# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 605 | 0 | 0.9872 | Conservation and diversity of the IrrE/DdrO-controlled radiation response in radiation-resistant Deinococcus bacteria. The extreme radiation resistance of Deinococcus bacteria requires the radiation-stimulated cleavage of protein DdrO by a specific metalloprotease called IrrE. DdrO is the repressor of a predicted radiation/desiccation response (RDR) regulon, composed of radiation-induced genes having a conserved DNA motif (RDRM) in their promoter regions. Here, we showed that addition of zinc ions to purified apo-IrrE, and short exposure of Deinococcus cells to zinc ions, resulted in cleavage of DdrO in vitro and in vivo, respectively. Binding of IrrE to RDRM-containing DNA or interaction of IrrE with DNA-bound DdrO was not observed. The data are in line with IrrE being a zinc peptidase, and indicate that increased zinc availability, caused by oxidative stress, triggers the in vivo cleavage of DdrO unbound to DNA. Transcriptomics and proteomics of Deinococcus deserti confirmed the IrrE-dependent regulation of predicted RDR regulon genes and also revealed additional members of this regulon. Comparative analysis showed that the RDR regulon is largely well conserved in Deinococcus species, but also showed diversity in the regulon composition. Notably, several RDR genes with an important role in radiation resistance in Deinococcus radiodurans, for example pprA, are not conserved in some other radiation-resistant Deinococcus species. | 2017 | 28397370 |
| 9364 | 1 | 0.9866 | Predictable properties of fitness landscapes induced by adaptational tradeoffs. Fitness effects of mutations depend on environmental parameters. For example, mutations that increase fitness of bacteria at high antibiotic concentration often decrease fitness in the absence of antibiotic, exemplifying a tradeoff between adaptation to environmental extremes. We develop a mathematical model for fitness landscapes generated by such tradeoffs, based on experiments that determine the antibiotic dose-response curves of Escherichia coli strains, and previous observations on antibiotic resistance mutations. Our model generates a succession of landscapes with predictable properties as antibiotic concentration is varied. The landscape is nearly smooth at low and high concentrations, but the tradeoff induces a high ruggedness at intermediate antibiotic concentrations. Despite this high ruggedness, however, all the fitness maxima in the landscapes are evolutionarily accessible from the wild type. This implies that selection for antibiotic resistance in multiple mutational steps is relatively facile despite the complexity of the underlying landscape. | 2020 | 32423531 |
| 567 | 2 | 0.9865 | A novel bipartite antitermination system widespread in conjugative elements of Gram-positive bacteria. Transcriptional regulation allows adaptive and coordinated gene expression, and is essential for life. Processive antitermination systems alter the transcription elongation complex to allow the RNA polymerase to read through multiple terminators in an operon. Here, we describe the discovery of a novel bipartite antitermination system that is widespread among conjugative elements from Gram-positive bacteria, which we named conAn. This system is composed of a large RNA element that exerts antitermination, and a protein that functions as a processivity factor. Besides allowing coordinated expression of very long operons, we show that these systems allow differential expression of genes within an operon, and probably contribute to strict regulation of the conjugation genes by minimizing the effects of spurious transcription. Mechanistic features of the conAn system are likely to decisively influence its host range, with important implications for the spread of antibiotic resistance and virulence genes. | 2021 | 33999173 |
| 6788 | 3 | 0.9865 | Release and Constancy of an Antibiotic Resistance Gene in Seawater under Grazing Stress by Ciliates and Heterotrophic Nanoflagellates. Extracellular DNA (exDNA) is released from bacterial cells through various processes. The antibiotic resistance genes (ARGs) coded on exDNA may be horizontally transferred among bacterial communities by natural transformation. We quantitated the released/leaked tetracycline resistance gene, tet(M) over time under grazing stress by ciliates and heterotrophic nanoflagellates (HNFs), and found that extracellular tet(M) (ex-tetM) increased with bacterial grazing. Separate microcosms containing tet(M)-possessing bacteria with ciliates or HNFs were prepared. The copy number of ex-tetM in seawater in the ciliate microcosm rapidly increased until 3 d after the incubation, whereas that in the HNF microcosm showed a slower increase until 20 d. The copy number of ex-tetM was stable in both cases throughout the incubation period, suggesting that extracellular ARGs are preserved in the environment, even in the presence of grazers. Additionally, ARGs in bacterial cells were constant in the presence of grazers. These results suggest that ARGs are not rapidly extinguished in a marine environment under grazing stress. | 2017 | 28592722 |
