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An in vitro study has been carried out to monitor changes to the female reproductive system in adult triclabendazole (TCBZ)-resistant Fasciola hepatica following treatment with a commercial preparation of myrrh ("Mirazid"). Flukes were immersed for 6 h and 24 h in myrrh extract at a concentration of 200 µg/ml, then processed for histological and transmission electron microscope (TEM) examination of the uterus, Mehlis' gland, ovary and vitellaria. Egg production had become abnormal at 6 h post-treatment (pt), with the uterine lumen being filled with free vitelline cells and masses of shell protein material; few eggs were present. At 24 h pt, no eggs were present. Distinct changes to the ovary and Mehlis' gland were only observed after 24 h incubation in Mirazid. The ovary contained numbers of apoptotic oogonia and oocytes. In the Mehlis' gland, the S1 cells were disorganised and the processes from them were vacuolated, although the disruption was not significant. More severe changes were observed in the vitelline cells and follicles. After 6 h incubation in Mirazid, although the gross organisation of the vitelline follicles appeared to be normal, nuclear changes indicative of the early stages of apoptosis were observed in the stem cells and shell protein production by the mature cells had decreased. At 24 h pt, a distinct shift in cell population was evident, with the follicles containing mainly mature cells and spaces were present between the cells. The shell globule clusters in the mature cells were disorganised. In more severely-affected follicles, cells were seen to be breaking down, with karyolytic nuclei and disintegrating cytoplasm. Overall, the results have shown that exposure to Mirazid treatment had a severe impact on egg production by TCBZ-resistant flukes, an effect that was mediated by disruption of the vitelline cells and of the mechanism co-ordinating egg formation in the ootype.

The objectif in the present study is description of a new species of Sphincteristomum Oshmarin, Mamaev & Parukhin 1961, named Sphincteristomum mediterraneae, which is described in Oran bay, Algeria. It parasitizes the intestine of naturally infected Pagellus erythrinus, Teleostei, Sparidae. The Pagellus erythrinus is in important food fish in the Mediterranean. This genus belongs to the family Apocreadiidae, sub family Schistorchiinae, characterized by an obvious oral muscular sphincter, into a large oral sucker, a disc-shaped acetabulum under the intestinal bifurcation, an ocular pigment scattered in the forebody, a sequence ovary and two testes in tandem and a I-shaped excretory bladder. In the new species, the digestive apparatus displays a hexagonal peculiar aperture, followed by a longitudinal slit, a waved pharynx, two long and broad caeca, with a thick internal wall of endothelial cells. Each caecum has a sub terminal anus. The female genital apparatus displays a transversally elongated ovary, under the acetabulum. On the side of the ovary, there is a small Mehlis gland. Under the ovary, there are two transverse converging vitelloducts. Lateral and extracaecal vitelline follicles, are spread near the caeca. They converge in the hindbody. The relatively short uterus is preovarian, mainly. It contains few large yellow eggs. Its distal part is creased transversally, just before ending in genital atrium. The male genital apparatus shows two lobed heart-shaped testes, post ovarian, in tandem. From the anterior edge of each testis, two spermiducts climb up and converge into a naked, curved or sinuous seminal vesicle, followed by a short prostate surrounded by few prostatic cells, and a narrow ejaculatory duct, opening in genital atrium. The genital pore is close to the acetabulum and the intestinal bifurcation. No cirrus pouch. The excretory system shows a relatively short tubular I-shaped bladder, reaching the inferior level of the second testis. Two thin excretory arms are seen until the forebody of the worms. The terminal excretory pore is closed by a small sphincter. In the same P. eryrthrinus, immature worms devoid of genitalia, young worms with genitalia devoid of eggs and ovigerous worms, live together with senile specimens. These last ones show still, oral sucker, diffuse vitelline follicles and very small and scattered ocular pigment.

