• BMB Reports
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• v.53 no.10
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• pp.521-526
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• 2020

Endogenous retroviruses (ERVs) are retrotransposons present in various metazoan genomes and have been implicated in metazoan evolution as well as in nematodes and humans. The long terminal repeat (LTR) retrotransposons contain several regulatory sequences including promoters and enhancers that regulate endogenous gene expression and thereby control organismal development and response to environmental change. ERVs including the LTR retrotransposons constitute 8% of the human genome and less than 0.6% of the Caenorhabditis elegans (C. elegans) genome, a nematode genetic model system. To investigate the evolutionarily conserved mechanism behind the transcriptional activity of retrotransposons, we generated a transgenic worm model driving green fluorescent protein (GFP) expression using Human endogenous retroviruses (HERV)-K LTR as a promoter. The promoter activity of HERV-K LTR was robust and fluorescence was observed in various tissues throughout the developmental process. Interestingly, persistent GFP expression was specifically detected in the adult vulva muscle. Using deletion constructs, we found that the region from positions 675 to 868 containing the TATA box was necessary for promoter activity driving gene expression in the vulva. Interestingly, we found that the promoter activity of the LTR was dependent on che-1 transcription factor, a sensory neuron driver, and lin-15b, a negative regulator of RNAi and germline gene expression. These results suggest evolutionary conservation of the LTR retrotransposon activity in transcriptional regulation as well as the possibility of che-1 function in non-neuronal tissues.

• Parasites, Hosts and Diseases
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• v.51 no.2
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• pp.155-163
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• 2013

This study aimed to evaluate the efficacy of fructose-1,6-bis phosphate aldolase (SMALDO) DNA vaccination against Schistosoma mansoni infection using different routes of injection. The SMALDO has been cloned into the eukaryotic expression vector pcDNA3.1/V5-His TOPO-TA and was used in injecting Swiss albino mice intramuscularly (IM), subcutaneously (SC), or intraperitoneally (IP) ($50{\mu}g/mouse$). Mice vaccinated with non-recombinant pcDNA3.1 served as controls. Each group was immunized 4 times at weeks 0, 2, 4, and 6. Two weeks after the last booster dose, all mice groups were infected with 80 S. mansoni cercariae via tail immersion. At week 8 post-infection, animals were sacrificed for assessment of parasitological and histopathological parameters. High anti-SMALDO IgG antibody titers were detected in sera of all vaccinated groups (P<0.01) compared to the control group. Both the IP and SC vaccination routes resulted in a significant reduction in worm burden (46.2% and 28.9%, respectively, P<0.01). This was accompanied by a significant reduction in hepatic and intestinal egg counts (41.7% and 40.2%, respectively, P<0.01) in the IP group only. The number of dead eggs was significantly increased in both IP and IM groups (P<0.01). IP vaccination recorded the highest significant reduction in granuloma number and diameter (54.7% and 29.2%, respectively, P<0.01) and significant increase in dead miracidia (P<0.01). In conclusion, changing the injection route of SMALDO DNA vaccination significantly influenced the efficacy of vaccination. SMALDO DNA vaccination via IP route could be a promising protective and antipathology vaccine candidate against S. mansoni infection.

• International Journal of Industrial Entomology and Biomaterials
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• v.16 no.1
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• pp.21-27
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• 2008

The expression of heat shock protein genes (Hsp 70, Hsp 40, Hsp 20.8 and Hsp 20.4) against thermal stress in silkworm Bombyx mori was performed through semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Upon exposure of silkworm to two temperature regimes ($38^{\circ}C$ and $42^{\circ}C$), significant change in the expression of Hsp gene was observed as compared to the control. Hsp 70 and Hsp 40 showed increased expression than the small heat shock protein genes Hsp 20.8 and Hsp 20.4. The Hsp 70 showed increased expression during the recovery period as compared to 1 hr thermal treatments ($38^{\circ}C$/1 hr and $42^{\circ}C$/1 hr). Whereas, Hsp 40, Hsp 20.8 and Hsp 20.4 genes showed higher expression level at initial stages that later gradually decrease during recovery period. Tissue specific expression of Hsp 70 showed variation in the level of expression amongst the tissues. The mid gut and fat body tissues showed higher expression than the cuticle and silk gland tissue. The Hsp 70, Hsp 40 gene expression was analyzed in thermotolerant (Nistari) and thermo susceptible silk worm strain (NB4D2) and results showed significant variation in their expression level. The Nistari showed higher expression of Hsp 70 and Hsp 40 genes than the NB4D2. These findings provide a better understanding of cellular protection mechanisms against environmental stress such as heat shock, as these Hsps are involved in an organism thermotolerance.

