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Sun C, Mao C, Zhou Z, Xiao J, Zhou W, Du J, Li J. In Vitro Assessment of Ozone-Treated Deoxynivalenol by Measuring Cytotoxicity and Wheat Quality. Toxins (Basel) 2024; 16:64. [PMID: 38393142 PMCID: PMC10893320 DOI: 10.3390/toxins16020064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 02/25/2024] Open
Abstract
Deoxynivalenol (DON), a trichothecene mycotoxin, could lead to cytotoxicity in both animal bodies and plant seed cells. Ozone degradation technology has been applied to DON control. However, the safety and quality of the contaminated grain after DON degradation are largely obscured. In this work, we evaluated the cytotoxicity of ozone-treated DON through seed germination experiments and cytotoxicity tests. Cell experiments showed that the inhibition rate of HepG2 viability gradually increased within the concentrations of 1-10 mg/L of DON, alongside which an IC50 (half maximal inhibitory concentration) of 9.1 mg/L was determined. In contrast, degrading DON had no significant inhibitory effect on cell growth. Moreover, a 1-10 mg/L concentration of DON increased production of a large amount of reactive oxygen radicals in HepG2, with obvious fluorescence color development. However, fluorescence intensity decreased after DON degradation. Further, DON at a concentration of >1 mg/L significantly inhibited the germination of mung bean seeds, whereas no significant inhibition of their germination or growth were observed if DON degraded. Changes in total protein content, fatty acid value, and starch content were insignificant in wheat samples suffering ozone degradation, compared to the untreated group. Lastly, the ozone-treated wheat samples exhibited higher tenacity and whiteness. Together, our study indicated that the toxicity of DON-contaminated wheat was significantly reduced after ozone degradation.
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Affiliation(s)
- Chao Sun
- College of Food Science and Engineering, Jiangxi Agricultural University, Zhimin Avenue, No. 1011, Nanchang 330045, China; (C.S.); (W.Z.)
| | - Chuncai Mao
- Jiangxi Enterprise Technology Center, Huangshanghuang Group Food Co., Ltd., Xiaolanzhong Avenue, No. 66, Nanchang 330052, China
| | - Zhie Zhou
- College of Food Science and Engineering, Jiangxi Agricultural University, Zhimin Avenue, No. 1011, Nanchang 330045, China; (C.S.); (W.Z.)
| | - Jianhui Xiao
- College of Food Science and Engineering, Jiangxi Agricultural University, Zhimin Avenue, No. 1011, Nanchang 330045, China; (C.S.); (W.Z.)
| | - Wenwen Zhou
- College of Food Science and Engineering, Jiangxi Agricultural University, Zhimin Avenue, No. 1011, Nanchang 330045, China; (C.S.); (W.Z.)
| | - Juan Du
- College of Food Science and Engineering, Jiangxi Agricultural University, Zhimin Avenue, No. 1011, Nanchang 330045, China; (C.S.); (W.Z.)
| | - Jun Li
- College of Food Science and Engineering, Jiangxi Agricultural University, Zhimin Avenue, No. 1011, Nanchang 330045, China; (C.S.); (W.Z.)
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Navarro-Monserrat ED, Taylor CG. T6SS: A Key to Pseudomonas's Success in Biocontrol? Microorganisms 2023; 11:2718. [PMID: 38004732 PMCID: PMC10673566 DOI: 10.3390/microorganisms11112718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/29/2023] [Accepted: 10/30/2023] [Indexed: 11/26/2023] Open
Abstract
Bacteria from the genus Pseudomonas have been extensively studied for their capacity to act as biological control agents of disease and pests and for their ability to enhance and promote crop production in agricultural systems. While initial research primarily focused on the human pathogenic bacteria Pseudomonas aeruginosa, recent studies indicate the significance of type VI secretion (T6SS) in other Pseudomonas strains for biocontrol purposes. This system possibly plays a pivotal role in restricting the biological activity of target microorganisms and may also contribute to the bolstering of the survival capabilities of the bacteria within their applied environment. The type VI secretion system is a phage-like structure used to translocate effectors into both prokaryotic and eukaryotic target cells. T6SSs are involved in a myriad of interactions, some of which have direct implications in the success of Pseudomonas as biocontrol agents. The prevalence of T6SSs in the genomes of Pseudomonas species is notably greater than the estimated 25% occurrence rate found in Gram-negative bacteria. This observation implies that T6SS likely plays a pivotal role in the survival and fitness of Pseudomonas. This review provides a brief overview of T6SS, its role in Pseudomonas with biocontrol applications, and future avenues of research within this subject matter.
