• The Korean Journal of Physiology and Pharmacology
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• 제18권2호
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• pp.135-141
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• 2014

The downregulation of A-type $K^+$ channels ($I_A$ channels) accompanying enhanced somatic excitability can mediate epileptogenic conditions in mammalian central nervous system. As $I_A$ channels are dominantly targeted by dendritic and postsynaptic processings during synaptic plasticity, it is presumable that they may act as cellular linkers between synaptic responses and somatic processings under various excitable conditions. In the present study, we electrophysiologically tested if the downregulation of somatic $I_A$ channels was sensitive to synaptic activities in young hippocampal neurons. In primarily cultured hippocampal neurons (DIV 6~9), the peak of $I_A$ recorded by a whole-cell patch was significantly reduced by high KCl or exogenous glutamate treatment to enhance synaptic activities. However, the pretreatment of MK801 to block synaptic NMDA receptors abolished the glutamate-induced reduction of the $I_A$ peak, indicating the necessity of synaptic activation for the reduction of somatic $I_A$. This was again confirmed by glycine treatment, showing a significant reduction of the somatic $I_A$ peak. Additionally, the gating property of $I_A$ channels was also sensitive to the activation of synaptic NMDA receptors, showing the hyperpolarizing shift in inactivation kinetics. These results suggest that synaptic LTP possibly potentiates somatic excitability via downregulating $I_A$ channels in expression and gating kinetics. The consequential changes of somatic excitability following the activity-dependent modulation of synaptic responses may be a series of processings for neuronal functions to determine outputs in memory mechanisms or pathogenic conditions.

• 한국자원식물학회지
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• 제26권4호
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• pp.511-515
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• 2013

멜론으로부터 체세포배를 얻기 위하여 유식물체의 배축 절편을 1 mg/L 2,4-D와 0.5 mg/L BA가 혼합첨가된 MS배지 치상하여 6주 동안 배양하였다. 배축절편으로부터 연한 노란색의 부드러운 캘러스 형성을 거쳐 형성된 체세포배중에는 2개의 자엽을 갖는 정상적인 형태의 체세포배(26%)와 합생 자엽을 갖는 나팔형의 비 정상적인 체세포배(74%)가 관찰되었다. 정상 체세포배의 하배축 부위에서는 원형의 전형성층 조직이 발달되었고, 자엽 절 부위로 이동되면서 점차 독립적으로 나뉘어져 자엽에서는 완전히 2개의 전형성층 조직으로 분화하였다. 그러나 합생 자엽을 갖는 나팔형의 체세포배에서는 하배축에서 발달된 원형의 전형층조직이 자엽 절과 자엽부위에서도 원형의 전형성층 조직으로 연결되어 있었다. 또한 2개의 자엽을 갖는 정상 및 합생 자엽을 갖는 비 정상 체세포배 tunica-corpus구조를 볼 수 없었으며 전형적인 dome구조도 관찰할 수 없었다. 이러한 결과는 체세포배에서 전형성층 조직의 분화는 자엽형성 및 유경조직 형성과 밀접한 관계가 있는 것으로 추측할 수 있다.

• BMB Reports
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• 제39권5호
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• pp.586-594
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• 2006

Germinal centers (GCs) have been identified as site at which the somatic mutation of immunoglobulins occurs. However, somatic mutations in immunoglobulins have also been observed in animals that normally do not harbor germinal centers. This clearly indicates that somatic mutations can occur in the absence of germinal centers. We therefore attempted to determine whether or not GCs exist in TNFR1-deficient mice, and are essential for the somatic mutation of immunoglobulins, using (4-hydroxy-3-nitropheny)acetyl-ovalbumin (NP-OVA). Both wild-type and TNFR1-deficient mice were immunized with NPOVA, and then examined with regard to the existence of GCs. No typical B-cell follicles were detected in the TNFR1-deficient mice. Cell proliferation was detected throughout all splenic tissue types, and no in vivo immune-complex retention was observed in the TNFR1-deficient mice. All of these data strongly suggest that no GCs were formed in the TNFR1-deficient mice. Although TNFR1-deficient mice are unable to form GCs, serological analyses indicated that affinity maturation had been achieved in both the wild-type and TNFR1-deficient mice. We therefore isolated and sequenced several DNA clones from wild-type and the TNFR1-deficient mice. Eight out of 12 wild-type clones, and 11 out of 14 clones of the TNFR-1-deficient mice contained mutations at the CDR1 site. Thus, the wild-type and TNFR1-deficient mice were not extremely different with regard to types and rates of somatic mutation. Also, high-affinity antibodies were detected in both types of mice. Collectively, our data appear to show that affinity maturation may occur in TNFR1-deficient mice, which completely lack GCs.

