• 제목/요약/키워드: biology major

검색결과 2,042건 처리시간 0.036초

서양등골나물 휘발성 추출물의 알레로파시 효과 (Allelopathic Effect of Volatile Extracts from Eupatorium rugosum)

  • 길지현;심규철;이호준
    • The Korean Journal of Ecology
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    • 제28권3호
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    • pp.135-139
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    • 2005
  • 서양등골나물의 휘발성 추출물에 포함된 terpenoid 화합물을 분리, 동정하였고, 주요 물질 4종에 대한 종자발아와 유식물 생장을 조사하였다. 서양등골나물 정유에 포함된 화합물의 수는 $\beta$-caryophyllene, $\alpha$-terpinenol, chamazulene, bornyl acetate, $\alpha$-pinene등 총 49종이었으며, 그 중 3종은 미확인되었다. 서양등골나물의 정유로부터 분리 확인한 휘발성 화학물질 중 다량 함유되어 있거나 중요한 성분으로 판명된 $\alpha$-pinene, bornyl acetate, linalool 및 terpinen-4-ol 등 4종의 물질에 대한 녹두의 발아 억제 효과를 조사하였다. linalool과 terpinen-4-ol에 의해서는 녹두의 종자가 전혀 발아하지 못하여 발아 억제효과가 매우 큰 것으로 보인다. 정유 내 화합물에 의한 녹두 유식물의 초기 생장 결과, $\alpha$-pinene과 bornyl acetate에 대한 묘조와 유근의 생장은 농도에 따라 점점 억제되었고, linalool과 terpinen-4-ol에 대해서는 실험구에서 생장 반응이 나타나지 않을 만큼 강하게 억제반응이 나타났다. 생체량에 있어서 $\alpha$-pinene의 경우 58 ${\mu}l$ 이상에서 유의한 영향을 미치고 있었으며, bornyl acetate의 경우에는 19 ${\mu}l$ 이상에서 감소하는 것으로 나타났으나 그 이후에는 통계적으로 유의한 차이를 나타내지는 않았다. 위의 결과를 종합해 볼 때, 정유 내에 포함된 서양등골나물의 알레로 화합물 중 생물검정에 사용된 $\alpha$-pinene, bornyl acetate, linalool과 terpinen-4-ol은 식물의 발아 억제 효과를 나타내는 주요한 물질 중 하나로 생각되며, 특히 linalool과 terpinen-4-ol은 다른 식물의 생장을 감소시키는 데 탁월한 효과가 있음을 알 수 있었다.

고유종 꼬리말발도리의 생식특성과 동위효소 유전다양성 (Breeding System and Allozyme Genetic Diversity of Deutzia paniculata Nakai, an Endemic Shrub in Korea)

  • 장진성;김휘
    • 한국산림과학회지
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    • 제103권4호
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    • pp.519-527
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    • 2014
  • 고유식물인 꼬리말발도리는 팔공산, 달음산, 가지산과 운문산 등 경상남북도에 제한적으로 분포한다. 본 연구대상인 4개 집단의 크기는 달음산의 최소 100개체에서 운문산 집단이 최대 3,500개체까지이다. 인공수분실험 결과, 생식양식은 완전 타가수분이며, 주요 관찰 화분매개자는 Lasioglossum exiliceps (Vachal)과 호리꽃등에 [Allograpta balteata (de Geer)]였다. 동위효소로 유전적 다양성을 측정한 결과, 종 수준에서의 평균적인 유전다양성은 유전자좌 당 평균 대립유전자수($A_s$)는 1.33, 유전다양성($H_{es}$)은 0.110으로 이미 보고된 고유식물종의 유전다양성과 비슷한 값을 보였다. 달음산 집단은 모든 개체에서 동일한 유전적 조성을 보였으며, 이 집단의 전체 개체가 클론으로 추정된다. 유전자좌의 비율(P)과 유전자좌당 평균 대립유전자($A_P$)의 수는 팔공산 집단이 가장 높았다. 집단 간의 전체 유전 고정지수($F_{IT}$)는 집단 내 지수($F_{IS}$)보다 높아 집단 내 이형접합자의 비율은 높지만, 종 전체 이형접합자 부족현상이 확인되었다. 집단 간의 유전적 분화의 정도를 나타내는 $F_{ST}$값은 0.223, 각 집단 간의 유전적 거리는 평균 0.047(0.011-0.066)로 단형성을 갖는 유전자가 많아 실제 분화는 일부 유전자좌에 국한된 결과이다. 꼬리말발도리의 유전다양성의 감소는 집단의 유효집단 크기 감소와 관련이 있으며, 현지내의 생육지 보전과 함께 현지외 보전을 위해 각 집단별로 최대 유전 다양성을 확보하는 전략이 필요하다.

