• Parasites, Hosts and Diseases
• /
• v.36 no.2
• /
• pp.99-108
• /
• 1998

The present study was performed to check the viability of eggs, filariform larvae and adults of Strongvloines venezueLensis exposed to various conditions for an in vitro maintenance. The eggs in the feces remained viable for about 25 days at $4^{\circ}C$ and 15 days at room temperature. However, the isolated eggs in sterile saline lost their viability within 24 hr at $4^{\circ}C$. The eggs in morula stage were very sensitive to air drying and rapidly lost their viability (=12 hrs. Filariform larvae survived for a maximum period of 45 days in fecal suspension and 28 days in 0.12% nutrient broth in polyvinyl culture bags maintained at $20^{\circ}C$. On the other hand, those isolated from nutrient broth cultures survived for a maximum period of 32 days in tap water and 22 days in sterile saline at $20^{\circ}C$. The mature adult worms obtained from experimentally infected rats survived maximally for 9 days in serum supplemented (10% rat-serum) 0.12% nutrient broth and 4 days in serum free nutrient broth at $37^{\circ}C$ while the culture media were changed at an alternate day. The adult female worms deposited fertile eggs in serum supplemented and serum free nutrient broth cultures, however, the hatched larvae (Ll) were not able to develop to the filariform stage in the culture media and found to die within 24 hr of maintenance. The present findings on an in vitro maintenance of different stages of 5. uenezueLetis may provide useful information for biological and biochemical studies with Strongyloines species. Key words: Strongvloides venezuelensis. viability in vitro maintenance, free-living filariform larvae (L3), embryonation of eggs

• Parasites, Hosts and Diseases
• /
• v.31 no.1
• /
• pp.31-36
• /
• 1993

This study was performed to evaluate differences of T cell subsets according to the injection period of recombinant mouse $interferon-{\gamma}{\;}(IFN-{\gamma}$ in acute Toxoplasma gondii infection. Each mouse was infected intraperitoneally with 100 cysts of Beverley strain T. gondii, and injuten with $5{\;}{\times}{\;}10^4$ units of $IFN-{\gamma}$ every other day two tares. The percentage of Thy-1, 2 cells and L3T4/Ly-2 cell ratio were significantly increased in the mice that received two doses of $IFN-{\gamma}$ on days 2 and 0 before infection, or days 0 and 2 after infection. The percentage of Ly-2 cells decreased in the $IFN-{\gamma}$ injected groups at th\ulcorner 3rd and 4th week after infection. The results suggest that administration of $IFN-{\gamma}$ to T gonnii-infected mice improves the changed population of T cell subsets to a normal state, especially when $IFN-{\gamma}$ was infected just after the infection.

• Parasites, Hosts and Diseases
• /
• v.27 no.3
• /
• pp.203-212
• /
• 1989

The development of Echinestcma cinetorchis in several snail species reared in laboratory aquaria was observed. The eggs from adult cukes collected from the intestine of rats were cultivated to miracidia, and exposed to Hippeutis sp. snails. Observations were made for cercarial shedding from the exposed snails. The cercariae shed from the snails were again exposed to several species of fresh water snails in order to observe metacercarial formation in the snails and their infectivity to final hosts. The results obtained in this study were as follows: 1. Twenty miracidia were exposed to each snail of Hippeutis sp. About 58.3% of the above snails (7 out of 12) were dead before shedding the cercariae, anti the remainder shed the cercariae for a period of 7 to 9 days before death. 2. Cercarial shedding from the infected snails started from the 25th day after the exposure to mi.acidia, and the total number of cercariae shed per snail was 684 in average (range; 482-904). 3. The sixte of refine developed in the infected Hippeutis sp. snails was 1$, 242{\times}214{\;}{\mu}m$ in average, and the number of rediae per snail was 350 in average (range; 120-510). 4. About 40 to 50 cercariae shed from the Hippeutis sp. snails were each exposed to several species of snails reared in the laboratory. The metacercarial formation was confirmed by dissecting the infected snails, 12 to 16 days after the infection. The infectivity to each snail species was 100% in Hippeutis sp. (recovery rate; 56.7%) and Radix auricuzaria coreana (recovery rate; 66.4%), 66.7% in Physa acute (recovery rate; 37.5%), and 50% in Cipangopaludina sp. (recovery rate; 8.0%), respectively. 5. The swimming cercariae attached first at the cephalo-podial part of the snails and then migrated to the mantle, internal organ s and hemocele areas to form the metacercariae. 6. Adult worms of E. cinetorchis were obtained from the rats infected with the metacercariae encysted in the experimental snails. Summarising the above results, it is suggested that the mud-snail (Cipangopaludina sp.) may play an important role as a source of human infection with E. cinetorchis in Korea, and that several species of fresh water snails are involved in the life cycle as a second intermediate host.

