Posttranslational oxidative modification of (R)‐2‐(2,4‐dichlorophenoxy)propionate/α‐ketoglutarate‐dependent dioxygenases (RdpA) leads to improved degradation of 2,4‐dichlorophenoxyacetate (2,4‐D)

Microbial activities and the versatility gained through adaptation to xenobiotic compounds are the main biological forces to counteract environmental pollution. The current results present a new adaptive mechanism that is mediated through posttranslational modifications. Strains of Delftia acidovorans incapable of growing autochthonously on 2,4‐dichlorophenoxyacetate (2,4‐D) were cultivated in a chemostat on 2,4‐D in the presence of (R)‐2‐(2,4‐dichlorophenoxy)propionate. Long‐term cultivation led to enhanced 2,4‐D degradation, as demonstrated by improved values of the Michaelis–Menten constant K_m for 2,4‐D and the catalytic efficiency k_cat/K_m of the initial degradative key enzyme (R)‐2‐(2,4‐dichlorophenoxy)propionate/α‐ketoglutarate‐dependent dioxygenases (RdpA). Analyses of the rdpA gene did not reveal any mutations, indicating a nongenetic mechanism of adaptation. 2‐DE of enzyme preparations, however, showed a series of RdpA forms varying in their pI. During adaptation increased numbers of RdpA variants were observed. Subsequent immunoassays of the RdpA variants showed a specific reaction with 2,4‐dinitrophenylhydrazine (DNPH), characteristic of carbonylation modifications. Together these results indicate that posttranslational carbonylation modified the substrate specificity of RdpA. A model was implemented explaining the segregation of clones with improved degradative activity within the chemostat. The process described is capable of quickly responding to environmental conditions by reversibly adapting the degradative potential to various phenoxyalkanoate herbicides.     

Combination of high‐frequency ultrasound and UV radiation of excilamp for surface disinfection

The combination of high‐frequency ultrasound (HFUS) and UV represents a new approach to disinfecting surfaces. This study aimed to examine the inactivation efficiency of HFUS (1.7 MHz) and monochromatic UV radiation of KrCl excilamp (222 nm) in a single and a sequential mode against Bacillus cereus cells and spores added to glass surfaces. When treated by UV only, cells at populations of 10³, 10⁴, and 10⁵ colony‐forming units (CFU)/cm² showed 100% disinfection at high doses up to 1760 mJ/cm². Spores at 10⁴ CFU/cm² were completely inactivated at a dose of 1170 mJ/cm². Treatment with aqueous aerosol (produced by HFUS) reduced cell counts by 100% within a 40‐min exposure, whereas it was ineffective in inactivating spores under these conditions. In a sequential mode, the contaminated surface was pretreated with the sonicated aqueous aerosol and subsequently irradiated with the excilamp. It was found that HFUS exposure times and UV doses for complete inactivation decreased by a factor of 2 and 6–7, respectively, compared to sole HFUS or UV. A portable apparatus for surface disinfection was designed. The combined HFUS/UV method may be a promising technique for rapid disinfection of microbially contaminated surfaces.     

Fluorescence and bioluminescence analysis of sequential UV-biological degradation of p-cresol in water.

The photolysis and Penicillium tardum H-2 degradation of p-cresol in water containing humic acids was investigated by fluorescence and bioluminescence methods. Humic acids extracted from peat (the Vasuygan bog, Tomsk region of Russia) induce the phototransformation of p-cresol. The influence of humic acids on the phototransformation of p-cresol under different irradiation conditions was investigated. Comparison of the data on the KrCl* (lambda = 222 nm) and XeCl* (lambda = 308 nm) excilamps light showed that the most effective p-cresol degradation was observed with mercury lamp irradiation in the presence of humic acids.     

