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.

Molecular and immunological characterization of encoding gene and 14-3-3 protein 1 in Fasciola gigantica

A cDNA encoding Fg14-3-3 protein 1 was cloned by immunoscreening of an adult-stage Fasciola gigantica cDNA library using a rabbit antiserum against tegumental antigens of the parasite. The protein has a deduced amino acid sequence of 252 residues and a calculated molecular weight of 28.7 kDa. It shows sequence identity values between 57.6 and 58.1% to the human 14-3-3 beta, zeta, theta, and eta proteins and is in a phylogenetic cluster with the 14-3-3 protein 1 of Schistosoma spp. Nucleic acid analyses indicate that the Fg14-3-3 protein 1 is encoded by a single copy gene and that this gene is expressed as a transcript of 1250 nucleotides. In adult and 4-week-old parasites the gene's transcriptional and translational products were localized in the gut epithelium, parenchyma, tegument cells, and in the reproductive organs. An antiserum against recombinant Fg14-3-3 protein 1 detected a slightly smaller 14-3-3 protein in the parasite's excretion/secretion material and showed cross-reactivity with 14-3-3 proteins in extracts of other trematodes and mouse. Antibodies against Fg14-3-3 protein were detected in the sera of rabbits as early as 2 weeks after infection with metacercariae of F. gigantica and the antibody titre increased continuously over a 10-week observation period.

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.

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.

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.

Fasciola gigantica: surface topography of the adult tegument

Adult Fasciola gigantica are leaf-shaped with tapered anterior and posterior ends and measure about 35 mm in length and 15 mm in width across the mid section. Under the scanning electron microscope its surface appears rough due to the presence of numerous spines and surface foldings. Both oral and ventral suckers have thick rims covered with transverse folds and appear spineless. On the anterior part of the ventral surface of the body, the spines are small and closely-spaced. Each spine has a serrated edge with 16 to 20 sharp points, and measures about 20 microm in width and 30 microm in height. In the mid-region the spines increase in size (up to 54 microm in width and 58 microm in height) and number, especially towards the lateral aspect of the body. Towards the posterior end the spines progressively decrease in both size and number. The tegumental surface between the spines appears highly corrugated with transverse folds alternating with grooves. At higher magnifications the surface of each fold is further increased with a meshwork of small ridges separated by variable-sized pits or slits. There are three types of sensory papillae on the surface. Types 1 and 2 are bulbous, measuring 4-6 microm in diameter at the base with nipple-like tips, and the type 2 also have short cilia. Type 3 papillae are also bulbous and of similar size but with a smooth surface. These sensory papillae usually occur in clusters, each having between 2 and 15 units depending on the region of the body. Clusters of papillae on the lateral aspect (usually types 1 and 2) and around the suckers (type 3) tend to be more numerous and larger in size. The dorsal side of the body exhibits similar surface features, but the spines and papillae appear less numerous and are smaller. Corrugation and invaginations of the surface are also less extensive than on the ventral side of the body.

Opisthorchis viverrini: ultrastructure and cytochemistry of the glycocalyx of the tegument

The ultrastructure and cytochemistry of the glycocalyx of the tegument of Opisthorchis viverrini during maturation from newly excysted juvenile to adult stages were investigated using colloidal iron, ruthenium red and lectin stainings. The results showed that the glycocalyx was intensely stained by the first two dyes, thus indicating the presence of relatively high amounts of negative charges. However, the thickness and intensity of the staining decreased during the fluke's maturation. Binding studies using lectin probes on the surface of adult parasites showed that binding sites for Canavalia ensiformis (Con A), Triticum vulgaris (WGA) and Ricinus communis I (RCA I) were present in relative large amounts on the glycocalyx of the adult tegument, whereas those for Dolichos biflorus (DBA) were relatively fewer in number, and those for Ulex europaeus I (UEA I) were absent. The binding patterns of Con A, WGA, RCA I and DBA were generally similar, and the reaction product was uniformly distributed over the dorsal and ventral surfaces of the parasite's body. These bindings, therefore, indicate the presence of D-mannose/D-glucose, N-acetyl-D-glucosamine/sialic acid, D-galactose and N-acetyl-D-galactosamine residues on the glycocalyx of the adult tegument.

