High Concentrations Of Tetracycline Research Articles

Development of transcriptional factor-based whole-cell biosensors to monitor and degrade antibiotics using mutant cells obtained via adaptive laboratory evolution

With the widespread use of antibiotics and increasing environmental concerns regarding antibiotic abuse, the detection and degradation of antibiotic residues in various samples has become a pressing issue. Transcriptional factor (TF)-based whole-cell biosensors are low-cost, easy-to-use, and flexible tools for detecting chemicals and controlling bioprocesses. However, because of cytotoxicity caused by antibiotics, the application of such biosensors is limited in the presence of antibiotics. In this study, we used antibiotic-tolerant mutants obtained via adaptive laboratory evolution (ALE) to develop TF-based whole-cell biosensors for antibiotic monitoring and degradation. The biosensors had high performance and stability in detecting relatively high concentrations of tetracycline (Tc) and nisin. The ALE mutant-based Tc biosensor exhibited a 10-fold larger linear detection range than the wild-type strain-based biosensor. Then, the Tc biosensor was employed to detect residual amounts of Tc in mouse stool, serum, and urine samples and facilitate Tc biodegradation in mouse stool, demonstrating its high utility. Considering that ALE has been demonstrated to enhance cell tolerance to various toxic chemicals, our strategy might facilitate the development of whole-cell biosensors for most antibiotics and other toxic ligands.

Activating peroxymonosulfate with Fe-doped biochar for efficient removal of tetracycline: Dual action of reactive oxygen species and electron transfer

If pharmaceutical wastewater is not managed effectively, the presence of residual antibiotics will result in significant environmental contamination. In addition, inadequate utilization of agricultural waste represents a squandering of resources. The objective of this research was to assess the efficacy of iron-doped biochar (Fe-BC) derived from peanut shells in degrading high concentrations of Tetracycline (TC) wastewater through activated peroxymonosulfate. Fe-BC demonstrated significant efficacy, achieving a removal efficiency of 87.5% for TC within 60 min without the need to adjust the initial pH (20 mg/L TC, 2 mM PMS, 0.5 g/L catalyst). The degradation mechanism of TC in this system involved a dual action, namely Reactive Oxygen Species (ROS) and electron transfer. The primary active sites were the Fe species, which facilitated the generation of SO4•-, •OH, O2•-, and 1O2. The presence of Fe species and the C=C structure in the Fe-BC catalyst support the electron transfer. Degradation pathways were elucidated through the identification of intermediate products and calculation of the Fukui index. The Toxicity Estimator Software Tool (T.E.S.T.) suggested that the intermediates exhibited lower levels of toxicity. Furthermore, the system exhibited exceptional capabilities in real water and circulation experiments, offering significant economic advantages. This investigation provides an efficient strategy for resource recycling and the treatment of high-concentration antibiotic wastewater.

Effects of antibiotics on secondary metabolism and oxidative stress in oilseed rape seeds.

Cruciferae brassica oilseed rape is the third largest oilseed crop in the world and the first in China, as well as a fertilizer-dependent crop. With the increased application of organic fertilizers from livestock manure in agricultural production in recent years, the resulting antibiotic pollution and its ecological health effects have attracted widespread attention. In this study, typical tetracycline and sulfonamide antibiotics tetracycline (TC) and sulfamethoxazole (SMZ) were used to investigate the effects of antibiotics on rapeseed quality and oxidative stress at the level of secondary metabolism on the basis of examining the effects of the two drugs on the growth of soil-cultivated rapeseed seedlings. The results showed that both plant height and biomass of rapeseed seedlings were significantly suppressed and ROS were significantly induced in rapeseed by exposure to high concentrations (2.5mg/kg) of TC and SMZ. Carotenoids, tocopherols, and SOD enzymes were involved in the oxidative stress response to scavenge free radicals in rapeseed, but phenolic acids and flavonoids contents were decreased, which reduced the quality of the seeds to some extent.

Three-dimensional porous La(OH)3/g-C3N4 adsorption-photocatalytic synergistic removal of tetracycline.

