Drinking water biofiltration: Removal of antibiotics and behaviour of antibiotic resistance genes

This research investigated the effectiveness of biofiltration systems for the attenuation of antibiotics and antibiotic resistance genes (ARGs) from drinking water. Five antibiotics, including amoxicillin, clarithromycin, oxytetracycline, sulfamethoxazole, and trimethoprim, and the relevant resistance genes (blaCTX-M, blaOXA-1, blaTEM, ermB, tetA, tetG, tetQ, tetW, tetX, sul 1, sul 2, dfrA1 and dfrA12) as well as integrase genes (intI 1 and intI 2) were targeted. In addition, the role the biofilm plays as a gene transfer site was also investigated. Both chemical (LC-MS/MS) and molecular biology (real-time qPCR, high-throughput qPCR and 16S rRNA amplicon sequencing) methodologies were used. A total of three biofiltration experiments using sand, granular activated carbon (GAC) and anthracite as filter media were set-up at bench-scale. Results showed that the target antibiotics were substantially removed (> 90%) by GAC-associated biofilters and partially removed (< 20%) by sand and anthracite-sand dual media biofilters. The position of GAC layer within the sand filter bed showed no effect on antibiotic removal. The absolute abundance of ARGs decreased (1.0-log reduction on average) after biofiltration, while ARGs’ normalised copy number remained unchanged or showed an increasing trend in the filtered water, especially when exposed to the target antibiotics, indicating that the biofilters did not contribute greatly to the elimination of ARG pollution from the feedwater despite the effective removal of antibiotics. Exposure to the target antibiotics affected the bacterial community in biofilm samples and the differences in bacterial community structure were correlated with the changes in the resistome. Plasmid conjugative transfer experiment based on biofiltration showed that the GAC media is more conducive to the horizontal transfer of ARGs in biofilms and the transfer occurred more frequently in biofilms than in the influents and effluents. Overall, the results of this study could enhance our understanding of the prevalence of ARGs during drinking water treatment

Optimization of the cry1Ah1 Sequence Enhances the Hyper-Resistance of Transgenic Poplars to Hyphantria cunea

Increased expression of the insect control protein genes of Bacillus thuringiensis in Populus has been critical to the development of genetically improved plants with agronomically acceptable levels of insect resistance. Bacillus thuringiensis (Cry1Ah1) proteins with highly specific toxicity against Hyphantria cunea were screened using an indoor bioactivity assay to obtain hyper-resistant transgenic poplars. Then, the Cry1Ah1 sequence was optimized and transformed according to the optimal codon in poplar using software of our own design (http://120.79.60.226:8080/u/chen/w/codonpoplar). A vector was constructed to transform poplar NL895. The Cry1Ah1 gene was transformed to poplar NL895 and six transgenic lines were obtained. The expression and insecticidal effect of the Cry1Ah1 gene in transgenic poplar were evaluated by PCR and ELISA, and the specific indoor activity and field insecticidal activity against H. cunea were compared with a control. We concluded that the insecticidal activity of the transgenic NL895 was significantly better against lower instar larvae of H. cunea than against higher instar larvae. The mortality and pupation rates clearly differed among the various instar larvae and between transgenic and non-transgenic poplar. We obtained poplar seedlings with hyper-resistance to H. cunea by screening Bt genes and optimizing their genetic sequence

Antibiotic resistance genes and the association with bacterial community in biofilms occurring during the drinking water granular activated carbon (GAC) sandwich biofiltration

The granular activated carbon (GAC) sandwich modification to slow sand filtration could be considered as a promising technology for improved drinking water quality. Biofilms developed on sand and GAC surfaces are expected to show a functional diversity during the biofiltration. Bench-scale GAC sandwich biofilters were set-up and run continuously with and without antibiotic exposure. Surface sand (the schmutzdecke) and GAC biofilms were sampled and subject to high-throughput qPCR for antibiotic resistance gene (ARG) analysis and 16 S rRNA amplicon sequencing. Similar diversity of ARG profile was found in both types of biofilms, suggesting that all ARG categories decreased in richness along the filter bed. In general, surface sand biofilm remained the most active layer with regards to the richness and abundance of ARGs, where GAC biofilms showed slightly lower ARG risks. Network analysis suggested that 10 taxonomic genera were implicated as possible ARG hosts, among which Nitrospira, Methyloversatilis and Methylotenera showed the highest correlation. Overall, this study was the first attempt to consider the whole structure of the GAC sandwich biofilter and results from this study could help to further understand the persistence of ARGs and their association with the microbial community in drinking water biofiltration system

Utjecaj velikih i malih molekula emulgatora na svojstva nanoemulzija β-karotena, pripremljenih homogenizacijom pod visokim pritiskom

