[en] Biopurification systems (BPS) are employed for the treatment of pesticide-containing wastewaters. In this work, a biomixture (active core of BPS) complemented by the addition of the fungus Trametes versicolor was evaluated for the elimination of a mixture of pesticides under different treatment conditions. The biomixture achieved high removal of all the pesticides assayed after 16 d: atrazine (68.4%, t_1/2: 9.6 d), carbendazim (96.7%, t_1/2: 3.6 d), carbofuran (98.7%, t_1/2: 3.1 d) and metalaxyl (96.7%, t_1/2: 3.8 d). Variations in the treatment conditions including addition of the antibiotic oxytetracycline and co-bioaugmentation with a bacterial consortium did not significantly affect the removal performance of the biomixture. Bacterial and fungal community profiles determined by DGGE analyses revealed changes that responded to biomixture aging, and not to antibiotic or pesticide addition. The proposed biomixture exhibits very efficient elimination during simultaneous pesticide application; moreover, the matrix is highly stable during stressful conditions such as the co-application of antibiotics of agricultural use.

[en] Phycoremediation of swine wastewater is an attractive treatment to remove contaminants and simultaneously produce valuable feedstock biomass. However, there is a lack of information about the application of phycoremediation on veterinary antibiotic removal. Thus, this research investigated the degradation of tetracycline, oxytetracycline, chlortetracycline and doxycycline in swine wastewater treated with phycoremediation. The tetracyclines degradation kinetics was adjusted to the pseudo-first-order kinetics model, with kinetic constant k₁ in the following: 0.36 > 0.27>0.19 > 0.18 (d⁻¹) for tetracycline, doxycycline, oxytetracycline and chlortetracycline, respectively. The maximum concentration of microalgae biomass (342.4 ± 20.3 mg L⁻¹) was obtained after 11 days of cultivation, when tetracycline was completely removed. Chlortetracycline concentration decreased, generating iso-chlortetracycline and 4-epi-iso-chlortetracycline. Microalgae biomass harvested after antibiotics removal presented a carbohydrate-rich content of 52.7 ± 8.1, 50.1 ± 3.3, 51.4 ± 5.4 and 57.4 ± 10.4 (%) when cultured with tetracycline, oxytetracycline, chlortetracycline and doxycycline, respectively, while the control culture without antibiotics presented a carbohydrate content of 40 ± 6.5%. These results indicate that could be a valuable source for bioenergy conversion.

[en] Tetracycline antibiotics including tetracycline (TTC), oxytetracycline (OTC) and chlorotetracycline (CTC) undergo rapid transformation to yield various products in the presence of MnO₂ at mild conditions (pH 4-9 and 22 ^oC). Reaction rates follow the trend of CTC > TTC > OTC, and are affected by pH and complexation of TCs with Mg²⁺ or Ca²⁺. Experimental results of TTC indicate that MnO₂ promotes isomerization at the C ring to form iso-TTC and oxidizes the phenolic-diketone and tricarbonylamide groups, leading to insertion of up to 2 O most likely at the C9 and C2 positions. In contrast, reactions of OTC with MnO₂ generate little iso-OTC, but occur mainly at the A ring's dimethylamine group to yield N-demethylated products. CTC yields the most complicated products upon reactions with MnO₂, encompassing transformation patterns observed with both TTC and OTC. The identified product structures suggest lower antibacterial activity than that of the parent tetracyclines. - Highlights: → Tetracyclines transform rapidly by MnO₂ to yield complicated products. → Isomerized, (hydr)oxygenated and N-demethylated products are formed. → Transformation product structures may suggest lowered antibacterial activity. - The complex transformation pathways of three popular tetracycline antibiotics (tetracycline, oxytetracycline and chlorotetracycline) with MnO₂ under environmental conditions are systematically evaluated and elucidated.

