurred in rapidly increasing numbers. Both pathogenic and non-pathogenic species of Naegleria and Acanthamoeba are found worldwide in water, soil and dust, where they provide a potential source of infection. Successful differential diagnosis and appropriate (specific) therapy depends on precise laboratory identification of the 'free-living' amoebae. In most cases, isolation from the environment can be achieved, but identification and differentiation of the pathogenic and non-pathogenic strains is not easy. The methods presently available do not fulfil completely the requirements for specificity, sensitivity and reliability. Morphological criteria are inadequate, while thermophilic character, pH dependency and even virulence in infected mice, are not unambiguous features of pathogenicity of the different strains. More promising are molecular methods, such as restriction endonuclease digestion of whole-cell DNA or mitochondrial DNA, as well as iso-enzyme profile analysis after iso-electric focusing and staining for acid phosphatase and propionyl esterase activity. Use of appropriate monoclonal antibodies has also yielded promising results in the differentiation of human pathogenic and non-pathogenic strains. However, quicker, simpler, more specific and reliable methods are still highly desirable. The significance of endosymbiosis (especially with Legionella strains) is not well understood. The results of a systematic survey in Hungary for the isolation and identification of 'free-living' amoebae, including an investigation of the Hungarian amoebic fauna, the isolation of possibly pathogenic Naegleria strains and of some Acanthamoeba strains from eye diseases, as well as the finding of a case of endosymbiosis, are also reported here.
...
PMID:Isolation, identification and increasing importance of 'free-living' amoebae causing human disease. 978 20

A panel of 131 well-characterised Legionella pneumophila serogroup 1 strains, previously used to evaluate a restriction fragment-length polymorphisms (RFLP) typing scheme, was examined by pulsed-field gel electrophoresis (PFGE) with the restriction endonuclease SfiI. The data obtained show that PFGE with SfiI is a highly discriminatory method yielding an index of discrimination (IOD) of 0.992 and 0.975, with 100% and 90% similarity thresholds respectively, compared with an IOD of 0.909 for the RFLP typing method. Reproducibility of PFGE profiles within gels was excellent and it was possible to compare the profiles visually. However, the reproducibility of the technique between gels was poor and visual comparison of the patterns was extremely difficult. Computer-aided analysis assisted the assessment of inter-gel reproducibility. Of 11 duplicates examined only four pairs showed 100% similarity, although 9 of 11 showed > or =90% similarity. In an attempt to determine if the PFGE banding patterns were sufficiently unambiguous to allow the method to be used as a definitive typing method, 20 coded strains were examined. At a 90% similarity level, 16 of these were placed in the correct PFGE type and four were not allocated to a type. Partial digestion of DNA by SfiI was noted despite careful control of DNA and enzyme concentrations, suggesting that an alternative enzyme might give more reproducible results.
...
PMID:Molecular typing of Legionella pneumophila serogroup 1 by pulsed-field gel electrophoresis with SfiI and comparison of this method with restriction fragment-length polymorphism analysis. 1033 94

OBJECTIVES: To compare genotypic methods for epidemiologic typing of Legionella pneumophila serogroup (sg) 1, in order to determine the best available method within Europe for implementation and standardization by members of the European Working Group on Legionella Infections. METHODS: Coded isolates (114) of L. pneumophila sg 1 comprising one epidemiologically 'unrelated' (79) and one 'related' panel of isolates (35) were sent to 12 laboratories in 11 European countries. Analysis was undertaken in each laboratory using one or more of the following methods: ribotyping, restriction fragment length polymorphism analysis, restriction endonuclease analysis, pulsed-field gel electrophoresis (PFGE), PCR using arbitrary/repeat sequence primers (AP-, AP/rep-PCR), and amplified fragment length polymorphism (AFLP) analysis. Results were analyzed visually or using gel analysis software. Each method was assessed for its: index of discrimination (D), epidemiologic concordance (E), speed of application and ease of use. In addition, phenotypic analysis was performed in two laboratories using monoclonal antibodies (mAbs). RESULTS: The D of each of the genotypic methods ranged from 0.840 for ribotyping to 0.990 for PFGE using Sfil: E ranged from 0.06 for AP- and AP/rep-PCR to 1.00 for ribotyping using Pstl/EcoRI and AFLP: in general, E was inversely related to D. Although offering only limited discrimination (D=0.838), mAb typing was both rapid and highly epidemiologically concordant (E=1.00). CONCLUSIONS: Two methods, PFGE using Sfil and AFLP, were selected for further study. AFLP is rapid and highly epidemiologically concordant (E=1.00), but is not highly discriminatory. This method will be developed as a rapid screening tool. PFGE using Sfil is highly discriminatory but, in the present study, yielded low values of E (0.12-0.71). Attempts will be made to rigorously standardize this method for use as the reference method. Primary screening of isolates by mAb subgrouping is recommended.
...
PMID:A multicenter evaluation of genotypic methods for the epidemiologic typing of Legionella pneumophila serogroup 1: results of a pan-European study. 1185 90

