Aqueous oxytetracycline degradation and the toxicity change of degradation compounds in photoirradiation process

The extensive use of antibiotics has been a worldwide environmental issue.In this study the fate of oxytetracycline (OTC),under photoirradiation,was investigated.The results showed that OTC photolysis followed first order model kinetics.Direct photolysis rate was found to be dependent on the initial OTC concentration,with k value ranging from 0.0075 to 0.0141 min^(-1),in the OTC concentration from 40 to 10 mg/L.OTC photolysis was highly pH-dependent and strongly enhanced at a high pH value,with a k value of...

Inuence of oxytetracycline on the structure and activity of microbial community in wheat rhizosphere soil

The microbial community composition in wheat rhizosphere was analyzed by detecting colony forming units （CFUs） in agar plates. The total CFUs in rhizosphere were 1.04×10^9/g soil with 9.0×10^8/g bacteria, 1.37×10^8/g actinomyces and 3.6×10^6/g fungi. The 10 dominant bacteria were isolated from wheat rhizosphere and were grouped into genus Bacillus according to their full length 16S rRNA gene sequences. Although belonging to the same genus, the isolated strains exhibited different sensitivities to oxytetracycline. When a series of the rhizosphere soil was exposed under various concentrations of oxytetracycline, the microbial community structure was highly affected with significant decline of CFUs of bacteria and actinomyces （22.2% and 31.7% at 10 mg/kg antibiotic, respectively）. This inhibition was clearly enhanced with the increase exposure dosage of antibiotic and could not be eliminated during 30 d incubation. There was no obvious influence of this treatment on fungi population. Among the four soil enzymes （alkaline phosphatase, acidic phosphatase, dehydrogenase and urease）, only alkaline phospbatase was sensitive to oxytetracycline exposure with 41.3% decline of the enzyme activity at 10 mg/kg antibiotic and further decrease of 64.3%-80.8% when the dosage over 30 mg/kg.

Degradation mechanisms of oxytetracycline in the environment

Over the past few decades,the usage of oxytetracycline(OTC),a kind of antibiotic,has increased with the development of aquaculture and livestock breeding.However,about 30–90%of the applied antibiotics are excreted as the parent compounds into the environment,especially with the application of animal manure to agricultural fields.This large influx of antibiotics may lead to the destruction of the natural microbial ecological community and pose great threats to human beings through the food chain.Therefore,the fate and toxicity of OTC in the environment are issues of great concern.Degradation of OTC,including the non-biodegradation and biodegradation,and the biological toxicity of its degradation products or metabolites,are reviewed in this paper.The non-biodegradation pathways include hydroxylation,quinonization,demethylation,decarbonylation,dehydration and secondary alcohol oxidation.Light(particularly UV light),pH and oxidizing substances play important roles in non-biodegradation.Biodegradation products include 4-epi-OTC(EOTC),2-acetyl-2-decarboxy-amido-OTC(ADOTC),α-apo-OTC andβ-apo-OTC.EOTC is an epimer and identied except for the configuration of the C4 dimethylamino group of OTC.Temperature and pH are the main factors affecting biodegradation pathways of OTC.In addition,this review discusses concerns over the biological toxicity of OTC degradation products.

Effects of Oxytetracycline on Methane Production and the Microbial Communities During Anaerobic Digestion of Cow Manure

The effects of different concentrations of oxytetracycline （OTC） on the dynamics of bacterial and archaeal communities during the mesophilic anaerobic digestion （37＆#176;C） of cow manure were investigated. Before anaerobic digestion, OTC was added to digesters at concentrations of 20, 50, and 80 mg L-1, respectively. Compared with no-antibiotic control, all methane productions underwent different levels of inhibition at different concentrations of OTC. Changes in the bacterial and archaeal communities were discussed by using PCR-denaturing gradient gel electrophoresis （DGGE）. Results showed that OTC affected the richness and diversity of bacterial and archaeal communities. The bacterial genus Flavobacterium and an uncultured bacterium （JN256083.1） were detected throughout the entire process of anaerobic digestion and seemed to be the functional bacteria. Methanobrevibacter boviskoreani and an uncultured archaeon （FJ230982.1） dominated the archaeal communities during anaerobic digestion. These microorganisms may have high resistance to OTC and may play vital roles in methane production.

