Antigenic profile, isolation and characterization of whole body extract of Paramphistomum gracile.

An antigenic component of adult Paramphistomum gracile was characterized by means of indirect enzyme-linked immunosorbent assay (indirect ELISA), sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting using sera from cattle naturally infected with P. gracile, Eurytrema pancreaticum, Fasciola gigantica, Moniezia benedeni, strongylids, Trichuris sp. and Strongyloides sp. The whole body (WB) extracts of P. gracile were fractionated by gel filtration chromatography in a Sephadex G-200 column. It was found that the WB extract fractions, F1-F3 were highly antigenic, F5 was moderately antigenic and F4 was poorly antigenic. For SDS-PAGE and immunoblotting, the antigenic molecules of WB extract and all five fractions were mostly at molecular weights (MW) ranging from 12 to 150 kDa. One antigenic protein of 16 kDa detected in WB extract and F1-F3 was found to give a consistent reaction with sera from infected cattle. The antigenicity of the purified 16 kDa protein was confirmed by immunoblotting and indirect ELISA using a pool of sera and individual serum samples from infected cattle (at 1 : 78 125 dilution) and hyperimmunized rabbit (at 1 : 390 625 dilution). This finding suggests that the 16 kDa protein may be a potential antigen for the immunodiagnosis of cattle paramphistomosis caused by P. gracile.

Relationship between chromatin condensation, DNA integrity and quality of ejaculated spermatozoa from infertile men.

Normal chromatin condensation is important for sperm fertilising ability. However, routine semen analysis does not identify defects in sperm chromatin structure. This study aimed to investigate the condensation of chromatin and DNA integrity in spermatozoa of infertile men and deduce the relationship with sperm quality, as measured by conventional semen parameters. Semen analysis was carried out to assess sperm quality according to World Health Organization criteria. The remaining aliquot of each sample was processed for transmission electron microscopy, chromomycin A3 (CMA3) and terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assays. The ultrastructural analysis of spermatozoa from infertile men showed heterogeneity in sperm nuclear morphology. Some spermatozoa displayed a round nucleus with incomplete chromatin condensation. Immunoreactivity with antitransitional protein and antiprotamine antibodies indicated nuclear maturation defects in the spermatozoa of infertile men. Spearman's correlation analysis indicated a positive correlation between the percentages of CMA3- and TUNEL-positive spermatozoa. In addition, these two parameters were negatively correlated with sperm concentration, motility and normal morphology. This study demonstrated that men with morphologically normal spermatozoa of <30% have greater degree of protamine deficiency and DNA damage than men with morphologically normal spermatozoa of >30%. Evaluation of chromatin integrity appears to be a useful tool for assessing male fertility.

The mechanism of formation of inhibitor-induced ribosome helices in Entamoeba invadens.

Helices andaggregates of helices (chromatoid bodies) composed of ribosomelike particles appear in cysts and slow-growing trophozoites of Entamoeba invadens. We found that similar helix aggregates were formed abundantly in actively growing E. invadens trophozoites treated with a variety of direct or indirect inhibitors of protein synthesis. The inhibitor-induced helices appeared cytochemically and ultrastructurally identical to those seen in cysts. Numerous single helices and small arrays occurred randomly distributed throughout the trophozoite cytoplasm within 15 min after treatment with NaF, which rapidly and completely stopped all nucleic acid and protein synthesis. Cycloheximide (CH), which inhibited protein synthesis as effectively a NaF, stimulated aggregate formation more slowly, and only after a delay of 30-60 min. CH temporarily blocked NaF-stimulated aggregated formation. Aggregation was slowest with actinomycin-D, which strongly inhibited RNA synthesis but depressed protein synthesis only slowly. These results suggested that release of ribosomes from mRNA was required for aggregation. Inhibition by CH was reversible, and aggregates disappeared from CH-treated amebas shortly after they were transferred to inhibitor-free frowth medium. There was no evidence that helices assembled about a structural organizer within the cell or that the process involved metabloc activity. It was concluded that the inhibitor-induced helices were composed of mature, normally functional ribosomes and that helix formation was a spontaneous and reversible consequence of the accumulation withing the cell of free monosomes (or subunits) which were prevented from binding to mRNA.

Increase of glutamate/N-methyl-D-aspartate receptor immunodensity in the dentate gyrus of rats following pseudoephedrine administration.

