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S S Desser

Publications and source records attributed to S S Desser.

At least 19 recordsLinked to original sources
PubMed2001

The blood parasites of anurans from Costa Rica with reflections on the taxonomy of their trypanosomes.

During May 1997, specimens of 7 species of anurans, that included 5 Phrynohyas venulosa Laurenti, 5 Rana forreri Boulenger, 7 Rana vaillanti Brucchi, 6 Eleutherodactylus fitzingeri Schimdt, 4 Smilisca baudinii Duméril and Bibron, 1 Leptodactylus melanonotus, and 3 Bufo marinus Linneaus, from the Guanacaste Conservation Area, Costa Rica were examined for blood parasites. Their hematozoan fauna included intraerythrocytic and intraleukocytic icosahedral viruses, a rickettsia (Aegyptianella sp.), 2 species of Hepatozoon, Lankesterella minima, 2 unknown species of apicomplexans, 9 morphologically distinct types of trypanosomes, and 2 species of microfilariae. Rana vaillanti, the most aquatic species of frog, harbored the most species of parasites. Recent evidence indicates that morphological changes in the highly pleomorphic trypanosomes of anurans from different geographical regions have not kept pace with biochemical (isozyme) and molecular (DNA sequence) changes. Describing new species based solely on bloodstream trypomastigotes is discouraged. Additional criteria described herein should be applied when naming new species of anuran trypanosomes.

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PubMed2001

Transmission of Haemogregarina balli from painted turtles to snapping turtles through the leech Placobdella ornata.

Six leeches (Placobdella ornata) were allowed to feed on a painted turtle (Chrysemys picta marginata) infected with Haemogregarina balli and subjected to a period of diapause before being allowed to feed on 2 laboratory-reared snapping turtles (Chelydra serpentina). Weekly examination of thin blood films revealed infections of the turtles at 130 days postfeeding. These observations provide support for broad host specificity of hemogregarine parasites of chelonians.

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PubMed2000

Cladistic analysis of myxozoan species with known alternating life-cycles.

The phylogenetic relationships of 15 myxozoan taxa with known alternating life-cycles were investigated in order to provide insight into the puzzling matches between myxosporeans and actinosporeans of the myxozoan life-cycle data. Phylogenetic analyses were performed using two partitioned data-sets of life-cycle stages, myxosporean stage from fish hosts versus actinosporean stage from annelid hosts, and a combined data-set of myxosporean and actinosporean stages. A cnidarian parasite of fish, Polypodium hydriforme Ussov, 1885, was used as the outgroup. The supraspecific level grouping in the conventional classification of actinosporeans was not supported in the analysis of the partitioned data from the actinosporean phase, which yielded two equally parsimonious trees. Analysis of the partitioned data from the myxosporean phase provided 24 equally parsimonious trees and did not support the current classification of myxosporeans. The analyses of the partitioned data of myxozoans by life-cycle stage revealed a lack of taxonomic congruence between the two life-stage partitions. Two equally parsimonious trees were obtained from analysis of the combined data. The suborder Variisporina of the Myxozoa was not supported by the total evidence trees, while the monophyly of the species of Myxobolus Butschli, 1882 and of the Myxidiidae were supported. The cladograms from the combined data revealed that these myxozoan species formed four major monophyletic groups. Among them, two were supported by the partitioned data of the actinosporean phase. The phylogenetic signals and the better resolution reflected by the trees of combined data suggest that the phylogenetic total evidence approach should be employed in future studies of the systematics of myxozoans.

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PubMed2000

The longevity of actinosporean spores from oligochaetes of Lake Sasajewun, Algonquin Park, Ontario, and their reaction to fish mucus.

The longevity of 7 forms of actinosporean spores and the reaction of 6 forms of actinosporeans to fish mucus were investigated. The maximum longevity of actinosporean spores kept at ambient laboratory temperatures was 14 days. Spore longevity ranged from 11 to 14 days among actinosporeans. The reaction of spores to fish mucus varied among the actinosporeans. Triactinomyxon F of Xiao and Desser, 1998 reacted only to the mucus of the common shiner Luxilus cornutus, and golden shiner Notemigonus crysoleucas, whereas the aurantiactinomyxon form of Xiao and Desser, 1998, and raabeia B of Xiao and Desser, 1998 reacted readily to mucus of all fish species tested. The differences in reaction to fish mucus among actinosporeans may indicate their different host range. These results indicate that actinosporean spores are short-lived and that actinosporeans respond to their hosts by chemodetection.