Identification of circulating antibodies in fasciolosis and localization of 66 kDa antigenic target using monoclonal antibodies

We identified three specific circulating antibodies in serum of cattle naturally infected with Fasciola gigantica. Two of the antibodies were found to react specifically to 97 and 66 kDa antigenic molecules of adult worm tegumental membrane extract. The third antibody was identified by the reaction with 26-28 kDa molecule of the excretory/secretory antigens. Monoclonal antibody against 66 kDa protein was developed and used for localization of its antigenic target in adult worm frozen sections. The experiment demonstrated that 66 kDa protein is a component on the outer surface membrane and on the membrane lining of the caecal epithelial of adult worm. The 66 kDa antigen was considered as a promising candidate for immunodiagnosis and vaccine.

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.

Fasciola gigantica: studies of the tegument as a basis for the developments of immunodiagnosis and vaccine

The tegument of bile-dwelling Fasciola gigantica is the interfacing layer that helps the parasite to maintain its homeostasis, and evade the hostile environment, including the host's immune attacks. The tegument is a syncytial layer about 10 mm thick, that is formed by the fusion of cytoplasmic processes of tegument cells, whose soma lie underneath the two muscle layers. The surface of the tegument is highly folded and invaginated into numerous ridges, pits and spines, which help to increase the surface area of the tegument for the absorption and exchanging of molecules, as well as for attachment. The outer membrane covering the tegument is a trilaminate sheet about 12 nm thick, and coated with a carbohydrate-rich glycocalyx layer that also bears high negative charges. Some host molecules may also be adsorbed onto this layer. These unique characteristics enable the parasite to evade the antibody-dependent cell-mediated cytotoxicity (ADCC) reaction exerted by the host. The outer membrane and glycocalyx is continuously replaced by the reserved membrane synthesized and stored in secretory granules of tegument cells, that are transported via cell processes towards the tegument by microtubules. The basal membrane of the tegument is trilaminate and invaginated to form membrane infoldings with closely aligned mitochondria. The tegument cytoskeleton is composed of a highly cross-linked network of 4-6 nm knobby microtrabecular fibers, bundles of intermediate filaments, microtubules that splay out from the tegument cells' processes. Major proteins of the cytoskeleton are actin, paramyosin and tubulin. The flukes' antigens that can elicit strong immunological responses in animal hosts are synthesized and released mainly from the tegument and the cecum. The majority of antigens derived from the surface membrane and the tegument are of MW 97, 66, 58, 54, 47 and 14 kDa, while those released from the cecum are cysteine proteases of MW 27, 26 kDa. Monoclonal antibodies have been raised against some of these antigens, and have been employed in immunodiagnosis of the infection. From the protection conferred to animal models and the in vitro killing assays of young parasites by specific antibodies, candidate vaccines could be selected from these antigens, such as, an antioxidant enzyme, glutathione-S-transferase, the digestive enzyme cysteine proteases, the surface-tegument proteins, such as fatty acid binding protein (14 kDa), membrane proteins (at 66 kDa), as well as muscle protein paramyosin, and hemoprotein. Ongoing research have been directed at deciphering the genetic codes and the syntheses of some of these antigens by recombinant DNA technology.