Pseudoephedrine is a sympathomimetic drug in which its structure is similar to amphetamine. Although pseudoephedrine is not as potent as amphetamine, it has been reported that the actions of pseudoephedrine on the central nervous system via dopamine release resemble to amphetamine. Changes of dopamine function can induce malfunction of glutamatergic system because there are well-documented interactions between glutamate/N-methyl-D-aspartate (NMDA) receptors and dopaminergic system. Therefore, the aim of this study was to investigate the effects of acute and chronic pseudoephedrine administration on NMDA receptors in hippocampal formation. Immunohistochemistry was used to determine the alteration of NMDA receptor density in rat hippocampus and dentate gyrus following acute and chronic pseudoephedrine administration. The density of NMDA receptors was increased significantly (p<0.005) in the dentate gyrus of animals treated with pseudoephedrine chronically when compared with the acute and control groups. Similarly, the density of NMDA receptors in an acute group was also higher than the control group (p<0.01). These results indicate that pseudoephedrine could induce an increase of NMDA receptors in the dentate gyrus. This might be a compensatory effect of NMDA receptor in response to the degeneration or loss of glutamatergic neurons.

Immunolocalization of cytoskeletal components in the tegument of the 3-week-old juvenile and adult Fasciola gigantica.

Components of three cytoskeletal elements, namely, microtubule, intermediate and actin filaments have been localised in the tegument of the 3-week-old juvenile and adult Fasciola gigantica by means of immunofluorescence and immunoperoxidase techniques, using mouse monoclonal anti-alpha-tubulin, anti-cytokeratin antibodies and biotinylated-phalloidin, respectively. The immunostaining with the above probes were also performed in adult Schistosoma mansoni for comparison. The presence of tubulin, indicative of microtubules, was demonstrated in the tegumental cell bodies, their cytoplasmic processes, and the basal layer of the tegumental syncytium of F. gigantica. While in S. mansoni, tubulin appeared as vertical lines stretching across the whole thickness of the syncytium. Cytokeratin, representing one type of intermediate filaments, was detected in the tegumental cell bodies, their cytoplasmic processes, tegumental syncytium and spines of F. gigantica. In contrast, cytokeratin was evident only in the syncytium of S. mansoni, but not in the spines. Phalloidin, which could bind to actin, a subunit of microfilament, was detected in the tegumental cell bodies, their processes, and the microtrabecular network which form the scaffold of the tegumental syncytium of F. gigantica. In S. mansoni, actin was localized in similar tissues except the syncytium was not stained while spines exhibited intense staining. In F. gigantica, the presence of microtubules and actin filaments in the tegumental cells, their processes and in the syncytium could mediate the movement of secretory granules from the cell bodies towards the basal as well as the apical layer of the tegument. Cytokeratin filaments may serve to reinforce the integrity of the tegumental syncytium as well as the spines.

Egg-laying-hormone immunoreactivity in the neural ganglia and ovary of Haliotis asinina Linnaeus.

Immunoreactivity against the abalone egg-laying hormone (aELH) was detected in the fine granules of type 1 and 2 neurosecretory (NS) cells, neurites in the neuropil, and blood sinuses in the connective tissue sheath of the cerebral, pleuropedal, and visceral ganglia of the tropical abalone, Haliotis asinina Linnaeus. The number of positive NS cells, and the intensity of staining in the ganglia, varied and might be related to the stage of ovarian cycle. At any stage, positive cells were most numerous in the pleuropedal, and least numerous in the visceral ganglion. In addition, several cells of the statocyst and associated nerves also exhibited the immunoreactivity. In the ovary, the most intense reactivity was detected in the follicular and granular cells adjacent to mature oocytes, in the trabeculae and the ovarian capsule. The cytoplasm of mature oocytes was also moderately stained. The results indicate that the cerebral, pleuropedal, and visceral ganglia are the main sites of aELH-producing cells. The ovary may also produce aELH locally.

Opisthorchis viverrini: the tegumental cytoskeleton.