Lambs infected with the Cullompton triclabendazole (TCBZ)-susceptible isolate of Fasciola hepatica were treated with TCBZ at a dosage of 10 mg/kg at 16 weeks post-infection. Adult flukes were recovered from the liver at 3 h, 24 h, 48 h and 60 h post-treatment (pt). They were processed for histological analysis of the uterus, Mehlis’ gland, vitellaria, ovary and testis. At 3 h pt, the flukes were essentially similar to the controls and were producing normal eggs. Egg production had ceased by 24 h pt. At this time period, the cells of the Mehlis’ gland showed some evidence of vacuolation, but otherwise were relatively normal. A shift in the population of vitelline cells towards mature cells was observed at 24 h pt, and this trend continued at later time-periods. It was accompanied by a breakdown of the cells and the presence of apoptotic bodies. Marked changes to the ovary were first noted at 48 h pt, as evidenced by vacuolation and the presence of apoptotic bodies. Some disruption to the testis was seen at 24 h pt, with a reduction in the population of spermatogenic cells, the appearance of apoptotic bodies and some peripheral vacuolation of the tubules. These abnormalities increased in severity with longer time periods pt. The results bring forward the time-line of cessation of egg production by 24 h, demonstrating that this process is affected very rapidly pt.

Eight indoor-reared cross-bred sheep with no prior exposure to Fasciola hepatica were infected by oral gavage with 200 metacercarial cysts of the triclabendazole (TCBZ)-susceptible Cullompton isolate of F. hepatica. Twelve weeks after infection, sheep were treated with 10 mg/kg triclabendazole. Two sheep were euthanised per time period; at 48 h, 72 h and 96 h post-treatment (pt). Two untreated control sheep were euthanised at 96 h pt. Flukes were recovered from the liver and, if present, from the gall bladder of the sheep. They were processed for whole mount analysis, histology and transmission electron microscopy of the female reproductive system; specifically, the uterus, vitelline follicles, Mehlis’ gland and ovary. Over the 4-day post-treatment period, there was a progressive reduction in the number of oogonia and oocytes in the ovary and evidence of apoptosis. Vacuolation and a decrease in the number of Mehlis’ gland cells were observed from 48 h pt onwards and disruption of the normal role of the gland in egg formation was evident. The vitelline follicles showed a gradual decrease in size and became vacuolated; the population structure in each follicle changed to be one consisting mainly of mature cells and the production of shell protein material declined. The follicle became disorganised as the cells broke down and released their contents into the lumen of the follicle. While the uterus appeared to contain eggs at 48 h pt in whole-mount specimens, no properly-formed eggs were observed in histological sections. By 96 h pt, the uterus was completely devoid of eggs. Overall, egg production was seen to be severely affected by TCBZ treatment and flukes were incapable of producing normal eggs within 2 days of treatment. The implications of this in terms of the epidemiology of the disease are discussed.

The ‘secretory pathway’ of the Mehlis' gland secretion as well as the maturation of the secretory granules are described. The secretions produced by the Mehlis' gland and the distal ootype in Schistosoma mansoni were identified as neutral glycoproteins. They were both periodate reactive, stained with phosphotungstic acid at low pH, and sensitive to the proteolytic action of papain. The secretions did not strain with both the low-iron diamine and the high-iron diamine methods for the presence of acidic glycoconjugates, and they did not contain a detectable level of sulphydryl groups. The possible role of the secretion from the Mehlis' gland in egg-shell formation is discussed.

The ancyrocephaline monogenean gill parasite Cichlidogyrus halli typicus has a short oviduct/ovo-vitelline duct separated from the germarium and from the ootype by sphincter muscles. The chamber so-formed contains spermatozoa, the axonemal ends of which appear to be attached in an intimate way between lamellated extensions of the chamber lining. This arrangement may facilitate fertilization by retaining an oocyte temporarily in close contact with the free nucleated ends of the spermatozoa, i.e. the short oviduct/ovo-vitelline duct may serve as a fertilization chamber. There are two distinct types of Mehlis' gland opening at the base of the ootype and the latter has a cellular, non-secretory lining which is not penetrated by gland ducts.

