Showing papers in "Journal of Parasitology in 1981"
TL;DR: Schistosomules developed steadily to pairing, which was seen first during the 7th wk of culture, and Pairing occurred somewhat later in relation to development in vivo.
Abstract: Procedures are described for mass cultivation of Schistosoma mansoni. Cercariae were pooled, concentrated, and axenized through a series of washes in base medium containing antibiotics. Cercariae were sheared through a double-Luer-ended needle connected to two syringes, and tails separated and discarded. Young schistosomules were grown in a medium based upon BME augmented with lactalbumin hydrolysate, glucose, hormones, and other amendments and supplemented with human serum. Human blood cells (Type O) were added to cultures. Intestinal pigment was seen on the 5th day and gut cecal fusion began on day 11. Schistosomules developed steadily to pairing, which was seen first during the 7th wk of culture. Pairing occurred somewhat later in relation to development in vivo.
292 citations
TL;DR: (14 wk postinfection), the death rates were 36 and 40% in group A and B respectively, compared to 8% in the noninfected control (Table I).
Abstract: (14 wk postinfection), the death rates were 36 and 40% in group A and B respectively, compared to 8% in the noninfected control (Table I). Metacercarial production was high and continued for at least 50 days after the prepatent period (Table I). The procedure described appears to be valuable and useful for the cultivation of k postinfection), the d ath rates w re 36 40% in group A and B resp ctively, comed to 8% in the no infect d control (Table aquatic species of Lymnaea and for mass producti n of metacercariae of Fasciola gigantica. The m thod is simple and time saving and makes possible mass production of snails. The growth rate of juvenile snails was fast and the mortality of both noninfected and infected snails was low. ic species of Lymnaea nd for mass proio of metacercariae of Fasciola gi antie ethod is simple and time saving and s possible mas production of snails. The t rate of juvenile snails was fast and the
104 citations
TL;DR: Rhipicephalus appendiculatus passes through one generation per annum in the highveld of Zimbabwe, Rhodesia and shows a well-defined pattern of seasonal activity, whereas peak larval and nymphal activity occurs in the dry season.
Abstract: Rhipicephalus appendiculatus passes through one generation per annum in the highveld of Zimbabwe, Rhodesia and shows a well-defined pattern of seasonal activity. Peak adult activity occurs in the rainy season, whereas peak larval and nymphal activity occurs in the dry season. Adult activity is regulated by the combined influences of temperature, humidity, and day length. Climatic factors have little or no direct influence on the activity of larvae and nymphs. The occurrence of the larval and nymphal activity peaks is determined by the timing of the adult activity peak and the duration of the preceeding developmental periods, which are temperature dependent. In the early rainy season, unfed adults climb to the tips of the grass and enter a period of quiescence prior to becoming active.
75 citations
TL;DR: The results suggested that proteases of merozoites might play some crucial role in the invasion process of Plasmodium knowlesi merozosites.
Abstract: The effect of protease inhibitors obtained from the culture filtrates of actinomycetes (pepstatin, chymostatin, leupeptin, phosphoramidon and elastatinal) on the in vitro invasion of erythrocytes from rhesus and assamese monkeys by Plasmodium knowlesi merozoites was studied. The presence of these inhibitors had no effect on release of merozoites from schizonts but inhibited entry of the parasite into the red cell. Thus, at 50 micrograms/ml, chymostatin and leupeptin completely blocked the invasion whereas pepstatin and elastatinal showed 50% inhibition. Phosphoramidon at this concentration gave only 30% inhibition. Pretreatment of the erythrocytes with these inhibitors did not block invasion. Also, the intracellular development of the parasite was totally unaffected in the presence of these agents. These results suggested that proteases of merozoites might play some crucial role in the invasion process.
72 citations
TL;DR: Female worms which had degenerated upon separation from male worms for 3 mo regenerated and produced viable eggs when reunited with mature males, indicating that separation of females from their male partners leads to a reversible degeneration of the female reproductive tract.
Abstract: Mature, egg-producing female worms from bisexual cercarial infections in mice were transplanted surgically either without male worms, to produce unisexual infections in recipient hamsters, or with male partners to produce bisexual infections. The morphology of the female reproductive organs and oogenesis in the unisexually and bisexually transplanted females were compared over a 9-day period. Females which paired with male worms in hamsters continued to produce eggs throughout the experiment. In contrast, unisexually transplanted females exhibited degeneration of the vitellaria at 3 days and the ovary at 6 days posttransplantation, although these worms produced fertilized oocytes as late as 9 days following transfer. Female worms which had degenerated upon separation from male worms for 3 mo regenerated and produced viable eggs when reunited with mature males. Thus, separation of females from their male partners leads to a reversible degeneration of the female reproductive tract.
