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Li C, Liu Q, Wang Y, Yang X, Chen S, Zhao Y, Wu Y, Li L. Salt stress improves thermotolerance and high-temperature bioethanol production of multi-stress-tolerant Pichia kudriavzevii by stimulating intracellular metabolism and inhibiting oxidative damage. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:222. [PMID: 34823567 PMCID: PMC8613974 DOI: 10.1186/s13068-021-02071-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 11/10/2021] [Indexed: 05/29/2023]
Abstract
BACKGROUND High-temperature bioethanol production benefits from yeast thermotolerance. Salt stress could induce obvious cross-protection against heat stress of Pichia kudriavzevii, contributing to the improvement of its thermotolerance and bioethanol fermentation. However, the underlying mechanisms of the cross-protection remain poorly understood. RESULTS Salt stress showed obvious cross-protection for thermotolerance and high-temperature ethanol production of P. kudriavzevii observed by biomass, cell morphology and bioethanol production capacity. The biomass and ethanol production of P. kudriavzevii at 45 °C were, respectively, improved by 2.6 and 3.9 times by 300 mmol/L NaCl. Metabolic network map showed that salt stress obviously improved the key enzymes and intermediates in carbohydrate metabolism, contributing to the synthesis of bioethanol, ATP, amino acids, nucleotides, and unsaturated fatty acids, as well as subsequent intracellular metabolisms. The increasing trehalose, glycerol, HSPs, and ergosterol helped maintain the normal function of cell components. Heat stress induced serious oxidative stress that the ROS-positive cell rate and dead cell rate, respectively, rose from 0.5% and 2.4% to 28.2% and 69.2%, with the incubation temperature increasing from 30 to 45 °C. The heat-induced ROS outburst, oxidative damage, and cell death were obviously inhibited by salt stress, especially the dead cell rate which fell to only 20.3% at 300 mmol/L NaCl. The inhibiting oxidative damage mainly resulted from the abundant synthesis of GSH and GST, which, respectively, increased by 4.8 and 76.1 times after addition of 300 mmol/L NaCl. The improved bioethanol production was not only due to the improved thermotolerance, but resulted from the up-regulated alcohol dehydrogenases and down-regulated aldehyde dehydrogenases by salt stress. CONCLUSION The results provide a first insight into the mechanisms of the improved thermotolerance and high-temperature bioethanol production of P. kudriavzevii by salt stress, and provide important information to construct genetic engineering yeasts for high-temperature bioethanol production.
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Affiliation(s)
- Chunsheng Li
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, China
- Co-Innovation Center of Jiangsu Marine Bio-Industry Technology, Jiangsu Ocean University, Lianyungang, 222005, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, 116034, China
| | - Qiuying Liu
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, China
| | - Yueqi Wang
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, China
- Co-Innovation Center of Jiangsu Marine Bio-Industry Technology, Jiangsu Ocean University, Lianyungang, 222005, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, 116034, China
| | - Xianqing Yang
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, China.
| | - Shengjun Chen
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, China
| | - Yongqiang Zhao
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, China
- Co-Innovation Center of Jiangsu Marine Bio-Industry Technology, Jiangsu Ocean University, Lianyungang, 222005, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, 116034, China
| | - Yanyan Wu
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, China
| | - Laihao Li
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, China
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Ma N, Cai R, Sun C. Threonine dehydratase enhances bacterial cadmium resistance via driving cysteine desulfuration and biomineralization of cadmium sulfide nanocrystals. JOURNAL OF HAZARDOUS MATERIALS 2021; 417:126102. [PMID: 34015711 DOI: 10.1016/j.jhazmat.2021.126102] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 05/09/2021] [Accepted: 05/10/2021] [Indexed: 06/12/2023]
Abstract
Biomineralization is often used by microorganisms to sequester heavy metal ions and provides a potential means for remediating increasing levels of heavy metal pollution. Bacteria have been shown to utilize cysteine for the biomineralization of metal sulfide. Indeed, in the present study, the supplement of L-cysteine was found to significantly improve both cadmium resistance and removal abilities of a deep-sea bacterium Pseudomonas stutzeri 273 through cadmium sulfide (CdS) nanoparticle biomineralization. With a proteomic approach, threonine dehydratase of P. stutzeri 273 (psTD) was proposed to be a key factor enhancing bacterial cadmium resistance through catalyzing L-cysteine desulfuration, H2S generation and CdS nanoparticle biomineralization. Consistently, deletion of the gene encoding psTD in P. stutzeri 273 resulted in the decline of H2S generation, decrease of cadmium resistance, and reduction of cadmium removal ability, confirming the unique function of psTD directing the formation of CdS nanoparticles. Correspondingly, the single-enzyme biomineralization of CdS nanoparticle driven by psTD was further developed, and psTD was shown to act as a capping reagent for the mineralization reaction, which controlling the size and structure of nanocrystals. Our results provide important clues for the construction of engineered bacteria for cadmium bioremediation and widen the synthesis methods of nanomaterials.
