Enhanced Bioaccumulation of Heavy Metals by Bacterial Cells with Surface-Displayed Synthetic Phytochelatins

2002 ◽  
pp. 411-418 ◽  
Author(s):  
Wilfred Chen ◽  
Weon Bae ◽  
Rajesh Mehra ◽  
Ashok Mulchandani
Keyword(s):  
Heavy Metals ◽  
Bacterial Cells

scholarly journals SELECTIVE "STAINING" FOR ELECTRON MICROGRAPHY

1942 ◽  
Vol 76 (1) ◽  
pp. 103-108 ◽  
Author(s):  
Stuart Mudd ◽  
Thomas F. Anderson
Keyword(s):  
Heavy Metals ◽  
Cell Walls ◽  
Differential Staining ◽  
Bacterial Cells ◽  
Selective Staining ◽  
Electron Micrography ◽  
Chemical Effects ◽  
Microchemical Analysis ◽  
Cell Components ◽  
Selective Chemical

The physical basis of contrast and image formation in electron micrography is considered in relation to the possibility of recording selective chemical effects on cell components. A technology of selective microchemical analysis, equivalent to differential staining, is suggested as practicable in electron micrography. Electron pictures of bacteria after exposure to salts of heavy metals have shown the bacterial inner protoplasm, but not the cell walls, to be selectively darkened; shrinkage, coagulation, or escape of protoplasm from the injured cells may result and be recorded in the electron micrographs. Recording of the action of germicidal agents on individual bacterial cells is indicated as one promising field of application of microchemical analysis with the aid of the electron microscope.

Enhanced bioaccumulation of heavy metals by bacterial cells displaying synthetic phytochelatins

2000 ◽  
Vol 70 (5) ◽  
pp. 518-524 ◽  
Author(s):  
Weon Bae ◽  
Wilfred Chen ◽  
Ashok Mulchandani ◽  
Rajesh K. Mehra
Keyword(s):  
Heavy Metals ◽  
Bacterial Cells

scholarly journals Widening the Spaces of Selection: Evolution along Sublethal Antimicrobial Gradients

mBio ◽  
2014 ◽  
Vol 5 (6) ◽  
Author(s):  
Fernando Baquero ◽  
Teresa M. Coque
Keyword(s):  
Heavy Metals ◽  
Antimicrobial Agents ◽  
Metal Resistance ◽  
Water Bodies ◽  
Bacterial Cells ◽  
Low Concentrations ◽  
Selection For ◽  
The Cost ◽  
Selective Effects

ABSTRACT The work of Gullberg et al. (E. Gullberg, L. M. Albrecht, C. Karlsson, L. Sandegren, D. I. Andersson, mBio 5:e01918-14, 2014) indicates that extremely low concentrations of antibiotics and heavy metals are able to compensate for the cost of harboring a plasmid encoding resistances to these inhibitors. Therefore, the “spaces of selection” for plasmids encoding antibiotic or metal resistance along gradients of antimicrobial agents might be huge, and in wide spaces a high number of bacterial cells are exposed to the selective effects. These spaces are even broader if several inhibitors are simultaneously present. Probably very small inhibitor concentrations in the environment, including in sewage and other water bodies, are sufficient to ensure the maintenance and spread of this kind of multiresistance plasmid.

scholarly journals Biotechnological bases of use of natural mineral glauconite in soil-forming processes at development of technogenic massifs and liquidation of enterprises on extraction of minerals

2019 ◽  
Author(s):  
Наталья Щербакова ◽  
Заур Хапцев ◽  
Андрей Захаревич ◽  
Сергей Вениг ◽  
Виктор Сержантов
Keyword(s):  
Heavy Metals ◽  
Plant Growth ◽  
Soil Formation ◽  
Mineralogical Composition ◽  
Bacterial Cells ◽  
Agrobacterium Radiobacter ◽  
Natural Mineral ◽  
Pseudomonas Aureofaciens ◽  
Exchange Processes ◽  
Soil Forming Processes