The tegumental cytoskeleton of Opisthorchis viverrini was observed using both conventional transmission electron microscopy and Triton X-100 extraction. The cytoskeletal elements of the newly excysted juveniles, first-week and adult stages are composed of 2 components: firstly, the network of knobbed fibres designated as microtrabeculae which form the principal scaffold of the cytoplasm; and secondly, the microtubules. The microtrabeculae are more densely packed in the newly excysted juveniles and become less densely packed later in the first-week and adult stages. Generally, their compactness in the tegument of each stage is higher in the apical and middle zones than in the basal zone. The results from extraction by Triton X-100 suggest that the microtrabeculae may be composed, at the primary level, of thin and straight fibres, partly coiled up to form knobbed fibres, which are highly cross-linked at the secondary level. At the tertiary level, these knobbed fibres may be coiled up further and form closely aggregated globules that appear as dense dots in cross-section. Most microtubules are confined within the tegumental cells' processes and splay out in the basal zone of the tegument. In addition, there are condensed laminae of cytoplasm with intermittent dense plaques underlining the outer membrane, with microtrabecular fibres inserting into them. This organization may help to stabilize the outer membrane and preserve the surface contour. Along the inner membrane of the tegument, there are hemidesmosomes distributed at regular intervals, with fine fibres radiating out from them to intertwine with the microtrabecular network, which may help to anchor the tegument to the basal lamina. Spines, which exist mainly in the newly excysted juveniles, appear as a crystalline lattice structure whose bases are firmly fused to the inner membrane.

Opisthorchis viverrini: changes of the tegumental surface in newly excysted juvenile, first-week and adult flukes.

The tegumental surface of the newly excysted juvenile, first-week and adult stages of a human liver fluke, Opisthorchis viverrini, was studied by scanning electron microscopy. The surface of the newly excysted juvenile is characterized by circumferentially arranged ridges alternated with troughs which bear rows of spines encircling the body. These spines are characterized by the shapes of their edges: the first type with serrated edge appears on the anterior part, and the second type with single sharp edge appears on the middle part. There are no spines on the posterior part of the body. Three types of presumed sensory papillae are present: type A is a single small cone-shaped ciliated papilla; type B is a group of ciliated papillae on a common dome-shaped base; and type C is a large papilla with nonciliated bulb. Type A papillae are scattered evenly on the surface but are more concentrated around the oral and ventral suckers, as well as the excretory pore. Pairs of both type A and B papillae are located in rows along the lateral surfaces of the body. Type C papillae are located solely on the lip of the ventral sucker. In the first-week fluke the tegumental surface appears corrugated and covered with short developing microvilli, and spines are mostly lost. In the fully-grown adult fluke the surface appears highly corrugated with wave-like folds encircling the body which are covered in turn with closely packed stubby microvilli. Microvilli are more numerous and are taller on the ventral than on the dorsal surface. Among microvilli on the surface of both older stages three types of sensory papillae as in the newly excysted juvenile were observed, but they are of larger sizes. The number of type A papilla increases whereas that of type B papilla decreases during maturation. The distribution of papillae in both stages is similar to the newly excysted stage.

Opisthorchis viverrini: ultrastructure of the tegument of the first-week juveniles and adult flukes.

The tegument of one-week-old and adult flukes of Opisthorchis viverrini were studied by transmission electron microscopy. The tegument of both stages is composed of a syncytium formed by processes of the tegumental cells lying underneath the outer-circular and the inner-longitudinal muscle layers. The tegument is bounded by trilaminate outer and inner membranes; the former is coated with a thin glycocalyx, while the latter has short basal infoldings. There are 4 forms of tegumental granules, namely dense spherical, dense discoid, light spherical and light discoid granules. Dense spherical and dense discoid granules have similar dense homogeneous and highly electron-dense matrices; thus, they may represent different planes of sections of biconcave granules, and may contribute their content to the formation of the outer membrane and the glycocalyx. Light spherical and light discoid granules may be another type of granule whose filamentous content may contribute to the formation of the microtrabecular network in the tegument. Microvilli start to develop in one-week-old juveniles and become fully developed in adult stages. The size, number and cristae of the mitochondria become increasingly more numerous along with the development of microvilli; in the first-week juveniles most mitochondria are located in the basal portion of the tegument while in adults most lie within microvilli underneath the outer membrane. The tegumental cell is irregular in shape and contains a nucleus with a prominent nucleus, abundant rough endoplasmic reticulum, well developed Golgi complexes, ribosomes, mitochondria and numerous tegumental granules.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of implantation of hamster embryos by lectins.