• Parasites, Hosts and Diseases
• /
• v.26 no.4
• /
• pp.229-238
• /
• 1988

In vitro culture of Toxoplasma gondii in HL-60 cells and cell-mediates immunity against Toxoplasma in dimethylsulfoxide(DMSO) -induced HL-60 cells, i.e., differentiation into granulocytes, were pursued. HL-60 calls were treated with various concentrations of DMSO, and 1.3%(v/v) for 3 day incubation was chosen as the optimal condition icy differentiation into granulocytes. The degree of differentiation was assayed in physiological and functional aspects in addition to morphological point. When treated with 1.3% DMSO for 3 days, HL-60 cells did not synthesiar DNA materials beyond background level, and showed active chemotactic response to chemotactic peptide, formal-methionyl-leucyl-phenylalanine(FMLP). Morphologically promyelocytes of high nuclearlcytoplasmic(NIC) ratio changed to granulocytes of relatively low WJC ratio. The relationships between HL-60 cells or DMSO-induced HL-60 cells and Toxoplasma were examined after stain with Giemsa and Buorescent dye (acridine orange). HL-60 cells did not show any sign of torso- plasmacidal activity but showed intracellular proliferation of Texoplasma to form rosette for 72 hr co-culture. In contrast, OMSO-induced HL-60 cells phagocytosed Toxoplasma within 1 hr, and performed a process of intracellular digestion of Toxoplasma thereafter. With the above results, it is suggested that phagosome-Iysosome fusion is one of the critical events for the parasitism by Toxoplasma or for susceptibility of host cells. The in vitro culture system of this study has offered a defined condition to study the protozoan parasite-host cell interactions.

• Parasites, Hosts and Diseases
• /
• v.33 no.1
• /
• pp.9-18
• /
• 1995

The study made an observation on periodicity of oviposition, and the effects of nutrient and salinity in egg un larval development of Aedes togoi, and the results are summarized as follows: The 53.9% mosquitoes of one feeding laid eggs once, 26.9% laid hice and 19.2% laid three times. Autogenous rate of Aedes togoi reared in three different nutrient groups in larval stage was 6.9% in 0.8 mg/larva, 22.5% in 1.6 mg/larva and 44.4% in 2.4 mg/larva. The oviposition rate according to different salinity of the oviposition sites (0%, 0.5%, 1.0%, 2.0% and 4.0%) was 25.2% in distilled water, 36.2% in 0.5% salinity 23.5% in 1.0% salinity and 14.6% in 2.0% salinity. Developing period of the aquatic stage of male Aedes toBoi in $25^{\circ}C$ were shorter (10.73 days) than females (11.85 days). The most effective concentration of salinity for the developing period was 1.0% which took 9.25 days in males and 10.44 days in females. In the developmental status of the follicles according to nutrition in the larval stage, the numbers of follicles of groups fed 0.8 mg, 1.6 mg and 2.4 mg per larva were 180.7, 197.% and 202 respectively. The result of ovary dissection on the 1 with day after emergence, three different nutrition groups were in Christopher's stage IIa mostly; each 71.0%, 61.1% and 39.9% of the total follicles and autogenous females observed.

