scholarly journals Environmental fate of tetracycline antibiotics: degradation pathway mechanisms, challenges, and perspectives

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Ahmad Fiaz ◽  
Daochen Zhu ◽  
Jianzhong Sun

AbstractTetracycline pollution is a growing global threat to aquatic and terrestrial biodiversity due to its unprecedented use in aquaculture, livestock, and human disease prevention. The influx of tetracycline may annihilate the microbial ecology structure in the environment and pose a severe threat to humans by disturbing the food chain. Although significant research data are available in the literature on various aspects of tetracycline, including detection techniques, degradation mechanisms, degradation products, and policy statements to curtail the issue, there is a scarcity of a report to compile the recent data in the literature for better analysis and comparison by the policymakers. To achieve this paucity in knowledge, the current study aims at collecting data on the available degradation strategies, mechanisms involved in biodegradable and non-biodegradable routes, the main factor affecting degradation strategies, compile novel detection techniques of tetracycline antibiotics in the environment, discuss antibiotic resistance genes and their potential role in degradation. Finally, limitations in the current bioremediation techniques and the future prospects are discussed with pointers for the decision-makers for a safer environment.

Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 874
Author(s):  
Periyasamy Sivalingam ◽  
John Poté ◽  
Kandasamy Prabakar

Over the past decades, the rising antibiotic resistance bacteria (ARB) are continuing to emerge as a global threat due to potential public health risk. Rapidly evolving antibiotic resistance and its persistence in the environment, have underpinned the need for more studies to identify the possible sources and limit the spread. In this context, not commonly studied and a neglected genetic material called extracellular DNA (eDNA) is gaining increased attention as it can be one of the significant drivers for transmission of extracellular ARGS (eARGs) via horizontal gene transfer (HGT) to competent environmental bacteria and diverse sources of antibiotic-resistance genes (ARGs) in the environment. Consequently, this review highlights the studies that address the environmental occurrence of eDNA and encoding eARGs and its impact on the environmental resistome. In this review, we also brief the recent dedicated technological advancements that are accelerating extraction of eDNA and the efficiency of treatment technologies in reducing eDNA that focuses on environmental antibiotic resistance and potential ecological health risk.


Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Yu Li ◽  
Zeling Xu ◽  
Wenkai Han ◽  
Huiluo Cao ◽  
Ramzan Umarov ◽  
...  

Abstract Background The spread of antibiotic resistance has become one of the most urgent threats to global health, which is estimated to cause 700,000 deaths each year globally. Its surrogates, antibiotic resistance genes (ARGs), are highly transmittable between food, water, animal, and human to mitigate the efficacy of antibiotics. Accurately identifying ARGs is thus an indispensable step to understanding the ecology, and transmission of ARGs between environmental and human-associated reservoirs. Unfortunately, the previous computational methods for identifying ARGs are mostly based on sequence alignment, which cannot identify novel ARGs, and their applications are limited by currently incomplete knowledge about ARGs. Results Here, we propose an end-to-end Hierarchical Multi-task Deep learning framework for ARG annotation (HMD-ARG). Taking raw sequence encoding as input, HMD-ARG can identify, without querying against existing sequence databases, multiple ARG properties simultaneously, including if the input protein sequence is an ARG, and if so, what antibiotic family it is resistant to, what resistant mechanism the ARG takes, and if the ARG is an intrinsic one or acquired one. In addition, if the predicted antibiotic family is beta-lactamase, HMD-ARG further predicts the subclass of beta-lactamase that the ARG is resistant to. Comprehensive experiments, including cross-fold validation, third-party dataset validation in human gut microbiota, wet-experimental functional validation, and structural investigation of predicted conserved sites, demonstrate not only the superior performance of our method over the state-of-art methods, but also the effectiveness and robustness of the proposed method. Conclusions We propose a hierarchical multi-task method, HMD-ARG, which is based on deep learning and can provide detailed annotations of ARGs from three important aspects: resistant antibiotic class, resistant mechanism, and gene mobility. We believe that HMD-ARG can serve as a powerful tool to identify antibiotic resistance genes and, therefore mitigate their global threat. Our method and the constructed database are available at http://www.cbrc.kaust.edu.sa/HMDARG/.


