• Applied Microscopy
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• 제28권2호
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• pp.159-170
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• 1998

The glandular secretory system of the capitate gandular trichomes in leaf of Thymus quinquecostatus Celakovsky was examined by transmission electron microscope. The glandular trichome was consisted of three cell layers; an basal cell layer, a stalk cell with single-celled intermediate layer and a discoid secretory layer with thickened cuticle. The secretory cell was dense, rich in mitochondria, rER, plastds, Golgi complex and had many vesicular structure. Typical plastids with reticulate body and plastoglobule were present in glandular trichome. The tytoplasm of secretory cell was filled with osmiophilic secretory materials. The secretory vesicles, originated from Golgi complex, appeared as membrane bounded vesicles and secreted to the outer wall surface. The presences of well developed rER, mitochondria, Golgi complex, and membrane-bounded vesicles fused with plasmalemma in the secreting cells indicate that the granulocrine mechanism of secretion was occurring in T. quinquecostatus. Subcuticular cavity was developed between the cuticular layer and the secretory cell wall, and it formed above the secretory cell upon separation of cuticle-wall.

• The Plant Pathology Journal
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• 제40권2호
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• pp.99-105
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• 2024

Land plants produce glucose (C₆H₁₂O₂) through photosynthesis by utilizing carbon dioxide (CO₂), water (H₂O), and light energy. Glucose can be stored in various polysaccharide forms for later use (e.g., sucrose in fruit, amylose in plastids), used to create cellulose, the primary structural component of cell walls, and immediately metabolized to generate cellular energy, adenosine triphosphate, through a series of respiratory pathways including glycolysis, the tricarboxylic acid cycle, and oxidative phosphorylation. Additionally, plants must metabolize glucose into amino acids, nucleotides, and various plant hormones, which are crucial for regulating many aspects of plant physiology. This review will summarize the biosynthesis of different plant hormones, such as auxin, salicylic acid, gibberellins, cytokinins, ethylene, and abscisic acid, in relation to glucose metabolism.

• Applied Microscopy
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• 제33권1호
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• pp.79-92
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• 2003

Citrus reticulata 감과 과피조직 내에서 탈리를 전후하여 신속하게 진행되는 특정 미세구조의 분화양상을 전자현미경적으로 연구하였다. 특히, 색소체 전환이 진행되어 뚜렷한 외과피층을 이루는 후각세포 내에서 일어나는 미세소기관 분해물질의 형성 및 특성에 초점을 두어 연구하였다. 색 변화가 수반된 발달 중의 외과피 유세포들은 세포벽이 비후되면서 1차공역이 잘 발달하는 후각세포로 분화하며, 대부분의 색소체는 유색체로 전환되어 티라코이드는 거의 소실되고 지질입자를 다량 함유하는 불규칙적인 형태로 변형되었다. 이때 세포막이나 액포막에서는 국부적으로 형성된 수많은 소낭들이 집적되어 세포질 내부로 이동하였고, 세포간 1차공역에 발달하는 원형질연락사를 통한 소낭의 집적현상 또한 빈번히 일어났다. 집적된 소낭들은 융합되어 전자밀도가 높은 구형 또는 일정한 형태가 없는 구조(EDB)로 되며, 이동하여 엽록체, 미토콘드리아 등의 주요 세포소기관을 점차 포위하였다. 소액포들은 융합하여 거대액포가 되며, 세포질 및 EDB에 포위된 소기관들은 점차 분해되기 시작하였다. EDB는 리파제 확인실험에 의해 지질성 물질로 이루어진 구조로 확인되었다. 과피발달 초기에 선행된 중과피 분화는 세포 내에서 급격히 진행된 용해현상에 의해 수많은 소액포들로 이루어진 거대한 세포 공강을 형성하며 밀착되어 불규칙적인 세포벽과 함께 해면성으로 되었다. 이와 같이 본 연구에서는 감과가 식물체에서 분리되기 직전에서부터 탈리 후까지 일어나는 과피의 발달 및 노화현상을 추적하였다.