• Korean Journal of Veterinary Research
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• v.33 no.4
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• pp.679-691
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• 1993

As a series of studies to investigate the effect of immunosuppression on Ascaris suum infection in undefinitive hosts, a delicate relationship between host and parasite, rabbits were divided into experiment 1(control group) and experiment 2(immnunosuppressive group treated with prednisolone acetate) and inoculated with a single dose of 5,000 embryonated A suum eggs. The recovery rates, sizes and morphology of the larvae and immunological responses in the rabbits were chronologically monitored according to somatic migration. In both experiments, the larvae failed to develop into the adults, but young adults in the experiment 2 grew somewhat faster and survied later than those in the experiment 1. The mast cells of small intestinal mucosa and mesenteric lymph nodes and the goblet cells of small intestinal mucosa in the worm detected cases of experiment 2 decreased remarkably in number comparing with those of experiment 1. Considering the experimental results. the expulsion mechanism of somatic migrant larvae may he related to the temporary increasing tendency of the mast cells, the goblet cells, T-cells of mesenteric lymph nodes and spleens, eosinophils in peripheral blood, degranulation rates of peritoneal mast cells and the migration inhibition rates of leucocytes. In addition, patent infection of A suum in the rabbits was not obviously observed despite of immunosuppression by prednisolone acetate.

• Parasites, Hosts and Diseases
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• v.29 no.4
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• pp.371-380
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• 1991

The effects of peritoneal exudate cells(PEC) and sera of athymic nude and DS mice infected with Clonorchis sinensis metacercariae or sensitized by injection of metabolic products into footpad on transfer of immunity against the fluke to the syngeneic mice were studied. There was no significant difference in eggs per gram pattern between the sensitized and control groups, and between nude and DS mice. However, the worm burdens were slightly greater in nude mice than in DS mice. Also, a few plaque forming cells were found in only DS mice given PEC and serum from Group II DS mice. In the light of these results, it is likely that PEC and sera of nude or DS mice which are deficient, at least partially, in the cellular immune system are unable to transfer immunity against C. sinensis to syngeneic recipients.

• Parasites, Hosts and Diseases
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• v.58 no.4
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• pp.431-443
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• 2020

Echinostoma mekongi n. sp. (Digenea: Echinostomatidae) is described based on adult flukes collected from humans residing along the Mekong River in Cambodia. Total 256 flukes were collected from the diarrheic stool of 6 echinostome egg positive villagers in Kratie and Takeo Province after praziquantel treatment and purging. Adults of the new species were 9.0-13.1 (av. 11.3) mm in length and 1.3-2.5 (1.9) mm in maximum width and characterized by having a head collar armed with 37 collar spines (dorsal spines arranged in 2 alternative rows), including 5 end group spines. The eggs in feces and worm uterus were 98-132 (117) ㎛ long and 62-90 (75) ㎛ wide. These morphological features closely resembled those of Echinostoma revolutum, E. miyagawai, and several other 37-collar-spined Echinostoma species. However, sequencing of the nuclear ITS (ITS1-5.8S rRNA-ITS2) and 2 mitochondrial genes, cox1 and nad1, revealed unique features distinct from E. revolutum and also from other 37-collar-spined Echinostoma group available in GenBank (E. bolschewense, E. caproni, E. cinetorchis, E. deserticum, E. miyagawai, E. nasincovae, E. novaezealandense, E. paraensei, E. paraulum, E. robustum, E. trivolvis, and Echinostoma sp. IG). Thus, we assigned our flukes as a new species, E. mekongi. The new species revealed marked variation in the morphology of testes (globular or lobulated), and smaller head collar, collar spines, oral and ventral suckers, and cirrus sac compared to E. revolutum and E. miyagawai. Epidemiological studies regarding the geographical distribution and its life history, including the source of human infections, remain to be performed.