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PubMed2000

Intraerythrocytic development of species of Hepatozoon infecting ranid frogs: evidence for convergence of life cycle characteristics among apicomplexans.

Intraerythrocytic development of the adeleorin apicomplexans Hepatozoon clamatae and Hepatozoon catesbianae were investigated in the bullfrog, Rana catesbeiana, the green frog, Rana clamitans melanota, and the Northern leopard frog, Rana pipiens. Merozoites emerging from hepatic meronts penetrated erythrocytes and underwent 1-3 rounds of binary fission to produce 2-8 merozoites. Following their release from infected erythrocytes, individual merozoites entered new cells and transformed into gamonts. Although this is the first report of intraerythrocytic development for a fully described species of Hepatozoon, a phylogenetic reanalysis of 11 species of Hepatozoon, 6 species representative of the 5 other hemogregarine taxa, 2 species of dactylosomatids, and 2 species of piroplasms, indicates that asexual reproduction of parasites within blood cells of vertebrates has arisen at least 3 times in the apicomplexan lineage that includes adeleorins and piroplasms. This method of asexual development, which is also observed in species of hemospororin genera such as Plasmodium, is discussed in the context of the evolution of apicomplexan life cycles. In addition to supporting the paraphyly of the genus Hepatozoon determined in an earlier study, this phylogenetic analysis featured a monophyletic group, consisting of the sister taxa Hemolivia and Karyolysus, that was the sister group to a clade consisting of the more derived hemogregarines, the dactylosomatids, and the piroplasms.

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PubMed1999

Phylogenetic relationships among Hepatozoon species from snakes, frogs and mosquitoes of Ontario, Canada, determined by ITS-1 nucleotide sequences and life-cycle, morphological and developmental characteristics.

The molecular biological characteristics of Hepatozoon species infecting various species of snakes, frogs and mosquitoes were investigated by determining the nucleotide sequences of the first internal transcribed spacer region. A phylogenetic analysis was performed on seven isolates of Hepatozoon infecting snakes, including Hepatozoon sipedon and four morphologically similar but not identical forms, and two isolates of Hepatozoon catesbianae infecting Green frogs (Rana clamitans melanota). This analysis, which utilised data from first internal transcribed spacer nucleotide sequences, morphological and morphometric features of gamonts, oocysts and sporocysts, and previously determined life-cycle and host-specificity characteristics, revealed that H. sipedon is a polymorphic species with a wide host and geographic range. Four synapomorphies. including two nucleotide substitutions and two morphological character state changes, supported a monophyletic group of six isolates of H. sipedon from the central region of Ontario which was the sister group for an isolate (HW1) from the southern part of the province. Based on the results of this study, an evaluation of which criteria are useful for describing species of Hepatozoon is presented, with the intent of curtailing the practice of naming species based on morphological features of gamonts or on incomplete life-cycle data.

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PubMed1998

The life history and host specificity of Hepatozoon clamatae (Apicomplexa: Adeleorina) and ITS-1 nucleotide sequence variation of Hepatozoon species of frogs and mosquitoes from Ontario.