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Affiliation(s)
| | - Christopher G. Taylor
- Department of Plant Pathology, Ohio Agricultural Research and Development Center, Wooster, OH 44691, USA;
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Pseudomonas aeruginosa H3-T6SS Combats H 2O 2 Stress by Diminishing the Amount of Intracellular Unincorporated Iron in a Dps-Dependent Manner and Inhibiting the Synthesis of PQS. Int J Mol Sci 2023; 24:ijms24021614. [PMID: 36675127 PMCID: PMC9866239 DOI: 10.3390/ijms24021614] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/28/2022] [Accepted: 01/10/2023] [Indexed: 01/17/2023] Open
Abstract
The type VI secretion system (T6SS), a protein translocation nanomachine, is widely distributed in Gram-negative bacteria and delivers effectors directly into target cells or the extracellular environment to help the bacteria gain a competitive fitness advantage and promote bacterial survival in harmful environments. In this study, we demonstrated that the synthesis of the Pseudomonas quinolone signal (PQS) in Pseudomonas aeruginosa PAO1 was inhibited by the H3-T6SS gene cluster under iron-rich conditions, and that this inhibition was relieved under iron starvation conditions. Conversely, PQS differentially regulated the expression of the H3-T6SS structural genes and the effector protein gene tseF. The expression of tseF was inhibited by PQS, while the expressions of the H3-T6SS structural genes were positively regulated by PQS. Further studies showed that the H3-T6SS was involved in the resistance of P. aeruginosa to oxidative stress caused by hydrogen peroxide (H2O2). Interestingly, H3-T6SS expression was neither induced by H2O2 stress nor regulated by OxyR (a global anti-oxidative transcriptional regulator) but was positively regulated by RpoS (a major transcription regulator of the stress response). In addition, we found that the clpV3 (a structural gene of H3-T6SS) mutation resulted in upregulation of two proteins related to PQS synthesis and many proteins related to oxidative stress resistance, while the expression of some iron storage proteins, especially Dps, were significantly downregulated. Furthermore, the clpV3 mutation led to an increase in the intracellular free Fe2+ content of P. aeruginosa. Further studies showed that both the PQS deficient mutation and overexpression of dps effectively restored the H2O2 sensitive phenotype of the H3-T6SS mutant. Finally, we proposed the following model of H3-T6SS-mediated resistance to H2O2 stress in P. aeruginosa. H3-T6SS not only reduces the intracellular free Fe2+ level by upregulating the expression of ferritin Dps, but also inhibits the synthesis of PQS to mediate the resistance of P. aeruginosa to H2O2 stress. This study highlights the important role of H3-T6SS in the ability of P. aeruginosa to combat H2O2 stress and provides a perspective for understanding the stress response mechanism of bacteria.
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Ma X, Liu Q, Song F, Huang Y. Differentially Expressed Genes of Pseudomonas aeruginosa Isolates from Eyes with Keratitis and Healthy Conjunctival Sacs. Infect Drug Resist 2022; 15:4495-4506. [PMID: 35983295 PMCID: PMC9380828 DOI: 10.2147/idr.s374335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 08/06/2022] [Indexed: 11/23/2022] Open
Abstract
Background Pseudomonas aeruginosa (P. aeruginosa) is the second-most common commensal bacterium in healthy conjunctival sacs. When the corneal epithelial barrier is damaged, P. aeruginosa in a healthy conjunctival sac can cause infectious keratitis, which can result in the loss of vision. This study was designed to investigate the differentially expressed genes (DEGs) of P. aeruginosa isolates from eyes with keratitis and from healthy conjunctival sacs to predict their functions and pathways through Illumina high-throughput RNA sequencing (RNA-seq). Methods P. aeruginosa isolates from keratitis and healthy conjunctival sacs were obtained. The transcriptome profile of P. aeruginosa was characterized by a high throughput RNA-seq strategy using the Illumina HiSeq 2500 platform. The DEGs were analyzed with DESeq and validated through quantitative real-time polymerase chain reaction (PCR) and with experimental mice. GO enrichment and the KEGG pathway were also analyzed. Results In genome-wide transcriptional analysis, 557 genes (332 upregulated and 225 downregulated) were found to be differentially expressed (fold change ≥ 2, p ≤ 0.05) in the strains from keratitis. GO enrichment analysis suggested that DEGs tended to be associated with cellular and metabolic processes. KEGG pathway analysis revealed the DEGs were typically associated with the pathways of the bacterial secretion system and pyoverdine metabolism. Eleven DEGs were validated using quantitative reverse-transcription PCR and verified with experimental mice. The results were consistent with those obtained in RNA-seq. Conclusion The DEGs related to pilin, T2SS, T3SS, and pyoverdine metabolisms were significantly altered in the strains from keratitis. The findings may be helpful for further investigations on genes or pathways related to the pathogenesis of and therapeutic targets for P. aeruginosa keratitis.
