Effects of di-n-butyl phthalate on male rat reproduction following pubertal exposure

Di-n-butyl phthalate （DBP） is an endocrine-disrupting chemical that has the potential to affect male reproduction. However, the reproductive effects of low-dose DBP are still not well known, especially at the molecular level. In the present study, pubertal male Sprague-Dawley rats were orally administered DBP at a wide range of doses （0.1, 1.0, 10, 100 and 500 mg kg^-1 day^-1） for 30 days. The selected end points included reproductive organ weights, testicular histopathology and serum hormonal levels. Additionally, proteomic analysis was performed to identify proteins that are differentially expressed as a result of exposure to DBP at low doses （0.1, 1.0 and 10 mg kg^-1 day^-1）. Toxic effects were observed in the high-dose groups, including anomalous development of testes and epididymides, severe atrophy of seminiferous tubules, loss of spermatogenesis and abnormal levels of serum hormones. Treatment with low doses of DBP seemed to exert a ＇stimulative effect＇ on the serum hormones. Proteomics analysis of rat testes showed 20 differentially expressed proteins. Among these proteins, alterations in the expression of HnRNPA2/B1, vimentin and superoxide dismutase 1 （SOD1） were further confirmed by Western blot and immunohistochemistry. Taken together, we conclude that high doses of DBP led to testicular toxicity, and low doses of DBP led to changes in the expression of proteins involved in spermatogenesis as well as changes in the number and function of Sertoli and Leydig cells, although no obvious morphological changes appeared. The identification of these differentially expressed proteins provides important information about the mechanisms underlying the effects of DBP on male rat reproduction.

Removal of a type of endocrine disruptors—di-n-butyl phthalate from water by ozonation

Ozonation of synthetic water containing a type of endocrine disruptor-di-n-butyl phthalate （DBP） was examined. Key impact factors such as pH, temperature, ionic strength, ozone dosage and initial DBP concentration were investigated. In addition, the activities of radicals on uncatalysed and catalysed ozonation were studied. The degradation intermediate products were followed and the kinetic of the ozonation were assessed as well. Results revealed that ozonation of DBP followed two mechanisms. Firstly, the reaction rate of direct ozonation was slower at lower pH, temperature, and ionic strength. Secondly, when these factors were increased for indirect radical reaction, higher percentage of DBP was removed with the increase of the initial ozone dosage and the decrease of the initial DBP concentration. In addition, tea-butanol, humic substances and Fe（Ⅱ） affected DBP ozonation through the radical pathway. It was determined that ozonation was restrained by adding tea-butanol for its radical inhibition effect. Furthermore, humic substances enhanced the reaction to some extent, but a slight negative effect would be encountered if the optimum dosage was exceeded. As a matter of fact, Mn（Ⅱ） affected the ozonation by ＂active sites＂ mechanism. In the experiment, three different kinds of intermediate products were produced during ozonation, but the amount of products for each one of them decreased as pH, temperature, ionic strength and initial ozone dosage increased. A kinetic equation of the reaction between ozone and DBP was obtained.

Aerobic biodegradation of di-n-butyl phthalate by Xiangjiang River sediment and microflora analysis

Di-n-butyl phthalate (DBP),one of phthalate acid esters (PAEs),was investigated to determine its biodegradation rate using Xiangjiang River sediment and find potential DBP degraders in the enrichment culture of the sediment. The sediment sample was incubated with an initial concentration of DBP of 100 mg/L for 5 d. The biodegradation rate of DBP was detected using HPLC and the degraded products were analyzed by GC/MS. Subsequently,the microbial diversity of the enrichment culture was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results reveal that almost 100% of DBP is degraded after merely 3 d,generating two main degraded products:mono-butyl phthalate (MBP) and 9-octadecenoic acid. After a six-month enrichment period under the pressure of DBP,the dominant family in the final enrichment culture is clustered with the Comamonas sp.,the remaining are affiliated with Sphingomonas sp.,Hydrogenophaga sp.,Rhizobium sp.,and Acidovorax sp. The results show the potential of these bacteria to be used in the bioremediation of DBP in the environment.