The potential alveolar hazard of carbon dioxide laser-induced smoke

Carbon dioxide laser is a continuous wave laser, it is well known for its capacity of tremendous smoke production while contact with tissue. Smoke may cause nausea, vomiting, headache and airway irritation. Smoke particles 0.5-2 micrometers in diameter usually travel down the tracheobronchial tree and lodge in the alveoli posing a health hazard. The objectives of this study were to evaluate possible health hazards of carbon dioxide laser smoke in the operating room environment, by determining the size and density of smoke particles also determine the efficacy of surgical masks as a smoke protectant. Ten fresh specimens of papillomatous tissue obtained from the patients were lased by carbon dioxide laser in a continuous mode. The plume generated was collected by 0.45 micrometers pore size microfilter which was attached to the tip of a suction hose connecting the smoke evacuator. The effectiveness of 2 types of commonly used surgical masks were also determined by trapping the smoke after passing through each mask using the same model. Smoke particles were evaluated by scanning electron microscope. The smoke particle density of microfilter that directly trap plume averaged 6 particles/mm2, particles ranging in size from 0.5-27 micrometers, of which 70 per cent were 0.8 micrometers. For the particles trapped after passing through both cotton and paper surgical mask, the size were ranging from 1.6-37 micrometers where 65 per cent were 3.7 micrometers and the particle density average 2.7/mm2. We concluded that the smoke particles derived from carbon dioxide laser application are within the alveolar hazard zone. The conventional surgical masks may not be an effective tool against laser smoke hazard.

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.

Diagnosis of cattle fasciolosis by the detection of a circulating antigen using a monoclonal antibody

A monoclonal antibody (MoAb) 1C12 that reacts with a 66 kDa surface tegumental (ST) antigen of adult worms of Fasciola gigantica was used to detect circulating antigen in sera of experimentally and naturally infected cattle. A combination of rabbit anti ST-antigens and MoAb 1C12 were used to capture and detect the circulating antigen in sandwich ELISA. The dilutions of 1:1,000 of rabbit anti ST-antigens and 1:100 for MoAb 1C12 were used to reduce cross-reactivity with other trematodes' antigens. The circulating antigen of F. gigantica was demonstrated in sera of all experimentally infected animals as early as the first week after the infection, and it remained detectable until the experiment was terminated at week 32 after the infection. Of the 97 serum samples from naturally infected cattle, the sensitivity of 86.6% was observed when the cut-off point was calculated from 32 serum specimens from uninfected control calves. The sensitivity increased to 100% when the commercial fetal calf and trematode-free baby calves sera were used for calculation of the control cut-off point. Based on these results, the combination of rabbit anti ST-antigens and MoAb 1C12 sandwich ELISA appeared to be sensitive, specific, and applicable in the immunodiagnosis of fasciolosis in cattle for epidemiological study and monitoring of chemotherapeutic efficacy.

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.

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: 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)

Production and characterization of genus and species specific monoclonal antibodies against surface tegumental antigens of Schistosoma mekongi

A panel of monoclonal antibodies (MoAbs) against freeze-thaw surface tegumental antigens of Schistosoma mekongi were produced from naturally infected BALB/c mice. In this study, we have characterized two MoAbs which have different antigenic specificity for S. mekongi, S. japonicum and S. mansoni. The target epitopes of these two hybridoma antibodies are contained in the M(r) 38 kDa (designated Sme 38) and M(r) 97 kDa (designated Sme 97) proteins of adult worms as analysed by immunoblotting. The Sme 38 epitope was genus-specific, since it is also detectable in S. japonicum and S. mansoni. The Sme 97 was not detected in S. japonicum and S. mansoni, therefore it is considered as species-specific epitope. Immunocytochemical analysis revealed the presence of Sme 38 epitope in the surface tegument, the tegumental cells lying underneath the muscle layer and gut surface. The Sme 97 epitope was detectable only in the surface tegumental area.

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.

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.

Characterization of two monoclonal antibodies against teguments of adult and schistosomula of Schistosoma japonicum

Two monoclonal antibodies (McAbs) were produced from BALB/c mice hyperimmunized with tegumental extract of Schistosoma japonicum (Chinese strain). The two McAbs were characterized with regard to antibody isotype, antigen binding specificity and parasite stage specificity. One McAb, 8G9-5, was identified as IgM, whereas the other McAb, 9E7, was determined to be IgG2a. Immunoblotting assay indicated that McAb 8G9-5 binds strongly to the band of tegumental antigens of Mr 64 kDa but also binds weakly to other bands at 116, 105, 97, 54, 50, 47 and 45 kDa, whereas 9E7 McAb reacts specifically at Mr 54 kDa. Anatomical localization of the antigens in the adult worm by indirect immunofluorescence assay indicated that the target epitopes of McAb 8G9-5 are in the intra-tegumental structure, whereas the McAb 9E7 epitope is on the surface membrane. The two McAbs also react at similar sites within the teguments of schistosomula and lung worms.

