PMID- 16333749
OWN - NLM
STAT- MEDLINE
DCOM- 20060425
LR  - 20131121
IS  - 0966-0844 (Print)
IS  - 0966-0844 (Linking)
VI  - 18
IP  - 5
DP  - 2005 Oct
TI  - Manganese oxidation by bacterial isolates from the Indian ridge system.
PG  - 483-92
AB  - The abundance and activity of culturable manganese-oxidizing bacteria were 
      assessed from near-bottom water samples of the tectonically active Carlsberg 
      Ridge. Retrievable counts as colony forming units (CFU) on dilute nutrient agar 
      medium (dilNA=2 gm l(-1) nutrient broth+2% agar) and on dilNA supplemented with 
      1, 2 and 3 mM MnCl(2).4H(2)O were in the order of 10(6) CFU l(-1). Retrievability 
      of heterotrophs ranged from non-detectable levels (ND) to 2.82 x 10(6) CFU l(-1). 
      The retrievable counts on Mn amended dilNA ranged from ND to 3.21 x 10(6), 1.47 x 
      10(6) and 1.45 x 10(6) CFU l(-1) on 1, 2 and 3 mM, respectively. About 87% of the 
      Mn tolerant isolates (n=39) showed taxonomic affinities to Pseudomonas I and II 
      sp. Two representative strains CR35 and CR48 (CR-Carlsberg Ridge) isolated on 
      manganese-supplemented media were tested for their ability to tolerate a range of 
      Mn amendments from 1 nM to 100 mM in terms of growth and respiration. CR35 
      represents 66% of the total CFU (3.04 x 10(6) CFU l(-1)), while CR48 represented 
      only 6% of the total CFU (1.05 x 10(6) CFU l(-1)). The colonies of these two 
      isolates were dark brown in color suggesting precipitation of Mn as oxide. Tests 
      for the effect on growth and respiration were conducted in media simulating 
      heterotrophic (amended with 0.01% glucose) and lithotrophic (unamended) 
      conditions. Maximum stimulation in growth and respiration of CR35 occurred at 100 
      microM Mn both in unamended and amended media. At levels of Mn greater than 100 
      microM the counts decreased steadily. Total respiring cells of CR48 were 
      stimulated to a maximum at 1 microM Mn in unamended medium and 1 nM in amended 
      medium. Total cells counts for the same decreased beyond 100 microM Mn in 
      unamended and 1 nM in amended medium. The isolates were tested for their ability 
      to oxidize Mn amendments from 1 microM to 10 mM Mn. At the end of a 76-day 
      incubation period, there was evidence of manganese oxide precipitation at high Mn 
      concentrations (>or=1 mM) as a dark brown coloration on the sides of culture 
      tubes. Highest Mn oxidation rates were observed at 10 mM Mn(II) concentration 
      with CR35 oxidizing 27 and 25 microM Mn day(-1) in unamended and amended 
      condition, respectively. CR48 oxidized Mn at the rate of 26 microM Mn day(-1) in 
      unamended medium and 35 microM Mn day(-1) in amended medium. Scanning electron 
      microscope (SEM) observations of both isolates revealed free-living cells in 
      clustered matrices approximately 2 microm diameter. Energy dispersive spectrum of 
      the cell matrix of CR35 cultured in 1 mM Mn detected 30% Mn, while the cell 
      aggregates of CR48 harbored 7-10% Mn. The relatively high specific activity of 
      these mixotrophic bacteria under relatively oligotrophic conditions suggests that 
      they may be responsible for scavenging dissolved Mn from the Carlsberg Ridge 
      waters and could potentially participate in oxidation.
FAU - Fernandes, Sheryl Oliveira
AU  - Fernandes SO
AD  - National Institute of Oceanography, Dona Paula, 403 004 Goa, India.
FAU - Krishnan, K P
AU  - Krishnan KP
FAU - Khedekar, V D
AU  - Khedekar VD
FAU - Loka Bharathi, P A
AU  - Loka Bharathi PA
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Netherlands
TA  - Biometals
JT  - Biometals : an international journal on the role of metal ions in biology, 
      biochemistry, and medicine
JID - 9208478
RN  - 059QF0KO0R (Water)
RN  - 42Z2K6ZL8P (Manganese)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Cell Proliferation/drug effects
MH  - Cells, Cultured
MH  - Dose-Response Relationship, Drug
MH  - *Ecosystem
MH  - Indian Ocean
MH  - Manganese/*metabolism/*pharmacology
MH  - Microscopy, Electron, Scanning
MH  - Oxidation-Reduction
MH  - Oxygen/metabolism
MH  - Pseudomonas/*drug effects/*isolation & purification/physiology
MH  - Water/chemistry
EDAT- 2005/12/08 09:00
MHDA- 2006/04/28 09:00
CRDT- 2005/12/08 09:00
PHST- 2005/07/19 00:00 [received]
PHST- 2005/09/07 00:00 [accepted]
PHST- 2005/12/08 09:00 [pubmed]
PHST- 2006/04/28 09:00 [medline]
PHST- 2005/12/08 09:00 [entrez]
AID - 10.1007/s10534-005-3000-y [doi]
PST - ppublish
SO  - Biometals. 2005 Oct;18(5):483-92. doi: 10.1007/s10534-005-3000-y.