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Qiu X, Hu XM, Tang XX, Huang CH, Jian HH, Lin DH. Metabolic adaptations of Microbacterium sediminis YLB-01 in deep-sea high-pressure environments. Appl Microbiol Biotechnol 2024; 108:170. [PMID: 38265689 DOI: 10.1007/s00253-023-12906-5] [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: 07/10/2023] [Revised: 10/30/2023] [Accepted: 11/07/2023] [Indexed: 01/25/2024]
Abstract
The deep-sea environment is an extremely difficult habitat for microorganisms to survive in due to its intense hydrostatic pressure. However, the mechanisms by which these organisms adapt to such extreme conditions remain poorly understood. In this study, we investigated the metabolic adaptations of Microbacterium sediminis YLB-01, a cold and stress-tolerant microorganism isolated from deep-sea sediments, in response to high-pressure conditions. YLB-01 cells were cultured at normal atmospheric pressure and 28 ℃ until they reached the stationary growth phase. Subsequently, the cells were exposed to either normal pressure or high pressure (30 MPa) at 4 ℃ for 7 days. Using NMR-based metabolomic and proteomic analyses of YLB-01 cells exposed to high-pressure conditions, we observed significant metabolic changes in several metabolic pathways, including amino acid, carbohydrate, and lipid metabolism. In particular, the high-pressure treatment stimulates cell division and triggers the accumulation of UDP-glucose, a critical factor in cell wall formation. This finding highlights the adaptive strategies used by YLB-01 cells to survive in the challenging high-pressure environments of the deep sea. Specifically, we discovered that YLB-01 cells regulate amino acid metabolism, promote carbohydrate metabolism, enhance cell wall synthesis, and improve cell membrane fluidity in response to high pressure. These adaptive mechanisms play essential roles in supporting the survival and growth of YLB-01 in high-pressure conditions. Our study offers valuable insights into the molecular mechanisms underlying the metabolic adaptation of deep-sea microorganisms to high-pressure environments. KEY POINTS: • NMR-based metabolomic and proteomic analyses were conducted on Microbacterium sediminis YLB-01 to investigate the significant alterations in several metabolic pathways in response to high-pressure treatment. • YLB-01 cells used adaptive strategies (such as regulated amino acid metabolism, promoted carbohydrate metabolism, enhanced cell wall synthesis, and improved cell membrane fluidity) to survive in the challenging high-pressure environment of the deep sea. • High-pressure treatment stimulated cell division and triggered the accumulation of UDP-glucose, a critical factor in cell wall formation, in Microbacterium sediminis YLB-01 cells.
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Affiliation(s)
- Xu Qiu
- Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Xiao-Min Hu
- Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Xi-Xiang Tang
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources, Fujian Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China.
| | - Cai-Hua Huang
- Research and Communication Center of Exercise and Health, Xiamen University of Technology, Xiamen, China
| | - Hua-Hua Jian
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Dong-Hai Lin
- Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.
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2
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Lai D, Hedlund BP, Mau RL, Jiao JY, Li J, Hayer M, Dijkstra P, Schwartz E, Li WJ, Dong H, Palmer M, Dodsworth JA, Zhou EM, Hungate BA. Resource partitioning and amino acid assimilation in a terrestrial geothermal spring. THE ISME JOURNAL 2023; 17:2112-2122. [PMID: 37741957 PMCID: PMC10579274 DOI: 10.1038/s41396-023-01517-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 08/31/2023] [Accepted: 09/13/2023] [Indexed: 09/25/2023]
Abstract
High-temperature geothermal springs host simplified microbial communities; however, the activities of individual microorganisms and their roles in the carbon cycle in nature are not well understood. Here, quantitative stable isotope probing (qSIP) was used to track the assimilation of 13C-acetate and 13C-aspartate into DNA in 74 °C sediments in Gongxiaoshe Hot Spring, Tengchong, China. This revealed a community-wide preference for aspartate and a tight coupling between aspartate incorporation into DNA and the proliferation of aspartate utilizers during labeling. Both 13C incorporation into DNA and changes in the abundance of taxa during incubations indicated strong resource partitioning and a significant phylogenetic signal for aspartate incorporation. Of the active amplicon sequence variants (ASVs) identified by qSIP, most could be matched with genomes from Gongxiaoshe Hot Spring or nearby springs with an average nucleotide similarity of 99.4%. Genomes corresponding to aspartate primary utilizers were smaller, near-universally encoded polar amino acid ABC transporters, and had codon preferences indicative of faster growth rates. The most active ASVs assimilating both substrates were not abundant, suggesting an important role for the rare biosphere in the community response to organic carbon addition. The broad incorporation of aspartate into DNA over acetate by the hot spring community may reflect dynamic cycling of cell lysis products in situ or substrates delivered during monsoon rains and may reflect N limitation.
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Affiliation(s)
- Dengxun Lai
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Brian P Hedlund
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA.
- Nevada Institute for Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV, USA.
| | - Rebecca L Mau
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Jian-Yu Jiao
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Junhui Li
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Michaela Hayer
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Paul Dijkstra
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Egbert Schwartz
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Hailiang Dong
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, China and Department of Geology and Environmental Earth Science, Miami University, Oxford, OH, USA
| | - Marike Palmer
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Jeremy A Dodsworth
- Department of Biology, California State University, San Bernardino, CA, USA
| | - En-Min Zhou
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
- School of Resource Environment and Earth Science, Yunnan University, Kunming, China
| | - Bruce A Hungate
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.
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3
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Couvillion SP, Danczak RE, Naylor D, Smith ML, Stratton KG, Paurus VL, Bloodsworth KJ, Farris Y, Schmidt DJ, Richardson RE, Bramer LM, Fansler SJ, Nakayasu ES, McDermott JE, Metz TO, Lipton MS, Jansson JK, Hofmockel KS. Rapid remodeling of the soil lipidome in response to a drying-rewetting event. MICROBIOME 2023; 11:34. [PMID: 36849975 PMCID: PMC9969633 DOI: 10.1186/s40168-022-01427-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 11/15/2022] [Indexed: 06/18/2023]
Abstract
BACKGROUND Microbiomes contribute to multiple ecosystem services by transforming organic matter in the soil. Extreme shifts in the environment, such as drying-rewetting cycles during drought, can impact the microbial metabolism of organic matter by altering microbial physiology and function. These physiological responses are mediated in part by lipids that are responsible for regulating interactions between cells and the environment. Despite this critical role in regulating the microbial response to stress, little is known about microbial lipids and metabolites in the soil or how they influence phenotypes that are expressed under drying-rewetting cycles. To address this knowledge gap, we conducted a soil incubation experiment to simulate soil drying during a summer drought of an arid grassland, then measured the response of the soil lipidome and metabolome during the first 3 h after wet-up. RESULTS Reduced nutrient access during soil drying incurred a replacement of membrane phospholipids, resulting in a diminished abundance of multiple phosphorus-rich membrane lipids. The hot and dry conditions increased the prevalence of sphingolipids and lipids containing long-chain polyunsaturated fatty acids, both of which are associated with heat and osmotic stress-mitigating properties in fungi. This novel finding suggests that lipids commonly present in eukaryotes such as fungi may play a significant role in supporting community resilience displayed by arid land soil microbiomes during drought. As early as 10 min after rewetting dry soil, distinct changes were observed in several lipids that had bacterial signatures including a rapid increase in the abundance of glycerophospholipids with saturated and short fatty acid chains, prototypical of bacterial membrane lipids. Polar metabolites including disaccharides, nucleic acids, organic acids, inositols, and amino acids also increased in abundance upon rewetting. This rapid metabolic reactivation and growth after rewetting coincided with an increase in the relative abundance of firmicutes, suggesting that members of this phylum were positively impacted by rewetting. CONCLUSIONS Our study revealed specific changes in lipids and metabolites that are indicative of stress adaptation, substrate use, and cellular recovery during soil drying and subsequent rewetting. The drought-induced nutrient limitation was reflected in the lipidome and polar metabolome, both of which rapidly shifted (within hours) upon rewet. Reduced nutrient access in dry soil caused the replacement of glycerophospholipids with phosphorus-free lipids and impeded resource-expensive osmolyte accumulation. Elevated levels of ceramides and lipids with long-chain polyunsaturated fatty acids in dry soil suggest that lipids likely play an important role in the drought tolerance of microbial taxa capable of synthesizing these lipids. An increasing abundance of bacterial glycerophospholipids and triacylglycerols with fatty acids typical of bacteria and polar metabolites suggest a metabolic recovery in representative bacteria once the environmental conditions are conducive for growth. These results underscore the importance of the soil lipidome as a robust indicator of microbial community responses, especially at the short time scales of cell-environment reactions. Video Abstract.
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Affiliation(s)
- Sneha P Couvillion
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Robert E Danczak
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Dan Naylor
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Montana L Smith
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Kelly G Stratton
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Vanessa L Paurus
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Kent J Bloodsworth
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Yuliya Farris
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Darren J Schmidt
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Rachel E Richardson
- National Security Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Lisa M Bramer
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Sarah J Fansler
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Ernesto S Nakayasu
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Jason E McDermott
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, USA
| | - Thomas O Metz
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Mary S Lipton
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Janet K Jansson
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Kirsten S Hofmockel
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA.
- Department of Agronomy, Iowa State University, Ames, IA, USA.
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Tamby A, Sinninghe Damsté JS, Villanueva L. Microbial membrane lipid adaptations to high hydrostatic pressure in the marine environment. Front Mol Biosci 2023; 9:1058381. [PMID: 36685280 PMCID: PMC9853057 DOI: 10.3389/fmolb.2022.1058381] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/29/2022] [Indexed: 01/09/2023] Open
Abstract
The deep-sea is characterized by extreme conditions, such as high hydrostatic pressure (HHP) and near-freezing temperature. Piezophiles, microorganisms adapted to high pressure, have developed key strategies to maintain the integrity of their lipid membrane at these conditions. The abundance of specific membrane lipids, such as those containing unsaturated and branched-chain fatty acids, rises with increasing HHP. Nevertheless, this strategy is not universal among piezophiles, highlighting the need to further understand the effects of HHP on microbial lipid membranes. Challenges in the study of lipid membrane adaptations by piezophiles also involve methodological developments, cross-adaptation studies, and insight into slow-growing piezophiles. Moreover, the effects of HHP on piezophiles are often difficult to disentangle from effects caused by low temperature that are often characteristic of the deep sea. Here, we review the knowledge of membrane lipid adaptation strategies of piezophiles, and put it into the perspective of marine systems, highlighting the future challenges of research studying the effects of HHP on the microbial lipid composition.