Schistosoma japonicum (Chinese strain): characterization of two monoclonal antibodies which recognized common epitopes in the tegument of adult worms and schistosomula

Two monoclonal antibodies have been produced that bind to the common epitopes on adult and schistosomula of S. japonicum (Chinese strain). The isotypes of these monoclonal antibodies were determined to be IgM (designated 8G9-5) and IgG2a (designed 9E7) respectively. The target epitopes of 8G9-5 and 9E7, as analysed by immunoblotting assay, are at Mr of 64 kDa and 54 kDa respectively. Indirect immunofluorescence assay using frozen sections of adult worms, intact mechanically transformed schistosomula and 5-day-old lung schistosomula indicated that both epitopes are located in the tegument of both stages of parasite. These epitopes appear to be two of several major immunogenic proteins on the tegument of both young and adult worms.

The neural commissural rings of the adult male Schistosoma mansoni

Adult males of Schistosoma mansoni were preincubated in 5-hydroxytryptamine (5HT) and processed through the glyoxylic acid fluorescence technique to visualize 5HT-containing neural elements. 5HT fluorescence was seen as a series of cross-sectional rings beginning behind the ventral sucker toward the tail end. The rings were connected by two lateral nerve cords running longitudinally along the whole length of the worms.

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.

Topography and ultrastructure of the tegument of adult Schistosoma mekongi

The tegument of adult Schistosoma mekongi has been studied by both scanning and transmission electron microscopy. The gross surface topography of the parasite resembles that of S. japonicum, in that branched ridges, microvilli and sensory papillae predominate; such characteristics distinguish these two species from the non-oriental schistosomes. A unique feature of S. mekongi, however, is the numerous pleomorphic protruberances which are concentrated particularly on the middle three-fourths of the body surface. Transmission electron microscopy has revealed that these protruberances enclose bundles of microfilaments which appear to insert into the tegumental outer membrane. The microfilaments are suggested to have a supportive or stabilizing function, and may compensate for the absence of more typical crystalline spines. The tegumental outer membrane is typically heptalaminate in section, while the basal membrane infoldings are surrounded by concentrations of mitochondria. Three types of tegumental inclusion bodies have been recognized. Discoid bodies and membraneous bodies are morphologically identical to those described in all other schistosome species, except that the latter inclusions have been seen connected to each other and to the tegumental outer membrane by unique channels lined with trilaminate membrane. The third inclusion takes the form of spherical, lucent vesicles containing membrane fragments; these may represent the remains of spent membraneous bodies.

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.

Transmission and scanning electron microscopic studies of human sperm heads extracted with 8 M urea, 1% mercaptoethanol and different concentrations of salt

Transmission (TEM) and scanning (SEM) electron microscopic studies were performed on the human sperm heads extracted with (a) 1% Triton X-100, 1% mercaptoethanol (ME) and (b) 8 M urea, 1% ME together with increasing concentrations of NaCl ranging from 0.2 to 0.6 M. In the TEM study, the extraction of the nuclear material was first observed when the heads were treated with 8 M urea and 1% ME, with the majority of the chromatin remaining as 400-550 A thick interconnecting cords and oval bodies. At 0.2 M NaCl the cords and bodies were further separated but linked together by extremely thin 20-50 A fibers. Between 0.3 and 0.5 M NaCl the chromatin bodies within the sperm heads began to be extracted, first at the central part and progressively towards the periphery. Finally, at 0.6 M NaCl only the chromatin cords forming the periphery of the heads remained. In the SEM study, the sperm heads remained unbroken up to the treatment with 8 M urea, 1% ME and 0.2 M NaCl. Between 0.3 M and 0.5 M NaCl the majority of heads were disrupted to form interlacing chromatin cords of 400-550 A thick while the unbroken heads exhibited surface with cross-weaving cords. At 0.6 M NaCl all heads were disrupted and the remaining chromatin existed mostly as exoskeleton of former sperm heads. Protein gel electrophoresis showed that histones and nonhistones were removed from the chromatin when the treatment reached 0.2 M NaCl, whereas protamines started to be removed at 0.3 M, and totally removed at 0.6 M NaCl; HP1 was the first protamine fraction to be extracted.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Electron microscopic and biochemical analyses of the organization of human sperm chromatin decondensed with sarkosyl and dithiothreitol

