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Environmental Science & Technology May 2010In this study, we investigated local structures of Sb species in synthetic Sb(V)-coprecipitated and -adsorbed ferrihydrite and goethite, which are common iron(III)...
In this study, we investigated local structures of Sb species in synthetic Sb(V)-coprecipitated and -adsorbed ferrihydrite and goethite, which are common iron(III) oxyhydroxides in environment, at various Sb/Fe molar ratios by extended X-ray absorption fine structure (EXAFS) analyses. The EXAFS analyses showed that Sb(V) is adsorbed on ferrihydrite and goethite by the formation of an inner-sphere surface complex at pH 7.5. In the EXAFS spectra of the coprecipitated ferrihydrite and goethite, some features of the spectra significantly differed from those in the adsorbed samples. The EXAFS simulation indicated that the difference is due to the larger coordination number of the Fe atom to the Sb atom in the coprecipitation samples, indicating a structural incorporation (heterovalent substitution) of Sb(V) into ferrihydrite and goethite. The incorporation of Sb(V) into the structure was also confirmed in natural iron(III) oxyhydroxides in contaminated soil near an Sb mine tailing using mu-EXAFS. This study directly provided the first evidence for the structural incorporation of Sb(V) into the iron(III) oxide structure. Our findings are important for understanding the fate of Sb in the aquatic environment because the behavior of the elements incorporated into solids by such a substitution is not greatly influenced by aquatic factors such as the pH and ionic strength because of isolation of the incorporated metal(loid) ions from the aqueous phase.
Topics: Adsorption; Antimony; Iron Compounds; Minerals
PubMed: 20426473
DOI: 10.1021/es903901e -
Bioanalysis Apr 2021A high-throughput method using inductively coupled plasma mass spectrometry (ICP-MS) was developed and validated for the quantitative analysis of antimony in human...
A high-throughput method using inductively coupled plasma mass spectrometry (ICP-MS) was developed and validated for the quantitative analysis of antimony in human plasma and peripheral blood mononuclear cells from patients with cutaneous leishmaniasis undergoing treatment with meglumine antimoniate. Antimony was digested in clinical samples with 1% tetramethylammonium hydroxide/1% EDTA and indium was used as internal standard. Accuracy, precision and stability were evaluated. Taking the lower limit of quantitation to be the lowest validation concentration with precision and accuracy within 20%, the current assay was successfully validated from 25 to 10000 ng/ml for antimony in human plasma and peripheral blood mononuclear cells. This protocol will serve as a baseline for future analytical designs, aiming to provide a reference method to allow inter-study comparisons.
Topics: Antimony; Antiprotozoal Agents; Humans; Leishmania; Mass Spectrometry; Meglumine Antimoniate; Molecular Structure; Parasitic Sensitivity Tests
PubMed: 33829863
DOI: 10.4155/bio-2021-0013 -
Molecules (Basel, Switzerland) Jun 2009Pentavalent antimonials, including meglumine antimoniate and sodium stibogluconate, have been used for more than half a century in the therapy of the parasitic disease... (Review)
Review
Pentavalent antimonials, including meglumine antimoniate and sodium stibogluconate, have been used for more than half a century in the therapy of the parasitic disease leishmaniasis. Even though antimonials are still the first-line drugs, they exhibit several limitations, including severe side effects, the need for daily parenteral administration and drug resistance. The molecular structure of antimonials, their metabolism and mechanism of action are still being investigated. Some recent studies suggest that pentavalent antimony acts as a prodrug that is converted to active and more toxic trivalent antimony. Other works support the direct involvement of pentavalent antimony. Recent data suggest that the biomolecules, thiols and ribonucleosides, may mediate the actions of these drugs. This review will summarize the progress to date on the chemistry and biochemistry of pentavalent antimony. It will also present the most recent works being done to improve antimonial chemotherapy. These works include the development of simple synthetic methods for pentavalent antimonials, liposome-based formulations for targeting the Leishmania parasites responsible for visceral leishmaniasis and cyclodextrin-based formulations to promote the oral delivery of antimony.
Topics: Animals; Antimony; Humans; Leishmania; Leishmaniasis; Liposomes; Organometallic Compounds; Trypanocidal Agents
PubMed: 19633606
DOI: 10.3390/molecules14072317 -
The Science of the Total Environment Jun 2022Bosea sp. AS-1 is an arsenite [As(III)] and antimonite [Sb(III)] oxidizer previously isolated by our group from the Xikuangshan Antimony (Sb) Mine area. Our previous...