Microbial community dynamics during composting of animal manures contaminated with arsenic,copper,and oxytetracycline

Effects of the heavy metal copper(Cu), the metalloid arsenic(As), and the antibiotic oxytetracycline(OTC) on bacterial community structure and diversity during cow and pig manure composting were investigated. Eight treatments were applied, four to each manure type, namely cow manure with:(1) no additives(control),(2) addition of heavy metal and metalloid,(3) addition of OTC and(4) addition of OTC with heavy metal and metalloid;and pig manure with:(5) no additives(control),(6) addition of heavy metal and metalloid,(7) addition of OTC and(8) addition of OTC with heavy metal and metalloid. After 35 days of composting, according to the alpha diversity indices, the combination treatment(OTC with heavy metal and metalloid) in pig manure was less harmful to microbial diversity than the control or heavy metal and metalloid treatments. In cow manure, the treatment with heavy metal and metalloid was the most harmful to the microbial community, followed by the combination and OTC treatments. The OTC and combination treatments had negative effects on the relative abundance of microbes in cow manure composts. The dominant phyla in both manure composts included Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. The microbial diversity relative abundance transformation was dependent on the composting time. Redundancy analysis(RDA) revealed that environmental parameters had the most influence on the bacterial communities. In conclusion, the composting process is the most sustainable technology for reducing heavy metal and metalloid impacts and antibiotic contamination in cow and pig manure. The physicochemical property variations in the manures had a significant effect on the microbial community during the composting process. This study provides an improved understanding of bacterial community composition and its changes during the composting process.

The impacts of oxytetracycline on humification during manure composting can be alleviated by adjusting initial moisture contents as illustrated by NMR

Oxytetracycline(OTC)residues have been found in soil and water,and they may pose potential risks to agricultural ecological environments.One of the most impactful ways for OTC to enter the soil and water environments is through excrement used as organic fertilizer.Therefore,it is important to remove OTC during manure composting and to understand the transformation of the organic materials during composting in the presence of OTC.In the present paper,chicken manure and wheat sawdust spiked with OTC were composted under different initial moisture contents(MC)to evaluate the degradation of OTC and changes of organic matter during the composting process.The MC has a significant effect on OTC degradation during composting.A higher MC of 65% was more conducive to OTC degradation(77.4%)and compost maturity compared to the lower MC.However,the higher MC of 65%could increase the ammonia volatilization by promoting nitrification compared to the lower MC.An increase in the initial MC could improve the composting temperature.NMR results illustrated that the presence of OTC could affect the internal transformation of aliphatics,and OTC inhibited compost humification.Thus,an initial MC of 55–65% can alleviate the impacts of OTC on humification during manure composting.

Chemiluminescence Determination of Tetracycline and Oxytetracycline in Pharmaceutical Preparations Using Ru(bipy)_3^(2+)-Cerium(Ⅳ) System

A new chemiluminescence (CL) method for the determination of tetracycline and oxytetracycline is developed, hased on the CL reaction of tetracycline and oxytetracycline with Ru(bipy)_3~2+ and Ce(IV). In sulfuric acid medium, the CL emission is generated upon continuous oxidation of Ru(bipy)_3~2+ by cerium (IV ). The emission intensity is greatly enhanced when tetracycline and oxytetracycline are introduced into the reaction system after acid degradation. Under the optimum conditions, the calibration curves are linear over the range of 8. 0 X 10^-8^-4. 0 X 10^-6 mol/L for tetracycline and of 2. 0 X 10^-7~4. 0 X 10^-5 mol/L for oxytetracycline, with the detection limits are 4. 2 X 10^-8 mol/L for tetracycline and 1. 5 X 10^-7 mol/L for oxytetracycline, respectively. The proposed method was used for the determination of tetracycline and oxytetracycline in pharmaceutical formulations with good results.

