• Clinical and Experimental Reproductive Medicine
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• v.27 no.1
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• pp.39-46
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• 2000

Objective: A number of studies to improve in vitro culture conditions have been tried over past ten years by using co-culture system with helper somatic cells. However, the mechanism of coculture is poorly understood. This study was designed to understand the mechanism for the mode of actual action of co-culture using co-culture system of ICR strain's 1-cell embryos with human oviduct epithelial cells by examining the effect of conditioned medium and contactless coculture using a cell culture insert on the embryo development and by measuring the level of superoxide anion from conditioned medium after co-culture. Methods: ICR strain's zygote embryos were cultured in medium alone (control), coculture, conditioned medium, or contactless coculture system for 6 days. Conditioned media (CM) were prepared as following 5 groups. All CM were collected after culturing oviduct cells for 2 days. CM-1 was stored at $-20^{\circ}C$ until use, and CM-2 was prepared just before use as a culture medium. CM-3 was cocultured with embryos and retrieved just before use. CM-4 and CM-5 were derives from the microfilteration of CM-2 and CM-3, respectively, using Microcon-10 (10 kDa molecular weight cut-off). The percentage of the embryos developed to hatched blastocyst stage and the level of superoxide anion in supernatant from medium alone culture (control), coculture, and contactless coculture were measured. Results: The rates of embryo development to the hatched blastocyst stage were significantly higher in coculture (43%) than in control (0%) (p<0.05). The CM-1 group had no embryo development since 2-cell embryonic stage, whereas the CM-2, CM-3, CM-4 and CM-5 groups had the improved development to 4 or 8 cell embryo stage, but the similar rate of development to hatched blastocyst compared to control. The effect of coculture on embryo development was disappeared in the contactless coculture group. The level of superoxide anion was significantly reduced in coculture group compared to control. Conclusion: It is concluded that the present coculture system overcomes the 2-cell block in vitro and improves the embryo development. This beneficial effect may be due to the direct cell-cell contact between embryo and helper cells or the removal of deleterious components from medium rather than the embryotrophic factors.

• Reproductive and Developmental Biology
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• v.37 no.2
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• pp.57-64
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• 2013

Developmental potential of cloned embryos is related closely to epigenetic modification of somatic cell genome. The present study was to investigate the effects of applying histone deacetylation inhibitor, trichostatin A (TSA) to activated porcine embryos on subsequent development of porcine parthenogenetic and nuclear transfer embryos. Electrically activated oocytes were treated with 5 nM TSA for different exposure times (0, 1, 2 and 4 hr) and then the activated embryos were cultured for 7 days. The reconstructed embryos were treated with different concentrations of 0, 5, 10 and 25 nM TSA for 1 hr. Also 5 nM TSA was tested with different exposure times of 0, 0.5, 1, 2 and 4 hr. And fetal fibroblast cells were treated with 50 nM TSA for 1, 2 or 4 hr and with 5 nM TSA for 1 hr. Cumulus-free oocytes were enucleated and reconstructed by TSA-treated donor cells and electrically fused and cultured for 6 days. In parthenogenetic activation experiments, 5 nM TSA treatment for 1 hr significantly improved the percentage of blastocyst developmental rates than the other groups. Total cell number of blastocysts in 1 hr group was significantly higher than other groups or control. Similarly, blastocyst developmental rates of porcine NT embryos following 5 nM TSA treatment for 1 hr were highest. And the reconstructed embryos from donor cells treated by 50 nM TSA for 1 hr improved the percentage of blastocyst developmental rates than the control group. In conclusion, TSA treatment could improve the subsequent blastocyst development of porcine parthenogenetic and nuclear transfer embryos.