Combined effects of an oxidative enzyme and dissolved humic substances on 13C-labelled 2,4-D herbicide as revealed by high-resolution 13C NMR spectroscopy

Phenoxyalkanoic acids are a widely used class of herbicides. This work employed high-resolution ¹³C NMR to study the structural changes induced by humic substances and horseradish perodixase on 2,4-dichorophenoxyacetic acid (2,4-D) ¹³C-labelled in the side chain. NMR spectra showed that humic substances chemically catalyze abiotic splitting of [¹³C]2,4-D into 2,4-dichlorophenol and [¹³C]acetic acid at pH 7 but not at pH 4.7. Peroxidase did not catalyze the oxidative degradation of [¹³C]2,4-D at any pH tested and inhibited the effect of humic substances. Catalytic degradation by humic substances was attributed to free-radical reactions enhanced by the stereochemical contribution of large conformational structures formed by heterogeneous humic molecules at neutral pHs. Inhibition of 2,4-D degradation when humic substances were combined with peroxidase was explained by modification of both chemical and conformational humic structure due to peroxidase-promoted oxidative cross-coupling among humic molecules. Our findings show for the first time that the abiotic degradation of 2,4-D is catalyzed by dissolved humic substances at neutral pH. Journal of Industrial Microbiology & Biotechnology (2001) 26, 70–76. Received 09 February 2000/ Accepted in revised form 22 May 2000     

PARTICIPATION OF Y89 AND Y97 IN THE CONJUGATING ACTIVITY OF Drosophila melanogaster GLUTATHIONE S‐TRANSFERASE D3 (DmGSTD3)

Drosophila melanogaster glutathione S‐transferase D3 (DmGSTD3) has a shorter amino acid sequence as compared to other GSTs known in the fruit flies. This is due to the 15 amino acid N‐terminal truncation in which normally active amino acid residue is located. The work has made use of homology modeling to visualize the arrangement of amino acid side chains in the glutathione (GSH) substrate cavity. The identified amino acids were then replaced with amino acids without functional groups in the side chains and the mutants were analyzed kinetically. Homology modeling revealed that the side chains of Y89 and Y97 were shown facing toward the substrate cavity proposing their possible role in catalyzing the conjugation. Y97A and Y89A GSH gave large changes in K_m (twofold increase), V_max (fivefold reduction), and K_cat/K_m values for GSH suggesting their significant role in the conjugation reaction. The replacement at either positions has not affected the affinity of the enzyme toward 1‐chloro‐2,4‐dinitrobenzene as no significant change in values of K_max was observed. The replacement, however, had significantly reduced the catalytic efficiency of both mutants with (K_cat/K_m)^GSH and (K_cat/K_m)^CDNB of eight‐ and twofold reduction. The recombinant DmGSTD3 has shown no activity toward 1,2‐dichloro‐4‐nitrobenzene, 2,4‐hexadienal, 2,4‐heptadienal, p‐nitrobenzyl chloride, ethacrynic acid, and sulfobromophthalein. Therefore, it was evident that DmGSTD3 has made use of distal amino acids Y97 and Y89 for GSH conjugation.     

An easy‐to‐run method for routine analysis of eumelanin and pheomelanin in pigmented tissues

A procedure for analysis of melanin‐pigmented tissues based on alkaline hydrogen peroxide degradation coupled with high‐performance liquid chromatography (HPLC) ultraviolet determination of pyrrole‐2,3,5‐tricarboxylic acid (PTCA) for eumelanin and 6‐(2‐amino‐2‐carboxyethyl)‐2‐carboxy‐4‐hydroxybenzothiazole (BTCA) and 1,3‐thiazole‐2,4,5‐tricarboxylic acid for pheomelanin was recently developed. Despite advantages related to the degradation conditions and sample handling, a decrease of the reproducibility and resolution was observed after several chromatographic runs. We report herein an improved chromatographic methodology for simultaneous determination of PTCA and BTCA as representative markers of eumelanin and pheomelanin, respectively, based on the use of an octadecylsilane column with polar end‐capping with 1% formic acid (pH 2.8)/methanol as the eluant. The method requires conventional HPLC equipments and gives very good peak shapes and resolution, without need of ion pair reagents or high salt concentrations in the mobile phase. The intra‐assay precision of the analytical runs was satisfactory with CV values ≤4.0% (n = 5) for the two markers which did not exceed 8% after 50 consecutive injections on the column over 1 week. The peak area ratios at 254 and 280 nm (A₂₈₀/A₂₅₄: PTCA = 1.1, BTCA = 0.6) proved a valuable parameter for reliable identification of the structural markers even in the most complex degradation mixtures. The method can be applied to various eumelanin and pheomelanin pigmented tissues, including mammalian hair, skin and irides, and is amenable to be employed in population screening studies.     