| 574 | 4 | 0.9865 | Pyrroloquinoline quinone and a quinoprotein kinase support γ-radiation resistance in Deinococcus radiodurans and regulate gene expression. Deinococcus radiodurans is known for its extraordinary resistance to various DNA damaging agents including γ-radiation and desiccation. The pqqE:cat and Δdr2518 mutants making these cells devoid of pyrroloquinoline quinone (PQQ) and a PQQ inducible Ser/Thr protein kinase, respectively, became sensitive to γ-radiation. Transcriptome analysis of these mutants showed differential expression of the genes including those play roles in oxidative stress tolerance and (DSB) repair in D. radiodurans and in genome maintenance and stress response in other bacteria. Escherichia coli cells expressing DR2518 and PQQ showed improved resistance to γ-radiation, which increased further when both DR2518 and PQQ were present together. Although, profiles of genes getting affected in these mutants were different, there were still a few common genes showing similar expression trends in both the mutants and some others as reported earlier in oxyR and pprI mutant of this bacterium. These results suggested that PQQ and DR2518 have independent roles in γ-radiation resistance of D. radiodurans but their co-existence improves radioresistance further, possibly by regulating differential expression of the genes important for bacterial response to oxidative stress and DNA damage. | 2013 | 22961447 |
| 8620 | 5 | 0.9864 | Changes in Microbiome Confer Multigenerational Host Resistance after Sub-toxic Pesticide Exposure. The gut is a first point of contact with ingested xenobiotics, where chemicals are metabolized directly by the host or microbiota. Atrazine is a widely used pesticide, but the role of the microbiome metabolism of this xenobiotic and the impact on host responses is unclear. We exposed successive generations of the wasp Nasonia vitripennis to subtoxic levels of atrazine and observed changes in the structure and function of the gut microbiome that conveyed atrazine resistance. This microbiome-mediated resistance was maternally inherited and increased over successive generations, while also heightening the rate of host genome selection. The rare gut bacteria Serratia marcescens and Pseudomonas protegens contributed to atrazine metabolism. Both of these bacteria contain genes that are linked to atrazine degradation and were sufficient to confer resistance in experimental wasp populations. Thus, pesticide exposure causes functional, inherited changes in the microbiome that should be considered when assessing xenobiotic exposure and as potential countermeasures to toxicity. | 2020 | 32023487 |
| 566 | 6 | 0.9863 | Characterizing Transcriptional Interference between Converging Genes in Bacteria. Antisense transcription is common in naturally occurring genomes and is increasingly being used in synthetic genetic circuitry as a tool for gene expression control. Mutual influence on the expression of convergent genes can be mediated by antisense RNA effects and by transcriptional interference (TI). We aimed to quantitatively characterize long-range TI between convergent genes with untranslated intergenic spacers of increasing length. After controlling for antisense RNA-mediated effects, which contributed about half of the observed total expression inhibition, the TI effect was modeled. To achieve model convergence, RNA polymerase processivity and collision resistance were assumed to be modulated by ribosome trailing. The spontaneous transcription termination rate in regions of untranslated DNA was experimentally determined. Our modeling suggests that an elongating RNA polymerase with a trailing ribosome is about 13 times more likely to resume transcription than an opposing RNA polymerase without a trailing ribosome, upon head-on collision of the two. | 2019 | 30717589 |
| 9371 | 7 | 0.9862 | Coevolutionary history of predation constrains the evolvability of antibiotic resistance in prey bacteria. Understanding how the historical contingency of biotic interactions shapes the evolvability of bacterial populations is imperative for the predictability of the eco-evolutionary dynamics of microbial communities. While microbial predators like Myxococcus xanthus influence the frequency of antibiotic-resistant bacteria in nature, the effect of adaptation to the presence of predators on the evolvability of prey bacteria to future stressors is unclear. Hence, to understand the influence of the coevolutionary history of predation on the evolvability of antibiotic resistance, we propagated variants of E. coli, pre-adapted to distinct biotic and abiotic conditions, in gradually increasing concentrations of antibiotics. We show that pre-adaptation to predators limits the evolution of a high degree of antibiotic resistance. Moreover, lower degree of resistance in the evolved strains also incurs reduced fitness costs while preserving their ancestral ability to resist predation. Together, we demonstrate that the history of biotic interactions can strongly influence the evolvability of bacteria. | 2025 | 40461734 |