70 citations
TL;DR: A range of nonsusceptibility among stocks of Biomphalaria glabrata susceptible to the NIH-Sm-PR-1 strain of Schistosoma mansoni is observed, and Parasite development and host tissue response also varied among three stocks of snails that were susceptible to PR-2.
Abstract: Of 10 inbred stocks of Biomphalaria glabrata examined, eight were susceptible to the NIH-Sm-PR-1 strain (PR-1) of Schistosoma mansoni, whereas only three were susceptible to the NIH-Sm-PR-2 strain (PR-2). By employing a histological ranking system based on parasite development and host tissue response, we have observed a range of nonsusceptibility among stocks nonsusceptible to PR-2. In three nonsusceptible stocks, sporocysts were rapidly surrounded by host amebocytes and were destroyed within a few days. However, in four other nonsusceptible stocks, sporocysts were surrounded by only a minimal host reaction and some sporocysts persisted for at least 3 weeks. Nondevelopment of sporocysts in these four stocks may result from biochemical unsuitability or a weak from of resistance in the host. Parasite development and host tissue response also varied among three stocks of snails that were susceptible to PR-2. In two susceptible stocks, most PR-2 sporocysts developed normally, and the small proportion that underwent degeneration elicited no host cellular response within the first week of infection. However, in a third susceptible stock, most sporocysts were surrounded by a minimal host reaction and very few appeared to develop normally.
70 citations
TL;DR: Results indicated that free Eimeria tenella sporozoites may incorporate a potentially lethal concentration of the polyether ionophorous antibiotics and that a coccidiocidal activity may be expressed whether or not penetration of host's cells occurs.
Abstract: Free Eimeria tenella sporozoites were exposed to the anticoccidial ionophores monensin, lasalocid, narasin, or salinomycin for 4 hr at 40 C, whereupon the drugs were removed by dilution centrifugation and the parasites inoculated into cultures of chick kidney cells. Cultures were fixed and stained at 4 and 96 hr postinoculation to determine the effect of ionophore uptake by the extracellular sporozoites on invasion and development. Pretreatment with each of these antibiotics significantly reduced the number of intracellular sporozoites and dramatically inhibited asexual development. These effects were dose-dependent. Exposure of free (extracellular) sporozoites to monensin at 40 C caused a significant decline in the number of surviving organisms over time as compared to nontreated sporozoites. This response also appeared to be dose-dependent. Scanning and transmission electron microscopy revealed that the surface of the treated sporozoites was very irregular and the organisms often exhibited a gross swelling. These results indicated that free Eimeria tenella sporozoites may incorporate a potentially lethal concentration of the polyether ionophorous antibiotics and that a coccidiocidal activity may be expressed whether or not penetration of host's cells occurs.
63 citations
TL;DR: The terminol- ogy, "pigmentation dystrophy," is proposed as more appropriate than the previously used terms, "non- pigmentation," 'depigmentation," and "color dichromatism" for the occurrence of altered pigmentation in hosts infected with species of Acanthocephalus.
Abstract: The isopods Asellus intermzedius, Lirceus garmani, and L. lineatus were studied to document further the occurrence of altered pigmentation in these hosts infected with species of Acanthocephalus. Specimens of A. intermedius from central Illinois, L. garmani from northwestern Arkansas, and L. lineatus from northwestern Ohio revealed differences in normal integumental pigmentation related to species, sex, reproductive state, and size. Integument of males and females of the three species was found to be more lightly pigmented when specimens harbored male, female, or multiple infections with acanthocephalans. Comparisons of light transmission through wholemounts of respiratory opercula of A. interinedius dem- onstrated that there was no significant difference in pigmentation among infection types. Regression analyses indicated (1) that the normnnal relationship between isopod length and pigmentation had been disrupted by acanthocephalan infections; (2) that a developmental relationship existed between isopod (length) and acanthocephalan (volume); (3) that there was not a direct relationship between acanthocephalan size and altered pigmentation, as might be expected for a gradual "depigmentation" process; and (4) that eye size was unaffected by parasitism. On the basis of these findings, the terminol- ogy, "pigmentation dystrophy," is proposed as more appropriate than the previously used terms, "non- pigmentation," 'depigmentation," and "color dichromatism."
58 citations
TL;DR: Toxoplasma gondii is capable of de novo pyrimidine biosynthesis, and may also be able to use pyrimidines of the host cell, because of pyrazofurin.