Biodegradation Characteristics of Environmental Endocrine Disruptor Di-n-butyl Phthalate

Objective The biodegradation characteristics of di-n-butyl phthalate (DBP), an environmental endocrine disruptor, were studied by the method of dominant bacteria and immobilized microorganisms. Methods Taking DBP as the only carbon source to acclimatize the collected activated sludge, the concentration of DBP increased progressively in the process of acclimatization. Plate streaking was used to separate 1 strain of the degradation dominant bacteria after acclimatization. Better conditions to degrade DBP by the bacterium could be obtained through orthogonal experiments and the bacterium was identified. Then the acclimated activated sludge was made to immobilize the microorganism using polyvinyl alcohol as entrapment agent. The immobilized microorganism degraded DBP at different conditions. Results The appropriate conditions to degrade DBP by the dominant bacteria were: degradation time, 32 h; DBP concentration, 200 mg/L; rate of shaking incubator, 100 r/min; pH, 7 and temperature, 30℃. DBP could be degraded by more than 95% under such conditions. The bacteria were identified as pseudomonas. The proliferated immobilized microorganisms degraded DBP more effectively and more adapted to temperature and pH than the free acclimated activated sludge. Conclusion One strain of DBP degradation dominant bacteria was separated from the acclimatized activated sludge. It could grow with DBP as the only carbon source and energy, and degraded DBP effectively. After having been immobilized and proliferated, the dominant bacteria could keep a higher biological activity and degrade DBP more effectively than activated sludge.

Synthesis,Crystal Structure and Biological Activities of Novel Di-n-butyl Tin Di-carboxylate

A novel macrocyclic complex 2{[（n-Bu2Sn）4O2-L2]2DMF} was synthesized by the reaction of 4-（1,2- dithioethylene）methylene-3,5-disoxo-1,6-heptadiene-1,7-dis-（o-formy~）-dis-p-phenoxyacetic acid（LH2, compound 1） with di-n-butyltin oxide. Compound 1 and complex 2 were characterized by elemental analysis, FTIR spectroscopy, and ~H NMR spectroscopy. The crystal structure of complex 2 was determined by single crystal X-ray diffraction analysis. There are two crystallographic independent molecules in complex 2, and each molecule structure is centro-symmetric and features a central rhombus cyclic Bu4Sn2O2 unit with two exocyclic Sn atoms linked at the O atoms of the four-membered ring. In molecule A, the four Sn atoms are five-coordinated. However, in molecule B, the four Sn atoms have two different coordination geometries, the endocyclic Sn atoms are five-coordinated and the exocyclic Sn atoms are four-coordinated. The dicarboxylate ligands in molecules A and B bridge exocylic or endocyclic tin atoms, forming two macroheterocycles with 26 atoms. Pilot studies have indicated that complex 2 has good anti- bacterial and antitumour activities.

Vapor Pressures of Di-n-Butyl Phthalate and Di-iso-Butyl Hexahydrophthalate at Reduced Pressures

In this paper the measured values of the vapor pressures by ebulliometer method of two important maleic anhydride recovery solvents, di-n-butyl phthalate (DBP) and di-iso-butyl hexahydrophthalate (DIBE), between 0.63—17.79 kPa and 0.49—30.95 kPa,are reported respectively.A comparison of the data of DBP with the published data has been made, which shows good consistency. For the convenient use of these vapor pressures, Cragoe equation, Antoine equation and Kirchhoff equation are selected to correlate them. The correlating results show that Antoine equation is the best one of the three equations to fit for the vapor pressures of the two solvents. According to Clausius-Clapeyron equation, the linear relationship between natural logarithm of pressure and reciprocal of temperature is used to calculate the molar latent heats of evaporation of the two organic solvents. The molar latent heats of evaporation of DBP and DIBE are 75.1 kJ/mol and 67.7 kJ/mol, respectively.

