出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2013/01/29 20:16:51」(JST)
Lactobacillus | |
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Lactobacillus near a squamous epithelial cell | |
Scientific classification | |
Phylum: | Firmicutes |
Class: | Bacilli |
Order: | Lactobacillales |
Family: | Lactobacillaceae |
Genus: | Lactobacillus Beijerinck 1901 |
Species | |
L. acetotolerans |
Lactobacillus, also called Döderlein's bacillus, is a genus of Gram-positive facultative anaerobic or microaerophilic rod-shaped bacteria.[1] They are a major part of the lactic acid bacteria group, named as such because most of its members convert lactose and other sugars to lactic acid. In humans they are present in the vagina[2] and the gastrointestinal tract, where they make up a small portion of the gut flora.[3] They are usually benign, except in the mouth where they have been associated with cavities and tooth decay (dental caries). Many species are prominent in decaying plant material. The production of lactic acid makes its environment acidic, which inhibits the growth of some harmful bacteria. Several members of the genus have had their genome sequenced.[4]
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Some Lactobacillus species are used for the production of yogurt, cheese, sauerkraut, pickles, beer, wine, cider, kimchi, cocoa, and other fermented foods, as well as animal feeds, such as silage. Sourdough bread is made using a "starter culture," which is a symbiotic culture of yeast and lactic acid bacteria growing in a water and flour medium. Lactobacilli, especially L. casei and L. brevis, are some of the most common beer spoilage organisms. The species operate by lowering the pH of the fermenting substance by creating the lactic acid, neutralising it to the desired extent.
Some strains of Lactobacillus spp. and other lactic acid bacteria may possess potential therapeutic properties including anti-inflammatory and anti-cancer activities, as well as other features of interest. A study by researchers from the Beth Israel Deaconess Medical Center and UCLA in 2009 demonstrated the protective effects of some strains of these bacteria for anti-tumor and anti-cancer effects in mice.[5] Dietary administration alleviated the risks of certain types of cancers and suppressed colonic tumor incidence, volume and multiplicity induced by various carcinogens. For a few strains oral administration effectively reduced DNA adduct formation, ameliorated DNA damage and prevented putative preneoplastic lesions such as aberrant crypt foci induced by chemical carcinogens in the gastrointestinal tract. Reports also indicated that some cultures administered to animals inhibited liver, colon, bladder, and mammary tumors, highlighting potential systemic effects of probiotics with anti-neoplastic activities.[4]
Lactobacilli can also be used to restore particular physiological balance such as in the vaginal eco-system.[6][7][8] Their role is (1) to physically protect the vaginal epithelium by building a thick layer separating the epithelium from pathogens, (2) to physiologically keep the balance of the vaginal ecosystem in maintaining the pH at ~4.5, and (3) generating hydrogen peroxide against pathogens. Lactobacilli are highly tolerant to low pH and can easily maintain low pH and protect the vaginal eco-system from Gram-negative and Gram-positive bacteria.
The genus Lactobacillus currently consists of over 180 species and encompasses a wide variety of organisms.[9] The genus is polyphyletic, with the genus Pediococcus dividing the L. casei group, and the species L. acidophilus, L. salivarius, and L. reuteri being representatives of three distinct subclades. The genus Paralactobacillus falls within the L. salivarius group. In recent years, other members of the genus Lactobacillus (formerly known as the Leuconostoc branch of Lactobacillus) have been reclassified into the genera Atopobium, Carnobacterium, Weissella, Oenococcus, and Leuconostoc. More recently, the Pediococcus species P. dextrinicus has been reclassified as a Lactobacillus species (IJSEM, Paper in Press).
While streptococci family bacteria (e.g. Streptococcus mutans) are the main cause of tooth decay, other varieties of microbes can cause dental caries, but to a lesser extent. For example, although considered beneficial, some Lactobacillus species have been associated with dental caries. The Lactobacillus count in saliva has been used as a "caries test" for many years. This is one of the arguments used in support of the use of fluoride in toothpaste. Lactobacilli characteristically cause existing carious lesions to progress, especially those in coronal caries. The issue is, however, complex as recent studies show probiotics can allow beneficial Lactobacilli to populate sites on teeth, preventing streptococci pathogens from taking hold and inducing dental decay.[1]
Many lactobacilli are unusual in that they operate using homofermentative metabolism (that is, they produce only lactic acid from sugars in contrast to heterofermentative lactobacilli which can produce either alcohol or lactic acid from sugars) and are aerotolerant despite the complete absence of a respiratory chain[citation needed]. This aerotolerance is manganese-dependent and has been explored (and explained) in Lactobacillus plantarum. Many lactobacilli do not require iron for growth and have an extremely high hydrogen peroxide tolerance.
