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PubMed2004

Effects of sodium chlorate on toxin production by Escherichia coli O157:H7.

Chlorate kills E. coli O157:H7 and has been proposed as a feed additive to be included in cattle rations immediately prior to slaughter to reduce E. coli O157: H7 populations in the gut. Antibiotic usage is not recommended in cases of E. coil O157:H7-induced hemorrhagic colitis because some antibiotics stimulate increased toxin production. This study was undertaken to determine if chlorate treatment affected toxin production. Pure cultures of E. coil O157:H7 were treated with 1/4 MIC of antibiotics (ampicillin, tetracycline, ceftiofur, gentamicin, monensin, tylosin, penicillin, ciprofloxacin, and novobiocin); toxin production was significantly increased by some antibiotics, but not by chlorate. Studies with mixed fecal bacteria demonstrated that chlorate killed E. coli O157:H7, but again did not stimulate toxin production. Chlorate appears to be an effective method to reduce shiga toxin-producing E. coil (STEC) populations in food animals, but additional studies are warranted before it is used to control infections.

Animals↗
PubMedDate not supplied

[Optimization of cultivation conditions of chlorate-reducing bacteria Acinetobacter thermotoleranticus C-1 for treatment of sewage from fuel mixtures industry].

Composition of culture medium for cultivation of chlorate-reducing strain A. thermotoleranticus C-1 has been optimized with the purpose to decontaminate sewage from production of fuel mixtures, match production sewage, including toxical oxygen-containing anions-chlorates, chromates in particular. It has been established that chlorates are not toxical for the studied culture in a wide concentration range. The rate of chlorates reduction by the strain C-1 was 50.4 + 2.3 mg/(l x h). Maximum chlorate reduction displays in the medium containing (mg/1) : ClO3(-) - 700; CrO4(2-) - 4.5; phosphates in the form of HPO4(2-) - 0.5; in the form of H2PO4(-) - 4.5; nitrogen in the form of NH4Cl - 50.0; t - 40 degrees C; albumin - 500. It is shown that the optimal ratio ChPC:N:P in sewage supplied for neutralization should be 80:10:1 for the efficient use of the strain.

Acinetobacter↗
PubMed2005

The C subunit of Ideonella dechloratans chlorate reductase: expression, purification, refolding, and heme reconstitution.

The C subunit of Ideonella dechloratans chlorate reductase has been expressed in Escherichia coli as a GST fusion protein. Purification from inclusion bodies, followed by refolding and reconstitution with heme, produced a protein with a heme/protein ratio of 0.4, and with UV-vis spectral characteristics similar to those of native chlorate reductase. Wavelength maxima for the alpha and beta bands in the reduced state were 559 and 529 nm for both native chlorate reductase and the reconstituted recombinant subunit, whereas the reduced Soret bands were found at 426 and 424 nm, respectively. These results support the notion of the C subunit as the cytochrome b moiety of I. dechloratans chlorate reductase. Moreover, the availability of a recombinant version of the C subunit is expected to facilitate further studies of electron transfer and protein interaction included in the reaction catalyzed by chlorate reductase.

Bacterial Proteins↗
PubMed1999

Selective effects of sodium chlorate treatment on the sulfation of heparan sulfate.

We have analyzed the effect of sodium chlorate treatment of Madin-Darby canine kidney cells on the structure of heparan sulfate (HS), to assess how the various sulfation reactions during HS biosynthesis are affected by decreased availability of the sulfate donor 3'-phosphoadenosine 5'-phosphosulfate. Metabolically [(3)H]glucosamine-labeled HS was isolated from chlorate-treated and untreated Madin-Darby canine kidney cells and subjected to low pH nitrous acid cleavage. Saccharides representing (i) the N-sulfated domains, (ii) the domains of alternating N-acetylated and N-sulfated disaccharide units, and (iii) the N-acetylated domains were recovered and subjected to compositional disaccharide analysis. Upon treatment with 50 mM chlorate, overall O-sulfation of HS was inhibited by approximately 70%, whereas N-sulfation remained essentially unchanged. Low chlorate concentrations (5 or 20 mM) selectively reduced the 6-O-sulfation of HS, whereas treatment with 50 mM chlorate reduced both 2-O- and 6-O-sulfation. Analysis of saccharides representing the different domain types indicated that 6-O-sulfation was preferentially inhibited in the alternating domains. These data suggest that reduced 3'-phosphoadenosine 5'-phosphosulfate availability has distinct effects on the N- and O-sulfation of HS and that O-sulfation is affected in a domain-specific fashion.

