Bioluminescence

Also called bioluminescence. The phenomenon in which living organisms emit light. There are those that are parasitic with luminous bacteria or live in symbiosis with luminous small animals, and those that emit light themselves. Well-known examples of luminous organisms include the golden-spotted fish, fireflies and sea fireflies, and fission plants such as luminous bacteria, flagellated plants, and basidiomycete plants such as Tsukiyotake. Bioluminescence is a highly efficient form of energy conversion in living organisms, and is essentially chemiluminescence. There has been a great deal of research on fireflies and sea fireflies, and the mechanism of luminescence has been elucidated to some extent, but many aspects of other luminous organisms remain unknown. It is thought that all bioluminescence has in common that when one molecule of the luminous substance luciferin is oxidized by one molecule of oxygen in the presence of the oxidase luciferase and adenosine 5'-triphosphate (ATP), one photon is generated and light is emitted. There are still few luminous organisms from which luciferase has been isolated. A microquantification device for ATP or oxygen has been developed that utilizes the luminescence mechanism of fireflies. A fixed amount of firefly luciferin and luciferase are added to the sample, and ATP is quantified by fluorescence measurement, which is expected to have many applications. Green fluorescent protein (GFP), isolated from Aequorea victoria, emits green fluorescence when excited by near-ultraviolet and visible light. The chemical structure of the chromophore ( p -hydroxybenzylideneimidazolinone) is simple, formed by the reaction of three amino acid residues (Ser-Tyr-Gly) in the molecule, and it has the characteristic of emitting light without the aid of external substances. GFP can be used to fluorescently label normal proteins. In other words, a fusion protein of the desired protein with GFP can be created through genetic engineering. GFP labeling of proteins is useful for investigating the intracellular localization of specific proteins using a fluorescent microscope, and is highly valued in the field of cell biology.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

生物ルミネセンスともいう．生物が発光する現象．発光生物には，発光細菌の寄生や発光小動物との共生によるものと，自身の発光によるものとがある．魚類ではキンメモドキ，昆虫類ではホタル，ウミホタル，植物では発光細菌などの分裂植物，鞭毛植物，ツキヨダケなどの担子菌植物などが有名である．生物発光は生体におけるきわめて効率のよいエネルギー変換の一形式であり，本質的には化学ルミネセンスである．ホタルやウミホタルについては数多くの研究が行われ，発光機構も一応解明されたが，そのほかの発光生物については不明な点が多い．発光物質ルシフェリン1分子が酸化酵素ルシフェラーゼとアデノシン5′-三リン酸(ATP)の存在下で，酸素1分子によって酸化される際に，1光子を生成して発光することは，すべての生物発光に共通していると考えられる．ルシフェラーゼが単離された発光生物はまだ少ない．ホタルの発光機構を利用したATP，あるいは酸素の微量定量装置が開発された．試料に一定量のホタルルシフェリンとルシフェラーゼを共存させ，蛍光測定によりATPを定量するもので，その応用が期待される．オワンクラゲから単離された緑色蛍光タンパク質(green fluorescent protein，GFP)は，近紫外および可視光で励起され，緑色の蛍光を発する．発色団の化学構造(p-hydroxybenzylideneimidazolinone)は，分子内の三つのアミノ酸残基(Ser-Tyr-Gly)が反応してできる単純なもので，外界の物質の助けなしに光るという特徴を有する．GFPを使うと通常のタンパク質を蛍光標識することができる．すなわち，遺伝子工学的に，目的とするタンパク質とGFPの融合タンパク質をつくればよいことになる．タンパク質のGFP標識法は，特定のタンパク質の細胞内局在を蛍光顕微鏡で調べるのに有用で，細胞生物学分野で重宝されている．

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