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''Neisseria gonorrhoeae'', also known as ''gonococci'' (plural), or ''gonococcus'' (singular), is a species of Gram-negative coffee bean-shaped diplococci bacteria responsible for the sexually transmitted infection gonorrhea. ''N. gonorrhoeae'' was first described by Albert Neisser in 1879. == Microbiology == ''Neisseria'' are fastidious Gram-negative cocci that require nutrient supplementation to grow in laboratory cultures. To be specific, they grow on chocolate agar with carbon dioxide. These cocci are facultatively intracellular and typically appear in pairs (diplococci), in the shape of coffee beans. Of the eleven species of ''Neisseria'' that colonize humans, only two are pathogens. ''N. gonorrhoeae'' is the causative agent of gonorrhea (also called "The Clap") and is transmitted via sexual contact. ''Neisseria'' is usually isolated on Thayer-Martin agar (or VPN agar)—an agar plate containing antibiotics (vancomycin, colistin, nystatin, and trimethoprim) and nutrients that facilitate the growth of ''Neisseria'' species while inhibiting the growth of contaminating bacteria and fungi. Further testing to differentiate the species includes testing for oxidase (all clinically relevant ''Neisseria'' show a positive reaction) and the carbohydrates maltose, sucrose, and glucose test in which ''N. gonorrhoeae'' will oxidize (that is, utilize) only the glucose. ''N. gonorrhoeae'' are non-motile and possess type IV pili to adhere to surfaces. The type IV pili operate mechanistically similar to a grappling hook. Pili extend and attach to a substrate that signals the pilus to retract, dragging the cell forward. ''N. gonorrhoeae'' are able to pull 100,000 times their own weight, and it has been claimed that the pili used to do so are the strongest biological motor known to date, exerting one nanonewton. ''N. gonorrhoeae'' has surface proteins called Opa proteins, which bind to receptors on immune cells. In so doing, ''N. gonorrhoeae'' is able to prevent an immune response. The host is also unable to develop an immunological memory against ''N. gonorrhoeae'' – which means that future reinfection is possible. ''N. gonorrhoeae'' can also evade the immune system through a process called antigenic variation, in which the ''N. gonorrhoeae'' bacterium is able to alter the antigenic determinants (sites where antibodies bind) such as the Opa proteins and Type IV pili that adorn its surface. The many permutations of surface proteins make it more difficult for immune cells to recognize ''N. gonorrhoeae'' and mount a defense.〔(STI Awareness: Gonorrhea ). Planned Parenthood Advocates of Arizona. 11 April 2011. Retrieved 31 August 2011.〕 ''N. gonorrhoeae'' is naturally competent for DNA transformation as well as being capable of conjugation. These processes allow for the DNA of ''N. gonorrhoeae'' to acquire or spread new genes. Especially dangerous from the aspect of healthcare is the ability to conjugate, since this can lead to antibiotic resistance. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Neisseria gonorrhoeae」の詳細全文を読む スポンサード リンク
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