La(OH)3/g-C3N4 composites were successfully synthesized via one-step calcination using urea, melamine, and La(NO3)3·nH2O as raw materials, and applied to UV-induced photocatalytic tetracycline (TC) removal. Comprehensive characterization by an X-ray diffraction (XRD), Fourier transform infrared reflection (FT-IR), high-resolution transmission electron microscope (HRTEM), and other techniques analyzed effects of La3+ doping, especially N vacancies and cyano groups as active sites. Compared to pure g-C3N4 and La(OH)3, synthesized La(OH)3/g-C3N4 composites exhibited a three-dimensional porous nanosheet structure with specific surface area of 83.62 m2/g and equilibrium TC adsorption capacity up to 285.59 mg/g; La(OH)3 doping significantly improved composite structure. After dispersing 10 mg La-CN-0.5 photocatalyst in 60 mL 40 mg/L TC solution, TC removal reached 91.08% in 30 min under UV irradiation, exhibiting excellent performance. Additionally, La-CN-0.5 showed significant adsorption-photocatalytic synergism, with the quasi-primary kinetic constant increased by 1.83-fold. The efficiency of high tetracycline (TC) concentration treatment through adsorption photocatalytic degradation by La-CN-0.5 was confirmed by the utilization of free radical trapping and electron spin resonance (ESR) tests. The significant involvement of ∙O2-, ∙OH, and h+ in this process was observed. These findings propose that the prepared La-CN-0.5 material exhibits a unique capability for adsorption photocatalysis, providing a promising approach for the efficient removal of high TC concentrations.

Undaria pinnatifida (wakame)-derived Fe, N co-doped graphene-like hierarchical porous carbon as highly efficient catalyst for activation of peroxymonosulfate (PMS) toward degradation of tetracycline (TC)

The use of biomass as a catalyst offers a cost-effective and efficient approach for various processes, including the activation of peroxymonosulfate (PMS) to degrade contaminants. In this study, we successfully obtained Fe and N co-doped graphene-like hierarchical porous structure carbon (Fe-N/BC) by using undaria pinnatifida (wakame) as the precursor. The Fe-N/BC catalyst was utilized to activate PMS and degrade tetracycline (TC). Characterization results demonstrated an even distribution of Fe and N on the surface of the porous structure carbon. Compared to BC@PMS and N/BC@PMS, the Fe-N/BC@PMS system exhibited excellent degradation performance, achieving an 83.9 % degradation of TC in just 5 min with an ultralow catalyst dosage (Ca = 0.05 g/L) and a high TC concentration (TC = 0.03 g/L). Furthermore, experiments on radicals quenching and electron paramagnetic resonance (EPR) analysis indicated that singlet oxygen (1O2), a non-radical species, was demonstrated as the primary reactive oxygen species (ROS). The degradation mechanical analysis suggested that zero-valent iron (Fe0), pyridinic N, graphitic N, and Fe-Nx in the Fe-N/BC were the reason for the high catalytic activity. Moreover, the degradation pathways of TC were suggested through the use of LC-MS. Additionally, the ECOSAR system was employed to assess the toxicity of the intermediate products. This study reveals the active site and its mechanism in Fe-N composite biocarbon catalysts, providing a new method for synthesizing algal biocarbon catalysts.

Corynebacterium oculi-related bacterium may act as a pathogen and carrier of antimicrobial resistance genes in dogs: a case report

BackgroundThe genus Corynebacterium comprises well-known animal and human pathogens as well as commensals of skin and mucous membranes. Species formerly regarded as contaminants are increasingly being recognized as opportunistic pathogens. Corynebacterium oculi has recently been described as a human ocular pathogen but has so far not been reported in dogs.Case presentationHere we present two cases of infection with a novel Corynebacterium sp., a corneal ulcer and a case of bacteriuria. The two bacterial isolates could not be identified by MALDI-TOF MS. While 16 S rRNA gene (99.3% similarity) and rpoB (96.6% identity) sequencing led to the preliminary identification of the isolates as Corynebacterium (C.) oculi, whole genome sequencing revealed the strains to be closely related to, but in a separate cluster from C. oculi. Antimicrobial susceptibility testing showed high minimal inhibitory concentrations of lincosamides, macrolides, tetracycline, and fluoroquinolones for one of the isolates, which also contained an erm(X) and tet-carrying plasmid as well as a nonsynonymous mutation leading to an S84I substitution in the quinolone resistance determining region of GyrA.ConclusionsWhile the clinical signs of both dogs were alleviated by antimicrobial treatment, the clinical significance of these isolates remains to be proven. However, considering its close relation with C. oculi, a known pathogen in humans, pathogenic potential of this species is not unlikely. Furthermore, these bacteria may act as reservoir for antimicrobial resistance genes also in a One Health context since one strain carried a multidrug resistance plasmid related to pNG3 of C. diphtheriae.