Animals↗
PubMedDate not supplied

Phosphodiesterase III inhibitor olprinone chlorate is not significantly removed by continuous venovenous hemodiafiltration.

The study objective was to determine whether a phosphodiesterase III inhibitor, olprinone chlorate, is effectively removed by continuous venovenous hemodiafiltration (CVVHDF) in a patient with cardiac and renal failure. The patient was a 73 year old man who had undergone coronary artery bypass grafting for ischemic heart disease and who developed cardiac and renal failure postoperatively. A 0.2 microg/kg per minute dosage of olprinone chlorate was administered intravenously for 120 minutes while the patient was treated with CVVHDF. Samples from the arterial and venous blood catheters and those from the ultradiafiltrate for 12 hours were collected to calculate pharmacokinetic parameters and clearance of hemodiafiltration. The calculated parameters were as follows: half-life of elimination phase: 4.96 hours; total clearance 3.40 ml/min per kg. The clearance of CVVHDF was 0.33 ml/min per kg. The olprinone chlorate clearance of CVVHDF approximates only 10% of total clearance in this case. CVVHDF may not produce significant reduction in the serum olprinone chlorate level. It is recommended that the infusion dosage of olprinone chlorate should be reduced when given to patients with renal failure even if treated with CVVHDF.

Aged↗
PubMed1991

Anaerobic growth of microorganisms with chlorate as an electron acceptor.

The ability of microorganisms to use chlorate (ClO(3)) as an electron acceptor for respiration under anaerobic conditions was studied in batch and continuous tests. Complex microbial communities were cultivated anaerobically in defined media containing chlorate, all essential minerals, and acetate as the sole energy and carbon source. It was shown that chlorate was reduced to chloride, while acetate was oxidized to carbon dioxide and water and used as the carbon source for synthesis of new biomass. A biomass yield of 1.9 to 3.8 g of volatile suspended solids per equivalent of available electrons was obtained, showing that anaerobic growth with chlorate as an electron acceptor gives a high energy yield. This indicates that microbial reduction of chlorate to chloride in anaerobic systems is coupled with electron transport phosphorylation.

Journal Article↗
PubMed2003

Characterization of the chlorate reductase from Pseudomonas chloritidismutans.

A chlorate reductase has been purified from the chlorate-reducing strain Pseudomonas chloritidismutans. Comparison with the periplasmic (per)chlorate reductase of strain GR-1 showed that the cytoplasmic chlorate reductase of P. chloritidismutans reduced only chlorate and bromate. Differences were also found in N-terminal sequences, molecular weight, and subunit composition. Metal analysis and electron paramagnetic resonance measurements showed the presence of iron and molybdenum, which are also found in other dissimilatory oxyanion reductases.

Amino Acid Sequence↗
PubMed1995

Differential effects of a heparin antagonist (hexadimethrine) or chlorate on amphiregulin, basic fibroblast growth factor, and heparin-binding EGF-like growth factor activity.

