scholarly journals A Review of Asbestos Bioweathering by Siderophore-Producing Pseudomonas: A Potential Strategy of Bioremediation

2020 ◽  
Vol 8 (12) ◽  
pp. 1870
Author(s):  
Sébastien R. David ◽  
Valérie A. Geoffroy
Keyword(s):  
Transition Metal ◽  
Metal Chelation ◽  
Silicate Minerals ◽  
Asbestos Fibers ◽  
Mineral Alteration ◽  
High Concentrations ◽  
Potential Strategy ◽  
Microbial Weathering ◽  
Detoxification Process

Asbestos, silicate minerals present in soil and used for building constructions for many years, are highly toxic due primarily to the presence of high concentrations of the transition metal iron. Microbial weathering of asbestos occurs through various alteration mechanisms. Siderophores, complex agents specialized in metal chelation, are common mechanisms described in mineral alteration. Solubilized metals from the fiber can serve as micronutrients for telluric microorganisms. The review focuses on the bioweathering of asbestos fibers, found in soil or manufactured by humans with gypsum (asbestos flocking) or cement, by siderophore-producing Pseudomonas. A better understanding of the interactions between asbestos and bacteria will give a perspective of a detoxification process inhibiting asbestos toxicity.

scholarly journals Glutathione-Dependent Conversion ofN-Ethylmaleimide to the Maleamic Acid by Escherichia coli: an Intracellular Detoxification Process

2000 ◽  
Vol 66 (4) ◽  
pp. 1393-1399 ◽  
Author(s):  
D. McLaggan ◽  
H. Rufino ◽  
M. Jaspars ◽  
I. R. Booth
Keyword(s):  
Escherichia Coli ◽  
Time Course ◽  
E Coli ◽  
Transient Activation ◽  
Low Concentrations ◽  
Maleamic Acid ◽  
High Concentrations ◽  
Hydrolysis Of ◽  
Strong Activator ◽  
Detoxification Process

ABSTRACT The electrophile N-ethylmaleimide (NEM) elicits rapid K+ efflux from Escherichia coli cells consequent upon reaction with cytoplasmic glutathione to form an adduct, N-ethylsuccinimido-S-glutathione (ESG) that is a strong activator of the KefB and KefC glutathione-gated K+ efflux systems. The fate of the ESG has not previously been investigated. In this report we demonstrate that NEM andN-phenylmaleimide (NPM) are rapidly detoxified by E. coli. The detoxification occurs through the formation of the glutathione adduct of NEM or NPM, followed by the hydrolysis of the imide bond after which N-substituted maleamic acids are released. N-Ethylmaleamic acid is not toxic to E. coli cells even at high concentrations. The glutathione adducts are not released from cells, and this allows glutathione to be recycled in the cytoplasm. The detoxification is independent of new protein synthesis and NAD+-dependent dehydrogenase activity and entirely dependent upon glutathione. The time course of the detoxification of low concentrations of NEM parallels the transient activation of the KefB and KefC glutathione-gated K+ efflux systems.

BIOACCUMULATION AND METABOLIC EFFECTS OF ZINC ON MARINE ROCK OYSTER, CRASSOSTREA CATTUCKENSIS

2017 ◽  
Vol 23 (1) ◽  
Author(s):  
G. D. SURYAWANSHI
Keyword(s):  
Lipid Content ◽  
Adductor Muscle ◽  
Metabolic Effects ◽  
Body Parts ◽  
High Concentration ◽  
Experimental Control ◽  
Adductor Muscles ◽  
Increase Rate ◽  
High Concentrations ◽  
Detoxification Process