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Affiliation(s)
- Ning Ma
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; College of Earth Science, University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Ruining Cai
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; College of Earth Science, University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Chaomin Sun
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
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Ma N, Sun C. Cadmium sulfide nanoparticle biomineralization and biofilm formation mediate cadmium resistance of the deep-sea bacterium Pseudoalteromonas sp. MT33b. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:325-336. [PMID: 33511774 DOI: 10.1111/1758-2229.12933] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 01/21/2021] [Accepted: 01/24/2021] [Indexed: 06/12/2023]
Abstract
Cadmium (Cd) is a common toxic heavy metal in the environment, and bacteria have evolved different strategies to deal with Cd toxicity. Here, a bacterium designated Pseudoalteromonas sp. MT33b possessing strong Cd resistance was isolated from the Mariana Trench sediments. Supplement of cysteine significantly increased bacterial Cd resistance and removal rate. Biofilm formation was demonstrated to play a positive role toward bacterial Cd resistance. Transcriptome analysis showed the supplement of cysteine effectively prevented Cd2+ from entering bacterial cells, promoted saccharide metabolism and thereby facilitating energy production, which consists well with bacterial growth trend analysed under the same conditions. Notably, the expressions of many biofilm formation related genes including flagellar assembly, signal transduction, bacterial secretion and TonB-dependent transfer system were significantly upregulated when facing Cd stress, indicating their important roles in determining bacterial biofilm formation and enhancing Cd resistance. Overall, this study indicates the formation of insoluble CdS precipitates and massive biofilm is the major strategy adopted by Pseudoalteromonas sp. MT33b to eliminate Cd stress. Our results provide a good model to investigate how heavy metals impact biofilm formation in the deep-sea ecosystems, which may facilitate a deeper understanding of microbial environmental adaptability and better utilization of these microbes for bioremediation purposes in the future.
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Affiliation(s)
- Ning Ma
- CAS Key Laboratory of Experimental Marine Biology & Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
- College of Earth Science, University of Chinese Academy of Sciences, Beijing, 100049, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Chaomin Sun
- CAS Key Laboratory of Experimental Marine Biology & Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China
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Chen Y, Feng J, Liu J, Zhou H, Luo H, Xue C, Gao W. Effects of neutron radiation on Nrf2-regulated antioxidant defense systems in rat lens. Exp Ther Med 2021; 21:334. [PMID: 33732307 PMCID: PMC7903385 DOI: 10.3892/etm.2021.9765] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 01/08/2021] [Indexed: 12/20/2022] Open
Abstract
Accumulating evidence suggests that ionizing radiation (IR)-induced cataract may be associated with oxidative stress. Nuclear factor erythroid 2-related factor 2 (Nrf2) serves as a master regulator of the antioxidant defense system against oxidative stress. The present study aimed to investigate the effects of different doses of neutron radiation on the Nrf2-reegulated antioxidant defense system in rat lens and assess the status of oxidative stress. A total of 24 SD rats were randomly divided into the following four groups: i) Control group; iis) 0.4 Sv group; iii) 1.2 Sv group; and iv) 3.6 Sv group. The rats were sacrificed 7 days after radiation and lenses were dissected for histological, biochemical (malondialdehyde, glutathione and superoxide dismutase) and