Titanium metal–organic framework-derived nanocrystalline TiO2-supported nitrogen-doped carbon nanostructures as highly efficient antibiotic adsorbents

Metal-organic frameworks (MOFs) are explored extensively as a distinctive precursor for producing porous metal oxide-supported nitrogen-doped carbon nanomaterials. MOF-derived materials can offer tailored porosity, structure, and elemental composition so they are gaining prominence as a new-generation adsorbent for emerging antibiotic contaminant removal in aqueous solutions. In this study, we demonstrate the fabrication of nanocrystalline titanium dioxide-supported nitrogen-doped carbon nanostructures (TiO2@NC) obtained from a titanium metal–organic framework (NH2-MIL-125(Ti)) as a starting precursor. When applied as an adsorbent, TiO2@NC nanospheres efficiently removed high concentrations of tetracycline (TC) in aqueous solutions. The TiO2@NC adsorption process obeyed the Langmuir model and pseudo-second-order kinetics. The optimum adsorption capacity of the TiO2@NC nanospheres is estimated to be 1187.08 mg g−1, which is remarkably superior to several previously reported adsorbents for TC removal. The TiO2@NC adsorbent performs efficiently in a broad pH range (3–8) and shows excellent stability. The post-adsorption characterization signifies the crucial role of the adsorbent's nitrogen sites, surface area, and porous sphere morphology in achieving efficient TC removal through hydrogen bonding, π-π interactions, and surface complexation.

Biochar-layered double hydroxide composites for the adsorption of tetracycline from water: synthesis, process modeling, and mechanism.

Antibiotic-contaminated water is a crucial issue worldwide. Thus, in this study, the MgFeCa-layered double hydroxides were supported in date palm-derived biochar (B) using co-precipitation, hydrothermal, and co-pyrolysis methods. It closes gaps in composite design for pharmaceutical pollutant removal, advances eco-friendly adsorbents, and advances targeted water cleanup by investigating synthesis methodologies and gaining new insights into adsorption. The prepared B-MgFeCa composites were investigated for tetracycline (TC) adsorption from an aqueous solution. The B-MgFeCa composites synthesized through co-precipitation and hydrothermal methods exhibited better crystallinity, functional groups, and well-developed LDH structure within the biochar matrix. However, the co-pyrolysis method resulted in the LDH structure breakage, leading to the low crystalline composite material. The maximum adsorption of TC onto all B-MgFeCa was obtained at an acidic pH range (4-5). The B-MgFeCa composites produced via hydrothermal and co-pyrolysis methods showed higher and faster TC adsorption than the co-precipitation method. The kinetic results can be better described by Langmuir kinetic and mixed order models at low and high TC concentrations, indicating that the rate-limiting step is mainly associated with active binding sites adsorption. The Sip and Freundlich models showed better fitting with the equilibrium data. The TC removal by B-MgFeCa composites prepared via hydrothermal, the highest estimated uptake which is around 639.76 mg.g-1 according to the Sips model at ambient conditions, and co-pyrolysis was mainly dominated by physical and chemical interactions. The composite obtained via the co-precipitation method adsorbed TC through chemical bonding between surface functional groups with anionic species of TC molecule. The B-MgFeCa composite showed excellent reusability performance for up to five cycles with only a 30% decrease in TC removal efficiency. The results demonstrated that B-MgFeCa composites could be used as promising adsorbent materials for effective wastewater treatment.

Efficient degradation of tetracycline in a photo-Fenton system constructed by combining MOF-derived Fe2O3/C/In2O3 heterojunction with vitamin C

The MOF-derived Fe2O3/C/In2O3 heterogeneous materials combined with vitamin C (AA) were first designed to construct a photo-Fenton system for the decomposition of tetracycline (TC). In this work, comparative analysis of TC degradation efficiency, photoluminescence (PL), ultraviolet-visible diffuse reflectance spectroscopy (UV–vis DRS), and transient photocurrent (I-T) performance analysis revealed that the heterojunctions not only effectively promoted the response of visible light by the catalytic system, but also facilitated the separation of photogenerated electrons and holes to increase electron density, thus, the conversion efficiency of Fe3+/Fe2+ was effectively improved, and hydrogen peroxide was activated to generate ･OH. Besides, the conversion efficiency of Fe3+/Fe2+ has been further improved due to the addition of AA, which provides many active electrons for heterogeneous materials. The capture experiments revealed that the active substances (･OH, h+, and ･O-2) played a main role in the degradation of TC. The system degraded high concentrations of TC with the efficiency of 88.9 % within 60 min. The strategy provided a new method for improving the photo-Fenton advanced oxidation performance of Fe2O3.

