Analysis of genetic polymorphisms affecting the four phospholipase C (plc) genes in Mycobacterium tuberculosis complex clinical isolates

Microbiology ◽  
2004 ◽  
Vol 150 (4) ◽  
pp. 967-978 ◽  
Author(s):  
C. Viana-Niero ◽  
P. E. de Haas ◽  
D. van Soolingen ◽  
S. C. Leão
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Phospholipase C ◽  
Genetic Polymorphisms ◽  
Blot Hybridization ◽  
Southern Blot Hybridization ◽  
Clinical Isolates ◽  
Significant Similarity ◽  
Genomic Deletions ◽  
Genes Encoding ◽  
Mycobacterium Africanum

The Mycobacterium tuberculosis genome contains four highly related genes which present significant similarity to Pseudomonas aeruginosa genes encoding phospholipase C enzymes. Three of these genes, plcA, plcB and plcC, are organized in tandem (locus plcABC). The fourth gene, plcD, is located in a different region. This study investigates variations in plcABC and plcD genes in clinical isolates of M. tuberculosis, Mycobacterium africanum and ‘Mycobacterium canettii’. Genetic polymorphisms were examined by PCR, Southern blot hybridization, sequence analysis and RT-PCR. Seven M. tuberculosis isolates contain insertions of IS6110 elements within plcA, plcC or plcD. In 19 of 25 M. tuberculosis isolates examined, genomic deletions were identified, resulting in loss of parts of genes or complete genes from the plcABC and/or plcD loci. Partial plcD deletion was observed in one M. africanum isolate. In each case, deletions were associated with the presence of a copy of the IS6110 element and in all occurrences IS6110 was transposed in the same orientation. A mechanism of deletion resulting from homologous recombination of two copies of IS6110 was recognized in a group of genetically related M. tuberculosis isolates. Five M. tuberculosis isolates presented major polymorphisms in the plcABC and plcD regions, along with loss of expression competence that affected all four plc genes. Phospholipase C is a well-known bacterial virulence factor. The precise role of phospholipase C in the pathogenicity of M. tuberculosis is unknown, but considering the potential importance that the plc genes may have in the virulence of the tubercle bacillus, the study of isolates cultured from patients with active tuberculosis bearing genetic variations affecting these genes may provide insights into the significance of phospholipase C enzymes for tuberculosis pathogenicity.

scholarly journals Shifts in Abundance and Diversity of Mobile Genetic Elements after the Introduction of Diverse Pesticides into an On-Farm Biopurification System over the Course of a Year

2014 ◽  
Vol 80 (13) ◽  
pp. 4012-4020 ◽  
Author(s):  
Simone Dealtry ◽  
Peter N. Holmsgaard ◽  
Vincent Dunon ◽  
Sven Jechalke ◽  
Guo-Chun Ding ◽  
...  
Keyword(s):  
Blot Hybridization ◽  
Pcr Amplification ◽  
Southern Blot Hybridization ◽  
Mobile Genetic Elements ◽  
Replication Initiation ◽  
Genetic Elements ◽  
Class 1 ◽  
Genes Encoding ◽  
Abundance And Diversity ◽  
And Shifts

ABSTRACTBiopurification systems (BPS) are used on farms to control pollution by treating pesticide-contaminated water. It is assumed that mobile genetic elements (MGEs) carrying genes coding for enzymes involved in degradation might contribute to the degradation of pesticides. Therefore, the composition and shifts of MGEs, in particular, of IncP-1 plasmids carried by BPS bacterial communities exposed to various pesticides, were monitored over the course of an agricultural season. PCR amplification of total community DNA using primers targeting genes specific to different plasmid groups combined with Southern blot hybridization indicated a high abundance of plasmids belonging to IncP-1, IncP-7, IncP-9, IncQ, and IncW, while IncU and IncN plasmids were less abundant or not detected. Furthermore, the integrase genes of class 1 and 2 integrons (intI1,intI2) and genes encoding resistance to sulfonamides (sul1,sul2) and streptomycin (aadA) were detected and seasonality was revealed. Amplicon pyrosequencing of the IncP-1trfAgene coding for the replication initiation protein revealed high IncP-1 plasmid diversity and an increase in the abundance of IncP-1β and a decrease in the abundance of IncP-1ε over time. The data of the chemical analysis showed increasing concentrations of various pesticides over the course of the agricultural season. As an increase in the relative abundances of bacteria carrying IncP-1β plasmids also occurred, this might point to a role of these plasmids in the degradation of many different pesticides.

scholarly journals Molecular Investigation of hemolytic phospholipase C Encoding Genes in Clinical Isolates of Pseudomonas aeruginosa

2018 ◽  
Vol 9 (SPL1) ◽  
Author(s):  
Rasha Hadi Saleh ◽  
Habeeb S Naher ◽  
Mohammed AK Al-saadi
Keyword(s):  
Phospholipase C ◽  
Virulence Genes ◽  
Clinical Isolates ◽  
Clinical Samples ◽  
Burn Wound ◽  
Molecular Investigation ◽  
Genes Encoding ◽  
Stool Samples ◽  
Polymerase Chain ◽  
Encoding Genes

