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At least 127 records · Page 7Linked to original sources
PubMed1992

Impact of growth conditions on resistance of Klebsiella pneumoniae to chloramines.

The resistance of Klebsiella pneumoniae to inorganic monochloramine (1.5 mg/liter; 3:1 Cl2:N ratio, pH 8.0) was examined in relation to growth phase, temperature of growth, and growth under decreased nutrient conditions. Growth phase did not impact resistance to chloramines. Mid-exponential and stationary-phase cells, grown in a yeast extract-based medium, had CT99 values and standard deviations of 4.8 +/- 0.1 and 4.6 +/- 0.2 mg.min/liter, respectively. Growth temperature did not alter chloramine resistance at short contact times. CT99 values of cells grown at 15 and 23 degrees C were 4.5 +/- 0.2 and 4.6 +/- 0.2 mg.min/liter, respectively. However, at longer contact times, CT99.99 values of cells grown at 15 and 23 degrees C were 14 and 8 mg.min/liter, respectively, suggesting a small resistant subpopulation for cells grown at the lower temperature. Growth under decreased nutrient conditions resulted in a concomitant increase in resistance to chloramines. When K. pneumoniae was grown in undiluted Ristroph medium and Ristroph medium diluted by 1:100 and 1:1,000, the CT99 values were 4.6 +/- 0.2, 9.6 +/- 0.4, and 24 +/- 7.0 mg.min/liter, respectively. These results indicate that nutrient availability has a greater impact than growth phase or growth temperature in promoting the resistance of K. pneumoniae to inorganic monochloramine.

Chloramines↗
PubMed2005

Culture-independent techniques for rapid detection of bacteria associated with loss of chloramine residual in a drinking water system.

Chloramination is often the disinfection regimen of choice for extended drinking water systems. However, this process is prone to instability due to the growth of nitrifying bacteria. This is the first study to use alternative approaches for rapid investigation of chloraminated drinking water system instability in which flow cytometric cell sorting of bacteria with intact membranes (membrane-intact fraction) (BacLight kit) or with active esterases (esterase-active fraction) (carboxyfluorescein diacetate) was combined with 16S rRNA gene-directed PCR and denaturing gradient gel electrophoresis (DGGE). No active bacteria were detected when water left the water treatment plant (WTP), but 12 km downstream the chloramine residual had diminished and the level of active bacteria in the bulk water had increased to more than 1 x 10(5) bacteria ml(-1). The bacterial diversity in the system was represented by six major DGGE bands for the membrane-intact fraction and 10 major DGGE bands for the esterase-active fraction. PCR targeting of the 16S rRNA gene of chemolithotrophic ammonia-oxidizing bacteria (AOB) and subsequent DGGE and DNA sequence analysis revealed the presence of an active Nitrosospira-related species and Nitrosomonas cryotolerans in the system, but no AOB were detected in the associated WTP. The abundance of active AOB was then determined by quantitative real-time PCR (qPCR) targeting the amoA gene; 3.43 x 10(3) active AOB ml(-1) were detected in the membrane-intact fraction, and 1.40 x 10(4) active AOB ml(-1) were detected in the esterase-active fraction. These values were several orders of magnitude greater than the 2.5 AOB ml(-1) detected using a routine liquid most-probable-number assay. Culture-independent techniques described here, in combination with existing chemical indicators, should allow the water industry to obtain more comprehensive data with which to make informed decisions regarding remedial action that may be required either prior to or during an instability event.

Bacteria↗
PubMed2002

Occupational asthma caused by chloramines in indoor swimming-pool air.