Determination of Di-n-Butyl Phosphate in Organic Streams of FBTR Mixed Carbide Fuel Reprocessing Solution by Gas Chromatographic Technique

The present work describes the amount of Di-n- butyl phosphate (DBP) produced when PUREX solvent (30%tri-n-butyl phosphate (TBP) mixed with 70% hydrocarbon diluent) is exposed to intensive radiolytic and chemical at- tack during the separation of uranium and plutonium from fission products of FBTR mixed carbide fuel reprocessing solution. DBP is the major degradation product of Tri-n-butyl phosphate (TBP). Amount of DBP formed in the lean organic streams of different fuel burn-up FBTR carbide fuel reprocessing solutions were analyzed by Gas Chromatographic technique. The method is based on the preparation of diazo methane and conversion of non-volatile Di-n-butyl phosphate in to volatile and stable derivatives by the action of diazomethane and then determined by Gas Chromatography (GC). A calibration graph was made for DBP over a concentration in the range from 200 to 1800 ppm with correlation coefficient of 0.99587 and RSD 1.2%. The degraded 30% TBP-NPH solvent loaded with heavy metal ions like uranium was analyzed after repeated use and results are compared with standard ion chromatographic technique. A column comparison study to select of proper gas chromatographic column for the separation of DBP from other components in a single aliquot of injection is also examined.

邻苯二甲酸二丁酯的收缩血管作用及其机制

目的研究邻苯二甲酸二丁酯（di—n—butylphthalate，DBP）对大鼠动脉血管的作用，并探讨其可能机制。方法采用离体大鼠胸主动脉环灌流模型，观察DBP对动脉血管的收缩效应及其内皮的参与l生，并观察相关信号途径工具药的影响。结果DBP（10^-5-10-mol·L^-1）浓度依赖性收缩血管环，且去内皮血管比内皮完整血管收缩更明显（P〈0．05）；无Ca2＋“液中，DBP（10^-3mol·L^-1）引起的去内皮血管收缩明显低于正常K-H液中的血管收缩（P〈0．01），与对照组比较无差异；维拉帕米（10^-7mol·L^-1）预处理后，DBP（10^-3mol·L^-1）引起的血管环收缩幅度低于单用DBP组（P〈0．01）；一氧化氮合酶抑制剂左旋硝基精氨酸甲酯（L-NAME，10^-6mol·L^-1）预处理内皮完整主动脉环，引起的血管收缩幅度明显高于单用DBP组（P〈0．01），而前列环素合成酶抑制剂吲哚美辛（Indo，10^-5mol·L^-1）预处理对血管收缩幅度无明显影响。结论DBP具有引起血管收缩作用，初步机制可能涉及细胞膜电压门控性钙通道及钙离子内流，NO可能参与DBP的血管反应过程。

Combined Effects of Dibutyl Phthalate (DBP) and Benzo(a)Pyrene on Fertility in Male Rats

Our previous studies revealed the polycyclic aromatic hydrocarbon and phthalic acid esters were the major organic pollutants in the Jialing River and Yangtze River in the Three Gorges area, and they might cause the toxicity in male fertility when combined. Thus we used di-n-butyl phthalate (DBP) and Benzo(a)pyrene (Bap) as their representatives respectively to explore their effects on the spermatogenesis in male rats. Male Sprague Dawley rats were randomly divided into 4 groups and respectively exposed to corn oil, Bap (5 mg/kg/d), DBP (250 mg/kg/d), and combined doses of Bap (5 mg/kg/d) and DBP (250 mg/kg/d) for 90 days. We observed a significant increase in the stillbirth rate after Bap and combined treatments, while the mean area of seminiferous tubules was reduced after Bap, DBP and combined treatments. Bap and combined treatment had a sup- pressing effect on meiosis in germ cells, which reduced the haploid contents and the ratio between haploid and diploid but increased the tetraploid and diploid contents and the ratio between hap- loid and tetraploid. These effects were more obvious in the combined group. Furthermore, the ex- pression of a number of proteins was changed, of which was associated with the oxidative stress and cAMP/PKA signaling pathway. Our results suggest that Bap has significant toxic effects on male fertility, while the combined treatment of Bap and DBP has more toxic effects.