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Affiliation(s)
- Anandi Tamby
- Department of Marine Microbiology and Biogeochemistry (MMB), NIOZ Royal Netherlands Institute for Sea Research, Den Burg, Netherlands,*Correspondence: Anandi Tamby,
| | - Jaap S. Sinninghe Damsté
- Department of Marine Microbiology and Biogeochemistry (MMB), NIOZ Royal Netherlands Institute for Sea Research, Den Burg, Netherlands,Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, Netherlands
| | - Laura Villanueva
- Department of Marine Microbiology and Biogeochemistry (MMB), NIOZ Royal Netherlands Institute for Sea Research, Den Burg, Netherlands,Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, Netherlands
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Somayaji A, Dhanjal CR, Lingamsetty R, Vinayagam R, Selvaraj R, Varadavenkatesan T, Govarthanan M. An insight into the mechanisms of homeostasis in extremophiles. Microbiol Res 2022; 263:127115. [PMID: 35868258 DOI: 10.1016/j.micres.2022.127115] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 07/07/2022] [Accepted: 07/07/2022] [Indexed: 01/10/2023]
Abstract
The homeostasis of extremophiles is one that is a diamond hidden in the rough. The way extremophiles adapt to their extreme environments gives a clue into the true extent of what is possible when it comes to life. The discovery of new extremophiles is ever-expanding and an explosion of knowledge surrounding their successful existence in extreme environments is obviously perceived in scientific literature. The present review paper aims to provide a comprehensive view on the different mechanisms governing the extreme adaptations of extremophiles, along with insights and discussions on what the limits of life can possibly be. The membrane adaptations that are vital for survival are discussed in detail. It was found that there are many alterations in the genetic makeup of such extremophiles when compared to their mesophilic counterparts. Apart from the several proteins involved, the significance of chaperones, efflux systems, DNA repair proteins and a host of other enzymes that adapt to maintain functionality, are enlisted, and explained. A deeper understanding of the underlying mechanisms could have a plethora of applications in the industry. There are cases when certain microbes can withstand extreme doses of antibiotics. Such microbes accumulate numerous genetic elements (or plasmids) that possess genes for multiple drug resistance (MDR). A deeper understanding of such mechanisms helps in the development of potential approaches and therapeutic schemes for treating pathogen-mediated outbreaks. An in-depth analysis of the parameters - radiation, pressure, temperature, pH value and metal resistance - are discussed in this review, and the key to survival in these precarious niches is described.
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Affiliation(s)
- Adithi Somayaji
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India; Manipal Biomachines, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Chetan Roger Dhanjal
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India; Manipal Biomachines, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Rathnamegha Lingamsetty
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India; Manipal Biomachines, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Ramesh Vinayagam
- Department of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Raja Selvaraj
- Department of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Thivaharan Varadavenkatesan
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India.
| | - Muthusamy Govarthanan
- Department of Environmental Engineering, Kyungpook National University, Daegu, South Korea; Department of Biomaterials, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Chennai 600077, India.
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6
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Shah AM, Yang W, Mohamed H, Zhang Y, Song Y. Microbes: A Hidden Treasure of Polyunsaturated Fatty Acids. Front Nutr 2022; 9:827837. [PMID: 35369055 PMCID: PMC8968027 DOI: 10.3389/fnut.2022.827837] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/21/2022] [Indexed: 12/26/2022] Open
Abstract
Microbes have gained a lot of attention for their potential in producing polyunsaturated fatty acids (PUFAs). PUFAs are gaining scientific interest due to their important health-promoting effects on higher organisms including humans. The current sources of PUFAs (animal and plant) have associated limitations that have led to increased interest in microbial PUFAs as most reliable alternative source. The focus is on increasing the product value of existing oleaginous microbes or discovering new microbes by implementing new biotechnological strategies in order to compete with other sources. The multidisciplinary approaches, including metabolic engineering, high-throughput screening, tapping new microbial sources, genome-mining as well as co-culturing and elicitation for the production of PUFAs, have been considered and discussed in this review. The usage of agro-industrial wastes as alternative low-cost substrates in fermentation for high-value single-cell oil production has also been discussed. Multidisciplinary approaches combined with new technologies may help to uncover new microbial PUFA sources that may have nutraceutical and biotechnological importance.
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Affiliation(s)
- Aabid Manzoor Shah
- Colin Ratledge Center of Microbial Lipids, School of Agriculture Engineering and Food Sciences, Shandong University of Technology, Zibo, China
| | - Wu Yang
- Colin Ratledge Center of Microbial Lipids, School of Agriculture Engineering and Food Sciences, Shandong University of Technology, Zibo, China
| | - Hassan Mohamed
- Colin Ratledge Center of Microbial Lipids, School of Agriculture Engineering and Food Sciences, Shandong University of Technology, Zibo, China
- Department of Botany and Microbiology, Faculty of Science, Al-Azhar University, Assiut, Egypt
| | - Yingtong Zhang
- Institute of Agricultural Facilities and Equipment, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Yuanda Song
- Colin Ratledge Center of Microbial Lipids, School of Agriculture Engineering and Food Sciences, Shandong University of Technology, Zibo, China
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Keaney D, Lucey B, Quinn N, Finn K. The Effects of Freeze-Thaw and UVC Radiation on Microbial Survivability in a Selected Mars-like Environment. Microorganisms 2022; 10:microorganisms10030576. [PMID: 35336151 PMCID: PMC8956125 DOI: 10.3390/microorganisms10030576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/23/2022] [Accepted: 03/04/2022] [Indexed: 02/06/2023] Open
Abstract
The purpose of this study was to determine survivability of Escherichia coli, Deinococcus radiodurans and Paraburkholderia fungorum under Mars-simulated conditions for freeze-thawing (−80 °C to +30 °C) and UV exposure alone and in combination. E. coli ATCC 25922, D. radiodurans and P. fungorum remained viable following 20 successive freeze-thaw cycles, exhibiting viabilities of 2.3%, 96% and 72.6%, respectively. E. coli ATCC 9079 was non-recoverable by cycle 9. When exposed to UV irradiation, cells withstood doses of 870 J/m2 (E. coli ATCC 25922), 200 J/m2 (E. coli ATCC 9079), 50,760 J/m2 (D. radiodurans) and 44,415 J/m2 (P. fungorum). Data suggests P. fungorum is highly UV-resistant. Combined freeze-thawing with UV irradiation showed freezing increased UV resistance in E. coli ATCC 25922, E. coli DSM 9079 and D. radiodurans by 6-fold, 30-fold and 1.2-fold, respectively. Conversely, freezing caused P. fungorum to exhibit a 1.75-fold increase in UV susceptibility. Strain-dependent experimentation demonstrated that freezing increases UV resistance and prolongs survival. These findings suggest that exposure to short wavelength UV rays (254 nm) and temperature cycles resembling the daily fluctuating conditions on Mars do not significantly affect survival of D. radiodurans, P. fungorum and E. coli ATCC 25922 following 20 days of exposure.
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Affiliation(s)
- Daniel Keaney
- Department of Biological Sciences, Munster Technological University, Bishopstown, T12 P928 Cork, Ireland; (D.K.); (B.L.)
| | - Brigid Lucey
- Department of Biological Sciences, Munster Technological University, Bishopstown, T12 P928 Cork, Ireland; (D.K.); (B.L.)
| | - Noreen Quinn
- Department of Mathematics, Munster Technological University, Bishopstown, T12 P928 Cork, Ireland;
| | - Karen Finn
- Department of Analytical, Biopharmaceutical and Medical Sciences, Galway-Mayo Institute of Technology, Old Dublin Road, H91 T8NW Galway, Ireland
- Correspondence:
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Svetashev VI. Investigation of Deep-Sea Ecosystems Using Marker Fatty Acids: Sources of Essential Polyunsaturated Fatty Acids in Abyssal Megafauna. Mar Drugs 2021; 20:md20010017. [PMID: 35049873 PMCID: PMC8779288 DOI: 10.3390/md20010017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/17/2021] [Accepted: 12/18/2021] [Indexed: 11/16/2022] Open
Abstract
Abyssal seafloor ecosystems cover more than 50% of the Earth's surface. Being formed by mainly heterotrophic organisms, they depend on the flux of particulate organic matter (POM) photosynthetically produced in the surface layer of the ocean. As dead phytoplankton sinks from the euphotic to the abyssal zone, the trophic value of POM and the concentration of essential polyunsaturated fatty acids (PUFA) decrease. This results in pronounced food periodicity and limitations for bottom dwellers. Deep-sea invertebrate seston eaters and surface deposit feeders consume the sinking POM. Other invertebrates utilize different food items that have undergone a trophic upgrade, with PUFA synthesized from saturated and monounsaturated FA. Foraminifera and nematodes can synthesize arachidonic acid (AA), eicosapentaenoic acid (EPA), while some barophylic bacteria produce EPA and/or docosahexaenoic acid. FA analysis of deep-sea invertebrates has shown high levels of PUFA including, in particular, arachidonic acid, bacterial FA, and a vast number of new and uncommon fatty acids such as 21:4(n-7), 22:4(n-8), 23:4(n-9), and 22:5(n-5) characteristic of foraminifera. We suppose that bacteria growing on detritus having a low trophic value provide the first trophic upgrading of organic matter for foraminifera and nematodes. In turn, these metazoans perform the second-stage upgrading for megafauna invertebrates. Deep-sea megafauna, including major members of Echinodermata, Mollusca, and Polychaeta display FA markers characteristic of bacteria, foraminifera, and nematodes and reveal new markers in the food chain.
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Affiliation(s)
- Vasily I Svetashev
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, 17 Palchevskogo Str., Vladivostok 690041, Russia
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9
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Schnorr SL, Berry D. Lipid synthesis at the trophic base as the source for energy management to build complex structures. Curr Opin Biotechnol 2021; 73:364-373. [PMID: 34735986 DOI: 10.1016/j.copbio.2021.09.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/20/2021] [Accepted: 09/29/2021] [Indexed: 11/26/2022]
Abstract
The review explores the ecological basis for bacterial lipid metabolism in marine and terrestrial ecosystems. We discuss ecosystem stressors that provoked early organisms to modify their lipid membrane structures, and where these stressors are found across a variety of environments. A major role of lipid membranes is to manage cellular energy utility, including how energy is used for signal propagation. As different environments are imbued with properties that necessitate variation in energy regulation, bacterial lipid synthesis has undergone incalculable permutations of functional trial and error. This may hold clues for how biotechnology can improvise a short-hand version of the evolutionary gauntlet to stimulate latent functional competences for the synthesis of rare lipids. Reducing human reliance on marine resources and deriving solutions for production of essential nutrients is a pressing problem in sustainable agriculture and aquaculture, as well as timely considering the increasing fragility of human health in an aging population.
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Affiliation(s)
- Stephanie L Schnorr
- Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria; Konrad Lorenz Institute for Evolution and Cognition Research, Klosterneuburg, Austria
| | - David Berry
- Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria.