Amphiregulin (AR) and heparin-binding EGF-like growth factor (HB-EGF) are two recently identified members of the EGF family. Both AR and HB-EGF share with EGF the ability to interact with the type-1 EGF receptor; however, AR and HB-EGF differ from EGF in that both of these mitogens bind to heparin while EGF does not. To determine whether interactions with heparin-like molecules on the cell surface influence binding of AR and HB-EGF with EGF receptors and the subsequent mitogenic activity exerted by these growth factors, murine AKR-2B and Balb/MK-2 cells were treated with either an inhibitor of proteoglycan sulfation (chlorate) or a heparin antagonist (hexadimethrine). As expected, neither treatment significantly altered the specific binding of 125I-EGF on AKR-2B cells. Interestingly, treatment with either chlorate or hexadimethrine inhibited the ability of AR to compete with 125I-EGF for cell surface binding and also attenuated AR-mediated DNA synthesis. Thus, as has been suggested for other heparin-binding growth factors such as basic fibroblast growth factor (bFGF), the interaction of AR with an EGF-binding receptor appears to be facilitated by interaction with cell-associated sulfated glycosaminoglycans or proteoglycans. Unexpectedly, however, neither chlorate nor hexadimethrine treatment caused an inhibition of HB-EGF-induced mitogenic activity. Chlorate treatment did not significantly alter the ability of HB-EGF to compete with 125I-EGF for cell surface binding sites, however, heparin and hexadimethrine reduced the ability of HB-EGF to compete for 125I-EGF binding. These results suggest that, in AKR-2B cells, HB-EGF may mediate its mitogenic response at least in part through a receptor which appears to be selective for HB-EGF and permits HB-EGF-mediated mitogenic responses in the presence of hexadimethrine or heparin. Finally, hexadimethrine inhibited the specific binding and mitogenic activity of bFGF, suggesting that this cationic polymer can function as an antagonist of heparin-binding mitogens other than AR.

Amphiregulin↗
PubMed1991

Substitute anions and the chloride conductance of frog muscle: effects of chlorate and bromate on steady-state values and kinetics.

Voltage-clamp experiments have been used to study the effects of external nitrate, chlorate and bromate on the chloride conductance of sarcolemma of Xenopus laevis. Nitrate reduces inward current (chloride efflux), but less potently than does thiocyanate [Vaughan (1987) Pflügers Arch 410:153-158] and does not affect conductance kinetics. As its concentration is increased the blocking effect of nitrate saturates; at a nitrate mole fraction of 0.6 the anion conductance is reduced to about 50% and further increases in nitrate concentration are without significant effect. Nitrate's influences are not voltage-dependent. Chlorate is a much less potent blocker than is nitrate, and its effects are voltage-dependent. With small hyperpolarizations, currents are sometimes seen to be larger than the control, but the degree of block (or the conversion of augmentation to reduction) increases with the size of the voltage step. Anomalous mole-fraction effects are observed in the range 0.4-0.6 mol/mol, in that in some cells the reduction of conductance is noticeably greater in the lower than in the higher concentration of the replacement ion. In the presence of chlorate, relaxation rates are significantly increased, and this influence is not anomalously dependent on the mole fraction. Similar effects are observed in bromate. The effect on kinetics is not pH-dependent. The main series of experiments was conducted at pH 5, but the same influence on kinetics was observed at pH 9. Using point voltage-clamp experiments, chlorate and thiocyanate were both seen to lower the contraction threshold voltage, but thiocyanate has no influence on conductance kinetics.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Erythrocyte membrane alterations as the basis of chlorate toxicity.

The effects of sodium chlorate and of sodium nitrite on human erythrocytes were studied in vitro. Nitrite rapidly oxidised haemoglobin and glutathione; reduction of methaemoglobin (Hbi) by methylene blue was complete during 3 h of incubation with nitrite. With chlorate, a concentration-dependent lag phase was seen before Hbi was formed. After prolonged incubation, Hbi could no longer be reduced with methylene blue. Several other effects were observed that explain the clinical picture of chlorate poisoning which involves haemolysis followed by disseminated intravascular coagulation and renal failure: increased permeability to cations, increased resistance to hypotonic haemolysis and prolonged filtration time through polycarbonate membranes with cylindrical pores of 5 micron diameter. This suggests an increased membrane rigidity due to membrane protein polymerisation, as demonstrated by SDS polyacrylamide gel electrophoresis. Simultaneously, erythrocyte enzymes were inactivated, primarily glucose-6-phosphate dehydrogenase which is necessary for the therapeutic effect of methylene blue. This explains the inefficacy of methylene blue in the treatment of a case of chlorate poisoning that we observed (Arch. Toxicol., 48 (1981) 281).