Bosea sp. AS-1 is an arsenite [As(III)] and antimonite [Sb(III)] oxidizer previously isolated by our group from the Xikuangshan Antimony (Sb) Mine area. Our previous study showed that Bosea sp. AS-1 had a preference for oxidizing As(III) or Sb(III) with different carbon sources, which suggested that different metabolic mechanisms may be utilized by the bacteria to survive in As(III)- or Sb(III)-contaminated environments. Here, we conducted whole-genome and transcriptome sequencing to reveal the molecular mechanisms utilized by Bosea sp. AS-1 to resist As(III) or Sb(III). We discovered that AS-1 acquired various As- and Sb-resistant genes in its genome and might resist As(III) or Sb(III) through the regulation of multiple pathways, such as As and Sb metabolism, the bacterial secretion system, oxidative phosphorylation, the TCA cycle and bacterial flagellar motility. Interestingly, we discovered that genes of the type IV secretion system (T4SS) were activated in response to Sb(III), and inhibiting T4SS activity in AS-1 dramatically reduced its oxidation efficiency and tolerance to Sb(III). To our knowledge, this is the first study showing the activation of T4SS genes by Sb and a direct involvement of T4SS in bacterial Sb resistance. Our findings establish the T4SS as an important Sb resistance factor in bacteria and may help us understand the spread of Sb resistance genes in the environment.
Topics: Antimony; Arsenites; Bacteria; Gene Expression Profiling; Type IV Secretion Systems
PubMed: 35231521
DOI: 10.1016/j.scitotenv.2022.154168 -
The Journal of Infectious Diseases May 2006Failure of antimonial therapy has been increasingly reported in anthroponotic visceral leishmaniasis and in cutaneous disease. The role of drug resistance in treatment...
BACKGROUND
Failure of antimonial therapy has been increasingly reported in anthroponotic visceral leishmaniasis and in cutaneous disease. The role of drug resistance in treatment failure has been difficult to ascertain because therapeutic response is multifactorial, and the efficacy of antimonial drugs depends on an effective immune response. In this study, we sought to determine whether standard treatment selects for resistant organisms and whether drug resistance contributes to treatment failure.
METHODS
We evaluated the susceptibility to antimony of 19 strains isolated before treatment with meglumine antimoniate and 21 strains isolated at treatment failure from 20 patients. The 50% effective dose (ED50) of antimony in the form of additive-free meglumine antimoniate was determined for intracellular amastigotes in human promonocytic U-937 cells.
RESULTS
Before treatment, 16% of strains (3/19) showed primary resistance (ED50 of >128 microg Sb/mL), whereas 84% (16/19) were susceptible (ED50 of <20 microg Sb/mL). However, 88% of susceptible strains (14/16) had ED90 values of >128 microg Sb/mL. At treatment failure, 40% of strains (8/20) were resistant. Secondary resistance was documented in 4 patients.
CONCLUSIONS
Primary and secondary resistance to antimony can contribute to treatment failure in American cutaneous leishmaniasis. Selection for resistance to antimony occurs during standard treatment with antimonial drugs, and primary resistance to antimony supports the plausibility of anthroponotic transmission.
Topics: Adolescent; Adult; Animals; Antimony; Antiprotozoal Agents; Child; Drug Resistance; Female; Humans; Leishmania; Leishmaniasis, Cutaneous; Male; Meglumine; Meglumine Antimoniate; Middle Aged; Organometallic Compounds; Parasitic Sensitivity Tests; Treatment Failure; U937 Cells
PubMed: 16619185
DOI: 10.1086/503371 -
Ultrasonics Sonochemistry Jan 2010The substantiated isolation of the antimony subiodide (Sb(3)I) is presented for the first time. It has been prepared using elemental Sb and I in ethanol under ultrasonic...
The substantiated isolation of the antimony subiodide (Sb(3)I) is presented for the first time. It has been prepared using elemental Sb and I in ethanol under ultrasonic irradiation at 323 K. Its composition was characterized using X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray analysis (EDAX). The scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) investigations exhibit that the samples are made up of large quantity of nanoparticles with diameters smaller than 20 nm and single crystalline in nature. The interplanar spacings in Sb(3)I that have been determined using powder X-ray diffraction (XRD), selected area electron diffraction (SAED) and HRTEM are very similar. Surprisingly, the registered XRD patterns are identical to the one reported earlier for Sb(4)O(5)I(2).
Topics: Antimony; Iodides; Radiation Dosage; Sonication
PubMed: 19540144
DOI: 10.1016/j.ultsonch.2009.05.016 -
The Journal of Physical Chemistry. A Jan 2021Mössbauer spectroscopy, nuclear forward scattering, and Raman spectroscopy were applied to study redox transformations of the synthesized mixed-valence (III/V) antimony...
Mössbauer spectroscopy, nuclear forward scattering, and Raman spectroscopy were applied to study redox transformations of the synthesized mixed-valence (III/V) antimony oxide. The transformations were induced by a culture of a hyperthermophilic archaeon of the genus . The applied methods allowed us to reveal the minor decrease of ca. 11.0 ± 1.2% of the antimony(V) content of the mixed-valence oxide with the concomitant increase of antimony(III). The method sensitivities for the quantitative assessment of the Sb(III/V) ratio have been considered.