This study is aimed to isolate P.aeruginosa from different clinical cases and to detect the prevalence of virulence genes encoding hemolytic phospholipase C(plcH)in these clinical isolates. In this study a total of 422 clinical samples including burn,wound,ear,urine,abscess and stool were aseptically taken from out- and inpatients who admitted into two hospitals in Hilla City (Teaching Al-Hilla Hospital and Babylon Hospital for Maternity and children during a period of three months. All samples were subjected to bacterial cultivation for the isolation of P.aeruginosa. The isolated P.aeruginosa was diagnosed depended on morphological,biochemical and molecular standard characteristics. Hemolytic phospholipase Cencoding genes(plcH) were detected by PCR and the amplification products were separated in 1% agarose gels containing ethidium bromide. Out of 422 samples,P.aeruginosa was isolated from 54 samples (12.8%). The distribution of these isolates were: 22 (55%) from burn samples,2; (50%) from diabitics foot samples,8 (14.8%) from wound samples, 8 (32%) from ear samples,3 (11%) from abscess samples, 7 (4%) from stool samples,4 (4%) from urine samples and 0 sputum samples. The genotypic properties of hemolytic phospholipase C (plcH )toxins was detected by polymerase chain reaction (PCR). The results of this study revealed that(plcH )gene found in 13/20 (65%)of isolates.

scholarly journals Novel Genetic Polymorphisms That Further Delineate the Phylogeny of the Mycobacterium tuberculosis Complex

2006 ◽  
Vol 188 (12) ◽  
pp. 4271-4287 ◽  
Author(s):  
Richard C. Huard ◽  
Michel Fabre ◽  
Petra de Haas ◽  
Luiz Claudio Oliveira Lazzarini ◽  
Dick van Soolingen ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Genomic Deletions ◽  
History Of ◽  
Species Specific ◽  
Mycobacterium Africanum ◽  
Mycobacterium Microti ◽  
First Time ◽  
Fine Tune

ABSTRACT In a previous report, we described a PCR protocol for the differentiation of the various species of the Mycobacterium tuberculosis complex (MTC) on the basis of genomic deletions (R. C. Huard, L. C. de Oliveira Lazzarini, W. R. Butler, D. van Soolingen, and J. L. Ho, J. Clin. Microbiol. 41:1637-1650, 2003). That report also provided a broad cross-comparison of several previously identified, phylogenetically relevant, long-sequence and single-nucleotide polymorphisms (LSPs and SNPs, respectively). In the present companion report, we expand upon the previous work (i) by continuing the evaluation of known MTC phylogenetic markers in a larger collection of tubercle bacilli (n = 125), (ii) by evaluating additional recently reported MTC species-specific and interspecific polymorphisms, and (iii) by describing the identification and distribution of a number of novel LSPs and SNPs. Notably, new genomic deletions were found in various Mycobacterium tuberculosis strains, new species-specific SNPs were identified for “Mycobacterium canettii,” Mycobacterium microti, and Mycobacterium pinnipedii, and, for the first time, intraspecific single-nucleotide DNA differences were discovered for the dassie bacillus, the oryx bacillus, and the two Mycobacterium africanum subtype I variants. Surprisingly, coincident polymorphisms linked one M. africanum subtype I genotype with the dassie bacillus and M. microti with M. pinnipedii, thereby suggesting closer evolutionary ties within each pair of species than had been previously thought. Overall, the presented data add to the genetic definitions of several MTC organisms as well as fine-tune current models for the evolutionary history of the MTC.

scholarly journals Comparison of Mycobacterium tuberculosis Genomes Reveals Frequent Deletions in a 20 kb Variable Region in Clinical Isolates

Yeast ◽  
2000 ◽  
Vol 1 (4) ◽  
pp. 272-282
Author(s):  
Timothy B. L. Ho ◽  
Brian D. Robertson ◽  
G. Michael Taylor ◽  
Rory J. Shaw ◽  
Douglas B. Young
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Hot Spots ◽  
High Frequency ◽  
Biological Diversity ◽  
Variable Region ◽  
Clinical Isolates ◽  
Insertion Element ◽  
Genomic Deletions ◽  
Nucleotide Repeats ◽  
Strain H37rv

The Mycobacterium tuberculosis complex is associated with a remarkably low level of structural gene polymorphism. As part of a search for alternative forms of genetic variation that may act as a source of biological diversity in M. tuberculosis, we have identified a region of the genome that is highly variable amongst a panel of unrelated clinical isolates. Fifteen of 24 isolates examined contained one or more copies of the M. tuberculosis-specific IS6110 insertion element within this 20 kb variable region. In nine of the isolates, including the laboratory-passaged strain H37Rv, genomic deletions were identified, resulting in loss of between two and 13 genes. In each case, deletions were associated with the presence of a copy of the IS6110 element. Absence of flanking tri- or tetra-nucleotide repeats identified homologous recombination between adjacent IS6110 elements as the most likely mechanism of the deletion events. IS6110 insertion into hot-spots within the genome of M. tuberculosis provides a mechanism for generation of genetic diversity involving a high frequency of insertions and deletions.

