Ultrastructure and cytochemistry of the tegument ofOrthocoelium scoliocoeliumandParamphistomum cervi(Trematoda: Digenea)

Abstract

The tegument ofOrthocoelium scoliocoeliumandParamphistomum cerviwas examined using histochemical techniques and electron microscopy. On the basis of the distribution of acid and alkaline phosphatase (E.C. 3.1.3.2, E.C. 3.1.3.1), non-specific esterase (E.C. 3.1.1.1), cholinesterase (E.C. 3.1.1.7) and succinate dehydrogenase (E.C. 1.3.99.1) at light microscope level two distinct regions were recognized, an outer and an inner zone. Electron microscopy revealed that the tegument comprises an outer surface syncytium underlain by a thick subsyncytial zone and musculature. Deeper still occur the nucleated “tegumental cells”. The latter are in cytoplasmic continuity with the surface syncytium via vacuolated cytoplasmic trabeculae which traverse the muscle layers and the subsyncytial zone. Three types of tegumental cells each lacking mitochondria were observed. The T1cells synthesize discoid and electron dense T1bodies while T2cells produce oval and electron lucent T2bodies. The third type of tegumental cells apparently produce no secretory bodies and may represent an embryonic cell type. The surface syncytium contains T1and T2secretory bodies and is bounded apically by a plasma membrane invested externally by a fuzzy and filamentous glycocalyx. The surface syncytium lacks mitochondria and is traversed by infoldings of the basal plasma membrane. Beneath the surface syncytium the subsyncytial zone is largely comprised of fibrous interstitial material. This zone, which is particularly thick in the amphistomes, is traversed by trabeculae and extensions of underlying parenchymal cells which usually contain mitochondria and lysosomes. The subsyncytial zone overlies numerous circular and longitudinal muscle fibres. The absence of mitochondria and enzymes associated with active transport suggests that the amphistome tegument may be mainly specialized for protection of the worm against mechanical and chemical conditions prevailing in the rumen. Active uptake of nutrients is probably not a primary function.

Gastrothylax crumenifer: Ultrastructure and histopathology study of in vitro trematodicidal action of Marattia fraxinea (Sm.)

“…The tegument of P. cervi comprises an outer surface syncytium underlined by a thick subsyncytial zone and musculature [70]. M. fraxinea Sm.…”

Ultrastructure of the tegument of Prosorhynchoides arcuatus (Linton, 1900) Bray, 1984 (Trematoda, Bucephalidae)

“…According to these authors, a greater amount of energy may be needed at the outer membrane and this energy is supported by mitochondria. Otherwise, in Orthocoelium scoliocoelium and Paramphistomum cervi (Sharma & Hanna, 1988), mitochondria are absent; thus large quantities of amino acids and other metabolites are not taken up across the tegument of the rumen amphistomes. According to Brennan et al (1991), the absence of mitochondria in Gastrodiscoides hominis would suggest that the tegument in this worm is also primarily protective in function with limited absorptive capacity.…”

Ultrastructure of the vitellarium in the digeneans Phyllodistomum angulatum (Plagiorchiida, Gorgoderidae) and Azygia lucii (Strigeida, Azygiidae)

“…The sequential cytodifferentiation of immature vitelline cells assumes the production and subsequent accumulation in their cytoplasm of several inclusions, including vitelline globules, lipid droplets and glycogen. It is apparent from previous descriptions of vitelline cells that a number of differences exist between the composition and amount of these inclusions in various digenean species (Tulloch and Shapiro 1957;Koulish 1969;Irwin and Threadgold 1970;Hanna 1976;Grant et al 1977;Irwin and Maguire 1979;Erasmus et al 1982;Fukuda et al 1983;Holy and Wittrock 1986;Fairweather et al 1988;Hendow and James 1989;Podvyaznaya 1990Podvyaznaya , 2003Sharma and Swarnakar 1992;Chaymardanov and Tanyüksel 1995;Świderski et al 2011).…”

“…From the available literature, we can assume that, as in P. angulatum, mature vitelline cells of the other gorgoderids Gorgoderina attenuata (see Koulish 1969) and G. vitelliloba (see Irwin and Maguire 1979) do not contain glycogen, as is the case for the vitelline cells of Paralecithodendrium (as Prosthodendrium) ascidia (Lecithodendriidae) (see Podvyaznaya 1990) and the related Gyrabascus (as Allassogonoporus) amphoraeformis (Gyrabascidae) (see Podvyaznaya 2003). The presence of small numbers of β-glycogen particles has been noted in the peripheral cytoplasm of mature vitelline cells of Maritrema feliui (see Świderski et al 2011), which is a member of the same superfamily as the latter two species, as has α-glycogen in the vitelline cells of Schistosoma mansoni (see Erasmus 1973), S. haematobium, S. japonicum, S. mattheei (see Erasmus et al 1982) and Orthocoelium scoliocoelium (Paramphistomidae) (see Sharma and Swarnakar 1992). Erasmus (1973) believed that such a difference in the amount of glycogen in various digenean species may be related to the retention of eggs within the host tissue for an extended period.…”

“…Ultrastructural studies on the vitellarium of the trematode subclass Digenea have been presented by Tulloch and Shapiro (1957), Björkman and Thorsell (1963), Burton (1963), Koulish (1969), Irwin and Threadgold (1970), Erasmus (1973), Hanna (1976), Grant et al (1977), Irwin and Maguire (1979), Erasmus et al (1982), Fukuda et al (1983), Holy and Wittrock (1986), Hendow and James (1989), Podvyaznaya (1990Podvyaznaya ( , 2003, Sharma and Swarnakar (1992), Chaymardanov and Tanyüksel (1995), Colhoun et al (1998), Meepool et al (2006), Sampour (2008) and Świderski et al (2011).…”