Showing papers in "Journal of Parasitology in 1984"
175 citations
TL;DR: This report is a summary of the published records of parasites found from the marine and estuarine fishes of California, Oregon, and Washington.
Abstract: This report is a summary of the published records of parasites found from the marine and estuarine fishes of California, Oregon, and Washington. Coverage has not been limited to the western United States, but rather includes parasite reports from throughout each fish's range. Included is a host-parasite list and parasite-host crossindex.
106 citations
TL;DR: A comparative analysis of the cercarial shedding of 2 Schistosoma mansoni populations originating from the same endemic area (Guadeloupe) allows us to distinguish an early (peak emergence at 1100 hr) and a late (peak at 1600 hr) shedding patterns of cercariae.
Abstract: A comparative analysis of the cercarial shedding of 2 Schistosoma mansoni populations originat- ing from the same endemic area (Guadeloupe) allows us to distinguish an early (peak emergence at 1100 hr) and a late (peak at 1600 hr) shedding patterns of cercariae. This intraspecific variation in the chronobiology of S. mansoni cercariae may be related to the ecology in the transmission site. The early shedding pattern char- acterizes schistosome populations originated from urbanized foci where man plays the main role in the parasite transmission; the late shedding pattern characterizes schistosome populations originated from sylvatic focus where a rat (R. rattus) is the main host. The late shedding of cercariae is considered as an adaptation favoring transmission to a murine host whose behavior is preferentially crepuscular. All studies concerned with the cercarial shed-
102 citations
TL;DR: It was found that encystation could be triggered without change in the osmolarity of the medium and that oxygen does not influence this process.
Abstract: A procedure has been developed for the effective induction of axenic encystation of Entamoeba invadens strain IP-1. Low concentrations of glucose in Diamond's axenic growth medium cause stimulation of the differentiative process. The time course of encystation depended on the density of inoculum. While a culture with an inoculum of 5 X 10(4) cells/ml required about 3 days to initiate encystment, a culture with an inoculum of 1 X 10(6) cells/ml required only 8 hr. Cyst yield was optimal (70%) when a density of 5 X 10(5) cells/ml was employed for the inoculum. Under above conditions it was found that serum is absolutely required while vitamins are not. It was found that encystation could be triggered without change in the osmolarity of the medium and that oxygen does not influence this process.
81 citations
TL;DR: Type HA can be differentiated from the 6 thirdstage larval types belonging to the genus Terranova that have been adequately described by the relative lengths of the ventriculus and intestinal cecum by possessing a c Cecum that is much shorter than the Ventriculus.
Abstract: characteristic Y-shape. Whole specimens are necessary to confirm the identification. Type HA can be differentiated from the 6 thirdstage larval types belonging to the genus Terranova that have been adequately described by the relative lengths of the ventriculus and intestinal cecum. Four larval types, Type B of Koyama et al. (1969, Jap. J. Parasit. 18: 466-487) from Japan, Type I of Cannon (1977, Int. J. Parasit. 7: 233-243) from Queensland, type HB of Deardorff et al. (1982, loc. cit.) from the Hawaiian Islands, and T. secundum (as Porrocaecum s.) of Chandler (1935, Proc. U.S. Natn. Mus. 83: 123157) from Galveston Bay, Texas, have been described as possessing an intestinal cecum the same length as, or slightly longer than, the ventriculus. The 2 other larval types, Type II of Cannon (loc. cit.) and T. trichiuri (as Porrocaecum t.) of Chandler (loc. cit.) and Lent and Teixeira de Freitas (1948, Mems Inst. Oswaldo Cruz 46: 271), were described as having a cecum about twice as long as the ventriculus. Therefore, by possessing a cecum that is much shorter than the ventriculus, type HA larvae may be differentiated from these other types. We are grateful for the technical assistance of Robert A. Rychlinski in our laboratory and express our appreciation to the staff and management of Fishland Market, Ltd. and U. Okada and Co. for their cooperation during this study. This study was supported by Contract No. 22380-2295 from the Food and Drug Administration. . cit.) and T. trichiuri (as Porrocaecum t.) of
80 citations
TL;DR: Production of these clones established a well-defined serodeme that will allow detailed analysis of antigenic variation in African trypanosomes, and six of the 7 clones were distinct variants by immunological criteria using antisera derived from whole cells or purified surface glycoproteins.
