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1
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Redefining parasite life cycles through epidemiology, pathology and developmental biology

100%
Conn D. B.
Annals of Parasitology
|
2016
|
tom 62
|
nr Suppl.
2
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Recent advances in the reproductive and developmental biology of Cestoda and Trematoda

100%
Conn D. B.
Wiadomości Parazytologiczne. Suplement
|
2007
|
tom 53
3

Ultrastructure of the embryonic envelopes and associated maternal structures of Distoichometra bufonis [Platyhelminthes, Cestoidea, Nematotaeniidae]

100%
Conn D. B.
Acta Parasitologica
|
1999
|
tom 44
|
nr 1
Eggs within paruterine capsules of gravid proglottids of Distoichometra bufonis were examined by light and transmission electron microscopy. The embryonic capsule was membranous, but was immediately underlain by a non-uniform subcapsular lamina that was an intracellular component of the outer embryonic envelope. The subcapsular lamina was thick and semi-rigid on anterior and posterior poles, but thin and membranous laterally, giving the entire egg a laterally oblong shape. In contrast, the embryophore was spherical and uniform in thickness. The paruterine capsule walls were derived from layers of flattened processes of medullary parenchyma cells lined internally with a layer of uterine epithelium. All these layers extended inward to form parenchyma-uterine partitions segregating each egg into an individual chamber. The uterine epithelium was very thin, syncytial, and contained numerous vesicles. Little uterine secretory product occurred in the uterine lumen or on the outer surface of the embryonic capsule. Except for the unique subcapsular lamina, most features of the eggs and paruterine capsule resembled those of other nematotaeniid species. The paruterine capsule wall was similar to that of Mesocestoides lineatus, a species whose paruterine organ lacks parenchyma-uterine partitions.
4
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Functional morphology and ultrastructure of the eggs, uterus and paruterine capsules of Distoichometra bufonis [Platyhelminthes: Cestoidea: Nematotaeniidae]

100%
Conn D. B.
Wiadomości Parazytologiczne
|
1998
|
tom 44
|
nr 3
5
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The differentiation and functional ultrastructure of the parenchymatic egg envelopes: their role in cestode embryogenesis

63%
Swiderski Z., Conn D. B.
Wiadomości Parazytologiczne. Suplement
|
2004
|
tom 50
6
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Fertilization in the parasitic Platyhelminthes

63%
Conn D. B., Swiderski Z.
Wiadomości Parazytologiczne. Suplement
|
2004
|
tom 50
7

Ultrastructural aspects of fertilization in Proteocephalus longicollis, Inermicapsifer madagascariensis, and Mesocestoides lineatus [Platyhelminthes, Cestoda]

63%
Swiderski Z., Conn D. B.
Acta Parasitologica
|
1999
|
tom 44
|
nr 1
Ultrastructural aspects of fertilization were studied in three cestode species: one proteocephalid with biflagellate spermatozoa, Proteocephalus longicollis, and two cyclophyllideans with uniflagellate spermatozoa, Inermicapsifer madagascariensis (Anoplocephalidae) and Mesocestoides lineatus (Mesocestoididae). Fertilization in all three species occurs in the oviduct lumen or in the fertilization canal proximal to the ootype, where the formation of the embryonic capsule precludes sperm contact with the oocyte. Cortical granules are not present in the oocytes of any of the three species. Spermatozoa coil spirally around the oocytes and syngamy occurs by lateral fusion of oocyte and sperm plasma membranes. In the ootype one (Proteocephalus and Inermicapsifer) or two (Mesocestoides) vitellocytes associate with the fertilized oocyte, forming a membranous capsule which encloses both cell types. In this stage, spirally coiled sperm flagella adhere partly to the external oocyte surfaces, and partially penetrate into the perinuclear cytoplasm. Usually, several loops of the spermatozoon occur within the oocyte cytoplasm. The electron-dense sperm nucleus within the oocyte cytoplasm becomes progressively electron lucent after penetration. Simultaneously with chromatin decondensation, the elongate sperm nucleus changes shape, forming a spherical male pronucleus, which attains the size of the female pronucleus. Cleavage begins immediately after pronuclear fusion.
8
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Content available

Comparative ultrastructure of fertilization in parasitic platyhelminthes

63%
Swiderski Z., Conn D. B.
Wiadomości Parazytologiczne
|
1998
|
tom 44
|
nr 3
9

Ultrastructure of digenean trematode eggs (Platyhelminthes: Neoophora): A review emphasizing new comparative data on four European Microphalloidea

51%
Conn D. B., Swiderski Z., Miquel J.
Acta Parasitologica
|
2018
|
tom 63
|
nr 1
10

