WordNet

reckoned in a direction opposite to that regarded as positive; "negative interest rates"
a piece of photographic film showing an image with light and shade or colors reversed
a reply of denial; "he answered in the negative"
not indicating the presence of microorganisms or disease or a specific condition; "the HIV test was negative" (同)disconfirming
having a negative charge; "electrons are negative" (同)electronegative, negatively charged
characterized by or displaying negation or denial or opposition or resistance; having no positive features; "a negative outlook on life"; "a colorless negative personality"; "a negative evaluation"; "a negative reaction to an advertising campaign"
expressing or consisting of a negation or refusal or denial
having the quality of something harmful or unpleasant; "ran a negative campaign"; "delinquents retarded by their negative outlook on life"
less than zero; "a negative number"
not aerobic; "isometric exercises are anaerobic"
living or active in the absence of free oxygen; "anaerobic bacteria" (同)anaerobiotic
(microbiology) single-celled or noncellular spherical or spiral or rod-shaped organisms lacking chlorophyll that reproduce by fission; important as pathogens and for biochemical properties; taxonomy is difficult; often considered to be plants (同)bacterium
Danish physician and bacteriologist who developed a method of staining bacteria to distinguish among them (1853-1938) (同)Hans C. J. Gram
a metric unit of weight equal to one thousandth of a kilogram (同)gramme, gm, g

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『否定の』,反対の / 『消極的な』,控えめの / 陰電気の;(数値が)負の,マイナスの(minus);(写真が)陰画の,ネガの;(医学検査結果が)陰性の / 『否定』,拒否,「いやだ」と言うこと / 否定語[句] / 《the~》(特に討論会の)反対者側,反対派 / (電気分解に用いる)陰極板 / (数値の)負数 / (写真の)陰画,ネガ / 《しばしば受動態に用いて》…‘に'反対投票をする / =negate
嫌気性の
『バクテリア』,細菌

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/06/25 11:34:01」(JST)

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Aerobic and anaerobic bacteria can be identified by growing them in liquid culture:
1: Obligate aerobic (oxygen-needing) bacteria gather at the top of the test tube in order to absorb maximal amount of oxygen.
2: Obligate anaerobic bacteria gather at the bottom to avoid oxygen.
3: Facultative bacteria gather mostly at the top, since aerobic respiration is the most beneficial one; but, as lack of oxygen does not hurt them, they can be found all along the test tube.
4: Microaerophiles gather at the upper part of the test tube but not at the top. They require oxygen but at a low concentration.

5: Aerotolerant bacteria are not affected at all by oxygen, and they are evenly spread along the test tube.

An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It may react negatively or even die if oxygen is present, which means that it can perform its bodily functions better in the absence of oxygen. Most such species are unicellular microbes, though some are near-microscopic metazoa^[vague] and some deep-sea worms.^[which?] Some largely unicellular anaerobic microbes are protozoans, but most of the anaerobic microbes are bacteria or Archaea. For practical purposes there are three categories:

obligate anaerobes, which are harmed by the presence of oxygen
aerotolerant organisms, which cannot use oxygen for growth, but tolerate the presence of it
facultative anaerobes, which can grow without oxygen but can utilize oxygen if it is present

In human beings these organisms are usually found in the gastrointestinal tract.^[1] Some anaerobic bacteria produce clinically important toxins (e.g., tetanus).

Metabolism[edit]

Obligate anaerobes may use fermentation or anaerobic respiration.
Aerotolerant organisms are strictly fermentative.
In the presence of oxygen, facultative anaerobes use aerobic respiration; without oxygen, some of them ferment; some use anaerobic respiration.

Fermentation[edit]

There are many anaerobic fermentative reactions.

Fermentative anaerobic organisms mostly use the lactic acid fermentation pathway:

C₆H₁₂O₆ + 2 ADP + 2 phosphate → 2 lactic acid + 2 ATP

The energy released in this equation is approximately 150 kJ per mol, which is conserved in regenerating two ATP from ADP per glucose. This is only 5% of the energy per sugar molecule that the typical aerobic reaction generates.