Topics: Antimony; Oxidation-Reduction; Oxides; Pyrobaculum; Spectroscopy, Mossbauer; Spectrum Analysis, Raman
PubMed: 33389998
DOI: 10.1021/acs.jpca.0c08865 -
Acta Microbiologica Et Immunologica... Mar 2024Cutaneous Leishmaniasis (CL) is one of the world's neglected diseases which is caused by Leishmania spp. The aim of this study was to assess molecular profile and...
Cutaneous Leishmaniasis (CL) is one of the world's neglected diseases which is caused by Leishmania spp. The aim of this study was to assess molecular profile and antimony resistance of Leishmania isolated from human and rodent hosts. Samples were collected from suspected CL patients referred to health centres and wild rodent's traps in Gonbad-e-Qabus region, north-eastern Iran. Smears were subjected to PCR-RFLP to identify Leishmania species. In addition, ITS1-PCR products were sequenced for phylogenetic analysis. Clinical isolates and rodent samples were subjected to MTT assay to determine IC50 values and in vitro susceptibilities. Expression levels of antimony resistance-related genes were determined in CL isolates. Out of 1,949 suspected patients with CL and 148 rodents, 1,704 (87.4%) and 6 (4.05%) were positive with direct smear, respectively. Digestion patterns of BusRI (HaeIII) endonuclease enzyme were similar to what expected for Leishmania major. Phylogenetic analysis revealed that the highest interspecies similarity was found between current L. major sequences with L. major obtained from Russia and Uzbekistan. Out of 20 L. major samples tested, 13 (65%) were resistant to meglumine antimoniate (MA) treatment, with an activity index (AI) exceeding 4. The remaining 7 samples (35%) responded to MA treatment and were classified as sensitive isolates, with a confirmed sensitive phenotype based on their AI values. The comparison expression analysis of three major antimony resistance-associated genes in unresponsive clinical isolates demonstrated significant fold changes for TDR1 (4.78-fold), AQP1 (1.3-fold), and γ-GCS (1.17-fold) genes (P < 0.05). Herein, we demonstrate genetic diversity and antimony resistance of L. major isolated from human and reservoir hosts in north-eastern Iran, which could be the basis for planning future control strategies.
Topics: Animals; Humans; Leishmania major; Phylogeny; Antimony; Rodentia; Leishmaniasis, Cutaneous; Meglumine Antimoniate
PubMed: 38520480
DOI: 10.1556/030.2024.02194 -
Experimental Parasitology Oct 2013Pentavalent antimonial compounds have been the first line therapy for leishmaniasis; unfortunately the rate of treatment failure of anthroponotic cutaneous leishmaniasis...
Pentavalent antimonial compounds have been the first line therapy for leishmaniasis; unfortunately the rate of treatment failure of anthroponotic cutaneous leishmaniasis (ACL) is increasing due to emerging of drug resistance. Elucidation of the molecular mechanisms operating in antimony resistance is critical for development of new strategies for treatment. Here, we used a cDNA-AFLP approach to identify gene(s) which are differentially expressed in resistant and sensitive Leishmania tropica field isolates. We identified five genes, aquaglyceroporin (AQP1) acts in drug uptake, ATP-binding cassette (ABC) transporter (MRPA) involved in sequestration of drug, phosphoglycerate kinase (PGK) implicated in glycolysis metabolism, mitogen activated protein kinase (MAPK) and protein tyrosine phosphatase (PTP) responsible for phosphorylation pathway. The results were confirmed using real time RT-PCR which revealed an upregulation of MRPA, PTP and PGK genes and downregulation of AQP1 and MAPK genes in resistant isolate. To our knowledge, this is the first report of identification of PTP and PGK genes potentially implicated in resistance to antimonials. Our findings support the idea that distinct biomolecules might be involved in antimony resistance in L. tropica field isolates.
Topics: Amplified Fragment Length Polymorphism Analysis; Antimony; Antiprotozoal Agents; Cell Line; DNA Fragmentation; DNA, Complementary; DNA, Protozoan; Drug Resistance; Genes, Protozoan; Inhibitory Concentration 50; Leishmania tropica; Meglumine; Meglumine Antimoniate; Organometallic Compounds; Parasitic Sensitivity Tests; RNA, Protozoan; Real-Time Polymerase Chain Reaction
PubMed: 23928349
DOI: 10.1016/j.exppara.2013.07.018 -
Environmental Toxicology Oct 2010Laboratory culture experiments have shown that antimony biomethylation can result from bacterial and fungal activity under both aerobic and anaerobic conditions....
Laboratory culture experiments have shown that antimony biomethylation can result from bacterial and fungal activity under both aerobic and anaerobic conditions. However, in the light of our current knowledge of antimony solubility and equilibria, critical analysis of the conditions used in published laboratory studies reveals that solution chemistry was generally overlooked and oversaturated solutions were used. As a result, it is very difficult, if not impossible, to establish reliable observed effect-concentration relationships in the experiments published.
Topics: Aerobiosis; Anaerobiosis; Antimony; Culture Media; Environmental Monitoring; Methylation; Soil Pollutants; Solubility; Water Pollutants, Chemical
PubMed: 20549617
DOI: 10.1002/tox.20587