Human sperm chromatin was decondensed by treating the purified sperm heads with Sarkosyl for 60 minutes followed with dithiothreitol (DTT) for 20 minutes and overnight. Following Sarkosyl treatment all histones and nonhistones were removed; the remaining nucleoprotamines in the sperm heads exhibited two levels of higher-order structure in the forms of 900-1200 A thick and 380-520 A thin knobby cords, which were randomly coiled. Subsequent treatment with DTT resulted in the dissociation of the 380-520 A cords into subunits of 180-210 A fibers, which were further decondensed into beads-on-a-string structure with diameter of the beads about 120-150 A.

Scanning electron microscopic study of the tegumental surface of adult Schistosoma mekongi

The surface topography of the tegument of adult Schistosoma mekongi was studied by scanning electron microscopy (SEM). In comparison to other species of human schistosomes the male tegument lacks tubercles and, except in the gynecophoral canal, also lacks spines; instead the surface is composed chiefly of trabeculae of highly perforated ridges which give it the 'spongy' appearance. In addition, there are 3 kinds of papillae interspersed on the surface among the ridges. The first is a doughnut-shaped papilla with a central crater which is most abundant on the ventral surface of the anterior part, on the floor of the gynecophoral canal and on the dorsal-lateral aspect of the tail. The second is a pleomorphic papilla with irregular shape and size, which is scattered throughout the dorso-lateral aspect of the middle part of the body. The third type of papilla has a uniform hemispherical shape, possesses a cilium projecting from its apex and probably corresponds to the 'sensory papilla' found in other species. The tegument of the female differs from that of the male by having numerous short spines over the whole surface; however, the pleomorphic papillae are much fewer in number and the ridges are much less developed than those of the male tegument; complex trabeculae are absent.

Transmission and scanning electron microscopic studies of the human sperm chromatin decondensed by micrococcal nuclease and salt

The human sperm chromatin was gently decondensed by treating the sperm head sequentially with micrococcal nuclease and 2 M NaCl. All histones, about 10% of DNA, and a small amount of degraded protamines were released into the soluble fraction, leaving mainly nucleoprotamines in the pellet fraction. Transmission and scanning electron microscopic studies revealed that the nucleoprotamine pellet consisted of chromatin cords of two dimensions, viz., 330- to 420-A and 650- to 1200-A thick cords laced together by very fine strands of 60- to 80-A fibers; both types of cord appeared knobby and had zig-zag patterns throughout their length. It appeared that these cords were derived from two types of sperm heads of approximately equal population; one type contained chiefly the thick cords and the other chiefly the thin cords. Further treatment of the pellet nuclease-NaCl with urea and mercaptoethanol resulted in the dissociation of the thick into the thin cords and unravelling of the thin cords into smaller sized fibers; whereas the treatment of the pellet nuclease-NaCl with DNAase I resulted in the disappearance of the 60- to 80-A fibers, and the remaining cords were chiefly of thick type together with the sperm head exoskeletons. From these results the packing order of the chromatin in human sperm was proposed.

Electron microscopic studies of rat sperm heads treated with urea, dithiothreitol, and micrococcal nuclease

Urea and dithiothreitol can decondense the chromatin in some of rat sperm heads. By this treatment, we have observed that in the nuclei of rat sperm the chromatin is organized into two morphologically distinct portions, namely: the compact chromatin rods of about 450 to 1,000 A thick, and the interlacing fibers about 250-290 A in thickness. When these treated sperm are further digested with micrococcal nuclease, the small fibers disappear, whereas the chromatin rods are still present in the "urea-nuclease pellet." From the available evidence, we suggest that the chromatin rods represent the highly packed nucleoprotamine, whereas the small fibers represent the more loosely organized nucleohistone.