• Applied Microscopy
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• 제41권1호
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• pp.55-60
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• 2011

부엽성 개구리밥은 엽상체, 연결사, 뿌리로 이루어진 축소된 수생식물로 엽상체는 특정한 시기에 물속에 가라앉는 휴면구조인 잠아를 형성한다. 식물세포의 분화발달에서 중요한 기능을 수행하는 색소체는 개구리밥의 거의 모든 기관에 분포하며, 특히 잠아 형성 및 수중 침강에 있어서 이들 색소체와의 연계성이 보고되어 있다. 본 연구에서는 개구리밥 식물체 내 모든 조직을 구성하는 각각의 세포들을 대상으로 색소체 특성에 초점을 두어 전자현미경으로 연구하였다. 생장 중의 엽상체는 활발한 분열로 개체를 계속 증식시키고, 특정 시기에 잠아원기를 형성하여 엽상체-잠아원기-잠아-엽상체원기-엽상체의 분화과정을 반복한다. 개구리밥 조직에 발달하는 색소체는 전색소체, 엽록체, 전분체로 크게 대별되며, 특히 색소체의 크기, 틸라코이드막계, 녹말입자 형성 등은 엽상체와 잠아 조직 간에 뚜렷한 차이를 보인다. 엽상체 및 잠아원기 엽육세포에는 비교적 작은 전색소체가 세포질에 분산되어 다수 분포하고, 기질 내에는 틸라코이드막계 및 녹말입자가 거의 형성되지 않는다. 반면, 생장 중의 엽상체에는 엽록체들이 중앙의 큰 액포를 따라 위치하고, 기질에는 그라나를 형성하는 틸라코이드막계가 발달한다. 유사한 형태의 엽록체가 근관에 발달하나 뿌리의 피층 및 연결사 색소체에는 녹말입자는 거의 나타나지 않는다. 잠아원기와는 대조적으로 잠아조직에는 매우 큰 전분체들이 축적된다. 이들 전분체는 기질에 내부 막의 분화 없이 당 축적에 의한 거대 녹말입자를 형성하여 무거운 구조가 된다. 이와 같이 엽상체, 연결사, 뿌리조직에 형성된 엽록체로 광합성을 수행하여 생장발달에 필요한 에너지를 생성 활용하는 반면, 잠아는 에너지 생성이나 활용이 아닌 휴면상태 유지에 필요한 독특한 구조로 각각 발달한다. 축소된 개구리밥 식물체 내 색소체 및 각각의 세포와 조직들은 최소한의 구조로 분화되나 기능은 고도로 분업화된 독특한 수생식물이라 할 수 있다.

• ALGAE
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• 제28권1호
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• pp.83-92
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• 2013

The descriptions of galls, or tumors, in red algae have been sparse. K$\ddot{u}$tzing (1865) observed possible galls of Bostrychia but only presented a drawing. Intensive culture observations of hundreds of specimens of the genus Bostrychia over many years have revealed that galls appeared in only a small subset of our unialgal cultures of B. kelanensis, Bostrychia moritziana/radicans, B. radicosa, B. simpliciuscula, and B. tenella and continued to be produced intermittently or continuously over many years in some cultures but were never seen in field specimens. Galls appeared as unorganized tissue found primarily on males and bisexuals, but occasionally on females and tetrasporophytes. The gall cells usually were less pigmented than neighboring tissue, but contained cells with fluorescent plastids and nuclei. The galls were not transferable to other potential hosts. Galls could be produced from gall-free tissue of cultures that originally had galls even after transfer to new culture dishes. Electon microscopy of galls on one isolate (3895) showed that virus-like particles are observed in some gall cells. It is possible that a virus is the causative agent of these galls.

• Applied Microscopy
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• 제28권3호
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• pp.399-414
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• 1998

Glandular trichomes present on the leaf surface of Drosera capensis were examined using transmission electron microscopy. A large number of stalked glands exist on the adaxial surfaces of the leaf blade. The secretory head is composed of two layers of secretory cells, one layer of middle cells, and the inner tracheids. The secretory cells contain rough endoplasmic reticulum, mitochondria, plastids, Golgi apparatus, and vacuoles. The secretory cells show prominent cell wall ingrowth, and thick cuticle restricted on the subcuticular wall. Frequently, the cuticle has some pores, canal-like structures, showing electron -dense granules being penetrated through them. Ultrastructural localization using diaminobenzidine showed the electron-dense deposits in the vacuole. No peroxidase activity was seen in the cell wall and cytolasm. The activity of peroxidase (POX) isozymes in Drosera which isoelectric point (pI) is 3.6 and some anionic POX isozymes which pIs are laid between 3.6 and 4.6 were especially increased according to the development and the formation of glandular trichomes. Also, the activity of some POX isozymes which isoelectric points are laid between 4.6 and 5.1 were increased in the regions of leaves which has trichomes.