• Parasites, Hosts and Diseases
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• v.61 no.3
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• pp.251-262
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• 2023

Schistosomiasis causes significant morbidity and mortality worldwide. This study aimed to assess the effect of schistosomula lung antigen preparation (SLAP) and soluble egg antigen (SEA) on a murine schistosomiasis mansoni model. Ninety laboratory-bred male Swiss albino mice were divided into 6 groups. Two doses of the vaccine were given at 2-week intervals. All mice were subcutaneously infected with 80±10 Schistosoma mansoni cercariae 2 weeks after the last vaccination dose. They were sacrificed 7 weeks post-infection. Parasitological and histopathological studies were conducted to assess the effect of inoculated antigens (single or combined). The results showed that the combination of SLAP and SEA (combination group) led to a significant reduction in worm burden (65.56%), and liver and intestine egg count (59% and 60.59%, respectively). The oogram pattern revealed a reduction in immature and mature eggs (15±0.4 and 10±0.8, respectively) and an increased number of dead eggs in the combination group (P<0.001). In terms of histopathological changes, the combination group showed notably small compact fibrocellular egg granuloma and moderate fibrosis in the liver. A high percentage of destroyed ova was observed in the intestine of the combination group. This study demonstrates for the first time the prophylactic effect of combined SLAP and SEA vaccine. The vaccine induced a significant reduction in the parasitological and pathological impacts of schistosomiasis mansoni in hepatic and intestinal tissues, making it a promising vaccine candidate for controlling schistosomiasis.

• Journal of Sericultural and Entomological Science
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• v.15 no.2
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• pp.9-14
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• 1973

In order to find out effects of the generative power of silk worm moth which have been brought up in the high temperature accommodation at their pupa stage. For this specific study, 9 different kinds of male silk worms have been selected as specimen. All those specimen were brought up in the normal temperature at their larvae stage and after the pupation period they have been accommodated in the condition of high temperature for a certain length in accordance with the study programme. Afterwards, those mlae specimen were copulated with Suwon jam 103${\times}$104 which were all brought up in normal conditions. This study was carried out to find the copulation function as well as the ratio of unfertilized eggs(male sterility test). Results of study have been revealed as follows: 1) Although some differences were observed, male pura which have been brought up in the condition of high temperature shown the low rate of unfertilized eggs rather than those were brought up in the normal conpition. 2) In this group the eclosion(emergency) has been found to be poor rather, than those specimen brought up in normal conditions. 3) The copulation function of Moran, Daedong, J124 and C108 specimen were found to be poor than those of Suwon jam. 4) Fertility rate of Moran, Daedong, J124 and C108 was found to be around 65%. This figure is rather lower than what we normally expect. 5) Unfertilized egg ratio of Moran, Daedong and C108 were found to be around 20% if they were brought up in the condition of high temperature for one day from the time of pupation: 40% at 2 days, and 70% at 3 days duration. More than 3 days treatment has shown no progress in the unfertilized egg ratio. 6) One day's treatment for the pupa at the later stage has shown the unfertilized egg ratio of about 10%; 20% at 2 day's treatment, 35% at 3 day's treatment, 40-60% at 4 day's treatment, more than 60% at 5 day's treatment, and the 70% of fertilized egg ratio was only observed when the treatment days come to 7 days. It was understood that the unfertilized egg ratio was high at the antepupa stage rather than that of post-pupa stage. 7) According to the result of observation the sperm in copulatory pouch and seminal receptacle out of the normal female silk worm which have been copulated with the male brought up in the condition of high temperature at their moth stage. The reproduction system found in the control zone has been found to be normal and the sperm is amountful and active in motion while the sperm found in the treatment to be limited in amount and slow in motion. The observation was made within 5 hours from the copulation. 8) According to the result of observation of sperm of seminal receptacles of the female silkworm moth, and according to that observation of sperm in the seminal receptacle in female silkworm moth, the amount of sperm and mobility in the female moth brought up in high temperature were poor comparing that were brought up in normal temperature zone. Some of them are even found to be no trace of such. 9) Appearance and mosle of the copulatory organ of the male silkworm moth was found to be no anatomical change. 10) Testis of the later pupa stage which was brought up in the high temperature was found to be almost net developed to anucleate sperm and they are degenerated at stage of between maturation division and sperm abnormal stage. Mean time at control zone, the formation of anucleate sperm was already observed.