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10
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Chan J, Geng D, Pan B, Zhang Q, Xu Q. Metagenomic Insights Into the Structure and Function of Intestinal Microbiota of the Hadal Amphipods. Front Microbiol 2021; 12:668989. [PMID: 34163447 PMCID: PMC8216301 DOI: 10.3389/fmicb.2021.668989] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/26/2021] [Indexed: 11/13/2022] Open
Abstract
Hadal trenches are the deepest known areas of the ocean. Amphipods are considered to be the dominant scavengers in the hadal food webs. The studies on the structure and function of the hadal intestinal microbiotas are largely lacking. Here, the intestinal microbiotas of three hadal amphipods, Hirondellea gigas, Scopelocheirus schellenbergi, and Alicella gigantea, from Mariana Trench, Marceau Trench, and New Britain Trench, respectively, were investigated. The taxonomic analysis identified 358 microbial genera commonly shared within the three amphipods. Different amphipod species possessed their own characteristic dominant microbial component, Psychromonas in H. gigas and Candidatus Hepatoplasma in A. gigantea and S. schellenbergi. Functional composition analysis showed that “Carbohydrate Metabolism,” “Lipid Metabolism,” “Cell Motility,” “Replication and Repair,” and “Membrane Transport” were among the most represented Gene Ontology (GO) Categories in the gut microbiotas. To test the possible functions of “Bacterial Chemotaxis” within the “Cell Motility” category, the methyl-accepting chemotaxis protein (MCP) gene involved in the “Bacterial Chemotaxis” pathway was obtained and used for swarming motility assays. Results showed that bacteria transformed with the gut bacterial MCP gene showed significantly faster growths compared with the control group, suggesting MCP promoted the bacterial swimming capability and nutrient utilization ability. This result suggested that hadal gut microbes could promote their survival in poor nutrient conditions by enhancing chemotaxis and motility. In addition, large quantities of probiotic genera were detected in the hadal amphipod gut microbiotas, which indicated that those probiotics would be possible contributors for promoting the host’s growth and development, which could facilitate adaptation of hadal amphipods to the extreme environment.
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Affiliation(s)
- Jiulin Chan
- Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources, Ministry of Education, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
| | - Daoqiang Geng
- Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources, Ministry of Education, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
| | - Binbin Pan
- Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources, Ministry of Education, College of Marine Sciences, Shanghai Ocean University, Shanghai, China.,Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
| | - Qiming Zhang
- Shanghai Rainbowfish Ocean Technology Co., Ltd, Shanghai, China
| | - Qianghua Xu
- Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources, Ministry of Education, College of Marine Sciences, Shanghai Ocean University, Shanghai, China.,Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China.,National Distant-water Fisheries Engineering Research Center, Shanghai Ocean University, Shanghai, China
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11
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Rojas-Jimenez K, Araya-Lobo A, Quesada-Perez F, Akerman-Sanchez J, Delgado-Duran B, Ganzert L, Zavialov PO, Alymkulov S, Kirillin G, Grossart HP. Variation of bacterial communities along the vertical gradient in Lake Issyk Kul, Kyrgyzstan. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:337-347. [PMID: 33538408 DOI: 10.1111/1758-2229.12935] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/19/2021] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
We explored the diversity and community composition of bacteria along a vertical gradient in Lake Issyk Kul, Kyrgyzstan, one of the world's largest and deepest brackish lakes. We identified 4904 bacterial amplicon sequence variants based on the 16S rRNA gene analysis and determined significant changes in the composition, responding mainly to depth and salinity. A higher abundance of Proteobacteria and Bacteroidetes was observed in the surface waters and lake tributaries. Cyanobacteria were more abundant in the deep chlorophyll maximum from 28.5 to 128 m, while Planctomycetes and Chloroflexi were dominant in the deepest layers, from 128 to 600 m. According to our machine learning analyses, depth and temperature were the most critical environmental factors, with strong effects on Proteobacteria, Planctomycetes and Chloroflexi, while oxygen was associated with the variations in Cyanobacteria. We also observed that with increasing depth, the alpha diversity values increased. The dominance of Planctomycetes and Chloroflexi in the deepest layers can only be seen in a few lakes of the world. However, the lake is facing increasing anthropogenic and climatic pressure. There is an urgent need to understand better the ecological role and function of these unique deep-water microbial communities.
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Affiliation(s)
| | - Alex Araya-Lobo
- Escuela de Biología, Universidad de Costa Rica, San José, 11501, Costa Rica
| | | | | | | | - Lars Ganzert
- Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Alte Fischerhuette 2, Stechlin, D-16775, Germany
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section 3.7 Geomicrobiology, Telegrafenberg C-422, Potsdam, 14473, Germany
- University of Goettingen, Experimental Phycology and Culture Collection of Algae (EPSAG), Nikolausberger Weg 18, Goettingen, 37073, Germany
| | | | - Salmor Alymkulov
- Institute of Physics, National Academy of Sciences of Kyrgyz Republic, Chui Avenue, 265-a, Bishkek, 720071, Kyrgyzstan
| | - Georgiy Kirillin
- Department of Ecohydrology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin, D-12587, Germany
| | - Hans-Peter Grossart
- Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Alte Fischerhuette 2, Stechlin, D-16775, Germany
- Institute for Biochemistry and Biology, Potsdam University, Maulbeerallee 2, Potsdam, 14469, Germany
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12
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Moosmann B, Schindeldecker M, Hajieva P. Cysteine, glutathione and a new genetic code: biochemical adaptations of the primordial cells that spread into open water and survived biospheric oxygenation. Biol Chem 2021; 401:213-231. [PMID: 31318686 DOI: 10.1515/hsz-2019-0232] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 07/08/2019] [Indexed: 12/13/2022]
Abstract
Life most likely developed under hyperthermic and anaerobic conditions in close vicinity to a stable geochemical source of energy. Epitomizing this conception, the first cells may have arisen in submarine hydrothermal vents in the middle of a gradient established by the hot and alkaline hydrothermal fluid and the cooler and more acidic water of the ocean. To enable their escape from this energy-providing gradient layer, the early cells must have overcome a whole series of obstacles. Beyond the loss of their energy source, the early cells had to adapt to a loss of external iron-sulfur catalysis as well as to a formidable temperature drop. The developed solutions to these two problems seem to have followed the principle of maximum parsimony: Cysteine was introduced into the genetic code to anchor iron-sulfur clusters, and fatty acid unsaturation was installed to maintain lipid bilayer viscosity. Unfortunately, both solutions turned out to be detrimental when the biosphere became more oxidizing after the evolution of oxygenic photosynthesis. To render cysteine thiol groups and fatty acid unsaturation compatible with life under oxygen, numerous counter-adaptations were required including the advent of glutathione and the addition of the four latest amino acids (methionine, tyrosine, tryptophan, selenocysteine) to the genetic code. In view of the continued diversification of derived antioxidant mechanisms, it appears that modern life still struggles with the initially developed strategies to escape from its hydrothermal birthplace. Only archaea may have found a more durable solution by entirely exchanging their lipid bilayer components and rigorously restricting cysteine usage.
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Affiliation(s)
- Bernd Moosmann
- Evolutionary Biochemistry and Redox Medicine, Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, D-55128 Mainz, Germany
| | - Mario Schindeldecker
- Evolutionary Biochemistry and Redox Medicine, Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, D-55128 Mainz, Germany
| | - Parvana Hajieva
- Cellular Adaptation Group, Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, D-55128 Mainz, Germany
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13
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DeLong EF. Genome-enabled exploration of microbial ecology and evolution in the sea: a rising tide lifts all boats. Environ Microbiol 2021; 23:1301-1321. [PMID: 33459471 PMCID: PMC8049014 DOI: 10.1111/1462-2920.15403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 11/26/2022]
Abstract
As a young bacteriologist just launching my career during the early days of the 'microbial revolution' in the 1980s, I was fortunate to participate in some early discoveries, and collaborate in the development of cross-disciplinary methods now commonly referred to as "metagenomics". My early scientific career focused on applying phylogenetic and genomic approaches to characterize 'wild' bacteria, archaea and viruses in their natural habitats, with an emphasis on marine systems. These central interests have not changed very much for me over the past three decades, but knowledge, methodological advances and new theoretical perspectives about the microbial world certainly have. In this invited 'How we did it' perspective, I trace some of the trajectories of my lab's collective efforts over the years, including phylogenetic surveys of microbial assemblages in marine plankton and sediments, development of microbial community gene- and genome-enabled surveys, and application of genome-guided, cultivation-independent functional characterization of novel enzymes, pathways and their relationships to in situ biogeochemistry. Throughout this short review, I attempt to acknowledge, all the mentors, students, postdocs and collaborators who enabled this research. Inevitably, a brief autobiographical review like this cannot be fully comprehensive, so sincere apologies to any of my great colleagues who are not explicitly mentioned herein. I salute you all as well!
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Affiliation(s)
- Edward F DeLong
- Daniel K. Inouye Centre for Microbial Oceanography: Research and Education, University of Hawaii, Manoa, Honolulu, HI, 96822, USA
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14
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Zhu XY, Liu J, Xue CX, Tian J, Zhang XH. Shift and Metabolic Potentials of Microbial Eukaryotic Communities Across the Full Depths of the Mariana Trench. Front Microbiol 2021; 11:603692. [PMID: 33537012 PMCID: PMC7848797 DOI: 10.3389/fmicb.2020.603692] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 12/15/2020] [Indexed: 12/04/2022] Open
Abstract
Microbial eukaryotes are widespread and play important roles in marine ecosystems. However, their ecological characteristics in the deep sea (>1,000 m), especially hadal trenches, were largely unknown. Here, we investigated the diversity and metabolic potentials of microbial eukaryotes along the whole water column of the Mariana Trench by metagenomics. Our results showed clear depth-related distribution of microbial eukaryotic community and associated metabolic potentials. Surface seawater was dominated by phototrophic/mixotrophic groups (e.g., Dinoflagellata) and genes involved in biosynthesis (photosynthesis and fatty acid biosynthesis), while deep (bathypelagic and/or hadal) seawaters were enriched with heterotrophic groups (e.g., Bicoecea) and genes related to digestion (lysosomal enzymes and V-type ATPase) and carbohydrate metabolism. Co-occurrence analysis revealed high intra-domain connectivity, indicating that microbial eukaryotic composition was more influenced by microbial eukaryotes themselves than bacteria. Increased abundance of genes associated with unsaturated fatty acid biosynthesis likely plays a role in resisting high hydrostatic pressure. Top1 and hupB genes, responsible for the formation and stabilization of DNA structure, were unique and abundant in the hadal zone and thus may be helpful to stabilize DNA structure in the deep sea. Overall, our results provide insights into the distribution and potential adaptability of microbial eukaryotes in the hadal zone.
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Affiliation(s)
- Xiao-Yu Zhu
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Jiwen Liu
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Chun-Xu Xue
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Jiwei Tian
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Xiao-Hua Zhang
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
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15
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Peoples LM, Kyaw TS, Ugalde JA, Mullane KK, Chastain RA, Yayanos AA, Kusube M, Methé BA, Bartlett DH. Distinctive gene and protein characteristics of extremely piezophilic Colwellia. BMC Genomics 2020; 21:692. [PMID: 33023469 PMCID: PMC7542103 DOI: 10.1186/s12864-020-07102-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 09/24/2020] [Indexed: 01/05/2023] Open
Abstract
Background The deep ocean is characterized by low temperatures, high hydrostatic pressures, and low concentrations of organic matter. While these conditions likely select for distinct genomic characteristics within prokaryotes, the attributes facilitating adaptation to the deep ocean are relatively unexplored. In this study, we compared the genomes of seven strains within the genus Colwellia, including some of the most piezophilic microbes known, to identify genomic features that enable life in the deep sea. Results Significant differences were found to exist between piezophilic and non-piezophilic strains of Colwellia. Piezophilic Colwellia have a more basic and hydrophobic proteome. The piezophilic abyssal and hadal isolates have more genes involved in replication/recombination/repair, cell wall/membrane biogenesis, and cell motility. The characteristics of respiration, pilus generation, and membrane fluidity adjustment vary between the strains, with operons for a nuo dehydrogenase and a tad pilus only present in the piezophiles. In contrast, the piezosensitive members are unique in having the capacity for dissimilatory nitrite and TMAO reduction. A number of genes exist only within deep-sea adapted species, such as those encoding d-alanine-d-alanine ligase for peptidoglycan formation, alanine dehydrogenase for NADH/NAD+ homeostasis, and a SAM methyltransferase for tRNA modification. Many of these piezophile-specific genes are in variable regions of the genome near genomic islands, transposases, and toxin-antitoxin systems. Conclusions We identified a number of adaptations that may facilitate deep-sea radiation in members of the genus Colwellia, as well as in other piezophilic bacteria. An enrichment in more basic and hydrophobic amino acids could help piezophiles stabilize and limit water intrusion into proteins as a result of high pressure. Variations in genes associated with the membrane, including those involved in unsaturated fatty acid production and respiration, indicate that membrane-based adaptations are critical for coping with high pressure. The presence of many piezophile-specific genes near genomic islands highlights that adaptation to the deep ocean may be facilitated by horizontal gene transfer through transposases or other mobile elements. Some of these genes are amenable to further study in genetically tractable piezophilic and piezotolerant deep-sea microorganisms.
