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Miralles-Robledillo JM, Martínez-Espinosa RM, Pire C. Transcriptomic profiling of haloarchaeal denitrification through RNA-Seq analysis. Appl Environ Microbiol 2024:e0057124. [PMID: 38814058 DOI: 10.1128/aem.00571-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 04/26/2024] [Indexed: 05/31/2024] Open
Abstract
Denitrification, a crucial biochemical pathway prevalent among haloarchaea in hypersaline ecosystems, has garnered considerable attention in recent years due to its ecological implications. Nevertheless, the underlying molecular mechanisms and genetic regulation governing this respiration/detoxification process in haloarchaea remain largely unexplored. In this study, RNA-sequencing was used to compare the transcriptomes of the haloarchaeon Haloferax mediterranei under oxic and denitrifying conditions, shedding light on the intricate metabolic alterations occurring within the cell, such as the accurate control of the metal homeostasis. Furthermore, the investigation identifies several genes encoding transcriptional regulators and potential accessory proteins with putative roles in denitrification. Among these are bacterioopsin-like transcriptional activators, proteins harboring a domain of unknown function (DUF2249), and cyanoglobin. In addition, the study delves into the genetic regulation of denitrification, finding a regulatory motif within promoter regions that activates numerous denitrification-related genes. This research serves as a starting point for future molecular biology studies in haloarchaea, offering a promising avenue to unravel the intricate mechanisms governing haloarchaeal denitrification, a pathway of paramount ecological importance.IMPORTANCEDenitrification, a fundamental process within the nitrogen cycle, has been subject to extensive investigation due to its close association with anthropogenic activities, and its contribution to the global warming issue, mainly through the release of N2O emissions. Although our comprehension of denitrification and its implications is generally well established, most studies have been conducted in non-extreme environments with mesophilic microorganisms. Consequently, there is a significant knowledge gap concerning extremophilic denitrifiers, particularly those inhabiting hypersaline environments. The significance of this research was to delve into the process of haloarchaeal denitrification, utilizing the complete denitrifier haloarchaeon Haloferax mediterranei as a model organism. This research led to the analysis of the metabolic state of this microorganism under denitrifying conditions and the identification of regulatory signals and genes encoding proteins potentially involved in this pathway, serving as a valuable resource for future molecular studies.
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Affiliation(s)
- Jose María Miralles-Robledillo
- Biochemistry, Molecular Biology, Edaphology and Agricultural Chemistry Department, Faculty of Sciences, Universitat d'Alacant, Alicante, Spain
| | - Rosa María Martínez-Espinosa
- Biochemistry, Molecular Biology, Edaphology and Agricultural Chemistry Department, Faculty of Sciences, Universitat d'Alacant, Alicante, Spain
- Multidisciplinary Institute for Environmental Studies "Ramón Margalef", University of Alicante, Alicante, Spain
| | - Carmen Pire
- Biochemistry, Molecular Biology, Edaphology and Agricultural Chemistry Department, Faculty of Sciences, Universitat d'Alacant, Alicante, Spain
- Multidisciplinary Institute for Environmental Studies "Ramón Margalef", University of Alicante, Alicante, Spain
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Moopantakath J, Imchen M, Anju VT, Busi S, Dyavaiah M, Martínez-Espinosa RM, Kumavath R. Bioactive molecules from haloarchaea: Scope and prospects for industrial and therapeutic applications. Front Microbiol 2023; 14:1113540. [PMID: 37065149 PMCID: PMC10102575 DOI: 10.3389/fmicb.2023.1113540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/14/2023] [Indexed: 04/03/2023] Open
Abstract
Marine environments and salty inland ecosystems encompass various environmental conditions, such as extremes of temperature, salinity, pH, pressure, altitude, dry conditions, and nutrient scarcity. The extremely halophilic archaea (also called haloarchaea) are a group of microorganisms requiring high salt concentrations (2–6 M NaCl) for optimal growth. Haloarchaea have different metabolic adaptations to withstand these extreme conditions. Among the adaptations, several vesicles, granules, primary and secondary metabolites are produced that are highly significant in biotechnology, such as carotenoids, halocins, enzymes, and granules of polyhydroxyalkanoates (PHAs). Among halophilic enzymes, reductases play a significant role in the textile industry and the degradation of hydrocarbon compounds. Enzymes like dehydrogenases, glycosyl hydrolases, lipases, esterases, and proteases can also be used in several industrial procedures. More recently, several studies stated that carotenoids, gas vacuoles, and liposomes produced by haloarchaea have specific applications in medicine and pharmacy. Additionally, the production of biodegradable and biocompatible polymers by haloarchaea to store carbon makes them potent candidates to be used as cell factories in the industrial production of bioplastics. Furthermore, some haloarchaeal species can synthesize nanoparticles during heavy metal detoxification, thus shedding light on a new approach to producing nanoparticles on a large scale. Recent studies also highlight that exopolysaccharides from haloarchaea can bind the SARS-CoV-2 spike protein. This review explores the potential of haloarchaea in the industry and biotechnology as cellular factories to upscale the production of diverse bioactive compounds.