The first series of three workers who developed occupational asthma following exposure to airborne chloramines in indoor chlorinated swimming pools is reported. Health problems of swimmers in indoor pools have traditionally been attributed to the chlorine in the water. Chlorine reacts with bodily proteins to form chloramines; the most volatile and prevalent in the air above swimming pools is nitrogen trichloride. Two lifeguards and one swimming teacher with symptoms suggestive of occupational asthma kept 2-hourly measurements of peak expiratory flow at home and at work, analysed using the occupational asthma system (OASYS) plotter, and/or had specific bronchial challenge testing to nitrogen trichloride, or a workplace challenge. Air measurement in one of the pools showed the nitrogen trichloride levels to be 0.1-0.57 mg x m(-3), which was similar to other studies. Two workers had peak expiratory flow measurements showing occupational asthma (OASYS-2 scores 2.88 and 3.8), both had a positive specific challenge to nitrogen trichloride at 0.5 mg x m(-3) with negative challenges to chlorine released from sodium hypochlorite. The third worker had a positive workplace challenge. Swimming-pool asthma due to airborne nitrogen trichloride can occur in workers who do not enter the water because of this chloramine. The air above indoor swimming pools therefore needs to be assessed and managed as carefully as the water.

Adult↗
PubMed2001

The influence of plasma on the disinfecting activity of the new antimicrobial agent N-chlorotaurine-sodium in comparison with chloramine T.

The phenomenon of increasing bactericidal activity of N-chlorotaurine in the presence of chlorine-consuming material has been investigated both on a chemical-analytical and microbiological basis using plasma as substrate and chloramine T for comparison. Chlorine consumption assessed by iodometric titration showed a biphasic time-course with a very fast loss of oxidation capacity within one minute (N-chlorotaurine: -9.3%, chloramine T: -16.8%) followed by a slow loss which could still be detected after 24 h (total loss -61.7% and -74.1%, respectively). Killing curves revealed that an increase in bactericidal activity, in spite of improved consumption, did not occur with all strains, and could be detected only at a certain degree of consumption. Escherichia coli and Pseudomonas aeruginosa showed the most pronounced effect, Streptococcus pyogenes and Proteus mirabilis a medium-sized one, while it was absent in Staphylococcus aureus. With chloramine T, an increase in bactericidal activity could not be proved. The chemical basis of these consumption effects can be reduced to four reaction types: oxidation of thiols; chlorine substitution of activated C-H compounds; transhalogenation; and hydrolytic degradation of N-chloro-alpha-amino acids and -peptides emerging by transhalogenation. The initial fast loss of oxidation capacity can be attributed mainly to oxidation of thiols, while the subsequent slower decrease is caused by the other types of reaction. The increase in bactericidal activity, on the other hand, can be explained by transhalogenation, leading to the formation of more bactericidal N-chloro compounds by which the loss of N-chlorotaurine is over-compensated.

Animals↗
PubMed1986

Quantitation and identification of organic N-chloramines formed in stomach fluid on ingestion of aqueous hypochlorite.

The chemical reactions that hypochlorite undergoes in the body when chlorinated water is ingested have received very little attention. Because amino nitrogen compounds are important components of the average diet, the reactions of hypochlorite with amino compounds in the stomach were investigated. Stomach fluid was recovered from Sprague-Dawley rats that had been fasted for 48 hr and administered 4 mL deionized water. The chlorine demand of the stomach fluid was determined. An average volume-independent demand of 2.7 mg chlorine was measured. At doses below 40 mg/L chlorine reducing reactions appeared to account for reduction of all oxidizing species within 15 min as measured by the FAS-DPD titrimetric method. At least part of the chlorine demand is associated with amino acids present in the stomach fluid. Amino acids were identified and quantified in the stomach fluid by precolumn derivatization with o-phthalaldehyde and high-pressure liquid chromatography (HPLC). When stomach fluid is chlorinated to concentrations of chlorine between 200 and 1000 mg/L, organic N-chloramines are formed. After derivatization of chlorinated stomach fluid with dansyl sulfinic acid, fluorescent derivatives of chloramines were separated by HPLC. Three chloramino acid derivatives, N-chloroalanine, N-chloroglycine, and N-chlorophenylalanine, were identified by cochromatography with known standards using two chromatographic methods. The yield of a chloramine that would form in stomach fluid on administration of hypochlorite to animals was determined using tritiated piperidine and doses of 200 and 1000 mg/L chlorine. Yields of tritiated N-chloropiperidine in recovered stomach fluid were 70% and 42%, respectively, of the theoretical amount expected.