Abstract: Pyrimidine biosynthesis was studied in actively dividing, intracellular Toxoplasma gondii, in mutant Chinese hamster ovary cells blocked in pyrimidine biosynthesis to eliminate any contribution by the host cell. The parasite grew normally in these cells even though pyrimidines were not supplied in the medium. Uninfected, mutant cultures showed negligible pyrimidine synthesis. However, mutant cultures infected wit T. gondii efficiently incorporated 14C from glucose or aspartic acid into the pyrimidine bases of nucleic acids. Thus T. gondii is capable of de novo pyrimidine biosynthesis. The parasite may also be able to use pyrimidines of the host cell, because of pyrazofurin, an antimetabolite that blocks pyrimidine biosynthesis, markedly inhibited only a mutant parasite defective in the salvage of pyrimidines.
53 citations
TL;DR: Although larval growth and development were similar in all systems tested through 14 days in culture, higher yields of advanced stages of L4 were obtained in systems DM-200 and DM-S, and developing larvae released metabolic products into the culture media that stimulated a specific blastogenic response in lymphocytes obtained from A. suum-infected swine.
Abstract: A population of early to late third-stage larvae (L3) of Ascaris suum obtained from the lungs of swine 7 days after infection developed to the fourth stage (L4) in stationary, multi-well, culture plates in an atmosphere of 5% CO2 in air. Larval survival, growth and morphogenesis were evaluated in five culture systems consisting of Dulbecco's Modified Eagles' Medium alone (DM) or containing a serum supplement (DM-S) or a tripeptide (1-glycyl-1-histidyl-1-lysine) at final concentrations of 20, 200, and 1,000 ng/ml (respectively, DM-20, DM-200, and DM-1,000). The rate of development and morphogenesis of larvae from L3 to L4 was optimal in the DM-S culture system and similar to that observed in vivo. However, development beyond L4 was retarded in vitro; sex was not distinguished until 21 days in culture (DIC) and the largest L4 obtained after 52 DIC was 9.2 mm long. Although larval growth and development were similar in all systems tested through 14 days in culture, higher yields of advanced stages of L4 were obtained in systems DM-200 and DM-S. Developing larvae released metabolic products into the culture media that stimulated a specific blastogenic response in lymphocytes obtained from A. suum-infected swine.
TL;DR: It is demonstrated that host sex and host sex hormones affect the biology of T. spiralis in the CD-1 Swiss white mouse.
Abstract: The effects of host's sex and hormones on the number of adult Trichinella spiralis in the small intestine, the number of migratory larvae produced in vitro by adult female worms, and the number of muscle larvae per gram of body weight were examined in CD-1 Swiss white mice. Nongonadectomized (intact) male mice housed greater numbers of adult worms and a greater number of muscle larvae per gram of body weight than did intact female mice. Adult female worms isolated from intact male mice deposited greater numbers of migratory larvae in vitro than did those obtained from intact female mice. These differences between intact male and intact female mice were eliminated by gonadectomy of male and female mice. Injection of increasing amounts of heterologous sex hormone into intact male and female mice was accompanied by decreasing rates of in vitro larvaposition by adult worms from male mice; but adult worms isolated from female mice showed increasing rates of in vitro larvaposition. Injection of heterologous sex hormone into gonadectomized male and female mice caused a reversal of the findings for intact, uninjected male and female mice stated above. This study has demonstrated that host sex and host sex hormones affect the biology of T. spiralis in the CD-1 Swiss white mouse.
TL;DR: Alterations of gas phase or addition of reducing agents, antioxidants, steroid hormones, specific adsorbents, or adult worm extracts did not improve the worms or augment egg production.
Abstract: Schistosoma mansoni grown from the cercarial stage in vitro produced infertile eggs in about 10% of the pairs studied. Cultured eggs were about half normal size, had a small and blunt lateral spine, and appeared to lack a germinal disc. The shell opposite the spine was typically thin and poorly formed. Eggs were often found in dyads. Vitelline conglomerates in long strands were sometimes deposited. Vitelline glands, ovaries, and testes were relatively poorly developed. Alterations of gas phase or addition of reducing agents, antioxidants, steroid hormones, specific adsorbents, or adult worm extracts did not improve the worms or augment egg production.
TL;DR: This report presents details of a method to isolate large numbers of sterile schistosome eggs from the intestines of mice infected with S. mansoni or S. japonicum, and the sieving methods used are not novel.
