[Show abstract][Hide abstract] ABSTRACT: Since the Gordius worm is a parasite of crickets and several arthropods, cases of humans infected with this worm have been rare and accidental. A Gordius worm was obtained from a three-year-old girl who consulted a local clinic in Gwangju, Kyunggi-do, Korea. She lived in a rural area, and had eaten an insect that looked like a cricket. She expelled the worm in vomitus 15 minutes later; in fact, she expelled two worms, but one was discarded. The worm had a grayish white color and an intact outer surface. It was 16 cm in length and 0.6 cm wide. The posterior end of the worm was spirally enrolled and furcated into two caudal lobes, which were nearly cylindrical but showed a somewhat concave medio- ventral surface. The cloacal aperture was round and situated anterior to the point of bifurcation of the lobes. The cloacal aperture was encircled by a dark ring, which was a little removed from the aperture. The crescent fold was reddish brown, and no hairs were noticed over the entire body surface. The worm had the morphological features of a male Gordius. Accidental human cases involving the Gordius worm are rare and this is the first such case in Korea.
Preview · Article · Jul 2003 · Yonsei Medical Journal
[Show abstract][Hide abstract] ABSTRACT: The biology, chromosome number, and karyotype of a lung fluke, Paragonimus westermani (Kerbert, 1878) collected in Haenam, Haenam-gun Chollanam-do, Korea were analyzed. We compared the size of metacercariae from Haenam with those taken from a crayfish collected at Youngam, Youngam-gun, Chollanam-do, Korea. The mean length of P. westermani metacercariae from Haenam was 300.3 microm and that from Youngam was 362.0 microm. Adult worms were recovered from the lungs of experimentally infected dogs. The mean egg sizes obtained from adult flukes were 72.1 x 46.8 microm from Haenam and 93.5 x 54.2 microm from Youngam. Semisulcospira tegulata collected in the Youngam area were found to be infected with cercariae of P. westermani, one of the snail-borne human lung fluke trematodes in Korea. Of 4218 snails studied, 5 (0.12%) harbored P. westrermani larvae. This is the first report of S. tegulata serving as the initial intermediate host of P. westermani. The chromosome numbers of P. westermani from Haenam and Youngam were 2n = 22 and 3n = 33. The diploid type of P. westermani has not been previously reported in Korea.
No preview · Article · Jan 2002 · Experimental Parasitology
[Show abstract][Hide abstract] ABSTRACT: Polyploidy is reported as occurring in Pisidiidae, being found in Pisidium coreanum from Korea. The chromosome number is n = 95 and 2n = 190. Because of the large number of its chromosomes, P. coreanum is obviously a polyploid species. The basic chromosome number for the superfamily Corbiculoidea is X = 18 and X = 19. The polyploid condition found in P. coreanum probably originally resulted from a single event. Once the polyploid condition was reached, the stability of this number has been maintained.
[Show abstract][Hide abstract] ABSTRACT: An antigen-related gene was cloned from a cDNA expression library of Naegleria fowleri by immunoscreening with sera obtained from mice that were either immunized with an amoebic lysate or infected with trophozoites. The coding nucleotide sequence of the cloned gene consisted of 357 bases that were translated into 119 amino acids. This gene was designated as nfa1. The predicted amino acid sequence of Nfa1 protein has two potential glycosylation and three potential phosphorylation sites, and its predicted secondary structure consists of four helices and three corners. The deduced amino acid sequence of Nfa1 protein shares 43% identity with the myohemerythrin (myoHr) protein from a marine annelid, Nereis diversicolor, including 100% identity in conserved regions and iron-binding residues. A phylogenetic tree constructed from amino acid sequences placed the N. fowleri Nfa1 protein outside of a cluster of myoHr proteins from eight invertebrates. A purified recombinant protein that migrated as a 13.1 kDa species in SDS-PAGE was produced. This recombinant protein exhibited a strong immunoreactivity with infected, immune, and anti-Nfal sera. In addition, an anti-Nfa1 serum reacted with an amoeba lysate in immunoblotting analysis. The present nfal gene encoding the myoHr-like protein is the first myoHr gene cloned from protozoa, and the Nfal antigen may be useful in diagnostic studies
No preview · Article · Nov 2001 · Journal of Eukaryotic Microbiology
[Show abstract][Hide abstract] ABSTRACT: To determine whether pathogenic Acanthamoeba culbertsoni trophozoites and lysate can induce cytopathic changes in primary-culture microglial cells, morphological changes were observed by transmission electron microscopy (TEM). In addition, the secretion of two kinds of cytokines, tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1beta), from microglial cells was observed. Trophozoites of pathogenic A. culbertsoni made contact with microglial cells and produced digipodia. TEM revealed that microglial cells cocultured with amoebic trophozoites underwent a necrotic process, accompanied by lysis of the cell membrane. TEM of microglial cells cocultured with amoebic lysate showed that the membranes of the small cytoplasmic vacuoles as well as the cell membrane were lysed. The amounts of TNF-alpha secreted from microglial cells cocultured with A. culbertsoni trophozoites or lysate increased at 6 h of incubation. The amounts of IL-1beta secreted from microglial cells cocultured with A. culbertsoni trophozoites at 6 h of incubation was similar to those secreted from the control group, but the amounts decreased during cultivation with A. culbertsoni lysate. These results suggest that pathogenic A. culbertsoni induces the cytopathic effects in primary-culture rat microglial cells, with the effects characterized by necrosis of microglial cells and changes in levels of secretion of TNF-alpha and IL-1beta from microglial cells.
