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Insertion sequence typing of Mycobacterium tuberculosis: characterization of a widespread subtype with a single copy of IS6110

Fomukong NG, Tang TH, al-Maamary S, Ibrahim WA, Ramayah S, Yates M, et al.

Tuber. Lung Dis., 1994 Dec;75(6):435-40.
PMID: 7718832 DOI: 10.1016/0962-8479(94)90117-1

DNA fingerprinting with the insertion sequence IS6110 (also known as IS986) has become established as a major tool for investigating the spread of tuberculosis. Most strains of Mycobacterium tuberculosis have multiple copies of IS6110, but a small minority carry a single copy only. We have examined selected strains from Malaysia, Tanzania and Oman, in comparison with M. bovis isolates and BCG strains carrying one or two copies of IS6110. The insertion sequence appears to be present in the same position in all these strains, which suggests that in these organisms the element is defective in transposition and that the loss of transposability may have occurred at an early stage in the evolution of the M. tuberculosis complex.

Matched MeSH terms: DNA Transposable Elements/genetics*
Fulltext Identification of potential Campylobacter jejuni genes involved in biofilm formation by EZ-Tn5 Transposome mutagenesis

Teh AHT, Lee SM, Dykes GA

BMC Res Notes, 2017 May 12;10(1):182.
PMID: 28499399 DOI: 10.1186/s13104-017-2504-1

BACKGROUND: Biofilm formation has been suggested to play a role in the survival of Campylobacter jejuni in the environment and contribute to the high incidence of human campylobacteriosis. Molecular studies of biofilm formation by Campylobacter are sparse.
RESULTS: We attempted to identify genes that may be involved in biofilm formation in seven C. jejuni strains through construction of mutants using the EZ-Tn5 Transposome system. Only 14 mutants with reduced biofilm formation were obtained, all from one strain of C. jejuni. Three different genes of interest, namely CmeB (synthesis of multidrug efflux system transporter proteins), NusG (transcription termination and anti-termination protein) and a putative transmembrane protein (involved in membrane protein function) were identified. The efficiency of the EZ::TN5 transposon mutagenesis approach was strain dependent and was unable to generate any mutants from most of the strains used.
CONCLUSIONS: A diverse range of genes may be involved in biofilm formation by C. jejuni. The application of the EZ::TN5 system for construction of mutants in different Campylobacter strains is limited.

Matched MeSH terms: DNA Transposable Elements/genetics*
Fulltext Hemolysins and plasmid profiles of Vibrio parahaemolyticus

Vadivelu J, Puthucheary SD, Mitin A, Wan CY, van Melle B, Puthucheary JA

Southeast Asian J Trop Med Public Health, 1996 Mar;27(1):126-31.
PMID: 9031414

Forty clinical isolates of Vibrio parahaemolyticus were studied for the production of the thermostable direct hemolysin (TDH), and the TDH-related hemolysin (TRH) including the respective encoding genes, tdh and trh. The presence of TDH and its encoding genes were found amongst 95% of the strains, whereas the TRH was absent amongst these isolates. Thirty-two isolates were found to be plasmid-free, whereas eight isolates possessed plasmids with sizes ranging from 2.4 > or = 23 kb. Using a DNA probe coding for the homologous region of the tdh and trh, it was found that the tdh genes were present on the chromosomal DNA.

Matched MeSH terms: DNA Transposable Elements/genetics
Apolipoprotein B 5'-Ins/Del and 3'-VNTR polymorphisms in Chinese, malay and Indian singaporeans

