Document Detail

Nickel uptake by Pseudomonas aeruginosa: role of modifying factors.
MedLine Citation:
PMID:  9767709     Owner:  NLM     Status:  MEDLINE    
Pseudomonas aeruginosa cells growing in minimal medium were 40-fold more sensitive to Ni2+ than cells growing in enriched medium, suggesting a possible protective role of medium ingredients. Likewise, cells pre-grown in enriched medium showed a high Km (6.15 mM) and increased Ni2+ uptake (950 nmol mg-1 protein, 1h) over cells pre-sown in minimal medium (Km, 0.48 mM; 146 nmol mg-1 protein, 1 h). The overall pattern indicates that cells pre-grown in enriched medium were characterized by having lowered affinity towards Ni2+ than those with minimal medium background. The enhanced Ni2+ uptake by enriched medium-grown cells can be correlated with the improved metabolic state of the cells. Ni2+ uptake was optimum at neutrality (pH 7.0). A major Ni2+ transport system was competitively inhibited by Mg2+, Zn2+, Cd2+, or Co2+ (400 microM each). Noticeably, a minor Ni2+ transport pathway was still operative even in the higher concentration range of Mg2+ (4 mM and 40 mM). The stimulation of Ni2+ uptake monitored in the presence of different carbon sources (0.5% wt/vol, each) showed the sequence: glucose (1.6-fold) > phenol = gallic acid (1.5-fold). Succinate, in comparison, reduced Ni2+ uptake (0.5-fold) possibly because of its acting as a metal chelator as well. Sensitivity of Ni2+ transport towards methyl viologen, azide, 2-4 DNP, and DCCD suggested that transport was energy-linked.
P Sar; S K Kazy; R K Asthana; S P Singh
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Current microbiology     Volume:  37     ISSN:  0343-8651     ISO Abbreviation:  Curr. Microbiol.     Publication Date:  1998 Nov 
Date Detail:
Created Date:  1998-12-02     Completed Date:  1998-12-02     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7808448     Medline TA:  Curr Microbiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  306-11     Citation Subset:  IM    
Algal Research Laboratory, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi 221005, India.
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MeSH Terms
Cations, Divalent / pharmacology
Culture Media
Dicyclohexylcarbodiimide / pharmacology
Glucose / pharmacology
Hydrogen-Ion Concentration
Ion Transport / drug effects
Nickel / metabolism*
Pseudomonas aeruginosa / growth & development,  metabolism*
Soil Microbiology
Reg. No./Substance:
0/Cations, Divalent; 0/Culture Media; 50-99-7/Glucose; 538-75-0/Dicyclohexylcarbodiimide; 7440-02-0/Nickel

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