細胞生物學 : 粒線體 葉綠體 中央研究院植物暨微生物學研究所 副研究員謝明勳 e-mail: ming@gate.sinica.edu.tw
Energy flow and chemical recycling in ecosystems 葉綠體 光合作用 粒線體 呼吸作用
阿拉伯芥 Arabidopsis thaliana: 當代分子遺傳研究最受歡迎的模式植物 - 生活周期短 : 約 6-8 周 - 植物體小 : 成株約 30 公分高 - 種子產量高 : 每棵植物可產生數千顆種子 - 基因體小 :5 對染色體, 約 1.25 x 10 8 鹼基對 (base pairs, bp) - 基因體已定序完成 : 約 2 萬 6 千個基因 - 知識 技術發展迅速 : 研究者眾 - 大量的突變種可供研究 : 阿拉伯芥種源中心
Transmission electron micrograph of a cell in an Arabidopsis leaf
Electron micrograph of a starch-containing chloroplast in an Arabidopsis leaf 澱粉粒
在演化上, 植物細胞內的 粒線體 葉綠體是怎麼來的?
Endosymbiosis and The Origin of Eukaryotes ( 真核生物的起源 ) 內共生假說 The mitochondria of eukaryotes evolved from a-proteobacteria (α- 變形菌 ) living within their host cell. The chloroplasts of eukaryotes evolved from endosymbiotic cyanobacteria ( 藍綠藻 ).
內共生假說的證據?
The mitochondrion, site of cellular respiration
葉綠體與粒線體都有自己的 DNA DNA in chloroplasts
Mitochondria and chloroplasts are semiautonomous organelles 阿拉伯芥的細胞核基因體 :125 Mb; ~30,000 個基因 阿拉伯芥的葉綠體內約有 3,500 種蛋白質阿拉伯芥的葉綠體基因體 (154 kb):~87 個基因 阿拉伯芥的粒線體內約有 2,500 種蛋白質阿拉伯芥的粒線體基因體 (367 kb):~57 個基因
人類粒線體的 genome 有多少基因?
Evolutionary trend towards reducing organelle gene content Genome Rikettsia prowazekii (alpha proteobacterium) Reclinomonas americana (protozoan) mitochondria Marchantia polymorpha (liverwort) mitochondria Arabidopsis thaliana mitochondria Homo sapiens mitochondria Protein coding genes 832 62 64 57 13 Similar trend in the chloroplasts
Human Mitochondrial Genome 人類粒線體的基因體全長 16.5 kb, 只有 13 個可以轉譯成蛋白質的基因 The genome of human mitochondria contains 16,569 base pairs of DNA organized in a closed circle. These encode: 2 ribosomal RNA (rrna) molecules 22 transfer RNA (trna) molecules 13 polypeptides 7 subunits that make up the mitochondrial NADH dehydrogenase 3 subunits of cytochrome c oxidase 2 subunits of ATP synthase cytochrome b 絕大部分的粒線體蛋白質, 都是在細胞質內合成, 然後運送到粒線體內
粒線體與葉綠體內, 基因的組成 基因的表現與核醣體的構造, 都與原核生物類似 原核生物核醣體 (ribosome): 70S 30S small subunit 50S large subunit 真核生物核醣體 (ribosome): 細菌的核醣體是抗生素的主要標的之一
粒線體的基因與演化 粒線體的構造與功能 粒線體為什麼叫做粒線體?