Chlorates↗
PubMed2005

Dechloromonas hortensis sp. nov. and strain ASK-1, two novel (per)chlorate-reducing bacteria, and taxonomic description of strain GR-1.

Recent studies on the occurrence of (per)chlorate-reducing bacteria have resulted in the characterization of strains capable of dissimilatory (per)chlorate reduction. Phylogenetic analysis has shown that these bacteria are members of the Proteobacteria. Strains have been isolated from polluted and pristine sites, but only strains from polluted sites have been characterized in detail and deposited in culture collections. Herein we describe the isolation and characterization of perchlorate-reducing bacterium strain MA-1(T) and chlorate-reducing bacterium strain ASK-1, respectively isolated from a pristine and a chlorate-polluted site. Both isolates are members of the Proteobacteria. The 16S rRNA gene sequence similarity of MA-1(T) to Dechloromonas agitata DSM 13637(T) is 97.6%, but the relatedness in DNA-DNA reassociation is only 37%. Therefore, we propose to classify strain MA-1(T) (=DSM 15637(T)=ATCC BAA-776(T)) as the type strain of a novel species, Dechloromonas hortensis sp. nov. Strain ASK-1 and a previously described strain GR-1 show 100 and 99% 16S rRNA gene sequence similarity to Pseudomonas chloritidismutans DSM 13592(T) and Dechlorosoma suillum DSM 13638(T), respectively. DNA-DNA hybridization studies indicated that strains ASK-1 and GR-1 are related at the species level to P. chloritidismutans DSM 13592(T) (79%) and Dechlorosoma suillum DSM 13638(T) (85%), respectively. As suggested previously, Dechlorosoma suillum appears to be a later heterotypic synonym of Azospira oryzae. Although strain ASK-1 is identified as P. chloritidismutans, its morphology and growth requirements are different from those of the type strain.

Chlorates↗
PubMed1990

The structure of hexaaquanickel(II) chlorate.

Hexaaquanickel(II) chlorate, [Ni(H2O)6]-(ClO3)2, Mr = 333.69, cubic, Pa3-, a = 10.3159 (5) A, V = 1097.80 (5) A3, Z = 4, F(000) = 680, Dx = 2.02 g cm-3, lambda(Mo K alpha-) = 0.71069 A, T = 296 K, mu = 23.13 cm-1, R = 0.026 for 388 unique reflections having I greater than sigma I. The single type of Ni ion is coordinated by six water-molecule O atoms, each at an observed distance 2.054 (1) A, in an almost regular octahedral array. The single type of chlorate ion has a Cl--O bond length 1.487 (1) A and O--Cl--O bond angle 106.45 (6) degrees. The Ni--O complex, but not the chlorate ion, manifested rigid-body behavior. The Ni--O distance corrected for rigid-body motion is 2.060 A. Location and refinement of the two inequivalent H atoms permitted a detailed analysis of hydrogen bonding, which occurs principally between the oxygen octahedra and the chlorate groups.

Chlorates↗
PubMed1980

Free-living and symbiotic characteristics of chlorate resistant mutants of Rhizobium.

This work investigated the usefulness of chlorate resistance as a method for the selection of nitrate reductase negative (NR-) strains from Rhizobium japonicum (61A76) and evaluated the symbiotic, characteristics of these strains. Chlorate resistent strains were selected from populations seeded on CS 7 agar containing 10 or 20 mM KC10, and incubated in 2% air- 98% N2-CO2 (95:5). Over 200 resistant strains were isolated, 58% of which lacked the dissimilatory nitrate reductase. In 12 selected isolates, some strains had also lost the assimilatory nitrate reductase, but all retained hydrogenase activity. Chlorate resistant strains inoculated to soybean seedlings were equal to or better than the parent strain in terms of nodule mass and acetylene reduction. Those strains lacking both assimilatory and dissimilatory nitrate reductase showed the best symbiotic characteristics, suggesting that chlorate resistance in R. japonicum could be a useful method for the selection of strains with superiod nitrogen-fixing characteristics.

Chlorates↗
PubMed1984

The effects of chlorate- and streptomycin-resistance mutations on nitrofurantoin resistance in Escherichia coli K-12.