Comparative Metagenomic and Metatranscriptomic Analyses Reveal the Response of Black Soldier Fly (Hermetia illucens) Larvae Intestinal Microbes and Reduction Mechanisms to High Concentrations of Tetracycline.

Black soldier fly (Hermetia illucens L) larvae (BSFL) possess remarkable antibiotic degradation abilities due to their robust intestinal microbiota. However, the response mechanism of BSFL intestinal microbes to the high concentration of antibiotic stress remains unclear. In this study, we investigated the shift in BSFL gut microbiome and the functional genes that respond to 1250 mg/kg of tetracycline via metagenomic and metatranscriptomic analysis, respectively. The bio-physiological phenotypes showed that the survival rate of BSFL was not affected by tetracycline, while the biomass and substrate consumption of BSFL was slightly reduced. Natural BSFL achieved a 20% higher tetracycline degradation rate than the germ-free BSFL after 8 days of rearing. Metagenomic and metatranscriptomic sequencing results revealed the differences between the entire and active microbiome. Metatranscriptomic analysis indicated that Enterococcus, Vagococcus, Providencia, and Paenalcaligenes were the active genera that responded to tetracycline. Furthermore, based on the active functional genes that responded to tetracycline pressure, the response mechanisms of BSFL intestinal microbes were speculated as follows: the Tet family that mediates the expression of efflux pumps expel tetracycline out of the microbes, while tetM and tetW release it from the ribosome. Eventually, tetracycline was degraded by deacetylases and novel enzymes. Overall, this study provides novel insights about the active intestinal microbes and their functional genes in insects responding to the high concentration of antibiotics.

Novel synthesis of siligraphene/tungstates (g-SiC/AWO) with promoted transportation of photogenerated charge carriers via direct Z-scheme heterojunctions

We developed here the efficient photocatalysts for the removal of high concentrations of tetracycline under visible light by immobilizing the AWO (A = Ag, Bi, Na) nanocrystals on the surface of siligraphene (g-SiC) nanosheets. The g-SiC/AWO composites was synthesized by magnesiothermic synthesis of g-SiC and sonochemical immobilization of tungstates. These new heterojunctions of g-SiC/tungstates show superior photocatalytic activities in the degradation of high concentrations of tetracycline and 97, 98, and 94% of tetracycline were removed by using low amounts of g-SiC/Ag2WO4, g-SiC/Bi2WO6, and g-SiC/Na2WO4 catalysts, respectively. Based on band structures, the band gaps reduce and the photocatalytic activities were extremely enhanced due to the shortening of electron transfer distance through the Z-scheme mechanism. Also, the graphenic structure of g-SiC is another parameter that was effective in improving photocatalytic performance by increasing the electron transfer and decreasing the rate of electron–hole recombination. Furthermore, the π back-bonding of g-SiC with metal atoms increases the electron–hole separation to enhance the photocatalytic activity. Interestingly, g-SiC composites (g-SiC/AWO) showed much higher photocatalytic properties compared to graphene composites (gr/AWO) and can remove the tetracycline even at dark by producing the oxygenated radicals via adsorption of oxygen on the positive charge of Si atoms in siligraphene structure.