| 8303 | 8 | 0.9862 | Spaceflight Modifies Escherichia coli Gene Expression in Response to Antibiotic Exposure and Reveals Role of Oxidative Stress Response. Bacteria grown in space experiments under microgravity conditions have been found to undergo unique physiological responses, ranging from modified cell morphology and growth dynamics to a putative increased tolerance to antibiotics. A common theory for this behavior is the loss of gravity-driven convection processes in the orbital environment, resulting in both reduction of extracellular nutrient availability and the accumulation of bacterial byproducts near the cell. To further characterize the responses, this study investigated the transcriptomic response of Escherichia coli to both microgravity and antibiotic concentration. E. coli was grown aboard International Space Station in the presence of increasing concentrations of the antibiotic gentamicin with identical ground controls conducted on Earth. Here we show that within 49 h of being cultured, E. coli adapted to grow at higher antibiotic concentrations in space compared to Earth, and demonstrated consistent changes in expression of 63 genes in response to an increase in drug concentration in both environments, including specific responses related to oxidative stress and starvation response. Additionally, we find 50 stress-response genes upregulated in response to the microgravity when compared directly to the equivalent concentration in the ground control. We conclude that the increased antibiotic tolerance in microgravity may be attributed not only to diminished transport processes, but also to a resultant antibiotic cross-resistance response conferred by an overlapping effect of stress response genes. Our data suggest that direct stresses of nutrient starvation and acid-shock conveyed by the microgravity environment can incidentally upregulate stress response pathways related to antibiotic stress and in doing so contribute to the increased antibiotic stress tolerance observed for bacteria in space experiments. These results provide insights into the ability of bacteria to adapt under extreme stress conditions and potential strategies to prevent antimicrobial-resistance in space and on Earth. | 2018 | 29615983 |
| 8621 | 9 | 0.9861 | Effects of symbiotic bacteria on chemical sensitivity of Daphnia magna. The crustacean zooplankton Daphnia magna has been widely used for chemical toxicity tests. Although abiotic factors have been well documented in ecotoxicological test protocols, biotic factors that may affect the sensitivity to chemical compounds remain limited. Recently, we identified symbiotic bacteria that are critical for the growth and reproduction of D. magna. The presence of symbiotic bacteria on Daphnia raised the question as to whether these bacteria have a positive or negative effect on toxicity tests. In order to evaluate the effects of symbiotic bacteria on toxicity tests, bacteria-free Daphnia were prepared, and their chemical sensitivities were compared with that of Daphnia with symbiotic bacteria based on an acute immobilization test. The Daphnia with symbiotic bacteria showed higher chemical resistance to nonylphenol, fenoxycarb, and pentachlorophenol than bacteria-free Daphnia. These results suggested potential roles of symbiotic bacteria in the chemical resistance of its host Daphnia. | 2017 | 28292585 |
| 7673 | 10 | 0.9860 | Effects of ex situ conservation on diversity and function of the gut microbiota of the Tibetan wild ass (Equus kiang). Ex situ conservation is the main method for the protection of endangered wildlife. To explore the effect of ex situ conservation on the gut microbiota of the kiang (Equus kiang), metagenomic sequencing combined with bioinformatics analysis was used to investigate the composition and function of the gut microbiota of the kiang. The results showed that ex situ conservation not only protected wildlife, but also affected the composition and function of gut microbiota, as well as the health of animals. In the zoo, the ratio of the relative abundance of Firmicutes to that of Bacteroidetes (F/B) is higher, clusters of potentially pathogenic bacteria (such as Catonella, Catonella, and Mycoplasma) are more numerous, the abundance of resistance genes is higher, and the abundance of metabolic functions is increased. The dynamic changes of the gut microbiota also played an important role in the nutritional absorption, energy metabolism, and environmental adaptation of the kiang. Improving the rearing environment and increasing food diversity play important roles for increasing the diversity of gut microbiota, reducing the spread of potentially pathogenic bacteria, and reducing diseases. In the wild, especially in winter and in food-deficient areas, food supplementation can enhance the gut microbial homeostasis of wild animals and reduce the impact of crises. In depth studies of the gut microbial function of wildlife have important implications for improving ex situ conservation. | 2023 | 37231976 |