Abstract: An extensive serodeme of sequentially-isolated antigenic variants of African trypanosomes has been produced from both syringe-passaged and cyclically-transmitted Trypanosoma brucei of the IsTaR 1 clone derived from EATRO 164. The majority of the antigenic variants were isolated from chronically-infected deer mice (Peromyscus leucopus). The pattern of parasitemias during the course of infections initiated with syringe-passaged trypanosomes differed from those initiated with cyclically-transmitted trypanosomes. Trypanosome populations from syringe-passaged (192) and cyclically-transmitted (31) clones were each amplified by growth in lethally-irradiated mice and cryopreserved for retrospective analysis. Five clones derived from a single deer mouse during the first 44 days of infection, and 2 clones derived from an acutely-infected rat were established from these amplified populations. Homogeneous populations were grown in lethally-irradiated rats and mice for antigenic analysis purification of variant-specific glycoprotein. Six of the 7 clones were distinct variants by immunological criteria using antisera derived from whole cells or purified surface glycoproteins. Two clones, one derived from the acutely-infected rat, and the other from the first parasitemia in a chronic infection that was initiated with the former clone, were immunologically identical. Production of these clones established a well-defined serodeme that will allow detailed analysis of antigenic variation.
76 citations
TL;DR: The data suggested that the susceptibilities of organisms to Sb within PEC and HM were generally comparable and that either amastigotes or viable promastigote-induced infections could be used to initiate the infection.
Abstract: Leishmania multiplying within either human monocyte-derived macrophages (HM) or mouse peritoneal exudate cells (PEC) have recently been shown to be susceptible to pentavalent antimony (Sb) by several investigators. The Sb susceptibilities of 5 cutaneous strains of Leishmania were compared in the 2 model systems, with infection of the macrophages initiated with either amastigotes or promastigotes. The susceptibility to Sb of amastigote-induced infections was statistically the same as the susceptibility of promastigote-induced infections for 4 strains in the PEC model, and for 3 of 4 strains in the HM model. Promastigote-induced infections with the 5th strain were non-viable in both macrophage types. The susceptibility of Leishmania to Sb within PEC was the same statistically as that of organisms within HM for amastigote-induced infections for 4 of 5 strains and for promastigote-induced infections by 3 of 4 strains. These data suggested that the susceptibilities of organisms to Sb within PEC and HM were generally comparable and that either amastigotes or viable promastigotes could be used to initiate the infection. The several technical advantages of the PEC model may make it more useful than the HM model for testing susceptibility to Sb. The modest susceptibility of some strains in both models to the peak serum amounts of antimony which may be achieved by presently recommended treatment regimes may partially explain the high current failure rate in simple cutaneous disease. The susceptibility of one strain within peritoneal cells to primaquine and WR 6026 (8-aminoquinolines), ketoconazole (an imidazole) and formycin B (an inosine analogue) was similar to that previously reported in human macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)
73 citations
TL;DR: The results suggest that prolongation of T.I. spiralis infection in w/wv mice is associated with delayed appearance of mast cells in the intestinal mucosa which may reflect slow generation of the intestinal inflammatory response.
Abstract: The intestinal mast cell response and lymphoblast activity, as measured by the incorporation of 3H-thymidine into mesenteric lymph node cells (MLN) of WBB6Fl-w/wv(w/wv) mice, their normal congenic littermates (+/+) and C57BL/6J mice, were compared after infection with Trichinella spiralis. Marked and similar blast cell activity and an increase in number of cells were observed in the MLN of infected w/wv and C57BL/6J mice 7 and 15 days P.I. In contrast to C57BL/6J mice, primary T. spiralis intestinal infections were prolonged in w/wv mice and more muscle larvae were recovered from w/wv mice 29 days post-infection. In C57BL/6J mice mucosal mast cell (MMC) numbers increased on day 7 P.I. whereas in w/wv mice these cells did not increase significantly until day 15 post-infection, reaching a peak on day 22. In w/wv mice, the response to secondary infection as determined by an accelerated expulsion of adult worms did not occur until day 11 postchallenge whereas in +/+ and C57BL/6J mice worm expulsion was nearly complete at that time. In both primary and secondary infections, the MMC numbers in w/wv mice were significantly lower than in C57BL/6J or +/+ mice. The results suggest that prolongation of T. spiralis infection in w/wv mice is associated with delayed appearance of mast cells in the intestinal mucosa which may reflect slow generation of the intestinal inflammatory response.
