• Parasites, Hosts and Diseases
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• v.24 no.2
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• pp.109-114
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• 1986

In order to observe the growth and development of Fibricola seoulensis metacercariae, the tadpoles of Rana nigromaculata were experimentally infected with the cercariae. The meta cercariae of various developmental stages were recovered from the tadpoles after 2 to 65 days of infection. They were prepared for morphological observation, and were given orally to mice to observe their infectivity. The following results were obtained. 1. All of the tadpoles exposed to the cercariae were observed to harbour the larvae in their abdominal cavity. 2. The young metacercariae of 2 days after infection were $121.1{\mu}m$ long and $63.3{\mu}m$ wide. They grew linearly for the first 14 days to be $262.0{\mu}m$ long and $166.4{\mu}m$ wide. Thereafter, no more growth recognized until 65 days. 3. The larvae of 2 days old were similar with cercarial body and had 2 suckers, a pharynx, 2 ceca and a primordium of germ cells but no tribocytic organ. On the 8th day, they had tribocytic organ, and their morphology resembled that of mature metacercariae. 4. The metacercariae younger than 10 days could not infect the mice. Only the metacercariae older than 14 days had infectivity. The recovery rates increased by the age of metacercariae from 19.0% in 14 days old to 70.0% in 40 days old. Above findings indicate that the tadpole is indispensable for metacercarial development and it needs at least 2 weeks for maturation. The tadpole is a pivotal host in the life cycle of F. seoulensis for connection between the snail and the frog.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.664-672
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• 2015

In order to develop new immuno-stimulating ingredients from mature leaves of green tea, crude polysaccharides were isolated from pectinase digests of tea leaves (green tea enzyme digestion, GTE-0), after which their immuno-stimulating activities and chemical properties were examined. GTE-0 mainly contained neutral sugars (54.9%) such as glucose (14.2%), arabinose (12.2%), rhamnose (11.1%), and galacturonic acid (45.1%), which are characteristic of pectic polysaccharides. The anti-complementary activity of GTE-0 was similar to that of polysaccharide K (used as positive control). Number of morphologically activated macrophages was significantly increased in the GTE-0-treated group. GTE-0 significantly augmented $H_2O_2$ and reactive oxygen species production by murine peritoneal macrophage cells in a dose-dependent manner, whereas production of nitric oxide showed the highest activity at a dose of $100{\mu}g/mL$ among all tested concentrations. Murine peritoneal macrophages stimulated with GTE-0 showed enhanced production of various cytokines such as interleukin (IL)-6, IL-12, and tumor necrosis factors-${\alpha}$ in a dose-dependent manner. Further, GTE-0 induced higher phagocytic activity in a dose-dependent manner. In ex vivo assay for cytolytic activity of murine peritoneal macrophages, GTE-0-treated group showed significantly higher activity compared to the untreated group at an effector-to-target cell ratio of 20. The above results lead us to conclude that polysaccharides from leaves of green tea have a potent immuno-stimulating effect on murine peritoneal macrophage cells.

• Applied Microscopy
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• v.38 no.2
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• pp.141-148
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• 2008

Nitric oxide (NO) is an important regulator of renal blood flow, glomerular hemodynamics, and tubule transport processes in the kidney. There is also evidence that NO is involved in cell cycle regulation and mitotic division. During development the nNOS expression pattern differs from that observed in adult animals. However, little is known about temporal and spatial patterns of nNOS expression in the developing kidney. The purpose of this study was to establish the time of expression and the distribution of nNOS in the developing rat kidney. Kidneys from 14-, 16-, 17-, 18-, and 20-day-old fetuses, 1-, 4-, 7-, 14-, and 21-day-old pups, and adult animals were preserved and processed for immunohistochemistry. In the adult kidney, nNOS was detected in the parietal epithelium of Bowman s capsule, macula densa, descending thin limb and inner medullary collecting duct. nNOS immunoreactivity appeared first in the distal tubule anlage at 15 days of gestation, and in all epithelial cells of developing thick ascending limbs (TAL) as well as macula densa of 17- and 18-day-old fetuses. From 20 days of gestation to 14 days after birth, nNOS was expressed in the newly formed cortical TAL, which are located in the medullary ray, whereas in mature TAL of juxtamedullary nephrons, nNOS immunolabeling gradually decreased in intensity and became restricted to the macula densa. In inner medullary collecting ducts, nNOS immunoreactivity appeared first at 7 days after birth in the papillary tip and gradually ascended to the border between outer and inner medulla. In the descending thin limb and parietal epithelium of Bowman's capsule, weak nNOS immunoreactivity was observed at 14 days after birth and labeling gradually increased to adult levels at 21 days after birth. These results suggest that differential expression of nNOS in the developing kidney is an important physiological regulator of renal function during kidney maturation.

