Characteristics of a nitropropanol-metabolizing bacterium isolated from the rumen.
We report some characteristics of a ruminal bacterium (strain NPOH1) that metabolizes 3-nitropropanol, the toxic principle of various milk vetchs that are distributed worldwide. The gram-positive bacterium was nonmotile and did not produce spores. Growth of strain NPOH1 occurred under anaerobic conditions and was supported by the electron acceptors 3-nitropropanol, 3-nitropropionate, nitrate, 2-nitropropanol, nitroethane, nitroethanol, or 3-nitro-1-propyl-beta-D-glucopyranoside (miserotoxin). Other potential electron acceptors, namely sulfate, sulfite, azide, chlorate, perchlorate, nitrite, fumarate, 2-nitrobutane, or nitrobenzene, did not support growth. Formate, lactate, and H2 stimulated growth of strain NPOH1 in the presence of the appropriate nitrocompound, whereas a variety of other potential H2 donors did not. When grown in medium containing both nitrate and either 3-nitropropanol or 3-nitropropionate, nitrate was the preferred acceptor. Strain NPOH1 reduced nitrate to nitrite and, when grown with excess reductant, nitrite was further reduced to ammonia. The products formed during the metabolism of 3-nitropropanol and 3-nitropropionate by mixed ruminal populations, 3-aminopropanol and beta-alanine, were not found in culture fluids of strain NPOH1. Analysis of total cellular fatty acid profiles and of the mole percent guanine plus cytosine suggests that strain NPOH1 is a novel bacterium. The capacity of strain NPOH1 to metabolize 3-nitropropanol suggests that this organism may play an important role in detoxification of 3-nitropropanol in the rumen.
Anderson
R C
RC
National Animal Disease Center, U.S. Department of Agriculture, Agricultural Research Service, Ames, IA 50010, USA.
Rasmussen
M A
MA
DiSpirito
A A
AA
Allison
M J
MJ
D000818:Animals; D015373:Bacterial Typing Techniques; D001673:Biodegradation, Environmental; D002417:Cattle; D004269:DNA, Bacterial / Q000737:chemistry; D005227:Fatty Acids / Q000032:analysis; D006093:Gram-Positive Asporogenous Rods / Q000502:physiology*; D009574:Nitro Compounds; D016877:Oxidants / Q000378:metabolism; D011042:Poisons / Q000378:metabolism*; D011422:Propionates / Q000378:metabolism*; D012417:Rumen / Q000382:microbiology*
D004269:DNA, Bacterial; D005227:Fatty Acids; D009574:Nitro Compounds; D016877:Oxidants; D011042:Poisons; D011422:Propionates; C015392:3-nitropropionic acid