73 citations
TL;DR: Hatching, chemokinesis, and transformation of miracidia of Schistosoma mansoni were examined with a light microscope equipped with a video recording system and Parasites accumulated in a spot of serotonin by increasing their rate of turning.
Abstract: Hatching, chemokinesis, and transformation of miracidia of Schistosoma mansoni were examined with a light microscope equipped with a video recording system. Saline, linearly and reversibly, inhibited miracidial hatching and swimming. Both hatching and swimming were inhibited at 4 C and 12 C and accelerated at 34 C relative to rates at 22 C. Hatching was an explosive event that began with ciliary beating when the egg was placed in artificial pond water (APW) and culminated in the parasite's escape from the shell in 100 to 300 msec. Broken egg shells had sharp, complementary edges. Neither miracidia nor eggs swelled prior to hatching. Accumulation of miracidia in a spot of snail conditioned water (SCW) occurred rapidly due to a 60-75% decrease in the exit rate from the spot, rather than by an increase in the entry rate. The turning rate in SCW increased tenfold and the time spent in the spot was 6 times that of controls. Eserine sulfate inhibited miracidial turning and accumulation in SCW. Parasites accumulated in a spot of serotonin by increasing their rate of turning. Miracidia transformed to sporocysts in either complex media containing serum, RPMI-1640, Hanks' salts or phosphate buffered saline, but not in amino acids or vitamins. Transformation was inhibited when miracidia were incubated with serotonin or when miracidia had not been exposed previously to APW.
66 citations
TL;DR: Morel et al. as mentioned in this paper used an integrated biochemical approach in the identification of leishmania parasites from humans and canines in foci of cutaneous and visceral leishmaniasis.
Abstract: Leishmania parasites were isolated from humans and canines in foci of cutaneous and visceral leishmaniasis. After in vitro cultivation the parasites were examined by the following biochemical techniques: (i) restriction analysis of kinetoplast DNA (kDNA) also known as schizodeme analysis (Morel et al., 1980); (ii) zymodeme analysis (Barret et al., 1980); by agarose gel electrophoresis and (iii) isoelectricfocusing in polyacrylamide gels. The strains of cutaneous and visceralizing leishmanias studied could be differentiated by schizodeme analysis, using the endonuclease MspI, into three complexes agreeing with those accepted for human New World leishmaniasis. In the municipality of Rio de Janeiro, isolates from a focus of cutaneous leishmaniasis were identified as L. braziliensis braziliensis and from a focus of visceral leishmaniasis were identified as L. donovani by zymodeme characterization. Identical restriction enzyme profiles of kDNA from human and canine isolates indicated that in the cutaneous focus at Jacarepagua, Rio de Janeiro, the same strain was probably circulating in both the canine and human populations. This suggests a possible role for dogs as a reservoir host for L. braziliensis braziliensis. In addition, our results confirm the importance of dogs as reservoirs in visceral leishmaniasis. The stability of the electrophoretic patterns of restriction digest ("fingerprints") of Leishmania kDNA as well as differences in the sensitivity of the techniques used were demonstrated. Strains from widely different geographical areas as well as strains maintained in vivo and in vitro showed identical kDNA restriction patterns, while strains showing similar banding patterns by enzyme electrophoresis could be differentiated by schizodeme analysis. These results demonstrate the usefulness of an integrated biochemical approach in the identification of Leishmania.
66 citations
TL;DR: The results suggest that some lesions of lymphatic filariasis are potentially thymus-independent: lymphatic fibrosis, lymphangiectasis, accumulations of macrophages and giant cells around disintegrating worms, calcification of worms, intralymphatic thrombosis, and moderate vascular infiltrates including eosinophils.