• ALGAE
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• 제18권3호
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• pp.183-190
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• 2003

Except for a group I intron in trnL-uaa occuring in eubacteria and plastids, group I introns are rarely documented in plastid genomes. Here, we report that a green alga, Caulerpa sertularioides, contains three group IA3 introns in the 16S gene (cpSSU), CS-cpSSU.i1, CS-cpSSU.i2 and CS-cpSSU.i3. Each intron has an open reading frame with LAGLIDADG motifs. CS-cpSSU.i1orf and CS-cpSSU.i3orf occur at Loop 6 in the intron secondary structure and CScpSSU. i2orf at Loop 8. CS-cpSSU.i1orf and CS-cpSSU.i2orf contain both LAGLI-DADG motifs but CS-cpSSU.i3orf has only one. CS-cpSSU.i1 and CS-cpSSU.i2 share the insetion sites and the ORFs at Loop 6 and 8 with CpSSU·1 and CpSSU·2 introns of Chlamydomonas pallidostigmatica (Chlorophyceae). In contrast, CS-cpSSU.i3, containing 28 copies of GAAATAT at Loop 6, is a novel intron found only in Caulerpa sertularioides. Possible scenarios of the evolution of the three introns and their possible use in systematic research are discussed.

• Journal of Plant Biology
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• 제36권3호
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• pp.285-292
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• 1993

Cellular compatibility in the self-parasitism of Cuscuta australis R. Brown was studied at the ultrastructural level. The front cells of the haustorium penetrated the host stems independently grew within the host tissues and transformed into elongate, filamentous hyphae. Each hyphal cells contained a large nucleus and dense cytoplasm with abundant cell organelles. Multilamellar structures were contained in the cytoplasm and cell walls of the penetrating hyphal cells. When the hyphal cells did not yet invade the host cells, the middle lamella and the fused cellulosic cell walls of the two partners at the host-parasite interface were preserved well. As the invasion of the parasitic hyphal cells progressed, however, the middle lamella was not found at the interface and the host cell walls and plasma membranes were partially broken down. A hyphal cell penetrated deeply into the host cell had a more darkly stained cytoplasm with numerous of cell organelles. In the host cells attacked by the hyphal cells the limiting membranes of plastids were broken down and several vesicles were arrayed near the cell walls. No plasmodesmatal connections between the host and parasite cell walls were found; however, half-plasmodesmata were observed frequently on the side of the hyphal cell walls. These results suggested that the compatibility response in the self-parasitism of Cuscuta was expressed by cell walls, not by plasmodesmata, between the host and the parasite cells.

• Animal cells and systems
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• 제10권4호
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• pp.197-201
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• 2006

Diaminopimelate decarboxylase (DAPDC, EC 4.1.1.20) catalyzes the conversion of diaminopimelate into lysine (Lys), which is the last step in Lys biosynthetic pathway. The genes for DAPDC have been reported in many bacteria, and more recently in Arabidopsis. Here we report characterization of a gene for DAPDC from rice (OsDAPDC). Sequence analysis of a cDNA clone revealed a full-length open reading frame for OsDAPDC that encoded 490 amino acids, approximately 53.2 kDa protein. The OsDAPDC protein contains a consensus binding site for pyridoxal-5'-phosphate as a cofactor and has a sequence at the amino terminus that resembles a transit peptide for localization to plastids, similar to that of Arabidopsis. Single gene encoding DAPDC was found in chromosome II in rice. The predicted amino acid sequence of OsDAPDC is highly homologous to that of the enzymes for DAPDC encoded by lysA of many bacteria. Expression of OsDAPDC in lysA mutants of Escherichia coli shows that the gene is able to functionally complement the mutants. These results suggest that OsDAPDC encodes a protein for diaminopimelate decarboxylase in rice.

• Applied Microscopy
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• 제29권1호
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• pp.125-136
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• 1999

제라늄(Polargonium peltatum) 분비모의 미세구조를 광학현미경과 주사전자현미경을 사용하여 살펴보았다. Pelargonium peltatum의 분비모는 형태와 크기에 따라 short-stalked capitate glands (Type I)와 long-stalked capitate glands (Type II)의 두 가지 종류로 구분할 수 있었다. 두 종류의 분비모는 모두 배축면의 엽백과 엽병에 많이 분포하였다. 분비모는 1개의 분비세포, 3개의 병세포, 1개의 기부 세포로 이루어져 있었으며, 분비세포는 다수의 활면소포체와 색소체, 액포, 골지장치, 미토콘드리아 등을 가지고 있었다. 분비세포의 액포 내에서는 전자밀도가 높은 물질이 자주 관찰되었는데, 이들은 분비모의 주된 분비전구물질인 phenolic compound인 것으로 사료된다.