A Novel Nickel Resistance Determinant Found in Sewage-Associated Bacteria

1997 ◽  
Vol 33 (3) ◽  
pp. 230-239 ◽  
Author(s):  
R.W. Pickup ◽  
H.E.H. Mallinson ◽  
G. Rhodes ◽  
L.K. Chatfield
2009 ◽  
Vol 191 (19) ◽  
pp. 5976-5987 ◽  
Author(s):  
Adhikarla Haritha ◽  
Korripally Prem Sagar ◽  
Anand Tiwari ◽  
Patnala Kiranmayi ◽  
Agnes Rodrigue ◽  
...  

ABSTRACT We report here the identification and characterization of mrdH, a novel chromosomal metal resistance determinant, located in the genomic island 55 of Pseudomonas putida KT2440. It encodes for MrdH, a predicted protein of ∼40 kDa with a chimeric domain organization derived from the RcnA and RND (for resistance-nodulation-cell division) metal efflux proteins. The metal resistance function of mrdH was identified by the ability to confer nickel resistance upon its complementation into rcnA mutant (a nickel- and cobalt-sensitive mutant) of Escherichia coli. However, the disruption of mrdH in P. putida resulted in an increased sensitivity to cadmium and zinc apart from nickel. Expression studies using quantitative reverse transcription-PCR showed the induction of mrdH by cadmium, nickel, zinc, and cobalt. In association with mrdH, we also identified a conserved hypothetical gene mreA whose encoded protein showed significant homology to NreA and NreA-like proteins. Expression of the mreA gene in rcnA mutant of E. coli enhanced its cadmium and nickel resistance. Transcriptional studies showed that both mrdH and mreA underwent parallel changes in gene expression. The mobile genetic elements Tn4652 and IS1246, flanking mrdH and mreA were found to be induced by cadmium, nickel, and zinc, but not by cobalt. This study is the first report of a single-component metal efflux transporter, mrdH, showing chimeric domain organization, a broad substrate spectrum, and a location amid metal-inducible mobile genetic elements.


2009 ◽  
Vol 1 (2) ◽  
Author(s):  
Risa Nofiani ◽  
Siti Nurbetty ◽  
Ajuk Sapar

<p>The increase of issues on the antibiotics resistant pathogenic bacteria has triggered high exploration for new antimicrobial compounds. One of the potential sources is sponge-associated bacteria. The aim of this study was to get sponge-associated bacteria extract containing antimicrobial activities. On the basis screening of antimicrobial activity using by streaking on agar medium, there were two potential isolates with antimicrobial activities namely LCS1 and LCS2. The two isolates were cultivated,then secondary metabolite product were extracted using methanol as a solvent. Minimum inhibitory concentrations (MICs) of extract LCS 1 were 1,000 μg/well for S. aureus, 950 μg/well for Salmonella sp.and 800 μg/well for Bacillus subtilis. Minimum inhibitory concentrations of extract LCS 2 were 500 μg/well for S. aureus, 1,050 μg/well for Salmonella sp., 750 μg/well for Bacillus subtilis, 350 μg/well for P. aeruginosa, 750 μg/sumur terhadap B. subtilis. Based on the MIC values, the two assay extracts have a relatively low antimicrobial activity.</p> <p>Keywords:Antimicrobial,Sponges associated bacteria,MICs</p>


Alloy Digest ◽  
1968 ◽  
Vol 17 (3) ◽  

Abstract EXCELSIOR is a copper-nickel resistance alloy recommended for low temperature resistors and heavy duty rheostats. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, and joining. Filing Code: Cu-186. Producer or source: H. K. Porter Company Inc..


2020 ◽  
Vol 16 (9) ◽  
pp. 1273-1280
Author(s):  
Giuseppina Tommonaro ◽  
Ali M. El-Hagrassi ◽  
Walid Fayad ◽  
Carmine Iodice ◽  
Kamel H. Shaker ◽  
...  

Background: Colorectal cancer represents one of the prominent causes of mortality worldwide in men and women. The objective of this study was to search for new potential anticancer compounds, both in prevention and treatment of colorectal cancer. The anticancer potential of marine bacterial extracts against Human colorectal carcinoma cell line (HCT116) was evaluated as well as the partial identification of bioactive metabolites. Methods: All bacterial extracts were tested for their cytotoxicity against HCT116 cell line by means of MTT assay. The highly cytotoxic dichloromethane extracts of marine sponge-associated bacteria Vibrio sp. and Bacillus sp. were analyzed by GC-MS. Results: Two fractions, Vib3 and Bac3, exhibited a very interesting cytotoxicity against human colorectal carcinoma (HCT116) cell line, with a percentage of cytotoxicity of 96.04 % and 29.48 %, respectively. Discussion: The GC-MS analysis revealed the presence of two major fatty acids, palmitic and oleic acids, in Vib3 fraction and fatty acid esters and phenolic compounds in Bac3 fraction. Conclusion: Based on previous literature, it may be hypothesized that the anticancer activity of bacterial extracts could be, at least partially, to the fatty acids fraction.


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