| 8658 | 11 | 0.9860 | Microplastic exposure reshapes the virome and virus-bacteria networks with implications for immune regulation in Mytilus coruscus. Microplastic pollution has emerged as a critical environmental concern, yet its impacts on host-associated viral communities and immune balance in marine bivalves remain largely unexplored. In this study, Mytilus coruscus individuals were exposed to microplastics in situ for seven days. Virome sequencing and bioinformatic analyses revealed that microplastic exposure induced divergent responses in DNA and RNA viral communities. DNA viromes exhibited suppressed diversity and downregulation of core viral metabolic pathways, potentially reflecting reduced viral replication capacity under host immune stress. In contrast, RNA viromes displayed metabolic activation and functional shifts, including enriched glycan and nucleotide metabolism, possibly linked to enhanced viral activity or immune evasion. Phage-bacteria interaction networks were also restructured, showing increased associations with opportunistic pathogens such as Vibrio cholerae and Enterobacter, potentially affecting immune surveillance. Furthermore, the expression of antibiotic resistance genes (ARGs) in viral genomes was differentially regulated, suggesting pollutant-induced microbial selection that may challenge host immune resilience. These findings suggest that microplastics not only reshape virome composition and metabolic functions but also influence virus-mediated immune interactions, with important implications for disease susceptibility and immune homeostasis in filter-feeding shellfish. | 2025 | 41056669 |
| 9368 | 12 | 0.9860 | Gene inversion potentiates bacterial evolvability and virulence. Most bacterial genes are encoded on the leading strand, co-orienting the movement of the replication machinery with RNA polymerases. This bias reduces the frequency of detrimental head-on collisions between the two machineries. The negative outcomes of these collisions should lead to selection against head-on alleles, maximizing genome co-orientation. Our findings challenge this model. Using the GC skew calculation, we reveal the evolutionary inversion record of all chromosomally encoded genes in multiple divergent bacterial pathogens. Against expectations, we find that a large number of co-oriented genes have inverted to the head-on orientation, presumably increasing the frequency of head-on replication-transcription conflicts. Furthermore, we find that head-on genes, (including key antibiotic resistance and virulence genes) have higher rates of non-synonymous mutations and are more frequently under positive selection (dN/dS > 1). Based on these results, we propose that spontaneous gene inversions can increase the evolvability and pathogenic capacity of bacteria through head-on replication-transcription collisions. | 2018 | 30405125 |
| 551 | 13 | 0.9860 | virK and mig-14 constitute a PhoP-dependent operon and contribute to the intracellular survival and polymyxin B resistance of Salmonella Typhi. In bacteria, adjacent and functionally similar genes are typically transcribed as operons. The virulence genes virK and mig-14 are acquired through horizontal gene transfer in Salmonella. Previous studies have reported that these two genes have similar functions in terms of bacterial survival within macrophages and resistance to antimicrobial peptides. Nevertheless, the specific expression characteristics of the two genes remain unclear. This study revealed that virK and mig-14 were transcribed as a single operon in Salmonella Typhi. The virK-mig-14 operon was found to be activated under conditions of early hyperosmotic stress and polymyxin B stimulation, and its activation was dependent on the presence of the regulator PhoP. The luminescence assay demonstrated that the activity of the virK promoter was markedly elevated in an environment conducive to operon activation, whereas the mig-14 promoter exhibited no discernible change. This suggests that mig-14 is predominantly transcribed as a component of the operon. In the PhoP activation environment, which has a mildly acidic pH, low Mg(2+) levels, and intracellular macrophages, the virK-mig-14 operon exhibited significant activation. The absence of virK or mig-14 resulted in the impaired survival of Salmonella Typhi within macrophages and decreased its tolerance to polymyxin B. Collectively, this study shows that virK and mig-14 constitute an operon whose activation depends on PhoP and that it promotes S. Typhi's survival in macrophages and resistance to polymyxin B. | 2025 | 40345346 |