Plants and fungi (e.g., yeasts) in general use alcohol (ethanol) fermentation when oxygen becomes limiting:

C₆H₁₂O₆ + 2 ADP + 2 phosphate → 2 C₂H₅OH + 2 CO₂↑ + 2 ATP

The energy released is about 180 kJ per mol, which is conserved in regenerating two ATP from ADP per glucose.

Anaerobic bacteria and archaea use these and many other fermentative pathways, e.g., propionic acid fermentation, butyric acid fermentation, solvent fermentation, mixed acid fermentation, butanediol fermentation, Stickland fermentation, acetogenesis, or methanogenesis.

Culturing anaerobes[edit]

Since normal microbial culturing occurs in atmospheric air, which is an aerobic environment, the culturing of anaerobes poses a problem. Therefore, a number of techniques are employed by microbiologists when culturing anaerobic organisms, for example, handling the bacteria in a glovebox filled with nitrogen or the use of other specially sealed containers, or techniques such as injection of the bacteria into a dicot plant, which is an environment with limited oxygen. The GasPak System is an isolated container that achieves an anaerobic environment by the reaction of water with sodium borohydride and sodium bicarbonate tablets to produce hydrogen gas and carbon dioxide. Hydrogen then reacts with oxygen gas on a palladium catalyst to produce more water, thereby removing oxygen gas. The issue with the Gaspak method is that an adverse reaction can take place where the bacteria may die, which is why a thioglycollate medium should be used. The Thioglycollate supplies a medium mimicking that of a Dicot, thus providing not only an anaerobic environment but all the nutrients needed for the bacteria to thrive.^[2]

Antibiotic potency[edit]

Certain antibiotics may or may not be effective against anaerobes or aerobes depending on the intracellular environment, cellular permeability, or enzymes produced by the organism. A few well-described mechanisms have been proposed as to why an anaerobe may or may not be susceptible to a given antibiotic; however, a few remain unclear.

Cephamycins[edit]

A specific class of β-lactam antibiotics called cephamycins (cefoxitin, cefotetan…) are particularly effective against anaerobes because of their ability to maintain structural integrity in the presence of plasmid and chromosomally-mediated β-lactamases.^[3] Although cephamycins are typically effective against anaerobes, resistance can arise due to decreased cell permeability or production of different penicillin binding proteins (PBP).^[4]

Metronidazole[edit]

Metronidazole, another antibiotic which has proven to be effective specifically against anaerobes, is a prodrug where its antimicrobial properties are only effective in anaerobic environments. Once inside the cell, metronidazole is metabolized and partially reduced by ferredoxin, a major component involved in the anaerobic electron transport chain.^[5] Metronidazole metabolites become incorporated into cellular DNA and form unstable molecules which inhibit protein synthesis ultimately killing the cell.^[6] Because metronidazole requires a reduced environment unique to anaerobes, it is not effective against aerobic bacteria.

Aminoglycosides[edit]

A major class of antibiotics, the aminoglycosides (streptomycin, kanamycin, etc.) are not effective against anaerobic bacteria because of their inability to reach the ribosome. In order to enter a cell, aminoglycosides require an energy-dependent phase using oxygen or nitrate in electron transport functions. Because anaerobes do not utilize oxygen or nitrate for electron transport mediated functions, aminoglycosides cannot enter anaerobic cells to inhibit ribosomal activity.^[7]

References[edit]

^ "Anaerobic bacteria – Overview".
^ "GasPak System". Accessed May 3, 2008.
^ Bryan, L.E.; S.K. Kowand (1979). "Mechanism of Aminoglycoside Antibiotic Resistance in Anaerobic Bacteria: Clostridium Perfringens and Bacteroides Fragilis". Antimicrobial Agents and Chemotherapy. 1 15: 7–13.
^ Rasmussen, B.A; Bush, Tally (1994). Clinical Infectious Diseases 24: 110–20. |accessdate= requires |url= (help)
^ Bryan, L.E.; S.K. Kowand (1979). "Mechanism of Aminoglycoside Antibiotic Resistance in Anaerobic Bacteria: Clostridium Perfringens and Bacteroides Fragilis". Antimicrobial Agents and Chemotherapy. 1 15: 7–13.
^ Bosso, John A.; Randall A. Prince (1990). "Anti-Anaerobic Antimicrobial Agents: Cefoxitin, Cefotetan, Clindamycin, and Metronidazole". Texas Heart Institute Journal. 2 17: 77–85.
^ Bosso, John A.; Randall A. Prince (1990). "Anti-Anaerobic Antimicrobial Agents: Cefoxitin, Cefotetan, Clindamycin, and Metronidazole". Texas Heart Institute Journal. 2 17: 77–85.

