Bacteria - Recent

Japanese: 細菌 - さいきん

Also called bacteria. Single-celled organisms consisting of prokaryotic cells. Usually refers to eubacteria, but may also include actinomycetes, filamentous fungi, spirochetes, and purple bacteria. They are 0.2-10 μm in size, have a cell membrane and cell wall, but do not have structures such as a nucleus, chloroplasts, or mitochondria. They are broadly classified into cocci, rods, and spirals depending on their shape. They are also broadly classified into gram-positive and gram-negative bacteria by gram staining. Staphylococcus aureus and streptococci are gram-positive bacteria, and are highly sensitive to penicillin. Escherichia coli, Salmonella, and Shigella are gram-negative bacteria. They grow by binary cell division or form endospores. There are autotrophic bacteria that grow only on inorganic matter, and heterotrophic bacteria that require organic matter, and they obtain energy by fermentation and respiration (anaerobic bacteria, aerobic bacteria). Some are parasitic and pathogenic. They play a major role in the circulation of materials on Earth, and are used in agriculture and industry for fermentation and wastewater treatment, and in medicine for the production of antibiotics and vitamins, and for the manufacture of useful proteins through genetic engineering. They are also used as tools in biological research into the mechanisms of disease onset, immunity, and genetics. →Autotrophy/Heterotrophy →Related topics Chlamydia | Prokaryotes | Bacteriology | Plant bacterial diseases | Phytoplasma | Mycoplasma

Source : Heibonsha Encyclopedia About MyPedia Information

Japanese:

バクテリアとも。原核細胞からなる単細胞生物。普通は真正細菌類を指すが，放線菌，糸状菌，スピロヘータ，紅色細菌等を含めることもある。大きさは幅0.2〜10μmで，細胞膜と細胞壁を持つが，核・葉緑体・ミトコンドリアなどの構造を持たない。形態によって，球菌，杆(かん)菌，らせん菌等に大別される。またグラム染色によってグラム陽性菌とグラム陰性菌とに大別される。ブドウ球菌，連鎖球菌などはグラム陽性菌で，ペニシリンなどに対する感受性が高い。大腸菌，サルモネラ菌，赤痢菌などはグラム陰性菌。細胞の２分裂により増殖，または内生胞子を形成。無機物のみで発育する独立栄養菌，有機物を必要とする従属栄養菌があり，発酵・呼吸（嫌気(けんき)性菌，好気性菌）によってエネルギーを得る。寄生するもの，病原性を有するものもある。地球上の物質循環に大きな役割を果たし，発酵，汚物処理などで農工業に，抗生物質，ビタミンの生産，遺伝子工学での有用タンパク質の製造などで医薬学に利用される。また，発病や免疫の機序，遺伝の機序などの生物学研究の道具ともなっている。→独立栄養／従属栄養
→関連項目クラミジア｜原核生物｜細菌学｜植物細菌病｜ファイトプラズマ｜マイコプラズマ

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