| 8529 | 14 | 0.9859 | Investigating and Modeling the Regulation of Extracellular Antibiotic Resistance Gene Bioavailability by Naturally Occurring Nanoparticles. Extracellular antibiotic resistance genes (eARGs) are widespread in the environment and can genetically transform bacteria. This work examined the role of environmentally relevant nanoparticles (NPs) in regulating eARG bioavailability. eARGs extracted from antibiotic-resistant B. subtilis were incubated with nonresistant recipient B. subtilis cells. In the mixture, particle type (either humic acid coated nanoparticles (HASNPs) or their micron-sized counterpart (HASPs)), DNase I concentration, and eARG type were systematically varied. Transformants were counted on selective media. Particles decreased bacterial growth and eARG bioavailability in systems without nuclease. When DNase I was present (≥5 μg/mL), particles increased transformation via chromosomal (but not plasmid-borne) eARGs. HASNPs increased transformation more than HASPs, indicating that the smaller nanoparticle with greater surface area per volume is more effective in increasing eARG bioavailability. These results were also modeled via particle aggregation theory, which represented eARG-bacteria interactions as transport leading to collision, followed by attachment. Using attachment efficiency as a fitting factor, the model predicted transformant concentrations within 35% of experimental data. These results confirm the ability of NPs to increase eARG bioavailability and suggest that particle aggregation theory may be a simplified and suitable framework to broadly predict eARG uptake. | 2022 | 35853206 |
| 9370 | 15 | 0.9859 | 'Blooming' in the gut: how dysbiosis might contribute to pathogen evolution. Hundreds of bacterial species make up the mammalian intestinal microbiota. Following perturbations by antibiotics, diet, immune deficiency or infection, this ecosystem can shift to a state of dysbiosis. This can involve overgrowth (blooming) of otherwise under-represented or potentially harmful bacteria (for example, pathobionts). Here, we present evidence suggesting that dysbiosis fuels horizontal gene transfer between members of this ecosystem, facilitating the transfer of virulence and antibiotic resistance genes and thereby promoting pathogen evolution. | 2013 | 23474681 |
| 606 | 16 | 0.9859 | Coexistence of SOS-Dependent and SOS-Independent Regulation of DNA Repair Genes in Radiation-Resistant Deinococcus Bacteria. Deinococcus bacteria are extremely resistant to radiation and able to repair a shattered genome in an essentially error-free manner after exposure to high doses of radiation or prolonged desiccation. An efficient, SOS-independent response mechanism to induce various DNA repair genes such as recA is essential for radiation resistance. This pathway, called radiation/desiccation response, is controlled by metallopeptidase IrrE and repressor DdrO that are highly conserved in Deinococcus. Among various Deinococcus species, Deinococcus radiodurans has been studied most extensively. Its genome encodes classical DNA repair proteins for error-free repair but no error-prone translesion DNA polymerases, which may suggest that absence of mutagenic lesion bypass is crucial for error-free repair of massive DNA damage. However, many other radiation-resistant Deinococcus species do possess translesion polymerases, and radiation-induced mutagenesis has been demonstrated. At least dozens of Deinococcus species contain a mutagenesis cassette, and some even two cassettes, encoding error-prone translesion polymerase DnaE2 and two other proteins, ImuY and ImuB-C, that are probable accessory factors required for DnaE2 activity. Expression of this mutagenesis cassette is under control of the SOS regulators RecA and LexA. In this paper, we review both the RecA/LexA-controlled mutagenesis and the IrrE/DdrO-controlled radiation/desiccation response in Deinococcus. | 2021 | 33923690 |
| 6732 | 17 | 0.9859 | Assessment of Bioavailability of Biochar-Sorbed Tetracycline to Escherichia coli for Activation of Antibiotic Resistance Genes. Human overuse and misuse of antibiotics have caused the wide dissemination of antibiotics in the environment, which has promoted the development and proliferation of antibiotic resistance genes (ARGs) in soils. Biochar (BC) with strong sorption affinity to many antibiotics is considered to sequester antibiotics and hence mitigate their impacts to bacterial communities in soils. However, little is known about whether BC-sorbed antibiotics are bioavailable and exert selective pressure on soil bacteria. In this study, we probed the bioavailability of tetracycline sorbed by BCs prepared from rice-, wheat-, maize-, and bean-straw feedstock using Escherichia coli MC4100/pTGM bioreporter strain. The results revealed that BC-sorbed tetracycline was still bioavailable to the E. coli attached to BC surfaces. Tetracycline sorbed by BCs prepared at 400 °C (BC400) demonstrated a higher bioavailability to bacteria compared to that sorbed by BCs prepared at 500 °C (BC500). Tetracycline could be sorbed primarily in the small