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1. 嫌気性細菌感染 anaerobic bacterial infections
2. 成人におけるグラム陰性桿菌菌血症 gram negative bacillary bacteremia in adults
3. 細菌検査室におけるグラム染色および培養結果に対するアプローチ approach to gram stain and culture results in the microbiology laboratory
4. グラム陰性桿菌性髄膜炎：治療 gram negative bacillary meningitis treatment
5. 嫌気性感染症における病態生理、臨床的な手がかり、および微生物の回収方法 pathophysiology clinical clues and recovery of organisms in anaerobic infections

English Journal

Lipase-catalyzed esterification of ferulic acid with lauryl alcohol in ionic liquids and antibacterial properties in vitro against three food-related bacteria.

Shi YG1, Wu Y2, Lu XY2, Ren YP3, Wang Q2, Zhu CM2, Yu D2, Wang H4.
Food chemistry.Food Chem.2017 Apr 1;220:249-256. doi: 10.1016/j.foodchem.2016.09.187. Epub 2016 Oct 4.
Lauryl ferulate (LF) was synthesized through lipase-catalyzed esterification of ferulic acid (FA) with lauryl alcohol in a novel ionic liquid ([(EO)-3C-im][NTf2]), and its antibacterial activities was evaluated in vitro against three food-related bacteria. [(EO)-3C-im][NTf2] was first synthesized th
PMID 27855896

Transformation of hexabromocyclododecane in contaminated soil in association with microbial diversity.

Le TT1, Son MH1, Nam IH2, Yoon H1, Kang YG1, Chang YS3.
Journal of hazardous materials.J Hazard Mater.2017 Mar 5;325:82-89. doi: 10.1016/j.jhazmat.2016.11.058. Epub 2016 Nov 21.
This study evaluated the transformation of 1,2,5,6,9,10-hexabromocyclododecane (HBCD) in soil under various conditions. Under anaerobic conditions for 21days, 34% of the total HBCD was reduced from rhizosphere soil containing humic acid, and 35% of the total HBCD was reduced from the non-rhizosphere
PMID 27915102

Designing Solvent Exchange-Induced In Situ Forming Gel from Aqueous Insoluble Polymers as Matrix Base for Periodontitis Treatment.

Srichan T1, Phaechamud T2.
AAPS PharmSciTech.AAPS PharmSciTech.2017 Feb;18(1):194-201. doi: 10.1208/s12249-016-0507-1. Epub 2016 Mar 7.
An in situ forming gel is a dosage form which is promised for site-specific therapy such as periodontal pocket of periodontitis treatment. Ethylcellulose, bleached shellac, and Eudragit RS were applied in this study as a polymeric matrix for in situ forming gel employing N-methyl pyrrolidone (NMP) a
PMID 26951505

Japanese Journal

末梢血液鏡検を契機として早期診断に至った<i>Capnocytophaga canimorsus</i>による掻傷感染症の１例

日本農村医学会雑誌 65(4), 843-849, 2016
NAID 130005286764

Polyphasic characterization of an anaerobic hexachlorobenzene-dechlorinating microbial consortium with a wide dechlorination spectrum for chlorobenzenes(ENVIRONMENTAL BIOTECHNOLOGY)

Journal of bioscience and bioengineering 120(1), 62-68, 2015-07
NAID 110009973287

Prospecting cold deserts of north western Himalayas for microbial diversity and plant growth promoting attributes(ENVIRONMENTAL BIOTECHNOLOGY)

Journal of bioscience and bioengineering 119(6), 683-693, 2015-06
NAID 110009970759

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リンク元	「Gram陰性嫌気性菌」「グラム陰性嫌気性菌」
関連記事	「negative」「anaerobic」「anaerobic bacteria」「gram-negative anaerobic bacteria」