Optimal rates of 2,4‐dichlophenoxyacetic acid foliar application for control of common scab in potato

Applications of the synthetic auxin 2,4‐dichlorophenoxyacetic acid (2,4‐D) to the foliage of potato plants can reduce common scab, a tuber disease. However, in prior research effective applications at 200 mg L^?1 2,4‐D resulted in phytotoxic side effects with reduced tuber yield and quality. This study showed that minimal significant threshold rates from 8.3 to 23.6 mg L^?1 2,4‐D reduced disease incidence in pot trials, and from 10.8 to 41.0 mg L^?1 minimised disease severity in both pot and field trials. In only one pot trial, significant phytotoxicity was found with rates of 100 mg L^?1 or greater, reducing mean total tuber mass per plot and 38 mg L^?1 or greater, reducing mean mass per tuber. Notably, within the field trial, a more reliable plant growth system for estimation of yield, no significant impacts were observed. Disease control was associated with decreased sensitivity of tubers to thaxtomin A, the phytotoxin produced by the common scab pathogen essential for disease induction. The amount of residual 2,4‐D in tubers at harvest varied with cultivar, Russet Burbank accumulating more 2,4‐D than Desiree. Application rates less than 100 mg L^?1 resulted in levels of 2,4‐D below the Australian standard maximum residue limit. These data suggest that applications of 2,4‐D at low rates could provide a commercially suitable control strategy for common scab.     

Comparison of DNA‐ and RNA‐based bacterial community structures in soil exposed to 2,4‐dichlorophenol

Aims: To examine the effect of the pollutant 2,4‐dichlorophenol on DNA‐ and RNA‐based bacterial communities in soil. Methods and Results: Soil was exposed to 100 mg kg^?1 of 2,4‐dichlorophenol (2,4‐DCP), and degradation was monitored over 35 days. DNA and RNA were coextracted, and terminal restriction fragment length polymorphism (T‐RFLP) was used to report changes in bacterial communities in response to the presence of the chlorophenol. The phylogenetic composition of the soil during degradation was determined by creating a clone library of amplified 16S rRNA sequences from both DNA and reverse‐transcribed RNA from exposed soil. Resulting clones were sequenced, and putative identities were assigned. Conclusions: A significant difference between active (RNA‐based) and total (DNA‐based) bacterial community structure was observed for both T‐RFLP and phylogenetic analyses in response to 2,4‐DCP, with more pronounced changes seen in RNA‐based communities. Phylogenetic analysis indicated the dominance of Proteobacteria in both profiles. Significance and Impact of the Study: This study describes the response of soil bacterial communities to the addition of the xenobiotic compound 2,4‐DCP, and highlights the importance of including RNA‐based 16S rRNA analysis to complement any molecular study in a perturbed soil.     