Cytological changes in the testes of vitamin-A-deficient rats. I. Quantitation of germinal cells in the seminiferous tubules

Vitamin A deficiency was induced in young adult male rats by feeding them with a synthetic vitamin-A-deficient diet. The histology of their testes was examined periodically from 1 to 20 days following the point where the animals ceased to gain weight. The earliest sign of histological change in the seminiferious tubules, which occurred at day 3, was the sloughing of spermatids and spermatocytes into the lumina of the seminiferous tubules. Pyknotic cells were seen throughout the epithelium in a significant number beginning at day 4 or 5. Most of them were dead spermatocytes and early spermatids. Abnormal multinucleate giant cells appeared during days 6 and 8, and were thought to be abnormal spermatids which failed to complete cytoplasmic division and further differentiation into spermatozoa; eventually they degenerated. Quantitation of germinal cells in the tubules revealed that the number of spermatids decreased sharply between days 2 and 8, and reached zero level at day 10 after the animals ceased to grow. The number of spermatocytes decreased rapidly between days 5 and 12, and the rate of their decrease was relatively slow during the periods preceding and following this interval. Few spermatocytes remained in the tubules at day 20. In comparison, the decrease of spermatogonia was more gradual. At the end of the experiment, the number of spermatogonia in each tubule was about one fourth of that detected at the time when the animals ceased to grow. It was thought that the sloughing and the disintegration of the spermatocytes and spermatids were major factors responsible for their rapid disappearance from the tubules, and that fast dividing and differentiating cells like spermatocytes and spermatids were more vulnerable to vitamin A deficiency than spermatogonia.

Cytological changes in the testes of vitamin-A-deficient rats. II. Ultrastructural study of the seminiferous tubules

Ultrastructural study confirmed that, in rats, vitamin A deficiency initially caused the sloughing of some spermatids and spermatocytes into the lumina of the seminiferous tubules around day 3 following the initial decrease of body weight. From days 5 to 10, a considerable number of spermatocytes and spermatids, which still remained in the epithelium, underwent necrosis. Several stages of dying spermatocytes and abnormal spermatids were observed. The latter were distinguished by the presence of chromatin aggregating along the nuclear envelopes and highly vacuolated mitochondria. These cells range from single to multinucleate forms. They were incapable of differentiating further into spermatozoa and ultimately degenerated. Within the same period, Sertoli cells exhibited numerous darkly stained lysosome-like inclusions, and the upper part of their cytoplasm appeared as irregular processes, some of which were broken off and resulted in the thinning of the epithelium. From days 10 to 20, the remaining germ cells comprised mainly spermatogonia and few abnormal spermatocytes. The latter appeared enlarged and were very lightly stained. Their nuclei exhibited unusual blocks of heavily condensed chromatin amidst very highly dispersed chromatin fibers. Though their number was reduced, most of the spermatogonia appeared unaltered. Processes of Sertoli cells became even more irregular and were interrupted at certain sites by large empty spaces. Darkly stained inclusions in their cytoplasm were fewer than observed earlier.

Electron microscopic study of glomerular filtration barrier in the rat kidney embedded in polymerized glutaraldehyde-urea

Embedding kidney in polymerized glutaraldehyde-urea favors the retention of glycoprotein matrix of the cell coat and the basement membrane of the glomeruli. The basement membrane appears as a single layer with uniform amorphous matrix. Thick glycoprotein coat covers the whole surface of prodocytes and their foot processes. In areas other than the slits and the portion of the foot processes which touch on the basement membrane, the coat is a continuous layer with an average thickness of 490 A. In the slits between the foot processes of podocytes there is an actual fusion of glycoprotein coats; the average width of the slit is 415 A. The glycoprotein 'plugs' in the slit may be a significant portion of the glomerular filtration barrier against macromolecules, together with the basement membrane and the slit diaphragms.

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.