Choong ML, Koay ES, Khaw MC, Aw TC

Hum. Hered., 1999 Jan;49(1):31-40.
PMID: 9858855

The allele frequencies for the apolipoprotein B (apo B) 5'-Ins/Del and 3'-VNTR polymorphisms varied significantly (p < 0.01) among Singaporeans of Chinese, Malay and Indian descent. We calculated the unbiased expected heterozygosities for the 5'-Ins/Del polymorphism as 0.3357, 0.1984 and 0.2418, and for the 3'-VNTR as 0.5980, 0.5260 and 0.6749, respectively, in the Chinese, Malays and Indians. Compared to heterozygosities reported for other populations, the Singaporeans differed from most Caucasians in having significantly lower values but were closely related to other non-Caucasians. Thirteen alleles, with a bimodal distribution, were observed at the 3'-VNTR polymorphic locus; the alleles occurring most frequently among the Chinese and Malays were of 35 or 53 repeats, and among the Indians, of 37 or 47 repeats. The Del allele was associated with elevated serum cholesterol (p = 0.023), LDL-cholesterol (LDL-C) (p = 0.001) in the Chinese, and apo B (p = 0.007) in the Indians. Likewise, the larger 3'-VNTR alleles (> 41 repeats) were associated with raised cholesterol (p = 0.018), LDL-C (p = 0.025), and triglyceride (p = 0.001) in the Chinese. The two polymorphisms were not in significant linkage disequilibrium (D = -0.0029, p = 0.494) in the three ethnic groups.

Matched MeSH terms: DNA Transposable Elements/genetics
Fulltext Genome Anatomy of Pyrenochaeta unguis-hominis UM 256, a Multidrug Resistant Strain Isolated from Skin Scraping

Toh YF, Yew SM, Chan CL, Na SL, Lee KW, Hoh CC, et al.

PLoS One, 2016;11(9):e0162095.
PMID: 27626635 DOI: 10.1371/journal.pone.0162095

Pyrenochaeta unguis-hominis is a rare human pathogen that causes infection in human skin and nail. P. unguis-hominis has received little attention, and thus, the basic biology and pathogenicity of this fungus is not fully understood. In this study, we performed in-depth analysis of the P. unguis-hominis UM 256 genome that was isolated from the skin scraping of a dermatitis patient. The isolate was identified to species level using a comprehensive multilocus phylogenetic analysis of the genus Pyrenochaeta. The assembled UM 256 genome has a size of 35.5 Mb and encodes 12,545 putative genes, and 0.34% of the assembled genome is predicted transposable elements. Its genomic features propose that the fungus is a heterothallic fungus that encodes a wide array of plant cell wall degrading enzymes, peptidases, and secondary metabolite biosynthetic enzymes. Antifungal drug resistance genes including MDR, CDR, and ERG11/CYP51 were identified in P. unguis-hominis UM 256, which may confer resistance to this fungus. The genome analysis of P. unguis-hominis provides an insight into molecular and genetic basis of the fungal lifestyles, understanding the unrevealed biology of antifungal resistance in this fungus.

Matched MeSH terms: DNA Transposable Elements/genetics
Combined use of ribotyping, PFGE typing and IS431 typing in the discrimination of nosocomial strains of methicillin-resistant Staphylococcus aureus

Yoshida T, Kondo N, Hanifah YA, Hiramatsu K

Microbiol. Immunol., 1997;41(9):687-95.
PMID: 9343819

We have previously reported the phenotypic characterization of methicillin-resistant Staphylococcus aureus (MRSA) clinical strains isolated in Malaya University Hospital in the period 1987 to 1989 using antibiogram, coagulase typing, plasmid profiles, and phage typing. Here, we report the analysis of the same strains with three genotyping methods; ribotyping, pulsed-field gel electrophoresis (PFGE) typing, and IS431 typing (a restriction enzyme fragment length polymorphism analysis using an IS431 probe). Ribotyping could discriminate 46 clinical MRSA strains into 5 ribotypes, PFGE typing into 22 types, and IS431 typing into 15 types. Since the differences of the three genotyping patterns from strain to strain were quite independent from one another, the combined use of the three genotyping methods could discriminate 46 strains into 39 genotypes. Thus, the powerful discriminatory ability of the combination was demonstrated.

Matched MeSH terms: DNA Transposable Elements/genetics*