• Parasites, Hosts and Diseases
• /
• v.22 no.2
• /
• pp.259-266
• /
• 1984

Present study was undertaken to elucidate the changes of the ultrastructure of Naegleria fowleri trophozoite in brain tissue of mice and culture medium. Naegleria fowleri, 0359 strain, which used in this study was cultured in axonic liquid medium, CGVS medium. Each mouse was inoculated with amoebas intranasally under secobarbital anesthesia, and sacrificed on 7th day after the infection. Comparative observation of the ultrastructure of the amoebas in axonic culture and experimentally infected mice brain was done with transmission electron microscope. The results are summarized as follows: 1. The amoebas in mouse brain tissue were round in outline, whereas those of amoebas from axonic culture showed irregular appearance. 2. Mitochondria in the amoebas from axonic culture was oval, round and cylindrical shape and darkly stained, whereas those of the amoebas from mouse brain tissue showed dumbbell shape together with above forms. The stain was not unique, but light and/or dark. 3. Rough endoplasmic reticulum of amoebas in brain tissue was tubular, but from culture it was vesicular or tubular in shape. 4. Emity vacuoles were demonstrated in amoebas from culture, while food vacuoles with myelinated structures were abundant in those from tissue, suggesting a strong phagocytic activity. 5. Mouse brain tissue in ected were extensively destroyed, and Polymorphonuclear leukocytes were infiltrated predominantly with inflammatory lesion. Amoebas were observed in the vicinity of the capillary.

• Parasites, Hosts and Diseases
• /
• v.22 no.2
• /
• pp.153-160
• /
• 1984

An experimental study was undertaken to observe the difference in susceptibility of mouse strains to Metagonimus yokogawai infection by estimating it from worm recovery rate and dimension of worms. It was also studied the effects of prednisolone injection on the chronological pattern of worm recovery in ICR mice. The metacercariae were obtained from sweetfish and 300 in each number were given to 5 strains (CBH, A, DBA, $C^{57}BL$ and KK) of mice, and after 7 days period, the worms were collected from their intestine. Prednisolone at the dose of 10 mg/kg was injected to ICR mice every other day from 7 days prior to infection until sacrificed at 6 hours to 35th post-infection day. ICR mice infected with M. yokogawai but untreated were used for controls. The success rate in infection of mice ranged 25.0-83. 3% by strains, the worm recovery rate 1. 2-18. 9%, and the average size of worms O. 554-0. 683 mm long and 0.214-0.244 mm wide. The higher rates and larger size of worms were observed in KK and $C^{57}BL$ strains than others and the difference was statistically significant. In ICR mice for control, the worm recovery rate until 1 day after infection was relatively high (38-66%) but it became much lower (less than 0.7%) during 1-35 days. However, prednisolone injection brought about persistently high recovery rates (16-80%) until 21 days. It was concluded that the susceptibility to M. yokogawai infection is different by strains of mice but it can be elevated by prednisolone injection probably due to suppression of Immune respon3e3 in ICR mice.

• Parasites, Hosts and Diseases
• /
• v.36 no.4
• /
• pp.217-225
• /
• 1998

A scanning electron microscopic study was performed to observe surface ultrastructures of excysted metacercariae and adults of Metagonimus miyatai. Metacercariae were collected from the scale of the pale chub (Zacco platypus). and adult flukes were harvested 1-4 weeks after infection to rats. In excysted metacercariae, the oral sucker was devoid of tegumental spines and had type I and type II sensory papillae. Anteriorly to the ventral sucker, spines were dense and digitated into 5-7 points, whereas near the posterior end of the body spines were sparse and digitated into 2-3 points. In one-week adults, 7 type II sensory papillae were arranged around the lip of the oral sucker. and at inner side of the lip one pair of small and two pairs of large type I sensory papillae were seen on each side. The distribution of tegumental spines was similar to that of metacercariae, but they were more differentiated with 9-11 pointed tips. In two- to four- week old adults, the surface ultrastructure was nearly the same as in one-week old adults, however, sperms were frequently seen entering into the Laurer＇s canal. Conclusively, the surface ultrastructure of M. miyatai was generally similar to that of M. yokogawai, however, differentiation of tegumental spines and distribution of sensory papillae around the oral sucker were different between the two species. which may be of taxonomic significance.

