No abstract

1988. Nile red fluorescence demonstrates lipid in the envelope of vesicles from N2-fixing cultures of Frankia. Can. J. Microbiol. 34: 656-660. Using Nile red as a fluorescent stain for lipid, we investigated the composition of the envelope of vesicles of Frankia strain HFPCcI3 from cultures induced in N-free medium at 1 and 20 kPa 02. Vesicles and nitrogenase activity appeared in the cultures at both p 0 2 ; on average, vesicles viewed by dark-field microscopy were larger and had thicker envelopes at 20 kPa O2 than at 1 kPa 0 2 . Envelopes of Nile red-stained vesicles fluoresced red under incident green light. When samples of CcI3 were extracted through a lipid-solvent series and then stained, vesicles still fluoresced red but lacked a distinct peripheral fluorescent ring. These results are consistent with the view that the envelope of Frankia vesicles consists largely of lipid and serves as a barrier to diffusion of 0 2 .

Guinea pig boars were inoculated intraurethrally with the chlamydial agent of guinea pig inclusion conjunctivitis (GPIC). At the heights of their urethral infections, they were caged with sows in estrus. Whereas some of the sows had not been previously exposed to GPIC agent, others had received an intravaginal inoculation 5 to 8 weeks earlier. Those sows for which infected boars provided the first exposure were challenged by intravaginal inoculation 5 to 8 weeks later. Vaginal and conjunctival scrapings were taken regularly and stained for chlamydial inclusions. Titers of serum anti-GPIC antibodies and of vaginal secretary IgA anti-GPIC antibodies were determined by immunofluorescence. Our results show for the first time that a sexually acquired vaginal GPIC infection induces immunity to manual reinfection of the vagina. Because of the high incidence of secondary conjunctival infections among the vaginally infected sows, we could not provide a sound statistical basis for our tentative conclusion that manual infection of the vagina induces immunity to sexual reinfection. The results of our antibody titrations confirm previous work showing that vaginal GPIC infection induces formation of both serum antibody and vaginal secretary immunoglobulin A antibody.

Trichomes of two oscillatoriacean blue-green algae execute screw-like gliding motion, but the two organisms differ from each other with respect to the screw sense of motion. Electron microscopy of serial longitudinal sections reveals extracellular microfibrils which lie roughly parallel to streamlines at the surface of each organism. The author proposes that the microfibrils are oriented by shear in a zone just external to the outer unit membrane-like component of the cell wall.

No abstract