scholarly journals Novel Gyrase Mutations in Quinolone-Resistant and -Hypersusceptible Clinical Isolates of Mycobacterium tuberculosis: Functional Analysis of Mutant Enzymes

2006 ◽  
Vol 50 (1) ◽  
pp. 104-112 ◽  
Author(s):  
Alexandra Aubry ◽  
Nicolas Veziris ◽  
Emmanuelle Cambau ◽  
Chantal Truffot-Pernot ◽  
Vincent Jarlier ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Dna Cleavage ◽  
Multidrug Resistant ◽  
Quinolone Resistance ◽  
Clinical Isolates ◽  
Resistance Mutations ◽  
Drug Induced ◽  
Mutant Proteins ◽  
Highly Active ◽  
Genes Encoding

ABSTRACT Mutations in the DNA gyrase GyrA2GyrB2 complex are associated with resistance to quinolones in Mycobacterium tuberculosis. As fluoroquinolones are being used increasingly in the treatment of tuberculosis, we characterized several multidrug-resistant clinical isolates of M. tuberculosis carrying mutations in the genes encoding the GyrA or GyrB subunits associated with quinolone resistance or hypersusceptibility. In addition to the reported putative quinolone resistance mutations in GyrA, i.e., A90V, D94G, and D94H, we found that the GyrB N510D mutation was also associated with ofloxacin resistance. Surprisingly, several isolates bearing a novel combination of gyrA T80A and A90G changes were hypersusceptible to ofloxacin. M. tuberculosis GyrA and GyrB subunits (wild type [WT] and mutants) were overexpressed in Escherichia coli, purified to homogeneity, and used to reconstitute highly active gyrase complexes. Mutant proteins were produced similarly from engineered gyrA and gyrB alleles by mutagenesis. MICs, enzyme inhibition, and drug-induced DNA cleavage were determined for moxifloxacin, gatifloxacin, ofloxacin, levofloxacin, and enoxacin. Mutant gyrase complexes bearing GyrA A90V, D94G, and D94H and GyrB N510D were resistant to quinolone inhibition (MICs and 50% inhibitory concentrations [IC50s] at least 3.5-fold higher than the concentrations for the WT), and all, except the GyrB mutant, were less efficiently trapped as a quinolone cleavage complex. In marked contrast, gyrase complexes bearing GyrA T80A or A90G were hypersusceptible to the action of many quinolones, an effect that was reinforced for complexes bearing both mutations (MICs and IC50s up to 14-fold lower than the values for the WT). This is the first detailed enzymatic analysis of hypersusceptibility and resistance in M. tuberculosis.

scholarly journals Identification of a New DNA Region Specific for Members of Mycobacterium tuberculosis Complex

1998 ◽  
Vol 36 (4) ◽  
pp. 937-943 ◽  
Author(s):  
Juana Magdalena ◽  
Anne Vachée ◽  
Philip Supply ◽  
Camille Locht
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Dna Amplification ◽  
Target Sequence ◽  
Two Component System ◽  
Tuberculosis Complex ◽  
Specific Pcr ◽  
Length Polymorphisms ◽  
Genes Encoding ◽  
Mycobacterium Africanum ◽  
Mycobacterium Microti

The successful use of DNA amplification for the detection of tuberculous mycobacteria crucially depends on the choice of the target sequence, which ideally should be present in all tuberculous mycobacteria and absent from all other bacteria. In the present study we developed a PCR procedure based on the intergenic region (IR) separating two genes encoding a recently identified mycobacterial two-component system named SenX3-RegX3. The senX3-regX3 IR is composed of a novel type of repetitive sequence, called mycobacterial interspersed repetitive units (MIRUs). In a survey of 116Mycobacterium tuberculosis strains characterized by different IS6110 restriction fragment length polymorphisms, 2 Mycobacterium africanum strains, 3 Mycobacterium bovis strains (including 2 BCG strains), and 1Mycobacterium microti strain, a specific PCR fragment was amplified in all cases. This collection included M. tuberculosis strains that lack IS6110 ormtp40, two target sequences that have previously been used for the detection of M. tuberculosis. No PCR fragment was amplified when DNA from other organisms was used, giving a sensitivity of 100% and a specificity of 100% in the confidence limit of this study. The numbers of MIRUs were found to vary among strains, resulting in six different groups of strains on the basis of the size of the amplified PCR fragment. However, the vast majority of the strains (approximately 90%) fell within the same group, containing two 77-bp MIRUs followed by one 53-bp MIRU.

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