western blot (Nrf2, glutamate-cysteine ligase catalytic subunit and heme oxygenase 1) analyses. The morphological features of the lenses remained intact in the 0.4 Sv, 1.2 Sv and control groups, whilst the lenses in the 3.6 Sv group exhibited injuries. Results from the TUNEL assay demonstrated apparent apoptosis in lens epithelial cells following 3.6 Sv neutron radiation whereas sparse apoptosis was observed following 0.4 Sv and 1.2 Sv radiation. Malondialdehyde levels were reduced in the 0.4 Sv and 1.2 Sv groups but increased in the 3.6 Sv group, compared with those in the control group. Conversely, glutathione expression and the activity of superoxide dismutase were higher in the 0.4 Sv and 1.2 Sv groups, but lower in the 3.6 Sv group, compared with those in the control group. In addition, the total and nuclear protein levels of Nrf2 were increased following neutron radiation compared with those in the control group, though the Nrf2 protein levels decreased in the 3.6 Sv group compared with those in the 1.2 Sv group. The levels of glutamate-cysteine ligase catalytic subunit and heme oxygenase 1, downstream antioxidant enzymes of Nrf2, demonstrated the same profile as that in Nrf2. Taken together, the results of the present study suggest that neutron radiation affects Nrf2-regulated antioxidant systems in a two-stage process. Namely, the induction phase for low-dose radiation and regression phase for high-dose radiation. Therefore, it was hypothesized that activation and enhancement of the Nrf2-regulated antioxidant system may be useful in preventing or delaying IR-induced cataract, which may be extended even for other diseases associated with oxidative stress.
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Affiliation(s)
- Yueqin Chen
- Department of Ophthalmology, The Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210029, P.R. China.,Department of Ophthalmology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, P.R. China
| | - Jundong Feng
- Key Laboratory of Nuclear Technology Application and Radiation Protection in Astronautics (Nanjing University of Aeronautics and Astronautics), Ministry of Industry and Information Technology, Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016, P.R. China
| | - Jingyu Liu
- Department of Ophthalmology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, P.R. China
| | - Hao Zhou
- Key Laboratory of Nuclear Technology Application and Radiation Protection in Astronautics (Nanjing University of Aeronautics and Astronautics), Ministry of Industry and Information Technology, Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016, P.R. China
| | - Huiyao Luo
- Key Laboratory of Nuclear Technology Application and Radiation Protection in Astronautics (Nanjing University of Aeronautics and Astronautics), Ministry of Industry and Information Technology, Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016, P.R. China
| | - Chunyan Xue
- Department of Ophthalmology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, P.R. China
| | - Weiping Gao
- Department of Ophthalmology, The Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210029, P.R. China
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Abstract
Aluminum ions are toxic to bacteria and are thus frequently used for preservation in the food industry. However, at higher concentrations, aluminum is toxic to animals. The extraction of aluminum from aluminum-contaminated foods would therefore be beneficial. Based on the discovery of yeast strains that can tolerate and absorb toxic metals, we aimed to identify strains that could tolerate and absorb aluminum. In this study, yeast were isolated from soil samples and cultured in medium containing the toxic concentration of aluminum chloride (5 mM) for Saccharomyces cerevisiae BY4741. Among aluminum-tolerant strains, two strains, Alt-OF2 and Alt-OF5, were identified as aluminum-absorbing. D1/D2 sequencing revealed that both strains belonged to the genus Schizoblastosporion (syn. Nadsonia).
