James R. Coggins

Giardia cyst wall-specific carbohydrate: evidence for the presence of galactosamine

Gas chromatographic (GC), mass spectrometric (MS), lectin binding and enzymatic analyses of the carbohydrates from Giardia cyst walls, intact cysts and trophozoites were performed to investigate the carbohydrate composition of Giardia cyst walls and to test the hypothesis that the Giardia cyst wall is composed largely of chitin. Galactosamine, verified by MS, was present in Giardia cyst walls and intact cysts (ca. 47 nmol 10(-6) cysts). Since not even trace amounts of it were detected in trophozoites by either GC or lectin binding, galactosamine is hypothesized to be a cyst wall-specific amino hexose. Based on the putative binding affinity of Phaseolus limensis lectin, galactosamine may be present in cyst walls as N-acetylgalactosamine. Neither glucosamine nor sialic acid were detected in as much as 11 mg dry weight of cysts, cyst walls, or trophozoites. Glucose, the most abundant carbohydrate, and ribose were detected in Giardia cysts and trophozoites. Galactose (ca. 10 nmol 10(-6) cysts) was detected in cysts but not in trophozoites. The lack of detectable levels of (1) glucosamine in cyst wall hydrolysates, (2) cyst staining by Calcofluor M2R, (3) endogenous chitinase activity and (4) N-acetylglucosamine when cysts served as a substrate for exogenous chitinase suggests that the Giardia cyst wall is not composed largely of chitin as previously reported. beta-N-Acetylgalactosaminidase, EC 3.2.1.32, activity was detected in cysts and trophozoites and represents the first carbohydrate splitting hydrolase detected in Giardia.

Helminth community structure of sympatric eastern American toad, Bufo americanus americanus, northern leopard frog, Rana pipiens, and blue-spotted salamander, Ambystoma laterale, from southeastern Wisconsin.

One-hundred twelve amphibians, including 51 blue-spotted salamanders, Ambystoma laterale, 30 eastern American toads, Bufo americanus americanus, and 31 northern leopard frogs, Rana pipiens, were collected during April–October 1996 from Waukesha County, Wisconsin and examined for helminth parasites. The helminth compound community of this amphibian assemblage consisted of at least 10 species: 9 in American toads, 8 in leopard frogs, and 3 in blue-spotted salamanders. American toads shared 7 species with leopard frogs, and 2 species occurred in all 3 host species. Although there was a high degree of helminth species overlap among these sympatric amphibians, statistically significant differences were found among host species and percent of indirect or direct–life cycle parasites of amphibian species individual component communities (χ2 = 1,015, P < 0.001). American toads had a higher relative abundance of nematodes, 59%, than larval cestodes, 31%, and larval and adult trematodes, 10%, whereas leopard frogs had a higher relative abundance of larval cestodes, 71.3%, and larval and adult trematodes, 25.3%, than nematodes 3.4%. This is related to ecological differences in habitat and dietary preferences between these 2 anuran species. Helminth communities of blue-spotted salamanders were depauperate and were dominated by larval trematodes, 94%, and few nematodes, 6%. Low helminth species richness in this host species is related to this salamanders relatively small host body size, smaller gape size, lower vagility, and more fossorial habitat preference than the other 2 anuran species. Adult leopard frogs and toads had significantly higher mean helminth species richness than metamorphs, but there was no significant difference in mean helminth species richness among adult and metamorph blue-spotted salamanders. Considering adult helminths, the low species richness and low vagility of caudatans as compared with anurans suggest that local factors may be more important in structuring caudatan helminth communities of salamanders than of anuran hosts. Helminth species infecting salamanders may be more clumped in their geographic distribution as compared with anurans, and the role of other hosts and their parasites at the compound community level may be important in structuring helminth communities of salamanders.