• Food Science of Animal Resources
• /
• v.40 no.6
• /
• pp.1014-1032
• /
• 2020

This work aimed to investigate the psychobiotic effects of six bacterial strains on the mind and behavior of male Wistar rats. The probiotic (PRO) group (n=7) were rats pre-treated with antibiotics for 7 days followed by 14-day probiotic administration, antibiotics (ANT) group (n=7) were rats treated with antibiotics for 21 days without probiotics. The control (CON) group (n=7) were rats that received sham treatment for 21 days. The six bacterial strains with probiotic properties were mostly isolated from Thai fermented foods; Pedicoccus pentosaceus WS11, Lactobacillus plantarum SK321, L. fermentum SK324, L. brevis TRBC 3003, Bifidobacterium adolescentis TBRC 7154 and Lactococcus lactis subsp. lactis TBRC 375. The probiotics were freeze-dried into powder (6×10⁹ CFU/5 g) and administered to the PRO group via oral gavage. Behavioral tests were performed. The PRO group displayed significantly reduced anxiety level and increased locomotor function using a marble burying test and open field test, respectively and significantly improved short-term memory performance using a novel object recognition test. Antibiotics significantly reduced microbial counts in rat feces in the ANT group by 100 fold compared to the PRO group. Probiotics significantly enhanced antioxidant enzymatic and non-enzymatic defenses in rat brains as assessed using catalase activity and ferric reducing antioxidant power assay, respectively. Probiotics also showed neuroprotective effects with less pyknotic cells and lower frequency of vacuolization in cerebral cortex. This multi-strain probiotic formulation from Thai fermented foods may offer a potential to develop psychobiotic-rich functional foods to modulate human mind and behaviors.

• Asian-Australasian Journal of Animal Sciences
• /
• v.33 no.8
• /
• pp.1242-1251
• /
• 2020

Objective: The 3×3 factorial arrangement was used to investigate if either high water-soluble carbohydrates (WSC) cultivars or suitable time of day that the grass cut could improve nutrient values and in vitro fermentation characteristics. Methods: The 3 cultivars were mowed at 3 diurnal time points and included a benchmark WSC ryegrass cultivar 'Premium', and 2 high WSC cultivars AberAvon and AberMagic, which contained, on average, 157, 173, and 193 g/kg dry matter (DM) of WSC, and 36.0, 36.5, and 34.1 g/kg DM of N during 7th regrowth stage, respectively. The fermentation jars were run at 39℃ with gas production recorded and sampled at 2, 5, 8, 11, 14, 17, 22, 28, 36, and 48 h. The rumen liquid was collected from 3 rumen fistulated cows grazing on ryegrass pasture. Results: High WSC cultivars had significantly greater WSC content, in vitro DM digestibility (IVDMD) and total gas production (TGP), and lower lag time than Premium cultivar. Methane production for AberMagic cultivar containing lower N concentration was marginally lower than that for AberAvon and Premium cultivars. Grass cut at Noon or PM contained greater WSC concentration, IVDMD and TGP, and lower N and neutral detergent fiber (NDF) contents, but CH₄ production was also increased, compared to grass cut in AM. Meanwhile, the effects of diurnal cutting time were influenced by cultivars, such as in vitro CH₄ production for AberMagic was not affected by cutting time. The IVDMD and gas production per unit of DM incubated were positively related to WSC concentration, WSC/N and WSC/NDF, respectively, and negatively related to N and NDF concentrations. Conclusion: These results imply either grass cut in Noon or PM or high WSC cultivars could improve nutrient values, IVDMD and in vitro TGP, and that AberMagic cultivar has a slightly lower CH₄ production compared to AberAvon and Premium. Further study is necessary to determine whether the increase of CH₄ production response incurred by shifting from AM cutting to Noon and/or PM cutting could be compensated for by high daily gain from increased WSC concentration and DM digestibility.