The life cycle of an intraerythrocytic hemogregarine, Hepatozoon clamatae, was studied in green frogs (Rana clamitans melanota), bullfrogs (Rana catesbeiana), northern leopard frogs (Rana pipiens), and in the mosquito, Culex territans. Gametogenesis, fertilization, and sporogony occurred within cells of the Malpighian tubules of laboratory-reared Cx. territans that had fed on naturally infected frogs. Mature oocysts containing hundreds of sporocysts were observed in mosquitoes 30 days postfeeding. Each sporocyst enclosed 4 sporozoites. Merozoites appeared in the peripheral circulation of laboratory-reared bullfrogs, green frogs and leopard frogs that had been fed sporocysts 35-70 days previously. Attempts to infect American toads (Bufo americanus) and blue-spotted salamanders (Ambystoma laterale) were not successful. Gamonts of this parasite induced nuclear fragmentation or segmentation in host erythrocytes. The life cycle, morphological, and morphometric features of H. clamatae are compared with H. catesbianae, a similar species that also infects ranids. Nucleotide sequence analysis of the internal transcribed spacer region (ITS-1) of these sympatric species revealed that only 6 nucleotide sites of the 129 base pairs of this region were variable among 4 isolates of H. clamatae and 2 isolates of H. catesbianae. A redescription of H. clamatae is presented based on data from this study and from the original description by Stebbins in 1905.

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PubMed1998

Actinosporean stages of myxozoan parasites of oligochaetes from Lake Sasajewun, Algonquin Park, Ontario: new forms of triactinomyxon and raabeia.

Eight forms of triactinomyxon and 6 forms of raabeia of oligochaetes from Lake Sasajewun, Algonquin Park are described. Of the 8 forms of triactinomyxon, 2 designated as triactinomyxon 'B' and 'E' were found in both Limnodrilus hoffmeisteri and Tubifex tubifex. Three additional forms, designated as triactinomyxon 'A,' 'C,' and 'D,' occurred in L. hoffmeisteri. One form infecting L. hoffmeisteri was identified as Triactinomyxon ignotum Stolc, 1899, and another infecting T. tubifex was tentatively identified as Triactinomyxon dubium Granata, 1924. One form infecting L. hoffmeisteri and Rhyacodrilus coccineus was designated as triactinomyxon 'F.' Of the 6 forms of raabeia, 4 designated as raabeia 'A,' 'B,' 'C,' and 'F' were found in L. hoffmeisteri, and 2 designated as raabeia 'D' and 'E' were recorded in T. tubifex. The sporoplasmic mass of each form of triactinomyxon usually moved posteriorly within the cavity of the spore axis and was released through its posterior end, whereas the sporoplasmic mass of each form of raabeia was released through the anterior end of the epispore. An increase in the number of germ cells was observed in the floating spore stage of triactinomyxon 'B,' 'D,' 'E,' and raabeia 'B.'

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PubMed1998

Actinosporean stages of myxozoan parasites of oligochaetes from Lake Sasajewun, Algonquin Park, Ontario: new forms of echinactinomyxon, neoactinomyxum, aurantiactinomyxon, guyenotia, synactinomyxon and antonactinomyxon.

Six forms (5 of which are new) of echinactinomyxon and 5 new forms of the collective groups neoactinomyxum, aurantiactinomyxon, guyenotia, synactinomyxon, and antonactinomyxon of oligochaetes in Lake Sasajewun, Algonquin Park are described. Five forms of echinactinomyxon designated as echinactinomyxon 'A,' 'B,' 'C,' 'D,' and 'E,' a form of neoactinomyxum, and a form of aurantiactinomyxon were found in Limnodrilus hoffmeisteri. Echinactinomyxon radiatum, a form of synactinomyxon, and a form of antonactinomyxon were recorded from Tubifex tubifex. A form of guyenotia was found in Lumbriculus variegatus. The sporoplasmic mass of these actinosporeans was released through the anterior end of the epispore. An increase in the number of germ cells was observed in the floating spore stage of all forms except echinactinomyxon 'C' and the form of antonactinomyxon.

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PubMed1998

The oligochaetes and their actinosporean parasites in Lake Sasajewun, Algonquin Park, Ontario.

