Feasibility of /sup 55/Fe autoradiography as performed on N/sub 2/-fixing Anabaena spp. populations and associated bacteria

Journal Article · Fri Jan 01 04:00:00 EST 1982 · Appl. Environ. Microbiol.; (United States)

OSTI ID:5503811

Paerl, H W

/sup 55/Fe emits low-energy X rays and Auger electrons by electron capture decay. Auger electrons are useful for autoradiographic examination of /sup 55/Fe incorporation among microbial communities. Attainable resolution, in terms of silver grain deposition, is excellent and comparable to /sup 3/H. Two known Fe-demanding processes, photosynthetic CO/sub 2/ fixation and N/sub 2/ fixation, were examined by autoradiography of Anabaena populations. During photosynthetically active (illuminated) N/sub 2/-fixing periods, biological incorporation of /sup 55/FeCl/sub 3/ by vegetative cells and heterocysts was evident. When N/sub 2/ fixation was suppressed by NH/sub 4//sup +/ additions, heterocysts revaled no incorporation of /sup 55/Fe. Conversely, when N/sub 2/-fixing Anabaena filaments were placed in darkness, /sup 55/Fe incorporation decreased in vegetative cells, whereas heterocysts showed sustained rates of /sup 55/Fe incorporation. Bacteria actively incorporated /sup 55/Fe under both light and dark conditions. The chelated (by Na/sub 2/-ethylenediaminetetraacetate) form of /sup 55/FeCl/sub 3/ was more readily incorporated than the nonchelated form. Furthermore, abiotic adsorption of /sup 55/Fe to filters and nonliving particles proved lower when chelated /sup 55/Fe was used in experiments. /sup 55/Fe autoradiography is useful for observing the fate and cellular distribution of various forms of Fe among aquatic microbial communities.

• Research Organization: Univ. of North Carolina, Morehead, NC
• OSTI ID: 5503811
• Journal Information: Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 43:1; ISSN AEMID
• Country of Publication: United States
• Language: English

Related Subjects

550201 -- Biochemistry-- Tracer Techniques
550701* -- Microbiology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALGAE
AQUATIC ECOSYSTEMS
AUGER ELECTRON SPECTROSCOPY
AUTORADIOGRAPHY
BACTERIA
BETA DECAY RADIOISOTOPES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHLORIDES
CHLORINE COMPOUNDS
COMPARATIVE EVALUATIONS
ECOSYSTEMS
ELECTROMAGNETIC RADIATION
ELECTRON CAPTURE RADIOISOTOPES
ELECTRON SPECTROSCOPY
EVEN-ODD NUCLEI
FEASIBILITY STUDIES
HALIDES
HALOGEN COMPOUNDS
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
IRON 55
IRON CHLORIDES
IRON COMPOUNDS
IRON ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
MICROORGANISMS
NITROGEN FIXATION
NUCLEI
OXIDES
OXYGEN COMPOUNDS
PLANTS
RADIATIONS
RADIOISOTOPES
SPECTROSCOPY
TRACER TECHNIQUES
TRANSITION ELEMENT COMPOUNDS
TRITIUM COMPOUNDS
X RADIATION
YEARS LIVING RADIOISOTOPES