According to metabolism, Lactobacillus species can be divided into three groups:
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リンク元 | 「細菌の鑑別」「齲蝕」「ラクトバチルス属」「乳酸桿菌属」「乳酸菌類」 |
拡張検索 | 「Lactobacillus fermentum」「Lactobacillus reuteri」「Lactobacillus casei」「Lactobacillus helveticus」「Lactobacillus brevis」 |
菌種 | 形態 | 抗酸性 | 芽胞 | 運動性 | 空気中での発育 | 嫌気条件下での発育 | カタラーゼ | オキシダーゼ | ブドウ糖分解 | OF試験 |
Micrococcus | C | - | - | - | + | - | + | - | D | O/- |
Staphylococcus | C | - | - | - | + | + | + | - | + | F |
Aerococcus | C | - | - | - | + | W | W/- | - | + | F |
Streptococcus | C | - | - | +/- | + | + | - | - | + | F |
Pediococcus | C. | - | - | - | + | + | - | - | + | F |
Gemella | ||||||||||
嫌気性球菌*1 | C | - | - | - | - | + | - | - | +/- | F/- |
Kurthia | R | - | - | + | + | + | + | - | - | - |
Corynebacterium | R | - | - | - | + | + | + | - | +/- | F/- |
Listeria | R | - | - | + | + | + | + | - | + | F |
Erysipelothnx | R | - | - | + | + | + | F | |||
Lactobacillus | ||||||||||
Arachnia*2 | ||||||||||
Rothia | R | - | - | - | + | - | + | ● | + | F |
Propiombacterium | R | - | - | - | - | + | + | . | + | F |
Achnomyces | R | - | - | - | - | + | - | ● | + | F |
Bifidobacterium | ||||||||||
Eubacterium | R | - | - | - | - | + | - | . | +/- | F/- |
Clostridium | R | - | <+> | D | - | + | - | ● | D | F/- |
Bacillus | R | - | <+> | D | + | D | + | d | D | F/O/- |
Nocardia | R | W | - | - | + | - | + | - | + | O |
Mycobacterium | R | + | - | - | + | . | + | - | + | O/NT |
*1:Peptococcus, Peptostreptococus(あるいは Leuconostoc) *2:あるいはActinomyces odontolyticus D:その属の菌種によって反応が異なる。 d: 菌種によって反応が異なる。 F:発酵 O:酸化 W:弱反応 ・:不明 NT:テストできない <+>:芽胞非形成筋もある C:球菌 R:桿菌 |
菌種 | 形態 | 運動性 | 空気中での発育 | 嫌気条件下での発育 | カタラーゼ | オキシダーゼ | ブドウ糖(酸) | OF試験 |
Bacteroides | R | - | - | + | d | - | D | F/- |
Veillonella | C | - | - | + | D | ・ | - | - |
Neissena | C | - | + | - | + | + | + | O |
Branhamella | C | - | + | - | + | + | - | - |
Acinetobacter | C/R | - | + | - | + | - | + | O |
Moraxella | R | - | + | + | + | - | ||
Brucella | ||||||||
Bordetella | ||||||||
Chromobacterium lividum | R | + | + | - | + | + | + | O |
Alcahsenes | R | + | + | - | + | + | - | - |
Flavobacterium | R | - | + | - | + | + | + | O |
Pseudomonas | R | + | + | + | + | + | + | O |
Actinobacillus | R | - | + | + | + | + | + | F |
Pasteurella | ||||||||
Necromonas | ||||||||
Cardiobacterium | R | - | + | + | - | + | + | F |
Chromobacterium violaceum | ||||||||
Beneckea | R | + | + | + | + | + | + | F |
Vibrio | ||||||||
Plesiomonas | ||||||||
Aeromonas | ||||||||
腸内細菌 | R | D | + | + | + | - | + | F |
Haemophilus | R | - | + | + | D | - | D | NT |
Eikenella | R | - | -* | + | - | + | - | - |
Campylobacter | R | + | -+1 | - | D | + | - | - |
Streptobacillus+2 | R | - | + | + | - | - | + | F |
マイコプラズマ | ||||||||
*1:Peptococcus, Peptostreptococus(あるいは Leuconostoc) *2:あるいはActinomyces odontolyticus D:その属の菌種によって反応が異なる。 d: 菌種によって反応が異なる。 F:発酵 O:酸化 W:弱反応 ・:不明 NT:テストできない <+>:芽胞非形成筋もある C:球菌 R:桿菌 ・: 不明 *: 空気中では発育せず。空気CO2で発育。+1: 好気的または嫌気的には発育せず。5-6%O2中で発育。+2: あるいはShigella dysenteriae 1 |
グラム染色性 | 病原菌名 | |
グラム陽性球菌 | 連鎖球菌 | Streptococcus mutans |
Streptococcus salivarius | ||
Streptococcus sangius | ||
Streptococcus mitis | ||
グラム陽性桿菌 | 放線菌 | Actinomyces viscosus |
グラム陰性桿菌 | 乳酸桿菌 | Lactobacillus |
ファーメンタム菌、発酵乳酸桿菌、発酵乳酸杆菌、ラクトバチルス・ファーメンタム
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