Ultrastructure of the oncospheral envelopes in the pseudophyllidean cestode Eubothrium salvelini [Schrank, 1790]

51%
Swiderski Z., Brunanska M., Mlocicki D., Conn D. B.
Acta Parasitologica
|
2005
|
tom 50
|
nr 4
The aim of this study is to describe the ultrastructure of oncospheral envelopes in the pseudophyllidean cestode Eubothrium salvelini, a parasite of salmonid fishes. Our results indicate that the eggs of E. salvelini differ in their ultrastructure from those of the majority of the Pseudophyllidea. The entire embryonic development, including differentiation of the mature, infective oncosphere of E. salvelini takes place in the uterus and not in the aquatic environment, as is common for other pseudophyllideans. Egg maturation is not simultaneous; together with mature eggs containing fully differentiated oncospheres, can be found numerous small immature, nonfertilized and nonviable abortive eggs. The normally developing eggs of E. salvelini are large, oval and nonoperculated. Three envelopes surround the infective hexacanths: (1) the eggshell; (2) the outer envelope originating from macromere fusion; (3) the inner envelope formed by numerous mesomeres which usually persist in the mature eggs. Our observations confirm that both the outer and the inner envelopes of E. salvelini eggs are cellular in origin and syncytial in nature. The typical oncospheral membrane was not observed in this species. New data on the origin and ultrastructure of oncospheral envelopes may present useful criteria for phylogenetic analysis of lower cestodes. Ontogenetic characters, such as ultrastructural aspect of morphogenesis of infective larval stages, are proposed as phylogenetic indicators in studies of cestode evolution.
11

Scanning electron microscopy of the scolex and neck of the tapeworm Cathetocephalus thatcheri [Cestoda, Tetraphyllidea] from the sandbar shark Carcharhinus plumbeus [Chondrichthyes, Elasmobranchii]

51%
Conn D. B., Whittaker F. H., Curless W. W.
Acta Parasitologica
|
2004
|
tom 49
|
nr 1
Scanning electron microscopy of the scolex and neck of the cestode Cathetocephalus thatcheri confirmed earlier light-microscope descriptions showing that the scolex consists of a single apical lenticular adhesive complex, oriented transverse to the long axis of the strobila. The apical region of the scolex consists of a medial ridge from which extend numerous pairs of short bilamellate septa. On each side of the medial ridge, along its entire length, is a ridge in the form of sinusoidal wave that forms a loop around each of the septa. The tegument of the anterior surface of the medial ridge is formed into numerous tegumental folds that are aligned perpendicular to the long axis of the ridge. Posteriorly, the scolex has a rugose surface and forms a collar or lip around the upper part of the adherent surface. The sinusoidal ridges are continuous around the ends of the scolex. At the ends, the medial ridge tapers considerably. The tegument of the neck bears numerous papillae. No microtriches were observed on any part of the scolex or neck.
12

A new type of endogenous asexual proliferation in cyclophyllidean metacestodes

51%
Galan-Puchades M. T., Fuentes M. V., Conn D. B.
Acta Parasitologica
|
2002
|
tom 47
|
nr 4
We describe 4 metacestodes classified according to their morphology as belonging to the genus Mesocestoides. (Cestoda, Cyclophyllidea) in the abdominal cavity of an individual wood mouse, Apodemus sylvaticus (Rodentia, Muridae) trapped in a Spanish Mediterranean ecosystem. The morphological study of the metacestodes shows evidence of three types of asexual proliferation: longitudinal fission (presence of supernumerary suckers in the scolex); budding; and a third form of asexual division not previously described in cestodes, with a mother tetrathyridium containing some daughter metacestodes (endopolygeny). For the first time we have demonstrated different mechanisms of asexual division in a tetrathyridium-type metacestode, apparently of the genus Mesocestoides. Furthermore, this is the first report of endogenous asexual proliferation in any metacestode exhibiting primitive or gymnosomic development.
13

Fertilization in the cestode Gallegoides arfaai [Mobedi et Ghadirian, 1977] Tenora et Mas-Coma, 1978 [Cyclophyllidea, Anoplocephalidae]