Abstract: The nude (congenitally athymic) mouse, C3H/HeN is highly susceptible to infection with Brugia pahangi (Nematoda: Filarioidea). Normal, hairy mice show a strong thymus-dependent resistance and usually terminate the infection in the larval stages. The present study examined chronological histopathologic changes in the lumbar lymph nodes and adjacent lymphatic vessels of both hosts. In thymic mice, lymphangitis and perilymphangitis reached a maximum 14 to 17 days PI, about the time of disappearance of live worms. The infiltrate showed characteristics of both acute and chronic inflammation: eosinophils, neutrophils, eosinophilic precipitates, and sometimes necrotizing lymphangitis, as well as macrophages and plasma cells. The cellular infiltrate in nude mice was weaker and developed more slowly. Inflammatory responses to identifiable dead worms were seen in both types of hosts but appeared more frequently in thymic mice. Although variable in both models, the granulomas of thymic mice generally showed more tendency to cavitation, greater macrophage or epithelioid cell infiltration, more granulocytes, and appeared to be more destructive than the foreign body responses of nude mice. Whereas lymphangiectasis was generally progressive in nude mice, it was arrested before the end of the third week in thymic mice. In thymic mice, at maximum lumbar lymph node size (17 days), there were large areas of lymphocyte hyperplasia and heavy infiltration of plasma cells. Most nodes returned to normal mean size by the end of the second month. Little or no reactivity was seen in athymic mouse nodes. Our results suggest that some lesions of lymphatic filariasis are potentially thymus-independent: lymphatic fibrosis, lymphangiectasis, accumulations of macrophages and giant cells around disintegrating worms, calcification of worms, intralymphatic thrombosis, and moderate vascular infiltrates including eosinophils.
TL;DR: The in vivo assay for worm migrational responses suggests that the action of the neuromuscular stimulators and inhibitors on worm migration is indirect.
Abstract: Consistent in vitro behavioral patterns were found in the scolex and strobila of adult Hymenolepis diminuta. These patterns were measured with a force transducer and the behavior analyzed with a slow motion closed circuit T.V. Varying concentrations of serotonin (5-HT), acetylcholine (Ach), histamine and somatostatin, in the range of 10(-3) to 10(-9) M, were tested for their influence on the rhythmic patterns of behavior. High concentrations of 5-HT and of Ach decreased scolex motility. While 5-HT significantly increased motility in the anterior-, mid- and posterior regions of the strobila at 10(-3) M, Ach inhibited motility in all 3 regions of the strobila at the same concentrations. At high concentrations, somatostatin had a smaller stimulatory effect on worm motility in the anterior and mid-regions; histamine only significantly affected worm motility in the posterior region of the strobila. Depending on concentration, the action of 5-HT, Ach and histamine can be reversed, particularly in the anterior and posterior regions of the strobila. The in vivo assay for worm migrational responses suggests that the action of the neuromuscular stimulators and inhibitors on worm migration is indirect.
TL;DR: The demonstration of the variation of activity of the pyrimidine enzymes correlates with the increased synthesis of nucleic acids in the late trophozoite stage, providing a basis for the testing of the effectiveness of pyridine analogs as potential antimetabolites against various forms of the parasite.
Abstract: The 6 enzymes involved in de novo synthesis of pyrimidines were measured in Plasmodium falciparum isolated by saponin lysis from RBC's nonsynchronized and synchronized in vitro cultures. The total activities were found to be dependent on the stage of the P. falciparum cycle. In parasites isolated from synchronized cultures, the highest activities for all enzymes were found at about 27 hr after synchronization in the late trophozoite stage, or just before schizont formation. Merozoites and ring forms contained little de novo activity. The first enzyme of the pathway, carbamyl phosphate synthetase (CPS-II) preferentially utilized glutamine. Ammonia was a poor substrate. CPS-II was unstable in the absence of the cryoprotectants, dimethylsulfoxide and glycerol. The apparent Km for MgATP--was 3.8 +/- 0.7 mM and the enzyme in all morphological forms of P. falciparum (ring, mature trophozoites and schizonts) was inhibited by UTP. The activity of the fourth enzyme of the pathway, dihydroorotate dehydrogenase, appeared to be linked to the cell's respiratory chain; inhibitors of mammalian electron transport such as cyanide, amytal, antimycin A, thenoyltrifluoroacetone and ubiquinone analogs also inhibited the P. falciparum enzyme. The demonstration of the variation of activity of the pyrimidine enzymes correlates with the increased synthesis of nucleic acids in the late trophozoite stage. These observations provide a basis for the testing of the effectiveness of pyrimidine analogs as potential antimetabolites against various forms of the parasite.