Abstract: The principal lesions in schistosomiasis are caused by host reactions against the eggs of the causative organisms. Increasing interest in the immunology and physiology of schistosome eggs during the last several years necessitates methods for isolation of these eggs in pure form. Such methods generally consist of digestion of tissues from infected animals by either autodigestion or the addition of proteases such as trypsin, homogenization, screening to remove host tissue debris, and collection and concentration by centrifugation and/or sedimentation. The methods published to date have utilized principally liver tissue from infected animals (hamster or mice) because this tissue is relatively easy to work with. Nevertheless, the intestines of infected animals are very rich in eggs and should provide a good source for studies. This report presents details of a method to isolate large numbers of sterile schistosome eggs from the intestines of mice infected with S. mansoni or S. japonicum. Mice infected with Schistosoma mansoni (Puerto Rican strain) or Schistosoma japonicum (Formosan strain) were sacrificed at 7 to 8 wk postinfection by injection with 0.2 ml sodium pentothal and the intestines removed and washed in tap water; the large intestine was cut off and discarded. The small intestines were cut longitudinally with a sharp scalpel and the fecal contents and mucosal layers scraped with a scalpel and discarded; mesenteric tissue and surrounding fatty tissue were also removed surgically. As noted by Coker and Lichtenberg (1956, Proc. Soc. Exp. Biol. Med. 92: 780-782), the more residual fat, the more difficult it is to obtain clean eggs. The intestines were then pooled in 0.2 M NaCl and left overnight at room temperature. The following day, the intestines in batches of ten are suspended in 100 ml of 0.2 M saline and rapidly disrupted in a commercial model Waring Blendor (Model 31BL46). The disruption procedure consists of two consecutive 20sec bursts of homogenization with a short, 10sec period between each burst. The homogenate is immediately poured over a 20-cm diameter U.S. Standard Size Sieve #40 (sieve opening = 420 mgu) and washed with 500 ml saline. After all intestines are disrupted and passed through this filter, the material is passed through a series of 20-cm U.S. Standard sieves stacked as follows: #40 (420 m,i), #80 (177 m,u), #100 (149 mgi), #200 (74 mit), #325 (44 mgx); approximately one liter of saline is used to rinse these sieves, by gravity. The eggs pass through all the filters except the last where they are collected, resuspended in 500 ml saline and once again run through the stack of sieves. The eggs collected on the #325 sieve are washed extensively (some immature eggs, egg shell fragments and small debris pass through this sieve, as well as bacterial contaminants) with sterile saline. The eggs are finally collected by rinsing from the #325 sieve with sterile saline into conical 50-ml centrifuge tubes and centrifuged in a Sorvall GLC-1 centrifuge. By bringing the centrifuge to 2,000 rpm and then immediately shutting it off, the eggs are concentrated while some debris will float to the top from which it can be removed. The methods described above are not novel; similar sieving methods have been reported for mouse liver by Griffith and Beesley (1955, Trans. Roy. Soc. Trop. Med. Hyg. 49: 301), hamster tissues by Ritchie and Berrios-
TL;DR: The glycogen content of muscle was correlated with the activity of glycogen synthase and glycogen phosphorylase from the parasitic roundworm Ascaris suum maintained in vitro and total levels of both enzymes remained constant over the starvation-feeding period.
Abstract: The glycogen content of muscle was correlated with the activity of glycogen synthase and glycogen phosphorylase from the parasitic roundworm Ascaris suum maintained in vitro. Adult female worms were maintained in the laboratory in a perfusion system during periods of starvation and feeding. During starvation, the levels of glycogen decreased at a rate of 0.1 to 0.2 t/moles/min/g wet weight of muscle-cuticle. During this time, 95% of the glycogen synthase (E.C. 2.4.1.11) was in the inactive D-form, and 48% of the phosphorylase (E.C. 2.4.1.1) was in the active a-form. Upon feeding, the rate of incorpo- ration of glucosyl residues into glycogen proceeded at a rate of 0.75 to 1.0 ,umoles/min/g muscle-cuticle. Glycogen synthase was 22% in the active I-form and phosphorylase a-levels remained virtually unchanged at 41% as compared with the starved worm. Total levels of both enzymes remained constant over the starvation-feeding period with 3.9 units/g phosphorylase and 0.4 units/g glycogen synthase. The apparent Km value for the substrate UDPG for glycogen synthase was 0.22 ? 0.02 mM. For glycogen phosphorylase the K,,, value for G-1-P was 1.76 + 0.38 mM. The muscle of the parasitic roundworm, Ascaris suum, contains large quantities of gly- cogen amounting to 15% of the wet weight (Harpur, 1963). This glycogen acts as the sole source of energy in the muscle of the worm (Fairbairn, 1970; Saz, 1970), and glycogen levels have been shown to decrease upon starvation of the parasites in vitro (Harpur,
TL;DR: Skin tests on guinea pigs in which extracts of tick salivary glands were used as the antigens did not conclusively reflect the same patterns ofCross-reactions noted in the tests of cross-resistance.