백서 두개골 실험적 결손부에서 Para-Dioxanone 차단막의 골조직 재생 효과 (THE BONE REGENERATIVE EFFECTS OF PARADIOXANONE ON THE CALVARIAL CRITICAL SIZE DEFECT IN SPRAGUE DAWLEY RATS)

  • 권석훈;석헌주;김종관;정한성;문익상
    • Journal of Periodontal and Implant Science
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    • 제33권1호
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    • pp.61-77
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    • 2003
  • The major goals of periodontal therapy are the functional regeneration of periodontal supporting structures already destructed by periodontal disease as well as the reduction of signs and symptoms of progressive periodontal disease. There have been many efforts to develop materials and therapeutic methods to promote periodontal wound healing. Bone graft & guided tissue are being used for the regeneration of destroyed periodontium these days. Non-resorbable membranes were used for Guided tissue regeneration in early days, however more researches are focused on resorbable membranes these days. The aim of this study is to evaluate the osteogenesis of paradioxanone membrane on the calvarial critical size defect in Sprague Dawley rats. An 8 mm diameter surgical defect was produced with a trephine bur in the area of the midsagittal suture. The rats were divided into three groups: Untreated control group, Biomesh(R) group and paradioxanone group. The animals were sacrificed at 4, 8 and 12 weeks after surgical procedure. The specimens were examined by histologic, histomorphometric analyses. The results are as follows: 1. In histological view on Biomesh(R), no visible signs of resorption was observed at 4 weeks but progressive resorption was observed at 8 weeks through 12 weeks. Paradioxanone membrane expanded at 4 weeks, and rapid resorption was observed at 8 weeks. In both the membranes, inflammatory cells were observed around them. Inflammatory cells decreased with time but were still present at 12 weeks. More inflammatory cells were observed in paradioxanone membranes than in Biomesh(R) membrane. 2. The area of newly formed bone in the defects were 0.001${\pm}$0.001, 0.006${\pm}$0.005, 0.002${\pm}$0.003 at the 4 weeks, 0.021${\pm}$0.020, 0.133${\pm}$0.073, 0.118${\pm}$0.070 at the 8 weeks and 0.163${\pm}$0.067, 0.500${\pm}$0.197, 0.487${\pm}$0.214 at the 12 weeks in the control group, Biomesh(R) group and experimental group respectively. Compared to the control group, Biomesh(R) group displayed significant differences at 4,8, and 12 weeks and the paradioxanone group at 8 and 12 weeks.(P<0.05)

U.S. Forest Service Research : Its Administration and Management

  • Krugman, Stanley L.
    • 한국산림과학회지
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    • 제76권3호
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    • pp.243-248
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    • 1987
  • The U.S. Forest Service administers the world's largest forestry research organization. From its modest beginning in 1876, some 30 years before the United States national forest system was established, the research branch has devoted its effort to meet current and future information needs of the forestry community of the United States, not just for the U.S. Forest Service. The research branch is one of three major administrative units of the U.S. Forest Service. The others being the National Forest System and State and Private Forestry. Currently the National Forest System comprises 155 national forests, 19 national grasslands, and 18 utilization projects located in 44 states. Puerto Rico, and the Virgin Islands. The National Forest System manages these areas for a large array of uses and benefits including timber, water, forage, wildlife, recreation, minerals, and wilderness. It is through the State and Private Forestry branch that the U.S. Forest Service cooperates and coordinates forestry activities and programs with state and local governments, forest industries, and private landowners. These activities include financial and technical assistance in disease, insect, and fire protection ; plan forestry programs ; improve harvesting and marketing practices ; and transfer forestry research results to user groups. Forestry research is carried out through eight regional Forest Experiment Stations and the Forest Product Laboratory. Studies are maintained at 70 administrative sites, and at 115 experimental forest and grasslands. All of the current sciences that composed modern forestry are included in the research program. These range from forest biology (i. e. silviculture, ecology, physiology, and genetics) to the physical, mathematical, engineering, managerial, and social sciences. The levels of research range from application, developmental, and basic research. Research planning and priority identification is an ongoing process with elements of the research program changing to meet short-term critical information needs(i. e. protection research) to long-term opportunities(i. e. biotechnology). Research planning and priority setting is done in cooperation with National Forest Systems, forest industries, universities, and individual groups such as environmental, wilderness, or wildlife organizations. There is an ongoing review process of research administration, organization, and science content to maintain quality of research. In the U.S. Forest Service the research responsibility is not completed until the new information is being applied by the various user group : I. e. technology transfer program. Research planning and development in the U.S. Forest Service is a dynamic activity. Porgrams for the year 2000 and beyond are now in the planning stage.