TL;DR: The studies showed a dose-related, transient reticulocytopenia as the major manifestation of an altered peripheral erythrocytic profile of mice infected with T. spiralis and established that this hematological event coincided with the intestinal phase of the disease and attribute it to the vascular insult that occurs during this period.
Abstract: et al., 1952, J. Elisha Mitchell Scientific Soc. 68: 1-11; Larsh and Race, 1954, J. Inf. Dis. 94:262273). The similar peripheral blood patterns manifested by the three infected groups indicated the occurrence of the same pathogenic events during this interval. These data also suggest that the intensity of the damage to the intestinal milieu inflicted simultaneously by migrating larvae and adult worms is proportional to the size of the infecting dose. The observation of no significant decreases in the Hb amounts and total numbers of RBC's in Group I throughout the duration of the experiment is evidence that the bleeding regimen was not responsible for the hematological findings. The damage inflicted to the host during the intestinal phase of trichinellosis occasions diffused punctate hemorrhages that would account for the reticulocytopenia and other erythrocytic findings reported here. The occurrence of reticulocytosis in the three groups beginning after day 15 (Fig. 1C) expresses the operation of rest al., 1952, J. Elisha Mitchell Scientifi Soc. 68: torative activities functioning to compensate for the blood loss in excess of that removed for making hematological measurements. Erythropoietic activity in the blood forming organs was confirmed by the concurrent increases in the blood Hb amounts and total RBC counts (Fig. 1A, B). Our studies showed a dose-related, transient reticulocytopenia as the major manifestation of an altered peripheral erythrocytic profile of mice infected with T. spiralis. We established that this hematological event coincided with the intestinal phase of the disease and attribute it to the vascular insult that occurs during this period. Reticulocytopenia is reported as a new finding in trichinella infection. Supported by Biomedical Research Support Grant No. 2S07RR05413 (Hahnemann University School of Medicine). Statistical analysis by D. G. McGee (Villanova University Computing and Information Services) is acknowledged. i i c e sate for
TL;DR: The hypothesis that heterogeneity within theHost population, rather than across the collective host population, is the main factor generating overdispersion in natural populations was confirmed and was confirmed for 3 of 10 helminth species.
Abstract: The effects of selected intrinsic variables operating on host subpopulations and of extrinsic variables across the collective host population on the distributions of 10 common helminth species from coyotes in south Texas were compared. The intrinsic variables of host sex and presence and severity of sarcoptic mange had little effect on the distributions of most helminth species. The combined influences of (1) seasonal changes across the collective host population and (2) host subpopulations delineated by age were responsible for the overdispersed distributions of Oncicola canis, Physaloptera rara, and Protospirura numidica. Overdispersion in Ancylostoma caninum, Alaria marcianae, and Spirocerca lupi populations resulted almost exclusively from the heterogeneity of factors contributing to their rates of establishment, survival, and reproduction as generated across host age subpopulations. Aggregated abundances of A. caninum and A. marcianae occurred in young hosts, but were cumulative in older animals infected with S. lupi. The hypothesis that heterogeneity within the host population, rather than across the collective host population, is the main factor generating overdispersion in natural pop- ulations was confirmed for only 3 of 10 helminth species (A. caninum, A. marcianae, and S. lupi). The effects of extrinsic factors operating across the collective host population appeared to be equal to, or in some instances of greater importance than, these forces operating over host subpopulations in determining the dispersion patterns of some helminth species (0. canis, P. rara, and P. numidica). The distributions of Taenia pisiformis, Meso- cestoides lineatus, Oslerus osleri, and Toxascaris leonina were not affected, or only minimally influenced, by these intrinsic or extrinsic variables. The effects of these habitat variables on dispersion patterns are highly correlated with the life cycle and mode of transmission of the respective helminth species.