51%
Swiderski Z., Conn D. B., Miquel J., Mlocicki D.
Acta Parasitologica
|
2004
|
tom 49
|
nr 2
Fertilization in the anoplocephalid cestode Gallegoides arfaai with uniflagellate spermatozoa was examined by means of light and transmission electron microscopy. Fertilization in this species occurs in the oviduct lumen or in the fertilization canal proximal to the ootype, where the formation of the embryonic capsule precludes sperm contact with the oocyte. Cortical granules are not present in the cytoplasm of oocytes of this species. However, two other types of large bodies containing granular material, one of homogeneous moderate electron density and one of heterogeneous moderate electron density, are present in the perinuclear cytoplasm of the oocytes. Spermatozoa coil spirally around the oocytes and syngamy occurs by lateral fusion of oocyte and sperm plasma membranes. In the ootype, one vitellocyte associates with the fertilized oocyte, forming a membranous capsule which encloses both cell types. In this stage, spirally coiled sperm flagella adhere partly to the external oocyte surfaces, and partially enter into the perinuclear cytoplasm. Usually, several loops of the spermatozoon occur within the oocyte cytoplasm. The electron-dense sperm nucleus becomes progressively electron-lucent within the oocyte cytoplasm after entry. Simultaneously with chromatin decondensation, the elongate sperm nucleus changes shape, forming a spherical male pronucleus, which attains the size of the female pronucleus. Cleavage begins immediately after pronuclear fusion.
14
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Content available

Effect of povidone iodine, chlorhexidine digluconate and toyocamycin on amphizoic amoebic strains, infectious agents of Acanthamoeba keratitis – a growing threat to human health worldwide

45%
Padzik M., Baltaza W., Conn D. B., Szaflik J. P., Chomicz L.
Annals of Agricultural and Environmental Medicine
|
2018
|
tom 25
|
nr 4
15
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Content available

Examination of oral biofilm microbiota in patients using fixed orthodontic appliances in order to prevent risk factors for health complications

45%
Perkowski K., Balraza W., Conn D. B., Marczynska-Stolarek M., Chomicz L.
Annals of Agricultural and Environmental Medicine
|
2019
|
tom 26
|
nr 2
16

Electron microscope study on oncospheral envelope morphogenesis in the dilepidid cestode, Dilepis undula [Schrank, 1788]

45%
Swiderski Z., Salamatin R. V., Grytner-Ziecina B., Kornyushin V. V., Conn D. B.
Acta Parasitologica
|
2004
|
tom 49
|
nr 4
The origin, differentiation and ultrastructural characteristics of oncospheral envelopes surrounding invasive oncospheres of the dilepidid cestode Dilepis undula are described. In the early preoncospheral phase three primary embryonic envelopes are formed: (1) the capsule; (2) the outer envelope formed by two macromeres; and (3) the inner envelope originating from fusion of two or three mesomeres. Both the outer and inner envelopes of D. undula are therefore cellular in origin and syncytial in nature. Mature eggs of D. undula are slightly oval, measuring 40-50 x 56 µm in diameter. Within fully formed eggs, the mature, invasive oncospheres, 36-40 µm in diameter, are surrounded by five oncospheral or egg envelopes: (1) outer shell; (2) outer envelope; (3) inner envelope; (4) oncospheral membrane; and (5) hook region membrane covering only one pole of the hexacanth. The ultrastructural characteristics of D. undula oncospheral envelopes are discussed in comparison with those of previously examined dilepidids and other cyclophyllideans.
17

Mass spectrometry analysis of the excretory-secretory (E-S) products of the model cestode Hymenolepis diminuta reveals their immunogenic properties and the presence of new E-S proteins in cestodes

39%
Bien J., Salamatin R., Sulima A., Savijoki K., Conn D. B., Nareaho A., Mlocicki D.
Acta Parasitologica
|
2016
|
tom 61
|
nr 2
18

Ultrastructure of oncospheral hook formation in the cestode Mosgovoyia ctenoides [Railliet, 1890] Beveridge, 1978 [Cyclophyllidea, Anoplocephalidae]

39%
Mlocicki D., Swiderski Z., Conn D. B., Eira C., Miquel J., Baranowska-Korczyc A.
Acta Parasitologica
|
2005
|
tom 50
|
nr 2
The ultrastructure of oncospheral hook formation in the anoplocephalid cestode Mosgovoyia ctenoides (Railliet, 1890) Beveridge, 1978, is described. The hook morphogenesis takes place inside the six symmetrically arranged hook-forming cells, the oncoblasts. They show characteristic large nuclei of semilunar shape, localized at one pole of the embryo. At the beginning of the hook formation, the "hook-forming centre" appears in the cytoplasmic part of each oncoblast. It consists of numerous free ribosomes and polyribosomes surrounded by several mitochondria and Golgi complexes. The hook-forming centre is involved in synthesis of an electron-dense, undifferentiated hook primordium, which undergoes progressive differentiation and elongation into the fully developed hook. A fully formed oncospheral hook consists of the three parts: blade, shank, and base. Each hook, at the site of its protrusion from the oncosphere, is surrounded by two electron-dense rings interconnected by a circular septate junction. The hook material consists of two or three layers that differ in electron density: (1) a moderately electron-dense core, (2) a middle layer of low electron density, and (3) a highly osmiophilic cortex. Wide bands of hook muscles are attached to the basal and collar parts of the hook. The hook blades project outside of the oncospheral body into a large cavity delimited by the hook region membrane attached at this pole directly to the oncospheral surface. In the fully developed oncosphere of M. ctenoides, the three pairs of oncospheral hooks and their muscles form a complex "hook muscle system", responsible for coordinated hook action. The differentiation and ultrastructure of oncospheral hooks in the oncospheres of M. ctenoides are compared to those described in other cestode species.
19