粒狀 線狀的胞器 英文中的 粒線體 (mitochodrion, 複數形式為 mitochondria ) 一詞是由希臘語中的 線 ( μίτος 或 mitos ) 和 顆粒 ( χονδρίον 或 chondrion ) 組合而成的
Embryonic Swiss Mouse Fibroblast Cells The extensive mitochondrial network and its physical relation to the cell... zeiss-campus.magnet.fsu.edu
A digital image of the mitochondrial network found in the ovarian tissue from a mountain goat relative, known as the Himalayan Tahr
microscopyu.com
Cellular roles of mitochondrial dynamics. Westermann B J. Biol. Chem. 2008;283:13501-13505 2008 by American Society for Biochemistry and Molecular Biology
An overview of cellular respiration
An overview of the citric acid (Krebs) cycle
Chemiosmosis couples the electron transport chain to ATP synthesis
Electron transport chain - oxidative phosphorylation kda Polypeptides Complex I NADH dehydrogenase 800 25 (7) Complex II Succinate dehydrogenase 140 4 Complex III Cytochrome C oxidoreductase 250 9-10 (1) Complex IV Cytochrome C oxidase 170 13 (3) Complex V ATP synthase 380 12-14 (2)
葉綠體 (chloroplast) 的構造 Thylakoids 囊狀膜 Stroma thylakoids Granal 葉綠餅 thylakoids Stroma 基質 英文 chloroplast 源於希臘語 χλωροπλάστης, 該詞由 綠 ( chloros 或 χλωρός ) 和 成型 ( plastis 或 πλάστης ) 組合而成
Genes of cyanobacterial origin and the intracellular targeting of their products in Arabidopsis Lots of genes have been transferred to the nuclear genome. Leister (2003)
Mitochondria and chloroplasts are semiautonomous organelles 阿拉伯芥的細胞核基因體 :125 Mb; ~30,000 個基因 阿拉伯芥的葉綠體內約有 3,500 種蛋白質阿拉伯芥的葉綠體基因體 (154 kb):~87 個基因 阿拉伯芥的粒線體內約有 2,500 種蛋白質阿拉伯芥的粒線體基因體 (367 kb):~57 個基因
Chloroplasts are highly dependent on nuclear genes -- 葉綠體內,90% 以上的蛋白質是由細胞核內的基因所合成 -- 這些蛋白質在細胞質內合成之後, 再經由特定的運送途徑, 運送到葉綠體內
Translocation into the chloroplast of a protein destined for the stroma
VAC1 transit peptide-gfp is localized to the chloroplast VAC1 protein TP TP GFP (green fluorescent protein)
Roger Tsien 錢永健 Agar Plate of Fluorescent Bacteria Colonies
會發綠色螢光的基因轉殖植物
會發綠色螢光的基因轉殖動物
An overview of photosynthesis: cooperation of the light reactions and the Calvin cycle 光合作用 : 將光能轉變為化學能 光反應碳反應 ( 暗反應 )
The light reactions and chemiosmosis: the organization of the thylakoid membrane 光反應
碳反應 ( 暗反應 ) The Calvin cycle 5C 3C 3C 3C Rubisco: Ribulose-1,5- bisphosphate carboxylase oxygenase 5C 5C 6C 6C 3C 3C 4C 5C 5C 7C 7C 5C 5C
澱粉與蔗糖的合成 葡萄糖 6C 6C 6C 光合作用的產物以澱粉的形式在葉綠體內儲存 3C 6C 3C 6C 6C 葡萄糖 6C 果糖 光合作用的產物以蔗糖的形式在植物體內運送 6C 6C
Electron micrograph of a starch-containing chloroplast in an Arabidopsis leaf 澱粉粒
Rubisco is probably the most abundant protein on earth Rubisco: Ribulose-1,5-bisphosphate carboxylase oxygenase
Photorespiration 光呼吸作用 Rubisco: ribulose-1,5-bisphosphate carboxylase/oxygenase 消耗 氧 產生 二氧化碳 跟 阿摩尼亞
Peroxisomes and mitochondria are often closely associated with chloroplasts in photosynthetic cells crystal of catalase
A review of photosynthesis 五碳糖 三碳糖 C3 光合作用
C3 光合作用 C4 光合作用 CAM 光合作用
C 4 leaf anatomy and the C 4 pathway C4 光合作用 葉肉細胞 四碳糖 維管束鞘細胞
C4 植物維管束鞘細胞的葉綠體沒有葉綠餅