Elevated degradation of di-n-butyl phthalate by activating peroxymonosulfate over GO-CoFe_(2)O_(4)composites:Synergistic effects and mechanisms

Rational design of heterogeneous catalysts with high activity and stability is crucial in peroxymonosulfate(PMS)-based oxidation treatment of wastewater.Herein,the graphite oxide-cobalt ferrite(GOCoFe_(2)O_(4))composite was constructed,and its morphological,component and structural characteristics were thoroughly examined,respectively.GO-CoFe_(2)O_(4)obviously boosted PMS catalytic performance on di-n-butyl phthalate removal(DBP,RpBp=90%,Roc=37%),which indicated by the first-order kinetic constant(kpBp=0.060 min^(-1))being roughly 4 times than pure CoFe_(2)O_(4)(kpBp=0.015 min-1).The fabrication of GO-CoFe_(2)O_(4)brought the favorable stability and repeatability up to six cycles.Moreover,the method of batch dosing catalyst was creatively proposed to improve the PMS utilization efficiency.The coupling of GO enhanced the dispersion of CoFe_(2)O_(4)particles to obtain sufficient active sites,additionally,the plentiful C=O groups and free-flowing electrons on GO promoted GO-CoFe_(2)O_(4)to coordinate a redox process during PMS activation.With the aid of theoretical calculations,GO-CoFe_(2)O_(4)was revealed to exhibit a strong affinity toward PMS adsorption,where PMS spontaneously dissociated into sulfate radical(SO_(4)^(·-)),hydroxyl radical(^(·)OH)and singlet oxygen(^(1)O_(2)),acting as the reactive oxygen species(ROSs).Electrons cycling between Co,Fe and O species ensured continuous ROSs generation and excellent catalytic performance.

Unveiling the Nexus the link between water quality index and phthalic acid ester concentrations in Tigris River

Monitoring water quality in an aquatic system is a crucial objective in pursuing sustainable development,despite the challenges posed by water scarcity and the impact of climate change.The objective of the present study was to examine the water quality of the Tigris River along its course from the point of entry into Baghdad city to its exit,particularly in the presence of Phthalic Acid Esters(PAEs).In both dry and wet seasons and from five sites of the river,nine environmental factors(Turbidity,Total dissolved solids,pH,dissolved oxygen,Chloride,nitrate,phosphate,sulfate,and Biological oxygen demand)and three PAEs(di-n-butyl phthalate(DBP),di-isononyl phthalate(DiNP),and di-2-ethyl hexyl phthalate(DEHP))were investigated.Results revealed that the river has high levels of turbidity and Total dissolved solids,slightly alkaline,and well-aerated(dissolved oxygen>7 mg/L).Chloride,nitrate,phosphate,and sulfate values varied between seasons,as high values were recorded in the wet season.Biochemical oxygen demand levels were higher during the dry season.The highest value of total PAEs(2.20μg/L)was observed during the dry season,and the lowest value was in the wet season(1.16μg/L).The HQ results revealed that the river was ranked as a moderate risk area.However the water quality index and environmental risk index classified the water quality as a poor category,with a high-risk score in the study sites within Baghdad city.Therefore,despite the acceptable limit of PAEs in the river's water(<3μg/L),its presence is an early alarm to withdraw attention to its environmental risk.These findings highlight the need for appropriate measures to control and remove pollutants to ensure a safe and healthy water supply in the Tigris River.

Phytotoxicity in seven higher plant species exposed to di-n-butyl phthalate or bis （2-ethylhexyl） phthalate

