• The Korean Journal of Ecology
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• v.23 no.4
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• pp.323-329
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• 2000

The allelopathic effects of volatile substances from Chamaecyparis obtusa (S. et Z.) Endl. were examined on the germination and seedling growth of some plant species, and on the population growth of some microorganisms. The germination and seedling growth of the receptor plants were suppressed more severely by leaf and fruit essential oils than by those of other parts. Colonial growth of fungi was severely inhibited by essential oils extracted from leaves and fruits. The development of root hairs of the receptor plants was also severely inhibited by the essential oils. The cortical cells at the root tips of Lactuca sativa L. treated with essential oils showed contraction of the cytoplasm, resulting in plasma membranes becoming detached from the cell walls and the cells metamorphosing irregularly. Accumulation of lipid granules inside the contracted cytoplasm and degeneration of mitochondrial cristae were also observed.

• Journal of Species Research
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• v.11 no.4
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• pp.287-295
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• 2022

Three oxytrichid ciliates, Oxytricha lithofera Foissner, 2016, Pleurotricha curdsi (Shi et al., 2002) Gupta et al., 2003 and Sterkiella tetracirrata Kumar et al., 2015, were isolated from soils and confirmed as new to South Korea. Oxytricha lithofera was identified based on lithosomes, cortical granules, 21-33 adoral zone membranelles, one left (14-21 cirri) and one right (15-18) marginal rows and 5 transverse cirri. Pleurotricha curdsi was identified based on the possession of 2 macronuclear nodules, 2-3 micronuclei, 46-53 adoral zone membranelles, 3 frontal cirri, 5 frontoventral cirri, 5-7 postoral ventral cirri, 2-3 right marginal rows and 5 transverse cirri. Sterkiella tetracirrata was identified with respect 4 macronuclear nodules, 3-6 micronuclei, 25-40 adoral zone membranelles, 3 frontal cirri, 3 postoral ventral cirri, 2 pretransverse cirri, one left (21-30 cirri) and one right (24-30) marginal row and 4 transverse cirri. On the basis of 18S rDNA sequence analyses, we describe the phylogenetic positions of the three species.

• Journal of Species Research
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• v.12 no.4
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• pp.307-312
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• 2023

Oxytricha multilineata, Mixophrya pantanalensis pantanalensis, and Caudiurostyla sinensis were isolated from soil samples collected from Cheongju-si and Yeoju-si, confirmed as new to South Korea. Oxytricha multilineata was distinguished from other congeners by seven dorsal kineties and dorsal bristles about 15 ㎛ long. Mixophrya pantanalensis pantanalensis was characterized by five to seven lithosomes and six dorsal kineties. Caudiurostyla sinensis was characterized by colorless cortical granules present, 10-14 midventral pairs, 7-9 left and 6-9 right marginal rows and four or five dorsal kineties. We determined the ribosomal DNA sequences (including 18S rDNA, ITS1, 5.8S rDNA, ITS2, and partial 28S rDNA) from above three species. And the genetic distances were compared with their congeners.

• The Korean Journal of Zoology
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• v.20 no.2
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• pp.77-92
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• 1977

A study has been made to correlate morphological and biochemical differentiation in the oocytes of a tubiculous polychaete, Schizobranchia insignis. The pressent paper is concerned with an examination of the cytological changes during oogenesis and annual size distribution of oocytes, The oocytes are released from the ovary into the coelomic sac at the end of the oogonial division and grow to a maximum size (180 $\\mu$ diameter). Oogensis takes place continuously throughout a year, although the breeding season is the period between January and March. When the oocytes reach the largest size class, they remain constant in size thereafter and accumulate in the coelomic sac. The nucleolus, which first appears in the oocytes 5-10$\\mu$ diameter, grows in the early stages of oogenesis, becomes maximum in the oocytes 100-120$\\mu$ diameter, and is constant throughout the rest of the pertiod. The nuclelus initially has a single comartment but becomes bipartite prior to vitello genesis. Three types of yolk including lipid droplets, proteid granules and oval granules oof unknown composition form at different times of oogenesis. The lipid droplets and oval granules appear in the early stage, but mainly in the oocytes larger than 80 $\\mu$ diameter. Proteid yolk and cortical granules appear only in the oocytes larger than 80 $\\mu$ diameter Microvilli are abundant in the oocyte 80 $\\mu$ diameter and embedded in the vitelline membranc. In the oocytes 180 $\\mu$ diameter they have retracted from the vitelline membrane.