To initiate the process of soil formation, it is necessary to introduce a culture of microorganisms capable of improving mineral nutrition, plant growth and resistance to adverse factors, regardless of the mineralogical composition of the surface. The advantage of the developed methods is the multifunctionality of the sorbent, which is an abiotic catalyst: the dangerous agent binds physically due to the formed fine-porous structure, and chemically due to the ion exchange processes occurring due to the nature of the layered glauconite silicate. The viability of immobilized glauconite bacterial cells of Agrobacterium radiobacter 204, Rhizobium leguminosarumbiovartrifolii, Flaviobacterium L 30 fulvum, Pseudomonas aureofaciens 1393 BS, amounted to no less than 4 months., while the original biological products are stored no more than 1 month. Key words: glauconite, sorbent, sorption capacity, heavy metals, microorganisms, immobilization on inorganic carriers.

scholarly journals Enhanced Mercury Biosorption by Bacterial Cells with Surface-Displayed MerR

2003 ◽  
Vol 69 (6) ◽  
pp. 3176-3180 ◽  
Author(s):  
Weon Bae ◽  
Cindy H. Wu ◽  
Jan Kostal ◽  
Ashok Mulchandani ◽  
Wilfred Chen
Keyword(s):  
Heavy Metals ◽  
Ice Nucleation ◽  
Genetically Engineered ◽  
Binding Property ◽  
Bacterial Cells ◽  
Toxic Heavy Metals ◽  
Ice Nucleation Protein ◽  
Whole Cell ◽  
In The Wild ◽  
Metalloregulatory Proteins

ABSTRACT The metalloregulatory protein MerR, which exhibits high affinity and selectivity toward mercury, was exploited for the construction of microbial biosorbents specific for mercury removal. Whole-cell sorbents were constructed with MerR genetically engineered onto the surface of Escherichia coli cells by using an ice nucleation protein anchor. The presence of surface-exposed MerR on the engineered strains enabled sixfold-higher Hg2+ biosorption than that found in the wild-type JM109 cells. Hg2+ binding via MerR was very specific, with no observable decline even in the presence of 100-fold excess Cd2+ and Zn2+. The Hg2+ binding property of the whole-cell sorbents was also insensitive to different ionic strengths, pHs, and the presence of metal chelators. Since metalloregulatory proteins are currently available for a wide variety of toxic heavy metals, our results suggest that microbial biosorbents overexpressing metalloregulatory proteins may be used similarly for the cleanup of other important heavy metals.

scholarly journals Enhanced Toxic Metal Accumulation in Engineered Bacterial Cells Expressing Arabidopsis thaliana Phytochelatin Synthase

2003 ◽  
Vol 69 (1) ◽  
pp. 490-494 ◽  
Author(s):  
Sandrine Sauge-Merle ◽  
Stéphan Cuiné ◽  
Patrick Carrier ◽  
Catherine Lecomte-Pradines ◽  
Doan-Trung Luu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Arabidopsis Thaliana ◽  
Metal Binding ◽  
Higher Plants ◽  
Toxic Metal ◽  
Heavy Metal Stress ◽  
Bacterial Cells ◽  
Bacterial Strains ◽  
Gene Encoding

ABSTRACT Phytochelatins (PCs) are metal-binding cysteine-rich peptides, enzymatically synthesized in plants and yeasts from glutathione in response to heavy metal stress by PC synthase (EC 2.3.2.15). In an attempt to increase the ability of bacterial cells to accumulate heavy metals, the Arabidopsis thaliana gene encoding PC synthase (AtPCS) was expressed in Escherichia coli. A marked accumulation of PCs was observed in vivo together with a decrease in the glutathione cellular content. When bacterial cells expressing AtPCS were placed in the presence of heavy metals such as cadmium or the metalloid arsenic, cellular metal contents were increased 20- and 50-fold, respectively. We discuss the possibility of using genes of the PC biosynthetic pathway to design bacterial strains or higher plants with increased abilities to accumulate toxic metals, and also arsenic, for use in bioremediation and/or phytoremediation processes.

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