Penetration gland

Mikes, L. and Man, P. (2003) Purification and characterization of a saccharide-binding protein from penetration glands of Diplostomum pseudospathaceum - a bifunctional molecule with cysteine protease activity. Parasitology 12 7, 69-77. 

Test Indicates presence of Variety" Shell Cytoplasmic layer Inner envelope Gelatinous layer Embryophore Penetration gland Hooks... 

The process of hatching in the Cyclophyllidea, which results in the release of the oncosphere, has been discussed in Chapter 7. The basic structure of a mature oncosphere (Fig. 8.16), which will not be discussed in detail here, does not vary substantially between species. It is composed essentially of (a) a thin covering epithelium with cytoplasmic extensions, (b) an additional complex system of muscles operating the three pairs of hooks, (c) a pair of large penetration glands, (d) a small core of germinative cells from which the next larval stage develops and (e) a primitive nervous system. 

Although secretions from the (so-called) penetration glands undoubtedly play a role in penetration, their nature and function are largely unknown. The glands have been particularly studied in H. diminuta and H. nana (205, 888, 889). In most species, glands have been described as syncytial (Fig. 8.16) or multicellular, but in H. nana they appear to be unicellular (205). One or two pairs of ducts may be present and these are supported by microtubules. Secretion has been described as being holocrine in some species (as in trematode miracidia and cercariae) but apocrine and merocrine secretory mechanisms have also been proposed for others (205, 242, 443). 

Fig. 8.18. Hymenolepis diminuta rate of secretion of neutral red-positive material from the penetration glands of newly hatched hexacanths in Tyrode s solution alone (—) and in Tyrode s + adult Tenebrio molitor midgut extract (—). (Modified from Lethbridge Gijsbers, 1974.)...

Hymenolepis nana the fine structure of the penetration gland and nerve cells within the oncosphere. Parasitology, 82 445-58. 

Mackinnon, B. M., Jarecka, L. Burt, M. D. B. (1985). Ultrastructure of the tegument and penetration glands of developing procercoids of Haplobothrium globuliforme Cooper, 1914 (Cestoda Haplobothrioidea). Canadian Journal of Zoology, 63 1470-7. 

Penetration glands of oncospheres of Hymenolepis diminuta (Cestoda). Histochemical studies. Bulletin de I Academie Polonaise des Sciences, Class II, 25 619-22. 

Rotating parts of bearings, shaft penetrations, gland seals etc. may become sources of ignition if not lubricated sufficiently. ... 

---