In order to test their effects on implantation, lectins (Con A and WGA) were infused into one horn of the uterus of each female hamster aged between 10 and 14 weeks at day 3 of pregnancy (D3). Con A was given to three groups of 10 animals each at dosages of 100, 200 and 400 micrograms/10 microliter normal saline (NS)/animal, and WGA to four groups of animals at dosages of 20, 50, 100 and 200/10 microliter NS/animal. Control groups consisted of untreated animals and animals treated with saline. On D8, laparotomy was performed and the number of fetuses were counted. In untreated and NS-treated groups the number of fetuses were 6.9 and 6.8 per horn, which were not significantly different. In Con A-treated groups, at dosages of 100, 200 and 400 micrograms the number of fetuses were 2.2, 2.5 and 2.1 per horn, respectively. By contrast, in WGA-treated groups no implantation was detected, except at the dosage of 20 micrograms, in which 1.1 fetuses per horn was observed. To study the mechanism of inhibition, another three groups of animals were similarly treated with NS, 100 micrograms Con A and 50 micrograms WGA/10 microliter NS/animal, respectively. On D4 at 1300-1400 h, uterine lumens were flushed to collect unimplanted blastocysts. No blastocyst was found in NS- and Con A-treated groups, whereas 6.2 blastocysts with complete zona pellucida were collected per horn in WGA-treated group. Histologically, Con A caused vacuolization in epithelium and edema in the stromal layer of endometrium. However, such changes were not observed in WGA-treated uteri.

Molecular cloning and characterization of cathepsin L encoding genes from Fasciola gigantica.

In this study cDNAs encoding cathepsin L-like proteins of Fasciola gigantica were cloned by the reverse transcription polymerase chain reaction method (RT-PCR) from total RNA of adult specimens. DNA sequence analyses revealed that six different cathepsin L cDNA fragments were isolated, which have DNA sequence identities of 87-99% towards the homologous genes from F. hepatica. Gene expression was studied at the RNA level by Northern and RNA in situ hybridizations. Northern analysis showed the cathepsin L genes to be strongly expressed in adult parasites as a group of 1050 nt sized RNAs. RNA in situ hybridization localized cathepsin L RNA to the cecal epithelial cells. Southern hybridization was used to determine the number of cathepsin L genes and indicated the presence of a family of closely related cathepsin L genes in the genome of F. gigantica.

Production and characterization of a monoclonal antibody against recombinant fatty acid binding protein of Fasciola gigantica.

In Fasciola parasites fatty acid binding proteins (FABPs) are the carrier proteins that help in the uptake of fatty acids from the hosts' fluids. Attempts have been made to utilize both native and recombinant FABP (rFABP) for immunodiagnosis and vaccine development for fasciolosis. In this study, we have produced a number of monoclonal antibodies (MoAbs) against rFABP of Fasciola gigantica. These MoAbs were initially screened against rFABP by ELISA and then tested for their specificities by immunoblotting. Five stable clones were selected and characterized further: four of them were of the isotype IgG(1) while one clone was IgG(2a). All the MoAbs reacted with rFABP which has a molecular weight (MW) of 20 kD and with at least two isoforms of native proteins at MW 14.5 kD that were present in the tegumental antigen (TA) and crude worm extracts, and the excretion-secretion materials. Immunoperoxidase staining of frozen sections of adult parasites by using these MoAbs as primary antibodies indicated that FABP were present in high concentration in the parenchymal cells and reproductive tissues, in low concentration in the tegument and caecal epithelium. All MoAbs cross-reacted with a 14.5 kD antigen present in the whole body (WB) extract of Schistosoma mansoni, while no cross-reactivities were detected with antigens from Eurytrema pancreaticum and Paramphistomum spp.

Opisthorchis viverrini: effect of praziquantel on the adult tegument.