There are currently more than 40 species of Legionella and the identification of most of them by standard methods is often technically difficult. The aim of this study was to use a ribotyping method with endonuclease HindIII and a probe consisting of a set of five oligonucleotides (referred to as OligoMix5). A total of 123 strains, including 78 type or reference strains corresponding to 44 species, eight clinical and 37 environmental isolates were tested. The usefulness of the method was demonstrated for the identification at the species level of all of the 123 Legionella isolates tested, with each species showing a specific profile. Among the 15 serogroups of Legionella pneumophila, eight patterns were obtained. For the 45 field strains, the randomly amplified polymorphic DNA (RAPD) technique and intergenic 16S-23S ribosomal spacer PCR analysis (ITS 16-23S) were also used. Altogether, these three methods allowed the identification of all of strains tested. However, ribotyping has proven to be more effective than the other methods.
...
PMID:Identification of Legionella species by ribotyping and other molecular methods. 1255 87

Photoreactivation of Legionella pneumophila after the inactivation by low-pressure (LP) or medium-pressure (MP) UV lamp was investigated in comparison with that of Escherichia coli. An endonuclease sensitive site (ESS) assay was used to determine the number of UV-induced pyrimidine dimers in the genome DNA of L. pneumophila or E. coli, while the survival ratio of each bacterium was also investigated by cultivation methods. L. pneumophila performed photoreactivation with almost complete repair of pyrimidine dimers associated with the quick recovery of survival ratio. A 3 log inactivation of L. pneumophila by LP or MP UV lamp was, respectively, resulted in 0.5 log or 0.4 log inactivation when photoreactivation was completed. Interestingly, L. pneumophila performed equivalent photoreactivation after LP and MP UV lamp exposures while photoreactivation of E. coli was significantly repressed after the inactivation by MP UV lamp. This study indicated that an attention would be required to design and operate a UV disinfection system targeting L. pneumophila. It was further implied that E. coli would not correctly indicate the fate of L. pneumophila in UV disinfection systems when photoreactivation takes place.
...
PMID:Photoreactivation of Legionella pneumophila after inactivation by low- or medium-pressure ultraviolet lamp. 1520 6

The genome of the bacterium Xylella fastidiosa contains four ORFs (XF2721, XF2725, XF2739 and XF0295) related to the restriction modification type I system, ordinarily named R-M. This system belongs to the DNA immigration control region (ICR). Each ORF is related to different operon structures, which are homologues among themselves and with subunit Hsd R from the endonuclease coding genes. In addition, these ORFs are highly homologous to genes in Pseudomonas aeruginosa, Methylococcus capsulatus str. Bath, Legionella pneumophila, Helicobacter pylori, Xanthomonas oryzae pv. Oryzae and Silicibacter pomeroyi, as well as to genes from X. fastidiosa strains that infect grapevine, almond and oleander plants. This study was carried out on R-M ORFs from forty-three X. fastidiosa strains isolated from citrus, coffee, grapevine, periwinkle, almond and plum trees, in order to assess the genetic diversity of these loci through PCR-RFLP. PCR-RFLP analysis of the four ORFs related to the R-M system from these strains enabled the detection of haplotypes for these loci. When the haplotypes were defined, wide genetic diversity and a large range of similar strains originating from different hosts were observed. This analysis also provided information indicating differences in population genetic structures, which led to detection of different levels of gene transfer among the groups of strains.
...
PMID:Strain variability in the DNA immigration control region (ICR) of Xylella fastidiosa. 1612 7

