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Blackwell AM, Jami-Alahmadi Y, Nasamu AS, Kudo S, Senoo A, Slam C, Tsumoto K, Wohlschlegel JA, Caaveiro JMM, Goldberg DE, Sigala PA. Malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.30.596652. [PMID: 38853871 PMCID: PMC11160694 DOI: 10.1101/2024.05.30.596652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Malaria parasites have evolved unusual metabolic adaptations that specialize them for growth within heme-rich human erythrocytes. During blood-stage infection, Plasmodium falciparum parasites internalize and digest abundant host hemoglobin within the digestive vacuole. This massive catabolic process generates copious free heme, most of which is biomineralized into inert hemozoin. Parasites also express a divergent heme oxygenase (HO)-like protein (PfHO) that lacks key active-site residues and has lost canonical HO activity. The cellular role of this unusual protein that underpins its retention by parasites has been unknown. To unravel PfHO function, we first determined a 2.8 Å-resolution X-ray structure that revealed a highly α-helical fold indicative of distant HO homology. Localization studies unveiled PfHO targeting to the apicoplast organelle, where it is imported and undergoes N-terminal processing but retains most of the electropositive transit peptide. We observed that conditional knockdown of PfHO was lethal to parasites, which died from defective apicoplast biogenesis and impaired isoprenoid-precursor synthesis. Complementation and molecular-interaction studies revealed an essential role for the electropositive N-terminus of PfHO, which selectively associates with the apicoplast genome and enzymes involved in nucleic acid metabolism and gene expression. PfHO knockdown resulted in a specific deficiency in levels of apicoplast-encoded RNA but not DNA. These studies reveal an essential function for PfHO in apicoplast maintenance and suggest that Plasmodium repurposed the conserved HO scaffold from its canonical heme-degrading function in the ancestral chloroplast to fulfill a critical adaptive role in organelle gene expression.
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Li X, Zhu L, Ma R, Zhang X, Lin C, Tang Y, Huang Z, Wang C. Effects of iron additives on the removal of antibiotics and antibiotic resistance genes in anaerobic fermentation of food waste. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 347:119038. [PMID: 37769470 DOI: 10.1016/j.jenvman.2023.119038] [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: 07/07/2023] [Revised: 09/04/2023] [Accepted: 09/17/2023] [Indexed: 09/30/2023]
Abstract
The presence of antibiotics and antibiotic resistance genes (ARGs) in food waste (FW) during anaerobic fermentation poses significant environmental and health risks. This study elucidated the potential of iron additives, specifically 500-nm and 50-nm zero-valent iron (ZVI) and magnetite, in mitigating these contaminants. These findings revealed that 500-nm magnetite significantly reduced tetracyclines by 81.04%, while 500-nm ZVI effectively reduced cefotaxime by 89.90%. Furthermore, both 500-nm and 50-nm ZVI were observed to decrease different types and abundance of heavy metal resistance and virulence genes. Interestingly, while 500-nm ZVI reduced the overall abundance of ARGs by 50%, 500-nm magnetite primarily reduced the diversity of ARGs without significantly impacting their abundance. These results elucidate the efficacy of iron additives in addressing antibiotic contamination and resistance during the anaerobic fermentation process of FW. The findings acquired from this study mitigate the development of innovative and environmentally sustainable technologies for FW treatment, emphasizing the reduction of environmental risks and enhancement of treatment efficiency.
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Affiliation(s)
- Xiaotian Li
- College of Natural Resources and Environment, South China Agricultural University, No. 483 Wushan Road, Tianhe District, Guangzhou, 510642, PR China.
| | - Langping Zhu
- College of Natural Resources and Environment, South China Agricultural University, No. 483 Wushan Road, Tianhe District, Guangzhou, 510642, PR China
| | - Rong Ma
- College of Natural Resources and Environment, South China Agricultural University, No. 483 Wushan Road, Tianhe District, Guangzhou, 510642, PR China
| | - Xiaozhi Zhang
- College of Natural Resources and Environment, South China Agricultural University, No. 483 Wushan Road, Tianhe District, Guangzhou, 510642, PR China
| | - Changquan Lin
- College of Natural Resources and Environment, South China Agricultural University, No. 483 Wushan Road, Tianhe District, Guangzhou, 510642, PR China
| | - Youqian Tang
- College of Natural Resources and Environment, South China Agricultural University, No. 483 Wushan Road, Tianhe District, Guangzhou, 510642, PR China
| | - Zhuoshen Huang
- College of Natural Resources and Environment, South China Agricultural University, No. 483 Wushan Road, Tianhe District, Guangzhou, 510642, PR China
| | - Chunming Wang
- College of Natural Resources and Environment, South China Agricultural University, No. 483 Wushan Road, Tianhe District, Guangzhou, 510642, PR China.
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Reeder BJ. Globin Associated Oxidative Stress. Antioxidants (Basel) 2023; 12:antiox12051077. [PMID: 37237943 DOI: 10.3390/antiox12051077] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
Globins have been studied for their "pseudo-peroxidase" activity for over 70 years, being an ideal model of other kinetically more rapid metalloenzymes [...].
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Affiliation(s)
- Brandon J Reeder
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
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