Spectrofluorimetric determination of aluminium using 2‐hydroxy‐1‐naphthylidene‐(8‐aminoquinoline)

A sensitive and selective spectrofluorimetric method has been developed for the rapid determination of aluminium. This method is based on the complex formation between aluminium and 2‐hydroxy‐1‐naphthylidene‐(8‐aminoquinoline) (HNAQ). The optimum conditions for the complex formation were a metal‐to‐ligand (M : L) stoichiometric ratio of 1:1, a pH of 5.5 and a 0.20 m acetate buffer. The fluorescence of the complex was monitored at an emission wavelength of 502 nm with excitation at 438 nm. Under these conditions, linear calibration curves were obtained in the ranges 0.05–1 and 1–5 ppm. The detection limit was 3.4 ppb for the former and 13.5 ppb for the latter. The maximum relative standard deviation of the method for an aluminium standard of 200 ppb was 1.5% (n = 5). This method was successfully applied for the determination of aluminium in drinking water, pharmaceutical antacid tablets and suspension samples. Copyright © 2010 John Wiley & Sons, Ltd.     

Small acidic protein 1 and SCFTIR1 ubiquitin proteasome pathway act in concert to induce 2,4‐dichlorophenoxyacetic acid‐mediated alteration of actin in Arabidopsis roots

2,4‐Dichlorophenoxyacetic acid (2,4‐D), a functional analogue of auxin, is used as an exogenous source of auxin as it evokes physiological responses like the endogenous auxin, indole‐3‐acetic acid (IAA). Previous molecular analyses of the auxin response pathway revealed that IAA and 2,4‐D share a common mode of action to elicit downstream physiological responses. However, recent findings with 2,4‐D‐specific mutants suggested that 2,4‐D and IAA might also use distinct pathways to modulate root growth in Arabidopsis. Using genetic and cellular approaches, we demonstrate that the distinct effects of 2,4‐D and IAA on actin filament organization partly dictate the differential responses of roots to these two auxin analogues. 2,4‐D but not IAA altered the actin structure in long‐term and short‐term assays. Analysis of the 2,4‐D‐specific mutant aar1‐1 revealed that small acidic protein 1 (SMAP1) functions positively to facilitate the 2,4‐D‐induced depolymerization of actin. The ubiquitin proteasome mutants tir1‐1 and axr1‐12, which show enhanced resistance to 2,4‐D compared with IAA for inhibition of root growth, were also found to have less disrupted actin filament networks after 2,4‐D exposure. Consistently, a chemical inhibitor of the ubiquitin proteasome pathway mitigated the disrupting effects of 2,4‐D on the organization of actin filaments. Roots of the double mutant aar1‐1 tir1‐1 also showed enhanced resistance to 2,4‐D‐induced inhibition of root growth and actin degradation compared with their respective parental lines. Collectively, these results suggest that the effects of 2,4‐D on actin filament organization and root growth are mediated through synergistic interactions between SMAP1 and SCF^TIR1 ubiquitin proteasome components.     

Validated spectrofluorimetric method for the determination of carbamazepine in pharmaceutical dosage forms after reaction with 4‐chloro‐7‐‐nitrobenzo‐2‐oxa‐1,3‐diazole (NBD‐Cl)

A sensitive and simple spectrofluorimetric method has been developed and validated for the determination of the anti‐epileptic drug carbamazepine (CBZ) in its dosage forms. The method was based on a nucleophilic substitution reaction of CBZ with 4‐chloro‐7‐nitrobenzo‐2‐ oxa‐1,3‐diazole (NBD‐Cl) in borate buffer (pH 9) to form a highly fluorescent derivative that was measured at 530 nm after excitation at 460 nm. Factors affecting the formation of the reaction product were studied and optimized, and the reaction mechanism was postulated. The fluorescence–concentration plot is rectilinear over the range of 0.6–8 µg/mL with limit of detection of 0.06 µg/mL and limit of quantitation of 0.19 µg/mL. The method was applied to the analysis of commercial tablets and the results were in good agreement with those obtained using the reference method. Validation of the analytical procedures was evaluated according to ICH guidelines. Copyright © 2015 John Wiley & Sons, Ltd.     