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Affiliation(s)
- Kosuke Kakita
- Department of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | - Masao Kishida
- Department of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University.,Research Center of Microorganism Control, Osaka Prefecture University
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Ma N, Sha Z, Sun C. Formation of cadmium sulfide nanoparticles mediates cadmium resistance and light utilization of the deep-sea bacterium Idiomarina sp. OT37-5b. Environ Microbiol 2020; 23:934-948. [PMID: 32815245 DOI: 10.1111/1462-2920.15205] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/16/2020] [Indexed: 01/10/2023]
Abstract
Heavy metal is one of the major factors threatening the survival of microorganisms. Here, a deep-sea bacterium designated Idiomarina sp. OT37-5b possessing strong cadmium (Cd) tolerance was isolated from a typical hydrothermal vent. Both the Cd-resistance and removal efficiency of Idiomarina sp. OT37-5b were significantly promoted by the supplement of cysteine and meanwhile large amount of CdS nanoparticles were observed. Production of H2 S from cysteine catalysed by methionine gamma-lyase was further demonstrated to contribute to the formation of CdS nanoparticles. Proteomic results showed the addition of cysteine effectively enhanced the efflux of Cd, improved the activities of reactive oxygen species scavenging enzymes, and thereby boosted the nitrogen reduction and energy production of Idiomarina sp. OT37-5b. Notably, the existence of CdS nanoparticles obviously promoted the growth of Idiomarina sp. OT37-5b when exposed to light, indicating this bacterium might grab light energy through CdS nanoparticles. Proteomic analysis revealed the expression levels of essential components for light utilization including electron transport, cytochrome complex and F-type ATPase were significantly up-regulated, which strongly suggested the formation of CdS nanoparticles promoted light utilization and energy production. Our results provide a good model to investigate the uncovered mechanisms of self-photosensitization of nonphotosynthetic bacteria for light-to-chemical production in the deep biosphere.
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Affiliation(s)
- Ning Ma
- CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.,College of Earth Science, University of Chinese Academy of Sciences, Beijing, 100049, China.,Centre of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Zhongli Sha
- Centre of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.,Laboratory of Marine Organism Taxonomy and Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.,Centre for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Chaomin Sun
- CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.,Centre of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.,Centre for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China
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7
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Ramos-Moreno L, Ramos J, Michán C. Overlapping responses between salt and oxidative stress in Debaryomyces hansenii. World J Microbiol Biotechnol 2019; 35:170. [PMID: 31673816 DOI: 10.1007/s11274-019-2753-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/22/2019] [Indexed: 11/26/2022]
Abstract
Debaryomyces hansenii is a halotolerant yeast of importance in basic and applied research. Previous reports hinted about possible links between saline and oxidative stress responses in this yeast. The aim of this work was to study that hypothesis at different molecular levels, investigating after oxidative and saline stress: (i) transcription of seven genes related to oxidative and/or saline responses, (ii) activity of two main anti-oxidative enzymes, (iii) existence of common metabolic intermediates, and (iv) generation of damages to biomolecules as lipids and proteins. Our results showed how expression of genes related to oxidative stress was induced by exposure to NaCl and KCl, and, vice versa, transcription of some genes related to osmotic/salt stress responses was regulated by H2O2. Moreover, and contrary to S. cerevisiae, in D. hansenii HOG1 and MSN2 genes were modulated by stress at their transcriptional level. At the enzymatic level, saline stress also induced antioxidative enzymatic defenses as catalase and glutathione reductase. Furthermore, we demonstrated that both stresses are connected by the generation of intracellular ROS, and that hydrogen peroxide can affect the accumulation of in-cell sodium. On the other hand, no significant alterations in lipid oxidation or total glutathione content were observed upon exposure to both stresses tested. The results described in this work could help to understand the responses to both stressors, and to improve the biotechnological potential of D. hansenni.
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Affiliation(s)
- Laura Ramos-Moreno
- Departamento de Microbiología, Universidad de Córdoba, Campus de Excelencia Internacional Agroalimentario CeiA3, 14071, Córdoba, España, Spain
| | - José Ramos
- Departamento de Microbiología, Universidad de Córdoba, Campus de Excelencia Internacional Agroalimentario CeiA3, 14071, Córdoba, España, Spain
| | - Carmen Michán
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Campus de Excelencia Internacional Agroalimentario CeiA3, 14071, Córdoba, España, Spain.