DNA mismatch repair (MMR) repairs mispaired bases in DNA generated by replication errors. MutS or MutS homologs recognize mispairs and coordinate with MutL or MutL homologs to direct excision of the newly synthesized DNA strand. In most organisms, the signal that discriminates between the newly synthesized and template DNA strands has not been definitively identified. In contrast, Escherichia coli and some related gammaproteobacteria use a highly elaborated methyl-directed MMR system that recognizes Dam methyltransferase modification sites that are transiently unmethylated on the newly synthesized strand after DNA replication. Evolution of methyl-directed MMR is characterized by the acquisition of Dam and the MutH nuclease and by the loss of the MutL endonuclease activity. Methyl-directed MMR is present in a subset of Gammaproteobacteria belonging to the orders Enterobacteriales, Pasteurellales, Vibrionales, Aeromonadales, and a subset of the Alteromonadales (the EPVAA group) as well as in gammaproteobacteria that have obtained these genes by horizontal gene transfer, including the medically relevant bacteria Fluoribacter, Legionella, and Tatlockia and the marine bacteria Methylophaga and Nitrosococcus.
...
PMID:Evolution of the methyl directed mismatch repair system in Escherichia coli. 2669 49

Riboswitches are thought generally to function by modulating transcription elongation or translation initiation. In rare instances, ligand binding to a riboswitch has been found to alter the rate of RNA degradation by directly stimulating or inhibiting nearby cleavage. Here, we show that guanidine-induced pseudoknot formation by the aptamer domain of a guanidine III riboswitch from Legionella pneumophila has a different effect, stabilizing mRNA by protecting distal cleavage sites en masse from ribonuclease attack. It does so by creating a coaxially base-paired obstacle that impedes scanning from a monophosphorylated 5' end to those sites by the regulatory endonuclease RNase E. Ligand binding by other riboswitch aptamers peripheral to the path traveled by RNase E does not inhibit distal cleavage. These findings reveal that a riboswitch aptamer can function independently of any overlapping expression platform to regulate gene expression by acting directly to prolong mRNA longevity in response to ligand binding.
...
PMID:Widespread Protection of RNA Cleavage Sites by a Riboswitch Aptamer that Folds as a Compact Obstacle to Scanning by RNase E. 3321 19

We have identified a variety of proteins in species of the Legionella, Aeromonas, Pseudomonas, Vibrio, Nitrosomonas, Nitrosospira, Variovorax, Halomonas, and Rhizobia genera, which feature repetitive modules of different length and composition, invariably ending at the COOH side with Asp-Asp-x-Pro (DDxP) motifs. DDxP proteins range in size from 900 to 6200 aa (amino acids), and contain 1 to 5 different module types, present in one or multiple copies. We hypothesize that DDxP proteins were modeled by the action of specific endonucleases inserting DNA segments into genes encoding DDxP motifs. Target site duplications (TSDs) formed upon repair of staggered ends generated by endonuclease cleavage would explain the DDxP motifs at repeat ends. TSDs acted eventually as targets for the insertion of more modules of the same or different types. Repeat clusters plausibly resulted from amplification of both repeat and flanking TSDs. The proposed growth shown by the insertion model is supported by the identification of homologous proteins lacking repeats in Pseudomonas and Rhizobium. The 85 DDxP repeats identified in this work vary in length, and can be sorted into short (136-215 aa) and long (243-304 aa) types. Conserved Asp-Gly-Asp-Gly-Asp motifs are located 11-19 aa from the terminal DDxP motifs in all repeats, and far upstream in most long repeats.
...
PMID:Growth by Insertion: The Family of Bacterial DDxP Proteins. 3327 54


<< Previous 1 2 3

---