• Journal of Food Hygiene and Safety
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• v.2 no.3
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• pp.109-119
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• 1987

This Study was conducted to provide fundamental data necessary for the improvement of milk quality. Milk quality was evaluated by 3 methods; milk fat percent measurement, methylene blue reduction test (MBRT), and somatic cell count measurement. At the same time, condition of hygienic management of dairy facilities and cows was investigated in each of 234 dairy farms located in Gyunggi area from May, 1986 to April, 1987. The results were as follows 1. Average milk fat percents among farms were 3.67%, 3.64%, 3.43%, 3.48% in January, April, July and October, respectively. The diUerences of milk fat percent from month to month were statistically significant (p<0.005). and the seasonal average was 3.56%. 2. Numbers of farms which produced bulk milk of first grade by MBRT were 153(65.4%), 157(67.1%), 76(32.5%) and 141(60.2%) in January, April, July and October, respectively. The diUerences among months were statistically significant (p<0.005). Also, significant diUerences of grade by milking quantity (p<0.05), presence of milk cooler (p<0.01), and collection means (p<0.05) were demonstrated. 3. Number8 of farms which produced bulk milk of fir8t grade in somatic cell count measurement were 227(97.0%), 226(96.6%), 218(93.2%) and 223(95.3%) in January, April, July and October, respectively. And diUerences of grade by the pratice of teat dipping, dry cow therapy and manner in which udder washing towel was used statisticaJJy 8ignificant (p<0.01).

• Korean Journal of Veterinary Research
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• v.55 no.4
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• pp.253-257
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• 2015

Oregano (Origanum vulgare) is an aromatic herb belonging to the Lamiaceae family. This study evaluated the therapeutic effect of oregano essential oil (OEO) on clinical bovine mastitis caused by Staphylococcus (S.) aureus and/or Escherichia (E.) coli. Thirty-two quarters from 18 lactating cows with subclinical mastitis were selected from a dairy farm and were divided into 4 groups (8 quarters/group): negative control (CON), positive control (GEN) and two OEO-treated groups (OEO-1 and OEO-2). Each group was intramammarily treated with saline, 10 g/tube of gentamicin ointment, and single and double doses of 0.9 mL OEO ointment twice a day for three days, respectively. After the treatments, physical udder conditions were greatly improved in GEN and OEO groups. In CON group, somatic cell counts (SCCs), number of white blood cells (WBC) and bacteria were increased. However, in OEO groups, SCCs and number of WBC were significantly decreased and S. aureus and E. coli were not detected in milk as compared with those before the treatments as well as GEN group. These results suggest that OEO may be a useful alternative to antibiotics for the control of subclinical bovine mastitis caused by S. aureus and/or E. coli.

• IMMUNE NETWORK
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• v.1 no.2
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• pp.104-108
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• 2001

Aging is a senescence and defined as a normal physiologic and structural alterations in almost all organ systems with age. As Leonard Hayflick, one of the first gerontologists to propose a theory of biologic aging, indicated that a theory of aging or longevity satisfies the changes of above conditions to be universal, progressive, intrinsic and deleterious. Although a number of theories have been proposed, it is now clear that cell aging (cell senescence) is multifactorial. No single mechanism can account for the many varied manifestations of biological aging. Many theories have been proposed in attempt to understand and explain the process of aging. Aging is effected in individual by genetic factors, diet, social conditions, and the occurrence of age-related diseases as diabetes, hypertension, and arthritis. It involves an endogenous molecular program of cellular senescence as well as continuous exposure throughout life to adverse exogenous influences, leading to progressive infringement on the cell's survivability so called wear and tear. So we could say the basic mechanism of aging depends on the irreversible and universal processes at cellular and molecular level. The immediate cause of these changes is probably an interference in the function of cell's macromolecules-DNA, RNA, and cell proteins-and in the flow of information between these macromolecules. The crucial questions, unanswered at present, concerns what causes these changes in truth. Common theories of aging are able to classify as followings for the easy comprehension. 1. Biological, 1) molecular theories - a. error theory, b. programmed aging theory, c. somatic mutation theory, d. transcription theory, e. run-out-of program theory, 2) cellular theories - a. wear and tear theory, b. cross-link theory, c. clinker theory, d. free radical theory, e. waste product theory, 3) system level theory-a. immunologic/autoimmune theory, 4) others - a. telomere theory, b. rate of living theory, c. stress theory, etc. Prevention of aging is theoretically depending on the cause or theory of aging. However no single theory is available and no definite method of delaying the aging process is possible by this moment. The most popular action is anti-oxidant therapy using vitamin E and C, melatonin and DHEA, etc. Another proposal for the reverse of life-span is TCP-17 and IL-16 administration from the mouse bone marrow B cell line study for the immunoglobulin VDJ rearrangement with RAG-1 and RAG-2. Recently conclusional suggestion for the extending of maximum life-span thought to be the calory restriction.

