Differentiation of Mycobacterium tuberculosis Strains by Use of a Nonradioactive Southern Blot Hybridization Method

1991 ◽  
Vol 163 (4) ◽  
pp. 904-907 ◽  
Author(s):  
B. C. Ross ◽  
K. Raios ◽  
K. Jackson ◽  
A. Sievers ◽  
B. Dwyer
Microbiology ◽  
2004 ◽  
Vol 150 (4) ◽  
pp. 967-978 ◽  
Author(s):  
C. Viana-Niero ◽  
P. E. de Haas ◽  
D. van Soolingen ◽  
S. C. Leão

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.


Genomics ◽  
1994 ◽  
Vol 22 (1) ◽  
pp. 127-136 ◽  
Author(s):  
Atsushi Fukushima ◽  
Kousaku Okubo ◽  
Hidehiko Sugino ◽  
Naohiro Hori ◽  
Ryo Matoba ◽  
...  

1988 ◽  
Vol 34 (1) ◽  
pp. 50-52
Author(s):  
Chieko Suzuki ◽  
Noriko Tomita ◽  
Eiichi Uchiyama ◽  
Akio Ishii ◽  
Takeshi Nishizaki ◽  
...  

2000 ◽  
Vol 38 (3) ◽  
pp. 1131-1135 ◽  
Author(s):  
D. De Groote ◽  
R. Ducatelle ◽  
L. J. van Doorn ◽  
K. Tilmant ◽  
A. Verschuuren ◽  
...  

Recently, a new 16S ribosomal DNA-based PCR assay was developed for the specific detection of “Candidatus Helicobacter suis” (former “Gastrospirillum suis”) in porcine gastric samples. In the present study, this PCR assay was compared to three other invasive diagnostic methods (rapid urease test, immunohistochemistry, histologic analysis by Giemsa staining). Antral stomach samples from 200 slaughterhouse pigs from Belgium and The Netherlands were examined. Bacterial presence was determined in 77% (154 of 200) of the samples by PCR in combination with Southern blot hybridization, 56% (111 of 200) of the samples by immunohistochemistry, 61% (122 of 200) of the samples by urease testing (20 h postinoculation [p.i.]), 36% (71 of 200) of the samples by urease testing (3 h p.i.), and 33% (65 of 200) of the samples by Giemsa staining. The intrinsic specificity of the PCR assay was assessed by Southern blot analysis with an “Candidatus H. suis”-specific probe and sequencing of PCR products. Interassay sensitivity and specificity values were assessed for each test by pairwise comparisons between tests. Agreement between tests was evaluated by calculating Cohen's kappa coefficient. From that analysis, the PCR assay was considered the most reliable benchmark. Microscopic detection of immunohistochemically labeled or Giemsa-stained “Candidatus H. suis” cells in stomach sections proved to be highly specific (100%) but relatively insensitive (72 and 42%, respectively) compared to the PCR assay. A longer incubation time of the urease test improved its sensitivity considerably (74 versus 55%) but was accompanied by a loss of specificity (72 versus 93%). In conclusion, we found the “Candidatus H. suis”-specific PCR assay to be a sensitive and reliable diagnostic method for the detection of “Candidatus H. suis” in the stomachs of pigs and could prove to be a valuable tool for further epidemiological studies both for “Candidatus H. suis”- and for “Helicobacter heilmannii” type 1-related research.


Genome ◽  
1992 ◽  
Vol 35 (3) ◽  
pp. 478-491 ◽  
Author(s):  
Masaki Kuro-o ◽  
Tsutomu Hikida ◽  
Sei-ichi Kohno

Variations in repetitive DNA were examined in nine salamander species of the genera Hynobius and Onychodactylus. The data from Southern blot hybridization were processed by Manhattan distance analysis, and unrooted trees were drawn. The resulting trees suggest that the genus Hynobius can be divided into three groups: group 1 contains only H. retardatus with 40 chromosomes; group 2 contains H. kimurae, which has 58 chromosomes and is a mountain-brook type of Hynobius (this group probably contains all mountain-brook types of Hynobius with 58 chromosomes); and group 3 contains the other six pond-type species examined here, each with 56 chromosomes. Group 3 probably contains all species of Hynobius with 56 chromosomes. Furthermore, group 3 can be further separated into two groups: the first group includes H. leechii, H. tsuensis, H. nebulosus, H. nigrescens, and H. tokyoensis from Chita; and the second group includes H. tokyoensis (except the population from Chita) and H. lichenatus. According to this analysis and other information, it seems that the population from Aichi Prefecture, which belongs to H. tokyoensis, should be identified as H. nebulosus. Furthermore, it appears that the genus Onychodactylus is phylogenetically distant from Hynobius and Salamandrella.Key words: Hynobius, repetitive DNA, Southern blot hybridization, phylogenetics, neighbor-joining method.


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