Mehlis' gland of a digenetic trematode, Paragonimus ohirai, is composed of two types of secretory cells, DB and CB. The less abundant type (DB) produces dense bodies, with the cytoplasm characterized by greatly distended cisternae of rough endoplasmic reticulum. The other type (CB) synthesizes clear, vesicular bodies. Its cytoplasm contains numerous mitochondria, rough endoplasmic reticulum with narrow cisternae, and abundant Golgi complexes. Processes of the two cell types converge on the ootype-proximal uterine wall, pass through the epithelium, and finally open into the lumen. These proximal processes contain longitudinally arranged microtubules whose luminal ends are anchored to the epithelium by ring-form septate desmosomes. According to the distribution of the two types of processes, three different zones (DB, mixed, and CB) can be recognized within the epithelia. As the CB processes enter the lumen predominantly beyond the uterine valve region, this cell may produce secretions required for egg shell maturation or hardening. The role of DB cells (which enter the lumen more commonly in the ootype near the oviduct) remains unknown.

Mehlis' gland of both Diplozoon paradoxum and Calicotyle kroyeri is composed of two cell types that taper to form ducts opening into the lumen of the ootype. The cells are invested with fibrous interstitial material and form a close structural relationship with surrounding parenchyma. The most prevalent cell type, the S 1 cell, is characterized by an extensive GER with narrow cisternae containing a finely granular material, and numerous Golgi stacks involved in the formation of multi-vesicular secretory bodies. In the S 2 cells the GER cisternae are greatly distended with a finely filamentous material and the Golgi give rise to dense secretory bodies with a packed fibrous appearance. There are species differences in the fine structure of the secretory bodies and these may reflect differences in the chemical composition of the glands. The ducts of the glands are lined with microtubules and are anchored to the ootype epithelium by septate desmosomes. They convey the secretory products to the ootype where they are released, apparently by exocytosis involving membrane fusion, into the lumen. The ootype is lined by a highly folded cellular epithelium which in D. paradoxum is ciliated. The cells contain profiles of GER and Golgi complexes and produce a third type of secretion which is also discharged into the ootype lumen.

The female reproductive organs (ovary, vitellaria, and Mehlis' gland) of the digenetic trematode Halipegus eccentricus were studied by transmission electron microscopy. Oocytes entered diplotene while in the ovary and produced cortical granules and lipid bodies. Vitelline cells produced large amounts of eggshell protein but no yolk bodies. Two types of Mehlis' gland secretory cells were present, distinguishable by the morphology of their rough endoplasmic reticulum, Golgi bodies, and secretory bodies, and by the persistence of recognizable secretory material within the ootype lumen after exocytosis. In an attempt to standardize the nomenclature regarding the cell types of the Mehlis' gland, a classification that takes into account these four criteria is proposed. Two basic types of Golgi body organization were noted for the cells of the female reproductive system: a stack of flattened cisternae (Mehlis' gland alpha cells) and spherical Golgi bodies with vesicular cisternae (oocytes, vitelline cells, and Mehlis' gland beta cells).

The metacercarial stage of Gymnophalloides tokiensis has a mid-ventral pit which was mistaken in the original description for a wide genital pore. The genital pore is small, on the anterior edge of the ventral sucker, and not surrounded by prominent muscle fibers. Other corrections of the original description include paired, compact vitellaria (referred to as Mehlis gland), a bipartite (not globular) seminal vesicle, and an ovary smaller than the testes; no eye spots or a seminal receptacle are present.Yamaguti's (1971) synonymy of Lacunovermis Ching, 1965 with Gymnophalloides is rejected because of the differences in the location and type of genital pore. In contrast to G. tokiensis, both L. conspicuus and L. macomae (Lebour, 1908) Loos-Frank, 1970 have a wide genital pore that opens some distance from the ventral sucker and both ventral pit and genital pore are surrounded by strong muscle fibers.Two of Yamaguti's (1971) footnotes about gymnophallid trematodes are corrected. In my 1965 paper, I did not synonymize Gymnophalloides with Meiogymnophallus but replaced Gymnophalloides as emended by James (1964) with the name Meiogymnophallus. I did not synonymize Gymnophallus oidemiae, now M. minutus (Cobbold, 1859) Bowers and James, 1967, with G. somateriae but regard them as distinct species.

