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Title: Autoradiographic method to screen for soil microorganisms which accumulate zinc

Journal Article · · Appl. Environ. Microbiol.; (United States)
OSTI ID:5662859

An autoradiographic method was developed to screen for and isolate soil microorganisms which accumulate zinc (ZN). Diluted soil samples (pH 5.9) were plated on soil extract-glucose agar containing radioactive /sup 65/Zn. After 7 days of incubation, individual colonies which accumulated sufficient /sup 65/Zn could be detected by autoradiography. These colonies were isolated and confirmed as Zn accumulators in pure culture by using the autoradiographic plate technique. Most Zn accumulators were filamentous fungi, identified as Penicillium janthinellum, Aspergillus fumigatus, and Paecilomyces sp. Isolates of Penicillium janthinellum were the most common Zn accumulators. The most abundant Zn-accumulating bacteria were Bacillus spp. The validity of the autoradiographic plate technique to differentiate soil microbes which accumulate Zn was examined independently by energy dispersive X-ray analysis in a scanning electron microscope. This method confirmed that fungal isolates which gave positive autoradiographic responses in the plate assay bioaccumulated more Zn in their biomass than fungal isolates from the same soil sample which gave negative autoradiographic responses. Thus, this technique can be applied to specifically screen for and isolate microbes from the environment which bioaccumulate Zn.

Research Organization:
Michigan State Univ., East Lansing
OSTI ID:
5662859
Journal Information:
Appl. Environ. Microbiol.; (United States), Vol. 49:1
Country of Publication:
United States
Language:
English