• Parasites, Hosts and Diseases
• /
• v.35 no.4
• /
• pp.259-264
• /
• 1997

This study was carried out to determine whether dermal mast cell responses to Parasoninn westemoni in an abnormal host, the mouse, were dependent on the site of metacercarial inoculation. In mice during subcutaneous infection, the number of der- mal mast cells were increased significantly (p<0.05) at the first week ($38.3/\textrm{mm}^2$) and then persisted at a high level until the sixth week ($45.2/\textrm{mm}^2$) of infection compared with PBS- injected (control) mice (range: $19.4-25.1/\textrm{mm}^2$). In mice during oral infection, the number of dermal mast cells were increased significantly (p<0.05) at two weeks ($33.5/\textrm{mm}^2$) after infection and remained at these levels thereafter compared loth non-infected (control) mice (range: $17.4-22.3/\textrm{mm}^2$). In mice both during subcutaneous and oral infection, the recruited dermal mast cells showed extensive degranulation at the second week (68.4%) and 60.7%, respectivelyl, reached a peak at the third week (81.4%, and 92.1%, respectively) and then declined slightly thereafter. By contrast, in both control mice, about 10% of dermal mast cells were degranulated. In conclusion, this study suggests that dermal mast cell responses to p. westemcni in mice are dependent on cutaneous sensitization by larval excretory-secretory antigens, irrespective of infection route.

• Parasites, Hosts and Diseases
• /
• v.35 no.4
• /
• pp.277-282
• /
• 1997

The only observed morphological difference between Spirometra erinqsei and S. mcnsonoides is the uterine shape of the mature proglottid. Two species of worms are thought to be evolutionarily closely related. Biomolecular colnparison of the ho worms by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was conducted to observe the genetic distance. The 285 rDNA, mitochondrial cytochrome c oxidase subunit I (mCOI), and ribosomal internal transcribed spacer 1 (ITSI) fragments were obtained from the worms by PCR. The PCR products were cleaved by 5 four-base pair restriction enzyme combinations (Msp I, Hae III, Alu I, Cfo I, Rsa I) , electrophoresed and analyzed with PAUP 3.1.1. The fragment Patterns or 285 rDNA and Lni demonstrated that two worms were in identical systematic tree with bootstrap number 94 and 100, respectively As for mCOI, bootstrap number was 74 in a different tree. Above results are indicative of recent common ancestry between S. etinocei and S. mansonoides.

• Parasites, Hosts and Diseases
• /
• v.35 no.4
• /
• pp.239-244
• /
• 1997

Genus Metasonimus has been a subject of taxonomic debates for several years. In morphological aspects, M. vokogawci has been thought to have three subtypes, namely Yokogawa type (M. yokogawai in strict sense) , Miyata type and Koga type. But dif- ferences in the intestinal pathology induced by these subtypes have not been studied yet. In this study we compared the pathological reactions inducted by M. yokoBnwai and Metcgonimus Miyata type using proliferating cell nuclear antigen (PCNA) index. Metacercariae (Mc) of M. yokogcuani were collected by artificial digestion of Plecoslossw oLtiveLis and Mc of Metngonimus Miyata type were collected from Zacco pEntvpus. Three hundreds Mc of each species were infected orally to ICR mice. The mice were sacrificed at 3, 6. 10. 16 and 23 days after infection and the small intestines were resected into three portions (proximal. middle, and distal) . Immunohistochemical staining for PCNA was done using PC-10 (DAKO-PCNA, CA, USA) The PCNA indices in M. Wokosnwci infected group on the 6th and 23rd day after infection were lower than in the control and Miyata type infect ed groups (p < 0.05) from all of the three intestinal regions. On the other hand, the control group and Ifetngonimus Miyata type infected group did not make any differences in PCNA indices. The villus/crypt WIC) ratio was also decreased significantly in M. Wokogcwni infected mice but not in Metagonimus Miyata type infected ones. It is suggested that M. wokogawci induce villous atrophy through a decrease in the cell proliferation at the crypt. The results of this study suggested that M. WokoBnwai induce more serious intestinal pathology than Metcsonimuf Miyata type.