HELMINTH COMMUNITIES IN FIVE SPECIES OF SYMPATRIC AMPHIBIANS FROM THREE ADJACENT EPHEMERAL PONDS IN SOUTHEASTERN WISCONSIN

Representatives of 5 amphibian species (313 individuals), including eastern American toads (Bufo americanus), wood frogs (Rana sylvatica), spring peepers (Pseudacris crucifer), blue-spotted salamanders (Ambystoma laterale), and central newts (Notophthalmus viridescens louisianensis), were collected from 3 ephemeral ponds during spring 1994, and they were inspected for helminth parasites. The component communities of anurans were more diverse than those of caudates. Infracommunities of all host species were isolationist and depauperate, due mostly to host ectothermy and low vagility. Toad infracommunities were dominated by skin-penetrating nematodes, and they had the highest values of mean total parasite abundance, mean species richness, and overall prevalence. This was likely due to their greater vagility compared with other host species. Infracommunities of wood frogs and blue-spotted salamanders had intermediate values for these measures of parasitism, whereas spring peeper and newt infracommunities had the lowest values. In addition to relative vagility, feeding habits and habitat preference were likely important in helminth community structure. Body size also seemed to play a role because mean wet weight of host species followed the same general trend as values of parasitism. However, effects of size were variable within host species and difficult to separate from other aspects of host ecology.

Seasonal Changes and Overwintering of Parasites in the Bat, Myotis lucifugus (Le Conte), in a Wisconsin Hibernaculum

During 1979-1980, eight digenetic trematode species, one cestode species and three nematode species were recovered from the little brown bat (Myotis lucifugus) at a southeastern Wisconsin hibernaculum. Statistically significant seasonal variation was observed for two digenetic trematodes. Mean densities and prevalence (%So of hosts infected) of parasites were highest in autumn and spring and lowest in summer. Highest species number occurred in autumn. Greater density and prevalence in autumn and spring may be correlated with bat swarming and emergence patterns, behavioral phenomena which would also produce a more heterogeneous assemblage of parasites during these times of the year. Myotis lucifugus retained high densities and prevalence of parasites throughout 8 months of hibernation.

Spatial Ecology and Habitat Selection of Bullsnakes (Pituophis catenifer sayi) at the Northern Periphery of Their Geographic Range

Abstract Bullsnakes (Pituophis catenifer sayi) have been the subject of few rigorous scientific investigations despite suspected declines. Because relatively little ecological information exists for this species, sound conservation or management decisions regarding them are difficult to make. This is particularly true in the upper Midwest, which represents the northern periphery of the snakes geographic range. Using radio-telemetry, we studied aspects of the ecology of Bullsnakes (15 males, 12 females) in Sauk County, Wisconsin, which included determining habitat preferences and movement patterns. Male and female Bullsnakes exhibited a preference for open bluff sides over habitats traditionally reported as favored by this species (i.e., sand prairies or grasslands), and avoided areas of agriculture and closed canopy bluff side forest. Nested ANOVA analysis of home ranges measured as 100% minimum convex polygons (23 ha females, 41 ha males) and 95% kernels (53 ha females, 83 ha males) were larger in males than females. Average daily movement rates were larger in males (31.7 m females, 36.7 m males). Evidence of site fidelity was also found. Based on these results, the conservation of this snake can be substantially influenced by preservation and maintenance of large sites containing open bluffs and oak savannas.

SEASONAL OCCURRENCE, MORPHOLOGY, AND OBSERVATIONS ON THE LIFE HISTORY OF GORDIUS DIFFICILIS (NEMATOMORPHA: GORDIOIDEA) FROM SOUTHEASTERN WISCONSIN, UNITED STATES

A total of 584 adult nematomorphs, Gordius difficilis, was collected from 2 man-made ponds and their overflow stream in southeastern Wisconsin. Ponds were surveyed throughout the year, but all free-living worms were found during July–August of 1996, July–September of 1997, and June–August of 1998. Overall sex ratio was male biased; however, sex ratio was variable during different months. Observations during 1998–2000 indicated that worms mated within 24–48 hr of emergence from their hosts and began laying eggs by mid-August, continuing until mid-October. Eggs with well-developed larvae were recovered during October and November. Encysted larval nematomorphs were recovered from aquatic and semiaquatic invertebrates (gastropods, earthworms, and insects), whereas developing hairworms were found in terrestrial European ground beetles Pterostichus melanarius. It is hypothesized that semiaquatic invertebrates may serve as intermediate/paratenic hosts in this system and are preyed upon by terrestrial carabid beetles, thus completing the life cycle. In addition, scanning electron microscopy observations of G. difficilis add previously unreported observations on intraspecific variation in body length, cuticle morphology, and gametes of this species. This is the first report of G. difficilis from Wisconsin as well as the first report of this species from P. melanarius and aquatic and semiaquatic invertebrates.