• Korean Journal of Plant Tissue Culture
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• v.25 no.1
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• pp.13-19
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• 1998

We have reported previously that intact embryogenic cells can be used instead of protoplasts for electroporation-mediated transformation of zoysiagrass and rice. In this study, conditions of the tissue electroporation were examined to optimize the procedures. Embryogenic cell suspensions were established in liquid MS medium containing 2 mg/L of 2,4-D with embryogenic calluses induced from mature embryos of Z. japonica. The suspension-cultured cell clumps were electroporated with 35S-gusA expression vector DNA, and degrees of DNA introduction into the cells were determined by histological expression rates of the gusA marker gene. DNA transfer into the cell clumps occurred in wide range of voltage (100-400 V) and capacitance (10-1980 $\mu\textrm{F}$), but more in the ranges of 200-300 V and 330-800 $\mu\textrm{F}$ DNA concentrations higher than 6 $\mu\textrm{g}$/mL were adequate for GUS expression of the electroporated cells. DNA transfers were confirmed in all three embryogenic cell lines but only in one out of eleven non-embryogenic lines. Positive GUS expressions occurred with DNAs added even 20-40 h after pulse treatments. As a promoter of gusA, Act1 and Ubi1 were effective 7 and 5 times than 35S respectively in number of GUS expression units on electroporated cell clumps. Embryogenic cell clumps survived and regenerated into plantlets after pulse treatments of wide range of conditions.

• Reproductive and Developmental Biology
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• v.30 no.2
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• pp.119-124
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• 2006

The present study compared the developmental potential of cloned porcine embryos with mesenchymal stem cells (MSCs), fetal fibroblasts (FFs) and cumulus cells (CCs) by assessing the cleavage and blastocyst rate, total cell number, inner cell mass (ICM) ratio and apoptosis. MSCs were isolated by ficoll gradients from femur of -6 month old female pig, and maintained for primary cultures. FFs from a female fetus at ${\sim}30$ day of gestation were established, and CCs were obtained from cumulus oocyte complexes (COCs) aspirated from $3{\sim}6$ mm follicles in diameter. Donor cells at $3{\sim}4$ passage were employed for nuclear transfer (NT). COCs were matured and fertilized in vitro(IVF) as control. Cleavage rate was significantly (P<0.05) higher in IVF than in NT embryos with MSCs, FFs and CCs ($82.7{\pm}8.9%\;vs\;70.6{\pm}5.4,\;68.7{\pm}5.1\;and\;63.4{\pm}5.6%$, respectively). However, blastocyst rates in IVF and NT embryos derived from MSCs ($24.5{\pm}2.8\;and\;20.4{\pm}8.3%$) did not differ, but were significantly (P<0.05) higher than NT derived from FFs and CCs ($10.6{\pm}2.7\;and\;9.8{\pm}2.1%$). Total cell number and the ratio of ICM to total cells among blastocysts cloned from MSCs ($35.4{\pm}5.2\;and\;0.40{\pm}0.09%$, respectively) were significantly (P<0.05) higher than those from FFs and CCs ($24.9{\pm}6.2%\;vs\;0.19{\pm}0.16,\;23.6{\pm}5.5\;and\;0.17{\pm}0.16%$, respectively). Proportions of TUNEL positive cells in NT embryos from FFs and CCs ($6.9{\pm}1.5\;and\;7.4{\pm}1.7%$, respectively) were significantly (P<0.05) higher than in MSCs ($4.8{\pm}1.4%$) and IVF ($2.3{\pm}0.9%$). The results demonstrate that MSCs have a greater potential as donor cells than FFs and CCs in achieving enhanced production of cloned porcine embryos.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.1
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• pp.44-50
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• 1996

Sex differentiation in the rockfish, Sebastes schlegeli, was studied by using a histological method for the appearance of primordial germ cell, formation of primitive gonad and differentiation of female and male. The primordial germ cells were buried under fibrous mesenchymal tissue between gut and mesonephric duct of pre-larva with a total length (TL) of 6.3 mm at 2 days after parturition. In juvenile of TL $5.2\~5.9cm$ at 65 days after parturition, the gonad composed of a large number of genial cell and formed of cavity along the lateral side of the gonad, differentiated to the ovary. At this time, the gonad formed seminiferous tubules by somatic cells, differentiated to the testis. In juvenile of TL $7.0\~7.2cm$ cm at 115 days after parturition, gonads divided into testis contained pigment cell and ovary absent pigment cell. S. schlegeli differentiated directly into male or female without an intermediate female phase at early indifferentiated stage. Therefore, S. schlegeli belongs to the differentiated type of gonochoristic teleosts. At 350 days after parturition, sex ratio was approximately 1 : 1(p>0.05).