Regulation of dopamine forward osmosis membrane via inorganic salt and macro-porous substrates for pharmaceutical concentration

Dopamine (DA) with good designability could self-polymerize into polydopamine (PDA) with various polymerization states in alkaline solution. However, the poor structural controllability of PDA leads to serious PDA hyper-polymers, making DA difficulty to be used as sole aqueous phase monomer during conventional interfacial polymerization (IP) for membrane preparation. In this work, the organic solvent forward osmosis (OSFO) membranes were fabricated via substrate-floating interfacial polymerization (SFIP) method with DA as sole aqueous phase monomer and macro-porous polyether sulfone (PES) membrane with pore size of 0.1–0.22 μm as substrates. Inorganic salt such as NaCl was employed as aqueous phase additive, which not only effectively regulated the oligomeric polymerization state of PDA but also promoted DA diffusion. The macro-porous substrate could enlarge the reaction contact area and relieve the internal concentration polarization in support layer. The resulting OSFO membranes exhibited an excellent ethanol flux of ∼10.70 L m−2 h−1 and lower reverse LiCl flux of ∼0.53 g m−2 h−1, as well as a high tetracycline concentration efficiency of >15 % for 1 h run whatever the tetracycline concentration in the feed (500–2000 mg/L). This work provides new insights into the fabrication of high-performance OSFO membrane for solvent recovery and pharmaceutical concentration.

Photocatalytic synergistic biofilms enhance tetracycline degradation and conversion.

Tetracyclines are refractory pollutants that cause persistent harm to the environment and human health. Therefore, it is urgently necessary to develop methods to promote the efficient degradation and conversion of tetracyclines in wastewater. This report proposes a photobiocatalytic synergistic system involving the coupling of GeO2/Zn-doped phosphotungstic acid hydrate/TiO2 (GeO2/Zn-HPW/TiO2)-loaded photocatalytic optical hollow fibers (POHFs) and an algal-bacterial biofilm. The GeO2/Zn-HPW/TiO2 photocatalyst exhibits a broad absorption edge extending to 1000 nm, as well as high-efficiency photoelectric conversion and electron transfer, which allow the GeO2/Zn-HPW/TiO2-coated POHFs to provide high light intensity to promote biofilm growth. The resulting high photocatalytic activity rapidly and stably reduces the toxicity and increases the biodegradability of tetracycline-containing wastewater. The biofilm enriched with Salinarimonas, Coelastrella sp., and Rhizobium, maintains its activity for the rapid photocatalytic degradation and biotransformation of intermediates to generate the O2 required for photocatalysis. Overall, the synergistic photocatalytic biofilm system developed herein provides an effective and efficient approach for the rapid degradation and conversion of water containing high concentrations of tetracycline.

Novel iron-carbon micro-electrolysis-anoxic/oxic biofilter system for enhanced treatment of tetracycline wastewater: Significant reduction of antibiotic-resistant and pathogenic bacteria

To mitigate the toxicity of tetracycline (TET) to functional microorganisms and avoid the exceeded discharge of tetracycline-resistant bacteria (TRB), a novel combined iron-carbon micro-electrolysis-anoxic/oxic biofilter (Fe–C-AOBF) system for treatment of pharmaceutical wastewater with high TET concentration was successfully established. Results showed that Fe–C-AOBF had the higher maximum tolerated concentration and the stronger degradation ability for TET than normal biological treatment system. When influent COD, NH4–N and TET were 4000, 200 and 100 mg/L, their removal efficiencies via Fe–C-AOBF could reach 96%, 86% and 90%, respectively. Microbial community analysis revealed micro-electrolysis pretreatment in Fe–C-AOBF system improved the microbial diversity compared to up-flow anaerobic/oxic biological aerated filter (UAF–UBAF). The relative abundance of dominate bacteria with tetracycline resistance genes (TRGs) in the biofilm of Fe–C-AOBF, such as Comamonadaceae, Thauera, Sinobacteracea, Acidaminobacter, and Enterobacteriaceae, was also decreased. Moreover, the absolute concentrations of five normal TRGs in effluent of Fe–C-AOBF were reduced by about 16 orders of magnitude as compared to UAF-UBAF. Due to approximately 70% of original TET has been degraded in micro-electrolysis process and lost its selective pressure to microorganisms, Fe–C micro-electrolysis played a key role in restraining the formation and reproduction of TRB and eliminating the potential risk of pathogenic bacteria (e.g., Arocobacter)in AOBF. Fe–C-AOBF system provided an efficient, stable and green method for antibiotic wastewater treatment with the function of inhibiting the emergence of antibiotic-resistant bacteria.

Construction of activated biochar/Bi2WO6 and /Bi2MoO6 composites to enhance adsorption and photocatalysis performance for efficient application in the removal of pollutants and disinfection.