• Applied Microscopy
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• v.38 no.1
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• pp.11-19
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• 2008

To examine the effect of the electrolyzed alkaline reduced water (ERW) on animal immunity, by employing Echinostoma hortense that is a parasite in the small intestine, the immune response of C57BL/6 was examined. To C57BL/6 mice, Echinostoma hortense metacercaria 15 per animal was in oculate dorsally, the worm was collected after 2 weeks, and the change of goblet cells and mast cells in the mucosa of small intestine was examined, and by using a protein chip, the change of cytokines in the serum was compared and observed. As a result, average 8.3 worms were collected from the C57BL/6 mice infected with E. hortense, and in the group fed with the ERW, average 10 worms were collected. In regard to the examination of the change of goblet cells, in the experimental group infected with E. hortense and fed with the ERW, average 4.3 worms per villus were detected, hence, it was found that the expression of goblet cells was low (p<0.001). Regarding the examination of the change of mast cells, similarly, in the group infected with E. hortense and fed with the ERW, average 11 worms per villus were detected, and it appears to be less than control group (p<0.001). Regarding the expression of cytokines in mouse serum, in comparison of the experiment group infected with E. hortense and control group, in the expression of the Th1 cytokines IL-6, IL-$1{\beta}$, IFN-${\gamma}$, TNF-${\alpha}$, and IL-2, and the Th2 cytokines IL-4, IL-5, IL-10, and IL-13, a significant difference was not detected. In our study, it was found that in the infection of E. hortense, the ERW mediates its effect on the number of goblet cells and mast cells in the intestinal mucosa, and simultaneously, the worm expulsion was delayed, and thus the conclusion that the ERW mediated its effect on the intestinal immunity of mice was obtained.

• Parasites, Hosts and Diseases
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• v.27 no.3
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• pp.187-196
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• 1989

The effects of gamma irradiation on the survival and development of C. sinensis metacercariae were studied to evaluate the feasibility of irradiation as a control measure for clonorchiasis. Pseudorasbora parve were collected at an endemic river of clonorchiasis and were used for irradiation of the fluke in three schemes. The first (Scheme 1) was irradiation of the isolated metacercariae from the fish followed by infection to experimental rats. The second (Scheme 2) was irradiation of the fish, and then the metacercariae were isolated and in(ected to rats. The third (Scheme 3) was irradiation on the rat livers after infection with normal metacercariae. Irradiation doses varied from 5 to 100 Gy for Schemes 1 and 2, and 10 to 25 Gy for Scheme 3. The rats were sacrificed 2 to 6 weeks after infection. In Scheme 1, the metacercariae irradiated at 50 Gy failed to survive in the rats after 2 or 6 weeks. However, 1 to 44% of the metacercariae irradiated at 5∼30 Gy survived. The estimated LD50 of Scheme 1 was 16.5 Gy. The flukes irradiated in Scheme 2 survived better than those in Scheme 1. The average worm recovery rate in 50 Gy was 28%(7∼39% individually). Increasing the dose up to 100 Gy brought a remarkably low survival rate of an average 1%(0∼3% individually). The LD50 of Scheme 2 was 47.5 Gy. Worm recovery rates in the 10 Gy group of Scheme 3 were 21∼39%, and those in the 25 Gy group were 2% and 34%. Although the metacercariae were irradiated, all of the recovered worms were morphologically normal. Only the worms irradiated with 10 Gy or 25 Gy after 9 days from infection in Scheme 3 showed underdeveloped testes and seminal receptacle. The present results suggest that irradiation of the fish by 100 Gy could be adopted as a control measure for clonorchiasis.