The C4 photosynthetic pathway 葉肉細胞 4C 4C 3C 4C 維管束鞘細胞 3C The C4 cycle concentrates CO2 in bundle sheath cells
Some C4 crop plants Maize Sugarcane Sorghum Zea mays Saccharum officinarum Sorghum vulgare
Crassulacean acid metabolism (CAM) The CAM mechanism enables plants to improve water use efficiency
C 4 and CAM photosynthesis compared 景天科 CRASSULACEAE crassulacean acid metabolism
葉綠體的避光反應 Chloroplast distribution in photosynthesizing cells of the duck weed Lemna accumulation response avoidance response
Arabidopsis NPL1: A Phototropin Homolog Controlling the Chloroplast High-Light Avoidance Response Takatoshi Kagawa, Tatsuya Sakai, Noriyuki Suetsugu, Kazusato Oikawa, Sumie Ishiguro, Tomohiko Kato, Satoshi Tabata, Kiyotaka Okada, Masamitsu Wada4
Chloroplast movement Photoperception Phototropin a blue light receptor Signal transduction? Chloroplast movement Actin filaments
葉綠體的分裂 WT ftsz mutant single giant chloroplast
Many important reactions occur in the chloroplast Photosynthesis Amino acid metabolism Carbohydrate metabolism Fatty acid metabolism Secondary metabolism Redox regulation etc 光合作用氨基酸代謝醣類代謝脂肪酸代謝次級代謝氧化還原調控... 等等
Glycine Cysteine O-Acetylserine Serine Asparagine Glucose Fructose 1,6-BP Anthranilate Prephenate 3-Phosphoglycerate Phosphoenolpyruvate Pyruvate Alanine Acetyl-CoA * Tryptophan Tyrosine Erythrose 4-phosphate Chorismate DAHP Shikimate Phenylalanine * Aspartate Oxaloacetate Citrate Aspartate 4-phosphate Malate Aspartate 4-semialdehyde Homoserine 2,3-Dihydro- Fumarate dipicolinate Homoserine Succinate 4-phosphate Cysteine DAP Isocitrate Oxalosuccinate a-ketoglutarate Proline Glutamate Pyruvate * Threonine a-ketobutyrate Cystathionine Homocystine Methionine Pyruvate * Lysine * Ornithine Citrulline Arginine Glutamine * Histidine * Leucine Valine * Isoleucine * * essential amino acid
許多與必需氨基酸合成有關的酵素, 正是殺草劑的作用目標
Roundup : the most used herbicide in the USA and the most-sold agrichemical of all time Conventional weed control Roundup Ready system Roundup is the brand name of a systemic, broad-spectrum herbicide produced by the U.S. company Monsanto and contains the active ingredient glyphosate.
Aromatic amino acid biosynthesis pathways 芳香族氨基酸的合成途徑 Glyphosate is a competitive inhibitor of the enzyme enolpyruvyl shikimate-3- phosphate synthase (EPSPS)
Glyphosate (Roundup) is a competitive inhibitor of the enzyme EPSPS How do you develop a glyphosate-resistant crop?
Development of Roundup Ready crops 1. Screen for Roundup (glyphosate) resistant bacterium from an Agrobacterium species the unusual form of EPSP synthase caused the resistance 2. The gene was isolated and modified and then transferred into plants. CaMV35S promoter CTP4 A. tumefaciens CP4 mutant EPSPS NOS terminal Construct used to generate Roundup Ready crops
Mutations in EPSP synthase render the enzyme insensitive to the inhibitor glyphosate Roundup Ready Roundup : Glyphosate
Summary: -- 粒線體與葉綠體的形態 構造與功能 -- 粒線體與葉綠體的基因 -- 粒線體與葉綠體的演化 -- 葉綠體內氨基酸的代謝與抗殺草劑的基因轉殖作物 孟山都 (Monsanto) 的 Roundup 與 Roundup Ready