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Affiliation(s)
- Logan M Peoples
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093-0202, USA.,Flathead Lake Biological Station, University of Montana, Polson, MT, 59860, USA
| | - Than S Kyaw
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093-0202, USA
| | - Juan A Ugalde
- Millennium Initiative for Collaborative Research on Bacterial Resistance (MICROB-R), Santiago, Chile
| | - Kelli K Mullane
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093-0202, USA
| | - Roger A Chastain
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093-0202, USA
| | - A Aristides Yayanos
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093-0202, USA
| | - Masataka Kusube
- Department of Material Science, National Institute of Technology, Wakayama College, 77 Noshima, Nada-cho, Gobo, Wakayama, 644-0023, Japan
| | - Barbara A Methé
- Center for Microbiome and Medicine, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Douglas H Bartlett
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093-0202, USA.
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16
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Ogawa T, Hirose K, Yusuf Y, Kawamoto J, Kurihara T. Bioconversion From Docosahexaenoic Acid to Eicosapentaenoic Acid in the Marine Bacterium Shewanella livingstonensis Ac10. Front Microbiol 2020; 11:1104. [PMID: 32528457 PMCID: PMC7264947 DOI: 10.3389/fmicb.2020.01104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 05/04/2020] [Indexed: 11/13/2022] Open
Abstract
Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which belong to the same class of long chain ω-3 polyunsaturated fatty acids (PUFAs), are present in marine γ-proteobacteria. In contrast to their de novo biosynthesis that has been intensively studied, their metabolic fates remain largely unknown. Detailed information regarding bacterial ω-3 PUFA metabolism would be beneficial for understanding the physiological roles of EPA/DHA as well as the industrial production of EPA, DHA, and other PUFAs. Our previous studies revealed that the EPA-producing marine bacterium Shewanella livingstonensis Ac10 produces EPA from exogenous DHA independently of de novo EPA biosynthesis, indicating the presence of an unidentified metabolic pathway that converts DHA into EPA. In this study, we attempted to reveal the molecular basis for the bioconversion through both in vivo and in vitro analyses. Mutagenesis experiments showed that the gene disruption of fadH, which encodes an auxiliary β-oxidation enzyme 2,4-dienoyl-CoA reductase, impaired EPA production under DHA-supplemented conditions, and the estimated conversion rate decreased by 86% compared to that of the parent strain. We also found that the recombinant FadH had reductase activity toward the 2,4-dienoyl-CoA derivative of DHA, whereas the intermediate did not undergo β-oxidation in the absence of the FadH protein. These results indicate that a typical β-oxidation pathway is responsible for the conversion. Furthermore, we assessed whether DHA can act as a substitute for EPA by using an EPA-less and conversion-deficient mutant. The cold-sensitive phenotype of the mutant, which is caused by the lack of EPA, was suppressed by supplementation with EPA, whereas the DHA-supplementation suppressed it to a lesser extent. Therefore, DHA can partly substitute for, but is not biologically equivalent to, EPA in S. livingstonensis Ac10.
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Affiliation(s)
- Takuya Ogawa
- Molecular Microbial Science, Institute for Chemical Research, Kyoto University, Kyoto, Japan
| | - Kazuki Hirose
- Molecular Microbial Science, Institute for Chemical Research, Kyoto University, Kyoto, Japan
| | - Yustina Yusuf
- Molecular Microbial Science, Institute for Chemical Research, Kyoto University, Kyoto, Japan
| | - Jun Kawamoto
- Molecular Microbial Science, Institute for Chemical Research, Kyoto University, Kyoto, Japan
| | - Tatsuo Kurihara
- Molecular Microbial Science, Institute for Chemical Research, Kyoto University, Kyoto, Japan
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17
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Hassan N, Anesio AM, Rafiq M, Holtvoeth J, Bull I, Haleem A, Shah AA, Hasan F. Temperature Driven Membrane Lipid Adaptation in Glacial Psychrophilic Bacteria. Front Microbiol 2020; 11:824. [PMID: 32477293 PMCID: PMC7240044 DOI: 10.3389/fmicb.2020.00824] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 04/07/2020] [Indexed: 11/30/2022] Open
Abstract
Bacteria inhabiting non-polar glaciers are exposed to large variations in temperature, which significantly affects the fluidity of bacterial cell membranes. In order to maintain normal functions of the cell membranes, psychrophilic bacteria adapt by changing the composition of cell membrane fatty acids. However, information on the exact pattern of cell membrane adaptability in non-polar low-temperature habitats is scarce. In the present study, 42 bacterial strains were isolated from the Ghulmet, Ghulkin, and Hopar glaciers of the Hunza Valley in the Karakoram Mountain Range, Pakistan and their cell membrane fatty acid distributions studied, using gas chromatography/mass spectrometry (GC-MS) for the analysis of fatty acid methyl esters (FAMEs) liberated by acid-catalyzed methanolysis. Furthermore, Gram-negative and Gram-positive groups were grown under different temperature settings (5, 15, 25, and 35°C) in order to determine the effect of temperature on cell membrane (CM) fatty acid distribution. The analyses identified the major groups of cell membrane fatty acids (FA) as straight-chain monounsaturated fatty acids (n-MUFAs) and branched fatty acids (br-FAs), accounting for more than 70% of the fatty acids analyzed. The distribution of br-FAs and n-FAs in bacterial cell membranes was significantly affected by temperature, with the level of br-FAs decreasing relative to n-FAs with increasing temperature. Notably, the production of polyunsaturated fatty acids (PUFAs) was only seen at lower temperatures. This study contributes to understanding, for the first time, the role of br-FAs in the maintenance of cell membrane fluidity of bacteria inhabiting non-polar habitats.
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Affiliation(s)
- Noor Hassan
- Applied Environmental and Geomicrobiology Laboratory, Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
- Bristol Glaciology Centre, School of Geographical Sciences, Faculty of Science, University of Bristol, Bristol, United Kingdom
| | | | - Muhammad Rafiq
- Applied Environmental and Geomicrobiology Laboratory, Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
- Bristol Glaciology Centre, School of Geographical Sciences, Faculty of Science, University of Bristol, Bristol, United Kingdom
- Department of Microbiology, Balochistan University of Information Technology, Engineering and Management Sciences, Quetta, Pakistan
| | - Jens Holtvoeth
- Organic Geochemistry Unit, School of Chemistry, Cantock’s Close, University of Bristol, Bristol, United Kingdom
| | - Ian Bull
- Organic Geochemistry Unit, School of Chemistry, Cantock’s Close, University of Bristol, Bristol, United Kingdom
| | - Abdul Haleem
- Applied Environmental and Geomicrobiology Laboratory, Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Aamer Ali Shah
- Applied Environmental and Geomicrobiology Laboratory, Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Fariha Hasan
- Applied Environmental and Geomicrobiology Laboratory, Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
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18
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Estupiñán M, Hernández I, Saitua E, Bilbao ME, Mendibil I, Ferrer J, Alonso-Sáez L. Novel Vibrio spp. Strains Producing Omega-3 Fatty Acids Isolated from Coastal Seawater. Mar Drugs 2020; 18:E99. [PMID: 32024040 PMCID: PMC7074563 DOI: 10.3390/md18020099] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/27/2020] [Accepted: 01/30/2020] [Indexed: 12/26/2022] Open
Abstract
Omega-3 long-chain polyunsaturated fatty acids (LC-PUFAs), such as eicosapentaenoic acid (EPA) (20:5n-3) and docosahexaenoic acid (DHA) (22:6n-3), are considered essential for human health. Microorganisms are the primary producers of omega-3 fatty acids in marine ecosystems, representing a sustainable source of these lipids, as an alternative to the fish industry. Some marine bacteria can produce LC-PUFAs de novo via the Polyunsaturated Fatty Acid (Pfa) synthase/ Polyketide Synthase (PKS) pathway, which does not require desaturation and elongation of saturated fatty acids. Cultivation-independent surveys have revealed that the diversity of microorganisms harboring a molecular marker of the pfa gene cluster (i.e., pfaA-KS domain) is high and their potential distribution in marine systems is widespread, from surface seawater to sediments. However, the isolation of PUFA producers from marine waters has been typically restricted to deep or cold environments. Here, we report a phenotypic and genotypic screening for the identification of omega-3 fatty acid producers in free-living bacterial strains isolated from 5, 500, and 1000 m deep coastal seawater from the Bay of Biscay (Spain). We further measured EPA production in pelagic Vibrio sp. strains collected at the three different depths. Vibrio sp. EPA-producers and non-producers were simultaneously isolated from the same water samples and shared a high percentage of identity in their 16S rRNA genes, supporting the view that the pfa gene cluster can be horizontally transferred. Within a cluster of EPA-producers, we found intraspecific variation in the levels of EPA synthesis for isolates harboring different genetic variants of the pfaA-KS domain. The maximum production of EPA was found in a Vibrio sp. strain isolated from a 1000 m depth (average 4.29% ± 1.07 of total fatty acids at 10 °C, without any optimization of culturing conditions).
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Affiliation(s)
- Mónica Estupiñán
- AZTI, Marine Research Division, Txatxarramendi Irla s/n, 48395 Sukarrieta, Spain; (M.E.); (M.E.B.); (I.M.)
| | - Igor Hernández
- AZTI, Food Research Division, Astondo Bidea, Building 609, 48160 Derio, Spain; (I.H.); (E.S.); (J.F.)
| | - Eduardo Saitua
- AZTI, Food Research Division, Astondo Bidea, Building 609, 48160 Derio, Spain; (I.H.); (E.S.); (J.F.)
| | - M. Elisabete Bilbao
- AZTI, Marine Research Division, Txatxarramendi Irla s/n, 48395 Sukarrieta, Spain; (M.E.); (M.E.B.); (I.M.)
| | - Iñaki Mendibil
- AZTI, Marine Research Division, Txatxarramendi Irla s/n, 48395 Sukarrieta, Spain; (M.E.); (M.E.B.); (I.M.)
| | - Jorge Ferrer
- AZTI, Food Research Division, Astondo Bidea, Building 609, 48160 Derio, Spain; (I.H.); (E.S.); (J.F.)
| | - Laura Alonso-Sáez
- AZTI, Marine Research Division, Txatxarramendi Irla s/n, 48395 Sukarrieta, Spain; (M.E.); (M.E.B.); (I.M.)
