This flow is thus sustained solely by synchronized and localized patterns of ampullar
In prepubertal (PP) animals the morphologic identification of the ampullar, dorsal and ventral regions was not yet reliable; then, all the immunohistochemical and quantitative studies were performed in two different zones: the prostate (including the three undifferentiated ventral, dorsal and ampullar regions) and the duct zone (easily identified throughout all the age groups).
For each antigen employed, the immunoreactive nerve fibres were evaluated in periglandular (Pg) and interglandular (Ig) compartments from dorsal, ampullar and ventral prostate in P, A and AA animals, and the prostate zone in PP animals.
At the most extreme end of the behavioral spectrum of botryllid allorecognition, ampullar fusion (the complete membrane fusion of the vascular systems of opposing colonies and subsequent exchange of blood cells between the two colonies), has been described in Botryllus scalaris (Saito and Watanabe 1982) and is also thought to be the allorecognition behavior of B.
This ability is assessed using cut colony assays where the outer ampullar regions of two colonies are cut away and the internal areas are juxtaposed on a slide.
Then, within about 12 h of the contact hemocytes infiltrated the tunic from the ampullar
tips at the contact area [ILLUSTRATION FOR FIGURE 6A OMITTED].
This suggests that once donor cells have crossed the ampullar
barriers, they are able to survive and proliferate in the recipient colony, and are not being eliminated by an Fu/HC-based, or any other, allorecognition system.
Table I Hemoblast cell-specific immunoreactivity using anti-FGF2 in Molgula pacifica juveniles Cell type(*) and staining(**) Stage Antibody (Day) me tu ae hb ccm FGF2 2 - - - - - 3 - - - (+) - 4 - - - (++) - 5 - - - (+++) - EGF 2 - - - - - 5 - - - - - * Me, mantle epidermis; tu, tunic; ae, ampullar
epidermis; hb, hemoblast cells; ccm, central cell mass.
On the other hand, the ampullar
epithelia or some kinds of blood cells may also be alloreactive in B.
Two bands of tissue, which Smith (1950b) named 'seams' (see also Cobb, 1967; Cobb and Laverack, 1967), run dorsoventrally in the ampullar
neck: one seam occupies a medial position on the portion of the neck closest to the central axis of the arm, and the other is located laterally on the opposite side of the ampullar
neck [ILLUSTRATION FOR FIGURE 5 OMITTED].
Blood cells were evident within each ampullar