Animals↗
PubMed1984

Radioimmunoassay of oxidized calmodulin in chloramine-T treated tissue samples.

We found that a short incubation of calmodulin with chloramine-T alters its antigenic structure. Antisera elicited by performic acid oxidized calmodulin only bind with chloramine-T treated calmodulin. Based on this finding we have developed an assay for the determination of calmodulin in small tissue samples. Tissue homogenates are incubated with 10 mmol/l chloramine-T before calmodulin quantification. Immune complexes are isolated by sodium sulphate precipitation. [125I]calmodulin is used as tracer.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1999

Chloramine and copper sulfate as control agents of planktonic larvae of Chironomus luridus in water supply systems.

The latest approach to control of midge larvae in drinking-water supplies is suppression of the planktonic 1st-stage larvae, by using 2 disinfectants, chloramine and copper sulfate. The median lethal concentration for 24-h exposure of the 1st-stage larvae of Chironomus luridus to chloramine and copper sulfate individually was 0.51 and 0.38 mg/liter, respectively. The increase of copper sulfate to 0.5 mg of copper per liter to water containing chloramine (0.5 mg/liter) created a synergistic reaction that resulted in 96% (+/-8% SD) mortality of the planktonic larvae. This treatment may serve as an effective control of 1st-stage larvae in municipal drinking-water supplies.

Animals↗
PubMed2001

Effects of antecedent fermentative and respiratory growth on the detection of chloramine-stressed Escherichia coil and Salmonella typhimurium.

In vitro laboratory studies were performed to assess the effects of antecedent growth conditions on the recovery of Escherichia coli ATCC 25922 and Salmonella typhimurium ATCC 14028 following chloramine disinfection. Six- and 18-h cultures of each organism were grown under aerobic, fermentative, and nitrate-reducing conditions prior to disinfection. At predetermined time intervals during a 10-min exposure to chloramine, survivors were surface plated on nonselective recovery media to determine C(n)t values. It was observed that nitrate-reducing growth predisposed the test organisms towards an increased sensitivity to chloramine stress over cells grown under fermentation or aerobic conditions (p < 0.01).

Aerobiosis↗
PubMed1992

[Characteristics of chloramine complexes of carnosine with hypochlorite anion].

Carnosine interaction with CIO results in the formation of a stable chloramine complex. The binding of the whole bulk of hypochlorite to carnosine is completed within one minute of incubation. During subsequent 2-hour incubation no more than 15% of the chloramine complex is destroyed; this property of carnosine makes it similar to taurine. Unlike histidine and beta-alanine, glutathione rapidly interacts with hypochlorite. However, in contrast with these compounds and carnosine, glutathione does not form stable chloramine complexes with CIO. The putative role of myeloperoxidase in the development of senile human lens opacities is discussed.

Animals↗
PubMedDate not supplied

[Mechanism of action of biogenic chloramines and hypochlorite on initial aggregation of blood platelets].

The antiaggregant action of two reactive oxidants N,N-dichlorotaurine (chloramine of biogenic type) and sodium hypochlorite on the initial ADP-induced aggregation of rabbit blood platelets has been studied. Platelet aggregation in the reconstructed platelet-rich plasma (PRP) was measured by the nephelometric method, and the aggregation index was an increase in the intensity of small-angle light scattering. The introduction of chloramine at comparatively small concentrations (no greater than 1 mM active chlorine) directly into the reconstructed platelet-rich plasma induces the suppression of the initial aggregation (formation of small aggregates) several times stronger than in the case of its preliminary incubation with plasma alone. This suggests that N,N-dichlorotaurine exerts its antiaggeregant action on the platelet-rich plasma by direct interaction with cells. The effects of the inhibition of platelet aggregation in two variants of introduction of high concentrations of N,N-dichlorotaurine do not significantly differ. In this case a great amount of residual chloramine remains in the plasma, which just induces the suppression of platelet aggregation during subsequent reconstruction of the platelet-rich plasma. Similar data have been obtained in the study of the antiaggregant action of hypochlorite. N,N-Dichlorotaurine and hypochlorite at final concentrations of 0.2-0.3 and 0.15 mM, respectively, inhibit strongly the initial aggregation of isolated platelets (approximately 2 x 10(8) cells in 1 ml) preliminarily activated for 1.5 min by the addition of 100-500 nM ADP. However, the antiaggregants show a more profound suppression of aggregation of unstimulated platelets. The antiaggregant effects of N,N-dichlorotaurine and hypochlorite are probably due to the oxidative modification of sulfur-containing groups in platelet plasmatic membrane.