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황색 끈끈이트랩을 이용한 솔껍질깍지벌레(Homoptera: Margarodidae) 예찰 (Monitoring of Black Pine Bast Scale, Matsucoccus thunbergianae (Homoptera: Margarodidae) Using Yellow Sticky Trap)

  • 이창준;김동수;정영학;이상명;이석준;이동운
    • 한국응용곤충학회지
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    • 제57권3호
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    • pp.143-149
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    • 2018
  • 솔껍질깍지벌레(Matsucoccus thunbergianae)는 우리나라 곰솔(Pinus thunbergiane)림의 주요 해충중의 하나이다. 솔껍질깍지벌레는 단목(丹木)마다 밀도에 차이가 있고, 수관 내 가지별로도 밀도차이가 있어 예찰이 어렵다. 따라서 본 연구는 황색 끈끈이트랩을 이용하여 솔껍질깍지벌레의 분포나 발생을 예찰할 수 있는 방법을 제시하기 위하여 수행되었다. 곰솔림에서 끈끈이 트랩에 유인된 솔껍질깍지벌레 수컷 성충의 밀도와 가지 내 약충의 밀도는 높은 상관관계를 보였다. 끈끈이트랩에 유인된 솔껍질깍지벌레 수컷성충의 밀도는 곰솔의 상층부가 하층부보다 높았으나 통계적 차이는 없었다. 곰솔 가지의 단위면적당 솔껍질깍지벌레 밀도는 흉고직경이 클수록 높아지는 경향을 보였으며 1~2.5 cm 사이의 굵기내에서는 통계적 차이가 없었다. 곰솔 가지의 방향이 지면을 향하는 쪽이 반대 방향을 향하는 쪽에 비하여 솔껍질깍지벌레의 밀도가 높았다. 솔껍질깍지벌레의 예찰에 끈끈이 트랩의 사용을 제안하며, 가지에서의 밀도는 2~2.5 cm 굵기의 가지를 선택하여 지면쪽의 밀도 조사를 추천한다.

수출분재 주요 해충인 알락하늘소와 유리알락하늘소에 대한 포스핀 훈증 효과 검정 (Evaluation of Phosphine Efficacy on Anoplophora chinensis and A. glabripennis in Export Bonsai)

  • 이상명;정영학;이병호;김봉수;박민구;이동운
    • 한국응용곤충학회지
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    • 제57권3호
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    • pp.151-160
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    • 2018
  • 알락하늘소(Anoplophora chinensis)와 유리알락하늘소(A. glabripennis)는 전 세계적으로 검역상 중요한 하늘소과 해충이다. 우리나라에서 이들은 자연 기주목과 분재에서 피해를 주고 있다. 본 연구에서는 분재에서 phosphine의 이들 두 하늘소에 대한 방제효과를 조사하였다. Phosphine은 솔수염하늘소 유충과 알에 대해 높은 훈증효과를 보였다. $2g/m^3$ 농도의 phosphine을 24시간 훈증처리 시 유리알락하늘소와 알락하늘소 난은 부화하지 못하였고, 알락하늘소 유충은 동일농도에 168시간 훈증처리 시 100% 치사되었다. 분재 생육기(2월)나 휴면기(1월) 모두에서 phosphine 훈증제는 $2g/m^3$ 농도에서 두 알락하늘소를 100% 치사시켰다. 그러나 2월에 각 분재목[단풍나무(Acer palmatum)와 소사나무(Carpinus turczaninowii), 아그배나무(Malus sieboldii)]을 대상으로 훈증처리 시, 세 수종 모두에서 잎과 꽃잎의 크기가 작아지고, 꽃의 개화가 지연되는 약해가 발생되었다.