• Journal of Korean Society of Forest Science
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• v.17 no.1
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• pp.1-15
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• 1973

In an effort to improve the major tree species in Korea, the seed of Robinia pseudoacacia, Pinus rigida, Pinus densiflora, Pinus thunbergii and Larix leptolepis were treated with X-ray and thermal neutron at the Brookhaven National Laboratory, and germination rate of the seed and some characteristics of the seedlings from irradiated seed were investigated and the results were summarized as follows. 1. The germination rate of the irradiated seed of Robinia pseudoacacia, Pinus densiflora, Pinus thunbergii and Pinus rigida was decreased, when the irradiation time of thermal neutron increased from 3 hours to 9 hours. The seed of Larix leptolepis was completely died out in all range of irradiation time. 2. The seed of Pinus densiflora, Robinia pseudoacacia and Pinus rigida showed low germination rate, when the dosage of radiation increased in the range of 10,000r-30,000r X-ray. This dosage of radiation was almost lethal to the seed of Pinus thunbergii and Larix leptolepis. 3. The growth rate of radiated Robinia pseudoacacia has been decreased when the dosage of X-ray and thermal neutron increased. However, the trees treated with thermal neutron for 3 hours showed 14.9 percent-increase in seedling height and some thornless individuals appeared in this treatment. 4. Individuals with variegated leaf, rugose leaf and albino were appeared in X-ray and thermal neutron treatment. 5. Abnormal mitosis of somatic cell, cell with two nucleoli, cell with two nuclei and chromosome clump in mitosis of somatic cell were observed in Robinia pseudoacacia irradiated with thermal neutron. 6. Resistanty against pawdery mildew was decreased in Robinia pseudoacacia radiated with X-ray and thermal neutron. 7. Length of stomata did not show any difference however number of stomata per unit area decreased in Robinia pseudoacacia radiated with thermal neutron. The leaves of Robinia pseudoacacia radiated with thermal neutron were thicker than those of non-treated one, but width of palisade tissue was decreased. The most sensitive one among those species to the thermal neutron treatment was Larix leptolepis, followed by Pinus densiflora, Robinia pseudoacacia, Pinus thunbergii and Pinus rigida in the order. In X-ray treatment, the most sensitive one was Larix leptolepis, followed by Pinus densiflora, Pinus thunbergii, Pinus rigida and Robinia pseudoacacia in the order. Morphological, cytological variation of the radiated Robinia pseudoacacia seemed to indicate some possibility to be used for tree improvement.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.6
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• pp.485-495
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• 1991

This experiment was carried out to obtain the information on the crossability, variation of chromosome number in pollen mother cell (PMC) and somatic cell of the progeny from the cross between hexaploid triticale cv. Sinkihomil and two diploid rye varieties. Seed set was 39.3 to 41.6% (averaged 40.5%) in the cross between triticale (P$_1$) and rye(P$_2$), which resulted in 0.33% in F$_2$(selfed F$_1$), 2.69% in F$_1$/P$_1$ 5.47% in F$_1$/P$_2$ respectively. However, seed set was extremely low in both reciprocal crosses when triticale was used as male. Germination rate of the crossed seed was 94.0% in F$_1$ 40.8% in F$_2$(selfed F$_1$), 59.5% in F$_1$/P$_1$ and 65.9% in F$_1$/P$_2$ from the cross between triticale and rye, respectively. Pollen fertility of F$_1$ plant was averaged 18.7% in the cross between triticale and rye. Number of Uni-, Bi-, and Trivalent in PMC was 12. 6, 6.94, and 0.53, respectively, in the F$_1$ between the triticale and rye. There were 28 chromosomes in F$_1$, 21 to 34 in F$_2$, 34 to 38 in F$_1$/P$_1$ and 19 to 23 in F$_1$/P$_2$ from the cross between the triticale and rye, respectively.