Electron microscopy of the separated outer tegument of the sparganum and its antigenicity.

The author reported previously on separation of the outer tegument of the spargana (plerocercoids of Spirometra mansoni) using high concentration of urea solution. To determine which layer of the tegument is separated by this method, an electron microscopic analysis has been processed in this study. It was confirmed that the basement layer of the tegument is separated from the parenchyme of the sparganum. In addition, the antigenicity of the separated outer tegument against the human sparganosis patient sera was evaluated. Numerous antigenic proteins, including 16 and 55 kDa proteins, were noticed in the separated tegument; however, there were no diagnostic 31/36 kDa molecules in this tegument. The molecules reactive with the patient sera in the tegument are to be characterized in future studies.

[Scanning electron microscope observation of plerocercoid from Rana nigromaculata in Guizhou Province].

Five integral and active plerocercoids collected from naturally infected frogs were fixed by glutaraldehyde-osmic acid, dehydrated in graded series of ethanol, dried via vacuum freeze and coated with carbon gold. They were then observed by scanning electron microscopy. The results showed that the anterior and posterior ends of the plerocercoids were slightly swell and without segmentation. Annular furrows ran irregularly along the body surface. The anterior end was drawn inside and had a deep dorsoventral hollow, around which, the plasma membrane displayed a lip bulge. The posterior end was similar to the anterior one in the shape, but a fissure in its central part was comparatively narrower and shallower than the hollow in the anterior end. There were thousands of pits and grooves on the body surface, unequal in size. The whole body surface of the plerocercoid was densely covered by sharp spine-like microtriches.

Molecular identification of a causative parasite species using formalin-fixed paraffin embedded (FFPE) tissues of a complicated human pulmonary sparganosis case without decisive clinical diagnosis.

PCR-based molecular diagnosis was made for the identification of causative agents of the clinically suspected pulmonary proliferative sparganosis case found in Thailand using formalin-fixed paraffin-embedded (FFPE) biopsy specimens. As a reference, FFPE biopsy specimen from a typical cutaneous sparganosis case was examined together. DNA samples were extracted from tissues and two partial fragments of cytochrome c oxidase subunit 1 (cox1) gene were amplified for the detection of Spirometra DNA. Two cox1 fragments were amplified successfully for both specimens. After alignment of nucleotide sequences of the PCR-amplicons, the causative agents of both cases were identified as Spirometra erinaceieuropaei.

Identification and characterization of a mitochondrial manganese superoxide dismutase of Spirometra erinacei.

A gene encoding the manganese superoxide dismutase (Mn-SOD) of Spirometra erinacei was identified, and the biochemical properties of the recombinant enzyme were partially characterized. The S. erinacei Mn-SOD gene consisted of 669 bp, which encoded 222 amino acids. A sequence analysis of the gene showed that it had typical molecular structures, including characteristic metal-binding residues and motifs that were conserved in Mn-SODs. An analysis of the N-terminal presequence of S. erinacei Mn-SOD revealed that it had physiochemical characteristics commonly found in mitochondria-targeting sequences and predicted that the enzyme is located in the mitochondria. A biochemical analysis also revealed that the enzyme is a typical Mn-SOD. The enzyme was consistently expressed in both S. erinacei plerocercoid larvae and adult worms. Our results collectively suggested that S. erinacei Mn-SOD is a typical mitochondrial Mn-SOD and may play an important role in parasite physiology, detoxifying excess superoxide radicals generated in the mitochondria.

Ultrastructure of the scolex, rhyncheal system and bothridial pits of Otobothrium mugilis (Cestoda: Trypanorhyncha).

The ultrastructure of the scolex tegument, bothridial pits (=ciliated pits) and rhyncheal system of Otobothrium mugilis Hiscock, 1954 is described from plerocerci collected from the teleosts Arius graeffei Kner et Steindachner and Mugil cephalus Linnaeus. Scanning electron microscopy revealed that filamentous microtriches with shortened caps are abundant across the entire surface of the tegument. Palmate microtriches are dominant on the bothridia and their margins. The surfaces of bothridial pits were covered with large bifid microtriches. The bothridial pits are strongly muscularised invaginations of the tegument. Nervous tissues were not observed within the pits and it is probable that these structures function as accessory attachment structures. The wall of each tentacle sheath consists of one to three bands of fibrils, lined internally by a thin cytoplasmic layer. The tentacular walls are cellular, containing myofilaments. The fibrils of the tentacular walls are arranged into discrete blocks of parallel fibrils and appear to be intracellular. Tentacular walls are lined externally by a modified membrane with an external glycocalyx. Tentacular hooks are solid, bound externally by a membrane. The body of the hook contains numerous longitudinal canaliculi and an electron-opaque medulla lies at the centre of the hook.

Sparganum proliferum: an overview of its structure and ultrastructure.

A detailed study of the structure and ultrastructure of Sparganum proliferum was made possible for the first time thanks to the successful in vitro and in vivo maintenance of this rare parasite. Although S. proliferum exhibits many of the classical tegumental and parenchymal structures previously described for other larval cestodes, these are either arranged in a distinct fashion or, in some cases, may be completely different. Among the latter and of special interest are the single or multiple parenchymal cavities, surrounded by tegument, which in some instances appear to act as a primitive digestive tract.

Proliferative sparganosis in a cat.

Aberrant, proliferative sparganosis was diagnosed in a 6-yr-old male domestic long-haired cat from Gainesville, Florida. The cat spent all of its life in Florida. Postmortem examination revealed lesions and spargana in the stomach, spleen, and liver. By light and electron microscopy, unusual mononuclear cells, interpreted as host-derived monocytes, were evident in the stroma of the spargana. Retrovirus-like particles were present in the cytoplasm of some of these cells.

Disseminated parasitosis in an immunosuppressed patient. Possibly a mutated sparganum.

The autopsy of a man who died of Hodgkin disease revealed that a peculiar metazoan parasite had proliferated and disseminated throughout his body. The parasite could not be identified; however, electron microscopical studies revealed that it had the structure of a flatworm. This, together with its shape and structure, convinced us that the parasite was an aberrant sparganum manifesting uncontrolled proliferation and dissemination.