To synergistically enhance the adsorption and photocatalytic performance of Bi2WO6 and Bi2MoO6, using activated biochar (ACB) as substrate, ACB-Bi2WO6 and ACB-Bi2MoO6 composites were facilely prepared by hydrothermal synthesis. Their adsorption-photocatalytic degradation effects on rhodamine B (RhB), tetracycline (TC), and norfloxacin (NOR) were comparatively investigated. Additionally, the effects of environmental factors, wastewater treatment tests, and disinfection were systematically studied, and the enhancement mechanisms and reasons for the degradation differences were highlighted. The results showed that ACB-Bi2WO6 and ACB-Bi2MoO6 were confirmed to form intimately contacted heterojunctions by various advanced characterization techniques. The introduction of ACB narrowed the band-gap energy of Bi2WO6 and Bi2MoO6, and improved the visible light absorption range and specific surface area. The optimal loading ratios of ACB-Bi2WO6 and ACB-Bi2MoO6 were 1:1.06 and 1:0.58, respectively. The removal rate of ACB-Bi2WO6 for high concentrations of RhB (200 mg·L-1), TC and NOR (50 mg·L-1) were 89.15%, 87.27%, and 72.17%, respectively, which were higher than those of ACB-Bi2MoO6 and significantly stronger than those of Bi2WO6 and Bi2MoO6. This was attributed to the more effective inhibition of photogenerated carrier recombination, higher absorbance, and uniform morphology via ACB-Bi2WO6. ·OH and holes were dominant active species in photocatalysis, and the possible photogenerated carrier transfer path is type II heterojunction. Furthermore, ACB-Bi2WO6 possessed good reusability, and the removal of RhB and TC from the actual wastewater exceeded 80.63% and 58.54%, respectively. The sterilization rates of ACB-Bi2WO6 reached 99% and 95% for E. coli and S. aureus within 24 h, respectively. Therefore, ACB-Bi2WO6 was more recommended for environmental applications.

Degradation of tetracycline by visible light over ZnO nanophotocatalyst

BackgroundZnO material can only absorb ultraviolet light. However, tetracycline (TC) can sensitize semiconductors to produce visible light activity. The application of intrinsic ZnO for visible light degradation of TC is a new discovery. MethodsThe ZnO nanostructures were synthesized by the precipitation method with sodium dodecyl sulfate (SDS) as the structure guide. The catalytic activity of intrinsic ZnO to degrade high concentrations of TC under visible light irradiation was investigated. Significant findingsThe addition of SDS changed the morphology of ZnO and reduced its average size to 55.5 nm. In the visible light photocatalytic degradation, SDS also enhanced the adsorption of TC on the surface of ZnO and promoted the formation of TC-SDS/ZnO surface complexes at the defects. The results showed that the degradation rate of TC by SDS/ZnO is 49.0%, which is 2.51 times that of commercial ZnO. UV-Vis DRS proves that TC-SDS/ZnO has visible light response, TC as a photosensitizer absorbs visible light and excites ZnO with visible light response. Radical trapping experiments combined with ESR tests jointly proved that •O2− and •OH play vital roles in the degradation of TC, finally the degradation mechanism was proposed.

Divergent Effects of Antibiotics on Plants and Microbiota in Soils with Contrasting Humus Content

Despite the large number of scientific studies on the effects of antibiotics on soil microorganisms, little is known about the role played by soil organic matter (humus) in the interaction of antibiotics with microorganisms and plants, including the impacts on respiration and growth rate and the implications for nitrogen metabolism, which is an important factor in soil fertility The aim of this study was to analyze the effects of two widely used antibiotics, tetracycline and streptomycin, on microbiotic activity and plant growth in two soils with dissimilar organic carbon content, at the extremes of the fertility spectrum based on humus content. The study used humus-rich (Corg 5.4%) and humus-poor soils (Corg 1.5%) and measured basal respiration, substrate-induced respiration, nitric oxide emission, germination, and growth of white mustard 3 and 60 days after three progressively increasing doses of antibiotics were applied. Tetracycline was found to impair the ecological function of humus-rich soil by reducing denitrification and compromising soil microbial activity, while the effect of streptomycin on humus-poor soil was to reduce nitrification and soil fertility due to nitrogen escape. Both streptomycin and tetracycline increased the microbial biomass and suppressed the growth of white mustard seeds, which indicates an increase in the allelopathic activity of microorganisms in the soil conditions under the influence of antibiotics and their metabolites. Due to the low sorption of streptomycin in humus-poor soils, it poses a great danger to agricultural production, especially in areas of low fertility. In humus-rich soils, high concentrations of tetracycline caused numerous problems, including death of the crop plants. Thus, the effect of antibiotics as well as the more traditional soil pollutants, such as heavy metals, to a large extent, depends on the humus content of soils.