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Wang Y, Wang L, Ma C, Wang K, Hao Y, Chen Q, Mo Y, Rui Y. Effects of cerium oxide on rice seedlings as affected by co-exposure of cadmium and salt. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 252:1087-1096. [PMID: 31252106 DOI: 10.1016/j.envpol.2019.06.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 06/02/2019] [Accepted: 06/02/2019] [Indexed: 06/09/2023]
Abstract
Effects of CeO2 NPs (200 mg.L-1) on rice (Oryza sativa L.) alone or co-exposure with cadmium (Cd) and salt (sodium chloride, NaCl) were investigated in hydroponic systems for two weeks. Physiological results show that rice biomass was significantly inhibited when NaCl or CdCl2 added alone or in co-exposure treatment. CeO2 NPs significantly relieve the chlorophyll damage under CdCl2 environmental stress. The presence of CeO2 NPs alleviated both stressors induced damages to rice as indicated by the reduced proline level. Additionally, CeO2 NPs triggered the antioxidant defense systems to counteract the oxidative stress caused by NaCl and CdCl2. The level of 8-OHdG, one of the most important indicators for genotoxicity, in rice suggest that the presence of CeO2 NPs reduced the DNA damage in NaCl treated rice. Elemental analysis indicated that co-exposure to NaCl and CdCl2 slightly decreased the Cd content as compared to the one in the CdCl2 alone treatment, and this co-exposure also significantly reduced the Na content when comparing with the NaCl alone treatment. Taken together, our findings suggest that CeO2 NPs could alleviate the CdCl2 and NaCl stresses, but could not completely change the phenotype of both contaminants treated rice.
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Affiliation(s)
- Yaoyao Wang
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Lingqing Wang
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chuanxin Ma
- Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, New Haven, 06504, CT, United States
| | - Kexiang Wang
- Qingdao Yuance Biotechnology Co, ltd, Qingdao, 266071, China; College of Management, Ocean University of China, Qingdao, 266100, China
| | - Yi Hao
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Qing Chen
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - You Mo
- College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Yukui Rui
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
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Zhang D, Ma N, Guo Z, Chen P, Ma R, Sun X, Wang D, Wang J, Xu Y. Improved cadmium resistance and removal capacity in Pichia kudriavzevii A16 by sucrose preincubation. J Basic Microbiol 2019; 59:867-878. [PMID: 31347180 DOI: 10.1002/jobm.201900272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 06/25/2019] [Accepted: 07/02/2019] [Indexed: 12/18/2022]
Abstract
Removal of heavy metals from food material by growing micro-organisms is limited by the toxicity to cells. In this study, different preincubation treatments were investigated to analyze their effects on cadmium resistance and removal ability of Pichia kudriavzevii A16 and Saccharomyces cerevisiae CICC1211. Sucrose preincubation improved the cadmium resistance of both yeast cells and increased the cadmium-removal rate of P. kudriavzevii A16. An evident decrease of intracellular and cell-surface cadmium accumulation was observed after sucrose preincubation, which may be the primary reason responsible for the improved cadmium resistance. Flow cytometry assay showed that sucrose significantly reduced the production of reactive oxygen species (ROS) and cell death rate of both yeasts under cadmium compared with those normally cultured cells. Under cadmium stress, the content of both protein carbonyls and malonyldialdehyde were also reduced by the addition of sucrose, the results were in accordance with the tendency of ROS, exhibiting a defending function of sucrose. Osmotic regulators as proline and trehalose were increased by sucrose preincubation in P. kudriavzevii A16 in the presence of cadmium. The results suggested that sucrose preincubation could be applied to improve cadmium resistance and removal rate of yeasts.
