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.