Adenosine Diphosphate↗
PubMed1985

Comparison of radiochemical purity and tissue binding of labelled insulin prepared by lactoperoxidase and chloramine T iodination.

The radiochemical purity and tissue binding of 125I-insulin labelled by conventional chloramine T method were compared with those of (A14)-monoiodoinsulin prepared by lactoperoxidase iodination. In the first case the labelled insulin was purified on a cellulose column, while (A14)-monoiodoinsulin prepared with the aid of lactoperoxidase was purified on a column of QAE Sephadex A-25. After the digestion of labelled insulin by pronase about 15 percent of diiodoinsulin was found after chloramine T iodination, while a negligible amount (i.e. less than 1 percent) was detected after the use of lactoperoxidase. In addition, no damage of insulin molecules was found after the use of the latter method and the purification on QAE Sephadex A-25 yielded a homogenous preparation of insulin. Specific binding to isolated rat fat cells, rat liver plasma membranes and human erythrocytes was consistently higher in the case of (A14)-monoiodoinsulin compared to the insulin labelled by chloramine T method.

Adipose Tissue↗
PubMed1979

Heterogeneity of chloramine T- and lactoperoxidase-radioiodinated human calcitonin.

Radioiodination reportedly damages peptides, but the nature of the damage has not been adequately examined. Utilizing isoelectric focusing, we examined the products of Chloramine T- and lactoperoxidase-directed radioiodinations of human calcitonin. Initially, the reaction products were purified by adsorption onto and elution from microfine silica (QUSO-G32). Radioiodination of the calcitonin by Chloramine T and lactoperoxidase produced a heterogeneous population of 125I-labeled peptides exhibiting apparent isoelectric points that were more acidic than that of unlabeled synthetic calcitonin. Variation in the products among radioiodinations and the inability of QUSO-G32 to resolve the components of the reaction mixture prompted our examination of alternative purification procedures. Anion-exchange chromatography on QAE-Sephadex effectively separated [125I]diiodotyrosine containing calcitonin from free iodine and [125I]iodolactoperoxidase. Our data indicate that: (a) radioiodination of human calcitonin by Chloramine T and lactoperoxidase induced alteration in the peptide as evidenced by isoelectric point, (b) specific [125I]iodopeptides vary in incidence and relative abundance among radioiodinations, (c) identification of the labeled amino acid in [125I]iodopeptides cannot ensure intergrity of the molecule, and (d) isoelectric focusing provides a method of comparing the products of peptide radioiodinations among laboratories.

Calcitonin↗
PubMed1978

Preparation of iodine-125-labeled insulin for radioimmunoassay: comparison of lactoperoxidase and chloramine-T iodination.

The enzymatic radioiodination of porcine insulin by a system consisting of lactoperoxidase, hydrogen peroxide, and Na125I was compared with a modified chloramine-T technique. Satisfactory specific activity of the labeled hormone was obtained with the enzymatic iodination, with much greater immunoreactivity and stability than after chloramine-T, besides being quite suitable for the measurement of low plasma insulin levels. There was a positive and highly significant correlation between the insulin concentrations measured with the two tracers, with the regression line defined by the equation: y (chloramine-T) = 8.34 + 0.99 x (lactoperoxidase).

Animals↗
PubMedDate not supplied

[The anti-aggregatory effect of chloramine derivatives of amino acids on platelets in the presence of plasma].