There is little ecological information on actinosporean parasites and their oligochaete hosts. Between 1995 and 1997, about 14,100 oligochaetes belonging to 19 species were collected from Lake Sasajewun. The oligochaete fauna consisted of 5 tubificid, 10 naidid, 3 enchytraeid, and 1 lumbriculid species. The most widely distributed species in the lake were Limnodrilus hoffmeisteri, Dero nivea, and Stylaria lacustris, with L. hoffmeisteri being the most prevalent. The diversity and abundance of worms decreased with increased water depth. Four species, L. hoffmeisteri, Tubifex tubifex, Rhyacodrilus coccineus, and Lumbriculus variegatus, harbored actinosporean parasites and were distributed along shallow areas of the lake shore where the sediment was comprised mainly of clay-mud, with the shoregrass, Littorella americana. The actinosporean parasites of the oligochaetes belong to 25 forms of 8 collective groups. Triactinomyxon 'F' was the most prevalent form, whereas triactinomyxon, raabeia, and echinactinomyxon were the most speciose groups. The overall prevalence of actinosporeans was about 1%. Waterborne spores of different actinosporean forms showed distinct temporal patterns. Spores of triactinomyxon 'F' occurred throughout the sampling season, whereas spores of other forms occurred only at certain times. The presence of waterborne spores peaked from late June to August when water temperatures ranged from 18 to 24 C and coincided with the feeding and growing season of larval fish.

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PubMed1997

The distribution, prevalence, and morphological features of the cystic stage of an apicomplexan parasite of native littleneck clams (Protothaca staminea) in British Columbia.

Sixty-nine of 98 native littleneck clams (Protothaca staminea) collected from Cooper's Cove, Sooke Basin, British Columbia during November 1995 contained apicomplexan cysts. The cysts, which measured 20-150 microns in diameter occurred in several tissues, particularly in the kidney and in connective tissue surrounding the intestine and contained closely packed, banana-shaped zoites that measured about 25 x 4 microns. A pronounced fibrillar layer underlain by labyrinthine structures separated the host tissues from the cyst wall. The apical region of the zoites was reinforced and appeared as an electron-dense, caplike structure. The cysts probably represent a stage of a heteroxenous coccidian life cycle, with a predator of clams serving as the definitive host in which gamogony and sporogony occur.

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PubMed1997

Margolisiella kabatai gen. et sp. n. (Apicomplexa: Eimeriidae), a parasite of native littleneck clams, Protothaca staminea, from British Columbia, Canada, with a taxonomic revision of the coccidian parasites of bivalves (Mollusca: Bivalvia).

Two of 98 native littleneck clams, Protothaca staminea Conrad, from Cooper's Cove, Sooke Basin were infected with an eimeriorin coccidian parasite. Merogonic gamontogonic and sporogonic development were observed in renal tubular epithelial cells. Sporulation of the oocysts occurred within the host. Mature oocysts were spherical mean 41 microns (range 30-44), and contained about 32 subspherical sporocysts (9 x 10 microns), each of which contained 4 sporozoites. Spherical 19 microns (18-20), cyst-like structures and smaller multinucleate bodies, some of which resembled sporocysts, were also seen. A review of the coccidian parasites of bivalves led to the erection of the new genus, Margolisiella (family Eimeriidae Minchin, 1903) to accommodate M. kabatai sp. n., the parasite in Protothaca staminea described herein. Four previously described monoxenous species (Pseudoklossia patellae Debaisieux, P. chitonis Debaisieux, P. tellinovum Buchanan and P. haliotis Friedman, Gardner, Hedrick, Stephenson, Cawthorn et Upton) were also transferred to the new genus. The 2 remaining possibly heteroxenous species (P. pelseneeri Léger and P. glomerata Léger et Duboscq) were retained in the genus Pseudoklossia Léger et Duboscq (family Aggregatidae Labbé, 1899).

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PubMed1996

Analysis of isolates within species of anuran trypanosomes using random amplified polymorphic DNA.