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Affiliation(s)
- Jamseel Moopantakath
- Department of Genomic Science, School of Biological Sciences, Central University of Kerala, Kerala, India
| | - Madangchanok Imchen
- Department of Microbiology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - V. T. Anju
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Siddhardha Busi
- Department of Microbiology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Madhu Dyavaiah
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Rosa María Martínez-Espinosa
- Biochemistry, Molecular Biology, Edaphology and Agricultural Chemistry Department, Faculty of Sciences, University of Alicante, Alicante, Spain
- Multidisciplinary Institute for Environmental Studies “Ramón Margalef”, University of Alicante, Alicante, Spain
- Rosa María Martínez-Espinosa,
| | - Ranjith Kumavath
- Department of Genomic Science, School of Biological Sciences, Central University of Kerala, Kerala, India
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry, India
- *Correspondence: Ranjith Kumavath, ,
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Miralles-Robledillo JM, Bernabeu E, Giani M, Martínez-Serna E, Martínez-Espinosa RM, Pire C. Distribution of Denitrification among Haloarchaea: A Comprehensive Study. Microorganisms 2021; 9:1669. [PMID: 34442748 PMCID: PMC8400030 DOI: 10.3390/microorganisms9081669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/20/2021] [Accepted: 08/02/2021] [Indexed: 11/16/2022] Open
Abstract
Microorganisms from the Halobacteria class, also known as haloarchaea, inhabit a wide range of ecosystems of which the main characteristic is the presence of high salt concentration. These environments together with their microbial communities are not well characterized, but some of the common features that they share are high sun radiation and low availability of oxygen. To overcome these stressful conditions, and more particularly to deal with oxygen limitation, some microorganisms drive alternative respiratory pathways such as denitrification. In this paper, denitrification in haloarchaea has been studied from a phylogenetic point of view. It has been demonstrated that the presence of denitrification enzymes is a quite common characteristic in Halobacteria class, being nitrite reductase and nitric oxide reductase the enzymes with higher co-occurrence, maybe due to their possible role not only in denitrification, but also in detoxification. Moreover, copper-nitrite reductase (NirK) is the only class of respiratory nitrite reductase detected in these microorganisms up to date. The distribution of this alternative respiratory pathway and their enzymes among the families of haloarchaea has also been discussed and related with the environment in which they constitute the major populations. Complete denitrification phenotype is more common in some families like Haloarculaceae and Haloferacaceae, whilst less common in families such as Natrialbaceae and Halorubraceae.
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Affiliation(s)
- Jose María Miralles-Robledillo
- Biochemistry and Molecular Biology Division, Agrochemistry and Biochemistry Department, Faculty of Sciences, University of Alicante, Ap. 99, E-03080 Alicante, Spain; (J.M.M.-R.); (E.B.); (M.G.); (E.M.-S.); (R.M.M.-E.)
| | - Eric Bernabeu
- Biochemistry and Molecular Biology Division, Agrochemistry and Biochemistry Department, Faculty of Sciences, University of Alicante, Ap. 99, E-03080 Alicante, Spain; (J.M.M.-R.); (E.B.); (M.G.); (E.M.-S.); (R.M.M.-E.)
| | - Micaela Giani
- Biochemistry and Molecular Biology Division, Agrochemistry and Biochemistry Department, Faculty of Sciences, University of Alicante, Ap. 99, E-03080 Alicante, Spain; (J.M.M.-R.); (E.B.); (M.G.); (E.M.-S.); (R.M.M.-E.)
| | - Elena Martínez-Serna
- Biochemistry and Molecular Biology Division, Agrochemistry and Biochemistry Department, Faculty of Sciences, University of Alicante, Ap. 99, E-03080 Alicante, Spain; (J.M.M.-R.); (E.B.); (M.G.); (E.M.-S.); (R.M.M.-E.)
| | - Rosa María Martínez-Espinosa
- Biochemistry and Molecular Biology Division, Agrochemistry and Biochemistry Department, Faculty of Sciences, University of Alicante, Ap. 99, E-03080 Alicante, Spain; (J.M.M.-R.); (E.B.); (M.G.); (E.M.-S.); (R.M.M.-E.)
- Multidisciplinary Institute for Environmental Studies “Ramón Margalef”, University of Alicante, Ap. 99, E-03080 Alicante, Spain
| | - Carmen Pire
- Biochemistry and Molecular Biology Division, Agrochemistry and Biochemistry Department, Faculty of Sciences, University of Alicante, Ap. 99, E-03080 Alicante, Spain; (J.M.M.-R.); (E.B.); (M.G.); (E.M.-S.); (R.M.M.-E.)
- Multidisciplinary Institute for Environmental Studies “Ramón Margalef”, University of Alicante, Ap. 99, E-03080 Alicante, Spain
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