The Indian rock oysters, Crassostrea cattuckensis (80-90 mm shell length) were exposed to sub lethal levels of zinc for 15 days and 30 days for metal accumulation and next 15 days for metal depuration. The oysters, which served as experimental control after 15 days showed high amount of lipid (mg/100 mg) in hepatopancreas ( 3.32) followed by gills (3.20), mantle (3.08), gonad (2.90), adductor muscle (2.78) and siphon (2.11). During 15 days metal exposed oysters to (0.65) and (0.94) ppm concentrations there was changes observed in different body parts when compared to experimental control. The decreased rate upon 15 days in (0.65 ppm) concentrations was in mantle (2.96), than gill (2.22), hepatopancreas (1.72), gonad (1.59), siphon (1.51) and adductor muscle (1.50). While in (0.94 ppm) the protein was decreased in adductor muscle (2.51), gonad (1.61), siphon (1.44), gill (1.42) and it increased in mantle (3.90) and hepatopancreas (3.34) when it was compared to experimental control. Whereas upon 30 days exposure the lipid content increased among body parts in both concentration except the gills (1.35), gonads (1.97) and hepatopancreas (1.66) in higher concentration when compared with experimental control. The lipid increased in (0.65 ppm) from gonad (2.29), hepatopancreas (2.25), adductor muscle (2.22), gills (2.20), mantle (2.14) and siphon (1.44). While in (0.94 ppm) lipid increase trend was from mantle (4.27), adductor muscle (2.46) and siphon (1.42) and decreased from gonad (1.97), hepatopancreas (1.66) and gills (1.35) when compared with 30 days experimental control. During detoxification process the lipid content was increased in both concentrations except gill (2.11) in low and adductor muscle (0.99), siphon (0.74) in high concentrations when compared with respective concentrations of 15 days exposed oysters. The increase rate in low concentration was from mantle (4.32) than from adductor muscles (4.12), gonad (3.60), hepatopancreas (2.46) and siphon (1.05). In high concentration it was more in hepatopancreas (4.93) than gonad (4.42), gills (4.08) and mantle (4.01).

The Effects of Transition Metal Substitutions in the NbTe4-TaTe4 Charge-Density Wave System

1992 ◽  
Vol 45 (9) ◽  
pp. 1363 ◽  
Author(s):  
JC Bennett ◽  
FW Boswell ◽  
A Prodan ◽  
JM Corbett ◽  
S Ritchie
Keyword(s):  
Transition Metal ◽  
Charge Density ◽  
Charge Density Wave ◽  
Room Temperature ◽  
Density Wave ◽  
Dark Field ◽  
Wave System ◽  
Incommensurate Modulation ◽  
High Concentrations ◽  
A Charge

At room temperature, the structures of TaTe4 and NbTe4 are modulated by the presence of a charge-density wave which in the former compound is commensurate with the parent lattice and in the latter incommensurate. In addition, a series of incommensurate mixed crystals ( Tal-xNbx )Te4 (0 ≤ x ≤) exist in which the modulation wavevector increases as a function of x. In this paper, we report the occurrence of a systematic variation in the period of the charge-density wave upon substitution of the transition metal elements Ti, Zr or V for either Nb or Ta. Electron diffraction experiments reveal that, in TaTe4, substitutions of Group 4 elements Ti and Zr result in an incommensurate modulation with a decrease in the modulation wavevector q. In NbTe4, substitutions of Ti or Zr also reduce q, in this case towards the commensurate value, and, at sufficiently high concentrations, a commensurate phase is stabilized at room temperature. Vanadium substitutions in NbTe4 result in a slight increase in q. Satellite dark-field images reveal the presence of defects in the modulation structures of the doped crystals. The above results are discussed in terms of the factors which determine the charge-density wave periodicity in the NbTe4-TaTe4 system.

scholarly journals Sargassum horneri ethanol extract containing polyphenols attenuates PM-induced oxidative stress via ROS scavenging and transition metal chelation

2021 ◽  
Vol 79 ◽  
pp. 104401
Author(s):  
Hyo Jin Kim ◽  
Kalahe Hewage Iresha Nadeeka Madushani Herath ◽  
Duong Thi Thuy Dinh ◽  
Hyun-Soo Kim ◽  
You-Jin Jeon ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Transition Metal ◽  
Ethanol Extract ◽  
Sargassum Horneri ◽  
Metal Chelation ◽  
Ros Scavenging

scholarly journals Concomitant Effects of Transition Metal Chelation and Solvent Polarity on the First Molecular Hyperpolarizability of 4-Methoxyacetophenone Thiosemicarbazone: A DFT Study

2016 ◽  
Vol 2016 ◽  
pp. 1-19 ◽  
Author(s):  
Nyiang Kennet Nkungli ◽  
Julius Numbonui Ghogomu
Keyword(s):  
Transition Metal ◽  
Density Functional ◽  
Broad Band ◽  
Solvent Polarity ◽  
Dielectric Constants ◽  
Dft Study ◽  
Electromagnetic Spectrum ◽  
Metal Chelation ◽  
First Hyperpolarizability ◽  
Nlo Response