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Affiliation(s)
- Dandan Zhang
- Laboratory of Food Chemistry and Nutrition, College of Food Science and Engineering, Ocean University of China, Qingdao, China
| | - Ning Ma
- Laboratory of Food Chemistry and Nutrition, College of Food Science and Engineering, Ocean University of China, Qingdao, China
| | - Zhen Guo
- Department of Computer Science, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Peng Chen
- Laboratory of Food Chemistry and Nutrition, College of Food Science and Engineering, Ocean University of China, Qingdao, China
| | - Ranran Ma
- Laboratory of Food Chemistry and Nutrition, College of Food Science and Engineering, Ocean University of China, Qingdao, China
| | - Xiaowen Sun
- Laboratory of Food Chemistry and Nutrition, College of Food Science and Engineering, Ocean University of China, Qingdao, China
| | - Dongfeng Wang
- Laboratory of Food Chemistry and Nutrition, College of Food Science and Engineering, Ocean University of China, Qingdao, China
| | - Junwei Wang
- China Animal Health and Epidemiology Center, Qingdao, Shandong, China
| | - Ying Xu
- Laboratory of Food Chemistry and Nutrition, College of Food Science and Engineering, Ocean University of China, Qingdao, China
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Li C, Xu Y, Li L, Yang X, Wang Y. Acid stress induces cross-protection for cadmium tolerance of multi-stress-tolerant Pichia kudriavzevii by regulating cadmium transport and antioxidant defense system. JOURNAL OF HAZARDOUS MATERIALS 2019; 366:151-159. [PMID: 30513442 DOI: 10.1016/j.jhazmat.2018.11.101] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/27/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
The toxicity of cadmium (Cd) is the major limitation to its removal using microorganisms. The Cd tolerance of Pichia kudriavzevii was obviously enhanced by acid stress based on multi-stress cross-protection. RNA-Seq showed that most differentially expressed genes (DEGs) in the Pentose phosphate pathway, Citrate cycle (TCA cycle), Glycolysis/Gluconeogenesis, Peroxisome and Glutathione metabolism were up-regulated by acid stress. The up-regulated expression of genes related to ATP synthesis (GOR1, ALD5, ADH4, ADH6, MDH2, IDH1, IDH2, and ATP19) and Cd transport (GSTY2, GTO2, GLO2, and YOR1), and the improvement of intracellular GSH level and GST activity, reduced the Cd toxicity towards P. kudriavzevii. Cd efflux by YOR1 played a key role in the decline of intracellular Cd level. Acid stress obviously improved the gene expression levels and activities of antioxidant enzymes (SOD, POD, and CAT), which inhibited the Cd-induced ROS outburst and oxidative damage of proteins and membrane lipids. In addition, the enhanced expression of HSP12 protected P. kudriavzevii from the damage of Cd stress. These results provide some important clues to reconstruct robust strains using for Cd removal in aquatic environments.
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Affiliation(s)
- Chunsheng Li
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China; College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Ying Xu
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China.
| | - Laihao Li
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
| | - Xianqing Yang
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China.
| | - Yueqi Wang
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
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11
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Ye Q, Zhang C, Wang Z, Feng Y, Zhou A, Xie S, Xiang Q, Song E, Zou J. Induction of oxidative stress, apoptosis and DNA damage by koumine in Tetrahymena thermophila. PLoS One 2019; 14:e0212231. [PMID: 30753239 PMCID: PMC6372211 DOI: 10.1371/journal.pone.0212231] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/29/2019] [Indexed: 01/13/2023] Open
Abstract
Koumine is a component of the Chinese medicinal herb Gelsemium elegans and is toxic to vertebrates. We used the ciliate Tetrahymena thermophila as a model to evaluate the toxic effects of this indole alkaloid in eukaryotic microorganisms. Koumine inhibited T. thermophila growth and viability in a dose-dependent manner. Moreover, this drug produced oxidative stress in T. thermophila cells and expressions of antioxidant enzymes were significantly elevated at high koumine levels (p < 0.05). Koumine also caused significant levels of apoptosis (p < 0.05) and induced DNA damage in a dose-dependent manner. Mitophagic vacuoles were present in cells indicating induction of autophagy by this drug. Expression of ATG7, MTT2/4, CYP1 and HSP70 as well as the MAP kinase pathway gene MPK1 and MPK3 were significantly altered after exposed to koumine. This study represents a preliminary toxicological evaluation of koumine in the single celled eukaryote T. thermophila.