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Affiliation(s)
- Xiubin Ma
- Department of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, People's Republic of China.,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Qingdao, People's Republic of China.,Department of Ophthalmology, School of Ophthalmology, Shandong First Medical University, Qingdao, People's Republic of China
| | - Qing Liu
- Department of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, People's Republic of China.,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Qingdao, People's Republic of China.,Department of Ophthalmology, School of Ophthalmology, Shandong First Medical University, Qingdao, People's Republic of China
| | - Fangying Song
- Department of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, People's Republic of China.,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Qingdao, People's Republic of China.,Department of Ophthalmology, School of Ophthalmology, Shandong First Medical University, Qingdao, People's Republic of China
| | - Yusen Huang
- Department of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, People's Republic of China.,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Qingdao, People's Republic of China.,Department of Ophthalmology, School of Ophthalmology, Shandong First Medical University, Qingdao, People's Republic of China
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Lin J, Xu L, Yang J, Wang Z, Shen X. Beyond dueling: roles of the type VI secretion system in microbiome modulation, pathogenesis and stress resistance. STRESS BIOLOGY 2021; 1:11. [PMID: 37676535 PMCID: PMC10441901 DOI: 10.1007/s44154-021-00008-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 08/09/2021] [Indexed: 09/08/2023]
Abstract
Bacteria inhabit diverse and dynamic environments, where nutrients may be limited and toxic chemicals can be prevalent. To adapt to these stressful conditions, bacteria have evolved specialized protein secretion systems, such as the type VI secretion system (T6SS) to facilitate their survival. As a molecular syringe, the T6SS expels various effectors into neighboring bacterial cells, eukaryotic cells, or the extracellular environment. These effectors improve the competitive fitness and environmental adaption of bacterial cells. Although primarily recognized as antibacterial weapons, recent studies have demonstrated that T6SSs have functions beyond interspecies competition. Here, we summarize recent research on the role of T6SSs in microbiome modulation, pathogenesis, and stress resistance.
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Affiliation(s)
- Jinshui Lin
- Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, People's Republic of China
| | - Lei Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Jianshe Yang
- Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, People's Republic of China
| | - Zhuo Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
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Xie L, Zhou A, Zhao J, Tang Y, Zhao R, Zhou Y, Cao G, Zhong C, Li J. Comparative insights into multiple drug resistance determinants in Stenotrophomonas maltophilia MER1. J Glob Antimicrob Resist 2021; 27:20-25. [PMID: 34365056 DOI: 10.1016/j.jgar.2021.07.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 07/19/2021] [Accepted: 07/22/2021] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES Multidrug-resistant (MDR) Stenotrophomonas maltophilia strain MER1 was isolated from hospital wastewater in Shandong Province, China. This study aimed to determine the genetic determinants related to its striking MDR phenotype. METHODS Antimicrobial susceptibility testing of strain MER1 was performed by disk diffusion on Mueller-Hinton agar plates, and MICs were interpreted according to Clinical and Laboratory Standards Institute breakpoints. The genome of MER1 was sequenced and assembled using PacBio RS II and BGISEQ-500 platforms. Antimicrobial resistance determinants together with other transferability or adaptability determinants were identified by comparative genomics. Phylogenetic and contextual assays for these elements were conducted to assess the risk of spread of MER1. RESULTS Antimicrobial susceptibility testing revealed that strain MER1 is resistant to nine different antibiotics, including ampicillin, meropenem, amikacin, erythromycin, vancomycin, tetracycline, tigecycline, colistin and ceftazidime. Several genes were identified encoding efflux pumps and drug-inactivating agents, accounting for resistance to the above antibiotics, including meropenem, tigecycline and colistin regarded as last-line therapies for infections caused by MDR Gram-negative bacteria. MER1 co-harbours two non-mobile mcr homologues. A novel genomic region of variability was demonstrated to confer bacterial robustness and adaptability upon strain MER1. CONCLUSION Collective efforts revealed the MDR properties and potential genetic determinants of S. maltophilia MER1 isolated from hospital wastewater. Comparative genomic analysis of S. maltophilia MER1 may provide insights into the prevention and treatment of antimicrobial-resistant infections. Our findings raise concern that the MDR genes in the reservoir of S. maltophilia may further spread into various ecological niches or medically high-risk pathogens.
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Affiliation(s)
- Linlin Xie
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China; Jiangxi Key Laboratory of Natural Product and Functional Food, College of Food Science and Engineering, Jiangxi Agricultural University, Nanchang, China
| | - Aiping Zhou
- Department of Laboratory Medicine, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Jia Zhao
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, China
| | - Yuhang Tang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Rui Zhao
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Yingping Zhou
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, China
| | - Guangxiang Cao
- College of Biomedical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Chuanqing Zhong
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, China.
| | - Jun Li
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China; Jiangxi Key Laboratory of Natural Product and Functional Food, College of Food Science and Engineering, Jiangxi Agricultural University, Nanchang, China.
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