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19
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Complete Genome Sequence of the Deep-Sea Bacterium Moritella marina MP-1 (ATCC 15381). Microbiol Resour Announc 2020; 9:9/4/e01321-19. [PMID: 31974151 PMCID: PMC6979300 DOI: 10.1128/mra.01321-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Here, the complete assembly of the
Moritella marina
MP-1 (ATCC 15381) genome, combining Illumina and long Nanopore reads, is presented. The gapless assembly consists of a 4.7-Mb circular chromosome and a 26-kb plasmid, with a G+C content of 40.7%, and will assist in further studies of the molecular pathways in this biotechnologically significant organism.
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20
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Picoplankton Distribution and Activity in the Deep Waters of the Southern Adriatic Sea. WATER 2019. [DOI: 10.3390/w11081655] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Southern Adriatic (Eastern Mediterranean Sea) is a region strongly dominated by large-scale oceanographic processes and local open-ocean dense water formation. In this study, picoplankton biomass, distribution, and activity were examined during two oceanographic cruises and analyzed in relation to environmental parameters and hydrographic conditions comparing pre and post-winter phases (December 2015, April 2016). Picoplankton density with the domination of autotrophic biomasses was higher in the pre-winter phase when significant amounts of picoaoutotrophs were also found in the meso-and bathy-pelagic layers, while Synechococcus dominated the picoautotrophic group. Higher values of bacterial production and domination of High Nucleic Acid content bacteria (HNA bacteria) were found in deep waters, especially during the post-winter phase, suggesting that bacteria can have an active role in the deep-sea environment. Aerobic anoxygenic phototrophic bacteria accounted for a small proportion of total heterotrophic bacteria but contributed up to 4% of bacterial carbon content. Changes in the picoplankton community were mainly driven by nutrient availability, heterotrophic nanoflagellates abundance, and water mass movements and mixing. Our results suggest that autotrophic and heterotrophic members of the picoplankton community are an important carbon source in the food web in the deep-sea, as well as in the epipelagic layer. Besides, viral lysis may affect the activity of the picoplankton community and enrich the water column with dissolved organic carbon.
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Scoma A, Garrido-Amador P, Nielsen SD, Røy H, Kjeldsen KU. The Polyextremophilic Bacterium Clostridium paradoxum Attains Piezophilic Traits by Modulating Its Energy Metabolism and Cell Membrane Composition. Appl Environ Microbiol 2019; 85:e00802-19. [PMID: 31126939 PMCID: PMC6643245 DOI: 10.1128/aem.00802-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 05/13/2019] [Indexed: 11/20/2022] Open
Abstract
In polyextremophiles, i.e., microorganisms growing preferentially under multiple extremes, synergistic effects may allow growth when application of the same extremes alone would not. High hydrostatic pressure (HP) is rarely considered in studies of polyextremophiles, and its role in potentially enhancing tolerance to other extremes remains unclear. Here, we investigated the HP-temperature response in Clostridium paradoxum, a haloalkaliphilic moderately thermophilic endospore-forming bacterium, in the range of 50 to 70°C and 0.1 to 30 MPa. At ambient pressure, growth limits were extended from the previously reported 63°C to 70°C, defining C. paradoxum as an actual thermophile. Concomitant application of high HP and temperature compared to standard conditions (i.e., ambient pressure and 50°C) remarkably enhanced growth, with an optimum growth rate observed at 22 MPa and 60°C. HP distinctively defined C. paradoxum physiology, as at 22 MPa biomass, production increased by 75% and the release of fermentation products per cell decreased by >50% compared to ambient pressure. This metabolic modulation was apparently linked to an energy-preserving mechanism triggered by HP, involving a shift toward pyruvate as the preferred energy and carbon source. High HPs decreased cell damage, as determined by Syto9 and propidium iodide staining, despite no organic solute being accumulated intracellularly. A distinct reduction in carbon chain length of phospholipid fatty acids (PLFAs) and an increase in the amount of branched-chain PLFAs occurred at high HP. Our results describe a multifaceted, cause-and-effect relationship between HP and cell metabolism, stressing the importance of applying HP to define the boundaries for life under polyextreme conditions.IMPORTANCE Hydrostatic pressure (HP) is a fundamental parameter influencing biochemical reactions and cell physiology; however, it is less frequently applied than other factors, such as pH, temperature, and salinity, when studying polyextremophilic microorganisms. In particular, how HP affects microbial tolerance to other and multiple extremes remains unclear. Here, we show that under polyextreme conditions of high pH and temperature, Clostridium paradoxum demonstrates a moderately piezophilic nature as cultures grow to highest cell densities and most efficiently at a specific combination of temperature and HP. Our results highlight the importance of considering HP when exploring microbial physiology under extreme conditions and thus have implications for defining the limits for microbial life in nature and for optimizing industrial bioprocesses occurring under multiple extremes.
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Affiliation(s)
- Alberto Scoma
- Department of Bioscience, Section of Microbiology, Aarhus University, Aarhus, Denmark
| | - Paloma Garrido-Amador
- Department of Bioscience, Section of Microbiology, Aarhus University, Aarhus, Denmark
| | | | - Hans Røy
- Department of Bioscience, Section of Microbiology, Aarhus University, Aarhus, Denmark
| | - Kasper Urup Kjeldsen
- Department of Bioscience, Section of Microbiology, Aarhus University, Aarhus, Denmark
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Biological composition and microbial dynamics of sinking particulate organic matter at abyssal depths in the oligotrophic open ocean. Proc Natl Acad Sci U S A 2019; 116:11824-11832. [PMID: 31127042 PMCID: PMC6575173 DOI: 10.1073/pnas.1903080116] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Sinking particles composed of both organic and inorganic material feed the deep-sea ecosystem and contribute centrally to ocean carbon sequestration. Despite their importance, little is known about the biological composition of sinking particles reaching the deep sea. Time-series analyses of sinking particles unexpectedly revealed bacterial assemblages that were simple and homogeneous over time. Particle-associated eukaryote assemblages, however, were more variable and complex. Several modes of export were observed, including summer inputs from the surface, more stochastic export of surface-derived protists and animals, and contributions from midwater animals and deep-sea bacteria. In summary, sinking particles exhibited temporally variable, heterogeneous biological sources and activities that reflected their important roles in the downward transport and transformation of organic matter in the deep sea. Sinking particles are a critical conduit for the export of organic material from surface waters to the deep ocean. Despite their importance in oceanic carbon cycling and export, little is known about the biotic composition, origins, and variability of sinking particles reaching abyssal depths. Here, we analyzed particle-associated nucleic acids captured and preserved in sediment traps at 4,000-m depth in the North Pacific Subtropical Gyre. Over the 9-month time-series, Bacteria dominated both the rRNA-gene and rRNA pools, followed by eukaryotes (protists and animals) and trace amounts of Archaea. Deep-sea piezophile-like Gammaproteobacteria, along with Epsilonproteobacteria, comprised >80% of the bacterial inventory. Protists (mostly Rhizaria, Syndinales, and ciliates) and metazoa (predominantly pelagic mollusks and cnidarians) were the most common sinking particle-associated eukaryotes. Some near-surface water-derived eukaryotes, especially Foraminifera, Radiolaria, and pteropods, varied greatly in their abundance patterns, presumably due to sporadic export events. The dominance of piezophile-like Gammaproteobacteria and Epsilonproteobacteria, along with the prevalence of their nitrogen cycling-associated gene transcripts, suggested a central role for these bacteria in the mineralization and biogeochemical transformation of sinking particulate organic matter in the deep ocean. Our data also reflected several different modes of particle export dynamics, including summer export, more stochastic inputs from the upper water column by protists and pteropods, and contributions from sinking mid- and deep-water organisms. In total, our observations revealed the variable and heterogeneous biological origins and microbial activities of sinking particles that connect their downward transport, transformation, and degradation to deep-sea biogeochemical processes.
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Parzanini C, Parrish CC, Hamel JF, Mercier A. Functional diversity and nutritional content in a deep-sea faunal assemblage through total lipid, lipid class, and fatty acid analyses. PLoS One 2018; 13:e0207395. [PMID: 30419073 PMCID: PMC6231680 DOI: 10.1371/journal.pone.0207395] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 10/30/2018] [Indexed: 01/13/2023] Open
Abstract
Lipids are key compounds in marine ecosystems being involved in organism growth, reproduction, and survival. Despite their biological significance and ease of measurement, the use of lipids in deep-sea studies is limited, as is our understanding of energy and nutrient flows in the deep ocean. Here, a comprehensive analysis of total lipid content, and lipid class and fatty acid composition, was used to explore functional diversity and nutritional content within a deep-sea faunal assemblage comprising 139 species from 8 phyla, including the Chordata, Arthropoda, and Cnidaria. A wide range of total lipid content and lipid class composition suggested a diversified set of energy allocation strategies across taxa. Overall, phospholipid was the dominant lipid class. While triacylglycerol was present in most taxa as the main form of energy storage, a few crustaceans, fish, jellyfishes, and corals had higher levels of wax esters/steryl esters instead. Type and amount of energy reserves may reflect dietary sources and environmental conditions for certain deep-sea taxa. Conversely, the composition of fatty acids was less diverse than that of lipid class composition, and large proportions of unsaturated fatty acids were detected, consistent with the growing literature on cold-water species. In addition, levels of unsaturation increased with depth, likely suggesting an adaptive strategy to maintain normal membrane structure and function in species found in deeper waters. Although proportions of n-3 fatty acids were high across all phyla, representatives of the Chordata and Arthropoda were the main reservoirs of these essential nutrients, thus suggesting health benefits to their consumers.
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Affiliation(s)
- Camilla Parzanini
- Department of Ocean Sciences, Memorial University, St. John’s, NL, Canada
| | | | - Jean-François Hamel
- Society for Exploration and Valuing of the Environment (SEVE), Portugal Cove-St. Philips, NL, Canada
| | - Annie Mercier
- Department of Ocean Sciences, Memorial University, St. John’s, NL, Canada
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de Carvalho CCCR, Caramujo MJ. The Various Roles of Fatty Acids. Molecules 2018; 23:molecules23102583. [PMID: 30304860 PMCID: PMC6222795 DOI: 10.3390/molecules23102583] [Citation(s) in RCA: 349] [Impact Index Per Article: 58.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 10/01/2018] [Accepted: 10/06/2018] [Indexed: 12/31/2022] Open
Abstract
Lipids comprise a large group of chemically heterogeneous compounds. The majority have fatty acids (FA) as part of their structure, making these compounds suitable tools to examine processes raging from cellular to macroscopic levels of organization. Among the multiple roles of FA, they have structural functions as constituents of phospholipids which are the "building blocks" of cell membranes; as part of neutral lipids FA serve as storage materials in cells; and FA derivatives are involved in cell signalling. Studies on FA and their metabolism are important in numerous research fields, including biology, bacteriology, ecology, human nutrition and health. Specific FA and their ratios in cellular membranes may be used as biomarkers to enable the identification of organisms, to study adaptation of bacterial cells to toxic compounds and environmental conditions and to disclose food web connections. In this review, we discuss the various roles of FA in prokaryotes and eukaryotes and highlight the application of FA analysis to elucidate ecological mechanisms. We briefly describe FA synthesis; analyse the role of FA as modulators of cell membrane properties and FA ability to store and supply energy to cells; and inspect the role of polyunsaturated FA (PUFA) and the suitability of using FA as biomarkers of organisms.