TL;DR: In this chapter the problem of general paralysis is described, the manner and effects of malariatherapy, and the knowledge gained for malariology are described.
Abstract: Medicine offers few examples of a living pathogen that is therapeutic in a disease caused by another. Nevertheless, the malaria parasites, some scourges themselves, were used for about 40 years to ameliorate or reverse the ravages of neurosyphilis, a life-threatening advanced phase of syphilis. Furthermore, in using malariatherapy invaluable information was gained-as it might not otherwise have been gained-about the biology of malaria, its treatment, and its mosquito transmission. Truncated versions of the origins and uses of malariatherapy appear in the introductions to older papers and books, and more extensively in a now-rare monograph by Kupper (1939), in an excellent clinically oriented book by Moore (1941), and in an informative chapter by Becker (1949). The advent of penicillin in the mid1940's ineluctably signalled the end of malariatherapy for syphilis, but, as suggested by the title of an editorial on that subject (Anon., 1975), the 'final curtain' did not come down on malariatherapy in Britain until the 1970's, and combined therapy with penicillin and malaria, once common in the United States (Crawford, 1948; Becker, 1949), ceased in the mid1960's. I plan to describe in short compass the problem of general paralysis, the manner and effects of malariatherapy, and the knowledge gained for malariology. Only one or two generations ago syphilis and malaria were important to each other, but to this day the biological interactions between the two organisms remain largely unexplained.
TL;DR: First-stage larvae of Parelaphostrongylus odocoilei and P. tenuis and their infectivity to the snail Triodopsis multilineata were determined experimentally in a variety of temperature and moisture conditions and survival increased with decreasing temperature, while infectivity was greatly reduced.
Abstract: The survival of first-stage larvae (L1) of Parelaphostrongylus odocoilei and P. tenuis (Nematoda: Metastrongyloidea) and their infectivity to the snail Triodopsis multilineata were determined experimentally in a variety of temperature and moisture conditions. Survival of larvae of P. odocoilei increased with decreasing temperature. Survival of larvae in water was similar to survival in air at 17 and 45% RH; survival of larvae in air at 75, 85, and 95% RH was considerably lower at corresponding temperatures. The infectivity of larvae of P. odocoilei that survived desiccation was greatly reduced. Repeated freezing or repeated desiccation resulted in reduced survival of P. odocoilei and P. tenuis. Larvae of Parelaphostrongylus odocoilei from mule deer of Jasper National Park, Canada, were better able to resist the effects of freezing, but less able to resist the effects of desiccation, than were larvae of P. tenuis from white-tailed deer of Pennsylvania, USA.
TL;DR: It is indicated that skin EFA and PG may have a critical role in the completeness of penetration by cercariae through the skin, although it is not clear whether cercarial or host PG are involved in the penetration response.
Abstract: We used rat skin membranes to test the putative role of prostaglandins (PG) and essential fatty acids (EFA) in the penetration response of Schistosoma mansoni cercariae. To examine the effects of EFA on cercarial penetration an EFA-deficient rat model was used. Dams were fed an EFA-deficient diet during lactation and the pups were weaned to this diet. Cercarial penetration of EFA-deficient rat skin membranes was not reduced from control levels until 12 wk on the diet. At this time a decrease of 64.3% was observed. This decrease remained constant up to 16 wk, after which the study was terminated. Other normal rats were treated with 20 mg/kg ibuprofen, a PG inhibitor, to examine the role of PG in the penetration response. Treated rat skin contained a mean of 2 ,g ibuprofen per 30 mm3 of skin (25-mm skin disc) at 1.5 hours post-injection. Skin from treated rats inhibited penetration by over 81%. These studies indicate that skin EFA and PG may have a critical role in the completeness of penetration by cercariae through the skin, although it is not clear whether cercarial or host PG are involved in the penetration response.
TL;DR: Trypanosomes isolated from all species of susceptible fishes were infective to goldfish, and samples from goldfish clustered into a tight group while those from the other fishes formed a loose cluster along the first canonical axis.
