Horn Marcus A, Ihssen Julian, Matthies Carola, Schramm Andreas, Acker Georg, Drake Harold L
Department of Ecological Microbiology, University of Bayreuth, 95440 Bayreuth, Germany.
Electron Microscopy Laboratory, University of Bayreuth, 95440 Bayreuth, Germany.
Int J Syst Evol Microbiol. 2005 May;55(Pt 3):1255-1265. doi: 10.1099/ijs.0.63484-0.
Earthworms emit nitrous oxide (N(2)O) via the activity of bacteria in their gut. Four N(2)O-producing facultative aerobes, ED1(T), ED5(T), MH21(T) and MH72, were isolated from the gut of the earthworm Aporrectodea caliginosa. The isolates produced N(2)O under conditions that simulated the microenvironment of the earthworm gut. ED1(T) and ED5(T) were Gram-negative, motile rods that carried out complete denitrification (i.e. the reduction of nitrate to N(2)) and contained membranous c-type cytochromes. ED1(T) grew optimally at 30 degrees C and pH 7. ED1(T) oxidized organic acids and reduced (per)chlorate, sulfate, nitrate and nitrite. The closest phylogenetic relative of ED1(T) was Dechloromonas agitata. ED5(T) grew optimally at 25 degrees C and pH 7. ED5(T) grew mainly on sugars, and nitrate and nitrite were used as alternative electron acceptors. The closest phylogenetic relatives of ED5(T) were Flavobacterium johnsoniae and Flavobacterium flevense. MH21(T) and MH72 were motile, spore-forming, rod-shaped bacteria with a three-layered cell wall. Sugars supported the growth of MH21(T) and MH72. Cells of MH21(T) grew in chains, were linked by connecting filaments and contained membranous b-type cytochromes. MH21(T) grew optimally at 30-35 degrees C and pH 7.7, grew by fermentation and reduced low amounts of nitrite to N(2)O. The closest phylogenetic relatives of MH21(T) were Paenibacillus borealis and Paenibacillus chibensis. Based on morphological, physiological and phylogenetic characteristics, ED1(T) (= DSM 15892(T) = ATCC BAA-841(T)), ED5(T) (= DSM 15936(T) = ATCC BAA-842(T)) and MH21(T) (=DSM 15890(T) = ATCC BAA-844(T)) are proposed as type strains of the novel species Dechloromonas denitrificans sp. nov., Flavobacterium denitrificans sp. nov. and Paenibacillus anaericanus sp. nov., respectively. MH72 is considered a new strain of Paenibacillus terrae.
蚯蚓通过其肠道内细菌的活动排放一氧化二氮（N₂O）。从蚯蚓暗色无腔蚓的肠道中分离出四种产N₂O的兼性需氧菌，ED1(T)、ED5(T)、MH21(T)和MH72。这些分离菌株在模拟蚯蚓肠道微环境的条件下产生N₂O。ED1(T)和ED5(T)是革兰氏阴性、能运动的杆菌，进行完全反硝化作用（即将硝酸盐还原为N₂），并含有膜结合c型细胞色素。ED1(T)在30℃和pH 7条件下生长最佳。ED1(T)能氧化有机酸，并能还原高氯酸盐、硫酸盐、硝酸盐和亚硝酸盐。ED1(T)最相近的系统发育亲缘菌是激动脱氯单胞菌。ED5(T)在25℃和pH 7条件下生长最佳。ED5(T)主要利用糖类生长，硝酸盐和亚硝酸盐用作替代电子受体。ED5(T)最相近的系统发育亲缘菌是约翰逊黄杆菌和弗勒沃黄杆菌。MH21(T)和MH72是能运动、产芽孢的杆状细菌，具有三层细胞壁。糖类支持MH21(T)和MH72的生长。MH21(T)的细胞成链生长，通过连接丝相连，并含有膜结合b型细胞色素。MH21(T)在30 - 35℃和pH 7.7条件下生长最佳，通过发酵生长，并将少量亚硝酸盐还原为N₂O。MH21(T)最相近的系统发育亲缘菌是北方类芽孢杆菌和千曲类芽孢杆菌。基于形态、生理和系统发育特征，分别将ED1(T)（= DSM 15892(T) = ATCC BAA - 841(T)）、ED5(T)（= DSM 15936(T) = ATCC BAA - 842(T)）和MH21(T)（=DSM 15890(T) = ATCC BAA - 844(T)）提议为新种反硝化脱氯单胞菌、反硝化黄杆菌和厌氧类芽孢杆菌的模式菌株。MH72被认为是土壤类芽孢杆菌的一个新菌株。