Chlorate-resistant mutants with none of the usual pleiotropic effects such as defective nitrate reductase activity were isolated from Escherichia coli K-12. These chlorate-resistant mutants (designated chlHW) did not yield strains with a high level of nitrofurantoin resistance following selection with nitrofurantoin. The chlorate-resistance mutation reduced the nitrofurantoin resistance of high-level mutants to an intermediate level. Further mutation to resistance to streptomycin and other aminoglycoside antibiotics suppressed the effect of chlHW on the level of nitrofurantoin resistance. Other chlorate-resistance genes examined did not have the same effect on nitrofurantoin resistance as chlHW. The gene was cotransducible (Pl) with intermediate-level nitrofurantoin resistance and proC. It is suggested that the chlHW mutation may enhance the accumulation of nitrofurantoin inside the cell since it is known that a multiple aminoglycoside-resistance mutation with pleiotropic effects on the cell membrane can also confer high-level resistance to nitrofurantoin.

Chlorates↗
PubMed1988

The inhibition by chlorate of the sulphation of polyethyleneglycol in the isolated perfused guinea pig liver.

1. The sulphation of polyethyleneglycol 200 by the isolated perfused guinea pig liver is inhibited to about 60% by 10 mM ClO3- in the plasma of the perfusate when the concentration of SO4(2-) therein is 1.18 mM. 2. The inhibition is almost complete when the concentration of SO4(2-) is about 0.1 mM, a level which can be achieved by using a modified Ringer-bicarbonate solution, devoid of sulphate, to prepare the perfusate. 3. Chlorate, presumably through its action on ATP-sulphurylase, may therefore be a useful inhibitor of sulphation in the isolated perfused liver when the activity of the sulphurylase is rate-limiting. 4. The rate of bile production in the presence of chlorate is no different from that in its absence showing that, in the time scale of the perfusion, chlorate is not a general liver poison. 5. When the synthesis of PAPS is not rate-limiting, as in the sulphation of oestrone metabolites by rat liver, chlorate has no effect on the rate of sulphation.

Animals↗
PubMedDate not supplied

[Use of immobilized cells of bacteria in the process of purification of waste water containing chlorates and chromates].

Some regularities of immobilization of chlorate-reducing bacteria by various carriers and especially sewage treatment for chlorate and chromates by adhered bacteria have been studied. Most bacterial cells are immobilized during the first hour of contact with the carrier. The studied carriers, as to their ability to adsorb Aerococcus dechloraticans TGS-463 cells, may be arranged in the following sequence: porolon > claydite > glass broaches > maize stem > barley straw. The 12-24 hour culture Aerococcus dechloraticans TGS-463 expresses maximum ability to immobilization. The bacterial cell fastening on the carrier increases 2.1 times the reduction velocity for chlorates and 1.6 times that for chromates. The velocity of chlorates and chromates reduction by the culture factened on the carrier decreases in the due course of time, that requires the carrier regeneration.

Bacterial Adhesion↗
PubMedDate not supplied

Improved determination of chlorite and chlorate in rinse water from carrots and green beans by liquid chromatography and amperometric and conductivity detection.

A method is presented for determining chlorite and chlorate in the presence of interfering organic compounds in rinse water from vegetables. Rinse water from cut raw carrots and green beans was fortified separately with chlorite and chlorate, filtered (0.45 microns), and analyzed by liquid chromatography with amperometric and conductivity detection. Detection limits for chlorite and chlorate in carrot rinse water were 17 and 50 ppb, respectively. Average recoveries from rinse water were 95% for chlorite in a 0.084-1.00 ppm range and 90% for chlorate in a 0.078-1.00 ppm range.

Chlorates↗
PubMed2005

The chlorate-iodine clock reaction.

A clock reaction produced by mixing chlorate and iodine solutions in perchloric acid media is reported. This is the first example of a clock reaction using chlorate as a reagent. Increasing chlorate and acid concentration reduces the induction period. Changing the initial iodine concentration does not affect the length of the induction period. The discovery of this clock reaction opens the possibility that a new family of oscillation reactions can be built using chlorate as reagent.

Journal Article↗