Oil-in-water (O/W) nanoemulsion allows the preparation of lipophilic nutrients such as carotenoids in liquid form, which may improve their bioavailability and broaden applications. In the present study, polyoxyethylene sorbitan monolaurate (Tween 20, TW-20), decaglycerol monolaurate (DML), octenyl succinate starch (OSS), whey protein isolate (WPI), and finally a blend of TW-20 and WPI (1 % by mass) have been tested for the preparation of β-carotene nanoemulsions. Interfacial tension, droplet size, zeta potential, microstructures observed by atomic force microscopy (AFM), stability of the emulsion and β-carotene have been compared. Results show that nanoemulsions stabilized with TW-20 and DML had smaller droplet size, but relatively poorer stability, compared with the ones stabilized with OSS and WPI (p0.05).Nanoemulzije ulja u vodi omogućuju pripremu lipofilnih hranjivih tvari, kao što su karotenoidi u tekućem obliku, čime se povećava njihova biološka pristupačnost i primjena. U radu je istražena mogućnost pripreme nanoemulzija β-karotena pomoću ovih emulgatora: polioksietilen sorbitan monolaurata (Tween 20), dekaglicerol monolaurata, škrob natrijeva oktenil sukcinata, izolata pšeničnih proteina i 1 %-tne smjese Tween 20 i izolata pšeničnih proteina. Uspoređena je međupovršinska napetost dobivenih emulzija, veličina kapljica, zeta- potencijal, mikrostruktura (utvrđena pomoću mikroskopa atomskih sila), te stabilnost emulzija i β-karotena. Rezultati pokazuju da nanoemulzije stabilizirane s Tween 20 i dekaglicerol monolauratom imaju manje kapljice, ali slabiju stabilnost od emulzija stabiliziranih sa škrob natrijevim oktenil sukcinatom i izolatom pšeničnih proteina (p0,05)

Impacts of Antibiotic Residues in the Environment on Bacterial Resistance and Human Health in Eastern China: An Interdisciplinary Mixed-Methods Study Protocol

Antibiotic resistance is a global health challenge that threatens human and animal lives, especially among low-income and vulnerable populations in less-developed countries. Its multi-factorial nature requires integrated studies on antibiotics and resistant bacteria in humans, animals, and the environment. To achieve a comprehensive understanding of the situation and management of antibiotic use and environmental transmission, this paper describes a study protocol to document human exposure to antibiotics from major direct and indirect sources, and its potential health outcomes. Our mixed-methods approach addresses both microbiological and pathogen genomics, and epidemiological, geospatial, anthropological, and sociological aspects. Implemented in two rural residential areas in two provinces in Eastern China, linked sub-studies assess antibiotic exposure in population cohorts through household surveys, medicine diaries, and biological sampling; identify the types and frequencies of antibiotic resistance genes in humans and food-stock animals; quantify the presence of antibiotic residues and antibiotic resistance genes in the aquatic environment, including wastewater; investigate the drivers and behaviours associated with human and livestock antibiotic use; and analyse the national and local policy context, to propose strategies and systematic measurements for optimising and monitoring antibiotic use. As a multidisciplinary collaboration between institutions in the UK and China, this study will provide an in-depth understanding of the influencing factors and allow comprehensive awareness of the complexity of AMR and antibiotic use in rural Eastern China

Insights into Adaptations to a Near- Obligate Nematode Endoparasitic Lifestyle from the Finished Genome of Drechmeria coniospora

Nematophagous fungi employ three distinct predatory strategies: nematode trapping, parasitism of females and eggs, and endoparasitism. While endoparasites play key roles in controlling nematode populations in nature, their application for integrated pest management is hindered by the limited understanding of their biology. We present a comparative analysis of a high quality finished genome assembly of Drechmeria coniospora, a model endoparasitic nematophagous fungus, integrated with a transcriptomic study. Adaptation of D. coniospora to its almost completely obligate endoparasitic lifestyle led to the simplification of many orthologous gene families involved in the saprophytic trophic mode, while maintaining orthologs of most known fungal pathogen-host interaction proteins, stress response circuits and putative effectors of the small secreted protein type. The need to adhere to and penetrate the host cuticle led to a selective radiation of surface proteins and hydrolytic enzymes. Although the endoparasite has a simplified secondary metabolome, it produces a novel peptaibiotic family that shows antibacterial, antifungal and nematicidal activities. Our analyses emphasize the basic malleability of the D. coniospora genome: loss of genes advantageous for the saprophytic lifestyle; modulation of elements that its cohort species utilize for entomopathogenesis; and expansion of protein families necessary for the nematode endoparasitic lifestyle