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Affiliation(s)
- Carla C C R de Carvalho
- Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
| | - Maria José Caramujo
- Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Edifício C2-5º Piso, 1749-016 Lisboa, Portugal.
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Cell-Free Expression of Unnatural Amino Acid Incorporated Aquaporin SS9 with Improved Separation Performance in Biomimetic Membranes. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3560894. [PMID: 30363687 PMCID: PMC6181008 DOI: 10.1155/2018/3560894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 07/29/2018] [Accepted: 09/06/2018] [Indexed: 11/17/2022]
Abstract
Aquaporins (AQPs) are widely applied in biomimetic membranes for water recycling and desalination. In this study, a novel aquaporin was isolated from Photobacterium profundum SS9 (AQP SS9), which showed high water permeability and potential for practical water purification applications. To improve the stability of the AQP SS9 embedded biomimetic membranes, a modified AQP SS9 was obtained by incorporation of an unnatural amino acid (p-propargyloxyphenylalanine, pPpa) (P-AQP SS9) in vitro using a mutated Methanocaldococcus jannaschii tyrosyl-tRNA synthetase (TyrRS) and the cell-free expression system. The modified AQP SS9 can covalently link with phospholipids and hence significantly improve the stability of biomimetic membranes. The concentration of Mg2+ and fusion expression with signal peptides were evaluated to enhance the expression level of P-AQP SS9, resulting in a highest yield of 49 mg/L. The modified AQP SS9 was then reconstituted into DOPC liposomes and analyzed by a stopped-flow spectrophotometer. The obtained water permeability coefficient (Pf) of 7.46×10−4 m/s was 5.7 times higher than that of proteoliposomes with the wild-type AQP SS9 (Pf=1.31×10−4 m/s) and 12.1 times higher than that of the DOPC liposomes (Pf=6.15×10−5m/s). This study demonstrates the development of a cell-free system for the expression of membrane proteins with much higher stability and the potential application of the modified aquaporins for water filtration.
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Polyunsaturated fatty acids in marine bacteria and strategies to enhance their production. Appl Microbiol Biotechnol 2018; 102:5811-5826. [PMID: 29749565 DOI: 10.1007/s00253-018-9063-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 04/26/2018] [Accepted: 04/30/2018] [Indexed: 10/16/2022]
Abstract
Polyunsaturated fatty acids (PUFAs) play an important role in human diet. Despite the wide-ranging importance and benefits from heart health to brain functions, humans and mammals cannot synthesize PUFAs de novo. The primary sources of PUFA are fish and plants. Due to the increasing concerns associated with food security as well as issues of environmental contaminants in fish oil, there has been considerable interest in the production of polyunsaturated fatty acids from alternative resources which are more sustainable, safer, and economical. For instance, marine bacteria, particularly the genus of Shewanella, Photobacterium, Colwellia, Moritella, Psychromonas, Vibrio, and Alteromonas, are found to be one among the major microbial producers of polyunsaturated fatty acids. Recent developments in the area with a focus on the production of polyunsaturated fatty acids from marine bacteria as well as the metabolic engineering strategies for the improvement of PUFA production are discussed.
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Miranda AF, Liu Z, Rochfort S, Mouradov A. Lipid production in aquatic plant Azolla at vegetative and reproductive stages and in response to abiotic stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 124:117-125. [PMID: 29366971 DOI: 10.1016/j.plaphy.2018.01.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/13/2018] [Accepted: 01/15/2018] [Indexed: 06/07/2023]
Abstract
The aquatic plant Azolla became increasingly popular as bioenergy feedstock because of its high growth rate, production of biomass with high levels of biofuel-producing molecules and ability to grow on marginal lands. In this study, we analysed the contribution of all organs of Azolla to the total yield of lipids at vegetative and reproductive stages and in response to stress. Triacylglycerol-containing lipid droplets were detected in all (vegetative and reproductive) organs with the highest level in the male microsporocarps and microspores. As a result, significantly higher total yields of lipids were detected in Azolla filiculoides and Azolla pinnata at the reproductive stage. Starving changed the yield and composition of the fatty acid as a result of re-direction of carbon flow from fatty acid to anthocyanin pathways. The composition of lipids, in regard the length and degree of unsaturation of fatty acids, in Azolla meets most of the important requirements for biodiesel standards. The ability of Azolla to grow on wastewaters, along with their high productivity rate, makes it an attractive feedstock for the production of biofuels.
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Affiliation(s)
- Ana F Miranda
- School of Sciences, RMIT University, Melbourne, VIC, Australia.
| | - Zhiqian Liu
- AgriBio, Centre for AgriBioscience, La Trobe University, Bundoora, VIC 3083, Australia.
| | - Simone Rochfort
- AgriBio, Centre for AgriBioscience, La Trobe University, Bundoora, VIC 3083, Australia.
| | - Aidyn Mouradov
- School of Sciences, RMIT University, Melbourne, VIC, Australia.
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Allemann MN, Allen EE. Characterization and Application of Marine Microbial Omega-3 Polyunsaturated Fatty Acid Synthesis. Methods Enzymol 2018; 605:3-32. [DOI: 10.1016/bs.mie.2018.02.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Zhang J, Burgess JG. Enhanced eicosapentaenoic acid production by a new deep-sea marine bacterium Shewanella electrodiphila MAR441T. PLoS One 2017; 12:e0188081. [PMID: 29176835 PMCID: PMC5703452 DOI: 10.1371/journal.pone.0188081] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 10/31/2017] [Indexed: 02/05/2023] Open
Abstract
Omega-3 fatty acids are products of secondary metabolism, essential for growth and important for human health. Although there are numerous reports of bacterial production of omega-3 fatty acids, less information is available on the biotechnological production of these compounds from bacteria. The production of eicosapentaenoic acid (EPA, 20:5ω3) by a new species of marine bacteria Shewanella electrodiphila MAR441T was investigated under different fermentation conditions. This strain produced a high percentage (up to 26%) of total fatty acids and high yields (mg / g of biomass) of EPA at or below the optimal growth temperature. At higher growth temperatures these values decreased greatly. The amount of EPA produced was affected by the carbon source, which also influenced fatty acid composition. This strain required Na+ for growth and EPA synthesis and cells harvested at late exponential or early stationary phase had a higher EPA content. Both the highest amounts (20 mg g-1) and highest percent EPA content (18%) occurred with growth on L-proline and (NH4)2SO4. The addition of cerulenin further enhanced EPA production to 30 mg g-1. Chemical mutagenesis using NTG allowed the isolation of mutants with improved levels of EPA content (from 9.7 to 15.8 mg g-1) when grown at 15°C. Thus, the yields of EPA could be substantially enhanced without the need for recombinant DNA technology, often a commercial requirement for food supplement manufacture.
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Affiliation(s)
- Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratory, Exeter, United Kingdom
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - J. Grant Burgess
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
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Kusube M, Kyaw TS, Tanikawa K, Chastain RA, Hardy KM, Cameron J, Bartlett DH. Colwellia marinimaniae sp. nov., a hyperpiezophilic species isolated from an amphipod within the Challenger Deep, Mariana Trench. Int J Syst Evol Microbiol 2017; 67:824-831. [DOI: 10.1099/ijsem.0.001671] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Masataka Kusube
- Department of Material Science, National Institute of Technology, Wakayama College, 77 Noshima, Nada-cho, Gobo, Wakayama 644-0023, Japan
| | - Than S. Kyaw
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0202, USA
| | - Kumiko Tanikawa
- Department of Material Science, National Institute of Technology, Wakayama College, 77 Noshima, Nada-cho, Gobo, Wakayama 644-0023, Japan
| | - Roger A. Chastain
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0202, USA
| | - Kevin M. Hardy
- Global Ocean Dynamics. Global Ocean Design, 7955 Silverton Ave., Suite 1208, San Diego, CA 92126, USA
| | - James Cameron
- Avatar Alliance Foundation, 16255 Ventura Blvd. Suite 525, Encino, CA 91436, USA
| | - Douglas H. Bartlett
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0202, USA
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Padmanaban VP, Verma P, Venkatabaskaran S, Keppayan T, Gopal D, Sekar AK, Ramalingam K. Antimicrobial potential and taxonomic investigation of piezotolerant Streptomyces sp. NIOT-Ch-40 isolated from deep-sea sediment. World J Microbiol Biotechnol 2017; 33:27. [DOI: 10.1007/s11274-016-2193-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 12/20/2016] [Indexed: 11/28/2022]
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Michoud G, Jebbar M. High hydrostatic pressure adaptive strategies in an obligate piezophile Pyrococcus yayanosii. Sci Rep 2016; 6:27289. [PMID: 27250364 PMCID: PMC4890121 DOI: 10.1038/srep27289] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 05/14/2016] [Indexed: 02/06/2023] Open
Abstract
Pyrococcus yayanosii CH1, as the first and only obligate piezophilic hyperthermophilic microorganism discovered to date, extends the physical and chemical limits of life on Earth. It was isolated from the Ashadze hydrothermal vent at 4,100 m depth. Multi-omics analyses were performed to study the mechanisms used by the cell to cope with high hydrostatic pressure variations. In silico analyses showed that the P. yayanosii genome is highly adapted to its harsh environment, with a loss of aromatic amino acid biosynthesis pathways and the high constitutive expression of the energy metabolism compared with other non-obligate piezophilic Pyrococcus species. Differential proteomics and transcriptomics analyses identified key hydrostatic pressure-responsive genes involved in translation, chemotaxis, energy metabolism (hydrogenases and formate metabolism) and Clustered Regularly Interspaced Short Palindromic Repeats sequences associated with Cellular apoptosis susceptibility proteins.