Infrared and visible emissions of rare‐earth‐doped CeO2 phosphor

This paper reports the synthesis and characterization of Er³⁺‐doped CeO₂ phosphor with variable concentrations of erbium. The sample was synthesized using a solid‐state reaction method, which is useful for the large‐scale production of phosphors and is also eco‐friendly. The prepared sample was characterized using an X‐ray diffraction (XRD) technique. The XRD pattern confirmed that sample has the pure cubic fluorite crystal structure of CeO₂. The crystallite size of the prepared phosphor was determined by Scherer's formula and the crystallite size giving an intense XRD peak is 40.06 nm. The surface morphology of the phosphor was determined by field emission gun scanning electron microscopy (FEGSEM). From the FEGSEM image, good surface morphology with some agglomerates was found. The functional group in the prepared sample was analysed by Fourier transform infrared (FTIR) spectroscopy. All samples prepared with variable concentrations of Er³⁺ (0.1–2 mol%) were studied by photoluminescence analysis and it was found that the excitation spectra of the prepared phosphor shows broad excitation centred at 251 nm. Emission spectra at different concentrations of Er³⁺ show strong peaks at 413 and 470 nm and a weaker peak at 594 nm. The dominant peaks at 413 and 470 nm are caused by the allowed electronic transition ⁴S_3/2 → ⁴I_15/2 and the weaker transition at 594 nm is due to the transition ⁴ F_9/2 → ⁴I_15/2. Spectrophotometric determinations of peaks were evaluated using the Commission Internationale de I'Eclairage (CIE) technique. The emission spectra were also observed using an infrared (IR) laser 980 nm source, and three distinct peaks were found in the IR region at 848, 870 and 980 nm. The prepared phosphor has utility for application in display devices. Copyright © 2015 John Wiley & Sons, Ltd.     

Nanowire‐Based Three‐Dimensional Transparent Conducting Oxide Electrodes for Extremely Fast Charge Collection

A 3D transparent conducting oxide (3D‐TCO) has been fabricated by growing Sn‐doped indium oxide (ITO) nanowire arrays on glass substrates via a vapor transport method. The 3D TCO charge‐collection properties have been compared to those of conventional two‐dimensional TCO (2D‐TCO) thin films. For use as a photoelectrode in dye‐sensitized solar cells, ITO‐TiO₂ core‐shell nanowire arrays were prepared by depositing a 45 nm‐thick mesoporous TiO₂ shell layer consisting of ～6 nm anatase nanoparticles using TiCl₄ treatments. Dye‐sensitized solar cells fabricated using these ITO‐TiO₂ core‐shell nanowire arrays show extremely fast charge collection owing to the shorter electron paths across the 45 nm‐thick TiO₂ shell compared to the 2D TCO. Interestingly, the charge‐collection time does not increase with the overall electrode thickness, which is counterintuitive to conventional diffusion models. This result implies that, in principle, maximum light harvesting can be achieved without hindering the charge collection. The proposed new 3D TCO should also be attractive for other photovoltaic applications where the active layer thickness is limited by poor charge collection.     

Inhibition effects of pesticides on glutathione‐S‐transferase enzyme activity of Van Lake fish liver

Glutathione‐S‐transferases (GSTs) have a function in xenobiotic metabolism. They are a significant multifunctional family with a wide variety of catalytic activities. In the current study, we determined in vitro inhibition effects of 2,4‐dichlorophenoxyacetic acid dimethylamine salt (2,4‐D DMA), haloxyfop‐P‐methyl, glyphosate isopropylamine, dichlorvos, and λ‐cyhalothrin on purified GST. For this purpose, GST were purified from Van Lake fish (Chalcalburnus tarichii Pallas) liver with 29.25 EU mg^?1 specific activity and 10.76% yield using GSH–agarose affinity chromatographic method. The pesticides were tested at various concentrations on in vitro GST activity. K_i constants were calculated as 0.17 ± 0.01, 0.25 ± 0.05, 3.72 ± 0.32, 0.42 ± 0.06, and 0.025 ± 0.004 mM, for 2,4‐D DMA, haloxyfop‐P‐methyl, glyphosate isopropylamine, dichlorvos, and λ‐cyhalothrin, respectively. λ‐Cyhalothrin showed a better inhibitory effect compared to the other pesticides. The inhibition mechanisms of λ‐cyhalothrin were competitive, while the other pesticides were noncompetitive.     