• Parasites, Hosts and Diseases
• /
• v.34 no.1
• /
• pp.21-26
• /
• 1996

An experimental study was carried out to observe the effects of radiation on the infectivity of metacercariae of Gymnophalloines seoi to C3H mice. Oysters, the second intermediate host, were collected from an endemic area, and non-irradiated control, metacercaria-irradiation, and oyster-irradiation groups were prepared . One hundred metacercariae were infected orally to each mouse, and worm recovery rate was compared by groups at 7th day post-infection. In the metacercaria-irradiation group, the worm recovery rate was significantly reduced at radiation doses higher than 200 Gy, and the number of intrauterine eggs significantly reduced at doses over 50 Gy. In the oyster- irradiation group, 50 Gy significantly reduced both the worm recovery rate and number of uterine eggs. In the two groups, no worm was recovered at 1,000 Gy irradiation. Conclusively, irradiation of oysters with 200-1,000 Gy was effective to control infectivity of metacercariae to C3H mice, and could be adopted as a control measure for gymno-phalloidiasis.

• Parasites, Hosts and Diseases
• /
• v.33 no.3
• /
• pp.179-186
• /
• 1995

Human anisakiasis may occur after ingestion of raw marine flesh infected with nematode larvae of Anlsi,hidae. Anisakiasis caused by the migration of the larva into the wall of stomach, small intestine and other portion has been reported in Korea. This prospective study was made of all cases referred to parasitological laboratory in Cheju-do between. Tune 1989 and June 1992. Gastric anisakiasis was confirmed if larvae invading the gastric wall were observed by gastrofiberscopy One hundred and seven cases were diagnosed, most of which were in 30-49 years old. Most of the patients complained acute epigastric pain with history of eating raw marine fish. This symptom usually occurred about 12 hours to 1 day after ingestion of infected marine fish. Edema, erosion or ulcer of the mucosa and hemorrhage from the gastric wall were observed in the involved areas. Ninety larvae removed from the stomach were identified; the larva of Anisqkis siwlex was the most prevalent species, and the Iarva of Pseudntewanoua decipien was also detected. The important species of marine fish from which the patients became infected was demonstrated as yellow corvina, sea eel, ling, cuttle fish, yellowtail and others. Five species of marine fish as a possible source of infection were examined, and Anisakis simplex larvae and Pseunotewqnoua decipirens larvae were collected from the mackerel and rock cod. This study demonstrates that anisakiasis is recognized as a public health problem in Korea.

• Parasites, Hosts and Diseases
• /
• v.32 no.3
• /
• pp.195-200
• /
• 1994

Malaria is estimated to have a worldwide incidence of more than 100 million clinical cases and approximately 1 miuion deaths per year. Korea, although previously tnlown as an endemic area of tertian malaria (Pzosmonin vivax), has been considered free from malaria as there had been no report on indigenous cases since 1984. Recently, however, we experienced an indigenous case of P. viuax infection in a young man who had never been abroad. The patient was a 23-year-old Korean soldier with 18-day history of recurrent fever and chill lasting 4 to 8 hours on alternative days since mid-July 1993. He had lived in Changwon, Hyongsangnam-do, before entering barracks located in Paiu-gun, Kyonggj-do on Jne 1992, and had never been out of Korea. He had no history of blood transfusion nor parenteral use of drugs. The peripheral blood smears showed typical ring forms, trophozoites, and gametocytes of p. uiuox, in addition to mild anemia and thrombocytopenia. After confirmation of the diagnosis, he was treated with hydroxychloroquine and primaquine. Follow-up blood smears no more revealed malaria parasites. It is not certain whether the present case is due to a resurgence of indigenous malaria or a secondary infection from introduced mnuia. Whichever the source of infection the domestic occurrence of mnuia cycle in Korea should be a warning sign in public health point of view.