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Affiliation(s)
- Grégoire Michoud
- Univ Brest, CNRS, Ifremer, UMR 6197-Laboratoire de Microbiologie des Environnements Extrêmes (LM2E), Institut Universitaire Européen de la Mer (IUEM), rue Dumont d'Urville, 29 280 Plouzané, France
| | - Mohamed Jebbar
- Univ Brest, CNRS, Ifremer, UMR 6197-Laboratoire de Microbiologie des Environnements Extrêmes (LM2E), Institut Universitaire Européen de la Mer (IUEM), rue Dumont d'Urville, 29 280 Plouzané, France
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Zhang L, Wang X, Yu M, Qiao Y, Zhang XH. Genomic analysis of Luteimonas abyssi XH031(T): insights into its adaption to the subseafloor environment of South Pacific Gyre and ecological role in biogeochemical cycle. BMC Genomics 2015; 16:1092. [PMID: 26690083 PMCID: PMC4687298 DOI: 10.1186/s12864-015-2326-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 12/15/2015] [Indexed: 01/22/2023] Open
Abstract
Background Luteimonas abyssi XH031T, which was previously isolated from subseafloor environment of the South Pacific Gyre (SPG), was an aerobic, gram-negative bacterium, and was identified to be a novel species of the genus Luteimonas in the family of Xanthomonadaceae. The nutrients utilization and metabolic mechanisms of XH031T indicate its plasticity. In view of the above characteristics, its genome was sequenced, and an in-depth analysis of the XH031T genome was performed to elucidate its adaption to extreme ecological environment. Results Various macromolecules including polysaccharide, protein, lipid and DNA could be degraded at low temperature by XH031T under laboratory conditions, and its degradation abilities to starch, gelatin and casein were considerably strong. Genome sequence analysis indicated that XH031T possesses extensive enzyme-encoding genes compared with four other Luteimonas strains. In addition, intricate systems (such as two-component regulatory systems, secretion systems, etc.), which are often used by bacteria to modulate the interactions of bacteria with their environments, were predicted in the genome of XH031T. Genes encoding a choline-glycine betaine transporter and 99 extracellular peptidases featured with halophilicity were predicted in the genome, which might help the bacterium to adapt to the salty marine environment. Moreover, there were many gene clusters in the genome encoding ATP-binding cassette superfamily transporters, major facilitator superfamily transporters and cytochrome P450s that might function in the process of various substrate transportation and metabolisms. Furthermore, drug resistance genes harbored in the genome might signify that XH031T has evolved hereditary adaptation to toxic environment. Finally, the annotation of metabolic pathways of the elements (such as carbon, nitrogen, sulfur, phosphor and iron) in the genome elucidated the degradation of organic matter in the deep sediment of the SPG. Conclusions The genome analysis showed that XH031T had genetic advantages to adapt to subseafloor environment. The material metabolism manifests that the strain may play an important ecological role in the biogeochemical cycle of the SPG, and various cold-adapted extracelluar enzymes produced by the strain may have significant value in application. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2326-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Li Zhang
- College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China. .,College of Life Science, Qingdao Agriculture University, Qingdao, 266109, China.
| | - Xiaolei Wang
- College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.
| | - Min Yu
- College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.
| | - Yanlu Qiao
- College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.
| | - Xiao-Hua Zhang
- College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.
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The Microbiota of Freshwater Fish and Freshwater Niches Contain Omega-3 Fatty Acid-Producing Shewanella Species. Appl Environ Microbiol 2015; 82:218-31. [PMID: 26497452 DOI: 10.1128/aem.02266-15] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/15/2015] [Indexed: 11/20/2022] Open
Abstract
Approximately 30 years ago, it was discovered that free-living bacteria isolated from cold ocean depths could produce polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) (20:5n-3) or docosahexaenoic acid (DHA) (22:6n-3), two PUFA essential for human health. Numerous laboratories have also discovered that EPA- and/or DHA-producing bacteria, many of them members of the Shewanella genus, could be isolated from the intestinal tracts of omega-3 fatty acid-rich marine fish. If bacteria contribute omega-3 fatty acids to the host fish in general or if they assist some bacterial species in adaptation to cold, then cold freshwater fish or habitats should also harbor these producers. Thus, we undertook a study to see if these niches also contained omega-3 fatty acid producers. We were successful in isolating and characterizing unique EPA-producing strains of Shewanella from three strictly freshwater native fish species, i.e., lake whitefish (Coregonus clupeaformis), lean lake trout (Salvelinus namaycush), and walleye (Sander vitreus), and from two other freshwater nonnative fish, i.e., coho salmon (Oncorhynchus kisutch) and seeforellen brown trout (Salmo trutta). We were also able to isolate four unique free-living strains of EPA-producing Shewanella from freshwater habitats. Phylogenetic and phenotypic analyses suggest that one producer is clearly a member of the Shewanella morhuae species and another is sister to members of the marine PUFA-producing Shewanella baltica species. However, the remaining isolates have more ambiguous relationships, sharing a common ancestor with non-PUFA-producing Shewanella putrefaciens isolates rather than marine S. baltica isolates despite having a phenotype more consistent with S. baltica strains.
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Lipid Adaptation of Shrimp Rimicaris exoculata in Hydrothermal Vent. Lipids 2015; 50:1233-42. [DOI: 10.1007/s11745-015-4081-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 09/23/2015] [Indexed: 02/07/2023]
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Fichtel K, Logemann J, Fichtel J, Rullkötter J, Cypionka H, Engelen B. Temperature and pressure adaptation of a sulfate reducer from the deep subsurface. Front Microbiol 2015; 6:1078. [PMID: 26500624 PMCID: PMC4594026 DOI: 10.3389/fmicb.2015.01078] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 09/21/2015] [Indexed: 11/13/2022] Open
Abstract
Microbial life in deep marine subsurface faces increasing temperatures and hydrostatic pressure with depth. In this study, we have examined growth characteristics and temperature-related adaptation of the Desulfovibrio indonesiensis strain P23 to the in situ pressure of 30 MPa. The strain originates from the deep subsurface of the eastern flank of the Juan de Fuca Ridge (IODP Site U1301). The organism was isolated at 20°C and atmospheric pressure from ~61°C-warm sediments approximately 5 m above the sediment-basement interface. In comparison to standard laboratory conditions (20°C and 0.1 MPa), faster growth was recorded when incubated at in situ pressure and high temperature (45°C), while cell filamentation was induced by further compression. The maximum growth temperature shifted from 48°C at atmospheric pressure to 50°C under high-pressure conditions. Complementary cellular lipid analyses revealed a two-step response of membrane viscosity to increasing temperature with an exchange of unsaturated by saturated fatty acids and subsequent change from branched to unbranched alkyl moieties. While temperature had a stronger effect on the degree of fatty acid saturation and restructuring of main phospholipids, pressure mainly affected branching and length of side chains. The simultaneous decrease of temperature and pressure to ambient laboratory conditions allowed the cultivation of our moderately thermophilic strain. This may in turn be one key to a successful isolation of microorganisms from the deep subsurface adapted to high temperature and pressure.
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Affiliation(s)
- Katja Fichtel
- Paleomicrobiology Group, Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, OldenburgGermany
| | - Jörn Logemann
- Organic Geochemistry Group, Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, OldenburgGermany
| | - Jörg Fichtel
- Organic Geochemistry Group, Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, OldenburgGermany
| | - Jürgen Rullkötter
- Organic Geochemistry Group, Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, OldenburgGermany
| | - Heribert Cypionka
- Paleomicrobiology Group, Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, OldenburgGermany
| | - Bert Engelen
- Paleomicrobiology Group, Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, OldenburgGermany
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Zhang J, Burgess JG. Shewanella electrodiphila sp. nov., a psychrotolerant bacterium isolated from Mid-Atlantic Ridge deep-sea sediments. Int J Syst Evol Microbiol 2015; 65:2882-2889. [PMID: 25999594 DOI: 10.1099/ijs.0.000345] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Strains MAR441(T) and MAR445 were isolated from Mid-Atlantic Ridge sediments from a depth of 2734 m, and were found to belong to the genus Shewanella. The strains were rod-shaped, pigmented, non-motile and capable of anaerobic growth either by fermentation of carbohydrates or by anaerobic respiration. The strains utilized a variety of electron acceptors, including nitrate and ferric compounds, and could utilize peptone when grown anaerobically in a two-chambered microbial fuel cell, which used carbon cloth electrodes and delivered a stable power output of ,150-200 mW m(-2). The major fatty acids were typical of the genus Shewanella, with major components C13 : 0, iso-C13 : 0, iso-C15 : 0, C16 : 0, C16 : 1ω7c, C18 : 1ω7c and C20 : 5ω3 fatty acids. The DNA G+C content of strains MAR441(T) and MAR445 was 42.4 mol%. 16S rRNA gene sequence analysis indicated that strains MAR441(T) and MAR445 were most closely related to Shewanella olleyana (sequence similarities 97.9% to the type strain). DNA-DNA hybridization demonstrated only 15.6-37.2% relatedness between strain MAR441(T) and the type strains of related species of the genus Shewanella. Phenotypic characteristics confirmed that these isolates constituted a novel species of the genus Shewanella, for which the name Shewanella electrodiphila sp. nov. is proposed; the type strain is MAR441(T) (5ATCC BAA-2408(T) = DSM 24955(T)).
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Affiliation(s)
- Jinwei Zhang
- School of Marine Science and Technology, Newcastle University, Newcastle upon Tyne NE30 4PZ, UK
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
| | - J Grant Burgess
- School of Marine Science and Technology, Newcastle University, Newcastle upon Tyne NE30 4PZ, UK
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Wannicke N, Frindte K, Gust G, Liskow I, Wacker A, Meyer A, Grossart HP. Measuring bacterial activity and community composition at high hydrostatic pressure using a novel experimental approach: a pilot study. FEMS Microbiol Ecol 2015; 91:fiv036. [DOI: 10.1093/femsec/fiv036] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2015] [Indexed: 11/12/2022] Open
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Koopmans M, van Rijswijk P, Boschker HTS, Marco H, Martens D, Wijffels RH. Seasonal variation of Fatty acids and stable carbon isotopes in sponges as indicators for nutrition: biomarkers in sponges identified. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2015; 17:43-54. [PMID: 25107690 DOI: 10.1007/s10126-014-9594-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 07/18/2014] [Indexed: 06/03/2023]
Abstract
To get a better understanding of sponge feeding biology and efficiencies, the fatty acid (FA) composition and (13)C natural abundance of sponges and of suspended particulate matter (SPM) from surrounding seawater was studied in different seasons at three locations. Haliclona oculata and Haliclona xena from the Oosterschelde, the Netherlands, Halichondria panicea and H. xena from Lake Veere, the Netherlands, and Aplysina aerophoba and Dysidea avara from the Mediterranean, Spain, were studied. Several FA biomarkers for different algal groups, bacteria and sponge biomass were identified in all sponges. The FA concentration variation in sponges was related to changes in fatty acid concentration in SPM. Stable carbon isotopic ratios (δ(13)C) in sponge specific FAs showed very limited seasonal variation at all sites. Algal FAs in sponges were mainly acquired from the SPM through active filtration in all seasons. At the two sites in the Netherlands only in May (spring), the sponge specific FAs had similar δ(13)C ratios as algal FAs, suggesting that sponges were mainly growing during spring and probably summer. During autumn and winter, they were still actively filtering, but the food collected during this period had little effect on sponge δ(13)C values suggesting limited incorporation of filtered material into the sponge body. The sponge A. aerophoba relied mostly on the symbiotic bacteria. In conclusion, fatty acid composition in combination with stable carbon isotope analysis can be used to analyze the food source of sponges.
