Isolation and characterization of novel iron-oxidizing bacteria that grow at circumneutral pH
A gel-stabilized gradient method that employed opposing gradients of Fe2+ and O2 was used to isolate and characterize two new Fe-oxidizing bacteria from a neutral pH, Fe(2+)-containing groundwater in Michigan. Two separate enrichment cultures were obtained, and in each the cells grew in a distinct,...
Published in: | Applied and Environmental Microbiology |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
American Society for Microbiology
1997
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1128/aem.63.12.4784-4792.1997 https://journals.asm.org/doi/pdf/10.1128/aem.63.12.4784-4792.1997 |
id |
crasmicro:10.1128/aem.63.12.4784-4792.1997 |
---|---|
record_format |
openpolar |
spelling |
crasmicro:10.1128/aem.63.12.4784-4792.1997 2024-06-23T07:56:09+00:00 Isolation and characterization of novel iron-oxidizing bacteria that grow at circumneutral pH Emerson, D Moyer, C 1997 http://dx.doi.org/10.1128/aem.63.12.4784-4792.1997 https://journals.asm.org/doi/pdf/10.1128/aem.63.12.4784-4792.1997 en eng American Society for Microbiology https://journals.asm.org/non-commercial-tdm-license Applied and Environmental Microbiology volume 63, issue 12, page 4784-4792 ISSN 0099-2240 1098-5336 journal-article 1997 crasmicro https://doi.org/10.1128/aem.63.12.4784-4792.1997 2024-06-10T04:07:02Z A gel-stabilized gradient method that employed opposing gradients of Fe2+ and O2 was used to isolate and characterize two new Fe-oxidizing bacteria from a neutral pH, Fe(2+)-containing groundwater in Michigan. Two separate enrichment cultures were obtained, and in each the cells grew in a distinct, rust-colored band in the gel at the oxic-anoxic interface. The cells were tightly associated with the ferric hydroxides. Repeated serial dilutions of both enrichments resulted in the isolation of two axenic strains, ES-1 and ES-2. The cultures were judged pure based on (i) growth from single colonies in tubes at dilutions of 10(-7) (ES-2) (ES-2) and 10(-8) (ES-1); (ii) uniform cell morphologies, i.e., ES-1 was a motile long thin, bent, or S-shaped rod and ES-2 was a shorter curved rod; and (iii) no growth on a heterotrophic medium. Strain ES-1 grew to a density of 10(8) cells/ml on FeS with a doubling time of 8 h. Strain ES-2 grew to a density of 5 x 10(7) cells/ml with a doubling time of 12.5 h. Both strains also grew on FeCO3. Neither strain grew without Fe2+, nor did they grow with glucose, pyruvate, acetate, Mn, or H2S as an electron donor. Studies with an oxygen microelectrode revealed that both strains grew at the oxic-anoxic interface of the gradients and tracked the O2 minima when subjected to higher O2 concentrations, suggesting they are microaerobes. Phylogenetically the two strains formed a novel lineage within the gamma Proteobacteria. They were very closely related to each other and were equally closely related to PVB OTU 1, a phylotype obtained from an iron-rich hydrothermal vent system at the Loihi Seamount in the Pacific Ocean, and SPB OTU 1, a phylotype obtained from permafrost soil in Siberia. Their closest cultivated relative was Stenotrophomonas maltophilia. In total, this evidence suggests ES-1 and ES-2 are members of a previously untapped group of putatively lithotrophic, unicellular iron-oxidizing bacteria. Article in Journal/Newspaper permafrost Siberia ASM Journals (American Society for Microbiology) Pacific Applied and Environmental Microbiology 63 12 4784 4792 |
institution |
Open Polar |
collection |
ASM Journals (American Society for Microbiology) |
op_collection_id |
crasmicro |
language |
English |
description |
A gel-stabilized gradient method that employed opposing gradients of Fe2+ and O2 was used to isolate and characterize two new Fe-oxidizing bacteria from a neutral pH, Fe(2+)-containing groundwater in Michigan. Two separate enrichment cultures were obtained, and in each the cells grew in a distinct, rust-colored band in the gel at the oxic-anoxic interface. The cells were tightly associated with the ferric hydroxides. Repeated serial dilutions of both enrichments resulted in the isolation of two axenic strains, ES-1 and ES-2. The cultures were judged pure based on (i) growth from single colonies in tubes at dilutions of 10(-7) (ES-2) (ES-2) and 10(-8) (ES-1); (ii) uniform cell morphologies, i.e., ES-1 was a motile long thin, bent, or S-shaped rod and ES-2 was a shorter curved rod; and (iii) no growth on a heterotrophic medium. Strain ES-1 grew to a density of 10(8) cells/ml on FeS with a doubling time of 8 h. Strain ES-2 grew to a density of 5 x 10(7) cells/ml with a doubling time of 12.5 h. Both strains also grew on FeCO3. Neither strain grew without Fe2+, nor did they grow with glucose, pyruvate, acetate, Mn, or H2S as an electron donor. Studies with an oxygen microelectrode revealed that both strains grew at the oxic-anoxic interface of the gradients and tracked the O2 minima when subjected to higher O2 concentrations, suggesting they are microaerobes. Phylogenetically the two strains formed a novel lineage within the gamma Proteobacteria. They were very closely related to each other and were equally closely related to PVB OTU 1, a phylotype obtained from an iron-rich hydrothermal vent system at the Loihi Seamount in the Pacific Ocean, and SPB OTU 1, a phylotype obtained from permafrost soil in Siberia. Their closest cultivated relative was Stenotrophomonas maltophilia. In total, this evidence suggests ES-1 and ES-2 are members of a previously untapped group of putatively lithotrophic, unicellular iron-oxidizing bacteria. |
format |
Article in Journal/Newspaper |
author |
Emerson, D Moyer, C |
spellingShingle |
Emerson, D Moyer, C Isolation and characterization of novel iron-oxidizing bacteria that grow at circumneutral pH |
author_facet |
Emerson, D Moyer, C |
author_sort |
Emerson, D |
title |
Isolation and characterization of novel iron-oxidizing bacteria that grow at circumneutral pH |
title_short |
Isolation and characterization of novel iron-oxidizing bacteria that grow at circumneutral pH |
title_full |
Isolation and characterization of novel iron-oxidizing bacteria that grow at circumneutral pH |
title_fullStr |
Isolation and characterization of novel iron-oxidizing bacteria that grow at circumneutral pH |
title_full_unstemmed |
Isolation and characterization of novel iron-oxidizing bacteria that grow at circumneutral pH |
title_sort |
isolation and characterization of novel iron-oxidizing bacteria that grow at circumneutral ph |
publisher |
American Society for Microbiology |
publishDate |
1997 |
url |
http://dx.doi.org/10.1128/aem.63.12.4784-4792.1997 https://journals.asm.org/doi/pdf/10.1128/aem.63.12.4784-4792.1997 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
permafrost Siberia |
genre_facet |
permafrost Siberia |
op_source |
Applied and Environmental Microbiology volume 63, issue 12, page 4784-4792 ISSN 0099-2240 1098-5336 |
op_rights |
https://journals.asm.org/non-commercial-tdm-license |
op_doi |
https://doi.org/10.1128/aem.63.12.4784-4792.1997 |
container_title |
Applied and Environmental Microbiology |
container_volume |
63 |
container_issue |
12 |
container_start_page |
4784 |
op_container_end_page |
4792 |
_version_ |
1802649066058809344 |