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Affiliation(s)
- Qiao Ye
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Chaonan Zhang
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Zhenlu Wang
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yongyong Feng
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Aiguo Zhou
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Shaolin Xie
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Qiong Xiang
- Department of Traditional Chinese Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Enfeng Song
- Department of Traditional Chinese Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Jixing Zou
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- * E-mail:
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12
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Ye Q, Feng Y, Wang Z, Jiang W, Qu Y, Zhang C, Zhou A, Xie S, Zou J. Effects of gelsemine on oxidative stress and DNA damage responses of Tetrahymena thermophila. PeerJ 2018; 6:e6093. [PMID: 30581679 PMCID: PMC6292385 DOI: 10.7717/peerj.6093] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 11/10/2018] [Indexed: 01/01/2023] Open
Abstract
Gelsemine is an important toxic substance extracted from Gelsemium elegans, which has a lot of biological functions in cells and organisms, but its toxicity has been rarely reported in Tetrahymena thermophila. In this study, we used the protozoan T. thermophila as an experimental model to investigate the potential toxicity-induced mechanism of gelsemine in the unicellular eukaryote. Our results clearly showed gelsemine inhibited T. thermophila growth in a dose-dependent manner. This exposure also resulted in oxidative stress on T. thermophila cells and antioxidant enzyme levels were significantly altered at high gelsemine levels (p < 0.05). Gelsemine produced a slight apoptotic effect at the highest (0.8 mg/mL) gelsemine level used here (p < 0.05). Furthermore, the toxin-induced DNA damage in a dose-dependent manner. The ultrastructural analysis also revealed mitophagic vacuoles at 0.4 and 0.8 mg/mL levels of gelsemine exposure. Moreover, expressions of oxidative stress-related and MAP kinase genes were significantly changed after exposure to 0.8 mg/mL level of gelsemine (p < 0.05). Altogether, our results clearly show that gelsemine from G. elegans can inhibit the growth via inducing oxidative stress and DNA damage in T. thermophila cells.
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Affiliation(s)
- Qiao Ye
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China.,Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yongyong Feng
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China.,Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Zhenlu Wang
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China.,Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Wenzhao Jiang
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China.,Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yuexin Qu
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China.,Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Chaonan Zhang
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China.,Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Aiguo Zhou
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China.,Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Shaolin Xie
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China.,Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Jixing Zou
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China.,Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
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13
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Li C, Yang X, Xu Y, Li L, Wang Y. Cadmium detoxification induced by salt stress improves cadmium tolerance of multi-stress-tolerant Pichia kudriavzevii. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 242:845-854. [PMID: 30036838 DOI: 10.1016/j.envpol.2018.07.058] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 07/14/2018] [Accepted: 07/14/2018] [Indexed: 05/28/2023]
Abstract
Heavy metal tolerance of microorganisms is the basis of heavy metal removal by growing cells. In this study, a cross-protection effect generated by salt stress significantly enhanced the cadmium tolerance of multi-stress-tolerant Pichia kudriavzevii. Comparative transcriptome analysis using RNA-Seq linked with physiological and biochemical observation was used to elucidate the underlying mechanisms of the improved cadmium tolerance. The expression of cadmium transport related genes (GSTY2, GLR1, GLO2, YCF1 and YOR1), GSH content and GST activity were elevated by salt stress, suggesting enhanced cadmium conjugation and detoxification in yeast cells. The inhibited cadmium uptake by ZRT1 and enhanced cadmium efflux by YOR1 contributed to the decrease in the intracellular cadmium concentration. The improved expression of antioxidant enzyme genes (SOD1, SOD2, SOD6, CAT1 and PRXIID), along with the enhanced activities of antioxidant enzymes (SOD, CAT and POD) resulted in a decrease in cadmium-induced ROS production, protein carbonylation, lipid peroxidation and cell death. The abundant expression of heat shock protein genes (HSP12, HSP10 and SSC1) and genes related to trehalose synthesis (TPS1 and TSL1) induced by salt stress protected yeast cells against complex stress conditions, contributing to the improved cadmium tolerance. These findings will be useful to develop cadmium-tolerant yeasts for cadmium removal by growing cells.
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Affiliation(s)
- Chunsheng Li
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
| | - Xianqing Yang
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China.
| | - Ying Xu
- Laboratory of Food Chemistry and Nutrition, College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China.