• Applied Microscopy
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• v.2 no.1
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• pp.7-15
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• 1972

The morphological and fine structural changes during the oogensis of Clonorchis sinensis were studied on the developing ovums in the ovary and ootype with electron microscope. Adult worms were removed from the hepar of the which and previously infected with metacercariae of Clonorchis sinensis. The ovary including the Mehlis' glands and an ootype from adult worm was prefixed for 1-2 hours in 1.25% glutaraldehyde buffered with 0.2M cacodylate at PH 7.2, secondarily fixed for 30 minutes in potassium bicromate and postfixed for an hour in 1% osmic acid buffered with 0.4M cacodylate at PH 7.2. After fixation tissues were dehydrated in an alcohol series, embedded in Epon 812 from propylene oxide and stained with saturated uranyl acetate and $Pn(NO_3)_2$ solution. Material was examined with a Hitachi HS-7S electron microscope. The periphery of the ovary, except for the posterior region, is made up of oogonia. As the oogonia divide they proliferate primary oocytes toward the central part of the ovary. After a period of growth the primary oocyte leaves the ovary and is penetrated by a sperm in the ootype. Sperm penetration immediately activates the primary oocyte to resume its meiotic activity. After the oocytes meiotic activity is completed, the pronuclei fuse to form a single cleavage nucleus which possesses two nucleoli. As the oocytes develop their cytoplamic materials are abundant; small mitochondria are abundant and often their profiles are more unmerous in one part of the cytoplasm than elsewhere; the granular endoplasmic reticulum becomes alveolar-sac form after it leaves the ovary it becomes stratified form. The reticulate Golgi apparatus is apparent in the developed oocyte. A little of cortical granules are distributed inside of the plasma membrane I oogonia and large quantity of cortical granules are arranged just inside of the plasma membrane of the primary oocyte and after fertilization they are disappeared with broken out.

• Applied Microscopy
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• v.30 no.1
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• pp.61-72
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• 2000

Three fertilization envelopes (FE) have been observed after the artificial insemination of U. unicinctus oocytes. The substances of the first fertilization envelope, which is an effective barrier against excessive sperm, come mainly from the surface coat of the oocyte. The secretions of the cortical granules take part in formation of the 2nd fertilization envelope. Histologically, the 3rd fertilization envelope is not amorphous as seen under light microscope, but contains numerous panicles under electron microscope, which would be contributed to harden the envelope by 60 min after the fertilization. With the substantial similarity between the 1st fertilization envelope and the surface coat of the oocyte, and the coincidence of retraction of microvilli and the formation of the 1st fertilization envelope, it is suggested that the microvilli contain the sperm receptors in U. unicinctus. Some granular substances from the distal part of the acrosome diffuse on the surface coat of the oocyte while the acrosomal tubules penetrate into the surface coat. The acrosomal tubules arise from the proximal part of the acrosome and pass through the acrosomal lumen.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.1
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• pp.99-110
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• 1994

One consequence of fertilization in mammals is an increased resistance of the zona pellucida (ZP) to proteases and various chemical reagents. This phenomenon has been called 'zona pellucida hardening' (ZPH), and it is generally accepted that it is caused by the secretory products of cortical granules released by the egg at fertilization. ZP of mouse oocytes maturing in vitro in a chemically defined medium becomes progressively more resistant to solubilization by chymotrypsin ("Spontaneous" ZP hardening). In the present study, it was aimed to find the specificity of spontaneous ZPH in relation to its possible relevance to the cortical reaction and the physiological block to polyspermy. When a maturation inhibitors, cAMP analog(dbcAMP) and phosphodiesterase inhibitor (IBMX) was added to culture medium, it prevent spontaneous ZPH of mouse oocyte during in vitro culture. Thus spontaneous ZPH requires GVBD, since it is prevented by those agents, which inhibit GVBD in vitro. However, culture for 3 hours in the presence of PMA(lOng/ml), a protein kinase C activator, resulted in ZPH without GVBD, thus suggesting that ZPH may be regulated independently apart from the event of GVBD. Pretreatment of mouse oocyte with FBS result in partially inhibitory effect on subsequent spontaneous ZPH. Induction of GVBD in vivo had a inhibitory effect on the spontaneous ZPH, but subsequent spontaneous ZPH. Induction of GVBD in vivo had a inhinbitory effect on the spontaneous ZPII, but had no inhibitory effect on PMA-induced ZPH. Treatment with a microfilament formation blocker(cytochalasin-B) at 1${\mu}g$/ml concentration, resulted in the excellent inhibitory effect on spontaneous ZPH. However cytochalasin-B did not inhibit PMA-induced ZPH. Thus this suggesting that spontaneuse ZPH had a different mechanism from PMA-induced ZPH.