Abstract: The ability of guinea pigs to acquire resistance to Dermacentor andersoni and Amblyomma americanum was determined by repeatedly infesting separate sets of guinea pigs with tick larvae. Resistance was measured in terms of reduced numbers successfully engorging and reduced weight of those ticks that engorged. An 83% reduction in numbers of larvae engorging and a 64.5% reduction in the weight of engorged larvae were seen between the first and second infestations with D. andersoni. Guinea pigs exhibited considerably less resistance to A. americanum the third time they were exposed to this species than did guinea pigs infested twice with D. andersoni. Feeding success was only 30.8% less than the initial percentage that engorged, and the percentage weight reduction was 35. During the challenge infestations, sizable fluid-filled vesicles formed on ears of the guinea pigs used as hosts for D. andersoni or A. americanum. Cross-resistance was evaluated by dividing D. andersoni-resistant animals into groups and challenging them with D. andersoni D. variabilis, A. americanum, or Ixodes scapularis. Appreciable cross-resistance was apparent between the two Dermacentor species. The weights of the A. americanum and I. scapularis were significantly reduced, but not the number that engorged. When A. americanum-resistant guinea pigs were challenged, they were cross-resistant to D. variabilis but not to D. andersoni. Skin tests on guinea pigs in which extracts of tick salivary glands were used as the antigens did not conclusively reflect the same patterns of cross-reactions noted in the tests of cross-resistance.
TL;DR: C-banded methods revealed a large heterochromatic block in one for the No. 2 chromosomes in females but not in the other, and the two species differed in that the centromeric index of the Z of S mansoni was smaller than that of the W, whereas in S rodhaini the reverse was true.
Abstract: The karyotypes of a Puerto Rican strain of Schistosoma mansoni and a Kenyan strain of S. rodhaini are similar in number and general morphology. For each species there are eight pairs of chro- mosomes (2n = 16) which are divided into three size groups. C-banding methods revealed, in addition to centromeric heterochromatin, a large heterochromatic block in one of the No. 2 chromosomes of females but not in the other. Neither No. 2 chromosome of males possessed the heterochromatic block. This pair (2) is interpreted as the sex chromosomes, with the female being heterogametic (ZW), the male homoga- metic (ZZ). Differences between karyotypes of the two species occurred. These include a satellite on the No. 3 chromosome of S. mansoni and a euchromatic tip on the otherwise heterochromatic short arm of the W chromosome of this species; neither of these was present in S. rodhaini. The two species also differed in that the centromeric index of the Z of S. mansoni was smaller than that of the W, whereas in S. rodhaini the reverse was true. In S. mansoni the large heterochromatic block of the W chromosome was identified in prophase and interphase nuclei as well as at metaphase. Schistosoma mansoni and S. rodhaini are closely related species in the lateral-spined egg group of African schistosomes. Both cause intestinal schistosomiasis, adults and cercar- iae are very similar in morphology, and both use species of Biomphalaria as snail hosts. Experimental evidence that these two species are related was provided by reports of hybrid- ization in the laboratory (Le Roux, 1954; Tay- lor, 1970). The chief morphological feature used to separate the two species has been egg shape (Berrie and Goodman, 1962; Taylor, 1970). Additional differences occur in natural defin- itive hosts: S. rodhaini is considered to be chiefly a parasite of wild rodents, whereas S. mansoni is a well-known parasite predomi- nantly of humans. Comparison of karyotypes of these two species, in the context of a wider study, might throw light on the relationship of the two, as well as on their systematic position in the family Schistosomatidae. We also were inter- ested in detecting differences which might serve to distinguish the two species and pro- vide a basis for the study of chromosomes of progenies in hybridization studies. In addi- tion, we wanted to follow up earlier sugges- tions that sex chromosomes could be identi- fied in both species.
TL;DR: It is concluded that pairs once mature in vivo could regain the capacity for oviposition even after prolonged maintenance in vitro, but worms grown entirely in vitro to pairing may have missed some required stimulus which cannot be furnished later, even by an adequate animal host.
Abstract: By injection into mice we assessed the potential for full development and oviposition of young schistosomules, juveniles, and paired adults of Schistosoma mansoni, all grown in vitro from cer- cariae. Schistosomules 2-hr or 13-days-old were injected into mice via the tail vein; older worms were implanted surgically into the ileocolic vein. Also implanted were previously ovigerous adult pairs that had been perfused from mice and maintained in culture up to 53 days. Eventually, all were capable of pro- ducing viable eggs except the worm-pairs that had been grown to the adult stage in vitro; these failed to grow or develop further when implanted into mice. We concluded that pairs once mature in vivo could regain the capacity for oviposition even after prolonged maintenance in vitro, but worms grown entirely in vitro to pairing may have missed some required stimulus which cannot be furnished later, even by an adequate animal host.
