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Tanimoto H, Umekawa Y, Takahashi H, Goto K, Ito K. Gene expression and metabolite levels converge in the thermogenic spadix of skunk cabbage. PLANT PHYSIOLOGY 2024; 195:1561-1585. [PMID: 38318875 PMCID: PMC11142342 DOI: 10.1093/plphys/kiae059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 01/11/2024] [Accepted: 01/11/2024] [Indexed: 02/07/2024]
Abstract
The inflorescence (spadix) of skunk cabbage (Symplocarpus renifolius) is strongly thermogenic and can regulate its temperature at around 23 °C even when the ambient temperature drops below freezing. To elucidate the mechanisms underlying developmentally controlled thermogenesis and thermoregulation in skunk cabbage, we conducted a comprehensive transcriptome and metabolome analysis across 3 developmental stages of spadix development. Our RNA-seq analysis revealed distinct groups of expressed genes, with selenium-binding protein 1/methanethiol oxidase (SBP1/MTO) exhibiting the highest levels in thermogenic florets. Notably, the expression of alternative oxidase (AOX) was consistently high from the prethermogenic stage through the thermogenic stage in the florets. Metabolome analysis showed that alterations in nucleotide levels correspond with the developmentally controlled and tissue-specific thermogenesis of skunk cabbage, evident by a substantial increase in AMP levels in thermogenic florets. Our study also reveals that hydrogen sulfide, a product of SBP1/MTO, inhibits cytochrome c oxidase (COX)-mediated mitochondrial respiration, while AOX-mediated respiration remains relatively unaffected. Specifically, at lower temperatures, the inhibitory effect of hydrogen sulfide on COX-mediated respiration increases, promoting a shift toward the dominance of AOX-mediated respiration. Finally, despite the differential regulation of genes and metabolites throughout spadix development, we observed a convergence of gene expression and metabolite accumulation patterns during thermogenesis. This synchrony may play a key role in developmentally regulated thermogenesis. Moreover, such convergence during the thermogenic stage in the spadix may provide a solid molecular basis for thermoregulation in skunk cabbage.
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Affiliation(s)
- Haruka Tanimoto
- United Graduate School of Agricultural Science, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Yui Umekawa
- Department of Planning and General Affairs, Akita Research Institute of Food and Brewing, Araya-machi, Akita 010-1623, Japan
| | - Hideyuki Takahashi
- Department of Agriculture, School of Agriculture, Tokai University, Kumamoto 862-8652, Japan
| | - Kota Goto
- Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Kikukatsu Ito
- United Graduate School of Agricultural Science, Iwate University, Morioka, Iwate 020-8550, Japan
- Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
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Weaver RJ, McDonald AE. Mitochondrial alternative oxidase across the tree of life: Presence, absence, and putative cases of lateral gene transfer. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:149003. [PMID: 37557975 DOI: 10.1016/j.bbabio.2023.149003] [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: 01/31/2023] [Revised: 07/27/2023] [Accepted: 08/02/2023] [Indexed: 08/11/2023]
Abstract
The alternative oxidase (AOX) is a terminal oxidase in the electron transport system that plays a role in mitochondrial bioenergetics. The past 20 years of research shows AOX has a wide yet patchy distribution across the tree of life. AOX has been suggested to have a role in stress tolerance, growth, and development in plants, but less is known about its function in other groups, including animals. In this study, we analyzed the taxonomic distribution of AOX across >2800 species representatives from prokaryotes and eukaryotes and developed a standardized workflow for finding and verifying the authenticity of AOX sequences. We found that AOX is limited to proteobacteria among prokaryotes, but is widely distributed in eukaryotes, with the highest prevalence in plants, fungi, and protists. AOX is present in many invertebrates, but is absent in others including most arthropods, and is absent from vertebrates. We found aberrant AOX sequences associated with some animal groups. Some of these aberrant AOXs were contaminants, but we also found putative cases of lateral gene transfer of AOX from fungi and protists to nematodes, springtails, fungus gnats, and rotifers. Our findings provide a robust and detailed analysis of the distribution of AOX and a method for identifying and verifying putative AOX sequences, which will be useful as more sequence data becomes available on public repositories.
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Affiliation(s)
- Ryan J Weaver
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA.
| | - Allison E McDonald
- Department of Biology, Wilfrid Laurier University, Waterloo, Ontario, Canada.
