Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2010-6-25
pubmed:abstractText
The nitrogen-deficient coastal waters of North Carolina contain suspended bacteria potentially able to fix N(2). Bioassays aimed at identifying environmental factors controlling the development and proliferation of N(2) fixation showed that dissolved organic carbon (as simple sugars and sugar alcohols) and particulate organic carbon (derived from Spartina alterniflora) additions elicited and enhanced N(2) fixation (nitrogenase activity) in these waters. Nitrogenase activity occurred in samples containing flocculent, mucilage-covered bacterial aggregates. Cyanobacterium-bacterium aggregates also revealed N(2) fixation. In all cases bacterial N(2) fixation occurred in association with surficial microenvironments or microzones. Since nitrogenase is oxygen labile, we hypothesized that the aggregates themselves protected their constituent microbes from O(2). Microelectrode O(2) profiles revealed that aggregates had lower internal O(2) tensions than surrounding waters. Tetrazolium salt (2,3,5-triphenyl-3-tetrazolium chloride) reduction revealed that patchy zones existed both within microbes and extracellularly in the mucilage surrounding microbes where free O(2) was excluded. Triphenyltetrazolium chloride reduction also strongly inhibited nitrogenase activity. These findings suggest that N(2) fixation is mediated by the availability of the appropriate types of reduced microzones. Organic carbon enrichment appears to serve as an energy and structural source for aggregate formation, both of which were required for eliciting N(2) fixation responses of these waters.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-1257749, http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-14448610, http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-16345217, http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-16345379, http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-16345923, http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-16346241, http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-16346855, http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-17740970, http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-17769213, http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-4621614, http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-4981122, http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-5237501, http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-5797517, http://linkedlifedata.com/resource/pubmed/commentcorrection/16347337-6776883
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
May
pubmed:issn
0099-2240
pubmed:author
pubmed:issnType
Print
pubmed:volume
53
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1078-87
pubmed:dateRevised
2010-9-20
pubmed:year
1987
pubmed:articleTitle
Oxygen-poor microzones as potential sites of microbial n(2) fixation in nitrogen-depleted aerobic marine waters.
pubmed:affiliation
Institute of Marine Sciences, University of North Carolina, Morehead City, North Carolina 28557.
pubmed:publicationType
Journal Article