Differentiation and ultrastructure of the oncospheral envelopes of the cestode Joyeuxiella echinorhyncoides [Sonsino, 1889] [Cyclophyllidea, Dipylidiidae]

39%
Swiderski Z., Miquel J., Agostini S., Conn D. B., Chomicz L., Grytner-Ziecina B.
Acta Parasitologica
|
2004
|
tom 49
|
nr 3
In the preoncospheral stage of development of Joyeuxiella echinorhyncoides three primary embryonic envelopes are formed: (1) the capsule; (2) the outer envelope formed by two macromeres, and (3) the inner envelope originating from fusion of three mesomeres. Both the outer and inner envelopes of J. echinorhyncoides are therefore cellular in origin and syncytial in nature. Mature eggs of J. echinorhyncoides are spherical, measuring 47-60 x 38-48 µm in diameter. Each uterine capsule contains one egg. Within fully formed eggs, the mature oncospheres, 25-27 µm in diameter, are surrounded by five oncospheral or egg envelopes: (1) the outer shell, which originates from the initially delicate membranous capsule that becomes encrusted by the uterine-derived shell material that is deposited on it; (2) the outer envelope, still containing two large macromere nuclei; (3) the inner envelope, with three characteristic nuclei of mesomeres, and which secretes the electron-dense protective embryophore layer at its outer surface; (4) a unique type of “oncospheral membrane” that never becomes delaminated or detached from the rest of the inner envelope as a separate layer; and (5) a surface filament layer, composed of numerous elongated processes separated by cisternae containing material of very high electron density. The so-called “hook region membrane” covers only one pole of the mature oncosphere and is directly attached to the oncosphere surface. The ultrastructure of the oncospheral envelopes in J. echinorhyncoides shows some similarity to that described in the only other species of dipylidiid cestode examined to date, the cosmopolitan type-species, Dipylidium caninum. Differences between these two species include the absence of “hook region membrane”, as well as bilayered and striated embryophore unique to D. caninum, and the undetached “oncospheral membrane” and unique “surface filament layer” and “interdigitating cisternae”, characteristic of J. echinorhyncoides eggs.
20

Human dirofilariasis due to Dirofilaria repens in Ukraine, an emergent zoonosis: epidemiological report of 1465 cases

27%
Salamatin R. V., Pavlikovska T. M., Sagach O. S., Nikolayenko S. M., Kornyushin V. V., Kharchenko V. O., Masny A., Cielecka D., Konieczna-Salamatin J., Conn D. B., Golab E.
Acta Parasitologica
|
2013
|
tom 58
|
nr 4
The filarial nematode Dirofilaria repens is currently considered to be one of the most extensively spreading human and animal parasites in Europe. In Ukraine, reporting cases of dirofilariasis has been mandatory since 1975, and the disease was included in the national surveillance system for notifiable diseases. Up until December 31st 2012, a total of 1533 cases have been registered, with 1465 cases occurring within the previous 16 years. Most of the cases of dirofilariasis were registered in 6 regions: Kyiv, and the Donetsk, Zaporizhzhya, Dnipropetrovsk, Kherson and Chernihiv oblasts. In the years 1997–2002 the highest incidence rate was noted in the Kherson oblast in the south of the country (9.79 per 100 000 people), and the lowest in western Ukraine (0.07–1.68 per 100 000 people). D. repens infections were registered in all oblasts. Parasitic lesions were most often located in the head, the subconjunctival tissue and around the eyes. D. repens lesions were also found in the limbs, torso, male sexual organs, and female mammary glands. Dirofilariasis was diagnosed in persons aged from 11 months to 90 years old, most often among people between 21–40 years of age. Most patients had only one parasitic skin lesion; the majority of isolated nematodes were female. The results of our analysis point to a constant increase in D. repens dirofilariasis incidence in humans in Ukraine. Despite educational efforts, infections have become more frequent and the territory in which the disease occurs has enlarged to encompass the whole of Ukraine. Nevertheless, the Ukrainian sanitary-epidemiological services managed to achieve some measure of success, e.g. by creating a registration system for D. repens infections and establishing proper diagnostics for the disease.
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