Abstract: Carassius auratus, Barbus conhus, Danio malabaricus, Catostomus commersoni, Notropis cornutus, Etheostoma caeruleum, and Ictalurus nebulosus were susceptible to Trypanosoma danilewskyi by intraperitoneal inoculation. Trypanosomes isolated from all species of susceptible fishes were infective to goldfish. No try- panosomes were detected in inoculated Semotilus atromaculatus, Ambloplites rupestris, Lepomis gibbosus and Percaflavescens. Fifty specimens were measured from each of 3 C. auratus, 2 B. conhus, 2 C. auratus inoculated with an isolate from a C. commersoni, 2 C. commersoni, and 2 E. caeruleum, for statistical analyses. The distance of the kinetoplast from the posterior end, length of free flagellum, nuclear length, and area of nucleus were similar among samples from the same host but differed significantly among samples from different host species. After discriminate analysis, samples from goldfish clustered into a tight group while those from the other fishes formed a loose cluster along the first canonical axis. Using the jacknife method of correct classification, 93% of trypanosomes from C. auratus, 36% from C. commersoni, 61% from C. commersoni-C. auratus, 25% from B. conhus, and 40% from E. caeruleum, could be correctly assigned to host species. However, only 1% of trypanosomes from C. commersoni would be classified as coming from C. auratus, 4% for C. commersoni-C. auratus, 0% for B. conhus, and 7% for E. caeruleum.
TL;DR: Intact proglottids or excised paruterine organs (PO) were processed by standard techniques for TEM and SEM, and some differences in embryonic envelopes presumably were associated with containment of all eggs in the PO which may eliminate the need for individual protective shells.
Abstract: Mesocestoides lineatus tetrathyridia were removed from the body cavity of lizards, Anolis caroli- nensis, and fed to hamsters in which they developed to adults. Gravid proglottids were taken from feces for study. Intact proglottids or excised paruterine organs (PO) were processed by standard techniques for TEM. For SEM, PO contents were exposed by subjecting whole proglottids to freon cryofracture or sectioning in Paraplast. Gravid PO's were thick-walled with enclosed eggs distributed throughout a cellular matrix. The wall was of parenchymal origin, containing muscle bundles and various cellular products. Each egg consisted of an oncosphere enclosed by a double-unit oncospheral membrane and a syncytial cytoplasmic envelope containing an embryo- phore. A discrete outer envelope and capsule were absent. Eggs were separated by PO matrix cells with prominent nuclei, mitochondria, intercellular junctions, and much extracellular material. These matrix cells may be related ontogenetically to individual eggs and thus homologous to embryonic envelope cells normally lying outside the embryophore of other cyclophyllids. Some differences in embryonic envelopes presumably were associated with containment of all eggs in the PO which may eliminate the need for individual protective shells. Other components of the PO matrix such as large reticular bodies are of unknown significance.
TL;DR: A major role for prostaglandins is postulated in the cercarial penetration response after an inhibition of this response by ibuprofen and aspirin and by 13-azaprostanoic acid, a potent antagonist of the thromboxane/endoperoxide receptor.
Abstract: In examining the structure-activity relationship of a diverse group of chemicals reported to prevent cercarial penetration after topical application, we noticed a moiety that was common to free fatty acids and prostaglandins. Because unsaturated fatty acids have been reported to stimulate cercarial penetration, we hypothesized that cercarial stimulation by skin and fatty acids may invoke prostaglandin mechanisms in cercariae, skin, or both. Thus we compared the stimulation of cercariae by a series of essential and nonessential fatty acids and demonstrated an inhibition of this response by ibuprofen and aspirin, known cyclo-oxygenase inhibitors, and by 13-azaprostanoic acid, a potent antagonist of the thromboxane/endoperoxide receptor. These data led us to postulate a major role for prostaglandins in the cercarial penetration response.
TL;DR: Different Pacific salmon stocks from British Columbia demonstrated differences in susceptibility to C. salmositica in experimental studies using laboratory reared juvenile fish, believed to be associated with innate, genetically transmitted resistance.