• 복식문화연구
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• 제29권6호
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• pp.904-921
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• 2021

The aim of this study was to develop a body type suitable for adult men aged from their 20s to their 40s and to present a method of drafting related patterns. To this end, the somatic surface pattern data from previous studies were used. The research method involved drafting torso patterns for each type by setting and distributing the ease to the somatic surface pattern. Appearance evaluation was performed with virtual clothing. Then, the torso pattern for each body type was completed and presented as a draft method. SPSS was used for data analysis in this study. The research results are as follows. Types 1, 2, and 3 were set to 7%, 6%, 5%; 7%, 6%, 4%; and 6.5%, 7%, and 6% for chest, waist, and hip circumference measurements, respectively. The ratio of front to back was 50%:50%, 50%:50%, and 50%:50% of the spare for each body part for Type 1; 70%:30%, 50%:50%, and 60%:40% for Type 2, and 60%:40%, 70%:30%, and 60%:40% for Type 3. A tight-fit torso pattern for each body type suitable for adult males in their 20s to 40s was drafted, which was modified and supplemented through the evaluation of the first and second virtual wear. Considering the practicality of this approach, for generalization of the patterns, the items of the pattern were converted into a drafting method and presented as a draft method.

• Journal of Plant Biotechnology
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• 제3권2호
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• pp.101-106
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• 2001

In order to establish efficient plant regeneration from embryogenic suspension cultures of soybean, Glycine max L, we examined the effects of auxin type and concentration, cytokinin type and concentration, and amino acid type and concentration on the growth of embryogenic clumps from induced callus, and the effect of desiccation of mature somatic embryos obtained from these clumps on the frequency of somatic embryo germination. Embryogenic callus was induced from the edge of the cotyledons cultured on MS medium containing 6% sucrose, 40 mg/L 2,4-D, 0.2% gelrite and pH 5.7. The growth of embryogenic clumps was best in early staged, embryogenic callus that was placed in suspension culture of MS medium containing 5 mg/L 2,4-D and 0.5 mg/L asparagine. Single somatic embryos were isolated from the clumps and plated on the same medium for maturation. When the mature single somatic embryos were desiccated for 96 h, somatic embryo germination came up to approximately 90%. The plantlets germinated after embryos desiccation for 2 weeks were transfered to MS medium containing 3% sucrose,0.2% gelrite and pH 5.7.

• Animal cells and systems
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• 제5권1호
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• pp.71-75
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• 2001

Spin is an abundant maternal transcript comprising up to 0.2% of the total mRNA stock in mouse oocyte, whose protein product is associated with the meiotic spindle. We have identified a new isoform of Spin transcript containing a distinct 5'-untranslated region and the N-terminus of encoded protein. Northern blot and RT-PCR analysis showed that the new isoform is expressed in embryos and most of adult tissues, while the previously identified transcript is expressed solely in mouse oocyte. We thus designated these two Spin isoforms as somatic type and oocyte type, respectively. To investigate the underlying mechanism for the differential expression, genomic structure of Spin was examined. Spin exists as multiple copies in the genome, some of which appears to be pseudogenes, and characterization of Spin genomic clones indicates that oocyte- and somatic-isoforms were generated by alternative splicing. The complex organization of Spin genomic locus and its multifaceted control of expression provide a good model to study the molecular mechanisms of elaborate genome usage in mammals.