Strengthening decomposition of oxytetracycline in DBD plasma coupling with Fe-Mn oxide-loaded granular activated carbon

A catalytic approach using a synthesized iron and manganese oxide-supported granular activated carbon(Fe-Mn GAC) under a dielectric barrier discharge(DBD) plasma was investigated to enhance the degradation of oxytetracycline(OTC) in water. The prepared Fe-Mn GAC was characterized by x-ray diffraction and scanning electron microscopy, and the results showed that the bimetallic oxides had been successfully spread on the GAC surface. The experimental results showed that the DBD?+?Fe-Mn GAC exhibited better OTC removal efficiency than the sole DBD and DBD?+?virgin GAC systems. Increasing the fabricated catalyst and discharge voltage was favorable to the antibiotic elimination and energy yield in the hybrid process. The coupling process could be elucidated by the ozone decomposition after Fe-Mn GAC addition, and highly hydroxyl and superoxide radicals both play significant roles in the decontamination. The main intermediate products were identified by HPLC-MS to study the mechanism in the collaborative system.

Determination of Tetracycline and Oxytetracycline Residues in Honey by High Performance Liquid Chromatography

Honey is being used as a pure natural and as an ingredient in many foods, pharmaceuticals and cosmetics than ever before, so honey testing has become essential to maintain its healthful characteristics and protect public health. Tetracyclines （TCs） are used for the treatment or prevention of American and European foul broad in bee colonies which are caused especially by two species of bacteria--Paenibacillus larvae and Melissococcus pluton. The present study aimed to determine the tetracycline residues in different types of local and imported honey. The reversed-phase high performance liquid chromatography （HPLC） with ultraviolet detection （UV） was used. Tetracycline and oxytetracycline were extracted from honey with 0.01 M sodium succinate buffer. Of the examined samples, 31.25% and 12.50% had these oxytetracycline and tetracycline residues, respectively. It was observed that all the samples studied have been reported residues of tetracycline and oxytetracycline more than international standards of maximum residue limit （MRLs）.

Effect of Temperature and Metal Ions on Degradation of Oxytetracycline in Different Matrices

Composting is widely applied in animal manure treatment and reclamation. The degradation of organic pollutants during the composting treatment is attributed to two parallel processes: one is the bioprocess induced by the used microorganisms, and the other is the chemical process. In order to clarify the relative contribution of the chemical process to the compositing, in this paper, oxytetracycline (OTC) was chosen to study the degradation of tetracyclines (TCs) in water and chicken manure. It was observed that the degradation of OTC in water was much faster than that in chicken mature. At 40°C, 95% of OTC in water could be removed in two days, while it took about one month in mature. By increasing the temperature to 50°C, 60°C and 70°C, the required degradation time (with the degradation efficiency more than 95%) was shortened to 22, 13 and 9 days, respectively. This difference was caused by desorption hysteresis and irreversible fixation due to the formation of complexes of OTC with co-existed metal ions in the matrix. It was found that the coexisted Ca2+, Zn2+ and Ni2+ ions decreased the degradation of OTC, whereas Cu2+ ions promoted the degradation of OTC.

Oxytetracycline Uptake and Growth of Radish Plants (Raphanus sativus L.) in Animal Manureamended Soils

