Common Deoxyribonucleic Acid Sequences in Mycoplasma genitalium and Mycoplasma pneumoniae Genomes

Abstract

Southern blot hybridization of digested deoxyribonucleic acids (DNAs) of Mycoplasma ,genitalium, M . pneumoniae, and M . gallisepticum with probes made of total DNA of any one of these mycoplasmas revealed hybridization bands additional to those containing ribosomal ribonucleic acid (rRNA) gene sequences, which were identifiable by specific rRNA gene probes. The number and intensity of these additional bands were most pronounced with the M . genitalium-M. pneumoniae pair, which shares major antigenic determinants. Hybridization with M . pulmonis and Spiroplasma citri DNAs as probes revealed only the rRNA gene bands in digested DNAs of M . genitalium, M . pneumoniae, and M . gallisepticum. DNA-DNA hybridization tests in solution, with M . genitalium and M . pneumoniae DNA as probes, corroborated the Southern blotting data by showing the highest homology values between M . genitalium and M . pneumoniae (6.5 to 8.1 %), lower with M . gallisepticum (3.5 to 4.0%), and lowest with S. citri (0.5 to 0.9%). The new hybridization approach provides visual evidence for genetic relatedness between M . genitalium and M . pneumoniae and may facilitate the identification and cloning of genomic DNA segments carrying genes shared by two or more mycoplasmas.The new methodology of molecular genetics has provided useful tools for establishing genetic relatedness among bacteria, thus influencing bacterial taxonomy and phylogeny in a most profound way. Methods based on comparison of deoxyribonucleic acid (DNA) cleavage patterns by restriction endonucleases (21) and on hybridization patterns of cleaved DNA with ribosomal ribonucleic acid (rRNA) gene probes (17, 18; S. Razin and D. Yogev, J. Pediatr. Infect. Dis., in press) have recently been added to the longestablished DNA base composition and DNA homology tests (11). In the present communication, we propose another method for assessment of genetic relatedness between bacteria, based on detection of common genomic DNA sequences, as revealed by Southern blot hybridization of digested DNA of one organism with nick-translated total DNA of another organism. Mycoplasma genitalium and M. pneumoniae were selected as major test organisms, since the basis for the similarities exhibited by these two human mycoplasmas has become an important issue in current mycoplasma research (5, 7, 10, 12, 13, 24).The recently discovered M . genitalium, isolated from the urethras of nongonococcal urethritis patients (25), shows a remarkable resemblance to the well-established human pathogen M . pneumoniae in cell shape, possession of a tip structure, complex nutritional requirements, adherence ability (4, 14, 26), and antigenic structure (5, 7, 10, 12-14, 24). Nevertheless, genomic analysis indicates that these two organisms represent two distinct species by currently accepted criteria (11). Thus, the guanine plus cytosine content of the M . genitalium genome is 32.4 5 1.0 mol% (26), compared with the value of 38.6 to 40.8 mol% for the M . pneumoniae genome (20). The cleavage patterns of the DNAs of the two m...

Mycoplasma adhesion

“…Immunoblots show marked serological cross-reactivity between M. genitalium and M . pneumoniae cell proteins, supported by the significant sharing of genomic sequences between the two mycoplasmas (Yogev & Razin, 1986). Yet, despite the marked relatedness to M. pneumoniae, there is no doubt that M. genitalium deserves the status of a separate species.…”

“…Yet, despite the marked relatedness to M. pneumoniae, there is no doubt that M. genitalium deserves the status of a separate species. This is based on the significant difference in genomic DNA content [about 33mol% guanine + cytosine (G + C) in M. genitalium, compared to 40 mol% in M. pneumoniae], DNA homology values between the two mycoplasmas lower than 8% (Yogev & Razin, 1986), totally different genomic cleavage patterns of the two organisms ) and a marked difference in genome size. While the values reported for the M. pneumoniae genome are in the 800 kb range (Wenzel & Herrmann, 1989;Krause & Mawn, 1990;) the genome of M. genitalium is less than 600 kb in size Colman et al, 1990b), the smallest genome recorded for any mycoplasma and, in fact, for a self-replicating organism.…”

Detection of Mycoplasma pneumoniae by using the polymerase chain reaction

“…1A). The DNA targets were total DNA populations from M. pneumoniae and various other species generally found in the human respiratory tract and from M. genitalium, which is the closest known organism to M. pneumoniae (22). The MP5 clone gave a positive hybridization signal only with M. pneumoniae DNA.…”

Mycoplasma genitalium and Mycoplasma pneumoniae Share a 67 Kilodalton Protein as a Main Cross‐Reactive Antigen

“…Both species have several common features such as glucose fermentation, complex nutritional requirements, and adherence of erythrocytes to the colonies. Genomic homology of DNAs between both strains analyzed by DNA-DNA hybridization was only 1.8 to 8% (10,19), suggested that M. genitalium might have evolved independently of other human mycoplasma species, including M. pneumoniae (5). It has been demonstrated that monoclonal antibody (MAb) specific to the P1 protein (168 kDa) which is the major adhesin of M. pneumoniae cross-reacted with 100 kDa protein which is a putative adhesin of M. genitalium (3).…”

“…Mycoplasma genitalium and Mycoplasma pneumoniae are genetically (4,19) and serologically (2, 3, 9-11, 16, 20) close-related organisms that colonize in humans. M. genitalium is rarely isolated from human urethral specimens (12,18) and recently from throat specimens of military recruits (1), but the pathogenicity of this organism has not been assessed.…”