TL;DR: This method of isolation facilitates the recovery of this protozoan directly from small intestine for morphological and experimental study and shows marked reduction in contamination of attached trophozoites and dish surfaces after the use of cold temperature detachment and reattachment.
Abstract: A method for the isolation of Giardia trophozoites based on their ability to attach to warm surfaces has been developed. Mucosal scrapings were obtained from the small intestine of rats infected with Giardia and suspended in Hanks' balanced salt solution (HBSS). Trophozoites were concentrated by centrifugation and allowed to attach to the surfaces of polystyrene petri dishes incubated at 37 C. Incubation temperature significantly affected the recovery of trophozoites. After attachment at 37 C, trophozoites were separated from contaminating intestinal debris by incubation at cold temperature. The trophozoites detach at 4 C, whereas the intestinal debris remain adherent. Then the detached trophozoites were isolated by reattachment at 37 C. Examination by scanning electron microscopy revealed a marked reduction in contamination of attached trophozoites and dish surfaces after the use of cold temperature detachment and reattachment at 37 C. Viability of trophozoites as measured by erythrosin-B dye exclusion, remained above 90% up to 120 min after isolation. This method of isolation facilitates the recovery of this protozoan directly from small intestine for morphological and experimental study.
TL;DR: Examination of the carcass by scanning electron microscopy revealed that most of the exposed tegument of both male and female worms was removed, while surface membrane protected by close apposition of another surface (i.e., in the gynecophoral canal) remained intact.
Abstract: Tegumental membranes of Schistosoma mansoni were disrupted by 0.2% Triton X-100 in Tris-maleate buffered/Kreb-Ringer's solution. Subsequent differential centrifugation of the disruption solution at 2,500 g and 30,000 g produced two pellets which contained membrane components. Examination of the carcass by scanning electron microscopy revealed that most of the exposed tegument of both male and female worms was removed, while surface membrane protected by close apposition of another surface (i.e., in the gynecophoral canal) remained intact. The parenchymal tissue (e.g., subtegumental muscle and tegumental perikarya), excretory and gut epithelia, and the tegument's basement membrane also remained intact. The selectivity of the disruption suggests that membrane in both pellets originated almost exclusively from the tegument. Although larger morphological features (i.e., surface crypts) present in the intact tegument did not maintain their form in the 2,500 g pellet, the high specific activity of 3H-concanavalin A retained by this fraction, and the presence of numerous spines and large pieces of membrane, suggest that the 2,500 g pellet contained most of the worm's disrupted surface membrane. Transmission electron microscopy demonstrated the presence of dense spinelike material and vesicles of various sizes and densities, as well as some mitochondria in the 30,000 g pellet. Low specific activity of 3H-concanavalin A in the post-30,000 g supernatant suggests that relatively few externally oriented, saccharide-containing molecules were solubilized from tegumental membranes by Triton X-100.
TL;DR: The host responded to the presence of the parasites with connective tissue hyperplasia and with an infiltration of leukocytes, predominantly lymphocytes and eosinophilic granulocytes, which resulted in the formation of a tunnel around the neck and capsule around the bulb and proboscis of the parasite.
Abstract: The histopathology present in Etheostoma caeruleum naturally infected with the acantho- cephalans, Acanthocephalus dirus and Pomphorhynchus bulbocolli, was studied and described. The major difference in parasite-induced histopathology was related to the shallow penetration of A. dirus proboscides in the intestinal wall as compared to the penetration of P. bulbocolli. The host responded to the presence of the parasites with connective tissue hyperplasia and with an infiltration of leukocytes, predominantly lymphocytes and eosinophilic granulocytes. The response was greater to P. bulbocolli than to A. dirus. The complete penetration of the intestinal wall by the proboscis, bulb, and neck of P. bul- bocolli elicited an intense host response. This resulted in the formation of a tunnel around the neck and capsule around the bulb and proboscis of the parasite. Damage to the epithelial lining of the intestine occurred in areas of contact with the trunk of the parasites. Concurrent infections were common, but there did not appear to be a synergistic effect as a result of the presence of both parasites.
TL;DR: Serum transfer from hyperimmune rats provided a significant degree of protection against Strongyloides ratti in mature, recipient rats, and in vitro sensitization of infective larvae with rat antibody failed to alter in vivo viability.