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Xenotopic expression of alternative oxidase (AOX) to study mechanisms of mitochondrial disease. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148947. [PMID: 36481273 DOI: 10.1016/j.bbabio.2022.148947] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 11/17/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022]
Abstract
The mitochondrial respiratory chain or electron transport chain (ETC) facilitates redox reactions which ultimately lead to the reduction of oxygen to water (respiration). Energy released by this process is used to establish a proton electrochemical gradient which drives ATP formation (oxidative phosphorylation, OXPHOS). It also plays an important role in vital processes beyond ATP formation and cellular metabolism, such as heat production, redox and ion homeostasis. Dysfunction of the ETC can thus impair cellular and organismal viability and is thought to be the underlying cause of a heterogeneous group of so-called mitochondrial diseases. Plants, yeasts, and many lower organisms, but not insects and vertebrates, possess an enzymatic mechanism that confers resistance to respiratory stress conditions, i.e., the alternative oxidase (AOX). Even in cells that naturally lack AOX, it is autonomously imported into the mitochondrial compartment upon xenotopic expression, where it refolds and becomes catalytically engaged when the cytochrome segment of the ETC is blocked. AOX was therefore proposed as a tool to study disease etiologies. To this end, AOX has been xenotopically expressed in mammalian cells and disease models of the fruit fly and mouse. Surprisingly, AOX showed remarkable rescue effects in some cases, whilst in others it had no effect or even exacerbated a condition. Here we summarize what has been learnt from the use of AOX in various disease models and discuss issues which still need to be addressed in order to understand the role of the ETC in health and disease.
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Tufail MA, Iltaf J, Zaheer T, Tariq L, Amir MB, Fatima R, Asbat A, Kabeer T, Fahad M, Naeem H, Shoukat U, Noor H, Awais M, Umar W, Ayyub M. Recent advances in bioremediation of heavy metals and persistent organic pollutants: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 850:157961. [PMID: 35963399 DOI: 10.1016/j.scitotenv.2022.157961] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 08/02/2022] [Accepted: 08/06/2022] [Indexed: 06/15/2023]
Abstract
Heavy metals and persistent organic pollutants are causing detrimental effects on the environment. The seepage of heavy metals through untreated industrial waste destroys the crops and lands. Moreover, incineration and combustion of several products are responsible for primary and secondary emissions of pollutants. This review has gathered the remediation strategies, current bioremediation technologies, and their primary use in both in situ and ex situ methods, followed by a detailed explanation for bioremediation over other techniques. However, an amalgam of bioremediation techniques and nanotechnology could be a breakthrough in cleaning the environment by degrading heavy metals and persistant organic pollutants.
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Affiliation(s)
| | - Jawaria Iltaf
- Institute of Chemistry, University of Sargodha, 40100, Pakistan
| | - Tahreem Zaheer
- Department of Biological Physics, Eötvös Loránd University, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary
| | - Leeza Tariq
- Centre of Excellence in Molecular Biology, University of the Punjab, Lahore 53700, Pakistan
| | - Muhammad Bilal Amir
- Key Laboratory of Insect Ecology and Molecular Biology, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266109, China
| | - Rida Fatima
- School of Science, Department of Chemistry, University of Management and Technology, Lahore, Pakistan
| | - Ayesha Asbat
- Department of Pharmacy, The University of Lahore, Lahore, Pakistan
| | - Tahira Kabeer
- Center of Agriculture Biochemistry and Biotechnology CABB, University of Agriculture, Faisalabad, Pakistan
| | - Muhammad Fahad
- Department of Plant Breeding and Genetics, Bahauddin Zakariya University, Multan, Pakistan
| | - Hamna Naeem
- Department of Environmental Sciences, Fatima Jinnah Women University, The Mall, 46000 Rawalpindi, Pakistan
| | - Usama Shoukat
- Integrated Genomics Cellular Development Biology Lab, Department of Entomology, University of Agriculture, Faisalabad, Pakistan
| | - Hazrat Noor
- Department of Microbiology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Muhammad Awais
- International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Wajid Umar
- Institute of Environmental Science, Hungarian University of Agriculture and Life Sciences, Gödöllő 2100, Hungary
| | - Muhaimen Ayyub
- Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad, Pakistan
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