Motility and Multiplication of Mycoplasma pneumoniae

Bredt, W.

doi:10.1159/000162074

Cited by 37 publications

(47 citation statements)

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“…The coordination of gliding motility and cell division was noted previously (8,16,26); our findings support and extend the current understanding of that relationship. Gliding ceased as nascent P30 foci emerged, as expected.…”

Section: Discussionsupporting

confidence: 92%

“…By light microscopy M. pneumoniae cell division appears to begin with formation of a second terminal organelle adjacent to the first and the migration of one structure toward the opposite cell pole (16). Limits of resolution and the small size of the mycoplasma cell restrict the conclusions that might be drawn by light microscopy, but cell images by electron microscopy (17) as well as data correlating DNA content and the number and location of terminal organelles in fixed cells (18) are consistent with this model.…”

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confidence: 99%

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Terminal organelle development in the cell wall-less bacterium Mycoplasma pneumoniae

Hasselbring

Jordan

Krause

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Mycoplasmas are cell wall-less bacteria considered among the smallest and simplest prokaryotes known, and yet several species including Mycoplasma pneumoniae have a remarkably complex cellular organization highlighted by the presence of a differentiated terminal organelle, a membrane-bound cell extension distinguished by an electron-dense core. Adhesin proteins localize specifically to the terminal organelle, which is also the leading end in gliding motility. Duplication of the terminal organelle is thought to precede cell division, but neither the mechanism of its duplication nor its role in this process is understood. Here we used fluorescent protein fusions and time-lapse digital imaging to study terminal organelle formation in detail in growing cultures of M. pneumoniae. Individual cells ceased gliding as a new terminal organelle formed adjacent to an existing structure, which then migrated away from the transiently stationary nascent structure. Multiple terminal organelles often formed before cytokinesis was observed. The separation of terminal organelles was impaired in a nonmotile mutant, indicating a requirement for gliding in normal cell division. Examination of cells expressing two different fluorescent protein fusions concurrently established their relative order of appearance, and changes in the fluorescence pattern over time suggested that nascent terminal organelles originated de novo rather than from an existing structure. In summary, spatial and temporal analysis of terminal organelle formation has yielded insights into the nature of M. pneumoniae cell division and the role of gliding motility in that process.cell division ͉ gliding motility ͉ adherence ͉ fluorescent protein fusion M ycoplasma pneumoniae causes chronic infections of the human respiratory tract, including bronchitis and primary atypical or ''walking'' pneumonia, accounting for up to 30% of all community-acquired pneumonia, particularly among older children and young adults. M. pneumoniae infections can result in chronic or permanent lung damage, and a growing body of evidence supports a correlation with the onset, exacerbation, and recurrence of asthma. Furthermore, extrapulmonary sequelae are not uncommon, reflecting both invasive and immunopathological components to M. pneumoniae disease (1).In addition to its significant impact on public health, M. pneumoniae is intriguing from a biological perspective. Mycoplasmas have no cell wall and are among the smallest known cells, with M. pneumoniae having a cell volume only Ϸ5% of that of Escherichia coli. Likewise, at 816 kb the M. pneumoniae genome is among the smallest known for a cell capable of a free-living existence, lacking genes for cell wall production, de novo synthesis of nucleotides and amino acids, and twocomponent or other common bacterial transcriptional regulators (2, 3). Nevertheless, a remarkable level of structural complexity underlies what are otherwise considered minimal cells (4). Thus, experimental evidence indicated the presence of cytoskeletal structure and fu...

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Section: Discussionsupporting

confidence: 92%

mentioning

confidence: 99%

Terminal organelle development in the cell wall-less bacterium Mycoplasma pneumoniae

Hasselbring

Jordan

Krause

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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“…Wild-type M. pneumoniae cells commonly exhibit resting periods of various lengths and frequencies during their motility tracks (6,42). Because reduced satellite growth could result from increased resting frequencies rather than or in addition to reduced gliding velocities, we also examined the percentage of time that individual cells spent in intermittent resting periods during their motility tracks (percent time resting).…”