We investigated phytotoxicity in seven plant species exposed to a range of concentrations （0- 500 mg· kg^-1 soil） of di-n-butyl phthalate （DnBP） or his （2- ethylhexyl） phthalate （DEHP）, two representative phthalate esters （PAEs） nominated by USEPA as priority pollutants and known environmental estrogens. We studied seed germination, root elongation, seedling growth, biomass （fresh weight, FW） and malondialdehyde （MDA） content of shoots and roots of wheat （Triticum aestivum L.）, alfalfa （Medicago sativa L.）, perennial ryegrass （Lolium perenne）, radish （Raphanus sativus L.）, cucumber （Cucumis sativus L.）, oat （Avena sativa） and onion （Allium cepa L.）, together with monitoring of plant pigment content （chlorophyll a, b and earotinoids） in alfalfa, radish and onion shoots. Root elongation, seedling growth and biomass of the test species were generally inhibited by DnBP but not by DEHP, indicating a lower level of phytotoxicity of DEHP than of DnBP. MDA contents of four species were promoted by PAE exposure, but not in alfalfa, ryegrass or onion shoots, indicating lower sensitivity of these three species to PAE pollutants. Plant pigment contents were clearly affected under the stress of both pollutants, implying the potential damage to the photosynthetic system of test plants, mainly by decreasing the content of chlorophyll a and b. Results of DnBP and DEHP phytotoxicity to the primary growth of test plants has provided information for the assessment of their environmental risk in the soil and also forms a basis for the further analysis of their toxic effects over the whole growth period of different plant species.

Uptake and accumulation of di-n-butyl phthalate in six leafy vegetables under hydroponic conditions

The uptake and accumulation of di-n-butyl phthalate(DBP)in six leafy vegetables was investigated under hydroponic conditions.The test vegetables were six varieties of Brassica campestris ssp.,including Kangresijiqing(KRSJQ),Xiadiqing(XDQ),Ziyoucai(ZYC),Aijiaohuang(AJH),Shanghaiqing(SHQ)and Gaogengbai(GGB).The root concentration factor(RCF),translocation factor(TF)and transpiration stream concentration factor(TSCF)were calculated in order to compare the difference of uptake and accumulation behaviours of DBP in vegetable varieties.The results showed that DBP was easily concentrated in vegetable roots,but was poorly translocated from the roots to the shoots.Among the six vegetables,the ability of concentrating DBP from the solution to shoots was the highest in GGB,followed by ZYC,KRSJQ,AJH,SHQ and XDQ.High concentrations of DBP(5.0 mg/L)seem to inhibit normal physiological activity in the vegetables,which resulted in a higher RCF and a lower TF and TSCF than in low-concentration treatment.The results will help to evaluate the safety of agricultural products and to provide evidence for screening DBP pollution-safe vegetable cultivars.

Biodegradation of Phthalate Esters by a Newly Isolated Acinetobacter sp. Strain LMB-5 and Characteristics of Its Esterase

Phthalate esters （PAEs） are extensively applied in industry, and they migrate to environment during the process of production, employ, and treatment and axe difficult to be degraded in nature. However, some microorganisms could use them as the carbon source to growth. In this study, an Acinetobacter sp. strain LMB-5, capable of utilizing PAEs, was isolated from a vegetable greenhouse soil. The degradation capability of strain LMB-5 was also investigated by incubation in mineral salt medium containing different PAEs, dimethyl phthalate （DMP）, diethyl phthalate （DEP）, di-n-butyl phthalate （DBP）, and di-（2-ethylhexyl） phthalate （DEHP）. The strain could grow well with DMP, DEP, DBP, and DEHP. When the concentration of DBP increased from 100 to 400 mg L-1, the half-life extended from 9.5 to 15.5 h. In the concentration range of DBP, the degradation ability of strain LMB-5 could be described by first-order kinetics. During the biodegradation of DBP, three intermediates, 1,2-benzenedicaxboxylic acid,butyl methyl ester, DMP, and phthalic acid （PA） were detected, and the proposed pathway of DBP was identified. By analysis of bioinformatics, one esterase was cloned from the genome of LMB-5 and expressed in Escherichia coll. It displayed an ability to break the ester bonds of DBP. The enzyme exhibited maximal activity at pH 7.0 and 40 ℃ with DBP as the substrate. It was activated by Cu2＋ and Fe3＋ and had a high activity in the presence of low concentrations of methanol or dimethylsulfoxide （each 10%, volume：volume）. The Acinetobacter sp. strain LMB-5 may make a contribution to the remediation of soils polluted by PAEs in the future.