Novel α‐ketoglutarate dioxygenase tfdA‐related genes are found in soil DNA after exposure to phenoxyalkanoic herbicides

Phenoxyalkanoic herbicides such as 2,4‐dichlorophenoxyacetate (2,4‐D), 2,4‐dichlorophenoxybutyrate (2,4‐DB) or mecoprop are widely used to control broad‐leaf weeds. Several bacteria have been reported to degrade these herbicides using the α‐ketoglutarate‐dependent, 2,4‐dichlorophenoxyacetate dioxygenase encoded by the tfdA gene, as the enzyme catalysing the first step in the catabolic pathway. The effects of exposure to different phenoxyalkanoic herbicides in the soil bacterial community and in the tfdA genes diversity were assessed using an agricultural soil exposed to these anthropogenic compounds. Total community bacterial DNA was analysed by terminal restriction fragment length polymorphism of the 16S rRNA and the tfdA gene markers, and detection and cloning of tfdA gene related sequences, using PCR primer pairs. After up to 4 months of herbicide exposure, significant changes in the bacterial community structure were detected in soil microcosms treated with mecoprop, 2,4‐DB and a mixture of both plus 2,4‐D. An impressive variety of novel tfdA gene related sequences were found in these soil microcosms, which cluster in new tfdA gene related sequence groups, unequally abundant depending on the specific herbicide used in soil treatment. Structural analysis of the putative protein products showed small but significant amino acid differences. These tfdA gene sequence variants are, probably, required for degradation of natural substrate(s) structurally related to these herbicides and their presence explains self‐remediation of soils exposed to phenoxyalkanoic herbicides.     

Convenient preparation of deuterium‐labeled analogs of peptides containing N‐substituted glycines for a stable isotope dilution LC‐MS quantitative analysis

N‐substituted glycines constitute mimics of natural amino acids that are of great interest in the peptide‐based drug development. Peptoids‐oligo(N‐substituted glycines) have been recently demonstrated to be highly active peptidomimetics in biological systems, resistant to proteolytic degradation. We developed a method of the deuterium labeling of peptidomimetics containing N‐substituted glycine residues via H/D exchange of their α‐carbon hydrogen atoms. The labeling was shown to be easy, inexpensive, and without the use of derivatization reagents or the need for a further purification. The deuterons introduced at the α‐carbon atoms do not undergo a back exchange under acidic conditions during liquid chromatography mass spectrometry (LC‐MS) analysis. The LC‐MS analysis of a mixture of isotopologues revealed a co‐elution of deuterated and nondeuterated forms of the peptidomimetics, which may be useful in the quantitative isotope dilution analysis of peptoids and other derivatives of N‐substituted glycines. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.     

Axially chiral N‐(o‐aryl)‐4‐hydroxy‐2‐oxazolidinone derivatives from diastereoselective reduction of N‐(o‐aryl)‐2,4‐oxazolidinediones: Thermally interconvertible atropisomers via ring‐chain‐ring tautomerization

The reduction of the axially chiral N‐(o‐aryl)‐5,5‐dimethyl‐2,4‐oxazolidinediones by NaBH₄ yielded axially chiral N‐(o‐aryl)‐4‐hydroxy‐5,5‐dimethyl‐2‐oxazolidinone enantiomers having a chiral center at C‐4, with 100% diastereoselectivity as has been shown by their ¹H and ¹³C NMR spectra and by enantioselective HPLC analysis. The resolved enantiomeric isomers were found to interconvert thermally through an aldehyde intermediate formed upon ring cleavage via a latent ring‐chain‐ring tautomerization. It was found that the rate of enantiomerization depended on the size and the electronic effect of the ortho substituent present on the aryl ring bonded to the nitrogen of the heterocycle. Chirality 2010. © 2009 Wiley‐Liss, Inc.     

