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Biomedical subjects

H Krauss

Publications and source records attributed to H Krauss.

At least 127 records · Page 7Linked to original sources
PubMed1980

Giant cell formation in Acholeplasma laidlawii, strain JA1.

Striking alterations, which looked like blebs, were observed in colonies of Acholeplasma laidlawii, strain JA 1. "Craters" were seen on the surface of these colonies by scanning electron microscopy. In addition, giant cells of acholeplasma, up to 14 microns in diameter, i.e. approximately 20 times the size of a normal A. laidlawii cell, were visible in the colonies. The large forms were surrounded by a unit membrane. After infection with group 1 and group 2 mycoplasma-viruses, the proportion of altered colonies and the number of large cells within these colonies increased. A strain of A. laidlawii, which was not susceptible to infection with the three known acholeplasma-viruses did not exhibit comparable morphological changes. The development of the giant cells can be explained either by cell fusion or by a lag of cell division behind genome replication. Blebs and "craters" may result from the destruction of mycoplasma organisms within the complex structure of the colony. There is also suggestive evidence that strain JA 1 carries a virus in some cryptic form.

Acholeplasma laidlawii↗
PubMed1979

Electron microscopic studies on the attachment of Mycoplasma pneumoniae to guinea pig erythrocytes.

A mechanism of pathogenicity of Mycoplasma pneumoniae is its ability to attach to the surface of mammalian cells. It has previously been demonstrated by others that M. pneumoniae adheres with a specialized terminal structure, the "tip," to ciliated epithelial cells of the respiratory tract. In this report we show by electron microscopy that M. pneumoniae adsorbs with membrane sites other than the tip to guinea pig erythrocytes.

Animals↗
PubMed1979

[A method for production of Coxiella burnetii antigen and cell walls by guanidiniumchloride extraction (author's transl)].

By use of 6-molar guanidinium chloride a potent Coxiella burnetii antigen could be produced for diagnostic purposes from infected yolk sacs, with little technical expense. This treatment did not only a cause remarkably purifying effect (Tab. 1) but also the extraction of soluble cytoplasmic substance. From guanidinium chloride-treated suspensions a highly purified and uniform suspension of cell walls could be separated by Saccharose Density Gradient centrifugation (Fig. 2). Guanidine extracted organisms retained their full antigenic potential with respect to Phase I and Phase II and lacked anticomplementary activity. Such preparations can be used for serological tests like complement fixation reaction or Enzyme Linked Immunosorbent Assay and are particularly suitable for biochemical studies of Phase antigens of Coxiella burnetii.

Antigens, Bacterial↗
PubMed1978

[Seroepidemiological investigations in domestic ruminants from Egypt, Somalia and Jordan for the demonstration of complement fixing antibodies against Rickettsia and Chlamydia (author's transl)].

1450 random serum samples of domestic ruminants from Egypt, Somalia and Jordan were investigated for complement fixing antibodies against Rickettsia and Chlamydia. Between 1.5 and 3.4% of the samples from the animals investigated had antibodies against the RMSF-group of Rickettsia, with exception of the sera from Somalian cattle and sheep from Jordan. Antibodies against Rickettsia of the Typhus-group were found in 4 cattle and 1 goat from Jordan and 2 sheep from Egypt; by agglutination test with type-specific antigen they were identified as antibodies against R. typhi. Using 2 different antigens, antibodies against Coxiella burnetii were found in every population tested. The prevalence was 2.0 to 12.2%, with the exception of cattle in Somalia, where only 1 positive serum (0.2%) was found. 27% of the serum samples from Jordan and 22% from Egypt but none of the 802 samples from Somalia had antibodies against Chlamydia. The results are discussed under an epidemiological point of view.

Animals↗
PubMed1978

Electrophoretic characterization of bovine mycoplasma and acholeplasma reference strains.

Phenol-acetic acid-water extracts of 13 recognized mycoplasma and acholeplasma reference strains of bovine habitat were subjected to polyacrylamide gel electrophoresis. A characteristic electrophoretic profile was obtained for each strain and the relative mobility (Rm) values of the major protein fractions were determined. All examined strains had a common protein band of 33.3 Rm value. Comparison of electrophoretic patterns obtained from different reference strains revealed 2 to 7 protein bands with the same Rm values in a number of strains. A possible correlation with antigenic relatedness is discussed.

Acholeplasma↗
PubMed1977

[The behavior of the Q-fever agent, Coxiella burnetii, in birds. 3. Experimental infection of quail].

After simultaneous aerogenic and alimentary infection of quail by intra-nasal inoculation of a suspension of C. burnetii, the agent was reisolated 6 h after infection from lung and gut, from the 3rd day on from the spleen, at the 8th and 10th day from blood, and from the 8th day on from liver and kidney. C.burnetii was found in various organs up to 21 days after infection. In the majority of birds agglutinating antibodies could be demonstrated from the 18th day up to termination of the experiment 66 days after infection. On the basis of these results the course of a C. burnetii infection in birds is discussed.

Animals↗
PubMed1977

Ultrastructural investigations on surface structures involved in Coxiella burnetii phase variation.

By using the cytochemical staining procedure with concanavalin A, horseradish peroxidase, and diaminobenzidine, no surface carbohydrates with terminal alpha-glucosyl or sterically closely related residues could be detected on the cell walls of Coxiella burnetii phases I and II. Using a polycationized ferritin derivative as a cytochemical probe, anionic binding sites were visualized in the electron microscope on cell membranes of C. burnetii phase II, but not on phase I organisms. The sites appeared to be masked in phase I particles. Anionic sites could be demonstrated on phase I organisms after treatment with NaIO4 or dimethyl sulfoxide. A number of different biological properties of C. burnetii phases I and II may depend on the presence or absence of a net negative charge on the surface of the cell walls of these organisms.

Acetone↗
PubMed1977

[Seroepidemiological investigations on the prevalence of rickettsial antibodies in man in the Federal Republic of Germany (author's transl)].

1,600 random serum samples from inhabitants of Hesse were investigated for rickettsial antibodies by complement fixation test. Antibodies were found in 19 samples (1,2%) against RMSF-group antigen with titers between 1:10 and 1:640. These results confirm recent reports on natural foci of such rickettsial infections in the Federal Republic of Germany. Antibodies against rickettsia of the Typhus-group or Coxiella burnetii could not be detected by the complement fixation reaction. None of the sera reacted with significant titer in the Weil-Felix-Test.

Antibodies, Bacterial↗