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Any of various bacteria, especially those of the genus Rhizobium, that carry out nitrogen fixation in the root nodules of leguminous plants and often change markedly in size and shape after they enter the roots.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(ˈbæktəˌrɔɪd) or


(Microbiology) resembling a bacterium
(Microbiology) any rodlike bacterium of the genus Bacteroides, occurring in the gut of humans and animals
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈbæk təˌrɔɪd)
1. any of the rod-shaped or branched bacteria in the root nodules of nitrogen-fixing plants.
2. Also, bac`te•roi′dal. resembling bacteria.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.bacteroid - a rodlike bacterium (especially any of the rod-shaped or branched bacteria in the root nodules of nitrogen-fixing plants)bacteroid - a rodlike bacterium (especially any of the rod-shaped or branched bacteria in the root nodules of nitrogen-fixing plants)
bacteria, bacterium - (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
Adj.1.bacteroid - resembling bacteriabacteroid - resembling bacteria      
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
Indirect evidence for cellulase production by Rhizobium in pea root nodules during bacteroid differentiation: cytochemical aspects of cellulose breakdown in rhizobial droplets.
Mutans, Gram -ve cocci like Neisseria, Gram +ve rods like Actinomyces Israeli, Corynebacterium, Gram -ve rods like Bacteroid Melanogenicus, Bacteroid Intermedius, Spirochetes like Treponema Microdentium, Treponema Ovale.
Now there are some data about links of the outer bacteroid membrane with regions of the peribacteroid membrane (PBM) that can serve as a proof that physical contact between the bacterial surface and the membrane of the plant cell is a factor without which it is impossible to establish normal symbiosis [10].
Decreased SNA may also be due to the effect of heavy metal ions on [O.sub.2] uptake by bacteroid which could result in inhibition of acetylene reduction activity.
There are sequence of events that are necessary for symbiotic nitrogen fixation which includes preinfection, root colonization, root adhesion, hair branching, hair curling, infection, nodule initiation, bacterial release, bacteroid development, nodule function, nitrogen fixation, complementary functions, and nodule persistence [3].
Importance of bacteroid number in nodules and effective nodule mass to dinitrogen fixation by cowpeas.
Bacteroid oxalate oxidase and soluble oxalate in nodules of faba beans (Viciafaba L.) submitted to water restricted conditions: Possible involvement in nitrogen fixation.
Commonly, organisms cultured from deep neck space infections are ss-haemolytic Streptococcus, Staphy-lococcus aureus, Bacteroides and Neisseria species.8 The predominant anaerobes include Fusobacterium nucleatum, Bacteroid melaninogenicus and Peptostreptococcus.9 A culture of Klebsiella pneumoniae in parapharyngeal abscess is a rare entity.
"The bacteroid [symbiotic bacterium] seems to be telling the plant to turn up the [ALA-making] activity."
Inhibition of growth of Bradyrhizobium japonicum bacteroid by spermidine and spermine in yeast extract.
Bacteroids, according to Bien, form when a patient has colitis and colon cancer.