• Reproductive and Developmental Biology
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• v.29 no.4
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• pp.235-239
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• 2005

This study was conducted to test whether the transgenic cattle pass the transgene to their progeny through germ cells, and whether the transgene is expressed in the mammary gland of ransgenic cows. Two male ransgenic calves were born from IVF-derived embryos injected with bovine $\beta-casein/human$ lactoferrin fusion gene and then grew up to be reproducible. Semen was collected from a transgenic bull after 18 mon of age and then frozen. Bovine oocytes matured in vitro were fertilized with spermatozoa of the transgenic bull and cultured in $50\;{\mu}L$ drops of CRlaa medium supplemented with 3 mg/mL BSA. After 48 h of culture, cleaved embryos were determined for the presence of transgenes by DNA polymerase chain reaction (PCR). Proportion of transgene positives among bovine embryos fertilized with sperm of the transgenic bull was $20.9\%$ (28/134). One of transgenic bulls did not produce transgenic sperm. Out of 34 calves produced from recipient heifers inseminated with semen of the other bull, 3 $(8.8\%)$ were transgenic animals (2 females and 1 male). Thus, one transgenic bull showed a low transmission frequency below Mendelian levels in both the IVF-derived embryos and his progeny. It was demonstrated by Southern blot that copy numbers of the transgene in the transgenic progeny enhanced about 1.8 times as compared to those of the founder bull The results demonstrate that the transgenic bull carrying human lactoferrin gene could pass his transgene to the progeny through germ cells, although he is a germ-line mosaic.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.85-85
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• 2003

Human lactoferrin (hLF) is an 80 kDa iron-binding glycoprotein that is expressed in high concentration in milk and in lesser amount in the secondary or specific granules of neutrophils and in plasma, LF is classically considered to be related to the binding, transport, and storage of iron. The transgenic mice carrying the human hLF gene in conjunction with the bovine $\beta$-casein promoter produced the human hLF in their milk during lactation. To screen transgenic mice, PCR was carried out using chromosomal DNA extracted from tail or toe tissues. In this study, stability of germ line transmission and expression of hLF were monitored up to generation Fl7 of a transgenic line. When female mouse of generation F9 was crossbred with normal male, generation F9 to Fl7 mice showed similar transmission rates ($66.0 \pm 12.57%, 42.0 \pm 14.98%, 72.2 \pm 25.45%, 50.0 \pm 16.70%, 65.7 \pm 6.45%, 48.6 \pm 14.65%, 54 1 \pm 18 11%, 57.8 \pm 16.16% and 48.6 \pm 20.66$, respectively), implying that the hLF gene can be transmitted stably up to long term generation in the transgenic mice For ELISA analysis, hLF expression levels were determined with an hLF ELISA kit in accordance with the supplier's protocol. Expression levels of human hLF from milk of generation F9 to Fl3 mice were $ 3.2 \pm 0.69 mg/ml, 3.1 \pm 0.81 mg/ml, 4.6 \pm 1.38 mg/ml, 3.1 \pm 0.42 mg/ml, and 4.5 \pm 1,48 mg/ml$, respectively. These expression levels were lower than that of founder (6.6 mg/$m\ell$) mouse. We concluded that transgenic mice faithfully passed the transgene on their progeny and successively secreted target proteins into their milk through several generations.

• Journal of Ginseng Research
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• v.16 no.1
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• pp.31-36
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• 1992

The ultrastructural changes and differentiation mechanism of chromoplasts and leucoplasts from Proplastids in root tip cells of Panax ginseng seedlings were studied with transmission electron microscope. Initial cells have so many proplastids with a few osmiophilic droplets and a lot of mitochon dria at early stage of germination, therefore electron density of cytoplasm is generally higher than that of the other cells just like periblem, plerome and root cap. Proplastids are observed in the initial cells, but only leucoplasts appeared in the central root cap cells. Because root cap cells are derived ultimately from initial cells, the cell organelles in the root cap cells are directly related by those of initial cells. This result postulates that leucoplast is diferentiated from proplastid, and this is the same with other's concepts. On the contrary, the precise observations of chromoplast with crystalline inclusions in the peripheral root cap cells can conclude the direct pathway of chromoplast development from proplastid. Because of the differences of these result from those of other experiments, new scheme of plastid development, direct differentiation of chromoplast from proplastid, can be postulated. And this is the originality of this research on the differentiation of plastids.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.747-752
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• 2013

Oncostatin M (OSM) is a multifunctional cellular regulator acting on a wide variety of cells, which has potential roles in the regulation of gene activation, cell survival, proliferation and differentiation. Previous studies have shown that OSM can induce morphological and/or functional differentiation and maturation of many tumor cells. However, the action of OSM on the induction of differentiation of human hepatocellular carcinoma (HCC) has not been reported. Here, we investigated the effects of different concentrations of OSM on human HCC cell line SMMC-7721 growth, proliferation, cell cycling, apoptosis and differentiation in vitro. Cell growth was determined via MTT assay, proliferation by cell cycle analysis, apoptosis by flow cytometry, morphology by transmission electronic microscopy, and cell function by detection of biochemical markers. Our results demonstrated that OSM strongly inhibited the growth of SMMC-7721 cells in a dose-dependent manner, associated with decreased clonogenicity. Cell cycle analysis revealed a decreased proportion of cells in S phase, with arrest at G0/G1. The apotosis rate was increased after OSM treatment compared to the control. These changes were associated with striking changes in cellular morphology, toward a more mature hepatic phenotype, accompanied by significant reduction of the expression of AFP and specific activity of ${\gamma}$-GT, with remarkable increase in secretion of albumin and ALP activity. Taken together, our findings indicate that OSM could induce the differentiation and reduce cell viability of SMMC-7721 cells, suggesting that differentiation therapy with OSM offers the opportunity for therapeutic intervention in HCC.