• 한국자원식물학회지
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• 제10권4호
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• pp.292-299
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• 1997

국내에 분포하는 개미취속 및 근연 분류군 17종류에 대하여 다양한 분류형질중 체세포염색체수를 조사하여 분류군에 대한 정확한 학명과 분류학적 위치를 파악하고자 하였다. 본 연구에서 취급된 분류군들의 체세포 염색체수는 동일 분류군내에서 개체간의 변이없이 일정하였고 분류군간에는 다양하게 나타났으며, 기본수에 의하여 x=9와 x=8의 2가지 유형으로 구분되었고 x=9인 유형은 배수성에 의하여 세분되었다. 본 연구에서 단양쑥부쟁이와 제주쑥부쟁이, 눈갯쑥부쟁이의 체세포 염색체수가 처음으로 밝혀졌으며, 국내에서 버드쟁이나물로 동정되어 왔던 개체들은 체세포 염색체수와 잎 형태를 조사한 결과, 가새쑥부쟁이의 변이체로 보는 것이 타당하고 사료된다.

• 식물조직배양학회지
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• 제22권1호
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• pp.1-5
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• 1995

벼의 인공종자를 무균상에서 건조시킴으로써 건조형 인공종자를 제조하였다. 1/2 MS배지에서 80%의 수분 손실률을 가진 인공종자는 20%가 발아하였다. 0.1 mg/L ABA가 첨가된 알긴산용액으로 제조한 인공종자는 0-90%의 수분손실률에서 최고 1.7배까지 발아율이 향상되었다. 이러한 결과는 ABA가 인공종자의 제조 및 건조과정에서 물리적 혹은 생리적인 저해에 대한 보호기능을 나타낸 것으로 사료된다.

• 식물조직배양학회지
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• 제21권1호
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• pp.7-14
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• 1994

국내 5가지 품종의 대두 미숙배로부터 발생되는 체세포배 형성빈도와 자엽변이에 대한 2,4-D 농도의 영향을 알아보였다. 여러가지 농도의 2,4-D가 첨가된 MS 기달배지에 각 품종의 미숙배를 6주동안 암소에서 배양한 결과 '울산콩', '금산콩', '뱀콩' 및 '반청두'의 경우 1-2 mg/L 2,4-D를 첨가한 배지에서, '아주까리'는 20 mg/L 2,4-D를 첨가한 배지에서 가장 높은 체세포배 형성빈도를 보였다. 또한 횡으로 반분한 체세포배를 0.1-1 mg/L 2,4-D가 첨가된 배지에서 배양하였을 때 최고 70%의 빈도로 이차배를 형성하였다. 미숙배(접합자배)에서 유도된 체세포배의 형태는 2,4-D 농도에 따라 다르게 나타났는데 즉, 0.2 mg/L 이하의 농도에서는 하나의 자엽을 갖는 배와 나팔형보다는 두개의 자엽을 갖는 정상적인 형태가, 0.5-4 mgh 농도에서는 정상적인 형태보다는 나팔형의 체세포배 형성빈도가 높게 나타났다. 또한 체세포배의 자엽형태에 따라 식물체 재생률을 조사하기 위하여 ME 기본배지와 0.1 mg/L IAA, 1 mg/L BA, 1mg/L Gh₃ 및 0.5% 활성탄을 각각 U 기본배지에 첨가하여 16시간 광주기하에서 4주동안 배양한 결과, 식물체 재생률은 일반적으로 두개의 자엽을 갖는 정상적인 배가 하나의 자엽을 갖는 배, 나팔형 및 구형기의 체세포배에 비하여 높았으며, 특히 1 mg/L GA3를 첨가한 배지에서 가장 높은 재생률(25%)을 보였다.

• 한국연초학회지
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• 제15권2호
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• pp.123-129
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• 1993

Mesophyll protoplasts derived from young leaves of Nicotiana rustica and N. tabacum cv Burley 21 were fused with the aid of polyethylene glycol(PEG). Cytological examination of protoplasts after PEG treatment revealed 12.8 % heterokaryocytes. After 7 weeks culture, the hybrid calli showing greenish white with a compact appearance were selected in contrast to parental type calli tinged with white or green color. The somatic hybrid plants were verified by morphological, biochemical and cyclological analysis. A heterosis effect for plant vigor and height was observed but the shape of leaves and flower characteristics were intermediate between N. tabacum and N. rutstica. The isozyme banding patterns for peroxidase of somatic hybrid lines were compared with the parent species. A number of isozyme bands derived from both parental species were found in the hybrids. Somatic hybrid plants have been successfully backcrossed to the parental N. tabacum particularly with somatic hybrid plants as female parents. These hybrid plants yielded small seeds, only few which were germinable.