[en] Highlights: • Nanofibers delivered OTC and ZnO, antibacterial agents against periodontal disease. • PCL nanofibers exhibited a sustained OTC release for up to 5 days. • Nanofibers were not cytotoxic on fibroblastic cells. • Nanofibers exhibited good antimicrobial activity against mixed bacterial culture. -- Abstract: Periodontal diseases (PD) are mixed bacterial infections caused by microorganisms that colonize the tooth surface, leading to destructions at tooth-supporting tissues. Several local delivery systems, as nanofibers, have been developed for the treatment of PD. The purpose of the present study was developing polycaprolactone (PCL) nanofibers incorporating two antibacterial agents, OTC and ZnO, for use in the treatment of PD. Nanofibers were produced by electrospinning method: PCL loaded with ZnO (PCL-Z), PCL loaded with OTC (PCL-OTC), PCL loaded with OTC and ZnO (PCL-OTCz) and pristine PCL (PCL-P). The nanofibers were characterized physicochemically using different techniques. In addition, in vitro study of the OTC release from the nanofibers was performed. The PCL-OCT showed sustained release of the drug up to 10 h, releasing 100% of OTC. However, the PCL-OTCz nanofiber showed a slow release of OTC up to 120 h (5th day) with 54% of drug retention. The cytotoxicity assay showed that PCL-OTC nanofiber was slightly cytotoxic after 48 h and the other nanofibers were non-cytotoxic. The antibacterial activity of the nanofibers was evaluated by qualitative and quantitative analysis and against mixed bacterial culture, composed of four Gram-negative anaerobic bacteria involved in periodontal diseases. The disk diffusion method showed that the PCL-OTC displayed higher inhibition zone than PCL-OTCz (p < 0.001). The quantitative analysis, evaluated by broth culture, showed that the PCL-OTC and PCL-OTCz exhibited excellent activity against a mixed bacterial culture with growth inhibition of 98.0% and 97.5%, respectively. Based on these results, the PCL-OTCz nanofibers developed have great potential as a drug delivery system for the PD treatment.

[en] Highlights: • A ferriporphyrin-based porous organic framework was prepared successfully. • The aptasensor can detect ultra-trace oxytetracycline even in real samples. • The biosensor exhibits outstanding selectivity, high stability and available reproducibility. A ferriporphyrin-based porous organic framework (Fe-PPOF) was successfully synthesized via the Sonogashira coupling reaction. By reason of high surface area, extended π-conjugation skeleton and excellent stability, Fe-PPOF can efficiently immobilize aptamers to fabricate an electrochemical aptasensor for detecting ultra-trace oxytetracycline (OTC) with the low limitation of detection of 2.05 fg·mL⁻¹. Meanwhile, this biosensor exhibits high selectivity, good stability and available reproducibility. More importantly, the Fe-PPOF-based electrochemical aptasensor can quantitatively detect OTC in real samples.

[en] The purpose of the study was an evaluation of the effect of ionizing radiation on detection of oxytetracycline residues in poultry meat. Oxytetracycline was chosen as a representative of tetracyclines which are often applied in poultry for therapeutical reasons. The experiment was conducted using both broiler meat treated by oxytetracycline and slurry of broiler meat containing appropriate concentration of this antibiotic. A traditional microbiological method for determination of antibiotics antimicrobial activity was used. A significant decrease of oxytetracycline concentration in meat slurry as a result of irradiation was noted. A dose of 1 kGy reduced concentration of tetracycline to ca 40% and a dose of 3 kGy reduced it to ca 3%. In ground poultry meat a dose of 1 kGy reduced this antibiotic concentration to 70%, a dose of 3 kGy reduced oxytetracycline concentration to 35% and a 5 kGy dose reduced it up to ca 18% of initial concentration. It can be concluded that irradiation of poultry meat with radurization doses can cause some difficulties in detection of tetracycline residues in meat using traditional microbiological methods of detection. (author)