BIBECHANA ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 214-230
Author(s):  
Narendra Kumar Chaudhary ◽  
Biswash Guragain ◽  
Siyanand Kumar Chaudhary ◽  
Parashuram Mishra

The discovery of new chemotherapeutics with novel bioactivities and functionalities to fight current emerging diseases has become the most significant research in pharmaceutical science. Schiff bases are versatile pharmacophores that can form complexes by chelation with metals of different oxidation states. Over a few decades of intensive research on metal-based drugs, Schiff base metal complexes have been considered as the active field of research in coordination chemistry, owing to their valuable applications in various fields of science. As therapeutic drugs, they have potential applications as antibiotic, antimicrobial, antitumor, antiviral, anti-inflammatory, analgesic, antifungal, and many more. There has been a global threat of drug resistance in medical science in recent years because most of the pathogenic organisms are developing the ability to deactivate drug substances. For this reason, it requires urgent attention from chemical and pharmaceutical scientists to address the severe challenges of multidrug resistance. This review summarizes the current developments in the last few decades' research on the chemotherapeutic activities of Schiff base metal complexes. BIBECHANA 18 (2021) 214-230


2008 ◽  
Vol 3 (5) ◽  
pp. 1934578X0800300 ◽  
Author(s):  
Man Xu ◽  
Jian Han ◽  
Hui-feng Li ◽  
Li Fan ◽  
Ai-hua Liu ◽  
...  

The stability of salvianolic acid B and total phenolic acids from Salvia miltiorrhiza in water solutions at different temperatures, in buffered aqueous solutions at different pHs and in biological fluids, including simulated gastric and intestinal fluids, were investigated in vitro. The results showed that the degradation of salvianolic acid B was pH- and temperature-dependent. Furthermore, structures of the degradation products of salvianolic acid B and total phenolic acids were elucidated by liquid chromatography-electrospray ion trap mass spectrometry and analysis of the degraded solutions revealed seventeen degradation products. The possible degradation pathway of salvianolic acid B is proposed.


2002 ◽  
Vol 68 (1) ◽  
pp. 166-172 ◽  
Author(s):  
Diane Fournier ◽  
Annamaria Halasz ◽  
Jim Spain ◽  
Petr Fiurasek ◽  
Jalal Hawari

ABSTRACT Rhodococcus sp. strain DN22 can convert hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to nitrite, but information on degradation products or the fate of carbon is not known. The present study describes aerobic biodegradation of RDX (175 μM) when used as an N source for strain DN22. RDX was converted to nitrite (NO2 −) (30%), nitrous oxide (N2O) (3.2%), ammonia (10%), and formaldehyde (HCHO) (27%), which later converted to carbon dioxide. In experiments with ring-labeled [15N]-RDX, gas chromatographic/mass spectrophotometric (GC/MS) analysis revealed N2O with two molecular mass ions: one at 44 Da, corresponding to 14N14NO, and the second at 45 Da, corresponding to 15N14NO. The nonlabeled N2O could be formed only from -NO2, whereas the 15N-labeled one was presumed to originate from a nitramine group (15N-14NO2) in RDX. Liquid chromatographic (LC)-MS electrospray analyses indicated the formation of a dead end product with a deprotonated molecular mass ion [M-H] at 118 Da. High-resolution MS indicated a molecular formula of C2H5N3O3. When the experiment was repeated with ring-labeled [15N]-RDX, the [M-H] appeared at 120 Da, indicating that two of the three N atoms in the metabolite originated from the ring in RDX. When [U-14C]-RDX was used in the experiment, 64% of the original radioactivity in RDX incorporated into the metabolite with a molecular weight (MW) of 119 (high-pressure LC/radioactivity) and 30% in 14CO2 (mineralization) after 4 days of incubation, suggesting that one of the carbon atoms in RDX was converted to CO2 and the other two were incorporated in the ring cleavage product with an MW of 119. Based on the above stoichiometry, we propose a degradation pathway for RDX based on initial denitration followed by ring cleavage to formaldehyde and the dead end product with an MW of 119.


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