Biomedical subjects
Publications and source records attributed to W Bredt.
The gliding movements of freshly isolated Mycoplasma pulmonis cells were observed and measured. The motile cells had a characteristic appearance, an average speed of 0.4 to 0.7 micron/s, and a maximum speed of 1 micron/s.
Two liquid media and two agar media were compared for their sensitivity in the isolation of Ureaplasma urealyticum. 22 of the 144 urine specimens examined were positive. The U9-medium with low serum content showed a higher isolation rate and earlier results than a medium with 20% serum (Table 1). However some cultures grew sometimes better in the serum rich medium, suggesting a growth enhancing effect of urine in the U9-cultures. On agar more positive cases were detected with the A6-differential agar which showed urease-activity by brown color (MnO2), and less specimens were positive on A5C-agar without manganese sulfate (19 vs. 16). The number of colonies was only slightly lower on A5C-agar (Fig. 3). The darkbrown colonies on A6 (Fig. 1) were easy to detect and to count. Filtration of the urine specimens through a polycarbonate filter (0.4mum) reduced the number of bacterial contaminations, but resulted also in a lower isolation rate of ureaplasmas (13 of 22). This is probably caused by the tendency of ureaplasmas to attach to other structures e.g. epithelial cells (Fig. 2). For isolation of U. urealyticum from clinical specimens a combination of a liquid medium and a differential agar-medium is recommended.
The pathogenicity of mycoplasmas is caused by several factors, e.g. exotoxin, toxic properties of membrane components, exoenzymes, peroxide, and immunological factors. The absence of a rigid cell wall and the small genome tend to influence the interactions between mycoplasmas and host tissue. Mycoplasmas do not have a cell wass and are therefore resistant to the action of the host's lysozymes. They appear in some patients to be immunologically inconspicuous and in other patients they have been reported to have an immuno-suppressive effect. Recently there have been reports of central nervous system disorders due to mycoplasma. The pathogenic factors involved in these reactions have not been elucidated. Other aspects of Mycoplasma pneumoniae pathogenicity are also discussed.
The rate of appearance of red-colored formazan indicating reduction of 2,3,5,-triphenyltetrazolium chloride by Mycoplasma pneumoniae was dependent on the inoculum size. The test permits estimation of M. pneumoniae cells in preparations that cannot be counted by dilution methods.
In order to elucidate the pathogenetic importance of mycoplasma in amnionitis and in infectious syndrome of the amnion, the amniotic fluid of 185 healthy pregnant women was investigated for mycoplasma, bacteria and fungi. In no case mycoplasma were detected. This means that amniotic fluid is normally free of mycoplasma. If mycoplasma occurs in the amniotic fluid it has to be considered as a possible cause of amnionitis and infectious syndrome of the amnion.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The "toxic" effect of guinea pig serum (GPS) on Mycoplasma pneumoniae cells was tested under various conditions, using rounding and killing of the cells as test systems. Both activities could be inhibited by heat inactivation (56 C, 30 min). Killing required both Ca2+ and Mg2+, rounding only Mg2+. Both activities were temperature dependent and no rounding or killing occurred at 4C. Incomplete complement sequences with natural of artificial defects in C1, C4, or C6 resulted in lost or reduced killing. The rounding activity was only slightly affected. Anti-C3 antiserum blocked both phenomena; incubation of GPS with 10 mg of inulin per ml reduced the rounding activity, and the same treatment of GPS deficient in C4 inhibited rounding totally. Properdin factor D was shown to be necessary for rounding by GPS, with defects in either C1 or C4. By immune adherence bound C3b could be demonstrated on M. pneumoniae cells after GPS treatment, no antibodies against M. pneumoniae could be found in GPS by immune fluorescence. The results give evidence for complement being the toxic factor in GPS. Efficient killing requires the intact complement sequence. Furthermore, M. pneumoniae cells are able to activate the alternate pathway of complement. Activation of this pathway results in rounding of the cells, which are partly able to recover after this reaction. Biological consequences for the mycoplasmas are death or damage and possibly opsonization, even in the absence of specific antibodies. The host, too, is possibly affected by products of the reaction. The interaction of M. pneumoniae and complement could be involved in the early stages of the development of M. pneumoniae disease.
Mycoplasma pneumoniae cells are not phagocytized by peritoneal macrophages without opsonization. They are taken up after treatment with complement or antibody.
A microscopy test that used the typical shape of Mycoplasma pneumoniae cells growing on glass was investigated for its value for diagnostic purposes. Suspensions from 108 throat swabs were infected artificially with 102, 103, and 104 colony-forming units of three M. pneumoniae strains per ml. Agar medium, a diphasic medium, and the microscopy method with liquid medium in cover slip chambers were compared for isolation of the mycoplasmas. The mycoplasms were detected first by the microscopy method in nearly all concentrations tested. Typical M. pneumoniae cells could often be detected after 48 h. No differences were found between a laboratory strain and two low-passage strains. The experimental results suggest that under special circumstances the microscopy method could be a useful tool for isolation and identification of M. pneumoniae.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Cells of two strains of Mycoplasma hominis growing in liquid medium on a glass surface were observed continuously, and cinematographic pictures were taken. Most of the observed structures showed reversible changes of their shape, suggesting the presence of contractile material in membrane or cytoplasma. The frequency and speed of such variations were measured. The deformations seem to be related to multiplication. The mechanisms of these phenomena are unknown.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Cells of Mycoplasma hominis growing in laboratory media for the first time were observed by phase contrast and identified by their reaction to homologous antiserum.
Explore the source record for details and available documents.