A total of 20 decamer primers were used to generate random applied polymorphic DNA (RAPD) markers from 5 isolates of Trypanosoma fallisi, 3 isolates of T. ranarum, 2 isolates of T. rotatorium, and 2 isolates of T. rotatorium-like trypanosomes in addition to 2 species from the American Type Culture Collection, T. chattoni (ATCC 50294) and Trypanosoma sp. (ATCC 50295). A slight polymorphism was observed among the four isolates of T. fallisi obtained form American toads, Bufo americanus, collected in Algonquin Park, Ontario, Canada, and an isolate obtained from the same species of host collected in Marquette, Michigan, United States, and produced similarity coefficients ranging from 80.7% to 96.9%. Pronounced polymorphism was recorded among the three isolates of T. ranarum from bullfrogs, Rana catesbeiana, collected in Ontario, Canada, and in Maryland, United States, and from a Northern leopard frog, R. pipiens, collected in Minnesota (USA). The similarity coefficients ranged from 54.7% to 59.5%, suggesting that alleles of these isolates were conserved over a wide geographic range. The high degree of polymorphism observed in two isolates of T. rotatorium from a bullfrog collected in Ontario and two isolates of a T. rotatorium-like parasite from the green frog R. clamitans, collected in Louisiana (USA) suggests that they are different species. These results reflect the high similarity among isolates from the same geographic location and the pronounced polymorphism apparent among isolates from distant geographic locations.

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PubMed1996

Comparisons of molecular karyotype and RAPD patterns of anuran trypanosome isolates during long-term in vitro cultivation.

The patterns of random amplified fragments and molecular karyotypes of 12 isolates of anuran trypanosomes continuously cultured in vitro were compared by random amplified polymorphic DNA (RAPD) analysis and pulsed field gradient gel electrophoresis (PFGE). The time interval between preparation of two series of samples was one year. Changes were not observed in the number and size of sharp, amplified fragments of DNA samples from both series examined with the ten primers used. Likewise, changes in the molecular karyotypes were not detected between the two samples of these isolates. These results suggest that the molecular karyotype and the RAPD patterns of the anuran trypanosomes remain stable after being cultured continuously in vitro for one year.

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PubMed1995

Morphological, histochemical, and ultrastructural characterization of the salivary glands and proboscises of three species of glossiphoniid leeches (Hirudinea: Rhynchobdellida).

Morphological and ultrastructural features of the salivary glands and proboscises of Placobdella ornata, Placobdella parasitica, and Desserobdella picta were studied by light and electron microscopy. Chemical composition of the salivary cells was investigated using a variety of histochemical techniques. Placobdella ornata and P. parasitica have compact salivary glands with discrete pairs of anterior and posterior glands, while the salivary cells contain one mucous and three proteinaceous secretions. Salivary glands of D. picta are diffusely arranged and contain two mucous and two proteinaceous secretions. A cobalt-lysine forward-filling technique revealed that individual salivary cells consist of a roughly spherical soma and an elongated ductule. The majority of the internal space in a salivary soma is densely packed with spherical secretory granules which displace the cytoplasm to the periphery of the cell. Bundles of individual ductules enter the base of the proboscis on opposite sides and extend anteriorly. The ductules, also packed with secretory granules, are surrounded by microtubules associated with agranular endoplasmic reticulum, and merge with deep invaginations of the proboscis cuticle. The secretory granules are released at the end of these invaginations or pores. Pores were found on the tip, along the body, and on the luminal wall of the proboscises in all three species.

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PubMed1995

Monoclonal antibodies raised against coccidia and malarial parasites recognize antigenic epitopes found in lankesterellid and adeleorin parasites.

Three murine monoclonal antibodies (MAbs) raised against poultry coccidia or murine malarial parasites were tested for cross-reactivity with 2 sporozoan parasites with different life histories and hosts: Lankesterella minima (Eimeriorina), an intraerythrocytic parasite of frogs that is transmitted by leeches; and Heptazoon catesbianae (Adeleinorina) that infects the red blood cells of frogs and is transmitted by mosquitoes. MAb 1209 recognized both refractile bodies of sporozoites of L. minima, using the indirect fluorescent antibody (IFA) technique and immunoelectron microscopy, and recognized antigens with relative rates of migration (M(r)) of 17, 23, 26, 43, and 48 kDa on a chemiluminescent western blot of L. minima sporozoite antigens. MAbs C(3)4F1 and E12 demonstrated spotty cytoplasmic staining and labeling of the anterior pellicle of L. minima sporozoites, respectively. Gamonts of H. catesbianae labeled with only MAb E12, using IFA. These gamonts exhibited staining similar to that observed with the L. minima sporozoites. The presence of the cross-reactive epitopes recognized by these MAbs in the same conserved locations suggests that these antigens are homologous.

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