Ultrastructural changes of the tegument of adult liver flukes, Opisthorchis viverrini, after in vitro incubation in Minimal Essential Medium containing 0, 0.1, 1.0 and 10.0 micrograms/ml of anthelminthic praziquantel for 5, 15, 30, 45 and 60 minutes were investigated by scanning (SEM) and transmission (TEM) electron microscopy. SEM observations showed that the surface damage was composed of blebbing due to the swelling of microvilli, followed later by the disruption of these structures to form lesions that caused the erosion and desquamation of the surface. Sensory papillae, by contrast, appeared relatively unaffected. The surface changes could be observed at all doses but the extent of damage increased with increasing duration of incubation and concentration of the drug. The ventral as well as the dorsal surfaces exhibited similar change, whereas the anterior part tended to be damaged less than the posterior part. Under TEM observations, the earliest sign of changes was the depolymerization of the microtrabecular network in scattered foci, which resulted in the formation of non-membrane-bound vacuoles under microvilli. The basal infoldings also became dilated, and some turned into membrane-bound vacuoles in the basal zone. Subsequently, microvilli became enlarged, and eventually formed blebs that later rupture to form lesion spots as observed in the SEM. Finally, the microtrabecular network in all regions broke down, creating vacuoles of various sizes throughout the tegument, leading to its total disintegration and detachment. The sequence of morphological changes was generally similar at all doses; however, the changes occurred faster at the higher doses and the longer incubation times. In addition, at the longer durations myofilaments in most muscle cells also became depolymerized, while microtubules were unchanged by the drug. Therefore, it is possible that praziquantel, through its induction of Ca2+ influx, causes depolymerization of the microtrabecular network that leads to the vacuolization, swelling, blebbing, and eventually the disruption and detachment of the tegument, and the breakdown of myofilaments in the muscle cells.

Opisthorchis viverrini: the effects of colchicine and cytochalasin B on the adult tegument.

The roles of the tegumental cytoskeleton were tested by treating adult flukes with colchicine and cytochalasin B. Following a short incubation period (10-20 minutes), colchicine disrupted microtubules in the tegumental cells' processes which, in turn, affected the transport of dense granules from the cells' soma to the tegument; as a result some of these granules were fused together to form membrane-bound vacuoles. In addition, at many spots microtrabeculae were also depolymerized, which resulted in the formation of non-membrane-bound vacuoles and the distension of microvilli to form blebs, some of which were disrupted. After prolonged incubation (120 minutes), general breakdown of the tegumental cytoskeleton occurred, and parts of it were sloughed off. In cytochalasin B treatment, the responses were similar to those of colchicine but with less severity. After a short incubation period (10-20 minutes), the microtrabeculae were depolymerized which led to the formation of non-membrane-bound vacuoles in the apical and middle zones of the tegument. Later, the tegumental microvilli were distended to form blebs but no evidence of tegumental sloughing occurred even in prolonged incubation. From these observations, it was concluded that microtubules played a role in the translocation of granules from the tegumental cells to the tegument which modulated the synthesis of membrane and glycocalyx, while microtrabeculae were involved in the maintenance of the structure and integrity of the tegument.

Monoclonal antibodies against Schistosoma mekongi surface tegumental antigens.

Monoclonal antibodies were produced from naturally infected BALB/c mice. Thirteen hybridomas which were found to produce monoclonal antibodies against surface tegumental antigens of Schistosoma mekongi by ELISA assay were used in this study. The antigen specificities of hybridomas reactive with surface tegumental antigens were characterized and localized by immunoblotting analysis and Avidin-Biotin method. Of the 13 hybridomas, only three produced monoclonal antibodies to the single epitopes in the surface tegumental antigens. These epitopes (125 kDa, 97 kDa and 38 kDa) have been found to be the major antigenic components of the surface tegument of S. mekongi. The 38 kDa antigen was found to associate with the surface tegumental layers, the muscular layers lying just beneath the tegument, as well as in the gut surface. The 97 and 125 kDa antigens were detectable only in the surface tegumental area. The biochemical identity of these proteins or glycoproteins is unknown. However, these antigens have also been described in S. japonicum and S. mansoni.

Development and characterization of monoclonal antibodies against excretory-secretory antigens of Fasciola gigantica.

Monoclonal antibodies (MAbs) directed against Fasciola gigantica excretory-secretory (ES) antigens were developed from BALB/c mice. Four were selected for further study, from the panel of hybridomas. The antigen specificities of these MAbs were characterized and localized by enzyme-linked immunoeletrotransfer blot (EITB) and immunoperoxidase technique. The target epitopes of these MAbs are 66 kDa protein (MAb 2D10), 66 and 27-26 kDa proteins (MAbs 5D10 and 4F5) and 27-26 kDa protein (MAb 2D9). MAb 2D9 reacted to the antigenic components of the luminal content and epithelial cell lining the cecum, whereas MAb 2D10 reacted specifically to the antigens of the tegument and surface membrane. It was found that all MAbs cross-reacted to various degrees with the antigens extracted from Schistosoma mansoni, S. mekongi, S. spindale and Paramphistomum spp. However, when MAbs were diluted to 1:100 or 1:400 significant reduction of their cross-reactivities was observed.

