Electron-microscopic immunohistochemical study of the localization of immunoglobulin G in the choroid plexus of the rat

Summary The localization of autologous antiperoxidase immunoglobulin G (IgG) was studied in the choroid plexus of Lewis rats immunized against horseradish peroxidase (HRP). This experiment was performed to study the permeability of the choroid plexus to intravascular IgG. It was shown that autologous IgG was present in the extravascular spaces. The transendothelial transfer appeared to occur mainly via the fenestrations and some interendothelial junctions. No transfer of IgG at the level of epithelial cells toward the cerebrospinal fluid was demonstrated. Interstitial spaces in contact with the connective-tissue cells of the choroid stroma were strongly labeled. The significance of these spaces remains hypothetical and raises the question of the fate of IgG from the interstitial space.This work has been partly supported by Crédits Recherche Universitaire, Paris-val de Marne.     

Drosophila Tubulin-Specific Chaperone E Recruits Tubulin around Chromatin to Promote Mitotic Spindle Assembly

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Photoreaction center of photosynthetic bacteria. 1. Further chemical characterization of the photoreaction center from Rhodospirillum rubrum.

The photoreaction center from Rhodospirillum rubrum contains about 90% protein, 6% pigment, mere traces of lipids, and no cytochromes. It also contains at least 1 mol of ubiquinone and 1 iron atom per mol. Its three-component polypeptide chains were isolated by preparative electrophoresis, and their molar stoichiometry was established as 1:1:1. The amino acid composition of the photoreaction center from strain S1 and from its subunits is reported. The protein as a whole contains about 65% nonpolar residues, and the degree of hydrophobicity of its subunits is alpha less than beta less than gamma. The minimal molecular weight based on the extinction coefficient and on the amino acid content is 90 000. This corresponds to a half-cystine mole number of 6.     

Immunofluorescent localization of a seminal vesicle proteinase inhibitor in the female reproductive tract of naturally inseminated mice

The indirect immunofluorescent technique was used to localize a low molecular weight, acid-stable proteinase inhibitor of seminal vesicle origin in the female reproductive tract of mice. In recently inseminated animals (0, 2, and 4 hr postcoitus) the inhibitor was localized in the copulatory plug, on the epithelia of the vaginal fornix and cervix, in the uterine lumen, and on the apical surface of the uterine epithelium. Ten hours postcoitus the inhibitor was found in localized areas on the uterine epithelium, in a sperm-leucocyte mass in the uterine lumen, and in the copulatory plug. The inhibitor was not found in females 24 hr postcoitus. The inhibitor could not be localized in the oviducts of any of the animals tested. The data are interpreted to mean that the inhibitor, transported to the female at ejaculation, coats the surface of the female reproductive tract protecting it from acrosomal enzymes or from invasion by spermatozoa or pathogens.