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Shi H, He F, Huo C, Wan J, Song H, Du F, Liu R. Molecular mechanisms of polystyrene nanoplastics and alpha-amylase interactions and their binding model: A multidimensional analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 915:170036. [PMID: 38242479 DOI: 10.1016/j.scitotenv.2024.170036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/06/2024] [Accepted: 01/07/2024] [Indexed: 01/21/2024]
Abstract
Plastic fragments are widely distributed in different environmental media and has recently drawn special attention due to its difficulty in degradation and serious health and environmental problems. Among, nanoplastics (NPs) are smaller in size, larger in surface/volume ratio, and more likely to easily adsorb ambient pollutants than macro plastic particles. Moreover, NPs can be easily absorbed by wide variety of organisms and accumulate in multiple tissues/organs and cells, thus posing a more serious threat to living organisms. Alpha-amylase (α-amylase) is a hydrolase, which can be derived from various sources such as animals, plants, and microorganisms. Currently, no studies have concentrated on the binding of NPs with α-amylase and their interaction mechanisms by employing a multidimensional strategy. Hence, we explored the interaction mechanisms of polystyrene nanoplastics (PS-NPs) with α-amylase by means of multispectral analysis, in vitro enzymatic activity analysis, and molecular simulation techniques under in vitro conditions. The findings showed that PS-NPs had the capability to bind with the intrinsic fluorescence chromophores, leading to fluorescence changes of these specific amino acids. This interaction also caused the alterations in the micro-environment of the fluorophore residues mainly tryptophan (TRP) and tyrosine (TYR) residues of α-amylase. PS-NPs interaction promoted the unfolding and partial expansion of polypeptide chains and the loosening of protein skeletons, and destroyed the secondary structure (increased random coil contents and decreased α-helical contents) of this protein, forming a larger particle size of the PS-NPs-α-amylase complex. Moreover, the enzymatic activity of α-amylase in vitro was found to be inhibited in a concentration dependent manner, thereby impairing its physiological functions. Further molecular simulation found that PS-NPs had a higher tendency to bind to the active site of α-amylase, which is the cause for its structural and functional changes. Additionally, the hydrophobic force played a major role in mediating the binding interactions between PS-NPs and α-amylase. Taken together, our study indicated that PS-NPs interaction can initiate the abnormal physiological functions of α-amylase through PS-NPs-induced structural and conformational alternations.
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Affiliation(s)
- Huijian Shi
- School of Environmental Science and Engineering, Shandong University, China-America CRC for Environment & Health, Shandong Province, 72# Jimo Binhai Road, Qingdao, Shandong 266237, PR China
| | - Falin He
- School of Environmental Science and Engineering, Shandong University, China-America CRC for Environment & Health, Shandong Province, 72# Jimo Binhai Road, Qingdao, Shandong 266237, PR China
| | - Chengqian Huo
- School of Environmental Science and Engineering, Shandong University, China-America CRC for Environment & Health, Shandong Province, 72# Jimo Binhai Road, Qingdao, Shandong 266237, PR China
| | - Jingqiang Wan
- School of Environmental Science and Engineering, Shandong University, China-America CRC for Environment & Health, Shandong Province, 72# Jimo Binhai Road, Qingdao, Shandong 266237, PR China
| | - Hengyu Song
- School of Environmental Science and Engineering, Shandong University, China-America CRC for Environment & Health, Shandong Province, 72# Jimo Binhai Road, Qingdao, Shandong 266237, PR China
| | - Fei Du
- School of Environmental Science and Engineering, Shandong University, China-America CRC for Environment & Health, Shandong Province, 72# Jimo Binhai Road, Qingdao, Shandong 266237, PR China
| | - Rutao Liu
- School of Environmental Science and Engineering, Shandong University, China-America CRC for Environment & Health, Shandong Province, 72# Jimo Binhai Road, Qingdao, Shandong 266237, PR China.
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Zhang Y, Qin K, Liu C. Low-density polyethylene enhances the disturbance of microbiome and antibiotic resistance genes transfer in soil-earthworm system induced by pyraclostrobin. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133459. [PMID: 38219581 DOI: 10.1016/j.jhazmat.2024.133459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/03/2024] [Accepted: 01/04/2024] [Indexed: 01/16/2024]
Abstract
Non-antibiotic chemicals in farmlands, including microplastics (MPs) and pesticides, have the potential to influence the soil microbiome and the dissemination of antibiotic resistance genes (ARGs). Despite this, there is limited understanding of the combined effects of MPs and pesticides on microbial communities and ARGs transmission in soil ecosystems. In this study, we observed that low-density polyethylene (LDPE) microplastic enhance the accumulation of pyraclostrobin in earthworms, resulting in reduced weight and causing severe oxidative damage. Analysis of 16 S rRNA amplification revealed that exposure to pyraclostrobin and/or LDPE disrupts the microbial community structure at the phylum and genus levels, leading to reduced alpha diversity in both the soil and earthworm gut. Furthermore, co-exposure to LDPE and pyraclostrobin increased the relative abundance of ARGs in the soil and earthworm gut by 2.15 and 1.34 times, respectively, compared to exposure to pyraclostrobin alone. It correlated well with the increasing relative abundance of genera carrying ARGs. Our findings contribute novel insights into the impact of co-exposure to MPs and pesticides on soil and earthworm microbiomes, highlighting their role in promoting the transfer of ARGs. This knowledge is crucial for managing the risk associated with the dissemination of ARGs in soil ecosystems.
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Affiliation(s)
- Yirong Zhang
- National Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Wushan Road 483, Tianhe District, Guangzhou 510642, China
| | - Kaikai Qin
- National Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Wushan Road 483, Tianhe District, Guangzhou 510642, China
| | - Chenglan Liu
- National Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Wushan Road 483, Tianhe District, Guangzhou 510642, China.
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