• Korean Journal of Animal Reproduction
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• v.17 no.3
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• pp.183-191
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• 1993

These experiments were carried out to investigate whether the enzyme is involved in zona hardening during normal activatin of the oocytes by sperm, and demonstrate peroxidase activity during in vitro fertilization of oocytes treated with peroxidase inhibitors(250 $\mu$M phenylhydrazine, 28mM sodium sulfite, 350mM glycine ethyl ester and 50mM sodium azide) and tyrosine analogue(12.5mM tyramine). Also, zona soluble properties of the ovarian oocytes incubated for 0, 5, 10 and 15 hr in the presence of pheylhydrazine or tyramine were studied by using $\alpha$-chymotrypsin. The results obtained from these experiments were summarized as follows ; 1. The rates of fertilizatin in control oocytes and oocytes treated with phenylhydrazine or tyramine were 69.8%, 62.3% and 88.2%, respectively. However in vitro fertilization in oocytes treated with three different peroxidase inhibitors, sodium sulfite, glycine ethyl ester and sodium azide, were not induced. The oocytes treated with phenylhydrazine had no significant effect on in vitro fertilization rate as compared to control. However there was a significantly different in fertilization between tyramine treated group and control group(P<0.01). 2. The zona solubility(t50) of control and fertilized oocytes in culture treated with phenylhydrazine or tyramine were 30.7, 26.0 and 16.3 min., respectively. Phenylhydrazine treated group and tyramine treated group had effect on inhibition of zona hardening as compared to control group. These results suggest that ovoperoxidase is involved in zona hardening during normal activation of the oocytes by sperm. 3. t50 of control oocytes and ovarian oocytes treated with phenylhydrazine or tyramine for 5, 10 and 15 hr in vitro were 14.0, 26.2 and 32.0 min., 14.5, 26.9 and 30.2 min., and 14.0, 24.3 and 31.2 min., respectively. These results suggest that zona hardening in ovarian oocytes matured for various times in vitro cannot be inhibited by peroxidase inhibitors and tyrosine analogue, that the spontaneous zona hardening incultured ovarian oocytes is not caused by the secretory products of cortical granules released during the cortical reaction, ovoperoxidase.

• Development and Reproduction
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• v.9 no.2
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• pp.123-134
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• 2005

Germ cell development during oogenesis, ovarian maturation and first sexual maturity in female Ruditapes philippinarum were investigated by cytological and histological observations. R. philippinarum is dioecious. During vitellogenesis, the Golgi complex, glycogen particles, and mitochondria were involved in the formation of lipid droplets and lipid granules in the cytoplasm of the early vitellogenic oocyte. In the late vitellogenic oocyte, cortical granules, the endoplasmic reticulum, and mitochondria were involved in the formation of proteid yolk granules in the cytoplasm. At this time, exogenous lipid granular substance and glycogen particles in the germinal epithelium passed into the oocyte through the microvilli of the vitelline envelope. The spawning period was once a year between early June and early October, and the main spawning occurred between July and August when seawater temperature was approximately $20^{\circ}C$. The reproductive cycle of this species can be categorized into five successive stages: early active stage(January to March), late active stage(Februaryto May), ripe stage(April to August), partially spawned stage(May to October), and spent/inactive stage (August to February). Percentages of female clams at first sexual maturity of $15.1{\sim}20.0mm$ in shell length were 52.6%(50% of the rate of group maturity was 17.83mm in length), and 100% for the clams >25.1mm.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.2
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• pp.225-243
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• 1991

In recent years immediate implantation has been tried by a few clinicians. This study placed IMZ implants in the rabbit femur with and without bony defects around the implant for simulating fresh extraction site. And one group with bony defects used porous hydroxyapatite ganules(HA) to fill if and the other group left the bony defects around the implant. The purpose of this study was to compare the shear bond strength and the bony contact and formation around the implant. Fifteen rabbits were divided into three groups and placed 10 IMZ implants to each group. Implant sites were surgically prepared with IMZ drills kit and implants were placed(Control), artificial bony defect was created with Apaceram drills kit around the implant sites and implants were placed(Experimental I), bony defect was filled with porous hydroxyapatite granules(Experimental II). Thereafter, rabbits were sacrificed at 8th week and specimens were prepared and pushout tested for shear bond strength of bone-implant interface immediately. Undecalcified and decalcified specimens were prepared with Vilanueva and hematoxylin-eosin stain for light microscopic finding. The results of this study were as follows. 1. In the control group, mean shear strength of bone-implant interface was $2.614{\pm}0.680$ MPa, experimental I was $0.664{\pm}0.322$ MPa, and experimental II was $2.281{\pm}0.606$ MPa. There was significant difference between control and experimental I, between experimental I and experimental II, but did not show significant difference between control and experimental II statistically. 2. In the bony formation surrounding IMZ implant of the three groups, that of cortical bone is more advanced than cancellous bone area. 3. In the histological findings of undecalcified specimens, control and experimental II showed more than 50% of bony or osteoid formation at the bony-implant interface. 4. In the histological findings of undecalcified specimens, experimental I showed less than 50% of bony or osteoid formation at the interface, and observed partial bony defect in the coronal zone. 5. In the experimental II group, were observed direct bony contact to hydroxyapatite granules, and infiltration of a few giant cells. 6. No inflammatory responses were seen around the titanium implants and the hydroxyapatite granules.