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Perchlorates are the salts derived from perchloric acid (HClO4). They occur both naturally and through manufacturing. They have been used as a medicine for more than 50 years to treat thyroid gland disorders and are used extensively within the pyrotechnics industry, and ammonium perchlorate is also a component of solid rocket fuel. This book presents current research data from across the globe in the study of perchlorates, their production, uses, and health effects. Some topics discussed, herein, are: trends in the study of the electrochemical stability of perchlorate ions; the structural and vibrational properties of chromyl perchlorate; perchlorate formation in electrochemical water disinfection; metal perchlorates as Lewis acids; alkaline earth metal perchlorates; and removal of perchlorate from water.

Dracorhodin perchlorate has been recently shown to induce apoptotic cell death in cancer cells. However, the molecular mechanisms underlying these effects are unknown in human gastric tumor cells. In this study, effects of Dracorhodin perchlorate on cell viability, cell cycle, and apoptosis were investigated in SGC-7901 cells. The results showed that Dracorhodin perchlorate induced cellular and DNA morphological changes and decreased the viability of SGC-7901 cells. Dracorhodin perchlorate-mediated cell cycle arrest was associated with a marked decrease in protein levels of phosphorylated retinoblastoma and E2F1. Dracorhodin perchlorate-induced apoptosis is mediated via upregulation of p53, inhibiting the activation of PI3K/Akt, and NF-κB, thereby decreasing the expression of the anti-apoptotic proteins, Bcl-2 and Bcl-XL. Interestingly, we also found that Dracorhodin perchlorate significantly suppressed the IGF-1-induced phosphorylation of Akt in the stably expressing EGFP-Akt recombinant CHO-hIR cells and inhibited TNF-induced NF-κB transcriptional activity in the NF-κBp65-EGFP recombinant U2OS cells, indicating that inhibition of PI3K/Akt and NF-κB may provide a molecular basis for the ability of Dracorhodin perchlorate to induce apoptosis. Dracorhodin perchlorate induced up-regulation of p53, thereby resulting in the activation of its downstream targets p21 and Bax following the dissipation of mitochondrial membrane potential and activation of caspase-3 and its substrate, PARP. Moreover, Dracorhodin perchlorate dramatically enhanced the wortmannin- and TNF-induced apoptosis in SGC-7901 cells. These results reveal functional interplay among the PI3K/Akt, p53 and NF-κB pathways that are frequently deregulated in cancer and suggest that their simultaneous targeting by Dracorhodin perchlorate could result in efficacious and selective killing of cancer cells.[PUBLICATION ABSTRACT]

Nitrate and perchlorate have considerable use in technology, synthetic materials, and agriculture; as a result, they have become pervasive water pollutants. Industrial strategies to chemically reduce these oxyanions often require the use of harsh conditions, but microorganisms can efficiently reduce them enzymatically. We developed an iron catalyst inspired by the active sites of nitrate reductase and (per)chlorate reductase enzymes. The catalyst features a secondary coordination sphere that aids in oxyanion deoxygenation. Upon reduction of the oxyanions, an iron(III)-oxo is formed, which in the presence of protons and electrons regenerates the catalyst and releases water.

[This corrects the article DOI: 10.1371/journal.pone.0340252.].

A novel perchlorate-reducing bacterium (PCRB), PMJ, was isolated from the mixed liquor suspended solids in the aerobic tank of a wastewater treatment plant. The 16S ribosomal RNA (rRNA), perchlorate reductase, and chlorite dismutase gene sequences revealed that PMJ belonged to the genus Azospira . PMJ was removed high-strength (700 mg/L) perchlorate and also removed low-strength (≤50 mg/L) perchlorate below the detection limit (2 μg/L) when acetate was used as a sole and carbon source. The maximum specific perchlorate utilization rate, q max, was 0.96 mg ClO 4 − /mg dry cell weight day, and the half-saturation constant, K S , was lower than 0.002 mg ClO 4 − /L. PMJ also utilized inorganic electron donors [(H 2 , S 0 , and Fe(II)] with perchlorate as an electron acceptor. Perchlorate reduction by PMJ was completely inhibited by oxygen and chlorate but was not inhibited by nitrate. In the presence of similar concentrations (100∼140 mg/L) of nitrate and perchlorate, PMJ simultaneously removed both electron acceptors. Therefore, it was concluded that the strains PMJ might possess separate pathways for perchlorate and nitrate reduction. These results indicated that Azospira sp. PMJ could be efficiently used for treating perchlorate-contaminated groundwater and wastewater because many of these water bodies are known to contain both perchlorate and nitrate. In addition, low K S value and autotrophic perchlorate reduction of PMJ might be useful to design the biological treatment systems.