Human $CD103^+$ dendritic cells promote the differentiation of Porphyromonas gingivalis heat shock protein peptide-specific regulatory T cells

  • Kim, Myung-Jin;Jeong, Eui-Kyong;Kwon, Eun-Young;Joo, Ji-Young;Lee, Ju-Youn;Choi, Jeomil
    • Journal of Periodontal and Implant Science
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    • 제44권5호
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    • pp.235-241
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    • 2014
  • Purpose: Regulatory T cells (Tregs), expressing CD4 and CD25 as well as Foxp3, are known to play a pivotal role in immunoregulatory function in autoimmune diseases, cancers, and graft rejection. Dendritic cells (DCs) are considered the major antigen-presenting cells (APCs) for initiating these T-cell immune responses, of which $CD103^+$ DCs are derived from precursor human peripheral blood mononuclear cells (PBMCs). The aim of the present study was to evaluate the capacity of these PBMC-derived $CD103^+$ DCs to promote the differentiation of antigen-specific Tregs. Methods: Monocyte-derived DCs were induced from $CD14^+$ monocytes from the PBMCs of 10 healthy subjects. Once the $CD103^+$ DCs were purified, the cell population was enriched by adding retinoic acid (RA). Peptide numbers 14 and 19 of Porphyromonas gingivalis heat shock protein 60 (HSP60) were synthesized to pulse $CD103^+$ DCs as a tool for presenting the peptide antigens to stimulate $CD3^+$ T cells that were isolated from human PBMC. Exogenous interleukin 2 was added as a coculture supplement. The antigen-specific T-cell lines established were phenotypically identified for their expression of CD4, CD25, or Foxp3. Results: When PBMCs were used as APCs, they demonstrated only a marginal capacity to stimulate peptide-specific Tregs, whereas $CD103^+$ DCs showed a potent antigen presenting capability to promote the peptide-specific Tregs, especially for peptide 14. RA enhanced the conversion of $CD103^+$ DCs, which paralleled the antigen-specific Treg-stimulating effect, though the differences failed to reach statistical significance. Conclusions: We demonstrated that $CD103^+$ DCs can promote antigen-specific Tregs from naive T cells, when used as APCs for an epitope peptide from P. gingivalis HSP60. RA was an effective reagent that induces mature DCs with the typical phenotypic expression of CD103 that demonstrated the functional capability to promote antigen-specific Tregs.

Inhibition of HBV replication and gene expression in vitro and in vivo with a single AAV vector delivering two shRNA molecules

  • Li, Zhi;He, Ming-Liang;Yao, Hong;Dong, Qing-Ming;Chen, Yang-Chao;Chan, Chu-Yan;Zheng, Bo-Jian;Yuen, Kwok-Yung;Peng, Ying;Sun, Qiang;Yang, Xiao;Lin, Marie C.;Sung, Joseph J.Y.;Kung, Hsiang-Fu
    • BMB Reports
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    • 제42권1호
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    • pp.59-64
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    • 2009
  • Hepatitis B virus (HBV) infection is highly prevalent worldwide. The major challenge for current antiviral treatment is the elevated drug resistance that occurs via rapid viral mutagenesis. In this study, we developed AAV vectors to simultaneously deliver two or three shRNAs targeting different HBV-related genes. These vectors showed markedly better antiviral effects than ones that delivered a single shRNA in vitro. A dual shRNA expression vector (AAV-157i/1694i), which simultaneously expressed two shRNAs targeted the S and X genes of HBV, reduced HBsAg, HBeAg and HBV DNA levels by $87{\pm}4$, $80.3{\pm}2.6$ and $86.2{\pm}7%$ respectively, eight days post-transduction. In a mouse model of prophylactic treatment, HBsAg and HBeAg were reduced to undetectable levels and the serum HBV DNA level was reduced by at least 100 fold. These results indicate that AAV-157i/1694i generates potent anti-HBV effects and that the strategy of constructing multi-shRNA expression vectors may lead to enhanced anti-HBV efficacy and overcome the evading mechanism of the virus and thus the development of drug resistance.