Nonlinear optical (NLO) properties of organic and metal-organic materials are of considerable interest to emerging optoelectronic and photonic technologies. Much work has been carried out on the former materials but the latter ones have received less attention till date. Herein, a density functional theory (DFT) study on the combined effects of transition metal chelation and solvent polarity on the first hyperpolarizability (βtot) of 4-methoxyacetophenone thiosemicarbazone (MAPTSC) is reported. MAPTSC exhibits a tautomeric form with higher optical nonlinearity rendering its NLO response in polar solvents potentially switchable. Our results have revealed significant modifications of the first hyperpolarizability of MAPTSC upon complexation with different transition metal chlorides in the presence of solvents with varying dielectric constants. Therefore, its second-order NLO response is highly tunable by the synergy of transition metal chelation and solvent polarity. MAPTSC and its Zn(II) and Pt(II) chloride complexes are promising NLO materials because their gas-phase βtot values are larger than those of the prototype push-pull molecules, para-nitroaniline (PNA) and urea, by factors of about 1.40–1.76 and 19.57–37.24, respectively; these factors greatly increase in polar solvent medium. Moreover, they possess high optical transparencies in the visible region of the electromagnetic spectrum which mitigate transparency/nonlinearity trade-offs, thereby increasing the likelihood of broad band NLO response.

Asbestos Fibers in Sake

1988 ◽  
Vol 51 (9) ◽  
pp. 737-739 ◽  
Author(s):  
SHUZO OGINO ◽  
NOBUTAKA FUKUMORI ◽  
TETSUKO YASUNO ◽  
MASAMICHI KOSEKI ◽  
MASAYOSHI KAZAMA
Keyword(s):  
Electron Microscope ◽  
Detection Limit ◽  
Transmission Electron Microscope ◽  
Detection Limits ◽  
The Body ◽  
The Other ◽  
Filtration Process ◽  
Asbestos Fibers ◽  
Transmission Electron ◽  
High Concentrations

Asbestos filters have been widely used to clear beverages in many countries including Japan, and despite warnings from the authorities, some Japanese sake companies have continued using such filters until recently. Forty-seven Japanese sake samples were analyzed using a transmission electron microscope to detect contamination with asbestos fibers. The concentrations of fibers found in sake samples ranged from <7.8 × 103 fibers/L (the detection limit) to 1.96 × 108 fibers/L. Ten sake manufacturers provided information as to whether they had used asbestos in the filtration process and the remaining 37 did not (unknown group). Five out of the 10 manufacturers from which information was available had used asbestos (with asbestos group), and the other 5 had not (without asbestos group). The concentrations of fibers in the samples of the “with asbestos” group were more than 7.7 × 106 fibers/L while those in the “without asbestos” group did not exceed 2.8 × 105 fibers/L. The concentrations of fibers in the samples of the “unknown group” ranged from below the detection limits to 1.46 × 108 fibers/L. Some brands of sake showed extremely high concentrations of asbestos fibers, and therefore it may be necessary to investigate the fate of ingested asbestos in the body and its possible carcinogenicity.

scholarly journals Hazardous Elements in Asbestos Tremolite from the Basilicata Region, Southern Italy: A First Step

Fibers ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 47
Author(s):  
Claudia Ricchiuti ◽  
Dolores Pereira ◽  
Rosalda Punturo ◽  
Eugenia Giorno ◽  
Domenico Miriello ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Toxic Elements ◽  
Southern Italy ◽  
Optical Emission ◽  
Emission Spectrometry ◽  
Inductively Coupled ◽  
Asbestos Fibers ◽  
Basilicata Region ◽  
High Concentrations

In this paper, we report the quantification of potentially toxic elements (PTEs) hosted into two tremolite asbestos from Episcopia and San Severino Lucano villages (Basilicata region, Southern Italy). Micro X-ray fluorescence and Inductively Coupled Plasma spectroscopy with Optical Emission Spectrometry techniques were used to quantify the concentration of major, minor (Si, Mg, Ca, Al, Fe, Mn) and trace elements (As, Ba, Cd, Co, Cr, Cu, Li, Mo, Ni, Pb, Sb, Sn Sr, Ti, Te, V, W, Zn, Zr), with the aim of providing available data useful for the determination of the asbestos fibers toxicity. Results show that in the two studied samples there exist high concentrations of Fe, Mn, Cr and Ni which could lead to the high toxicity of the mineral fibers. By considering the pseudo-total PTEs amounts in each tremolite asbestos, it is possible to affirm that one of the samples is more enriched in toxic elements than the other one (3572 ppm versus 1384 ppm). These PTEs can represent a source of risk to human health since they may be transported away from the geological outcrops, through asbestos in the air, water and soils and thus encountering the human body.

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