Location
University of Nevada Las Vegas, Student Union Ball Room
Start Date
6-8-2008 9:00 AM
End Date
6-8-2008 12:00 PM
Description
Magnetotactic bacteria is the categorical name for a group of prokaryotes that biomineralize magnetosomes which are intracellular, membrane-bounded magnetic iron mineral crystals. The focus of this study is on two magnetiteproducing, magnetotactic sulfate-reducing bacteria (SRB), Desulfovibrio magneticus strain RS-1 and strain FH-1 which also belongs in the genus Desulfovibrio in the δ-Proteobacteria. SRB utilize sulfate as a terminal electron acceptor under anaerobic conditions reducing sulfate to sulfide. A large number of organic compounds as well as some inorganic compounds have been shown to provide electrons for sulfate reduction. Traditionally, because no SRB have been shown to convincingly grow with O2 as a terminal electron acceptor, they have been classified as obligate anaerobes.
In characterizing several magnetotactic SRB, we found that cells of D. magneticus and strain FH-1 utilized O2 as an electron acceptor for growth. To prove this we grew cells of both strains in several different semi-solid growth media under air or N2 gas. Cells of both strains grew as a microaerophilic band of cells at the oxic-anoxic interface (OAI) in media under air lacking sulfate (medium contained cysteine or cysteine with either Casamino Acids or Yeast Extract as a sulfur source). Sulfide (as FeS: high [Fe] was used as a trap for sulfide) was not produced in these tubes. Cells did not grow under anaerobic conditions (under N2) in this medium unless sulfate was present. When sulfate was present in the growth medium, under air, initial growth of the strains was also as a microaerophilic band of cells at the OAI. However as time went on, the band of D. magneticus split into two. The band of FH-1 cells did not split into two bands and moved up the tube almost to the meniscus. The medium also turned dark indicating sulfide production. The results show that these magnetotactic SRB strains are capable of aerobic growth with O2 as a terminal electron acceptor.
Keywords
Anaerobes; Anaerobic bacteria; Desulfovibrio magneticus; Magnetotactic sulfate-reducing bacteria; Anaerobes; Oxygen; Prokaryotes; Sulfates; Sulfides
Disciplines
Bacteriology
Language
English
Aerobic respiration by two Sulfate reducing magnetotactic bacteria, strains RS-1 and FH-1
University of Nevada Las Vegas, Student Union Ball Room
Magnetotactic bacteria is the categorical name for a group of prokaryotes that biomineralize magnetosomes which are intracellular, membrane-bounded magnetic iron mineral crystals. The focus of this study is on two magnetiteproducing, magnetotactic sulfate-reducing bacteria (SRB), Desulfovibrio magneticus strain RS-1 and strain FH-1 which also belongs in the genus Desulfovibrio in the δ-Proteobacteria. SRB utilize sulfate as a terminal electron acceptor under anaerobic conditions reducing sulfate to sulfide. A large number of organic compounds as well as some inorganic compounds have been shown to provide electrons for sulfate reduction. Traditionally, because no SRB have been shown to convincingly grow with O2 as a terminal electron acceptor, they have been classified as obligate anaerobes.
In characterizing several magnetotactic SRB, we found that cells of D. magneticus and strain FH-1 utilized O2 as an electron acceptor for growth. To prove this we grew cells of both strains in several different semi-solid growth media under air or N2 gas. Cells of both strains grew as a microaerophilic band of cells at the oxic-anoxic interface (OAI) in media under air lacking sulfate (medium contained cysteine or cysteine with either Casamino Acids or Yeast Extract as a sulfur source). Sulfide (as FeS: high [Fe] was used as a trap for sulfide) was not produced in these tubes. Cells did not grow under anaerobic conditions (under N2) in this medium unless sulfate was present. When sulfate was present in the growth medium, under air, initial growth of the strains was also as a microaerophilic band of cells at the OAI. However as time went on, the band of D. magneticus split into two. The band of FH-1 cells did not split into two bands and moved up the tube almost to the meniscus. The medium also turned dark indicating sulfide production. The results show that these magnetotactic SRB strains are capable of aerobic growth with O2 as a terminal electron acceptor.
Comments
Abstract & poster