Abstract: Serum transferred from hyperimmune rats provided a significant degree of protection against Strongyloides ratti in mature, recipient rats. Eight immune serum pools tested were effective; however, the level of protection, as measured by challenge worm recoveries, ranged from 32 to 91%. Protection did not increase consistently with increasing volumes of immune serum, although as little as 5.0 ml/100 g of body weight afforded consistent protection against challenge infection. The protective effect was exerted against the early migrating tissue stages of the larvae; immune serum given 24 hr after challenge or later had no effect. The specificity of the immune serum's protection was suggested by the removal of this activity by absorption with heat-killed larvae, which have been shown to induce protection by immuni- zation. Fractionation of immune serum showed that a heat-stable 7S component was responsible for pro- tection; no protective activity could be detected in the 19S fraction. Further resolution of the 7S fraction by DEAE ion-exchange chromatography confirmed that the serum's protective activity was in the IgG component. The greatest protection was obtained with the fraction containing predominantly IgG,. In vitro sensitization of infective larvae with rat antibody failed to alter in vivo viability.
TL;DR: The mitochondrial electron transport system of adult Hymenolepis diminuta exhibited an apparent specificity in terms of reduced pyridine nucleotide utilization, and a coupling of the NADPH : NAD transhydrogenase with mitochondrial electron Transport was demonstrated using disrupted mitochondria and mitochondrial membrane preparations.
Abstract: The mitochondrial electron transport system of adult Hymenolepis diminuta exhibted an apparent specificity in terms of reduced pyridine nucleotide utilization. The preferred substrate for both the minor oxidase and the physiologically required fumarate reductase system was NADH. Intramito- chondrial reducing equivalents, needed for phosphorylation via the anaerobic, electron transport-depen- dent, fumarate reductase, were generated as NADPH by the action of the cestode's NADP-specific "malic" enzyme. However, H. diminuta mitochondria catalyzed an NADPH: NAD transhydrogenation which would serve in hydride ion transfer from NADPH to NAD, thereby producing NADH required for the anaerobic, electron transport mechanism. Accordingly, NADPH utilization was increased when NAD was added to the mitochondrial system. The most significant increase occurred in the presence of both NAD and fumarate. These data indicate a coupling of the NADPH: NAD transhydrogenase with mitochondrial electron transport. This coupling of the transhydrogenase with electron transport was demonstrated using disrupted mitochondria and mitochondrial membrane preparations. Under conditions of reduced oxygen tension, the coupling of the transhydrogenase to fumarate reduction was apparent. In adult Ascaris suum, where the "malic" enzyme physiologically utilizes NAD, the mitochondria differ from those of H. dimi- nuta because NADPH: NAD transhydrogenase activity was minimal under the conditions of assay. The rate of NADPH utilization by the nematode mitochondrial system is not increased appreciably in the presence of NAD when either oxygen or fumarate serves as the acceptor.
TL;DR: Whereas serologic tests in rats and mice were reasonably sensitive in predicting infection, this was not so in chickens and sparrows which actually had a higher infection rate than the mammals tested.
Abstract: Epidemiologic studies for Toxoplasma infection often rely unquestioningly on serologic tests as if necessarily they were sensitive indicators of past or present infection. To compound the problem, the sera are often screened at higher dilutions than are generally found positive in birds. In a recent study of animals in Florida (Burridge et al., 1979, AJVMA 175: 964-967) the indirect hemagglutination test was used at at dilution of 1:64. Positive tests were found in 8.4% of 2,179 mammals, ranging between 11 and 19% in opossums, rats, raccoons, and armadillos. However, only 0.6% of 1,279 bird sera were reactive. This was interpreted that ". . . birds appear to have a minor role in the maintenance of T. gondii infection in Florida." In a similar survey in California, though using a kit of a different manufacturer, antibody reactivity was found in 14.4% of 1,132 mammals but only in 4.4% of 125 birds (Franti et al., 1975, JAVMA 167: 565-568). There are several isolated observations on finding low, transient or unmeasurable antibody titers in experimentally infected chickens using dye, complement-fixation or fluorescent antibody tests (Jones et al., 1959, J. Parasit. 45: 31-37; Boch et al., 1966, Berl. Munch. Tierarztl Wchsch., 79: 352-356). A recent study in an epidemiologic setting illustrates the insensitivity of usual serologic methods to detect Toxoplasma infection in chickens and sparrows (Ruiz and Frenkel, 1980, Am. J. Trop. Med. Hyg. 29: 1161-1166). Toxoplasma was isolated from brain or skeletal muscle from 54% of 50 chickens from Costa Rican farms and from 16% of 106 sparrows all of which were seronegative in the dye test at 1:2. By comparison, 11% of 107 rats had antibody and Toxoplasma was isolated from 12.5%; also, 6% of 202 mice had antibody and Toxoplasma was isolated from 3.5% by passaging brain. Whereas serologic tests in rats and mice were reasonably sensitive in predicting infection, this was not so in chickens and sparrows which actually had a higher infection rate than the mammals tested.