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Affiliation(s)
- Marieke Koopmans
- Department of Agrotechnology and Food Sciences, Bioprocess Engineering Group, Wageningen University, P.O. 8129, 6700 EV, Wageningen, The Netherlands,
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Abstract
Microbes produce a huge array of secondary metabolites endowed with important ecological functions. These molecules, which can be catalogued as natural products, have long been exploited in medical fields as antibiotics, anticancer and anti-infective agents. Recent years have seen considerable advances in elucidating natural-product biosynthesis and many drugs used today are natural products or natural-product derivatives. The major contribution to recent knowledge came from application of genomics to secondary metabolism and was facilitated by all relevant genes being organised in a contiguous DNA segment known as gene cluster. Clustering of genes regulating biosynthesis in bacteria is virtually universal. Modular gene clusters can be mixed and matched during evolution to generate structural diversity in natural products. Biosynthesis of many natural products requires the participation of complex molecular machines known as polyketide synthases and non-ribosomal peptide synthetases. Discovery of new evolutionary links between the polyketide synthase and fatty acid synthase pathways may help to understand the selective advantages that led to evolution of secondary-metabolite biosynthesis within bacteria. Secondary metabolites confer selective advantages, either as antibiotics or by providing a chemical language that allows communication among species, with other organisms and their environment. Herewith, we discuss these aspects focusing on the most clinically relevant bioactive molecules, the thiotemplated modular systems that include polyketide synthases, non-ribosomal peptide synthetases and fatty acid synthases. We begin by describing the evolutionary and physiological role of marine natural products, their structural/functional features, mechanisms of action and biosynthesis, then turn to genomic and metagenomic approaches, highlighting how the growing body of information on microbial natural products can be used to address fundamental problems in environmental evolution and biotechnology.
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Abstract
The deep biosphere is composed of very different biotopes located in the depth of the oceans, the ocean crust or the lithosphere. Although very different, deep biosphere biotopes share one common feature, high hydrostatic pressure. The deep biosphere is colonized by specific organisms, called piezophiles, that are able to grow under high hydrostatic pressure. Bacterial piezophiles are mainly psychrophiles belonging to five genera of γ-proteobacteria, Photobacterium, Shewanella, Colwellia, Psychromonas and Moritella, while piezophilic Archaea are mostly (hyper)thermophiles from the Thermococcales. None of these genera are specific for the deep biosphere. High pressure deeply impacts the activity of cells and cellular components, and reduces the activity of numerous key processes, eventually leading to cell death of piezosensitive organisms. Biochemical and genomic studies yield a fragmented view on the adaptive mechanisms in piezophiles. It is yet unclear whether piezophilic adaptation requires the modification of a few genes, or metabolic pathways, or a more profound reorganization of the genome, the fine tuning of gene expression to compensate the pressure-induced loss of activity of the proteins most affected by high pressure, or a stress-like physiological cell response. In contrast to what has been seen for thermophily or halophily, the adaptation to high pressure is diffuse in the genome and may concern only a small fraction of the genes.
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Identification of a novel type of polyunsaturated fatty acid synthase involved in arachidonic acid biosynthesis. FEBS Lett 2014; 588:4032-6. [PMID: 25263707 DOI: 10.1016/j.febslet.2014.09.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 08/28/2014] [Accepted: 09/16/2014] [Indexed: 01/09/2023]
Abstract
Arachidonic acid (ARA) is a polyunsaturated fatty acid (PUFA) and an essential component of membrane lipids. However, the PUFA synthase required for ARA biosynthesis has not been identified in any organism. To identify the PUFA synthase producing ARA, we determined the draft genome sequence of the marine bacterium Aureispira marina, which produces a high level of ARA, and found a gene cluster encoding a putative PUFA synthase for ARA production. Expression of the gene cluster in Escherichia coli induced production of ARA, demonstrating that the gene cluster encodes a PUFA synthase required for ARA biosynthesis.
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Effects of high hydrostatic pressure on coastal bacterial community abundance and diversity. Appl Environ Microbiol 2014; 80:5992-6003. [PMID: 25063663 DOI: 10.1128/aem.02109-14] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Hydrostatic pressure is an important parameter influencing the distribution of microbial life in the ocean. In this study, the response of marine bacterial populations from surface waters to pressures representative of those under deep-sea conditions was examined. Southern California coastal seawater collected 5 m below the sea surface was incubated in microcosms, using a range of temperatures (16 to 3°C) and hydrostatic pressure conditions (0.1 to 80 MPa). Cell abundance decreased in response to pressure, while diversity increased. The morphology of the community also changed with pressurization to a predominant morphotype of small cocci. The pressure-induced community changes included an increase in the relative abundance of Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, and Flavobacteria largely at the expense of Epsilonproteobacteria. Culturable high-pressure-surviving bacteria were obtained and found to be phylogenetically similar to isolates from cold and/or deep-sea environments. These results provide novel insights into the response of surface water bacteria to changes in hydrostatic pressure.
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Profile of Edward DeLong. Proc Natl Acad Sci U S A 2014; 111:9666-8. [DOI: 10.1073/pnas.1323425111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Brown A, Thatje S. Explaining bathymetric diversity patterns in marine benthic invertebrates and demersal fishes: physiological contributions to adaptation of life at depth. Biol Rev Camb Philos Soc 2014; 89:406-26. [PMID: 24118851 PMCID: PMC4158864 DOI: 10.1111/brv.12061] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 08/01/2013] [Accepted: 08/14/2013] [Indexed: 12/01/2022]
Abstract
Bathymetric biodiversity patterns of marine benthic invertebrates and demersal fishes have been identified in the extant fauna of the deep continental margins. Depth zonation is widespread and evident through a transition between shelf and slope fauna from the shelf break to 1000 m, and a transition between slope and abyssal fauna from 2000 to 3000 m; these transitions are characterised by high species turnover. A unimodal pattern of diversity with depth peaks between 1000 and 3000 m, despite the relatively low area represented by these depths. Zonation is thought to result from the colonisation of the deep sea by shallow-water organisms following multiple mass extinction events throughout the Phanerozoic. The effects of low temperature and high pressure act across hierarchical levels of biological organisation and appear sufficient to limit the distributions of such shallow-water species. Hydrostatic pressures of bathyal depths have consistently been identified experimentally as the maximum tolerated by shallow-water and upper bathyal benthic invertebrates at in situ temperatures, and adaptation appears required for passage to deeper water in both benthic invertebrates and demersal fishes. Together, this suggests that a hyperbaric and thermal physiological bottleneck at bathyal depths contributes to bathymetric zonation. The peak of the unimodal diversity-depth pattern typically occurs at these depths even though the area represented by these depths is relatively low. Although it is recognised that, over long evolutionary time scales, shallow-water diversity patterns are driven by speciation, little consideration has been given to the potential implications for species distribution patterns with depth. Molecular and morphological evidence indicates that cool bathyal waters are the primary site of adaptive radiation in the deep sea, and we hypothesise that bathymetric variation in speciation rates could drive the unimodal diversity-depth pattern over time. Thermal effects on metabolic-rate-dependent mutation and on generation times have been proposed to drive differences in speciation rates, which result in modern latitudinal biodiversity patterns over time. Clearly, this thermal mechanism alone cannot explain bathymetric patterns since temperature generally decreases with depth. We hypothesise that demonstrated physiological effects of high hydrostatic pressure and low temperature at bathyal depths, acting on shallow-water taxa invading the deep sea, may invoke a stress-evolution mechanism by increasing mutagenic activity in germ cells, by inactivating canalisation during embryonic or larval development, by releasing hidden variation or mutagenic activity, or by activating or releasing transposable elements in larvae or adults. In this scenario, increased variation at a physiological bottleneck at bathyal depths results in elevated speciation rate. Adaptation that increases tolerance to high hydrostatic pressure and low temperature allows colonisation of abyssal depths and reduces the stress-evolution response, consequently returning speciation of deeper taxa to the background rate. Over time this mechanism could contribute to the unimodal diversity-depth pattern.
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Affiliation(s)
- Alastair Brown
- Ocean and Earth Science, University of Southampton, National Oceanography Centre SouthamptonEuropean Way, Southampton, SO14 3ZH, U.K.
| | - Sven Thatje
- Ocean and Earth Science, University of Southampton, National Oceanography Centre SouthamptonEuropean Way, Southampton, SO14 3ZH, U.K.
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Ugalde JA, Gallardo MJ, Belmar C, Muñoz P, Ruiz-Tagle N, Ferrada-Fuentes S, Espinoza C, Allen EE, Gallardo VA. Microbial life in a fjord: metagenomic analysis of a microbial mat in Chilean patagonia. PLoS One 2013; 8:e71952. [PMID: 24015199 PMCID: PMC3756073 DOI: 10.1371/journal.pone.0071952] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 07/05/2013] [Indexed: 01/09/2023] Open
Abstract
The current study describes the taxonomic and functional composition of metagenomic sequences obtained from a filamentous microbial mat isolated from the Comau fjord, located in the northernmost part of the Chilean Patagonia. The taxonomic composition of the microbial community showed a high proportion of members of the Gammaproteobacteria, including a high number of sequences that were recruited to the genomes of Moritella marina MP-1 and Colwelliapsycherythraea 34H, suggesting the presence of populations related to these two psychrophilic bacterial species. Functional analysis of the community indicated a high proportion of genes coding for the transport and metabolism of amino acids, as well as in energy production. Among the energy production functions, we found protein-coding genes for sulfate and nitrate reduction, both processes associated with Gammaproteobacteria-related sequences. This report provides the first examination of the taxonomic composition and genetic diversity associated with these conspicuous microbial mat communities and provides a framework for future microbial studies in the Comau fjord.
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Affiliation(s)
- Juan A Ugalde
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America
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Carr SA, Vogel SW, Dunbar RB, Brandes J, Spear JR, Levy R, Naish TR, Powell RD, Wakeham SG, Mandernack KW. Bacterial abundance and composition in marine sediments beneath the Ross Ice Shelf, Antarctica. GEOBIOLOGY 2013; 11:377-395. [PMID: 23682649 DOI: 10.1111/gbi.12042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 04/13/2013] [Indexed: 06/02/2023]
Abstract
Marine sediments of the Ross Sea, Antarctica, harbor microbial communities that play a significant role in the decomposition, mineralization, and recycling of organic carbon (OC). In this study, the cell densities within a 153-cm sediment core from the Ross Sea were estimated based on microbial phospholipid fatty acid (PLFA) concentrations and acridine orange direct cell counts. The resulting densities were as high as 1.7 × 10⁷ cells mL⁻¹ in the top ten centimeters of sediments. These densities are lower than those calculated for most near-shore sites but consistent with deep-sea locations with comparable sedimentation rates. The δ¹³C measurements of PLFAs and sedimentary and dissolved carbon sources, in combination with ribosomal RNA (SSU rRNA) gene pyrosequencing, were used to infer microbial metabolic pathways. The δ¹³C values of dissolved inorganic carbon (DIC) in porewaters ranged downcore from -2.5‰ to -3.7‰, while δ¹³C values for the corresponding sedimentary particulate OC (POC) varied from -26.2‰ to -23.1‰. The δ¹³C values of PLFAs ranged between -29‰ and -35‰ throughout the sediment core, consistent with a microbial community dominated by heterotrophs. The SSU rRNA gene pyrosequencing revealed that members of this microbial community were dominated by β-, δ-, and γ-Proteobacteria, Actinobacteria, Chloroflexi and Bacteroidetes. Among the sequenced organisms, many appear to be related to known heterotrophs that utilize OC sources such as amino acids, oligosaccharides, and lactose, consistent with our interpretation from δ¹³CPLFA analysis. Integrating phospholipids analyses with porewater chemistry, δ¹³CDIC and δ¹³CPOC values and SSU rRNA gene sequences provides a more comprehensive understanding of microbial communities and carbon cycling in marine sediments, including those of this unique ice shelf environment.
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Affiliation(s)
- S A Carr
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO, USA
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