Section: Resultsmentioning

confidence: 99%

“…In order to quantitate gliding velocities for individual cells we modified a microcinematographic approach described over 30 years ago for M. pneumoniae (6) medium supplemented with gelatin (3% wt/vol) by passage through a 25-gauge needle seven times, divided into motility stocks, and stored at Ϫ80°C. Motility stocks were thawed, mixed with 500 l of fresh SP-4-3% gelatin-0.05 M HEPES (pH 7.2), passed through a 25-gauge needle five times to disperse cell aggregates, and inoculated into four-well borosilicate glass chambers, which were placed onto the observation stage of a Leica DM IRB microscope enclosed within an incubation chamber (Solent Scientific Limited, Portsmouth, United Kingdom) preheated to 37°C.…”

Section: Methodsmentioning

confidence: 99%

“…pneumoniae cells exhibit gliding motility, with the terminal organelle always the leading end (6), but details regarding the biological significance and the mechanism of gliding are largely unknown. Although the M. pneumoniae genome has been sequenced and twice annotated (11,19), close inspection reveals no homology to proteins known to be involved in bacterial motility of any type in walled bacteria.…”

mentioning

confidence: 99%

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Mutant Analysis Reveals a Specific Requirement for Protein P30 inMycoplasma pneumoniaeGliding Motility

2005

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The cell-wall-less prokaryote Mycoplasma pneumoniae, long considered among the smallest and simplest cells capable of self-replication, has a distinct cellular polarity characterized by the presence of a differentiated terminal organelle which functions in adherence to human respiratory epithelium, gliding motility, and cell division. Characterization of hemadsorption (HA)-negative mutants has resulted in identification of several terminal organelle proteins, including P30, the loss of which results in developmental defects and decreased adherence to host cells, but their impact on M. pneumoniae gliding has not been investigated. Here we examined the contribution of P30 to gliding motility on the basis of satellite growth and cell gliding velocity and frequency. M. pneumoniae HA mutant II-3 lacking P30 was nonmotile, but HA mutant II-7 producing a truncated P30 was motile, albeit at a velocity 50-fold less than that of the wild type. HA-positive revertant II-3R producing an altered P30 was unexpectedly not fully wild type with respect to gliding. Complementation of mutant II-3 with recombinant wild-type and mutant alleles confirmed the correlation between gliding defect and loss or alteration in P30. Surprisingly, fusion of yellow fluorescent protein to the C terminus of P30 had little impact on cell gliding velocity and significantly enhanced HA. Finally, while quantitative examination of HA revealed clear distinctions among these mutant strains, gliding defects did not correlate strictly with the HA phenotype, and all strains attached to glass at wild-type levels. Taken together, these findings suggest a role for P30 in gliding motility that is distinct from its requirement in adherence.Mycoplasmas are cell-wall-less prokaryotes with minimal genomes and limited biosynthetic capabilities, dictating a strict dependence on host species for survival in nature (43). Mycoplasma pneumoniae is a human pathogen primarily colonizing the respiratory tract. While the most common clinical manifestations of infection are tracheobronchitis and atypical or "walking" pneumonia (7,12,14,30), recent studies indicate a strong correlation with asthma (5, 24, 38), and extrapulmonary complications are not uncommon (53). Adherence of M. pneumoniae cells to host respiratory epithelium (cytadherence) is required for colonization and pathogenesis (20) and is mediated largely by a differentiated terminal organelle (9, 39). This well-defined apical structure is a membrane-bound extension of the mycoplasma cell distinguished ultrastructurally by an electron-dense core (4), which is a major constituent of the M. pneumoniae cytoskeleton (17, 35).M. pneumoniae cells exhibit gliding motility, with the terminal organelle always the leading end (6), but details regarding the biological significance and the mechanism of gliding are largely unknown. Although the M. pneumoniae genome has been sequenced and twice annotated (11, 19), close inspection reveals no homology to proteins known to be involved in bacterial motility of any type in walled bact...

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Organization and Assembly of the Mycoplasma pneumoniae Attachment Organelle

Balish

2006

Microbiology Monographs

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Motility and Multiplication of Mycoplasma pneumoniae

Cited by 37 publications

References 3 publications

Terminal organelle development in the cell wall-less bacterium Mycoplasma pneumoniae

Terminal organelle development in the cell wall-less bacterium Mycoplasma pneumoniae

Mutant Analysis Reveals a Specific Requirement for Protein P30 inMycoplasma pneumoniaeGliding Motility

Organization and Assembly of the Mycoplasma pneumoniae Attachment Organelle

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