Preview · Article · Aug 2001 · Clinical and Diagnostic Laboratory Immunology
[Show abstract][Hide abstract] ABSTRACT: In order to observe the cytotoxicity of Acanthamoeba spp., which were isolated from contact lens containers as ethiological agents for the probable amoebic keratitis in Korea, the crystal violet staining method and LDH release assay were carried out. In the crystal violet staining method, among eight contact lens container isolates, isolate 3 (Acanthamoeba KA/LS5) showed 83.6% and 81.8% of cytotoxicity, and isolate 7 (Acanthamoeba KA/LS37) showed 28.2% and 25.1% of cytotoxicity, in 1 mg/ml and 0.5 mg/ml lysate treatments, respectively. Acanthamoeba culbertsoni and A. healyi showed 84.0% and 82.8% of cytotoxicity. Similar results were observed in A. castellanii and A. hatchetti which showed 83.6% and 75.5% of cytotoxicity. Acanthamoeba royreba and A. polyphaga showed 9.0% and 1.7% of cytotoxicity. In the LDH release assay, isolate 3 (20.4%) showed higher cytotoxicity than other isolates in 1 mg/ml lysate treatment. The results provide that at least isolate 3 has the cytotoxic effect against CHO cells and seems to be the pathogenic strain.
Preview · Article · Jul 2000 · The Korean Journal of Parasitology
[Show abstract][Hide abstract] ABSTRACT: Giardia lamblia, a human pathogen causing outbreaks of diarrhea, recently became a focus of great concerns in the fields of both medical and environmental microbiology. To develop the experimental tools to study giardiasis, encystation, one of the major processes in its life cycle, was reconstituted by inducing an axenic culture of a flagellated form of G. lamblia into a cyst form under high concentration of bile and alkaline pH condition. The successful induction was confirmed by Northern analysis of resulting increased expression of the CWP1 gene encoding the cyst wall protein 1. An examination of the encystation process with SEM (scanning electron microscopy) and TEM (transmission electron microscopy) revealed that the trophozoite, a flagellate with a bilateral symmetry, was transformed to a cyst form with an oval-shape and defined filamentous wall. The encystation was found to cause a disappearance of the flagella and an invagination of the adhesive disc. An extensive formation of rER (rough endoplasmic reticulum) was observed after 24 h of induction, indicating an active synthesis and export of proteins during this process. The vital staining of the in vitro- induced cysts showed that most cysts maintained their viability.