Scanning electron microscopic study of microfilaria and the third stage larva of Wuchereria bancrofti.

The surface structures of microfilaria and of the third stage larva of Wuchereria bancrofti were studied by scanning electron microscopy. Distinct features were observed that could be used for differentiating species of this parasite. Specifically, the sheath of microfilariae of W. bancrofti projected beyond the head. The head region of the microfilaria was composed of a cephalic cap with hook, mouth and amphidial opening, and its cuticle showed annulation. Spines were absent at the first transverse annulation, and the tail end showed a slight constriction. In the infective stage larva, characters which are used for differentiating species, such as the two bubble-like ventro-lateral papillae and one dorso-terminal papilla were rather similar to each other in size, but the grooves seen around the base were absent. A previously unreported feature of the third stage larva of W. bancrofti that was discovered in this study is a papilliform process on the left side of the posterior region, between the anus and the tail end.

Alterations of the surface tegument of Opisthorchis viverrini exposed to praziquantel in vitro and in vivo.

The in vitro and in vivo effects of praziquantel on the ultrastructural surface of Opisthorchis viverrini were investigated using scanning electronmicroscopy. For the in vitro study, adult flukes were collected from experimentally infected hamsters, and were incubated for various time intervals at 37 degrees C in Earle's basal medium containing praziquantel at final concentrations of 0.01-100 micrograms/ml. For the in vivo study, flukes were collected from the biliary system of experimentally infected hamsters that had been treated 4 hours previously with 350 mg of praziquantel per kg body weight (mg/kg). Flukes were also obtained from the feces of a patient with opisthorchiasis who had been given praziquantel once at a dose of 40 mg/kg 4-6 hours previously and from the bile of a patient at the time of operation 24 hours after praziquantel treatment. Scanning electronmicroscopic analyses of the surface teguments of flukes exposed to praziquantel either in vitro or in vivo showed similar changes. Tegumental bubbles of different sizes appeared on the surface; they later ruptured and resulted in the formation of crater-like lesions. These lesions might be so extensive as to result in the peeling of the entire areas. On occasions, "micronodules" appeared later in these areas and those at the periphery of the lesions; these micronodules may represent an attempt by the worm to regenerate new tegument. The possibility that these ultrastructural changes may represent a generalized response of the tegumental surface to an obnoxious agent was discussed.

Microtopography of the surface of adult Schistosoma japonicum-like (Malaysian) as observed by scanning electron microscopy.

The surface of adult Schistosoma japonicum-like (Malaysian) was studied by scanning electron microscopy. The basic pattern of surface microtopography is similar to other strains of S. japonicum as previously reported. However, among male member there are some unique differences in the types, number and distribution of surface papillae and morphology of ridges. Three kinds of papillae were observed: (1) the large fungiform papillae (3.5-4 micron in diameter, most without cilia) are more numerous than in other strains of S. japonicum, they concentrate on the lateral aspect of the anterior and middle parts close to the edge of the gynecophoral canal, and on the dorso-lateral aspect of the posterior part towards the tail tip; (2) the small hemispherical papillae (1.5-2 micron in diameter, all bearing cilia) are especially numerous in the suckers, the gynecophoral canal and parts of the tegument around the suckers and close to the tail tip; on the rest of the surface they are evenly distributed; (3) the cratered papillae (3-4 micron in diameter, about half having cilia) are more numerous than on other strains, they concentrate on the lateral aspect of the middle part and on the edges of the gynecophoral canal. The surface ridges (about 0.2-0.3 micron in width) are tall, highly branching and perforated; they are most developed in the middle part. Spines were observed only in the suckers and the gynecophoral canals. In contrast to the male, the female has numerous spines on all parts of the surface except the most anterior, where a large number of long cilia were observed. All three kinds of papillae were present; fungiform papillae are more numerous than in females of other strains; they concentrate on the latero-dorsal aspect of middle and posterior parts, and around the excretory pore. Ridges are much less developed than in the male and are prominent only in the middle part.