Effect of maternal diet rich in omega‐6 and omega‐9 fatty acids on the liver of LDL receptor‐deficient mouse offspring

BACKGROUND: Omega‐6 fatty acids are important to fetal development. However, during gestation/lactation, these fatty acids may contribute toward the development of fat tissue. Omega‐9 fatty acids are associated with a reduction in serum lipids and protection from liver disease. OBJECTIVES: The present study investigated the effect of the maternal intake of omega‐6 and omega‐9 in hypercholesterolemic mothers on the liver of the offspring. METHODS: LDL receptor–deficient mice were fed a diet rich in either omega‐6 (E6D) or omega‐9 (E9D) for 45 days prior to mating and until the birth of the offspring, evaluating the effect on the offspring liver in comparison to a standard diet (STD). RESULTS: Mothers fed with the E6D experienced an increase in total cholesterol (TC) and the offspring exhibited an increase in TC, hepatic triglycerides (TG), and CC‐chemokine ligand (CCL)2/monocyte chemoattractant protein (MCP)‐1 as well as a reduction in HDL. Histological analysis on this group revealed steatosis, leukocyte infiltrate, and increased CCL2/MCP‐1 expression. The ultrastructural analysis revealed hepatocytes with lipid droplets and myofibroblasts. The offspring of mothers fed the standard diet exhibited low serum TC, but microvesicular steatosis was observed. The offspring of mothers fed the E9D exhibited lower serum and hepatic TG as well as higher LDL in comparison to the other diets. The histological analyses revealed lower steatosis and leukocyte infiltrate. CONCLUSIONS: The findings suggest that hypercholesterolemic mothers with a diet rich in omega‐6 fatty acids predispose their offspring to steatohepatitis, whereas a diet rich in omega‐9 has a protective effect. Birth Defects Res (Part B) 89:164–170, 2010. © 2010 Wiley‐Liss, Inc.     

Evaluation of trapping parameters of γ‐rays irradiated Dy3+‐doped LaPO4 phosphors

Thermoluminescence (TL) materials are widely used in radiation measurements. The best‐known applications of TL materials are in the dosimetry of ionizing radiation, and in CTV screen phosphors, scintillators, X‐ray laser materials, etc. The TL glow curve and its kinetic parameters for annealed LaPO₄ at different constant temperatures and for Dy³⁺‐doped LaPO₄ phosphors irradiated by gamma‐rays are reported here. The samples were irradiated using a ⁶⁰Co gamma‐ray source at a dose of 10 Gy and the heating rate used for TL measurements was 5ºC/s. The samples were characterized using X‐ray diffraction (XRD), Fourier transform infrared, transmission electron microscopy and TL techniques. The XRD pattern shows that the prepared phosphor has a good crystalline structure with an average crystallite size of ~ 18 nm. The samples show good TL peaks for 0.05, 0.1 and 0.2 mole % doping concentrations of Dy³⁺ ions and anneal above 400ºC. The TL glow curve characteristics of annealed LaPO₄ and Dy³⁺‐doped LaPO₄ were analyzed and trapping parameters calculated using various methods. All TL glow curves obey the second‐order kinetics with a single glow peak, which reveals that only one set of trapping parameter is set for a particular temperature. The TL sensitivity was found to depend upon the annealing temperature and Dy³⁺ doping concentration. The prepared sample may be a new nano phosphor and be useful in TL dosimetry. Copyright © 2014 John Wiley & Sons, Ltd.