pores of BC500 where bacteria could not access due to the size exclusion to bacteria. In contrast, tetracycline could be sorbed mainly on BC400 surfaces where bacteria could conveniently access tetracycline. Increasing the ambient humidity apparently enhanced the bioavailability of BC400-sorbed tetracycline. BC500-sorbed tetracycline exposed to varying levels of ambient humidity showed no significant changes in bioavailability, indicating that water could not effectively mobilize tetracycline from BC500 pores to surfaces where bacteria could access tetracycline. The results from this study suggest that BCs prepared at a higher pyrolysis temperature could be more effective to sequester tetracycline and mitigate the selective pressure on soil bacteria. | 2020 | 32786566 |
| 8657 | 18 | 0.9858 | The Phytoplankton Taxon-Dependent Oil Response and Its Microbiome: Correlation but Not Causation. Phytoplankton strongly interact with their associated bacteria, both attached (PA), and free-living (FL), and bacterial community structures can be specific to phytoplankton species. Similarly, responses to environmental stressors can vary by taxon, as exemplified by observed shifts in phytoplankton community structure from diatoms to phytoflagellates after the Deepwater Horizon (DWH) oil spill. Here, we assess the extent to which associated bacteria influence the phytoplankton taxon-specific oil response by exposing xenic and axenic strains of three phytoplankton species to oil and/or dispersant. The dinoflagellates Amphidinium carterae and Peridinium sociale, and the diatom Skeletonema sp., all harbored significantly distinct bacterial communities that reflected their host oil response. Oil degrading bacteria were detected in both PA and FL communities of the oil resistant dinoflagellates, but their FL bacteria were more efficient in lipid hydrolysis, a proxy for oil degradation capability. Inversely, the growth rate and photosynthetic parameters of the diatom Skeletonema sp. was the most impacted by dispersed oil compared to the dinoflagellates, and oil-degrading bacteria were not significantly associated to its microbiome, even in the dispersed oil treatment. Moreover, the FL bacteria of Skeletonema did not show significant oil degradation. Yet, the lack of consistent significant differences in growth or photosynthetic parameters between the xenic and axenic cultures after oil exposure suggest that, physiologically, the associated bacteria do not modify the phytoplankton oil response. Instead, both oil resistance and phycosphere composition appear to be species-specific characteristics that are not causally linked. This study explores one aspect of what is undoubtedly a complex suite of interactions between phytoplankton and their associated bacteria; future analyses would benefit from studies of genes and metabolites that mediate algal-bacterial exchanges. | 2019 | 30915045 |
| 6733 | 19 | 0.9858 | Bioavailability of tetracycline to antibiotic resistant Escherichia coli in water-clay systems. Tetracyclines are a class of antimicrobials frequently found in the environment, and have promoted the proliferation of antibiotic resistance. An unanswered research question is whether tetracycline sorbed to soils is still bioavailable to bacteria and exerts selective pressure on the bacterial community for the development of antibiotic resistance. In this study, bioreporter E. coli MC4100/pTGM strain was used to probe the bioavailability of tetracycline sorbed by smectite clay, a class of common soil minerals. Batch sorption experiments were conducted to prepare clay samples with a wide range of sorbed tetracycline concentration. The bioreporter was incubated with tetracycline-sorbed clay at different clay/solution ratios and water contents, as well as using dialysis tubings to prevent the direct contact between bacterial cells and clay particles. The expression of antibiotic resistance genes from the bioreporter was measured using a flow cytometer as a measurement of bioavailability/selective pressure. The direct contact of bioreporter cells to clay surfaces represented an important pathway facilitating bacterial access to clay-sorbed tetracycline. In clay-water suspensions, reducing solution volume rendered more bacteria to attach to clay surfaces enhancing the bioavailability of clay-sorbed tetracycline. The strong fluorescence emission from bioreporter cells on clay surfaces indicated that clay-sorbed tetracycline was still bioavailable to bacteria. The formation of biofilms on clay surfaces could increase bacterial access to clay-sorbed tetracycline. In addition, desorption of loosely sorbed tetracycline into bulk solution contributed to bacterial exposure and activation of the antibiotic resistance genes. Tetracycline sorbed by soil geosorbents could exert selective pressure on the surrounding microbial communities via bacterial exposure to tetracycline in solution from desorption and to the geosorbent-sorbed tetracycline as well. | 2018 | 30253298 |