No preview · Article · Jun 2000 · Journal of Microbiology and Biotechnology
[Show abstract][Hide abstract] ABSTRACT: To determine whether trophozoites and lysates of pathogenicAcanthamoeba spp. induce apoptosis in primary-culture microglial cells, transmission electron microscopic (TEM) examinations, assessment
of DNA fragmentation by agarose gel electrophoresis, and the TdT-mediated dUTP nick-end labeling assay were performed. When
a trophozoite of pathogenic Acanthamoeba culbertsoni came in contact with a microglial cell, the digipodium was observed by TEM. Nuclear chromatin condensation was observed in
10% of microglial cells, while it was not revealed when they were cocultured with weakly pathogenic Acanthamoeba royreba trophozoites. DNA fragmentation in microglial cells cocultured with the A. culbertsoni lysate was detected by electrophoresis, showing DNA ladder formation, whereas it was hardly observed in microglial cells
cocultured with A. royreba. DNA fragmentation of microglial cells was also confirmed by flow cytometry analysis. The fluorescence of TdT-stained apoptotic
bodies became intensely visible with microglial cells cocultured with the A. culbertsoni lysate. In contrast, with microglial cells cocultured with the A. royreba lysate, only a background level of fluorescence of TdT-stained apoptotic bodies was detected. These results suggest that
some rat microglial cells cocultured with pathogenic A. culbertsoni undergo cytopathic changes which show the characteristics of the apoptotic process, such as nuclear condensation and DNA
Preview · Article · Jun 2000 · Clinical and Diagnostic Laboratory Immunology
[Show abstract][Hide abstract] ABSTRACT: Human pulmonary dirofilariasis has been documented from many parts of the world, but not in Korea so far. We experienced a patient of pulmonary dirofilariasis who had visited a local clinic because of chest pain for 1 month. On chest radiograph, a coin lesion of 2 cm diameter and enlargement of the mediastinal lymph node were shown. An exploratory lung resection was done. Pathologically the lesion was a pulmonary dirofilariasis complicated with necrotic pneumonia, fibrosis, and infarction. At the center of the lesion, degenerated nematode sections with multilayered cuticle, thick musculature, and bilateral internal ridges on each side were found, which was identified to be Dirofilaria immitis. This is the first report of human pulmonary dirofilariasis in Korea.
Full-text · Article · May 2000 · Yonsei Medical Journal
[Show abstract][Hide abstract] ABSTRACT: The chromosome numbers of three species of Korean Corbicula are investigated here: C, fluminea 54, C. papyracea 54, and C. colorata 38. In C. fluminea and C. papyracea, the mitotic chromosomes from 18 sets of three chromosomes each showed that these two species are triploids. In C. colorata, the mitotic chromosomes from 19 groups with two chromosomes each indicated that it is a diploid. C. fluminea and C. papyracea have one set of metacentric chromosomes, five sets of submetacentrics chromosomes, and 12 sets of subtelocentric chromosomes. C. colorata has been considered a subspecies of C. papyracea, but its karyotype indicates that it is a distinct species since it is undoubtedly reproductively isolated from the other two Korean species studied.
No preview · Article · Jan 2000 · Journal of Shellfish Research
[Show abstract][Hide abstract] ABSTRACT: In order to refer to the basic information regarding the identification of isolates obtained from a contact lens container in Korea, the isoelectric focusing gel electrophoresis was employed to compare the isoenzyme band patterns among Acanthamoeba spp. including eight isolates and the simple pairwise dissimilarity analysis was carried out. For an alkaline phosphate development, isolate 7 and Acanthamoeba polyphaga showed homologous band patterns, and isolates 1, 2, and 3 showed the same patterns. For lactate dehydrogenase, similar patterns were observed in isolates 2 and 3. Isolates 3 and 5 showed homologous band patterns for malate dehydrogenase and glucose phosphate isomerase. For hexokinase, isolates 4, 7, and A, hatchetti showed the same band patterns. In others, a considerable number of interstrain polymorphisms was observed in nine isoenzyme band patterns. In Acanthamoeba group II, genetic distances among isolates 1, 2, 3, 4, and 5 ranged from 0.104 to 0.200. In comparison to A. castellanii, A. hatchetti, and A. polyphaga, genetic distances of isolates 7 and 8 were 0.254 and 0.219, respectively. In Acanthamoeba group III, including A. culbertsoni, A. healyi, and A. royreba, isolate 6 had genetic distances which ranged from 0.314 to 0.336. Finally, when comparing to the six reference Acanthamoeba, it was possible to classify isolates 1, 2, 3, 4, and 5, as genetically close-related species and as independent species group. Furthermore, isolates 6, 7 and 8 were identified as independent species as well.
Preview · Article · Jan 2000 · The Korean Journal of Parasitology
[Show abstract][Hide abstract] ABSTRACT: Identification of the genes responsible for the recovery of virulence in brain-passaged Acanthamoeba culbertsoni was attempted via mRNA differential display-polymerase chain reaction (mRNA DD-PCR) analysis. In order to identify the regulatory changes in transcription of the virulence related genes by the brain passages, mRNA DD-PCR was performed which enabled the display of differentially transcribed mRNAs after the brain passages. Through mRNA DD-PCR analysis. 96 brain-passaged amoeba specific amplicons were observed and were screened to identify the amplicons that failed to amplify in the non-brain-passaged amoeba mRNAs. Out of the 96 brain-passaged amoeba specific amplicons, 12 turned out to be amplified only from the brain-passaged amoeba mRNAs by DNA slot blot hybridization. The clone, A289C, amplified with an arbitrary primer of UBC #289 and the oligo dT11-C primer, revealed the highest homology (49.8%) to the amino acid sequences of UPD-galactose lipid transferase of Erwinia amylovora, which is known to act as an important virulence factor. The deduced amino acid sequences of an insert DNA in clone A289C were also revealed to be similar to cpsD, which is the essential gene for the expression of type III capsule in group B streptococcus. Upregulated expression of clone A289C was verified by RNA slot blot hybridization. Similar hydrophobicity values were also observed between A289C (at residues 47-66) and the AmsG gene of E. amylovora (at residues 286-305: transmembrane domains). This result suggested that the insert of clone A289C might play the same function as galactosyl transferase controlled by the AmsG gene in E. amylovora.