Antibiotic treatment (Tetracycline) effect on bio-efficiency of the larvae honey bee (Apis mellifera jemenatica)

Honey bees are important for ecological health, biodiversity preservation, and crop output. Antimicrobials, like Tetracyclines, are commonly used in agriculture, medicine, and beekeeping, bees might be exposed to Tetracycline residues in the environment either directly or indirectly. This study aimed to determine the effect of antibiotic treatment (Tetracycline) effect on the Bio-efficiency of the larvae honey bee (Apis mellifera jemenatica), when larvae honeybee workers were exposed to different concentrations of it, to see how long they survived after being exposed to it and affected this antibiotic to the histological structure of the midgut. The results demonstrated that the concentration (LC50 = 125.25 μg/ml) of antibiotics Tetracycline leads to kills half of the individuals. Our data indicate that the high concentrations of Tetracycline have a significant effect on the histological composition of the cells of the midgut of honeybee larvae. Antibiotic exposure can negatively impact the health of honey bees, especially Tetracycline because it is the most used antibiotic in apiculture.

N, S co-doped magnetic mesoporous carbon nanosheets for activating peroxymonosulfate to rapidly degrade tetracycline: Synergistic effect and mechanism

Heteroatoms doped carbon materials are widely used in the advanced oxidation process (AOPs) to remove organic pollutants in water due to the synergies effect between different heteroatoms. In this study, a novel kind of N, S co-doped magnetic mesoporous carbon nanosheets (Fe@NS-C) was prepared by simple one-step pyrolysis. Further, the influence of doping amount of S (L-methionine) and N (melamine) on catalytic activity was studied, the optimized sample Fe@NS-C-2-12/PMS showed a satisfying degradation ( 91.07%) for high concentrations of tetracycline (80 mg/L TC) in 10 min, which was attributed to the proper ratio of S content to N content (S(at.%)/ N(at.%)= 0.2097) in the sample could better play its synergistic effect by XPS analysis. The Fe@NS-C-2-12/ PMS system also exhibited satisfactory degradation effects in a wide pH range (3−10) and the existence of inorganic ions and humic acid. Then, the degradation mechanisms were mainly through the non-radical pathway (1O2 and electron transfer) and the major active sites were pyridinic N compared to thiophene S, CO, and Fe-Nx. This study could inspire the design of high-performance active and low-cost heteroatomic doping nano-magnetic catalysts for PMS-based waste treatment.

Phytotoxicity of Tetracycline and Amoxicillin on Vigna radiata and its Remediation Potential in Hydroponic System

The current study aimed to evaluate the phytotoxicity of tetracycline and amoxicillin on Vigna radiata and its remediation potential in hydroponic system. Germinated seeds of Vig-na radiata were planted with varying concentra-tions of tetracycline and amoxicillin (150 – 500 mg L−1) in triplicates (n=3) for three weeks. Tox-icity biomarkers, i.e. changes in plant biomass, photosynthetic pigment, phenol, flavonoid con-tent and antioxidative enzymes were estimated after completion of 3 weeks. The results illus-trated that high tetracycline concentration (500 mg L-1) in hoagland media resulted decrease in total chlorophyll content (3.045- 2.252 mg total chlorophyll /g tissue) while in case of amoxicillin, chlorophyll content was increased (5.18 - 7.309 mg total chlorophyll /g tissue). Carotenoid, Total flavonoid and phenolic content, were also sig-nificantly (p < 0.05) reduced due to toxicity of these antibiotics. Antioxidant enzyme like cata-lase showed 7.22 % degradation in their activity with highest concentration (500 mg kg-1) of tet-racycline and 27.3 % degradation was found in case of amoxicillin. Glutathione peroxidase ac-tivity was also decreased in both of the cases. Subsequently, the Vigna radiata showed 63% remediation potential with tetracycline and 93 % in case of amoxicillin. Hence, overall results indicate that, the phytoremediation rate shown by Vigna radiata is very promising and these antibiotics also showed its toxicological impact on plants.