HDAC11 Inhibits Myoblast Differentiation through Repression of MyoD-Dependent Transcription

  • Byun, Sang Kyung;An, Tae Hyeon;Son, Min Jeong;Lee, Da Som;Kang, Hyun Sup;Lee, Eun-Woo;Han, Baek Soo;Kim, Won Kon;Bae, Kwang-Hee;Oh, Kyoung-Jin;Lee, Sang Chul
    • Molecules and Cells
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    • 제40권9호
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    • pp.667-676
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    • 2017
  • Abnormal differentiation of muscle is closely associated with aging (sarcopenia) and diseases such as cancer and type II diabetes. Thus, understanding the mechanisms that regulate muscle differentiation will be useful in the treatment and prevention of these conditions. Protein lysine acetylation and methylation are major post-translational modification mechanisms that regulate key cellular processes. In this study, to elucidate the relationship between myogenic differentiation and protein lysine acetylation/methylation, we performed a PCR array of enzymes related to protein lysine acetylation/methylation during C2C12 myoblast differentiation. Our results indicated that the expression pattern of HDAC11 was substantially increased during myoblast differentiation. Furthermore, ectopic expression of HDAC11 completely inhibited myoblast differentiation, concomitant with reduced expression of key myogenic transcription factors. However, the catalytically inactive mutant of HDAC11 (H142/143A) did not impede myoblast differentiation. In addition, wild-type HDAC11, but not the inactive HDAC11 mutant, suppressed MyoD-induced promoter activities of MEF2C and MYOG (Myogenin), and reduced histone acetylation near the E-boxes, the MyoD binding site, of the MEF2C and MYOG promoters. Collectively, our results indicate that HDAC11 would suppress myoblast differentiation via regulation of MyoD-dependent transcription. These findings suggest that HDAC11 is a novel critical target for controlling myoblast differentiation.

음향 조사에 의한 2002/2003 하계 시기의 남극 남쉐틀랜드 군도와 남오크니섬 사이의 크릴 밀도 (Acoustic Estimate of the Krill (Euphausia superba) Density between South Shetland Islands and South Orkney Islands, Antarctica, During 2002/2003 Austral Summer)

  • 강돈혁;신형철;이윤호;김영신;김수암
    • Ocean and Polar Research
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    • 제27권1호
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    • pp.75-86
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    • 2005
  • Acoustic survey for density and biomass estimate of Antarctic krill, Euphausia superba, was conducted in the large area between South Shetland Islands and South Orkney Islands, during November 30-December 30, 2002. Considering oceanographic and geographic properties, the study area was divided into six sub-regions. Acoustic system and frequency used in the survey were quantitative echo sounder (Simrad Ek 500) and 38, 120-kHz split beam transducers. In order to discriminate krill aggregations in all acoustic signal, difference of mean volume backscattering strength $({\Delta}MVBS)$ method of the two frequencies was introduced. Averaged krill density for the overall surveyed area was $23.5g/m^2$, and spatially averaged estimates of krill density were $44.9g/m^2$ (north of the South Shetland Islands), $30.3g/m^2$ (Bransfield Strait), $11.3g/m^2$ (near the Elephant Island), $13.6g/m^2$ (north of the Elephant Island), $18.1g/m^2$(between Elephant Island and South Orkney Islands) and $21.7g/m^2$(northwest of the South Orkney Islands) at each sub-area. In the two sub-regions with surveyed area, estimated krill biomass in the north of the Elephant Island was 0.315 million tones with a CV of 18.35% $(6,766mile^2)$, and between Elephant Island and South Orkey Islands was 1.26 million tones with a CV of 9.45% $(20,299mile^2)$. As a whole, the krill density in the early summer season was low level, comparing with that of January-February. This suggested that major krill swarms in the around South Shetland Islands were reached in the mid-summer seasons from western part of the Antarctic Peninsula, and the low krill density also affects the density variation of the krill between Elephant Island and South Orkney Islands.