Preview · Article · Jan 2000 · The Korean Journal of Parasitology
[Show abstract][Hide abstract] ABSTRACT: To determine the pathogenicity of Acanthamoeba spp. isolated in Korea and to develop a isoenzymatic maker, the mortality rate of infected mice, in vitro cytotoxicity against target cells and isoenzyme band patterns were observed. Five isolates of Acanthamoeba spp. (YM-2, YM-3, YM-4, YM-5, and YM-7) were used in this study as well as three reference Acanthamoeba spp. (A. culbertsoni, A. hatchetti, and A. royreba). According to the mortality rate of infected mice, Korean isolates could be categorized into three groups high virulent (YM-4), low virulent (YM-2, YM-5, YM-7) and the nonpathogenic group (YM-3). In addition, the virulence of Acanthamoeba spp. was enhanced by brain passage in mice. In the cytotoxicity assay against chinese hamster ovary cells, especially, the cytotoxicity of brain-passaged amoebae was relatively higher than the long-term cultivated ones. The zymodeme patterns of glucose-6-phosphate dehydrogenase (G6PD), malate dehydrogenase (MDH), hexokinase (HK), glutamate oxaloacetate transaminase (GOT) and malic enzyme (ME) of Acanthamoeba spp. were different among each isolate, and also between long-term cultured amoebae and brain passaged ones. In spite of the polymorphic zymodemes, a slow band of G6PD and HK, and an intermediate band of MDH were only observed in pathogenic Acanthamoeba spp., which should be used as isoenzymatic makers.
Preview · Article · Jul 1999 · The Korean Journal of Parasitology
[Show abstract][Hide abstract] ABSTRACT: The first case was 7-month-old immunodeficiency girl in whom the diagnosis of Acanthamoeba pneumonia was established by culture of a bronchial washing. The patient had been ill for a month when she was admitted due to neonatal thrombocytopenia with respiratory difficulty and treated with gammaglobulin and steroid. Her chest X-ray showed diffuse alveolar consolidation on the left lung with interstitial hazziness and a partial sign of hyperinflation on the right lung. Laboratory tests showed that the Candida antigen was negative and Pneumocystis carinii was not detected. Mycoplasma antigen was negative. All the immunoglobulin levels (IgG, IgA, IgM) were below the normal range. Five days later the patient expired. The second case was an immunosuppressed 7-year-old boy in whom Acanthamoeba trophozoites were found in the skin biopsy, followed by meningitis leading to death. About five days after a laceration on the region of the left eyebrow, a painful bean-sized nodule developed at the suture site and it was treated with antibiotics and corticosteroid. The skin biopsy showed severe inflammatory cell infiltration. Trophozoites were scattered near the blood vessels throughout the inflammatory zone. From one weak prior to admission, the patient had suffered from vomiting, indigestion and mild fever. Skin nodules with tenderness appeared all over his body surface. Examination of cerebrospinal fluid showed clear, Gram stain was negative, bacterial culture negative, India ink preparation negative, and organism on wet smear negative. On admission day 10, focal seizure of the left extremity occurred. Brain CT revealed calcific density on the left parietal lobe area and hypodensity on the left basal ganglia. He became comatous and died immediately after discharge. Until now in Korea, two cases that are described in this paper, one Acanthamoeba meningoencephalitis case and seven Acanthamoeba keratitis cases including two unreported keratitis cases that are reported in this paper have been presented.
Preview · Article · Nov 1998 · Yonsei Medical Journal
[Show abstract][Hide abstract] ABSTRACT: The prevalence of Loa loa infections in non-endemic areas such as Korea is very low, even though it is quite common in the endemic regions of West and Central Africa. We describe a patient who presented with temporary localized edema (classical Calabar swellings) after travelling to Cameroon and in whom the diagnosis of loiasis was made by ELISA. This is the second reported case of loiasis in Korea. As international travel is becoming more frequent, Loa loa infection should be considered in the differential diagnosis for patients with eosinophilia and Calabar swellings in Korea.