Rabbit platelet aggregation induced by ADP is suppressed equally by the group of the chloramine derivatives of uncharged amino acid with the high molecular masses (N-chlorphenylalanine, N-chlorglutamine, N-chlorleucine). The effects of the derivatives of other uncharged amino acids are different, the inhibition degree increasing sharply at the decrease of molecular mass of amino acid chloramines. Ratio of the rate constant for the reaction of these chloramines with platelets and the rate constant for the reaction with plasma components raises exponentially at the molecular mass reduction.

Amino Acids↗
PubMed1998

[Sporicidal effect of Presept and Chloramine B on Bacillus cereus spores].

The sporicidal effect of Presept was compared with Chloramine B on the spores of Bacillus cereus. Either compound was calibrated to the same concentration of active chlorine. While a portion of spore population after 4 hrs of treatment by Chloramine germinated and started to divide in a rich nutrient medium, the optical density of the culture inoculated with spores treated by Presept did not increase even after 7 hrs when exposed to the nutrient medium. Significant morphological differences were found in either population of spores. Spores treated by Presept lost the impermeability within 3 hrs in the nutrient medium but almost no postgerminative development was observed. However, a portion of spores treated by Chloramine B developed after germination within 3 hrs into vegetative cells. It seems that Presept does not block germination and/or loss of impermeability of spores, but prevents their postgerminative development and division.

Bacillus cereus↗
PubMed2003

Use of an oxidation reaction for the quantitative determination of albendazole with Chloramine-T and acid dyes.

One titrimetric and two spectrophotometric procedures have been reported for the determination of albendazole and its tablets. Using titrimetry, the drug was titrated directly with Chloramine-T under acidic conditions using a Methyl Orange indicator. The spectrophotometric procedures involve treating the sample solution with a measured excess of Chloramine-T in an acid medium, followed by an estimation of unreacted Chloramine-T by reacting with a fixed amount of either Methyl Orange or Indigo Carmine dye solution and measuring the absorbance at 510 nm or 610 nm. The stoichiometric ratio, which forms the basis for the calculations in titrimetry as well as the range of the applicability, are reported. The Beer's law range and sensitivity values for spectrophotometric procedures are included. The methods were applied to the determination of albendazole in tablets with satisfactory results.

Albendazole↗
PubMed1987

Killing of schistosomula by taurine chloramine and taurine bromamine.

Eosinophils generate hypochlorous acid when stimulated with opsonized particles. The hypochlorous acid can react with beta-amino acids such as taurine to produce chloramines with a long lifetime. In the presence of bromide, eosinophils generate hypobromous acid which can react with taurine to generate taurine bromamine. As taurine is abundantly present in leukocytes, eosinophils have the potential to generate taurine chloramine or taurine bromamine. With regard to the role of eosinophils in killing schistosomula, we have shown that both taurine chloramine and taurine bromamine in physiological concentrations are able to kill the schistosomula of Schistosoma mansoni.

Animals↗
PubMed1996

Relative role of chloramines, hypochlorous acid, and proteases in the activation of human polymorphonuclear leukocyte collagenase.

The activation of collagenase released by polymorphonuclear leukocytes (PMNs) has been extensively studied in vitro, but the activation of the enzyme in vivo is not fully understood. For further evaluation of the relative role of oxidative and proteolytic mechanisms in the activation of collagenase, PMNs were stimulated by serum-opsonized zymosan under both aerobic and anaerobic conditions. The results showed that similar amounts of collagenase were released by the PMNs under aerobic and anaerobic conditions, but the activity of the released collagenase was twice as high under aerobic conditions as under anaerobic conditions. Under aerobic conditions the enzyme was rapidly activated by hypochlorous acid and chloramines, which are products of the myeloperoxidase-H2O2-chloride system of the PMNs. There was also a slow proteolytic activation of the enzyme, which could be ascribed to cathepsin G and possibly to some other serine proteases of PMNs. When extrapolating these findings to in vivo conditions, it seems probable that the oxidative activation of collagenase will proceed mainly by chloramines, which are more long-lived in the tissue than hypochlorous acid. In poorly oxygenated tissues, collagenase may be mainly activated by proteolytic mechanisms.

Adult↗