• The Korean Journal of Zoology
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• v.38 no.3
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• pp.313-323
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• 1995

Ultrastructural characteristics of hemocytic differentiation pathway in Sericinus montetla Grey were observed with transmission electron microscope. Hemocytic differentiation took place in loose islets of hemopoietic organs as indicated by the presence of differentiating hemocytes; prohemocytes, plasmatocytes, granular cells and spherule cells. They are differentiatied from the stem cells through individual cell lineages. However, differentiating aspects of the oenocytoids were not observed. According to Brehelin and Zachary (1986), the premature hemocytes around the hemopoietic organs were classified into five types; prohemocytes, plasmatocytes, granular cells, spherule cells and oenocytoids.

• 한국전자현미경학회:학술대회논문집
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• 2005.11a
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• pp.144-146
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• 2005

• Journal of Communications and Networks
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• v.7 no.4
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• pp.462-470
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• 2005

We propose a multi-rate and multi-BEP transmission scheme using adaptive overlapping pulse-position modulator (OPPM) and optical power controller in optical code division multiple access (CDMA) networks. The proposed system achieves the multi-rate and multi-BEP transmission by accommodating users with different values of OPPM parameter and transmitted power in the same network. The proposed scheme has advantages that the system is not required to change the code length and number of weight depending on the required bit rate of a user and the difference of bit rates does not have so much effect on the bit error probabilities (BEPs). Moreover, the difference of transmitted powers does not cause the change of bit rate. We analyze the BEPs of the four multimedia service classes corresponding to the com­binations of high/low-rates and low/high-BEPs and show that the proposed scheme can easily achieve distinct differentiation of the service classes with the simple system configuration.

• Journal of Internet Computing and Services
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• v.7 no.1
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• pp.151-164
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• 2006

The DCF of IEEE 802.11 standard coordinates transmissions onto the shared communication channel based on CSMA/CA protocol. Currently, 802,11 is the most widely deployed wireless LAN standard. In this paper, for 802.11-based wireless LAN we propose a service differentiation scheme adopting different contention window sizes and retransmission schemes for two different types of data packets and we present a Markov model for the state of a given station under a finite load traffic condition. We then derive an algorithm to find the transmission probability and the throughput. The proposed model is validated through simulation under various system settings.

• Korean Journal of Animal Reproduction
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• v.21 no.3
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• pp.311-319
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• 1997

This study was carried out to investigate the ultrastructural changes of spermatozoa obtained from 20 of 3-year-old male chum salmon(Oncorhynchus keta) collected and analysed in middle October in 1995. The ultrastructural changes of gonad of fingerlings were examined to describe the sex differentiation of this species. The results obtained in this study were as follows : In spermatozoa, the nucleus is dense and homogeneous. Two spheroidal mitochondria(about 350nm long) are situated in parallel between the nucleus and the axoneme. Spermatozoa mitochondria are assembled into an organized sheath surrounding the outer dense fibres and axoneme of the flagellar midpiece. The sheath flagellum is situated beneath the base of the sperm head. The primordial germ cells of 6.8~7.2${\mu}{\textrm}{m}$ in size, which were buried under fibrous mesenchymal tissue between gut duct and notochord of larva with a total length of 2.4cm at 50 days after hatching. In juvenile of 10.5cm in total length at 70 days after hatching, the gonad was occupied by bundles of oogonia. The dense drumstick bodies(large arrows) are observed in the nuclei of the primordial gonad and surrounding tissue cells of fingerling at 70 days after hatching. The oval Barr bodies(asterisk) are observed in the nuclei of the primordial germ cells under the mitosis(2n). Note the large mitochondria, ribosomes and rough endoplasmic reticulum in the cytoplasm. Accordingly, the fingerlings at 70 days after hatching are identified as the female(xx). In result, the gonadal sex differentiation begins from the 70 days after hatching in chum salmon.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.1-18
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• 2006

A novel transmission electron microscopy technique for the visualization of polymers adsorbed on secondary fines has been developed. This technique has been utilized in observing the adsorption behavior of various wet-end additives. The technique is sensitive enough not only to allow differentiation between linear and branched polymers, but also to observe differences in the adsorption behavior and conformational characteristics of particular polymeric derivatives. Conformational changes of a cationic polyacrylamide (CPAM) were examined in response to variations in wet-end conditions, such as mixing time and system conductivity. The molecular conformations of cationic starch and cationic guar gum were also examined by this technique. The technique has been employed to observe the effects of silica microparticles on the conformational characteristics of CPAM (drainage/retention aid) pre-adsorbed on secondary fines. The transmission electron microscopy method is a viable tool for investigating the macromolecular events that make up a large part of wet end chemistry in papermaking.