Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Spirochaeta”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources

Studies on the life cycle of spirochetes; the life cycle of the Nichols pathogenic Treponema pallidum in the rabbit testis as seen by phase contrast microscopy.

A series of observations with the phase contrast microscope on the occurrence of a complex life cycle in the pathogenic Treponema pallidum as it occurs in the syphilitic rabbit testis has been presented and it seems likely from these observations that there are two means of vegetative reproduction, consisting of (1) transverse division (the most important under usual conditions); and (2) the production of gemmae or buds which eventuate into unispirochetal cysts comparable to those described for saprophytic forms, within each of which single spirochetes develop and differentiate, and from which they subsequently emerge. In addition preliminary evidence is presented which suggests that a more complex process is involved in which multispirochetal cysts develop following aggregation of two or more organisms. Within each of these larger cysts numerous organisms develop and subsequently emerge as tangled ropes. Following emergence, they subsequently undergo transverse division and gemmae formation, and so reproduce vegetatively. Subsequent papers will elaborate upon these processes.

Animals↗

INTERFERENCE BETWEEN "SEX-RATIO" AGENTS OF DROSOPHILA WILLISTONI AND DROSOPHILA NEBULOSA.

Interference between two "sex-ratio" agents-that is, treponemalike spirochetes-of different origin, one from Drosophila willistoni and the other from D. nebulosa, was demonstrated by experiments in vivo and in vitro. When the two sex-ratio agents were combined in females of the Oregon-R strain of D. melanogaster, expression of the sex-ratio condition was temporarily interrupted. Several lines of evidence indicate that a substance produced by the sex-ratio agent of D. nebulosa may kill or incapacitate the sex-ratio agent of D. willistoni.

Animals↗

COLONIAL GROWTH OF ANAEROBIC SPIROCHETES ON SOLID MEDIA.

Hardy, Paul H., Jr. (The Johns Hopkins University School of Medicine, Baltimore, Md.), Young C. Lee, and E. Ellen Nell. Colonial growth of anaerobic spirochetes on solid media. J. Bacteriol. 86:616-626. 1963.-A total of 14 strains of treponemes and one of Borrelia vincentii were cultivated as colonies on agar plates inoculated under ordinary atmospheric conditions, but incubated anaerobically. Every spirochete strain produced diffuse colonies with growth located primarily in the agar; in addition, eight treponeme strains also produced discrete colonies with surface growth. These represented stable colonial variants in several strains, and in one the spirochetes in the surface colonies showed permanently altered cellular morphology. Sufficient variation in colonial morphology was noted between strains to suggest that this may have some value in further classification of this group of microorganisms. Several conditions contributed to the successful growth of all strains as colonies, the most important of which was the use of a firm jelling agar preparation, Ionagar No. 2, that permitted preparation of plates with a final agar concentration of 0.7%. Agar concentrations of 0.9%, or above, in media inhibited treponeme growth.

Agar↗