Three new strains of dissimilatory perchlorate-reducing bacteria (DPRB), QD19-16, QD1-5, and P3-1, were isolated from an active sludge. Phylogenetic trees based on 16S rRNA genes indicated that QD19-16, QD1-5, and P3-1 belonged to Brucella , Acidovorax , and Citrobacter , respectively, expanding the distribution of DPRB in the Proteobacteria . The three strains were gram-negative and facultative anaerobes with rod-shaped cells without flagella, which were 1.0–1.6 μm long and 0.5–0.6 μm wide. The three DPRB strains utilized similar broad spectrum of electron donors and acceptors and demonstrated a similar capability to reduce perchlorate within 6 days. The enzyme activity of perchlorate reductase in QD19-16 toward chlorate was higher than that toward perchlorate. The high sequence similarity of the perchlorate reductase operon and chlorite dismutase genes in the perchlorate reduction genomic islands (PRI) of the three strains implied that they were monophyletic origin from a common ancestral PRI. Two transposase genes ( tnp1 and tnp2 ) were found in the PRIs of strain QD19-16 and QD1-5, but were absent in the strain P3-1 PRI. The presence of fragments of IR sequences in the P3-1 PRI suggested that P3-1 PRI had previously contained these two tnp genes. Therefore, it is plausible to suggest that a common ancestral PRI transferred across the strains Brucella sp. QD19-16, Acidovorax sp. QD1-5, and Citrobacter sp. P3-1 through horizontal gene transfer, facilitated by transposases. These results provided a direct evidence of horizontal gene transfer of PRI that could jump across phylogenetically unrelated bacteria through transposase. Key points • Three new DPRB strains can effectively remove high concentration of perchlorate. • The PRIs of three DPRB strains are acquired from a single ancestral PRI. • PRIs are incorporated into different bacteria genome through HGT by transposase.

Perchlorate-a powerful oxidant used in solid rocket fuels by the military and aerospace industry-has been detected in public drinking water supplies of over 11 million people at concentrations of at least 4 parts per billion (ppb). High doses of perchlorate can decrease thyroid hormone production by inhibiting the uptake of iodide by the thyroid. Thyroid hormones are critical for normal growth and development of the central nervous system of fetuses and infants. This report evaluates the potential health effects of perchlorate and the scientific underpinnings of the 2002 draft risk assessment issued by the U.S. Environmental Protection Agency (EPA). The report finds that the body can compensate for iodide deficiency, and that iodide uptake would likely have to be reduced by at least 75% for months or longer for adverse health effects, such as hypothryroidism, to occur. The report recommends using clinical studies of iodide uptake in humans as the basis for determining a reference dose rather than using studies of adverse health effects in rats that serve as EPA's basis. The report suggests that daily ingestion of 0.0007 milligrams of perchlorate per kilograms of body weight-an amount more than 20 times the reference dose proposed by EPA-should not threaten the health of even the most sensitive populations.

This paper focuses on tetraamminecopper(II) perchlorate (TACP), a relatively newly used and popular homemade explosive that is insufficiently described in the literature. The compound was analyzed using commonly used forensic laboratory techniques such as FTIR, Raman, XRPD, and DTA. The TACP molecule was labeled with four 15N atoms on ammonia ligands to assign vibrational modes to the resulting bands. The paper also describes the thermal decomposition of TACP using thermoanalytical methods TGA/MS. The TACP decomposes to the final product CuO in six distinct ranges, releasing N2O, NO, HCl, O2, H2O, and NH3. It has been found that TACP is not a stable compound and will decompose spontaneously to ammonia, ammonium perchlorate, and basic copper perchlorate within a few months if exposed to air at room temperature. Residues of precursors have been detected in TACP prepared by four improvised preparation methods published on the Internet. These residues can be used to identify the precursor used in the preparation. The post-blast residues of TACP are of ordinary shape, but the use of TACP as an explosive can be indicated by the presence of a high content of copper and chlorine atoms in post-blast residues. The results of canine detection of TACP indicate that the dog is able to detect TACP, but the dog is likely to focus on the smell of ammonia in the TACP odor. [Display omitted] •TACP vibrational spectra are published, bonds were assigned using labeled compounds.•TACP precursors used for its improvised preparation can be identified.•TACP decomposes to ammonia, ammonium perchlorate, and basic copper perchlorate on air•TACP post-blast residues are characteristic with high content of copper and chlorine.•The sniffer dog trained for TACP detection is likely targeting the ammonia odor in TACP.