Visualization of chitin-protein layer formation in Ascaris lumbricoides egg-shells

The formation of chitin-protein layer in Ascaris lumbricoides egg-shells was studied using the method of chitin structures visualization by means of derivatives of stilbene-disulfonic acid (Blankophor, Bayer, FRG). Intensive formation of chitin structures in A. lumbricoides egg-shell occurred only in fertilized females in a very short portion of uterus from the site of connection of the oviduct with the uterus up to 25-30 mm distally, i.e. in the section forming about one fifth or less than one sixth of length of adult female uterus. Already 3 mm from the beginning of uterus there was a thin layer on the surface of the fertilized eggs which contained chitin detectable by Blankophor visualization, whereas the chitin-protein layer on the shells could not be demonstrated histologically. The thickness of this chitin-protein complex increased distally. At 25 mm from the beginning of uterus the chitin layer was already complete and its thickness did not increase any more.