Abstract: The haematocrit centrifugation technique, modified by keeping the haematocrit tubes cold (between 1 and 10 C), was sensitive for detecting light infections of Cryptobia salmositica (as few as 75 flagellates per ml of blood). In wet mount preparations, infections lighter than 7.5 X 10(3) flagellates per ml of blood could not be detected consistently. Different Pacific salmon stocks from British Columbia demonstrated differences in susceptibility to C. salmositica in experimental studies using laboratory reared juvenile fish. Oncorhynchus keta and Oncorhynchus tshawytscha from the Big Qualicum River stocks (Vancouver Island), and Oncorhynchus nerka from the Fulton River stock (Skeena River system), were all equally susceptible and suffered high mortalities at low exposures (100 flagellates in 0.1 ml physiological saline inoculated intraperitoneally per fish). Oncorhynchus nerka from the Weaver Creek stock (Fraser River system) was the most resistant with no mortalities even at exposures of 10(6) flagellates (in 0.1 ml physiological saline) per fish. Oncorhynchus kisutch seemed to be slightly less resistant than the Weaver Creek O. nerka, but fewer than 16% of the inoculated fish died. Oncorhynchus kisutch from the Big Qualicum River seemed to be slightly more resistant than O. kisutch from the Capilano River stock (a coastal river near Vancouver), with fewer mortalities and lighter infections when the experiments were terminated. Differences in susceptibility are believed to be associated with innate, genetically transmitted resistance.
TL;DR: At least 5 morphologically distinct types of sensory receptors are present in the tegument of mature Cotylogaster occidentalis and may function to detect stresses associated with muscular contractions.
Abstract: At least 5 morphologically distinct types of sensory receptors are present in the tegument of mature Cotylogaster occidentalis. The different types of sensilla were distinguished by the presence or absence of sensory cilia, the morphology of the rootlets, the mechanisms of attachment to the tegument and the distribution in the body. Sensory receptors were concentrated near the buccal funnel and oral opening. They were also present in the ventral haptor, but were rare in the dorsal tegument. The Type I sensillum is the only type which extended through the thickness of tegument and had a free sensory cilium. Sensory receptors of this type may be either chemo- or mechanoreceptive in function. Four of the types (II to V) were nonciliated, entirely intrategumental in location, and were probably mechanoreceptors. The Type II sensillum contained a disk-shaped, striated rootlet and was found only on the alveolar ridges of the ventral haptor. The morphology and characteristic location of this type of receptor suggested that it might mediate in the function of the ventral haptor. Types III and IV sensilla were similar in general morphology but differed in their mode of attachment to the tegument and in the appearance of their rootlets. The subtle ultrastructural differences in the Types III and IV rootlets probably reflect physiological specializations of response to different stimuli. The Type V sensillum contained an elongate, striated rootlet and was located in deep invaginations of the tegument. They were surrounded by circular and longitudinal muscles which formed numerous hemidesmosomes with the basal lamina encircling the receptors. Sensory receptors of this type may function to detect stresses associated with muscular contractions.
TL;DR: Since both urchins are commonly found in close proximity to each other in beds of Thalassia, and apparently feed on the same materials, there may be physiological differences which account for the host-parasite specificity of L. variegatus.
Abstract: which was always found in large numbers in each of the study sites occupied by infected L. variegatus. Since both urchins are commonly found in close proximity to each other in beds of Thalassia, and apparently feed on the same materials, there may be physiological differences which account for the host-parasite specificity. Unforwhic was always found in arge numbers in each tunately, nothing is known about the life cycles of species of Syndesmis. Although it would appear the parasites and/or their eggs could pass from the host intestine with the feces, it is not known how they could pass from the coelomic cavity of the host to the exterior. Future comparative studies of the physical, chemical and biological features of the back-reef areas may provide information helpful to our understanding of the life cycle of this parasite. Also, it would be of interest to examine urchins from other bays which have similar characteristics to those of Discovery Bay to determine if the parasite exhibits a restricted distribution in these areas. We wish to thank Dr. Donald W. Duszynski of the Department of Biology at the University of New Mexico, Albuquerque, New Mexico, for reading the manuscript and providing helpful comme ts. We thank the following individuals who helped with the collections: C. Ennesser, C. Reich, A. Mucerino, M. Macuga, K. Lamminen, S. Cowie, B. Merrill, and W. Way. Contribution number 325 from the Discovery Bay Marine Laboratory, University of the West Indies.