• Development and Reproduction
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• v.5 no.1
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• pp.47-52
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• 2001

Predetermination of sex in livestock of offpring is in great demand and is of critical importance to providing for the most efficient production of the animal ariculture. Such a sexing techlology would also enhance the economy of conventional artificial insemination(AI) and aid the porcine industry. The purpose of this study was to evaluate the efficiency of enriching X-bearing porcine sperm using discontinuous percoll gradients and PCR mefhod. Semen was collected from mature boars of proven fertility center (AI center KimHae). Sperm was leaded on the isotonic discontinuous percoll gradient and then it was centrifuged at 120 ${\times}$ g for 20 minutes. After centrifugation, sperm included in each fraction were recovered (7${\times}$10$^6$ sperms/ml) and then sperm genomic DNA was extractedfor the PCR. SRY gene was used to evaluate the ratio between X and Y sperm in the separated fractions. Ju viro ffrtilization wascarried out by adding the unseparated sperm (control) or separated (experimental poop) to the matured oocytes in TCM-199. Embryos for sex determination were obtained at 2 cell stage and then was used for SRY gene amplification. After centrifugation of discontinuous percoll gradient, the most motile sperm was obtained at 95% fiaction (94.4% ${\pm}$ 5.1%, p < 0.01). The PCR analysis evaluated that 30%, 50% and 65% fractions were Y sperm rich, whereas 80% and 95% fractions were X sperm rich. PCR analysis with each porcineembryo showed that 33.3% of control and 66.7% of experimental group were determined as female embryos. In conclusion, in vitro matured oocytes inseminated with sperms (95% fraction) prepared by percoll gradient centrifugation showed high fertilization rates and female embryos than control sperms.

• Journal of Plant Biology
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• v.38 no.1
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• pp.95-105
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• 1995

Complete microsporogenesis of Hibiscus syriacus L. were carried out employing LM, TEM, and SEM to investigate the pollen ontogeny that undergoes considerable structural differentiation. The process first began with several cell diYisions in the anther primordium that produces 3 different tissues of epidennal, archesporial, and connective tissues. Only archesporial tissue involved further differentiation into the tapetum and formation of reproductive cells, pollen mother cells (PMC). The tapetum and PMC were closely associated with each other structurally and metabolically by exhibiting numerous plasmodesmata, mitochondria, and many small vacuoles in their dense cytoplasm. A callosic wall began to surround the PMC while meiosis took place in the PMC to produce 4 microspores. When thick callose encircled each microspore as a frame, the sporodenn development initiated from the plasma membrane of a pollen grain in a tetrad. The first fonned sporoderm layer was bacules and tectum of sexine that originated from the plasma membrane. After the dissolution of a callose, further development Qf sporoderm continued in the order of nexine 1, nexine 2, and intine layer. The nexine layer was thicker (ca. $2-3.5\;\mu\textrm{m}$) than the intine layer whose thickness was about $0.9-1.5\;\mu\textrm{m}$. Upon completion of the sporoderm development, that is after intine formation, spines and apertures of pollen surface ornamentation initiated from the tectum. Spines were dimorphic, about $4-9\;\mu\textrm{m}\;an;15-20\;\mu\textrm{m}$ in length, and no basal cushion was detected. The mature pollen grains ranged $100-200\;\mu\textrm{m}$ in diameter, but their average was about $170\;\mu\textrm{m}$. About 120 spines were observed over the spheroidal pollen surface. Apertures were simple punctures of $2-3\;\mu\textrm{m}$ in diameter and about 50 apertures were arranged somewhat helically over the surface. Comparing such features of form and size of the pollen, sporodenn sculpture and structure, and aperture and spine conditions with known evolutionary trends in the genus Hibiscus, Hibiscus syriacus seemed to possess many advanced features in the sporodenn differentiation.iation.

• Parasites, Hosts and Diseases
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• v.27 no.4
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• pp.231-248
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• 1989

The growth and development of the metacercariae of F. seoulensis cultivated in vitro or on the chick chorioallantois were assessed by comparison with the optimum process of maturation in albino rats and new born chickens. The process of maturation was divided for convenience into six stages: Stage 1 ; cell multiplication, Stage 2; body shaping, Stage 3; separation of genital anlagen, Stage :1 organogeny, Stage 5; gametogony, and Stage 6: oviposition. In Hank's and Tyrode's .solutions, the metacercariae were alive up to 200 days or more at $4^{\circ}C$ without any development. The in vivo maturation process in rats or chicks was as follows: stage 1 from 6 hours; stage 2 from 24 hours; stage 3 from 48 to 72 hours; stage 4 from 3 to 4 days; stage 5 from 4 to 5 days; and stage 6 from 5 to 8 days. Despite unsuccessful infection of the metacercariae to 12 day old chicks, fully mature worms of stage 5 or 6 were recovered from new born chicks (1 to 2 days old), The metacercariae of F. seoulensis grown in vitro were up to stage 3 and no further maturation was observed. Of various media employed, the medium NCTC 109 (Gibco) or NCTC 135(Gibco) supplemented with 20% egg yolk or 20% whole egg macerate or 0.5% yeast was basically required for the earlier development of the fluke. It took 16.1 days(in average) to reach the stage 3 after cultivation. The metacercariae cultivated on the chorioallantoic membranes of 6∼13 day old chick embryo at 37∼38℃ showed their full development up to stage 5 or 6. However, the worms were in general remarkably retarded, compared with those grown in rats or chickens. In the experiments of worm transplant, although the transfer was failed from in vitro culture to in vivo of rats(Per os), the transplants from in vitro culture to the chorioallantois and from the choriollantois to in vivo of rat host were successful with or without development of the transferred worms. In the present study, it was observed that the metacercariae of F, seoulensis can be maintained in vitro media with poor development as well as fully matured in 1 to 2 day-old chicks or on the chorioallantois at a very low rate.