Observations on Myiasis by the Calliphorid, Bufolucilia silvarum, in the Eastern American Toad (Bufo americanus americanus) from Southeastern Wisconsin

Larvae of certain species of blowflies (Calliphoridae) cause myiasis in amphibians which may result in significant mortality, yet there are few reports from North America. In this study, we observed primary myiasis in a population of juvenile eastern American toads (Bufo americanus americanus) collected during May–July 1998 from southeastern Wisconsin (USA). Nine (6%) of 140 toads were infected by the green blow fly (Bufolucilia silvarum) with a mean intensity of 10.5±7.2 (range=1–24). Weekly parasite prevalence and mean intensity remained low, ranging from 0–20% and 2±1.4 to 14±6, respectively. We found: 1) flies lay eggs on healthy toads, 2) eggs hatch with first instar maggots penetrating under the skin, 3) maggots develop to mature third instars within 5–7 days, 4) maggots leave the host and form pupa within 8–11 days of hatching, and 5) maggots pupate within 7–9 days at room temperature. All infected toads died within 1–2 wk as a result of the infection. The low prevalence observed in this study and other reports of this species from mammalian and bird carcasses indicated that B. silvarum is probably a facultative parasite of toads and other amphibians in the United States. This is the first report of B. silvarum causing myiasis in Wisconsin amphibians and the first report in eastern American toads in the United States.

Giardia muris: scanning electron microscopy of in vitro excystation

A recently developed in vitro excystation procedure results in almost total excystation of Giardia muris, an intestinal parasite of mice. The present experiment examines the G. muris cyst morphology by scanning electron microscopy and the efficacy of the excystation procedure. Untreated cysts of G. muris were elliptical and displayed a distinctive surface structure. Excystation began almost immediately after incubation had begun and most trophozoites emerged within 30 min. Excystation appears to involve flagellar action of the encysted trophozoite. A tear of the wall occurred at one pole. This opening was subsequently enlarged, presumably by flagellar action. Trophozoites emerged, posterior end first, and an associated mucoid-like material was extruded. Newly emerged trophozoites were nearly oval in shape. Trophozoites quickly became flattened, elongate, and underwent cytokinesis resulting in two daughter trophozoites. Few organisms not excysted were seen after 30 min incubation.

Tegument and apical end organ fine structure in the metacestode and adult Proteocephalus ambloplitis.

Abstract The tegument of plerocercoid and adult P. ambloplitis was examined. Differences in tegument structure existed between these two stages. Plerocercoids of P. ambloplitis lacked extensive vacuolization and unicellular gland cells characteristic of adult tegument. Plerocercoid microtriches were short and conoid; adult microtriches were lenticular with an extended, whip-like shaft. An inclusion, not previously reported from proteocephalid cestodes, is described. Adult tegument had ducts, originating from underlying unicellular glands, extending through the distal cytoplasm and opening to the exterior between microtriches. The apical end organ cavity of P. ambloplitis contained numerous labyrinth-like spherical bodies. These structures appeared to be synthesized and secreted into the end organ by a thin cellular lining of the end organ. This lining was composed of discrete, filamentous cells believed to be modified subtegumental cell bodies. Spherical structures identical to those observed within the end organ cavity occurred within this cellular lining. The spherical bodies may be associated with enzymes necessary for tissue migration by the metacestode.

Electron microscopy of the tumulus and origin of associated structures within the tegument of Eubothrium salvelini Schrank, 1790 (Cestoidea: Pseudophyllidea)

Abstract Tedesco J. L. and Coggins J. R. 1979. Electron microscopy of the tumulus and origin of associated structures within the tegument of Eubothrium salvelini Schrank, 1790 (Cestoidea: Pseudophyllidea). International Journal for Parasitology 10 : 275–280. Validity of the tumulus, a new organ recently described on the tegument of Eubothrium salvelini , is confirmed. Spherical, dense inclusions approximately 0.23–0.29 μm were associated with the tumulus and with subtegumental cell bodies. Origin of these inclusions within subtegumental cell bodies and their transport via ducts to the tumulus is described. Inclusions are synthesized within granular endoplasmic reticulum and packaged by Golgi apparatus prior to transport. Inclusions were observed only in association with the tumulus within the tegumental distal cytoplasm.