[Objective] Antibiotics are extensively given to livestock to promote its growth and reduce its diseases.Therefore,antibiotics may be present in manure and slurry from their parent compound and/or metabolites.The soil environments may be exposed to these antibiotics due to the application of animal manure to agricultural land.So,in this study,accumulation and phytotoxicity indicators were analyzed to evaluate the effects of oxytetracycline （OTC,C22H24N2O9HCI） on vegetable crop.[Method] A pot experiment was conducted in the greenhouse,radish plant （Raphanus sativus L.） was grown for seven weeks in two soils （sand soil and clayey soil） that were amended with pig manure and spiked with six levels （0,2,5,10,25 and 50 mg per kg of soil） of oxytetracycline for observing the potential effects of long-term application of antibiotics-contained animal manure on plant growth and determining whether or not radish plant grown in manure-applied soils absorbs OTC present in the soils.Contents of oxytetracycline in both root and shoot tissues were determined,and effects of soil oxytetracycline pollution on photosynthesis and biomass of the plant were monitored.[Result] The results showed that radish plant can absorb OTC from the soils.The concentration of OTC in plant tissues increased with increasing the concentration of OTC present in the soils,and was higher at the initial growth stage than at last stage of the plant.Higher concentration of OTC was found in roots than shoots of the plant.Bioavailability of OTC in the sandy soil was greater than that in clayey soil.OTC did not affect the growth of the plants when its concentration in the soils was less than 10 mg/kg.However,higher concentration of soil OTC （＞25 mg/kg） caused serious stress in the plant,reducing photosynthetic rate of leaves and biomass of both roots and shoot.[Conclusion] This study points out the potential human health risk associated with consumption of fresh vegetable grown in the soils amended with antibiotic laden manures.

Selective killing effect of oxytetracycline,propafenone and metamizole on A549 or Hela cells

Objective： To determine the selective killing effect of oxytetracycline, propafenone and metamizole on A549 or Hela cells. Methods： Proliferation assay, lactate dehydrogenase （LDH） assay, apoptosis detecting, flow cytometry and western blot were performed. Results： It was found that treatment with propafenone at the concentration of 0.014 g/L or higher for 48 h could induce apoptosis in Hela cells greatly, while it was not observed in oxytetracycline and metamizole at the concentration of 0.20 g/L for 48 h. Oxytetracycline, propafenone and metamizole all displayed evident inhibitory effects on the proliferation of A549 cells. The results of LDH assay demonstrated that the drugs at the test range of concentration did not cause necrosis in the cells. Propafenone could elevate the protein level of P53 effectively （P〈0.01）. Conclusions： Oxytetracycline, propafenone and metamizol （dipyrone） all displayed evident inhibitory effects on the proliferation of A549 cells. Propafenone also displayed evident inhibitory effects on the proliferation of Hela cells.

Lack of Gender Effect on the Pharmacokinetics of Oxytetracycline in Fenneropenaeus chinensis After Intramuscular Administration

Fenneropenaeus chinensis, an economically important shrimp species, currently suffers from epizootic diseases due to high density stocking and bacterial infections. Oxytetracycline （OTC） has been widely used to treat various systemic bacterial infec- tions in shrimp farming. In the present study, the effect of gender on pharmacokinetics of OTC in F. chinensis was investigated. The OTC concentrations in hemolymph of shrimp after single intramuscular administration （75 mg OTC per kg body weight） were ana- lyzed by high performance liquid chromatography and best described with a two-compartment open model which is characterized by a short elimination half-life, low clearance, and a relatively large apparent volume of distribution. The pharmacokinetic equations were Ct= 58.54e-0.38t＋ 11.67e-0.04t for females; and Ct= 27.94e-0.28t＋ 14.87e-0.04t for males. The distribution and elimination half-lives of OTC were 1.82 and 19.58 h, respectively, in females and 2.50 and 16.11 h, respectively, in males at 22 ℃. The areas under the drug concentration curve were 480 mg L-1 h-1 in females and 430 mg L-1 h-1 in males. The total body clearance of the drug was 157.11 mL kg-1 h-l in females and 172.47mLkg-1 h-1 in males. The apparent volume distribution was 4.44 in females and 4.01 Lkg-1 in males. There was no significant difference in pharmacokinetic parameters between female and male shrimps, indicating that there is no need to consider the gender effect in clinical use of OTC in F. chinensis farming.