The oogenotop was studied using certain histochemical tests and the contributions of the various parts to the egg were noted. The Mehlis gland and the uterine epithelium make large contributions to the egg. Both the inner and outer envelopes are of reduced importance. A photographic record of oogenesis is presented showing it follows previous descriptions for the Cestoda. The first cleavage is unequal. Shell granules from the oocyte are carried to the macromeres where they are used in the formation of the outer capsule. Hatching is standard for eggs with a membraneous inner capsule. Most infections are characterized by one female and one male worm. Microsporidians reduce the number of sperm produced and probably limit the production of oncospheres.

Amphilina bipunctata Riser, 1948 were collected from the white sturgeon Acipenser transmontanus from the Columbia River, USA. The morphology and histochemistry of the oogenotop of Amphilina as they pertain to egg formation are described. The vitelline gland granules secrete the main part of the egg shell. These shell granules are positive for basic proteins, SS groups, and there is a weak reaction for phenolase. The Mehlis gland granules are positive for PAS. The first-formed egg shell is positive for basic proteins and it is weakly positive for phenolase. These egg shells are negative for SS groups and PAS. Conjectures concerning the significance of these data are made.

1. 1. When exposed in vitro to C 14 proline male schistosoma become much more heavily than do females. 2. 2. The areas of concentration in the male are the integument and sub-integument, the paraoesophageal region, the gut and the testes. 3. 3. In the female local accumulation in the posterior ovary and, to a lesser extent, in the mehlis gland was noted. 4. 4. The vitelline gland and duct fail to tag heavily on exposure; the female gut also shows minimal proline uptake. 5. 5. Proline may play a special metabolic role in either the paraoesophageal musculature or in the nearby neural ganglionic ring. 6. 6. Speculations concerning functional implications of these findings are given.

Histochemische Untersuchungen der Mehlischen Druse vonFasciola hepatica erweisen deren Phospholipidabsonderung. Es wird auf die Moglichkeit einer engen Bezichung des Phospholipids zu Lezithin und seine enzymatische Aktivierung zur Herauslosung von Eischalenprokursoren hingewiesen.

The cells of Mehlis's gland in the liver fluke (Fasciola hepatica L.) have been studied with light and electron microscopy. The gland contained large cells in the periphery and small cells in the centre. The large cells presented morphological features characteristic of secretory cells, viz. large nucleoli, cytoplasmic basophilia, a well developed endoplasmic reticulum, abundant ribosomes, and secretory granules in different stages of development. The mitochondria were moderately frequent. Several small groups of vesicles and membraneous lamellae reminiscent of Golgi complexes occurred randomly in the cytoplasm. These structures were associated with mitochondria and secretory granules. Evidence of alterations and conversion into a cell debris was observed, and a process of holocrine secretion was suggested.

reproductive system of the trematodes and cestodes, and consists of a series of glandular structures surrounding the ootype, the tube connecting the oviduct to the uterus. These glands vary in number and arrangement in the different groups and species. This gland is particularly well developed in the liver fluke, F. hepatica, where its huge size has made it difficult to appreciate its relationship with the complicated system of ducts embedded in it. In consequence there has been a conflict in interpretation (Stephenson, 1947, Yosufzai, 1953) and the purpose of this paper has been to attempt some clarification.