[en] The impact of a mixture of oxytetracycline, chlortetracycline, tetracycline and doxycycline on Myriophyllum sibiricum and Lemna gibba was investigated using fifteen 12,000-L microcosms (k = 5, n = 3). Significant concentration-response relationships were only found for M. sibiricum, where dry mass was 69, 47, 30, and 7% of controls at respective treatment concentrations of 0.080, 0.218, 0.668, and 2.289 μmol/L. Somatic endpoints were strongly and negatively correlated with percent light transmission, except plant length, which was positively correlated. Treated microcosms experienced a reduction in the percent of surface irradiance penetrating the water column as high as 99.8% at a depth of 70 cm, relative to controls. Position relative to the water column was likely responsible for the differential effects observed between floating (L. gibba) and submerged (M. sibiricum) species of macrophytes. A hazard quotient assessment of the lowest EC₁₀ value indicated significant risk, exceeding the critical HQ value, but not the lowest EC₂₅ value. - Mixtures of tetracycline antibiotics pose a risk to submerged but not floating aquatic plants

No abstract available

[en] This study was aimed to evaluate the effect of chitosan nanoparticles loaded oxytetracycline hydrochloride on health status, and survival rate of common carp infected with Columnaris disease. A total 160 fish of Cyprinuscarpio L. weighed between 48-50g were randomly distributed into eight treatments, and 48 fish were used to determine LD50. (Two replications for each treatment). The bacterial concentration of F. column are that used for infection test after a serial dilution was 0.2ml (1.8 × 106 CFU/ml), then removal a few of scales near the caudal fin and injection subcutaneously. The trial injected fish treated by ordinary oxytetracycline hydrochloride as T0 in dose 20 mg/L and T1, T2, T3, T4 and T5 treated by chitosan nanoparticles loaded oxytetracycline hydrochloride in dose 20, 15, 10, 5, 2.5 mg/L respectively. The control (+) infected without gave treatment, whilst, control-was no infected. All the treatments gave the bath treatment 1-hour per-day for 7 days, clinical signs post treatment were evaluated also, RBC counts, WBC counts, PCV, Hb, Total proteins, Albumin, Globulin, A/G ratio and survival rate were measured. One week after the end of the treatment period, an improvement in health and feed consumption was observed in T4 and T3. The results revealed significant increases (P < 0.05) in PCV, Hb, RBCs count and WBCcount of C. carpio post-treatment in treated groups T4 (26.46%, 8.95 g/dl and 2.27 cell×106/mm3 and22.10 cell×103/mm3respectively) compared with control (+) (15.95%, 5.94 g/dl,1.55 cell×106/mm3 and19.13 cell×103/mm3respectively). In addition, Total proteins, Albumin, Globulin showed significant increase (P < 0.05) in T2, T3, T4, T5 comparison with the control+ group and highest values were recorded in T4. While, The result of A/G ratio revealed a significantly decreased (P 0.05) in all treatments in compared with Control(-) and no significant difference (P 0.05) compared with Control(+). The best A/G ratio recorded in T4 and T5. In addition, survival rate 90% recorded as the highest value in T4. This current administration technique of oxytetracycline, proved to become much more efficient with respect to conventional exposure and has the potential to minimize the usage of antibiotics in fish farms and regarding environmental effects. (paper)

[en] Highlights: • The novel (10, 10) arm-chair blue phosphorene nanotube (blue-PNT) possesses band gap of 2.639 eV. • The blue-PNT is used to adsorb oxytetracycline (OC) and sulfapyridine (SP) from the water. • The charge transfer is noticed upon adsorption of oxytetracycline and sulfapyridine on blue-PNT. • The findings reveal that blue-PNT can be used to remove oxytetracycline and sulfapyridine molecules from water. The efficiency of (10,10) arm-chair based blue phosphorene nanotube (blue-PNT) to identify and remove the two popular toxic antibiotics – oxytetracycline (OC) and sulfapyridine (SP) from the water bodies are inspected by incorporating the DFT method. The geometrical firmness of the fundamental blue-PNT is verified from the cohesive energy of −4.417 eV/atom. Further, the electronic properties of the fundamental and antibiotics-adsorbed blue-PNT are investigated and the desirable electron-level modifications of the blue-PNT upon the target antibiotics interaction at three distinguished positions are observed. Besides, the estimated surface assimilation properties of the antibiotics-interacted blue-PNT like the prominent Bader charge transfer, significant adsorption energy, and average band gap variations proclaims the supreme efficiency of blue-PNT to act as a novel base to remove the harmful antibiotics – oxytetracycline and sulfapyridine from the water bodies.