DETERMINATION OF TETRACYCLINE AND OXYTETRACYCLINE BY FLOW-INJECTION CHEMILUMINESCENCE METHOD

Objective To establish a rapid and precise continuous flow-injection chemiluminescence method for the determination of tetracycline and oxytetracycline. Methods In NaOH solution, tetracycline and oxytetracycline can sensitize obviously the chemiluminesence (CL) intensity of the reaction of luminol with KIO_4, the sensitized CL intensity is proportional to the concentration of tetracycline and oxytetracycline. So, a new flow-injection CL method has been developed. The optimum chemical conditions for the CL reaction were investigated. Results Under the optimized conditions (KIO_ 4 concentration: 1.0×10 -5 mol/L; NaOH concentration: 0.1 mol/L; luminol concentration: 1.0×10 -4mol/L), tetracycline and oxytetracycline were determined. The linear range of the working curves was 1.0×10 -7 - 1.0×10 -4g/mL, the detection limits was 1.0×10 -8g/mL and 1.1×10 -8g/mL, and the relative standard deviation was 2.6% (C_S=1.0×10 -6g/mL; n=11) and 2.0% (C_S=1.0×10 -6g/mL; n=11) respectively. Conclusion The method is simple, rapid, and sensitive, and it has been successfully applied to the the determination of tetracycline and oxytetracycline tablets, the mean recoveries being 99.7% and 98.8% respectively.

Yeast-TiO₂Biotemplate for Oxytetracycline Solar Photodecomposition

The detection of the pharmaceutical compounds used in human and veterinary medicine is in several environmental matrices (surface waters, effluents, groundwater, soils, and sediments), and such presence promotes the resistance bacteria development, making them ineffective in some diseases treatment. The research project promotes the TiO2 synthesis using yeast culture as biotemplate, the step followed by the microstructure characterization with surface area enhancement;such properties are responsible for the improvement of solar photodecomposition processes of the veterinary antibiotic oxytetracycline. In such simple and standard process conditions the system reaches about 84% of removal percentage with a better agreement with the pseudo-first-order with the Pearson coefficient in the range from 0.82 to 0.94 and K1 = 0.035 M−1∙s−1. The degradation rate constant increased with the increasing initial Yeast-TiO2 dosage until the maximum mass of 0.1 g or with the decreasing of initial oxytetracycline concentration. The solar light used as a sustainable irradiation source is abundant and low cost in tropical countries, perfect to be applied in water treatment to decompose the pharmaceuticals pollutants, as the veterinarian antibiotics. The study demonstrates that solar photodecomposition is an efficient treatment technology for the removal of antibiotics from polluted water and provides insightful information on the potential practical application of this technology to treat contaminated water, possibly also in rural, distant areas.

Oxytetracycline Water Contamination Treated with Biocarbon TiO2 and Solar Photodecomposition

Reliable data of antibiotic use and environmental discharge as veterinary medicine are essential to help countries raise awareness of the appropriate use, control, and correct water release. The first approach is to change the regulatory framework based on consuming information, use policy, and discharge laws. The important research contribution is a novel water treatment process to treat, remove, and reduce antibiotic concentration in discharged water, mainly those used in the animal protein industry. The low particle biochar added during the titanium isopropoxide hydrolysis reduces the titanium dioxide (TiO2) agglomerates and promotes the adsorption surface process. Such improved catalyst material enhances the solar decomposition efficiency to 93% from original oxytetracycline with better correspondence with the Elovich kinetics, intraparticle diffusion, R-P isotherm, and Langmuir-Hinshelwood model.

Simple and Selective Colorimetric Detection of Oxytetracycline Based on Fe(III) Ion-3,3’,5,5’-Tetramethylbenzidine

Oxytetracycline (OTC) is a common antibacterial agent used for the control of animal diseases. OTC abuse can seriously affect human health. Herein, based on the Fe(III)-3,3’,5,5’-tetramethylbenzidine (Fe(III)-TMB) system, a facile and rapid colorimetricassay for oxytetracycline (OTC) was successfully developed. The addition of OTC could remarkably enhance the Fe(III)-oxidized TMB reaction and the absorbance increase of Fe(III)-TMB solution is proportional to the added OTC. The linear range of proposed sensor for OTC was from 20 nM to 1000 nM with the detection limit of 7.97 nM. The high sensitivity for OTC detection was successfully achieved under optimal conditions. For real sample analysis, recoveries of 89.93% to 100.02% was obtained. This is the first report for detecting OTC based on the nonenzymatic colorimetric reaction using the intrinsic oxidized activity of OTC/Fe3+ complex. The present simple, low-cost and visualized sensor has great potential for OTC detection in food.