| | - Laihao Li
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
| | - Yueqi Wang
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
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14
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Hu J, Xu Q, Wu M, Meng X, Song R, Gao M. Improved ethanol production in the presence of cadmium ions by a Saccharomyces cerevisiae transformed with a novel cadmium-resistance gene DvCRP1. ENVIRONMENTAL TECHNOLOGY 2016; 37:2945-2952. [PMID: 27020171 DOI: 10.1080/09593330.2016.1170887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 03/20/2016] [Indexed: 06/05/2023]
Abstract
The DvCRP1 gene obtained from Dunaliella viridis is a cadmium-resistance gene that induces cadmium accumulation in microbial and plant cells. In the present study, Saccharomyces cerevisiae was used as a model system to investigate the effect of DvCRP1 on both cadmium detoxification and ethanol production. Inhibitory effects of cadmium (50-300 µmol/L) on growth (29-92%), glucose consumption (23-89%), and ethanol production (17-92%) were observed at 24 h by S. cerevisiae. DvCRP1 alleviated the inhibitory effect of cadmium, with increase in the ethanol production. The established mathematical model showed that the initial inoculation concentration, cadmium concentration, and transformation of DvCRP1 were the most important factors for cell growth, glucose consumption, and ethanol production. Cadmium detoxification of yeast was also enhanced by increasing the initial concentration of yeast cells. Transforming with DvCRP1 further enhanced detoxification, especially at high cadmium concentrations. Transforming with DvCRP1 further enhanced detoxification, especially at high cadmium concentrations (200 µmol/L). The present results evidenced the potential of the insertion of the DvCRP1 gene into yeast for use in bio-refineries during fermentation of heavy metals-contaminated substrates. In addition, this is a promising method for phytoremediation of agricultural soils highly contaminated by heavy metals.
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Affiliation(s)
- Jiajun Hu
- a Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences , Shanghai University , Shanghai , People's Republic of China
| | - Qingyun Xu
- a Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences , Shanghai University , Shanghai , People's Republic of China
| | - Mengnan Wu
- a Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences , Shanghai University , Shanghai , People's Republic of China
| | - Xiangzong Meng
- a Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences , Shanghai University , Shanghai , People's Republic of China
| | - Rentao Song
- a Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences , Shanghai University , Shanghai , People's Republic of China
| | - Mintian Gao
- a Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences , Shanghai University , Shanghai , People's Republic of China
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15
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Mera R, Torres E, Abalde J. Isobolographic analysis of the interaction between cadmium (II) and sodium sulphate: toxicological consequences. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:2264-2278. [PMID: 26658783 DOI: 10.1007/s11356-015-5909-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 12/01/2015] [Indexed: 06/05/2023]
Abstract
Sulphate is an essential nutrient for autotrophic organisms and has been shown to have important implications in certain processes of tolerance to cadmium toxicity. Sodium sulphate is the main salt of sulphate in the natural environments. The concentration of this salt is increasing in the aquatic environments due to environmental pollution. The aim of this study was to investigate, using an analysis of isobolograms, the type and the degree of the interaction between Cd(II) and sodium sulphate in the freshwater microalga Chlamydomonas moewusii. Two blocks of experiments were performed, one at sub-optimal sodium sulphate concentrations (<14.2 mg/L) and the other at supra-optimal concentrations (>14.2 mg/L). Three fixed ratios (2:1, 1:1, and 1:2) of the individual EC50 for cadmium and sodium sulphate were used within each block. The isobolographic analysis of interaction at sub-optimal concentrations showed a stronger antagonistic effect with values of interaction index (γ) between 1.46 and 3.4. However, the isobologram with sodium sulphate at supra-optimal concentrations revealed a slight but significant synergistic effect between both chemicals with an interaction index between 0.54 and 0.64. This synergic effect resulted in the potentiation of the toxic effects of cadmium, synergy that was related to the increase of the ionic strength and of two species of cadmium, CdSO4 (aq), and Cd(SO4)2(2-) , in the medium. Results of the current study suggest that sodium sulphate is able to perform a dual antagonist/synergist effect on cadmium toxicity. This role was concentration dependent.
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Affiliation(s)
- Roi Mera
- Laboratorio de Microbiología, Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidade da Coruña, Campus da Zapateira s/n, 15071, La Coruña, Spain
| | - Enrique Torres
- Laboratorio de Microbiología, Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidade da Coruña, Campus da Zapateira s/n, 15071, La Coruña, Spain.
| | - Julio Abalde
- Laboratorio de Microbiología, Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidade da Coruña, Campus da Zapateira s/n, 15071, La Coruña, Spain
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