Preview · Article · May 1998 · Yonsei Medical Journal
[Show abstract][Hide abstract] ABSTRACT: The differential display reverse transcription polymerase chain reaction (DDRT-PCR) analysis was performed to identify the pathogenic strain specific amplicons. mRNAs were purified from the trophozoites of the pathogenic strain YS-27 and the non-pathogenic strain S 16, respectively. Three kinds of first stranded cDNAs were reverse transcribed from the mRNAs by one base anchored oligo-dT11M (M: A, C, or G) primers. Each cDNA template was used for DDRT-PCR analysis. A total of 144 pathogenic strain specific amplicons was observed in DDRT-PCR analysis using primer combinations of the 11 arbitrary primers and the 3 one base anchored oligo-dT11M primers. Of these, 31 amplicons were verified as the amplicons amplified only from the mRNAs of the pathogenic strain by DNA slot blot hybridization. Further characterization of the 31 pathogenic strain specific amplicons by DNA slot blot hybridization analysis using biotin labeled probes of the PCR amplified DNA of cysteine proteinase genes revealed that 21 of them were amplified from the mRNAs of the cysteine proteinase genes. Four randomly selected amplicons out of the rest 10 amplicons were used for screening of cDNA library followed by immunoscreening and all of them were turned out to be amplified from the mRNA.
Preview · Article · Oct 1997 · The Korean Journal of Parasitology
[Show abstract][Hide abstract] ABSTRACT: Acanthamoeba sp. YM-4 is similar to A. culbertsoni based upon morphological characteristics of trophozoites and cysts. However, based on other characteristics, pathogenicity to mice, in vitro cytotoxicity and isoenzyme patterns. Acanthamoeba sp. YM-4 was quite different from A. culbertsoni. Restriction fragment length polymorphism (RFLP) analysis of mtDNA is useful in the classification of members belonging to the genus Acanthamoeba. Therefore, in this study, RFLP analysis of Acanthamoeba mtDNAs was accomplished using five restriction enzymes: HaeIII, HindIII, ClaI, PvuII and SalI. Each restriction enzyme produced approximately 3-15 fragments (range: from 0.6 kbp to 34.4 kbp). The mtDNA genome size, calculated by the summation of restriction fragments, averaged 46.4 kbp in Acanthamoeba sp. YM-4, 48.3 kbp in A. culbertsoni and 48.8 kbp in A. polyphaga, respectively. Digested mtDNA fragments of Acanthamoeba sp. YM-4 contained nine and seven same size fragments, respectively, from a total of 67 and 69 fragments observed in A. culbertsoni and A. polyphaga. An estimate of the genetic divergence was 10.1% between Acanthamoeba sp. YM-4 and A. culbertsoni, and 9.9% between Acanthamoeba sp. YM-4 and A. polyphaga.
Preview · Article · Jul 1997 · The Korean Journal of Parasitology
[Show abstract][Hide abstract] ABSTRACT: In the present communication, YS-27, a Korean strain of Entamoeba histolytica is described for the isolation and establishment of axenic cultivation. E. histolytica, designated as strain "YS-27", was isolated from the pus of a hepatic abscess obtained from a 72 year old inpatient of August 10, 1969. Specimens, were obtained by needle aspiration, inoculated immediately and weekly cultured in a modified diphasic medium at 37 degrees C. Strain YS-27 had been maintained for more than 15 years by weekly subculture until February, 1985. These cultures were transferred to a monoxenic TTY-SB medium seeded with a trypanosomatid of the genus Crithidia. Penicillin G, 2 to 10 x 10(3) International units and Streptomycin, 2 to 10 mg per 100 ml, were added to the cultures to eliminate the bacteria. After more than one year later, these two organisms were well maintained by transfer every 3 or 4 days until January, 1986 at 37 degrees C in TTY-SB medium in the absence of other microorganisms. These monoxenic cultures were then transferred to TYI-S-33 medium. Strain YS-27 alone had not been growing at the time of transfer, but when overlaid with Crithidia at intervals of 3 to 4 days, strain YS-27 propagated well. The Crithidia died out several weeks later after several passages. Beginning in April, 1986, strain YS-27, was successfully established in axenic culture in TYI-S-33 medium and has been maintained in continuous culture and multiplied well to present.
Preview · Article · Jan 1996 · The Korean Journal of Parasitology