A facile strategy to construct MOF-based nanocatalyst with enhanced activity and selectivity in oxytetracycline degradation

Recently,many efforts have been dedicated to construct artificial catalysts with enzyme-like activity.However,it is still a big challenge to endow artificial catalysts with specific substrate selectivity.In this study,we developed a facile strategy to construct a MIL-53(Fe)-based nanocatalyst with designable selectivity in the degradation of oxytetracycline(OTC).Through the Fe–O–P conjunction,oxytetracycline aptamer(OA)can be easily anchored on MIL-53(Fe)to provide the specific site for OTC binding.We verified that the obtained MIL-53(Fe)-Apt nanocatalyst displayed enhanced catalytic ability in the degradation of OTC,whereas obvious suppression toward other substrate analogues.This performance therefore brings about an anticipated selectivity toward OTC.Moreover,we highlighted that the configuration of aptamers on MIL-53(Fe)can be modulated through varying conjunction mode.Structure–function analysis revealed that aptamer configuration affects the local concentration of substrate around catalytic site,which thus decides the catalytic performance toward OTC.This work presented a facile and promising strategy for developing artificial catalysts with designable selectivity.

Improvement of oxytetracycline production mediated via cooperation of resistance genes in Streptomyces rimosus

Increasing the self-resistance levels of Streptomyces is an effective strategy to improve the production of antibiotics.To increase the oxytetracycline(OTC) production in Streptomyces rimosus,we investigated the cooperative effect of three co-overexpressing OTC resistance genes:one gene encodes a ribosomal protection protein(otrA) and the other two express efflux proteins(otrB and otrC).Results indicated that combinational overexpression of otrA,otrB,and otrC(MKABC) exerted a synergetic effect.OTC production increased by 179%in the recombinant strain compared with that of the wild-type strain M4018.The resistance level to OTC was increased by approximately two-fold relative to the parental strain,thereby indicating that applying the cooperative effect of self-resistance genes is useful to improve OTC production.Furthermore,the previously identified cluster-situated activator OtcR was overexpressed in MKABC in constructing the recombinant strain MKRABC;such strain can produce OTC of approximately7.49 g L^((-1)),which represents an increase of 19%in comparison with that of the OtcR-overexpressing strain alone.Our work showed that the cooperative overexpression of self-resistance genes is a promising strategy to enhance the antibiotics production in Streptomyces.

Performance of bimetallic nanoscale zero-valent iron particles for removal of oxytetracycline

In this study, bimetallic nanoscale zero-valent iron particles（nZVI）, including copper/nanoscale zero-valent iron particles（Cu/nZVI） and nickel/nanoscale zero-valent iron particles（Ni/nZVI）, were synthesized by one-step liquid-phase reduction and applied for oxytetracycline（OTC） removal. The effects of contact time and initial p H on the removal efficiency were studied. The as-prepared nanoscale particles were characterized by scanning electron microscopy（SEM）, energy dispersive spectroscopy（EDS） and X-ray diffraction（XRD）. Finally, the degradation mechanisms of OTC utilizing the as-prepared nanoparticles were investigated by using X-ray photoelectron spectroscopy（XPS） and mass spectrometry（MS）. Cu/n ZVI presented remarkable ability for OTC degradation and removed71.44% of OTC（100 mg/L） in 4 hr, while only 62.34% and 31.05% of OTC was degraded by Ni/nZVI and nZVI respectively. XPS and MS analysis suggested that OTC was broken down to form small molecules by ·OH radicals generated from the corrosion of Fe0. Cu/nZVI and Ni/n ZVI have been proved to have potential as materials for application in OTC removal because of their significant degradation ability toward OTC.