TL;DR: The parasite population after differentiation to metacyclic type forms showed a higher degree of infectivity than the original population constituted mostly by epimastigotes, suggesting the importance of factors from the insect vector in differentiation of T. cruzi.
Abstract: The influence that extracts of different T. infestans organs possess to induce Trypanosoma cruzi differentiation from epimastigotes to metacyclic forms in Grace's and modified Grace's media was analyzed. Growth of epimastigotes was adequate in Grace's medium when homogenates of stomach, testes, and ovaries from recently fed insects were added. Growth of epimastigotes was adequate when testes or ovaries obtained from recently fed triatomes were added to modified Grace's medium. Similar results were obtained in Grace's or modified Grace's media supplemented with stomach or intestinal homogenates obtained from "starved" triatomes. None of the above culture conditions induced differentiation of epimastigotes to the metacyclic stage. When extracts of intestine or stomach obtained from triatomes fed 24 to 48 hr previously were used to supplement the modified Grace's medium, growth and differentiation to the metacyclic stage was induced in a high percentage of the population. When extracts of intestine obtained from recently fed insects were used to supplement Grace's medium, differentiation and growth was an in modified Grace's medium. No important differences were observed if cultures were prepared at pH 6.4 or 7.0. The triatome food source did not seem to be important for the differentiation. The parasite population after differentiation to metacyclic type forms showed a higher degree of infectivity than the original population constituted mostly by epimastigotes. These studies suggest the importance of factors from the insect vector in differentiation of T. cruzi.
TL;DR: This species is the first ascaridoid which normally matures in fish that has been shown to penetrate the alimentary tract of a primate and therefore human consumption of raw seafood from at least the northern Gulf of Mexico free from infections does not necessarily assure freedom from anisakiasis.
Abstract: Within a few hours after being administered to the rhesus monkey (Macaca mulatta), Hysterothylacium type MB larvae penetrated the stomach wall, causing hemorrhage and attracting eosinophils Inocula up to 300 larvae, however, did not cause peripheral hypereosinophilia This species is the first ascaridoid which normally matures in fish that has been shown to penetrate the alimentary tract of a primate Consequently, human consumption of raw seafood from at least the northern Gulf of Mexico free from infections, with Anisakis spp, Phocanema decipiens, or other species that mature in mammals or birds does not necessarily assure freedom from anisakiasis as previously assumed
TL;DR: It is reported that primary infection with T. spiralis in the mouse increased gut propulsion on day 5 after infection but not 9 days after infection, suggesting that early inflammation influences peristaltic activity and propulsion of intestinal contents.
Abstract: Previous investigators have shown that Trichinella spiralis increases intestinal motility and propulsion. We report here that primary infection with T. spiralis in the mouse increased gut propulsion, measured by the movement of nonabsorbable chromatography beads, on day 5 after infection but not 9 days after infection. Both cortisone acetate, an anti-inflammatory agent, and Lomotil?, which reduces gut motility, could suppress the increase in gut propulsion seen 5 days after infection. The results suggest that early inflammation influences peristaltic activity and propulsion of intestinal contents.
TL;DR: Studies on oncospheres cultured in vitro in sera collected from animals during immunization or after oral challenge showed that most cysts were killed before 7 days of culture had elapsed, providing circumstantial evidence that the high degree of resistance stimulated by two or more injections may only be transient.
Abstract: A high level of resistance to oral infection with Echinococcus granulosus eggs was stimulated in lambs by two or more subcutaneous injections of oncospheres given 14 days apart. The degree of resistance was significantly higher than that resulting from a single injection. Resistance was apparently stimulated by the activated oncosphere or a stage of cyst development prior to 14 days of age. Studies on oncospheres cultured in vitro in sera collected from animals during immunization or after oral challenge showed that most cysts were killed before 7 days of culture had elapsed. This confirmed the observation that resistance was stimulated by an early stage of cyst development. The in vitro test also showed that two injections of oncospheres resulted in a marked increase in the lethal effects of serum. These lethal effects decreased with time, providing circumstantial evidence that the high degree of resistance stimu- lated by two or more injections may only be transient.