• Korean Journal of Weed Science
• /
• v.30 no.4
• /
• pp.390-395
• /
• 2010

This study was conducted to predict reduction of soybean yield as affected by different densities of Cuscuta pentagona. All data were fitted to Cousens' rectangular hyperbola model to estimate parameters for predicting soybean yield loss. The yield of soybean in the various densities (1 to 48 plants $m^{-2}$) of C. pentagona reduced by 80.3 to 99.7%, respectively. Among yield components, number of pods was the most significantly influenced by weed interferences. The prediction model for soybean yield as affected by weed competition was as follows: Y= 274.6783/(1+4.3522X), $r^2$=0.999 in C. pentagona. Economic threshold levels calculated using cousens' equation was 0.004 plants $m^{-2}$ in C. pentagona.

• Journal of Korean Society of Forest Science
• /
• v.96 no.3
• /
• pp.295-299
• /
• 2007

Resistance to chestnut gall wasp (Dryocosmus kuriphilus) of Korean prevailing chestnut cultivars, new cultivars released by Korea Forest Research Institute (KFRI), and local cultivars by growers was investigated to select optimal cultivars suitable for main chestnut producing areas. During three years investigated from 2004 to 2006, we could find no damage by chestnut gall wasp in any cultivars of test sites located in Gongju and Chungju of the central area. However, most cultivars of Gwangyang, Sancheong and Hapcheon sites located in the southern area showed a lot of damage by chestnut gall wasp. Hapcheon was most severe in comparison with regional damage by chestnut gall wasp. From comparison among cultivars, Kwangeun, Sandae, Eunsan and Idae released by KFRI showed no damage suggesting the highest resistant cultivars. On the contrary, over 20% in total damage by chestnut gall wasp was investigated in Tanzawa, Riheiguri, Kurakata-amaguri, Pyeonggi, Gwangdeok, Seil, Sinipyeong and Yumabyuni suggesting susceptible cultivars. In damage by chestnut gall wasp according to investigated position within tree, weak shoot was more severe than bearing shoot. Damage by chestnut gall wasp of major cultivars in Gwangyang, Sancheong and Hapcheon sites was remarkably decreased in 2006, and it seems to be caused by biological control by natural enemies such as Torymus sinensis.

• Research in Plant Disease
• /
• v.15 no.3
• /
• pp.209-216
• /
• 2009

During the period of June, 2005 to May, 2008, 44 host plants infected with powdery mildew were collected in the Jeon-ju and Jang-su districts of Jeonbuk province and in the Jang-sung district of Jeonnam province. The hyperparasites, Ampelomyces were confirmed in 12 plant species. Most of the pycnidium shapes of Ampelomyces were circular or oval shaped, and the sizes were different even within the same host plant, and also the color of pycnidium was ranged from light brown to dark brown. Ampelomyces species were isolated from 4 hosts including Impatiens balsamina L., Cucurbita pepo, Rudbeckia laciniata var. elatier and Youngia sonchifolia, and thus the most appropriate 12 Ampelomyces strains for the current experiment were selected. When analyzing the selected 12 strains' incubational and nutritional characteristics, the malt extract agar was the most appropriate media. When investigating the effect of osmotic pressure on the spore germination, 0.15M NaCl concentration was the optimum germination concentration. When the isolated Ampelomyces sp. was tested in-vitro, it was found to be effective to control in other plant pathogens, isolated Ampelomyces showed no pathogenicity to the plant. strains isolated . studied on rDNA ITS sequence analysis. The rDNA ITS sequence data of Ampelomyces sp. isolate BSLAH16 from Impatiens balsamina L. were analyzed and identified.

• Parasites, Hosts and Diseases
• /
• v.30 no.1
• /
• pp.43-48
• /
• 1992

Paragonimus westermani is a common fluke in Uorea. The present study aimed to observe the cell mediated immune response in experimental paragonimiasis of mice. The mouse (BALB/c) was orally inoculated with 40 metacercariae of P. westermani from Cambaroides similis. During the infection (1, 2, 4, 6 weeks) of mouse, blastogenic response of splenic Iymphocytes to P. westermani adult antigen, metacercaria antigen, and PHA were observed. Sera from infected and noninfected mice added to normal mouse splenic Lymphocytes with or without PHA. The blastogenic response of splenic Lymphocytes to PHA was reduced after 1 week of infection. However after 6 weeks of infection, the response was restored to the control level. The blastogenic response of splenic Iymphocytes to P. westermani adult or metacercaria antigen increased significantly on 1 week after infection, and maintained up to 6 weeks after infection. The response of non-infected mice was suppressed by addition of the infected mouse serum. The present results suggested that cellular immunity was involved in P. westermani infected mice and that P. westermani anti.serum inhibited proliferation of T Iymphocytes.